The pathophysiology of trigeminal neuralgia (TN) in patients without neurovascular compression (NVC) is not completely understood. The objective of this retrospective study was to evaluate the hypothesis that TN patients without NVC differ from TN patient with NVC with respect to brain anatomy and demographic characteristics.
Six anatomical brain measurements from high-resolution brain MR images were tabulated; anterior-posterior (AP) prepontine cistern length, cerebellopontine angle (CPA) cistern volume, nerve-to-nerve distance, symptomatic nerve length, pons volume, and posterior fossa volume were assessed on OsiriX. Brain MRI anatomical measurements from 232 patients with either TN type 1 or TN type 2 (TN group) were compared with measurements obtained in 100 age- and sex-matched healthy controls (control group). Two-way ANOVA tests were conducted on the 6 measurements relative to group and NVC status. Bonferroni adjustments were used to correct for multiple comparisons. A nonhierarchical k-means cluster analysis was performed on the TN group using age and posterior fossa volume as independent variables.
Within the TN group, females were found to be younger than males and less likely to have NVC. The odds ratio (OR) of females not having NVC compared to males was 2.7 (95% CI 1.3–5.5, p = 0.017). Patients younger than 30 years were much less likely to have NVC compared to older patients (OR 4.9, 95% CI 1.3–18.4, p = 0.017). The mean AP prepontine cistern length and symptomatic nerve length were smaller in the TN group than in the control group (5.3 vs 6.5 mm and 8.7 vs 9.7 mm, respectively; p < 0.001). The posterior fossa volume was significantly smaller in TN patients without NVC compared to those with NVC. A TN group cluster analysis suggested a sex-dependent difference that was not observed in those without NVC. Factorial ANOVA and post hoc testing found that findings in males without NVC were significantly different from those in controls or male TN patients with NVC and similar to those in females (female controls as well as female TN patients with or without NVC).
Posterior fossa volume in males was larger than posterior fossa volume in females. This finding, along with the higher incidence of TN in females, suggests that smaller posterior fossa volume might be an independent factor in the pathophysiology of TN, which warrants further study.
ABBREVIATIONSAP = anterior-posterior; BFFE = balanced fast field echo; CPA = cerebellopontine angle; IN = internal neurolysis; MVD = microvascular decompression; NVC = neurovascular compression; TN = trigeminal neuralgia; TN1 = TN type 1; TN2 = TN type 2.
CaranciG, MercurioA, AltieriM, Di PieroV: Trigeminal neuralgia as the sole manifestation of an Arnold-Chiari type I malformation: case report. 48:625–627, 20081819430110.1111/j.1526-4610.2007.01029.x)| false
HorínekD, BrezováV, NimskyC, BelsanT, MartinkovicL, MasopustV, : The MRI volumetry of the posterior fossa and its substructures in trigeminal neuralgia: a validated study. 151:669–675, 20091935020410.1007/s00701-009-0283-8)| false
KakizawaY, SeguchiT, KodamaK, OgiwaraT, SasakiT, GotoT, : Anatomical study of the trigeminal and facial cranial nerves with the aid of 3.0-tesla magnetic resonance imaging. 108:483–490, 200810.3171/JNS/2008/108/3/048318312095)| false
KawanoYMaeharaTOhnoK: Validation and evaluation of the volumetric measurement of cerebellopontine angle cistern as a prognostic factor of microvascular decompression for primary trigeminal neuralgia. Acta Neurochir (Wien)156:1173–11792014
KawanoY, MaeharaT, OhnoK: Validation and evaluation of the volumetric measurement of cerebellopontine angle cistern as a prognostic factor of microvascular decompression for primary trigeminal neuralgia. 156:1173–1179, 20142466343610.1007/s00701-014-2064-2)| false
LealPRBarbierCHermierMSouzaMACristino-FilhoGSindouM: Atrophic changes in the trigeminal nerves of patients with trigeminal neuralgia due to neurovascular compression and their association with the severity of compression and clinical outcomes. J Neurosurg120:1484–14952014
LealPR, BarbierC, HermierM, SouzaMA, Cristino-FilhoG, SindouM: Atrophic changes in the trigeminal nerves of patients with trigeminal neuralgia due to neurovascular compression and their association with the severity of compression and clinical outcomes. 120:1484–1495, 201410.3171/2014.2.JNS13128824745706)| false
PariseMAciolyMARibeiroCTVincentMGasparettoEL: The role of the cerebellopontine angle cistern area and trigeminal nerve length in the pathogenesis of trigeminal neuralgia: a prospective case-control study. Acta Neurochir (Wien)155:863–8682013
PariseM, AciolyMA, RibeiroCT, VincentM, GasparettoEL: The role of the cerebellopontine angle cistern area and trigeminal nerve length in the pathogenesis of trigeminal neuralgia: a prospective case-control study. 155:863–868, 20132322451210.1007/s00701-012-1573-0)| false
RascheD, KressB, StippichC, NennigE, SartorK, TronnierVM: Volumetric measurement of the pontomesencephalic cistern in patients with trigeminal neuralgia and healthy controls. 59:614–620, 20061695504310.1227/01.NEU.0000228924.20750.D4)| false
SindouMHoweidyTAcevedoG: Anatomical observations during microvascular decompression for idiopathic trigeminal neuralgia (with correlations between topography of pain and site of the neurovascular conflict). Prospective study in a series of 579 patients. Acta Neurochir (Wien)144:1–132002
SindouM, HoweidyT, AcevedoG: Anatomical observations during microvascular decompression for idiopathic trigeminal neuralgia (with correlations between topography of pain and site of the neurovascular conflict). Prospective study in a series of 579 patients. 144:1–13, 200210.1007/s701-002-8269-4)| false
ThanKD, SharifpourM, WangAC, ThompsonBG, PandeyAS: Chiari I malformation manifesting as bilateral trigeminal neuralgia: case report and review of the literature. 82:1058–1059, 20112108426210.1136/jnnp.2009.196121)| false