case_images: PMC3326946_01
case_images: (a, b) Tips of two transparent sheaths with diameters of 6.8 mm (Neuroport  mini size; Olympus Corp., Tokyo) are obliquely cut, and the sheaths are combined with Nelaton tubes (Fr 18) as removal inner tubes. (c) The ports are inserted into the front of the target lesion via an infinity-shaped burr hole under control of the navigation system. (d) Scheme of dual-port technique. The front of the tumor lesion is observed with the rigid endoscope (black tube), with the maximal diameter of 2.7 mm (EndoArm ; Olympus Corp. Tokyo, Japan) through the left port, and the lesion is removed using several surgical instruments (white-gray, blue, and gray bars) via two ports in this scheme
case_images: SNI-3-35-g001.jpg
case_images: PMC3326946_01_SNI-3-35-g001.jpg
case_images: F1
case_images: Tokyo) with Nelaton tubes (Fr 18) as alternative inner tubes were inserted into the front of the target lesion via an infinity-shaped burr hole, under control of the navigation system (StealthStation , Medtronic, Inc., Minneapolis, MN) [Figure 1].
case_images: Endoscopic view of the navigation-guided endoscopic surgery using the dual-port technique. (a) The front of the tumor lesion and the right port are observed with the endoscope though the left port. (b) The bleeding point is coagulated with the bipolar forceps, with sufficient aspiration
case_images: SNI-3-35-g002.jpg
case_images: PMC3326946_01_SNI-3-35-g002.jpg
case_images: F2
case_images: The front of the lesion was observed with a rigid endoscope (EndoArm ; Olympus Corp. Tokyo, Japan) through the left port, and the lesion was removed partially, using one or two surgical tools, through the bilateral ports [Figure 2].
case_images: Magnetic resonance imaging revealed partial resection of the mass lesion after the port surgery. Sagittal views and schematic views on T1-weighted gadolinium enhanced images, before (a and c) and after (b and d) the port surgery, demonstrate heterogenous enhancement of the mass lesion
case_images: SNI-3-35-g003.jpg
case_images: PMC3326946_01_SNI-3-35-g003.jpg
case_images: F3
case_images: MR imaging revealed partial resection of the mass lesion after the surgery [Figure 3].