A randomized prospective comparative study of nerve stimulator and ultrasonogram in popliteal sciatic nerve block for ankle and foot surgeries.

Background: Regional blocks in the field of anaesthesia were done traditionally with paraesthesia technique. To overcome the demerits with paraesthesia technique, nerve locator was applied for nerve blocks. Later, the application of ultrasonogram for regional blocks got the real time imaging of the nerves and drug administration. This resulted in publications of numerous studies with variable results. Therefore we planned to compare ultrasonogram and nerve locator in popliteal sciatic nerve block in our population. Methods: A prospective, randomized, observer blinded study was planned to compare the nerve stimulator (Group N) and ultrasound (Group U) on duration of „block technique‟, number of needle reinsertions in popliteal sciatic nerve block for ankle and foot surgeries. We included all consented patients aged ≥18 years of both genders belonging to ASA I to III and excluded pregnant mothers, diabetes mellitus, neuropathy, chronic opioid use, positioning difficulty, coagulopathy, nerve block contraindications, local anaesthetic allergic patients. Results: The duration of block technique in Group U = 262.00 ± 108.36 Seconds and Group N = 715.16 ± 234.66 Seconds with statistically significant P value = 0.0001. The average number of needle reinsertions in Group N = 6.05 ± 2.31 and Group U = 2.46 ± 1.11 with statistically significant p value of 0.0001. Therefore the time taken to perform the block and the number of needle reinsertions in Group U is shorter than the Group N. Conclusion: The duration of block technique and number of needle reinsertions are better with ultrasound. Though the onset of motor and sensory blockade were better with ultrasound success rate is not significantly different.