Long-Term Neurological Complications Associated with Surgery and Peripheral Nerve Blockade: Outcomes after 1065 Consecutive Blocks

Pain Management and Opioid Use with Long-Acting Peripheral Nerve Blocks for Hand Surgery: A Descriptive Study

Background

Peripheral nerve blocks (PNBs) are used in multiple surgical fields to provide a high level of regional pain relief with a favorable adverse effect profile. Peripheral nerve blocks aim to decrease overall perioperative pain and lower systemic analgesic requirements. Short-acting anesthetic agents are commonly given as single-injection PNBs for pain relief, typically lasting less than 24 hours. Liposomal bupivacaine is a newer anesthetic formulation lasting up to 72 hours as a single-injection PNB and may allow patients to recover postoperatively with a lower need for opioid analgesics.

Objectives

This study investigates peri- and postoperative pain and opioid use in patients receiving a long-acting brachial plexus PNB for hand surgery.

Methods

A retrospective review of patients who underwent a long-acting PNB using liposomal bupivacaine in the brachial plexus for minor hand operations was performed between July 2020 and May 2023 in Florida, USA. Patients were administered a ten-question survey regarding perioperative pain levels, post-operative symptoms, patient satisfaction, postoperative opioid use, and postoperative non-opioid analgesics.

Results

One hundred three patients, including 21 males and 82 females with an average age of 68.3 ± 15.8 years, completed a survey (34.2% response rate). Patients reported a considerable reduction in pain from 7.9 ± 2.2 out of ten before the PNB to 1.6 ± 1.8 in the perioperative period, 4.3 ± 2.7 in postoperative days zero to three, and 3.8 ± 2.4 in postoperative days four and five. Nerve block effects lasted a mean of 2.2 ± 2.0 days and patients reported a high level of satisfaction regarding their pain management plan with a score of 9.4 ± 1.4 out of ten. 20.4% of patients were prescribed opioids and 41.7% used NSAIDs postoperatively.

Conclusions

Liposomal bupivacaine PNBs effectively reduced peri- and postoperative pain with pain relief lasting 2.2 ± 2.0 days. Patients were highly satisfied with their pain management and there was a low rate of postoperative opioid prescription. Given these results, long-acting PNBs have the potential to significantly improve patient satisfaction, reduce anesthesia use, and reduce postoperative opioid prescription.

Multimodal Approach in Minimizing Transient Neurological Complications Following Single Shot Brachial Plexus Block: A Prospective Observational Study

PURPOSE

The aim of the study was to assess the benefit of a using multimodal approach, including injection pressure monitoring (IPM) and different techniques of nerve localization, with respect to complications following single-shot brachial plexus block (SSBPB).

METHODS

In this study, 238 adults (132 males and 106 females) undergoing upper-limb surgeries under peripheral nerve block (PNB) were evaluated. Of these, 198 patients were given supraclavicular block, and 40 patients received interscalene block using either ultrasound (USG) and peripheral nerve stimulation (PNS) or PNS alone. Injection pressure monitoring was used in 216 patients.

RESULTS

Transient neurological deficit (TND) was observed in six out of 198 patients where USG and NS were used along with IPM as opposed to 12 out of 18 patients without IPM (p<0.0001). In patients where only PNS was used, transient neurological deficit (TND) was seen in six out of 18 patients with IPM as opposed to all the patients (n=4) without IPM (p<0.02). Among the patients where injection pressure was monitored, six out of 198 patients developed TND when both USG and NS were used, compared to six out of 18 patients where only PNS was used (p<0.007).

CONCLUSION

Use of injection pressure monitoring along with different nerve localization techniques results in fewer transient neurological deficits.

Local Anesthetic-Induced Central Nervous System Toxicity during Interscalene Brachial Plexus Block: A Case Series Study of Three Patients

Local anesthetics are commonly administered by nuchal infiltration to provide a temporary interscalene brachial plexus block (ISB) in a surgical setting. Although less commonly reported, local anesthetics can induce central nervous system toxicity. In this case study, we present three patients with acute central nervous system toxicity induced by local anesthetics applied during ISB with emphasis on neurological symptoms, key neuroradiological findings and functional outcome. Medical history, clinical and imaging findings, and outcome of three patients with local anesthetic-induced toxic left hemisphere syndrome during left ISB were analyzed. All patients were admitted to our neurological intensive care unit between November 2016 and September 2019. All three patients presented in poor clinical condition with impaired consciousness and left hemisphere syndrome. Electroencephalography revealed slow wave activity in the affected hemisphere of all patients. Seizure activity with progression to status epilepticus was observed in one patient. In two out of three patients, cortical FLAIR hyperintensities and restricted diffusion in the territory of the left internal carotid artery were observed in magnetic resonance imaging. Assessment of neurological severity scores revealed spontaneous partial reversibility of neurological symptoms. Local anesthetic-induced CNS toxicity during ISB can lead to severe neurological impairment and anatomically variable cerebral lesions.

Combination Preemptive Peripheral Nerve Block in Limb Surgery. A Prospective Study

Background and objectives: Patients often suffer from moderate to severe pain during the early recovery period in orthopedic surgery. We investigated the impact of a single-shot preoperative peripheral nerve block (PNB) on post-anesthesia recovery parameters and interleukin (IL)-6 level during limb surgery. Materials and Methods: A prospective randomized controlled study was conducted, and patients scheduled for limb surgery were recruited. Sixty patients were randomly assigned to either the PNB group or control group, who received morphine as a primary analgesic. The peak verbal numeric rating scale (NRS) score in the post-anesthesia care unit (PACU) was evaluated as a primary outcome. We also recorded rescue analgesics requirement and wake-up time from anesthesia in the PACU. In addition, the change of plasma IL-6 level after incision was measured. Results: Fifty-two patients completed the study, 27 and 25 cases in the PNB and control group, respectively. Preemptive PNB significantly reduced peak NRS score in the PACU compared to control group. Lower rescue analgesics requirement and rapid wake-up from anesthesia were also noted in PNB group. The IL-6 concentration increased less in the PNB group at 2 h after incision. Conclusions: Preemptive PNB attenuates IL-6 expression 2 h after incision and improves pain management in the PACU. PNB was considered as an essential part of pain management in limb surgery.

Regional Nerve Block Complication Analysis Following Peripheral Nerve Block During Foot and Ankle Surgical Procedures

Background

Foot and ankle surgeries are frequently accompanied by a peripheral nerve block in order to reduce postoperative pain. Higher than expected complication rates with peripheral nerve blocks have led to increased concern among surgeons and patients. To our knowledge, no study conducted by the treating surgeon has identified risk factors that may predispose a patient to complications. Our goal was to attempt to identify those risk factors.

Methods

We reviewed patient charts of those who underwent an orthopedic foot and ankle procedure between 2013 and 2018, as performed by the senior author. This yielded 992 procedures performed across four surgical locations. Of these procedures, 137 procedures were removed because no block was used. The remaining cases were analyzed for nerve complications, defined as sensory or motor deficits along the distribution of a nerve. The patients were divided into those with and without complications and were evaluated for differences. Statistical analysis was performed using the SAS^® software (SAS Institute Inc., Cary, North Carolina, USA).

Results

The overall short-term complication rate was 10.1% and the long-term complication rate was 4.3%, with a total of 855 blocks given. Electromyographies (EMGs) were performed on 24.4% of the patients with a complication. Of the EMGs, 95.2% confirmed nerve complications in the distribution of the blocked nerve. The significant factors associated with complications were age, BMI, location, and smoking status. A regression analysis was performed to determine the odds ratio for individual factors. Those with significantly higher odds ratio were between 40 and 65 years of age, had normal or underweight BMI, underwent surgery at an outpatient surgery center, and were current smokers.

Conclusions

Our study suggests that there are significant epidemiological factors in predicting postoperative complications related to a peripheral nerve block. The study also shows a similar short-term complication rate but a higher long-term complication rate than other studies. This data are important because it allows for an informed decision to be made between a surgeon, anesthesiologist, and the patient regarding the safety and necessity of delivering a preoperative peripheral nerve block based on patient risk factors.

Peripheral nerve blocks of the pelvic limb in dogs: A retrospective clinical study

Objective: To evaluate the success rate and complications of lumbar plexus (LP) and femoral nerve (FN) blocks, each combined with a sciatic nerve (SN) block, in dogs undergoing pelvic limb orthopaedic surgery.

Design: Retrospective clinical study.

Procedure: The intra-operative and postoperative clinical records of dogs that underwent orthopaedic surgery of the pelvic limb were reviewed. Dogs were divided into two groups according to the analgesic technique used during surgery: dogs that received a peripheral nerve block (group PNB) and dogs in which opioid analgesia alone was used (group C).

Results: The PNB and C groups included 265 and 31 dogs, respectively. Complete statistical analysis was performed in 115/265 dogs of PNB group. The overall success rate of the PNB performed was 77% (89/115): 76% (72/95) and 85% (17/20) for LP-SN and FN-SN blocks, respectively. In group PNB, the prevalence of intra-operative hypotension was 7.8% (9/115). Only one (out of 95 [1.05%]) LP-SN block manifested transient postoperative bilateral pelvic limb paralysis. None of the 265 dogs in group PNB manifested neurological complications at six weeks postoperatively.

Conclusion: The success rate and the absence of neurological complications obtained support the use of LP-SN and FN-SN for loco-regional anaesthesia and analgesia in dogs undergoing orthopaedic surgery of the pelvic limb.

AnAnkle Trial study protocol: a randomised trial comparing pain profiles after peripheral nerve block or spinal anaesthesia for ankle fracture surgery

INTRODUCTION

Ankle fracture surgery is a common procedure, but the influence of anaesthesia choice on postoperative pain and quality of recovery is poorly understood. Some authors suggest a benefit of peripheral nerve block (PNB) in elective procedures, but the different pain profile following acute fracture surgery and the rebound pain on cessation of the PNB both remain unexplored. We present an ongoing randomised study aiming to compare primary PNB anaesthesia with spinal anaesthesia for ankle fracture surgery regarding postoperative pain profiles and quality of recovery.

METHODS AND ANALYSIS

AnAnkle Trial is a randomised, dual-centre, open-label, blinded analysis trial of 150 adult patients undergoing primary internal fixation of an ankle fracture. Main exclusion criteria are habitual opioid use, impaired pain sensation, other painful injuries or cognitive impairment. The intervention is ultrasound-guided popliteal sciatic (20 mL) and saphenal nerve (8 mL) PNB with ropivacaine 7.5 mg/mL, and controls receive spinal anaesthesia (2 mL) with hyperbaric bupivacaine 5 mg/mL. Postoperatively all receive paracetamol, ibuprofen and patient-controlled intravenous morphine on demand. Morphine consumption and pain scores are registered in the first 27 hours and reported as an integrated pain score as the primary endpoint. Pain score intervals are 3 hours and we will use the area under curve to get a longitudinal measure of pain. Secondary outcomes include rebound pain on cessation of anaesthesia, opioid side effects (Opioid-Related Symptom Distress Scale), quality of recovery (Danish Quality of Recovery-15 score) and pain scores and medication days 1-7 (diary).

ETHICS AND DISSEMINATION

The study has been approved by the Regional Ethics Committees in the Capital Region of Denmark, the Danish Data Protection Agency and the Danish Health and Medical Authority. We will publish the results in international peer-reviewed medical journals.

TRIAL REGISTRATION NUMBER

AnAnkle Trial is registered in the European Clinical Trials Database (EudraCT 2015-001108-76).

Retrospective assessment of peripheral nerve block techniques used in cats undergoing hindlimb orthopaedic surgery

OBJECTIVES

The aim of this study was to assess retrospectively the efficacy and complication rate of hindlimb peripheral nerve blocks (PNBs) in cats.

METHODS

Clinical records of cats that received PNBs and underwent hindlimb orthopaedic surgery from February 2010 to October 2014 were examined. Type of PNB, type and dose of local anaesthetic used, end-expiratory fraction of isoflurane (FE'Iso) administered, additional intraoperative analgesia, incidence of hypotension, postoperative opioid requirement, postoperative contralateral limb paralysis and neurological complications at the 6 week re-examination were investigated.

RESULTS

Eighty-nine records were retrieved but only 69 were analysed. Four combinations of PNBs were used: 34 lateral preiliac (LPI) approach to lumbar plexus (LP) associated with lumbar paravertebral approach to sciatic nerve (SN); 20 LPI-LP associated with the lateral approach to SN; three LPI-LP associated with gluteal approach to SN; 12 dorsal-paravertebral (DPV) approach to LP associated with lateral SN. Levobupivacaine was used for the majority of PNBs. The mean intraoperative FE'Iso was 1.15%; hypotension was documented in 55.1% of anaesthetics, while 31.8% of cats received fentanyl and/or ketamine intraoperatively. Postoperatively, 72.7% of cats received at least one dose of opioid, while five cats required further postoperative analgesia (ketamine constant rate infusion and/or gabapentin). No cats showed contralateral limb paralysis and neurological complications at the 6 week re-examination. No differences were found when comparing the different PNBs used.

CONCLUSIONS AND RELEVANCE

PNBs contributed to perioperative anaesthesia/analgesia in cats undergoing hindlimb orthopaedic surgery. However, the clinical relevance of intraoperative hypotension needs further investigation.

In-plane three-step needle insertion technique for ultrasound-guided continuous femoral nerve block after total knee arthroplasty: a retrospective review of 488 cases

BACKGROUND

Continuous femoral nerve block (CFNB) improves postoperative analgesia after total knee arthroplasty (TKA). The aim of this study was to investigate the clinical efficacy and complications of our in-plane three-step needle insertion technique that was devised to reduce the risk of direct femoral nerve injury during CFNB in anesthetized patients.

METHODS

This retrospective study included 488 patients who had undergone TKA. Ultrasound (US)-guided CFNB was performed under general or spinal anesthesia using an in-plane, three-step needle insertion technique. The success rate and difficulties of catheter placement, clinical efficacy of analgesia, and complications were recorded.

RESULTS

Femoral catheters were placed with a 100% success rate. In 488 patients, real-time US imaging revealed easy separation of the fascia iliaca and the femoral nerve following injection of local anesthetic through a Tuohy needle. Verbal numerical rating scale pain scores (0-10) were 2.0 ± 1.2, 3.5 ± 1.9, 3.2 ± 1.7, 2.9 ± 1.3, and 2.5 ± 1.1 at 1, 6, 12, 24 and 48 h postoperatively. No femoral hematoma, femoral abscess, or neurologic complications, including paresthesia or neurologic deficits, were observed during the 8-week follow-up period.

CONCLUSIONS

This retrospective study suggests that an in-plane three-step needle insertion technique for CFNB may reduce the risk of femoral nerve injury in anesthetized patients.

Will the Real Benefits of Single-Shot Interscalene Block Please Stand Up? A Systematic Review and Meta-Analysis

BACKGROUND

Interscalene block (ISB) can provide pain relief after shoulder surgery, but a reliable quantification of its analgesic benefits is lacking. This meta-analysis examines the effect of single-shot ISB on analgesic outcomes during the first 48 hours after shoulder surgery.

METHODS

We retrieved randomized and quasirandomized controlled trials examining the analgesic benefits of ISB compared with none in shoulder surgery. Severity of postoperative pain measured on a visual analog scale (10 cm scale, 0 = no pain, 10 = worst pain) at rest at 24 hours was the designated primary outcome. Secondary outcomes included pain severity at rest and with motion at 2, 4, 6, 8, 12, 16, 32, 36, 40, and 48 hours postoperatively. Opioid consumption, postoperative nausea and vomiting, patient satisfaction with pain relief, and postanesthesia care unit and hospital discharge time were also assessed.

RESULTS

A total of 23 randomized controlled trials, including 1090 patients, were analyzed. Patients in the ISB group had more severe postoperative pain at rest by a weighed mean difference (95% confidence interval) of 0.96 cm (0.08-1.83; P = 0.03) at 24 hours compared with no ISB, but there was no difference in pain severity beyond that point. The duration of pain relief at rest and with motion after ISB were 8 and 6 hours, respectively, with a corresponding weighed mean difference in visual analog scale pain scores (99% confidence interval) of -1.59 cm (-2.60 to -0.58) and -2.20 cm (-4.34 to -0.06), respectively, with no additional pain relief benefits beyond these points. ISB reduced postoperative opioid consumption up to 12 hours, decreased postoperative nausea and vomiting at 24 hours, and expedited postanesthesia care unit and hospital discharge. The type, dose, and volume of local anesthetic used did not affect the results.

CONCLUSIONS

ISB can provide effective analgesia up to 6 hours with motion and 8 hours at rest after shoulder surgery, with no demonstrable benefits thereafter. Patients who receive an ISB can suffer rebound pain at 24 hours but later experience similar pain severity compared with those who do not receive an ISB. ISB can also provide an opioid-sparing effect and reduce opioid-related side effects in the first 12 and 24 hours postoperatively, respectively. These findings are useful to inform preoperative risk-benefit discussions regarding ISB for shoulder surgery.

Comparison Between Ultrasonography-Guided Popliteal Sciatic Nerve Block and Spinal Anesthesia for Hallux Valgus Repair

BACKGROUND

We aimed to compare the efficacy, postoperative pain scores, adverse effects, additional analgesic requirements, and patient satisfaction scores of ultrasonography-guided sciatic nerve block by popliteal approach with spinal anesthesia for hallux valgus correction surgery.

METHODS

Sixty patients scheduled for hallux valgus correction surgery were enrolled in this prospective randomized study. Unilateral spinal block was performed on patients in the spinal anesthesia group. Popliteal block group patients received popliteal sciatic nerve block with guidance by both nerve stimulator and ultrasonography. Durations of anesthetic and operative interventions and time until the initiation of surgery were recorded for both groups. Pain magnitude of the patients at the 2nd, 4th, 6th, 12th, and 24th hours following anesthetic interventions were assessed with a visual analog scale (VAS). Adverse effects such as postoperative urinary retention and postdural puncture headache were recorded. Also, patient satisfaction was recorded. Patients were interviewed by phone for anesthetic and operative complications at 72 hours postoperatively.

RESULTS

Spinal anesthesia group patients exhibited hypotension, bradycardia, postdural puncture headache, and urinary retention rates of 6.6%, 3.3%, 10%, and 3.3%, respectively. Popliteal block group patients showed none of these adverse effects. Moreover, VAS scores of the patients at the 2nd, 4th, 6th, and 12th hours were significantly lower (P < .001, P = .003, P < .001, P <.001, respectively), postoperative first analgesic requirement times were significantly longer (P < .001), and pain satisfaction scores were significantly higher (P < .001) in the popliteal block group.

CONCLUSION

Given the complications related to spinal anesthesia and its insufficiency to maintain analgesia postoperatively, we believe the preferred anesthetic method should be peripheral nerve blocks for hallux valgus correction surgeries.

LEVEL OF EVIDENCE

Level I, randomized prospective study.

Multimodal Analgesia for Total Joint Arthroplasty

Optimal perioperative pain control for total joint arthroplasty remains a challenge. Whereas traditional regimens have relied heavily on opioids, newer multimodal pathways are increasingly gaining popularity as safer and more effective alternatives. The main premise of multimodal analgesia is decreased consumption of opioids, and hence lesser opioid-related adverse events. Other reported advantages include lower pain scores, faster functional recovery, higher patient satisfaction, and shorter length of hospital stay. Unfortunately, despite the advent of numerous analgesic techniques, the multimodal approach has remained widely variable, making direct comparison between studies difficult to interpret. This article provides an extensive review of traditional and modern perioperative interventions in pain management for total joint arthroplasty, including intravenous patient-controlled analgesia, epidural infusion, oral opioids, nonsteroidal anti-inflammatory drugs, acetaminophen, peripheral nerve blocks, periarticular infiltration, steroids, anticonvulsants, and long-acting local anesthetics. Emphasis is placed on pathophysiology, clinical evidence, and timing. A standardized multimodal analgesia protocol is also proposed based on best available evidence. In addition to pharmacologic interventions, patient education and interdisciplinary collaboration among the care teams play an important role in the success of any treatment pathway. With a growing demand for total joint arthroplasty in an era of bundled payments and accountable care, there has never been a greater need for a standardized multimodal analgesia pathway.

Duration of upper and lower extremity peripheral nerve blockade is prolonged with dexamethasone when added to ropivacaine: a retrospective database analysis

BACKGROUND

Dexamethasone, when added to local anesthetics, has been shown to prolong the duration of peripheral nerve blocks; however, there are limited studies utilizing large numbers of patients. The purpose of this study was to examine the effect of adding dexamethasone to ropivacaine on duration of nerve blocks of the upper and lower extremity.

METHODS

We reviewed 1,040 patient records collected in an orthopedic outpatient surgery center that had received an upper or lower extremity peripheral nerve block with ropivacaine 0.5% with or without dexamethasone and/or epinephrine. The primary outcome was duration of analgesia in upper or lower extremity blocks containing dexamethasone as an adjunct. Secondary outcomes included postoperative patient pain scores, satisfaction, and the incidence of block related complications. Linear and ordinal logistic regression models were used to examine the independent effect of dexamethasone on outcomes.

RESULTS

Dexamethasone was observed to increase median block duration by 37% (95% confidence interval: 31-43%). The increased block duration persisted within body regions (upper and lower) and across a range of block types. Dexamethasone was also observed to reduce pain scores on the day of surgery (P = 0.001) and postoperative day 1 (P < 0.001). There was no significant difference in duration of nerve blocks when epinephrine (1:400,000) was added to 0.5% ropivacaine with or without dexamethasone.

CONCLUSION

The addition of dexamethasone to 0.5% ropivacaine prolongs the duration of peripheral nerve blocks of both the upper and lower extremity.

Incidence and severity of complications due to femoral nerve blocks performed for knee surgery

BACKGROUND

While single shot femoral nerve blocks and indwelling femoral nerve catheters provide significant peri-operative analgesia, there are small but serious risks of neurovascular complications. We aimed to determine the incidence and characterise the nature of neural complications arising from femoral nerve blocks performed for knee surgery.

METHODS

One thousand eight hundred and two patients receiving a femoral nerve block for knee surgery during the study period were screened. Patients with possible neurological symptoms were evaluated with a detailed physical examination and self-report questionnaires. Also measures of depression, anxiety and tension/stress were collected.

RESULTS

In the patients screened, an incidence of 1.94% was found. Of the 24 patients available for testing, 4 had bilateral symptoms following bilateral nerve blocks. All had sensory abnormalities in the distribution of the femoral nerve. The incidence was significantly higher in females (females=2.5%, males=0.83% p=0.01) and in patients receiving a single shot block (single shot=2.66%, femoral catheter=0.93, p=0.01).

CONCLUSIONS

The incidence of neurological complication after FNB was higher in this series than typically reported and the symptoms significantly influenced the quality of life in the affected cases. The decision to include a femoral nerve block in the peri-operative analgesic regimen should be made on an individual basis considering the risks and benefits.

Comparative study of ultrasound-guided continuous femoral nerve blockade with continuous epidural analgesia for pain relief following total knee replacement

Background:

Regional analgesia is widely used for total knee replacement surgeries (TKR) as it has lesser side-effects and better analgesic efficacy when compared with traditional oral analgesics. Peripheral nerve blockade has also been utilized, including continuous infusion techniques. With the use of ultrasound, the needle and catheter placement can be done accurately under real-time guidance. This may prove a more suitable approach compared with the epidural technique.

Aims:

Post-operative analgesia in TKR patients was compared between continuous epidural analgesia (CEA) and continuous femoral block (CFB) techniques. VAS scores and use of rescue analgesic were used as parameters. Secondary aims included comparison of rehabilitation scores and side-effects in the form hypotension, vomiting, itching and urinary retention.

Settings and Design:

Randomised, controlled, non-blinded study done in a tertiary care private hospital.

Methods:

Forty-two patients fulfilling the study criteria were randomised into the CEA and CFB groups. In total, four patients: three in the CFB group and one in the CEA group, were excluded because of catheter migration.

Statistical Analysis:

Mean VAS score at 6, 6–24, 24–48 and 48–72 h were considered. Significance was assessed at the 5% level.

Results and Conclusion:

VAS scores were significantly high (P=0.001) in the femoral group at 6 h, after which there was a declining trend, and scores were essentially similar from 24 h. Common side-effects were more common in the CEA group. Our study shows that CFB gives equivalent analgesia compared with CEA in TKR patients with clinically meaningful decrease in side-effects.

Neuropathic symptoms following continuous popliteal block after foot and ankle surgery

BACKGROUND

Continuous perineural blocks are increasingly popular for postoperative pain control. While the reported incidence of neuropathic symptoms has been low, the experience of the lead author suggested it may be much higher. The objectives of this study were to elucidate the incidence of patient-reported neuropathic symptoms following continuous popliteal block (CPB) for postoperative pain control in patients undergoing foot and ankle surgery, to characterize these symptoms and to identify preoperative risk factors.

METHODS

A prospective cohort study of 147 surgical patients undergoing significant foot and ankle procedures was carried out. Patients were followed for 8 months post-surgery. Preoperative/perioperative questionnaires were completed by anesthesiologists. Patients completed questionnaires at 2, 6, 14, and 34 weeks. Multivariable logistic regression analysis using Generalized Estimating Equations (GEE) was used to examine risk factors for neuropathy.

RESULTS

The prevalence of neuropathic symptoms at 2 weeks was 41% (95% CI, 33% to 49%) decreasing to 24% (95% CI, 15.4% to 32.5%) at 34 weeks. Multivariable analyses revealed that tourniquet placement, tourniquet time, use of prophylactic antibiotics, type of anesthesia, level of training in anesthesiology, patient history of chronic pain and patient age were not significantly associated with neuropathy. Smokers were more likely to report neuropathic symptoms (adjusted OR, 2.25; 95% CI, 0.96 to 5.33).

CONCLUSION

The incidence of neuropathic symptoms may be much higher than previously reported. Smoking may be a risk factor for the development of neuropathic symptoms.

Lithium attenuates bupivacaine-induced neurotoxicity in vitro through phosphatidylinositol-3-kinase/threonine-serine protein kinase B- and extracellular signal-regulated kinase-dependent mechanisms

Local anesthetics (LAs) are necessary for the regional anesthesia, spinal anesthesia, and pain management. However, the application of LAs may cause neurotoxicity and result in postoperative neurological complications. Lithium is a mood stabilizer for the treatment of bipolar disorder and may exert neuroprotective effects. In this study, we evaluated the effects of lithium on bupivacaine (a frequently used LAs)-induced injury in mouse neuroblastoma neuro 2a (N2a) cells. N2a cells were treated with bupivacaine in the presence or absence of lithium. After treatment, the cell injury was evaluated by examination of viability, morphology changes, and nuclear condensation. The levels of mitochondrial transmembrane potential (ΔΨm) and activation of phosphatidylinositol-3-kinase (PI3K)/ threonine-serine protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) were also examined. In a separate experiment, we investigated the effect of Akt and ERK inhibition on cell injury after bupivacaine and lithium treatment. Pretreatment of N2a cells with lithium significantly attenuated bupivacaine-induced cell injury. Lithium pretreatment completely reversed the suppression of PI3K/Akt and ERK signalings and significantly prevented the decline of ΔΨm in N2a cells after bupivacaine treatment. More importantly, pharmacological inhibition of Akt and ERK diminished the protective effect of lithium against bupivacaine-induced neuronal death. Our data suggest that lithium pretreatment provides a protective effect on bupivacaine-induced neuronal cell injury. This action of lithium is mediated through, at least in part, the activating of PI3K/Akt- and ERK-dependent mechanisms. Because lithium is a clinically proved safety drug for neurons, it is worthwhile to identify whether coadministration of LAs with lithium will decrease the risks of LAs-induced postoperative neurological complications in clinic practice.

Delayed appearance of hypaesthesia and paralysis after femoral nerve block

We report on a female patient who underwent an arthroscopy of the right knee and was given a continuous femoral nerve block catheter. The postoperative course was initially unremarkable, but when postoperative mobilisation was commenced, 18 hours after removal of the catheter, the patient noticed paralysis and hypaesthesia. Examination confirmed the diagnosis of femoral nerve dysfunction. Colour duplex sonography of the femoral artery and computed tomography of the lumbar spine and pelvis yielded no pathological findings. Overnight the neurological deficits decreased without therapy and were finally no longer detectable. We speculate that during the administration of the local anaesthetic a depot formed, localised in the medial femoral intermuscular septa, which was leaked after first mobilisation. To our knowledge no similar case has been published up to now. We conclude that patients who are treated with a nerve block should be informed and physician should be aware that delayed neurological deficits are possible.

Regional Anaesthesia and Analgesia on the Front Line

Deployment to a combat zone with the military poses many challenges to the anaesthetist. One of these challenges is the safe, rapid and comfortable initial wound management and repatriation of wounded combat soldiers to their home country or tertiary treatment facility for definitive care and rehabilitation. The current conflict in Afghanistan is associated with injury patterns that differ from wars such as Vietnam or Korea. This report describes the experience of an Australian military anaesthetist and the value of regional anaesthesia and analgesia for the care of the wounded combat soldier.

Neurological complication analysis of 1000 ultrasound guided peripheral nerve blocks for elective orthopaedic surgery: a prospective study

Little data exists regarding the frequency of neurological complications following ultrasound guided peripheral nerve blockade. Therefore, we studied single injection and continuous ultrasound guided interscalene, supraclavicular, infraclavicular, femoral and sciatic nerve blocks in patients undergoing orthopaedic extremity surgery. All patients were contacted during postoperative weeks 2-4 and questioned for numbness or altered sensation anywhere in the involved extremity, and pain or weakness unrelated to surgery. The presumed aetiology of symptoms was based on the collective agreement of principal investigator, primary surgeon and a neurologist. Multivariate analysis was performed for characteristics potentially important in the causation of neurological complications. Of 1010 consecutive blocks, successful follow up between weeks 2 and 4 occurred in 98.6%. New, all-cause, neurological symptoms were present in 56/690 blocks (8.2%) at day 10, 37/1010 (3.7%) at 1 month and 6/1010 (0.6%) at 6 months. Most symptoms were due to causes unrelated to the block. Of 452 patients directly questioned at the time of the block, new neurological symptoms were more common in patients who experienced procedure-induced paraesthesia (odds ratio = 1.7, p = 0.029). The postoperative neurological symptom rate in this series is very similar to those previously reported following traditional techniques.