The patient came to the clinic 13-October-2018 complaining of LBP with right sciatica for 4 months with inability to stand more than 3 minutes. MRI lumbar spine performed 09-September-2018 showing extruded disc L4-5 with right foraminal occlusion. The patient is a known diabetic with arterial hypertension for 10 years in medications. Cath was done and 2 stents were applied. In plavix  and using Omnic for hypertrophy of prostate.

On examination: He is not limping, but has scoliotic stance. SLRS was 70 degrees right side with pain and 80 degrees in the left without pain. There was weak dorsiflexion right foot 4/5.

The patient was sent for investigations and MRI performed 14-October-2018 showing extruded disc L4-5 wide based more to the right with severe segmental stenosis. Dynamic studies ruled out overmobility. The patient was sent for cardiac evaluation. The patient repeated MRI lumbar spine 30-January-2019 confirming the previous data and telling that his condition is deteriorating.

Decompressive laminectomy L4 and upper third of L5. Foraminotomy both L5 roots with removal of the extrusion lateral to the axilla and right sided cleaning L4-5 disc space. The dura was very thin, that it had pinpoint dural defect at the lower area of the dorsal dura and it was stitched with one stitch using 6 zero nylon. Inspection of the disc space from the left was uneventful and decided not to violate it. Using MultiGen, bipolar motor stimulation of the right L5 root was achieved with 0.4 Volts. Bipolar motor stimulation of the left L5 root was achieved with 1.2 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to both L5 roots was achieved using 4 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the right L5 root was achieved with 0.4 V with more brisk response as before. Bipolar motor stimulation of the left L5 root was achieved with 1.0 V. The patient was put in Reverse Trendelenburg position with Valsalva maneuver. No CSF leak. Routine closure of the wound.

Smooth postoperative recovery. The power of the right foot improved and the sciatica disappeared. He was sent to the ward.

There is still an estimated postoperative re-recurrence around 7%, because the disc space height is still not shallow.

This is the 174th case using the BPRF mode with MultiGen. This procedure regained routine acceptance.  It became a usual part of the spine and peripheral nerves surgery. Click here for reference.

It still unclear to evaluate the differences of pre and post application motor responses. The only sure thing that it tells that the electrodes did not migrate during the procedure and the nerve is functioning properly. Here the threshold of stimulation power of motor stimulation of the affected root was very low reaching 0.4V and was the same after BPRF. The less affected root improved after BPRF.

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 is 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 4 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 the level of the axilla.