The patient came to the clinic 14-August-2017 complaining of LBP with right sciatica for 3 months, then progressed to be bilateral sciatica more the right the last week down with numbness right S1 territory.

On examination, the patient is in agonizing pain, limping with exaggerated  scoliotic stance. He cannot set in chair due to pain. SLRS was 40 degrees with pain in both sides. There is weak dorsiflexion both feet 3/5 and planterflexion right foot 4/5.

The patient was sent for investigations and MRI lumbar spine performed 14-August-2017 showing very huge extrusion L5-S1 with right downward migration. Dynamic studies ruled out overmobility, but the lower border of L5 and upper border of S1 are eroded due to osteomyelitis. Lab investigations showed ESR 55 mm/h. CRP was 29 mg/L. CT-scan of the area confirmed the presence of erosion and showed fatigue fracture of both isthmi of L5 lamina. The patient was admitted urgently to surgery.

Foraminotomy of both S1 roots was achieved with preservation of the spinous processes and intra-spinous ligament to avoid increasing the possible postoperative instability. The extruded disk was removed from both sides and the material was sent for histological and CXS studies. After that Vancomycin 500 mg twice a day was immediately started. Using MultiGen, bipolar motor stimulation of the right S1 was achieved with 2.3 V. Bipolar motor stimulation of the left S1 was achieved with 1.4 V. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to both S1 roots was achieved using 4 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the right S1 was achieved with 1.7 V. Bipolar motor stimulation of the left S1 was achieved with 0.8 V. Routine closure of the wound.

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

The patient has huge extruded disc with discitis and osteomyelitis adjacent vertebrae. The cause of such event is still open and needs clarification for proper post-operative planning.

This is the 132d 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.