Does pregnancy protect against intrathecal lidocaine-induced transient neurologic symptoms?

We investigated the incidence of transient neurologic symptoms (TNS) after the use of hyperbaric lidocaine as compared with hyperbaric bupivacaine in patients undergoing cesarean delivery under spinal anesthesia. Two hundred women scheduled for cesarean delivery were randomly allocated to receive spinal anesthesia with 75 mg hyperbaric lidocaine 5% (n = 100) or 12 mg hyperbaric bupivacaine 0.75% (n = 100). Spinal anesthesia was administered to all patients in the sitting position with a 25-gauge Whitacre needle. The level of sensory blockade, time to full recovery, and intraoperative hemodynamic profile were noted in all patients. The patients were interviewed postoperatively for three consecutive days to detect the occurrence of TNS. The incidence of TNS was zero (95% confidence interval 0%--3%) in both the Lidocaine and the Bupivacaine Groups. Our results indicate that the frequency of postoperative TNS does not exceed 3% in patients undergoing cesarean delivery at term using hyperbaric lidocaine 5% or hyperbaric bupivacaine 0.75%.     

The incidence of transient radicular irritation after spinal anesthesia in obstetric patients

Background and Objectives. Transient radicular irritation (TRI) has been described after spinal anesthesia, particularly with 5% hyperbaric spinal lidocaine. The purpose of this study was to determine the incidence of TRI in obstetric patients. Methods. All obstetric patients undergoing spinal anesthesia during a 9-month period were enrolled in the study (n = 303). Details of the anesthetic technique were recorded at the time of anesthesia. A blinded anesthesia nurse contacted each patient on post-operative day 2 and asked about symptoms of TRI. Results. Most patients received either intrathecal hyperbaric bupivacaine 0.75% (n = 232) or lidocaine 5% (n = 67) through pencil-point needles. Cerebrospinal fluid was used to dilute the spinal lidocaine in 63% of patients. Patients receiving bupivacaine were more often in the supine position, underwent significantly longer procedures, and more often received intrathecal opioid. The incidence of TRI after lidocaine spinal anesthesia was 0% (95% confidence interval 0–4.5%). Conclusions. The incidence of TRI after spinal lidocaine anesthesia in the obstetric population is low.     

Transient neurologic symptoms after spinal anesthesia with lidocaine versus other local anesthetics: a systematic review of randomized, controlled trials

Lidocaine has been used for spinal anesthesia since 1948, seemingly without causing concern. However, during the last 10 years, a number of reports have appeared implicating lidocaine as a possible cause of neurologic complications after spinal anesthesia. Follow-up of patients who received uncomplicated spinal anesthesia revealed that some of them developed pain in the lower extremities--transient neurologic symptoms (TNS). In this study, we sought to compare the frequency of 1) TNS and 2) neurologic complications after spinal anesthesia with lidocaine with that after other local anesthetics. Published trials were identified by computerized searches of The Cochrane Library, MEDLINE, LILAC, and EMBASE and by checking the reference lists of trials and review articles. The search identified 14 trials reporting 1347 patients, 117 of whom developed TNS. None of these patients showed signs of neurologic complications. The relative risk for developing TNS after spinal anesthesia with lidocaine was higher than with other local anesthetics (bupivacaine, prilocaine, procaine, and mepivacaine), i.e., 4.35 (95% confidence interval, 1.98-9.54). There was no evidence that this painful condition was associated with any neurologic pathology; in all patients, the symptoms disappeared spontaneously by the 10th postoperative day.     

Transient Neurologic Symptoms after Spinal Anesthesia: An Epidemiologic Study of 1,863 Patients

Background: Recent evidence suggests that transient neurologic symptoms commonly follow lidocaine spinal anesthesia. However, information concerning factors that affect their occurrence is limited. Accordingly, to evaluate many potential risk factors, the authors undertook a prospective, multicenter, epidemiologic study.

Methods: On a voluntary basis, anesthetists at 15 participating centers forwarded a data sheet on patients who had spinal anesthesia to a research nurse blinded to the details of anesthesia and surgery. A subset was randomly selected for follow-up. The pressure of transient neurologic symptoms, defined as leg or buttock pain, was the principal outcome variable. Logistic regression was used to control for potential confounders, and adjusted odds ratios and confidence intervals were used to estimate relative risk.

Results: During a 14-month period, 1,863 patients were studied, of whom 47% received lidocaine, 40% bupivacaine, and 13% tetracaine. Patients given lidocaine were at higher risk for symptoms compared with those receiving bupivacaine (relative risk, 5.1; 95% CI, 2.5 to 10.2) or tetracaine (relative risk, 3.2; 95% CI, 1.04 to 9.84). For patients who received lidocaine, the relative risk of transient neurologic symptoms was 2.6 (95% CI, 1.5 to 4.5) with the lithotomy position compared with other positions, 3.6 (95% CI, 1.9 to 6.8), for outpatients compared with inpatients, and 1.6 (95% CI, 1 to 2.5) for obese (body mass index >30) compared with nonobese patients.     

Dilution of Spinal Lidocaine Does Not Alter the Incidence of Transient Neurologic Symptoms

Background: Although it has been suggested that the dilution of 5% hyperbaric lidocaine before injection for spinal anesthesia may decrease the incidence of transient neurologic symptoms, previous studies have not noted a decreased incidence between 5% and 2% lidocaine. The aim of the current study was to determine whether the incidence of transient neurologic symptoms could be altered by further diluting spinal lidocaine from 2.0% to 0.5%.

Methods: One hundred nine patients with American Society of Anesthesiologist physical status 1 or 2 undergoing outpatient knee arthroscopy were randomized in a double-blind fashion to receive 50 mg hyperbaric spinal lidocaine as a 2.0%, 1.0%, or 0.5% concentration. On the third postoperative day, patients were contacted by a blinded investigator and questioned regarding the incidence of postoperative complications, including transient neurologic symptoms, defined as pain or dysthesia in one or both buttocks or legs occurring within 24 h of surgery.

Results: The incidence of transient neurologic symptoms did not differ among patients receiving 2.0% (incidence of 15.8%), 1.0% (incidence of 22.2%), and 0.5% (incidence of 17.1%) lidocaine (P = 0.756).     

Transient Neurologic Symptoms after Spinal Anesthesia: A Lower Incidence with Prilocaine and Bupivacaine than with Lidocaine

Background: Recent evidence suggests that transient neurologic symptoms (TNSs) frequently follow lidocaine spinal anesthesia but are infrequent with bupivacaine. However, identification of a short-acting local anesthetic to substitute for lidocaine for brief surgical procedures remains an important goal. Prilocaine is an amide local anesthetic with a duration of action similar to that of lidocaine. Accordingly, the present, prospective double-blind study compares prilocaine with lidocaine and bupivacaine with respect to duration of action and relative risk of TNSs.

Methods: Ninety patients classified as American Society of Anesthesiologists physical status I or II who were scheduled for short gynecologic procedures under spinal anesthesia were randomly allocated to receive 2.5 ml 2% lidocaine in 7.5% glucose, 2% prilocaine in 7.5% glucose, or 0.5% bupivacaine in 7.5% glucose. All solutions were provided in blinded vials by the hospital pharmacy. Details of spinal puncture, extension and regression of spinal block, and the times to reach discharge criteria were noted. In the evening of postoperative day 1, patients were evaluated for TNSs by a physician unaware of the drug administered and the details of the anesthetic procedure.

Results: Nine of 30 patients receiving lidocaine experienced TNSs, 1 of 30 patients receiving prilocaine (P = 0.03) had them, and none of 30 patients receiving bupivacaine had TNSs. Times to ambulate and to void were similar after lidocaine and prilocaine (150 vs. 165 min and 238 vs. 253 min, respectively) but prolonged after bupivacaine (200 and 299 min, respectively; P < 0.05).     

Peripheral neurologic deficits in relation to subarachnoid or epidural administration of local anesthetics for surgery

Background: Recent case reports have suggested that subarachnoid or epidural administration of local anesthetics may cause peripheral neurologic deficits. Methods: To describe the course and evaluate possible risk factors of such reactions, 21 reports in the Swedish adverse drug reactions register were reviewed. Results: The reports concerned subarachnoid administration of hyperbaric lidocaine (n=9), plain bupivacaine (n=4), hyperbaric bupivacaine (n=2), bupivacaine with epinephrine (n=1) and mepivacaine (n=l), and epidural administration of bupivacaine (n=2) and mepivacaine (n=2).Pain in the lower extremities was reported in 12 patients (57%)and paresthesias/hypesthesias were reported in 11 patients (52%). Seven reports (33%)concerned low back pain or abdominal pain from Th9-ThlO and downwards. Urinary incontinence was reported in 3 patients, fecal incontinence in 2 patients, and erectile dysfunction, loss of sensation of full bladder and quadriceps muscle paresis were each reported in one patient. Two clinically distinct subgroups of patients were identified, one group with reversible nerve root affection which disappeared within 2 weeks and one group with apparently irreversible nerve root affection, still persistent after 1 month to 4 years. h the group with reversible root symptoms, none had motor deficits, whereas 50% had motor deficits in the group with irreversible symptoms. Possible risk factors include concomitant peripheral neurologic disease and use of other drugs associated with neurotoxicity. Conclusion: This database study does not contain complete information for the cases reported, and a causal relationship between subarachnoid or epidural administration of local anesthetics and neurologic deficits therefore remains uncertain. The increase in the number of reports on lidocaine after the introduction of very fine-bore spinal needles is consistent with the suspicion that lidocaine at the concentration 50 mg/ml is neuro-toxic and that it may not be diluted rapidly enough in the cere-brospinal fluid when injected through such needles.     

Transient radicular pain following spinal anesthesia: review of the literature and report of a case involving 2% lidocaine

Recent reports of transient radicular irritation following intrathecal administration of 5% lidocaine in 7.5% dextrose, a common drug choice in many obstetric centers, have generated concern that its use for single injection spinal anesthesia can result in transient neurologic toxicity. Accordingly, many have advocated dilution of this anesthetic solution prior to subarachnoid administration. The present report describes a case in which transient neurologic symptoms occurred following intrathecal injection of a solution containing approximately 2% lidocaine. The similarity of the present case to those previously reported implies a common etiology and suggests that risk is not restricted to the use of 5% lidocaine with 7.5% glucose. It underscores the need for carefully controlled prospective evaluation of the factors that affect transient neurologic dysfunction following spinal anesthesia.     

Determination of the Full Dose-Response Relation of Intrathecal Bupivacaine, Levobupivacaine, and Ropivacaine, Combined with Sufentanil, for Labor Analgesia

Background: Ropivacaine and levobupivacaine are local anesthetics that produce less motor block and greater sensory-motor separation when compared with equal milligram doses of bupivacaine. Although minimum local analgesic concentration studies suggested that they are less potent than bupivacaine, full dose-response studies have not been performed. The current trial describes the dose-response relation of levobupivacaine, ropivacaine, and bupivacaine, combined with sufentanil, when used for intrathecal labor analgesia.

Methods: Four hundred fifty term parturients in active labor were included in this double-blind, randomized trial. Combined spinal-epidural anesthesia was performed, and ropivacaine, levobupivacaine, or bupivacaine was intrathecally administered in a dose of 1.0, 1.5, 2.0, 2.5, 3.0, or 3.5 mg, always combined with 1.5 [mu]g sufentanil. Patients were considered responders to spinal analgesia if the visual analog scale score for pain was less than 25 mm within 15 min and the visual analog scale score remained less than 25 mm for 45 min. Patient demographics, obstetric data, maternal side effects, and fetal and neonatal well-being were noted. Group-specific dose-response curves were constructed using a probit regression model.

Results: The ED95 of bupivacaine was 3.3 mg (95% confidence interval, 2.9-4.1). The ED95s of ropivacaine and levobupivacaine were 4.8 mg (95% confidence interval, 4.0-6.7) and 5.0 mg (95% confidence interval, 4.1-7.0), respectively. Racemic bupivacaine was significantly more potent than ropivacaine (P = 0.0027) and levobupivacaine (P = 0.0006). Ropivacaine and levobupivacaine were of similar potency (P = 0.91).     

Should intrathecal lidocaine be used in the 21st century?

Hyperbaric 5% lidocaine has been available for intrathecal use since 1954. The initial studies concluded that it was a safe drug for short procedures. Recently, the use of this drug for spinal anesthesia has been questioned. There were cases of cauda equina syndrome following its use for continuous spinal anesthesia. Following these occurrences, it was felt that lidocaine should not be used for continuous spinal anesthesia, rather for single-shot spinal anesthesia only. Intense follow-up of patients receiving intrathecal lidocaine for single-shot spinal anesthesia revealed a higher incidence of back pain radiating to the thighs and legs as compared to other drugs or general anesthesia. Although these symptoms have been linked to the drug, there were other factors affecting the incidence. Lithotomy position was a more significant predictor for developing these symptoms. Furthermore, there are seven cases of cauda equina syndrome following single-shot hyperbaric lidocaine. Cauda equina syndrome is a permanent disability. It occurred in patients of varying ages and with doses ranging from 60 mg to 120 mg. There are safe alternatives to lidocaine for outpatient spinal anesthesia, such as bupivacaine, prilocaine, or mepivacaine. These drugs have a lower incidence of transient neurologic symptoms and do not delay discharge. Given the possibility of permanent neurologic injury and given that safe alternatives exist, one has to question whether intrathecal lidocaine should still be used in the 21st century.     

Incidence of Transient Neurologic Symptoms after Hyperbaric Subarachnoid Anesthesia with 5% Lidocaine and 5% Prilocaine

Background: Hyperbaric 5% lidocaine has been associated with transient neurologic symptoms (TNSs) after spinal anesthesia. A prospective, masked, randomized study was conducted to compare the incidence of TNSs after spinal anesthesia with hyperbaric 5% lidocaine or 5% prilocaine to assess the utility of prilocaine as an alternative to lidocaine in patients having short surgical procedures.

Methods: The number of patients to be enrolled (100 per group) was determined by power analysis (80%, P = 0.05) considering an incidence of TNSs after spinal anesthesia with lidocaine of at least 11% according to data reported in other studies. Two hundred patients scheduled for elective surgery expected to last < 60 min were allocated at random to receive spinal anesthesia with hyperbaric 5% lidocaine or hyperbaric 5% prilocaine. Three to 5 days after spinal anesthesia, all patients were interviewed by an anesthesiologist who was blinded to the group assignment and details of the anesthetic and surgical technique using a standardized symptom checklist. Patients with symptoms underwent neurologic examination.

Results: Both groups were comparable with regard to demographic data and details of the surgical and anesthetic procedures. The incidence of TNSs in both groups was low and differences were not found (4% in the lidocaine group and 1% in the prilocaine group). The mean age of patients with TNSs (58 yr) was higher than that of patients without TNSs (48 yr; P < 0.05). No relation with any of the other variables was found.     

Determination of the full dose-response relation of intrathecal bupivacaine, levobupivacaine, and ropivacaine, combined with sufentanil, for labor analgesia

BACKGROUND: Ropivacaine and levobupivacaine are local anesthetics that produce less motor block and greater sensory-motor separation when compared with equal milligram doses of bupivacaine. Although minimum local analgesic concentration studies suggested that they are less potent than bupivacaine, full dose-response studies have not been performed. The current trial describes the dose-response relation of levobupivacaine, ropivacaine, and bupivacaine, combined with sufentanil, when used for intrathecal labor analgesia. METHODS: Four hundred fifty term parturients in active labor were included in this double-blind, randomized trial. Combined spinal-epidural anesthesia was performed, and ropivacaine, levobupivacaine, or bupivacaine was intrathecally administered in a dose of 1.0, 1.5, 2.0, 2.5, 3.0, or 3.5 mg, always combined with 1.5 microg sufentanil. Patients were considered responders to spinal analgesia if the visual analog scale score for pain was less than 25 mm within 15 min and the visual analog scale score remained less than 25 mm for 45 min. Patient demographics, obstetric data, maternal side effects, and fetal and neonatal well-being were noted. Group-specific dose-response curves were constructed using a probit regression model. RESULTS: The ED95 of bupivacaine was 3.3 mg (95% confidence interval, 2.9-4.1). The ED95s of ropivacaine and levobupivacaine were 4.8 mg (95% confidence interval, 4.0-6.7) and 5.0 mg (95% confidence interval, 4.1-7.0), respectively. Racemic bupivacaine was significantly more potent than ropivacaine (P=0.0027) and levobupivacaine (P=0.0006). Ropivacaine and levobupivacaine were of similar potency (P=0.91). CONCLUSIONS: This full dose-response study suggests that ropivacaine and levobupivacaine are of similar potency, whereas bupivacaine is more potent than both other drugs.     

Neurologic sequelae after caesarean section

BACKGROUND: Because pregnancy increases the sensitivity of nervous tissue to local anaesthetics, pregnant patients may be at higher risk of developing neurologic deficits after spinal block than non-pregnant patients. Therefore, we evaluated prospectively the incidence and type of neurologic symptoms after spinal anaesthesia with hyperbaric bupivacaine for caesarean section. METHODS: In this prospective follow-up study we recorded neurologic complications during anaesthesia and postoperatively until discharge from the hospital of 219 patients, who underwent caesarean section under spinal anaesthesia with hyperbaric bupivacaine (5 mg/ml, mean 13 mg). The patients filled in a questionnaire on the first and fifth postoperative days. In the case of complaints typical of neurologic symptoms they were checked first by the anaesthesiologist and, in the case of persistent symptoms, afterwards additionally by a neurologist. RESULTS: Twenty-six of 219 patients were not included in the further evaluation because of incomplete return of their questionnaires. Seventeen mothers (8.8%) complained of transient neurologic symptoms (TNSs), lasting mostly 1-2 days, in the buttocks and/or legs during the first three postoperative days. Eleven patients (5.7%) complained of postdural puncture headache. Two patients (emergency caesarean section because of protracted labour in one and elective caesarean section because of previous caesarean section in the other) complained of persisting pain or sensory abnormalities. Neither of them felt paraesthesia during lumbar puncture. CONCLUSION: Women after caesarean section under a spinal block seem to suffer more often from TNSs than non-pregnant women. The conclusions are, however, uncertain since we had no control group operated on under other than spinal anaesthesia. The persisting neurologic symptoms in two patients might also be due to the obstetric procedure itself. To find out about the validity and possible underlying causes of our results, we need randomised studies with control groups receiving epidural or general anaesthesia.     

Subarachnoid small-dose bupivacaine versus lidocaine for cervical cerclage

Cervical cerclage is often performed as an outpatient procedure under subarachnoid anesthesia. Lidocaine was historically the drug of choice for short procedures but has fallen out of favor because of concerns of transient neurologic symptoms (TNS). We performed this study to determine whether small-dose bupivacaine is an acceptable alternative to lidocaine for cervical cerclage. We randomized 59 women to receive either subarachnoid isobaric lidocaine 30 mg or hyperbaric bupivacaine 5.25 mg. Fentanyl 20 micro g was added to both local anesthetics, and the total volume was diluted to 3 mL with 0.9% saline. Onset and highest dermatomal level of sensory block; quality of anesthesia; hypotension; and times until T12 regression, return of lower extremity motor function, ambulation, and micturition were recorded. Symptoms of TNS were evaluated by telephone interview 24 h after surgery. We did not find any significant difference in onset or recovery times between the groups, with the exception of a longer duration until return of lower extremity motor strength in the lidocaine group. Symptoms consistent with TNS that resolved spontaneously within 48 h were reported by two women in the lidocaine group but by none in the bupivacaine group. We conclude that subarachnoid bupivacaine offers a satisfactory alternative to subarachnoid lidocaine for cervical cerclage. IMPLICATIONS: We found that small-dose subarachnoid bupivacaine (5.25 mg) with fentanyl 20 micro g provides reliable anesthesia for cervical cerclage and exhibits a pharmacodynamic profile similar to that of small-dose lidocaine.     

Postpartum neurologic symptoms following single-shot spinal block for labour analgesia

BACKGROUND: As part of a quality assurance program, we investigated the incidence of postpartum neurologic symptoms in multiparous parturients receiving spinal block for labour analgesia, now in routine use in our labour ward. METHODS: Two hundred and twenty-nine consecutive multiparous parturients presenting for vaginal delivery and requesting spinal analgesia were asked to participate in this prospective study. All parturients received our standard intrathecal analgesia (ITA): 2.5 mg bupivacaine (1 ml) + 25 microg fentanyl (0.5 ml) using a 27-gauge Quincke-type needle. The patients filled in a questionnaire on the first day after delivery and again upon discharge. Complaints typical of neurologic sequelae were noted and a neurologic examination was performed, if necessary. All patients with postdural puncture headache (PDPH) and transient neurologic symptoms (TNSs) were interviewed by telephone 2 weeks after discharge to determine the course of the symptoms. RESULTS: Two hundred and twelve parturients were included in the study. Eighteen (8.5%) parturients complained of PDPH, the severity of which was mild in eight (4%), moderate in seven (3%), and severe in three (1%) patients, respectively. Fifteen (7%) mothers were treated with analgesics or bedrest only. Three (1%) patients were given an epidural blood patch. The paramedian approach was associated with the development of PDPH (P = 0.04). Transient neurologic symptoms were experienced by nine (4.2%) mothers, lasting 1-3 days, mostly presenting as bilateral pain in the buttocks or thighs. One parturient suffered from paraesthesia of the left foot lasting for 3 days. Forty (19%) mothers complained of non-postural headache and 28 (13%) of new-onset back pain. Three mothers (1%) would not want to receive a further spinal block. CONCLUSION: Transient neurologic symptoms (TNSs) after spinal block occurred infrequently. The incidence of PDPH was higher than in the obstetric population in general and calls for re-evaluation of our spinal block methods. Despite the occurrence of neurologic sequelae, patient acceptability was high.     

蛛网膜下腔注射罗哌卡因与布比卡因运动神经阻滞效力的比较

目的 比较蛛网膜下腔注射罗哌卡因与布比卡因的运动神经阻滞效力.方法 择期脊椎.硬膜外麻醉下拟行泌尿外科腔镜手术患者60例,年龄18～64岁,体重46～75 kg,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将患者随机分为2组(n=30):0.5%罗哌卡因组和0.5%布比卡因组.按照序贯法进行试验,阻滞有效,下一例患者采用低一级剂量,阻滞无效,下一例患者采用高一级剂量,初始剂量均为4 mg,剂量梯度1 mg,阻滞有效的标准:蛛网膜下腔给药后5或10 min时任一下肢的任一种运动神经阻滞评分>0分.采用序贯法计算蛛网膜下腔注射罗哌卡因或布比卡因运动神经阻滞的半数有效剂量(ED50)及其95%置信区间.结果 患者蛛网膜下腔注射罗哌卡因和布比卡因运动神经阻滞的ED50及其95%置信区间分别为6.68(6.27～7.13)mg和4.07(3.56～4.47)mg,效力比为O.61.结论 患者蛛网膜下腔注射罗哌卡因运动神经阻滞效力低于布比卡因.

Abstract：

Objective To determine the median effective doae (ED50) for motor block after intrathecal ropivacaine and bupivacaine. Methods Sixty ASA Ⅰ or Ⅱ patients, aged 18-64, weighing 46-75 kg, undergoing elective urological surgery under combined spinal-epidural anesthesia, were randomized into 2 groups ( n = 30each) receiving intrathecal 0.5% ropivacaine and 0.5% bupivacaine respectively. The ED50 was determined by up-down sequential allocation. The initial dose was 4 mg. Each time the dose increased/decreased by 1 mg. Efficacy was determined by the occurrence of any motor block in either lower extremity (modified Bromage scale > 0)within 5 or 10 min after the spinal injection. Results The intrathecal ED50 for motor block was 6.68 mg for ropivacaine (95% confidence interval 6.27-7.13 mg) and 4.07 mg for bupivacaine (95% confidence interval 3.56-4.47mg) . The relative motor blocking potency ratio was ropivacaine/bupivacaine 0.61. Conclusion The potency of intrathecal ropivacaine is lower than that of bupivacaine for motor block.     

Prospective Study of the Incidence of Transient Radicular Irritation in Patients Undergoing Spinal Anesthesia

Background: There is considerable controversy regarding the role of subarachnoid 5% hyperbaric lidocaine in the syndrome transient radicular irritation (TRI). This randomized, double-blinded, prospective study was designed to determine the incidence of TRI and identify factors possibly contributing to its development.

Methods: One hundred fifty-nine ASA physical status 1 or 2 patients undergoing outpatient knee arthroscopy or unilateral inguinal hernia repair were prospectively randomized to receive spinal anesthesia with 5% hyperbaric lidocaine with epinephrine (60 mg with 0.2 mg epinephrine for arthroscopy or 75 mg with 0.2 mg epinephrine for hernia repair), 2% isobaric lidocaine without epinephrine (60 mg for arthroscopy or 75 mg for hernia repair), or 0.75% hyperbaric bupivacaine without epinephrine (7.5 mg for arthroscopy or 9.0 mg for hernia repair) in a double-blinded fashion. On the 3rd postoperative day, patients were contacted by a blinded investigator and questioned regarding the incidence of postoperative complications including TRI, defined as back pain with radiation down one or both buttocks or legs occurring within 24 h after surgery. Postoperatively, time from injection to block resolution, ambulation, voiding, and ready for discharge were recorded by a postanesthesia care unit nurse blinded to the group assignment.

Results: The incidence of TRI was greater in patients receiving lidocaine than in those receiving bupivacaine (16% vs. 0%; P = 0.003). There was no difference in the incidence of TRI between the patients receiving 59% hyperbaric lidocaine with epinephrine and those receiving 2% isobaric lidocaine without epinephrine (16% vs. 16%; P = 0.98). The incidence of TRI was greater in patients undergoing arthroscopy than in those undergoing hernia repair (13% vs. 5%; P = 0.04). There was no difference in discharge times in patients receiving bupivacaine versus those receiving hyperbaric lidocaine with epinephrine (292 vs. 322 min; P = 0.61).     

Spinal nerve function in five volunteers experiencing transient neurologic symptoms after lidocaine subarachnoid anesthesia

The etiology of transient neurologic symptoms (TNS) after 5% lidocaine spinal anesthesia remains undetermined. Previous case reports have shown that patients acutely experiencing TNS have no abnormalities on neurologic examination or magnetic resonance imaging. The aim of our study was to determine whether volunteers with TNS would exhibit abnormalities in spinal nerve electrophysiology. Twelve volunteers with no history of back pain or neurologic disease underwent baseline electromyography (EMG), nerve conduction studies, and somatosensory-evoked potential (SSEP) testing. Then, the volunteers were administered 50 mg of 5% hyperbaric lidocaine spinal anesthesia and were placed in a low lithotomy position (legs on four pillows). The next day, all volunteers underwent follow-up EMG, nerve conduction, and SSEP testing and were questioned and examined for the presence of complications including TNS (defined as pain or dysthesia in one or both buttocks or legs occurring within 24 h of spinal anesthesia). Volunteers who had TNS underwent additional EMG testing 4-6 wk later. Five of the 12 volunteers reported TNS. No volunteer had an abnormal EMG, nerve conduction study, or SSEP at 24 h follow up, nor were there any changes in EMG studies at delayed testing in the five volunteers experiencing TNS. On statistical analysis, the right peroneal and the right tibial nerve differed significantly for all volunteers from pre- to postspinal testing. When comparing pre- and postspinal testing of the TNS and non-TNS volunteers, statistically significant changes occurred in the nerve conduction tests of the right peroneal and left tibial nerve. There was no difference in measurements of F response, H reflex latency, amplitude, or velocity for either leg. Multivariate analysis of variance showed no significant difference between TNS and non-TNS volunteers for the changes in the nine nerve conduction tests when considered together (P = 0.4). We conclude that acute TNS after lidocaine spinal anesthesia did not result in consistent abnormalities detectable by EMG, nerve conduction studies, or SSEP in five volunteers. Implications: Electrophysiologic testing in volunteers experiencing transient neurologic symptoms is not abnormal.     

The influence of ambulation time on the incidence of transient neurologic symptoms after lidocaine spinal anesthesia

The cause of transient neurologic symptoms (TNSs) after lidocaine spinal anesthesia remains unclear. It has been proposed that early ambulation after spinal anesthesia contributes to the development of TNSs. We evaluated the influence of ambulation time on the occurrence of TNSs after spinal anesthesia with 50 mg of 2% plain lidocaine for knee arthroscopy. One-hundred-twenty patients undergoing knee arthroscopy (ASA physical status 1-2) were randomized into 3 groups, i.e., early (Group E), 6-h (Group 6-h), or late ambulation (Group L) groups. In Group E, ambulation was allowed as early as possible after regression of spinal block (on average 229 +/- 21 min; range, 135-247 min). In Group 6-h, the patients remained in bed for approximately 6 h after the block and in Group L until the next morning. The patient groups were comparable with respect to demographic, anesthetic, and surgical variables. The overall incidence of TNSs was 16%. TNSs occurred in 3 patients of Group E (7.5%), in 11 patients of Group 6-h (28%), and in 5 patients of Group L (13%). No significant differences were detected between the patients with and without TNSs. Early ambulation was not found to be a risk factor for TNSs after spinal anesthesia with 50 mg of 2% lidocaine. IMPLICATIONS: This study shows that early ambulation time does not increase the incidence of transient neurologic symptoms after spinal anesthesia with 50 mg of 2% lidocaine for elective knee arthroscopy.