[Tomographic identification of popliteal nerves epineural sheath during foot intermittent regional anesthesia: case...

Lower limb regional nervous blocks are common procedures for surgery and postoperative analgesia. This study aimed at describing a rare and casual tomographic image of a catheter in the popliteal fossa, which was originally directed to the sciatic nerve, and of anesthetic solution spread during intermittent analgesia for foot trauma.

Male patient, 54 years old, physical status ASA III, with severe left foot trauma and submitted to sciatic nerve block through a catheter inserted in the apex of the popliteal triangle. Since 10 ml injections of 0.375% bupivacaine with epinephrine 1:400,000 allowed for daily dressings and débridement while preserving plantar sensitivity, the phenomenon was radiologically investigated. Enhanced radiographic and tomographic studies of the popliteal region were able to show catheter positioning and anesthetic spread under the sheath of each component of the sciatic nerve.

Relevant enhanced tomographic findings of the popliteal region have proven a recent anatomic study on the individualization of the neural sheath involving popliteal nerves with implications in blockade outcome. Anesthesia obtained by a catheter in the popliteal fossa was effective only in the superficial fibular nerve dermatome (medial dorsum of foot and hallux).