The obturator kick

Ask the room

You are doing this case. Where is the danger, and what is your first move if it happens?

Take answers before advancing. The point of the debrief is what they say now, not what the next slide says.

• The obturator nerve runs immediately deep to the lateral wall, just millimetres beyond the tumour.
• Monopolar current spreads through the detrusor and stimulates it directly, with no contact needed.
• The result is a violent adductor contraction that can drive the loop clean through the wall.

resectoscope view

1. Examine under anaesthetic: bimanual palpation for a mass and for fixity, recorded before and after resection.
2. Pass the resectoscope under vision and perform a systematic cystoscopy of the whole bladder, noting every tumour, its site, size and configuration.
3. Identify both ureteric orifices and the relation of each tumour to them before resecting, so an orifice is not undermined.
4. Resect the exophytic tumour in layers, working from the surface down, keeping the bladder comfortably but not tightly filled.
5. Take the tumour base separately and send it as a distinct specimen, resecting deep enough to include detrusor muscle for accurate staging.
6. Obtain haemostasis as you go and inspect the resection bed, then any suspicious flat areas, with biopsies as indicated.
7. Empty the bladder, confirm the wall is intact, and leave a catheter with irrigation as the case dictates.

• The obturator nerve runs along the pelvic side wall, immediately deep to the inferolateral bladder.
• It never has to be touched to fire.
• During resection of a lateral wall tumour, monopolar diathermy current spreads through the detrusor and stimulates the nerve directly.
• The thigh adductors contract in a single violent jerk - the kick - driving the resectoscope deeper than intended.
• The danger is not the cut you meant to make, but the one the leg makes for you: a deep muscle resection or a full-thickness perforation.

• lateral / inferolateral tumour
• overdistended thin bladder
• monopolar energy
• large tumour base

1. Come off the pedal the instant a kick occurs or is anticipated. Stop resecting.
2. Partially empty the bladder. A thicker, less distended wall puts distance between loop and nerve.
3. Drop the cutting current and resect in short, tangential bursts rather than deep sweeps.
4. If you are on bipolar, you are already on the safer energy. If on monopolar and the resection cannot wait, plan to complete the lateral wall on bipolar; it lowers but does not abolish the reflex.
5. Ask anaesthetics to deepen neuromuscular blockade for continued lateral wall work. It usually prevents the kick but does not abolish it reliably: contraction has been recorded even at complete block, so plan an obturator nerve block for high-risk work.
6. Request an obturator nerve block for a recurrent reflex or high-risk lateral wall work; it reduces the reflex more reliably than deep blockade alone.
7. Inspect for perforation after any forceful kick. Extraperitoneal: catheter and observe. Intraperitoneal or large defect: this is your conversion trigger. Document the kick, the assessment, and the plan in the op note. escalation trigger

Three questions

1. If the nerve is still being stimulated, how does paralysis stop the kick?
2. How do you distinguish extraperitoneal from intraperitoneal perforation?
3. Why might bipolar reduce the reflex compared with monopolar?

Answers are on the card under the viva section. Hold them back until everyone has tried.

• Anyone can say 'stop and put a catheter in'.
• The strong answer names deep neuromuscular blockade and an obturator nerve block as the preventions, explains why paralysis works despite continued nerve stimulation and why it is not absolute, and separates extraperitoneal from intraperitoneal perforation in both diagnosis and management.