The patient came to the clinic 29-June-2019 complaining of LBP with left sciatica down to the left foot with numbness all toes left foot after performing fixation of L1 down to S1 05-February-2018 elsewhere.

On examination: She is in agonizing pain, walking with help of 2 persons, for what limping and scoliotic stance were not evaluated. SLRS was 90 degrees right side without pain and 80 degrees in the left with agonizing pain. There was drop both feet and weak planterflexion right foot 4/5. left foot 4/5 with analgesia both feet up to the ankle joints.

The patient was sent for investigations: MRI lumbar spine performed 29-June-2019 ruled out presence of new pathologies above and below the construct. Dynamic studies ruled out overmobility. Lab investigations were uneventful. Ct-scan showed the lower screws penetrating the neural canal both sides inside the sacrum with decompressive laminectomy of L2-3-4. The right L4 root penetrating the intradural space, but the patient is complaining of agonizing left sciatica, for what this finding was ignored. The patient was advised for surgery and start immediately Zinnat 500 twice daily to decrease the possibility of postoperative infection and to be seen by cardiologist.

The lower screws were exposed both sides and using high speed drill the rod was drilled above the nuts. Both screws were removed. Using MultiGen, bipolar motor stimulation of both S1 roots was not achieved even with 5.0 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to both S1 roots inside the holes of the removed screws was achieved using 4 bended catheters 10 mm exposed length. Further bipolar motor stimulation of both S1 roots was not achieved even with 5 V. The patient was put in Reverse Trendelenburg position with Valsalva maneuver. No CSF leak. Routine closure of the wound.

Smooth postoperative recovery. The power planterflexion of both feet improved and the agonizing pain in the left side disappeared. She was sent to the ward.

The overzealous use of pedicle screw fixation has many disadvantages, as in this case. Use it when necessary without causing harm to the patient.

This is the 180th 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 stimulation power of motor stimulation of the severely affected nerves did not improve after BPRF.

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.