Is cryoanalgesia effective for post-thoracotomy pain?: Table 1:

Abstract

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.

Novel cryoneurolysis device for the treatment of sensory and motor peripheral nerves

“…Other randomized, controlled trials have shown that cryodenervation significantly reduces persistent postsurgical pain and/or opiate requirements following thoracotomy [65] and tonsillectomy [66].…”

Ultrasound-guided percutaneous cryoneurolysis for treatment of acute pain: could cryoanalgesia replace continuous peripheral nerve blocks?

“…With the advent of ultrasound-guided probe insertion, 5 cryoneurolysis was used to provide analgesia for multiple chronic pain states. 2 While cryoneurolysis has been used to treat acute pain following herniorrhaphy, 6 7 tonsillectomy 8 and thoracotomy via the surgical incision, 9 percutaneous administration theoretically increases the potential scenarios for its use to provide analgesia. 10 The use of ultrasound guidance for percutaneous perineural cannula insertion dramatically increases potential applications yet further.…”

“…24 In contrast, the majority of randomized controlled trials of cryoneurolysis via the surgical incision did not report any increased risk of persistent postoperative pain, although a few additional small studies did note a possible association that did not reach statistical significance. 9 The reasons for these discrepancies remain unknown, and because of a myriad of confounding variables among studies (e.g. number of intercostal nerves ablated, chest drain location, number of treatment cycles, duration of treatment, cryoneurolysis temperature), no causal inferences can be made without additional data.…”

“…number of intercostal nerves ablated, chest drain location, number of treatment cycles, duration of treatment, cryoneurolysis temperature), no causal inferences can be made without additional data. 9 Considering the lack of reports of chronic pain following cryoneurolysis for other indications, 2 and given a small series of patients treated for post-thoracotomy neuralgias with percutaneous cryo-ablation whose pain worsened following treatment, 25 this may be an issue related exclusively to thoracotomy-possibly related to the double-crush theory because of the high incidence of surgical procedure-related nerve injury during open thoracotomy. Many questions remain regarding ultrasound-guided percutaneous cryoneurolysis for the treatment of acute pain.…”

“…For example, yet to be defined are the applicable acute pain indications, 2 the optimal cryo-ablation technique and equipment, 11 the ways to better control hypoesthesia (block) duration and an effort to determine the risk-if any-of post-procedure neuropathic pain. 9 Nevertheless, current evidence suggests that ultrasound-guided percutaneous cryoanalgesia holds enormous potential for making a dramatic leap forward in providing longterm analgesia far surpassing typical continuous peripheral nerve blocks, with minimal risk and a lower patient burden (e.g. carrying a local anaesthetic reservoir).…”