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BACKGROUND:Spinal anesthesia (SA) is a safe and effective alternative to general endotracheal anesthesia (GEA) for lumbar surgery. Foremost among the reasons to avoid GEA is the desire to minimize postoperative cognitive dysfunction (POCD). Although POCD is a complex and multifactorial entity, the risk of its development has been associated with anesthetic modality and perioperative polypharmacy, among others.OBJECTIVE:To determine whether SA reduced polypharmacy compared with GEA in patients undergoing transforaminal lumbar interbody fusion (TLIF).METHODS:Demographic and procedural data of 424 consecutive TLIF patients were extracted retrospectively. Patients undergoing single-level TLIF through GEA (n = 186) or SA (n = 238) were enrolled into our database. Perioperative medications, excluding antibiotic prophylaxis and local anesthetics, were classified into various categories.RESULTS:Patients in the SA cohort received a mean of 4.5 medications vs a mean of 10.5 medications in the GEA cohort (P < .0001). This reduction in perioperative medications remained significant after a multivariate analysis to control for confounders (P < .001 for all variables). The use of vasopressors was significantly reduced in the SA cohort (P < .001), which coincided with a significant reduction in hypotensive episodes (P < .001). Patients undergoing TLIF through GEA had 3.6 times greater odds of experiencing a hypotensive episode intraoperatively (odds ratio = 3.62, 95% CI [2.38-5.49]).CONCLUSION:Spinal anesthesia is associated with a significant decrease in perioperative medications and may confer superior intraoperative hemodynamic stability, which lowers pressor requirements. The decrease of perioperative medications may be an important contribution in reducing the incidence of POCD in patients undergoing TLIFs, although this requires further study.

BACKGROUND:Spinal anesthesia is safe and effective in lumbar surgeries, with numerous advantages over general anesthesia (GA). Nevertheless, 1 major concern preventing the widespread adoption of this anesthetic modality in spine surgeries is the potential for intraprocedural anesthetic failure, resulting in the need to convert to GA intraoperatively.OBJECTIVE:To present a novel additional prone dose algorithm for when a first spinal dose fails to achieve the necessary effect.METHODS:A total of 422 consecutive patients undergoing simple and complex thoracolumbar surgeries under spinal anesthesia were prospectively enrolled into our database. Data were retrospectively collected through extraction of electronic health records.RESULTS:Sixteen of 422 required a second prone dose, of whom 1 refused and was converted to GA preoperatively. After 15 were given a prone dose, only 2 required preoperative conversion to GA. There were no instances of intraoperative conversion to GA. The success rate for spinal anesthesia without the need for conversion rose from 96.4% to 99.5%. In patients who required a second prone dose, there were no instances of spinal headache, deep vein thrombosis, pneumonia, urinary tract infection, urinary retention, readmission within 30 days, acute pain service consult, return to operating room, durotomy, or cerebrospinal fluid on puncture.CONCLUSION:Use of an additional prone dose algorithm was able to achieve a 99.5% success rate, and those who received this second dose did not experience any complications or negative operative disadvantages. Further research is needed to investigate which patients are at increased risk of inadequate analgesia with spinal anesthesia.

BACKGROUND: Triggered electromyography (tEMG) is an intraoperative neuromonitoring technique used to assess pedicle screw placement during instrumented fusion procedures. Although spinal anesthesia is a safe alternative to general anesthesia in patients undergoing lumbar fusion, its use may potentially block conduction of triggered action potentials or may require higher threshold currents to elicit myotomal responses when using tEMG. Given the broad utilization of tEMG for confirmation of pedicle screw placement, adoption of spinal anesthesia may be hindered by limited studies of its use alongside tEMG. OBJECTIVE: To investigate whether spinal anesthesia affects the efficacy of tEMG, we compare the baseline spinal nerve thresholds during lumbar fusion procedures under general vs spinal anesthesia. METHODS: Twenty-three consecutive patients (12 general and 11 spinal) undergoing single-level transforaminal lumbar interbody fusion were included in the study. Baseline nerve threshold was determined through direct stimulation of the spinal nerve using tEMG. RESULTS: Baseline spinal nerve threshold did not differ between the general and spinal anesthesia cohorts (3.25 ± 1.14 vs 3.64 ± 2.16 mA, respectively; P = .949). General and spinal anesthesia cohorts did not differ by age, body mass index, American Society of Anesthesiologists score status, or surgical indication. CONCLUSION: We report that tEMG for pedicle screw placement can be safely and effectively used in procedures under spinal anesthesia. The baseline nerve threshold required to illicit a myotomal response did not differ between patients under general or spinal anesthesia. This preliminary finding suggests that spinal anesthetic blockade does not contraindicate the use of tEMG for neuromonitoring during pedicle screw placement.