Ultrasound-guided ilioinguinal and iliohypogastric nerve block, a comparison with the conventional technique: An observational study

BACKGROUND: The conventional technique of ilioinguinal and iliohypogastric nerve block may be associated with drug toxicity, block failure and needs large drug volume. The ultrasound-guided (USG) nerve block enables accurate needle positioning that may reduce the chances of drug toxicity, drug dose and block failure. AIM: In this study, we compared the onset and duration of the motor and sensory nerve block, the drug volume required and time to rescue analgesic between USG and conventional technique. SETTINGS AND DESIGN: Sixty male patients aged between 18 and 60 years, belonging to American society of Anesthesiology I-II, scheduled for inguinal hernia repair were enrolled in this prospective study and were randomly allocated into two groups of thirty each by computerized method. MATERIALS AND METHODS: Group A patients received hernia block by conventional method using 0.75% ropivacaine 15 ml, and Group B patients were given the block guided by ultrasound using 0.75% ropivacaine, till the nerves were surrounded on all sides by the drug. STATISTICAL ANALYSIS: The data were analyzed using two independent sample t-tests for demographic and hemodynamic parameters. Nonparametric test (Mann-Whitney U-test) was used to find the significance between visual analog scale. RESULTS: There was significantly early onset of sensory block in Group B 14.03 ± 2.82 min as compared to Group A 15.57 ± 1.52 min (P = 0.047). The onset of motor block was also earlier in Group B 19.40 ± 2.85 min as compared to Group A 20.67 ± 1.90 min. The time to rescue analgesia was more in Group B 7.22 ± 0.97 h as compared to Group A 6.80 ± 0.70 h (P = 0.062). The volume of drug required was less with ultrasound guided block. CONCLUSIONS: Ultrasound-guided hernia block thus has the advantage of early onset, less dose requirement and increase in time to rescue analgesia.