Pain relief after open radical prostate surgery: the use of a subcutaneous local anaesthetic solution.

Postoperative pain relief for patients undergoing open radical prostatectomy (surgical removal of the prostate gland via a lower abdominal surgical incision) is provided by either strong painkillers such as intravenous morphine (delivered into the peripheral vein of the patient), or by the infusion of a local anaesthetic solution via an epidural catheter, which is inserted by an anesthetists into the epidural space that surrounds the spinal cord. The local anaesthetic solution acts by numbing the nerves around the spinal cord thereby providing pain relief from the surgical wound. One alternative method of administering the local anaesthetic solution for its beneficial effects without the inherent risks of epidural insertion is to administer the local anaesthetic solution directly into the patient’s circulation via a peripheral vein. Many well-designed studies investigating patients undergoing major abdominal surgery have shown that this method of administering the local anaesthetic solution provides excellent pain relief with minimal side effects. This technique also has beneficial effects on early postoperative return on bowel function. The administration of local anaesthetic solutions via this route is inexpensive, easy to administer, and safe. There is only one published clinical trial investigating this technique in patients undergoing radical prostatectomy. The main end point of this study was return of bowel function. However, it is not known if the addition of a systemic local anaesthetic solution with morphine accelerates postoperative recovery and shortens the duration of hospital stay. This research study will investigate this precise question. The purpose of the study is to compare whether the use of a lignocaine infusion together with intravenous morphine reduces time to readiness for discharge compared to using intravenous morphine alone. Adult patients undergoing elective open radical prostatectomy will be invited to participate. Patients will be approached and consented for surgery in the Urology or Anaesthetic Outpatient Clinics. All patients will have general anaesthesia and surgery performed accordance to the standard practice of their caring surgeons and anaesthetists. All patients will receive intravenous morphine together with simple pain relief adjuvants such as paracetamol and non-steroidal anti-inflammatory tablets. This is standard practice at Austin Hospital for all patients undergoing this operation. Consenting patients will be randomised into 2 groups. One group will receive an infusion of a local anaesthetic solution (ligonacaine); the other group will receive a placebo solution of normal saline. Neither the patient nor anaesthetist (or any member of the surgical or nursing team) will know which group the patient has been randomised to. This study is therefore a prospective double-blinded, randomised, placebo-controlled trial. This is the gold standard experimental research design. The main study aim will be to collect data from the patient’s postoperative records and assess when the patient is ready for hospital discharge. Other secondary end points collected will include pain and sedation scores, return of bowel function, cumulative morphine use, need for rescue pain medication and side effects of morphine and the local anaesthetic solution. Standard and specialised statistical tests will be used to analyse differences between the two groups of patients. All patients will be managed by the Austin Hospital acute pain service guidelines, in accordance with standard practices and infusion protocols.