The patient came was operated by me 15-March-2017 for extruded disc L5-S1 with left downward migration, then 23-March-2017 for recurrence. The patient then came 18-March-2023 with agonizing right sciatic for 6 days. MRI lumbar spine showed recurrence of L5-S1 with right far downward migration.

On examination, the patient is in agonizing pain, in wheelchair. SLRS was 40 degrees right side with pain and 80 degrees left side without pain. There is weak dorsiflexion right foot 4/5.

The patient was sent for investigations and CRP was 5.3 mg/dL. ESR was 25 mm/h. The patient was advised to start antibiotic.

Extended right S1 foraminotomy with right sided removal of the extrusion lateral to the axilla and right sided cleaning L5-S1 disc space. Subaxillary inspection for remnants was negative. Using MultiGen, bipolar stimulation of the right S1 root was responding to 1.6 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the right S1 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar stimulation of the right S1 root was responding to 1.6 Volts. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. Routine closure of the wound. The power of the right foot normalized. She was sent to the ward.

Too early now.

The recurrence rate here is below 7%, because the disc space is shallow.

This is the 255th 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 is 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 did not change to motor stimulation after performed BPRF, because it was in good shape.

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.