Three-dimensional morphology of the superior cerebellar artery running in trigeminal neuralgia

Outcomes After Microvascular Decompression for Sole Arterial Versus Venous Compression in Trigeminal Neuralgia

OBJECTIVE

In most cases of trigeminal neuralgia (TN), the trigeminal nerve is compressed by the arterial vasculature. We sought to address the gap in understanding of pain outcomes in patients with sole arterial versus sole venous compression.

METHODS

We retrospectively reviewed all patients undergoing microvascular decompression at our institution, identifying patients with either sole arterial or venous compression. We dichotomized patients into arterial or venous groups and obtained demographics and postoperative complications for each case. Barrow Neurological Index (BNI) pain scores were collected preoperatively, postoperatively, and at final follow-up, as well as recurrence of pain. Differences were calculated via χ² tests t tests, and Mann-Whitney U Tests. Ordinal regression was used to account for variables known to influence TN pain. Kaplan-Meier analysis was used to determine recurrence-free survival.

RESULTS

Of 1044 patients, 642 (61.5%) had either sole arterial or venous compression. Of these cases, 472 showed arterial compression and 170 showed sole venous compression. Patients in the venous compression group were significantly younger (P < 0.001). Patients with sole venous compression showed worse preoperative (P = 0.04) and final follow-up (P < 0.001) pain scores. Patients with sole venous compression had significantly higher rate of pain recurrence (P = 0.02) and BNI score at pain recurrence (P = 0.04). On ordinal regression, venous compression was found to independently predict worse BNI pain scores (odds ratio, 1.66; P = 0.003). Kaplan-Meier analysis showed a significant relationship between sole venous compression and increased risk of pain recurrence (P = 0.03).

CONCLUSIONS

Patients with TN with sole venous compression show worse pain outcomes after microvascular decompression compared with those with only arterial compression.

Absent Meckel's cave as a possible cause of trigeminal neuralgia: A case report

Trigeminal neuralgia (TN) is a debilitating yet potentially treatable facial pain disorder.TN is difficult to miss clinically, as patients' clinical presentation is often strikingly stereotypical: unilateral, paroxysmal, stimulus-dependent pain involving the trigeminal territory. Magnetic resonance imaging (MRI), which is used for further evaluation of an underlying etiology of TN, most commonly shows neurovascular compression of the trigeminal nerve to be the culprit. Secondary etiologies, though less common, do exist. An absent Meckel's cave with ipsilateral TN was reported in a few case reports and series, and whether an etiological relationship exists is yet to be established. We herein present a case of a 22-year-old female patient who presented with typical TN clinical manifestations. MRI was ordered to assess for the underlying cause and an ipsilateral absent Meckel's cave was the only significant finding. This case report adds to the scarcity of literature highlighting this entity, further larger clinical studies are needed to establish a causal relationship.

How I do it: two-step transposition technique during endoscopic microvascular decompression for trigeminal neuralgia

BACKGROUND

Endoscopic microvascular decompression (eMVD) provides excellent visualization and minimally invasive surgical treatment of trigeminal neuralgia (TN). The transposition technique is desirable for long-term outcomes of TN.

METHOD

A two-step transposition technique is performed during eMVD for TN due to the arch-shaped superior cerebellar artery (SCA). First, the cerebellomesencephalic segment of the SCA is pulled out using oxycellulose balls. Second, the retracted lateral pontomesencephalic segment of the SCA is detached from the trigeminal nerve and is transposed for fixation at the tentorium cerebelli.

CONCLUSION

The two-step transposition technique offers simple, reliable decompression for TN due to the arch-shaped SCA.

Trochlear Nerve Palsy Caused by a Superior Cerebellar Artery Aneurysm

Purpose: We report a case of trochlear nerve palsy caused by a superior cerebellar artery (SCA) aneurysm.Case summary: A 34-year-old woman visited our clinic complaining of distance diplopia and a temporal headache 7 days in duration. She had no previous relevant medical or trauma history. Her visual acuity; intraocular pressure; and pupil, anterior segment, and fundus evaluations were unremarkable. Extraocular muscle examination (EOM) revealed six prism diopters (PD) of right hypertropia in the primary gaze; this worsened when the head was tilted to the right. Brain magnetic resonance imaging revealed a round solid nodule between the temporal lobe and pons; we thus suspected a petrous ridge meningioma. She was referred to our neurosurgery department for meningioma treatment. However, 1 hour later, she visited our emergency room with severe headache and nausea. Brain computed tomography angiography revealed a subarachnoid hemorrhage and a ruptured SCA aneurysm. Emergency coil embolization was successfully performed. Four weeks after surgery, the right hypertropia was slightly decreased. Four months later, the diplopia had disappeared and EOM revealed orthotropia.Conclusions: SCA aneurysms are rare and can be misdiagnosed even after radiological examination. Our case emphasizes that an SCA aneurysm should be considered during the differential diagnosis of patients with diplopia and headache.

Trigeminal neuralgia secondary to onyx embolization of a right occipital arteriovenous malformation

Background:

Trigeminal neuralgia is a debilitating chronic condition characterized by severe recurrent hemifacial pain which is often caused by compression of the trigeminal nerve by an adjacent vessel loop. Microvascular decompression (MVD) surgery is an effective procedure that can lead to full symptomatic relief. Intracranial arteriovenous malformations (AVMs) are primarily congenital abnormalities that may be asymptomatic or manifest as seizures or focal neurologic deficits. They may cause intracranial bleeding and hence are promptly treated, often by endovascular embolization. This procedure is safe but may have a multitude of unpredictable complications.

Case Description:

A 33-year-old female presented with medically refractory trigeminal neuralgia secondary to Onyx embolization of a right occipital AVM 3 years prior. She underwent surgical exploration and MVD of the trigeminal nerve root which was found to be compressed by the previously embolized superior cerebellar artery. The procedure was successful and full symptomatic resolution was immediately achieved.

Conclusion:

Postprocedural trigeminal neuralgia is a procedural complication of Onyx endovascular embolization. It may be treated by MVD surgery regardless of the presence or absence of a compressive vascular loop on imaging.