The patient was operated by me 29-October-2007. The patient showed dramatic postoperative improvement of the power of the lower limbs and sensation don to both feet except for numbness and hypalgesia of the left S1 root. Check MRI performed 31-October-2007 confirming the presence of residual of the lower part of the tumor. Despite the fact, that the patient showed dramatic improvement, it was decided to reoperate him, as soon as possible, before scar mask the performed surgery 2 days ago.

Reopening of the wound and 20 mm of the dura was dissected down and the lower component of the tumor was brought to the field. Using Inomed ISIS with DNS and EMG of the lower limbs and the sphincter ani both sides, bipolar stimulation was performed over the capsule, where the incision planned to perform. No EMG activity was recorded.
The sac was opened and the tumor material was removed and the previously emptied cavity was dissected, so as to have one cavity.
The upper end of these cavities was connected with tip of the pathological conus medullaris, which showed more or less acceptable neural structure, for what it was decided not to remove the reactionary arachnoidal structures in the fear that they may contain some fibers, responsible for the sacral functions. Water-tight closure of the dura and the wound.

Smooth postoperative recovery, with further improvement of the power of the left foot.
 

It is the third operation for the same level with scars masking the normal anatomy. Without the guidance of the IOM it was impossible to know what exactly the importance of the abnormally localized neural structures.

It was evident that the motor functions of L-2-3-4 and L5 were showing improvement in the records, because of the decompression.
It was sad that the BCR, anal-M-wave, MEP and SEP after pudendal stimulation and the D-wave did not show any signs of the sacral functions before and after the surgery.

Considering that, the surgery was performed in abnormal anatomy, MRI was performed and it showed the presence of another compartment of the tumor, mandating the reoperation to bring the surgery for its maximum morphological and functional result.

From this case and many others, intraoperative real-time MRI combined with IOM guided surgery is a must and we hope to install it in the near future.