The course of the sciatic nerve in the gluteal region and comparison of two methods used for sciatic nerve blockage

Objectives: The aim of this study was to reevaluate the anatomy of the sciatic nerve (SN) in the gluteal region by identifying reliable landmarks in order to suggest a safe insertion point for SN blockage (SNB), and to compare two methods used for SNB. Methods: Bilateral dissections of the SN were performed on ten embalmed cadavers. The course of the SN in relation to a line drawn between the posterior superior iliac spine (PSIS) and the ischial tuberosity (IT) was determined. The files of 100 patients, 50 of whom had SNB with the Labat’s method (group L) and 50 with the parasacral approach (group P), were reviewed retrospectively. The results of the two methods were compared. Results: The vertical distance between the PSIS to the IT was 13.1±6.5cm. The vertical distance between the intersection points of the inferior border of the piriformis with the medial and lateral margins of the SN were 7.8±0.7 and 9.1±0.6 cm, respectively. Medial and lateral margins of the SN were found to be 1.8±0.5 and 2.9±0.6 cm lateral to the IT. Insertion depth of the needle and time for the intervention were similar for both of the methods, but need for additional nerve blockages were significantly higher in group L than in group P. Conclusion: We defined a safe insertion point for SNB in the gluteal region, using prominent, fixed bony and easily detectable landmarks. The clinical results of both groups were similar, but need for additional nerve blockages were significantly higher in group L.