Cryoanalgesia after thoracotomy. Improvement of technique and review of 600 cases.

The efficacy of cryoanalgesia for the control of post-thoracotomy pain has led to the acceptance of the technique as a routine procedure in this unit. A study of 600 consecutive patients in whom an improved technique was used is not reported. The freezing time for each intercostal nerve in this group was reduced to one 30 second exposure instead of the two 30 second exposures previously used. This reduced the duration of cutaneous numbness, with no loss of pain control. Freezing above the fifth intercostal nerve is no longer practiced in women. Modification to the probe has simplified the procedure. Pulmonary function studies and blood-gas analysis are also described.