Failure of external spinal skeletal fixation to improve predictability of lumbar arthrodesis.

BACKGROUND: Whether lumbar arthrodesis can relieve isolated low-back pain in the absence of focal neurological findings or instability is unclear. The results of published studies are also inconsistent with regard to whether temporary back-pain relief with external spinal skeletal fixation can predict lasting back-pain relief after arthrodesis. This report presents the results, with regard to clinical benefit and complications, of more than 100 external spinal skeletal fixation procedures undertaken as a prelude to lumbar arthrodesis. METHODS: The records of all patients who underwent external spinal skeletal fixation between 1989 and 1999 were reviewed with attention to perioperative complications, pain relief from the test procedure, the clinical benefit from a subsequent arthrodesis, and the functional status after the arthrodesis. Analyzed data included the frequency of neurological complications and infections and the benefit (Prolo score) after staged spinal arthrodesis in patients who underwent arthrodesis after temporarily experiencing pain relief with the test procedure. RESULTS: A total of 103 external spinal skeletal fixation procedures were undertaken. Neurological complications occurred in two procedures (2%); one resulted in permanent sciatica. Infections occurred in five patients (5%). Sixty patients experienced pain relief during the external fixation test, but only twenty-seven of forty-nine patients who went on to have an arthrodesis and had sufficient follow-up reported that they were doing well at a minimum of one year later. In no case did the external spinal skeletal fixation procedure cause a permanent increase in low-back pain. CONCLUSIONS: On the basis of this analysis, external spinal skeletal fixation should not be used as a predictor of pain relief after lumbar arthrodesis.