Device with lumen for bone implant - Patent application

Abstract

Provided herein are medical devices and methods for treating bone fractures. The medical device includes a body having a proximal end and a distal tip, and houses a scaffold having a porous structure distributed in proximal and distal lattices. The device includes an upper lumen in fluid communication with a first opening at the proximal end and a lower lumen in fluid communication with a second opening at the proximal end. The device is configured to support independent delivery of cement and cells to the lattice. In some embodiments, the device is a bone screw with a thickened head-neck joint designed to reduce the likelihood of rod breakage during installation. The method includes implanting the device into a patient's bone, providing an innovative approach to bone fracture treatment.

Description

[Technical Field]

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 422,638, filed November 4, 2022, 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 techniques use bone grafts and hardware, such as pedicle screws, to encourage the 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 surgery is high, approximately 10-46%.

[0005] A review of spinal fusion surgeries 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, advances in lumbar interbody fusion (LIF) techniques have been made possible by computer navigation, augmented reality, minimally invasive surgical (MIS) approaches, disc arthroplasty, bone-stimulating pedicle screws, and bone cavity filler options. Nevertheless, due to an increasing patient population and high failure rates, the number of patients developing lumbar postoperative pain syndrome (FBSS) continues to increase. (FBSS occurs when the results of lumbar spine surgery do not meet the patient's and surgeon's preoperative expectations.)

[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-shaped heads of the pedicle screws to stabilize the construct until fusion is achieved. However, since 1975, few technological advances have been made in spinal stabilization systems, and these constructs do not address important long-term stability issues related to bone mineral density quality and patient health. Hardware used in lumbar fusions is subject to significant forces that can cause hardware failure 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 pullout. This loosening due to lack of fusion can endanger nerves or blood vessels and often requires hardware removal and repeat surgery.

[0008] Unfortunately, spinal revision surgery also has a low success rate. Second revision cases have a 30% success rate, third surgery 15%, and fourth surgical intervention 5%. Furthermore, adult spinal deformity patients who have endured two or more previous revisions exhibit more coronal and sagittal imbalances and poorer 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. 21 The estimated total direct and indirect costs attributable to SSIs range from $1 billion to $10 billion annually. Spinal instrumented surgery poses a greater risk of SSI and results 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 spinal instrumented surgery results 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 a medical device is implanted, regardless of the material used. This loss is a common cause of medical device failure, including screw loosening, screw backout, and rod breakage. While many devices promote fusion within interbody cages, none have been developed to provide scaffolding and increase 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 surgery: 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 having a proximal end and a distal tip. The device includes a scaffold in the body, the scaffold having a porous structure distributed in a proximal lattice in a first zone near the proximal end and a distal lattice in a second zone near the distal tip. The device also has an upper lumen at the proximal end in fluid communication with the first opening at the proximal end and a lower lumen at the distal tip in fluid communication with the second opening at the proximal end.

[0013] In another aspect, the present disclosure provides a medical method for treating a bone fracture in a patient in need thereof, the method comprising implanting a device as described above in a bone of the patient.

[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 particular 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] 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] 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] 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] 1 shows a screw containing two regions of a discrete internal porous lattice structure. The dual lumen allows for delivery of cells to the proximal lattice and cement to the distal lattice. [Figure 18] FIG. 18 is an inset of the screw of FIG. 17 showing the lower lumen communicating from the head of the screw with the proximal porous (lattice) structure. [Figure 19] FIG. 10 is a top perspective view of the proximal end of the screw showing the split feature that divides the aperture into dual lumens.

[0016] The disclosure will be readily understood from the following detailed description in conjunction with the accompanying drawings, in which reference numerals designate 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 having a proximal end and a distal tip. The device includes a scaffold in the body, the scaffold having a porous structure distributed in a proximal lattice in a first zone near the proximal end and a distal lattice in a second zone near the distal tip. The device also has an upper lumen at the proximal end in fluid communication with the first opening at the proximal end and a lower lumen at the distal tip in fluid communication with the second opening at the proximal end.

[0018] In some embodiments, the medical device further comprises a fenestration at the distal tip.

[0019] In certain embodiments, the medical device is configured to support independent delivery of cement deployed through the fenestrations. In some embodiments, the porous structure of the medical device supports cells incorporated in the center of the medical device. In certain embodiments, the medical device is configured to allow delivery of cells to the proximal lattice and delivery of cement to the distal lattice.

[0020] In some embodiments, the proximal lattice, the distal lattice, or both of the medical device comprise a discrete internal porous lattice structure. In certain embodiments, the upper lumen of the medical device contacts the cortical bone and the lower lumen contacts the cancellous bone. In some embodiments, the medical device further comprises a dividing feature configured to divide the upper and lower lumens. In certain embodiments, the medical device further comprises at least one additional lumen.

[0021] In some embodiments, the medical device is a bone screw having a head at the proximal end. In some embodiments, the bone screw is a pedicle screw. In some embodiments, an upper lumen of the bone screw communicates from the head of the bone screw to a distal lattice, and a lower lumen communicates from the head of the bone screw to a proximal lattice. In some embodiments, the bone screw comprises a thickened head-neck joint below the first opening and the second opening. In some embodiments, the bone screw is configured to reduce the likelihood of rod breakage during installation of the screw.

[0022] In one embodiment, a medical method for treating a bone fracture in a patient in need thereof comprises implanting the medical device of any of the previous embodiments into the patient's bone. scaffold

[0023] Surface curvature and Minkowski bone morphology curvature maps (functions that restore the concept of distance in linear space) show a significantly different porous matrix in the trabecular bone within the vertebrae relative to other areas 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.

[0024] The porous 3D printed scaffold promotes osseointegration, fusion, and fixation within the bone. The open framework with 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.

[0025] 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.

[0026] In certain embodiments, the disclosed scaffolds and devices integrate orthopedic products with tissue engineering, preventing the risk of delayed bone integration to implanted devices.

[0027] 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 mechanical strength, cell retention, and cell migration. Particle size cues signal protein absorption, cell adhesion, cell proliferation, and cell adhesion. Surface topography cues 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. bone

[0028] 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 framework is organized into a three-dimensional lattice of bony protrusions 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.

[0029] Cancellous bone makes up about 20% of the human skeleton and provides structural support and flexibility without compact bone. It is found in most areas 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.

[0030] 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 site, density, and age. Mechanical factors, including elastic modulus, uniaxial strength, and fatigue properties, are also investigated.

[0031] 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 reduces the strength of bone, but it can also reduce its weight.

[0032] Porosity and structure affect the strength of a material. Therefore, the microstructure of trabecular bone is typically oriented. The mechanical stiffness and strength are greatest when the porous "grains" are aligned. 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 fracture strength is 1-100 MPa.

[0033] "Cortical bone" or "compact bone" is much denser than cancellous bone. It forms the hard exterior (cortex) of bone. Cortical bone gives bones their smooth, white, and hard appearance. It accounts for approximately 80% of the total bone mass in the human skeleton. Trabecular bone is usually surrounded by a shell of compact bone, which provides greater strength and rigidity. The open structure of cancellous bone allows it to attenuate sudden stresses, such as load transmission through joints. Varying ratios of air space to bone are found in different bones, depending on the need for strength or flexibility. Trabecular bone also has a relatively high level of metabolic activity.

[0034] "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. vertebrae

[0035] Each vertebra is an irregular bone in the vertebrate spinal column with a complex structure consisting of bone and some hyaline cartilage, the proportions of which vary according to the segment of the spine and the vertebrate species.

[0036] The basic structure of vertebrae varies. The majority of the vertebra is the vertebral body, with a hollow central section. The superior and inferior surfaces of the vertebral body provide attachment for the intervertebral discs. The posterior section forms the vertebral arch with 11 sections consisting of two pedicles, two laminae, and seven processes. The laminae provide attachment for the ligamentum flavum (ligaments of the spine). There are vertebral notches formed from the shape of the pedicles, which form the intervertebral foramina when the vertebrae articulate. These foramina are the entrance and exit canals for the 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.

[0037] 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 from each side, one at the junction of the posterior lateral surface of the hollow space to its superior surface. From each pedicle, broad plates called "lamina" project posteriorly and medially to join and complete the vertebral arch, forming 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 depressions called vertebral notches (superior and inferior). When the vertebrae articulate, the notches align with those of the adjacent vertebra, forming the intervertebral foraminal openings. The foramina allow spinal nerves and associated blood vessels to enter and exit each vertebra. The articulating vertebrae provide strong support for the body. Device

[0038] The present disclosure provides a device formed from the scaffolds disclosed herein. In some embodiments, the device is cannulated and fenestrated with the scaffold. In some embodiments, the device comprises a threaded distal region, optionally a threaded central region, and optionally a threaded proximal region, in response to a compressive force.

[0039] In certain embodiments, the device is selected from pedicle screws, cannulated pedicle screws, fenestrated pedicle screws, capitellar screws, capitellar screws, headless screws, traumatic hip fracture devices, glenoid cages, screws for glenoid cages, trauma plates, tibial stems, femoral stems, hammertoe implants, nail fusion systems, Charcot foot deformity correction, radial head fracture devices, high tibial osteotomy, deformity correction, corpectomy cages, tumor correction, anchors, dental implants, maxillofacial implants, and sports medicine anchors.

[0040] In some embodiments, the device is selected from a hip fracture system, a reverse total shoulder prosthesis, a dental implant, upper extremity hardware, lower extremity hardware, a total joint replacement implant, a total joint revision implant, a spinal fusion, a spinal arthroplasty, a regenerative therapy, a cartilage implant, a maxillofacial hardware, and a cardiac implant.

[0041] In some embodiments, the screw is configured with features that facilitate bone growth through the structure of the screw from both sides, allowing bone to connect through the screw. In some embodiments, the features are narrow, such as through threads, thereby allowing rapid through-growth. In some embodiments, the features are deeper, such as through a small diameter, and therefore a stronger connection. In some embodiments, the features are voids or porous within the screw or structured to promote bone growth. In some embodiments, the features collect autograft material within channels inside the device. In some embodiments, the features are impregnated with one or more polymers.

[0042] 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, to pull it out of 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 backout. In some embodiments, the bone screw is designed to diffuse micromotion and reduce shear to enhance bone mineral density.

[0043] In some embodiments, the device includes a bone screw with bone-penetrating growth through the shaft of the screw to reduce screw toggling and potential failure. In some embodiments, the bone screw includes features that allow bone to grow through the structure of the bone screw from both sides, allowing bone to connect through those bone-penetrating structures. In some embodiments, the bone screw includes features that may be narrow, such as through the threads of the bone screw, which may allow for rapid bone-penetrating growth. In some embodiments, the bone screw includes features that may be deeper, such as a small diameter that 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 enter or exit from the same or adjacent surfaces. In some embodiments, the voids or cavities may contain scaffolding for bone attachment or porous structures on the surface of the void.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] "Administering a therapy" or "treating" a disease or condition refers to performing a procedure to alleviate the signs or symptoms of the disease or condition, which may include administering one or more drugs to a patient, using an implantable device, and / or using instruments to treat the disease, such as microdiscectomy instruments to remove bulging or herniated discs and / or bone spurs. Administering a therapy or treatment does not require complete relief or cure of signs or symptoms, and specifically includes procedures that have a minimal effect on the patient. For example, treatment may include inhibiting the disease, e.g., halting its progression, or palliating the disease, e.g., causing regression.

[0050] "Prophylaxis" refers to the alleviation of signs or symptoms of a disease or condition before they appear. Thus, prophylaxis includes preventing disease from occurring in patients who may be susceptible to the disease but have not yet been diagnosed with the disease.

[0051] "Tissue" includes soft tissue, ligament, tendon, cartilage, and / or bone. In certain embodiments, the tissue is cancellous bone, cortical bone, or corticocancellous bone.

[0052] In some embodiments, the device is used for other skeletal and bone-related applications, including diagnosis and treatment. In some embodiments, the device can alternatively be used for surgical procedures with the patient in prone or supine positions, and / or for various surgical approaches to the spine, including anterior, posterior, posteromedial, lateral, posterolateral, and / or anterior-lateral approaches, and other body regions, as well as other body regions, such as the maxillofacial and extremities. The device can also alternatively be used in 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-living substrates, for example, for training, testing, and demonstrations.

[0053] In some embodiments, the device is a custom medical device. In some embodiments, the device is adapted for sports medicine.

[0054] In some embodiments, the device is temperature sensitive. In some embodiments, the device is pH balancing.

[0055] In certain embodiments, devices are fabricated with porosity having porogens that are spheroidal, cubic, rectangular, elongated, tubular, fibrous, discoidal, platelet-like, polygonal, or mixtures thereof. In some embodiments, the porosity is based on a plurality of macropores, micropores, nanopore structures, and / or combinations thereof.

[0056] In some embodiments, the device is fabricated from biologically acceptable materials suitable for medical use, including metals, synthetic polymers, ceramics, and bone materials, and / or composites thereof, hi some embodiments, the device comprises one or more selected from metals, ceramics, rubber, hydrogels, rigid polymers, textiles, bone materials, and composites thereof.

[0057] 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 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 a tissue growth factor or differentiation factor. In some embodiments, the device comprises an absorbable material such as a composite of a metal and a calcium-based ceramic, a composite of PEEK and a calcium-based ceramic, a composite of PEEK and an absorbable polymer, a fully absorbable material such as a calcium-based ceramic, e.g., calcium phosphate, tricalcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate, or other absorbable polymers such as polyketides, polyglycolides, polytyrosine carbonate, polycaprolactone, and other combinations.

[0058] 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.

[0059] In one embodiment, 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 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.

[0060] 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 metals such as Gum Metal®. In some embodiments, the device comprises titanium. In some embodiments, the device comprises iron.

[0061] 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.

[0062] 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.

[0063] In some embodiments, the device is employed to treat diseased areas of a vertebra. A physician gains access to a surgical site containing the vertebra by any suitable method, such as dissection and retraction of tissue. In some embodiments, the device comprises a bone screw for augmenting 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.

[0064] In certain 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.

[0065] In certain 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 structure.

[0066] 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, parallel orientation within the wall. In some embodiments, the lattice comprises one or more layers of a material matrix.

[0067] 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.

[0068] In some embodiments, the lattice forms a rasp-like configuration. In some embodiments, the lattice is configured to engage tissue. In certain embodiments, engaging the lattice cuts, removes, shears, dissects, or breaks tissue. In some embodiments, the lattice comprises a configuration selected from cylindrical, circular, elliptical, oval, triangular, polygonal with flat or arcuate sides, irregular, uniform, non-uniform, consistent, variable, horseshoe-shaped, U-shaped, or kidney-shaped. In some embodiments, the lattice is rough, textured, porous, semi-porous, dimpled, knurled, toothed, grooved, or polished, for example, to engage and cut tissue. In some embodiments, the lattice forms a tunnel configured to guide, drive, or direct cut tissue into the opening, such as to fuse the device to the tissue. screw

[0069] In certain embodiments, the device is a screw, hi some embodiments, the screw is selected from a posted screw, a pedicle screw, a bolt, a transverse bone screw, an interbody screw, a uniaxial screw, a fixed angle screw, a polyaxial screw, a side-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.

[0070] In one embodiment, the device is a bone screw. In one embodiment, the device is a pedicle screw. Referring to Figure 1, a pedicle screw is shown implanted through a pedicle into the vertebral body of a vertebra. In one embodiment, the pedicle screw has a cage with a polymer retained within a cannulated and / or fenestrated portion of the screw.

[0071] In one embodiment, the inner core of the screw is a trephine for harvesting and harvesting autograft material at and / or during screw insertion.

[0072] In one embodiment, a post-implantation option prevents revision surgery by injecting polymer through the screw.

[0073] In some embodiments, the pedicle screws do not exhibit screw loosening, screw backout, rod breakage, or bone mineral density loss.

[0074] In one embodiment, the pedicle screw reduces one or more of screw loosening, screw backout, rod breakage, and bone mineral density loss.

[0075] The disclosed screw focuses bone ingrowth throughout the shaft to minimize shear stress at the distal tip and distribute micromotion evenly throughout the screw to promote bone ingrowth.

[0076] In some embodiments, the pedicle screw scaffolding provides options for patients with simple to complex bone mineral densities and immunocompromised conditions. In some embodiments, the scaffolding is impregnated with one or more biologics, antibiotics, demineralized bone matrix, nanotechnology, or tissue engineering therapies.

[0077] 5-16, the structure of the pedicle screws 300, 400, 500 is specifically designed to encourage bone ingrowth through the pedicle screws 300, 400, 500 by using a scaffolding 280 similar to the natural trabecular bone within the vertebral body. In combination with the threads 230 and the scaffolding 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.

[0078] With reference to FIGS. 2-16 , the pedicle screws 200, 300, 400, 500 disclosed herein overcome many of the drawbacks 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 tailored 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-screw interface. In some embodiments, the fatigue life of the pedicle screws is not reduced even 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.

[0079] 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 nail 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.

[0080] 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.

[0081] 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, remove, shear, dissect, or disrupt the tissue. In some embodiments, the cutting edge is configured to be cylindrical, circular, elliptical, oval, triangular, polygonal with 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 void, such as fusing a screw with tissue.

[0082] By manipulating the pedicle screw 200, 300, 400, 500, for example by rotation or translation, the cutting edges 271 of the screw cut tissue or bone and guide it into the core 260, thereby promoting bone ingrowth and fusion to the pedicle screw 200, 300, 400, 500. In some embodiments, tissue is embedded in the core 260, promoting bone ingrowth and fusion to the pedicle screw 200, 300, 400, 500. In some embodiments, a lattice is placed within the core 260 to form a scaffold 280 for bone ingrowth.

[0083] 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. In some embodiments, threads include multiple separate threads.

[0084] 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.

[0085] In one embodiment, the screw is a 3D-printed porous pedicle screw. Its 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 one embodiment, 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 diabetic-prone infections, and inject bone cement to further stabilize the construct in severely osteoporotic bone.

[0086] 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.

[0087] In one embodiment, 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 one embodiment, stem cell therapy is injected through the screw implant. In such an embodiment, the possibility of fracture is reduced.

[0088] In some embodiments, the surgeon can inject or spray autologous enriched 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 inside. The osteogenic stem cells then combine with the enriched blood stem cells and signal the process of mutation and replication, resulting in the formation of more osteogenic cells within the screw, subsequently forming a bone healing cascade directed within and around the screw. In these embodiments, the combination of the stem cells' (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.

[0089] 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 on the screw within the pedicle, to provide antibiotic delivery to the area. In some embodiments, the antibiotic is delivered for 2 to 6 weeks, thus reducing the likelihood of revision due to infection. manufacturing

[0090] The devices disclosed herein can be manufactured using a variety of methods. In some embodiments, the manufacturing includes machining, such as subtractive, deformative, or transformative manufacturing. In some embodiments, the manufacturing includes cutting, grinding, rolling, forming, molding, casting, forging, extruding, whirling, grinding, cold working, or a combination thereof. In some embodiments, the manufacturing includes a portion of the device formed by a medical machining process. In some embodiments, the machining uses computer numerically controlled (CNC) high-speed milling machines, Swiss machining equipment, CNC turning with living tooling, wire EDM 4-axis, and combinations thereof. In some embodiments, the 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.

[0091] 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.

[0092] 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, and 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.

[0093] In some embodiments, a portion of the device is manufactured by additive manufacturing and then mechanically attached to a surface of the device, for example, by welding, threading, adhesives, or staking.

[0094] 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 obtainable 2D or 3D images 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, patient anatomical imaging, 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.

[0095] 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. regenerative medicine

[0096] "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.

[0097] In some embodiments, tissue engineering is incorporated with the scaffolds or devices disclosed herein. Autologous graft incorporation occurs in five stages: inflammation, angiogenesis, osteoinduction, osteoconduction, and remodeling.

[0098] Inflammation lasts approximately 7 to 14 days. Initial injury to the local blood supply and cortical removal results in a hematoma around the bone graft, into which inflammatory cells invade. Fibroblasts in the inflamed tissue transform into a fibrovascular stroma. Perioperative anti-inflammatory medications reduce the rate of fusion due to the inflammatory process.

[0099] Vascular sprouts appear in the fibrovascular stroma, resembling scar tissue formation during angiogenesis. Primary membranous bone forms adjacent to the denuded bone. Minimal cartilage and endochondral ossification then occur.

[0100] During osteoinduction (weeks 4-5), repair involves increased vascularization, 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.

[0101] Bone regeneration is characterized by ingrowth and creep replacement into the recipient bone. Osteoblasts form new bone, while osteoclasts simultaneously resorb the grafted bone. A central zone of 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.

[0102] During remodeling at 6-10 weeks, a peripheral cortical rim forms around the fusion. Bone marrow activity increases, forming secondary cancellous bone. The cortical rim thickens. Trabecular processes extend to the center of the fusion. Remodeling is typically complete 1 year after device implantation.

[0103] Pseudarthrosis (nonunion) was the leading cause of postoperative pain and accounted for 45% to 56% of revisions. Bone fusion directly correlated with successful clinical outcome. Patients with pseudarthrosis were asymptomatic in approximately 30% of cases. Younger age groups had a significantly increased rate of symptomatic pseudarthrosis (43.8 vs. 52.1 years, p<0.01).

[0104] In one embodiment, bone marrow aspirate (BMA) with allograft substitutes for autologous bone graft in single-level revision posterolateral lumbar fusion (PLF). In one embodiment, bone marrow aspirate with allograft is more cost-effective than recombinant human bone morphogenetic protein-2 (rhBMP). In one embodiment, bone marrow-derived cell-enriched allograft is compared to autograft in bone grafting and spinal fusion procedures. In one embodiment, BMA increases the regenerative capacity of corticocancellous bone allograft. When treating unicameral bone cysts, the healing rate was high (98.7%) for bone marrow with demineralized bone matrix injection.

[0105] 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 non-exclusive and mean that there may be additional elements other than the listed elements.

[0106] 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.

[0107] While the disclosure described herein is susceptible to various modifications and alternative iterations, specific embodiments thereof 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 specific embodiments disclosed. 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]

[0108] The following examples are included to demonstrate specific 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 function well in the practice of the present disclosure. However, those skilled in the art should, in light of the present disclosure, understand that many changes can be made in the specific embodiments disclosed and still obtain the same or similar results without departing from the spirit and scope of the present disclosure. Accordingly, all matters are to be interpreted as illustrative and not limiting. [Table 1]

[0109] Referring to Figures 2-4, the pedicle screw 200 was 3D printed in titanium. The pedicle screw 200 included a thread 230 disposed around a shaft 240 extending between a proximal end 210 and a distal tip 220. The 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. 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 200 included a core 260 extending through the center of the pedicle screw 200 from the proximal end 210 to the distal tip 220. The distal tip 220 included two cutting members 270, each with a cutting edge 271.

[0110] 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 with a cutting edge 271.

[0111] 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 around 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 middle 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 with a cutting edge 271.

[0112] 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 can be placed through a bottom opening 592 of the tulip 590 and held in place with a pin 595 placed through a side opening 596 of the tulip 590.

[0113] The pedicle screw 500 had 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 scaffolding 280 exposed on the outer surface of the pedicle screw 500 between the middle 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.

[0114] 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.

[0115] 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.

[0116] 16 , when present, the tulip 590 comprises a 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 the tulip body 594, and a pair of side openings 596 between the at least one pair of tulip grooves 593 and the bottom opening 592. The at least one pair of tulip grooves 593 are configured to receive and operably couple the threads 230 of the shaft 540 when the distal tip 220 of the shaft 540 passes through the bottom opening 592 of the tulip 590. After the threads 230 engage the at least one pair of tulip grooves 593, a pair of pins 595 can be operably coupled to the tulip 590 through the pair of side openings 596.

[0117] 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. The built-in channels captured the autograft during insertion. The screws had a dual ball angulation and a low profile. The screws were equipped with a locking cap with reverse-angle threads. The screws could be cannulated or non-cannulated.

[0118] The screws ranged in length from 35 mm to 65 mm and in diameter from 4.5 mm to 8.5 mm. The rod acceptance was 5.5 mm.

[0119] 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. Furthermore, 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.

[0120] The device was cobalt chrome tested and met American Society for Testing and Materials (ASTM) standards 543, 1798, and 1717.

[0121] 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 immersion test, called 'Operation A' (mechanical stress and reagent exposure under standardized conditions of applied strain). These procedures 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.

[0122] ASTM Standard 1798 covers the measurement of uniaxial static and fatigue strength and resistance to loosening of component interconnection systems in spinal arthrodesis implants. This test method provides a means to mechanically characterize different designs of interconnections in 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 structures or substructures, nor does it define performance levels for spinal implants.

[0123] 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 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 comparative evaluation of spinal implant assemblies.

[0124] In one embodiment, the pedicle screws 200, 300, 400, 500 are individually packaged in a double Tyvek™ stripping tray.

[0125] In one embodiment, the pedicle screws 200, 300, 400, 500 are injected or sprayed with a material such as BMA concentrate, calcium phosphate, biologics, and / or antibiotics, and the filled or coated screws are allowed to rest for 10-15 minutes to absorb the material before insertion. Example 2 - Screw with Two Lumens

[0126] 17-19, the screw has discrete porous zones located proximally and distally. The porous structure supports cells embedded in the center of the screw. The screw also supports independent delivery of cement deployed through fenestrations at the distal tip of the screw.

[0127] Referring to Figure 17, the screw comprises a discrete internal porous lattice structure. The dual lumens allow for cell delivery to the proximal lattice and cement delivery to the distal lattice. The upper lumen communicates from the head of the screw to the distal porous (lattice) structure. Similarly, the lower lumen communicates from the head of the screw to the proximal porous (lattice) structure (Figure 18). The proximal lumen communicates with the proximal porous structure in contact with cortical bone. The distal lumen communicates with the distal porous structure in contact with cancellous bone. A dividing feature divides the aperture into the dual lumens (Figure 19).

[0128] In some embodiments, the screw includes three or more lumens, for example, four, five, or six lumens.

[0129] In some embodiments, the screw includes a thickened head-neck junction below the aperture, for example, to reduce the chance of the rod breaking during installation of the screw. Example 3 - Sheep Study

[0130] 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.

[0131] The first specific objective was to determine whether porous pedicle screws promote bone integration and pullout strength compared to the gold-standard pedicle screw / rod construct 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, superior results can be achieved with the disclosed porous pedicle screws in terms of bone integration and pullout strength compared to current pedicle screws.

[0132] For this purpose, 84 vertebral bodies ( L1 Bone mineral density (BMD) at L2-L3 and L4-L6 joints will be measured in six sheep one week before surgery and 24 and 36 weeks after surgery. Each subject will undergo two separate lumbar interbody fusions (LIFs) at the L2-L3 and L4-L5 joints. L1 and L6 will serve as untreated controls to compare changes with and without hardware. [Table 2]

[0133] In each subject, the titanium interbody cage and the bone cavity filler packed into the interbody cage were placed at L2 L3 The L2, L3, L4, and L5 segments are then placed between the L1 and L2 segments. Screws of 4.5, 5.5, or 6.5 mm diameter and 45±10 mm length are then inserted into the right and left pedicles within the L2, L3, L4, and L5 vertebral bodies. This configuration represents a conventional fusion device and surgical technique. Prior to insertion, the porous pedicle screws (treatment) are sprayed with autologous stem cell concentrate along the length of the porous pedicle screws.

[0134] 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.

[0135] 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 on 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), structure stiffness (degrees / Nm), and neutral zone (degrees).

[0136] Destructive pedicle screw pull-out tests are performed. Quasi-static ramping 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 is tested for N=1 of four screws from each, and counterclockwise quasi-static torque to loosen the screws yields the ultimate torque (Nm).

[0137] Other tests included micro-computed tomography (MicroCT) of each FSU and associated pedicle screw, qualitative 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 percentage of bone area within the ROI, percentage of fibrous tissue within the ROI, percentage of void space within the ROI, percentage of screw within the ROI, and percentage of bone ingrowth into the device.

[0138] 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. [Table 3]

[0139] The histopathological report will include, but is not limited to, a summary of methods and materials, tabular and qualitative data up to the final time point and conclusion, low-magnification images, and representative photomicrographs to illustrate the 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 with similar retrospective studies.

[0140] 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.

[0141] 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 osteoclast-mediated bone remodeling, angiogenesis, fibrosis, signs of implant degradation, and particulate debris. Histological reports will also be compared and contrasted between control, untreated, and treated 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. Injection of autologous stem cells into and around porous pedicle screws is expected to be safe compared to control screws, untreated screws, and previous studies.

[0142] 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.

[0143] 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 media 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.

[0144] Figure 1 shows the correlation between cell adhesion and porous pedicle screws with 3D printed titanium patterns. Porous pedicle screws demonstrate better stem cell adhesion than control and untreated controls, and similar adhesion rates to previous studies. Example 4 - Sheep studies on infection

[0145] Another six-animal study will focus on testing the feasibility of injecting calcium sulfate with an antibiotic mixture as a means of reducing infection rates after spinal fusion surgery. The primary objectives of this project are to determine (1) 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) whether injecting calcium sulfate with an antibiotic mixture can reduce infection rates after spinal fusion surgery, and (3) whether the tested pedicle screws have the topography and porous pattern to support the above-mentioned goal of injection.

[0146] 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 compared to controls (i.e., confirm that the infection has not spread to the hardware) and (2) reduce infection in the bone.

[0147] 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.

[0148] 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, controlled, well-powered animal study that will evaluate efficacy endpoints in a scientifically rigorous manner.

[0149] The experimental design and methods were essentially the same as those described above in the sheep study in Example 3, including Tables 2 and 3.

[0150] All U.S. or foreign references, patents, or applications cited in this application are incorporated by reference as if set forth herein in their entirety. In the event of a conflict, the material disclosed herein will control.

[0151] 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: a body having a proximal end and a distal tip; a scaffold for the body, the scaffold having a porous structure distributed in a proximal lattice in a first zone near the proximal end and a distal lattice in a second zone near the distal tip; an upper lumen at the proximal end in fluid communication with a first opening at the proximal end; a lower lumen at the distal tip in fluid communication with a second opening at the proximal end; A medical device comprising:

2. The medical device of claim 1 , further comprising a fenestration at the distal tip.

3. The medical device of claim 2 , configured to support independent delivery of cement deployed through the fenestration.

4. The medical device of claim 1 , wherein the porous structure supports cells embedded in the center of the medical device.

5. The medical device of claim 1 , configured to enable delivery of cells to the proximal lattice and delivery of cement to the distal lattice.

6. The medical device of claim 1 , wherein the proximal lattice, the distal lattice, or both, comprise a discrete internal porous lattice structure.

7. The medical device of claim 1 , wherein the upper lumen contacts cortical bone and the lower lumen contacts cancellous bone.

8. The medical device of claim 1 , further comprising a dividing feature configured to divide the upper and lower lumens.

9. The medical device of claim 1 , further comprising at least one additional lumen.

10. The medical device according to any one of claims 1 to 9, which is a bone screw having a head at the proximal end.

11. The medical device of claim 10, which is a pedicle screw.

12. 12. The medical device of claim 10 or 11, wherein the upper lumen communicates from the head of the bone screw to the distal lattice and the lower lumen communicates from the head of the bone screw to the proximal lattice.

13. The medical device of any one of claims 10 to 12, comprising thickened head-neck joints below the first opening and the second opening.

14. 14. The medical device of any one of claims 10 to 13, configured to reduce the likelihood of rod breakage during screw installation.

15. A medical method for treating a bone fracture in a patient in need thereof, comprising implanting a device according to any one of claims 1 to 14 into the patient's bone.

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