A lack of information exists on the relationship between preoperative epidural spinal injections and outcomes after spine surgery. There is concern that injections might cause local changes, increasing the infection risk and surgical difficulty. Therefore, the authors explored the relationship between preoperative spinal injections and postoperative outcome.
The cohort was comprised of patients who underwent thoracic and/or lumbar arthrodesis during the years 2007–2010 and had complete (preoperatively and 3 months postoperatively) outcome scores. Patients’ clinical courses were reviewed to determine the occurrence of major complications within a 30-day postoperative period. Patient-perceived outcomes were evaluated using the Oswestry Disability Index (ODI) and the SF-12 (12-Item Short Form Health Survey): mental component summary (MCS) and physical component summary (PCS) scores. Analyses were based on exposure to injections and were performed using chi-square exact tests and paired and unpaired t-tests.
Two hundred eighty patients met the inclusion criteria: 117 patients (41.8%) received and 163 patients (58.2%) did not receive preoperative epidural spinal injections. Overall, the likelihood of complication did not differ with respect to exposure (13.7% injection vs 11.7% noninjection); however, injected patients observed a 7.4-fold risk of developing surgical wound complications over noninjected patients (5.1% vs 0.6%, p = 0.02).
Patient-perceived outcomes measures demonstrated no differences between groups. Three months postoperatively, the MCS and ODI scores were similar (MCS: 49.6 ± 11.6 injection vs 47.4 ± 12.8 noninjection; ODI: 35.8 ± 18.0 vs 34.4 ± 19.1). MCS or ODI score improvement (preoperatively compared with 3 months postoperatively) did not vary between groups. Injected patients maintained a 2-point lower PCS score at entry and 3 months postoperatively as compared with noninjected peers (entry: 27.6 ± 8.2 injection vs 29.5 ± 9.3 noninjection, p = 0.09; 3 months: 33.3 ± 8.6 vs 35.7 ± 9.0, p = 0.03); the PCS score improvements between injected and noninjected groups were similar (5.7 ± 9.9 vs 6.2 ± 9.7).
Patients exposed to preoperative epidural injections had similar complication rates to those who never received a spinal injection. However, they had a greater risk of developing wound complications. These complications had no effect on short-term improvements in outcome measures.