The patient came to the clinic 18-August-2021 complaining of right sciatica after he was operated elsewhere 23-September-2020 for extruded disc L4-5 with huge piece sequestered up in the right side. The drop foot improved, but the sciatica persisted. MRI lumbar spine performed 23-January-2021 showing huge recurrence of L4-5 with right foraminal occlusion with disappearance of the sequester.

On examination, the patient is limping with exaggerated scoliotic stance . SLRS was 80 degrees right side with pain. There is weak dorsiflexion right foot 4/5.

The patient was sent for investigations and MRI performed 18-August-2021 showing further enlargement of the recurrence.

The old wound was used. Neurolysis of the right L4 root. The extruded disc was removed lateral to the axilla and right sided intradiscal cleaning L4-5 was achieved. The extrusion was severely adherent to the dura, that sharp dissection was needed to remove it. Using MultiGen, bipolar motor stimulation of the right L5 root was achieved even with 1.2 Volts, A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the right L5 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the right L5 root was achieved with 1.2 Volts. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. A piece of muscle tissue was used to cover the root territory to minimize the postoperative scar formation and prevent postoperative CSF leak. Routine closure of the wound. Smooth postoperative recovery. The power of the right foot dramatically improved. He was sent to the ward.

MultiGen

Too early now.

There is still an estimated postoperative disc re-recurrence around 7%, since the disc space is not completely shallow.

This is the 223d 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 was the same after BPRF, because it seems it is functioning with normal parameters.

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 at least 5 minute 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.