The patient came to the clinic 18-August-2021 complaining of chronic LBP for 8 years with bilateral sciatica. The last 6 months got bilateral sciatica more the left. MRI lumbar spine performed 08-August-2021 showed extruded disc L3-4, L4-5 with spondylolisthesis L3-4 and L4-5 with synovitis both L3-4 facets.

On examination, the patient in agonizing pain, limping with exaggerated scoliotic stance. SLRS 50 degrees right side with pain and 50 degrees left side with more pain. There is weak dorsiflexion right foot 4/5 and -4/5 left foot with no sensory deficit.

The patient was sent for investigations and dynamic studies showed II degree spondylolisthesis L3-4 with horizontal translation of L3-4 and L4-5 and MRI lumbar spine repeated 13-December-2021 showing the same data with severe stenosis both levels and extruded disc L4-5 left side. Lab investigations done showing data needs correction by antibiotics and to be seen by nephrologist and to stop anticoagulants.

Skeletonization of L3,4 lower half of L2 and upper half of L5 until the lateral processes of L3,4 and 5 were seen. Using ERISMA-LP EVOLUTION system, transpedicular screws, polyaxial to L4 and monoaxial to L3 and L5 bodies were inserted 6.5x45 dimensions. Using MultiGen the right screws and upper left L3 pedicle responded brisk at 4.0 Volts. After reduction of the deformity, the left L3 screw slipped out, for what another screw of polyaxial type 6.5X50 mm was inserted to the left pedicle of L2. Check of the construct, showed good reduction of the spine.  Foraminotomy both L3 and L4 roots. Bipolar stimulation of the right L3 root was achieved with 4 Volts. Using bended rods fusion of the area was achieved and the bony material was used lateral to the rods. Using MultiGen, a bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to right L3 root  was achieved using 2 bended catheters 10 mm exposed length. Further bipolar motor stimulation of the right L3 root was achieved with 4 Volts. During decompression, a dural tear took place above the left L5 axilla and double layer stitches with nylon was applied. 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 feet improved. She was sent to the ward.

Too early now.

This is the 301st 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 no 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.