Dual-trajectory Approach for Simultaneous Cyst Fenestration and Endoscopic Third Ventriculostomy for Treatment of a Complex Third Ventricular Arachnoid Cyst.

Open Access Technical Report DOI: 10.7759/cureus.253 Dual-trajectory Approach for Simultaneous Cyst Fenestration and Endoscopic Third Ventriculostomy for Treatment of a Complex Third Ventricular Arachnoid Cyst Allen L. Ho 1, Arjun V. Pendharkar2, Eric S. Sussman 3, Vinod K. Ravikumar4, Gordon H. Li5 1. Department of Neurosurgery, Stanford University School of Medicine 2. Department of Neurosurgery, Stanford University Medical Center 3. Department of Neurosurgery, Stanford School of Medicine/Stanford University Medical Center 4. Department of Neurosurgery, Stanford University Medical Center 5. Department of Neurosurgery, Stanford University Medical Center  Corresponding author: Allen L. Ho, Disclosures can be found in Additional Information at the end of the article Abstract Objectives: We present a case of a multiloculated third ventricular arachnoid cyst to describe a novel technique for definitive management of these lesions via direct endoscopic fenestration and CSF diversion utilizing separate trajectories that offers superior visualization and avoids forniceal injury. Methods and Results: We present a case of a 33-year-old woman with progressive headache and worsened vision, a known history of a multiloculated third-ventricular arachnoid cyst, and imaging findings consistent with cyst expansion and worsened obstructive hydrocephalus. We then describe the dual-trajectory approach for simultaneous cyst fenestration and endoscopic third ventriculostomy that ultimately resulted in successful treatment of her cyst and hydrocephalus. Conclusions: Dual-trajectory endoscopic approach utilizing double burr holes should be considered when addressing lesions of the third ventricle causing obstructive hydrocephalus. Categories: Neurosurgery, Healthcare Technology Keywords: arachnoid cyst, endoscopic third ventriculostomy, burrhole, hydrocephalus, image guidance Introduction Review began 01/05/2015 Review ended 03/02/2015 Published 03/05/2015 © Copyright 2015 Ho et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 3.0., which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Estimates of the prevalence of arachnoid cysts in adults vary anywhere from 0.2 to 1.7% [1]. Cysts located in the third ventricle can cause obstructive hydrocephalus as a result of compression or direct occlusion of the cerebral aqueduct or foramen of Monro. They have also been shown to cause endocrine dysfunction and/or visual impairment via mass effect on the optic tracts or pituitary axis. CSF diversion via implanted shunting systems is effective at addressing the hydrocephalus associated with these cysts; however, these systems are associated with both mechanical and infectious complications, often necessitating multiple revisions [2-8]. While transcallosal craniotomy can achieve definitive treatment of the cyst via fenestration and/or resection and can aid in avoiding shunt dependence, the morbidity of an open approach is not insignificant and includes damage to crucial vascular structures, disconnection syndromes from splitting the corpus callosum, and damage to the fornices and subcortical nuclei [9]. Several studies have now described successful management of arachnoid cysts with endoscopic approaches [10-13]. However, in many of these cases, especially with multi-loculated lesions, the How to cite this article Ho A L, Pendharkar A V, Sussman E S, et al. (2015-03-05 13:52:22 UTC) Dual-trajectory Approach for Simultaneous Cyst Fenestration and Endoscopic Third Ventriculostomy for Treatment of a Complex Third Ventricular Arachnoid Cyst. Cureus 7(3): e253. DOI 10.7759/cureus.253 need for revision fenestrations or permanent CSF diversion was still necessary [9, 14-15]. Because of this, emphasis has been placed on considering a combination of procedures to minimize recurrence and achieve successful treatment of these complex lesions [13, 16-18]. We describe a novel technique for definitive management of these lesions via direct endoscopic fenestration and CSF diversion utilizing separate trajectories that avoids forniceal injury. Case presentation The patient is a 33-year-old woman who presented with six months of progressive headaches (worse in the morning) and blurred vision. She had a history of galactorrhea and a diagnosis of hydrocephalus and a third-ventricular cyst based off of a MRI scan done five years prior, but ultimately did not seek any follow-up care (Figure 1). Her neurologic exam was unremarkable except for papilledema. MRI demonstrated worsened ventriculomegaly and an enlarged complex cystic structure within the third ventricle consistent with an arachnoid cyst (Figure 2). The patient underwent a dual-trajectory, double burr hole approach for simultaneous cyst biopsy and fenestration and endoscopic third ventriculostomy (ETV). Final pathology was consistent with an arachnoid cyst. Postoperatively, the patient did well. All her symptoms resolved, and she remained symptom-free at her six-month follow-up. FIGURE 1: Patient imaging five years prior to initial presentation T1 weighted, non-contrast, sagittal brain MRI demonstrating a multi-loculated third ventricular cystic structure (arrows). 2015 Ho et al. Cureus 7(3): e253. DOI 10.7759/cureus.253 2 of 8 FIGURE 2: Patient imaging at presentation (Left) T2 weighted sagittal brain MRI demonstrating an enlarged multi-loculated cystic structure located in the third ventricle with worsened ventriculomegaly. (Right) T1 weighted non-contrast coronal brain MRI demonstrating an enlarged multi-loculated cystic structure located in the third ventricle with worsened ventriculomegaly. Technical Report Several neurosurgical treatment options exist for hydrocephalus secondary to third-ventricular arachnoid cysts, including CSF diversion via a ventriculoperitoneal shunt, open surgical resection of the cyst, or a less invasive endoscopic approach. We elected to utilize a double burr hole endoscopic approach combined with image guidance in order to address the cyst via direct endoscopic fenestration and create a channel for CSF diversion via an endoscopic third ventriculostomy (ETV). Informed patient consent was obtained prior to treatment. After endotracheal intubation, the patient was placed supine on the operating table under general anesthesia. The head was secured in a gel donut in the supine position. The StealthStation® AxiEMTM frameless image guidance system (Medtronic, Minneapolis, MN, USA) was initiated with CT imaging and facial registration. A standard trajectory was planned with the entry point at Kocher’s point for the ETV. However, the approach to the cyst necessitated a more anteriorly placed entry point so that the endoscope could be directed posteriorly to the cyst without stretching the fornices. The second entry point was determined utilizing the trajectory view while planning to op (...truncated)