The patient came to the clinic 09-September-2019 complaining of LBP for 7 years with left agonizing sciatica for 3 months with numbness all toes left foot. MRI lumbar spine performed 20-August-2019, bad quality, showing huge extruded disc L4-5 more to the left with downward migration.

On examination: She is in agonizing pain, not limping with exaggerated scoliotic stance. SLRS was 50 degrees right side with pain shooting to the left and 60 degrees in the left without pain. There was weak dorsiflexion left foot -3/5, dorsiflexion right foot 4/5.

The patient was sent for investigations: MRI lumbar spine performed 09-September-2019 showing wide-based extruded disc L4-5 with left downward migration. Dynamic studies ruled out overmobility. Lab investigations were uneventful. The patient was advised for surgery.

Left L4-5 foraminotomy. All the compressive elements were drilled out and inspection of the disc showed extruded disc L4-5 with severe compression of the left L5. The extruded huge disc was removed in several pieces and the disc space was cleaned. Extended foraminotomy of the left L5 roots was achieved.  Using MultiGen, bipolar motor stimulation of the left L5 root was achieved with 0.9 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the left L5 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the left L5 root was achieved even with 0.7 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 both feet normalized and the sciatica disappeared. She was sent to the ward.

The estimated recurrence rate is around 7%, despite the fact that the disc space is slightly shallow.

This is the 184th 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 severely affected nerves improved dramatically 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.