Low-dose bupivacaine spinal anaesthesia for percutaneous nephrolithotomy: the suitability and impact of adding intrathecal fentanyl

BACKGROUND: Unilateral spinal anaesthesia has been used for lower limb surgery with a stable cardiovascular state and a short recovery unit stay. We sought to test the suitability of low-dose bupivacaine spinal anaesthesia for percutaneous nephrolithotomy, a procedure hitherto performed under general anaesthesia. Furthermore, we hypothesized that adding intrathecal fentanyl to bupivacaine may improve the quality of anaesthesia. METHODS: We randomly allocated, through computer-generated randomization, 108 patients subjected to percutaneous nephrolithotomy to receive either 7.5 mg of hyperbaric bupivacaine 5 mg/ml alone or with the addition of 10 microg of fentanyl. Drugs were given at the L(2)-L(3) interspace with the patient in the lateral decubitus position. The patients remained in this position for 10 min, after which the sensory and motor blocks were assessed. Intra-operative analgesic supplementation, when deemed necessary, was achieved with intravenous fentanyl boluses (25 microg). RESULTS: The sensory and motor blocks after intrathecal bupivacaine and bupivacaine-fentanyl were similar. Sensory block, in both groups, reached the fifth and eighth thoracic dermatomes on the operative and non-operative sides, respectively. Deep motor block occurred on the operative side in all patients and in nearly 50% of patients on the non-operative side. The patients in the bupivacaine-fentanyl group required less intra-operative and post-operative analgesics, and both patients and endoscopists were better satisfied. CONCLUSION: This study demonstrated, for the first time, that intrathecal low-dose bupivacaine and fentanyl offers a reliable neuraxial block for patients subjected to percutaneous nephrolithotomy, with stable haemodynamics, good post-operative analgesia and acceptable patient and endoscopist satisfaction.