Acta Neurochirurgica

, Volume 160, Issue 5, pp 971–976 | Cite as

Role of the petrous ridge and angulation of the trigeminal nerve in the pathogenesis of trigeminal neuralgia, with implications for microvascular decompression

  • Andrei Brinzeu
  • Chloé Dumot
  • Marc Sindou
Original Article - Functional



Vascular compression is the main pathogenetic factor in apparently primary trigeminal neuralgia; however some patients may present with clinically classical neuralgia but no vascular conflict on MRI or even at surgery. Several factors have been cited as alternative or supplementary factors that may cause neuralgia. This work focuses on the shape of the petrous ridge at the point of exit from the cavum trigeminus as well as the angulation of the nerve at this point.


Patients with trigeminal neuralgia that had performed a complete imagery workup according to our protocol and had microvascular decompression were included as well as ten controls. In all subjects, the angle of the petrous ridge as well as the angle of the nerve on passing over the ridge were measured. These were compared from between the neuralgic and the non-neuralgic side and with the measures performed in controls.


In 42 patients, the bony angle of the petrous ridge was measured to be 86° on the neuralgic side, significantly more acute than that of controls (98°, p = 0.004) and with a trend to be more acute than the non-neuralgic side (90°, p = 0.06). The angle of the nerve on the side of the neuralgia was measured to be on average 141°, not significantly different either from the other side (144°, p = 0.2) or from controls (142°, p = 0.4). However, when taking into account the grade of the conflict, the angle was significantly more acute in patients with grade II/III conflict than on the contralateral side, especially when the superior cerebellar artery was the conflicting vessel.


This pilot study analyzes factors other than NVC that may contribute to the pathogenesis of the neuralgia. It appears that aggressive bony edges may contribute—at least indirectly—to the neuralgia. This should be considered for surgical indication and conduct of surgery when patients undergo MVD.


Trigeminal neuralgia Trigeminal nerve Microvascular decompression surgery Pathophysiology Neuroimaging 


Author contribution

Andrei Brinzeu: substantial contributions to the conception and design, and acquisition of data, and analysis and interpretation of data; statistical analysis; drafting the article or revising it critically for important intellectual content; and final approval of the version to be published. Chloé Dumot: substantial contributions to the acquisition of data and analysis of data, proofing the article, and approval of the final version to be published. Marc Sindou: substantial contributions to the conception and design and interpretation of data, drafting the article, and revising it critically for important intellectual content; revising the article; and approval of the final version to be published.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in this study were in accordance with the ethical standards of the institutional research committee (Comithee d’ethique de l’etablissement, Hopital Neurologique de Lyon) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

This was an imagery study performed with clinical data collected from patient files collected prospectively. For this type of study, formal consent is not required. All patients, however, gave informed consent for the procedure and the study.


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Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Université de Lyon 1LyonFrance
  2. 2.Université de Médecine et Pharmacie « Victor Babes » TimişoaraTimișoaraRomania
  3. 3.Department of NeurosurgeryNeurological Hospital LyonLyonFrance
  4. 4.Groupe ELSAN, Clinique BretéchéNantesFrance

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