Neural connections between the nervus intermedius and the facial and vestibulocochlear nerves in the cerebellopontine angle: an anatomic study

Case Report: Direct Visualization of the Nervus Intermedius During the Microvascular Decompression Procedure: Should We Take It Seriously?

Background: Nervus intermedius neuralgia (NIN), known as geniculate neuralgia (GN), is an uncommon cranial nerve disease caused by an offending vessel compressing the nervus intermedius (NI). Microvascular decompression (MVD) has now become a valued treatment approach for NIN because it can resolve neurovascular conflict (NVC) at the root entry zone of the NI. In the era of continuously optimizing and improving the surgical technique of MVD, further minimization of all possible postoperative complications is not only welcome but also necessary.

Objective: The aim of this work is to assess the postoperative outcome of direct visualization of the NI during the MVD procedure.

Methods: This study retrospectively reviewed the clinical records of a group of seven consecutive patients with NIN who underwent MVD in the period of 2013–2020 in our clinic and 16 studies reported NIN patients who underwent MVD in the period of 2007–2020.

Results: In total, 91.3% of all patients experienced immediate and complete relief of cranial neuralgia after MVD. Six of 23 patients have experienced direct visualization of the NI intraoperatively, and 66.7% of those patients had complications such as facial paralysis, dysacousia, or a combination of these conditions postoperatively. Slight surgical approach-related complications such as complaints associated with excessive drainage of cerebrospinal fluid (CSF), nausea and vertigo, and delayed wound union were observed in 80% of the remaining 15 patients, and these symptoms are totally relieved in the telephone and outpatient follow-up after 6 months.

Conclusion: Our case series shows that MVD produced immediate pain relief in the majority of NIN patients. MVD carries surgical risk, especially in patients who experience direct visualization of the NI after mechanical stretch and blunt dissection in surgical procedures. Attempts to avoid mechanical stretch and blunt dissection of the compressed nerve were important for intraoperative neuroprotection, especially facial nerve protection

Microvascular Decompression of the VII/VIII Cranial Nerve Complex for the Treatment of Intermediate Nerve Neuralgia: A Retrospective Case Series

BACKGROUND

Intermediate nerve neuralgia (INN) is a rare and often overlooked form of primary otalgia. The pathophysiological mechanism is unknown, although one of the possible contributing factors is a neurovascular conflict at the root entry zone of the intermediate nerve. The pain can be severely debilitating, and the palette of treatment options is small.

OBJECTIVE

To assess the outcome of microvascular decompression (MVD) of the VII/VIII cranial nerve complex for treating INN.

METHODS

We retrospectively reviewed the records of a group of 8 consecutive patients with INN who underwent MVD of the VII/VIII cranial nerve complex in the period 1994 to 2015.

RESULTS

In total, 7 of the 8 patients experienced almost immediate and complete relief of pain, which remained at long-term follow-up (mean 35 mo ± 24 mo, range 8-84 mo). Postoperatively, 1 patient had a cerebrospinal fluid (CSF) leak, 3 patients experienced permanent ipsilateral hearing loss, and 3 patients had temporary complaints associated with excessive drainage of CSF.

CONCLUSION

This study suggests MVD as a valid treatment for medically refractory INN. MVD carries surgical risk, but given the severity of complaints of these patients, we believe the treatment benefits outweigh the associated complications.