5-YEAR REOPERATION RATES AFTER DIFFERENT TYPES OF LUMBAR SPINE SURGERY

Study Design. Population-based cohort study of Washington State patien ts who underwent lumbar spine surgery for degenerative conditions in 1 988. Objectives. To compare complications and reoperation rates during the 5-year period after surgery between patients who have undergone l umbar spine fusion surgery and those who have undergone laminectomy or discectomy alone. Summary of Background Data. Spinal fusion is associ ated with wider surgical exposure, more extensive dissection, and long er operative times than lumbar surgery without fusion, and previous st udies have shown higher complication rates and hospital charges associ ated with these more complex procedures. In elderly patients, spinal f usion operations were associated with higher mortality rates than lami nectomy or discectomy alone, and reoperation rates were not lower. In the current study, reoperations, mortality, and complications followin g lumbar spine surgery were examined for the general population. Metho ds. A statewide hospital discharge database was used to identify all W ashington patients who underwent spine surgery in 1988 and to determin e the rate of reoperation during the subsequent 5 years. Administrativ e records also were used to identify complications, mortality, and hos pital charges associated with the operations. Unadjusted complication and reoperation rates for the groups were compared using chi-square st atistics. Adjusted rates were compared using logistic regression and p roportional hazards (Cox) regression after controlling for age, gender , prior spine surgery, diagnosis, comorbidity, type of surgery, and co verage by Workers' Compensation. Results. Of 6376 patients who underwe nt lumbar surgery for degenerative conditions in Washington in 1988, 1 041 (16%) had operations involving spine fusion. Diagnoses of degenera tive disc disease or possible instability were more frequent among pat ients undergoing fusion surgery, whereas herniated discs were more fre quent among those undergoing discectomy or laminectomy alone. Complica tions were recorded in 18% of fusion patients and 7% of nonfusion pati ents (P < 0.01), but mortality rates did not differ. Unadjusted reoper ation rates over the 5-year period were greater for patients who under went fusion than for patients who underwent nonfusion surgery (18% vs. 15%, respectively), but after adjustment for baseline characteristics , fusion patients had only a slightly greater (and nonsignificant) ris k of reoperation (relative risk 1.1, confidence interval .9-1.3). Conc lusion. As in previous studies, complications in the current study occ urred more frequently among patients who underwent lumbar spine fusion than among those who underwent laminectomy or discectomy alone. Reope rations were at least as frequent after fusion, but the authors could not assess treatment efficacy in terms of pain relief or improved func tion. Although the characteristics of patients undergoing fusion diffe red from those undergoing a laminectomy or discectomy alone, there app eared to be sufficient overlap in the clinical populations to warrant closer scrutiny of the safety, efficacy, and indications for spinal fu sions, preferably in randomized trials.