Cryoanalgesia for pain management after open thoracotomy

We read the recently updated PROSPECT recommendations on pain management after open thoracotomy 1. Whilst we commend the authors for their comprehensive review of multimodal analgesic strategies, we wish to highlight concerns regarding their endorsement of cryoanalgesia when regional techniques prove impractical. Our clinical and experimental data indicate that this intervention may carry a risk of chronic neuropathic pain following thoracic surgery. In 2008, we conducted a randomised controlled trial comparing thoracic epidural analgesia with intercostal nerve cryoanalgesia in 107 patients undergoing open thoracotomy 2. Both techniques provided equivalent acute pain relief during the first three postoperative days. However, patients receiving cryoanalgesia exhibited a significantly higher incidence of moderate-to-severe chronic pain that interfered with daily activities at 6 and 12 months. Moreover, a greater proportion of these patients reported allodynia-like pain. These findings led us to conclude that cryoanalgesia may exacerbate neuropathic pain after thoracotomy. The PROSPECT review cites two randomised trials to support cryoanalgesia 3, 4, yet both have substantial limitations regarding chronic pain assessment in open thoracotomy. Ba et al. compared cryoanalgesia with parecoxib but did not evaluate long-term neuropathic outcomes 3. Lau et al. reported minimal allodynia at 6 months, yet their study examined minimally invasive cardiac surgery through small thoracotomies 4. This is a population with lower chronic pain risk than patients undergoing open lateral thoracotomy for pulmonary resection 4. The control group comprised only 19 patients, further limiting statistical power to detect meaningful differences in neuropathic pain incidence. Given these findings, we question the appropriateness of recommending cryoanalgesia as a routine alternative when regional blocks are unavailable. Surgical intercostal nerve blockade performed under direct vision offers comparable acute analgesia without the attendant risk of persistent neuropathic pain 5. We urge clinicians to weigh the short-term benefits of cryoanalgesia against its potential to inflict lasting pain that substantially impairs quality of life. Future guidelines should incorporate more robust evidence on chronic pain outcomes before endorsing this technique for open thoracic procedures.