✓ With the increasing use of bioabsorbable implants in a variety of clinical conditions, potential advantages in selected spinal applications are now being realized. Newer polymers with biomechanical properties relevant to the requirements of specific spinal implants and resorption rates appropriate for specific spinal applications are being developed. These new materials offer the necessary biomechanical stability of conventional spinal implants without the sequelae associated with metallic implants such as long-term loosening, implant migration, and imaging interference. At this time, the majority of clinical applications for these new polymers have involved tension band plating in the lumbar and anterior cervical spine, anterior spinal interbody reconstruction, posterior bone graft containment, and bone graft harvest site reconstruction.
Alexander R. Vaccaro and Luke Madigan
Matthew M. Robbins, Alexander R. Vaccaro and Luke Madigan
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.
Alexander R. Vaccaro, Matthew M. Robbins, Luke Madigan, Todd J. Albert, William Smith and Alan S. Hilibrand
In this pilot study the authors assessed the efficacy of bioabsorbable interbody spacers in the treatment of cervical degenerative disease. Metallic cages or interbody spacers have been widely used in the treatment of degenerative and traumatic cervical disease. Bioabsorbable technology has been used to develop a resorbable cage that can eliminate the complications and drawbacks seen with the use of traditional metallic implants. In general clinical practice bioabsorbable implants have shown the ability to degrade safely while demonstrating optimal imaging characteristics as a result of their radiolucency, and these devices eliminate stress shielding by their gradual dissolution.
This study is a retrospective evaluation of charts and x-ray films obtained in the first eight patients who underwent an anterior cervical decompression and fusion procedure with placement of a bioabsorbable interbody spacer and anterior cervical plate. All patients were treated in one surgeon's practice and had a minimum follow-up period of at least 6 months. At a follow-up interval of approximately 7 months, five patients exhibited an excellent result and three had a good result; no patient was noted to have a satisfactory or poor outcome according to the Odom criteria at their most recent follow-up visit. Seventeen (94%) of 18 grafted levels appeared to be solidly fused. One patient experienced a perisurgical complication consisting of a symptomatic hematoma, which was successfully drained.
Bioabsorbable interbody spacers appear to be a safe and effective interbody implant in terms of clinical outcome and radiographically confirmed healing.