Outpatient inguinal hernia repair under local anaesthesia: feasibility and efficacy of ultrasound-guided transversus abdominis plane block

The aim of this prospective randomized study was to determine the utility of transversus abdominis plane (TAP) block to improve the efficacy of conventional local anaesthesia for hernia repair in order to achieve an adequate anaesthesia and to evaluate its post-operative analgesic effectiveness. Hundred and fifty consecutive male patients undergoing outpatient hernia repair (Lichtenstein technique) were enrolled in this study. Patients were randomly allocated to undergo a combined TAP block and local anaesthesia (case group) or single conventional local anaesthesia (control group). The study was designed to obtain a 1:2 case-control ratio. The primary outcome was the evaluation of the proportion of patients achieving an adequate anaesthesia. The secondary outcome was the evaluation of pain on movement, pain at rest, rescue analgesia need, nausea and satisfaction. An adequate anaesthesia was achieved in 8 % case and in 36 % control subjects (p = 0.001). At the 6 and 12 h post-operative evaluations, patients enrolled in the case group reported significantly less pain (evaluated by VAS score) both at rest and on movement (p always = 0.001). Moreover, the need of rescue analgesia resulted significantly higher in the control group (14 vs. 32 %, p = 0.01). Our results demonstrated that, as compared with conventional local anaesthesia, the combination of TAP block with local anaesthesia showed a higher efficacy in the obtainment of an adequate anaesthesia and in the post-operative pain control for hernia repair.