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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Case Reports
An endoscopic assisted retrosigmoid approach to the cerebello-pontine angle for resection of an epidermoid cyst.
Epidermoid cysts are rare lesions accounting for 1% of intracranial tumors with approximately 50% located within the cerebello-pontine angle (CPA). Resection is complicated by their close anatomical relation to critical neurovascular structures and their tendency to be densely adherent making complete removal a significant neurosurgical challenge. ⋯ A 30-degree endoscope was used to assist in removal of unseen tumor in Meckel's cave, medial to the lower cranial nerves, and along the ventral pons. The video can be found here: http://youtu.be/bv0lMPbX7BY .
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The posterior skull base and the nasopharynx have historically represented technically difficult regions to approach surgically given their central anatomical locations. Through continued improvements in endoscopic instrumentation and technology, the expanded endonasal approach (EEA) has introduced a new array of surgical options in the management of pathology involving these anatomically complex areas. Similarly, the transoral robotic surgical (TORS) approach was introduced as a minimally invasive surgical option to approach tongue base, nasopharyngeal, parapharyngeal, and laryngeal lesions. ⋯ Given these limitations, several institutions have published feasibility studies with the combined EEA and TORS approaches for a variety of skull base and nasopharyngeal pathologies. In this article, the authors present their clinical experience with the combined endonasal and transoral approach through a case series presentation, and discuss advantages and limitations of this approach for surgical management of the middle and posterior skull base and nasopharynx. In addition, a presentation is included of a unique, simultaneous endonasal and transoral dissection of the nasopharynx through an innovative intraoperative setup.
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Petroclival meningiomas remain a formidable challenge for neurosurgeons because of their location deep within the skull base and proximity to eloquent neurovascular structures. Various skull base approaches have been used in their treatment, and deciding which is the optimal one remains controversial. Attempts at achieving gross- or near-total resections are associated with an increased rate of morbidity and mortality. As adjunctive treatment options such as stereotactic radiosurgery have been developed and become widely available, there has been a trend toward accepting subtotal resections in an effort to minimize neurological morbidity. This paper reviews a recent series of patients with petroclival meningiomas and highlights current management trends and important considerations useful in surgical decision making. ⋯ Achieving gross- or near-total resections of large petroclival meningiomas remains achievable and should be the primary goal of surgical treatment. A retrosigmoid craniotomy remains a workhorse surgical approach for most petroclival tumors of any size. Tumors that are medial to the internal auditory canal and span both middle and posterior cranial fossae are often best treated with a combined transpetrosal approach, which is especially true if there is a preoperative hearing deficit.