The patient came to the clinic 08-November-2018 complaining of LBP  for 3 years with left sciatica for 4 months with exacerbation last 3 weeks shooting down to the left ankle .

On examination: He is limping with exaggerated scoliotic stance. SLRS was 75 degrees right side with pain and 10 degrees in the left with severe pain. There was weak dorsiflexion left foot 3/5. There was hypalgesia left L5 and S1 roots.

The patient was sent for investigations and MRI lumbar spine performed 08-November-2018 showing huge extruded disc L4-5 with left downward migration and bulge L5-S1. All other investigations were within normal limits.

Foraminotomy left L5 root with removal of the extrusion lateral to the axilla and left sided cleaning L4-5 disc space. Using MultiGen, bipolar motor stimulation of the left L5 root was achieved with 1.1 V. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to left L5 root was achieved using 2 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the left L5 root was achieved 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 left foot became normal. He was sciatica free. He was sent to the ward.

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

This is the 170th 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 after application improved dramatically.

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.