The patient came to the clinic in ambulance with history of LBP for 20 years with exacerbation last 10 days with left sciatica and numbness of the left foot. He is in agonizing pain. MRI lumbar spine performed 21-January-2021 showing extruded disc L5-S1 with left foraminal occlusion. The patient was asked why he did not perform the surgery at that time. He told me that he was afraid of surgery at that time, but he now urging for that.

On examination, the patient is in agonizing pain, in wheelchair. SLRS was 90 degrees right side without pain and 20 degrees left side with severe pain. There is weak dorsiflexion left foot 3/5 with analgesia left L5 and S1 territories. 

The patient was sent for investigations and MRI done 22-August-2022 showing the same extrusion and bulge L4-5.

Left S1 foraminotomy with left sided removal of the extrusion and left sided cleaning L5-S1 disc space. Using MultiGen, bipolar stimulation of the left S1 root was not responding even to 3.9 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 responding to 3.8 Volts. The patient was put in Reverse Trendelenburg position with Valsalva maneuver and hyperventilation. No CSF leak. Smooth postoperative recovery. The power of the left foot improved. He was sent to the ward.

Too early now.

The recurrence rate here is around 7%, because the disc space is not shallow.

This is the 242d 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. The nerve improved moderately in motor stimulation after performed 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 5 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.