Spinal anesthesia in awake surgical procedures of the lumbar spine: a systematic review and meta-analysis of 3709 patients

OBJECTIVE Awake surgery has previously been found to improve patient outcomes postoperatively in a variety of procedures. Recently, multiple groups have investigated the utility of this modality for use in spine surgery. However, few current meta-analyses exist comparing patient outcomes in awake spinal anesthesia with those in general anesthesia. Therefore, the authors sought to present an updated systematic review and meta- analysis investigating the utility of spinal anesthesia relative to general anesthesia in lumbar procedures. METHODS Following a comprehensive literature search of the PubMed and Cochrane databases, 14 clinical studies were included in our final qualitative and quantitative analyses. Of these studies, 5 investigated spinal anesthesia in lumbar discectomy, 4 discussed lumbar laminectomy, and 2 examined interbody fusion procedures. One study investigated combined lumbar decompression and fusion or decompression alone. Two studies investigated patients who underwent discectomy and laminectomy, and 1 study investigated a series of patients who underwent transforaminal lumbar interbody fusion, posterolateral fusion, or decompression. Odds ratios, mean differences (MDs), and 95% confidence intervals were calculated where appropriate. RESULTS A meta- analysis of the total anesthesia time showed that time was significantly less in patients who received spinal anesthesia for both lumbar discectomies (MD -26.53, 95% CI -38.16 to -14.89; p = 0.00001) and lumbar laminectomies (MD -11.21, 95% CI -19.66 to -2.75; p = 0.009). Additionally, the operative time was significantly shorter in patients who underwent spinal anesthesia (MD -14.94, 95% CI -20.43 to -9.45; p < 0.00001). Similarly, when analyzing overall postoperative complication rates, patients who received spinal anesthesia were significantly less likely to experience postoperative complications (OR 0.29, 95% CI 0.16-0.53; p < 0.0001). Furthermore, patients who received spinal anesthesia had significantly lower postoperative pain scores (MD -2.80, 95% CI -4.55 to -1.06; p = 0.002). An identical trend was seen when patients were stratified by lumbar procedures. Patients who received spinal anesthesia were significantly less likely to require postoperative analgesia (OR 0.06, 95% CI 0.02-0.25; p < 0.0001) and had a significantly shorter hospital length of stay (MD -0.16, 95% CI -0.29 to -0.03; p = 0.02) and intraoperative blood loss (MD -52.36, 95% CI -81.55 to -23.17; p = 0.0004). Finally, the analysis showed that spinal anesthesia cost significantly less than general anesthesia (MD -226.14, 95% CI -324.73 to -127.55; p < 0.00001). CONCLUSIONS This review has demonstrated the varying benefits of spinal anesthesia in awake spine surgery relative to general anesthesia in patients who underwent various lumbar procedures. The analysis has shown that spinal anesthesia may offer some benefits when compared with general anesthesia, including reduction in the duration of anesthesia, operative time, total cost, and postoperative complications. Large prospective trials will elucidate the true role of this modality in spine surgery.