The patient came to the clinic 08-April-2017 complaining of weak left foot the last 4 months with numbness both feet and inability to walk more than 100 meters with intermittent claudication for 2 years. MRI lumbar spine performed 23-March-2017 showing severe stenosis L2-3, L3-4 with extruded disc L3-4. Dynamic studies ruled out overmobility. The patient is a known diabetic 20 years with arterial hypertension. The condition of the patient is deteriorating and he is using crutches for 2 months.

On examination, the patient is limping with exaggerated scoliotic stance. SLRS was 85 degrees without pain in both sides. There is drop left foot with weak planterflexion same foot 3/5. There is hypalgesia left L5 root territory.

The patient was sent for cardio evaluation and anticoagulants stopped. ESR was 67 mm/h, CRP 12 mg/L. The patient was advised to take antibiotic before surgery to decrease the incidence of postoperative infection.

Decompressive laminectomy of L3, 4 and lower half of L2 and upper third of L5 was achieved. Foraminotomy of left L3,4 left side was performed. Inspection of L3-4 was performed and decided not to violate it. Using MultiGen, bipolar motor stimulation of the left L4 root was achieved with 5.5 V. The left L5 was achieved with 1.6 V. Waiting 4 minutes the same procedure repeated and bipolar motor stimulation of the left L4 root was achieved with 4.4 V, the left L5 was with 2.0 V. Waiting another 4 minutes the same procedure repeated and bipolar motor stimulation of the left L4 root was achieved with 4.0 V, the left L5 was with 2.0 V.  A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to both left L4 and L5 roots was achieved using 4 bended catheters 10 mm exposed length in 2 stages. Further bipolar motor stimulation of the left L4 root was achieved with 3.7 V, the left L5 was with 1.9 V. Routine closure of the wound.

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

The patient has several problems, which require surgical correction, stenosis at 2 levels and extruded disc L3-4. The recurrence rate is around 7%.

This is the 119th 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 all the involved roots.

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. This trail was performed intentionally to confirm or exclude such this conclusion. Here we noticed that the motor response of the nerves improved after first stimulation, confirming that the improvement came as a result of previous stimulation and BPRF still adding further improvement.

The data of motor stimulation showing that the left L4 root is responsible for drop foot. The repetitive motor stimulation showing incremental improvement of the motor activity starting from 5.5 V down to 3.7 V. This could showing a hint for therapeutic treatment of the drop foot. Time will answer the data.