Efficacy of Thoracic Epidural Analgesia With or Without Intercostal Nerve Cryoanalgesia for Postthoracotomy Pain

A randomized study of cryoablation of intercostal nerves in patients undergoing minimally invasive thoracic surgery

OBJECTIVES

Minimally invasive thoracic surgery can cause significant pain, and optimizing pain control after surgery is highly desirable. We examined pain control after intercostal nerve block with or without cryoablation of the intercostal nerves.

METHODS

This was a randomized study (NCT05348447) of adults scheduled for a minimally invasive thoracic procedure. Each intercostal space near the incision site was injected with lidocaine and bupivacaine with epinephrine (standard of care). The cryoanalgesia group also had 5 to 6 intercostal nerves ablated. The primary outcome was the amount of narcotics (in morphine milligram equivalents taken during the postoperative hospital stay and the first 2 weeks postdischarge. Secondary outcomes were incentive spirometry volume and pain scores in the hospital and pain and neuropathy scores at 2 weeks.

RESULTS

Our final cohort contained 103 patients (52 standard of care and 51 cryoanalgesia). There were no differences between the treatment groups in morphine milligram equivalents administered during the hospital stay (44.9 vs 38.4 mg), total morphine milligram equivalents at 2 weeks (108.8 vs 95.2 mg), or pain assessed by visual analog scale on postoperative day 1 (3.8 and 3.3), postoperative day 2 (2 and 3.5), or 2 weeks (2 and 3.5) for standard of care and cryoanalgesia group patients, respectively. The decrease in incentive spirometry during the postoperative period was not significantly different between the 2 groups. Patients in the cryoanalgesia group had higher neuropathy scores (8 vs 13; P = .019) 2 weeks after surgery.

CONCLUSIONS

In this randomized study, cryoanalgesia did not decrease postoperative pain or narcotic requirements. Cryoanalgesia increased neuropathic pain 2 weeks after surgery.

A Narrative Review of Ultrasound-Guided and Landmark-based Percutaneous Cryoneurolysis for the Management of Acute and Chronic Pain

PURPOSE OF REVIEW

Cryoneurolysis refers to the process of reversibly ablating peripheral nerves with extremely cold temperatures to provide analgesia for weeks to months. With ultrasound-guidance or landmark-based techniques, it is an effective modality for managing both acute and chronic pain. In this review, we summarize the reported literature behind its potential applications and efficacy.

RECENT FINDINGS

Here, we summarize several studies (from case reports to clinical trials) describing the use of ultrasound-guided and landmark-based cryoneurolysis for acute and chronic pain. Acute pain indications included pain related to knee arthroplasty, limb amputations, mastectomies, shoulder surgery, rib fractures, and burn. Chronic pain indications included chronic knee pain (due to osteoarthritis), shoulder pain, painful neuropathies, postmastectomy pain syndrome, phantom limb pain, facial pain/headaches, foot/ankle pain, inguinal pain, and sacroiliac joint pain. For both acute and chronic pain indications, more high quality randomized controlled clinical trials are needed to definitively assess the efficacy of cryoneurolysis versus other standard therapies for a multitude of pain conditions.

Cryoanalgesia: Review with Respect to Peripheral Nerve

BACKGROUND

 Cryoanalgesia is a tool being used by interventional radiology to treat chronic pain. Within a certain cold temperature range, peripheral nerve function is interrupted and recovers, without neuroma formation. Cryoanalgesia has most often been applied to the intercostal nerve. Cryoanalgesia has applications to peripheral nerve surgery, yet is poorly understood by reconstructive microsurgeons.

METHODS

 Histopathology of nerve injury was reviewed to understand cold applied to peripheral nerve. Literature review was performed utilizing the PubMed and MEDLINE databases to identify comparative studies of the efficacy of intraoperative cryoanalgesia versus thoracic epidural anesthesia following thoracotomy. Data were analyzed using Fisher's exact and analysis of variance tests. A similar approach was used for pudendal cryoanalgesia.

RESULTS

 Application of inclusion and exclusion criteria resulted in 16 comparative clinical studies of intercostal nerve for this review. For thoracotomy, nine studies compared cryoanalgesia with pharmaceutical analgesia, with seven demonstrating significant reduction in postoperative opioid use or postoperative acute pain scores. In these nine studies, there was no association between the number of nerves treated and the reduction in acute postoperative pain. One study compared cryoanalgesia with local anesthetic and demonstrated a significant reduction in acute pain with cryoanalgesia. Three studies compared cryoanalgesia with epidural analgesia and demonstrated no significant difference in postoperative pain or postoperative opioid use. Interventional radiology targets pudendal nerves using computed tomography imaging with positive outcomes for the patient with pain of pudendal nerve origin.

CONCLUSION

 Cryoanalgesia is a term used for the treatment of peripheral nerve problems that would benefit from a proverbial reset of peripheral nerve function. It does not ablate the nerve. Intraoperative cryoanalgesia to intercostal nerves is a safe and effective means of postoperative analgesia following thoracotomy. For pudendal nerve injury, where an intrapelvic surgical approach may be difficult, cryoanalgesia may provide sufficient clinical relief, thereby preserving pudendal nerve function.

Combined erector spinae plane block with surgical intercostal nerve cryoablation for Nuss procedure is associated with decreased opioid use and length of stay

BACKGROUND AND OBJECTIVES

Pain management for patients undergoing the Nuss procedure for treatment of pectus excavatum can be challenging. In an effort to improve pain management, our institution added bilateral single injection erector spinae plane (ESP) blocks to surgeon placed intercostal nerve cryoablation. We aimed to assess the efficacy of this practice change.

METHODS

Retrospective clinical data from a single academic medical center were evaluated. Due to an institutional change in clinical management, we were able to perform a before and after study. Twenty patients undergoing Nuss procedure who received bilateral ultrasound-guided single-shot T6 level ESP blocks and intercostal nerve cryoablation were compared with a historical control cohort of 20 patients who underwent Nuss procedure with intercostal nerve cryoablation alone. The primary outcome variables included postoperative pain scores, total hospital opioid use, and hospital length of stay.

RESULTS

Median total hospital intravenous morphine milligram equivalents was lower for the ESP group than for the control group (0.60 (IQR 0.35-0.88) vs 1.15 mg/kg (IQR 0.74-1.68), p<0.01). There was no difference in postoperative pain scores between the two groups. Mean hospital length of stay was 2.45 (SD 0.69) days for the control group and 1.95 (SD 0.69) days for the ESP group (p=0.03). No adverse events related to block placement were identified.

CONCLUSIONS

In a single-center academic practice, the addition of bilateral single injection ESP blocks at T6 to surgeon performed cryoablation reduced opioid consumption without a change in subjectively reported pain scores. The results from this pilot study can provide effect size estimates to guide the design of future randomized trials.

A Prospective Study of Sensory Changes in Pediatric Patients After Minimally Invasive Repair of Pectus Excavatum With Cryoablation

BACKGROUND

Cryoablation during minimally invasive repair for pectus excavatum (MIRPE) reduces opioid use and hospital length of stay. Skin hypoesthesia of the chest wall also occurs. This study sought to determine the frequency, onset, duration, and location of sensory changes and neuropathic pain after cryoablation.

METHODS

A prospective study was conducted on patients aged ≤21 years undergoing MIRPE with cryoablation of T3 to T7 dermatomes bilaterally for 120 s at a single institution between March 2021 to December 2022. Patients underwent sensory testing of the chest wall and neuropathic pain surveys (S-LANSS) preoperatively and then postoperatively for 6 months. Incidence and duration of hypoesthesia and neuropathic pain were evaluated.

RESULTS

Of 61 patients enrolled in the study, 45 completed evaluations at six months postoperatively. All patients had skin hypoesthesia on postoperative day (POD)1. The mean percentage of the treated anterior chest wall surface area (TACWSA) with hypoesthesia to cold stimulus was 52% (±29.3) on POD 0 and 55% (±19.7) on POD 1. Sensation returned over time, with hypoesthesia affecting 11.1% (±15.5) TACWSA at 6 months. At study completion 58% of patients (26/45) had complete return of sensation; hypoesthesia was found at: 1 dermatome 13% (2/45), 2 dermatomes 22% (11/45), and 3 dermatomes 4% (2/45). Neuropathic pain (S-LANSS ≥12) was documented in 16% (9/55) of patients at hospital discharge but decreased to 6.7% of patients at 6 months.

CONCLUSION

Onset of skin hypoesthesia after cryoablation occurred on POD0 and affected 52% of the TACWSA. All patients experienced return of sensation to varying degrees, with 58% experiencing normal sensation in all dermatomes by 6 months. The etiology of persistent hypoesthesia to select dermatomes is unknown but may be related to operative technique or cryoablation. Chronic neuropathic pain is uncommon.

LEVEL OF EVIDENCE

II.

TYPE OF STUDY

Prognosis Study.

Intercostal Nerve Cryoablation for Postoperative Pain Control in Pediatric Thoracic Surgery: A Scoping Review

Background: Cryoanalgesia uses the application of cold temperatures to temporarily disrupt peripheral sensory nerve function for pain control. This review outlines the principles of cryoablation, clinical applications, and clinical data for its use in pediatric thoracic surgery. Methods: A comprehensive PubMed search was performed using the principal terms and combinations of cryoablation, cryoanalgesia, Nuss, Nuss repair, pectus, pectus excavatum, thoracic surgery, thoracotomy, and chest wall. Pediatric articles were reviewed and included if relevant. Adult articles were reviewed for supporting information as needed. Reference lists of included articles were reviewed for possible additional sources. Discussion: The scientific and clinical principles of cryoablation are outlined, followed by a focused review of current clinical application and outcome data. Conclusion: Postoperative pain is a major challenge following thoracic surgery. Cryoanalgesia is emerging as an adjunct in pediatric thoracic surgery, particularly for the Nuss procedure or minimally invasive repair of pectus excavatum. It effectively controls pain, decreasing postoperative opioid use and hospital length of stay with few short-term complications. Although more long-term studies are needed, early evidence suggests there is reliable return of sensation to the chest wall and long-term neuropathic pain is rare.

Neurolysis for analgesia following pectus repair in a national cohort

INTRODUCTION

Pectus excavatum and pectus carinatum are the most common chest wall deformities of childhood. Surgical repair can be complicated by post-operative analgesic challenges. Thoracic epidural analgesia, patient-controlled analgesia, and multimodal pain control are among the most common strategies. We sought to define the current utilization of intraoperative thoracic neurolysis, hypothesizing that this would minimize length of stay (LOS) and post-operative narcotic use with relatively higher proportion of non-narcotic post-operative analgesia.

METHODS

We performed a retrospective review of the Pediatric Health Information System (PHIS) database between 2017 and 2020. We first identified patients who underwent a pectus repair via ICD-10-PCS codes. We used ICD-10-PCS codes 01580ZZ and 01584ZZ to identify those patients who underwent concomitant thoracic neurolysis. Statistical analyses were performed using R; p value less than 0.05 was considered significant.

RESULTS

We identified 2979 patients who underwent a pectus repair. 184 underwent a concomitant thoracic nerve destruction procedure (6.7%); 13 were performed in 2017 (2.01%), 76 in 2018 (10.7%), and 84 in 2019 (9.6%). LOS was shorter in those patients who underwent neurolysis (mean=2.55 vs 3.73 days, SD=1.33 vs 1.78 days, p<0.001). There were fewer post-operative ICU admissions in neurolysis patients (3/184 vs. 193/2795, p = 0.003). The cost of procedures that included a neurolysis were higher, though not significantly so (mean=$24,885.64 vs $22,200.59).

CONCLUSION

Thoracic neurolysis may be a useful analgesic strategy, expediating post-operative discharge and potentially obviating the need for intensive care. Further larger-scale prospective trials should be considered to further elucidate the role of this analgesia method.

LEVEL OF EVIDENCE

Level III.

Extending Perioperative Analgesia with Ultrasound-Guided, Percutaneous Cryoneurolysis, and Peripheral Nerve Stimulation (Neuromodulation)

The use of regional anesthesia is key to a successful approach to improving postoperative analgesia, which involves local anesthetic deposition either around peripheral nerves or within a fascial plane. Unfortunately, the realistic duration even with continuous peripheral nerve blocks usually does not match the duration of surgical pain, comprising a major limitation. Here, the use of 2 interventional modalities-ultrasound-guided percutaneous cryoneurolysis and peripheral nerve stimulation-is discussed, both of which may be used to treat acute and subacute pain and may therefore have a positive impact on the incidence and severity of chronic pain development.

Ultrasound-guided erector spinae plane block versus thoracic epidural analgesia: Postoperative pain management after Nuss repair for pectus excavatum

AIM OF THE STUDY

Postoperative pain management is a significant challenge in patients undergoing Nuss repair for pectus excavatum chest wall deformity. Therapeutic anesthetic options primarily include patient-controlled intravenous analgesia, thoracic epidural analgesia (TEA), and cryoanalgesia. However, TEA is limited to inpatient use and both TEA and cryoanalgesia can result in neurologic injury. The novel technique of ultrasound-guided erector spinae plane regional analgesia has been used recently in our patients undergoing the Nuss repair and has shown impressive pain relief, but without the potential complications of other modalities. Erector spinae plane block (ESPB) postoperative pain management outcomes were studied as compared to TEA.

METHODS

Thirty consecutive patients with severe pectus excavatum undergoing Nuss repair and placement of ultrasound-guided ESPB were each paired to a historical cohort control patient with TEA postoperative pain management. The cohort patient match was defined by age (± 2 years), gender, and CT pectus index (± 15%). Study variables included hospital length of stay (LOS), pain scores, and pain medication usage.

RESULTS

Pain scores as measured by area under the curve per hour (Day 1: 2.72 (SD = 1.37) vs. 3.90 (SD = 1.81), P = 0.006; Day 2: 2.83 (SD = 1.32) vs. 3.97 (SD = 1.82), P = 0.007) and oral morphine equivalent (OME) pain medication usage (Day 1: 11.9 (SD = 4.9) vs 56.0 (SD = 32.2), P < 0.001; Day 2: 14.7 (SD = 7.1) vs. 38.0 (SD = 21.7), P < 0.001) were higher for the first two postoperative days in the ESPB group. However, mean hospital LOS was nearly one day shorter for ESPB patients (3.78 (SD = 0.82) vs. 2.90 (SD = 0.87), P < 0.001) who were discharged home with the catheter in place until removal, typically at 5-7 days postoperatively.

CONCLUSION

Ultrasound-guided ESPB is thus a feasible, safe, and effective alternative to TEA in postoperative pain management after Nuss repair and results in decreased hospital stay.

LEVEL OF EVIDENCE

III.

Post-thoracotomy analgesia

Thoracotomy is considered one of the most painful operative procedures. Due to anatomical complexity, post-thoracotomy pain requires multimodal perioperative treatment to adequately manage to ensure proper postoperative recovery. There are several different strategies to control post-thoracotomy pain including interventional techniques, such as neuraxial and regional injections, and conservative treatments including medications, massage therapy, respiratory therapy, and physical therapy. This article describes different strategies and evidence base for their use.

Cryoanalgesia for postsurgical pain relief in adults: A systematic review and meta-analysis

Background

Despite advances in pain management, postoperative pain continues to be an important problem with significant burden. Many current therapies have dose-limiting adverse effects and are limited by their short duration of action. This review examines the evidence for the efficacy and safety of cryoanalgesia in postoperative pain.

Materials and methods

This review was registered in PROSPERO and prepared in accordance with PRISMA. MEDLINE, EMBASE, and Cochrane databases were searched until July 2020. We included randomized controlled trials (RCTs) of adults evaluating perioperatively administered cryoanalgesia for postoperative pain relief.

Results

Twenty-four RCTS were included. Twenty studies examined cryoanalgesia for thoracotomy, two for herniorrhaphy, one for nephrectomy and one for tonsillectomy. Meta-analysis was performed for thoracic studies. We found that cryoanalgesia with opioids was more efficacious than opioid analgesia alone for acute pain (mean difference [MD] 2.32 units, 95 % confidence interval [CI] -3.35 to -1.30) and persistent pain (MD 0.81 units, 95 % CI -1.10 to -0.53) after thoracotomy. Cryoanalgesia with opioids also resulted in less postoperative nausea compared to opioid analgesia alone (relative risk [RR] 0.23, 95 % CI 0.06 to 0.95), but there was no difference in atelectasis (RR 0.38, 95 % CI 0.07 to 2.17).

Conclusion

Heterogeneity in comparators and outcomes were important limitations. In general, reporting of adverse events was incomplete and inconsistent. Many studies were over two decades old, and most were limited in how they described their methodology. Considering the potential, larger RCTs should be performed to better understand the role of cryoanalgesia in postoperative pain management.

Percutaneous cryoneurolysis for acute pain management: current status and future prospects

Introduction: Conventional nerve blocks utilize local anesthetic drugs to provide pain relief for hours or days following surgery or trauma. However, postoperative and trauma pain can last weeks or months. Ultrasound-guided percutaneous cryoneurolysis is an anesthetic modality that offers substantially longer pain relief compared to local anesthetic-based nerve blocks.Areas covered: In this review, we discuss the history, mechanism of action, and use of ultrasound-guided percutaneous cryoneurolysis by anesthesiologists in the setting of acute pain management.Expert opinion: Ultrasound-guided percutaneous cryoneurolysis offers the potential to provide weeks or months of pain relief following surgery or trauma. Compared to continuous local anesthetic-based peripheral nerve blocks, currently the gold standard for providing long duration postoperative analgesia, cryoneurolysis has benefits that include: 1) longer duration measured in weeks or months rather than days; 2) no external reservoir of local anesthetic to be carried by the patient; 3) no risk of infection; and 4) no risk of catheter dislodgement. However, cryoneurolysis can induce a prolonged motor block in addition to the sensory block, decreasing the appropriate indications to those in which potential sensory and motor deficits are acceptable. Additionally, cryoneurolysis of multiple nerves can have a substantial time requirement relative to conventional nerve blocks.

Cryoneurolysis and Percutaneous Peripheral Nerve Stimulation to Treat Acute Pain

Two regional analgesic modalities currently cleared by the U.S. Food and Drug Administration hold promise to provide postoperative analgesia free of many of the limitations of both opioids and local anesthetic-based techniques. Cryoneurolysis uses exceptionally low temperature to reversibly ablate a peripheral nerve, resulting in temporary analgesia. Where applicable, it offers a unique option given its extended duration of action measured in weeks to months after a single application. Percutaneous peripheral nerve stimulation involves inserting an insulated lead through a needle to lie adjacent to a peripheral nerve. Analgesia is produced by introducing electrical current with an external pulse generator. It is a unique regional analgesic in that it does not induce sensory, motor, or proprioception deficits and is cleared for up to 60 days of use. However, both modalities have limited validation when applied to acute pain, and randomized, controlled trials are required to define both benefits and risks.

Ultrasound-guided percutaneous intercostal cryoanalgesia for multiple weeks of analgesia following mastectomy: a case series

Background

Acute post-mastectomy pain is frequently challenging to adequately treat with local anesthetic-based regional anesthesia techniques due to its relatively long duration measured in multiple weeks.

Case

We report three cases in which preoperative ultrasound-guided percutaneous intercostal nerve cryoneurolysis was performed to treat pain following mastectomy. Across all postoperative days and all three patients, the mean pain score on the numeric rating scale was 0 for each day. Similarly, no patient required any supplemental opioid analgesics during the entire postoperative period; and, no patient reported insomnia or awakenings due to pain at any time point. This was a significant improvement over historic cohorts.

Conclusions

Ultrasound-guided percutaneous cryoanalgesia is a potential novel analgesic modality for acute pain management which has a duration that better-matches mastectomy than other currently-described techniques. Appropriately powered randomized, controlled clinical trials are required to demonstrate and quantify both potential benefits and risks.

Peripheral nerve blocks for postoperative analgesia: From traditional unencapsulated local anesthetic to liposomes, cryoneurolysis and peripheral nerve stimulation

Peripheral nerve blocks (PNBs) using local anesthetics either via single injection or continuous perineural catheter have been the mainstay for regional anesthesia and are a vital component of postoperative multimodal opioid-sparing pain management. There are some limitations to PNBs, however, mainly its limited duration of action, but also risk of catheter-associated infection and dislodgements. Furthermore, local anesthetic-based blocks can induce sensory deficits and motor weakness, possibly increasing the risk of falling and/or decreasing the ability to participate in postoperative rehabilitation. In this review, we first discuss various local anesthetic-based PNB techniques for major surgery and then review newer modalities, including liposome bupivacaine, cryoanalgesia, and peripheral nerve stimulation; all of which may offer advantages over single and continuous local anesthetic-based PNBs.

Novel Methodologies in Regional Anesthesia for Knee Arthroplasty

Maximizing analgesia is critical following joint arthroplasty because postoperative pain is a major barrier to adequate physical therapy. Continuous peripheral nerve blocks have been the mainstay for acute pain management in this population; however, this and similar techniques are limited by their duration of action. Cryoneurolysis and peripheral nerve stimulation are two methodologies used for decades to treat chronic pain. With the advent of portable ultrasound devices and percutaneous administration equipment, both procedures may now be suitable for treatment of acute pain. This article reviews these two modalities and their application to joint arthroplasty.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 39 studies, enrolling a total of 3027 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 41 studies, enrolling a total of 3143 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Intraoperative cryoanalgesia for managing pain after the Nuss procedure

BACKGROUND

Cryoanalgesia prevents pain by freezing the affected peripheral nerve. We report the use of intraoperative cryoanalgesia during the Nuss procedure for pectus excavatum and describe our initial experience, modifications of technique, and lessons learned.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of patients who received cryoanalgesia during the Nuss procedure between June 1, 2015, and April 30, 2016, at our institutions and analyzed modifications in surgical technique during this early adoption period.

RESULTS

Eight male and two female patients underwent the Nuss procedure with cryoanalgesia. The mean postoperative length of stay (LOS) was 2days (range 1-3). Average inpatient pain scores were 3.4, 3.2, and 4.6 on postoperative days 1-3, respectively (N=10, 7, and 2). At a 1-week postoperative visit, mean pain score was 1.1 (N=6). Compared to the preceding 15 Nuss patients at our institution, who were treated with a thoracic epidural, postoperative LOS was significantly shorter with cryoanalgesia (2.0±0.82 vs. 6.3±1.3days, P<0.001). We modified our technique for patient habitus and adopted single-lung ventilation for improved visualization.

CONCLUSIONS

Cryoanalgesia may be the ideal pain management strategy for Nuss patients because it is effective and long lasting. Intraoperative application is easily integrated into the Nuss procedure.

STUDY TYPE

Treatment study: case series; Evidence level IV.

A systematic review of therapeutic interventions to reduce acute and chronic post-surgical pain after amputation, thoracotomy or mastectomy

Background

Perioperative neuropathic pain is under-recognized and often undertreated. Chronic pain may develop after any routine surgery, but it can have a far greater incidence after amputation, thoracotomy or mastectomy. The peak noxious barrage due to the neural trauma associated with these operations may be reduced in the perioperative period with the potential to reduce the risk of chronic pain.

Databases and data treatment

A systematic review of the evidence for perioperative interventions reducing acute and chronic pain associated with amputation, mastectomy or thoracotomy.

Results

Thirty-two randomized controlled trials met the inclusion criteria. Gabapentinoids reduced pain after mastectomy, but a single dose was ineffective for thoracotomy patients who had an epidural. Gabapentinoids were ineffective for vascular amputees with pre-existing chronic pain. Venlafaxine was associated with less chronic pain after mastectomy. Intravenous and topical lidocaine and perioperative EMLA (eutectic mixture of local anaesthetic) cream reduced the incidence of chronic pain after mastectomy, whereas local anaesthetic infiltration appeared ineffective. The majority of the trials investigating regional analgesia found it to be beneficial for chronic symptoms. Ketamine and intercostal cryoanalgesia offered no reduction in chronic pain. Total intravenous anaesthesia (TIVA) reduced the incidence of post-thoracotomy pain in one study, whereas high-dose remifentanil exacerbated chronic pain in another.

Conclusions

Appropriate dose regimes of gabapentinoids, antidepressants, local anaesthetics and regional anaesthesia may potentially reduce the severity of both acute and chronic pain for patients. Ketamine was not effective at reducing chronic pain. Intercostal cryoanalgesia was not effective and has the potential to increase the risk of chronic pain. TIVA may be beneficial but the effects of opioids are unclear.

A comparison of the analgesia efficacy and side effects of paravertebral compared with epidural blockade for thoracotomy: an updated meta-analysis

Objective

The most recent systematic review and meta-analysis comparing the analgesic efficacy and side effects of paravertebral and epidural blockade for thoracotomy was published in 2006. Nine well-designed randomized trials with controversial results have been published since then. The present report constitutes an updated meta-analysis of this issue.

Summary of Background

Thoracotomy is a major surgical procedure and is associated with severe postoperative pain. Epidural analgesia is the gold standard for post-thoracotomy pain management, but has its limitations and contraindications, and paravertebral blockade is increasingly popular. However, it has not been decided whether the analgesic effect of the two methods is comparable, or whether paravertebral blockade leads to a lower incidence of adverse side effects after thoracotomy.

Methods

Two reviewers independently searched the databases PubMed, EMBASE, and the Cochrane Library (last performed on 1 February, 2013) for reports of studies comparing post-thoracotomy epidural analgesia and paravertebral blockade. The same individuals independently extracted data from the appropriate studies.

Result

Eighteen trials involving 777 patients were included in the current analysis. There was no significant difference in pain scores between paravertebral blockade and epidural analgesia at 4–8, 24, 48 hours, and the rates of pulmonary complications and morphine usage during the first 24 hours were also similar. However, paravertebral blockade was better than epidural analgesia in reducing the incidence of urinary retention (p<0.0001), nausea and vomiting (p = 0.01), hypotension (p<0.00001), and rates of failed block were lower in the paravertebral blockade group (p = 0.01).

Conclusions

This meta-analysis showed that PVB can provide comparable pain relief to traditional EPI, and may have a better side-effect profile for pain relief after thoracic surgery. Further high-powered randomized trials are to need to determine whether PVB truly offers any advantages over EPI.

Is cryoanalgesia effective for post-thoracotomy pain?

A best evidence topic was written according to a structured protocol. The question addressed was whether cryoanalgesia improves post-thoracotomy pain and recovery. Twelve articles were identified that provided the best evidence to answer the question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were pain scores, additional opiate requirements, incidence of hypoesthesia and change in lung function. Half of the articles reviewed failed to demonstrate superiority of cryoanalgesia over other pain relief methods; however, additional opiate requirements were reduced in patients receiving cryoanalgesia. Change in lung function postoperatively was equivocal. Cryoanalgesia potentiated the incidence of postoperative neuropathic pain. Further analysis of the source of cryoanalgesia, duration, temperature obtained and extent of blockade revealed numerous discrepancies. Three studies utilized CO2 as the source of cryoanalgesia and four used nitrous oxide, but at differing temperatures and duration. Five studies did not reveal the source of cyroanalgesia. The number of intercostal nerves anaesthetized in each study varied. Seven articles anaesthetized three intercostal nerves, three articles used five intercostal nerves, one article used four intercostal nerves and one used one intercostal nerve at the thoracotomy site. Thoracotomy closure and site of area of chest drain insertion may have a role in postoperative pain; but only one article explained method of closure, and two articles mentioned placement of chest drain through blocked dermatomes. No causal inferences can be made by the above results as they are not directly comparable due to confounding variables between studies. Currently, the evidence does not support the use of cryoanalgesia alone as an effective method for relieving post-thoracotomy pain.

Comparison of non-divided intercostal muscle flap and intercostal nerve cryoanalgesia treatments for post-oesophagectomy neuropathic pain control

OBJECTIVES

Oesophagectomy is at present considered to be the optimal curative treatment for patients with severe oesophageal disease. Postoperative pain, both acute and chronic, plays a significant role in the quality of life for post-oesophagectomy patients. The present study compared the effects of two methods-application of a non-divided intercostal muscle flap (NIMF) and intercostal nerve cryoanalgesia (INC) treatment-in reducing neuropathic pain in post-oesophagectomy patients.

METHODS

From June 2009 to June 2010, a total of 160 patients who underwent posterolateral thoracotomy and oesophagectomy were subsequently recruited to our study and divided into NIMF groups and INC groups at random. Patient follow-up studies were conducted for one year on all the subjects and the resultant postoperative pain, chronic pain, rehabilitation and complication scored were measured and documented.

RESULTS

INC treatment was more time-intensive than NIMF treatment (P < 0.05). Also, additional chest tube drainage and subsequent extubation were often necessary in the INC group (P < 0.001). No statistically significant differences were found between the two groups regarding the number of subjects who required oral medication one month postoperative with respect to pain score. The chronic pain level, as well as the number of patients requiring oral pain medication, increased significantly by the sixth month following operation and notably increased until the 12th postoperative month in the INC group (P < 0.05).

CONCLUSIONS

Both NIMF and INC treatments were effective and safe for the treatment of acute pain after oesophagectomy. NIMF was the better technique in reducing chronic postoperative pain.

Local anaesthetics and regional anaesthesia for preventing chronic pain after surgery

BACKGROUND

Regional anaesthesia may reduce the rate of persistent (chronic) pain after surgery, a frequent and debilitating condition.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of persistent pain six or 12 months after surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 4), PubMed (1966 to April 2012), EMBASE (1966 to May 2012) and CINAHL (1966 to May 2012) without any language restriction. We used a combination of free text search and controlled vocabulary search. The results were limited to randomized controlled clinical trials (RCTs). We conducted a handsearch in reference lists of included trials, review articles and conference abstracts.

SELECTION CRITERIA

We included RCTs comparing local anaesthetics or regional anaesthesia versus conventional analgesia with a pain outcome at six or 12 months after surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data, including information on adverse events. We contacted study authors for additional information. Results are presented as pooled odds ratios (OR) with 95% confidence intervals (CI), based on random-effects models (inverse variance method). We grouped studies according to surgical interventions. We employed the Chi(2) test and calculated the I(2) statistic to investigate study heterogeneity.

MAIN RESULTS

We identified 23 RCTs studying local anaesthetics or regional anaesthesia for the prevention of persistent (chronic) pain after surgery. Data from a total of 1090 patients with outcomes at six months and of 441 patients with outcomes at 12 months were presented. No study included children. We pooled data from 250 participants after thoracotomy, with outcomes at six months. Data favoured regional anaesthesia for the prevention of chronic pain at six months after thoracotomy with an OR of 0.33 (95% CI 0.20 to 0.56). We pooled two studies on paravertebral block for breast cancer surgery; the pooled data of 89 participants with outcomes at five to six months favoured paravertebral block with an OR of 0.37 (95% CI 0.14 to 0.94).The methodological quality of the included studies was intermediate. Adverse effects were not studied systematically and were reported sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered the assessment of effects, especially at 12 months.

AUTHORS' CONCLUSIONS

Epidural anaesthesia may reduce the risk of developing chronic pain after thoracotomy in about one patient out of every four patients treated. Paravertebral block may reduce the risk of chronic pain after breast cancer surgery in about one out of every five women treated. Our conclusions are significantly weakened by performance bias, shortcomings in allocation concealment, considerable attrition and incomplete outcome data. We caution that our evidence synthesis is based on only a few, small studies. More studies with high methodological quality, addressing various types of surgery and different age groups, including children, are needed.