S(+)-ketamine for control of perioperative pain and prevention of post thoracotomy pain syndrome: a randomized, double-blind study.

S(+)-ketamine had no effects in respect to placebo in the prevention of PTPS at 3 and 6 months but had a significant role in maintaining a NRS≤3 in the early postoperative period. A tight control of perioperative pain seems to be associated with a low incidence of moderate and severe PTPS.