Mechanism research of cryoanalgesia

Abstract

The sciatic nerves of rabbits were frozen at different temperatures (-20°C/ - 60°C, - 700°C, - 140°C, and - 180°C). The morphology and function of the frozen nerves were examined with light microscopy (hematoxylin and eosinophilin stain and a histochemical thiocholine method) and electron microscopy. The function of the nerve after freezing was assessed using short latency somatosensory evoked potentials, sensory conduction velocity, and electromyogram at various intervals after freezing. There were no changes in morphology or function of nerves cryolesioned at - 20°C. The nerve fibers cryolesioned at -60°C showed signs of freezing degeneration and lost their conductive function although, these nerves all recovered. Approximately half of nerve fibers cryolesioned at -100°C showed Wallerian degeneration, and although the time to remyelination was delayed, nerve regeneration was still complete. At -140°C and -180°C the nerve fibers showed immediate necrosis, with destruction of basal membranes and proliferation of collagen fibers. The results explained the mechanism of cryoanalgesia. Our study demonstrates that cryo-temperatures lower than - 140°C will cause permanent alterations in nerve morphology and function, whereas warmer temperatures do not result in permanent nerve damage and are therefore not likely to provide long-term analgesia to patients. [Neurol Res 1995; 17: 307-311]     

精准肋间神经冷冻止痛在胸腔镜纵隔肿瘤切除术中的初步应用

目的探讨精准肋间神经冷冻止痛在胸腔镜纵隔肿瘤切除术中的效果。方法选取2011年1月至2014年1月间行胸腔镜纵隔肿瘤切除术患者60例,随机分为试验组和对照组,每组30例。试验组患者术中施行精准解剖肋间神经分支冷冻止痛,对照组患者施行术后自控静脉镇痛(PCIA)。术后观察记录镇痛药物用量、疼痛评分(VAS)及术后并发症的发生情况。结果试验组患者术后镇痛药物用量、疼痛评分及并发症发生率均明显低于对照组,差异有统计学意义(P<0.01)。结论精准肋间神经冷冻止痛能有效缓解患者术后疼痛,并且能够减少术后并发症的发生,是一种安全有效的止痛方法。     

Cryoanalgesia in the management of intractable pain in the temporomandibular joint: a five-year retrospective review

Cryoanalgesia is a controversial adjunct to the management of chronic pain, but we know of no studies that have investigated its effect in the management of temporomandibular joint (TMJ) pain. In this five-year retrospective study we treated 17 patients who had severe pain that had failed to respond to all forms of conventional conservative treatment and were not appropriate for simple open operation. None had a clear indication for open operation on the joint or had too severe disease to warrant a simple procedure. Preliminary diagnostic injections of bupivacaine to the TMJ relieved the pain. We applied the cryoprobe in the region of the auriculotemporal nerve and TMJ capsule. There was a small but insignificant improvement in mean mouth opening together with a significant (p = 0.000) improvement in visual analogue pain scores (VAS) from 6.8 (range 4–10) to 2.0 (range 0–7). Two patients had no change in their pain scores, and 2 had complete resolution of their pain. The mean number of pain-free months after treatment was 7 (IQR 3–15). Three patients had long-term pain relief, and 12 temporary relief; 6 of these subsequently had successful relief after total replacement of the TMJ. One patient had further cryoanalgesia, one was referred for specialist pain management, and one controlled the pain with nortriptyline. Of the 17 cases studied, 2 had temporary complications after cryoanalgesia. Cryoanalgesia is a useful adjunct to the management of intractable pain in the TMJ. Short-term pain relief can be achieved, and long-term relief is possible in some, deferring more complex and costly treatments.     

Percutaneous cryoanalgesia for pain palliation: Current status and future trends

Cryoanalgesia, otherwise termed cryoneurolysis, refers to application of extreme cold upon peripheral nerves for palliation of pain associated to nerve lesions or biomechanical syndromes of neoplastic and non-neoplastic substrate. Application of cryoanalgesia initiates a cascade of pathophysiologic events interrupting nerve conduction of painful stimuli without irreversible nerve damage. Cryoanalgesia is considered a safe procedure with minimal risk of complications when performed with percutaneous approaches under imaging guidance. In the era of an opioid overdose crisis, cryoanalgesia can be proposed as an alternative aiming at controlling pain and improving life quality. Imaging guidance has substituted open surgical and nerve stimulation approaches in nerve identification, significantly contributing to the minimally invasive character of percutaneous approaches. Ultrasound or computed tomography can serve as low cost, ideal guiding techniques due to their abilities for precise anatomic delineation, high spatial resolution and good tissue contrast. The purpose of this review is to become familiar with the most common imaging guided percutaneous cryoanalgesia indications, to learn about different technical considerations during performance providing the current evidence. Controversies concerning products will be addressed.     

Impact of Cryoanalgesia Use During Minimally Invasive Pectus Excavatum Repair on Hospital Days and Total Hospital Costs Among Pediatric Patients

IntroductionSurgical repair of pectus excavatum is a painful procedure requiring multimodal pain control with historically prolonged hospital stay. This study aimed to evaluate the impact of cryoanalgesia during minimally invasive repair of pectus excavatum (MIRPE) on hospital days (HDs), total hospital costs (HCs), and complications. We hypothesized that cryoanalgesia would be associated with reduced HDs and total HCs with no increase in post-operative complications.MethodsWe conducted a retrospective review of pediatric patients who underwent MIRPE from 2011 to 2021. MIRPE details and post-operative outcomes within 90 days were abstracted. Total HDs included the index MIRPE admission and readmissions within 90 days. HCs were obtained from the hospital accounting system, retroactively adjusting for medical inflation. Bayesian generalized linear models with neutral prior assuming no effect were used. Differences between treatment groups were assessed using gamma distribution (HDs and HCs) and poisson (post-operative complications). All models used log link and controlled for age, gender, race, and Haller index.ResultsForty-four patients underwent MIRPE during the study period. Cryoanalgesia was utilized in 29 (66%) patients. The probability of a reduction with cryoanalgesia vs. no cryoanalgesia was 99% for HDs (3.0 vs. 5.4 days; Bayesian RR: 0.6, 95% CrI: 0.5–0.8), 89% for HCs ($18,787 vs. $19,667; RR: 0.9, 95% CrI: 0.8–1.1), and 70% for postoperative complications (17% vs 33%; RR: 0.8, 95% CrI: 0.3–1.9).ConclusionCryoanalgesia use in MIRPE likely reduced HDs, HCs, and post-operative complications. Further research is warranted to confirm these findings in large prospective studies.Level of EvidenceLevel III.     

精确肋间神经冷冻在老年患者胸腔镜手术中的初步应用

目的观察精准肋间神经冷冻止痛术用于老年患者胸腔镜手术后镇痛的临床疗效。方法 2013年6月~2014年6月期间,于解放军总医院胸外科接受胸腔镜手术的老年患者60名,按随机数字表法随机分为2组,每组30例,肋间神经冷冻止痛组(A组),术中施行精确解剖肋间神经分支冷冻止痛术,对照组施行术后自控静脉镇痛(patient-controlled intravenous analgesia,PCIA)(B组)。术后根据视觉模拟疼痛评分(visual analogus scale,VAS)对疼痛进行评价,并观察记录术后肺部并发症的发生情况。结果术后第1、3、5、7天,A组术后疼痛评分均明显低于B组(P0.01)。术后A组、B组肺部并发症发生率都较低,两组对比差异无统计学意义。结论精准肋间神经冷冻止痛能有效缓解老年患者胸腔镜术后疼痛,并且在一定程度上能够减少术后并发症的发生,是一种安全有效的止痛方法。     

肋间神经冷冻术在胸部手术后镇痛的临床研究

目的探讨肋间神经冷冻在胸部术后的镇痛效果。方法将200例单纯后外侧切口开胸手术患者随机分为观察组（肋间神经冷冻治疗组）100例和对照组100例,比较两组患者术后镇痛效果、肺部并发症发生率、术后使用麻醉镇痛药及肺功能情况。结果观察组患者疼痛程度显著弱于对照组（P〈0．01）;术后咳嗽、咳痰评分优良率显著高于对照组（P〈0．01）;肺部并发症发生率显著低于对照组（P〈0．01）;术后3d内镇痛药需求量也显著低于对照组（P〈0．01）。观察组术后肺功能恢复时间较快,肺功能在术后第3天及第7天与对照组相比有显著差异（P〈0．01）。结论肋间神经冷冻治疗对开胸手术后镇痛效果明显,能减少肺部并发症发生,且不会对肋间神经造成永久性损害,是一种简便、有效、安全的镇痛方法,值得临床大力推广使用。     

肋间神经冷冻止痛的临床应用

目的 探索应用冷冻治疗肋间神经痛的疗效和方法。方法 将50例需开胸手术的患者随机分成两组，冷冻组与对照组各25例。冷冻组手术结束前冷冻切口、上下各一肋间以及放置引流管之肋间神经根部，根据视觉模拟评分法观察术后切口疼痛以及止痛药使用情况；对照组不用冷冻治疗。结果冷冻组止痛效果极为满意，VAS评分为2．14。而对照组为7．9，差异有非常显著性意义（P〈0．01）；冷冻组总有效率为92％，吗啡平均用量为2．3mg；而对照组总有效率52％，吗啡平均用量为16．4mg，两组差异有非常显著性意义（P〈0．01）。结论 冷冻肋间神经能够有效地预防开胸术后剧烈胸痛。     

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

Epidural analgesia is regarded as the gold method for controlling post‐thoracotomy pain. Intercostal nerve cryoanalgesia can also produce satisfactory analgesic effects, but is suspected to increase the incidence of chronic pain. However, randomized controlled trials comparing these two methods for post‐thoracotomy acute pain analgesic effects and chronic pain incidents have not been conducted previously. We studied 107 adult patients, allocated randomly to thoracic epidural bupivacaine and morphine or intercostal nerve cryoanalgesia. Acute pain scores and opioid‐related side effects were evaluated for three postoperative days. Chronic pain information, including the incidence, severity, and allodynia‐like pain, was acquired on the first, third, sixth and twelfth months postoperatively. There was no significant difference on numeral rating scales (NRS) at rest or on motion between the two groups during the three postoperative days. The patient satisfaction results were also similar between the groups. The side effects, especially mild pruritus, were reported more often in the epidural group. Both groups showed high incidence of chronic pain (42.1–72.1%), and no significance between the groups. The incidence of allodynia‐like pain reported in cryo group was higher than that in Epidural group on any postoperative month, with significance on the sixth and the twelfth months postoperatively (P<0.05). More patients rated their chronic pain intensity on moderate and severe in cryo group and interfered with daily life (P<0.05). Both thoracic epidural analgesia and intercostal nerve cryoanalgesia showed satisfactory analgesia for post‐thoracotomy acute pain. The incidence of post‐thoracotomy chronic pain is high. Cryoanalgesia may be a factor that increases the incidence of neuropathic pain.     

冷冻肋间神经预防胸部手术后疼痛的临床观察研究

目的 探讨肋间神经冷冻术预防开胸术后疼痛的效果及并发症的发生.方法 随机选取行开胸术的患者578例为冷冻组(A组),并随机选取同期行开胸手术的患者137例为对照组(B组).观察各组患者术后疼痛及止痛药的使用情况,并观察其并发症的发生情况.结果 A组止痛有效率与B组相比差异有统计学意义(P＜0.05);且并发症发生率差异亦有统计学意义(P＜0.05).结论 肋间神经冷冻能有效预防开胸术后剧烈疼痛,减少并发症,值得推广.