Spinal Applications of Bioabsorbable Implants

Spine Journal, 2003

Background context: Bioabsorbable implants are commonplace in sports medicine surgeries, especially in shoulder and knee ligamentous reconstruction. Their use is now expanding to the realm of spinal reconstructive surgery. Newer polymers offer reduced incidence of the side effects of aseptic sterile sinus formation and have appropriate resorption time parameters for spine use. These new bioabsorbable materials confer initial and intermediate-term stability that is adequate for stable bony healing in various applications. The majority of human clinical applications in the spine that have been documented involve bone graft harvest site reconstruction, posterior spinal graft containment, anterior interbody reconstruction and anterior cervical and lumbar spine tension band plating. Purpose: The purpose of this review article is to highlight the indications and outcomes of the use of bioabsorbable implants in specific spinal applications. Study design: A comprehensive literature review of the English and non-English literature on bioabsorbable implant technology. Methods: A comprehensive literature review was performed to gather basic science, animal and human data on the use of bioabsorbable implants in spinal surgery. Results: Bioabsorbable implants have demonstrated strength and resorption characteristics commensurate with the physiologic and biomechanical requirements of the human spinal axis. Histologic sampling has demonstrated successful time-patterned resorption accompanied by bony replacement and remodeling of intervertebral cage devices in the animal model. Conclusion: Bioresorbable compounds appear to have a role in specific spinal reconstructive procedures. Their radiolucent nature improves image assessment of fusion healing, and their time-engineered resorption characteristics allow controlled dynamization in interbody and plate applications. Their widespread use and acceptance may increase dramatically as further research and clinical studies report on their safety and efficacy.

Neurosurgical Focus, 2004

The use of bioabsorbable implants in spine surgery is expanding at a rapid pace. These implants are mimicking the roles of traditional metallic devices and are demonstrating similar efficacy in terms of maintaining stability and acting as carriers for grafting substances. Biomechanical studies have demonstrated their ability to stabilize effectively a degenerative cervical and lumbar motion segment. In numerous animal models, researchers have illustrated the ability of bioabsorbable implants to function satisfactorily as an interbody spacer and to achieve satisfactory bone fusion. Investigators have explored various opportunities for these implants to replace their metallic counterparts in clinical studies conducted in humans. The gradual resorption of these implants appears effectively to transfer gradual loads to the grafting substances promoting the biological mechanisms of fusion. Novel uses of bioabsorbable technology are constantly evolving. Their future as a carrier of biological agents such as bone morphogenetic proteins and bone graft extenders, their radiolucency, and their eventual resorption make them an ideal implant for use in spinal degenerative disease.

The Journal of Spinal Surgery, 2014

Biodegradable implants degrade in a biologic environment. The use of bioabsorbable implants in spine surgery is expanding at a rapid pace. Their future as a carrier of biological agents, such as bone morphogenetic proteins and bone graft exten ders, their radiolucency, and their eventual resorption make them an ideal implant for use in spinal degenerative disease. For spine fixation, ideally these implants should have mechanical characteristics equal to those of standard metal implants and would degrade with the healing process, so that fixation is not lost before adequate healing and load is gradually transferred to the healing tissue. Several new experimental bioabsorbable devices are in the process of consideration as spinal implants. These include a myriad of posterior lumbar interbody fusion devices, anterior spinal plates, and a variety of screw and mesh designs.

Orthopaedic surgery, 2014

The clinical outcome of lumbar spinal fusion is correlated with achievement of bony fusion. Improving interbody implant bone on-growth and in-growth may enhance fusion, limiting pseudoarthrosis, stress shielding, subsidence and implant failure. Polyetheretherketone (PEEK) and titanium (Ti) are commonly selected for interbody spacer construction. Although these materials have desirable biocompatibility and mechanical properties, they require further modification to support osseointegration. Reports of extensive research on this topic are available in biomaterial-centric published reports; however, there are few clinical studies concerning surface modification of interbody spinal implants. The current article focuses on surface modifications aimed at fostering osseointegration from a clinician's point of view. Surface modification of Ti by creating rougher surfaces, modifying its surface topography (macro and nano), physical and chemical treatment and creating a porous material wi...

Brain and Spine, 2021

A variety of novel biomaterials are emerging as alternatives to conventional metals and alloys, for use in spinal implants. These promise potential advantages with respect to e.g. elastic modulus compatibility with the host bone, improved radiological imaging or enhanced cellular response to facilitate osseointegration. However, to date there is scarce comparative data on the biological response to many of these biomaterials that would give insights into the relative level of bone formation, resorption inhibition and inflammation. Thus, in this study, we aimed to evaluate and compare the in vitro biological response to standard discs of four alternative biomaterials: polyether ether ketone (PEEK), zirconia toughened alumina (ZTA), silicon nitride (SN) and surface-textured silicon nitride (ST-SN), and the reference titanium alloy Ti6Al4V (TI). Material-specific characteristics of these biomaterials were evaluated, such as surface roughness, wettability, protein adsorption (BSA) and apatite forming capacity in simulated body fluid. The activity of pre-osteoblasts seeded on the discs was characterized, by measuring viability, proliferation, attachment and morphology. Then, the osteogenic differentiation of preosteoblasts was compared in vitro from early to late stage by Alizarin Red S staining and real-time PCR analysis. Finally, osteoclast activity and inflammatory response were assessed by real-time PCR analysis. Compared to TI, all other materials generally demonstrated a lower osteoclastic activity and inflammatory response. ZTA and SN showed generally an enhanced osteogenic differentiation and actin length. Overall, we could show that SN and ST-SN showed a higher osteogenic effect than the other reference groups, an inhibitive effect against bone resorption and low inflammation, and the results indicate that silicon nitride has a promising potential to be developed further for spinal implants that require enhanced osseointegration.

The Journal of the American Academy of Orthopaedic Surgeons

The use of bioabsorbable implants in orthopaedic surgical procedures is becoming more frequent. Advances in polymer science have allowed the production of implants with the mechanical strength necessary for such procedures. Bioabsorbable materials have been utilized for the fixation of fractures as well as for soft-tissue fixation. These implants offer the advantages of gradual load transfer to the healing tissue, reduced need for hardware removal, and radiolucency, which facilitates postoperative radiographic evaluation. Reported complications with the use of these materials include sterile sinus tract formation, osteolysis, synovitis, and hypertrophic fibrous encapsulation. Further study is required to determine the clinical situations in which these materials are of most benefit.

Coatings

In orthopedics, bone fixation imposes the use of implants in almost all cases. Over time, the materials used for the implant have evolved from inert materials to those that mimic the morphology of the bone. Therefore, bioabsorbable, biocompatible, and bioactive materials have emerged. Our study aimed to review the main types of implant materials used in orthopedics and present their advantages and drawbacks. We have searched for the pros and cons of the various types of material in the literature from over the last twenty years. The studied data show that consecrated metal alloys, still widely used, can be successfully replaced by new types of polymers. The data from the literature show that, by manipulating their composition, the polymeric compounds can simulate the structure of the different layers of human bone, while preserving its mechanical characteristics. In addition, manipulation of the polymer composition can provide the initiation of desired cellular responses. Among the ...

Iranian Polymer Journal, 2024

The creation of highly biocompatible advanced materials for use in orthopedics has long been a goal. Because of this need, orthopedic implants have progressed from metals to polymeric composites. Ancient orthopedic implants were mostly metals, but in the present age, advanced new materials in orthopedic surgery and prostheses have broadened the available options. Alternative forms of treatment are becoming increasingly possible with the upgrade of mechanical properties and improved quality of materials. The mechanical performance of advanced material is rationalized including tensile and flexural strength, elastic modulus, and wear resistance to assess their suitability for orthopedic applications. In recent eras, the novelty in research includes the use of reinforced polymer-based composite due to mechanical strength and stress shielding close to real human bone. Also, a comparative analysis of natural and synthetic reinforcement in composites proves that the former is biocompatible, eco-friendly, and economically cost-effective. The bioactivity of composites can be improved by surface modification with bio-coating to promote enhanced biomedical performance. This literature review contains data on different types of materials for prosthetic devices. It outlines mechanical and biological factors favoring material selection, particularly epoxy, for improved physiological functions of the human body, along with economic considerations influencing orthopedic surgery.

Neurosurgical FOCUS, 2004

Both total hip and knee arthroplasty have demonstrated outstanding clinical results. The functional spinal unit composed of the intervertebral disc and facet joints is at least as complex. The intricacies of the coupled motions of the functional spinal unit have made development of an artificial disc a challenge. There have been several failed attempts to create a disc replacement that recapitulates normal motion while providing significant longevity and a low incidence of complications. Better understanding of the biomechanics of the intervertebral disc complex and improvements in implant material have made successful intervertebral disc replacement a likely reality, now that several artificial discs have completed Food and Drug Administration clinical trials. In this manuscript the authors detail the biomaterials used in disc arthroplasty and discuss joint wear and the host response to wear debris.

Journal of Orthopaedic Surgery and Research, 2009

Background: Surgery for disc herniations can be complicated by two major problems: painful degeneration of the spinal segment and re-herniation. Therefore, we examined an absorbable polyglycolic acid (PGA) biomaterial, which was lyophilized with hyaluronic acid (HA), for its utility to (a) re-establish spinal stability and to (b) seal annulus fibrosus defects. The biomechanical properties range of motion (ROM), neutral zone (NZ) and a potential annulus sealing capacity were investigated.