Obturator jerk reflex

A serious complication of Transurethral bladder resection is bladder perforation, the risk of which is greatly increased in the presence of an “obturator jerk”.

An obturator jerk during TURBT greatly increases the risk of bladder perforation.

The commonest site of bladder perforation is the lateral wall, during TURBT for tumors at this site.

Electrical stimulation of the proximate obturator nerve during electroresection of lateral wall tumors can result in a powerful adductor spasm of the leg known as an “obturator jerk”

Measures to reduce the likelihood of an obturator jerk include reducing the diathermy current, avoiding over-distending the bladder, and using bipolar diathermy as opposed to monopolar diathermy.

The use of neuromuscular blockade or an obturator nerve block to reduce the incidence of obturator jerk and risk of bladder perforation.

The obturator nerve is a mixed nerve with motor and sensory fibers, arising from the anterior primary rami of L2, L3 and L4 in the lumbar plexus.

The obturator nerve descends within the psoas major muscle, before emerging from the inner border of the muscle in the abdomen.

It then travels with the lumbosacral trunk, crossing into the pelvis at the level of the sacroiliac joint (L5) under the common iliac artery and vein, and runs anterior/lateral to the ureter.

It passes close to the wall of the bladder on its inferior/lateral portion, and then takes place anterior to the obturator vessels within the superior part of the obturator foramen.

It exits the pelvis below the superior pubic ramus, passing through the obturator canal before entering the adductor region of the thigh.

The nerve divides into anterior and posterior branches.

The anterior division of the nerve enters the medial compartment of the thigh and gives off branches which innervate adductor brevis, adductor longus and gracilis, as well as branches which supply sensation to the skin along the mid-portion of the medial thigh.

Branches of the posterior division innervate both the obturator externus and adductor magnus muscles.

Reducing the diathermy current used during resection reduces the risk of obturator jerk.

Using bi-polar diathermy currently is accepted as to leading to a lower risk of obturator jerk, although some studies fail to demonstrate such findings.

Avoiding overfilling of the bladder during TURBT reduces the risk of obturator nerve stimulation, as a distended bladder brings the lateral bladder wall closer to the obturator nerve.

TURBT can be performed under general anesthesia or regional anesthesia.

Spinal block does not inhibit the obturator jerk.

Techniques employed to reduce the risk of obturator jerk include:

use of neuromuscular blockade, with general anesthesia, often with an endotracheal tube to secure the airway

selective blockade of the obturator nerve

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