Clinical-Radiological Correlation of Ultrasound Guided Dorsal Sacral Foramen Injection for Foot and Ankle Surgeries - A Case Report
Popliteal sciatic nerve block, supplemented by either a femoral nerve or an adductor canal block is the commonly used peripheral nerve block technique for foot and ankle surgeries. Dorsal sacral foramen injection (DSFI) can be an alternative, as it has the potential to block the presacral nerve roots and the sciatic nerve. We present a series of five patients scheduled for foot and ankle surgery, who received spinal anaesthesia as the primary anaesthetic and ultrasound guided DSFI at the level of second sacral foramina for postoperative analgesia. Two patients of subtalar arthrosis received an additional adductor canal block as the incision involved medial part of the foot, innervated by the saphenous nerve. While performing the DSFI, needle tip was confirmed with fluoroscopy and radio-contrast was injected to reveal the spread. Postoperatively computerised tomography (CT) scan was performed on all five patients. Fluoroscopy and CT scan confirmed a spread in the epidural space and along the roots of the sacral plexus, which possibly is the mechanism of analgesia in lower limb surgical procedures. Clinically, all the patients remained pain free till 6 hrs following the block. The time to first analgesic were 11, 14, 8, 10 and 16 hours respectively.