Acta Neurochirurgica

, Volume 157, Issue 10, pp 1771–1777 | Cite as

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

  • Doortje C. Engel
  • Andrea Ferrari
  • Abel-Jan Tasman
  • Raphael Schmid
  • Ralf Schindel
  • Sarah R. Haile
  • Luigi Mariani
  • Jean-Yves Fournier
Experimental research - Neurosurgery Training



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.


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.


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.


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.


Neurosurgery training Training model Pituitary surgery Endoscopy Microscopy 



This project was funded by the Clinical Trials Unit Commission of the Canton of St. Gall, Switzerland. The authors thank Karl Storz® for providing the endoscopic setup. The authors also thank Prof. Rachel Rosenthal, Department of Surgery, Basel University, for input on training models in surgery and Karin Inauen, BSc, for assistance during the experiments.

Conflict of interest

The authors declare that they have no conflict of interest. The services of Inspire AG (Schindel and Schmidt) for cooperation with development and production were reimbursed at regular rates.


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Copyright information

© Springer-Verlag Wien 2015

Authors and Affiliations

  • Doortje C. Engel
    • 1
    • 6
  • Andrea Ferrari
    • 2
  • Abel-Jan Tasman
    • 3
  • Raphael Schmid
    • 4
  • Ralf Schindel
    • 4
  • Sarah R. Haile
    • 5
  • Luigi Mariani
    • 2
  • Jean-Yves Fournier
    • 1
  1. 1.Department of NeurosurgeryCantonal Hospital of St. GallSt. GallSwitzerland
  2. 2.Department of NeurosurgeryUniversity Hospital of BaselBaselSwitzerland
  3. 3.Department of ENTCantonal Hospital of St. GallSt. GallSwitzerland
  4. 4.Inspire® - ETH ZurichSt. GallSwitzerland
  5. 5.Clinical Trials UnitCantonal Hospital of St. GallSt. GallSwitzerland
  6. 6.Department of NeurosurgeryUniversity Hospital TuebingenTuebingenGermany

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