Comparison of ultrasound guided supine (crosswise approach to popliteal sciatic nerve- CAPS) and lateral approaches to popliteal sciatic nerve block for below knee surgeries

The popliteal sciatic nerve block (PSNB) is a commonly practiced regional anesthesia technique well-suited to provide anesthesia or analgesia for below-knee surgeries. The ultrasound guided PSNB is usually performed in the prone or lateral position. However, in various conditions such as spine injury, morbid obesity, hemodynamic instability and pregnancy it may not be feasible to position the patient in a prone or lateral  position. Improper positioning may then lead to an inadequate or failed block. This may require conversion to spinal or general anesthesia which is usually not ideal as it increases the possibility of hemodynamic fluctuations. Therefore, in our study we will be comparing the lateral approach and supine approach in giving the PSNB. Supine position will eliminate the difficulties faced in other positions for the patient and the anesthetist. We expect the supine approach to be just as easy, effective  and safe method of providing PSNB.