Effects of anesthesia on pain after lower-limb amputation

Anesthetic management for lower extremity vascular bypass procedures: The impact of general or regional anesthesia on clinical outcomes

PURPOSE

Postoperative complications after major surgery, especially vascular procedures, are associated with a significant increase in costs and mortality. Previous studies evaluating general anesthesia versus regional or neuraxial anesthesia for infrainguinal bypass have produced conflicting results. The main aim of the present study is to review current evidence on the application of regional or general anesthesia in patients undergoing infrainguinal bypass surgery and its potential favorable effects on postoperative outcomes.

CONTENTS

Patients undergoing vascular surgery often have multiple comorbidities, and it is important to outline both benefits and risks of regional anesthesia techniques. Neuraxial anesthesia in vascular surgery allows overall avoidance of general anesthesia and does provide short-term benefits beyond analgesia. Previous observational studies suggest that neuraxial anesthesia for lower limb revascularization may reduce morbidity and length of stay. However, evidence of long-term benefits is lacking in most procedures and further work is still warranted.

CONCLUSIONS

Neuraxial anesthesia is usually an effective anesthesia technique for infrainguinal bypass surgery. Elderly patients and those with underlying respiratory problems may display some benefit from neuraxial anesthesia. Further evaluation within institutions should be performed to identify which patients would most benefit from regional techniques. Notably, systemic antithrombotic and anticoagulation therapy is common among this population and may affect anesthetic choices.

Continuous peripheral nerve blocks for analgesia of ventilated critically ill patients with multiple trauma: a prospective randomized study

BACKGROUND

Sedation of ventilated critically ill trauma patients requires high doses of opioids and hypnotics. We aimed to compare the consumption of opioids and hypnotics, and patient outcomes using sedation with or without continuous regional analgesia (CRA).

METHODS

Multiple trauma-ventilated patients were included. The patients were randomized to receive an intravenous analgesia (control group) or an addition of CRA within 24h of admission. A traumatic brain injury (TBI) patients group was analyzed. The primary endpoint was the cumulative consumption of sufentanil at 2 days of admission. Secondary endpoints were cumulative and daily consumption of sufentanil and midazolam, duration of mechanical ventilation, intensive care unit (ICU) stay, and safety of CRA management.

RESULTS

Seventy six patients were analyzed: 40 (67.5% males) in the control group and 36 (72% males) in the CRA group, respectively. The median [IQR] Injury Severity Score was 30.5 [23.5-38.5] and 26.0 [22.0-41.0]. The consumption of sufentanil at 48h was 725 [465-960] μg/48h versus 670 [510-940] μg/48h (p = 0.16). Daily consumption did not differ between the groups except on day 1 when consumption of sufentanil was 360 [270-480] μg vs. 480 [352-535] μg (p = 0.03). Consumptions of midazolam did not differ between the groups. No difference was noted between the groups according to the secondary endpoints.

CONCLUSIONS

CRA does not decrease significantly sufentanil and midazolam consumption within the first 5 days after ICU admission in multiple trauma-ventilated patients. The use of peripheral nerve blocks in heavily sedated and ventilated trauma patients in the ICU seems safe.

Opioid consumption and pain in patients with gynecological cancer who underwent spinal anesthesia vs. general anesthesia for interstitial brachytherapy

AIMS

Interstitial brachytherapy (ISBT) is an effective option for delivering conformal high dose radiation to the target volume with better organ-at risk sparing but is thought to be more invasive and painful than other methods. This study investigated pain levels and opioid consumption in patients who received spinal anesthesia (SA) or general anesthesia (GA) for their ISBT.

MATERIALS AND METHODS

Patients that underwent ISBT from April 2014 to September 2018 were analyzed from a prospective institutional database. The most prevalent malignancies were cervical (45%), recurrent endometrial (27%) and vaginal (20%) cancers. Baseline patient characteristics, radiation treatment details, anesthesia records, and inpatient charts were obtained. Opioid consumption was quantified as oral morphine equivalent per day (OMEq/day) from implantation until removal. Pain score levels were collected by using an 11-point scoring system.

RESULTS

Ninety nine patients received GA and 40 patients received SA as their anesthesia for ISBT. During their first admission, 76 patients (55%) required intravenous opioids. Patients receiving SA had significantly lower mean pain scores on the morning of their procedure 6 (Interquartile range [IQR] 2-8) vs. 0 (IQR: 0-1); p < 0.001]. Pain did not significantly differ between cohorts at any other time. During the first admission, SA patients had a lower median opioid usage of 23 (IQR: 9-47) mg/day compared to GA patients at 38 (IQR: 21-71) mg/day (p = 0.011). No difference in opioid consumption was seen during subsequent admissions.

CONCLUSIONS

In patients undergoing ISBT, SA provides better immediate pain control post insertion compared to GA. Patients who received SA used lower amounts of opioids during their first ISBT insertion.

An Algorithm Approach to Phantom Limb Pain

Phantom limb pain (PLP) is a common condition that occurs following both upper and lower limb amputation. First recognized and described in 1551 by Ambroise Pare, research into its underlying pathology and effective treatments remains a very active and growing field. To date, however, there is little consensus regarding the optimal management of phantom limb pain. With few large well-designed clinical trials of which to make treatment recommendations, as well as significant heterogeneity in clinical response to available treatments, the management of PLP remains challenging. Below we summarize the current state of knowledge in the field, as well as propose an algorithm for the approach to the treatment of PLP.

The Role of Regional Anesthesia in the Development of Chronic Pain: a Review of Literature

Purpose of Review

The acute management of pain using regional anesthesia techniques may prevent the development of persistent postsurgical pain (PPP), ultimately improving patient outcomes and enhancing overall quality of life in postsurgical patients. The purpose of this review is to describe the current literature regarding the role of regional anesthesia techniques in the perioperative setting to address and prevent PPP.

Recent Findings

Data was collected and analyzed using results from randomized controlled studies stratified into categories based on different surgical subspecialties. Conclusions were drawn from each surgical category regarding the role of regional anesthesia and/or local analgesia in acute and chronic pain management on the long-term results seen in the studies analyzed.

Summary

Preoperative consultations and optimized perioperative analgesia using regional anesthesia and local analgesia play a fundamental role preventing and treating postoperative pain after many types of surgery by managing pain in the acute setting to mitigate the future development of PPP. Additional studies in different surgical subspecialties are needed to confirm the role regional anesthesia plays in chronic postsurgical pain (CPSP) prevention.

Bilateral brachial plexus block as alternative to general anaesthesia in high-risk patient; a case report and literature review

Introduction

Bilateral brachial plexus blocks can be an alternative to general anaesthesia in the surgery of arm, forearm, wrist, or hand. This study aims to report a case in which a risky patient underwent amputation surgery under regional anaesthesia.

Case presentation

A 64-year-old male was admitted to the hospital for an amputation operation. Ultrasonography revealed normal findings regarding internal organs, aside from grade II increased echogenicity of both kidneys and a small bladder cyst. Echocardiography revealed mildly left ventricular dilation, moderate systolic left ventricular dysfunction, ejection fraction 38%, left ventricular wall hypokinesia with left ventricular dilation. The amputation was performed under a bilateral supraclavicular brachial plexus block with the guidance of ultrasound.

Discussion

Theoretically, there are some advantages to regional anaesthesia in comparison to general anaesthesia, such as decreasing the ordinary body response to stress in the presence of low levels of cortisol and catecholamines, increasing blood flow and peripheral vasodilatation, decreasing hypercoagulability, lower risk of arterial and venous thrombosis and it aids to prevent endotracheal intubation and mechanical ventilation.

Conclusion

Bilateral brachial plexus blocks, as a type of regional anaesthesia under ultrasound guidance, can be depended upon as a reliable substitute for general anaesthesia in perilous conditions.

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Bilateral brachial plexus blocks (BBPB) are a kind of regional anaesthesia that can be used instead of general anaesthesia.

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Several complications may be encountered during the process of BBPB, including diaphragmatic paralysis.

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In this study, BBPB has been discussed with literature review.

Total Knee Arthroplasty Postsurgical Chronic Pain, Neuropathic Pain, and the Prevalence of Neuropathic Symptoms: A Prospective Observational Study in Turkey

Purpose

Chronic post-surgical pain (CPSP) is a detrimental condition that persists at least two months after surgical procedures and seriously affects patients' quality of life. Although its incidence varies according to operation types and definitions, its prevalence is between 3% and 85%. The purpose of this study is to evaluate the prevalence of CPSP and neuropathic pain in patients undergoing TKA for osteoarthritis.

Patients and Methods

In this study, patients who had undergone total knee arthroplasty (TKA) were examined prospectively and observationally. 42 patients were included in the study. Numeric rate scale (NRS) for developing chronic pain, Douleur Neuropathique 4 (DN-4) questionnaire to evaluate neuropathic pain and symptoms, and von Frey filaments to evaluate mechanical hyperesthesia and alladony.

Results

NRS scores were 1 or higher for all patients. Twenty-seven patients constituted the mild pain group (NRS: 1-4), and 15 patients constituted the moderate pain group (NRS: 4-7). The number of patients defined as having "neuropathic pain," according to DN-4 scores, was 17 (40.4%; DN-4 ≥ 4). The moderate pain group reported greater severity of neuropathic symptoms on average than the mild pain group (p = 0.039). When patients knees affected by TKA were divided into suprapatellar, patellar, and infrapatellar regions and evaluated with von Frey filaments, a significant difference was found between the three regions (p < 0.05).

Conclusion

In this study, we showed-unlike other studies-that the rate of neuropathic pain was higher among CPSP patients, and all patients had neuropathic symptoms. In evaluating patients knees with von Frey filaments, we showed that the neuropathic component of patients' pain occurred mostly in the knee's infrapatellar region. Although the incidence of CPSP and neuropathic pain in these patients was higher than expected, we think CPSP, its diagnosis, and its treatment present an important issue that requires further examination.

Surgical prevention of terminal neuroma and phantom limb pain: a literature review

The incidence of extremity amputation is estimated at about 200,000 cases annually. Over 25% of patients suffer from terminal neuroma or phantom limb pain (TNPLP), resulting in pain, inability to wear a prosthetic device, and lost work. Once TNPLP develops, there is no definitive cure. Therefore, there has been an emerging focus on TNPLP prevention. We examined the current literature on TNPLP prevention in patients undergoing extremity amputation. A literature review was performed using Ovid Medline, Cochrane Collaboration Library, and Google Scholar to identify all original studies that addressed surgical prophylaxis against TNPLP. The search was conducted using both Medical Subject Headings and free-text using the terms “phantom limb pain,” “amputation neuroma,” and “surgical prevention of amputation neuroma.” Fifteen studies met the inclusion criteria, including six prospective trials, two comprehensive literature reviews, four retrospective chart reviews, and three case series/technique reviews. Five techniques were identified, and each was incorporated into a target-based classification system. A small but growing body of literature exists regarding the surgical prevention of TNPLP. Targeted muscle reinnervation (TMR), a form of physiologic target reassignment, has the greatest momentum in the academic surgical community, with multiple recent prospective studies demonstrating superior prevention of TNPLP. Neurorrhaphy and transposition with implantation are supported by less robust evidence, but merit future study as alternatives to TMR.

Effects of different anesthetic techniques on the incidence of phantom limb pain after limb amputation: a population-based retrospective cohort study

Background

General anesthesia (GA) has been considered the anesthetic technique which most frequent leads to phantom limb pain (PLP) after a limb amputation. However, these prior reports were limited by small sample sizes. The aims of this study were to evaluate the incidence of PLP according to the various anesthetic techniques used for limb amputation and also to compare the occurrence of PLP according to amputation etiology using the Korean Health Insurance Review and Assessment Service for large-scale demographic information.

Methods

The claims of patients who underwent limb amputation were reviewed by analyzing the codes used to classify standardized medical behaviors. The patients were categorized into three groups—GA, neuraxial anesthesia (NA), and peripheral nerve block (PNB)—in accordance with the anesthetic technique. The recorded diagnosis was confirmed using the diagnostic codes for PLP registered within one year after the limb amputation.

Results

Finally, 7,613 individuals were analyzed. According to the recorded diagnoses, 362 patients (4.8%) developed PLP after amputation. Among the 2,992 patients exposed to GA, 191 (6.4%) were diagnosed with PLP, whereas 121 (4.3%) of the 2,840 patients anesthetized with NA, and 50 (2.8%) of the 1,781 patients anesthetized under PNB developed PLP. The relative risks were 0.67 (95% confidence interval [CI], 0.53–0.84; P < 0.001) for NA and 0.43 (95% CI, 0.32–0.59; P < 0.001) for PNB.

Conclusions

In this retrospective cohort study, using large-scale population-based databases, the incidence rates of PLP after limb amputations were, in the order of frequency, GA, NA, and PNB.

Regional anesthesia for vascular surgery: does the anesthetic choice influence outcome?

PURPOSE OF REVIEW

Outcomes following surgery are of major importance to clinicians, institutions and most importantly patients. This review examines whether regional anesthesia and analgesia influence outcome after vascular surgery.

RECENT FINDINGS

Large database analyses of contemporary practice suggest that utilizing regional anesthesia for both open and endovascular aortic aneurysm repair, lower limb revascularization and carotid endarterectomy reduces morbidity, length of stay and possibly even mortality. Results from such analyses are limited by an inherent risk of bias but are nevertheless important given the number of patients required in randomized trials to detect differences in rare outcomes. There is minimal evidence that regional anesthesia influences longer term outcomes except for arteriovenous fistula surgery where brachial plexus blocks appear to improve 3-month fistula patency.

SUMMARY

Patients undergoing vascular surgery often have multiple comorbidities and it is important to be able to outline both benefits and risks of regional anesthesia techniques. Regional anesthesia in vascular surgery allows avoidance of general anesthesia and does provide short-term benefits beyond superior analgesia. Evidence of long-term benefits is lacking in most procedures. Further work is required on newer patient centered outcomes.

Pain management in trauma patients affected by the opioid epidemic: A narrative review

Acute and chronic pain in trauma patients remains a challenging entity, particularly in the setting of the escalating opioid epidemic. It has been reported that chronic opioid use increases the likelihood of hospital admissions as a result of traumatic injuries. Furthermore, patients admitted with traumatic injuries have a greater than average risk of developing opioid use disorder after discharge. Practitioners providing care to these patients will encounter the issue of balancing analgesic goals and acute opioid withdrawal with the challenge of reducing postdischarge persistent opioid use. Additionally, the practitioner is faced with the worrisome prospect that inadequate treatment of acute pain may lead to the development of chronic pain and overtreatment may result in opioid dependence. It is therefore imperative to understand and execute alternative nonopioid strategies to maximize the benefits and reduce the risks of analgesic regimens in this patient population. This narrative review will analyze the current literature on pain management in trauma patients and highlight the application of the multimodal approach in potentially reducing the risks of both short- and long-term opioid use. LEVEL OF EVIDENCE: Narrative review, moderate to High.

Targeted muscle reinnervation in oncologic amputees: Early experience of a novel institutional protocol

BACKGROUND

We describe a multidisciplinary approach for comprehensive care of amputees with concurrent targeted muscle reinnervation (TMR) at the time of amputation.

METHODS

Our TMR cohort was compared to a cross-sectional sample of unselected oncologic amputees not treated at our institution (N = 58). Patient-Reported Outcomes Measurement Information System (NRS, PROMIS) were used to assess postamputation pain.

RESULTS

Thirty-one patients underwent amputation with concurrent TMR during the study; 27 patients completed pain surveys; 15 had greater than 1 year follow-up (mean follow-up 14.7 months). Neuroma symptoms occurred significantly less frequently and with less intensity among the TMR cohort. Mean differences for PROMIS pain intensity, behavior, and interference for phantom limb pain (PLP) were 5.855 (95%CI 1.159-10.55; P = .015), 5.896 (95%CI 0.492-11.30; P = .033), and 7.435 (95%CI 1.797-13.07; P = .011) respectively, with lower scores for TMR cohort. For residual limb pain, PROMIS pain intensity, behavior, and interference mean differences were 5.477 (95%CI 0.528-10.42; P = .031), 6.195 (95%CI 0.705-11.69; P = .028), and 6.816 (95%CI 1.438-12.2; P = .014), respectively. Fifty-six percent took opioids before amputation compared to 22% at 1 year postoperatively.

CONCLUSIONS

Multidisciplinary care of amputees including concurrent amputation and TMR, multimodal postoperative pain management, amputee-centered rehabilitation, and peer support demonstrates reduced incidence and severity of neuroma and PLP.

Acute Postoperative Pain Management After Major Limb Amputation in a Pediatric Patient: A Case Report

PURPOSE

Although total prevention of phantom pain is difficult, pediatric patients requiring amputation benefit from an individualized combination of analgesic techniques for phantom pain reduction using a multimodal and interprofessional approach. This is especially useful in the event a single therapy is ineffective for total pain reduction, and may ultimately lead to a reduction in chronic pain development.

DESIGN

Case report with multimodal and interprofessional approach.

METHODS

A 16-year-old patient with synovial sarcoma underwent a right hemipelvectomy and hip disarticulation. The patient had significant preoperative cancer pain requiring high-dose opioid analgesics prior to surgery. An interprofessional multimodal pain management strategy was used for acute and long-term reduction of postoperative phantom pain.

FINDINGS

Although our patient developed acute phantom pain, multimodal therapy reduced immediate pain with resolution by 2 years follow-up.

CONCLUSIONS

An individualized plan using interprofessional teamwork before surgery may provide optimal results in alleviating phantom pain after amputation for pediatric patients.

Factors affecting phantom limb pain in patients undergoing amputation: retrospective study

PURPOSE

The efficacy of preemptive analgesia for prevention of phantom limb pain has been controversial although pain management before amputation is empirically important. The aim of this study was to determine the associated factors with perioperative phantom limb pain.

METHODS

Following approval by the Medical Ethics Committee in our university, medical records of patients receiving limb amputation surgery in our hospital between April 1, 2013 and October 31, 2017 were retrospectively reviewed. To determine which pre-operative factors could affect the development of phantom limb pain, we performed univariate analysis to find candidate factors (p < 0.05), and then did multivariate regression analysis.

RESULTS

Incidence of phantom limb pain was 50% (22/44). There was no difference between the groups in types of anesthesia and post-operative pain levels. The multivariate logistic regression including possible confounders suggested that diabetes mellitus and uncontrollable preoperative pain with non-steroidal anti-inflammatory drugs (NSAIDs) were independently associated with the development of phantom limb pain (Adjusted odds ratio (OR) 0.238 [95% confidential interval (CI) 0.0643-0.883], p = 0.032, Adjusted OR 6.360 [95% CI 1.280-31.50], p = 0.024, respectively).

CONCLUSION

The types of anesthesia and the degree of postoperative pain were not related to the development of phantom limb pain. The present data suggest that insufficient preoperative pain with NSAIDs and diabetes mellitus would give an impact on the development of phantom limb pain.

Phantom limb syndrome induced by combined spinal and epidural anesthesia in patients undergoing elective open gynecological surgery

BACKGROUND

During regional anesthesia, including combined spinal and epidural anesthesia (CSEA), patients may develop a perceptual alteration of limb position known as phantom limb syndrome (PLS). We aimed to identify factors that influence the PLS onset, to explore whether PLS predisposes to other postoperative symptoms, and to document the relationship between PLS and sensorimotor impairment during recovery.

METHODS

Psychological questionnaires for anxiety and depression were completed beforehand, then multimodal tests of sensory and motor function, especially tests of proprioception, were performed regularly afterward. Two hundred participants undergoing elective gynecological surgery under CSEA reported their experiences of PLS and other symptoms using Likert rating scales.

RESULTS

Prolonged preoperative fasting (odds ratio (OR) 2.34; 95% confidence intervals (CI) 1.21-4.52), and surgical history (OR 2.56; 95% CI 1.16-5.62) predisposed to PLS, but patients with more extensive anesthetic histories may be at lower risk (OR 0.57; 95% CI 0.31-1.08). Furthermore, significant correlations were observed between the recovery from PLS and the perception of joint movement within the deafferented area (R = 0.82, P < .01) and motor functions (R = 0.68). PLS increases the chance of experiencing postoperative fatigue, physical discomfort, and emotional upset.

CONCLUSION

This study is the first to have identified the risk factors for PLS, assessed the relationship between PLS and postoperative sensorimotor impairment, and its influence on postoperative complications.

Major lower limb amputation audit - introduction and implementation of a multimodal perioperative pain management guideline

Lower limb amputation is a frequent surgical intervention. It is well known to be associated with postoperative pain. Optimisation of perioperative pain has been shown to reduce the risk of chronic pain. There are no national guidelines for the perioperative pain management of lower limb amputations. Following a baseline audit, we devised a multimodal perioperative pain management guideline, which included the insertion of a local anaesthetic perineural catheter. All patients undergoing an elective or emergency above, through and below knee amputation were reviewed prior and following the implementation of this guideline. Patient postoperative pain scores and opiate usage were analysed. One hundred and twenty-four patients were reviewed (68 patients prior to the implementation of the guideline and 56 patients following the guideline introduction). Following the implementation of the guideline, a greater proportion of patient's pain scores were reported as 0 (i.e. no pain) compared to patients prior to its implementation (78% vs 61%). Pain scores were lower at all time intervals 6 days postoperatively following the guideline introduction. Statistically significant (Kendall's tau-b analysis) (p < 0.05) reduction in pain scores was found upon admission to the ward, 6, 12, 24 hours and 2 days postoperatively. Fewer patients required the use of opioid patient controlled of analgesia after the guideline was introduced (26% vs 4%). The implementation of a perioperative pain management guideline improved pain scores and reduced opioid consumption in patients undergoing lower limb amputations. We suggest a holistic and collaborative, multimodal pathway towards the perioperative pain management of lower limb amputations.

Spinal or general anaesthesia for lower-limb amputation in peripheral artery disease - a retrospective cohort study

BACKGROUND

The present study aimed to determine which method of anaesthesia (spinal anaesthesia or general anaesthesia) is better in reducing post-operative analgesic requirements in patients undergoing major limb amputation for lower-limb ischaemia. Another aim was to find out if anaesthesiologists use neuraxial anaesthesia in high-risk patients despite abnormal coagulation profile or use of anticoagulation.

METHODS

The study was a retrospective cohort study. All patients undergone above-the-knee amputation or below-the-knee amputation due to peripheral artery disease between 1996 and 2010 were reviewed to evaluate post-operative opioid consumption and complications.

RESULTS

A total of 434 amputations in 323 patients were included in the study. The number of surgical complications, the need for surgical revision and the number of intensive care unit admissions were significantly higher in the general anaesthesia group. The need for post-operative opioid medication was significantly lower in patients with above-the-knee amputation and spinal anaesthesia. The use of post-operative epidural analgesia did not reduce analgesic requirements. In the present study, there were patients who received neuraxial anaesthesia despite abnormal coagulation profile or uninterrupted warfarin or clopidogrel. There were no reported cases of spinal or epidural haematoma.

CONCLUSION

Patients with spinal anaesthesia had a lower rate of surgical complications, re-operations and intensive care unit admissions. Patients with above-the-knee amputation and spinal anaesthesia had a lesser need for opioid medication in the post-operative period than patients with general anaesthesia. Anaesthesiologists performed neuraxial anaesthesia and/or analgesia in high-risk patients despite abnormal coagulation profile or ongoing anticoagulation, but no adverse outcomes were reported.

Strategies for prevention of lower limb post-amputation pain: A clinical narrative review

Postamputation limb pain or phantom limb pain (PLP) develops due to the complex interplay of peripheral and central sensitization. The pain mechanisms are different during the initial phase following amputation as compared with the chronic PLP. The literature describes extensively about the management of established PLP, which may not be applicable as a preventive strategy for PLP. The novelty of the current narrative review is that it focuses on the preventive strategies of PLP. The institution of preoperative epidural catheter prior to amputation and its continuation in the immediate postoperative period reduced perioperative opioid consumption (Level II). Optimized preoperative epidural or intravenous patient-controlled analgesia starting 48 hours and continuing for 48 hours postoperatively decreased PLP at 6 months (Level II). Preventive role of epidural LA with ketamine (Level II) reduced persistent pain at 1 year and LA with calcitonin decreased PLP at 12 months (Level II). Peripheral nerve catheters have opioid sparing effect in the immediate postoperative period in postamputation patients (Level I), but evidence is low for the prevention of PLP (Level III). Gabapentin did not reduce the incidence or intensity of postamputation pain (Level II). The review in related context mentions evidence regarding therapeutic role of gabapentanoids, peripheral nerve catheters, and psychological therapy in established PLP. In future, randomized controlled trials with long-term follow-up of patients receiving epidural analgesia, perioperative peripheral nerve catheters, oral gabapentanoids, IV ketamine, or mechanism-based modality for prevention of PLP as primary outcome are required.

Chronic post-amputation pain: peri-operative management - Review

Study design

Narrative review.

Method

Eight bibliographic databases were searched for studies published in the (last five years up until Feb 2017). For the two database searches (Cochrane and DARE), the time frame was unlimited. The review involved keyword searches of the term 'Amputation' AND 'chronic pain'. Studies selected were interrogated for any association between peri-operative factors and the occurrence of chronic post amputation pain (CPAP).

Results

Heterogeneity of study populations and outcome measures prevented a systematic review and hence a narrative synthesis of results was undertaken. The presence of variation in two gene alleles (GCH1 and KCNS1) may be relevant for development of CPAP. There was little evidence to draw conclusions on the association between age, gender and CPAP. Pre-operative anxiety and depression influenced pain intensity post operatively and long-term post amputation pain (CPAP). The presence of pre-amputation pain is correlated to the development of acute and chronic post amputation pain while evidence for the association of post-operative pain with CPAP is modest. Regional anaesthesia and peri-neural catheters improve acute postoperative pain relief but evidence on their efficacy to prevent CPAP is limited. A suggested whole system pathway based on current evidence to optimize peri-operative amputation pain is described.

Conclusion

The current evidence suggests that optimized peri-operative analgesia reduces the incidence of acute peri-operative pain but no firm conclusion can be drawn on reducing risk for CPAP.

Perioperative Pain Management Strategies for Amputation: A Topical Review

Objective

To review acute pain management strategies in patients undergoing amputation with consideration of preoperative patient factors, pharmacologic/interventional modalities, and multidisciplinary care models to alleviate suffering in the immediate post-amputation setting.

Background

Regardless of surgical indication, patients undergoing amputation suffer from significant residual limb pain and phantom limb pain in the acute postoperative phase. Most studies have primarily focused on strategies to prevent persistent pain with inclusion of immediate postoperative outcomes as secondary measures. Pharmacologic agents, including gabapentin, ketamine, and calcitonin, and interventional modalities such as neuraxial and perineural catheters, have been examined in the perioperative period.

Design

Focused Literature Review.

Results

Pharmacologic agents (gabapentin, ketamine, calcitonin) have not shown consistent efficacy. Neuraxial analgesia has demonstrated both an opioid sparing and analgesic benefit while results have been mixed regarding perineural catheters in the immediate post-amputation setting. However, several early studies of perineural catheters employed sub-optimal techniques (distal surgical placement), and prolonged use of perineural catheters may provide a sustained benefit. Regardless of analgesic technique, a multidisciplinary approach is necessary for optimal care.

Conclusion

Patient-tailored analgesic regimens utilizing catheter-based techniques are essential in the acute post-amputation phase and should be implemented in all patients undergoing amputation. Future research should focus on improved measurement of acute pain and comparisons of effective analgesic regimens instead of single techniques.

The pre-amputation pain and the postoperative deafferentation are the risk factors of phantom limb pain: a clinical survey in a sample of Chinese population

BACKGROUND

To provide an overview of phantom limb pain (PLP) in China. This includes the prevalence of PLP and possible risk factors.

METHODS

In a retrospective study, telephone interviews were conducted with 391 amputation patients who underwent extremity amputations at a tertiary hospital in China.

RESULTS

PLP was found in 29% of the amputees. Pre-amputation pain (OR = 10.4, P = 0.002) and postoperative analgesia (OR = 4.9, P = 0.008) were identified as high-risk factors for PLP. 82.1% of PLP patients experienced pre-amputation pain. The average pain intensity of PLP was 5.1 ± 2.2, with 31.9% having severe intensity. The effects of PLP on the quality of the PLP patients were as follows: 7.8% of the patients had to limit their daily life and 29.0% of the patients had to limit their social activities. 17.3 and 25.7% of patients experienced depression and sleeping disorder respectively, while 18.9% had loss of interest and even 16.1% of PLP patients had attempted suicide. No effective treatments were found in 78.9% of these patients.

CONCLUSIONS

PLP has markedly affected the lives of patients. Pre-amputation pain and postoperative epidural analgesia might be risk factors for the phantom limb pain after amputation. Prevention of pre-amputation pain and sudden post-amputation deafferentation should be recommended to the amputees.

Prevalence of Phantom Limb Pain, Stump Pain, and Phantom Limb Sensation among the Amputated Cancer Patients in India: A Prospective, Observational Study

INTRODUCTION

The phantom limb pain (PLP) and phantom limb sensation (PLS) are very common among amputated cancer patients, and they lead to considerable morbidity. In spite of this, there is a lack of epidemiological data of this phenomenon among the Asian population. This study was done to provide the data from Indian population.

METHODS

The prevalence of PLP, stump pain (SP), and PLS was prospectively analyzed from the amputated cancer patients over a period of 2 years in Dr. B.R.A. Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi. The risk factors and the impact of phantom phenomenon on patients were also noted.

RESULTS

The prevalence of PLP was 41% at 3 and 12 months and 45.3% at 6 months, whereas that of SP and PLS was 14.4% and 71.2% at 3 months, 18.75% and 37.1% at 6 months, 15.8% and 32.4% at 12 months, respectively. There was higher prevalence of PLP and PLS among the patients with history of preamputation pain, smoking with proximal level of amputation, receiving general anesthesia, receiving intravenous (IV) opioid postoperative analgesia, and developing neuroma or infection.

CONCLUSION

The prevalence of PLP and PLS was higher among the cancer amputees as compared to SP, and a few risk factors responsible for their higher prevalence were found in our study. The PLP and PLS lead to considerable morbidity in terms of sleep disturbance and depression.

Regional anesthesia for vascular surgery

Patients presenting for vascular surgery present a challenge to anesthesiologists because of their severe systemic comorbidities. Regional anesthesia has been used as a primary anesthetic technique for many vascular procedures to avoid the cardiovascular and pulmonary perturbations associated with general anesthesia. In this article the use of regional anesthesia for carotid endarterectomy, open and endovascular abdominal aortic aneurysm repair, infrainguinal arterial bypass, lower extremity amputation, and arteriovenous fistula formation is described. A focus is placed on reviewing the literature comparing anesthetic techniques, with brief descriptions of the techniques themselves.

A retrospective trial comparing the effects of different anesthetic techniques on phantom pain after lower limb amputation

BACKGROUND

Pain and other sensations from an amputated or absent limb, called phantom pain and phantom sensations, are well-known phenomena.

OBJECTIVE

The aim of this retrospective study was to evaluate the effects of anesthetic techniques on phantom pain, phantom sensations, and stump pain after lower limb amputation.

METHODS

Ninety-two patients with American Society of Anesthesiologists physical status I to III were analyzed for 1 to 24 months after lower limb amputation in this retrospective study. Patients received general, spinal, or epidural anesthesia or peripheral nerve block for their amputations. Standardized questions were used to assess phantom limb pain, phantom sensation, and stump pain postoperatively. Pain intensity was assessed on a numeric rating scale (NRS) of 0 to 10. Patients' medical histories were determined from hospital records.

RESULTS

Patients who received epidural anesthesia and peripheral nerve block perceived significantly less pain in the week after surgery compared with patients who received general anesthesia and spinal anesthesia (NRS [SD] values, 2.68 [1.0] and 2.70 [1.0], respectively). After approximately 14 to 17 months, there was no difference in phantom limb pain, phantom sensation, or stump pain among the anesthetic techniques for amputation.

CONCLUSIONS

In patients undergoing lower limb amputation, performing epidural anesthesia or peripheral nerve block, instead of general anesthesia or spinal anesthesia, might attenuate phantom and stump pain in the first week after operation. Anesthetic technique might not have an effect on phantom limb pain, phantom sensation, or stump pain at 14 to 17 months after lower limb amputation.

Effects of anesthesia versus regional nerve block on major leg amputation mortality rate

There are greater than 120,000 above-knee amputations (AKA) and below-knee amputations (BKA) performed in the USA each year. Traditionally, general anesthesia (GA) was the preferred modality of anesthesia. The use of regional nerve blocks has recently gained popularity, however, without the supporting evidence of any mortality benefits. Our objective was to evaluate whether regional nerve blocks yield significant mortality reduction in major lower-extremity amputations. Retrospective data of both AKA and BKA procedures at the Maimonides Medical Center from 2005 to 2009 were analyzed. Patients received either general sedation, spinal or ultrasound-guided regional nerve blocks as per decision of the attending anesthesiologist. Regional nerve blocks for major lower-extremity amputations consisted of femoral, sciatic, saphenous and popliteal nerve blocks. A retrospective inquiry of 30-day mortality was performed with reference to the Social Security Death Index and hospital records. One hundred and fifty-eight patients were included in the study (82 men and 86 women with mean age of 74.5 years ± 12.9 SD, range of 33-98 years) of which 46 patients had regional nerve blocks and 112 had GA or spinal blocks. Patients who received both regional blocks and GA/spinal blocks within 30 days were excluded. The overall 30-day mortality was 17.1% (27 patients) consisting of 15.2% for regional nerve analgesia versus 17.9% for GA/spinal blocks ( P = 0.867). Age did not affect mortality outcome in either groups of anesthesia modality. Our analysis did not reveal any mortality benefit of utilizing regional nerve block over GA or spinal blocks.

High-dose remifentanil prevents development of thermal hyperalgesia in a neuropathic pain model

BACKGROUND

Intraoperative nerve lesions can lead to chronic postoperative pain. There are conflicting data as to whether or not anaesthetics administered intraoperatively are beneficial. We investigated if remifentanil administered at the time of nerve injury was able to attenuate neuropathic hypersensitivity.

METHODS

Rats were anaesthetized with isoflurane, endotracheally intubated, and a tail vein catheter was inserted. Rats received an i.v. infusion of either saline or low- or high-dose remifentanil (2 or 20 μg kg(-1) min(-1), respectively) for 20 min. During this time, rats received a spinal nerve L5 transection to induce neuropathic pain or a sham procedure. Behavioural tests to assess mechanical and cold allodynia and heat hyperalgesia were performed on postoperative days 1, 3, 7, 14, 21, and 28.

RESULTS

Sham-operated animals exhibited no hypersensitivity regardless of the intraoperative remifentanil dose. In rats which received spinal nerve L5 transection, mechanical and cold allodynia developed with no significant differences between treatment groups. However, thermal hyperalgesia was reduced in rats given high-dose remifentanil: mean (standard deviation) area under the curve 426 (53) compared with 363 (34) and 342 (24) in saline or low-dose remifentanil treated rats, respectively (P<0.05).

CONCLUSIONS

High-dose remifentanil administered at the time of transection of the spinal nerve at L5 prevents subsequent thermal hyperalgesia.

Preventing Chronic Pain following Acute Pain: Risk Factors, Preventive Strategies, and their Efficacy

Chronic pain is the leading cause of disability in the United States. The transition from acute to persistent pain is thought to arise from maladaptive neuroplastic mechanisms involving three intertwined processes, peripheral sensitization, central sensitization, and descending modulation. Strategies aimed at preventing persistent pain may target such processes. Models for studying preventive strategies include persistent post-surgical pain (PPP), persistent post-trauma pain (PTP) and post-herpetic neuralgia (PHN). Such entities allow a more defined acute onset of tissue injury after which study of the long-term effects is more easily examined. In this review, we examine the pathophysiology, epidemiology, risk factors, and treatment strategies for the prevention of chronic pain using these models. Both pharmacological and interventional approaches are described, as well as a discussion of preventive strategies on the horizon.

An enhanced bunionectomy model as a potential tool for early decision-making in the development of new analgesics

BACKGROUND

bunionectomy has been used as a model of postoperative pain for opioids and nonsteroidal anti-inflammatory drugs/cyclooxygenase-2 inhibitors with a fast onset of analgesia. The present study was conducted to assess whether the utility of the model can be broadened in assessing the efficacy of analgesics with diverse mechanisms and pharmacokinetic profiles in drug development and to enhance the sensitivity of a bunionectomy model.

METHODS

this was a single center, randomized, double-blind, placebo-controlled, three-arm, parallel group methodology study to evaluate the effects of pregabalin and naproxen sodium on postoperative pain following bunionectomy. Patients (n=100) were randomized 1:1:1 to three treatments (administered 1 hour before and at defined intervals after surgery): pregabalin 300 mg before surgery and 150 mg every 8 hours; naproxen sodium 550 mg before surgery and 550 mg every 12 hours; or placebo in a double-dummy fashion. Primary endpoints were patient-controlled analgesic (PCA) hydromorphone consumption and the time to first PCA hydromorphone use postsurgery over 24 hours.

RESULTS

of the 100 patients randomized, 96 completed the study. Relative to placebo, pregabalin and naproxen sodium, respectively, reduced PCA hydromorphone consumption by 51% (P=0.005) and 65% (P<0.001) and increased the median time to first use of PCA hydromorphone by 1.5 hours (P=0.004) and 3.7 hours (P<0.001). Both drugs significantly (P<0.050) decreased use of oral opioid rescue medication over 24-48 hours postsurgery relative to placebo. Although there were no statistically significant differences between naproxen sodium and pregabalin in opioid consumption and global evaluation of medication, overall naproxen sodium appeared to be more effective at reducing pain.

CONCLUSIONS

the model provided a sensitive method for evaluating efficacy of compounds with diverse mechanisms and pharmacokinetic profiles. The robustness of the enhanced pain model renders bunionectomy pain a valuable tool to assess novel analgesic compounds in small numbers of subjects early in drug development.

Evolving techniques in foot and ankle amputation

Multiple clinical pathways lead to lower extremity amputation, including trauma, dysvascular disease, congenital defects, and malignancy. However, the principles of successful amputation-careful preoperative planning, coordination of a multidisciplinary team, and good surgical technique-remain the same. Organized rehabilitation and properly selected prostheses are integral components of amputee care. In the civilian setting, amputation is usually performed as a planned therapy for an unsalvageable extremity, not as an emergency procedure. The partial loss of a lower limb often represents a major change in a person's life, but patients should be encouraged to approach amputation as the beginning of a new phase of life and not as the culmination of previous treatment failures.

Preoperative opioid consumption increases morphine requirement after leg amputation

PURPOSE

The aim of this observational study was to assess the influence of preoperative opioid consumption on postoperative morphine consumption after leg amputation performed under combined regional and general anesthesia.

METHODS

After Institutional Review Board approval, patients scheduled for leg amputation were included in a prospective observational study. A popliteal sciatic nerve catheter was placed preoperatively and 0.75% ropivacaine 20 mL was injected incrementally. Amputation was performed under general anesthesia. Postoperative analgesia included acetaminophen, a continuous infusion of 0.2% ropivacaine at 7 mL hr(-1), and intravenous morphine if the visual analogue scale (VAS) pain score was >3 on a 0-10 scale. Patients were divided post-hoc into two groups according to their preoperative opioid consumption: yes (Preop opioids) or no (No preop opioid).

RESULTS

Twenty-two patients were included, 12 in the Preop opioids Group and 10 in the No preop opioid Group. The VAS score after catheter insertion and before induction of general anesthesia was zero in both groups. Total postoperative opioid consumption from day 1 to day 3 and daily consumption at day 7 was greater in the Preop opioids Group than in the No preop opioid Group (52 [13-133] mg morphine equivalents vs 0 [0-26] mg; P = 0.02) and (10 [8-25] mg vs 0 [0-0] mg; P = 0.01), respectively, (median [25-75 interquartile values]).

CONCLUSION

Despite the use of regional anesthesia, chronic opioid consumption before leg amputation is associated with increased postoperative morphine consumption and phantom limb pain.

Neuropathic pain in dogs and cats: if only they could tell us if they hurt

Neuropathic pain is difficult to diagnose in veterinary patients because they are unable to verbalize their pain. By assuming that neuropathic pain may exist based on the history of events that each patient has experienced, a focused client history and neurologic examination may identify a lesion resulting in persistent or spontaneous pain. Once neuropathic pain is diagnosed, a trial analgesic or acupuncture session(s) should be prescribed with instructions for owners to observe behavior. Dosing of the analgesic can be titrated to the patient's needs while avoiding adverse effects. When a particular analgesic may be ineffectual, an alternate class should be tried. As research into the neurobiologic mechanisms of neuropathic pain continues, specific therapies for its management should eventually appear in the human clinical setting and subsequently be investigated for veterinary clinical use.

Osteoporosis: A factor on residual limb pain in traumatic trans-tibial amputations

Residual limb pain is defined as a painful sensation or feeling from the remaining part of the leg. Aggressive bone edge, bone spur formation, neuroma, abscess or bursitis are common causes of residual limb pain. On the other hand, regional osteoporosis on femur and tibia is an inevitable consequence in patients with lower limb amputations. The etiology of bone loss is uncertain but it is likely to be a local phenomenon in lower limb amputees. Altered gait pattern, decreased weight load, disuse atrophy and lack of muscular action at the limb seem to be important causal factors in the development of both local and generalized osteoporosis. The aims of this study are: (i) To determine if there is significant bone mineral density (BMD) difference at proximal tibias and femurs between intact and amputated limbs, (ii) to investigate the factors affecting bone loss in these areas and (iii) to investigate the possible relationship between residual limb pain and local bone loss. The 36 men who participated in this study had amputations due to land-mine injuries. Dual energy X-ray absorptiometry was used to determine BMD of the proximal femur and proximal tibia. The non-amputated limb was used as a control for the amputated side. BMD values on the amputated side were significantly lower than non-amputated side. In addition, BMD values on the amputated limbs with residual limb pain were significantly less than in those without residual limb pain. Insufficient mechanical loading leads to bone loss in patients with trans-tibial amputations. Furthermore, bone loss at tibia may be a cause of residual limb pain. However, this needs to be confirmed with more specific studies in the future.

Pain management in the traumatic amputee

Traumatic amputees may experience a variety of acute and chronic pain issues, including phantom limb pain and residual limb pain. Research continues to determine the causes of these problems and to find the most appropriate and effective treatments for each of these phenomena. It is important for health care providers to be knowledgeable about the variety of treatments available, including medications, surgical procedures, complementary and alternative therapies, and self-treatment methods to ensure that amputees receive the best practices for individualized, effective pain management that they deserve.