Freeze-Dried Allograft for Posterior Spinal Fusion in Patients With Neuromuscular Spinal Deformities

Abstract

Study Design. The effectiveness and safety of freeze-dried allograft for posterior spinal fusion in patients with neuromuscular disorders were evaluated retrospectively. Summary of Background Data. Because the harvest of an adequate quantity or autogenous bone graft from patients with neuromuscular deformity who have instrumentation and fusion to the pelvis is difficult at best, an alternative graft source usually is needed. Allograft bone, most commonly processed fresh-frozen or freeze-dried, has been used frequently for posterior spinal fusion in patients with neuromuscular deformity. However, a relatively high risk of infection and pseudarthrosis has been reported for this procedure. Methods. Forty percent with neuromuscular deformity with an average age at the time of surgery of 14 years and 2 months range 5 years, 4 months to 23 years, 8 months) met the inclusion criteria. All of these patients underwent more than 2 years of follow-up evaluation. They were evaluated for rates of infection, pseudoarthrosis, and transmissible disease. Results. Thirty-eight patients had solid fusion at the most recent follow-up visit. Definite pseudarthrosis was detected in one patient (2.6% of the study group), which was treated successfully. Another patient's (2.5%) spinal curve progression of more than 10°and rod breakage led the authors to diagnose a probable pseudarthrosis. She had a stable spine that did not require revision at 68 months after surgery. For the 32 patients who underwent posterior surgery only, the pseudarthrosis rate was 3.1%. There were no acute deep wound infections. Superficial infection occurred in two patients (5%) and delayed deep sterile drainage in one patient (2.5%). All cases of infection resolved with appropriate management. Delayed deep wound infection developed in one patient (2.5%) as a result of staphylococcus coagulase negative at 34 months after surgery. Successful treatment has consisted of implant removal, debridement, and appropriate antibiotics. Transmissible disease attributable to allograft has not been detected to date. Conclusion. Freeze-dated allograft fusion is a reliable and effective method for posterior spinal fusion in the patients with neuromuscular deformity.