Regional anesthesia versus general anesthesia for surgery on the lumbar spine: A review of the modern literature

Clinical Neurology and Neurosurgery 119 (2014) 39–43

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Clinical Neurology and Neurosurgery journal homepage: www.elsevier.com/locate/clineuro

Review

Regional anesthesia versus general anesthesia for surgery on the lumbar spine: A review of the modern literature夽 Joaquin O. De Rojas, Peter Syre, William C. Welch ∗ Department of Neurosurgery, University of Pennsylvania, Philadelphia, USA

a r t i c l e

i n f o

Article history: Received 21 August 2013 Received in revised form 12 November 2013 Accepted 19 January 2014 Available online 27 January 2014 Keywords: Lumbar Laminectomy Discectomy Spinal anesthesia General anesthesia

a b s t r a c t Lumbar spine surgery can be performed using different anesthetic techniques such as general endotracheal anesthesia (GA) or spinal-based regional anesthesia (RA). Several studies have been performed comparing these two anesthetic techniques and have revealed disparate results. As such, we set out to review the relevant literature. We performed a literature search for clinical articles comparing cohorts of patients who underwent RA versus GA for lumbar spine surgeries. We compared results of these studies between groups with respect to the following outcome variables: heart rate (HR), mean arterial pressure (MAP), blood loss, duration of surgery, time spent in the PACU, post-operative analgesic use or pain scores, urinary retention rates, and nausea or anti-emetic requirements. Eleven studies were identified that compared cohorts of patients who underwent GA or RA. Of these, 4 were randomized control trials, 3 were case control trials, 2 were prospective cohorts, and 2 retrospective analyses. Seven-out-of-seven studies reported reduced HRs and MAPs in the RA compared to GA group, and 7/9 studies reported a lower incidence of post-operative analgesic requirement and/or decreased pain scores for the RA group. Our review of the literature suggests that both RA and GA are safe and effective techniques for lumbar spine surgery and that RA may prove a better alternative than GA for healthy patients undergoing simple lumbar decompression procedures or for patients who are at high risk for general anesthetic complications. Published by Elsevier B.V.

Contents 1. 2. 3.

4.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Literature review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Hemodynamic status (heart rate, mean arterial pressure, and blood loss; Table 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. Surgery time (Table 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. PACU time (Table 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5. Post-operative narcotic use and/or pain score (Table 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6. Post-operative urinary retention (Table 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.7. Post-operative nausea (Table 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1. Proposed mechanisms for favorable outcomes of RA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2. When to not use RA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

40 40 40 40 40 41 41 41 41 41 41 43 43

Abbreviations: GA, general endotracheal anesthesia; RA, regional anesthesia; post-op, post-operative; HR, heart rate; MAP, mean arterial pressure; PACU, post-operative anesthesia care unit; VAS, visual analogue scale. 夽 Portions of this work were presented in abstract form/in poster form/as proceedings at the Pennsylvania Neurosurgical Society 99th Annual Scientific Meeting, Hershey, PA, July 2012. ∗ Corresponding author at: Department of Neurosurgery, University of Pennsylvania, Department of Neurosurgery at Pennsylvania Hospital, Washington Square West Building, 235 South 8th Street, Philadelphia, PA 19106, USA. Tel.: +1 215 829 6700; fax: +1 215 829 7895. E-mail addresses: [email protected] (J.O. De Rojas), [email protected] (W.C. Welch). 0303-8467/$ – see front matter. Published by Elsevier B.V. http://dx.doi.org/10.1016/j.clineuro.2014.01.016

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5.

J.O. De Rojas et al. / Clinical Neurology and Neurosurgery 119 (2014) 39–43

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

43 43

1. Introduction

2. Methods

Lumbar and lower thoracic spinal surgery can be safely performed under a variety of anesthetic techniques. These include techniques such as general endotracheal anesthesia (GA) or a more “local” method paired with sedation that we will refer to as regional anesthesia (RA), and which includes epidural anesthesia via catheter infusion and spinal anesthesia via injection. The authors of a recent study comparing RA and GA approaches [1] proposed that the qualities of an excellent anesthetic technique should include the following features: rapid onset, ease of reversal of effects, maintenance of hemodynamic stability during operations without the need of blood transfusions, a decreased recovery room stay, as well as reduced post-op pain, nausea, vomiting, or additional anesthetic requirements. For lower trunk and limb surgical procedures, the literature notes various advantages of RA over GA, including reduced pulmonary complications [2], intraoperative blood loss [3], perioperative cardiac ischemic incidents, hypoxic episodes, arterial and venous thrombosis [4], and decreased incidence of postoperative cognitive dysfunction, all of which suggests advantages of RA over GA in certain orthopedic procedures. Most recently, a French prospective cohort study reported that elderly patients who received GA in the past decade were significantly more likely to develop dementia than age-matched controls (relative risk 1.35, 95% CI, 1.11–1.63), suggesting another advantage of using RA over GA [5]. These findings highlight the need to explore the advantages and disadvantages of RA techniques for common spine procedures such as laminectomy and discectomy. Proposed advantages of RA over GA for spine surgery include the ability to carry out prolonged operations in the prone position without airway compromise [6,7], while also avoiding brachial plexus injury and pressure necrosis of the face because of patient self-positioning. RA also has the potential to reduce length of inpatient stays and reduce overall hospital costs. Although spinal anesthesia is widely accepted for lower extremity surgeries and total join arthroplasties, GA is by far the most frequently used anesthetic technique for common spinal surgical procedures such as microdiscectomy or lumbar laminectomy. This may be due to greater acceptance by patients, the ability to easily extend the duration of an operation using GA, and/or anesthesiologist preference for GA because of a more secure airway establishment prior to patient placement in the prone position [8]. Nevertheless, some centers have been using regional anesthesia in lumbar spine surgery. For example, the authors of a Cleveland Clinic study state that spinal anesthesia has been routinely used at their institution for over two decades and for patients of all ages undergoing lumbar spine procedures [9–11]. Our neurosurgery group at the University of Pennsylvania, Pennsylvania Hospital, has also routinely used regional anesthesia for lumbar laminectomies and discectomies. Although several studies have been performed comparing outcomes of RA versus GA for lumbar spine surgery, there have not been recent reports summarizing results across studies. Our goal is to review the relevant literature to identify and compare intra and post-operative outcomes between regional and general anesthetic approaches.

Clinical studies in the English literature that described patients undergoing either general or regional anesthesia for simple, lumbar spine surgery were identified from electronic databases including PubMed, Medline and EMBASE; Index Medicus; bibliographies of pertinent articles; and expert consultation. Review of textbooks and the “Related Articles” feature of PubMed supplemented these searches. The search strategy included various medical subject headings (MeSH) terms: general anesthesia, regional anesthesia, spinal anesthesia, epidural anesthesia, lumbar spine, spine surgery, discectomy, microdiscectomy, and laminectomy. We eliminated all non-clinical articles, as well as those articles that did not feature simple, 1–3 level laminectomy, discectomy, or microdiscectomy as the surgical procedure, those that included hardware placement, or those that featured more complex surgical procedures. We chose to focus on those surgical procedures most commonly performed, namely lumbar discectomy, laminectomy, or microdiscectomy. The following outcome variables, compared between RA and GA groups across studies, were collected to constitute our analysis: mean heart rate (HR), mean arterial pressure (MAP), blood loss, duration of surgery, post-operative (post-op) anesthesia care unit (PACU) time, post-op narcotic use/pain scale, post-op urinary retention, and post-op nausea/anti-emetic use/vomiting. We chose to exclude the frequently featured outcome variables “surgeon satisfaction” and “patient satisfaction” because of lack of objectivity. 3. Results 3.1. Literature review Our search yielded a total of 31 articles. We excluded studies if they did not feature any of our designated outcome variables, had confounding factors in their experimental design, showed clear demographic discrepancies between groups, or had missing statistical data. One study containing results relevant to our analysis was excluded because it did not report adequate statistical data [12]. After applying the exclusory criteria, 12 studies remained. Two of the studies were noted to feature the same data and, as such, were counted as a single study [10,11]. This yielded a final N of 11. Of these studies, spinal anesthesia was used as the RA technique in 8 of 11 studies and epidural anesthesia was used in 3 of 11 studies. The method of GA did not vary significantly between studies. Table 1 demonstrates an overview of study types. Table 2 demonstrates individual study characteristics. 3.2. Hemodynamic status (heart rate, mean arterial pressure, and blood loss; Table 3) The hemodynamic status of patients was reported in all of the 11 reviewed studies in the form of one or more of the following Table 1 Overview of study types. Featured study types include randomized control trials (RCT), case–control, prospective cohort, and retrospective studies. Type of study

Number of studies reviewed (N = 11)

Randomized control trial (RCT) Case control trial Prospective cohort Retrospective cohort

4 3 2 2

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Table 2 Study characteristics, including study type, surgery performed, group sizes (N given for GA and RA groups), type of RA used (spinal or epidural). Study

Type

Surgery

N (GA, RA)

RA used

Attari et al., 2011 Demirel et al., 2003 Greenbarg et al., 1988 Jellish et al., 1996 McLain et al., 2004; McLain et al., 2005 Sadrolsadat et al., 2009 Tetzlaff et al., 1998 Rung et al., 1997 Chen et al., 2011 Papadopoulos et al., 2006 McLain et al., 2007

RCT RCT Case–control RCT Case–control RCT Retrospective Retrospective Prospective Prospective Case–control

Discectomy or laminectomy for amniotomy or spinal cord tumor Lumbar partial hemilaminectomy and discectomy Lumbar laminectomy or discectomy Single- or double-level laminectomy or disc surgery Laminectomy or laminotomy for spinal stenosis or herniated disc Laminectomy for herniated lumbar disc Discectomy or laminotomy for spinal stenosis Lumbar disc surgery Endoscopic interlaminar discectomy of L5-S1 Lumbar microdiscectomy Microdiscectomy for herniated lumbar disc

37, 35 30, 30 40, 40 61, 61 200, 200 50, 50 192, 611 7, 7 50, 73 16, 27 33, 43

Spinal Epidural Epidural Spinal Spinal Epidural Spinal Spinal Spinal Epidural Spinal

variables: blood loss, heart rate (HR), mean arterial pressure (MAP). Seven studies included blood loss data [1,8,13–17]. Of these, 4/7 studies reported no difference in blood loss between RA and GA groups or they reported differences that did not reach statistical significance [8,14,16,17], and 3/7 studies reported a favorable decrease in blood loss for the RA compared to GA group [1,13,15]. All 7/7 studies that featured HR and MAP variables, including 4 RCTs, reported a favorable hemodynamic outcome for the RA over GA group in the form of lower mean HR, lower MAP, or a smaller change in these outcomes across operative and immediate post-op time [1,8–11,13,15,17]. In one study, these results were deduced from decreased incidence of intraoperative tachycardia and postoperative hypertension in the RA compared to GA group [8]. Interestingly, one study did not report statistical testing data for these hemodynamic outcomes, but it was included in the analysis because it claimed statistical significance [9]. 3.3. Surgery time (Table 3) Anesthetic technique can affect the surgical procedure time, or surgery time, which is a subdivision of total anesthesia time. Nine total studies reported surgical time data, with 3 studies reporting statistically decreased times for the RA compared to GA group [10,11,13,15] and 6 studies showing no difference between groups [1,8,14,16,18,19]. 3.4. PACU time (Table 3) As with total surgery time, the reviewed studies varied with respect to PACU stay time between groups. A total of 7 studies reported PACU time data. Two-of-seven studies reported longer PACU times in the RA compared to GA group [9–11], 4/7 studies reported no difference between groups [1,8,15,16], and 1 study reported longer PACU stays for the GA compared to RA group [13]. Duration of hospital stay, although not chosen as an a priori outcome variable, deserves mention since it is related to PACU time and was reported in some studies. Two studies describe briefer hospital stays for the RA compared to GA group [10,11,18], and 4 studies showed no significant difference in hospital stay time between groups [1,14,16,19]. 3.5. Post-operative narcotic use and/or pain score (Table 3) The amount of post-op narcotic use, or the related variable “pain score”, whether in the PACU or when the patient first arrives on the floor, is reported in 9 of the studies. Seven-of-nine studies reported favorable post-op pain outcomes for the RA relative to GA group, with 4 of these studies reporting decreased incidence of narcotic use [1,8,15,16], one study reporting lower analgesic dose requirements [14], another study reporting lower morphine sulfate infusion rates [10,11], and another study reporting significantly lower pain scores for the RA group [13]. Two-out-of-nine studies

reported statistically similar pain scores [19] or analgesic infusion rates [9] between groups. 3.6. Post-operative urinary retention (Table 3) Anesthesia choice can affect the severity of post-op urinary retention, a variable featured in five of the featured studies. Threeof-five studies reported post-op urinary retention rates to be more common in patients undergoing GA [9–11,14]. Two-of-five studies described no such difference between groups [13,15]. 3.7. Post-operative nausea (Table 3) Post-operative nausea was the final factor that we compared between groups, and 8 of studies featured this data. Five-of-eight of the studies showed a higher incidence of nausea [10,11,13,15,19] or a higher incidence of anti-emetic use [16] in the GA compared to RA group, but 3/8 studies reported no significant difference in post-op nausea [1,8] or anti-emetic requirement [9] between groups. 4. Discussion RA and GA are both reasonable anesthetic approaches for lumbar spine surgery as there is no clearly superior technique in terms of morbidity or mortality [18]. However, many of the studies featured in this review suggest short-term, secondary benefits of RA over GA. McLain’s randomized and controlled case–control study of 400 patients [10,11] concluded that RA was at least as effective as GA for performing elective lumbar decompression surgeries and proposed some advantages of RA over GA, including improved patient perioperative hemodynamic profiles, decreased analgesic requirement, and decreased incidence of post-op nausea. Of the 4 randomized controlled trials (RCTs) analyzed, 3 of them reported similarly favorable hemodynamic status, blood loss, and post-op analgesic requirement outcomes for their RA groups [1,13,15]. The fourth RCT, Sadrolsadat et al.’s study [8], did not demonstrate as clear an advantage between groups with regard to these parameters, although the authors did report a decreased incidence of perioperative tachycardia, hypertension, and analgesic use in the RA compared to GA group. Of note, the authors mention that their use of propofol as a sedative in the RA but not GA group may have confounded these outcomes [8], but this confounder was not present in the other studies mentioned and is, as a result, is insufficient in explaining the favorable outcomes of RA. In summary, all studies that featured heart rate and blood pressure data (7/7) report favorable hemodynamic outcomes for the RA over GA group, including 4/4 RCTs. More than half of the studies that featured pain control outcome data (7/9), including 4/4 RCTs, report favorable outcomes for RA. Additionally, more than half of the studies that featured nausea/vomiting data (5/8), including 3/4 RCTs, suggested favorable outcomes for RA. For all other variables

HR or max HR

MAP or max MAP

Blood loss

Surgery time

PACU time

Analgesic use or pain score

Urinary retention

Nausea

Attari et al., 2011

GA: +17.5 ± 5.5 RA: −13.2 ± 3.9 P < 0.05 (HR)

GA: +21.0 ± 6.7 RA: −25.1 ± 4.2 P < 0.05 (MAP)

GA: 350 ± 35 RA: 210 ± 40 P < 0.05

GA: 111.0 ± 7.4 RA: 115.0 ± 3.2 P > 0.05

GA: 50 ± 5.9 RA: 55 ± 6.7 P > 0.05

GA: 16.2% RA: 0% P < 0.05 (incidence)

–

GA: 2.7% SA: 5.7% P > 0.05

Demirel et al., 2003

GA > RA across time P < 0.05

GA > RA across time P < 0.05

GA: 288.6 ± 112.5 RA: 180.4 ± 70.4 P < 0.05

GA: 137.6 ± 26.8 RA: 118.8 ± 35.4 P < 0.05

GA: 52.9 ± 10.2 RA: 34.4 ± 12 P < 0.05

GA: 3.5 ± 1.22 RA: 0.2 ± 0.5 P < 0.05 (pain score)

GA: 17% RA: 20% P > 0.05

GA: 53% RA: 10% P < 0.05

Greenbarg et al., 1988

–

–

GA: 290 RA: 188.3 P > 0.05

GA: 120.3 RA: 115.2 P > 0.10

–

GA: 3.2 RA: 1.1 P < 0.01 (doses)

GA: 50% RA: 10% P < 0.001

–

Jellish et al., 1996

GA > RA at PACU admission P < 0.05

GA > RA across time P < 0.05

GA: 221 (32) RA: 133 (13) P < 0.05

GA: 81.5 (3.6) RA: 67.1 (2.8) P < 0.05

GA: 80.3 (2.8) RA: 85.4 (4.2) P > 0.05

GA: 80.3% RA: 26.2% P < 0.05 (incidence)

GA: 22.9% RA: 14.8% P > 0.05

GA: 25% RA: 5% P < 0.05

McLain et al., 2004; McLain et al., 2005

GA: 79 RA: 72 P < 0.001

GA: 105 RA: 95 P < 0.001

–

GA: 120 RA: 105 P < 0.05

GA: 120 RA: 225 P < 0.001

GA: 1.0 RA: 0.6 P < 0.01 (doses/h)

GA: 24% RA: 8% P < 0.001

GA > RA P < 0.005

Sadrolsadat et al., 2009

GA: 26% RA: 6% P < 0.01 (tachycardia incidence)

GA: 38% RA: 6% P < 0.001 (hypertension incidence)

GA: 438 ± 67 RA: 465 ± 69 P > 0.05

GA: 94.1 ± 17.9 RA: 94.4 ± 17.3 P > 0.05

GA: 23.8 ± 7.8 RA: 21.7 ± 8.8 P > 0.05

GA: 62% RA: 22% P < 0.001 (incidence)

–

GA: 18% RA: 10% P > 0.05

Tetzlaff et al., 1998

GA: +21.2 (11.6) RA: −26.1 (4.0) P < 0.05 (HR)

GA: +18.9 (5.6) RA: −14.2 (4.0) P < 0.05 (MAP)

GA = RA P > 0.05

–

–

–

–

–

Rung et al., 1997

–

–

GA: 63 ± 52 RA: 45 ± 33 P > 0.1

GA: 99 ± 57 RA: 96 ± 28 P > 0.1

GA: 87 ± 29 RA: 48 ± 38 P > 0.1

GA: 71% RA: 0% P < 0.05 (incidence)

–

GA: 57% RA: 0% P < 0.05 (incidence of anti-emetic use)

Chen et al., 2011

–

–

–

GA: 74.8 ± 17.7 RA: 67.1 ± 33.9 P > 0.1

–

–

–

–

Papadopoulos et al., 2006

–

–

–

GA: 63.6 (26.6) RA: 65.4 (15.2) P > 0.5

–

GA: 4 RA: 4 P > 0.5 (pain score)

–

GA: 71% RA: 20% P < 0.05

McLain et al., 2007

GA > RA MSD

GA > RA MSD

–

–

GA: 144 RA: 234 P < 0.001

GA: 2.0 RA: 1.1 P > 0.5 (dose/h)

GA: 21.2% RA: 4.7% P < 0.05

GA: 6.1% RA: 2.3% P > 0.5 (incidence of anti-emetic use)

Summary

7/7 GA > RA

7/7 GA > RA

3/7 GA > RA 4/7 GA = RA

3/9 GA > RA 6/9 GA = RA

1/7 GA > RA 4/7 GA = RA 2/7 RA > GA

7/9 GA > RA 2/9 GA = RA

3/5 GA > RA 2/5 GA = RA

5/8 GA > RA 3/8 GA = RA

–, results not recorded or reported; MSD, missing statistical data and P values; RA, regional anesthesia; GA, general anesthesia.

J.O. De Rojas et al. / Clinical Neurology and Neurosurgery 119 (2014) 39–43

Study

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Table 3 Comparison of regional anesthesia to general anesthesia for lumbar spine surgery. Outcome variables include mean heart rate (HR) or maximum change in HR (max HR), mean arterial pressure (MAP) or maximum change in MAP (MAP), intraoperative blood loss (in mL), surgery time (in min), PACU time (in min), post-op analgesic use (in % incidence or doses administered) or pain score (as reported in primary study), post-op urinary retention (in % incidence), and post-op nausea (in % incidence or anti-emetic administration incidence). Outcomes variables, SDs (±value), SEMs (value) and P values are written as reported in primary studies.

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across studies, we believe that there were no clear advantages of one approach over another.

sample cases will be needed to validate our results and shed light on some of the proposed theoretical claims.

4.1. Proposed mechanisms for favorable outcomes of RA

References

Improved hemodynamic stability of RA over GA, as suggested by our review, is a possible result of inhibited release of stress hormones intraoperatively, leading to less elevations and fluctuations of MAP and HR [1,20–26]. Similarly, some researchers believe that RA leads to decreased blood loss because of vasodilation and hypotension caused by RA’s sympathetic blockade, as well as by the maintenance of spontaneous ventilation possible with RA, which leads to lower intrathoracic pressure and, as a result, less distension of epidural veins [27]. Reduced bleeding in patients receiving RA, although only reported in 3/7 studies, could be due to decreased episodes of intraoperative hypertension as compared to the GA groups [15]. More than half of studies demonstrated decreased post-op pain scores and/or narcotic requirement for the RA compared to GA group. The authors of one study highlights the existence of a residual sensory blockade after RA that is supported by the observation that sensory recovery lags behind motor recovery in this group but not in the GA group [1]. Finally, decreased pain scores in the RA group may be due to regional anesthesia’s more selective inhibition of afferent nociceptive sensitization pathways [1,28]. A little over half of studies also demonstrated decreased nausea and anti-emetic use in the RA compared to GA group. To explain this difference, it has been speculated that GA may inhibit gastric emptying leading to increased nausea and vomiting, while this phenomenon may be virtually absent with spinal or epidural anesthesia use [9,23]. The increased incidence of nausea and vomiting could also be due to N2 O gas use which was combined in the GA approach in some studies [29].

[1] Attari MA, Mirhosseini SA, Honarmand A, Safavi MR. Spinal anesthesia versus general anesthesia for elective lumbar spine surgery: a randomized clinical trial. J Res Med Sci 2011;16:524–9. [2] Scott NB, Kehlet H. Regional anaesthesia and surgical morbidity. Br J Surg 1988;75:299–304. [3] Modig J, Karlstrom G. Intra- and post-operative blood loss and haemodynamics in total hip replacement when performed under lumbar epidural versus general anaesthesia. Eur J Anaesthesiol 1987;4:345–55. [4] Rodgers A, Walker N, Schug S, McKee A, Kehlet H, van Zundert A, Sage D, Futter M, Saville G, Clark T, MacMahon S. Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomised trials. Br Med J (Clin Res Ed) 2000;321:1493. [5] Sztark F. Exposure to general anaesthesia could increase the risk of dementia in elderly. Euroanaesthesia 2013;18A:P11–4. [6] Cucchiara RF, Michenfelder JD. Vertebral column and spinal cord surgery. In: Clinical neuroanesthesia. London: Churchill Livingstone; 1990. p. 325–50. [7] Abrishamkar S, Aminmansour B, Arti H. The effectiveness of computed tomography scans versus magnetic resonance imaging for decision making in patients with low back pain and radicular leg pain. J Res Med Sci 2006:11. [8] Sadrolsadat SH, Mahdavi AR, Moharari RS, Khajavi MR, Khashayar P, Najafi A, Amirjamshidi A. A prospective randomized trial comparing the technique of spinal and general anesthesia for lumbar disk surgery: a study of 100 cases. Surg Neurol 2009;71:60–5. [9] McLain RF, Tetzlaff JE, Bell GR, Uwe-Lewandrowski K, Yoon HJ, Rana M. Microdiscectomy: spinal anesthesia offers optimal results in general patient population. J Surg Orthop Adv 2007;16:5–11. [10] McLain RF, Bell GR, Kalfas I, Tetzlaff JE, Yoon HJ. Complications associated with lumbar laminectomy: a comparison of spinal versus general anesthesia. Spine 2004;29:2542–7. [11] McLain RF, Kalfas I, Bell GR, Tetzlaff JE, Yoon HJ, Rana M. Comparison of spinal and general anesthesia in lumbar laminectomy surgery: a case-controlled analysis of 400 patients. J Neurosurg: Spine 2005;2:17–22. [12] Nicassio N, Bobicchio P, Umari M, Tacconi L. Lumbar microdiscectomy under epidural anaesthesia with the patient in the sitting position: a prospective study. J Clin Neurosci 2010;17:1537–40. [13] Demirel CB, Kalayci M, Ozkocak I, Altunkaya H, Ozer Y, Acikgoz B. A prospective randomized study comparing perioperative outcome variables after epidural or general anesthesia for lumbar disc surgery. J Neurosurg Anesthesiol 2003;15:185–92. [14] Greenbarg PE, Brown MD, Pallares VS, Tompkins JS, Mann NH. Epidural anesthesia for lumbar spine surgery. J Spinal Disord 1988;1:139–43. [15] Jellish WS, Thalji Z, Stevenson K, Shea J. A prospective randomized study comparing short- and intermediate-term perioperative outcome variables after spinal or general anesthesia for lumbar disk and laminectomy surgery. Anesth Analg 1996;83:559–64. [16] Rung GW, Williams D, Gelb DE, Grubb M. Isobaric spinal anesthesia for lumbar disk surgery. Anesth Analg 1997;84:1165–6. [17] Tetzlaff JE, Dilger JA, Kodsy M, Al-Bataineh J, Yoon HJ, Bell GR. Spinal anesthesia for elective lumbar spine surgery. J Clin Anesth 1998;10:666–9. [18] Chen HT, Tsai CH, Chao SC, Kao TH, Chen YJ, Hsu HC, Shen CC, Tsou HK. Endoscopic discectomy of L5-S1 disc herniation via an interlaminar approach: prospective controlled study under local and general anesthesia. Surg Neurol Int 2011;2:93. [19] Papadopoulos EC, Girardi FP, Sama A, Pappou IP, Urban MK, Cammisa Jr FP. Spine J 2006;6:561–4. [20] Davis FM, Laurenson VG, Lewis J, Wells JE, Gillespie WJ. Metabolic response to total hip arthroplasty under hypobaric subarachnoid or general anaesthesia. Br J Anaesth 1987;59:725–9. [21] Pflug AE, Halter JB. Effect of spinal anesthesia on adrenergic tone and the neuroendocrine responses to surgical stress in humans. Anesthesiology 1981;55:120–6. [22] Pflug AE, Aasheim GM, Foster C. Sequence of return of neurological function and criteria for safe ambulation following subarachnoid block (spinal anaesthetic). Can J Anaesth Soc 1978;25:133–9. [23] Nimmo WS, Littlewood DG, Scott DB, Prescott LF. Gastric emptying following hysterectomy with extradural analgesia. Br J Anaesth 1978;50:559–61. [24] Hebl JR, Horlocker TT, Kopp SL, Schroeder DR. Neuraxial blockade in patients with preexisting spinal stenosis, lumbar disk disease, or prior spine surgery: efficacy and neurologic complications. Anesth Analg 2010;111: 1511–9. [25] Basaranoglu G, Erkalp K, Saidoglu L, Aydas D, Ozdemir H, Teker M. Selective spinal anesthesia for limb amputation above knee level. J Clin Anesth 2011;23:169 [author reply 169]. [26] Limongi JA, Lins RS. Cardiopulmonary arrest in spinal anesthesia. Rev Bras Anestesiol 2011;61:110–20. [27] Kehlet H. The stress response to surgery: release mechanisms and the modifying effect of pain relief. Acta Chir Scand Suppl 1989;550:22–8. [28] Covino BG. Rationale for spinal anesthesia. Int Anesthesiol Clin 1989;27:8–12. [29] Watcha MF. Postoperative nausea and emesis. Anesthesiol Clin North America 2002;20:709–22.

4.2. When to not use RA Despite the suggested advantages of RA over GA for simple, 1–2 level lumbar spine decompression surgeries, there are several absolute and relative contraindications to RA, many of which were used as patient exclusory criteria in the featured studies. These include but are not limited to: patient refusal, severe or multilevel spinal stenosis, history of seizures, history of intracranial hypertension, coagulopathy, infection at site of needle, hypovolemia, near complete-total myelographic block, or myelographic demonstration of arachnoiditis [1]. It is also important to note that anesthetic choice should ultimately be based on the patient’s, surgeon’s and anesthesiologist’s comfort with the technique. 5. Conclusion Both general and regional anesthesia are effective techniques for use in 1–2 level lumbar laminectomy or disc surgery. There is no evidence to suggest that morbidity, mortality, or long-term complication rates differ between these two approaches [18]. However, our analysis of secondary outcomes across studies suggests that RA can be a worthwhile, if not advantageous alternative to GA in healthy patients undergoing simple lumbar decompressive surgeries provided that no contraindications to RA exist. Because of its suggested favorable hemodynamic profile and decreased postop narcotic requirement, we believe that the RA approach should be considered in older patients who may not tolerate GA because of a decreased cardiopulmonary reserve. In addition, older adults may also benefit from RA by avoiding the increased risk of postoperative cognitive dysfunction and theoretical risk of dementia after GA exposure [5]. Future well-designed studies with more