Neurosurg Focus
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Case Reports
Endoscopic extended transsphenoidal resection of craniopharyngiomas: nuances of neurosurgical technique.
Endoscopic approaches to the midline ventral skull base have been extensively developed and refined for resection of cranial base tumors over the past several years. As these techniques have improved, both the degree of resection and complication rates have proven comparable to those for transcranial approaches, while visual outcomes may be better via endoscopic endonasal surgery and hospital stays and recovery times are often shorter. Yet for all of the progress made, the steep learning curve associated with these techniques has hampered more widespread implementation and adoption. ⋯ However, recently, endoscopic endonasal resections are more frequently employed for extrasellar and purely third ventricle craniopharyngiomas, whose typical retrochiasmatic location makes them ideal candidates for endoscopic transnasal surgery. The endonasal endoscopic approach offers many advantages, including direct access to the long axis of the tumor, early tumor debulking with minimal manipulation of the optic apparatus, more precise visualization of tumor planes, particularly along the undersurface of the chiasm and the roof of the third ventricle, and a minimal-access corridor that obviates the need for brain retraction. Although much emphasis has been placed on technical tenets of exposure and "how to get there," this article focuses on nuances of tumor resection "when you are there." Three operative videos illustrate our discussion of technical tenets.
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Case Reports
Endoscopic endonasal surgical management of chondrosarcomas with cerebellopontine angle extension.
Skull base chondrosarcomas are slow-growing, locally invasive tumors that arise from the petroclival synchondrosis. These characteristics allow them to erode the clivus and petrous bone and slowly compress the contents of the posterior fossa progressively until the patient becomes symptomatic, typically from cranial neuropathies. Given the site of their genesis, surrounded by the petrous apex and the clival recess, these tumors can project to the middle fossa, cervical area, and posteriorly, toward the cerebellopontine angle (CPA). Expanded endoscopic endonasal approaches are versatile techniques that grant access to the petroclival synchondrosis, the core of these lesions. The ability to access multiple compartments, remove infiltrated bone, and achieve tumor resection without the need for neural retraction makes these techniques particularly appealing in the management of these complex lesions. ⋯ Expanded endoscopic endonasal approaches appear to be safe and effective in the resection of select skull base chondrosarcomas; those with predominant CPA involvement seem particularly amenable to resection through this technique. Further studies with larger cohorts are necessary to test these preliminary impressions and to compare their effectiveness with the results obtained with open approaches.
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The supraorbital eyebrow approach is a minimally invasive technique that offers wide access to the anterior skull base region and parasellar area through asubfrontal corridor. The use of neuroendoscopy allows one to extend the approach further to the pituitary fossa, the anterior third ventricle, the interpeduncular cistern, the anterior and medial temporal lobe, and the middle fossa. The supraorbital approach involves a limited skin incision, with minimal soft-tissue dissection and a small craniotomy, thus carrying relatively low approach-related morbidity. ⋯ The endoscopic supraorbital eyebrow approach is a safe and effective minimally invasive approach to remove extra- and intraaxial anterior skull base, parasellar, and frontal lesions, promoting a rapid recovery and short hospital stay. The location of the eyebrow incision demands a meticulous cosmetic closure, but, with proper technique, cosmetic results are excellent.
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This paper describes a consecutive series of skull base meningiomas resected using an endoscopic endonasal approach through various corridors at a single institution over 7 years. The impact of case selection and experience, the presence of a cortical cuff between the tumor and surrounding vessels, and brain edema on morbidity and rates of gross-total resection (GTR) were examined. ⋯ Surgical outcome for endonasal endoscopic resection of skull base meningiomas depends mostly on careful case selection and surgical experience. Imaging criteria such as the presence of a cortical cuff or brain edema are less important.
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The interpeduncular cistern, including the retrochiasmatic area, is one of the most challenging regions to approach surgically. Various conventional approaches to this region have been described; however, only the endoscopic endonasal approach via the dorsum sellae and the transpetrosal approach provide ideal exposure with a caudal-cranial view. The authors compared these 2 approaches to clarify their limitations and intrinsic advantages for access to the interpeduncular cistern. ⋯ Both approaches are valid surgical options for retrochiasmatic lesions such as craniopharyngiomas. The endoscopic endonasal approach via the dorsum sellae provides a direct and wide exposure of the interpeduncular cistern with negligible neurovascular manipulation. The transpetrosal approach also allows direct access to the interpeduncular cistern without pituitary manipulation; however, the surgical corridor is narrow due to the surrounding neurovascular structures and affords poor contralateral visibility. Conversely, in the presence of large or giant tumors in the interpeduncular cistern, which widen the spaces between neurovascular structures, the transpetrosal approach becomes a superior route, whereas the endoscopic endonasal approach may provide limited freedom of movement in the lateral extension.