The expanding role of the endonasal endoscopic approach in pituitary and skull base surgery: A 2014 perspective

Abstract

Background: The past two decades have been the setting for remarkable advancement in endonasal endoscopic neurosurgery. Refinements in camera definition, surgical instrumentation, navigation, and surgical technique, including the dual surgeon team, have facilitated purely endonasal endoscopic approaches to the majority of the midline skull base that were previously difficult to access through the transsphenoidal microscopic approach.

Methods: This review article looks at many of the articles from 2011 to 2014 citing endonasal endoscopic surgery with regard to approaches and reconstructive techniques, pathologies treated and outcomes, and new technologies under consideration.

Results: Refinements in approach and closure techniques have reduced the risk of cerebrospinal fluid leak and infection. This has allowed surgeons to more aggressively treat a variety of pathologies. Four main pathologies with outcomes after treatment were identified for discussion: pituitary adenomas, craniopharyngiomas, anterior skull base meningiomas, and chordomas. 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.

Conclusions: The endonasal endoscopic approach is a necessary tool in the modern skull base surgeon's armamentarium. Its efficacy for treatment of a wide variety of skull base pathologies has been repeatedly demonstrated. In the experienced surgeon's hands, this technique may offer the advantage of greater tumor removal with reduced overall complications over traditional craniotomies for select tumor pathologies centered near the midline skull base.

Keywords: Craniopharyngioma; chordoma; endoscopic endonasal surgery; endoscopic pituitary surgery; endoscopic skull base surgery; tuberculum sella meningioma.

Figure 1

A 71-year-old female who developed progressive vision loss in the left eye over 6 months. Because of her worsening vision she underwent a brain MRI with gadolinium (a and b) revealing a 24 × 19 × 16 mm sellar mass with suprasellar extension. The chiasm was markedly compressed (white arrowheads). The normal gland was thinned and pushed superiorly toward the right. Formal neuro-ophthalmologic visual field testing confirmed severe global decreased acuity in the left eye, and a superior temporal quadrant defect in the right eye. Her preoperative prolactin level was 41.5 ng/ml indicating the tumor was not a prolactinoma. The patient underwent endonasal endoscopic tumor removal. The patient's immediate postoperative MRI (c and d) and 1 year postoperative MRI (e and f) revealed a GTR of the tumor and decompression of the optic apparatus (white arrows)

Figure 2

A 52-year-old male who presented with worsening bouts of cold intolerance, 18 kg weight gain over 2 years, fatigue, decreased libido, polyuria, and 6 months of worsening vision. Endocrinological workup revealed central hypothyroidism, hypogonadotropic hypotestosteronism. T1 MRI with gadolinium (a and b) demonstrated a heterogeneously enhancing cystic suprasellar retrochiasmatic mass. The patient underwent an endonasal endoscopic transsellar, transplanum resection of the tumor. The pathology was consistent with craniopharyngioma. The postoperative MRI with gadolinium 1 day after surgery (c) demonstrated near total removal of the tumor with a small amount of tumor purposefully left along the posterior edge of the optic chiasm given its dense adhesions to the optic apparatus (white arrow). MRI with gadolinium 6 months after surgery (d and e) reveals residual tumor along the chiasm that was followed with serial MRIs

Figure 3

A 65-year-old female with gradual visual deterioration. The preoperative T1 MRI with gadolinium (a and b) demonstrated an extra-axial mass arising from the tuberculum sella dura with dural tail (white arrow). The patient underwent an endonasal endoscopic transplanum, transsellar skull base approach for resection of the mass. Pathology was consistent with a benign meningioma. Intraoperative views (c,d,e,f) of tumor (t) removal with separation away from the optic nerves (o), chiasm (ch), anterior cerebral artery (aca), and infundibulum (i). The immediate postoperative T1 MRI with fat suppression and gadolinium (g) demonstrated a GTR of the tumor. The 3-month postoperative T1 MRI without gadolinium (h and j) and with gadolinium (i and k) demonstrate fat graft in the resection cavity without evidence of tumor recurrence

Figure 4

A 61-year-old female who presented with headaches. Her MRI with gadolinium (a and b) revealed a sphenoclival mass with preservation of sellar contents (white arrow) and intradural invasion and compression of the brain stem (white arrowheads). The patient underwent a transsphenoidal, transclival EEA for resection of the tumor. The pathology was consistent with chordoma. A postoperative CT (c) was completed immediately after surgery to assure no dislodgment of her multilayered skull base reconstruction with intradural fat graft (*), bone (black arrow), extradural fat graft (**), and right nasoseptal flap, which were buttressed with Merocel packs (***). Fat suppression T1 MRI with gadolinium was completed on postoperative day 1 (d) with clear enhancement of the nasoseptal flap (black arrowheads). Her fat suppression MRI with gadolinium 3 months after surgery (e and f) demonstrate no definitive tumor enhancement. The enhancement along the right posterior and superior nasal cavity (#) is consistent with the right nasoseptal flap enhancement