The patient came to the clinic 22-November-2020 complaining of LBP with left sciatica for 2 months with exacerbation of left sciatica the last week down to the big toe left foot. MRI lumbar spine performed 22-Novembber-2020 showing extruded disc L4-5 with left foraminal occlusion and small old bulge L3-4 right side.

On examination: The patient is in agonizing pain, limping with exaggerated scoliotic stance. There is weak dorsiflexion left foot -4/5. SLRS was 25 degrees with pain left side.

The patient was sent for investigations and ESR was 35 mm/h and CRP 12 mg/L. The patient was advised to start Zinnat 500 mg twice daily before the surgery.

Extended left L5 foraminotomy with removal of the extrusion and left sided intradiscal cleaning of L4-5.  Using MultiGen, bipolar motor stimulation of the left L5 root was achieved with 2.4 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 with 1.8 Volt. 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 improved. She was sent to the ward.

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

This is the 203d 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 motor stimulation of the severely affected nerve improved.

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.