Objective: Continuous bupivacaine paravertebral nerve block after thoracotomy has been shown to reduce postoperative pain. This study was designed to determine whether paravertebral nerve block using bupivacaine infused through a catheter placed intraoperatively, can reduce postoperative pain, and analgesia requirements after loin incision.
Methods: Thirty-four patients undergoing renal surgery through loin incision at Jordan University Hospital, Amman, Jordan, from October 2001 to March 2003, were randomized either to receive bupivacaine 0.5% or normal saline through a catheter positioned intraoperatively against the costovertebral joints in the paravertebral space. The infusions were continued until the evening of the third postoperative day. Patients had access on request to intramuscular Morphine sulphate 5-15 mg, or Diclofenac sodium 50-100 mg, or both depending on body weight. Pain after operation was assessed at rest using linear visual analogue scale. Patient scores were recorded in the recovery room, at 4 hours, 8 hours, and at 9 am, and 5 pm.
Results: The analgesia requirements for each patient were recorded. Pain scores in the recovery room were significantly lower in the bupivacaine group (mean 4.5 versus 8.0, p=0.001). At 4 hours, the pain score was lower in the bupivacaine group though not significant (mean 3.5 versus 4.37, p=0.393). Thereafter, the pain scores were significantly lower in the bupivacaine group. Mean morphine requirement in the bupivacaine group was 13.3 mg (ranges 0-50), while in the saline group 40.13 mg (range 10-112.5), p<0.001. Morphine requirements in the first and second postoperative days were significantly less in the bupivacaine group (p=0.015 and p=0.03).
Conclusion: Paravertebral blockade using bupivacaine is an effective and safe method for pain relief following renal surgery through loin incision.