[Comparison of two methods of pre-emptive infiltration anaesthesia for inguinal hernia repair].

BACKGROUND: Intraarticular injection of neostigmine has been reported to create long-lasting analgesia due to the blockade of muscarinic receptors and neuronociceptive transmitters. The aim of the study was to determine if similar effects could be achieved after adding neostigmine to bupivacaine during infiltration of the surgical area before inguinal hernia surgery.

METHODS: Ninety patients (82 males and 8 females), aged 20-88 (mean 54.8) years, scheduled for Lichtenstein hernia surgery under spinal anaesthesia, were randomly allocated to three groups. The surgical area was infiltrated with 10 mL of 0.5% bupivacaine in group 1, or 10 mL of 0.5% bupivacaine with 0.5 mg neostigmine in group 2. Patients in the control group did not receive local infiltration. Postoperative pain was assessed using a numerical rating scale (NRS), and adjective rating scale (ARS) and the need for rescue analgesia (ketoprofen or pethidine) was recorded.

RESULTS: The patients of group 1 required rescue analgesia significantly later, compared to the other two groups. Intense pain occurred less frequently in group 1 and the most frequently in group 3. The need for rescue analgesia was also least in group 1 and greatest in group 3.

CONCLUSIONS: Neostigmine added to bupivacaine had no effect on analgesia after pre-emptive local wound infiltration.