A basic model for training of microscopic and endoscopic transsphenoidal pituitary surgery: the Egghead

Background Transsphenoidal endoscopic surgery has gained
popularity in the last 2 decades and is becoming a standard
technique for resection of pituitary adenomas. In contrast to
their ENT colleagues, neurosurgical residents have practically
no endoscopic experience when they reach the training stage
for transsphenoidal procedures.We have developed an affordable
method for repetitive training in endoscopic (and microscopic)
work in a narrow channel, allowing training of the
basic movements needed for resection of pituitary adenoma.
Methods In collaboration with colleagues in the ENT
Department, Cantonal Hospital St. Gall, and the Technical
University of Zurich, a three-dimensional model of the nasal
cavity was developed and patented. The Egghead model consists
of a 3D synthetic reconstruction of the head nasal cavity
and sphenoid sinus. A boiled egg represents the sella. For
validation, 17 neurosurgical residents from the Department
of Neurosurgery, University Hospital of Basel, and
Department of Neurosurgery, Cantonal Hospital of St. Gall,
St. Gall, Switzerland, and two experts performed a standardized
procedure mimicking a transsphenoidal pituitary procedure
by dissecting a corridor to the egg yolk and resecting it,
respecting the surrounding egg white. This procedure was
performed under both microscopic and video-endoscopic visualization.
A score for the precision and speed of the surgical
performance was developed and used.
Results The model allows repetitive training of the resection
of the egg yolk under sparing of the egg white after careful
opening of the shell. The validation data showed a steeper
learning curve using the endoscopic technique than
performing the same task using the microscope. After three
repetitions, the quality of resection was better with the endoscopic
technique.
Conclusions Our model, the Egghead, is affordable, offers
tactile feedback and allows infinite repetitions in basic training
for pituitary surgery. It can be used for training of advanced
neurosurgical residents, who thus far have very few possibilities
of acquiring endoscopic experience.