[Volumetric measurement of the posterior fossa and its components using magnetic resonance imaging in idiopathic trigeminal neuralgia].
BACKGROUND
The neurovascular conflict is now considered an unquestionable dogma in the pathophysiology of idiopathic trigeminal neuralgia (ITN). However, there are more and more papers that provide information about other factors that promote such conflict or neuralgia itself. AIMS. To measure the volume of the substructures of the posterior fossa in patients with ITN and controls and to investigate the association between a reduced volume of these structures and the incidence of ITN.


METHODS
In 20 patients with unilateral ITN and 20 healthy participants, high resolution 1.5 T magnetic resonance imaging scans including axial and coronal sequences T2-weighted with a slice thickness of 1 mm were performed with the aim of a volumetric study of pontomesencephalic cistern, Meckel's cave and trigeminal nerve.


RESULTS
Measuring the pontomesencephalic cistern on each side of the midline, the volume of the affected side cistern was significantly lower than the healthy side one in patients with ITN (p = 0.004) and also when compared with controls hemicisterns. No significant differences in the Meckel's cave nor the trigeminal nerve were found. The incidence of neurovascular conflict was also studied resulting in 10% of patients with ITN where the conflict was not identified.


CONCLUSIONS
Our data support the theory that a small volume of the posterior fossa cisterns containing the trigeminal nerve may increase the incidence of ITN.
Secretaría de Neurocirugía, Hospital General Universitario de Alicante, Pintor Baeza s/n, Alicante, Spain. jabarca80@hotmail.com
Javier
J
Abarca-Olivas
Eloísa
E
Feliu-Rey
Angel P
AP
Sempere
José
J
Sanchez-Payá
Elena
E
Baño-Ruiz
Miguel Angel
MA
Caminero-Canas
Juan
J
Nieto-Navarro
Carlos
C
Botella-Asunción
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012886:Skull / Q000033:anatomy & histology* / Q000473:pathology; D014276:Trigeminal Nerve / Q000033:anatomy & histology* / Q000473:pathology; D014277:Trigeminal Neuralgia / Q000473:pathology*