The patient came to the clinic 25-October-2021 complaining of LBP for 20 days with left sciatica with numbness left foot. MRI lumbar spine done 16-October-2021 showing central extruded disc L3-4 with left downward migration. Dynamic studies ruled out overmobility. The patient is a known hypertensive for 8 years under treatment.

On examination, the patient in agonizing pain, limping with exaggerated scoliotic stance. SLRS 30 degrees both side with pain more the left side. There is weak dorsiflexion both feet 4/5.

The patient was sent for lab and cardio evaluation.

The level of L3-4 was identified by the C-arm. Foraminotomy left L4 root with removal of the extrusion lateral to the axilla and left sided cleaning of L3-4 disc space. Using MultiGen, bipolar stimulation of the left L4 root was achieved with 1.8 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the left L4 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar stimulation of the left L4 root was achieved with 1.4 Volts. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. A fat tissue with pedicle was used to cover the dura to minimize the postoperative scar formation and prevent postoperative CSF leak. Routine closure of the wound. Smooth postoperative recovery. The power of the feet improved. She was sent to the ward.

Too early now.

This is the 228th 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 affected nerve showed improvement 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.