A multiport MR-compatible neuroendoscope: spanning the gap between rigid and flexible scopes

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>Rigid endoscopes enable minimally invasive access to the ventricular system; however, the operative field is limited to the instrument tip, necessitating rotation of the entire instrument and causing consequent tissue compression while reaching around corners. Although flexible endoscopes offer tip steerability to address this limitation, they are more difficult to control and provide fewer and smaller working channels. A middle ground between these instruments—a rigid endoscope that possesses multiple instrument ports (for example, one at the tip and one on the side)—is proposed in this article, and a prototype device is evaluated in the context of a third ventricular colloid cyst resection combined with septostomy.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>A prototype neuroendoscope was designed and fabricated to include 2 optical ports, one located at the instrument tip and one located laterally. Each optical port includes its own complementary metal-oxide semiconductor (CMOS) chip camera, light-emitting diode (LED) illumination, and working channels. The tip port incorporates a clear silicone optical window that provides 2 additional features. First, for enhanced safety during tool insertion, instruments can be initially seen inside the window before they extend from the scope tip. Second, the compliant tip can be pressed against tissue to enable visualization even in a blood-filled field. These capabilities were tested in fresh porcine brains. The image quality of the multiport endoscope was evaluated using test targets positioned at clinically relevant distances from each imaging port, comparing it with those of clinical rigid and flexible neuroendoscopes. Human cadaver testing was used to demonstrate third ventricular colloid cyst phantom resection through the tip port and a septostomy performed through the lateral port. To extend its utility in the treatment of periventricular tumors using MR-guided laser therapy, the device was designed to be MR compatible. Its functionality and compatibility inside a 3-T clinical scanner were also tested in a brain from a freshly euthanized female pig.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Testing in porcine brains confirmed the multiport endoscope's ability to visualize tissue in a blood-filled field and to operate inside a 3-T MRI scanner. Cadaver testing confirmed the device's utility in operating through both of its ports and performing combined third ventricular colloid cyst resection and septostomy with an endoscope rotation of less than 5°.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>The proposed design provides freedom in selecting both the number and orientation of imaging and instrument ports, which can be customized for each ventricular pathological entity. The lightweight, easily manipulated device can provide added steerability while reducing the potential for the serious brain distortion that happens with rigid endoscope navigation. This capability would be particularly valuable in treating hydrocephalus, both primary and secondary (due to tumors, cysts, and so forth). Magnetic resonance compatibility can aid in endoscope-assisted ventricular aqueductal plasty and stenting, the management of multiloculated complex hydrocephalus, and postinflammatory hydrocephalus in which scarring obscures the ventricular anatomy.</jats:p></jats:sec>

The endoscope and instruments for minimally invasive neurosurgery

“…The next generation fiberoptic neuroendoscopy with "chip on tip" camera combines the best of both flexible and rigid scopes. They were originally developed for bronchoscopy and provide excellent visualization and flexibility to work in the lamina terminalis, temporal horns, fourth ventricle, etc., which are not easily accessible by rigid scope [77] . Currently, they are more expensive than the traditional rigid endoscopes, and there have been reports of visual and electrical interference when used concurrently with monopolar cautery [78] .…”

Сапфировый Нейрохирургический Зонд Для Аспирации Опухолей Мозга С Демаркацией Границ С Помощью Спектроскопии-=sup=-*-=/Sup=-

“…На рис. 5 показан сапфировый нейрозонд, который может быть использован как в режиме операций на открытом мозге, так и для нейроэндоскопических операций с применением троакаров с инструментальным каналом [66]. Волокна вводятся через боковую проточку зонда, удаленную от рабочего конца инструмента и закрывающуюся стерильным рукавом так, что в прямом контакте с биотканью находится только сапфировый нейрозонд.…”

Minimally Invasive Bilateral Anterior Cingulotomy via Open Minicraniotomy Using a Novel Multiport Cisternoscope: A Cadaveric Demonstration

“…The multiport endoscope used in this study was fabricated in our laboratory and, consequently, is not of comparable optical quality to a commercially produced endoscope. 1 In addition, heat production would need to be studied for the desired type of lesioning device. Furthermore, significant further technical and procedural development would be needed to adapt the proposed method for cisternal stabilization of stimulation electrodes at the ACC and to avoid contamination of recordings from the contralateral cingulate gyrus.…”

“…The endoscope prototype comprises a 7-mm diameter cylindrical body housing 2 imaging ports-1 on the distal tip and 1 on the lateral surface (Figure 3). 1 Imaging at both ports is provided by complementary metal-oxide semiconductor cameras (NanEye, Awaiba Inc, Nürnberg, Germany) and LEDs encased in optically clear silicone. The lateral port contains a 1-mm diameter working channel with a 7-mm radius of curvature.…”