Transversal ultrasound-guided approach to the popliteal ssciatic nerve block in the supine position: feasibility, effectiveness, and safety in lower-limb surgery
Mario Germán Orozco Sandoval, Miguel A. Pinzon, Harold A. Sandoval, Edwin A. Guarnizo, Luis F. Lasso, Andres F. Velasquez, Natalia EscobarAbstract
Background
The popliteal sciatic nerve block is an established technique to provide anesthesia and analgesia for surgical procedures below the knee. Classical approaches require the prone or lateral position, which can be uncomfortable for the patient, demand additional personnel, and entail risks in patients under general anesthesia. Ultrasound guidance has enabled the development of alternative techniques such as the transversal approach in the supine position, which may optimize logistics and patient comfort without compromising effectiveness or safety.
Methods
We conducted an observational, descriptive, cross-sectional study between September and December 2024 at Fundación San José de Buga (Colombia). Adult patients undergoing lower limb surgery under ultrasound-guided popliteal sciatic nerve block using a transversal approach were included. Sociodemographic, clinical, surgical, and technical variables were recorded, along with associated medications, operator subjective evaluation, analgesic effectiveness (VAS at different time points), and safety (immediate and 24-h adverse events). The analysis included descriptive and bivariate statistics according to the technique used, with a significance level set at p<0.05.
Results
Data from 50 patients were analyzed. The median age was 58.5 years (IQR, 41–69), with male predominance (66 %). Ninety-four percent received a block via the transversal technique, achieving an optimal ultrasound window in all cases and without the need for additional mobilization. The median depth of the sciatic nerve was 3.5 cm (IQR, 3.0–4.0). The anesthetic volume used was 15 mL of levobupivacaine in all cases. The transversal approach was highly rated by operators: 94 % considered it comfortable, easy to perform, and associated with excellent image quality. Analgesia was effective, with VAS 0 in 100 % of patients immediately postoperatively and at 6 h, and in 90 % at 24 h; no patient required rescue analgesia or opioids. No cardiovascular or respiratory adverse events, or immediate or 24-h complications, were reported.
Conclusions
The ultrasound-guided transversal approach to the popliteal sciatic nerve block in the supine position is a feasible, safe, and effective technique that provides logistical and comfort advantages for both patient and operator. Its safety and efficacy profile make it an attractive alternative to classical approaches, particularly in scenarios where patient mobilization is limited or risky. Future comparative studies with larger sample sizes are needed to confirm these findings and assess its applicability in ambulatory surgery.