172 Ultrasound guided combined sciatic plus femoral nerve block in high risk patients posted for lower limb surgeries

Ultrasound guided sciatic nerve blockade – subgluteal and popliteal approaches

“…It is formed in the pelvis from the anterior rami of spinal nerves L4 to S3. It exits the pelvis via the greater sciatic foramen, directly below the piriformis and then travels in the posterior compartment of the thigh and subdivides into common peroneal nerve (CPN) and tibial nerve (TN), usually at the upper angle of the popliteal fossa [10]. In 8% of cases, high division of the sciatic nerve occurs within the pelvis and not after it exits the pelvis.…”

“…Sciatic nerve blocks provide both analgesia and anaesthesia for below knee surgery, knee surgery involving the posterior compartment and foot and ankle surgery [13]. They can be used alone or in combination with ipsilateral lumbar plexus blockade or femoral nerve blockade to provide surgical anaesthesia or analgesia to the entire lower limb [10,13].…”

“…As part of enhanced recovery pathways, sciatic nerve blocks facilitate ambulatory surgery, where there is evidence to suggest that they reduce opioid consumption [9]. They can be used in combination with femoral and obturator nerve block for anaesthesia in high-risk patients undergoing lower limb surgery and so offer an alternative to general anaesthesia in this vulnerable group [10].…”

“…The introduction of ultrasound has allowed for more streamlined and targeted approach at multiple points along its course, tailored to each individual case. This is particularly useful where there is obesity or the presence of external fixation devices which prevent identification of key landmarks [10]. Moreover, the sciatic nerve is subject to significant anatomical variation of up to 15% and thus ultrasound is a superior technique than landmark in these instances [11,12].…”