December 10, 2014
Let's discuss nuances of technique for a section of thoracic spinal cord hemangioblastomas. This is a 42 year-old male who presented with progressive paraparesis. MRI evaluation demonstrated a subtle finding in actually a lower part of the thoracic spinal cord. There is potentially some edema associated with this subtle lesion. The actual images, again, reveal the mass to be slightly posteriorly located within the substance of the spinal cord. Due to progressive worsening of his paraparesis, the patient underwent thoracic laminectomies and midline durotomy was completed, and the affected surface of the spinal cord was exposed. So much sensory evoked potentials and motor evoked potentials were monitored during the procedure. A dental tool is used along with a blade to cut the dura efficiently. The edges of the dura are attacked away from the spinal cord. The nodule is readily apparent on the posterolateral surface of the cord. All the arachnoid bands are generously dissected so that their feeding arteries and draining veins can be differentiated. Obviously nerve roots are protected. Here is caudal, here is cranial. I'm inspecting the more lateral margin of the nodule. Some feeding vessels lead to the nodule, just along the nerve root. Obviously I like to preserve as much of their neural tissue as possible. Therefore, coagulation of the nodule continues right at the margin of their mass. After the surface of the nodule is devascularized, a planar dissection is developed between the hemangioblastoma and the spinal cord. These lesions are primarily epi-pial. Therefore, the substance of this spinal cord should not be entered doing removal of these lesions. You can see, I stay very close to the surface of the nodule, coagulate right on the surface, preserving as much of the spinal cord and the pia as possible. I may enter the nodule at certain locations, however, focal coagulation often leads to adequate hemostasis. Any of the normal veins on the surface of the cord are protected. Here's a feeding vessel to the nodule along the superior portal of the capsule. Continue sharp dissection, and you can see the peeled surface is relatively intact. I continue to deliver the deeper part of the nodule. Using gentle blunt dissection, aggressive coagulation is obviously avoided. Nodule is now mobilized and rotated out of its cavity. Try to avoid the use of the bipolar forceps and coagulation as much as possible. A gliotic surface at the border of the lesion is apparent. I continue to work around the circumference of the nodule. Most of the nodule is now disconnected. You can see the resection cavity, preservation of most of the surrounding peeled membranes. Obviously the surrounding areas are inspected to assure gross total removal of the mass. I don't see any other abnormality anterior to the nerve roots. All the normal veins within the posterior surface of the spinal cord are functional. The mission has been accomplished. Dural closure is conducted primarily and in a watertight fashion. This basic technique is also illustrated here. There was no change in our somatosensory or motor evoked potentials during excision of this mass, and this patient recovered from his surgery without any new deficits, and in his three-months evaluation demonstrated significant improvement in his preoperative neurological deficits. Thank you.
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