Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 49 4 2011 04 15 241 245 EN Sirous Momenzadeh Department of Anesthesiology & Pain, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Hedayatollah Elyasi Research Center of Anesthesiology, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Naser Valaie Department of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Badiozaman Radpey Department of Anesthesiology, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Azizollah Abbasi Department of Thoracocic Surgery, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Fatemeh Nematollahi Department of Anesthesiology & Pain, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Hossein Mohammadinasab Research Center of Anesthesiology, Taleghani Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2015 09 28 We prepared this study to determine the effect of cryoanalgesia on post-thoracotomy pain. In this double-blinded randomized clinical trial, 60 patients who underwent thoracotomy were divided into two groups (control and cryoanalgesia). Visual Analogue Scale (VAS, 0-10) was used for the measurement of severity of post-thoracotomy pain. It was classified into three categories: 0-1 (mild), 2-3 (moderate), and 4-10 (severe). Pethidine (0.5-1 mg/kg) was administered in case of need for both groups. Patients were visited at the hospital a week later, and were contacted by phone at the first, second, and third months post-operatively. Intensity of pain in the control group was higher than the cryoanalgesia group in all visits the follow-up period. On the second day, the frequencies of severe pain (4-10) were 33.3% and 0 in the control and cryoanalgesia groups, respectively. The mild pain on the seventh day was 13.3% and 83.3% in the control and cryoanalgesia groups, respectively (P < 0.01). Pethidine consumption was 151.6 ± 27 mg in the control group and 87.5 ±48 mg in the cryoanalgesia group on the first day post-operation (P < 0.001). Cryoanalgesia is a useful technique with not serious side effects in order to alleviate post-thoracotomy pain and reduce the need for opiate consumption. https://acta.tums.ac.ir/index.php/acta/article/view/3731 https://acta.tums.ac.ir/index.php/acta/article/download/3731/3706