Device with lumen for bone transplantation

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, the body housing a stent having porous structures distributed in a proximal grid and a distal grid. 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 mesh. In some embodiments, the device is a bone screw having a thickened head-neck junction designed to reduce the likelihood of rod breakage during installation. The method includes implanting the device into a bone of a patient, thereby providing an innovative method for fracture treatment.

Description

[0001] This application claims the benefit of priority of U.S. Provisional Patent Application Serial No. 63 / 422,638, filed Nov. 4, 2022, the disclosure of which is hereby incorporated by reference in its entirety for all purposes.

[0002] The present disclosure relates to scaffold materials similar to natural bone, medical devices made from such scaffold materials, and related methods for bone grafting.

[0003] Spinal fusion is a commonly indicated surgery for controlling fractures, instability, and common degenerative conditions, including low back pain. Fusion techniques use bone grafts and hardware, such as pedicle screws, to promote the growth of two vertebral bodies together. Existing lumbar implant designs are smooth-threaded pedicle screws that are fixed in the vertebrae with rods to maintain the corrected height and angle until fusion is achieved.

[0004] It is estimated that low back pain affects 60%-80% of people globally. 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 surgery is high, approximately 10%-46%.

[0005] In a review of spinal fusion surgeries within the PubMed database, 11,692 patients were extracted. There were 3,646 complications, the mean age at surgery was 53.3 years (range: 25 years - 77 years), and the mean follow-up time 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 not changed substantially over the years. For example, due to computer navigation, augmented reality, minimally invasive surgery (MIS) methods, discoplasty, bone-stimulating pedicle screws, and bone void filler options, lumbar interbody fusion (LIF) techniques have advanced. However, due to an increasing patient population and high failure rates, the number of patients developing failed back surgery syndrome (FBSS) is increasing. (FBSS is a situation where the outcome of lumbar surgery does not meet the pre-operative expectations of the patient and the surgeon).

[0007] The gold standard for lumbar interbody fusion involves inserting smooth, threaded screws into each pedicle (two per vertebral level) and placing rods into the tulip-shaped heads of the pedicle screws to stabilize the construct until fusion is achieved. However, since 1975, there has been little technological advancement in spinal stabilization systems, and these constructs do not address key long-term stability issues related to the quality of bone mineral density and patient health. The hardware used in lumbar fusions is subjected to significant forces that result in hardware breakage and loosening (the so-called "windshield wiper effect"). The estimated variation in the frequency of screw loosening during spinal fusion surgery is significant, but recent reports estimate that the loosening rate exceeds 40%, with nearly 10% being partial pullout. This loosening due to lack of fusion can place nerves or blood vessels at risk and often requires removal of the hardware and repeat surgery.

[0008] Unfortunately, spinal revision surgery also has a poor success rate. The success rate for secondary revision cases is 30%, for the third surgery it is 15%, and for the fourth surgical intervention it is 5%. Additionally, adult spinal deformity patients who have previously undergone two or more revisions exhibit more coronal and sagittal imbalance and a worse functional status. Other potential complications of LIF are dural tear, nerve injury, pseudarthrosis, infection, and wound healing problems.

[0009] Another complication of lumbar fusion is infection. Surgical site infection (SSI) represents a major problem in healthcare and is responsible for approximately 8,000 deaths per year 21. The direct and indirect costs attributable to SSI are estimated to total between $1 billion and $10 billion annually. Spinal instrumentation surgery has a greater risk of SSI, resulting in a higher infection rate compared to other orthopedic surgeries. The estimated incidence of SSI originating from spinal surgery ranges between 0.2% and 16.7%. A recent meta-analysis showed that the SSI rate resulting from instrumented spinal surgery is 4.4%. Deep incisional and organ space SSIs account for 80% of these infections and are associated with increased morbidity, longer hospital stays, and greater healthcare costs.

[0010] In addition, regardless of the material used, bone mineral density decreases after implantation of a medical device. This loss results in common medical device failures, including screw loosening, screw pullout, and rod fracture. Although many devices facilitate intervertebral cage fusion, none have been developed to support and increase bone mineral density within the vertebral body. Moreover, the structure of cortical bone within the vertebrae is different from bone in other parts of the body.

[0011] These challenges related to long-term stability, such as bone quality and functional healing ability, have not been met. None of the prior arts have addressed the first two reasons for revision surgery of implant failure: pedicle screw pullout and rod fracture before the patient achieves fusion. Smooth threaded pedicle screws and rods do not address the issue of bone mineral density quality and patient health. Summary of the Invention

[0012] The present disclosure provides a medical device that includes a body having a proximal end and a distal tip. The device includes a stent in the body, the stent having a porous structure that is distributed in a proximal mesh in a first region near the proximal end and a distal mesh in a second region near the distal tip. The device also has an upper lumen in the proximal end that is in fluid communication with a first opening at the proximal end, and a lower lumen in the distal tip that is in fluid communication with a second opening at the proximal end.

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

[0014] Additional embodiments and features are set forth in part in the following description. They will become apparent to those skilled in the art upon review of the specification, or may be learned by practicing the embodiments discussed herein. A further understanding of the nature and advantages of certain embodiments may be realized by reference to the remaining portions of the specification and the drawings that form a part of the present disclosure. Brief Description of the Drawings

[0016] Figure 1 is a top view of a drawing showing a pedicle screw implanted into the vertebral body of a vertebra through the pedicle.

[0017] Figure 2 Shows a side plan view of an embodiment of a pedicle screw printed in titanium 3D.

[0018] Figure 3 Shows Figure 2 the top plan view of the pedicle screw.

[0019] Figure 4 Shows Figure 2 the bottom plan view of the pedicle screw.

[0020] Figure 5 Shows a side plan view of an embodiment of a 3D printed pedicle screw with a stent disclosed herein.

[0021] Figure 6 Shows Figure 5 the top plan view of the pedicle screw.

[0022] Figure 7 Shows a Figure 5 bottom plan view of a pedicle screw.

[0023] Figure 8 Shows a side plan view of another embodiment of a 3D printed pedicle screw with a stent disclosed herein.

[0024] Figure 9 Shows a Figure 8 top plan view of a pedicle screw.

[0025] Figure 10 Shows a Figure 8 bottom plan view of a pedicle screw.

[0026] Figure 11 Shows a side plan view of an embodiment of a porous pedicle screw.

[0027] Figure 12 Shows an exploded view of a Figure 11 porous pedicle screw with a tulip-shaped member and a pin.

[0028] Figure 13 Shows a Figure 11 top plan view of the cap of a porous pedicle screw.

[0029] Figure 14 Shows a Figure 11 side plan view of the cap of a porous pedicle screw.

[0030] Figure 15 Shows a Figure 11 perspective view of the saddle of a porous pedicle screw.

[0031] Figure 16 Shows a Figure 12 perspective view of a tulip-shaped member.

[0032] Figure 17 Shows a screw including two discrete internal porous grid structure regions. The double lumen allows for the delivery of cells to the proximal grid and the delivery of cement to the distal grid.

[0033] Figure 18 Is a Figure 17 drawing of the screw, showing the lower lumen communicating with the proximal porous (grid) structure from the screw head.

[0034] Figure 19 Is a top perspective view of the proximal end of the screw, showing the dividing feature that divides the hole into a double lumen.

[0035] The present disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, in which like reference numerals represent like structural elements. The drawings provide exemplary embodiments or aspects of the present disclosure and do not limit the scope of the present disclosure. Detailed Description

[0036] The present disclosure provides a medical device that includes a body having a proximal end and a distal tip. The device includes a stent in the body, the stent having a porous structure that is distributed in a proximal mesh in a first region near the proximal end and a distal mesh in a second region near the distal tip. The device also has an upper lumen in the proximal end that is in fluid communication with a first opening at the proximal end, and a lower lumen in the distal tip that is in fluid communication with a second opening at the proximal end.

[0037] In some embodiments, the medical device further includes perforations at the distal tip.

[0038] In certain embodiments, the medical device is configured to support independent delivery of a cement deployed through the perforations. In some embodiments, the porous structure of the medical device supports cells integrated into the center of the medical device. In certain embodiments, the medical device is configured to allow delivery of cells to the proximal mesh and delivery of cement to the distal mesh.

[0039] In some embodiments, the proximal mesh or the distal mesh or both of the medical device include a discrete internal porous mesh structure. In certain embodiments, the upper lumen of the medical device contacts cortical bone, and the lower lumen contacts cancellous bone. In some embodiments, the medical device further includes a separating feature configured to separate the upper lumen and the lower lumen. In certain embodiments, the medical device further includes at least one additional lumen.

[0040] In some embodiments, the medical device is a bone screw having a head at the proximal end. In certain embodiments, the bone screw is a pedicle screw. In some embodiments, the upper lumen of the bone screw is in communication with the distal mesh from the head of the bone screw, and the lower lumen is in communication with the proximal mesh from the head of the bone screw. In certain embodiments, the bone screw includes a thickened head-neck junction below the first and second openings. In some embodiments, the bone screw is configured to reduce the likelihood of rod breakage during screw installation.

[0041] In certain embodiments, a medical method of treating a fracture in a patient in need thereof includes implanting the medical device of any of the foregoing embodiments into the patient's bone.

[0042] Bracket

[0043] Surface curvature and Minkowski bone morphological curvature maps (functions that restore the concept of distance on a linear space) indicate that the porous matrix in trabecular bone within vertebrae is significantly different compared to other regions of the skeletal anatomy. The load of traditional smooth threaded pedicle screws may be too high for vertebrae because bone mineral density decreases after implantation.

[0044] Porous 3D printed scaffolds promote bone integration, fusion, and fixation within bone. The open framework with the scaffold is similar to the open framework of natural bone. This similarity allows physicians to use other reagents for patient - specific selection, thus promoting bone formation and / or stabilizing the device.

[0045] Triangular porosity sequences have been used in the prior art. Circular, square / rectangular shapes, and varied patterns align more closely with the natural vertebral structure. Additionally, the structure of the scaffold reduces the likelihood of revision of the medical devices fabricated from it, such as screw loosening, screw pull - out, rod fracture, and lower bone mineral density.

[0046] In certain embodiments, the disclosed scaffolds and devices integrate orthopedic products with regenerative medicine to prevent the risk of delayed fusion of bone with the implanted device.

[0047] In certain embodiments, the scaffold includes one or more structural cues selected from porosity, pore size, particle size, and surface topography. Porosity and pore size cue signals for mechanical strength, cell settlement, and cell migration. Particle size addresses signal protein absorption, cell adhesion, cell proliferation, and cell adhesion. Surface topography addresses signal - specific surface regions, cell adhesion, and material - tissue interfaces. Other scaffold features include pH and wall thickness. In certain embodiments, one or more structural cues enhance at least one of multipotent mesenchymal stem cell (MSC) differentiation, osteoblast growth, extracellular matrix (ECM) deposition, and new bone formation. In certain embodiments, new bone formation occurs after MSC differentiation, osteoblast growth, ECM deposition, or a combination thereof.

[0048] Bone

[0049] Bone can generally be classified into cancellous bone and cortical bone. "Cancellous bone", also known as "trabecular bone" or "spongy bone", is a lightweight, porous bone that encloses many large spaces, resulting in a honeycombed or spongy appearance. The bone matrix or framework is organized into a three - dimensional grid of bony projections called trabeculae that align along stress lines. The spaces between them are usually filled with bone marrow and blood vessels. In cross - section, the trabeculae of cancellous bone may appear like septa. However, they are topologically different in three - dimensional space, where the trabeculae are generally rod - shaped or columnar, and the septa are sheet - shaped.

[0050] Cancellous bone makes up approximately 20% of the human skeleton, providing structural support and flexibility without compact bone. It is found in most areas of bone that are not subject to large mechanical stresses. It forms most of the expanded ends (epiphyses) of long bones and is a major component of the ribs, scapulae, flat bones of the skull, and various short flat bones elsewhere in the skeleton.

[0051] Due to the increasing frequency of total joint replacements and their impact on bone remodeling, understanding the stress-related and adaptive processes of trabecular bone has become a central concern for bone physiologists. To understand the role of trabecular bone in age-related bone structure and bone-implant system design, the mechanical properties of trabecular bone are studied as they vary with anatomical site, density, and age. Thus, mechanical factors, including modulus, uniaxial strength, and fatigue performance, are also investigated.

[0052] High porosity gives cancellous bone its compliance. Large variations in structure result in high heterogeneity. Modulus and strength are inversely proportional to porosity and highly dependent on the porosity structure. Typically, the percentage of porosity in cancellous bone is between 75% and 95%. The density is between 0.2 g / cm 3 and 0.8 g / cm 3 Porosity can reduce the strength of bone but also reduces its weight.

[0053] Porosity and its structure affect the strength of the material. Thus, the microstructure of trabecular bone is usually oriented. Where mechanical stiffness and strength are greatest, the "grains" of the pores 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 that of vertebrae, is between 800 Mpa and 14,000 Mpa. Its fracture strength is between 1 MPa and 100 MPa.

[0054] "Cortical bone" or "compact bone" is much denser than cancellous bone. It forms the hard exterior (cortex) of bone. Cortical bone gives bone a smooth, white, and solid appearance. It accounts for approximately 80% of the total bone mass of the adult skeleton. Cancellous bone is usually surrounded by a shell of cortical bone, which provides greater strength and stiffness. The open structure of cancellous bone enables it to dampen sudden stresses, such as load transfer through joints. Different bone-to-space ratios are found in different bones depending on the need for strength or flexibility. Cancellous bone also has a relatively high level of metabolic activity.

[0055] "Wolff's law" states that the bones of a healthy person or animal adapt to the loads placed upon them. For example, if the load on a particular bone increases, the bone will remodel itself over time to become stronger to resist that load.

[0056] Vertebra

[0057] Each vertebra is an irregular bone with a complex structure composed of bone and some hyaline cartilage in the vertebrate spinal column. The proportions vary according to the spinal segment and vertebrate species.

[0058] The basic structure of the vertebra varies. Most of it is the body, and the central part is the vertebral body. The upper and lower surfaces of the vertebral body attach to the intervertebral discs. The posterior part forms the vertebral arch of eleven parts, which consists of two pedicles, two laminae, and seven processes. The laminae attach to the ligamentum flavum (spinal ligament). There are vertebral notches formed by the shape of the pedicles, and when the vertebrae articulate, this vertebral notch forms the intervertebral foramen. These foramina are the entry and exit ducts for the spinal nerves. The vertebral body and the vertebral arch form the vertebral foramen, which is a large central opening that houses the spinal canal, and the spinal canal surrounds and protects the spinal cord.

[0059] The pedicles and laminae form the vertebral arch. Two pedicles extend from the sides of the vertebral body to connect the vertebral body to the vertebral arch. The pedicles are short thick projections that extend posteriorly from the junction of the posterolateral surfaces of the vertebral body on its upper surface, one on each side. From each pedicle, a broad plate called the "lamina" projects posteriorly and medially to connect and complete the vertebral arch and form the posterior boundary of the vertebral foramen, thus completing the triangle of the vertebral foramen. The upper surface of the lamina is rough for attachment to the ligamentum flavum. These ligaments connect the laminae 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, this notch aligns with the notch on the adjacent vertebra, thus forming the intervertebral foramen opening. This foramen allows the spinal nerves and associated blood vessels to enter and leave each vertebra. Articulating vertebrae provide a strong strut for the body.

[0060] Device

[0061] The present disclosure provides an apparatus formed from the scaffolds disclosed herein. In certain embodiments, the scaffolds are utilized to make the apparatus hollow and porous. In certain embodiments, the apparatus includes a threaded distal region, an optional threaded central region, and an optional threaded proximal region according to the compressive force.

[0062] In certain embodiments, the apparatus is selected from pedicle screws, hollow pedicle screws, porous pedicle screws, large head screws, small head screws, headless screws, traumatic hip fracture devices, glenoid cages, screws for glenoid cages, traumatic plates, tibial stems, femoral stems, hammer toe implants, screw fusion systems, Charcot foot deformity correction, radial head fracture devices, high tibial osteotomy, deformity correction, vertebrectomy cages, tumor correction, anchors, dental implants, maxillofacial implants, and sports medicine anchors.

[0063] In some embodiments, the device is selected from hip fracture systems, reverse total shoulders, dental implants, upper extremity hardware, lower extremity hardware, total joint replacement implants, total joint revision implants, spinal fusion, spinal arthroplasty, regenerative therapies, cartilage grafts, maxillofacial hardware, and cardiac implants.

[0064] In some embodiments, the screw is configured to have features that facilitate bone growth through the screw structure from the opposite side, thereby allowing the bone to be joined by the screw. In some embodiments, the structure is narrow, such as through the screw threads, thereby allowing rapid ingrowth. In some embodiments, the deeper the structure, such as through a small diameter, the stronger the bond. In some embodiments, the feature is a void or porosity in the screw or is configured to promote bone growth. In some embodiments, the structure collects autograft in a channel inside the device. In some embodiments, the feature is impregnated with one or more polymers.

[0065] In some embodiments, the device is configured to enhance the stability and fixation of bone screws within bone and improve bone mineral density. In some embodiments, the device includes a spinal implant that is configured to engage cortical and cancellous bone within a vertebra. In some embodiments, the device is configured to resist and / or prevent toggling of the bone screw under load on the bone screw when the bone screw engages dense cortical bone and less dense cancellous bone. 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, pullout of the bone screw from the vertebra. In some embodiments, the device is configured to facilitate bone ingrowth to improve the attachment of bone to the bone screw. In some embodiments, the bone screw is anchored in the bone, thereby reducing pullout. In some embodiments, the bone screw is designed to dissipate micromotion and reduce shear to enhance bone mineral density.

[0066] In some embodiments, the device includes a bone screw having bone ingrowth 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 bone screw structure from the opposite side, thereby allowing the bone to be joined by those bone screw structures. In some embodiments, the bone screw includes features that can be narrow, such as through the bone screw threads, which will allow rapid ingrowth. In some embodiments, the bone screw includes features that can be deeper, such as through a small diameter, which will provide a greater volume of bone ingrowth. In some embodiments, the bone screw includes features that can be voids or cavities through opposite sides of the bone screw and / or voids or cavities entering and leaving the same or adjacent surfaces. In some embodiments, the void or cavity can contain a scaffold for bone attachment or a porous structure on the void surface.

[0067] In some embodiments, a bone screw includes features or structures that can be disposed along an axial portion of the bone screw. In some embodiments, a bone screw includes features or structures that can be disposed continuously along a surface of the bone screw (such as, for example, along a distal end). In some embodiments, a bone screw includes features or structures that can be disposed discontinuously along a portion of the bone screw. In some embodiments, a bone screw includes features or structures that can include a scaffold or a polymer.

[0068] In some embodiments, a device includes a spinal implant having a hybrid configuration that combines manufacturing methods such as, for example, one or more previously fabricated features and materials and manufacturing methods such as, for example, one or more additive manufacturing features and materials. In some embodiments, additive manufacturing includes 3-D printing. In some embodiments, additive manufacturing includes fused deposition modeling, selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, laminated object manufacturing, and stereolithography. In some embodiments, additive manufacturing includes one or more selected from rapid prototyping, desktop manufacturing, direct manufacturing, digital manufacturing, instant manufacturing, and on-demand manufacturing. In some embodiments, a device includes a spinal implant fabricated by a fully additive process and grown or otherwise printed.

[0069] In certain embodiments, a device includes one or more selected from demineralized bone matrix (DBM), pre-filled DBM, pre-filled synthetic DBM, unfilled DBM, and magnesium-infused titanium.

[0070] In some embodiments, a device includes a spinal implant, such as a bone screw fabricated by combining traditional manufacturing methods and additive manufacturing methods. In some embodiments, a bone screw is fabricated by applying an additive manufacturing material, where the bone screw can benefit from the materials and properties of additive manufacturing. In some embodiments, traditional materials are used, where benefits such as physical properties and cost are superior to those provided by additive manufacturing features and materials.

[0071] In some embodiments, a device treats spinal disorders selected from degenerative disc disease, herniated disc, osteoporosis, spondylolisthesis, stenosis, scoliosis, other curvature abnormalities, kyphosis, tumors, and fractures.

[0072] "Treatment" of a disease or disorder refers to conducting a procedure, which may include administering one or more drugs to a patient, using an implantable device, and / or using an instrument for treating a disease (such as a minimally invasive discectomy instrument for removing a herniated or protruding disc and / or bone spur) to alleviate the signs or symptoms of the disease or disorder. Treatment does not require complete remission of the signs or symptoms, does not require a cure, and specifically includes procedures that have a marginal effect on the patient. For example, treatment may include suppressing a disease, such as hindering its development, or alleviating a disease, such as causing regression.

[0073] "Prevention" refers to alleviating before the signs or symptoms of a disease or disorder appear. Thus, prevention includes preventing a disease from occurring in patients who may be predisposed to the disease but have not been diagnosed as having the disease.

[0074] "Tissue" includes soft tissue, ligament, tendon, cartilage, and / or bone. In certain embodiments, the tissue is cancellous bone, cortical bone, or corticocancellous bone.

[0075] In some embodiments, the device is used in conjunction with other skeletal and bone-related applications, including diagnosis and treatment. In some embodiments, the device is alternatively used for surgical treatment of a patient in the prone or supine position, and / or various surgical approaches are used for the spine, including anterior, posterior, posterior midline, lateral, posterolateral, and / or anterolateral approaches, as well as other body regions, such as the maxillofacial region and extremities. The device may also be alternatively used in procedures for treating the lumbar, cervical, thoracic, sacral, and pelvic regions of the spine. The device can also be used in animals, bone models, and other non-living matrices, for example, for training, testing, and demonstration.

[0076] In certain embodiments, the device is a customized medical device. In certain embodiments, the device is applicable to sports medicine.

[0077] In certain embodiments, the device is temperature-sensing. In certain embodiments, the device is pH-balanced.

[0078] In certain embodiments, the device is manufactured with a porogen to have a porosity that is spherical, cubic, rectangular, elongated, tubular, fibrous, disc-shaped, platelet-shaped, polygonal, or a mixture thereof. In some embodiments, the porosity is based on a plurality of macropores, micropores, nanopore structures, and / or combinations thereof.

[0079] In certain embodiments, the device is made of a biologically acceptable material suitable for medical applications, including metals, synthetic polymers, ceramics, bone materials, and composites thereof. In certain embodiments, the device includes one or more selected from metals, ceramics, rubber, hydrogel, rigid polymers, fabrics, bone materials, and composites thereof.

[0080] In certain 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, superelastoplastic metals such as In certain embodiments, the device comprises ceramics and their composites, such as calcium phosphate (e.g., Skelite TM ). In certain 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 copolymers, and polyolefin rubbers. In certain embodiments, the device comprises a hydrogel. In certain embodiments, the device comprises a fabric. In certain embodiments, the device comprises a rigid polymer selected from polyphenylene, polyimide, polyetherimide, polyethylene, and epoxy resins. In certain embodiments, the device comprises a bone material selected from autograft, allograft, xenograft, or transgenic cortical bone and / or corticocancellous bone. In certain embodiments, the device comprises a tissue growth or differentiation factor. In certain embodiments, the device comprises a resorbable 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 a resorbable polymer, a fully resorbable material (such as a calcium-based ceramic, e.g., calcium phosphate, tricalcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate) or other resorbable polymers (such as polyketones, polyglycolide, polytyrosine carbonate, polycaprolactone) and other combinations.

[0081] In certain 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 copolymers, polyolefin rubbers, synthetic collagen, and collagen matrix. In certain embodiments, the device comprises synthetic collagen. In certain embodiments, the device comprises a collagen matrix.

[0082] In certain embodiments, the device comprises magnesium, vitamins, and minerals. "Vitamin" refers to an organic molecule (or a group of chemically closely related molecules, i.e., vitamers) that is an essential micronutrient required by an organism in small amounts for the normal functioning of its metabolism. Some sources list fourteen vitamins by including choline, but major health organizations typically list thirteen: vitamin A (as all-trans-retinol, all-trans-retinyl esters, and all-trans-β-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 menaquinones). In the context of nutrition, "mineral" refers to a chemical element required as an essential nutrient for an organism to perform functions necessary for life, including potassium, chlorine, sodium, calcium, phosphorus, magnesium, iron, zinc, manganese, copper, iodine, chromium, molybdenum, selenium, and cobalt.

[0083] In certain embodiments, the device comprises a metal selected from the group consisting of iron, stainless steel alloy, aluminum, commercially pure titanium, titanium alloy, grade 5 titanium, superelastic titanium alloy, magnesium-infused titanium, cobalt-chromium alloy, superelastic metal alloys such as nitinol, superelastoplastic metals such as In certain embodiments, the device comprises titanium. In certain embodiments, the device comprises iron.

[0084] In certain embodiments, the device is manufactured or 3D printed from materials such as titanium, titanium alloy, cobalt-chromium alloy, carbon fiber, magnesium-infused titanium, iron, or stainless steel. In certain embodiments, the device is made from a shape memory alloy or a shape memory polymer, thereby allowing the device to conform to the anatomical shape of the patient's body.

[0085] In certain embodiments, the device comprises magnesium-infused titanium. In certain embodiments, the device comprises an angiotensin receptor blocker coating. In certain embodiments, the device comprises a type 1 collagen coating. In certain embodiments, the device is infused with an antibiotic.

[0086] In certain embodiments, the device is used to treat an affected part of a vertebra. The physician gains access to the surgical site, including the vertebra, in any suitable manner, such as by incising and retracting tissue. In certain embodiments, the device comprises bone screws to enhance the surgical treatment. In certain embodiments, the device can be pre-assembled for delivery to the surgical site or assembled in situ. In certain embodiments, the device is completely or partially modified, removed, or replaced.

[0087] In certain embodiments, the device is used with a surgical method or technique, which includes but is not limited to open surgery, mini-incision surgery, minimally invasive surgery (MIS), and percutaneous surgical implantation, whereby access to the vertebrae is achieved through a small incision or a cannula provides a protected passage to the area. Once access to the surgical site is obtained, surgical treatment, such as vertebrectomy or discectomy, can be performed to treat a disease or disorder.

[0088] In certain embodiments, the surface of the device includes a non-solid configuration, such as a mesh. In some embodiments, the non-solid configuration includes a porous structure or a trabecular configuration.

[0089] In various embodiments, the non-solid configuration is configured to provide one or more paths to assist bone growth within the device and through from one surface of the device to the opposite surface. In some embodiments, the mesh includes one or more sections, layers, or substrates. In some embodiments, one or more sections, layers, or substrates of the mesh are arranged side by side, offset, staggered, stepped, tapered, end-to-end, spaced apart, in series, or in parallel. In some embodiments, the mesh 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 mesh layers are arranged within the wall in a side-by-side parallel orientation. In certain embodiments, the mesh includes one or more layers of a material matrix.

[0090] In some embodiments, the mesh includes 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. In some embodiments, the plurality of nodes and openings are arranged in parallel.

[0091] In some embodiments, the mesh forms a file-like configuration. In some embodiments, the mesh is configured to engage tissue. In certain embodiments, the engagement of the mesh is to cut, shave, shear, incise, or disrupt tissue. In some embodiments, the mesh includes a configuration selected from the following: cylindrical, circular, oval, rectangular, triangular, polygon with planar or arcuate side portions, irregular, uniform, non-uniform, consistent, variable, horseshoe-shaped, U-shaped, or kidney-bean-shaped. In some embodiments, the mesh is rough, textured, porous, semi-porous, recessed, knurled, toothed, grooved, or polished, for example to engage and cut tissue. In some embodiments, the mesh forms a tunnel that is configured to direct, drive, or guide the cut tissue to an opening, such as to fuse the device to the tissue.

[0092] Screw

[0093] In certain embodiments, the device is a screw. In some embodiments, the screw is selected from pedicle screws, vertebral screws, bolts, bone screws for side plates, intervertebral screws, uniaxial screws, fixed-angle screws, multi-axial screws, side-loading screws, sagittal adjustment screws, lateral sagittal adjustment screws, tapered tips, double-rod multi-axial screws, midline lumbar fusion screws, and / or sacral screws.

[0094] In certain embodiments, the device is a bone screw. In certain embodiments, the device is a pedicle screw. Referring Figure 1 , a pedicle screw implanted through the pedicle into the vertebral body of a vertebra is shown. In certain embodiments, the pedicle screw has a cage that has a polymer retained within the hollow and / or porous portion of the screw.

[0095] In certain embodiments, the inner core of the screw is a trephine to collect and harvest autograft during and / or upon insertion of the screw.

[0096] In certain embodiments, post-implantation options prevent revision surgery by injecting a polymer through the screw.

[0097] In certain embodiments, the pedicle screw does not exhibit screw loosening, screw pullout, rod breakage, or reduced bone mineral density.

[0098] In certain embodiments, the pedicle screw has reduced one or more of screw loosening, screw pullout, rod breakage, and reduced bone mineral density.

[0099] The disclosed screws focus bone growth along the entire shaft to minimize shear stress at the distal tip and to evenly disperse micromotion across the entire screw to promote bone ingrowth.

[0100] In certain embodiments, the scaffold of the pedicle screw provides options for patients with simple to complex bone mineral density and immunocompromised patients. In certain embodiments, the scaffold is impregnated with one or more biologics, antibiotics, demineralized bone matrix, nanotechnology, or regenerative medicine therapies.

[0101] Referring Figures 5 - 16 , the structures of pedicle screws 300, 400, 500 are specifically designed to assist bone ingrowth through pedicle screws 300, 400, 500 by using a scaffold 280 that resembles natural trabecular bone in the vertebral body. In combination with the threads 230 and the scaffold 280, the core 260 aids in autograft harvest during insertion to push the autograft into a built-in channel within the core 260 of pedicle screws 300, 400, 500. The walls around the holes harvest the autograft and act as a trephine. This structure also aids in the structural integrity of pedicle screws 300, 400, 500, resists bone mineral density loss, and reduces micromotion.

[0102] Reference Figures 2 - 16 , the pedicle screws 200, 300, 400, 500 disclosed herein overcome many of the failures of prior art pedicle screws. In certain embodiments, the pedicle screw does not have a windshield wiper effect. In certain embodiments, the pedicle screw resists pullout. In certain embodiments, the pedicle screw does not exhibit excessive micromotion. In certain embodiments, the pedicle screw has low-frequency, low-toxicity microorganisms detected by ultrasonic treatment, such as due to individual screw sterilization and packaging. In certain embodiments, the head and shaft of the pedicle screw resist failure. In certain embodiments, the pedicle screw is suitable for each type of bone quality. In certain embodiments, the pedicle screw has sufficient thread depth. In certain embodiments, the pedicle screw withstands the insertion torque, particularly at the junction of the head and the screw. In certain embodiments, when the screw is fully inserted, the fatigue life of the pedicle screw is not reduced. In certain embodiments, the pedicle screw has good instrumentation. In certain embodiments, the pedicle screw achieves angulation for rod acceptance. In certain embodiments, the pedicle screw does not have cyclic loading based on physiological conditions during walking. In certain embodiments, the pedicle screw does not fail in long-segment posterior cervical fusion and does not require an accompanying C6 or T1 support pedicle. In certain embodiments, the pedicle screw distributes stress. In certain embodiments, the pedicle screw does not immunocompromise the patient. In certain embodiments, the pedicle screw does not include PEEK. In certain embodiments, the pedicle screw does not have tulip-shaped or locking cap stress.

[0103] In some embodiments, the distal tip 220 of the pedicle screws 200, 300, 400, 500 has a surface configuration selected from angled, irregular, uniform, non-uniform, offset, staggered, tapered, arcuate, wavy, reticulated, porous, semi-porous, recessed, pointed, textured, or a combination thereof. In some embodiments, the distal tip 220 includes a nail configuration, barbs, expansion elements, raised elements, threads, and / or spikes to provide a manufacturing platform for forming a portion thereon via additive manufacturing. In some embodiments, the distal tip 220 has a cross-sectional configuration selected from oval, rectangular, triangular, square, polygonal, irregular, uniform, non-uniform, offset, staggered, tapered, or a combination thereof.

[0104] In some embodiments, the pedicle screws 200, 300, 400, 500 include threads 230 extending between a proximal end 210 and a distal tip 220. In some embodiments, the threads 230 include an external thread form. In some embodiments, the thread form includes a leading edge 231 having a front surface 235 and a trailing edge 232 having a rear surface 236. The front surface 235 defines a first opening 251. The rear surface 236 defines a second opening 252. In some embodiments, the first opening 251 and the second opening 252 are axially aligned. In some embodiments, the first opening 251 and the second opening 252 are circumferentially disposed around the thread form.

[0105] In some embodiments, the front surface 235 and / or the rear surface 236 include at least one tissue collection member. In some embodiments, the tissue collection member includes a cutting edge. In some embodiments, the cutting edge is configured to be file-like. In some embodiments, the cutting edge is configured to engage tissue, e.g., to cut, shave, shear, incise, or disrupt tissue. In some embodiments, the cutting edge is configured to be cylindrical, circular, oval, rectangular, triangular, polygonal, having planar or arcuate sides, irregular, uniform, non-uniform, consistent, variable, horseshoe-shaped, U-shaped, or kidney bean-shaped. In some embodiments, the cutting edge is rough, textured, porous, semi-porous, recessed, knurled, toothed, grooved, or polished to engage and cut tissue. In some embodiments, the cutting edge forms a tunnel that is configured to direct, drive, or guide the cut tissue to a void, such as fusing the screw to the tissue.

[0106] For example, the pedicle screws 200, 300, 400, 500 are manipulated, such as by rotation or translation, such that the cutting edge 271 of the screw cuts tissue or bone and directs the tissue or bone to the core 260, thereby promoting bone growth and fusion to the pedicle screws 200, 300, 400, 500. In some embodiments, the tissue is embedded in the core 260 to promote bone growth and fusion to the pedicle screws 200, 300, 400, 500. In some embodiments, a mesh is disposed within the core 260 to form a scaffold 280 for bone growth.

[0107] In some embodiments, the threads 230 are configured to be thin, closely spaced, or shallow for engaging tissue. In some embodiments, the threads 230 include an increased pitch and an equal lead between the number of thread turns. In some embodiments, the threads 230 include a smaller pitch or more thread turns per axial distance to make the fixation to tissue a stronger fixation or resist loosening from tissue. In some embodiments, the threads 230 are configured to be continuous along a portion. In some embodiments, the threads 230 are configured to be discontinuous, staggered, or non - continuous. In certain embodiments, the threads 230 include a single thread turn. In certain embodiments, the threads include multiple discrete threads.

[0108] In some embodiments, the threads 230 include a penetrating element, such as selected from a staple configuration, barbs, expansion elements, raised elements, threads, or spikes. In some embodiments, the threads 230 are configured to be self - tapping or discontinuous 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 includes a solid outer surface.

[0109] In certain embodiments, the screw is a 3D - printed porous pedicle screw. Its porosity mimics natural vertebrae to attach and retain stem cells, growth factors, and other proteins within the structure of the pedicle screw and promote bone growth through the screw, thereby stabilizing the entire construct. During insertion into the vertebra, the built - in trephine collects autograft and regenerative cells within the porous matrix. The disclosed topography attracts bone - forming stem cells within and around the device, thereby reducing overall construct macro - motion. In certain embodiments, the device enables the surgeon to meet patient - specific needs, such as but not limited to, the option of spraying / injecting regenerative products to stimulate the osteogenic cascade of bone formation, actively injecting the screw scaffold with antibiotics for diabetes - susceptible infections, and injecting bone cement to further stabilize the construct in severely osteoporotic bone.

[0110] In certain embodiments, the screw reduces the revision rate, improves bone mineral density, and / or addresses patient - specific needs during spinal fusion. In certain embodiments, the bone mineral density is improved, the construct is stabilized, and the likelihood of revision is reduced.

[0111] In certain embodiments, the screw is a 3D printed titanium porous pedicle screw that has a porous pattern similar to natural bone throughout the screw. Without wishing to be bound by theory, the function of the porous pattern is to attach to the surrounding bone, hold osteoprogenitor cells in place, and collect autograft bone within its porous structure. The advantage of the porous structure is the ability to inject polymers and regenerative therapies through the screw. In certain embodiments, stem cell therapy is injected through the screw implant. In such embodiments, the likelihood of failure is reduced.

[0112] In certain embodiments, the surgeon can inject or spray the screw with autologous concentrated stem cells. Without wishing to be bound by theory, as the screw rotates during insertion into the vertebra, the holes in the screw use their built-in trephine to collect an autograft / stem cell mixture internally. Then, the osteoprogenitor cells combine with the concentrated blood stem cells and signal the mutation and replication process, resulting in the formation of more osteoblasts within the screw, followed by a cascade of bone healing guided within and around the screw. In these embodiments, the combination of the (a) osteoconductive (bone grows on its surface), (b) osteoinductive (recruits cells for bone healing), and (c) osteogenic (development and formation of bone) healing cascades of the stem cells improves bone mineral density and supports excellent bone integration and pullout strength.

[0113] In certain embodiments, the patient is a 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 or onto the screw within the pedicle before or after insertion to provide antibiotic delivery in the area. In certain embodiments, the antibiotic is delivered for between two and six weeks. Accordingly, the likelihood of revision due to infection is reduced.

[0114] Manufacture

[0115] The devices disclosed herein can be manufactured using a variety of methods. In some embodiments, manufacturing includes machining, such as subtractive, transformative, or formative manufacturing. In some embodiments, manufacturing includes cutting, grinding, rolling, forming, molding, casting, forging, extruding, swaging, lapping, cold working, or combinations thereof. In some embodiments, manufacturing includes a portion of the device formed by medical machining processes. In some embodiments, the machining uses computer numerical control (CNC) high-speed milling machines, Swiss machining devices, CNC turning with live tools, wire EDM 4th axis, and combinations thereof. In some embodiments, the manufacturing for making a portion of the device includes finishing processes, such as laser marking, tumble blasting, bead blasting, micro-blasting, powder blasting, or combinations thereof.

[0116] In some embodiments, the device is fabricated via additive manufacturing based on a digital rendering and / or data of a selected configuration according to instructions from a computer and a processor.

[0117] In some embodiments, additive manufacturing includes 3-D printing. In some embodiments, additive manufacturing is selected from fused deposition modeling, selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, laminated object manufacturing, stereolithography, and combinations thereof. In some embodiments, additive manufacturing includes rapid prototyping, desktop manufacturing, direct manufacturing, direct digital manufacturing, digital fabrication, instant manufacturing, on-demand manufacturing, or combinations thereof.

[0118] In some embodiments, a portion of the device is fabricated by additive manufacturing and then mechanically attached to the surface of the device, for example, by welding, threading, adhesives, or riveting.

[0119] In one embodiment, the device is configured based on imaging of a patient's anatomy. Suitable imaging techniques include, but are not limited to, X-rays of the patient's anatomy, fluoroscopy, computed tomography (CT), magnetic resonance imaging (MRI), surgical navigation, bone density (DEXA), or available 2-D or 3-D images. Selected configuration parameters for the device are collected, calculated, or determined. Examples of configuration parameters include, but are not limited to, patient anatomy imaging, surgical treatment, historical patient data, statistics, treatment algorithms, implant materials, implant sizes, porosity, and manufacturing methods. In some embodiments, the configuration parameters include implant materials and device porosity based on patient anatomy and surgical treatment. In some embodiments, the porosity is selected. In some embodiments, the configuration parameters of the device are patient-specific. In some embodiments, the configuration parameters of the device are based on a general configuration and are not patient-specific.

[0120] For example, a digital rendering or data of the device is generated for display from a graphical user interface or stored on a database attached to a computer and a processor. In some embodiments, a computer monitor saves, digitally manipulates, or prints a hard copy of the digital rendering or data. In some embodiments, the device is virtually designed on a computer monitor with a CAD / CAM program. In some embodiments, the processor executes code stored on a computer-readable storage medium to execute one or more computer instructions, for example, to transfer instructions to an additive manufacturing device. In some embodiments, the database or computer-readable medium includes RAM, ROM, EPROM, magnetic, optical, digital, electromagnetic, flash drives, semiconductor technologies, or combinations thereof. In some embodiments, the processor instructs the movement and rotation of a motor control device component.

[0121] Regenerative Medicine

[0122] ″Regenerative medicine″ refers to a branch of translational research in tissue engineering and molecular biology that deals with replacing, engineering, or regenerating human cells, tissues, or organs to restore or establish normal function. This field holds the promise of engineering damaged tissues and organs by stimulating the repair mechanisms within the patient to functionally heal previously irreparable tissues or organs. For example, during bone regeneration, new bone formation is mainly influenced by physicochemical cues in the surrounding microenvironment. Tissue cells exist within a complex scaffold physiological microenvironment.

[0123] In certain embodiments, regenerative medicine is combined with the scaffolds or devices disclosed herein. Autograft incorporation occurs in five stages: inflammatory, angiogenic, osteogenic, osteoconductive, and remodeling.

[0124] The inflammation lasts for about 7 to 14 days. The initial injury to the local blood supply and decortication results in a hematoma around the bone graft, into which inflammatory cells invade. Fibroblast-like cells in the inflammatory tissue transform into a fibrovascular matrix. Perioperative anti-inflammatory drugs reduce the fusion rate due to the inflammatory process.

[0125] Vascular buds appear in the fibrovascular matrix, similar to scar tissue formation during angiogenesis. Primary membranous bone forms near the decorticated bone. Subsequently, minimal endochondral ossification and intramembranous ossification occur.

[0126] During osteogenesis from week 4 to week 5, the repair includes increased angiogenesis, resorption of necrotic tissue, and differentiation of osteoblasts and chondroblasts. In particular, stem cells differentiate into osteoblasts. New bone extends towards the central region of the fusion mass. The cortical portion of the graft continues to be resorbed.

[0127] Osteoconduction is characterized by ingrowth into the host bone and creeping substitution. Osteoblasts produce new bone while osteoclasts simultaneously resorb the transplanted bone. A central region of the endochondral interface is observed at the center of the fusion mass, thereby uniting the lower and upper halves of the fusion. Multipotent cells in this central region differentiate into cartilage tissue with less angiogenesis.

[0128] During remodeling from week 6 to week 10, a peripheral cortical rim forms around the fusion. Marrow activity increases, thereby forming secondary cancellous bone. The cortical rim thickens. Trabecular projections extend into the center of the fusion. Remodeling is typically completed one year after device implantation.

[0129] Pseudarthrosis (nonunion) is the main cause of pain after surgery and accounts for 45% - 56% of revisions. Bone fusion is directly related to successful clinical outcomes. In approximately 30% of cases, patients with pseudarthrosis are asymptomatic. Younger individuals have a significantly increased rate of symptomatic pseudarthrosis (43.8 years vs. 52.1 years, p < 0.01).

[0130] In certain embodiments, bone marrow aspirate (BMA) containing allografts replaces autologous bone grafts in single-level revision posterolateral lumbar fusion (PLF). In certain embodiments, bone marrow aspirate containing allografts is more cost-effective than recombinant human bone morphogenetic protein-2 (rhBMP). In certain embodiments, in bone grafting and spinal fusion procedures, marrow-derived cell-rich allografts compared to autologous grafts. In certain embodiments, BMA increases the regenerative potential of corticocancellous allograft bone. When treating unicameral bone cysts, for bone marrow with demineralized bone matrix injection, the healing rate is high (98.7%).

[0131] When introducing elements of the present disclosure or its embodiments, the articles "a", "an", "the", and "said" are intended to indicate the presence of one or more elements. The terms "comprising", "including", and "having" are intended to be inclusive and mean that additional elements may be present in addition to the listed elements.

[0132] 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.

[0133] Although the disclosure described herein is susceptible to various modifications and alternative iterations, specific embodiments thereof have been described in more detail above. However, it should be understood that the detailed description of the compositions is not intended to limit the present disclosure to the specific embodiments disclosed. On the contrary, it should be understood that the present disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the language of the claims.

[0134] Example

[0135] The following examples are included to illustrate certain embodiments of the present disclosure. Those skilled in the art should understand that the techniques disclosed in the examples represent techniques that the inventors have found work well in the practice of the present disclosure. However, according to the present disclosure, those skilled in the art should understand that many changes can be made in the specific examples disclosed without departing from the spirit and scope of the present disclosure, and still obtain the same or similar results. Therefore, all matter is to be construed as illustrative and not restrictive.

[0136] Table 1 - Reference Signs

[0137]

[0138]

[0139] Example 1 - Pedicle Screw

[0140] Reference Figures 2 - 4 , the pedicle screw 200 is 3D printed with titanium. The pedicle screw 200 includes threads 230 disposed around a shaft 240 extending between a proximal end 210 and a distal tip 220. The threads 230 include an external thread form having a leading edge 231 and a trailing edge 232, the leading edge having a front surface 235 and the trailing edge having a rear surface 236. The front surface 235 defines a first opening 251. The rear surface 236 defines a second opening 252. The first opening 251 and the second opening 252 are axially aligned. The pedicle screw 200 has a core 260 extending from the proximal end 210 through the center of the pedicle screw 200 to the distal tip 220. The distal tip 220 includes two cutting members 270, each cutting member having a cutting edge 271.

[0141] Reference Figures 5 - 7 , an embodiment of the pedicle screw 300 is 3D printed with titanium and has the scaffold 280 disclosed herein. The pedicle screw 300 includes threads 230 disposed around a shaft 240 extending between a proximal end 210 and a distal tip 220. The shaft 240 includes two regions of the scaffold 280 exposed to the outer surface of the pedicle screw 300. The threads 230 include an external thread form having a leading edge 231 and a trailing edge 232, the leading edge having a front surface 235 and the trailing edge having a rear surface 236. The front surface 235 defines a first opening 251. The rear surface 236 defines a second opening 252. The first opening 251 and the second opening 252 are axially aligned. The pedicle screw 300 has a core 260 filled with the scaffold 280, the core extending from the proximal end 210 through the center of the pedicle screw 300 to the distal tip 220. The distal tip 220 includes three cutting members 270, each cutting member having a cutting edge 271.

[0142] Reference Figures 8 - 10, Another embodiment of the pedicle screw 400 is 3D printed with titanium and has the scaffold 280 disclosed herein. The pedicle screw 400 includes threads 230 disposed around a shaft 240 extending between a proximal end 210 and a distal tip 220. The shaft 240 includes a region of the scaffold 280 that is exposed to the outer surface of the pedicle screw 400 between the middle seven turns of the threads 230. The threads 230 include an external thread form that has a leading edge 231 and a trailing edge 232, the leading edge having a front surface 235 and the trailing edge having a rear surface 236. The front surface 235 defines a first opening 251. The rear surface 236 defines a second opening 252. The first opening 251 and the second opening 252 are axially aligned. The pedicle screw 400 has a core 260 filled with the scaffold 280 that extends from the proximal end 210 through the center of the pedicle screw 400 to the distal tip 220. The distal tip 220 includes three cutting members 270, each cutting member having a cutting edge 271.

[0143] Reference Figures 11 - 16 , Another embodiment of the pedicle screw 500 is 3D printed with metal and has the scaffold 280 disclosed herein. The pedicle screw 500 includes a cap 510, a saddle 520, and a shaft 540, and a tulip 590 and a pair of pins 595 when present. The cap 510 is configured to be coupled to the saddle 520 via cap threads 513 operably disposed in a saddle groove 523. The saddle 520 is configured to be coupled to the shaft 540. In an embodiment of the pedicle screw having a tulip, the distal tip 220 of the shaft 540 can be disposed through a bottom opening 592 of the tulip 590 and held in place with a pin 595 disposed through a side opening 596 of the tulip 590.

[0144] The pedicle screw 500 includes threads 230 disposed around a shaft 240 extending between a proximal end 210 and a distal tip 220. The shaft 240 includes a region of the scaffold 280 that is exposed to the outer surface of the pedicle screw 500 between the middle thirteen turns of the threads 230. The threads 230 include an external thread form that has a leading edge and a trailing edge, the leading edge having a front surface and the trailing edge having a rear surface. The pedicle screw 500 has a core filled with the scaffold 280 that extends from the proximal end 210 through the center of the pedicle screw 500 to the distal tip 220. The distal tip 220 includes a cutting member 270.

[0145] See Figure 13 and Figure 14 , The cap 510 includes a cap body 514 that has cap threads 513 disposed helically around the outer surface of the cap body 514 between a cap top 511 and a cap bottom 512.

[0146] ReferenceFigure 15 , the saddle 520 includes a saddle body 524 having a saddle top 521, a saddle bottom 522, and at least one saddle groove 523 disposed on an inner surface of the saddle body 524. The at least one saddle groove 523 is configured to receive and operably couple to the cap thread 513. Similarly, the saddle bottom 522 is configured to receive and operably couple to the proximal end 210 of the shaft 540.

[0147] Reference Figure 16 , when present, the tulip-shaped member 590 includes a tulip-shaped body 594 having a top opening 591, a bottom opening 592, at least a pair of tulip-shaped grooves 593 disposed on an inner surface of the tulip-shaped body 594, and a pair of side openings 596 between the at least a pair of tulip-shaped grooves 593 and the bottom opening 592. When the distal tip 220 of the shaft 540 passes through the bottom opening 592 of the tulip-shaped member 590, the at least a pair of tulip-shaped grooves 593 is configured to receive and operably couple to the thread 230 of the shaft 540. After the thread 230 has engaged the at least a pair of tulip-shaped grooves 593, a pair of pins 595 can be operably coupled to the tulip-shaped member 590 through the pair of side openings 596.

[0148] When present, the holes of the bracket 280 facilitate bone ingrowth through the screws. Other materials for making pedicle screws include pre-filled demineralized bone matrix (DBM), pre-filled synthetic DBM, unfilled DBM, and magnesium-injected titanium. During insertion, the built-in channel captures autograft. The screw has a double-ball angle and a low profile. The screw includes a locking cap with reverse-angle threads. The screw can be hollow or non-hollow.

[0149] The length of the screw is between 35 mm and 65 mm, and the diameter is between 4.5 mm and 8.5 mm. The rod acceptance is 5.5 mm.

[0150] The built-in channel for autograft collection enhances the structural integrity of the graft. These excellently resist bone mineral density loss and reduced micromotion. The randomized porosity pattern of the bracket 280 is typical of natural trabecular bone. In addition, the built-in struts provide structural integrity. The pedicle screws 200, 300, 400, 500 are made of cobalt-chromium alloy, titanium, and magnesium-injected titanium.

[0151] The device is tested in cobalt-chromium alloy and meets the American Society for Testing and Materials (ASTM) standards 543, 1798, and 1717.

[0152] ASTM Standard 543 evaluates the resistance of plastic materials to chemical reagents, including castings, thermoformed plastics, cold-molded plastics, laminated resin products, and sheets. Three procedures are given, two under Practice A (immersion testing) and one under Practice B (mechanical stress and reagent exposure under standardized conditions of applied strain). These practices report changes in weight, dimensions, appearance, color, strength, and other mechanical properties. Specified standard reagents are used to establish results on a comparable basis, without excluding other chemical reagents relevant to specific chemical resistance requirements. Various exposure times, stress conditions, and exposure to reagents at elevated temperatures are specified. The type of conditioning (immersion or wet patch / wiping method) depends on the end use of the material.

[0153] ASTM Standard 1798 covers the measurement of the uniaxial static, fatigue strength, and resistance to loosening of the component interconnect mechanisms of spinal arthrodesis implants. This test method provides a means of mechanically characterizing different designs of spinal implant interconnects. Various components and interconnects can be combined for static and fatigue testing of spinal implant constructs. This test method does not address the study of spinal implant constructs or sub-constructs or define the performance levels of spinal implants.

[0154] ASTM Standard 1717 covers materials and methods for static and fatigue testing of spinal implant assemblies in vertebrectomy models. The test materials for combinations of spinal implant assemblies can be specific, depending on the spinal location and the intended method of application to the spine. These test methods provide a basis for mechanical comparison between past, present, and future spinal implant assemblies. They allow 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 performance levels. Instead, these test methods set forth guidelines for methods of applying loads of different types and magnitudes, measuring displacements, determining yield loads, and evaluating the stiffness and strength of spinal implant assemblies. Methods are defined for three types of static load and one fatigue test for comparative evaluation of spinal implant assemblies.

[0155] In some embodiments, the pedicle screws 200, 300, 400, 500 are individually packaged in dual Tyvek TM peel-apart trays.

[0156] 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. Before insertion, the filled or coated screws are allowed to sit for 10 to 15 minutes to allow the material to be absorbed.

[0157] Example 2 - Screw with Two Lumens

[0158] Reference Figures 17 - 19, the screw has discrete porous zones located proximally and distally. The porous structure supports cells integrated into the center of the screw. The screw also supports the independent delivery of cement deployed through perforations at the distal tip of the screw.

[0159] Reference Figure 17 , the screw includes a discrete internal porous grid structure. The double lumen allows for the delivery of cells to the proximal grid and the delivery of cement to the distal grid. The upper lumen communicates with the distal porous (grid) structure from the screw head. Similarly, the lower lumen communicates with the proximal porous (grid) structure from the screw head ( Figure 18 ). The proximal lumen communicates with the proximal porous structure, which contacts cortical bone; the distal lumen communicates with the distal porous structure that contacts cancellous bone. The separating feature divides the bore into a double lumen. ( Figure 19 ).

[0160] In certain embodiments, the screw includes three or more lumens, such as four, five, or six lumens.

[0161] In certain embodiments, the screw includes a thickened head-neck junction below the bore, for example, to reduce the likelihood of rod breakage during screw installation.

[0162] Example 3 - Sheep Study

[0163] In vivo evaluations, ex vivo evaluations, and data from these six sheep studies will determine how this treatment modality affects bone mineral density, polymorphonuclear cells (PMNs), lymphocytes, plasma cells, macrophages giant cells, necrosis, osteoblasts, signs of bone remodeling by osteoclasts, neovascularization, fibrosis, signs of implant degradation, and particulate debris.

[0164] The first specific objective is to determine whether porous pedicle screws promote bone integration and pullout strength compared to the gold standard pedicle screw / rod construct in a sheep model of posterior lumbar interbody fusion. The topography of the 3D-printed porous pattern has a higher adhesion of stem cells to titanium. Additionally, mesenchymal and hematopoietic stem cells have a therapeutic effect on bone. By combining these two approaches, superior results in terms of bone integration and pullout strength can be achieved in the disclosed porous pedicle screws compared to current pedicle screws.

[0165] To this end, bone mineral density (BMD) of 84 vertebral bodies (L1-L6) was measured in six sheep at one week before surgery and at 24 and 36 weeks after surgery. Each subject will receive two separate lumbar interbody fusions (LIFs) at the L2-L3 and L4-L5 joints. L1 and L6 will be untreated controls to compare changes with and without hardware.

[0166] Table 2 - Animal Subjects

[0167]

[0168] In each subject, the titanium intervertebral cage and the bone void filler packed into the intervertebral cage will be placed between the L2-L3 and L4-L5 segments. Then, screws with a diameter of 4.5 mm, 5.5 mm or 6.5 mm and a length of 45 ± 10 mm will be inserted into the right and left pedicles of the L2, L3, L4 and L5 vertebrae. This configuration represents the traditional fusion device and surgical technique. Before insertion, the porous pedicle screws will be sprayed with autologous stem cell concentrate along the length of the screws (treatment).

[0169] All animals will be radiographed for the lumbar spine in vivo immediately after surgery (PO) and at the time of sacrifice. Throughout the study, the animals will be visually evaluated at least once a day. Abnormalities such as signs of infection at the surgical site will be recorded. Thirty-six weeks after surgery, a total of 6 animals will be sacrificed.

[0170] After euthanasia, the lumbar spine sections (L1-L5) will be freshly dissected into individual functional spinal units (FSUs) (i.e., L4-L5) for postmortem evaluation. High-resolution biplane digital radiographs and photographs will be taken at the time of sacrifice after fine dissection in the sagittal and coronal planes. Non-destructive range of motion (ROM) biomechanics will be measured on all samples, including ROM biomechanics under pure moment loads of flexion-extension, lateral bending and axial rotation up to 6.0 N-m, yield range of motion (degrees), construct stiffness (degrees / N-m) and neutral zone (degrees).

[0171] Destructive pedicle screw pullout will be tested. Quasi-static ramp-to-failure testing will yield construct stiffness (N / mm), yield force (N), ultimate failure force (N) and visually observed failure mode (MOD). Destructive pedicle screw unscrewing will be tested for N = 1 of the 4 screws from each test, and the quasi-static torque to unscrew the screw counterclockwise will yield the final torque (Nm).

[0172] Other tests will include micro-computed tomography (MicroCT) of each FSU and associated pedicle screws, quantitative evaluation (bone volume and bone density) of the posterior lumbar fusion (PLF) region, qualitative evaluation of bone ingrowth around the pedicle screws, pedicle screw histology, organ histology and static histomorphometry of the screw target region (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.

[0173] The glass slides are delivered to a board-certified pathologist for histopathological analysis. The pathologist will initially be blinded to the treatment parameters for each site. Then, when applicable, the sections are analyzed and graded according to the grading scheme in Table 3 based on each cell type and response. After all the glass slides are scored for data post-processing, the pathologist will be unblinded so that they can compare the data with the control samples.

[0174] Table 3 - Scoring System for Histological Evaluation of Bone Slices for Cell Type and Response

[0175]

[0176]

[0177] Reference: ISO 10993-6 Annex E (Biological evaluation of medical devices - Part 6: Tests for local effects after implantation)

[0178] The histopathological report will include, but not be limited to, a summary of the methods and materials, a list and qualitative data up to the last time point and conclusions, low-power images, and representative micrographs to illustrate the findings. An unpaired t-test with an alpha (α) value of 0.05 will be performed to determine the statistical significance of the biomechanical and histomorphological measurement outcome parameters. Then, the data will be compared with similar retrospective studies.

[0179] The second specific aim of the study is to show that injecting and spraying autologous concentrated stem cells inside and around pedicle screws is safe. Porous 3D-printed titanium intervertebral cages are usually impregnated with autologous stem cells during the operation. They have been proven to be safe and are the gold standard for helping vertebral fusion after disc removal. The study aims to demonstrate that it can be performed within the vertebrae of sheep to provide confidence in the safety for human clinical trials.

[0180] After sacrifice, the histology will be compared with previous studies to determine the differences and similarities in polymorphonuclear cells (PMN), lymphocytes, plasma cells, macrophages giant cells, necrosis, signs of bone remodeling in osteoblasts +, osteoclasts, neovascularization, fibrosis, signs of implant degradation, and particulate debris. The histological reports will also be compared and contrasted between the control, untreated, and treated sites. An unpaired t-test with an alpha (α) value of 0.05 will be performed to determine the statistical significance of the biomechanical and histomorphological measurement outcome parameters. Injecting autologous stem cells inside and around porous pedicle screws is expected to be safe compared to control screws, untreated screws, and previous studies.

[0181] The third specific aim of this study is to show that the porous pedicle screw has a topography and porous pattern for promoting stem cell adhesion. Human mesenchymal stem cells have the strongest adhesion affinity to the titanium surface, with a porosity between 50% and 70%, a more robust and dense internal cell migration pattern, and high cell viability. Therefore, the porous pattern and topography of the porous pedicle screw should have adhesion similar to that of stem cells.

[0182] After sacrificing the sheep, the screws will be removed from the vertebrae and studied for stem cell adhesion. Cell viability on the implant surface will be performed using the LIVE / DEAD assay. Conditioned media assays will be used to study bone morphogenetic protein 2 (BMP2) expression levels, vascular endothelial growth factor (VEGF), osteocalcin, osteoprotegerin expression, DNA, and alkaline phosphatase activity.

[0183] A correlation will be shown between the cell adhesion of the 3D printed titanium pattern and the porous pedicle screw. The porous pedicle screw exhibits better stem cell adhesion than controls and untreated subjects, as well as an adhesion ratio similar to that of previous studies.

[0184] Example 4 - Sheep Study for Infection

[0185] Another six - animal study will focus on testing the feasibility of injecting a mixture of calcium sulfate and antibiotics as a means of reducing the infection rate after spinal fusion. The primary objectives of this project are to confirm (1) whether the tested pedicle screws contribute to excellent bone integration and pull - out strength compared to the gold - standard pedicle screw / rod construct in a sheep model of posterior lumbar interbody fusion; (2) that injecting a mixture of calcium sulfate and antibiotics can reduce the infection rate after spinal fusion; and (3) that the tested pedicle screws have a topography and porous pattern for injection to support the above - mentioned objectives.

[0186] For the first objective, the rationale is that if a patient has infected bone, the surgeon can protect the hardware by injecting the antibiotic mixture via the device. Through the proposed animal study, we will confirm that in an infected and contained area (e.g., vertebra), the pedicle screw will (1) protect the surgical hardware compared to controls (i.e., confirm that the infection has not spread to the hardware), and (2) reduce the infection in the bone.

[0187] The sheep model was chosen because sheep have the most similar spine to the human spine. The ovine vertebrae are large enough to accommodate the pedicle screws disclosed herein. Smaller animals are not feasible because the screws are too large for their bones.

[0188] Select this sample size to realistically assess feasibility and achieve proof-of-concept within the Phase I scope and timeline. Consistent with the planned objectives, Phase I results will be interpreted as preliminary and tentative conclusions that will be used to inform the expected Phase II, where we can propose a large, controlled, well-powered animal study that evaluates efficacy endpoints in a scientifically rigorous manner.

[0189] The experimental design and methods will be substantially the same as in the sheep study of Example 3 above, including Tables 2 and 3.

[0190] All references, patents, or applications (U.S. or foreign) cited in this application are hereby incorporated by reference as if written in their entirety herein. In the event of any inconsistencies, the materials disclosed herein shall govern.

[0191] From the foregoing description, those skilled in the art can readily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications to adapt it to various uses and conditions.

Claims

1. A medical device, the medical device comprising: A body having a proximal end and a distal tip; A stent in the body, the stent having a porous structure distributed in a proximal mesh in a first region near the proximal end and a distal mesh in a second region near the distal tip; An upper lumen in the proximal end, the upper lumen being in fluid communication with a first opening at the proximal end; And A lower lumen in the distal tip, the lower lumen being in fluid communication with a second opening at the proximal end.

2. The medical device according to claim 1, the medical device further comprising a perforation at the distal tip.

3. The medical device according to claim 2, the medical device being configured to support independent delivery of a cement deployed through the perforation.

4. The medical device according to any one of claims 1 to 3, wherein the porous structure supports cells integrated into the center of the medical device.

5. The medical device according to any one of claims 1 to 4, the medical device being configured to allow delivery of cells to the proximal grid and delivery of cement to the distal grid.

6. The medical device according to any one of claims 1 to 5, wherein the proximal grid or the distal grid or both comprise a discrete internal porous grid structure.

7. The medical device according to any one of claims 1 to 6, wherein the upper lumen contacts cortical bone and the lower lumen contacts cancellous bone.

8. The medical device according to any one of claims 1 to 7, the medical device further comprising a separating feature configured to separate the upper lumen and the lower lumen.

9. The medical device according to any one of claims 1 to 8, the medical device further comprising at least one additional lumen.

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

11. The medical device according to claim 10, the medical device being a pedicle screw.

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

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

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

15. A medical method for treating fractures in a patient in need, the method comprising: The device according to any one of claims 1 to 14 is implanted into the bone of the patient.

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