Bone harvesting device for bone implants

Abstract

Provided herein are medical devices and methods for treating bone fractures. The medical device includes a body, a scaffold within the body, and a means for concentrating bone growth throughout the body. The device is designed to minimize shear stress at the distal tip and disperse micromotion to promote bone ingrowth. The scaffold may include a triple period minimal surface (TPMS) having a repeating pattern of cubes that define walls within the scaffold, and the TPMS may be helically wrapped around a central axis of the device. The device may also contain biological agents and may accommodate homemade products. In some embodiments, the medical device is a bone screw or pedicle screw designed to reduce common problems such as screw loosening, screw backout, and rod breakage. The treatment method includes implanting the medical device into a patient's bone to aid in fracture healing.

Description

[Technical Field]

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 422,640, filed November 4, 2023, the disclosure of which is incorporated by reference in its entirety for all purposes.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to scaffolding materials that resemble natural bone, medical devices made from the scaffolding materials, and related methods for bone implants.

[0003] Spinal fusion is a commonly indicated procedure for managing common degenerative conditions, including fractures, instability, and low back pain. Fusion uses bone grafts and hardware, such as pedicle screws, to encourage two vertebral bodies to grow together. The traditional lumbar implant design is a smooth-threaded pedicle screw that is fixed to the vertebrae with a rod to hold the corrective height and angle until fusion is achieved.

[0004] Low back pain is estimated to affect 60-80% of people worldwide. Between 1998 and 2008, the number of annual lumbar fusion surgeries performed in the United States increased from 77,682 to 210,407. Unfortunately, the overall failure rate of lumbar spine surgeries is high, approximately 10-46%.

[0005] A review of spinal fusion surgery in the PubMed database identified 11,692 patients. There were 3,646 complications. The mean age at surgery was 53.3 years (range: 25-77 years), and the mean follow-up was 3.49 years (range: 6 weeks-9.7 years). Major perioperative complications occurred at an average rate of 18.5%. Minor perioperative complications occurred at an average rate of 15.7%. Long-term complications occurred at an average rate of 20.5%.

[0006] Despite advances in technology and surgical techniques, these rates have remained substantially unchanged over the years. For example, lumbar interbody fusion (LIF) techniques have advanced due to computer navigation, augmented reality, minimally invasive surgical (MIS) approaches, disc arthroplasty, bone-stimulating pedicle screws, and bone void filler options. Nevertheless, due to an increasing patient population and high failure rates, the number of patients developing failed back surgery syndrome (FBSS) continues to increase. (FBSS is when the results of lumbar spine surgery do not meet the preoperative expectations of the patient and surgeon.)

[0007] The gold standard for lumbar interbody fusion consists of inserting smooth-threaded screws into each pedicle (two per vertebral level) and placing rods in the tulip heads of the pedicle screws to stabilize the structure until fusion is achieved. However, since 1975, few technological advances have been made in spinal stabilization systems, and these configurations do not address important long-term stability issues related to bone mineral density quality and patient health. Hardware used in lumbar fusion procedures is subject to significant forces that can cause hardware breakage and loosening (the so-called "windshield wiper effect"). Estimates of the frequency of screw loosening during spinal fusion vary significantly, but recent reports estimate a loosening rate of over 40%, with approximately 10% being partial pullouts. This loosening due to lack of fusion can put nerves or blood vessels at risk, often necessitating hardware removal and repeat surgery.

[0008] Unfortunately, spinal revision surgery also has a low success rate. Secondary revision cases have a 30% success rate, third procedures 15%, and fourth surgical interventions 5%. Furthermore, adult spinal deformity patients who have endured two or more previous revisions exhibit more coronal and sagittal imbalances and worse functional status. Other potential complications of LIF include dural tears, nerve injury, pseudarthrosis, infection, and wound healing problems.

[0009] Another complication of lumbar fusion surgery is infection. Surgical site infections (SSIs) represent a major healthcare challenge, causing approximately 8,000 deaths annually. The combined direct and indirect costs attributable to SSIs are estimated to be between $1 and $10 billion annually. Instrumented spinal procedures pose a greater risk of SSI and result in higher infection rates compared to other orthopedic procedures. SSIs resulting from spinal surgery are estimated to occur at a rate of 0.2% to 16.7%. A recent meta-analysis suggested that instrumented spinal procedures result in an SSI rate of 4.4%. Deep incision and organ space SSIs account for 80% of these infections and are associated with increased morbidity, longer hospital stays, and greater healthcare costs.

[0010] Furthermore, bone mineral density decreases after medical devices are implanted, regardless of the material used. This loss contributes to common medical device failures, including screw loosening, screw backout, and rod breakage. While many devices promote fusion within interbody cages, none have been developed for scaffolding that increases bone mineral density within vertebral bodies. Additionally, the structure of cortical bone within vertebrae differs from bone in other parts of the human body.

[0011] These challenges regarding long-term stability, including bone quality and functional ability to heal, remain unmet. None of the prior art addresses the top two reasons for implant failure revision: pedicle screw backout and rod breakage before the patient achieves fusion. Smooth-threaded pedicle screws and rods do not address bone mineral density quality and patient health. Summary of the Invention

[0012] The present disclosure provides a medical device comprising a body, a scaffold located within the body, and a means for concentrating bone growth disposed on the body, the device being designed to minimize shear stress on the distal tip and distribute micromotion throughout the medical device, thereby promoting bone ingrowth.

[0013] The present disclosure also provides a method of treating a bone fracture in a patient in need thereof, the method comprising implanting a medical device into the patient's bone, the medical device may be any one of the devices disclosed herein.

[0014] Additional embodiments and features are set forth in part in the description that follows, and will become apparent to those skilled in the art upon examination of the specification or may be learned by practice of the embodiments discussed herein. A further understanding of the nature and advantages of some embodiments may be realized by reference to the remaining portions of the specification and the drawings, which form a part of this disclosure. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a top view of a diagram showing a pedicle screw implanted through a pedicle into a vertebral body of a vertebra. [Figure 2] FIG. 1 shows a side view of an embodiment of a pedicle screw 3D printed in titanium. [Figure 3] 3 shows a top view of the pedicle screw of FIG. 2. [Figure 4] 3 shows a bottom view of the pedicle screw of FIG. 2. [Figure 5] FIG. 1 shows a side view of an embodiment of a pedicle screw 3D printed with a scaffold disclosed herein. [Figure 6] 6 shows a top view of the pedicle screw of FIG. 5. [Figure 7] FIG. 6 shows a bottom view of the pedicle screw of FIG. 5 . [Figure 8] FIG. 1 shows a side view of another embodiment of a pedicle screw 3D printed with a scaffold disclosed herein. [Figure 9] 9 shows a top view of the pedicle screw of FIG. 8. [Figure 10] 9 shows a bottom view of the pedicle screw of FIG. 8. [Figure 11] FIG. 1 shows a side view of an embodiment of a porous pedicle screw. [Figure 12] 12 shows an exploded view of the porous pedicle screw of FIG. 11 with a tulip and pin. [Figure 13]12 shows a top view of the cap of the porous pedicle screw of FIG. 11 . [Figure 14] FIG. 12 shows a side view of the cap of the porous pedicle screw of FIG. 11 . [Figure 15] FIG. 12 shows a perspective view of the saddle of the porous pedicle screw of FIG. 11 . [Figure 16] 13 shows a perspective view of the tulip of FIG. 12. [Figure 17] 10 shows a screw with bone harvesting features located along the distal portion of the screw, but not along the proximal portion of the screw. [Figure 18] 18 shows the proximal portion of the screw of FIG. 17 without the bone harvesting feature. [Figure 19] 18 shows the distal portion of the screw of FIG. 17 having bone harvesting features. [Figure 20] 18 shows a cross section of the screw of FIG. 17 taken along line AA. [Figure 21] 18 shows a cross section of the screw shown in FIG. 17 . [Figure 22] Shows a two-dimensional slice through the Schwartz diamond mathematical field. [Figure 23] 23 shows a three-dimensional cross section of the unthickened surface of FIG. 22. [Figure 24] 24 shows a cylindrical remapping of the unthickened surface of FIG. 23 after transformation to polar space. [Figure 25] 24 shows a remap of FIG. 24 without shear. [Figure 26] 25 shows a remap of FIG. 25 with shear. [Figure 27] 27 shows the thickened surface of FIG. 26 using absolute value operations. [Figure 28] Shows the sheet-like structure of the Schwarz diamond lattice after thickening and subtraction. [Figure 29] FIG. 29 shows the thin-walled lattice field of FIG. 28 intersected with a 3D geometric space that defines where the lattice resides to define the scaffold. [Figure 30] FIG. 1 shows a perspective view of a porous pedicle screw presenting a diamond structural lattice. [Figure 31] FIG. 31 shows a rear view of the porous pedicle screw of FIG. 30. [Figure 32]FIG. 31 shows a front view of the porous pedicle screw of FIG. 30. [Figure 33] FIG. 31 shows an enlarged inset of a front view of the porous pedicle screw of FIG. 30 highlighting the scaffolding. [Figure 34] 31 shows a top view of the porous pedicle screw of FIG. 30. [Figure 35] 31 shows a bottom view of the porous pedicle screw of FIG. 30. [Figure 36] FIG. 10 shows a perspective view of another embodiment of a porous pedicle screw presenting a diamond structural lattice with bone harvesting features at the distal tip and textured threads at the proximal end. [Figure 37] 37 shows a rear view of the porous pedicle screw of FIG. 36. [Figure 38] FIG. 37 shows a front view of the porous pedicle screw of FIG. 36. [Figure 39] FIG. 37 shows an enlarged inset of a front view of the porous pedicle screw of FIG. 36 highlighting the scaffolding. [Figure 40] 37 shows a top view of the porous pedicle screw of FIG. 36. [Figure 41] 37 shows a bottom view of the porous pedicle screw of FIG. 36.

[0016] The present disclosure will be readily understood from the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals indicate like structural elements, and in which: The drawings provide exemplary embodiments or aspects of the present disclosure and are not intended to limit the scope of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present disclosure provides a medical device comprising a body, a scaffold located within the body, and a means for concentrating bone growth disposed on the body, the device being designed to minimize shear stress on the distal tip and distribute micromotion throughout the medical device, thereby promoting bone ingrowth.

[0018] In some embodiments, the means for focusing bone growth within the medical device comprises at least one trephine for harvesting bone internally within the device.

[0019] In some embodiments, the medical device, whether or not it includes a trephine, is configured with an arcuate cross-sectional pattern that varies from the proximal end to the distal tip.

[0020] In some embodiments, the medical device is configured for placement within the internal cavity of a vertebral body. Upon coaxial rotation of the medical device, autograft is harvested within the scaffold.

[0021] In some embodiments, the medical device comprises threads with a concave profile, regardless of other characteristics.

[0022] In some embodiments, the scaffolding in the medical device comprises a triple period minimal surface (TPMS) with a repeating pattern of cubes that define the walls within the scaffold.

[0023] In some embodiments, the TPMS is a Schwarz diamond spirally wrapped around the central axis of the medical device and within the 3D geometric space for the scaffold.

[0024] In some embodiments, the TPMS is helically wound in a single helix. In some embodiments, the TPMS is helically wound in a double helix. In some embodiments, the TPMS is helically wound in a triple helix. In some embodiments, the TPMS is helically wound in a quadruple helix. In some embodiments, the medical device comprises three radial spokes per turn of the helix, regardless of whether the TPMS is helically wound in a single helix.

[0025] In some embodiments, the repeating cubic pattern within the medical device is about 1 mm to 3 mm in the X / Y / Z dimensions, e.g., about 1.5 mm to 2 mm, or about 1.8 mm in the X / Y / Z dimensions. In some embodiments, the helical windings of the medical device are defined by a period three times the size of the repeating cubic pattern. In some embodiments, the walls within the medical device are about 0.5 mm thick, regardless of other characteristics.

[0026] In some embodiments, the threads near the proximal end of the medical device are textured with a topography similar to that of the scaffold.

[0027] In some embodiments, the medical device is configured to contain one or more biological agents, regardless of other characteristics. In some embodiments, the medical device further comprises at least one homemade product that is sprayed onto or injected through the device.

[0028] In some embodiments, the body of the medical device is a shaft. In some embodiments, the medical device is a bone screw. In some embodiments, the medical device reduces one or more of loosening, screw backout, rod breakage, and bone mineral density loss. In some embodiments, the medical device comprises a fluted tip.

[0029] In some embodiments, the medical device is a pedicle screw.

[0030] The present disclosure also provides a method of treating a bone fracture in a patient in need thereof, the method comprising implanting a medical device into the patient's bone, the medical device may be any one of the devices disclosed herein.

[0031] scaffold Surface curvature and Minkowski bone morphological curvature maps (functions that recover the concept of distance in linear space) show a significantly different porous matrix in the trabecular bone within the vertebrae relative to other regions of the skeletal anatomy. The loads of conventional smooth-threaded pedicle screws may be too high for the vertebrae due to the loss of bone mineral density after implantation.

[0032] The porous 3D printed scaffold promotes osseointegration, fusion, and fixation within the bone. The open framework of the scaffold resembles that of natural bone. This similarity allows the physician to make patient-specific choices using other agents to promote bone formation and / or stabilize the device.

[0033] Triangular porosity patterns have been used in the prior art. Rounded, square / rectangular shapes, and various patterns align more closely with the natural vertebral structure. Furthermore, the scaffold structure reduces the likelihood of revision of the medical device from which the scaffold is fabricated, for example, due to screw loosening, screw backout, rod breakage, and bone mineral density loss.

[0034] In some embodiments, the disclosed scaffolds and devices integrate orthopedic products with tissue engineering and prevent the risk of delayed bone union to the implanted device.

[0035] In some embodiments, the scaffold comprises one or more structural cues selected from porosity, pore size, particle size, and surface topography. Porosity and pore size cues indicate mechanical strength, cell retention, and cell migration. Particle size enhances signal protein absorption, cell adhesion, cell proliferation, and cell adhesion. Surface topography enhances signal-specific surface area, cell adhesion, and material-tissue interface. Other scaffold characteristics include pH and wall thickness. In some embodiments, the one or more structural cues enhance at least one of pluripotent mesenchymal stem cell (MSC) differentiation, osteoblast growth, extracellular matrix (ECM) deposition, and new bone formation. In some embodiments, new bone formation occurs following MSC differentiation, osteoblast growth, ECM deposition, or a combination thereof.

[0036] bone Bones can generally be classified as cancellous bone and cortical bone. "Cancellous bone," also called "trabecular bone" or "spongy bone," is a light, porous bone that encloses numerous large spaces, giving it a honeycomb or spongy appearance. The bone matrix or skeleton is organized into a three-dimensional lattice of bony processes called trabeculae, which are arranged along stress lines. The spaces between are often filled with bone marrow and blood vessels. In cross section, the trabeculae of cancellous bone may appear like septa. However, they differ topologically in three dimensions; trabeculae are roughly rod-like or column-like, while septa are sheet-like.

[0037] Trabecular bone comprises approximately 20% of the human skeleton and provides structural support and flexibility without compact bone. It is found in most regions of bone that are not subjected to significant mechanical stress. It makes up many of the bulky ends (epiphyses) of long bones and is the major component of the ribs, scapulae, flat bones of the skull, and various short, flat bones elsewhere in the skeleton.

[0038] Due to the increasing frequency of total joint replacement surgery and its impact on bone remodeling, understanding the stress-related and adaptive processes of trabecular bone has become a central interest for bone physiologists. To understand the role of trabecular bone in age-related bone structure and design for bone-implant systems, the mechanical properties of trabecular bone are studied as a function of anatomical location, density, and age. Mechanical factors, including elastic modulus, uniaxial strength, and fatigue properties, are also investigated.

[0039] High porosity makes trabecular bone flexible. Large variations in architecture result in high heterogeneity. Elastic modulus and strength vary inversely with porosity and are highly dependent on the porous structure. Typically, cancellous bone has a porosity of 75% to 95%. Density is 0.2 to 0.8 g / cm. 3 Porosity can reduce the strength of bone, but it can also reduce its weight.

[0040] Porosity and structure affect the strength of a material. Therefore, the microstructure of trabecular bone is typically oriented. The porosity "grains" are aligned when mechanical stiffness and strength are greatest. Due to the directionality of the microstructure, the mechanical properties of trabecular bone are highly anisotropic. The Young's modulus of trabecular bone, including vertebrae, is 800-14,000 MPa. Its breaking strength is 1-100 MPa.

[0041] "Cortical bone" or "compact bone" is much denser than cancellous bone. It forms the hard exterior (cortex) of bone. Cortical bone gives bone its smooth, white, and solid appearance. It accounts for approximately 80% of the total bone mass in the adult skeleton.

[0042] Trabecular bone is usually surrounded by a shell of compact bone, which provides greater strength and rigidity. The open structure of trabecular bone allows it to attenuate sudden stresses, such as load transmission through joints. Varying ratios of bone to air space are found in different bones, depending on the need for strength or flexibility. Trabecular bone also has a relatively high level of metabolic activity.

[0043] "Wolff's Law" states that a healthy human or animal's bone adapts to the loads it is placed on. For example, if the load on a particular bone increases, the bone will remodel itself over time to become stronger to resist the load.

[0044] vertebrae Each vertebra is an irregular bone in the spinal column of the spine, with a complex structure made up of bone and some hyaline cartilage, the proportions of which vary according to the segment of the skeleton and the vertebrate species.

[0045] The basic structure of vertebrae varies. The majority of the body is the vertebral body, and the central portion is the vertebral body. The superior and inferior surfaces of the vertebral body provide attachment to the intervertebral discs. The posterior portion forms the vertebral arch with 11 sections consisting of two pedicles, two laminae, and seven processes. The laminae provide attachment to the ligamentum flavum (ligaments of the spine). There are notches in the vertebra formed by the shape of the pedicles that form the intervertebral foramina when the vertebrae articulate. These foramina are the entrance and exit canals for spinal nerves. The vertebral body and vertebral arch form the vertebral foramen, a larger central opening that houses the spinal canal and surrounds and protects the spinal cord.

[0046] The pedicles and laminae form the vertebral arch. Two pedicles extend from the sides of the vertebral body, joining it to the vertebral arch. The pedicles are short, thick processes that extend posteriorly, one on each side, from the posterior junction of the superior surface of the vertebral body. From each pedicle, broad plates called "lamina" project posteriorly and medially to join and complete the vertebral arch and form the posterior boundary of the vertebral foramen, thereby completing the triangular shape of the vertebral foramen. The superior surfaces of the lamina are roughened to provide attachment to the ligamentum flavum. These ligaments connect the lamina of adjacent vertebrae along the length of the spine, from the level of the second cervical vertebra. Above and below the pedicles are shallow notches called vertebral notches (superior and inferior). When vertebrae articulate, the notches align with notches in the adjacent vertebrae, forming the intervertebral foraminal openings. The foramens allow spinal nerves and associated blood vessels to enter and exit each vertebra. Articulating vertebrae provide strong support for the body.

[0047] device The present disclosure provides devices formed from the scaffolds disclosed herein. In some embodiments, the devices are cannulated and fenestrated with the scaffold. In some embodiments, the devices comprise a threaded distal region, optionally a threaded central region, and optionally a threaded proximal region, responsive to compressive force.

[0048] In some embodiments, the device is selected from pedicle screws, cannulated pedicle screws, fenestrated pedicle screws, capitate screws, capitate screws, headless screws, traumatic hip fracture devices, glenoid cages, glenoid cage screws, traumatic plates, tibial stems, femoral stems, hammertoe implants, nail fusion systems, Charcot foot deformity correction, radial head fracture devices, high tibial osteotomies, deformity corrections, corpectomy cages, oncological corrections, anchors, dental implants, maxillofacial implants, and sports medicine anchors.

[0049] In some embodiments, the device is selected from a hip fracture system, a reverse total shoulder, a dental implant, upper extremity hardware, lower extremity hardware, a total joint replacement implant, a total joint revision implant, spinal fusion, spinal arthroplasty, regenerative therapy, a cartilage implant, maxillofacial hardware, and a cardiac implant.

[0050] In some embodiments, the screw is configured with features that encourage bone to grow through the structure of the screw from opposite sides, allowing bone to connect through the screw. In some embodiments, the features are narrow, such as through the thread, thereby allowing rapid through-growth. In some embodiments, the features are deeper, such as through a small diameter, thus providing a stronger connection. In some embodiments, the features are voids within the screw or are porous or structured to encourage bone growth. In some embodiments, the structures collect autograft material within channels inside the device. In some embodiments, the features are impregnated with one or more polymers.

[0051] In some embodiments, the device is configured to enhance stabilization and fixation of the bone screw within the bone and improve bone mineral density. In some embodiments, the device includes a spinal implant configured to engage cortical and cancellous bone within the vertebra. In some embodiments, the device is configured to resist and / or prevent toggling of the bone screw when the bone screw is engaged with dense cortical bone and less dense cancellous bone resulting from loads on the bone screw. In some embodiments, the device is configured to resist and / or prevent loosening of the bone screw from the cortical bone, and in some cases, pull-out of the bone screw from the vertebra. In some embodiments, the device is configured to promote bone penetration growth to improve bone attachment to the bone screw. In some embodiments, the bone screw is anchored to the bone, thereby reducing pull-out. In some embodiments, the bone screw is designed to diffuse micromotion and reduce shear to enhance bone mineral density.

[0052] In some embodiments, the device includes a bone screw with bone-penetrating growth through the shaft of the screw to reduce toggling and potential failure of the screw. In some embodiments, the bone screw includes features that allow bone to grow through the structure of the bone screw from opposite sides, allowing bone to connect through those bone screw structures. In some embodiments, the bone screw includes features that may be narrow, such as through the threads of the bone screw, which allows for rapid bone-penetrating growth. In some embodiments, the bone screw includes features that may be deeper, such as through a small diameter, which provides a larger volume of bone-penetrating growth. In some embodiments, the bone screw includes features that may be voids or cavities through both sides of the bone screw and / or voids or cavities that lead into or out of the same or adjacent surfaces. In some embodiments, the voids or cavities may contain scaffolding for bone attachment or a porous structure on the surface of the void.

[0053] In some embodiments, the bone screw includes features or structures that may be disposed along a shaft portion of the bone screw. In some embodiments, the bone screw includes features or structures that may be continuously disposed along a surface of the bone screw, such as along the distal end. In some embodiments, the bone screw includes features or structures that may be discontinuously disposed along a portion of the bone screw. In some embodiments, the bone screw includes features or structures that may include a scaffold or polymer.

[0054] In some embodiments, the device comprises a spinal implant having a hybrid configuration that combines a manufacturing method, e.g., one or more traditional manufacturing features and materials, with a manufacturing method, e.g., one or more additive manufacturing features and materials. In some embodiments, the additive manufacturing comprises 3D printing. In some embodiments, the additive manufacturing comprises fused deposition modeling, selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, layered object manufacturing, and stereolithography. In some embodiments, the additive manufacturing comprises one or more selected from rapid prototyping, desktop, direct, digital, instant, and on-demand manufacturing. In some embodiments, the device comprises a spinal implant that is manufactured, grown, or otherwise printed by a fully additive process.

[0055] In some embodiments, the device comprises one or more selected from demineralized bone matrix (DBM), pre-packed DBM, pre-packed synthetic DBM, unpacked DBM, and magnesium-infused titanium.

[0056] In some embodiments, the device includes a spinal implant, such as a bone screw, manufactured by combining traditional and additive manufacturing methods. In some embodiments, the bone screw is manufactured by applying additively manufactured materials, allowing the bone screw to benefit from additively manufactured materials and properties. In some embodiments, traditional materials are used when advantages, such as physical properties and cost, are superior to those obtained from additively manufactured features and materials.

[0057] In some embodiments, the device treats a spinal disorder selected from degenerative disc disease, herniated disc, osteoporosis, spondylolisthesis, stenosis, scoliosis, other curvature abnormalities, kyphosis, tumors, and fractures.

[0058] "Treating" a disease or condition or "treatment" of a disease or condition refers to performing a procedure that may include administering one or more drugs to a patient, using an implantable device, and / or using a disease-treating instrument, e.g., a microdiscectomy instrument, to remove bulging or herniated disc portions and / or bone spurs to alleviate the signs or symptoms of the disease or condition. Treating or treatment does not require complete alleviation of signs or symptoms, does not require a cure, and specifically includes procedures that have a marginal effect on the patient. For example, treatment can include inhibiting the disease, e.g., halting its development, or relieving the disease, e.g., causing regression.

[0059] "Prevention" refers to the alleviation of signs or symptoms of a disease or condition before they appear. Thus, prevention includes preventing a disease from occurring in a patient who may be susceptible to the disease but has not yet been diagnosed as having it.

[0060] "Tissue" includes soft tissue, ligament, tendon, cartilage, and / or bone. In some embodiments, the tissue is cancellous bone, cortical bone, or corticocancellous bone.

[0061] In some embodiments, the device is used in conjunction with other bone and bone-related applications, including diagnostics and therapeutics. In some embodiments, the device is alternatively used in surgical treatment of patients in prone or supine positions, and / or with various surgical approaches to the spine, including anterior, posterior, posterior midline, lateral, posterolateral, and / or anterolateral approaches, to other body regions, such as the maxillofacial and extremities. The device may alternatively be used with procedures to treat the lumbar, cervical, thoracic, sacral, and pelvic regions of the spine. The device may also be used on animals, bone models, and other non-biological substrates, for example, in training, testing, and demonstrations.

[0062] In some embodiments, the device is a custom medical device, hi some embodiments, the device is adapted for sports medicine.

[0063] In some embodiments, the device is temperature sensitive, hi some embodiments, the device is pH balanced.

[0064] In some embodiments, devices are fabricated with porosity having porogens that are spheroidal, cubic, rectangular, elongated, tubular, fibrous, disc-shaped, platelet-shaped, polygonal, or mixtures thereof. In some embodiments, the porosity is based on a plurality of macropores, micropores, nanopore structures, and / or combinations thereof.

[0065] In some embodiments, the device is fabricated from a biologically acceptable material suitable for medical use, including metals, synthetic polymers, ceramics, bone materials, and composites thereof, hi some embodiments, the device comprises one or more selected from metals, ceramics, rubber, hydrogels, rigid polymers, fabrics, bone materials, and composites thereof.

[0066] In some embodiments, the device comprises a metal selected from stainless steel alloys, aluminum, commercially pure titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, magnesium-infused titanium, cobalt-chromium alloys, superelastic metal alloys such as Nitinol, and superelastic plastic metals such as Gum Metal®. In some embodiments, the device comprises a ceramic such as calcium phosphate (e.g., Skelite™) and composites thereof. In some embodiments, the device comprises a rubber selected from polyaryletherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone (PEK), carbon-PEEK composites, PEEK-BaSO4 rubber, polyethylene terephthalate (PET), silicone, polyurethane, silicone-polyurethane copolymer, and polyolefin rubber. In some embodiments, the device comprises a hydrogel. In some embodiments, the device comprises a fabric. In some embodiments, the device comprises a rigid polymer selected from polyphenylene, polyimide, polyetherimide, polyethylene, and epoxy. In some embodiments, the device comprises a bone material selected from autograft, allograft, xenograft, or transgenic cortical and / or cortical-cancellous bone. In some embodiments, the device comprises tissue growth factors or differentiation factors. In some embodiments, the device comprises absorbable materials such as composites of metal and calcium-based ceramics, composites of PEEK and calcium-based ceramics, composites of PEEK and absorbable polymers, fully absorbable materials such as calcium-based ceramics, e.g., calcium phosphate, tricalcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate, or other absorbable polymers such as polyketides, polyglycolides, polytyrosine carbonates, polycaprolactones, and other combinations.

[0067] In some embodiments, the device comprises a rubber selected from polyaryletherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone (PEK), carbon-PEEK composite, PEEK-BaSO rubber, polyethylene terephthalate (PET), silicone, polyurethane, silicone-polyurethane copolymer, polyolefin rubber, synthetic collagen, and a collagen matrix. In some embodiments, the device comprises synthetic collagen. In some embodiments, the device comprises a collagen matrix.

[0068] In some embodiments, the device includes magnesium, vitamins, and minerals. "Vitamin" refers to an organic molecule (or a set of chemically closely related molecules, i.e., vitamers) that is an essential micronutrient required in small amounts by an organism for the proper functioning of its metabolism. While some sources list 14 vitamins, including choline, major health organizations typically list the following 13: vitamin A (as all-trans-retinol, all-trans-retinyl esters, and all-trans-beta-carotene and other provitamin A carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B 12 (cobalamin), vitamin C (ascorbic acid), vitamin D (calciferol), vitamin E (tocopherols and tocotrienols), and vitamin K (phylloquinone and menaquinone). In the context of nutrition, "mineral" refers to chemical elements required as essential nutrients by living organisms to perform functions necessary for life, and includes potassium, chlorine, sodium, calcium, phosphorus, magnesium, iron, zinc, manganese, copper, iodine, chromium, molybdenum, selenium, and cobalt.

[0069] In some embodiments, the device comprises a metal selected from iron, stainless steel alloys, aluminum, commercially pure titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, magnesium-infused titanium, cobalt chromium alloys, superelastic metal alloys such as Nitinol, and superelastic plastic metals such as Gum Metal®. In some embodiments, the device comprises titanium. In some embodiments, the device comprises iron.

[0070] In some embodiments, the device is fabricated or 3D printed from materials such as titanium, titanium alloys, cobalt chrome, carbon fiber, magnesium-infused titanium, iron, or stainless steel. In some embodiments, the device is fabricated from a shape memory alloy or shape memory polymer, allowing the device to conform to the anatomical shape of the patient's body.

[0071] In some embodiments, the device comprises magnesium-infused titanium. In some embodiments, the device comprises an angiotensin receptor blocker coating. In some embodiments, the device comprises a type 1 cartilage collagen coating. In some embodiments, the device is infused with an antibiotic.

[0072] In some embodiments, the device is employed to treat a diseased section of a vertebra. A physician gains access to a surgical site containing the vertebra by any suitable method, such as tissue dissection and retraction. In some embodiments, the device comprises a bone screw for augmenting the surgical treatment. In some embodiments, the device may be pre-assembled for delivery to the surgical site or may be assembled in situ. In some embodiments, the device is modified, removed, or replaced, in whole or in part.

[0073] In some embodiments, the device is used in conjunction with a surgical method or technique, including, but not limited to, open surgery, minimally invasive surgery (MIS), and percutaneous surgical implantation, whereby the vertebrae are accessed through a small incision, or the sleeve provides a protected passageway to the area. Once access to the surgical site is gained, a surgical procedure, such as a corpectomy or discectomy, can be performed to treat the disease or disorder.

[0074] In some embodiments, the surface of the device comprises a non-solid structure, such as a lattice, hi some embodiments, the non-solid structure comprises a porous structure or a trabecular bone structure.

[0075] In various embodiments, the non-solid configuration is configured to provide one or more pathways for supporting bone growth within one surface of the device and from one surface of the device to the opposite surface. In some embodiments, the lattice comprises one or more portions, layers, or substrates. In some embodiments, one or more portions, layers, or substrates of the lattice are arranged side-by-side, offset, staggered, stepped, tapered, end-to-end, spaced apart, in series, or parallel. In some embodiments, the lattice defines a thickness that can be uniform, wavy, tapered, increasing, decreasing, variable, offset, stepped, arcuate, angled, and / or staggered. In some embodiments, one or more lattice layers are arranged in a side-by-side and parallel orientation within the wall. In some embodiments, the lattice comprises one or more layers of a material matrix.

[0076] In some embodiments, the grid comprises a plurality of nodes and openings arranged in rows and columns or randomly, in some embodiments, the plurality of nodes and openings are arranged in series, and in some embodiments, the plurality of nodes and openings are arranged in parallel.

[0077] In some embodiments, the lattice forms a rasp-like configuration. In some embodiments, the lattice is configured to engage tissue. In some embodiments, the engagement of the lattice cuts, shaves, shears, dissects, or breaks the tissue. In some embodiments, the lattice comprises a configuration selected from a cylindrical, circular, elliptical, oval, triangular, polygonal with flat or arcuate sides, irregular, uniform, non-uniform, consistent, variable, or horseshoe shape.

[0078] U-shaped, or kidney bean-shaped. In some embodiments, the lattice is rough, textured, or porous.

[0079] For example, it may be semi-porous, dimpled, knurled, toothed, grooved, or polished to engage and cut tissue. In some embodiments, the lattice forms tunnels that are configured to guide, drive, or direct the cut tissue into the openings, such as fusing the device to the tissue.

[0080] Screw In some embodiments, the device is a screw, hi some embodiments, the screw is selected from a posted screw, a pedicle screw, a bolt, a bone screw for a lateral plate, an interbody screw, a monoaxial screw, a fixed angle screw, a polyaxial screw, a lateral loading screw, a sagittal adjustment screw, a parasagittal adjustment screw, an awl tip, a dual rod polyaxial screw, a midline lumbar fusion screw, and / or a sacral screw.

[0081] In some embodiments, the device is a bone screw. In some embodiments, the device is a pedicle screw. Referring to FIG. 1 , a pedicle screw is shown implanted through a pedicle into the vertebral body of a vertebra. In some embodiments, the pedicle screw has a cage with a polymer retained within a cannulated and / or fenestrated portion of the screw.

[0082] In some embodiments, the inner core of the screw is a trephine for harvesting and harvesting autograft material at and / or during screw insertion.

[0083] In some embodiments, the post-implantation option prevents revision surgery by injecting polymer through the screw.

[0084] In some embodiments, the pedicle screws do not exhibit screw loosening, screw backout, rod breakage, or bone mineral density loss.

[0085] In some embodiments, the pedicle screws reduce one or more of screw loosening, screw backout, rod breakage, and bone mineral density loss.

[0086] The disclosed screw focuses bone growth throughout the shaft to minimize shear stress at the distal tip and distribute micromotion evenly throughout the screw to promote bone ingrowth.

[0087] In some embodiments, the pedicle screw scaffolding provides options for simple to complex bone mineral densities and immunocompromised patients. In some embodiments, the scaffolding is impregnated with one or more biologics, antibiotics, demineralized bone matrix, nanotechnology, or tissue engineering therapies.

[0088] 5-16, the structure of the pedicle screws 300, 400, 500 is specifically designed to support bone ingrowth through the pedicle screws 300, 400, 500 by utilizing a scaffold 280 similar to the natural trabecular bone within the vertebral body. In combination with the threads 230 and scaffold 280, the core 260 aids in autograft harvesting, forcing the autograft into the built-in channels within the core 260 of the pedicle screws 300, 400, 500 during the insertion process. The walls surrounding the pores act as a trephine, harvesting the autograft. This structure also aids in the structural integrity of the pedicle screws 300, 400, 500, resisting bone mineral density loss and reducing micromotion.

[0089] With reference to FIGS. 2-16 , the pedicle screws 200, 300, 400, 500 disclosed herein overcome many of the shortcomings of prior art pedicle screws. In some embodiments, the pedicle screws lack a windshield wiper effect. In some embodiments, the pedicle screws resist backout. In some embodiments, the pedicle screws do not exhibit excessive micromotion. In some embodiments, the pedicle screws have a low frequency of low-virulence microorganisms detected by sonication, for example, due to the sterilization and packaging of each individual screw. In some embodiments, the head and shaft of the pedicle screw resist breakage. In some embodiments, the pedicle screws are adapted to each type of bone quality. In some embodiments, the pedicle screws have an appropriate thread depth. In some embodiments, the pedicle screws withstand insertion torque, especially at the head-to-screw interface. In some embodiments, the fatigue life of the pedicle screw is not reduced when the screw is fully inserted. In some embodiments, the pedicle screws have good instrumentation. In some embodiments, the pedicle screws achieve angulation for rod acceptance. In some embodiments, the pedicle screws do not have cyclic loading based on physiological conditions during ambulation. In some embodiments, the pedicle screws do not require simultaneous C6 or T1 buttress pedicles and do not fail long segment posterior cervical fusion. In some embodiments, the pedicle screws distribute stress. In some embodiments, the pedicle screws do not immunocompromise the patient. In some embodiments, the pedicle screws do not include PEEK. In some embodiments, the pedicle screws do not have tulip or locking cap stresses.

[0090] In some embodiments, the distal tip 220 of the pedicle screw 200, 300, 400, 500 has a surface configuration selected from angled, irregular, uniform, non-uniform, offset, staggered, tapered, arcuate, wavy, mesh, porous, semi-porous, dimpled, pointed, textured, or a combination thereof. In some embodiments, the distal tip 220 includes peg configurations, barbs, extension elements, raised elements, ribs, and / or spikes to provide a fabrication platform for forming a portion thereon via additive manufacturing. In some embodiments, the distal tip 220 has a cross-sectional configuration selected from elliptical, oval, triangular, square, polygonal, irregular, uniform, non-uniform, offset, staggered, tapered, or a combination thereof.

[0091] In some embodiments, the pedicle screw 200, 300, 400, 500 includes a thread 230 extending between the proximal end 210 and the distal tip 220. In some embodiments, the thread 230 includes an external thread form. In some embodiments, the thread form includes a leading edge 231 having a leading surface 235 and a trailing edge 232 having a trailing surface 236. The leading surface 235 defines a first opening 251. The trailing surface 236 defines a second opening 252. In some embodiments, the first and second openings 251, 252 are axially aligned. In some embodiments, the first and second openings 251, 252 are circumferentially disposed about the thread form.

[0092] In some embodiments, the anterior surface 235 and / or the posterior surface 236 comprise at least one tissue collection member. In some embodiments, the tissue collection member comprises a cutting edge. In some embodiments, the cutting edge is configured to be rasp-like. In some embodiments, the cutting edge is configured to engage tissue and, for example, cut, shave, shear, incise, or disrupt the tissue. In some embodiments, the cutting edge is configured to be cylindrical, circular, oval, oval, triangular, polygonal, have flat or arcuate sides, irregular, uniform, non-uniform, consistent, variable, horseshoe-shaped, U-shaped, or kidney-shaped. In some embodiments, the cutting edge is rough, textured, porous, semi-porous, dimpled, knurled, toothed, grooved, or polished to engage and cut tissue. In some embodiments, the cutting edge forms a tunnel configured to guide, drive, or direct the cut tissue into a gap, such as fusing a thread with tissue.

[0093] By manipulating the pedicle screw 200, 300, 400, 500, for example by rotation or translation, the cutting edges 271 of the screw cut and guide tissue or bone into the core 260, thereby promoting bone growth and fusion to the pedicle screw 200, 300, 400, 500. In some embodiments, tissue is embedded in the core 260, promoting bone growth and fusion to the pedicle screw 200, 300, 400, 500. In some embodiments, a lattice is disposed within the core 260, forming a scaffold 280 for bone growth.

[0094] In some embodiments, threads 230 are configured to be fine, closely spaced, or shallow to engage tissue. In some embodiments, threads 230 have an increased pitch and equal lead between thread turns. In some embodiments, threads 230 have a smaller pitch or more thread turns per axial distance to establish stronger fixation with or resist loosening from tissue. In some embodiments, threads 230 are configured to be continuous along a portion. In some embodiments, threads 230 are configured to be intermittent, staggered, or discontinuous. In some embodiments, threads 230 include a single thread turn.

[0095] In some embodiments, the thread comprises a plurality of separate threads. In some embodiments, the thread has a concave profile.

[0096] In some embodiments, the threads 230 comprise piercing elements selected from, for example, nail configurations, barbs, expanding elements, raised elements, ribs, or spikes. In some embodiments, the threads 230 are configured as self-tapping or interrupted at the distal tip 220. In some embodiments, the distal tip 220 is rounded. In some embodiments, the distal tip 220 is self-drilling. In some embodiments, the distal tip 220 comprises a solid outer surface.

[0097] In some embodiments, the screws are 3D-printed porous pedicle screws. Their porosity mimics that of natural vertebrae, allowing stem cells, growth factors, and other proteins to attach and retain within the pedicle screw's structure, promoting bone growth through the screw and stabilizing the entire construct. During insertion into the vertebra, an integrated trephine collects autograft and regenerative cells within the porous matrix. The disclosed topography attracts osteogenic stem cells within and around the device, reducing macromotion of the overall construct. In some embodiments, the device allows surgeons to meet patient-specific needs, including, but not limited to, the option to spray / inject regenerative products to stimulate the osteogenic cascade, aggressively inject antibiotics into the screw scaffold for diabetes-prone infections, and inject bone cement to further stabilize the construct in severely osteoporotic bone.

[0098] In some embodiments, the screws reduce revision rates during spinal fusion, improve bone mineral density, and / or address patient-specific needs. In some embodiments, bone mineral density is improved, constructs are stabilized, and revision likelihood is reduced.

[0099] In some embodiments, the screw is a 3D printed titanium porous pedicle screw with a porous pattern throughout the screw similar to that of natural bone. Without wishing to be bound by theory, the function of the porous pattern is to attach to the surrounding bone, maintain bone-forming stem cells in place, and collect autograft bone within its porous structure. An advantage of the porous structure is the ability to inject polymers and regenerative therapies through the screw. In some embodiments, stem cell therapy is injected through the screw implant. In such embodiments, the likelihood of failure is reduced.

[0100] In some embodiments, the surgeon can inject or spray concentrated autologous stem cells onto the screw. Without being bound by theory, as the screw rotates during insertion into the vertebra, the pores of the screw use their built-in trephine to collect the autologous graft / stem cell mixture internally. The osteogenic stem cells then combine with the concentrated blood stem cells and signal the process of mutation and replication, forming more osteogenic cells within the screw, subsequently forming a bone healing cascade directed within and around the screw. In these embodiments, the combination of stem cell (a) osteoconductive (bone growth on the surface), (b) osteoinductive (cell recruitment for bone healing), and (c) osteogenic (bone development and formation) healing cascades improves bone mineral density and supports superior bone integration and pull-out strength.

[0101] In some embodiments, the patient is diabetic and prone to infection. In these embodiments, the surgeon can inject a mixture containing a calcium sulfate product and an antibiotic through the screw before or after insertion into the pedicle, or onto the screw in the pedicle, to provide antibiotic delivery to the area. In certain embodiments, the antibiotic is delivered for 2 to 6 weeks, thus reducing the likelihood of revision due to infection.

[0102] manufacturing The devices disclosed herein can be manufactured using a variety of methods. In some embodiments, manufacturing includes machining, such as subtractive, deformation, or transformation manufacturing. In some embodiments, manufacturing includes cutting, grinding, rolling, forming, molding, casting, forging, extruding, whirling, grinding, cold working, or a combination thereof. In some embodiments, manufacturing includes a portion of the device formed by a medical machining process. In some embodiments, machining uses computer numerically controlled (CNC) high-speed milling machines, Swiss machining devices, CNC turning with living tooling, wire EDM 4th axis, and combinations thereof. In some embodiments, manufacturing to fabricate a portion of the device includes a finishing process, such as laser marking, tumble blasting, bead blasting, microblasting, powder blasting, or a combination thereof.

[0103] In some embodiments, the device is manufactured per instructions from a computer and processor based on data in a selected configuration via digital rendering and / or additive manufacturing.

[0104] In some embodiments, the additive manufacturing comprises 3D printing. In some embodiments, the additive manufacturing is selected from fused deposition modeling, selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, layered object manufacturing, stereolithography, and combinations thereof. In some embodiments, the additive manufacturing comprises rapid prototyping, desktop manufacturing, direct manufacturing, direct digital manufacturing, digital fabrication, instant manufacturing, on-demand manufacturing, or combinations thereof.

[0105] In some embodiments, a portion of the device is fabricated by additive manufacturing and then mechanically attached to a surface of the device, for example, by welding, threading, adhesives, or crimping.

[0106] In one embodiment, the device is configured based on imaging from the patient's anatomy. Suitable imaging techniques include, but are not limited to, x-ray, fluoroscopy, computed tomography (CT), magnetic resonance imaging (MRI), surgical navigation, bone mineral density (DEXA), or any obtainable 2D or 3D image of the patient's anatomy. Selected configuration parameters of the device are collected, calculated, or determined. Examples of configuration parameters include, but are not limited to, imaging of the patient's anatomy, surgical treatment, patient history data, demographic data, treatment algorithms, implant material, implant dimensions, porosity, and manufacturing method. In some embodiments, the configuration parameters include implant material and device porosity based on the patient's anatomy and surgical treatment. In some embodiments, the porosity is selected. In some embodiments, the device configuration parameters are patient-specific. In some embodiments, the device configuration parameters are based on a general configuration and are not patient-specific.

[0107] For example, digital renderings or data of a device are generated for display from a graphical user interface or for storage on a database attached to the computer and processor. In some embodiments, the computer displays, via a monitor, saves, digitally manipulates, or prints a hard copy of the digital rendering or data. In some embodiments, the device is virtually designed using a CAD / CAM program on the computer display. In some embodiments, the processor executes code stored on a computer-readable storage medium to execute one or more computer instructions, for example, to send instructions to an additive manufacturing device. In some embodiments, the database or computer-readable medium comprises RAM, ROM, EPROM, magnetic, optical, digital, electromagnetic, flash drive, semiconductor technology, or a combination thereof. In some embodiments, the processor commands motors to control the movement and rotation of device components.

[0108] regenerative medicine "Regenerative medicine" refers to a branch of translational research in tissue engineering and molecular biology that deals with replacing, manipulating, or regenerating human cells, tissues, or organs to restore or establish normal function. This field promises to engineer damaged tissues and organs by stimulating the patient's internal repair mechanisms to functionally heal previously irreparable tissues or organs. For example, during bone regeneration, new bone formation is primarily influenced by physicochemical cues in the surrounding microenvironment. Tissue cells reside in the physiological microenvironment of a complex scaffold.

[0109] In some embodiments, tissue engineering is incorporated with the scaffolds or devices disclosed herein. Autograft incorporation occurs in five stages: inflammation, angiogenesis, osteoinduction, osteoconduction, and remodeling.

[0110] The inflammation lasts for approximately 7 to 14 days. Initial injury to the local blood supply and denudation results in a hematoma around the bone graft, into which inflammatory cells invade. Fibroblast-like cells in the inflamed tissue transform into a fibrovascular stroma.

[0111] Perioperative anti-inflammatory drugs decrease the rate of healing due to the inflammatory process.

[0112] Vascular sprouts appear in the fibrovascular stroma, similar to scar tissue formation during angiogenesis. Primary membranous bone forms adjacent to the denuded bone. Minimal cartilage and endochondral ossification then occur.

[0113] During osteoinduction (weeks 4-5), repair involves increased angiogenesis, necrotic tissue resorption, and osteoblastic and chondroblastic differentiation. In particular, stem cells differentiate into osteoblasts. New bone extends toward the central zone of the fusion mass. The cortical portion of the implant continues to resorb.

[0114] Osteoconduction is characterized by ingrowth and creep replacement into host bone. Osteoblasts form new bone, while osteoclasts simultaneously resorb the implant bone. A central zone of the endochondral interface is observed in the center of the fusion mass, connecting the inferior and superior halves of the fusion. Multipotent cells in this central zone differentiate into cartilage tissue with little vascularization.

[0115] During remodeling between weeks 6 and 10, a peripheral cortical rim forms around the fusion. Bone marrow activity increases, forming secondary cancellous bone. The cortical rim thickens. Trabecular bone processes extend to the center of the fusion. Remodeling is typically complete one year after device implantation.

[0116] Nonunion (pseudarthrosis) is a major cause of postoperative pain and accounts for 45% to 56% of revision arthroplasties. Bone union directly correlates with successful clinical outcome. Patients with pseudarthrosis were asymptomatic in approximately 30% of cases. Younger patients had a significantly increased rate of symptomatic nonunion (43.8 vs. 52.1 years, p<0.01).

[0117] In some embodiments, bone marrow aspirate (BMA) with allograft substitutes for autogenous bone graft in single-level revision posterolateral lumbar fusion (PLF). In some embodiments, bone marrow aspirate with allograft is more cost-effective than recombinant human bone morphogenetic protein-2 (rhBMP). In some embodiments, allografts enriched with bone marrow-derived cells are compared to autogenous grafts in bone graft and spinal fusion procedures. In some embodiments, BMA increases the regenerative capacity of corticocancellous allogeneic bone grafts. When treating unicameral bone cysts, the cure rate was high (98.7%) for bone marrow with demineralized bone matrix injection.

[0118] When introducing elements of the disclosure or embodiments thereof, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0119] Having described the present disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of the present disclosure as defined in the appended claims.

[0120] The disclosure described herein is susceptible to various modifications and alternative iterations, several embodiments of which are described in more detail above. However, it should be understood that the detailed description of the compositions is not intended to limit the disclosure to the several disclosed embodiments. Rather, it should be understood that the disclosure is intended to encompass all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the language of the claims. [Example]

[0121] The following examples are included to demonstrate some embodiments of the present disclosure. It should be understood by those skilled in the art that the techniques disclosed in the examples represent techniques discovered by the inventors to work well in the practice of the present disclosure. However, those skilled in the art should understand in light of the present disclosure that many changes can be made in some of the disclosed embodiments and still obtain the same or similar results without departing from the spirit and scope of the present disclosure. Accordingly, all matters should be interpreted as illustrative and not limiting.

[0122] [Table 1]

[0123] Example 1 - Pedicle Screw 2-4, pedicle screw 200 was 3D printed from titanium. Pedicle screw 200 included threads 230 disposed around a shaft 240 extending between a proximal end 210 and a distal tip 220. Thread 230 included an external thread form having a leading edge 231 with a leading surface 235 and a trailing edge 232 with a trailing surface 236. Leading surface 235 defined a first opening 251. Trailing surface 236 defined a second opening 252. The first and second openings 251, 252 were axially aligned.

[0124] The pedicle screw 200 had a core 260 that extended through the center of the pedicle screw 200 from the proximal end 210 to the distal tip 220. The distal tip 220 was provided with two cutting members 270, each having a cutting edge 271.

[0125] 5-7, an embodiment of a pedicle screw 300 was 3D printed in titanium using the scaffolding 280 disclosed herein. The pedicle screw 300 included threads 230 disposed about a shaft 240 extending between a proximal end 210 and a distal tip 220. The shaft 240 included two regions of scaffolding 280 exposed on the outer surface of the pedicle screw 300. The threads 230 included an external thread form having a leading edge 231 with a leading surface 235 and a trailing edge 232 with a trailing surface 236. The leading surface 235 defined a first opening 251. The trailing surface 236 defined a second opening 252. The first and second openings 251, 252 were axially aligned. The pedicle screw 300 had a core 260 filled with a scaffold 280 that extended through the center of the pedicle screw 300 from the proximal end 210 to the distal tip 220. The distal tip 220 was provided with three cutting members 270, each having a cutting edge 271.

[0126] 8-10, another embodiment of a pedicle screw 400 was 3D printed in titanium using the scaffold 280 disclosed herein. The pedicle screw 400 included threads 230 disposed about a shaft 240 extending between a proximal end 210 and a distal tip 220. The shaft 240 included a region of scaffold 280 exposed on the outer surface of the pedicle screw 400 between the central seven turns of the threads 230. The threads 230 included an external thread form having a leading edge 231 with a leading surface 235 and a trailing edge 232 with a trailing surface 236. The leading surface 235 defined a first opening 251. The trailing surface 236 defined a second opening 252. The first and second openings 251, 252 were axially aligned. The pedicle screw 400 had a core 260 filled with a scaffold 280 that extended through the center of the pedicle screw 400 from the proximal end 210 to the distal tip 220. The distal tip 220 was provided with three cutting members 270, each having a cutting edge 271.

[0127] 11-16 , another embodiment of a pedicle screw 500 was 3D printed in metal using the scaffold 280 disclosed herein. The pedicle screw 500 comprises a cap 510, a saddle 520, and a shaft 540, and, if present, a tulip 590 and a pair of pins 595. The cap 510 is configured to couple to the saddle 520 via cap threads 513 operably disposed within the saddle groove 523. The saddle 520 is configured to couple to the shaft 540. In the pedicle screw embodiment having a tulip, the distal tip 220 of the shaft 540 may be positioned through a bottom opening 592 of the tulip 590 and held in place with a pin 595 positioned through a side opening 596 of the tulip 590.

[0128] The pedicle screw 500 included threads 230 disposed around a shaft 240 extending between a proximal end 210 and a distal tip 220. The shaft 240 included a region of scaffolding 280 exposed on the outer surface of the pedicle screw 500 between the central 13 turns of the threads 230. The threads 230 included an external thread form having a leading edge with a front surface and a trailing edge with a rear surface. The pedicle screw 500 had a core filled with scaffolding 280 extending through the center of the pedicle screw 500 from the proximal end 210 to the distal tip 220. The distal tip 220 included a cutting member 270.

[0129] 13 and 14, the cap 510 comprises a cap body 514 having a cap thread 513 helically disposed around the outer surface of the cap body 514 between a cap top 511 and a cap bottom 512.

[0130] 15 , saddle 520 includes a saddle top 521, a saddle bottom 522, and a saddle body 524 having at least one saddle groove 523 disposed on an inner surface of saddle body 524. At least one saddle groove 523 is configured to receive and operably couple with cap threads 513. Similarly, saddle bottom 522 is configured to receive and operably couple with proximal end 210 of shaft 540.

[0131] 16 , when present, tulip 590 comprises tulip body 594 having a top opening 591, a bottom opening 592, at least one pair of tulip grooves 593 disposed on an inner surface of tulip body 594, and a pair of side openings 596 between at least one pair of tulip grooves 593 and bottom opening 592. At least one pair of tulip grooves 593 are configured to receive and operably couple with threads 230 of shaft 540 when distal tip 220 of shaft 540 passes through bottom opening 592 of tulip 590.

[0132] After the threads 230 engage at least one pair of tulip grooves 593 , a pair of pins 595 can be operably coupled to the tulip 590 through a pair of side openings 596 .

[0133] When present, the pores in the scaffold 280 promoted bone ingrowth through the screw. Other materials for fabricating the pedicle screws included pre-packed demineralized bone matrix (DBM), pre-packed synthetic DBM, unpacked DBM, and magnesium-infused titanium. A built-in channel captured the autograft during insertion. The screw had dual ball angulation and a low profile. The screw was equipped with a locking cap with reverse-angle threads. The screw could be cannulated or non-cannulated.

[0134] The screws were 35 mm to 65 mm in length and 4.5 mm to 8.5 mm in diameter. The rod acceptance was 5.5 mm.

[0135] The built-in channels for autograft collection enhanced the structural integrity of the implant. They provided excellent resistance to bone mineral density loss and reduced micromotion. The randomized porosity pattern 280 of the scaffold was typical of natural trabecular bone. Additionally, the built-in struts provided structural integrity. The pedicle screws 200, 300, 400, and 500 were fabricated from cobalt chromium, titanium, and magnesium-infused titanium.

[0136] The device was tested in cobalt chrome and met American Society for Testing and Materials (ASTM) standards 543, 1798, and 1717.

[0137] ASTM Standard 543 evaluates the chemical resistance of plastic materials, including cast, thermoformed, cold-formed, laminated resin products, and sheet materials. Three procedures are presented: two immersion tests and one test, called Test B, which is mechanical stress and reagent exposure under standardized conditions of applied strain. These tests report changes in weight, dimensions, appearance, color, strength, and other mechanical properties. Standard reagents are specified to establish comparable results without excluding other chemical reagents related to specific chemical resistance requirements. Provisions are made for exposure to the reagents at various exposure times, stress conditions, and elevated temperatures. The type of conditioning (immersion or wet patch / wipe method) depends on the end use of the material.

[0138] ASTM Standard 1798 covers the measurement of uniaxial static fatigue strength and resistance to loosening of component interconnection systems in spinal fusion implants. This test method provides a means to mechanically characterize different interconnection designs for spinal implants. Various components and interconnections can be combined for static and fatigue testing of spinal implant constructs. This test method does not address the analysis of spinal implant constructs or subconstructs, nor does it define performance levels for spinal implants.

[0139] ASTM Standard 1717 covers materials and methods for static and fatigue testing of spinal implant assemblies in vertebrectomy models. Test materials for combinations of spinal implant components can be specific, depending on the spinal location and intended method of application to the spine. These test methods provide a basis for mechanical comparison between past, current, and future spinal implant assemblies. They allow for the comparison of spinal implant constructs with different intended spinal locations and methods of application to the spine. These test methods are not intended to define levels of performance. Instead, they set guidelines for load types and methods for applying loads, measuring displacement, determining yield loads, and evaluating the stiffness and strength of spinal implant assemblies. Three static load types and one fatigue test method are defined for the comparative evaluation of spinal implant assemblies.

[0140] In some embodiments, the pedicle screws 200, 300, 400, 500 are individually packaged in double Tyvek™ stripping trays.

[0141] In some embodiments, the pedicle screws 200, 300, 400, 500 are injected or sprayed with materials such as BMA concentrate, calcium phosphate, biologics, and / or antibiotics, and the filled or coated screws are allowed to rest for 10-15 minutes before insertion to allow the material to absorb.

[0142] Example 3 - Bone Harvesting Screw Referring to Figure 17, bone harvesting features (scoops) are located on the smaller diameter of the screw. These draw bone and tissue into the lattice structure as the screw is inserted.

[0143] In some embodiments, the bone harvesting features are located along the entire length of the screw.

[0144] In some embodiments, bone-harvesting features are located only along the distal portion of the screw (FIG. 19). Section AA shows bone-harvesting features at the leading edge of each opening, so that during insertion, the bone-harvesting features draw cells into the porous (lattice) structure of the screw (FIG. 20). In this embodiment, the proximal portion does not have these features (FIG. 18), allowing for a tight fit within the cortical bone located at the proximal end of the screw. Section BB shows the area without bone-harvesting features (FIG. 21).

[0145] In some embodiments, the scoop feature slopes from a small diameter to a slightly larger diameter on the surface between the porous structures, hi such embodiments, the scoop feature is biased in the insertion direction.

[0146] In some embodiments, the scoop feature is angled or has a radius to aid in collection, hi some embodiments, the leading edge is angled.

[0147] In some embodiments, the screw includes a thickened head-neck junction below the opening, for example, to reduce the chance of the rod breaking during installation of the screw.

[0148] Example 3 - Diamond Lattice Structure Bone screws were 3D printed and tested with a diamond lattice structure. In some embodiments, the scoop features are located along a spiral pattern that corresponds, for example, to the spiral pattern of openings to the internal lattice structure.

[0149] The design is based on a triply periodic minimal surface (TPMS), which is invariant under rank-3 translational lattices. 3 These surfaces have the symmetry of a crystallographic group. Numerous examples are known with cubic, tetragonal, rhombohedral, and orthorhombic symmetries.

[0150] Specifically, a Schwarz diamond TPMS was used for the lattice, formed from symmetry arguments, and remapped from Cartesian coordinates to spherical polar coordinates around the central axis of the screw shaft, which was sheared, thickened, and subtracted to form a helical wrap and intersected with the 3D geometric shape space of the scaffold.

[0151] The surfaces were generated using symmetry arguments. Given a solution to Plateau's problem for a polygon, a reflection of the surface across the boundary line also generates a valid minimal surface that can be continuously joined to the original solution. If the minimal surface intersects the plane at a right angle, its mirror image in the plane can also be joined to the surface. Thus, given a suitable initial polygon inscribed in the unit cell, a periodic surface can be constructed.

[0152] Equation 1 approximates the TPMS of these bone screws. cos(x)cos(y)cos(z)-sin(x)sin(y)sin(z)=0 (1) This is the specific fundamental equation for this embodiment of the bone screw. The x, y, and z variables define the periodicity (i.e., pattern) in X / Y / Z, similar to how a cubic lattice is defined. This surface is called a "diamond" because it has two intertwined congruent labyrinths, each with the shape of an expanded tubular version of a diamond-bonded structure. For purposes of illustration, we have assumed regularly repeating cells, but the geometry of the TPMS is influenced in a topologically pseudo-random manner. Exact equations exist for elliptic integrals based on the Weierstrass-Ennepar parameterization.

[0153] As an equation, this defines a Schwartzian D-plane through infinite real space. Such a plane divides real space into two identical volumes, with positive space entering negative space, defining an isosurface or midsurface. Figure 22 shows a two-dimensional slice through the Schwartzian diamond mathematical field, where the Teal space is "positive" and the Purple space is "negative." Figure 23 shows a three-dimensional cross section of the unthickened surface of Figure 22, where light gray represents the positive side of the surface and dark gray represents the negative side, as defined by the surface normal vector. In some embodiments, the repeating cubic pattern is 1.8 mm in X / Y / Z.

[0154] After developing the Schwartz equation, it was remapped spirally (i.e., twisted) to create the basis for the final shape. To do this, the equation was mapped from Cartesian space to polar space using conventional methods. The periodicity was mapped cylindrically; that is, the number of "spokes" remained a multiple of the selected cell size in the radial direction. Figure 24 shows the cylindrical remapping after transformation to polar space. The remapping was about the central axis of the screw shaft.

[0155] After remapping, the space was sheared to create a helical wrapping, similar to how a screw is created by wrapping an inclined plane around a cylinder. To generate the shear, the Schwartz D equation was remapped from the X / Y / Z coordinate space by shearing one (or more) coordinates: x → x, y → y, z → where the Schwartz diamond was sheared in the XZ plane. Such shearing operations maintained a continuous field.

[0156] After shearing the field and remapping it cylindrically, an absolute value operation was used to thicken it, thereby converting the negative space of the equation to positive in three dimensions (Figure 25). The helical wrapping of the medical device was defined with a period (5.4 mm) three times the size of the cubic repeating pattern, forming a single helix with three circumferential counts for three radial spokes. A subtraction mathematical operation then offset the central geometry to create a sheet-like structure, as seen in Figure 26, where the thin-walled geometry is represented by pale pink walls radiating out cylindrically. In some embodiments, the walls are approximately 0.50 mm thick. When the thin-walled lattice field was intersected with the 3D geometric space that defines where the lattice resides, a model of the scaffold was generated (Figure 29).

[0157] The diamond lattice described above was fabricated for two embodiments of bone screws. Figure 30 shows a perspective view of one embodiment of a porous pedicle screw exhibiting such a spiral pattern in a diamond structural lattice. Figure 31 shows the rear surface of the porous pedicle screw, Figure 32 shows the front surface, Figure 34 shows the top surface, and Figure 35 shows the bottom surface. Figure 33 shows an enlarged inset of the front view of the porous pedicle screw.

[0158] Figure 36 shows a perspective view of another embodiment of a porous pedicle screw presenting a diamond lattice structure with bone-harvesting features at the distal tip and textured threads at the proximal end. This texture resembles the surface topography of a diamond lattice structure. Figure 37 shows the rear surface of the porous pedicle screw, Figure 38 shows the front surface, Figure 40 shows the top surface, and Figure 41f shows the bottom surface. Figure 39 shows an enlarged inset of the front view of the porous pedicle screw.

[0159] Example 4 - Ovine studies of bone integration and pull-out strength In vivo evaluation, ex vivo evaluation, and data from this six sheep study will determine how this treatment modality affects bone mineral density, polymorphonuclear cells (PMNs), lymphocytes, plasma cells, macrophages (Mφ), giant cells, necrosis, osteoblasts, signs of bone remodeling by osteoclasts, angiogenesis, fibrosis, signs of implant degradation, and particulate debris.

[0160] The first specific objective was to determine whether porous pedicle screws promote bone integration and pullout strength compared to gold-standard pedicle screw / rod constructs in a posterior lumbar interbody fusion sheep model. The 3D-printed porous pattern topography has been shown to promote higher stem cell adhesion to titanium. Furthermore, mesenchymal stem cells and hematopoietic stem cells have therapeutic effects on bone. By combining these two modalities, the disclosed porous pedicle screws can achieve superior bone integration and pullout strength results compared to current pedicle screws.

[0161] To this end, bone mineral density (BMD) of 84 vertebral bodies (L1-L6) was measured from six sheep 1 week preoperatively and 24 and 36 weeks postoperatively. Each subject underwent two separate lumbar interbody fusions (LIFs) at the L2-L3 and L4-L5 joints. L1 and L6 served as naive controls to compare changes with and without hardware.

[0162] [Table 2]

[0163] In each subject, a titanium interbody cage and bone void filler packed into the cage were placed between the L2-L3 and L4-L5 segments. Screws with diameters of 4.5, 5.5, or 6.5 mm and lengths of 45±10 mm were then inserted into the right and left pedicles of the L2, L3, L4, and L5 vertebral bodies. This configuration represents a conventional fixation device and surgical technique. Prior to insertion, the porous pedicle screws (treatment) were sprayed with autologous stem cell concentrate along the length of the porous pedicle screws.

[0164] In-life radiographs of the lumbar spine are performed on all animals immediately post-operatively (PO) and at the time of sacrifice. Animals are visually evaluated at least once daily throughout the study. Abnormalities, such as signs of infection at the surgical site, are recorded. A total of six animals are sacrificed 36 weeks after surgery.

[0165] After euthanasia, lumbar segments (L1-L5) are freshly dissected into single functional spinal units (FSUs), i.e., L4-L5, for post-sacrifice evaluation. High-resolution biplanar digital radiographs and photographs are taken at the time of sacrifice after fine dissection in the sagittal and coronal planes. Non-fracturing range of motion (ROM) biomechanics are measured in all specimens, including ROM biomechanics under pure moment loading in flexion-extension, lateral bending, and axial rotation up to 6.0 Nm, yielding range of motion (degrees), construct stiffness (degrees / Nm), and neutral zone (degrees).

[0166] Destructive pedicle screw pull-out tests. Quasi-static ramp to failure tests yield construct stiffness (N / mm), yield force (N), ultimate failure force (N), and visually observed failure mode (MOD). Destructive pedicle screw torque-out tests are performed for N=1 of four screws from each, and counterclockwise quasi-static torque to loosen the screws yields the ultimate torque (Nm).

[0167] Other tests included micro-computed tomography (MicroCT) of each FSU and associated pedicle screw, quantitative assessment of the posterior lumbar fusion (PLF) area (bone volume and bone density), qualitative assessment of bone ingrowth around the pedicle screws, pedicle screw histology, organ histology, and static histomorphometry of the screw region of interest (ROI), including the percentage of bone area within the ROI, the percentage of fibrous tissue within the ROI, the percentage of void space within the ROI, the percentage of screws within the ROI, and the percentage of bone ingrowth into the device.

[0168] Slides are sent to a certified pathologist for histopathological analysis. The pathologist is initially blinded to the treatment parameters for each site. Sections are then analyzed and graded by cell type and response, if applicable, according to the grading scheme in Table 3. After scoring all slides for data post-processing, the pathologist is unblinded so that the data can be compared to control samples.

[0169] [Table 3]

[0170] The histopathology report will include, but is not limited to, a summary of methods and materials, tabulated qualitative data throughout the final time points and conclusions, low-magnification images, and representative photomicrographs to illustrate findings. Unpaired t-tests with an alpha (α) value of 0.05 will be performed to determine statistical significance for biomechanical and histomorphometric outcome parameters. Data will then be compared to similar retrospective studies.

[0171] The second specific objective of this study is to demonstrate the safety of injecting and spraying autologous concentrated stem cells into and around pedicle screws. Porous 3D-printed titanium interbody cages are commonly impregnated with autologous stem cells during surgery. They have been proven safe and are the gold standard for aiding fusion between vertebrae after disc removal. This study aims to demonstrate that the same can be done in sheep vertebrae to provide safety confidence for human clinical trials.

[0172] After sacrifice, histology will be compared with previous studies to determine differences and similarities in polymorphonuclear cells (PMNs), lymphocytes, plasma cells, macrophages (Mφ), giant cells, necrosis, osteoblasts, signs of bone remodeling by osteoclasts, angiogenesis, fibrosis, signs of implant degradation, and particulate debris. Histological reports will also be compared and contrasted between control, naive, and treatment sites. Unpaired t-tests with an alpha (α) value of 0.05 will be performed to determine statistical significance for biomechanical and histomorphometric outcome parameters. Injecting autologous stem cells into and around porous pedicle screws is expected to be safe compared to control screws, naive screws, and previous studies.

[0173] The third specific objective of this study was to demonstrate that porous pedicle screws have a topography and porous pattern that promote stem cell adhesion. Human mesenchymal stem cells have the strongest adhesion affinity, a more robust and dense internal cell migration pattern, and high cell viability for titanium surfaces with porosity between 50% and 70%. Therefore, the porous pattern and topography of porous pedicle screws should have similar adhesion properties for stem cells.

[0174] After slaughtering the sheep, the screws are removed from the vertebrae and stem cell adhesion is studied. Cell viability on the implant surface is measured using a live / dead assay. Conditioned medium assays are used to study bone morphogenetic protein 2 (BMP2) expression levels, vascular endothelial growth factor (VEGF), osteocalcin, osteoprotegerin expression, DNA, and alkaline phosphatase activity.

[0175] A correlation between cell adhesion to 3D-printed titanium patterns and porous pedicle screws is shown. Porous pedicle screws exhibit better stem cell adhesion than control and naive subjects, and adhesion rates similar to previous studies.

[0176] Example 5 - Sheep studies on infection Another six animal studies will focus on testing the feasibility of injecting calcium sulfate with an antibiotic mixture as a means of reducing infection rates after spinal fusion. The primary objectives of this project are to (1) determine whether the tested pedicle screws support superior bone integration and pullout strength compared to the gold-standard pedicle screw / rod construct in a posterior lumbar interbody fusion sheep model. (2) Injecting calcium sulfate with an antibiotic mixture can reduce infection rates after spinal fusion, and (3) the tested pedicle screws have a topography and porous pattern to support the above-mentioned goal of injection.

[0177] For the first objective, the rationale is that if a patient has infected bone, the surgeon can protect the hardware by injecting an antibiotic mixture through the device. Through the proposed animal studies, we will confirm that in infected and contained areas (e.g., vertebrae), pedicle screws (1) protect the surgical hardware (i.e., confirm that the infection has not spread to the hardware) compared to controls, and (2) reduce infection in the bone.

[0178] The sheep model was chosen because it has a vertebral column that is most similar to the human spine. The sheep vertebrae are large enough to accommodate the pedicle screws disclosed herein. Smaller animals would not survive due to the screws being too large for their bones.

[0179] This sample size was selected to realistically assess feasibility and achieve proof of concept within the scope and timeline of Phase I. In alignment with program objectives, Phase I results will be interpreted as preliminary, and tentative conclusions will be used to inform an anticipated Phase II, where we propose a large-scale, controlled, and adequately powered animal study that will evaluate efficacy endpoints in a scientifically rigorous manner.

[0180] The experimental design and methods were essentially the same as those for the sheep study described above in Example 4, including Tables 2 and 3.

[0181] All references, patents, or applications (U.S. or foreign) cited in this application are hereby incorporated by reference as if set forth in their entirety herein. In the event of a conflict, the material disclosed herein will control.

[0182] From the foregoing description, those skilled in the art can easily ascertain the essential features of the present invention, and can make various changes and modifications to the present invention to adapt it to various uses and conditions without departing from the spirit and scope of the present invention.

Claims

1. A medical device comprising: The main body and a scaffold within the body; and means disposed on the body for concentrating bone growth throughout the body to minimize shear stress on the distal tip and distribute micro-motion throughout the medical device to promote bone ingrowth.

2. 10. The medical device of claim 1, wherein the means for concentrating bone growth comprises at least one trephine for harvesting bone internally within the medical device.

3. 3. The medical device of claim 1 or 2, configured with an arcuate cross-sectional pattern that varies from the proximal end to the distal tip.

4. 4. The medical device of claim 3, configured for placement within an internal cavity of a vertebral body such that autograft is harvested within the scaffold upon coaxial rotation of the medical device.

5. The medical device of any one of claims 1 to 4, wherein the threads have a concave profile.

6. 10. The medical device of claim 1 or 5, wherein the scaffold comprises a triple period minimal surface (TPMS) having a repeating pattern of cubes that define walls within the scaffold.

7. 7. The medical device of claim 6, wherein the TPMS is a Schwarz diamond spirally wrapped around a central axis of the medical device and within the 3D geometric space for the scaffold.

8. The medical device of claim 7 , wherein the TPMS is helically wound in a single helix.

9. 9. The medical device of claim 7 or 8, having three radial spokes per turn of the spiral.

10. The medical device of any one of claims 6 to 9, wherein the repeating cubic pattern has X / Y / Z dimensions of approximately 1.8 mm.

11. The medical device of any one of claims 7 to 10, wherein the spiral wrapping of the medical device is defined with a period three times the size of the cubic repeating pattern.

12. The medical device of any one of claims 6 to 11, wherein the wall is about 0.5 mm thick.

13. The medical device of any one of claims 1 to 12, wherein the threads near the proximal end are textured with a topography similar to that of the scaffold.

14. The medical device of any one of claims 1 to 13, configured to house one or more biological agents.

15. The medical device of any one of claims 1 to 14, further comprising at least one homemade product that is sprayed onto or injected through the medical device.

16. The medical device of any one of claims 1 to 15, wherein the body is a shaft.

17. 17. The medical device of claim 16, which is a bone screw.

18. 18. The medical device of claim 17, wherein one or more of screw loosening, screw backout, rod breakage, and bone mineral density loss are reduced.

19. 19. The medical device of claim 17 or 18, comprising a fluted tip.

20. The medical device of any one of claims 17 to 19, which is a pedicle screw.

21. A method of treating a bone fracture in a patient in need thereof, comprising implanting a medical device according to any one of claims 1 to 20 into the bone of said patient.

Images