Case ReportA Novel Dissection Method Using a Flexible Neuroendoscope for Resection of Tumors Around the Aqueduct of Sylvius
Introduction
Tumors in the posterior third ventricle are rare and clinically challenging to resect because of their highly internalized position; the third ventricle is surrounded by the midbrain, thalamus, pineal gland, and great vein of Galen. Damaging these structures may lead to several neurologic impairments. Further, lesions in these sites can often result in hydrocephalus. The operation for this lesion is necessary to resect tumors and to perform third ventriculostomy for preventing hydrocephalus. Several techniques and tools have been proposed for tumor removal in this region. Recently, endoscopic surgery has developed significantly, and many authors have reported tumor biopsy or resection in this region while performing an endoscopic third ventriculostomy (ETV).1, 2 Endoscopic surgery may be less invasive than microsurgery in resecting deep intraventricular tumors. In many of these reports, a rigid endoscopy with a trans-Monro approach has been used. However, in this method, the foramen of Monro limits the trajectory both anteriorly and posteriorly.3 Flexible endoscopy has a large range of movement in the ventricles and can easily reach from the tuber cinereum to the aqueduct of Sylvius via a single 10-mm burr hole without burdening the foramen of Monro or other periventricular structures.3 However, until now, there have been few reports of tumor resection using a flexible endoscope. In the current report, we present a new method of tumor dissection by flexible neuroendoscopy through 2 illustrative cases.
Section snippets
Operative Procedure
We used a flexible endoscope (VEF-2 [Olympus, Tokyo, Japan]), which is 4 mm in diameter, with a 1.5-mm working channel and 6-mm sheath (NeuroPort MINI [Olympus]). First, we inserted the flexible scope into the frontal horn through a right frontal burr hole, which was located approximately 10–11 cm superior to the nasion (approximately 1–2 cm anterior to the coronal suture) and 2 cm from the midline (pupil line). This burr hole position is suitable for both third ventriculostomy and manipulation
Discussion
Tumor resection around the aqueduct of Sylvius is difficult because of its anatomic position. In microscopic surgery, the approaches typically used for the posterior half of the third ventricle and the pineal region are the occipital transtentorial approach, the infratentorial approach, and the transcallosal approach. However, these approaches have some risks, such as hemianopia, eye movement disturbances, and cognitive decline.4, 5 In addition to creating a lesion in the posterior half of the
Conclusions
By using a flexible endoscope for tumor dissection, resection of a tumor without a neck, which cannot be removed through aspiration alone, becomes possible. To our knowledge, the presented cases are the first to describe the effectiveness of complete resection of a tumor in the third ventricle using flexible endoscopy.
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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.