PMC4901823_01
Magnetic resonance imaging scan, time of flight sequences; (a) coronal section showing the venous loop (black arrow) around the exit of the V nerve (white arrow); (b) axial section, time of flight sequences, showing possible anterior arterial conflict; (c) magnetic resonance venography showing the vein anatomy of the patient: The compressing vein is draining into the superior petrosal complex (white arrow); a possible vascular abnormality (black arrow) is seen into the right cerebellar hemisphere
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F1
A large venous vessel tributary of the petrous vein complex was found close to the nerve, and it was suspected to be responsible for the pain [Figure 1a-c].
(a) Intra-operative view. Large, dilated vein is markedly compressing the trigeminal nerve; the vein appears to drain into the superior petrosal complex, which is partially seen on the right side of the surgical field. (b) Abnormally thickened and dilated vessels occurring in clusters in the cerebellar cortex and subarachnoid space, (H and Eosin, x40); (c) these abnomal vessels show irregular fibrosis (red) and elastosis (black) on an Elastica-van Gieson stain, in keeping with arterialization of venous channels (x100)
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F2
The trigeminal nerve was markedly compressed by a large vein - probably the cerebellopontine vein itself, which was draining into the superior petrosal complex [Figure 2a]. Some abnormal vessels were found in the context of the cerebellar tissue, thus venous angioma/cerebellar arteriovenous malformation (AVM) was suspected, and samples were sent for pathology analysis, which confirmed the same [Figure 2b and c].
Computed tomography head done immediately after the second attempt of microvascular decompression, showing dramatic pontine (a), midbrain and basal temporal (b), posterior thalamus and mesial temporal lobe (c) infarction; craniectomy is noted at the level of the posterior cranial fossa (PCF) together with partial cerebellar lobectomy and clot removal (d)
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F3
This showed massive left cerebellar, brainstem, thalamic, and temporal lobe infarction and hemorrhage, with concomitant developing hydrocephalus [Figure 3].