Preoperative demonstration of the neurovascular compression characteristics with special emphasis on the degree of compression, using high-resolution magnetic resonance imaging: a prospective study, with comparison to surgical findings, in 100 consecutive patients who underwent microvascular decompression for trigeminal neuralgia.
OBJECTIVE
Surgical outcome after microvascular decompression (MVD) for primary trigeminal neuralgia (TN) has been demonstrated as being related to the characteristics of the neurovascular compression (NVC), especially to the degree of compression exerted on the root. Therefore, preoperative determination of the NVC features could be of great value to the neurosurgeon, for evaluation of conflicting nature, exact localization, direction and degree of compression. This study deals with the predictive value of MRI in detecting and assessing features of vascular compression in 100 consecutive patients who underwent MVD for TN.


METHODS
The study included 100 consecutive patients with primary TN who were submitted to a preoperative 3D MRI 1.5 T with T2 high-resolution, TOF-MRA, and T1-Gadolinium. Image analysis was performed by an independent observer blinded to the operative findings and compared with surgical data.


RESULTS
In 88 cases, image analysis showed NVC features that coincided with surgical findings. There were no false-positive results. Among 12 patients that did not show NVC at image analysis, nine did not have NVC at intraoperative observation, resulting in three false-negative cases. MRI sensitivity was 96.7% (88/91) and specificity 100% (9/9). Image analysis correctly identified compressible vessel in 80 of the 91 cases and degree of compression in 77 of the 91 cases. Kappa-coefficient predicting degree of root compression was 0.746, 0.767, and 0.86, respectively, for Grades I (simple contact), II (distortion), and III (marked indentation; p < 0.01).


CONCLUSIONS
3D T2 high-resolution in combination with 3D TOF-MRA and 3D T1-Gadolinium proved to be reliable in detecting NVC and in predicting the degree of the root compression.
Leal
Paulo Roberto Lacerda
PR
Department of Neurosurgery, University of Lyon, Lyon, France, prlleal@hotmail.com.
Hermier
Marc
M
Froment
Jean Claude
JC
Souza
Miguel Angelo
MA
Cristino-Filho
Gerardo
G
Sindou
Marc
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002536:Cerebral Arteries / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D002560:Cerebrovascular Circulation / Q000502:physiology; D002561:Cerebrovascular Disorders / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D019299:Decompression, Surgical / Q000379:methods; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods*; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014276:Trigeminal Nerve / Q000098:blood supply* / Q000473:pathology* / Q000503:physiopathology; D014277:Trigeminal Neuralgia / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D014656:Vascular Surgical Procedures / Q000379:methods