Preoperative three-dimensional diagnosis of neurovascular relationships at the root exit zones during microvascular decompression for hemifacial spasm

• Published in: World neurosurgery 2016-08, Vol.92, p.171-178
• Main Authors: Ohtani, Keisuke, Mashiko, Toshihiro, Oguro, Keiji, Takemura, Atsuhito, Hatayama, Toru, Sasaki, Tatsuya, Watanabe, Eiju
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Facial Nerve - diagnostic imaging; Facial Nerve - surgery; Female; Hemifacial spasm; Hemifacial Spasm - diagnostic imaging; Hemifacial Spasm - surgery; Humans; Imaging, Three-Dimensional - methods; Magnetic Resonance Angiography; Magnetic Resonance Imaging; Male; Microvascular decompression; Microvascular Decompression Surgery - methods; Middle Aged; Nerve Compression Syndromes - etiology; Neurosurgery; Preoperative Care; Three-dimensional surgical simulation; Treatment Outcome
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2016.05.005

Abstract Objective Hemifacial spasm occurs when a blood vessel compresses against an area near the root exit zone of the facial nerve. Developments in diagnostic neuroimaging has allowed three-dimensional (3D) observation of artery and nerve locations, an effective aid for treatment selection. However, an accurate interpretation of the 3D data remains challenging because imaging representations of complex small vessels are drowned out by noise. We utilized a noise elimination method to analyze artery and nerve locations and to determine their 3D relationship. Methods Fifteen patients treated for hemifacial spasm were included. Images fused from three modalities of MRI, 3D computed tomography, and angiography were used as source images. Using the images, models of the nerve and candidate vessels were created and displayed in 3D to observe how the arteries were compressing the nerve and to identify the portions of the offending vessels that were closest to the nerve. These preoperative results were then compared with operative field observations during surgery. 3D models of the unaffected side were created and evaluated as controls. Results We were able to confirm that these models were accurate reconstructions of the source images as the tubular nerve and artery cross-sections showed good alignment onto MRI axial slice images. The preoperative diagnoses of the compression sites and offending arteries all matched intraoperative findings. Conclusions An accurate identification of the offending arteries and compression sites was possible, and this method is anticipated to offer effective means of preoperative simulation.