Transient neurological symptoms after spinal anaesthesia with hyperbaric 5% lidocaine or general anaesthesia

Spinal Anesthesia for Primary Hip and Knee Arthroplasty: Comparative Rates of Transient Neurological Symptoms and Urinary Retention using Lidocaine, Mepivacaine, and Bupivacaine

BACKGROUND

Short-acting spinal anesthetics enable rapid recovery hip and knee arthroplasty, however concerns with transient neurological symptoms (TNS) cause some to avoid using lidocaine. Post-operative urinary retention (POUR) is also a concern with spinal anesthesia. We sought to study the comparative rates of TNS and POUR between lidocaine, mepivacaine, and bupivacaine in a high-volume hip and knee arthroplasty setting.

METHODS

Data for 1,217 primary THA, TKA, and UKA cases were reviewed and grouped by spinal anesthetic agent (Lidocaine, Mepivacaine, or Bupivacaine). Of the 1,217 cases, utilization was 523 Lidocaine, 573 Mepivacaine, and 121 Bupivacaine. The incidence of TNS and POUR requiring catheterization was measured both by clinical evaluation as well as a questionnaire sent to patients 14 days postoperatively.

RESULTS

The overall rate of TNS was 8%. With the numbers available, there was no difference in rates of TNS between groups (6.9% Lidocaine, 9.2% Mepivacaine, and 4.1% Bupivacaine; P=0.297). There was no difference in rates of TNS or POUR between THA and TKA/UKA. Bupivacaine had a significantly higher rate of urinary retention (9.1%; P<0.001) than mepivacaine (2.8%) or lidocaine (1.5%).

CONCLUSIONS

This study showed no difference in the rate of TNS between the 3 common agents used in spinal anesthesia. Short-acting spinal anesthetics such as lidocaine and mepivacaine can lower the rate of POUR requiring catheterization helping to enable rapid recovery hip and knee arthroplasty.

Transient neurological symptoms (TNS) following spinal anaesthesia with lidocaine versus other local anaesthetics in adult surgical patients: a network meta-analysis

BACKGROUND

Spinal anaesthesia has been implicated as one of the possible causes of neurological complications following surgical procedures. This painful condition, occurring during the immediate postoperative period, is termed transient neurological symptoms (TNS) and is typically observed after the use of spinal lidocaine. Alternatives to lidocaine that can provide high-quality anaesthesia without TNS development are needed. This review was originally published in 2005, and last updated in 2009.

OBJECTIVES

To determine the frequency of TNS after spinal anaesthesia with lidocaine and compare it with other types of local anaesthetics by performing a meta-analysis for all pair-wise comparisons, and conducting network meta-analysis (NMA) to rank interventions.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Elsevier Embase, and LILACS on 25 November 2018. We searched clinical trial registries and handsearched the reference lists of trials and review articles.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials comparing the frequency of TNS after spinal anaesthesia with lidocaine to other local anaesthetics. Studies had to have two or more arms that used distinct local anaesthetics (irrespective of the concentration and baricity of the solution) for spinal anaesthesia in preparation for surgery. We included adults who received spinal anaesthesia and considered all pregnant participants as a subgroup. The follow-up period for TNS was at least 24 hours.

DATA COLLECTION AND ANALYSIS

Four review authors independently assessed studies for inclusion. Three review authors independently evaluated the quality of the relevant studies and extracted the data from the included studies. We performed meta-analysis for all pair-wise comparisons of local anaesthetics, as well as NMA. We used an inverse variance weighting for summary statistics and a random-effects model as we expected methodological and clinical heterogeneity across the included studies resulting in varying effect sizes between studies of pair-wise comparisons. The NMA used all included studies based on a graph theoretical approach within a frequentist framework. Finally, we ranked the competing treatments by P scores.

MAIN RESULTS

The analysis included 24 trials reporting on 2226 participants of whom 239 developed TNS. Two studies are awaiting classification and one is ongoing. Included studies mostly had unclear to high risk of bias. The NMA included 24 studies and eight different local anaesthetics; the number of pair-wise comparisons was 32 and the number of different pair-wise comparisons was 11. This analysis showed that, compared to lidocaine, the risk ratio (RR) of TNS was lower for bupivacaine, levobupivacaine, prilocaine, procaine, and ropivacaine with RRs in the range of 0.10 to 0.23 while 2-chloroprocaine and mepivacaine did not differ in terms of RR of TNS development compared to lidocaine. Pair-wise meta-analysis showed that compared with lidocaine, most local anaesthetics were associated with a reduced risk of TNS development (except 2-chloroprocaine and mepivacaine) (bupivacaine: RR 0.16, 95% confidence interval (CI) 0.09 to 0.28; 12 studies; moderate-quality evidence; 2-chloroprocaine: RR 0.09, 95% CI 0.01 to 1.51; 2 studies; low-quality evidence; levobupivacaine: RR 0.13, 95% CI 0.02 to 0.69; 2 studies; low-quality evidence; mepivacaine: RR 1.01, 95% CI 0.18 to 5.82; 4 studies; very low-quality evidence; prilocaine: RR 0.18, 95% CI 0.07 to 0.49; 4 studies; moderate-quality evidence; procaine: RR 0.14, 95% CI 0.04 to 0.52; 2 studies; moderate-quality evidence; ropivacaine: RR 0.10, 95% CI 0.01 to 0.78; 2 studies; low-quality evidence). We were unable to perform any of our planned subgroup analyses due to the low number of TNS events.

AUTHORS' CONCLUSIONS

Results from both NMA and pair-wise meta-analysis indicate that the risk of developing TNS after spinal anaesthesia is lower when bupivacaine, levobupivacaine, prilocaine, procaine, and ropivacaine are used compared to lidocaine. The use of 2-chloroprocaine and mepivacaine had a similar risk to lidocaine in terms of TNS development after spinal anaesthesia. Patients should be informed of TNS as a possible adverse effect of local anaesthesia with lidocaine and the choice of anaesthetic agent should be based on the specific clinical context and parameters such as the expected duration of the procedure and the quality of anaesthesia. Due to the very low- to moderate-quality evidence (GRADE), future research efforts in this field are required to assess alternatives to lidocaine that would be able to provide high-quality anaesthesia without TNS development. The two studies awaiting classification and one ongoing study may alter the conclusions of the review once assessed.

Wipeout period of spinal anesthesia in hemorrhoidectomy in relation to Prakriti: An observational study

Background:

A maximum number of hemorrhoidectomies are performed under spinal anesthesia. However, the effect of spinal anesthesia varies from person to person due to difference in their physical and psychological properties, which is well explained in Ayurveda as Prakriti (physiology of an individual). In this study, we have tried to establish a relation between wipeout period of spinal anesthesia and different Prakriti.

Objectives:

To observe wipeout period of spinal anesthesia in hemorrhoidectomy in relation to different Prakriti.

Materials and Methods:

A total of 30 individuals who underwent hemorrhoidectomy under spinal anesthesia were selected for the study and their Prakriti was assessed as per the standard Prakriti assessment chart before surgery. Apart from demographic data, pain assessment was also recorded by following visual analog scale. Postoperative follow-up was done until the wipeout effect of spinal anesthesia was observed. GraphPad Prism software was used to analyze the data; P < 0.05 was considered statistically significant.

Results:

Male predominance was observed in hemorrhoidectomy cases. Majority of the patients were 20–25 years of age with body weight between 61 and 70 kg. Distribution of Prakriti was observed to be highest in Vata-Pitta Prakriti (36.6%). A significant difference was observed in the wipeout period among Prakriti where the duration of wipeout period was more in the Kapha Prakriti individuals (P < 0.0001).

Conclusion:

Kapha involvement increases the wipeout period in posthemorrhoidectomy; however, in Pitta and Vata Prakriti individuals, the wipeout period is less. Future studies could include a larger sample size and various other factors to analyze the involvement of Kapha.

Hemodynamic changes associated with a novel concentration of lidocaine HCl for impacted lower third molar surgery

BACKGROUND

The authors studied the hemodynamic effect influent by using the novel high concentration of lidocaine HCl for surgical removal impacted lower third molar. The objective of this study was to evaluate the hemodynamic change when using different concentrations of lidocaine in impacted lower third molar surgery.

METHODS

Split mouth single blind study comprising 31 healthy patients with a mean age of 23 years (range 19-33 years). Subjects had symmetrically impacted lower third molars as observed on panoramic radiograph. Each participant required 2 surgical interventions by the same surgeon with a 3-week washout period washout period. The participants were alternately assigned one of two types of local anesthetic (left or right) for the first surgery, then the other type of anesthetic for the second surgery. One solution was 4% lidocaine with 1:100,000 epinephrine and the other was 2% lidocaine with 1:100,000 epinephrine. A standard IANB with 1.8 ml volume was used. Any requirement for additional anesthetic and patient pain intra-operation was recorded. Post-operatively, patient was instructed to fill in the patient report form for any adverse effect and local anesthetic preference in terms of intra-operative pain. This form was collected at the seven day follow up appointment.

RESULTS

In the 4% lidocaine group, the heart rate increased during the first minute post-injection (P < 0.05). However, there was no significant change in arterial blood pressure during the operation. In the 2% lidocaine group, there was a significant increase in arterial blood pressure and heart rate in the first minute following injection for every procedure. When the hemodynamic changes in each group were compared, the 4% lidocaine group had significantly lower arterial blood pressure compared to the 2% lidocaine group following injection. Post-operatively, no adverse effects were observed by the operator and patient in either local anesthetic group. Patients reported less pain intra-operation in the 4% lidocaine group compared with the 2% lidocaine group (P < .05).

CONCLUSIONS

Our results suggest that a 4% concentration of lidocaine HCl with 1:100,000 epinephrine has better clinical efficacy than 2% lidocaine HCl with 1:100,000 epinephrine when used for surgical extraction of lower third molars. Neither drug had any clinical adverse effects.

The efficacy of an elevated concentration of lidocaine HCl in impacted lower third molar surgery

Background

There have been few studies on the effect of an elevated concentration of lidocaine hydrochloride in the surgical removal of an impacted lower third molar. This study aimed to examine the efficacy of 4% lidocaine along with 1:100,000 epinephrine compared to 2% lidocaine along with 1:100,000 epinephrine as inferior alveolar nerve block for the removal of an impacted lower third molar.

Methods

This single-blind study involved 31 healthy patients (mean age: 23 y; range: 19-33 y) with symmetrically impacted lower third molars as observed on panoramic radiographs. Volunteers required 2 surgical interventions by the same surgeon with a 3-week washout period. The volunteers were assigned either 4% lidocaine with 1:100,000 epinephrine or 2% lidocaine with 1:100,000 epinephrine as local anesthetic during each operation.

Results

We recorded the time of administration, need for additional anesthetic administration, total volume of anesthetic used. We found that the patient's preference for either of the 2 types of local anesthetic were significantly different (P < 0.05). However, the extent of pulpal anesthesia, surgical duration, and duration of soft tissue anesthesia were not significantly different.

Conclusions

Our study suggested that inferior alveolar nerve block using 4% lidocaine HCl with 1:100,000 epinephrine as a local anesthetic was clinically more effective than that using 2% lidocaine HCl with 1:100,000 epinephrine; the surgical duration was not affected, and no clinically adverse effects were encountered.

What the phlebologist should know about local anesthetics

An increasing number of phlebological interventions are performed under local and tumescent anesthesia. Although the modern local anesthetic agents are generally perceived as being effective and safe drugs, the administration of these drugs may be associated with a number of adverse events. It is therefore mandatory that everyone who uses these compounds has insight into the pharmacological actions of these drugs and is capable of recognizing and adequately treating potential adverse events. The present narrative review summarizes the current knowledge on mechanisms of action of the most important local anesthetic drugs and reviews the potential adverse effects as well as their treatment.

Transient neurologic symptoms (TNS) following spinal anaesthesia with lidocaine versus other local anaesthetics

BACKGROUND

Spinal anaesthesia has been in use since 1898. During the last decade there has been an increase in the number of reports implicating lidocaine as a possible cause of temporary and permanent neurologic complications after spinal anaesthesia. Follow up of patients who received uncomplicated spinal anaesthesia revealed that some of them developed pain in the lower extremities after an initial full recovery. This painful condition that occurs in the immediate postoperative period was named 'transient neurologic symptoms' (TNS).

OBJECTIVES

To study the frequency of TNS and neurologic complications after spinal anaesthesia with lidocaine compared to other local anaesthetics.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials Register (CENTRAL) (The Cochrane Library, Issue 4, 2008); MEDLINE (1966 to August 2008); EMBASE (1980 to week 35, 2008); LILACS (August 2008); and handsearched the reference lists of trials and review articles.

SELECTION CRITERIA

We included all randomized and quasi-randomized studies comparing the frequency of TNS and neurologic complications after spinal anaesthesia with lidocaine as compared to other local anaesthetics.

DATA COLLECTION AND ANALYSIS

Two authors independently evaluated the quality of the relevant studies and extracted the data from the included studies.

MAIN RESULTS

Sixteen trials reporting on 1467 patients, 125 of whom developed TNS, were included in the analysis. The use of lidocaine for spinal anaesthesia increased the risk of developing TNS. There was no evidence that this painful condition was associated with any neurologic pathology; the symptoms disappeared spontaneously by the fifth postoperative day. The relative risk (RR) for developing TNS after spinal anaesthesia with lidocaine as compared to other local anaesthetics (bupivacaine, prilocaine, procaine, levobupivacaine, ropivacaine, and 2-chloroprocaine) was 7.31 (95% confidence interval (CI) 4.16 to 12.86). Mepivacaine was found to give similar results as lidocaine and was therefor omitted from the overall comparison to diminish the heterogeneity.

AUTHORS' CONCLUSIONS

The risk of developing TNS after spinal anaesthesia with lidocaine was significantly higher than when bupivacaine, prilocaine, or procaine were used. The term 'transient neurological symptoms' implies neurologic pathology. Failing identification of the pathogenesis of TNS, consideration should be given to choosing a neutral descriptive term which does not imply a particular causation. One study about the impact of TNS on patient satisfaction and functional impairment demonstrated that non-TNS patients were more satisfied and had less functional impairment after surgery than TNS patients, but this did not influence their willingness to recommend spinal anaesthesia.

Hyperbaric articaine for day-case spinal anaesthesia

BACKGROUND

Articaine and lidocaine are clinically very similar suggesting that articaine could be suitable for day-case spinal anaesthesia. A dose-response study with articaine in ambulatory spinal anaesthesia was therefore performed.

METHODS

In this randomized double-blind study, 90 day-case surgery patients received spinal anaesthesia with 60 mg (A60), 84 mg (A84) or 108 mg (A108) of hyperbaric articaine hydrochloride. Sensory block was tested with pinprick and motor block on a modified Bromage scale. A structured interview was performed on the first and seventh postoperative days.

RESULTS

Sensory block reached the T10 dermatome in a median (range) of 5 (5-10) and was maintained at this level for 70 (35-145), 70 (15-115) and 85 (20-115) min in the A60, A84 and A108 groups, respectively. Six patients in the A108 group, two in the A84 group and one in the A60 group had maximum spread of analgesia to T(1) or higher (NS). Patients in the A108 group needed more medication for hypotension (P=0.018), had more often nausea and vomiting (P=0.027), took oral fluids later (P=0.031) and both sensory block recovery [median (range)] [2.5 (2-4.5) h] (P=0.017) and motor block recovery [2 (1.3-4) h] (P=0.009) were delayed. No patients in the A108 group needed opioid intraoperatively while fentanyl was needed in 5 (17%) and 2 (7%) patients in the A60 and A84 groups, respectively. Discharge criteria were attained in approximately 4.5 h after articaine injection (NS) and no drug-related sequelae were observed.

CONCLUSIONS

Hyperbaric articaine 60 and 84 mg resulted in spinal anaesthesia allowing surgery of the lower extremities for about 1 h. Recovery was rapid. Use of 108 mg of articaine is not recommended because of frequent extensive cephalad spread of the block, accompanied by arterial hypotension and nausea.

Transient neurologic symptoms (TNS) following spinal anaesthesia with lidocaine versus other local anaesthetics

BACKGROUND

Spinal anaesthesia has been in use since the turn of the late nineteenth century. During the last decade there has been an increase in the number of reports implicating lidocaine as a possible cause of temporary and permanent neurologic complications after spinal anaesthesia. Follow-up of patients who received uncomplicated spinal anaesthesia revealed that some of them developed pain in the lower extremities after an initial full recovery. This painful condition that occurs in the immediate postoperative period was named "transient neurologic symptoms" (TNS).

OBJECTIVES

To study the frequency of TNS and neurologic complications after spinal anaesthesia with lidocaine, compared to other local anaesthetics.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (CENTRAL), (The Cochrane Library, Issue 1, 2005); MEDLINE (1966 to January 2005); EMBASE (1980 to week 6, 2005); LILACS (March 2005); and handsearched the reference lists of trials and review articles.

SELECTION CRITERIA

We included all randomized and pseudo-randomized studies comparing the frequency of TNS and of neurologic complications after spinal anaesthesia with lidocaine as compared to other local anaesthetics.

DATA COLLECTION AND ANALYSIS

Two authors independently evaluated the quality of the relevant studies and extracted the data from the included studies.

MAIN RESULTS

Fifteen trials, reporting 1437 patients, 120 of whom developed transient neurologic symptoms, were included in the analysis. The use of lidocaine for spinal anaesthesia increased the risk of developing TNS. There was no evidence that this painful condition was associated with any neurologic pathology; the symptoms disappeared spontaneously by the fifth postoperative day. The relative risk (RR) for developing TNS after spinal anaesthesia with lidocaine as compared to other local anaesthetics (bupivacaine, prilocaine, procaine, levobupivacaine and ropivacaine) was 7.16 (95% confidence interval (CI) 4.02, 12.75).

AUTHORS' CONCLUSIONS

The risk of developing TNS after spinal anaesthesia with lidocaine was significantly higher than when bupivacaine, prilocaine and procaine were used. The term "TNS", which implies a positive neurologic finding, should not be used for this painful condition. One study about the impact of TNS on patient satisfaction and functional impairment demonstrated that non-TNS patients were more satisfied and had less functional impairment after surgery than TNS patients, but this did not influence their willingness to recommend spinal anaesthesia.

The Incidence of Transient Neurologic Symptoms After Spinal Anesthesia with Mepivacaine

We prospectively evaluated 1273 patients who received spinal (or combined spinal-epidural [CSE]) anesthesia with 1.5% mepivacaine (plain, no glucose) for ambulatory surgery. We hypothesized that analysis of a large series of patients would confirm previous findings that isobaric 1.5% mepivacaine is not frequently associated with transient neurologic symptoms (TNS). Patients were contacted twice after the anesthetic, at days 1-4 and days 6-9. One-thousand-two-hundred-ten patients were successfully contacted postoperatively (95% follow-up rate). None of the patients had permanent neurologic sequelae from the anesthetic. None of the 372 CSE anesthetics was inadequate for surgery. Fourteen of 838 (1.7%) of the spinal anesthetics were inadequate. TNS, defined as the new onset of back pain that radiated bilaterally to buttocks or distally, occurred in 78 patients (6.4%; 95% confidence intervals 5.1%-8%). The mean age of patients who developed TNS (48 +/- 14 yr) was older than that of patients without TNS (41 +/- 16 yr) (P < 0.001). TNS was not influenced by gender or intraoperative position. The frequent success rate and infrequent rates of complications such as TNS and postdural puncture headache suggest that spinal anesthesia with mepivacaine is likely to be a safe and effective anesthetic for ambulatory patients.

A randomized controlled trial to measure the effectiveness of a sacral wedge in preventing postoperative back pain following trans-urethral resection of the prostate (TURP) in lithotomy position

BACKGROUND

Postoperative back pain is a common, yet under reported, complication of surgery. Previous studies, although small in number, have indicated that the use of a sacral wedge is effective in reducing the incidence of postoperative back pain.

AIM

The aim of the study was to test the hypothesis that the intra-operative use of a sacral wedge would decrease the incidence of postoperative back pain in patients undergoing trans-urethral resection of the prostate in lithotomy position.

METHODS

The design of the study was a randomized controlled trial involving the use of a sacral wedge intra-operatively in a male population undergoing trans-urethral resection of the prostate. A total of 236 participants was recruited to the study and allocated to the control or intervention group by block randomization. All patients selected one of three different sized sacral wedges for use during surgery. Data were collected preoperatively, intra-operatively and at postoperative days 2 and 4 and the tools included a structured questionnaire, Oswestry Disability Questionnaire, a visual analogue scale to measure pain intensity and a body map to record its location.

RESULTS

Fifty-two per cent of participants reported having a history of back pain and point prevalence on admission to hospital was 27%. Twenty-eight per cent of participants experienced back pain on day 2 postoperatively and this decreased to 14% on day 4. There was no significant difference between the control and intervention groups. The severity of back pain increased after surgery. Postoperatively there were reports of back pain from participants who had not reported a history of back pain before their admission for surgery.

CONCLUSIONS

In contrast to other studies we found no evidence to support the use of a sacral wedge intra-operatively to reduce the incidence of postoperative back pain.

RELEVANCE TO CLINICAL PRACTICE

Despite the non-significant results, the high level of postoperative back pain stills draws attention to the need to develop strategies to reduce its incidence.

Transient neurological syndrome: does it really exist?

PURPOSE OF REVIEW

Subarachnoid injection of local anesthetics has been related to the appearance of transient neurological symptoms (called transient neurologic syndrome), as reflected by a number of clinical reports showing their incidence in clinical practice. However, the etiology of this syndrome is virtually unknown, as is the number of factors implicated in its development. This review will attempt to clarify this entity and its relationship with spinal anesthesia.

RECENT FINDINGS

Intrathecal administration of local anesthetics is known to increase glutamate concentration in cerebrospinal fluid and histopathologic changes of motor neurons in the lumbar spinal cord, suggesting damage of dorsal and ventral roots. In-vitro studies of cultured neurons exposed to different concentrations of local anesthetics have shown changes in growth of cones and neurites, which may be related to transient neurologic syndrome.

SUMMARY

The latest studies show biochemical and anatomopathologic changes that support the structural basis of the existence of transient neurologic syndrome. In the authors' view, transient neurologic syndrome could represent the lower end of a spectrum of local anesthetic toxicity. Recent findings demonstrate that nerve membrane damage induced by highly concentrated local anesthetics such as lidocaine, tetracaine, dibucaine and procaine may generate irreversible neural injury. Still further studies are needed to establish the relationship between morphological changes induced in vitro and the occurrence of clinical symptoms.

Neurotoxicity of intrathecal local anaesthetics and transient neurological symptoms

Local anaesthetics have been placed in the intrathecal space for approximately 100 years. Currently used intrathecal local anaesthetics appear to be relatively benign on the basis of the low incidence of permanent neurological deficits. In large retrospective surveys of 4000-10 000 patients, the incidence of persistent neurological sequelae after subarachnoid anaesthesia varies between 0.01 and 0.7%. Since its introduction in 1948, hyperbaric 5% lidocaine has been used for millions of spinal anaesthetics. The predictable onset and limited duration of action have made lidocaine one of the most popular spinal anaesthetics currently available. Concern about the use of spinal lidocaine began in 1991 with published reports of cauda equina syndrome after continuous spinal anaesthesia. In 1993, Schneider published a case report of four patients undergoing spinal anaesthesia who postoperatively experienced aching and pain in the buttocks and lower extremities. This chapter reviews the neurotoxicity of spinal local anaesthetics, as well as the incidence, possible aetiology, and treatment of transient neurological symptoms after lidocaine spinal anaesthesia.

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.

Spinal anaesthesia: local anaesthetics and adjuncts in the ambulatory setting

Intrathecal lidocaine remains a popular choice for ambulatory spinal anaesthesia due to its reliability, rapid onset and predictable rapid recovery profile. However, concerns with transient neurological symptoms (TNS) and their significant association with lidocaine have generated interest in alternative local anaesthetic agents to provide adequate spinal anaesthesia with the briefest possible recovery period. This chapter updates current data on drug dose-response relationships for local anaesthetics and the increasing use of intrathecal adjuncts to improve the anaesthetic and recovery profile for ambulatory spinal anaesthesia. Newer spinal anaesthetic techniques for common ambulatory procedures highlight the success of combining subclinical doses of local anaesthetics and intrathecal adjuncts. Controversies regarding the possible lower risk of TNS with newer spinal anaesthetic techniques and new discharge criteria are reviewed. The final section provides technical pearls to optimize ambulatory spinal anaesthetic outcomes.

Practical pediatric regional anesthesia

In children, regional anesthetic techniques are safe and effective adjuncts to general anesthesia and for postoperative pain relief. Application of the techniques described in this article will contribute to improved care for pediatric patients undergoing surgical procedures. The judicious choice of local anesthetics, along with the blockades of targeted nerves, decrease the need for supplemental analgesics in the recovery phase.

Postoperative pain control using epidural catheters after anterior spinal fusion for adolescent scoliosis

STUDY DESIGN

A prospective review of patients undergoing epidural catheter placement after anterior spinal fusion and instrumentation for adolescent scoliosis was performed. Data were collected using visual analog pain scores reflecting the patients' perception of their pain control.

OBJECTIVES

To present the authors' technique for epidural catheter placement and dosing protocol, and to demonstrate the results from postoperative pain control after anterior spinal instrumented fusion for 10 consecutive patients.

SUMMARY OF BACKGROUND DATA

The literature regarding the benefits of epidural catheters after spinal surgery is contradictory, even with controlled studies comparing epidural catheters with intravenous morphine patient-controlled anesthesia. The authors believe that this lack of consensus stems from varied epidural dosing protocols and techniques in catheter placement, which they have witnessed anecdotally at their own institution. This prompted the authors to develop and refine a standardized dosing and catheter placement protocol for pain control after spinal surgery.

METHODS

Epidural catheters were placed intraoperatively before wound closure, then removed on postoperative Day 5. Dosing consisted of fentanyl (1 microg/kg) and hydromorphone (5 microg/kg) diluted in preservative-free saline (0.2 mL/kg). After surgery, dosing consisted of 0.1% ropivacaine and hydromorphone (10 microg/ml) continuously infused at 0.2 mL/kg/hour. Postoperative pain control was assessed on each postoperative day using a visual analog pain scale with choices ranging from 0 to 10.

RESULTS

The arithmetic mean of the median pain scores after surgery was 2.1. The mean of the maximum pain scores for the 5 days was 4.1. Three patients required an epidural bolus and a 20% increase in the epidural infusion rate. One patient was judged to be excessively sleepy, so the epidural infusion rate was decreased by 20%. Pruritus requiring diphenhydramine developed in three patients. No other adverse effects related to epidural analgesia were noted. No catheters were accidentally pulled out or disconnected.

CONCLUSION

By following the dosing protocol described, epidural catheters can be used safely and effectively to control postoperative pain after anterior instrumentation and spinal fusion for adolescent scoliosis.

Transient neurologic symptoms after spinal anaesthesia using isobaric 2% mepivacaine and isobaric 2% lidocaine

BACKGROUND

Transient Neurological Symptoms (TNS) syndrome following subarachnoid anaesthesia was initially associated with hyperbaric lidocaine 50 mg/ml, but has also been reported with most local anaesthetics, including hyperbaric mepivacaine 40 mg/ml. The aim of this study was to determine the incidence of TNS after subarachnoid anaesthesia using isobaric mepivacaine 20 mg/ml and isobaric lidocaine 20 mg/ml.

METHODS

Eighty patients of both sexes, ASA class I-II, scheduled for elective minor orthopaedic surgery under subarachnoid anaesthesia, were prospectively included and randomly allocated to receive 40-60 mg of either isobaric mepivacaine 20 mg/ml (Group M) or isobaric lidocaine 20 mg/ml (Group L). Patients were evaluated on the first postoperative day by one investigator unaware of the grouping, looking for symptoms suggestive of TNS, such as pain or dysaesthesias in the buttocks or lower limbs with or without back pain.

RESULTS

TNS symptoms were observed in three patients (7.5%) of Group M and in one patient (2.5%) of Group L, without statistically significant differences between the groups. Symptoms had an abrupt onset and relief, lasted from 45 min to 24 h, and had a complete resolution without sequelae. The only statistically significant difference between groups was longer motor blockade in Group M (P=0.0031).

CONCLUSION

In this study TNS was associated with isobaric mepivacaine 20 mg/ml, with an incidence of 7.5%, and with isobaric lidocaine 20 mg/ml, with an incidence of 2.5%, in patients having orthopaedic procedures in the supine position.

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.

The incidence of transient neurological symptoms after spinal anaesthesia with lidocaine compared to prilocaine

The purpose of this double-blind study was to investigate the incidence of transient neurological symptoms after the use of isobaric lidocaine and isobaric prilocaine for spinal anaesthesia. Seventy patients (ASA 1-2, age between 18 and 70 years) were randomly assigned to two groups of 35 patients each, to receive either isobaric 2% lidocaine 4 ml or isobaric 2% prilocaine 4 ml intrathecally, at the L3-4 interspace. One patient in the prilocaine group could not be included because data were incomplete. On the first postoperative day, patients were evaluated for transient neurological symptoms. Pain was scored on a 10-point scale. Seven patients (20%) in the lidocaine group had transient neurological symptoms with a mean pain score of 5.3, whereas no patient in the prilocaine group had these complaints (p = 0.006). Symptoms disappeared within 4 days. Prilocaine results in a lower incidence of transient neurological symptoms than lidocaine intrathecally and therefore it is more suitable for short surgical procedures.

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.

Toxicity of spinal local anaesthetics

Recent reports of severe neurological injury after spinal anaesthesia have generated concerns about the neurotoxic potential of local anaesthetics and, in particular, of lignocaine. Further, there is an increasing body of evidence indicating that transient neurological symptoms commonly occur after uneventful lignocaine spinal anaesthesia but not after bupivacaine. Results from an epidemiological study suggest that patient positioning and outpatient status are major co-factors. Neither the dose nor the concentration of lignocaine appear to reduce the risk for transient neurological symptoms. Available data on alternative short-acting local anaesthetics with respect to transient neurological symptoms are limited and conflicting. Experimental data provide further information on factors contributing to local anaesthetic induced neurotoxicity: adrenaline significantly increases the neurotoxic effects of lignocaine in vivo, whereas the addition of glucose does not.