Surgical Management of Trigeminal Neuralgia Induced by Brainstem Infarct: A Systematic Review of the Literature

Microvascular Decompression for Trigeminal Neuralgia Caused by Vascular Compression on the Trigeminal Sensory Nucleus and Descending Trigeminal Tract

BACKGROUND

Trigeminal neuralgia (TN) is characterized by paroxysmal episodes of severe shocklike orofacial pain typically resulting from arterial compression on the trigeminal root entry zone. However, neurovascular conflict in more proximal parts of the trigeminal pathway within the pons is extremely rare.

METHODS

The authors present a case of microvascular decompression for TN caused by dual arterial compression on the dorsolateral pons, along with a brief literature review.

RESULTS

Our patient was a 74-year-old man with episodic left-sided facial stabbing pain. Brain magnetic resonance imaging revealed a dual arterial compression on dorsolateral pons, the known site of the trigeminal sensory nucleus and descending trigeminal tract. Microvascular decompression was performed via a retrosigmoid approach. Complete pain relief and partial improvement of the facial hypesthesia were achieved immediately after surgery and the Barrow Neurological Institute (BNI) pain intensity score improved from V to I, and the BNI hypesthesia score decreased from III to II within a month following surgery. The literature review identified 1 case of TN secondary to an arteriovenous malformation in root entry zone with lateral pontine extension. One month following partial coagulation of the draining vein, the patient was reportedly able to reduce medication dosage by half to achieve an improvement of BNI pain intensity score from V to IIIa.

CONCLUSIONS

Neurovascular compression in the trigeminal tract and nucleus is a rare but potential cause of TN. A thorough investigation of the trigeminal pathway should be considered during preoperative evaluation and intraoperative inspection, particularly if no clear offending vessel is identified.

Stereotactic Radiosurgery for Medically Refractory Trigeminal Neuralgia Secondary to Stroke: A Systematic Review and Clinical Case Presentation

BACKGROUND

Trigeminal neuralgia (TN) is a paroxysmal, unilateral, brief, shock-like pain in ≥1 divisions of the trigeminal nerve. It can result from multiple causes; however, TN secondary to stroke is very rare.

METHODS

We present the case of TN secondary to pontine infarction treated with incremental doses of neuropathic pain medication for >5 years before conservative management failed. He was then treated with stereotactic radiosurgery (SRS). Additionally, we conducted a systematic review using standard PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines for all the cases of TN with brainstem stroke from 1976 to 2022.

RESULTS

Our patient was an 82-year-old man. Magnetic resonance imaging demonstrated a pontine lesion consistent with stroke. The Barrow Neurological Institute (BNI) score at presentation was 5. He received a marginal dose of 60 Gy to the 80% isodose line in a single fraction to a volume of 0.05 cm3. The immediate post-treatment BNI score was 0 and remained at 0 for 3 months, when he experienced recurrence. The recurrence was treated with oxcarbazepine. His pain remained well controlled with a lower dose of oxcarbazepine, and he had no adverse effects at 1 year of follow-up with a BNI score of 3. The systemic review identified 21 case reports with a combined cohort of 25 patients with TN secondary to stroke. Only 3 patients were treated with SRS, 2 of whom reported symptom improvement at 6 months and 8 months of follow-up with no adverse events.

CONCLUSIONS

Our case and literature review demonstrate durable and effective treatment with SRS, which can be considered a safe and effective treatment option for patients with stroke-associated TN.

Pain Mimicking Trigeminal Neuralgia in Patients with Acute Ischemic Stroke of the Brainstem

BACKGROUND AND PURPOSE

Cases of pain mimicking trigeminal neuralgia (TN) induced by ischemic stroke in the brainstem have been sparsely reported. The study was to determine the characteristics of symptomatic TN in patients with acute ischemic stroke in the medulla oblongata and pons, and to determine the location of the ischemic lesion associated with the pain.

PATIENTS AND METHODS

A total of 6/21 (28.5%) patients with medullary ischemic stroke and 3/34 (8.8%) patients with pontine ischemic stroke who experienced pain mimicking TN between 1 week before and 2 weeks after the stroke onset were enrolled in the study. All patients accepted neuroimaging examinations to determine the location of the ischemic lesion and the etiology of ischemic stroke. The characteristics of pain were recorded and analyzed.

RESULTS

Ischemic lesions of patients who experienced pain mimicking TN were located in the lateral medulla oblongata (n=6), nerve root entry zoo (n=2), and areas involved with the spinal trigeminal tract (n=1) in the pons. Half of the instances of pain induced by medullary ischemic stroke occurred prior to the stroke onset. The branch of V1 was exclusively involved in patients with lateral medullary infarction and the branches of V2 and V3 were typically involved in patients with pontine infarction. The pain was relieved spontaneously (n=4, 44.4%) or was controlled with drugs for neuropathic pain treatment (n=5, 55.5%).

CONCLUSION

Half of the instances of pain induced by medullary ischemic stroke occurred prior to the stroke onset. Pain mimicking TN might be a premonitory symptom of the medullary ischemic stroke. Pain mimicking TN induced by brainstem infarction has a good prognosis.