Ultrasound-guided popliteal sciatic and adductor canal block for below-knee surgeries in high-risk patients

Central neuraxial block and general anaesthesia in patients with significant comorbidities are associated with considerable peri-operative morbidity and mortality. This study aims to delineate peripheral nerve block as a suitable alternative technique in high-risk patients posted for below-knee surgery.

Twenty patients with the American Society of Anesthesiologist's (ASA) physical status grade III and IV, aged 30-80 years, scheduled for below-knee surgery from May 2018 to February 2019 were enrolled in this prospective study. All patients received ultrasound-guided popliteal sciatic block with 20 ml 0.5% ropivacaine and adductor canal block with 10 ml 0.375% ropivacaine. The peripheral nerve block success rate, sensory and motor block onset time, haemodynamic parameters, duration of post-operative analgesia and patient's satisfaction were recorded. Descriptive statistics of the study were calculated and the data was analysed using an SPSS statistics 21.0 program.

Surgery was performed successfully with no additional analgesic requirement in all patients. The mean duration for sensory and motor block onset time was 3.35 ± 0.49 (mean ± standard deviation) and 4.65 ± 0.48 (mean ± standard deviation) minutes respectively. Haemodynamic parameters were maintained stable throughout the procedure. The average duration of postoperative analgesia was 7.5 ± 0.8 (mean ± standard deviation) hours. Patient overall satisfaction as assessed, by three-point Lickert's scale, was satisfactory.

Ultrasound-guided combined popliteal sciatic and adductor canal block is an effective alternative anaesthetic technique for below-knee surgeries with stability of haemodynamic parameters and pain management in high-risk patients.