Posterior Lumbar Interbody Fusion Using Nonresorbable Poly-Ether-Ether-Ketone Versus Resorbable Poly-l-Lactide-Co-d,l-Lactide Fusion Devices: A Prospective, Randomized Study to Assess Fusion and Clinical Outcome

Study Design. A prospective randomized clinical study. Objective. To assess fusion, clinical outcome, and complications. Summary of Background Data. Resorbable poly-l- lactide-co-d,l-lactide (PLDLLA) cages intended to aid spinal interbody fusion have been introduced into clinical practice within the last decade. Although early case series show promising results with respect to fusion rate, worries persist with regards to efficacy and potential risks of early failure of these implants. Despite widespread clinical application this is the first randomized prospective study to assess clinical and radiologic outcomes of PLDLLA cage compared with a traditionally applicable counterpart. Methods. Twenty-six patients were randomly assigned to undergo instrumented posterior lumbar interbody fusion whereby either a nonresorbable poly-ether-ether-ketone (PEEK) cage or a resorbable PLDLLA cage was implanted to aid fusion. Fusion rate, subsidence, and clinical outcome based on visual analog scale scores for leg pain and back pain, as well as Oswestry Disability Index and SF-36 questionnaires were documented and analyzed. Complications and adverse events were recorded. Results. Fusion rate was significantly higher with the PEEK cage compared with PLDLLA cage (Fisher exact test, P = 0.0302). Rate of subsidence was significantly higher with the PLDLLA cage compared to PEEK cage (Fisher exact test, P = 0.0414). The PEEK group demonstrated greater improvement in the Oswestry Disability Index compared with the PLDLLA group (Fisher exact test, P = 0.1414). Two cases of mild to moderate osteolysis were seen in the PLDLLA group. Conclusion. Our results strongly suggest that PLDLLA cage proffers a lower rate of fusion compared with PEEK cage, and also confirms that the efficacy of PLDLLA cage in enhancing interbody spinal fusion is yet to be established. The higher rate of subsidence and occurrence of osteolysis seen in association with PLDLLA cages in this study remain worrisome.

[1]  D. Polly,et al.  Computerized tomography evaluation of a resorbable implant after transforaminal lumbar interbody fusion. , 2004, Neurosurgical focus.

[2]  T. Smit,et al.  Time-Dependent Mechanical Strength of 70/30 Poly(l,dl-lactide): Shedding Light on the Premature Failure of Degradable Spinal Cages , 2008, Spine.

[3]  T. Lowe,et al.  Bioresorbable polymer implants in the unilateral transforaminal lumbar interbody fusion procedure. , 2002, Orthopedics.

[4]  Martijn van Dijk,et al.  The Effect of Cage Stiffness on the Rate of Lumbar Interbody Fusion: An In Vivo Model Using Poly(L-Lactic Acid) and Titanium Cages , 2002, Spine.

[5]  B. Walters,et al.  Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 4: radiographic assessment of fusion. , 2005, Journal of neurosurgery. Spine.

[6]  M. Rousseau,et al.  Circumferential Arthrodesis Using PEEK Cages at the Lumbar Spine , 2007, Journal of spinal disorders & techniques.

[7]  E H Burger,et al.  In vitro and in vivo degradation of bioabsorbable PLLA spinal fusion cages. , 2002, Journal of biomedical materials research.

[8]  S. Glassman,et al.  Reliability and agreement between fine-cut CT scans and plain radiography in the evaluation of posterolateral fusions. , 2007, The spine journal : official journal of the North American Spine Society.

[9]  Martijn van Dijk,et al.  Bioabsorbable Poly-L-Lactic Acid Cages for Lumbar Interbody Fusion: Three-Year Follow-up Radiographic, Histologic, and Histomorphometric Analysis in Goats , 2002, Spine.

[10]  P. V. van Diest,et al.  Four-year follow-up of poly-L-lactic Acid cages for lumbar interbody fusion in goats. , 2005, Journal of long-term effects of medical implants.

[11]  W. Sears.  Posterior lumbar interbody fusion for degenerative spondylolisthesis: restoration of sagittal balance using insert-and-rotate interbody spacers. , 2005, The spine journal : official journal of the North American Spine Society.

[12]  A. Vaccaro,et al.  Instrumented Transforaminal Lumbar Interbody Fusion With Bioresorbable Polymer Implants and Iliac Crest Autograft , 2005, Spine.

[13]  C. Branch,et al.  Novel bioabsorbable interbody fusion spacer-assisted fusion for correction of spinal deformity. , 2003, Neurosurgical focus.

[14]  T. Lanman,et al.  Lumbar interbody fusion after treatment with recombinant human bone morphogenetic protein-2 added to poly(L-lactide-co-D,L-lactide) bioresorbable implants. , 2004, Neurosurgical focus.

[15]  I. Lieberman,et al.  Lumbar intervertebral body fusion cages: histological evaluation of clinically failed cages retrieved from humans. , 2004, The Journal of bone and joint surgery. American volume.

[16]  T. H. Smit,et al.  Application of polylactides in spinal cages: Studies in a goat model , 2006, Journal of materials science. Materials in medicine.

[17]  Vijay K. Goel,et al.  Biomechanical Rationale for Using Polyetheretherketone (PEEK) Spacers for Lumbar Interbody Fusion–A Finite Element Study , 2006, Spine.

[18]  D. Couture,et al.  Posterior lumbar interbody fusion with bioabsorbable spacers and local autograft in a series of 27 patients. , 2004, Neurosurgical focus.

[19]  T. Smit,et al.  The use of poly-L-lactic acid in lumbar interbody cages: design and biomechanical evaluation in vitro , 2003, European Spine Journal.

[20]  K. Wood,et al.  Prospective assessment of cervical fusion status: plain radiographs versus CT-scan. , 2006, Acta orthopaedica Belgica.

[21]  J. Coe.  Instrumented transforaminal lumbar interbody fusion with bioabsorbable polymer implants and iliac crest autograft. , 2004, Neurosurgical focus.

[22]  T. Tullberg,et al.  Failure of a Carbon Fiber Implant: A Case Report , 1998, Spine.

[23]  K. Das,et al.  Comparison of polyetheretherketone cages with femoral cortical bone allograft as a single-piece interbody spacer in transforaminal lumbar interbody fusion. , 2006, Journal of neurosurgery. Spine.