He advised colleagues that there may be limits to what can be achieved with endoscopic dissection of esthesioneuroblastomas and other malignancies, including whether the entire tumor can be removed using endoscopic approaches. Another limit is the individual doctor’s comfort level in dealing with complications, neural injury, and reconstruction.
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October 2008Dr. Snyderman said that duration of surgery might also be a limiting factor, as some of the operations can be lengthy. They certainly can take a toll on the surgeon, he said.
He demonstrated in his talk that one of the main concepts of endoscopic endonasal surgery involves access of the endonasal corridor. This provides you with direct access to tumors, he said. There is no easy way to get there except through the nose. It gets you right to the base of the tumor. The goal is avoiding displacement of neurovascular structures. This becomes no-retraction, no-touch brain surgery.
I think that this is really the only true form of team surgery. You have two disciplines working together simultaneously, and neither one alone can achieve the goals of the surgery. There are lots of benefits from working together. It has been a tremendous advantage.
Endoscopic Techniques
Dr. Snyderman said that when surgeons use an endoscopic approach, there is no difference in dissection goals as compared with conventional surgery. We use both nostrils so that we can operate with both hands. We often start by debulking the tumor and collapsing the tumor onto itself, and that gives us access to the margins of the tumor. We then perform an extracapsular dissection. There is no pulling of tumors. We are not just pulling tumors out through the nose. There is very gentle retraction, he said.
The majority of the time we will use a two-suction dissection technique. One suction provides very gentle retraction. It is not enough traction to tear vessels on the back side of the tumor, and the other suction is a dissector, he explained.
In removal of esthesioneuroblastomas, Dr. Snyderman said, we start by debulking the portion of the tumor that is hanging in the nasal cavity. We identify the landmarks around the margins of the tumor. We find the margins in the front sinus anteriorly, the nasal septum inferiorly, and the orbit laterally.
Then we start removing the bone around the margins of the tumor to expose the dura. The dura is incised at the margins of the skull base, and finally there is complete resection of the dura, the olfactory bulb, and the olfactory tract. There is no retraction of the frontal lobes, but we are still achieving the same resection and we are having excellent visualization. There is nothing blind about this technique.