The patient was operated by me several times and the last one was performed 24-March-2013 for recurrent extrusion L3-4 with discitis and treated accordingly. The patient then came to the clinic 08-February-2017 complaining of LBP with bilateral sciatica more the left with coldness of the left leg. On examination at that time, he was limping with scoliotic stance. SLRS was 70 degrees with pain in the right and 80 degrees with pain in the left. Dorsiflexion of the ankle joints was -4/5 right and complete drop foot left with planterflexion both feet 4/5. There was hypalgesia left L5 territory. The patient was sent for investigations and MRI lumbar spine performed 08-February-2017 showing extruded disc L2-3 with left upward migration with severe segmental stenosis at this level. Dynamic studies ruled out presence of overmobility. The patient was given admission, but he escaped. The patient then came 01-March-2018 telling that he got deterioration of his condition with difficult walking. MRI performed the same day showing the same stenosis at L2-3.

On examination, the patient is limping with scoliotic stance. SLRS was 45 degrees in the right with pain and 70 degrees in the left with pain. There was drop left foot -0/5, planterflexion same foot 4/5. The right foot dorsiflexion is 3/5 and planterflexion 4/5 with analgesia of the left L5 territory. There is weak both iliopsoas and quadriceps muscles both sides 4/5.

The patient was sent for investigations and cardio consultation and CT-scan lumbar spine done 03-March-2018 showing vacuum phenomena of L2-3 with severe stenosis at this level and dilatation of the aorta below the renal arteries with diameter 4.5 cm with calcification. The diameter of the aorta above and below is 2 cm. Dynamic studies were negative for overmobility. CRP was 29 mg/L. The patient was advised to start Zinnat 500mg twice daily immediately before surgery.

Decompressive laminectomy of L2 with remnant of L3 with foraminotomy both L2 roots. Inspection of L2-3 both sides was uneventful and it was decided not to violate it. Using MultiGen, bipolar motor stimulation of the right and left L3 roots were impossible, because the patient received muscle relaxant. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the right L3 and left L3 roots was achieved using 2 bended catheters 10 mm exposed length. Bipolar motor stimulation of the right L3 root was achieved with 3.2V. The left L3 was achieved with 4.2 V. Routine closure of the wound.

Smooth postoperative recovery. The power of the right foot became normal and the drop left foot showed noticeable improvement. He was sciatica free. He was sent to the ward.

The patient extruded disc disappeared with time, but the stenosis progressed.

This is the 145th 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 root after application was better.

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.

Drop foot  can benefit from such BPRF, if the the duration f the pathology is not long-standing. In case of long-standing drop foot the improvement is questionable. This case could be an exception, because the drop foot showed some improvement.

Muscle relaxants must be avoided during motor stimulation.