Management of symptomatic lumbar pseudarthrosis with anteroposterior fusion - A functional and radiographic outcome study

Study Design. An independent retrospective review of 37 patients undergoing 39 anteroposterior lumbar fusions for lumbar pseudarthrosis repair between 1984 and 1990. Objectives. To evaluate radiographically and functionally the results of the combined anteroposterior fusion for the management of symptomatic lumbar pseudarthrosis, and to assess risk factors for functional failure after the procedure. Summary of Background Data. Most reported techniques of pseudarthrosis repair involve posterior fusion with no instrumentation, posterior fusion with instrumentation, OF anterior fusion alone. The results of lumbar pseudarthrosis repair are poor. Fusion rates range from 30% to 70%, with only a 30% to 50% rate of functional success. Methods. Thirty-nine procedures were assessed in 37 patients. The outcomes were assessed radiographically (solid fusion vs. pseudarthrosis) and functionally (success vs. failure). Radiographs were assessed at follow-up examination for consolidation of fusion anteriorly and posteriorly. Functional outcome was graded by using multiple instruments, including data from chart review and the follow-up outcome questionnaire. A functional failure score that took into account 10 items was developed. Results, In this patient population (37 patients, 59% with a smoking history, 71% with compensation or legal claims), there was a 10% pseudarthrosis rate. Pseudarthrosis was defined when one or more levels were involved and when it occurred anteriorly and posteriorly. In 12 patients (35%), the outcome was rated as functional failure. The presence of one or more abnormal neurologic findings and significant narcotic use before surgery significantly increased the chance of a patient's outcome being functional failure, Workmen's Compensation or legal status before surgery also increased the chance of functional failure, though this correlation was not statistically significant. Conclusions. A combined anterior and posterior approach for the management of symptomatic lumbar pseudarthrosis is a viable alternative to posterior fusion alone. In fact, this procedure affords a higher fusion rate based on radiographic assessment. Functional failure rates may be decreased by using caution for those patients using narcotics regularly before surgery or in those with unexplained preoperative neurologic abnormal findings.