Spine. 2009 May 4; Thalgott JS, Fogarty ME, Giuffre JM, Christenson SD, Epstein AK, Aprill CSTUDY DESIGN.: Prospective, randomized clinical trial from a single surgeon's patient population. OBJECTIVE.: The purpose of this study is to compare the outcomes and fusion rates of an anterior lumbar interbody fusion (ALIF) procedure when 2 different preservation methods of the femoral ring allograft (FRA) are used. SUMMARY OF BACKGROUND DATA.: FRA can be stored via freeze-drying (FD) or freezing (FZ). In a previous biomechanical PLIF model, FZ cancellous allograft failed at an average load 50% less than FD cancellous allograft. Despite this finding, there is no evidence to support which preservation method is more effective at achieving solid fusion in ALIF procedures. METHODS.: Fifty ALIF patients received either FZ or FD FRA. Patients were observed for a minimum of 24 months. Outcome measures included complications, fusion status, implant intactness, 1 to 10 pain scale scores, Oswestry Disability Index (ODI), and SF-36 scores. RESULTS.: Univariate comparisons for grafting material are as follows: Average ODI-FD: 46.05 +/- 16.7, FZ: 39.24 +/- 23.65, P = 0.296. Average Physical Component Summary from SF36-FD: 33.47 +/- 10.12, FZ: 39.76 +/- 11.50, P = 0.074. Average 1 to 10 back pain with medication-FD: 3.47 +/- 2.59, FZ: 2.95 +/- 2.48, P = 0.527. ODI scores improved more than 10 points in 62.5% of patients. SF-36 Physical Component Summary scores improved more than 10 points in 27.5% of patients. Back pain with medication scores improved 2 or more points in 60.5% of patients. Seven patients required revision for psuedarthrosis (FD: 6, FZ: 1, P = 0.026). Fusion was achieved in 40 levels (71.4%). The freeze-dried graft had a higher likelihood of pseudarthrosis (P = 0.026). CONCLUSION.: When the results are considered in terms of clinical outcomes, the 2 methods of graft preservation perform with few statistically significant differences. Radiographic analysis showed that the freeze-dried graft had a higher likelihood of pseudarthrosis.
