brought to you by the nerve stimulation experts at Neurosign

July 13, 2024

C3-C5 intradural meningioma



This young woman has a C3-C5 spinal tumour. From the scans, it occupies two thirds the spinal canal space. She has some muscle weakness and pain in her left arm, and some numbness in her left leg. It appears to be intradural and it’s clinical appearance suggests it is a meningioma.

I will be using MEPS,  SSEPS and free running EMG.

For the muscle placements, I will use trapezius for C3, deltoid for C4, hypothenar for C5, and medial gastrocnemius in the legs.

For SSEPS I am using tibial nerve stimulation at the ankles, collecting from fz cz with 150 samples at 30mA.

Good baseline on right side, baseline on left at 50% amplitude of right.

For MEPS I have corkscrew electrodes at C3 C4 over the motor cortex.

Good MEPS from right side, good MEPS from left trapezius and deltoid, no response from hypothenar or gastrocnemius at 400V.

Surgeon is performing at laminectomy from C3 to C5.

Surgeon has now exposed the spinal cord having opened the dura. Rootless can be seen (these exit the dura and combine to form the spinal nerve root) with the mass of the tumour in front of the cord.

SSEPS have disappeared but MEPS remain as at baseline.

Surgeon using CUSA to debulk tumour, no changes in MEPS,  occasional discharges from same channel on right side over 30 minutes.

Surgeon has debulked tumour sufficiently to be able to mobilise the capsule along much of its length. A single sensory nerve root let appears to be the origin of the tumour, in which case this may be a nerve root schwannoma rather than a meningioma. Specimens have been taken for a final diagnosis.

The upper pole of the tumour has been removed and the surgeon is now working on the lower pole.

MEPS on the left have dropped by 50%, baseline on the right.  Surgeon advised.  After 5 minutes, responses on the left improving slightly. Trying to stimulate as often as possible on left side, when surgeon does not have hands in the patient.

On reflection,  fall in amplitudes on left correlate with a burst of activity on left side, presumably through traction. I put this down to the surgeon working on the C4 rootlet, the origin of the tumour.

Surgeon has confirmed origin of tumour in C4 rootlet and has cut it out – patient will have some sensory deficit in the neck.

MEPS on left now less than 50% baseline.  I have increased voltage by 50V but no improvement – but remaining stable at present. Surgeon is involved with the monitoring.

Tumour is now all removed, surgeon beginning to close. I will keep  onitor ingredients to see if MEPS on left side improve.