The patient came to the clinic 11-July-2020 complaining of difficult walking due to weak both lower limbs more the left for 3 years. Rapid deterioration last 10 days with inability to walk more than 10 meters. The patient underwent disc surgery 28 years ago in Germany.

On examination: The patient is limping with exaggerated scoliotic stance. There is an old drop both feet with weak planterflexion both feet -4/5. Abduction left knee and the right quadriceps femoris 4/5. There is analgesia both L5 and S1 territories.

The patient was sent for investigations and MRI dorsal spine, uneventful. There is severe LCS L3-4, L4-5. Dynamic studies ruled out overmobility. Cardio consultation confirmed presence of arterial hypertension and kept Vocado and Norvasc.

Wide decompressive laminectomy L3,4, lower half of L2 and upper half of L5 with foraminotomy both L4 and L5 foraminotomy.  Using MultiGen, bipolar motor stimulation of both L4 and both L5 roots  was achieved with 1.8 Volts for right L4, 2.3 V for right L5, 1.9V for left L4 root, and 0.6V for left L5 root. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to all L4 and L5 roots  was achieved using 4 bended catheters 10 mm exposed length. Further bipolar motor stimulation of both L4 and both L5 roots  was achieved with 1.6 Volts for right L4, 2.0 V for right L5, 1.9V for left L4 root, and 0.6V for left L5 root. 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 both feet improved slightly. She was sent to the ward.

The stenosis in this case is a progressive one and surgery will prevent further deterioration of her neurologic status.

This is the 201st 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 right side and were the same at the left side.

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.