The patient came to the clinic 14-January-2023 with LBP and left sciatica for two months with exacerbation last week with numbness all toes left foot.

On examination, the patient is in agonizing pain, limping with exaggerated scoliotic stance. SLRS was 90 degrees right side without pain and 70 degrees left side with pain. There is weak dorsiflexion left foot -4/5.

The patient was sent for investigations and MRI lumbar spine done the same day showing huge extruded disc L5-S1 with left downward migration. Dynamic studies ruled out overmobility. Lab investigations were uneventful. The patient was advised to undergo surgery, but he has final graduation exams, for what he decided to finalize them.

Left S1 foraminotomy with left sided removal of the extrusion lateral to the axilla and the seek to remove the far-downward migrating piece and left sided cleaning L5-S1 disc space. Subaxillary inspection for remnants was negative. Using MultiGen, bipolar stimulation of the left S1 root was responding to 1.1 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the left S1 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar stimulation of the left S1 root was responding to 0.8 Volts. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. The power of the left foot improved. He was sent to the ward.

Too early now.

The recurrence rate here is around 7%, because the disc space is not shallow.

This is the 251st 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. The nerve improved moderately to motor stimulation after performed 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 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.