The patient an Iraqi citizen came to the clinic 28-May-2023 with LBP for 1 month and left sciatica for 6 months and difficult walking and numbness both feet. MRI done 13-May-2023 showing severe lumbar canal stenosis L2-3 with transpedicular screws at L3,4 and L5. The patient is hypertensive for 15 years in medication and had lumbar fixation of L3-4-5, 9 years ago and total knee replacement right 4 years ago and left 5 years ago.

On examination, the patient is in pain, limping with exaggerated scoliotic stance and walking bended anterior. SLRS was 50 degrees both sides with pain more in the left side. There is weak dorsiflexion both feet 4/5, more weak at the left foot- -4/5.

The patient was sent for investigations and MRI lumbar spine showed severe lumbar canal stenosis L2-3 and transpedicular fixation at L3-4-5, MRI cervical spine showed bulge C4-5, 5-6, 6-7 and C7-D1, dynamic studies ruled out overmobility. CT-scan of L1-S1 with ORS Visual showed the left L5 screw inside the canal.  Lab investigations repeated 25-March-2023 showed still high ESR 64 mm/h.

Decompressive laminectomy L2 and L3 with foraminotomy both L3 roots with inspection of the annulus fibrosis of L2-3. It was decided not to violate the disc because there is no extrusion. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak.  Exposure of the construct and the rods were removed for more bending to accept the natural curve of the area. Using MultiGen, the rods were not responding to monopolar stimulation of 5 Volts, except the left lower screw, which showed brisk reaction. The left L5 screw was removed and new Legacy Medtronic screw repositioned more laterally to go inside the pedicle. New rods were inserted and cross connector was applied. Routine closure of the wound. The power of both feet normalized. She was sent to the ward.

Too early now.

The patient has several problems which needs correction.

This is the 259th case using the MultiGen. This procedure regained routine acceptance.  It became a usual part of the spine and peripheral nerves surgery. Click here for reference.

Monopolar stimulation is a good practice to know if the screw is near the root.

With accumulation of data, it became clear that the irritated nerve with aberrant currents running in the C fibers up, not only causing no change or elevation of the required voltage to achieve motor response, but they could cause the preoperative weakness. Ablation of such currents results in facilitation of the motor response and improvement of function with disappearance of pain.

It is unclear why the roots have several motor response with different patients, despite the fact that the neurological status was the same and the anesthesia protocol also the same.

It could be that the nerve is recovering minute by minute after decompression and this can explain why the motor conductivity is improving after the BPRF application, which require 5 minute session in most cases.

After the 172d case, the elevation of motor stimulation above 5 V was abandoned to avoid delayed dural tear with subsequent CSF leak, which take place at the contact at the lower electrode shaft with the dura below or above the level of the axilla.

Before doing motor stimulation in peripheral nerve surgery with tourniquet. always remove the tourniquet before performing motor stimulation.