Microvascular Decompression for Oculomotor Nerve Palsy Due to Compression by Infundibular Dilatation of Posterior Communicating Artery

Microvascular Decompression for Oculomotor Nerve Palsy Due to Nonaneurysmal Neurovaslur Conflict: 5 Cases Report and Literature Review

BACKGROUND

Oculomotor nerve palsy (ONP) is frequently caused by aneurysm compression and diabetes mellitus. However, nonaneurysmal compression (nAVC) of the oculomotor nerve is a condition rarely reported in the literature. Cases treated with microvascular decompression (MVD) for nAVC-induced ONP (nAVC-ONP) are exceptionally rare.

METHODS

Between October 2022 and October 2023, we performed MVD surgery on 5 patients diagnosed with nAVC-ONP. The clinical symptoms, imaging characteristics, and intraoperative findings of these patients were reviewed and analyzed using a self-developed evaluation scale (S-T Evaluation Scale) to guide diagnosis and corresponding treatment plans.

RESULTS

All patients underwent MVDs and demonstrated favorable recovery and a good prognosis. No postoperative complications occurred in any of the patients. The superior cerebellar artery and posterior cerebral artery were common offending vessels in these cases.

CONCLUSIONS

Neurovascular conflict has been proposed as another possible cause of ONP in a limited number of cases. Based on our findings, MVD is a potentially effective solution for patients experiencing oculomotor nerve palsy resulting from nonaneurysmal neurovascular conflicts. It holds great promise for significantly alleviating symptoms and improving overall quality of life.

Microvascular decompression for a patient with oculomotor palsy caused by posterior cerebral artery compression: A case report and literature review

BACKGROUND

Aneurysm compression, diabetes, and traumatic brain injury are well-known causative factors of oculomotor nerve palsy (ONP), while cases of ONP induced by neurovascular conflicts have rarely been reported in the medical community. Here, we report a typical case of ONP caused by right posterior cerebral artery (PCA) compression to increase neurosurgeons’ awareness of the disease and reduce misdiagnosis and recurrence.

CASE SUMMARY

A 54-year-old man without a known medical history presented with right ONP for the past 5 years. The patient presented to the hospital with right ptosis, diplopia, anisocoria (rt 5 mm, lt 2.5 mm), loss of duction in all directions, abduction, and light impaired pupillary reflexes. Magnetic resonance angiography and computed tomography venography examinations showed no phlebangioma, aneurysm, or intracranial lesion. After conducting oral glucose tolerance and prostigmin tests, diabetes and myasthenia gravis were excluded. Cranial nerve magnetic resonance imaging showed that the right PCA loop was in direct contact with the cisternal segment of the right oculomotor nerve (ON). Microvascular decompression (MVD) of the culprit vessel from the ON through a right subtemporal craniotomy was carried out, and the ONP symptoms were significantly relieved after 3 mo.

CONCLUSION

Vascular compression of the ON is a rare pathogeny of ONP that may be refractory to drug therapy and ophthalmic strabismus surgery. MVD is an effective treatment for ONP induced by neurovascular compression.

Microvascular Decompression for Oculomotor Nerve Palsy due to Nonaneurysmal Vascular Compression

BACKGROUND

Diabetes mellitus and aneurysmal compression are well-known causes of oculomotor nerve palsy (ONP), but nonaneurysmal vascular compression of the oculomotor nerve has rarely been reported.

CASE DESCRIPTION

A 70-year-old nondiabetic man presented with left ONP for the past 2 days. Magnetic resonance imaging revealed the left posterior communicating artery to be compressing the left oculomotor nerve. Microvascular decompression of the offending artery from the nerve via a left frontotemporal craniotomy was performed; the nerve showed a color change suggestive of degenerative alteration. ONP was fully resolved within 1 month of surgery.

CONCLUSIONS

Whether nonaneurysmal vascular compression of the oculomotor nerve is a true cause of ONP is sometimes controversial. However, recent developments in magnetic resonance imaging can clearly demonstrate the spatial relationship between the oculomotor nerve and vessels. Detailed magnetic resonance imaging should be used to diagnose compression of the oculomotor nerve by blood vessels. Microvascular decompression is the treatment of choice in this situation.

The oculomotor neurovascular conflict: Literature review and proposal of management

BACKGROUND

The Oculomotor nerve (OCN) lies in a close relationship with large arteries inside the basal cisterns. Therefore, it may be compressed by vascular malformations or aneurysms. Nevertheless, the compression is not always related to pathologic conditions. Indeed, some cases of neurovascular conflicts of the OCN have been described in the literature.

METHODS

A case of neurovascular conflict of the OCN resolved after steroid treatment is reported. Additionally, a systematic literature review of those cases was performed.

RESULTS

OCN palsy due to a neurovascular conflict has been described as acute or chronic persistent palsy, or with an intermittent presentation. Symptoms result from compression, although asymptomatic compression is not uncommon. Surgical treatment, pharmacological treatment, and observation have been reported as options in the literature. Microvascular decompression was employed effectively in some cases of OCN neurovascular conflict. Nevertheless, other cases were treated successfully with steroids (persistent presentation) and carbamazepine (intermittent presentation). A management algorithm based on the results of the literature review is proposed.

CONCLUSIONS

Treatment options for OCN neurovascular conflicts and their results are heterogeneous. Based on the literature review, the pharmacological treatment seems to be the most appropriate first-line approach, reserving surgery for refractory cases. Collecting clinical information about new cases will allow defining treatment standards for this rare condition.