The patient came to the clinic 05-December-2020 complaining of LBP with left sciatica for 20 days. MRI done 03-December-2020 showing spondylolisthesis L3-4, L4-5 with severe stenosis L3-4 and left foraminal occlusion L4-5. The patient is hypertensive for three years in treatment.

On examination: The patient is limping with exaggerated scoliotic stance. There is weak dorsiflexion left foot -3/5. There is hypalgesia left S1 root. There is SLRS left side 20 degrees with pain.

The patient was sent for investigations. Dynamic studies confirmed spondylolisthesis L3-4 and L4-5. CRP was 6.4 mg/L. The patient was sent for cardio consultation. The patient was advised to stop anticoagulants for 10 days before surgery and treat all associated problems.

Skeletonization of the L3, 4, 5 laminae down to the lateral processes. Using Nuvasive Armada surgical technique, transpedicular screw reduction and fixation of L3,4,5 was achieved using 6 screws polyaxial 6.5x45 mm length. The lower left screw was sensitive to motor stimulation below 2 Volts, for what it was inspected the the screw was in contact with root. It was redirected more lateral. Wide decompressive laminectomy L4, lower half of L3 and upper half of L5 with foraminotomy both L4 and L5 roots.  Adjustable cross-connector was applied. 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. 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. All the mobile and displaced segments must be reduced and stabilized.

This is the 205th 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 roots improved dramatically, but the right L4 root still the same.

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.