The patient came to the clinic 13-September-2020 complaining of difficult walking due to weak left lower limb after falling down 30-August-2020. He had similar episode 3 years ago. MRI lumbar spine performed 03-October-2017 showing LCS L4-5. EMG done 10-March-2017 showing peripheral sensory neuropathy of lower extremities. The patient had attacks of TIA with aphasia several times during the last year. The patient is a known diabetic with arterial hypertension for 10 years. He is receiving Omnic for hypertrophic prostate for three years.

On examination: The patient is using crutches, limping with no scoliotic stance. There is weak dorsi and planterflexion left foot 4/5.

The patient was sent for investigations and MRI lumbar spine, showing severe LCS L4-5 and less at L3-4. Dynamic studies ruled out overmobility. The patient was sent for cardio and GI specialist for melena. The patient was advised to stop anticoagulants for 10 days before surgery and improve the kidney function parameters by drinking more amount of water. The patient was admitted 1 day before surgery to follow up his diabetes mellitus and receive 2 units packed cells and FFP because his Hb was 9.7 mg/dL

Wide decompressive laminectomy L4, lower half of L3 and upper half of L5 with foraminotomy left L4 and L5 roots.  Using MultiGen, bipolar motor stimulation of left L4 with 2.1 Volt and left L5 roots  was achieved with 1.9 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to left L4 and L5 roots  was achieved using 4 bended catheters 10 mm exposed length. Further bipolar motor stimulation of left L4  with 2.0 Volts and left L5 root  was achieved with 1.1 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.

This is the 202d 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.