Neuroendoscopic Transnasal Surgery for Skull Base Tumors: Basic Approaches, Avoidance of Pitfalls, and Recent Innovations

Abstract

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.

Bilateral giant and unilateral duplicated sphenoidal tubercle

“…The endonasal endoscopic surgery provides access to a considerable skull base surface, from the frontal sinus to the foramen magnum and the axis [4,12,13,22]. While performing maxillary antrostomy for the endoscopic approach to the middle cranial fossa, the superomedial part of the pterygopalatine fossa is exposed [14].…”

Role of endoscopic transnasal surgery for skull base chondrosarcoma: a retrospective analysis of 19 cases at a single institution

“…Details of our surgical approach in ETS have been described in previous publications. [55][56][57] Briefly, the surgical navigation system (StealthStation Navigation, Medtronic Japan) and monitoring of CN function (electromyography of extraocular muscles, facial muscles, pharyngeal musculature with the special tracheal tube, and the tongue, as well as auditory brainstem response audiometry) were set to avoid CN injuries (Neuromaster, Nihon Kohden). Endoscopes 4 mm in diameter with 0°, 30°, and 70° lenses were used (175-to 180-mm-long rigid scopes; Karl Storz Endoscopy Japan), which were stabilized in the surgical field with a robotic holding device (Point Setter, Mitaka Kohki).…”

Rhino-Neurochirurgie

“…Die beidhändige ablative intradurale Chirurgie i. e. S. wird jedoch in erster Linie durch den Neurochirurgen vorgenommen [26,29,111,188,228,333,410]. Aufgaben des HNO-Arztes in der zweiten, intrakraniellen Phase werden in der Literatur mit dem Begriff "Navigator", "Assistent", "Endoscopist" oder "Endoscope-Operator" belegt [63,342,413]. Durch eine sachkundige Führung des Endoskopes gewährleistet der "Navigator" den plastischen Eindruck der anatomischen Ziel-und Nachbarstrukturen, die ungetrübte Sicht (mit und ohne gleichzeitige Saugung) bei erhaltenen Freiheitsgraden für die Führung der übrigen Instrumente.…”