Inadequate Spinal Anesthesia in Lumbar Spine Surgery Is Related to Volume of the Thecal Sac.

BACKGROUND: Spinal anesthesia (SA) is used in lumbar surgery, but initial adequate analgesia fails in some patients. In these cases, spinal redosing or conversion to general endotracheal anesthesia is required, both of which are detrimental to the patient experience and surgical workflow. METHODS: We reviewed cases of lumbar surgery performed under SA from 2017-2021. We identified 12 cases of inadequate first dose and then selected 36 random patients as controls. We used a measurement tool to approximate the volume of the dural sac for each patient using T2-weighted sagittal magnetic resonance imaging sequences. RESULTS: Patients who had an inadequate first dose of anesthesia had a significantly larger dural sac volume, 22.8 ± 7.9 cm3 in the inadequate dose group and 17.4 ± 4.7 cm3 in controls (P = 0.043). The inadequate dose group was significantly younger, 54.2 ± 8.8 years in failed first dose and 66.4 ± 11.9 years in controls (P = 0.001). The groups did not differ by surgical procedure (P = 0.238), level (P = 0.353), American Society of Anesthesia score (P = 0.546), or comorbidities. CONCLUSIONS: We found that age, larger height, and dural sac volume are risk factors for an inadequate first dose of SA. The availability of spinal magnetic resonance imaging in patients undergoing spine surgery allows the preoperative measurement of their thecal sac size. In the future, these data may be used to personalize spinal anesthesia dosing on the basis of individual anatomic variables and potentially reduce the incidence of failed spinal anesthesia in spine surgery.

Spinal Anesthesia Reduces Perioperative Polypharmacy and Opioid Burden in Patients Over 65 Who Undergo Transforaminal Lumbar Interbody Fusion.

BACKGROUND: Polypharmacy and opioid administration are thought to increase the risk of postoperative cognitive dysfunction and delirium in elderly patients. Spinal anesthesia (SA) holds potential to reduce perioperative polypharmacy in spine surgery. As more geriatric patients undergo spine surgery, understanding how SA can reduce polypharmacy and opioid administration is warranted. We aim to compare the perioperative polypharmacy and dose of administered opioids in patients ≥65 years who undergo transforaminal lumbar interbody fusion (TLIF) under SA versus general anesthesia (GA). METHODS: A retrospective analysis of 200 patients receiving a single-surgeon TLIF procedure at a single academic center (2014-2021) was performed. Patients underwent the procedure with SA (n = 120) or GA (n = 80). Demographic, procedural, and medication data were extracted from the medical record. Opioid consumption was quantified as morphine milligram equivalents (MME). Statistical analyses included χ2 or Student's t-test. RESULTS: Patients receiving SA were administered 7.45 medications on average versus 12.7 for GA patients (P < 0.001). Average perioperative opioid consumption was 5.17 MME and 20.2 MME in SA and GA patients, respectively (P < 0.001). The number of patients receiving antiemetics and opioids remained comparable postoperatively, with a mean of 32.2 MME in the GA group versus 27.5 MME in the SA group (P = 0.14). Antiemetics were administered less often as a prophylactic in the SA group (32%) versus 86% in the GA group (P < 0.001). CONCLUSIONS: SA reduces perioperative polypharmacy in patients ≥65 years undergoing TLIF procedures. Further research is necessary to determine if this reduction correlates to a decrease the incidence of postoperative cognitive dysfunction and delirium.

Spinal anesthesia in elective lumbar spinal surgery.

Spinal anesthesia (SA) is gaining recognition as a safe and efficacious regional alternative to general anesthesia for elective lumbar surgery. However, unfamiliarity with management issues related to its use has limited the adoption of awake spine surgery, despite its benefits. Few centers in the United States routinely offer SA for elective lumbar surgery, and a comprehensive workflow to standardize SA for lumbar surgery is lacking. In this article, we examine recent literature on the use of SA in lumbar surgery, review the experience of our institution with SA in lumbar surgery, and provide a cohesive outline to streamline the implementation of SA from the perspective of the anesthesiologist. We review the critical features of SA in contemporary lumbar surgery, including selection of patients, methods of SA, intraoperative sedation, and management of several important technical considerations. We aimed to flatten the learning curve to improve the availability and accessibility of the technique for eligible patients.

Assessing the Safety and Efficacy of Spinal Anesthesia in Patients with Significant Comorbidities.

BACKGROUND: Spinal anesthesia is an effective modality for lumbar surgery. Patient eligibility with respect to medical comorbidities remains a topic of debate. Obesity (body mass index ≥30 kg/m2), anxiety, obstructive sleep apnea, reoperation at the same level, and multilevel operations have variously been reported as relative contraindications. We hypothesize that patients undergoing common lumbar surgeries with these comorbidities do not experience greater rates of complications compared with controls. METHODS: We analyzed a prospectively collected database of patients undergoing thoracolumbar surgery under spinal anesthesia and identified 422 cases. Surgeries were less than 3 hours (the duration of action of intrathecal bupivacaine) and include microdiscectomies, laminectomies, and both single-level and multilevel fusions. Procedures were performed by a single surgeon at a single academic center. In overlapping groups, 149 patients had a body mass index ≥30 kg/m2, 95 had diagnosed anxiety, 79 underwent multilevel surgery, 98 had obstructive sleep apnea, and 65 had a previous operation at the same level. The control group included 132 patients who did not have these risk factors. Differences in important perioperative outcomes were assessed. RESULTS: There were no statistically significant differences in intraoperative and postoperative complications except 2 cases of pneumonia in the anxiety group and 1 case in the reoperative group. There were also no significant differences for patients with multiple risk factors. Rates of spinal fusion were similar among groups, although mean length of stay and operative time were different. CONCLUSIONS: Spinal anesthesia is a safe option for patients with significant comorbidities and can be considered for most patients undergoing routine lumbar surgeries.

Periprocedural Polypharmacy in Lumbar Fusions Performed Under Spinal Anesthesia Compared With General Anesthesia.

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.

A Second Prone Dose Algorithm for Patients Undergoing Spinal Anesthesia During Thoracolumbar Surgeries.

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.

Assessing the impact of spinal versus general anesthesia on postoperative urinary retention in elective spinal surgery patients.

OBJECTIVE: Postoperative urinary retention (POUR) is a common and vexing complication in elective spine surgery. Efficacious prevention strategies are still lacking, and existing studies focus primarily on identifying risk factors. Spinal anesthesia has become an attractive alternative to general anesthesia in elective lumbar surgery, with the potential of having a differential impact on POUR. METHODS: 422 spinal anesthesia procedures were prospectively collected between 2017 and 2021 and compared to 416 general anesthesia procedures retrospectively collected between 2014 and 2017, at a single academic center by the same senior neurosurgeon. The main outcome was POUR, defined as the need for straight bladder catheterization or indwelling bladder catheter placement after surgery due to failure to void. A power calculation was performed prior to data collection. RESULTS: The general anesthesia group had a higher rate of POUR (9.1 %) compared with the spinal anesthesia group (4.3 %), p = 0.005. At baseline, the spinal anesthesia cohort had an older average age and fewer patients with a history of previous spine surgery. Other comorbid conditions were comparable between the groups. For perioperative characteristics, spinal anesthesia patients had higher ASA scores, shorter operative times, shorter lengths of hospital stay, less operative levels, and zero use of intraoperative bladder catheterization. Acute pain service consult was similar between the groups. A multivariable logistic regression revealed that spinal anesthesia was associated with a significantly lower rate of urinary retention in the spinal anesthesia group (p = 0.0130), after adjusting for potentially confounding factors. Other statistically significant risk factors for POUR included diabetes, (p = 0.003), BPH (p = 0.014), operative time (p = 4.94e-06), and ASA score (p = 0.005). CONCLUSIONS: We collect and analyze one of the largest available cohorts of patients undergoing simple and complex surgeries under spinal and general anesthesia, finding that spinal anesthesia is independently associated with a lower incidence of POUR compared to general anesthesia, even when adjusted for potentially confounding risk factors. Further prospective trials are needed to explore this finding.

Use of Spinal Anesthesia in Lower Thoracic Spine Surgery: A Case Series.

BACKGROUND: Spinal anesthesia is a safe and effective alternative to general anesthesia for patients undergoing lumbar spine surgery, and numerous reports have demonstrated its advantages. To the best of our knowledge, no group has specifically reported on the use of spinal anesthesia in thoracic-level spine surgeries because there is a hypothetical risk of injuring the conus medullaris at these levels. With the advantages of spinal anesthesia and the desire for many elderly patients to avoid general anesthesia, our group has uniquely explored the use of this modality on select patients with thoracic pathology requiring surgical intervention. OBJECTIVE: To investigate the feasibility of performing thoracic-level spinal surgeries under spinal anesthesia and report our experience with 3 patients. METHODS: A retrospective chart review of medical records was undertaken, involving clinical notes, operative notes, and anesthesia records. RESULTS: Three spinal stenosis patients underwent thoracic laminectomy under spinal anesthesia. Two surgeries were performed at the T11-T12 level and 1 at the T12-L1 level. The average age was 82 years, average American Society of Anesthesiologists score was 3.3, and 1 identified as female. Two cases used hyperbaric 0.75% bupivacaine dissolved in dextrose, and 1 used isobaric 0.5% bupivacaine dissolved in water. CONCLUSION: Spinal anesthesia is feasible for thoracic-level spine procedures, even in elderly patients with comorbidities. We describe our cases and technique for safely achieving a thoracic level of analgesia, as well as discuss recommendations, adverse events, and considerations for the use of spinal anesthesia during lower thoracic-level spine operations.

Safety and feasibility of spinal anesthesia during simple and complex lumbar spine surgery in the extreme elderly (≥80 years of age).

OBJECTIVE: The extreme elderly population (≥80 years of age) is expected to triple globally by 2050 and surgeries in this age group are likely to increase. Spinal anesthesia has emerged as a safe and effective alternative to general anesthesia in lumbar surgery and may particularly benefit extreme elderly patients concerned with post-operative cognitive dysfunction, poor physiological reserves, and polypharmacy. However, literature supporting its use in this population is lacking and there are potential challenges such as degenerative anatomy and medical comorbidities. Here, we assess the safety and feasibility of using spinal anesthesia in the extreme elderly. METHODS: Between 2017 and 2021, 424 consecutive lower thoracic and lumbar spine surgeries were performed under spinal anesthesia by a single surgeon at a large academic hospital and procedural details were collected in a prospective database. Forty-six patients were ≥ 80 years in age. Demographic, surgical, perioperative, and anesthetic data were retrospectively analyzed. RESULTS: The extreme elderly cohort had increased ASA scores, levels of surgery, and length of stay. Similar rates occurred for spinal headache, deep vein thrombosis, pneumonia, urinary tract infection, urinary retention, readmission within 30 days, acute pain service consult, return to the operating room, and durotomy. Intraoperative visualization of the spinal anesthesia dural puncture was increased in the extreme elderly (3 vs. 1 patient). CONCLUSION: We report one of the largest series of extreme elderly patients undergoing spinal anesthesia for simple and complex lumbar spine surgeries and demonstrate that spinal anesthesia can be safe and feasible in this population.

Dataset for carbon footprints of transforaminal lumbar interbody fusions performed under spinal or general anesthesia.

The datasets presented here quantify and compare the relative carbon footprints emitted by general versus spinal anesthesia in patients undergoing single-level transforaminal lumbar interbody fusions (TLIFs). Data were retrospectively collected from electronic medical records of 100 consecutive patients who underwent a single-level TLIF from a single neurosurgeon at a U.S. academic center. 50 patients were under general anesthesia, and another 50 patients were under spinal anesthesia. Clinic and operative notes were used to extract demographic and surgical information, whereas anesthesia records were used to extract anesthetic information. Using the anesthetic information, carbon dioxide equivalents (CO2e) were calculated for each type of anesthetic and summed together to compute the total carbon footprint for each patient. Our article entitled "Assessing the environmental carbon footprint of spinal versus general anesthesia in single-level transforaminal lumbar interbody fusions" is based on this data [1]. Raw datasets of the primary data collection as well as cleaned and analyzed datasets are presented. These datasets highlight the first known environmental impact calculation from medical records of a spine procedure, serving as a model for other interested investigators to explore and emulate. This data brief may help to pave the way towards future environmental research and practice changes within neurosurgical and orthopedic literature, an issue critical to the sustainability of our modern society.

Assessing the Environmental Carbon Footprint of Spinal versus General Anesthesia in Single-Level Transforaminal Lumbar Interbody Fusions.

BACKGROUND: The U.S. health care sector produces approximately 10% of national greenhouse gas emissions, paradoxically harming human health. Neurosurgery is a resource-intensive specialty that likely contributes significantly, yet literature assessing this impact is absent. We investigate the difference in carbon emissions between spinal versus general anesthesia in lumbar spine surgery. METHODS: A total of 100 patients underwent a single-level transforaminal lumbar interbody fusion (TLIF) from a single surgeon; 50 received spinal anesthesia and 50 received general anesthesia. Data were extracted from patient records. Amounts of anesthetics were calculated from intraoperative records and converted to carbon dioxide equivalents (CO2e). RESULTS: The median CO2e for general anesthesia was 4725 g versus 70 g for spinal anesthesia (P = 7.07e-18). The mean CO2e for general anesthesia was 22,707 g versus 63 g for spinal anesthesia. Desflurane use led to outsized carbon emissions. Carbon footprint comparisons are made with familiar units such as miles driven by a car, and are provided for a single TLIF, 50 TLIFs (single surgeon's cases in a year), and 488,000 TLIFs (annual spinal fusions in the United States). CONCLUSION: This is one of the first known comparative carbon footprint studies performed in neurosurgical literature. We highlight the dramatic carbon footprint reduction associated with using spinal anesthesia and reflect a single neurosurgeon's change in practice from using only general anesthesia to incorporating the use of spinal anesthesia. Within general anesthesia patients, desflurane use was particularly harmful to the environment. We hope that our study will pave the way toward future research aimed at uncovering and reducing neurosurgery's environmental impact.

Spinal anesthesia in contemporary and complex lumbar spine surgery: experience with 343 cases.

OBJECTIVE: Spinal anesthesia (SA) is an alternative to general anesthesia (GA) for lumbar spine surgery, including complex instrumented fusion, although there are relatively few outcome data available. The authors discuss their experience using SA in a modern complex lumbar spine surgery practice to describe its utility and implementation. METHODS: Data from patients receiving SA for lumbar spine surgery by one surgeon from March 2017 to December 2020 were collected via a retrospective chart review. Cases were divided into nonfusion and fusion procedure categories and analyzed for demographics and baseline medical status; pre-, intra-, and postoperative events; hospital course, including Acute Pain Service (APS) consults; and follow-up visit outcome data. RESULTS: A total of 345 consecutive lumbar spine procedures were found, with 343 records complete for analysis, including 181 fusion and 162 nonfusion procedures and spinal levels from T11 through S1. The fusion group was significantly older (mean age 65.9 ± 12.4 vs 59.5 ± 15.4 years, p < 0.001) and had a significantly higher proportion of patients with American Society of Anesthesiologists (ASA) Physical Status Classification class III (p = 0.009) than the nonfusion group. There were no intraoperative conversions to GA, with infrequent need for a second dose of SA preoperatively (2.9%, 10/343) and rare preoperative conversion to GA (0.6%, 2/343) across fusion and nonfusion groups. Rates of complications during hospitalization were comparable to those seen in the literature. The APS was consulted for 2.9% (10/343) of procedures. An algorithm for the integration of SA into a lumbar spine surgery practice, from surgical and anesthetic perspectives, is also offered. CONCLUSIONS: SA is a viable, safe, and effective option for lumbar spine surgery across a wide range of age and health statuses, particularly in older patients and those who want to avoid GA. The authors' protocol, based in part on the largest set of data currently available describing complex instrumented fusion surgeries of the lumbar spine completed under SA, presents guidance and best practices to integrate SA into contemporary lumbar spine practices.

The Role of Liposomal Bupivacaine in Reduction of Postoperative Pain After Transforaminal Lumbar Interbody Fusion: A Clinical Study.

BACKGROUND: Postoperative pain after transforaminal lumbar interbody fusion (TLIF) is a barrier to early mobility. Intraoperative local infiltration of anesthetic agents is standard practice to alleviate postoperative pain. Liposomal formulations may prolong the action of these anesthetic agents. The purpose of this study was to investigate the role of liposomal bupivacaine in postoperative pain control in patients undergoing unilateral, single-level TLIF. METHODS: From a cohort of 74 patients, half received nonliposomal local anesthetic and half received liposomal bupivacaine (LB) (LB group) via local infiltration. Both groups received a standard postoperative analgesia regimen. Demographic information, postoperative pain scores (visual analog scale), analgesic consumption, length of stay, and complications were retrospectively collected. RESULTS: The area under the curve of cumulative pain scores was significantly lower in the LB group between 0 and 12 hours (15.0 ± 15.6 vs. 45.6 ± 21.1, P = 0.003) and between 12 and 24 hours (37.6 ± 20.6 vs. 48.4 ± 24.9, P = 0.05) after surgery. Significantly fewer narcotic equivalents were consumed in the LB group between 12 and 24 hours (16.0 ± 13.4 mg vs. 24.1 ± 19.7 mg intravenous morphine equivalents, P = 0.04). Length of stay was significantly shorter in the LB group than in the control group (3.1 ± 0.9 days vs. 4.3 ± 1.3 days, P < .001). CONCLUSIONS: LB may be a useful adjunct during unilateral TLIF for decreasing pain and narcotic consumption in the first 24 hours after surgery and may also decrease overall length of stay.