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.