Bio-Derived Apatite As a Bone Graft for Vertebral Trauma.

INTRODUCTION: Traumatic spinal injury presents the potential for significant morbidity and mortality, and posterior fixation and fusion with bone grafts is a primary treatment for many vertebral fractures. While iliac crest autograft (ICBG) is considered the gold standard in bone grafting, this carries risks of morbidity at the donor site as well as prolonging surgery time. Bone graft substitutes (BGS) may provide a viable alternative to autograft but there is little published data concerning its use in trauma. Therefore, we conducted this retrospective review to evaluate the outcomes for fusion among patients who have received a BGS during posterolateral fusion (PLF) for vertebral trauma. MATERIALS AND METHODS: This was a retrospective, consecutive patient cohort. Over a six-month period, we identified 27 patients who had undergone PLF for spine trauma and in whom a BGS comprised of bovine-derived apatite was used. All patients had followed the standard of care. The postoperative plain film radiographs at three, six, 12, and (optionally) 24 months were independently assessed by an orthopedic surgeon who was not affiliated with the hospital. RESULTS: We documented a radiographically observed fusion rate of 85% and a successful treatment rate of 92%. There were no adverse events related to the BGS. Patients who received a BGS with ICBG spent significantly longer in surgery than other patients. There were no adverse events related to the BGS. CONCLUSIONS: The spondylodesis rate following surgery in which the BGS was used in PLF, whether alone, mixed with local bone, or mixed with ICBG is comparable to the rates that have been reported for iliac crest autograft in these indications. The data indicates that the BGS provides a useful adjunct in PLF for the treatment of traumatic spine vertebral injuries. The use of BGS also allows for shorter time in surgery, which may reduce resource utilization and thus lower the total costs of the procedure. CLINICAL RELEVANCE: Posterolateral fusion can be obtained with the use of a bio-derived BGS while reducing the time in surgery by avoiding the second procedure necessary to harvest ICBG. This may be advantageous in cases where the surgeon wishes to minimize operating time or when the availability of autograft is limited.

Minimum four-year follow-up of spinal stenosis with degenerative spondylolisthesis treated with decompression and dynamic stabilization.

STUDY DESIGN: Prospective clinical study. OBJECTIVE: To test whether posterior dynamic stabilization in situ with Dynesys (Zimmer Spine, Minneapolis, MN) can maintain enough stability to prevent progression of spondylolisthesis in long-term follow-up. SUMMARY OF BACKGROUND DATA: In spinal stenosis with degenerative spondylolisthesis, decompression and fusion are widely recommended. However, drawbacks of fusion remain length of surgery, blood loss, possible adjacent segment disease, errant instrumentation, nonunion, and pain at the bone donor site. The Dynesys system was introduced to stabilize the spine without adding bone graft for fusion. Excellent 2 years results have been reported. METHODS: Twenty-six consecutive patients (mean age, 71 years) with symptomatic lumbar spinal stenosis and degenerative spondylolisthesis underwent interlaminar decompression and stabilization with Dynesys. Patients were evaluated clinically and radiologically after a minimum follow-up of 4 years. RESULTS: Nineteen of 26 patients could be evaluated with a mean follow-up of 52 months (range, 48-57 months). Pain on VAS and walking distance improved significantly (P < 0.001) at 2 years and remained unchanged at 4 years follow-up. Radiographically, spondylolisthesis did not progress and the motion segments remained stable, even in the 3 patients who showed slight screw-loosening at 2 and 4 years follow-up. One patient showed screw breakage with low back pain and motion at the instrumented level in flexion/extension views. At 4 years follow-up, 47% of the patients showed some degeneration at adjacent levels. Overall, patient satisfaction remained high as 95% would undergo the same procedure again. CONCLUSION: In elderly patients with spinal stenosis and degenerative spondylolisthesis, decompression and dynamic stabilization lead to excellent clinical and radiologic results. It maintains enough stability to prevent progression of spondylolisthesis. Because no bone grafting is necessary, donor site morbidity, which is one of the main drawbacks of fusion is eliminated. However, the degenerative disease still is progressive and degeneration at adjacent motion segments remains a problem.