The patient came to the clinic 08-June-2017 complaining of LBP with right sciatica with exacerbation last 3 months with pain and numbness all toes right foot. MRI of the lumbar spine performed 13-March-2017 showing bulge disc L4-5 and extruded disc L5-S1 with right S1 root compression.

On examination, the patient is in agonizing pain, limping with mild scoliotic stance. SLRS was 35 degrees with pain in right side. There is weak dorsiflexion and planterflexion right foot 4/5.

The patient was sent for investigations and MRI lumbar spine performed 10-June-2017 showing the same data as before. Dynamic studies ruled out overmobility of the spine.

Foraminotomy of the right S1 root was achieved. The extruded disk was removed lateral to the axilla of the right S1 root. The epidural fat was preserved until the end of surgery. Right sided intradiscal cleaning of L5-S1 disc space was performed. The right S1 root was inspected to rule out any remnants of extrusion. Using MultiGen, bipolar motor stimulation of the right S1 was achieved with 2.3 V, which was considered unacceptable and reposioning of the electrodes, achieved properly to the running root. The same procedure repeated and bipolar motor stimulation of the right S1 was achieved with 1.4 V. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to right S1 root was achieved using 2 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the right S1 was achieved with 1.4 V. Routine closure of the wound.

Smooth postoperative recovery. The power of the right foot normalized and he was sciatica free. He was sent to the ward.

The patient still having an estimated postoperative recurrence around 7%, because the disc space is still not shallow.

This is the 122d 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 there was considerable improvement of the threshold of stimulation power of motor stimulation of the right S1 root after repositioning.

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.