A randomized controlled trial to measure the effectiveness of a sacral wedge in preventing postoperative back pain following trans-urethral resection of the prostate (TURP) in lithotomy position

Abstract

Background: Postoperative back pain is a common, yet under reported, complication of surgery. Previous studies, although small in number, have indicated that the use of a sacral wedge is effective in reducing the incidence of postoperative back pain.

Aim: The aim of the study was to test the hypothesis that the intra-operative use of a sacral wedge would decrease the incidence of postoperative back pain in patients undergoing trans-urethral resection of the prostate in lithotomy position.

Methods: The design of the study was a randomized controlled trial involving the use of a sacral wedge intra-operatively in a male population undergoing trans-urethral resection of the prostate. A total of 236 participants was recruited to the study and allocated to the control or intervention group by block randomization. All patients selected one of three different sized sacral wedges for use during surgery. Data were collected preoperatively, intra-operatively and at postoperative days 2 and 4 and the tools included a structured questionnaire, Oswestry Disability Questionnaire, a visual analogue scale to measure pain intensity and a body map to record its location.

Results: Fifty-two per cent of participants reported having a history of back pain and point prevalence on admission to hospital was 27%. Twenty-eight per cent of participants experienced back pain on day 2 postoperatively and this decreased to 14% on day 4. There was no significant difference between the control and intervention groups. The severity of back pain increased after surgery. Postoperatively there were reports of back pain from participants who had not reported a history of back pain before their admission for surgery.

Conclusions: In contrast to other studies we found no evidence to support the use of a sacral wedge intra-operatively to reduce the incidence of postoperative back pain.

Relevance to clinical practice: Despite the non-significant results, the high level of postoperative back pain stills draws attention to the need to develop strategies to reduce its incidence.