This study is designed as a randomized controlled trial aiming to evaluate the feasibility and safety of ultrasound-guided mid-femoral lateral approach sciatic nerve paraneural sheath block, in order to provide a new sciatic nerve block approach for clinical practice that offers greater patient comfort and higher precision, thereby facilitating its use for specific patient populations and less experienced operators.
Patients scheduled for elective unilateral surgery below the knee (e.g., internal fixation for ankle, metatarsal, or calcaneal fractures; hallux valgus correction; flatfoot reconstruction).
American Society of Anesthesiologists (ASA) physical status class I or II.
Aged 18 to 65 years.
Ability to understand the study procedure and provide written informed consent.
Known allergy or history of toxicity to local anesthetics.
Pre-existing neuropathy in the operative limb.
Severe coagulopathy.
Infection at the intended needle puncture site.