The patient came to the clinic 26-April-2012 complaining of LBP for 7 years with left sciatica with numbness both feet after performing surgery at KHMC 2008 for spondylolisthesis "L4-5?". The patient did not improve after surgery and she suffered from CSF leak for 4 months after surgery. MRI lumbar spine performed 30-March-2009 showing spondylolisthesis L4-5 II degree with severe stenosis with transpedicular fixation of L3-4. She could walk 100 meters with difficulty. There was weak dorsiflexion both feet -4/5 with hypalgesia left L5 root. The patient was advised to redo surgery, but she escaped. The patient then came 02-January-2017 with further deterioration and difficult walking with help of 2 persons with walker and  bilateral sciatica.

On examination, the patient is walking with help of 2 persons. SLRS was 60 degrees right side with pain. There is weak both feet dorsiflexion 3/5, dorsiflexion, weak planterflexion right foot 4/5 and hypalgesia right L5 territory. There is dripping urine for unknown period of time.

The patient was advised to stop anticoagulants and to be seen by cardiologist. ESR was 38 mm/h and CRP was 24.5 mg/L. She was started in Zinnat 500 twice daily before admission.

Skeletonization of L3,4,5 and upper sacrum until the lateral processes of L5 were identified with exposure of the old construct. It was Medtronic Legacy system with all screws polyaxial version. The right lower screw was loose and extruded backward. The rods were removed and the right lower polyaxial screw was inserted back to get proper alignment with other screws. Using Zodiac system AlphatecSpine system with 2 monoaxial screws 6.5X45 mm were inserted to the L5 body. Motor stimulation was applied to all screws with 8 V and there was no response confirming that the screws are away from the roots.  Two bended rods 100 mm to accept the natural curve of the spine were used. Distraction reduction of L4-5 was added and fusion of L3-4-5 was achieved. Cross-connector was applied. Using MultiGen, bipolar motor stimulation of both L5 roots was achieved extraforaminal with 1.8 V right side and 0.4 V left side. A bipolar pulsed mode RF with 42 Celsius, 240 sec, 2 Hz and 20 msec duration to both L5 roots was achieved using 4 bended catheters 10 mm exposed length. Further motor stimulation done to the right root was 1.5 V and the left was 0.4 V with more brisk responses. The harvested bone was melt and applied lateral to the rods. Routine closure of the wound.

Smooth postoperative recovery. The power of the left foot improved dramatically, but the right foot showing slight deterioration. She was sciatica free. She was sent to the ward.

The patient, the next postoperative day still the same. with decrease of the LBP.

The patient was operated in the wrong level for what she continued to suffer with further deterioration. The right lower screw migrated backward due to overmobility of L4-5 segment.

This is the 106th 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 tell that the electrodes did not migrate during the procedure and the nerve is functioning properly. Here there was considerable improvement of the threshold of stimulation power of motor stimulation after the BPRF in the right side but the left root showed good response before and after application. It seems that the right L5 root suffered from longstanding trauma.

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 anaesthesia protocol also the same.

The electrodes were applied in this case extraforaminal without performing foraminotomy.

In the next case, it is better to apply motor response to the roots of interest to see if there is deterioration of motor conductivity after applying distraction. In such case it is better to decrease the magnitude of distraction to avoid deterioration of the root function.