Neuroendoscopic transnasal surgery for skull base tumors: basic approaches, avoidance of pitfalls, and recent innovations.

Since the introduction of endoscopic technology in the neurosurgical field, the role of transnasal surgery has been dramatically enlarged. With this technique, we can approach the anterior cranial base, parasellar region, clivus, cavernous sinus, and craniovertebral junction, less invasively than with conventional microsurgery. This review describes the two major approach methods in endoscopic skull base surgery, the endonasal approach and the transseptal approach. The endonasal approach uses two nostrils without nasal specula and the mucosa on the sphenoid rostrum and the posterior margin of the nasal septum are removed. In the transseptal approach, only a single nostril is available, but using the nasal speculum, sufficient surgical field can be obtained with only a small incision on the septum. In either approach method, it is very important to avoid excessive mucosal damage and to select the appropriate approach for each patient. The endoscopic skull base approach is one of the least invasive surgical procedures, which is a very promising therapeutic choice with potential for further advances. For better surgical outcomes and further progress, cooperation with rhinolaryngologists who have much more knowledge and experience about nasal surgery than neurosurgeons is essential. We believe this article will contribute to the development of safe and effective surgical procedures, and to the benefit of the patients suffering with intractable skull base lesions.