[Postoperative analgesia: epidural injection of dexamethasone sodium phosphate]

Epidural administration of steroids has been suggested for the prevention of postoperative epidural fibrosis after lumbar lamino-arthrectomy. In order to assess the efficacy of this technique on pain occurring after such surgery, the demand of pentazocine during the first 24 postoperative hours was studied in 39 patients randomly assigned to two groups. Pain intensity was assessed by a five-point verbal scale (0: none; 1: poor; 2: moderate; 3: severe; 4: very severe) at five intervals (0-4, 5-8, 9-12, 13-16 and 17-24 h). The patients in group T (n = 20) did not receive any steroid, whereas those in group C (n = 19) were given, just after the end of surgery, a single dose of dexamethasone (4 mg) via an epidural lumbar catheter previously inserted by the surgeon. In group T, 18 patients required one or several intramuscular injections of pentazocine, whereas only three patients of group C (p less than 0.001) did so. Patients in group T expressed more severe pain (4 moderate, 12 severe, 3 unbearable) than those patients who had received steroids (1 moderate, 1 severe, 1 unbearable). As a consequence, they requested more pain killer (30 injections vs 8 injections, respectively; p less than 0.001) and sooner than patients of the steroid group (8 h vs 12 h; p less than 0.05). It was concluded that epidural administration of dexamethasone was helpful in preventing postoperative pain after lumbar lamino-arthrectomy.