{"id":"ae11c89f-3d0f-4e2a-8d8d-1a87b643426a","slug":"minimizing-cortical-disturbance-to-access-ventricular-subependymoma-a-novel-approach-utilizing-spinal-minimally-invasive-tubular-retractor-system","title":"Minimizing cortical disturbance to access ventricular subependymoma – A novel approach utilizing spinal minimally invasive tubular retractor system","authors":["Eric Klotz","Wendy Towers","Khalid Kurtom"],"abstract":"Background: Subependymomas are rare benign tumors found primarily in the lateral and fourth ventricles. Patients become symptomatic when the tumor obstructs cerebrospinal fluid pathways. We present a novel minimally invasive technique for lateral ventricular subependymoma resection. Case Description: A 57-year-old male presented after a period of progressive ataxia, right upper extremity tremor, and syncopal events. Emergent non-contrast computed tomography of the brain demonstrated a lobulated mass in the left lateral ventricle causing moderate-to-severe obstructive hydrocephalus. Emergent ventriculostomy was placed as a temporizing measure. Subsequent magnetic resonance imaging (MRI) illustrated a large benign appearing mass causing obstruction of the left foramen of Monroe. A small craniotomy was performed utilizing previous ventriculostomy twist hole. The left lateral ventricle was accessed through sequential dilation of ventriculostomy tract using a minimally invasive spine surgery tubular system. Tumor was resected en bloc under microscopic assistance. The patient had an excellent outcome with return to baseline mental status and was discharged from the hospital postoperative day 1. Follow-up MRI demonstrated gross total resection of the mass and decreasing lateral ventricle hydrocephalus with minimal cortical disturbance. Conclusion: A minimally invasive tubular system approach to ventricular tumors can be utilized to minimize cortical resection and brain retraction. Minimally invasive surgery also has the potential to decrease the length of stay and enhance postoperative recovery. Subependymomas are benign intraventricular slow-growing tumors found mostly in the lateral and fourth ventricles.[ 1 ] These rare tumors were first described in 1945 by Scheinker[ 13 ] and are mostly seen in middle-aged men.[ 3 , 4 ] Patients become symptomatic when a tumor reaches 3–5 cm, blocking cerebrospinal fluid (CSF) pathways. Eliyas et al.[ 6 ] presented a case series of ventricular tumor resections utilizing a specialized neuronavigation obturator for dilation through the sulcus. Here, we present a case of a left lateral ventricle pedunculated subependymoma resected through a minimally invasive spine tubular system which is readily available and does not require specialized instrumentation. A 57-year-old male presented to the emergency department after 2 weeks of the right upper extremity tremor, progressive ataxia, and a syncopal event. Neurologic examination was significant only for confusion and a resting tremor of his right upper extremity. Non-contrast brain computed tomography (CT) demonstrated a left lateral ventricle lobulated soft tissue density mass measuring 2.0 cm × 2.2 cm causing moderate-to-severe obstructive hydrocephalus at the foramen of Monroe [ Figure 1a and 1b ]. An emergent ventriculostomy was placed as a temporizing measure. Subsequent magnetic resonance imaging (MRI) illustrated a large benign appearing mass obstructing the left foramen of Monroe [ Figure 2a-f ]. The patient was taken to the operating room for mass resection. (a and b) Computed tomography brain w/o contrast noting lobulated soft tissue density mass left lateral ventricle measuring 2.0 cm × 2.2 cm causing severe obstructive hydrocephalus at the foramen of Monroe. Magnetic resonance imaging brain with gadolinium demonstrating a large benign appearing mass causing obstruction of the left foramen of Monroe, (a) TI hypointense mass, (b) T2 hypointense mass, (c) Flair hyperintense mass with transependymal edema, (d) Axial T1 w/gad hypointense mass without evidence of enhancement, (e) Sagittal T1 w/gad non-enhancing mass obstructing foramen of Monroe, (f) Coronal T1 w/gad non-enhancing mass obstructing lateral ventricle with left ventricle hypertrophy and rightward septal shift. The patient was placed under general anesthesia in a supine position with the head slightly flexed. A two-inch straight incision was made over the left frontal region incorporating the ventriculostomy puncture site [ Figure 3 ]. A small craniotomy was completed, centered over the previous ventriculostomy twist hole. With neuronavigation assistance, bipolar electrocautery and suction were used to follow the ventriculostomy drain to the left lateral ventricle. Minimally invasive spine sequential dilators followed this trajectory to the ventricle to place a 14-mm diameter by 6-cm length minimally invasive spinal tubular retractor [ Figure 4 ]. The operative microscope was then used to complete the operation [Video 1-4]. 2” incision incorporating the ventriculostomy puncture site. 14 mm × 6 cm minimally invasive spinal tubular retractor used for the transcortical exposure of the mass in the left lateral ventricle. A small incision was made into the mass to obtain biopsy. Internal debulking was allowed for manipulation of the mass. A cottonoid covered the Foramen of Monroe to isolate the lateral ventricle in case of intraoperative bleeding. Bipolar electrocautery and micro scissors were used to transect the pedicle from the lateral ventricular wall. The mass was then removed en bloc. The ventricular anatomy was examined to confirm open CSF pathway before removal of the tubular retractor [ Figure 5 ]. No ventricular catheter or drain was placed. Ventricular anatomy, labeled. The patient had immediate return to baseline mental status and was discharged from the hospital postoperative day 1. Follow-up MRI demonstrated gross total resection of the mass and decreased lateral ventricle hydrocephalus with minimal cortical disturbance [ Figure 6a-f ]. Pathology demonstrated a subependymoma with microcystic degeneration, the WHO Grade 1 [ Figure 7a-c] . Immunostains indicated that the lesional cells were positive for GFAP and S-100 [ Figure 7d and 7e ). The proliferating cell fraction was Figure 7f ]. 2 weeks later, the patient had improvement in gait and resolution of tremor. Postoperative magnetic resonance imaging brain w/gad demonstrating total resection of the mass and decreasing lateral ventricle hydrocephalus with minimal cortical disturbance, (a) Axial T1 w/gad with decreased left lateral ventricular hydrocephalus and gross total resection of ventricular mass, (b) Flair demonstrating reduced transependymal edema, (c) Sagittal T1 w/gad with gadolinium with patent foramen of Monroe after complete resection of intraventricular mass, (d) Coronal T1 w/gad illustrating the trajectory of tubular channel through cortex, (e) Sagittal T1 w/gad view of tubular channel through the cortex, (f) Axial flair view minimal cortical disruption. (a-c) Subependymoma with microcystic degeneration, the WHO Grade 1, (d and e) Positive lesional cell GFAP and S-100 immunostains, (f) Proliferating cell KI-67 immunostain fraction <1%.","thumbnailUrl":"https://sni-digital-videos.s3.amazonaws.com/articles/ae11c89f-3d0f-4e2a-8d8d-1a87b643426a/featured/hero-1781563914573.png","publishDate":"2019-06-07T00:00:00.000Z","doi":"10.25259/SNI-25-2019","categories":["General Neurosurgery","Case Report"],"fullTextUrl":"http://surgicalneurologyint.com/wp-content/uploads/2019/06/9351/SNI-10-95.pdf"}