The patient came to the clinic 13-November-2021 with flail left foot with back-slap applied to her left foot after performed surgery for PLD L5-S1 2 weeks ago elsewhere. The condition deteriorated immediately after surgery. The patient underwent surgery 11 years ago for PLD L5-S1 left side and MRI done before the last surgery showing medium size extrusion L5-S1 with extradural compression left side. MRI done 10-November-2021 after surgery showing the extrusion penetrating the dura and intradurally compressing the roots. Dynamic studies ruled out overmobility. She is a known hypertensive for 9 years in treatment.

On examination: she is in agonizing pain, limping dragging her left leg with a cast applied to her left foot. To examine her the cast was removed and the stitches of the lastly performed surgery, were also removed. SLRS was 80 degrees both sides with pain in the left. There is weak planterflexion left foot 2/5, dorsiflexion of the left foot 3/5 and the big toe 1/5.

The patient was sent for lab investigations and ESR was 37 mm/h, for what Zinnat was started twice a day before surgery.

The level of L5-S1 was identified by the C-arm. Extended foraminotomy left S1 root with removal of compressing elements. The extruded disc was removed in several tiny pieces to avoid sudden onset CSF leak, After that the disc disc of L5-S1 was cleaned from the left side. Using Omnipaque 10 cc, myelography was used to rule out presence of intradural piece. By the the C-arm the data were negative. Intraoperative MRI was not achievable due to technical problem with the docking system of the Skyra. Using MultiGen, bipolar stimulation of the left S1 root was achieved with 2.8 Volts. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the left S1 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar stimulation of the left S1 root was achieved with 2.0 Volts. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. A fat tissue with pedicle was used to cover the dura to minimize the postoperative scar formation and prevent postoperative CSF leak. Routine closure of the wound. Smooth postoperative recovery. The power of the left foot improved slightly. She was sent to the ward.

Too early now.

This is the 230th 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 affected nerve showed noticeable improvement 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.