PREOPERATIVE DIAGNOSES:
1. Intractable seizure disorder.
2. Status post right frontotemporal parietal craniotomy and placement of
subdural recording grids for intracranial stimulation and monitoring.
3. Right frontocortical migrational abnormality and presumptive cause for
seizure disorder.
POSTOPERATIVE DIAGNOSES:
1. Intractable seizure disorder.
2. Status post right frontotemporal parietal craniotomy and placement of
subdural recording grids for intracranial stimulation and monitoring.
3. Right frontocortical migrational abnormality and presumptive cause for
seizure disorder.
PROCEDURE PERFORMED:
1. Right frontotemporal parietal craniotomy (image guided); resection of the
epileptogenic cortex involving the frontal lobe and area of cortical dysplasia
with intraoperative monitoring.
2. Removal of subdural cortical recording grids.
3. Use of the operating microscope in microdissection.
SURGEON:
Michael Edwards, M.D.
ASSISTANTS:
Robert Dodd, M.D. and Donald Olson, M.D.
ANESTHESIA:
General endotracheal anesthesia.
ANESTHESIOLOGIST:
Pediatric Anesthesia.
ESTIMATED BLOOD LOSS:
BLOOD TRANSFUSIONS:
50 cc.
None.
DESCRIPTION OF PROCEDURE: Xxxxx was brought from the monitoring area to the
operating room table. Endotracheal anesthesia was established. Appropriate
lines and monitors were placed, including arterial lines, Foley catheter and
appropriate IVs. She was continued on antibiotic prophylaxis with the third
generation cephalosporin. Dexamethasone 10 mg was given. After she was
carefully padded and all bony prominences were carefully protected, a warming
blanket was placed over the child. A roll was placed beneath the right
shoulder. The hair was shaved surrounding the prior craniotomy. The wires
exiting her scalp in the right posterior parietooccipital region were prepped
out with Betadine. We shave the remaining hair at the request of her mother.
We then shaved closely around the craniotomy site excluding the wires that
were externalized from the scalp. The wires were covered with a Betadine
soaked sponge. We then draped around the entire operative area excluding the
exit sites for the wires using Steri-Drapes. The Mayfield-Keyes skeletal
fixation was used for localization of the child and stability. Internal
fiducial holes were then placed in the surrounding craniotomy.
The skin was scrubbed for 10 minutes with Betadine scrub and painted with
alcohol and DuraPrep. Sterile towels and Ioban drapes and sterile sheets were
applied. The prior right frontotemporal parietal craniotomy was opened with a
15 blade. The superficial deep sutures were removed. The scalp flap was
elevated off the prior bone flap and a roll of sponge was placed beneath the
skin surface. More sponges were placed over the galeal surface and the flap
was retracted with scalp hooks.
The wires exiting from beneath the bone flap were cut and, with the assistance
of Anesthesia, the wires that had been externalized below the drapes were then
removed from beneath the drapes.
The sutures holding the bone flap in position were cut. The bone flap was
elevated, washed and preserved in antibiotic solution. Hemostasis was
established on the dura with a bipolar cautery.
We next removed the sutures holding the dura in position over the subdural
grid. The dura was retracted with fine silk sutures and covered with moist
Telfa.
Using a combination of image guidance along with the mapping of the grid,
which was overlaid on a photograph of the brain, Dr. Olson and I determined
the site of abnormal cortical activity and the area in which there was normal
function. The normal function sat in a gyrus well behind the area of cortical
irritability. The abnormality sat mostly anterior to the cleft of the brain,
which represented the area of cortical dysplasia.
Therefore, we decided to resect the gyrus both posterior and anterior to the
cortical dimple or cleft. We were to extend our dissection slightly
anteriorly to the gyrus beneath the edge of the dura, in essence one gyrus
more anterior than our exposure, but this could be reached by elevation of the
dura anteriorly.
The grid was carefully removed and using the irrigating bipolar and loop
magnification. We carefully coagulated the pial surface to define the
surrounding resection site. Through the rather generous cortical resection
which involved approximately a gyrus behind as well as two gyri anterior to
the cleft and extending well inferior and superior to the cleft.
We covered the area of cortex in which there was found to be normal function
and the entire site was kept moist with warm Physiosol throughout the
procedure.
Using the operating microscope, we began coagulating the pia in a
circumferential fashion and incising the pia with a #11 blade and
microscissors. We sequentially sacrificed the pial vessels and small cortical
vessels in the surrounding gyrus posteriorly and well anteriorly to the cleft.
Using the fenestrated suction and irrigating bipolar cautery, we dissected
through the cortex to the gray-white junction and identified the underlying
white matter. We worked circumferentially around the area of gluteal
migration or abnormality. We maintained our plane between normal tissue and
the abnormal epileptogenic cortex by application of brain cotton or Cottonoid
paddies. After circumferentially extending through the gray matter in a
360-degree arc around the lesion, we dissected down to the white matter and
began elevating the epileptogenic cortex, finding a plane in the white matter
and eventually identifying the migrational abnormality, which extended
slightly deeper into the white matter.
In this area we extended our
dissection beneath the cortical cleft or dimple and excised the entire
surrounding area surrounding the dimple as determined by the preoperative
electrocorticography and the intraoperative photography and image guidance.
The entire operative site was packed with Cottonoid paddies. We then extended
our dissection anteriorly one gyrus forward into the frontal lobe by using a
similar technique of coagulating the pial vessels, incising them with
microscissors and performing in essence a subpial dissection of the gyrus
extending anteriorly beneath the edge of the anterior bone flap.
The entire specimen was submitted to Pathology. Some of the edge of the
resected tissue was submitted for laboratory diagnostic studies.
In conjunction with Pathology we marked the area of anterior and posterior
resection sites. The entire specimen was submitted to Pathology in as much in
anatomic fashion as possible.
Meticulous hemostasis was established on the resection site with the bipolar
cautery. We then irrigated copiously with warm saline. Multiple Valsalva
maneuvers were performed. No bleeding was noted from the operative area.
The resection site was covered with large pieces of Surgicel. The dura was
brought back into position and packed into position with interrupted 4-0
Nurolon and the majority closed with running 4-0 Vicryl. However, there was a
defect posteriorly which required a small EnDura dural substitute graft. This
was placed in position and closed with running 4-0 Vicryl suture. A
watertight dural closure was carried out.
We then irrigated the entire site with bacitracin solution, obtained
hemostasis in the dura and surrounding tissues with a bipolar cautery and
placed FloSeal in the epidural space surrounding the bone flap.
The entire dural closure was covered with a large piece of DuraGen. The bone
flap was repositioned and anchored in place with two bur hole covers and a
rectangular plate using 4-mm screws. Rigid fixation was carried out with the
bone flap to prevent the risk of moving should the child have a seizure and
fall.
We again irrigated the operative site with antibiotic solution. We closed the
galea with inverted interrupted 3-0 Vicryl suture, the skin with running 4-0
Monocryl. Xeroform gauze and Telfa was applied. Drapes were removed. We
again prepped the exit site for the recording wires with Betadine. We used
staples the close the exit sites in the scalp and then similarly dressed this
area with Xeroform gauze, Telfa and Tegaderm.
Xxxxx was taken out of the head holder. She was awoken, extubated and
returned to pediatric intensive care unit in stable condition. Xxxxx
tolerated the procedure well. There were no intraoperative complications.
Needle, sponge, and cottonoid counts were correct.
The specimen to Pathology consistent of an epileptogenic cortex with area of
cortical migrational abnormality.