The patient came to the clinic 05-January-2021 complaining of numbness left leg with left sciatica for 3 years with difficult walking. MRI lumbar spine performed bad quality 28-November-2020 showing LCS L4-5. EMG done 03-October-2020 not informative

On examination: The patient is limping with exaggerated scoliotic stance. There is weak dorsiflexion left foot -4/5 with hypalgesia and numbness below the left knee.

The patient was sent for investigations and MRI lumbar spine performed 05-January-2021, showing severe LCS L4-5 and less at L3-4. Dynamic studies ruled out overmobility. The patient was sent for cardio consultation.

Wide decompressive laminectomy lower 2/3 of L4 and upper half of L5 with foraminotomy left L5 root. Inspection of the disc space revealed extruded disc L4-5. Removal of the extrusion and left sided cleaning L4-5 disc space. Using MultiGen, bipolar motor stimulation of left L5 roots  was achieved with 1.6 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to 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 1.4 Volts. 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 left foot normalized. He was sent to the ward.

The stenosis in this case is a progressive one and surgery will prevent further deterioration of his neurologic status. The agonizing sciatica was due the extruded disc.

This is the 207th 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 at the left L5 root improved dramatically.

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.