Perioperative peripheral nerve injuries: a retrospective study of 380,680 cases during a 10-year period at a single institution. Anesthesiology. 2009;111:490-497. [PMID: 19672188 DOI: 10.1097/aln.0b013e3181af61cb]

Local Anesthetic-Induced Neurotoxicity

This review summarizes current knowledge concerning incidence, risk factors, and mechanisms of perioperative nerve injury, with focus on local anesthetic-induced neurotoxicity. Perioperative nerve injury is a complex phenomenon and can be caused by a number of clinical factors. Anesthetic risk factors for perioperative nerve injury include regional block technique, patient risk factors, and local anesthetic-induced neurotoxicity. Surgery can lead to nerve damage by use of tourniquets or by direct mechanical stress on nerves, such as traction, transection, compression, contusion, ischemia, and stretching. Current literature suggests that the majority of perioperative nerve injuries are unrelated to regional anesthesia. Besides the blockade of sodium channels which is responsible for the anesthetic effect, systemic local anesthetics can have a positive influence on the inflammatory response and the hemostatic system in the perioperative period. However, next to these beneficial effects, local anesthetics exhibit time and dose-dependent toxicity to a variety of tissues, including nerves. There is equivocal experimental evidence that the toxicity varies among local anesthetics. Even though the precise order of events during local anesthetic-induced neurotoxicity is not clear, possible cellular mechanisms have been identified. These include the intrinsic caspase-pathway, PI3K-pathway, and MAPK-pathways. Further research will need to determine whether these pathways are non-specifically activated by local anesthetics, or whether there is a single common precipitating factor.

Neuraxial vs general anaesthesia for total hip and total knee arthroplasty: a systematic review of comparative-effectiveness research

BACKGROUND

This systematic review evaluated the evidence comparing patient-important outcomes in spinal or epidural vs general anaesthesia for total hip and total knee arthroplasty.

METHODS

MEDLINE, Ovid EMBASE, EBSCO CINAHL, Thomson Reuters Web of Science, and the Cochrane Central Register of Controlled Trials from inception until March 2015 were searched. Eligible randomized controlled trials or prospective comparative studies investigating mortality, major morbidity, and patient-experience outcomes directly comparing neuraxial (spinal or epidural) with general anaesthesia for total hip arthroplasty, total knee arthroplasty, or both were included. Independent reviewers working in duplicate extracted study characteristics, validity, and outcomes data. Meta-analysis was conducted using the random-effects model.

RESULTS

We included 29 studies involving 10 488 patients. Compared with general anaesthesia, neuraxial anaesthesia significantly reduced length of stay (weighted mean difference -0.40 days; 95% confidence interval -0.76 to -0.03; P=0.03; I2 73%; 12 studies). No statistically significant differences were found between neuraxial and general anaesthesia for mortality, surgical duration, surgical site or chest infections, nerve palsies, postoperative nausea and vomiting, or thromboembolic disease when antithrombotic prophylaxis was used. Subgroup analyses failed to find statistically significant interactions (P>0.05) based on risk of bias, type of surgery, or type of neuraxial anaesthesia.

CONCLUSION

Neuraxial anaesthesia for total hip or total knee arthroplasty, or both appears equally effective without increased morbidity when compared with general anaesthesia. There is limited quantitative evidence to suggest that neuraxial anaesthesia is associated with improved perioperative outcomes. Future investigations should compare intermediate and long-term outcome differences to better inform anaesthesiologists, surgeons, and patients on importance of anaesthetic selection.

Postoperative complications of spine surgery

A variety of surgical approaches are available for the treatment of spine diseases. Complications can arise intraoperatively, in the immediate postoperative period, or in a delayed fashion. These complications may lead to severe or even permanent morbidity if left unrecognized and untreated [1-4]. Here we review a range of complications in the early postoperative period from more benign complications such as postoperative nausea and vomiting (PONV) to more feared complications leading to permanent loss of neurological function or death [5]. Perioperative pain management is covered in a separate review (Chapter 8).

Is the lateral jack-knife position responsible for cases of transient neurapraxia?

OBJECT

The lateral jack-knife position is often used during transpsoas surgery to improve access to the spine. Postoperative neurological signs and symptoms are very common after such procedures, and the mechanism is not adequately understood. The objective of this study is to assess if the lateral jack-knife position alone can cause neurapraxia. This study compares neurological status at baseline and after positioning in the 25° right lateral jack-knife (RLJK) and the right lateral decubitus (RLD) position.

METHODS

Fifty healthy volunteers, ages 21 to 35, were randomly assigned to one of 2 groups: Group A (RLD) and Group B (RLJK). Motor and sensory testing was performed prior to positioning. Subjects were placed in the RLD or RLJK position, according to group assignment, for 60 minutes. Motor testing was performed immediately after this 60-minute period and again 60 minutes thereafter. Sensory testing was performed immediately after the 60-minute period and every 15 minutes thereafter, for a total of 5 times. Motor testing was performed by a physical therapist who was blinded to group assignment. A follow-up call was made 7 days after the positioning sessions.

RESULTS

Motor deficits were observed in the nondependent lower limb in 100% of the subjects in Group B, and no motor deficits were seen in Group A. Statistically significant differences (p < 0.05) were found between the 2 groups with respect to the performance on the 10-repetition maximum test immediately immediately and 60 minutes after positioning. Subjects in Group B had a 10%–70% (average 34.8%) decrease in knee extension strength and 20%–80% (average 43%) decrease in hip flexion strength in the nondependent limb.

Sensory abnormalities were observed in the nondependent lower limb in 98% of the subjects in Group B. Thirty-six percent of the Group B subjects still exhibited sensory deficits after the 60-minute recovery period. No symptoms were reported by any subject during the follow-up calls 7 days after positioning.

CONCLUSIONS

Twenty-five degrees of right lateral jack-knife positioning for 60 minutes results in neurapraxia of the nondependent lower extremity. Our results support the hypothesis that jack-knife positioning alone can cause postoperative neurological symptoms.

Principles of Neuro-anesthesia in Neurosurgery for Intensive Care Unit Nurses

As neurosurgical interventions and procedures are advancing, so is the specialty of neuro-anesthesia. The neurosurgeon and the neuro-anesthetist are focused on providing each patient with the best possible outcome. Throughout the surgery, the main priorities of the neuro-anesthetist are patient safety, patient well-being, surgical field exposure, and patient positioning. Potential postoperative complications include nausea and vomiting. Postoperative visual loss is a complication of neurosurgery, most specifically spine surgery, whose origins are unknown. Postoperative considerations for the intensive care unit nurse should include receiving a thorough clinical handoff from the anesthesia provider to ensure care continuity and patient safety.

Prevention of perioperative limb neuropathies in abdominal free flap breast reconstruction

BACKGROUND AND AIMS

Perioperative peripheral neuropathies are a significant cause of post-operative morbidity in patients undergoing prolonged procedures. The aims of this study were to determine the incidence and possible causes of peripheral neuropathy in patients undergoing abdominal free flap breast reconstruction and to develop methods of ameliorating this problem.

METHODS

A 4-year retrospective study of patients undergoing abdominal free flap breast reconstruction by a single surgeon and anaesthetist was undertaken to determine the incidence and potential causes of perioperative neuropathy. A new positioning protocol was introduced to minimise the stretch on the brachial plexus and to protect peripheral nerves from compression forces. In addition, regular intraoperative physiotherapy was introduced. A prospective study was then conducted on patients managed by the same team to evaluate the effect of this change in practice on the subsequent incidence of peripheral neuropathies.

RESULTS

Over the 4-year retrospective period, 93 consecutive patients underwent abdominal free flap breast reconstruction, six of whom (6.5%) developed a peripheral neuropathy. Following the introduction of the new positioning protocol, prospective data collected on 65 consecutive patients showed no further occurrences of perioperative neuropathy (p = 0.04). There were no significant differences in the characteristics between the two cohorts.

CONCLUSION

Perioperative peripheral neuropathy in abdominal free flap breast reconstruction is a preventable problem. This paper presents a peripheral neuropathy prevention protocol for managing these patients.

Pathophysiology and Etiology of Nerve Injury Following Peripheral Nerve Blockade

This review synthesizes anatomical, anesthetic, surgical, and patient factors that may contribute to neurologic complications associated with peripheral nerve blockade. Peripheral nerves have anatomical features unique to a given location that may influence risk of injury. Peripheral nerve blockade-related peripheral nerve injury (PNI) is most severe with intrafascicular injection. Surgery and its associated requirements such as positioning and tourniquet have specific risks. Patients with preexisting neuropathy may be at an increased risk of postoperative neurologic dysfunction. Distinguishing potential causes of PNI require clinical assessment and investigation; a definitive diagnosis, however, is not always possible. Fortunately, most postoperative neurologic dysfunction appears to resolve with time, and the incidence of serious long-term nerve injury directly attributable to peripheral nerve blockade is relatively uncommon. Nonetheless, despite the use of ultrasound guidance, the risk of block-related PNI remains unchanged.

WHAT'S NEW

Since the 2008 Practice Advisory, new information has been published, furthering our understanding of the microanatomy of peripheral nerves, mechanisms of peripheral nerve injection injury, toxicity of local anesthetics, the etiology of and monitoring methods, and technologies that may decrease the risk of nerve block-related peripheral nerve injury.

Detection of Position-Related Sciatic Nerve Dysfunction by Somatosensory Evoked Potentials During Spinal Surgery

It is well established that intraoperative somatosensory evoked potentials (SSEPs) are sensitive to plexus and peripheral nerve dysfunction related to malpositioning of patients during spinal surgery. While most reports focus on upper extremity nerve or brachial plexus effects, there is very little on detection of sciatic nerve compromise. Recording of the SSEP at the popliteal fossa is a common strategy to aid in troubleshooting stimulus-related problems or distal peripheral tibial nerve failure; yet position-related sciatic nerve effects may not be realized by changes in the popliteal fossa response. Three posterior lumbar surgeries are reviewed in which there was evidence of proximal lower extremity peripheral nerve dysfunction related to positioning. Loss of posterior tibial nerve SSEPs with preservation of the peripheral popliteal fossa response recording occurred in the absence of critical surgical manipulations. Efforts at repositioning and release of tension on the lower limbs promptly resulted in recovey of lost responses. Two of the three cases involved patients in a kneeling position with a tight strap across the posterior thigh. Standard SSEP recordings used in intraoperative neuromonitoring do not specifically localize intraoperative changes to the sciatic nerve; thus, such changes affecting SSEPs above the popliteal fossa mimic iatrogenic changes occurring at the surgical site. These case reports show that when the stage of surgery does not support iatrogenic changes, malpositioning affecting sciatic nerve should be considered, especially for patients placed in a kneeling position on an Andrews frame.

Role of regional anesthesia in orthopedic trauma

Regional anesthesia plays a key role in the treatment of patients with orthopedic trauma. Trauma-induced pain can be in multiple locations, severe, and can predispose the patient to other morbidities. Additional complications as a result of the overdependence on opioids as a primary pain therapy that can be minimized or avoided with the use of regional anesthesia. Both neuraxial and peripheral regional techniques in patients with orthopedic trauma should be incorporated into the patient care plan and recognized as an essential therapeutic intervention in the overall treatment of this unique patient population.

Positioning patients for spine surgery: Avoiding uncommon position-related complications

Positioning patients for spine surgery is pivotal for optimal operating conditions and operative-site exposure. During spine surgery, patients are placed in positions that are not physiologic and may lead to complications. Perioperative peripheral nerve injury (PPNI) and postoperative visual loss (POVL) are rare complications related to patient positioning during spine surgery that result in significant patient disability and functional loss. PPNI is usually due to stretch or compression of the peripheral nerve. PPNI may present as a brachial plexus injury or as an isolated injury of single nerve, most commonly the ulnar nerve. Understanding the etiology, mechanism and pattern of injury with each type of nerve injury is important for the prevention of PPNI. Intraoperative neuromonitoring has been used to detect peripheral nerve conduction abnormalities indicating peripheral nerve stress under general anesthesia and to guide modification of the upper extremity position to prevent PPNI. POVL usually results in permanent visual loss. Most cases are associated with prolonged spine procedures in the prone position under general anesthesia. The most common causes of POVL after spine surgery are ischemic optic neuropathy and central retinal artery occlusion. Posterior ischemic optic neuropathy is the most common cause of POVL after spine surgery. It is important for spine surgeons to be aware of POVL and to participate in safe, collaborative perioperative care of spine patients. Proper education of perioperative staff, combined with clear communication and collaboration while positioning patients in the operating room is the best and safest approach. The prevention of uncommon complications of spine surgery depends primarily on identifying high-risk patients, proper positioning and optimal intraoperative management of physiological parameters. Modification of risk factors extrinsic to the patient may help reduce the incidence of PPNI and POVL.

Use of somatosensory evoked potentials to detect and prevent impending brachial plexus injury during surgical positioning for the treatment of supratentorial pathologies

Somatosensory evoked potentials (SSEPs) are widely utilized for the intraoperative detection and prevention of nerve conduction injuries. Their use in identifying position-related injuries to the brachial plexus in patients undergoing supine craniotomies for the treatment of supratentorial pathology is not well documented. This case series describes three instances of unilateral upper extremity SSEP changes in patients positioned for supine craniotomies. In all three cases SSEP responses improved after repositioning. None of the patients exhibited new neurological deficits post-operatively. This case series highlights the importance of vigilant monitoring in the period after final positioning and demonstrates the usefulness of SSEPs as a tool to aid in the early detection and prevention of impending position-related nerve injury.

Ipsilateral inflammatory neuropathy after hip surgery

OBJECTIVE

To identify whether new ipsilateral weakness after hip surgery may be due to an inflammatory as opposed to a mechanical process.

PATIENTS AND METHODS

Seven patients (8 hip surgeries) seen between July 1, 2008, and June 30, 2011, developed unexplained ipsilateral leg weakness and pain within 1 month of hip surgery, mimicking mechanical etiologies. Cutaneous sensory nerve biopsy distant from the site of surgery was performed on all the patients. Patient medical records were reviewed for the clinical, electrophysiologic, radiologic, and pathologic features of the new neuropathy.

RESULTS

Results of all the nerve biopsies were abnormal, showing axonal damage (7 patients), inflammation (7 patients), signs of ischemic injury (7 patients), and nerve microvasculitis (6 patients). Six patients were treated with intravenous methylprednisolone. At median follow-up of 6 months, 6 patients showed improvement in function and pain.

CONCLUSION

In this case series, we demonstrate that inflammatory neuropathy is an important etiologic consideration in some patients with ipsilateral weakness and pain after hip surgery. In these patients, the inflammatory mechanism was ischemic injury due to microvasculitis. Identification of these patients through clinical suspicion and subsequent nerve biopsy may lead to improved outcomes with prompt initiation of immunotherapy.

Perioperative upper extremity peripheral nerve traction injuries

Peripheral nerve traction injuries may occur after surgical care and can involve any of the upper extremity large peripheral nerves. In this review, injuries after shoulder or elbow surgical intervention are discussed. Understanding the varying mechanisms of injury as well as classification is imperative for preoperative risk stratification as well as management.

Analysis of patient injury based on anesthesiology closed claims data from a major malpractice insurer

INTRODUCTION

The analysis of malpractice claims can provide risk managers with a detailed view of patient mortality and morbidity. The data comes from many institutions, encompasses a diverse group of practitioners and practice settings, and contains detailed clinical information. Analysis can help identify patterns of injury, risk factors, and rare and sentinel events.

METHODS

We examined most recent anesthesia closed claims data collected by The Doctors Company, a large national malpractice insurer. We analyzed data from claims closed between 2007 and 2012. Each claim underwent a review by physician and nurse experts, and was then coded using the Comprehensive Risk Intelligence Tool. Injury distribution and association between the injury and patient comorbidity were also examined.

RESULTS

A total of 607 claims were analyzed. Most frequent injuries were teeth damage (20.8%), death (18.3%), nerve damage (13.5%), organ damage (12.7%), pain (10.9%), and arrest (10.7%). Obesity was most frequently identified as a contributing factor leading to a claim. Injury-to-claim rates were highest in hospitals with fewer than 100 beds, while ambulatory surgery centers had the lowest death-to-claim rate (12%). Average indemnity for an anesthesia claim was $309 066, compared to $291 000 for all physician specialties.

CONCLUSIONS

The most frequent claims were death and nerve damage when teeth damage was excluded. Obesity impacted anesthesia outcomes more frequently than did other comorbidities. Although there were fewer claims from the smaller hospitals, those claims had higher rates of mortality and nerve damage compared to larger-size hospitals. Further analysis is needed to evaluate these trends as well as impact of specific patient comorbidities on anesthesia outcomes.

Of rough starts and smooth finishes: correlations between post-anesthesia care unit and postoperative days 1-5 pain scores

OBJECTIVE

The goal of this project was to explore the association between post-anesthesia care unit (PACU) pain scores recorded within the first and second hour of the end of surgery with maximum and median pain scores recorded on postoperative days (PODs) 1 through 5.

DESIGN

This study was a retrospective cohort study of clinically documented pain scores in a mixed surgical population.

SETTING

This study was set in a single tertiary-care teaching hospital over a 1-year time period.

PATIENTS

All patients were adult patients undergoing a single, non-ambulatory, non-obstetric surgical procedure.

MEASURES

Pain scores, measured using the numerical rating scale, from PODs 0 through 5 were obtained from an integrated data repository. Kendall's Tau-b correlations were then calculated between maximum pain scores occurring within each of the two PACU time periods and maximum and median pain scores in each of the five ensuing PODs.

RESULTS

A total of 349,797 pain scores from 8,332 patients were reviewed. Correlations between maximum pain score by time period demonstrated a significant and high correlation at Tau-b = 0.86, between 1-hour PACU pain scores and 2-hour PACU pain scores. However, the correlation of maximum pain scores recorded in the PACU with those recorded on PODs 1 through 5 was significantly lower, ranging from 0.19 to 0.27. The correlation of maximum PACU pain score with median pain scores recorded on PODs 1 through 5 ranged from 0.22 to 0.29. The correlation structures of the PODs 1 through 5 median pain scores may be consistent with an autoregressive pattern.

CONCLUSIONS

Maximum scores measured within the PACU likely reflect a set of circumstances distinct from those experienced on PODs 1 through 5.

Neurologic complications of anesthesia: A practical approach

Neurologic complications related to anesthesia are infrequent but can be serious. Neurologists are often consulted to evaluate patients with postoperative symptoms and must be ready to discriminate those truly caused by the anesthetic drug or procedure from the more common postoperative complications that are unrelated to the anesthesia itself. This practical review relies on cases to illustrate common reasons for neurologic consultation in the postsurgical setting. It also briefly summarizes what to expect when patients with central or peripheral neurologic disease undergo surgery under general or regional anesthesia.

Preventing perioperative peripheral nerve injuries

Peripheral nerve injuries are largely preventable injuries that can result from incorrect patient positioning during surgery. Patients who are diabetic, are extremely thin or obese, use tobacco, or undergo surgery lasting more than four hours are at increased risk for developing these injuries. When peripheral nerve injuries occur, patients may experience numbness, burning, or tingling and may have difficulty getting out of bed, walking, gripping objects, or raising their arms. These symptoms can interrupt activities of daily living and impede recovery. Signs and symptoms of peripheral nerve injury may appear within 24 to 48 hours of surgery or may take as long as a week to appear. Careful attention to body alignment and proper padding of bony prominences when positioning patients for surgery is necessary to prevent peripheral nerve injury. The use of a preoperative assessment tool to identify at-risk patients, collaboration between physical therapy and OR staff members regarding patient positioning, and neurophysiological monitoring can help prevent peripheral nerve injuries.

Neurologic complications of anesthesia

Neurologic complications after anesthesia are relatively uncommon but occasionally severe. Intraoperative intracranial hypertension in patients with brain masses, delayed arousal, and postoperative delirium and cognitive dysfunction are among the main complications of general anesthesia. Neuropathy and transient gluteal and leg pain are the most frequent complications of regional blockade. Seizures are infrequent with both anesthesia modalities. Patients with primary neurologic disorders, such as neurodegenerative or neuromuscular conditions, can be at risk for specific complications, and the anesthesia plan must be cautiously adjusted in these patients. In the neurointensive care unit, the complications from large doses of anesthetic agents used for suppression of seizures or control of intracranial pressure are different from those seen perioperatively. Propofol infusion syndrome can be life-threatening when administered for those indications.

Iatrogenic nerve injury in a national no-fault compensation scheme: an observational cohort study

BACKGROUND

Iatrogenic nerve injury causes distress and disability, and often leads to litigation. The scale and profile of these injuries has only be estimated from published case reports/series and analyses of medicolegal claims.

AIM

  To determine the current spectrum of iatrogenic nerve injury in New Zealand by analysing treatment injury claims accepted by a national no-fault compensation scheme.

METHODS

The Accident Compensation Corporation (ACC) provides national no-fault personal accident insurance cover, which extends to patients who have sustained a treatment injury from a registered healthcare professional. Nerve injury claims identified from 5227 treatment injury claims accepted by the ACC in 2009 were analysed.

RESULTS

From 327 claims, 292 (89.3%) documenting 313 iatrogenic nerve injuries contained sufficient information for analysis. Of these, 211 (67.4%) occurred in 11 surgical specialties, particularly orthopaedics and general surgery; the remainder involved phlebotomy services, anaesthesia and various medical specialties. The commonest causes of injury were malpositioning (n = 40), venepuncture (n = 26), intravenous cannulation (n = 21) and hip arthroplasty (n = 21). Most commonly injured were the median nerve and nerve roots (n = 32 each), brachial plexus (n = 26), and the ulnar nerve (n = 25). At least 34 (11.6%) patients were referred for surgical management of their nerve injury.

CONCLUSIONS

Iatrogenic nerve injuries are not rare and occur in almost all branches of medicine, with malpositioning under general anaesthesia and venepuncture as leading causes. Some of these injuries are probably unavoidable, but greater awareness of which nerves are at risk and in what context should facilitate the development and/or wider implementation of preventive strategies.

[Neurologic complications of central neuraxial blocks]

Central neuraxial blocks, which are associated with a low incidence of complications, are safe. When complications do occur, however, the resulting morbidity and mortality is considerable. The reported incidence of complications in all series is under 4 per 10000 patients, but given the absence of formal registries and notification procedures, which have legal implications, the real rate of occurrence of these rare events is uncertain. We searched the literature through PubMed and the Cochrane Plus Library for a 5-year period, using the search terms epidural anesthesia AND safety, spinal anesthesia AND safety, complications AND epidural anesthesia, complications AND spinal anesthesia, neurologic complications AND epidural anesthesia, and neurologic complications AND spinal anesthesia. Neuraxial injury after a central blockade may be the result of anatomical and/or physiological lesions affecting the spinal cord, spinal nerves, nerve roots, or blood supply. The pathophysiology of neuraxial injury may be related to mechanical, ischemic, or neurotoxic damage or any combination. When a complication occurs, factors related to the technique will have interacted with pre-existing patient-related conditions. Various scientific societies have published guidelines for managing the complications of regional anesthesia. Recently published clinical practice guidelines recommend ultrasound imaging as a useful tool in performing a central neuraxial block.

Safety of amide local anesthetics: new trends

IMPORTANCE OF THE FIELD

Local anesthetics have become one of the most common drugs used in daily practice worldwide. Neurologic and cardiovascular events are the most frequent adverse reactions related to local anesthetics use. Recently, new trends have been developed on this topic.

AREAS COVERED IN THIS REVIEW

We performed an overview of the data available so far on local anesthetics adverse reactions. Relevant literature was identified using PubMed search of articles published up to November 2009, including experimental studies, case reports or clinical studies when available. Search terms included: 'local anaesthetics', 'adverse drug reaction', 'pharmacovigilance' and 'complication'.

WHAT THE READER WILL GAIN

Neurologic, cardiovascular and allergic reactions remain the most frequent adverse drug reactions related to local anesthetics in the literature. Studies based on pharmacovigilance systems have highlighted the frequency of adverse reactions little known until now, such as failure of block. Lipid emulsions are included into algorithm for cardiac resuscitation. Recent studies have demonstrated the myotoxicity and chondrotoxic effects of long-acting local anesthetics.

TAKE HOME MESSAGE

Physicians must keep in mind all these adverse reactions to better prevent their occurrence and give the most appropriate treatment.