The patient came to the clinic 30-June-2007 complaining of LBP with right sciatica for 1 year with exacerbation the last 5 months.
MRI done 01-April-2007 showed an extruded spondylolisthesis L4-5 I-II degrees.

On examination: the patient had weak dorsiflexion right foot 4/5 with scoliotic stance and SLRS 80 degrees both sides with hypalgesia right L5 territory. The patient was advised to undergo conservative treatment and further studies were planned and performed.

The patient then came 14-November-2007 with deterioration of her status with hypalgesia of both L5 and S1 roots right side. Another MRI was performed 01-December-2007 showing escalation of the spondylolisthesis with isthmolysis.

Laminectomy of L4 was performed and foraminotomy of both L4 and L5 roots was done both sides. All the compressive elements was removed. The right isthmus was fractured. The right L4 root was running perpendicular in relation to the cul de sac. Using ISIS Inomed Highline IOM with pedicular screw scenario, the roots at the start of the operation could be triggered with 0.8-1.4 mA, but later after 20-30 min this was achieved with 4-6 mA. Using image-intensifier the screws were inserted to the L3 and L5 pedicles both sides, during that the EMG recording did not show any sustained activity. Using up to 30 mA the screws did not show any EMG response, confirming that the neural structures are not in contact with the screws. SEP was running in acceptable manner. Inspection of the L4-5 disc showed that it was glistening and it was left without violation. Using bended rods and bridge, fusion was achieved between L3 and L5 bodies. The bone chips harvested from the spinous processii were milled and inserted lateral to the construct.

Routine closure of the wound and smooth postoperative recovery.

The use of the IOM for transpedicular screws is a good practice, but considering that the exposed roots already in the field make this maneuver illogic. This technique has its merits. It could confirm that the far running roots outside the field are not violated and the upper screws also not in contact with roots and no break was having place.

At the end of the operation, the probe could not trigger the roots even with high currents even with 29 mA. This could be a fault of the technology, which start to troubleshoot after 2-3 hours. The operation took place 7 hours. Most of the time trying to know what problem with the ISIS machine. Such an operation take usually 3-4 hours at maximum.