PMC3356991_01
Vascular compression of the trigeminal nerve. (a) The superior cerebellar artery (SCA) can present an abnormal elongated loop causing compression on the trigeminal nerve (TN). This is the most common offending vessel of trigeminal neuralgia. (b) Clinical pathologic correlation of vascular compression on the TN: Rostral compression of the TN causes lower facial trigeminal neuralgia (V3), medial or lateral compression causes V2 pain, and compression of the caudal site causes V1 trigeminal neuralgia. The present case had a rostral-medial compression by the SCA (red arrow). PCA, posterior cerebral artery
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F1
TN [Figure 1]. The pain attacks had initiated 5 years ago and during the last year had become resistant to the medical treatment. This is the nerve area corresponding to the anatomical location of the nerve fibers of the third branch [Figure 1b]. Therefore, the SCA was predicted as the offending vessel and the patient was scheduled for surgery.
Preoperative (a) and postoperative (b) 3D FIESTA and 3D TOF MOTSA MRI scans. (a1) Transverse 3D FIESTA image at the level of pons. The small rounded structure medial to the trigeminal nerve (TN) corresponds to the right superior cerebellar artery (SCA). (a2) The SCA loop can be easily identified on the sagittal reformatted 3D TOF MOTSA image. Sagittal (a3) and coronal (a4) reformatted 3D FIESTA images demonstrate rostral-medial compression of the TN by the SCA loop. Postoperative sagittal (b1) and coronal (b2) reformatted 3D FIESTA images reveal the proper position of the Teflon implant (white arrowhead) between the SCA and the TN. PCA, posterior cerebral artery
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F2
It was situated properly between the TN and the SCA, and its signal intensity was intermediate between that of cerebrospinal fluid and neurovascular structures [Figure 2b].
Operative photographs. (a) The patient was placed in the lateral position with an axillary roll and a three-point head holder attached to the head. The single line indicates the skin incision and the double line, the location of the transverse and sigmoid sinus. (b) The suboccipital retrosigmoid craniectomy was extended to the sigmoid and lateral sinuses. (c) The rostral-medial compression of the trigeminal nerve (TN) by the superior cerebellar artery (SCA) was confirmed at surgery. (d) The SCA loop was mobilized away from the nerve placing multiple Teflon felt implants (*) that were held in place with fibrin glue
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F3
An MVD was performed via a right retromastoid craniotomy to explore the root entry zone of the affected nerve [Figure 3a, b]. The SCA loop configuration and the point of neural compression were both identical to the neuroradiological findings observed on the FIESTA and MOTSA MRI sequences [Figure 3c].