The patient came to the clinic 03-January-2021 complaining of LBP for more than 1 year with right sciatica for 2 months with difficult walking. MRI lumbar spine performed bad quality 11-November-2020 showing bulge L4-5 and L5-S1 with old wedge fracture D11 and mild spondylolisthesis L5-S1. Dynamic studies showing GII spondylolisthesis L5-S1. The patient is a known diabetic for 15 years in insulin and Glucophage and hypertensive for 20 years. She underwent stinting 3 times 2012.

On examination: The patient is limping with exaggerated scoliotic stance. SLRS was 20 degrees with pain in the right. There is weak dorsi and planterflexion right foot -4/5 with hypalgesia and numbness right S1 territory.

The patient was sent for investigations and MRI lumbar spine performed 13-January-2021, showing the same data as before. The patient was sent for cardio consultation.

Skeletonization f L5 and S1 down to the transverse process of L5. Using CD HORIZON^®LEGACY™5.5 transpedicular fixation of L5-S1 was achieved using 4 polyaxial screws 6.5x40 mm length and cross connector 321. Stimulation of the screws was negative for 5V current. Using MultiGen, bipolar motor stimulation of right S1 root  was not achieved due to scars between the root and the flavum for what BPRF protocol was not performed. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. The harvested bone was milled, put lateral to the rods. Routine closure of the wound.

Smooth postoperative recovery. The power of right foot normalized. She was sent to the ward.

The overmobility will not subside with subsequent pain generation until fusion is carried out.

This is the 208th case using the BPRF mode with MultiGen. This procedure was not performed due to scars between the root and ligamentum flavum. 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 S1 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.