Surgical images of the filum terminale during surgery for the occult tethered cord syndrome. The first image shows a laminotomy performed in the lower lumbar spine on the left side of the patient. (Cephalad is to the left and caudad is to the right.) The dura has been open and retained with two sutures. The most dorsal structure visible is the filum terminale.
The second image shows the filum being elevated with a nerve hook. The tension of the filum is palpable and visible. After testing it with a nerve stimulator to ensure lack of neural activation, the filum will be focally cauterized and sectioned with microscissors and the dural and surgical incisions will be closed.