Clinical characteristics, neuroanatomical findings and efficacy of medical and surgical treatment of symptomatic trigeminal neuralgia - a systematic prospective study of 60 consecutive patients

Background Among patients with TN, approximately 15% has secondary TN caused by another underlying condition such as multiple sclerosis or a tumor. Studies of classical TN patients have shown a strong association between a severe NVC of the trigeminal nerve and the painful side. This association has been less investigated in STN.

There are no previous systemic and prospective studies of the underlying causes, characteristics and treatment response of patients with STN. Most existing studies on STN have various methodological drawbacks as inclusion was not prospective, diagnosis was not consistent with international guidelines, imaging techniques were not adequately advanced at the time of publication and evaluation of treatment efficacy was not performed by evaluators independent of the neurosurgeon.

Aims

1) To describe the clinical characteristics, the neuroanatomical findings using 3.0 Tesla MRI, and the efficacy of medical and surgical treatment in STN

Hypotheses

1. In STN, there is a correlation between demylinating brainstem plaques and presence and degree of neurovascular contact of the trigeminal nerve ipsilateral to the painful side
2. The efficacy of medical and surgical treatment of STN is comparable to the efficacy in patients with classical trigeminal neuralgia

Power calculations Sample size depends on the number of patients in the inclusion period. The estimated number of included patients is at least 60 patients.

Methods Data have been collected prospectively since 2012 based on semi-structured interview forms completed at out-patient visits at the Danish Headache Center. The efficacy of medical and surgical treatment was also documented prospectively by structured interviews. Efficacy of surgical treatment was evaluated by independent assessors.

All patients had a 3.0 Tesla MRI with a special protocol adapted for the trigeminal nerve and the brainstem.

Ethical considerations The treatment of patients with STN will not differ from the usual treatment and decision-taking.

Inclusion Criteria:

• Diagnosis of secondary trigeminal neuralgia attributed to multiple sclerosis

Clinical cohort of patients diagnosed with secondary trigeminal neuralgia attributed to multiple sclerosis at the Danish Headache Center