Bioabsorbable anterior cervical plate fixation for single-level degenerative disorders: early clinical and radiographic experience

BACKGROUND CONTEXT: Increased fusion rates have been reported with the addition of an anterior cervical plate (ACP) to anterior cervical discectomy and fusion (ACDF). Bioabsorbable implants have become increasingly used in orthopedic and spine surgical procedures. There are limited data regarding the outcomes of bioabsorbable ACP (bACP) with ACDF. PURPOSE: To compare the clinical and radiographic outcomes of patients undergoing ACDF for single-level degenerative disorders with a bACP versus a conventional metal ACP (mACP). STUDY DESIGN: Retrospective comparative cohort study. PATIENT SAMPLE: Thirty-one patients undergoing ACDF for a single-level degenerative disorder (ie, disc herniation or spondylotic neural compression). OUTCOME MEASURES: Incidence of early (within 2 weeks) complications, postoperative sagittal alignment, Odom's criteria, and pseudarthrosis rate. METHODS: The authors retrospectively reviewed the results of a consecutive series of patients undergoing ACDF for symptomatic single-level disc herniation or spondylotic neural compression with either a bACP or an mACP over a 3-year period. Operative notes, clinical charts, and radiographs were analyzed. Radiographic outcomes were assessed for intersegmental alignment, graft subsidence, fusion rate, prevertebral soft-tissue shadow, and graft containment. Clinical outcome was evaluated by Odom's criteria. RESULTS: Fourteen patients underwent ACDF with a bACP and 15 with an mACP. Radiographic outcomes at the most recent follow-up demonstrated pseudarthrosis in 4 of 14 patients (29%) in the bACP group and 0 of 15 patients in the mACP group. Graft extrusion and anterior displacement was present in three of four pseudarthroses (75%). Comparing preoperative and final radiographs, cervical lordosis was maintained at the operative segment in only 3 of 14 bACP patients (21%) compared with 8 of 15 patients (53%) in the mACP group. The mean Cobb angle was 2.4 degrees +/- 1.9 degrees lordosis in the mACP group and -2.7 degrees +/- 2.5 degrees kyphosis in the bACP group (p=.12). In the mACP group, 14 of 15 patients had good or excellent results. In the bACP group, only 7 of 14 patients had good or excellent results. CONCLUSIONS: Bioabsorbable ACP fixation was associated with a high rate of graft extrusion and early loss of intersegmental cervical alignment. Inferior clinical outcomes were observed in patients in the bACP group compared with the mACP group. Based on these findings, continued use of the bACP used in this study cannot be recommended. (C) 2011 Elsevier Inc. All rights reserved.