A 50 year old man with no pertinent past medical history presents with pain in the left hip after a fall from a ladder. His vitals signs are within normal limits. On examination, he has a shortened and externally rotated left leg with intact sensation and pulses. The AP Pelvic x-ray is seen below:
You are asked to assess him with bedside ultrasound to perform ultrasound-guided regional anesthesia for pain control. Which ultrasound-guided nerve block is best suited for this type of injury?
Suprainguinal Fascia Iliaca Block (SIFI)
The bedside ultrasound images demonstrate the suprainguinal fascia iliaca (SIFI) block. A linear probe is used and an echogenic needle is directly visualized in long axis. The needle enters the skin at the inferior aspect of the probe, underneath the inguinal ligament. It traverses cephalad through the sartorius muslce to the space between the fascia iliaca and iliacus muscle inferior to the internal oblique. After negative aspiration and confirmation by hydrodissection with sterile water, 40cc of a 1:1 ratio mixture of 0.5% bupivacaine and sterile saline was utilized. The patient reported improved pain control after the procedure and was admitted for an ORIF with the orthopedics team. (Click here for the 5 Minute Sono Tutorial)
The ultrasound guided suprainguinal fascia iliaca block is an effective technique to provide anesthesia to the hip, medial thigh and knee by targeting the femoral, lateral femoral cutaneous and obturator nerves.
Compared to the infrainguinal approach, the suprainguinal approach is able to target nerves more proximally from their origin from the lumbar plexus and allow for more consistent anesthesia of the obturator nerve1.
Using a high-frequency linear ultrasound probe, find the tapered confluence of the internal oblique and sartorius at the inguinal ligament or “bow tie”. Place the probe on the Anterior Superior Iliac Spine (ASIS) in a parasagittal orientation.
Slide the probe medially and inferiorly along the inguinal crease until the sartorius and internal oblique are into view, usually within the first third of the distance from the ASIS to the pubic tubercle. A slight rotation of the probe toward the umbilicus improves visualization.
The needle is inserted at the skin underneath the inguinal ligament, traversing through the sartorius muscle or underneath it to pierce the fascia iliaca inferior to the internal oblique. The deep circumflex iliac artery can be identified between the internal oblique and fascia iliaca and serves as an important landmark and structure to avoid.
In general, 40 ml of volume is sufficient to open the potential space and provide adequate anesthesia3.
Vermeylen K, Soetens F, Leunen I, et al. The effect of the volume of supra-inguinal injected solution on the spread of the injectate under the fascia iliaca: a preliminary study. J Anesth. 2018;32(6):908-913. doi:10.1007/s00540-018-2558