The Spine Journal 6 (2006) 561–564
Lumbar microdiscectomy under epidural anesthesia: a comparison study Elias C. Papadopoulos, MDa, Federico P. Girardi, MDb, Andrew Sama, MDb, Ioannis P. Pappou, MDa, Michael K. Urban, MD, PhDc, Frank P. Cammisa, Jr., MD, FACSb,* a Spine Surgery, Spine Service, Hospital for Special Surgery, New York, NY 10021, USA Orthopedic Department, Spine Service, Hospital for Special Surgery, New York, NY 10021, USA c Anesthesia Department, Hospital for Special Surgery, New York, NY 10021, USA
b
Received 26 March 2005; accepted 10 December 2005
Abstract
BACKGROUND CONTEXT: Lumbar microdiscectomy is most commonly performed under general anesthesia, which can be associated with several perioperative morbidities including nausea, vomiting, atelectasis, pulmonary aspiration, and prolonged post-anesthesia recovery. It is possible that fewer complications may occur if the procedure is performed under epidural anesthesia. PURPOSE: To investigate the safety and efficacy of epidural anesthesia in elective lumbar microdiscectomies. STUDY DESIGN: A prospective study evaluating the relative morbidities associated with epidural anesthesia and general anesthesia for lumbar microdiscectomy. PATIENT SAMPLE: Forty-three patients scheduled for primary lumbar microdiscectomy. Two cohorts were formed and were studied separately; one observational of all the 43 patients, and a second cohort of 17 patients who agreed to enter in the randomized trial. OUTCOME MEASURES: The clinical outcome was determined by the presence of postoperative pain, the absence of anesthesia-related complications, and the overall postoperative recovery. METHODS: This was a prospective study. With institutional review board approval, 43 consecutive patients were enrolled in the study. However, only 17 patients agreed to be randomized to receive either general or epidural anesthesia for the procedure; the remaining 26 patients selected the type of anesthesia of their preference. Recorded data for all patients included: age; total surgical time; occurrence of nausea, vomiting, atelectasis, or cardiopulmonary complication; ability to arise out of bed on the day of surgery; and the total number of inpatient hospital days. Postoperative pain and satisfaction were assessed only in the randomized cohort. RESULTS: There were a total of 43 patients, with a mean age of 38.1 years. The patients undergoing epidural anesthesia were marginally older than those undergoing general anesthesia. The epidural and general anesthetic groups were not different with respect to surgical time, pain assessed with a linear visual analogue scale, hospital stay, or the likelihood of arising out of bed on the day of surgery. There were no major cardiopulmonary complications in either group. Patients with epidural anesthesia had significantly less nausea and vomiting. CONCLUSIONS: Epidural anesthesia as an alternative to general anesthesia has shown less postoperative nausea and vomiting in lumbar microdiscectomy. Nevertheless, given the small number of patients, this study should be considered as preliminary, showing small differences in minor potential complications. Ó 2006 Elsevier Inc. All rights reserved.
Keywords:
Epidural anesthesia; Lumbar spine; Microdiscectomy; Perioperative complications
Introduction FDA device/drug status: not applicable. Nothing of value received from a commercial entity related to this manuscript. * Corresponding author. Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. Tel.: (212) 606-1594; fax: (212) 774-2701. E-mail address:
[email protected] (F.P. Cammisa Jr) 1529-9430/06/$ – see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.spinee.2005.12.002
There are a variety of anesthetic options available for use during spine surgery, broadly classified as general, regional (including epidural and spinal), and local anesthesia. Advances and refinements in techniques, anesthetic agents, and delivery systems over the last few decades have
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allowed for less empirical and more controlled anesthesia. The choice of technique depends on patient characteristics, the particular spine procedure, the extent and duration of surgery, and the experience of the anesthetist. Advances in minimally invasive spine surgery have resulted in decreases in operative time, perioperative morbidity, postoperative recovery time, interval to onset of ambulation, and duration of hospital stay. Consequently, the need for use of anesthetic techniques matched for similar characteristics is highlighted. General anesthesia has traditionally been used for lumbar microdiscectomy and continues to be the most common choice for this procedure. Regional and local techniques are, however, quite commonplace and are being used more widely and frequently, with epidural anesthesia being safer than spinal with respect to cardiac or neurological complications [1–4]. The potential advantages of epidural anesthesia in spine surgery include avoidance of airway manipulation; self-positioning of the awake patient that lessens brachial plexus and face injury; decreased need for narcotics; preservation of protective reflexes; and decreased operative blood loss, postoperative recovery time, nausea, vomiting, stress responses, and thromboembolic phenomena [5–9]. Potential drawbacks and complications include inadvertent injection of the local anesthetic intravascularly or into the intradural (subarachnoid) space, neurological injury, urinary retention, slow onset, and inadequate duration of anesthesia [2,3,10]. This prospective, partially randomized study was designed to investigate the safety and efficacy of epidural anesthesia and compare it with general anesthesia in elective lumbar microdiscectomies.
Methods After approval by the institutional review board and written, informed consent, patients who were selected and scheduled for elective primary lumbar microdiscectomies were asked to participate. Inclusion criteria were single-level disc disease diagnosed by standard clinical and radiologic means, a primary complaint of sciatica, and satisfaction of indication criteria for disc excision. Exclusion criteria were contraindications to epidural anesthesia (eg, local infection, coagulopathy), contraindications to regional anesthesia in the prone position without a protected airway (morbid obesity, sleep apnea), or prior lumbar surgery at the same level. Essentially, patients with no contraindications to either anesthetic technique and thus eligible to be randomized were asked to participate. A total of 43 patients were enrolled over a 1-year period. Seventeen of these agreed to be randomly assigned to receive either epidural or general anesthesia. The remaining 26 patients selected the type of anesthesia they preferred, but consented to having their perioperative data used for
comparative purposes. Thus, two cohorts were formed and were studied separately; one observational of all the 43 patients, and a second cohort of 17 patients who had entered the randomized trial; in the first cohort, 27 discectomies were conducted under epidural anesthesia and 16 under general anesthesia. In the latter, 10 patients were operated under epidural anesthesia and 7 under general anesthesia. An anesthesiologist administered all anesthesias. Patients within each group were anesthetized in similar fashion. The 16 patients receiving general anesthesia were induced with propofol (2 mg/kg), fentanyl (5 mg/kg), and vecuronium 0.1 mg/kg. N2O/O2 (2:1), isoflurane (0.3%), and fentanyl 1.2 mg/kg/hour were used for maintenance of anesthesia. The 27 patients receiving epidural anesthesia were given a single injection of 20–30 cc of 2% lidocaine with epinephrine (1:200,000) and 100 mg of fentanyl at least two levels above the surgical site using a 17-gauge Tuohy needle. Sedatives included propofol (100–200 mg) and midazolam (5–10 mg). An epidural catheter was placed in the event that additional anesthesia was required before the end of the case. The senior surgeon of this study (FPC) performed all discectomies. Patients were positioned in the prone position on a Relton-Hall frame with their head turned to one side, and those anesthetized with epidural anesthesia were asked if they were ‘‘comfortable’’ before the induction of sedation. The patients underwent typical one-level microdiscectomy; no patient had a radical excision of the disc involving curettage of the disc space. In all patients, postoperative pain was controlled with oral analgesics; parenteral agents were given to those unable to tolerate oral agents. The postoperative rehabilitation protocol included walking within 24 hours after the operation, stretching exercises in 10 days, return to work in 3 to 6 weeks, and permission for sports in 4 to 6 months. Preoperative data collected included age, gender, and number of smokers. Intraoperatively, the volume and level of epidural agent, surgical time, anesthetic time (total time in the operating room including surgical time), and cardiopulmonary complications (eg, elevated blood pressure and aspiration) were documented. The number of patients who ambulated on the day of surgery, incidence of headaches, atelectasis, nausea, vomiting and other complications, and total hospital stay were included in the postoperative data compiled. Additionally, in the randomized cohort, patient satisfaction and 24-hour pain scores were recorded; patient satisfaction was determined by the patient indicating to a nurse whether the experience was ‘‘excellent,’’ ‘‘good,’’ ‘‘fair,’’ or ‘‘poor.’’ Chi-square statistical analysis was conducted. Statistical differences between the two groups’ satisfaction in the randomized cohort were sought using the Mann-Whitney test (ordinal data). The alpha level was set to 0.05. All statistical analysis was performed using InStat 3.05 (GraphPad Software Inc., San Diego, CA).
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Table 1 Demographic data (all patients)
Epidural anesthesia (n527) General anesthesia (n516)
Mean age (years)
Age range (years)
Gender
Weight (kg)
Height (cm)
Smokers
40.2 (9.8)
21–59
74.1 (15.3)
172.2 (10.2)
5
34.7 (7.7)
27–57
11 16 6 10
72.6 (11.0)
168.3 (8.2)
4
Results There were a total of 43 patients enrolled, with a mean age of 38.0 years and an age range from 21 to 59 years (Table 1). Patients of the epidural group were marginally older (mean age of 40.2 years vs. 34.7 years). There were a total of 26 males and 17 females. Nine of the 43 patients smoked. Weight and height were comparable between groups. One patient from each of the two groups had a preoperative diagnosis of hypertension, and one from the epidural group was asthmatic. Epidural injections were given at a single level between T12–L5, with the majority administered between L1–L2 (30.8%) and L3–L4 (50.0%) on the first attempt. The level selected was adequately remote from the operative site to avoid surgical interference. None of these cases had to be converted to general anesthesia, and there were no dural punctures. Differences between the groups in the observational cohort, with respect to surgical and anesthetic times, duration of hospital stay, and interval to ambulation were not statistically significant (Table 2). There were no major cardiopulmonary complications in either group. One patient from each group complained of headache while in the post-anesthesia care unit. The incidence of nausea and vomiting while in the post-anesthesia care unit was significantly higher in the general anesthetic group (Table 3). One patient had nausea in the epidural group (3.7%) versus four in the general anesthetic group (25.0%; p5.04). Three patients had vomiting, all from the general anesthetic group (18.8%; p5.02). The 17 patients who were randomized to either general anesthesia (n57) or epidural anesthesia (n510) were reevaluated 24 hours after the operation. Pain assessed with
Table 2 Mean times and intervals (all patients) Mean surgical time (min) Epidural 65.4 (15.2) anesthesia (n527 General 63.6 (26.6) anesthesia (n516) p value .80 pts5patients.
Mean anesthetic time (min)
Ambulation on day of surgery
103.9 (17.2)
10 pts (37.5%) 2.1
Hospital stay (days)
females males females males
a linear visual analogue scale (10 cm VAS) showed no differences between the two groups. Overall the patients who received general anesthesia showed a higher incidence of headache and nausea/vomiting (Table 4). This cohort also reported satisfaction after the operation; in the epidural group, 9 of 10 patients reported excellent experiences with the anesthetic choice and 1 patient good. In the general anesthetic group (7 patients), 4 patients reported excellent experiences, 2 good, and 1 fair. Nevertheless, these results were not statistically significant (p 5 .346). All 10 patients of the epidural group said they would choose the same anesthetic in the future, whereas 6 of 7 from the general anesthetic group would do so.
Discussion Traditionally, general anesthesia is used in herniated disc surgery; nevertheless, regional anesthesia, either spinal or epidural, has been a successful alternative in spinal surgery. In 1960, Matheson [6] reported lower blood losses during lumbar laminectomies with the use of epidural anesthesia. He reported the major drawbacks as being headaches, urinary retention, and a short duration of action. Greenbarg et al. [5], in a review of 80 patients undergoing lumbar spine surgery under either epidural or general anesthesia (in equal cohorts), showed a need for less parenteral narcotics, a trend towards decreased blood loss, and a lower incidence of urinary retention in the epidural group. Smrcka et al. [11] reported 40 years of experience on discectomy in lateral position with epidural anesthesia. They found epidural anesthesia safe and highly tolerable, stressing the advantage of verbal communication between the surgeon and the patient that enables intraoperative assessment of the adequacy of the decompression [11]. Demirel et al. [12] randomized 60 patients undergoing discectomy or laminectomy into two groups, which received either general or epidural anesthesia; the latter was superior to general in causing fewer episodes of hypertension and less blood loss [12]. The epidural anesthesia Table 3 Early complications in the post-anesthesia care unit (all patients, n543)
105.5 (27.7)
.84
3 pts (18.75%) 1.8
.22
.81
Epidural General p value
Headache (%)
Vomiting (%)
Nausea (%)
1 (3.7) 1 (6.3) .70
d 3 (18.8) .02
1 (3.7) 4 (25.0) .04
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Table 4 Symptoms 24 hours after surgery (randomized cohort, n517)
Epidural (n510) General (n57) p value
Mean 24-hour pain score (1–10)
Nausea/ Vomiting
24-hour headache
4 (1–8) 4 (2–6) 1.00
2 (20.0%) 5 (71.4) .03
2 (20.0%) 3 (42.9) .31
group also showed less postoperative pain and nausea [12]. The difference to the present study was the mixed laminectomy and microdiscectomy population. Nevertheless, they were able to randomize all of their patients, reporting significant difference with respect to postoperative nausea in the epidural anesthesia group. Spinal anesthesia has proven its superiority to general anesthesia in orthopedic procedures, showing less blood loss, thromboembolic complications, and short-term mortality [13]. Decreased blood loss during lumbar spine surgery has been observed with spinal [9] and epidural [8,12] anesthesia when compared with general anesthesia, mainly through sympathetic blockage induced vasodilatation and hypotension. Intraoperative hemodynamics showed less incidence of increased blood pressure [8,12]. In the present series, the absence of intraoperative complications and major cardiopulmonary complications may be expected by the inclusion of relatively low-risk patients. Risk factors for anesthesia such as advanced age, obesity, and medical disorders (eg, hypertension, diabetes, renal disease, ischemic heart disease, chronic obstructive pulmonary disease) were not common in this group of patients. The major advantages of regional anesthesia are the excellent postoperative analgesia along with reduced nausea and vomiting [9,12]. In this study and in all patients, vomiting and nausea were significantly less in the epidural anesthetic group shortly after surgery and after 24 hours. The occurrence of headaches was similar for both groups in the observational cohort while in PACU, but less in the epidural anesthetic group in a 24-hour period as that was observed in the randomized group. Headaches may occur postoperatively when the dura is perforated, but also may occur postoperatively after general anesthesia as a result of a lack of food, stimulants (coffee), or the effect of the anesthetics. Finally, in the randomized patient cohort, no difference in surgical site pain (visual analogue scale score) was identified between the two groups.
The limitations of this study are the small number of patients, which decreases the significance of the statistical analysis, and the inability to randomize all patients but 17, because the decision about the anesthesia type in the rest of the patients relied on their personal preference. Therefore, this study should be considered as preliminary, showing small differences in minor and common potential complications, such as nausea and vomiting. Conclusions about the overall efficacy and safety of the two anesthetic approaches could be drawn with safety in larger patient cohorts. References [1] Vandam L, Koide M, Pilon RN, Vandam LD, Lowell JD. Neurological sequelae of spinal and epidural anesthesia. Anesthetic experience with total hip replacement. Int Anesthesiol Clin 1986;24:231–55. [2] Scott DB, Hibbard BM. Serious non-fatal complications associated with extradural block in obstetric practice. Br J Anaesth 1990;64: 537–41. [3] Tanaka K, Watanabe R, Harada T, Dan K. Extensive application of epidural anesthesia and analgesia in a university hospital: incidence of complications related to technique. Reg Anesth 1993;18:34–8. [4] Auroy Y, Narchi P, Messiah A, Litt L, Rouvier B, Samii K. Serious complications related to regional anesthesia: results of a prospective survey in France. Anesthesiology 1997;87:479–86. [5] Greenbarg PE, Brown MD, Pallares VS, Tompkins JS, Mann NH. Epidural anesthesia for lumbar spine surgery. J Spinal Disord 1988;1:139–43. [6] Matheson D. Epidural anaesthesia for lumbar laminectomy and spinal fusion. Can Anaesth Soc J 1960;7:149–57. [7] Scoville WB. Epidural anesthesia and lateral position for lumbar disc operations. Surg Neurol 1977;7:163–4. [8] Kakiuchi M. Reduction of blood loss during spinal surgery by epidural blockade under normotensive general anesthesia. Spine 1997;22: 889–94. [9] 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. [10] Giebler RM, Scherer RU, Peters J. Incidence of neurologic complications related to thoracic epidural catheterization. Anesthesiology 1997;86:55–63. [11] Smrcka M, Baudysova O, Juran V, Vidlak M, Gal R, Smrcka V. Lumbar disc surgery in regional anaesthesiad40 years of experience. Acta Neurochir (Wien) 2001;143:377–81. [12] 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. [13] Covino BG. Rationale for spinal anesthesia. Int Anesthesiol Clin 1989;27:8–12.
