The patient came to the clinic 10-October-2019 complaining of LBP for 2 months. Left sciatica the last 25 days. MRI lumbar spine performed 09-September-2019, showing huge extruded disc L4-5 more to the left.

On examination: He is limping with exaggerated scoliotic stance. SLRS was 75 degrees left side with shooting pain. There was weak dorsiflexion left foot -3/5.

The patient was sent for investigations: MRI lumbar spine done 10-October-2019 showed the same extrusion.

Left L5 foraminotomy with reflection of ligamentum flavum to the right. Removal of the extrusion and left sided cleaning L4-5 disc space. Using MultiGen, bipolar motor stimulation of the left L5 root was achieved with 1.1 Volts. 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 0.9 Volts. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. Routine closure of the wound.

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

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

This is the 188th 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.