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  • Available online at www.sciencedirect.com Surgical Neurology 71 (2009) 60 – 65 www.surgicalneurology-online.com Spine A prospective randomized trial comparing the technique of spinal and general anesthesia for lumbar disk surgery: a study of 100 cases Seyed Hossein Sadrolsadat, MD a , Ali Reza Mahdavi, MD a , Reza Shariat Moharari, MD a , Mohammad Reza Khajavi, MD a , Patricia Khashayar, MD b , Atabak Najafi, MD a , Abbas Amirjamshidi, MD, MPH a,⁎ a Sina Hospital, Medical Sciences/University of Tehran, Tehran, Iran b Research and Development Center, Sina Hospital, Medical Sciences/University of Tehran, Tehran, Iran Received 13 July 2008; accepted 5 August 2008 Abstract Background: General anesthesia and regional anesthesia have both been shown to be suitable techniques for patients undergoing lower thoracic and lumbar spine surgery; however, GA is the most frequently used method. The purpose of this study was to conduct an acceptable RCT to compare the intraoperative parameters and postoperative outcome after SA and GA in patients undergoing elective lumbar disk surgery. Methods: Patients undergoing laminectomy for herniated lumbar disk during the years 2005 and 2007 were enrolled. They were randomly selected to undergo GA and SA. The variables recorded during the operation were the patients' HR, MAP, amount of blood loss, and surgeons' satisfaction with the operating conditions. The severity of pain, nausea, vomiting, and length of stay in the hospital were recorded in the postoperative course. Results: The mean blood loss was less in the group undergoing GA; however, the difference was not statistically significant. The surgeon's satisfaction was reported to be higher in the GA group. No major intraoperative complication was reported in either series. During the recovery period, hypertension was reported to happen more frequently in the patients undergoing GA; and postoperative nausea and vomiting were more frequent among patients recovering from SA. Conclusion: Contrary to previous studies, the findings of the present study revealed that SA has no advantages over GA. Moreover, it was showed that GA can reduce the related risks and complications in several aspects. © 2009 Elsevier Inc. All rights reserved. Keywords: General anesthesia; Lumbar disk surgery; Spinal anesthesia; Visual analog scale 1. Introduction going lower thoracic and lumbar spine surgery, and the hypothesis is that “GA is of equal value with SA for General anesthesia and regional anesthesia have both lumbar disc surgery.” Although GA is the more frequently been shown to be suitable techniques for patients under- used method, this preference may be due to the greater acceptance by patients, the ability to perform longer Abbreviations: ASA, American Society of Anesthesiologists; CVE, operations [1,16], or the anesthesiologist feeling more compensatory volume expansion; GA, general anesthesia; HR, heart rate; comfortable seeing that the airway is secured before placing IV, intravenous; MAP, mean arterial pressure; NPO, nothing by mouth (nil the patient in the prone position [14]. On the contrary, some per os); PACU, postanesthesia care unit; RCT, randomized controlled trial; anesthesiologists choose regional techniques because they SA, spinal anesthesia; TIVA, total intravenous anesthesia; TNG, trinitrogly- cerin; TOF, train-of-4 ratio; VAS, visual analog scale. believe it is accompanied with less blood loss [8] and less ⁎ Corresponding author. hemodynamic instability [6,18]. An additional advantage is E-mail address: abamirjamshidi@yahoo.com (A. Amirjamshidi). the patient's ability to reposition their extremities and chest 0090-3019/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2008.08.003
  • S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 61 to avoid nerve injury, brachial plexus palsy, or pressure The SA patients were placed in the seated position on necrosis to either the face or the chest wall [4,14]. Spinal arrival in the operating room. After the injection of local techniques may also reduce the incidence of pulmonary anesthetics (1 mL of lidocaine 1%), SA was delivered using complications compared with GA; however, episodes of a lumbar puncture at the L3-4 intervertebral disk space via urinary retention and infection were reported following this Quincke 25-gauge spinal needle and injection of 4 mL of method [13,19]. bupivacaine 0.5% in the subarachnoid space. There have been very few RCTs regarding this subject in Once the block was obtained, the patients were rolled the literature [3,7,11,12]. The purpose of this study was to into the supine position and allowed to rest until a stable conduct an acceptable RCT to compare the intraoperative maximal spread of the block to T6 through T10 was parameters and postoperative outcome after SA and GA in achieved. After about 10 minutes, the patient was turned patients undergoing elective lumbar disk surgery. to a prone position on the operating bed and placed on the standard laterally located chest roles in the semiflexed position. Oxygen was provided via face mask. During the 2. Material and methods operation, the patient was sedated with propofol infusion at 25 to 50 μg/(kg min) IV. At completion of the 2.1. Ethics and inclusion criteria operation, propofol was discontinued; and the patient was After approval of the study protocol by the Institutional rolled to supine position. The patients were then Ethical Board Committee, all the patients awaiting lami- transferred to the PACU. There were no dropouts in nectomy for herniated lumbar disk in 1 to 2 levels during the this series of patients. years 2005 and 2007 were enrolled in the study. 2.3. Data gathering Those with an ASA class higher than class III; patients Age, sex, height, and weight were the demographic with multilevel spinal stenosis, coagulopathy, localized characteristics entered for every patient. Electrocardio- infection (interpreted as a contraindication or a high risk graphic monitoring, noninvasive blood pressure, pulse for SA), or severe cardiac or liver disease; and cases with any oximeter, and capnography were recorded during the relative or absolute contraindication for SA [11] were operation in both groups. excluded from the study. The patient's HR (per minute) and MAP were recorded at An informed consent was obtained from all the patients several intervals: after enough description about the different methods being used for the patient during surgery. The patients were 1. The time at which the patient had entered the operation allocated into 2 groups based on computer-generated room, randomization. They were selected to undergo either GA 2. The time anesthesia was initiated, or SA. A single surgeon and a group of anesthesiologists 3. At the initiation of the operation (when incision was were responsible for performing all the operations. A performed), trained technician unaware of the objectives of the study 4. At the termination of the operation (placement of surgical and the method by which the patient was operated was dressing), responsible for gathering the required information. 5. Once anesthesia was terminated (when the patient was 2.2. Techniques transferred to the recovery room), and 6. When the patient was discharged from the recovery room. Patients undergoing GA were given 2 mg of IV midazolam. Induction was carried out using propofol IV Mean arterial pressure and HR were also assessed every (2 mg/kg) and fentanyl IV (2 μg/kg). Endotracheal 10 minutes for at least half an hour in the recovery room in intubation was facilitated with atracurium IV (0.5 mg/kg). both study groups (sample of the graphs taken for each Once the patients were intubated, they were placed in a prone patient in Figs. 1 and 2). position on a standard operating frame. Maintenance The amount of blood loss was assessed by measuring anesthesia consisted of oxygen 100% with propofol (100- the bloody gauzes' weight plus the volume calculated from 200 μg/[kg min]) and alfentanil (2 mL/400 mg propofol). the difference of suctioned fluid and the volume of Anesthetics were modified to maintain hemodynamic irrigation solutions administered (for the purpose of variables within 10% of the baseline values. Ten milligrams washing the operation site). The infused liquid during of atracurium was administered every 20 minutes as muscle anesthesia, accounting for those administered before relaxant. At the termination of GA, the anesthetic agents induction, was documented. were discontinued; and the patient breathed 100% oxygen. The severity of pain and nausea was evaluated using The patient was then rolled to a supine position on the 100-mm VAS; meperidine (25 mg IV) and metoclopramide postoperative bed. At that time, atropine and neostigmine were prescribed in cases with pain intensity more than were used to reverse the relaxation. When appropriate, they 50 mm and nausea more than 50 mm, respectively. Both were extubated and then transported to the PACU. drugs were readministered in intervals of 30 minutes, if
  • 62 S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 Table 1 The demographic and baseline data of the 2 groups enrolled in the study GA SA Age 45.2 ± 5.6 45.7 ± 5.2 Weight 75.2 ± 8.2 77.8 ± 7.5 Baseline MAP 92.6 ± 4.9 93.3 ± 6.2 Baseline HR 78.2 ± 6.4 78.6 ± 7.0 assessed to be hemodynamically stable and comfortable at the time of discharge. The total stay of the patients in PACU was also recorded. Hypotension or bradycardia was defined as the reduction of MAP or HR to less than 80% of the baseline amounts. Fig. 1. Sample of a graph showing the changes in MAP of a patient during Ephedrine IV 10 mg or more was administered in such cases. the study period. Numbers in the x-axis denote the time intervals at which MAP was assessed: 1, the time at which the patient had entered the operation On the other hand, hypertension or tachycardia was room; 2, the time anesthesia was initiated; 3, after the intubation; 4, at the considered when MAP or HR had raised to more than initiation of the operation (when incision was performed); 5, at the 120% of the baseline. These cases were treated using 20 to termination of the operation (placement of surgical dressing); 6, once 30 mg of propofol IV and/or TNG with an initial dose of anesthesia was terminated (when the patient was transferred to the recovery 10 μg/min. room); and 7, when the patient was discharged from the recovery room. During the pilot study, the difference between the hypotension rate in the 2 groups was calculated (15% vs required. The reinjection of the drugs every 4 hours was 40%); according to this findings and with α = .05 and a possible when the patient was transferred to the ward. power of 80%, a sample size of 100 (50 patients in each The number of blood bags injected during the operation, group) was required. the preoperative and postoperative values of hemoglobin, The data were analyzed using SPSS (Chicago, IL) version and the satisfaction rate of the surgeon were recorded. 11.5 software. The χ2 test and the Student t test were used Surgeon's satisfaction was evaluated using a 100-mm for comparing the variables between the 2 groups. P values VAS based on the satisfaction from the amount of blood in lower than .05 were considered as significant. the surgical field, patients' muscular relaxation, being motionless, and the possibility of assessing neurologic status immediately after the operation. The plausibility and 3. Results internal validity of the variants considered for VAS of the One hundred patients were enrolled in this study. The surgeon's satisfaction rate were examined in several mean age of the patients was 45.5 ± 5.4 years, and 50% were introductory sessions with the attending surgeons and male. There was no difference between the demographic data gained acceptable rates. and the baseline MAP and HR of the 2 groups (Table 1). Patients were discharged from the recovery room based The perioperational findings of both groups are outlined on Miller's Anesthesia 2005 guidelines, TOF ratio equal to in Table 2. Regarding the surgical and anesthesia durations, 0.85 in GA patients, and the regression of at least no statistically significant difference was observed between 4 dermatomes block in SA patients. All the patients were the 2 groups (P = .932 and .084, respectively). In comparison with the SA patients, the GA group lost about 26.5 ± 2.7 mL less blood during the operation, which was marginally significant (P = .054). Anyhow, no episodes of excessive hemorrhage or cases requiring blood transfusions occurred in Table 2 Intraoperative data for SA vs GA GA (n = 50) SA (n = 50) P Total anesthesia time (min) 126.4 ± 19.1 120.1 ± 16.9 .084 Operation time (min) 94.1 ± 17.9 94.4 ± 17.3 .932 Blood loss (mL) 438.0 ± 66.6 464.5 ± 69.3 .054 Hypotension 6 (12%) 24 (48%) b.001 Bradycardia 17 (34%) 17 (34%) 1.000 Tachycardia 13 (26%) 3 (6%) .006 Fig. 2. Sample of a graph showing the changes in HR of a patient during the IV fluid (mL) 2890.0 ± 290.8 2930.0 ± 378.1 .555 study period. Numbers in the x-axis denote the time intervals at which HR Surgeon's satisfaction 76.7 ± 7.5 64.0 ± 6.5 .038 was assessed (see Fig. 1 for interpretation of the numbers).
  • S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 63 Table 3 4. Discussion Postoperative data for SA vs GA GA SA P OR (95% CI) A good anesthetic technique should have both rapid onset and reversal of effects. It should provide desirable Hypertension 19 (38%) 3 (6%) b.001 9.6 (2.6-35.2) PACU time 23.8 ± 7.8 21.7 ± 8.8 .212 – intraoperative hemodynamic conditions and, if possible, Nausea and vomiting 3 (6%) 10 (20%) .037 3.9 (1.1-15.1) contribute to a reduced need for blood transfusion. More- in PACU over, it should permit the earliest possible discharge from the Nausea and vomiting 9 (18%) 5 (10%) .249 – PACU and minimize the common postoperative problems after 24 h such as pain, analgesics consumption, nausea, and vomiting Analgesic requirement 31 (62%) 11 (22%) b.001 5.7 (2.4-13.9) in PACU [5,17]. Analgesic requirement 37 (74%) 38 (76%) . 817 - The literature is largely supportive regarding SA used for after 24 h lumbar laminectomy, although not in an evidence-based OR indicates odds ratio; CI, confidence interval. manner; however, GA is the method of choice for spinal procedures according to some authors [7]. This concept either may be related to the lack of familiarity with the use of either group. Furthermore, just 12% of GA patients spinal techniques for anesthesia in such procedures or may compared with 24% of SA ones experienced hypotension reflect the uncertainty concerning the potential risks and during the operation (P b .001). complications incurred when spinal operations are carried Bradycardia was similarly seen in both groups, whereas out in a conscious patient under SA [20]. tachycardia was more frequent in those undergoing GA Several studies have compared SA and GA in lumbar (26% vs 6%, P = .006). It is noteworthy that, in 3 cases of the laminectomy surgery, and many of which have concluded SA group, coughing impeded the surgeons from proceeding SA as the preferred method [7,3,11,12]. However, the pre- for a while and that, in 1 case, hiccups made the condition sent study did not support this hypothesis. Table 4 outlines tense. However, no major intraoperative complication was the findings of the similar studies. reported in either of the series. On the whole, surgeon's In the present study, lower prevalence of nausea and satisfaction measured by VAS was higher in GA patients vomiting in the following day of the surgery, shorter (76.7 ± 7.5 mm) compared with SA patients (64.0 ± 6.5 mm), recovery time, and lower need for analgesics during the which was statistically significant (P = .038). recovery period were reported in patients undergoing SA. The postoperative findings are summarized in Table 3. The patients in the GA group were reported to experience Duration of recovery period was rather similar in the intraoperative hypotension as well as nausea and vomiting 2 groups (GA, 23.8 ± 7.8 minutes vs SA, 21.7 ± 8.8 minutes). (in the recovery room) less frequently than the other group. During the period, 19 of GA cases (38%) had hypertension The surgeons were also more satisfied with this method. episodes, whereas just 3 cases of the other group experienced A number of confounding factors could explain this it (P b .001). Postoperative nausea and vomiting were more discordance. (a) Tolerating the prone position for about an frequent among patients recovering from SA compared with hour, during disk surgery, is not possible unless the patient GA (20% vs 6%, P = .037). Conversely, in the day after the is sedated. One of the best sedative agents administered for operation, nausea and vomiting occurred 8% more in GA this purpose is propofol. It has short-term effects; and cases than SA ones, although it was not statistically therefore, the sedative effects disappear within a few minutes significant (P = .249). after the interruption of the drug infusion. The antivomiting Patients in the SA group required less analgesics effect of this drug even in low doses (10-15 mg) is well immediately after the operation, and the difference was known [10]; moreover, it has been shown that it can reduce statistically significant (62% vs 22%, P b .001). However, bleeding by decreasing the systemic vascular resistance by the need became similar on the day after the operation 15% to 25% [15]. Propofol infusion was administered as (74% vs 76%). the sedative agent in the group undergoing SA in several Table 4 Comparing SA vs GA outcomes of the RCTs conducted on patients undergoing laminectomy in the systematic review performed in Medline, Cochrane, Scopious, and advanced G-scholar using the key words GA, (and) SA, (and) comparison, (and) laminectomy, compared with the present study Study n N&V Bleeding RT AC Complication Jellish et al (1996) [7] 122 GA N SA GA N SA SA N GA GA N SA SA = GA Demeril et al (2003) [3] 60 GA N SA GA N SA SA = GA GA N SA GA = SA McLain et al (2004) [11] 200 GA N SA GA N SA SA N GA GA N SA GA N SA McLain et al (2005) [12] 400 GA N SA GA N SA SA N GA GA N SA GA N SA This series 100 SA N GA GA = SA SA = GA GA N SA GA = SA N&V indicates nausea and vomiting in the recovery room; bleeding, the amount of intraoperative bleeding; RT, recovery time; AC, analgesic consumption in the recovery room.
  • 64 S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 studies; however, the patients in the other group did not 7. It should also be kept in mind that the surgeons are not receive such an agent. Therefore, administration of the able to evaluate the patients' neurologic status propofol was one of the factors altering the results of those immediately after the operation in the SA because of studies [7,11,12]. In the present study, propofol was used as the motor block state that happens during this type of the sole hypnotic and sedative agent in both the GA and SA anesthesia. That is one of the major drawbacks of SA groups. (b) Inaccurate calculation of the patients' fluid for disk surgery. It is noteworthy that very few studies requirement was the second confounding factor cited in in this field have evaluated the surgeons' satisfaction those studies. The fluid infused during the operation is rate not only because there may be no standard scaling normally assumed by considering the patients' weight, technique for it but because close cooperation between the duration of anesthesia, the minimum NPO duration, the the anesthesiologist and the attending surgeon is amount of the fluid loss, the CVE, the third space, the necessary to develop a reliable VAS. insensible water loss, and the bleeding compensation. According to Jellish et al [7], the amount of infused fluid Along with these concerns, there are some other was reported to be approximately 800 1100 mL less than important points that reduce the anesthesiologists' prefe- the required amount. They also showed that the average rence for SA, such as: amount of bleeding and the duration of anesthesia were also reported to be more in the GA group. In other words, the 1. Although anesthesiologists are interested in SA as a required fluid was not completely compensated in the more reliable method, experience shows the prolonged abovementioned study; thus, the hemodynamic changes operation performed in the prone position under SA cannot exclusively be attributed to the kind of anesthesia increases the anesthesiologist's stress and anxiety. applied. (c) Regarding the operation time and the amount of 2. Heightening of the blocked level leading to apnea is blood loss during operation, both of them look to be another possible worrying complication using this “confounding factors” rather than independent variables method, compared with GA anesthesia. because the surgeons usually turn the patients into the prone 3. Managing an apneic patient, providing an airway position according to their own will and satisfaction, so no access, and placing an endotracheal tube in the prone neurosurgeon is actually blind about the patient allocation position are difficult. to either GA or SA group! That makes a major bias for the 4. In addition, the infusion of the anesthetic agent may be surgeon. First, the surgeon may take his/her time for a accompanied with amnesia; any decrease in the satisfactory and complete surgery without being worried sedation depth (which is common) is accompanied about the length of operation being inconvenient for the with involuntary, sudden movements in the patient's patient in the prone position. Second, the longer the upper body, resulting in possible nerve root injuries operation, the more will be those minimal changes in [9,21]. Cough and hiccups are also recurrently the amount of bleeding during operation. reported during this type of anesthesia [3,16]. According to the findings of the present study, each method has its own preferred characteristics: According to the abovementioned results, it could be concluded that GA causes less intraoperative bleeding 1. Considering the hemodynamic stability, the incidence accompanied by a higher hemodynamic stability; it also of bradycardia was equal in both methods. provides a relatively higher satisfactory condition for the 2. The prevalence of hypotension and, consequently, surgeon and the patient. It should be noted that an increased the administration of ephedrine were higher in SA; risk of bleeding, nausea, vomiting, and hemodynamic conversely, hypertension was more frequently instability is reported after a typical GA sedation using reported after the operation in the patients who had inhaled anesthetics, although the present study revealed that undergone GA. the administration of propofol via TIVA in these operations 3. The incidence of tachycardia was higher in GA, reduces the incidence of such adverse effects. occurring mainly during the intubation period. For- tunately, none of the 100 patients under study reported 5. Conclusion any complication due to the hemodynamic changes. 4. The average intraoperative bleeding and need for fluid The findings of the present study revealed that SA has no were not significantly different in the 2 groups. acceptable advantage over GA in lumbar disk surgery. 5. In the recovery room, the number of patients with pain Moreover, it could support the hypothesis that GA who needed analgesics was less in the SA group; this can reduce the related risks and complications in several could be due to the anesthetic agent's effect. aspects and rule out the first hypothesis suggested in 6. On the other hand, nausea and vomiting were more the introduction. prevalent among the patients recovering from SA However, further well-designed studies including more because of the unopposed parasympathetic activity sample cases are still needed to evaluate the accuracy of the occurring with this method [2]. abovementioned findings.
  • S.H. Sadrolsadat et al. / Surgical Neurology 71 (2009) 60–65 65 Acknowledgment [15] Reves JG, Glass PSA, Lubrasky DA, McEvoy MD. Intravenous non- opioid anesthetics. Miller's anesthesia. 6th Ed. UK: Elsevier Churchill We are indebted to the Research and Development Center Livingstone; 2005. p. 317-78. Chapter 10. of Sina Hospital for their support. [16] Riding JE. Minor complications of general anaesthesia. BJA 197;47: 91-101. [17] Riegel B, Alibert F, Becq MC, et al. Lumbar disc herniation with References surgical option: general versus local anesthesia. Agressologie 1994;34: 33-7. [1] Backofen JE, Schauble JR. Hemodynamic changes with prone [18] Scott NB, Kehlet H. Regional anesthesia and surgical morbidity. Br J positioning during general anaesthesia. Anesth Analg 1985;64:194. Surg 1988;75:299-304. [2] Brown DL. Spinal, epidural and caudal anesthesia. Miller's anesthesia. 6th [19] Silver DJ, Dunsmore RH, Dickson CM. Spinal anesthesia for lumbar ed. UK: Elsevier Churchill Livingstone; 2005. p. 1654-83. Chapter 43. disc surgery: review of 576 operations. Anesth Analg 1976;55: [3] Demeril CB, Kalayci M, Ozkocak I, et al. A prospective randomized 550-4. study comparing peri-operative outcome variables after epidural of [20] Tetzlaff JE, Dilger JA, Kodsy M, et al. Spinal anesthesia for elective general anesthesia for lumbar disc surgery. J Neurosurg Anesthesiol lumbar spine surgery. J Clin Anesth 1998;10:666-9. 2003;15(3):158-92. [21] Thorsen G. Neurological complications after spinal anesthesia and [4] Dripps RD, Vandam LD. Long term follow up of patients who received results from 2493 follow up cases. Acta Chir Scand Suppl 1947;121: 10098 spinal anesthetics: failure to discover major neurological 1-272. sequelae. JAMA 1954;156:1486-91. [5] Hassi N, Badaoui R, Cagny Bellet A, et al. Spinal anesthesia for disc herniation and lumbar laminectomy: apropos of 77 cases. Cah Anesthesiol 1995;43:21-5. [6] Jellish WS, Shea JF. Spinal anaesthesia for spinal surgery 2003;17: Commentary 332-4. [7] Jellish WS, Thalji Z, Stevenson K, Shea J. A prospective randomized study comparing short and intermediate term perioperative outcome How far we have come since the advent of general variables after spinal or general anesthesia for lumbar disk and anesthesia. The complications of ether anesthesia, in part at laminectomy surgery. Anesth Analg 1996;83:559-64. least, led to the development of regional anesthesia [8] Kakiuchi M. Reduction of blood loss during spinal surgery by epidural techniques as pioneered in the United States by John blockade under normotensive general anesthesia. Spine 1997;22: Bonica (http://www.painresearch.utah.edu/crc/CRCpage/ 889-94. [9] Kennedy F, Efron AS, Perry G. The grave spinal cord paralysis caused Bonica.html), especially for the pain of childbirth. Never- by spinal anesthesia. Surg Gynecol Obstet 1950;91:385-97. theless, improvements in the techniques of general [10] McCollum JS, Milligan KR, Dundee JW. The antiemetic action of anesthesia have proven the method as equal to or superior propofol. Anesthesia 1988;43:239-40. to regional anesthesia as is demonstrated in the present [11] Mclain R, Bell GR, Kalfas I, et al. Complications associated with study. Surgeons are clearly more comfortable operating lumbar laminectomy: a comparison of spinal versus general anesthesia. Spine 2004;29:2542-7. on a paralyzed asleep patient as this study also confirmed. [12] McLain RF, Kalfas I, Bell GR, et al. Comparison of spinal and general The authors are to be commended for an appropriate and anesthesia in lumbar laminectomy surgery: a case controlled analysis useful study. of 400 patients. J Neurosurg Spine 2005;2:17-22. [13] Nazon D, Abergel G, Hatem CM. Critical care in orthopedic and spine Ron Pawl, MD surgery. Crit Care Clin 2003;19:33-53. [14] Phillips OC, Ebner H, Nelson AT. Neurological complications Center for Pain Treatment and Rehabilitation following spinal anesthesia with lidocaine: a prospective review of Lake Forest Hospital 10440 cases. Anesthesiology 1969;30:284-9. Lake Forest, IL 60045, USA