Reply: The role of neurovascular contact in patients with multiple sclerosis

We thank Dr Montano and Dr Rapisarda for their interest in our recently published study “Neurovascular contact plays no role in trigeminal neuralgia secondary to multiple sclerosis” (1).

Montano and Rapisarda state that our study cannot exclude microvascular decompression (MVD) as a treatment option in patients with trigeminal neuralgia secondary to multiple sclerosis (TN-MS) and that a neurovascular contact (NVC) even without morphological changes of the trigeminal nerve may still play a role in TN-MS (2).

In primary TN patients it is well known that an excellent outcome (complete pain freedom without medication) after MVD is mainly found in patients with classical TN (3).

In our study we did not find any correlation between NVC with morphological changes and the symptomatic side in patients with TN-MS. This does not exclude that surgery could be an option in rare cases with patients with TN-MS which we also state in the final 5 lines of the conclusion-section in the paper. However, based on our findings we do not generally recommend MVD in TN-MS patients.

Montano and Rapisarda refer to a systematic review reporting that 71% of the TN-MS patients who underwent MVD had acute pain relief defined as pain relief at discharge of the hospital (4). We do not agree that firm conclusions can be made by the mentioned study.

Firstly, the studies included in the review were all retrospectively designed and with non-independent assessors of outcome. Secondly, as the authors state more than 25% of the patients with acute pain relief had pain recurrence 24 months after the procedure. Another important aspect, in addition to outcome, is the surgical complications. These have never been reported in a prospective systematic study using independent assessors in TN-MS.

We agree with Montano and Rapisarda that is it difficult to treat patients with TN-MS and that all options should be considered. Meanwhile, one should also keep in mind that a difficult to treat patient with pain should not be exposed to treatments that are not evidence-based. This goes especially for a highly invasive procedure such as MVD. A good example of this dilemma is the treatment of patients with idiopathic persistent facial pain, previously atypical facial pain, a diagnosis that can be notoriously difficult to treat. In our team - including neurologists and neurosurgeons - we no longer consider MVD as an option for these patients based on the complete lack of association to a neurovascular contact (1). In addition, on the basis of our findings we propose that considerations on treatments options should take into account that 1) our study finds no association between the symptomatic side and a neurovascular contact in patients with TN and MS which is completely opposite to classical TN, and 2) there is little high-quality data to support that MVD is efficacious and safe in patients with TN and MS (5). Prospectively designed studies performed by independent investigators are highly warranted to further document the efficacy and complications of MVD in patients with TN-MS.