The base of the skull has proven to be one of the most challenging anatomic regions to access. In the late 1980s and early 1990s significant breakthroughs were made in accomplishing this goal with much of the work performed here at UPMC. This work involved facial disarticulations and removal of the bones and facial skeletons. This allowed for sequential and layered removal of critical bony, vascular and neural structures until eventually the target deep in the base of the skull and hidden behind the facial elements was reached. The approach was revolutionary as it proved that such surgery was even possible and made previously inoperable tumors now accessible. The field blossomed and grew exponentially in the early part of the decade with much of the world adapting and refining the technique.

In the latter part of the decade it became apparent that the biological cost (morbidity) related to gaining access to this space was very significant. The analogy is that of a sphere and trying to access the center from the perimeter or 'outside in' principle. The layers of tissue that had to be mobilized, removed and then reconstructed were significant. These created significant morbidity to the patients in terms of facial movement, cosmetics, visual function etc.

Concurrent with this realization was the emergence of a new technology, or perhaps more accurately, the incorporation of this technology into neurosurgery. The endoscope had been used extensively in gynecology, laparoscopy (abdominal surgery), thoracic (chest), and cardiac surgery. If you will, the ascension of the endoscope to the 'head' was now occurring. This technique of visualization functions on the principle of a flashlight rather than a cone of light. The microscope starts of as wide base that then focuses light to a narrow point creating a cone of light. This requires a wide exposure to deliver a small area of visualization 'cone of light.' In comparison, the endoscope starts of as a narrow light source that then widens to provide a 'flashlight' view.

In 1999 the skull base program at UPMC made a formal commitment to take advantage of this technology for accessing the skull base. Believing that if we could create a conduit that was narrow through the face we could deliver the flashlight to access the base of the skull and then progressively the brain. The nose provided the ideal conduit. Much work had been done in the ENT field in using the nose to access the region but had stopped short of the skull base. We now extended this to approach and resect tumors of the skull base and then of the brain itself. This approach would allow one to work from 'inside out,' i.e. start directly at the target and work outward. In the process it would not require the layers of facial skeletal removal that were common with conventional approaches. In fact there would be no need for incisions at all as the nose would provide the passage.

It quickly became apparent that in order to reach this lofty goal, equipment and technology would need to be developed that did not previously exist: special instrumentation, drills, image guidance systems etc. In 1999 UPMC created the Center for the Assessment of Surgical Technologies (CAST) that was charged with the task of creating strategic partnerships with industry to undertake biotechnology translational research, i.e., bring technology to the OR that would enable this procedure to occur. Series of relationships were established with industry and UPMC became recognized as a Center of Excellence for the development of this technology.

This has culminated in the evolution of the Expanded Endonasal Approach. Specifically, using this approach we have been able to progressively access the entire skull base with this approach. To date we have undertaken 321 approaches and have been able to extend this to reach central brain tumors and remove them completely through the nostril. It appears that the type of pathology is not a limiting factor nor is the involvement or adhesion to critical nerves and arteries. In fact, this approach allows for a more targeted approach by starting directly at the tumor and working outward. In so doing it minimizes the manipulation and need to move these critical structures of the brain.

In essence the procedure allows both the approach and resection of the tumor to be done with minimal disturbance to the surrounding tissues. We no longer need to make incisions and disassemble the face so we can deliver a "cone of light" (microscope) to the skull base. Instead we can now deliver a 'flashlight' (endoscope/telescope) directly to the target via the nostril. This has the potential to reduce the impact on the patient, lessen the morbidity, and reduce the length of stay in many cases. Som procedures are now performed as overnight stays, with the patient, in some instances, returning to work in days.

As an example, consider the case of 30 year old woman with a tumor in the deep portion of the central skull base presenting twoweeks after delivering a child. The patient would have conventionally undergone a facial disarticulation for access with 12 hours plus of surgery with possibility of swallowing and voice impairment and possible need for a trachestomy. The patient was operated via an Expanded Endonasal approach in approximately six hours and discharged home the next morning. Later that week she was breast feeding at home with no restrictions on activity and no incisions.

Over the past two years we have extrapolated this approach to now reach within the brain, rather than just skull base tumors, to access deep seeded brain tumors using this approach. The results have been very positive. With emerging technologies we believe that in increasing number of tumors will be done through the nose without the need for opening the skull at all via traditional methods. In fact this is already occuring in our practice.