PMC3935219_01
MRI brain (CISS sequence) depicting small vessel (arrow) at the trigeminal nerve juxtapontine segment (a). Post-MVD CT brain demonstrating the Teflon patch (arrow) at the juxtapontine and cisternal segments of the trigeminal nerve (b)
SNI-4-462-g001.jpg
PMC3935219_01_SNI-4-462-g001.jpg
F1
MRI constructive interference in steady state (CISS) sequence [Figure 1]. Management options were offered for the patient, which included percutaneous procedures, radiosurgery, and MVD.
Cyberknife  radiosurgery plan on MRI depicting the dose target and isodense lines
SNI-4-462-g002.jpg
PMC3935219_01_SNI-4-462-g002.jpg
F2
A total dose of 60 Gy prescribed to 76% Isodose line covering 100% of the target, which consisted of a 6-mm length of the left trigeminal nerve cisternal segment [Figure 2].
Intraoperative photos demonstrating the left trigeminal nerve and artery loop at the upper surface of the juxtapontine nerve segment (arrow) (a). The artery loop was isolated from the nerve using Teflon patch (b). Note the trigeminal nerve atrophy, flattening and changes in color as compared with the faciocochlear complex (arrow) (a, b and d). The site of trigeminal nerve biopsy at the midcisternal segment is demonstrated (c)
SNI-4-462-g003.jpg
PMC3935219_01_SNI-4-462-g003.jpg
F3
Intraoperatively, the trigeminal nerve appeared atrophied and flattened with grayish discoloration of the nerve rootlets [Figure 3]. An arterial loop was identified at the superior surface of the juxtpontine trigeminal nerve segment; however, the artery was not causing obvious compression [Figure 3]. Partial sensory sectioning was done and a small nerve rootlets biopsy from the midcisternal nerve segment was taken and submitted for histopathological examination [Figure 3].
Histopathology thick section of the specimen showing abundant collagen fibers (C) where nerve sprouts are embedded. In the center two large and thinly myelinated axons (arrows) have empty axoplasm. Inset: A regenerating axonal cluster. (Toluidine blue. Original magnifications x 400)
SNI-4-462-g004.jpg
PMC3935219_01_SNI-4-462-g004.jpg
F4
The toluidine blue-stained, epoxy-embedded section revealed fibrous tissue (fibrosis) and a few haphazardly arranged and distorted myelinated nerve fibers [Figure 4].
Histopathology slide showing distorted nerve fibers (myelinated axons) surrounded by abundant collagen fibers (letter C). Transmission electron microscopy, original magnification x 1000; bar = 5 mum (a). Some axons have clear axoplasm (open arrows) and others have dense filamentous axoplasm (white arrow). Transmission electron microscopy, original magnification x 1000; bar = 5 mum (b)
SNI-4-462-g005.jpg
PMC3935219_01_SNI-4-462-g005.jpg
F5
Transmission EM revealed variably sized myelinated axons in a marked collagenous background [Figure 5].