Chest Wall Analgesia—Where Do We Go From Here?

Guerra-Londono et al¹ present a well-done systematic review and meta-analysis evaluating the benefits and safety of intercostal nerve block (ICNB) analgesia for adults undergoing cardiothoracic surgery compared with systemic analgesia or any other regional technique. The authors used meaningful clinical end points of opioid consumption measured in morphine milligram equivalents (MMEs) and postoperative daily pain scores, and they also assessed 30-day postoperative complications and pulmonary function. Of the 66 studies (5184 patients) reviewed, 51 studies (4690 patients) used single-injection ICNB. The authors found that the use of ICNB was associated with lower pain scores in the first 0 to 6 hours after surgery (static pain: mean score difference, –1.40 points [95% CI, –1.46 to –1.33 points]; dynamic pain: mean score difference, –1.66 points [95% CI, –1.90 to –1.41 points]) and had its largest opioid-sparing benefit at 48 hours after surgery (mean difference, –10.97 MMEs [95% CI, –12.92 to –9.02 MMEs]) compared with systemic analgesia alone. Notably, the authors found that ICNB was noninferior to thoracic epidural analgesia and inferior to paravertebral block with respect to pain scores and was associated with higher MME consumption compared with either of the latter 2 procedures.

As the authors point out, the last decade has seen a substantial increase in the use of minimally invasive techniques in the fields of thoracic surgery and anesthesia.¹ The widespread use of video-assisted thoracoscopic surgery allows thoracic surgeons to readily perform intraoperative ICNB under direct vision. In parallel, technical improvements in imaging technologies, such as ultrasonography, facilitate targeted application of perioperative analgesia to specific peripheral nerves and tissue planes. As physicians and other health care professionals become more facile with these techniques and the cost of imaging devices decreases, analgesic options for any given patient or procedure are likely to increase considerably.² Given the superior benefits of targeted local analgesia and its generally favorable safety profile (not to mention the societal and patient-level adverse effects associated with systemic narcotic therapy), these interventions should be considered essential pain control adjuncts for postsurgical pain.³

However, the devil is in the details, and we, as health care professionals, can still do better. As expressed by Guerra-Londono et al,¹ pain relief from ICNB with local analgesia is transient, lasting a maximum of 48 hours for a single-injection application, which was the technique used among most patients included in this meta-analysis. Pharmacological advances, particularly liposomal bupivacaine, have not been reliably associated with increases in the duration of ICNB analgesia, and optimal pain control from paravertebral block or thoracic epidural analgesia typically lasts for only hours or several days, respectively.^1,4 Inadequate pain control in the later acute postoperative period (≥4 days after a procedure) is associated with increases in the risk of chronic pain, decreases in physical function, and worse quality of life, underscoring the importance of prompt and durable pain control.⁵ Unfortunately, current techniques do not meet these goals, and pain after surgery often outlasts current interventions, leaving patients in need of additional systemic therapy until they reach their pain-free state, or at least a pain nadir. Despite the considerable gains made in perioperative analgesia, we have not yet achieved consistently pain-free thoracic procedures.

In their article, Guerra-Londono et al¹ identified 3 studies^6-8 that compared intercostal cryoneurolysis with ICNB, all of which were conducted before 1990. However, intercostal cryoneurolysis, or cryoablation, is experiencing a resurgence as a pain control modality for patients undergoing thoracic surgery, with techniques and technologies rapidly improving.⁹ Cryoneurolysis involves the application of cold to a nerve, resulting in neurapraxia, axonotmesis, neurotmesis, or transection based on the time and intensity of cold application.¹⁰ Timing of sensory return is contingent on the rate and extent of axon regeneration, which is, in turn, dependent on the time and intensity of the initial cold application and can last weeks to months.¹⁰

The intensity and length of time a patient experiences pain after an operation depends on both patient- and procedure-specific factors. As the application of cryoneurolysis technologies becomes more sophisticated, it is foreseeable that targeted peripheral cryoneurolysis adjusted to a single patient undergoing a given procedure will be possible. This technique could enable personalized patient- and procedure-specific cryoneurolysis rather than a one-size-fits-all approach, as is often practiced. If such sophisticated cryoneurolysis therapy can be developed, then we may be close to the dream of a pain-free surgical experience for patients.

Published: November 15, 2021. doi:10.1001/jamanetworkopen.2021.33839

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Bessoff KE et al. JAMA Network Open.

Corresponding Authors: Joseph D. Forrester, MD, MSc (jdf1@stanford.edu), and Kovi E. Bessoff, MD, PhD (kbessoff@stanford.edu), Section of Acute Care Surgery, Division of General Surgery, Department of Surgery, Stanford University, 300 Pasteur Dr, H3591, Stanford, CA 94305.

Conflict of Interest Disclosures: None reported.