Comparison of epidural analgesia and intercostal nerve cryoanalgesia for post-thoracotomy pain control

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.

Post-Operative Thoracic Epidural Analgesia and Incidence of Major Complications according to Specific Safety Standardized Documentation: A Large Retrospective Dual Center Experience

(1) Background: Thoracic epidural analgesia is considered the gold standard in post-operative pain management following thoracic surgery. This study was designed to explore the safety of thoracic epidural analgesia and to quantify the incidence of its post-operative complications and side effects in patients undergoing thoracotomy for major surgery, such as resection of lung malignancies and lung transplantation. (2) Methods: This is a retrospective, dual-center observational study including patients that underwent major thoracic surgery including lung transplantation and received concurrent placement of thoracic epidural catheters for post-operative analgesia. An electronic system of referral and documentation of complications was used, and information was retrieved from our electronic critical care charting system. (3) Results: In total, 1145 patients were included in the study. None of the patients suffered any major complication, including hematoma, abscess, or permanent nerve damage. (4) Conclusions: the present study showed that in experienced centers, post-operative epidural analgesia in patients with thoracotomy is a safe technique, manifesting minimal, none-serious complications.

Analgesic effectiveness of serratus anterior plane block in patients undergoing video-assisted thoracoscopic surgery: a systematic review and updated meta-analysis of randomized controlled trials

BACKGROUND

Serratus anterior plane block (SAPB) is a promising regional technique for analgesia in thoracic surgery. Till now, several randomized controlled trials (RCTs) have explored the effectiveness of SAPB for postoperative pain control in patients undergoing video-assisted thoracoscopic surgery (VATS), but the sample sizes were small and conclusions remained in controversy. Therefore, we conducted the present systematic review and meta-analysis.

METHODS

RCTs evaluating the analgesic performance of SAPB, comparing to control methods (no block, placebo or local infiltration anesthesia), in patients undergoing VATS were searched in PubMed, EMBASE, Web of Science and Cochrane Library from inception to December 31, 2022. Mean difference (MD) and corresponding 95% confidence interval (95%CI) were calculated for postoperative pain scores at various time points, postoperative opioid consumption and length of hospital stay. Pooled relative risk (RR) with 95%CI were calculated for the risk of postoperative nausea and vomiting (PONV) and dizziness. A random-effect model was applied.

RESULTS

A total of 12 RCTs (837 participants) were finally included. Compared to control group, SAPB had significant reductions of postoperative pain scores at 2 h (MD = -1.58, 95%CI: -1.86 to -1.31, P < 0.001), 6 h (MD = -2.06, 95%CI: -2.74 to -1.38, P < 0.001), 12 h (MD = -1.72, 95%CI: -2.30 to -1.14, P < 0.001) and 24 h (MD = -1.03, 95%CI: -1.55 to -0.52, P < 0.001), respectively. Moreover, SAPB conferred a fewer postoperative opioid consumption (MD = -7.3 mg of intravenous morphine equivalent, 95%CI: -10.16 to -4.44, P < 0.001) and lower incidence of PONV (RR = 0.56, 95%CI: 0.41 to 0.77, P < 0.001). There was no difference between both groups regarding length of hospital stay and risk of dizziness.

CONCLUSION

SAPB shows an excellent performance in postoperative pain management in patients undergoing VATS by reducing pains scores, postoperative opioid consumption and incidence of PONV. However, due to huge heterogeneity, more well-designed, large-scale RCTs are needed to verify these findings in the future.

Intercostal Cryoablation During Video-Assisted Lung Resection Can Decrease Postoperative Opioid Use

OBJECTIVE

Pain requiring opioid use remains an issue even with minimally invasive thoracic surgery. The objective of this study was to investigate the effectiveness of intercostal nerve cryoablation (CRYO) for pain control in adult patients undergoing pulmonary resection.

METHODS

A retrospective analysis of patients undergoing pulmonary resection by uniportal video-assisted thoracic (uVATS) approach was undertaken. Patients treated with our usual pain regimen (STANDARD) were compared with those who additionally received CRYO. STANDARD includes intercostal bupivacaine, patient-controlled analgesia (24 h), ketorolac (48 to 72 h), and tramadol. Intraoperative CRYO was performed on 5 intercostal levels. The primary aim was to compare pain scores (range, 0 to 10) and morphine equivalent dosages (MED). Secondary outcomes included length of stay, chest tube duration, presence of an air leak, and adverse events. A p value <0.05 was considered significant.

RESULTS

There were 49 patients (34 female, 15 male). The median age was 74 (37 to 90) years. Procedures included lobectomy (n = 32), segmentectomy (n = 7), and wedge resections (n = 10). There were 23 (46.9%) CRYO and 26 (53.1%) STANDARD patients. Baseline characteristics were similar. Mean length of stay (2.9 vs 3.5 days), chest tube duration (2.2 vs 1.8 days), and adverse events (9 of 23 vs 7 of 26) were similar. There were no complications attributable to CRYO. Pain scores were not significantly different on postoperative days (POD) 1 to 4. MED was significantly reduced after CRYO on POD 1 (5 vs 47.24), POD 2 (10.93 vs 25.04), POD 3 (8.13 vs 21.7), and POD 4 (7.08 vs 19.17).

CONCLUSIONS

CRYO can be performed safely during pulmonary resection and can decrease in-hospital opioid use. The results from this retrospective study will need to be validated in future prospective studies.

Intercostal Nerve Cryoablation is Associated with Reduced Opioid Use in Pediatric Oncology Patients

INTRODUCTION

Intercostal nerve cryoablation reduces postoperative pain in adults undergoing thoracotomy and children undergoing pectus excavatum repair. We hypothesize that cryoablation is associated with decreased post-thoracotomy pain and opioid use in pediatric oncology patients.

METHODS

A single-center retrospective cohort study was performed for oncology patients who underwent thoracotomy from January 1, 2017 to May 31, 2021. Outcomes included postoperative opioid use measured in morphine milligram equivalents per kilogram (MME/kg), pain scores (scale 0-10), and opioid prescription at discharge. Univariable analysis compared patients who received cryoablation to patients who did not receive cryoablation. Multivariable regression analysis controlling for age and prior thoracotomy evaluated associations between cryoablation and postoperative pain.

RESULTS

Overall, 32 patients (19 males:13 females) underwent thoracotomy with 16 who underwent >1 thoracotomy resulting in 53 thoracotomies included for analysis. Cryoablation was used in 14 of 53 (26.4%) thoracotomies. Throughout the postoperative hospitalization, patients receiving cryoablation during thoracotomy consumed less opioids compared to patients who did not receive cryoablation (median 0.38 MME/kg, interquartile range [IQR] 0.20-1.15 versus median 1.47 MME/kg, IQR 0.71-4.02, P < 0.01). Maximum pain scores were lower in cryoablation patients (median 6, IQR 5-8) than noncryoablation patients (median 8, IQR 6-10), with a significant difference observed on postoperative day 4 (P = 0.01). Cryoablation patients were also less frequently prescribed opioids at discharge (21.4% versus 58.97%, P = 0.02). Multivariable regression demonstrated that cryoablation was associated with 2.59 MME/kg less opioid use (95% confidence interval -4.56 to -0.63) and decreased likelihood of opioid prescription at discharge (adjusted odds ratio 0.14, 95% confidence interval 0.03-0.67).

CONCLUSIONS

Cryoablation is significantly associated with decreased post-thoracotomy pain and opioid use in pediatric cancer patients and should be considered in postoperative pain regimens.

The applications of cryoneurolysis for acute and chronic pain management

BACKGROUND

Cryoneurolysis is a term used to describe the application of extreme cold to targeted nerve tissue. The primary goal of the application of a thermal neurolytic technique is to disrupt the conduction of pain signals from the periphery to the central nervous system and eliminate or diminish the experience of pain. Recent advancements in ultrasound technology coupled with the development and approval of handheld devices specifically designed to deliver cryoneurolysis has expanded the use of this modality in the perioperative setting.

APPLICATION

Surgical procedures including total knee arthroplasties, shoulder arthroplasties, thoracotomies, and mastectomies have all demonstrated long-term pain relief benefits when cryoneurolysis has been administered days to weeks prior to the planned procedure. In addition, the newly designed handheld device allows for office-based clinical use and has been utilized for various chronic pain conditions including neuropathic and phantom limb pain.

CONCLUSION

The evidence clearly demonstrates that cryoneurolysis has a low risk profile and when administered appropriately, provides prolonged analgesia without promoting motor blockade. This narrative review article describes the unique mechanism of action of cryoneurolysis for prolonged pain relief and provides emerging evidence to support its applications in both acute and chronic pain management.

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.

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.

Bony Decompression of a Chronically Painful Intercostal Nerve Yields Immediate and Long-Lasting Pain Relief: A Case Report

CASE

The case of an active 16-year-old adolescent girl who presented with rib malunion and 1 year of unremitting intercostal nerve pain after sustaining multiple rib fractures is presented. She underwent successful bony and soft-tissue decompression of her eighth and ninth intercostal nerves to relieve neurogenic symptoms.

CONCLUSION

When conservative treatment fails, chronic intercostal nerve pain due to chest wall trauma may be effectively managed with surgical bony decompression of the offending intercostal bundle(s). Anatomic knowledge of the intercostal nerve and a critical history and physical examination were critical for accurate diagnosis and surgical decompression of the patient's intercostal nerve.

The effect of continuous intercostal nerve block vs. single shot on analgesic outcomes and hospital stays in minimally invasive direct coronary artery bypass surgery: a retrospective cohort study

BACKGROUND

Minimally invasive direct coronary artery bypass (MIDCAB) grafting surgery is accompanied by severe pain. Although continuous intercostal nerve block (CINB) has become one of the multimodal analgesic techniques in single port thoracoscopic surgery, its effects on MIDCAB are unclear. The purpose of this study was to compare the effects of CINB and single shot on analgesic outcomes and hospital stays in patients undergoing MIDCAB in a real-world setting.

METHODS

A retrospective cohort study was carried out at Peking University Third Hospital, China. Two hundred and sixteen patients undergoing MIDCAB were divided into two groups: a CINB group and a single block (SI) group. The primary outcome was postoperative maximal visual analog scale (VAS); secondary outcomes included the number of patients with maximal VAS ≤ 3, the demand for and consumed doses of pethidine and tramadol, and the length of intensive care unit (ICU) and hospital stays. The above data and the area under the VAS curve in the 70 h after extubation for the two subgroups (No. of grafts = 1) were also compared.

RESULTS

The maximum VAS was lower in the CINB group, and there were more cases with maximum VAS ≤ 3 in the CINB group: CINB 52 (40%) vs. SI 17 (20%), P = 0.002. The percentage of cases requiring tramadol and pethidine was less in CINB, P = 0.001. Among all patients, drug doses were significantly lower in the CINB group [tramadol: CINB 0 (0-100) mg vs. SI 100 (0-225) mg, P = 0.0001; pethidine: CINB 0 (0-25) mg vs. SI 25 (0-50) mg, P = 0.0004]. Further subgroup analysis showed that the area under the VAS curve in CINB was smaller: 28.05 in CINB vs. 30.41 in SI, P = 0.002. Finally, the length of ICU stay was shorter in CINB than in SI: 20.5 (11.3-26.0) h vs. 22.0 (19.0-45.0) h, P = 0.011.

CONCLUSIONS

CINB is associated with decreased demand for rescue analgesics and shorter length of ICU stay when compared to single shot intercostal nerve block. Additional randomized controlled trial (RCT) is needed to support these findings.

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.

Percutaneous Cryoanalgesia: A New Strategy for Pain Management in Pectus Excavatum Surgery

INTRODUCTION

 In recent years, pain protocols for pectus excavatum (PE) have incorporated cryoanalgesia through thoracoscopic approach. Since 2019, ultrasound-guided percutaneous cryoanalgesia (PCr) has been applied at our institution, either on the same day as the Nuss procedure or 48 hours before surgery. We carried out a preliminary retrospective review of patients with PE in whom PCr prior to surgery was performed at our institution between 2019 and 2021.

MATERIALS AND METHODS

 Two groups were evaluated: PCr on the same day (PCrSD) and PCr 48 hours before surgery (PCr48). Despite PCr, patients were treated with "patient-controlled analgesia" (PCA) with opioids for at least 24 hours, switching to conventional intravenous analgesia and oral analgesia in the following days. Demographic, clinical-radiological variables, PCA opioid use, pain grade according to the visual analog scale (VAS), and length of stay (LOS) were compared between the groups. A total of 20 patients were included (12 with PCrSD and 8 with PCr48), without significant differences in demographics or clinical-radiological variables. The overall median time of PCr was 65 minutes (55-127), with no differences between the groups.

RESULTS

 PCr48 group presented with significantly lower median number of hours of continuous PCA (24 vs. 32 hours; p = 0.031), lower median number of rescue boluses (11 vs. 18; p = 0.042), lower median VAS in the early postoperative hours (2 vs. 5.5; p = 0.043), and lower median LOS (3.5 vs. 5 days).

CONCLUSION

 PCr performed 48 hours prior to surgery is more effective in terms of PCA requirements, VAS, and LOS when compared with cryoanalgesia on the same day.

Intercostal Cryo Nerve Block in Minimally Invasive Cardiac Surgery: The Prospective Randomized FROST Trial

INTRODUCTION

Intercostal cryo nerve block has been shown to enhance pulmonary function recovery and pain management in post-thoracotomy procedures. However, its benefit have never been demonstrated in minimal invasive thoracotomy heart valve surgery (Mini-HVS). The purpose of the study was to determine whether intraoperative intercostal cryo nerve block in conjunction with standard of care (collectively referred to hereafter as CryoNB) provided superior analgesic efficacy in patients undergoing Mini-HVS compared to standard-of-care (SOC).

METHODS

FROST was a prospective, 3:1 randomized (CryoNB vs. SOC), multicenter trial in patients undergoing Mini-HVS. The primary endpoint was the 48-h postoperative forced expiratory volume in 1 s (FEV1) result. Secondary endpoints were visual analog scale (VAS) scores for pain at the surgical site and general pain, intensive care unit and hospital length-of-stay, total opioid consumption, and allodynia at 6 months postoperatively.

RESULTS

A total of 84 patients were randomized to the two arms of the trial CryoNB (n = 65) and SOC (n = 19). Baseline Society of Thoracic Surgeons Predictive Risk of Mortality (STS PROM) score, ejection fraction, and FEV1 were similar between cohorts. A higher 48-h postoperative FEV1 result was demonstrated in the CryoNB cohort versus the SOC cohort (1.20 ± 0.46 vs. 0.93 ± 0.43 L; P = 0.02, one-sided two-sample t test). Surgical site VAS scores were similar between the CryoNB and SOC cohorts at all postoperative timepoints evaluated, but VAS scores not related to the surgical site were lower in the SOC group at 72, 94, and 120 h postoperatively. The SOC cohort had a 13% higher opioid consumption than the CryoNB cohort. One of 64 CryoNB patients reported allodynia that did not require pain medication at 10 months.

CONCLUSIONS

The results of FROST demonstrated that intercostal CryoNB provided enhanced FEV1 score at 48 h postoperatively with optimized analgesic effectiveness versus SOC. Future larger prospective randomized trials are warranted to determine whether intercostal CryoNB has an opioid-sparing effect in patients undergoing Mini-HVS.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02922153.

Impact of regional analgesia techniques on the long-term clinical outcomes following thoracic surgery

Continuous monitoring of clinical outcomes after thoracotomy is very important to improve medical services and to reduce complications. The use of regional analgesia techniques for thoracotomy offers several advantages in the perioperative period including effective pain control, reduced opioid consumption and associated side effects, enhanced recovery, and improved patient satisfaction. Postthoracotomy complications, such as chronic postthoracotomy pain syndrome, postthoracotomy ipsilateral shoulder pain, pulmonary complications, recurrence, and unplanned admission to the intensive care unit are frequent and may be associated with poor outcomes and mortality. The role of regional techniques to reduce the incidence of these complications is questionable. This narrative review aims to investigate the impact of regional analgesia on the long-term clinical outcomes after thoracotomy.

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.

Regional anesthetics versus analgesia for stopping the persistent postsurgical pain: A meta-analysis

INTRODUCTION

Regional anesthesia might moderate the risk of persistent postsurgical pain, but its effect compared to systemic analgesia is still conflicting. This meta-analysis study was performed to assess the relationship between the efficiency of regional anesthesia versus systemic analgesia in reducing pain persisting longer than 3 months after surgery.

METHODS

Through a systematic literature search up to August 2020, 31 studies included 2975 subjects who underwent surgery at baseline and reported a total of 1471 subjects using regional anesthesia and 1319 subjects using conventional anesthesia were found recording relationships between efficiency of regional anesthesia versus systemic analgesia in reducing pain persisting longer than 3 months after surgery. Odds ratio (OR) with 95% confidence intervals (CIs) was calculated between regional anesthesia versus systemic analgesia in reducing pain persisting longer than 3 months after surgery using the dichotomous methods with a random or fixed-effect model.

RESULTS

Number of subjects reporting persistent pain 3 months postsurgery was significantly lower in regional anesthesia compared to systemic analgesia in thoracotomy (OR, 0.44; 95% CI, 0.29-0.65, P < .001); breast surgery (OR, 0.46; 95% CI, 0.29-0.72, P < .001); and cesarean section (OR, 0.44; 95% CI, 0.27-0.72, P < .001).

CONCLUSIONS

Regional anesthesia might have an independent relationship with lower pain persisting longer than 3 months after thoracotomy, breast surgery, and cesarean section. Further studies are required to validate these findings.

Efficacy of Perioperative Intercostal Analgesia via a Multimodal Analgesic Regimen for Chronic Post-Thoracotomy Pain During Postoperative Follow-Up: A Big-Data, Intelligence Platform-Based Analysis

Background

Chronic post-thoracotomy pain is still an obstacle for lung-cancer patients even after less invasive surgical procedures. It is unclear whether intercostal analgesia is as useful in the prevention of postoperative chronic pain as it is for acute pain for video-assisted thoracoscopic surgery (VATS). The purpose of this study was to evaluate the efficacy of perioperative intercostal analgesia for chronic pain via a multimodal analgesic regimen for VATS during 6 months of postoperative follow-up.

Methods

We identified 837 cases of VATS from August 2016 to August 2018. Patients were treated by perioperative intercostal analgesia with 0.75% ropivacaine 50 mg through the intercostal catheter every 8 hours until chest tube extubation (INA group) or conventional analgesia with preoperative 0.75% ropivacaine 50 mg at incision once (CON group). Numerical rating scale (NRS) and neuropathic pain were evaluated in 6 months of post-surgery follow-up. Postoperative adverse effects were recorded.

Results

In total, there were 419 patients in INA group and 418 patients in CON group. Scores of NRS with motion was lower in INA group at 3 postoperative days (P = 0.032). Occurrence of chronic pain was 28.4% in INA group and 32.8% in CON group at 6 postoperative months, 10.6% of patients experienced increasing pain from 3 to 6 months. Occurrence of considerable neuropathic pain (ID pain score ≥ 2) was 2.1% in INA group and 3.1% in CON group at 6 postoperative months. No differences were found between the two groups. Occurrence of numbness was lower in INA group (6.7% vs 10.5%, P = 0.031), and other pain symptoms did not differ between the groups. The incidence of dizziness, nausea, vomiting and atelectasis was not different between the two groups.

Conclusion

In a multimodal analgesic regimen of VATS, perioperative intercostal analgesia with 0.75% ropivacaine infusion 50 mg three times in a day does not have an obvious effect on chronic post-thoracotomy pain.

Cryoanalgesia enhances recovery from minimally invasive repair of pectus excavatum resulting in reduced length of stay: A case-matched analysis of NSQIP-Pediatric patients

PURPOSE

Pain control is challenging after minimally invasive repair of pectus excavatum (MIRPE). Cryoanalgesia, which temporarily ablates peripheral nerves, improves pain control and may accelerate post-operative recovery. We hypothesized that cryoanalgesia would be associated with shorter length of stay (LOS) in children undergoing MIRPE.

METHODS

A matched cohort study was conducted of children (<18 years) who underwent MIRPE 2016-2018, using the National Surgical Quality Improvement Program-Pediatric database. Each patient who received cryoanalgesia during MIRPE was matched to four controls (no cryoanalgesia). Univariate and multilevel regression analyses were performed.

RESULTS

Thirty-five patients who received cryoanalgesia during MIRPE were matched to 140 controls. Patients who received cryoanalgesia had a LOS reduction with similar secondary outcomes (operative time, rates of complication, reoperation, and readmission). On multilevel regression adjusted for matched groups, cryoanalgesia was associated with a 1.3-day reduction in LOS (95% CI -1.8 to -0.8, p < 0.001). On sensitivity analysis excluding patients with complications, cryoanalgesia remained associated with a LOS reduction.

CONCLUSIONS

Cryoanalgesia is a promising adjunct in the care of pediatric patients undergoing MIRPE. Utilization is associated with a shorter LOS without an increase in operative time or complications. Cryoanalgesia should be considered for inclusion in enhanced recovery strategies for patients undergoing MIRPE.

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.

Analgesia for Sheep in Commercial Production: Where to Next?

Simple Summary

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on industry to alleviate pain associated with husbandry practices, injury and illness. Although a number of analgesic solutions are now available for sheep, providing some amelioration of the acute pain responses, this review has highlighted a number of potential areas for further research.

Abstract

Increasing societal and customer pressure to provide animals with ‘a life worth living’ continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15–20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000–2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.

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.

CT-guided cryoablation for post-thoracotomy pain syndrome: a retrospective analysis

PURPOSE Post-thoracotomy pain syndrome is a common condition affecting up to 50% of post-thoracotomy patients. However, percutaneous computed tomography (CT)-guided intercostal nerve cryoablation may provide symptomatic benefit in chronic and/or refractory cases. METHODS A retrospective review of our institution's comprehensive case log from October 2017 to September 2018 for patients who underwent cryoablation was analyzed. Thirteen patients with post-thoracotomy pain syndrome, refractory to medical management, were treated with CT-guided intercostal nerve cryoablation. Most patients had treatment of the intercostal nerve at the level of their thoracotomy scar, two levels above and below. The safety and technical success of this technique and the clinical outcomes of the study population were then retrospectively reviewed. RESULTS Of the patients, 69% experienced significant improvement in their pain symptoms with a median pain improvement score of 3 points (range, -1 to 8 points) over a median follow-up of 11 months (range, 2-18.6 months). Complications included pneumothorax in 8% and pseudohernia in 23% of patients. CONCLUSION CT-guided intercostal nerve cryoablation may be an effective technique in the treatment of post-thoracotomy pain syndrome and requires further study.

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.

Anesthetic considerations for lung resection: preoperative assessment, intraoperative challenges and postoperative analgesia

This article is intended to provide a general overview of the anesthetic management for lung resection surgery including the preoperative evaluation of the patient, factors influencing the intraoperative anesthetic management and options for postoperative analgesia. Lung cancer is the leading cause of death among cancer patients in the United States. In patients undergoing lung resection, perioperative pulmonary complications are the major etiology of morbidity and mortality. Risk stratification of patients should be part of the preoperative assessment to predict their risk of short-term vs. long-term pulmonary complications. Improvements in surgical technique and equipment have made video assisted thoracoscopy and robotically assisted thoracoscopy the procedures of choice for thoracic surgeries. General anesthesia including lung isolation has become essential for optimizing visualization of the operative lung but may itself contribute to pulmonary complications. Protective lung ventilation strategies may not prevent acute lung injury from one-lung ventilation, but it may decrease the amount of overall lung injury by using small tidal volumes, positive end expiratory pressure, low peak and plateau airway pressures and low inspired oxygen fraction, as well as by keeping surgical time as short as possible. Because of the high incidence of chronic post-thoracotomy pain syndrome following thoracic surgery, which can impact a patient's normal daily activities for months to years after surgery, postoperative analgesia is a necessary part of the anesthetic plan. Multiple options such as thoracic epidural analgesia, intravenous narcotics and several nerve blocks can be considered in order to prevent or attenuate chronic pain syndromes. Enhanced recovery after thoracic surgery is a relatively new topic with many elements taken from the experience with colorectal surgery. The goal of enhanced recovery is to improve patient outcome by improving organ function and decreasing postoperative complications, and therefore decreasing length of hospital stay.

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.

Pain management in patients with malignant mesothelioma: challenges and solutions

Malignant pleural mesothelioma (MPM) is an aggressive cancer with a considerable symptom burden and poor prognosis. Focus on maintaining patients’ quality of life and pain control is therefore paramount. Pain management in MPM is complex due to its multifactorial etiology resulting from direct tumor infiltration of the surrounding soft tissue, bone, and encasement of the intercostal nerves. A variety of treatment modalities, including pharmacological and non-pharmacological options, are often required to achieve adequate pain control in this challenging disease. This review article examines the current challenges and solutions available for pain management in MPM.

Contributions of Nociresponsive Area 3a to Normal and Abnormal Somatosensory Perception

Traditionally, cytoarchitectonic area 3a of primary somatosensory cortex (SI) has been regarded as a proprioceptive relay to motor cortex. However, neuronal spike-train recordings and optical intrinsic signal imaging, obtained from nonhuman sensorimotor cortex, show that neuronal activity in some of the cortical columns in area 3a can be readily triggered by a C-nociceptor afferent drive. These findings indicate that area 3a is a critical link in cerebral cortical encoding of secondary/slow pain. Also, area 3a contributes to abnormal pain processing in the presence of activity-dependent reversal of gamma-aminobutyric acid A receptor-mediated inhibition. Accordingly, abnormal processing within area 3a may contribute mechanistically to generation of clinical pain conditions. PERSPECTIVE: Optical imaging and neurophysiological mapping of area 3a of SI has revealed substantial driving from unmyelinated cutaneous nociceptors, complementing input to areas 3b and 1 of SI from myelinated nociceptors and non-nociceptors. These and related findings force a reconsideration of mechanisms for SI processing of pain.

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.

Video-assisted thoracoscopic surgery lobectomy with chest wall resection

Lung cancer presents with chest wall invasion in 5-8% of patients, which imparts some treatment challenges. Surgical resection is currently the standard of care, and there are some controversies regarding the best approach. Published series and case reports confirm the safety and feasibility of video-assisted thoracoscopic surgery (VATS) in highly complex surgical cases including lobectomy with chest wall resection of locally advanced lung cancer. In this article, we present the clinical indications of locally advanced lung cancer that infiltrates the chest wall, the modalities for and importance of accurately staging lung cancers with chest wall invasion, and the technical aspects of accomplishing a safe and oncologically sound extended resection through VATS.

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.

The effects of preoperative single-dose thoracic paravertebral block on acute and chronic pain after thoracotomy: A randomized, controlled, double-blind trial

BACKGROUND

Patients undergoing thoracotomy frequently experience acute pain and chronic post-thoracotomy pain (CPTP). There are few articles relating to the investigations on the effects of preoperative single-dose thoracic paravertebral block (PSTPVB) on acute pain and CPTP. We tested the hypothesis that adding PSTPVB to intravenous (IV) patient-controlled analgesia (PCA) would reduce acute pain scores and decrease the incidence and intensity of CPTP.

METHODS

Fifty-six patients undergoing elective thoracotomy were randomized to receive PSTPVB in addition to IV PCA (group T) or IV PCA alone (group C). A single 20-mL injection of 0.50% ropivacaine plus 10 mg dexamethasone in saline was administered preoperatively under ultrasound guidance; sufentanil was used for IV PCA. The acute pain intensity at rest and at coughing based on verbal rating scale, postoperative sufentanil consumption, and complications were evaluated at 6, 24, 48, and 72 hours after surgery. The incidence and intensity of CPTP were evaluated at 3 months after surgery.

RESULTS

Group T had significantly less acute pain compared with group C at all measurement times both at rest and at coughing (P < .05). The PCA cumulative sufentanil consumption, complications, and the incidence of CPTP between the 2 groups was not statistically significant (P > .05). The intensity of CPTP was significantly higher in group C than in group T (P < .05).

CONCLUSION

This study indicated that adding PSTPVB to IV PCA improved acute postoperative pain and chronic pain in patients undergoing thoracotomy, but did not reduce the incidence of CPTP.

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.

Cryoanalgesia in Patients Undergoing Nuss Repair of Pectus Excavatum: Technique Modification and Early Results

PURPOSE

The Nuss procedure for surgical correction of pectus excavatum often causes severe postoperative pain. Cryoanalgesia of intercostal nerves is an alternative modality for pain control. We describe our modification of the cryoICE™ probe that allows for nerve ablation through the ipsilateral chest along with early results utilizing this technique.

METHODS

To allow for ipsilateral nerve ablation, a 20-French chest tube was cut and secured to the cryoICE probe, thus providing insulation for the malleable end of the probe. A 3-year retrospective review of patients undergoing Nuss repair at our institution was performed. Patients who received cryoanalgesia (cryo, n = 6) were compared with a historical control cohort who did not receive cryoanalgesia (nocryo, n = 13) during Nuss repair. Hospital length of stay, postoperative narcotic requirement (PNR), and highest postoperative pain score were collected.

RESULTS

Both cohorts were similar regarding age, BMI, and pectus index. The cryo group had a significantly less PNR (6.4 versus 17.9 doses, P = .05) and was discharged on average >1 day earlier than nocryo patients (3.7 versus 2.2 days, P = .01). No complications occurred in either group.

CONCLUSIONS

Our technique modification simplifies previously described approaches to intercostal nerve cryoablation. Patients undergoing this adjunct benefit with less PNR and a faster discharge time.

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 Prospective Study of Chronic Pain after Thoracic Surgery

BACKGROUND

The goal of this study was to detect the predictors of chronic pain at 6 months after thoracic surgery from a comprehensive evaluation of demographic, psychosocial, and surgical factors.

METHODS

Thoracic surgery patients were enrolled 1 week before surgery and followed up 6 months postsurgery in this prospective, observational study. Comprehensive psychosocial measurements were assessed before surgery. The presence and severity of pain were assessed at 3 and 6 months after surgery. One hundred seven patients were assessed during the first 3 days after surgery, and 99 (30 thoracotomy and 69 video-assisted thoracoscopic surgery, thoracoscopy) patients completed the 6-month follow-up. Patients with versus without chronic pain related to thoracic surgery at 6 months were compared.

RESULTS

Both incidence (P = 0.37) and severity (P = 0.97) of surgery-related chronic pain at 6 months were similar after thoracotomy (33%; 95% CI, 17 to 53%; 3.3 ± 2.1) and thoracoscopy (25%; 95% CI, 15 to 36%; 3.3 ± 1.7). Both frequentist and Bayesian multivariate models revealed that the severity of acute pain (numerical rating scale, 0 to 10) is the measure associated with chronic pain related to thoracic surgery. Psychosocial factors and quantitative sensory testing were not predictive.

CONCLUSIONS

There was no difference in the incidence and severity of chronic pain at 6 months in patients undergoing thoracotomy versus thoracoscopy. Unlike other postsurgical pain conditions, none of the preoperative psychosocial measurements were associated with chronic pain after thoracic surgery.

Efficacy and safety of multimodal analgesic techniques for preventing chronic postsurgery pain under different surgical categories: a meta-analysis

The purpose of this meta-analysis was to compare the efficacy and safety of regional anesthesia to manage chronic postsurgery pain. A systematic search of PubMed, EmBase, and the Cochrane Central Register of Controlled Trials was performed to identify randomized controlled trials that focused on chronic pain frequency, analgesic consumption, and adverse effects under different surgical categories. We collected 21 trials assessing 1,980 patients for our meta-analysis. The summary of relative risks (RRs) and standard mean differences (SMDs) were calculated to measure the treatment effect of regional anesthesia. Results indicated that regional anesthesia significantly reduced the frequency of postsurgery pain (RR, 0.69; 95% confidence interval [CI], 0.56–0.85; p < 0.001). The results showed significant differences in overall patient satisfaction between applications with and without regional anesthesia (SMD, 1.95; 95%CI, 0.83–3.06; p = 0.001); however in other results, there were no significant differences between the two groups. Subgroup analysis suggested that regional anesthesia treatment might differ according to country. In conclusion, our study indicated that regional anesthesia was effective and safe in reducing the frequency of postsurgery pain and improved overall patient satisfaction; however, studies on the long-term efficacy and safety of regional anesthesia are still required to further confirm these findings.

Interventional Analgesic Management of Lung Cancer Pain

Lung cancer is one of the four most prevalent cancers worldwide. Comprehensive patient care includes not only adherence to clinical guidelines to control and when possible cure the disease but also appropriate symptom control. Pain is one of the most prevalent symptoms in patients diagnosed with lung cancer; it can arise from local invasion of chest structures or metastatic disease invading bones, nerves, or other anatomical structures potentially painful. Pain can also be a consequence of therapeutic approaches like surgery, chemotherapy, or radiotherapy. Conventional medical management of cancer pain includes prescription of opioids and coadjuvants at doses sufficient to control the symptoms without causing severe drug effects. When an adequate pharmacological medical management fails to provide satisfactory analgesia or when it causes limiting side effects, interventional cancer pain techniques may be considered. Interventional pain management is devoted to the use of invasive techniques such as joint injections, nerve blocks and/or neurolysis, neuromodulation, and cement augmentation techniques to provide diagnosis and treatment of pain syndromes resistant to conventional medical management. Advantages of interventional approaches include better analgesic outcomes without experiencing drug-related side effects and potential for opioid reduction thus avoiding central side effects. This review will describe various pain syndromes frequently described in lung cancer patients and those interventional techniques potentially indicated for those cases.