Transient Femoral Nerve Palsy Complicating “Blind” Transversus Abdominis Plane Block

Abstract

We present two cases of patients who reported quadriceps femoris weakness and hypoesthesia over the anterior thigh after an inguinal hernia repair under transversus abdominis plane (TAP) block. Transient femoral nerve palsy is the result of local anesthetic incorrectly injected between transversus abdominis muscle and transversalis fascia and pooling around the femoral nerve. Although it is a minor and self-limiting complication, it requires overnight hospital stay and observation of the patients. Performing the block under ultrasound guidance and injecting the least volume of local anesthetic required are ways of minimizing its incidence.

Femoral Nerve Palsy Following Landmark Based Ilioinguinal-Iliohypogastric Nerve Block: Case Report and Safety Review

“…Though the incidence of FNP following II/IH-NB is an uncommon occurrence, it does represent a potential risk to patient safety. Though there were no significant safety events in this case, there are reports of patient falls resulting in significant injuries including ankle sprains, ankle fractures, and femoral neck fractures [12,17,18]. This risk is increased in the elderly, and those with baseline ataxia or neuromuscular disorders.…”

“…Complications following II/IH-NB are 4.5-9% [3, 9, 12] with serious complications rarely reported. In addition to transient FNP, complications include trauma to blood vessels, pelvic hematoma, intravascular injection, urinary retention, and bladder/enteric penetration [3,5,9,12]. Practitioner experience and modality of administration have been associated with complications and failure of NB to provide adequate analgesia [5,13].…”

Transient abdominal motor block after a transversus abdominis plane block in an elderly patient

“…[1][2][3] In two such case reports of transient motor weakness from a TAP block, one describes two adults with femoral nerve impairment, 2 and another depicts an abdominal wall muscle impairment in a child. 3 Untoward motor effects as well as failures of TAP block have been ascribed to imprecision in needle placement and to tracking the local anesthetic caudad.…”

“…3 Untoward motor effects as well as failures of TAP block have been ascribed to imprecision in needle placement and to tracking the local anesthetic caudad. 2,3 Ultrasound techniques should minimize such occurrences. In our case, the bulge was mid-abdominal, which suggests that the local anesthetic can spread cephalad at relatively high doses and volumes even when it is injected under ultrasound guidance.…”

Morphometric study of the triangle of Petit in human fetuses

“…TAP is located in the anterior abdominal wall between the transversus abdominis and the internal oblique muscle, and includes the lower intercostal nerves with concomitant blood vessels destined for the anterolateral abdominal wall. [6][7][8][9] To date, autopsy material of adult individuals only has been used for the geometrical analysis of Petit's triangle. 6,7,10 Therefore, this is the first report in the professional literature to present a numerical analysis of Petit's triangle in human fetuses.…”