====== Endoscopic Endonasal Approach Indications ====== A PubMed search for articles published between January 1990 and January 2014 about "endoscopic skull base surgery", "endoscopic transsphenoidal approach", "endoscopic treatment of parasellar tumors" and "suprasellar lesions" was performed. According to the current data, [[endoscopic surgery]] seems to be superior to open and [[transsphenoidal surgery]] microscopic removal of [[giant pituitary neuroendocrine tumor]]s. Endoscopy is at least as successful as [[transsphenoidal microsurgery]] for the removal of [[pituitary neuroendocrine tumor]]s and [[craniopharyngioma]]s. Transcranial open approaches, in the context of anterior midline [[skull base meningioma]]s, present higher rates of gross total resection, fewer complications and better clinical results than endoscopy approaches. The rate of postoperative Cerebrospinal fluid fistula has been significantly reduced with the introduction of new techniques such as the Hadad- Bassagasteguy flap but still represent one of the most important complications of this technique. Currently, selected tumors located at the anterior, middle and posterior fossa can be adequately assessed using the endoscope with low rates of postoperative Cerebrospinal fluid fistulas. Endoscopic surgery has substantially evolved in the last decades through the collaboration of different teams around the world. The endoscope is now an essential tool in the neurosurgery armamentarium with great potential for new applications in the nearby future ((Almeida JP, De Albuquerque LA, Dal Fabbro M, Sampaio M, Medina R, Chacon M, Gondim J. Endoscopic skull base surgery: evaluation of current clinical outcomes. J Neurosurg Sci. 2015 Nov 23. [Epub ahead of print] PubMed PMID: 26603533. )). ---- The evolution of the endoscopic endonasal [[transsphenoidal approach]], which was initially reserved only for [[sellar lesion]]s through the [[sphenoidal sinus]] cavity, has lead in the last decades to a progressive possibility to access the [[skull base]] from the [[nose]]. This route allows midline access and visibility to the suprasellar, retrosellar and parasellar space while obviating brain retraction, and makes possible to treat transsphenoidally a variety of relatively small midline skull base and parasellar lesions traditionally approached transcranially. In a cadaveric model, the piezoelectric endoscopic transsphenoidal craniotomy (PETC) is technically feasible. This technique allows the surgeon to create a bone flap in endoscopic transnasal approaches similar to existing standard transcranial craniotomies. Future trials will focus on skull base reconstruction using this bone flap ((Tomazic PV, Gellner V, Koele W, Hammer GP, Braun EM, Gerstenberger C, Clarici G, Holl E, Braun H, Stammberger H, Mokry M. Feasibility of piezoelectric endoscopic transsphenoidal craniotomy: a cadaveric study. Biomed Res Int. 2014;2014:341876. doi: 10.1155/2014/341876. Epub 2014 Feb 9. PubMed PMID: 24689037.)). Preserving normal sinonasal physiology by limiting middle turbinate resections, avoiding unnecessary maxillary antrostomies, and reducing the use of nasoseptal flaps when feasible results in less sinonasal morbidity and more rapid recovery during the postoperative period ((Thompson CF, Suh JD, Liu Y, Bergsneider M, Wang MB. Modifications to the endoscopic approach for anterior skull base lesions improve postoperative sinonasal symptoms. J Neurol Surg B Skull Base. 2014 Feb;75(1):65-72. doi:10.1055/s-0033-1356492. Epub 2013 Oct 10. PubMed PMID: 24498592.)). ==== Pituitary surgery ==== see [[Endoscopic endonasal approach for pituitary neuroendocrine tumor]]. ==== Cerebral Aneurysm ==== see [[Endoscopic endonasal approach for intracranial aneurysm]] ==== Optic neuropathy ==== Based on the anatomic relationship between sinonasal complex and [[orbit]], this approach could be a smart solution for approaching the medial [[orbital region]]. These techniques should be considered a valid option for [[optic nerve decompression]] in cases of Graves ophthalmopathy and post-traumatic optic neuropathy as well as for addressing extraconal or intraconal lesions placed medially to the optic nerve course ((Castelnuovo P, Turri-Zanoni M, Battaglia P, Locatelli D, Dallan I. Endoscopic Endonasal Management of Orbital Pathologies. Neurosurg Clin N Am. 2015 Jul;26(3):463-72. doi: 10.1016/j.nec.2015.03.001. Epub 2015 May 7. Review. PubMed PMID: 26141364. )). Four main pathologies with outcomes after treatment were identified for discussion: [[pituitary neuroendocrine tumor]]s, [[craniopharyngioma]]s, [[anterior skull base meningioma]]s, and [[chordoma]]s. Within all four of these tumor types, articles have demonstrated the efficacy, and in certain cases, the advantages over more traditional microscope-based techniques, of the endonasal endoscopic technique ((Lobo B, Heng A, Barkhoudarian G, Griffiths CF, Kelly DF. The expanding role of the endonasal endoscopic approach in pituitary and skull base surgery: A 2014 perspective. Surg Neurol Int. 2015 May 20;6:82. doi: 10.4103/2152-7806.157442. eCollection 2015. Review. PubMed PMID: 26015870; PubMed Central PMCID: PMC4443401. )). The endoscopic endonasal approach is a safe and effective procedure for the management of recurrent and/or regrowing pituitary tumors previously treated by either a microsurgical or an endoscopic approach ((Cavallo LM, Solari D, Tasiou A, Esposito F, de Angelis M, D'Enza AI, Cappabianca P. Endoscopic endonasal transsphenoidal removal of recurrent and regrowing pituitary neuroendocrine tumors: experience on a 59-patient series. World Neurosurg. 2013 Sep-Oct;80(3-4):342-50. doi: 10.1016/j.wneu.2012.10.008. Epub 2012 Oct 6. PubMed PMID: 23046913. )). ==== Craniopharyngiomas ==== see [[Craniopharyngioma endoscopic endonasal approach]] ==== Anterior skull base meningiomas ==== Is feasible and safe for the complete resection of [[anterior skull base meningioma]]s with intra- and extracranial extension in one stage in selected cases. Although the endonasal endoscopic approach has been applied to remove [[olfactory groove meningioma]]s, controversy exists regarding the efficacy and safety of this approach compared with more traditional transcranial approaches [[Cavernous sinus lesion]]. ==== Petrous apex Choleterol granulomas ==== The EEA is a safe and effective alternative to traditional open approaches to petrous apex CGs ((Paluzzi A, Gardner P, Fernandez-Miranda JC, Pinheiro-Neto CD, Scopel TF, Koutourousiou M, Snyderman CH. Endoscopic endonasal approach to cholesterol granulomas of the petrous apex: a series of 17 patients: clinical article. J Neurosurg. 2012 Apr;116(4):792-8. doi: 10.3171/2011.11.JNS111077. Epub 2012 Jan 6. PubMed PMID: 22224788.)). ==== Cerebrospinal fluid fistula ==== [[Endoscopic endonasal approach for Cerebrospinal fluid fistula]] ==== Access to the intraorbital optic nerve segment ==== see [[transorbital approach]]. ==== Nonvestibular schwannomas ==== Nonvestibular schwannomas of the skull base often represent a challenge owing to their anatomic location. With improved techniques in endoscopic endonasal skull base surgery, resection of various ventral skull base tumors, including schwannomas, has become possible. To assess the outcomes of using endoscopic endonasal approach (EEA) for nonvestibular schwannomas of the skull base. Seventeen patients operated on for skull base schwannomas by EEA at the University of Pittsburgh Medical Center from 2003 to 2009 were reviewed. Three patients underwent combined approaches with retromastoid craniectomy (n = 2) and orbitopterional craniotomy (n = 1). Three patients underwent multistage EEA. The rest received a single EEA operation. Data on degree of resection were found for 15 patients. Gross total resection (n = 9) and near-total (>90%) resection (n = 3) were achieved in 12 patients (80%). There were no tumor recurrences or postoperative Cerebrospinal fluid fistulas. In 3 of 7 patients with preoperative sensory deficits of trigeminal nerve distribution, there were partial improvements. Patients with preoperative reduced vision (n = 1) and cranial nerve VI or III palsies (n = 3) also showed improvement. Five patients had new postoperative trigeminal nerve deficits: 2 had sensory deficits only, 1 had motor deficit only, and 2 had both motor and sensory deficits. Three of these patients had partial improvement, but 3 developed corneal neurotrophic keratopathy. An EEA provides adequate access for nonvestibular schwannomas invading the skull base, allowing a high degree of resection with a low rate of complications ((Shin SS, Gardner PA, Stefko ST, Madhok R, Fernandez-Miranda JC, Snyderman CH. Endoscopic endonasal approach for nonvestibular schwannomas. Neurosurgery. 2011 Nov;69(5):1046-57; discussion 1057. doi: 10.1227/NEU.0b013e3182287bb9. PubMed PMID: 21673609.)).