Comparison Between Epidural Technique and Mid-axillary Ultrasound-guided TAP Block for Postoperative Analgesia of Laparoscopic Radical Prostatectomy. Impact on Early Discharge

After approval from Institutional Review Board (approval number 16/42) and compliance with the Declaration of Helsinki; and complying with the information checklist of Consolidated Standards of Reporting trials (CONSORT), informed consent was obtained from all those patients who underwent LRP between October 2016 and May 2018.

Exclusion criteria were: age below 18 years old; American Society of Anaesthesiologists (ASA) score ≥IV; body mass index (BMI) ≥30 Kg/m-2; history of local anaesthetic (LA) allergies; chronic opioid use, coagulopathy; peripheral neuropathy; reconversion to open surgery; or patient's refusal of consent.

Patients were randomized to either TAP or epidural group according to sequential recruitment criteria performed at the pre-operative visit. At this point, age, anaesthesia ASA score and BMI was also recorded.

Management of patients undergoing LRP - intraoperatively All patients underwent combined anaesthesia: either general anaesthesia + epidural; or general anaesthesia + TAP block (TAP group). Patients were premedicated with intravenous midazolam 0.05 mg/Kg-1. In the epidural group, a catheter was placed at L1-L2 level, and tested, prior to induction. Induction was performed intravenously with fentanyl (1.5 mcg/Kg-1), propofol (1.5-2 mg/Kg-1), and rocuronium (0.6 mg/Kg-1). Orotracheal intubation was performed. Prior to skin incision 8 mL of 0.25% levo-bupivacaine were administered epidurally, and a continuous perfusion of 0.125% levo-bupivacaine at 5 mL was started. In the TAP group, a bilateral, ultrasound-guided mid-axillary TAP block was performed immediately after induction (the same as epidural group) but prior to surgery. The high-frequency lineal probe (Sonosite MicroMAXXTM) was placed midway between the costal margin and iliac crest, and transversus abdominis muscle (TAM) located behind the rectus abdominis and below the internal oblique muscle (IOM). 20 mL of LA (bupivacaine 0.375%) was administered via a 22-gauge Quincke spinal needle inserted in-plane on each side of the abdomen. A block was considered successful whenever interfascial local anaesthetic spread was evident under ultrasound vision.

A laparoscopic radical prostatectomy was performed. Intraoperative anaesthetic maintenance was performed with propofol target-controlled infusion (TCI) for bispectral index between 40 and 60. Net zero fluid therapy was maintained, as well as normothermia, normotension and optimal intraoperative analgesia following ERP criteria. After surgery, patients were awoken from general anaesthesia and transferred to the post-anaesthesia care unit (PACU) for a 6-hour follow-up prior to transfer to conventional ward.