The patient came to the clinic 06-July-2021 complaining of LBP with left sciatica for 4 months with numbness of the left L5 territory.

On examination, the patient is limping with exaggerated scoliotic stance . SLRS was 45 degrees left side with pain. There is weak dorsiflexion left foot 4/5 with hypalgesia left L5 territory.

The patient was sent for investigation and MRI of the lumbar spine done 06-July-2021 showed extruded disc L4-5 with left foraminal occlusion and 3D MR Myelography showed cystic lesion above the extrusion compressing the dural sac.

The C-arm was used to verify the L4-5 level. Left L4-5 hemiflavotomy with extended foraminotomy left L5 root. The extruded disc was removed lateral to the axilla and left sided intradiscal cleaning L4-5 was achieved.  The left side of the lamina was drilled off superiorly to identify the cystic lesion, which was actually an arachnoid cyst behind the L5 root and extending up from the posterior-left side 15 mm above the axilla. Step-wise coagulation to shrink the arachnoid, which at the end disappeared and the real L5 root appeared. Using MultiGen, bipolar motor stimulation of the left L5 root was achieved even with 1.9 Volts, A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to the left L4 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the left L5 root was achieved with 1.6 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 left foot dramatically improved. He was sent to the ward.

MultiGen

The patient was diagnosed, admitted and to be followed by Dr. Ali Al-Bayyati.

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

This is the 218th 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 nerves did not change dramatically 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.

This rare case with extradural arachnoid cyst with extruded disc simultaneously compressing the running by root.