Alaa S. Montaser

The Role of Endoscopy in Resection of Intracanalicular Vestibular Schwannoma via Middle Fossa Approach: Technical Nuances

BACKGROUNDnSurgical resection of vestibular schwannomas (VS) located within the internal auditory canal (IAC) is challenging, especially those located very laterally in the IAC. Various transcranial approaches have been described for resection of intracanalicular VS including retrosigmoid, translabyrinthine, and middle fossa approaches. Each approach has its indications, advantages, and limitations. The middle fossa approach (MFA) is considered by many authors as the gold standard approach for resection of small intracanalicular VS in young patients with serviceable hearing; however, there is often a limitation in complete visualization of the tumor.nnnMETHODSnThe authors present an illustrative case to highlight the technical nuances of complementary use of endoscopy in MFA for complete resection of intracanalicular VS located at the IAC fundus, preserving preoperative hearing status and mainting intact facial nerve function.nnnRESULTSnIn our experience, the combined use of the endoscope and the microspe as described here and illustrated in our case, improves visualization of the IAC and its contents, improving ressection and outcomes.nnnCONCLUSIONSnMFA allows for a direct yet safe surgical corridor to small intracanalicular VS. The implementation of endoscopy with MFA, especially for VS located laterally in the IAC, allows for better opportunity for complete resection of the tumor with improved preservation of hearing and facial nerve function.

Predictors of Postoperative Diabetes Insipidus Following Endoscopic Resection of Pituitary Adenomas

Abstract Context The development of diabetes insipidus (DI) following transsphenoidal resection of pituitary adenomas has been associated with higher postsurgical morbidity and longer hospitalizations. Identifying these patients promptly and efficiently can lead to improved health care outcomes. Objective We evaluated our institution’s incidence of DI following pituitary adenoma resection and assessed for preoperative risk factors that were associated with postoperative DI. Design A retrospective review of 271 patients who underwent endoscopic endonasal resection of a pituitary adenoma between July 2010 and December 2016 by a single neurosurgical provider was completed. Setting All cases were from a single-center, academic institution. Patients Patients with a pituitary adenoma diagnosis confirmed on histology were included in the study. Those with previous surgery by a different provider were excluded. Results The incidence of DI at our institution was 16.6% (45 of 271 patients), with only 4% (11 patients) having permanent DI. The presence of visual abnormalities (CI 1.29 to 4.75), suprasellar extension (CI 1.36 to 6.88), and maximal tumor diameter (1.02 to 1.08) was significantly associated with an increased incidence of postoperative DI (P < 0.05). Hyperprolactinemia, tumor functionality, and cerebrospinal fluid exposure were not associated with higher rates of postoperative DI (P > 0.05). Conclusion Pituitary adenoma patients presenting with visual abnormalities, suprasellar extension, or large tumors are at higher risk of developing DI postoperatively. These patients warrant closer postoperative monitoring as well as adequate preoperative counseling to decrease their postsurgical morbidity.

Posterior Reversible Encephalopathy Syndrome Causing Vision Loss After Endoscopic Endonasal Resection of Pituitary Adenoma

BACKGROUNDnPosterior reversible encephalopathy syndrome (PRES) is characterized by headache, altered mental status, visual changes, and seizure combined with brain imaging consistent with cerebral edema without infarction. To the best of our knowledge, we report the first case of PRES after an endoscopic endonasal resection of a pituitary macroadenoma.nnnCASE DESCRIPTIONnA 59-year-old woman was diagnosed with a pituitary macroadenoma, for which she underwent endoscopic endonasal extracapsular resection. After an uneventful initial postoperative recovery, the patient experienced sudden onset of emesis, confusion, vision loss, and severe hypertension. Emergent computed tomography showed normal postoperative changes, with no signs of hematoma or infarction. Magnetic resonance imaging (MRI) showed fluid-attenuated inversion recovery changes in the posterior lobes and thalamus, consistent with PRES. Cerebral angiography showed no vascular abnormalities. Blood pressure control was the primary treatment modality. Within 10 days, the patient was neurologically intact except for right homonymous hemianopsia. Follow-up MRI showed resolution of the PRES with an area of infarction in the left occipital lobe. At 5 years follow-up, the patient reported minimal blurred vision. MRI showed encephalomalacia at the old infarct area, and her visual field testing was unremarkable.nnnCONCLUSIONSnAlthough rare in neurosurgical patients, PRES must be considered in patients who develop acute vision loss and mental status changes associated with hypertension after surgery, including endoscopic endonasal surgery. PRES has the potential for significant neurologic morbidity, if not treated in a timely manner. Early recognition and treatment, with blood pressure control mainly, are therefore mandatory after a surgical complication, such as a postoperative hematoma, has been ruled out.

Endoscopic endonasal pituitary gland hemi-transposition for resection of a dorsum sellae meningioma

A 69-year-old female with incidental diagnosis of a dorsum sellae meningioma had shown significant tumor growth after initial conservative management. The procedure started with a microscopic sublabial transsphenoidal approach to the sella and the suprasellar space. Due to limitations to a safe dissection and removal of the retrosellar component, the surgery was converted to a purely endoscopic endonasal approach with left hemi-transposition of the pituitary gland, followed by drilling of the dorsum sellae and removal of the left posterior clinoid process. A complete tumor resection was achieved, and a multilayer skull base reconstruction was performed without complications. The video can be found here: https://youtu.be/BEolyK-To_A .