Paravertebral block in inguinal hernia surgeries: two segments or 4 segments?

In this study, we compare paravertebral block (PVB) of the T10 and L1 segments and multiple-segment PVB for anesthesia and analgesia in inguinal hernia surgeries.

Anatomic study was performed on 3 cadavers. A 15-mL methylene blue solution was injected at the T10 level and then an additional 5-mL dye injection at L1 level. Fifty patients were included in the study. Patients in group 1 (n = 25) underwent PVB of 2 segments at the T10 and L1 vertebrae levels on the same side as the hernia, whereas patients in group 2 (n = 25) underwent PVB through 4 segments at T10, T11, T12, and L1 on the same side as the hernia. Perioperative propofol/remifentanil consumption, surgery start time, time to perform the block, duration of sensory block, postoperative visual analog scale scores, and complications were evaluated.

Any passage down to the T12 level was not observed after injection at the T10 level and also only after additional 5-mL dye injection at the L1 level; the genitofemoral, ilioinguinal, iliohypogastric, and lateral femoral cutaneous nerves were stained with dye in cadavers. The times for block application were 5 mins (SD, 1 min) in group 1 and 16 mins (SD, 4 mins) in group 2 (P < 0.001). The surgery start time was 25 mins (SD, 3 mins) in group 1 and 27 mins (SD, 6 mins) in group 2 (P = 0.234). In both groups, propofol and remifentanil were used in similar quantities during the perioperative period. Use of paracetamol tablets was similar in both groups (P > 0.05). Whereas none of the patients in group 1 displayed motor block or contralateral spread, 2 patients in group 2 displayed contralateral spread, and motor block was observed in 1 patient. Twenty-three patients (92%) in group 1 and 24 patients (96%) in group 2 were satisfied with the method (P > 0.05).

Two-segment PVB can be an alternative to 4-segment PVB in inguinal hernia surgeries. Decreasing the number of injections required in this technique may further increase patient comfort and decrease complications.