Bilateral abducens and facial nerve palsies as a localizing sign due to reduction in intracranial pressure after fourth ventriculoperitoneal shunting

The entity of the trapped fourth ventricle: A review of its history, pathophysiology, and treatment options

An isolated or trapped fourth ventricle is a relatively rare, although serious, adverse effect of hemorrhagic, infectious, or inflammatory processes that involve the central nervous system. This entity usually occurs after successful shunting of the lateral ventricles and may become clinically evident with the development of delayed clinical deterioration. This decline of the neurological status of the patient is evident after an initial period of improvement of the relevant symptoms. Surgical treatment options include cerebrospinal fluid shunting procedures, along with open surgical and endoscopic approaches. Complications related to its management are common and are related with obstruction of the fourth ventricular catheter, along with cranial nerve or brainstem dysfunction. We used the keywords: "isolated fourth ventricle," and "trapped fourth ventricle," in PubMed^® and Web of Science^®. Treatment of the trapped fourth ventricle remains a surgical challenge, although the neurosurgical treatment armamentarium has broadened. However, prompt recognition of the clinical and neurological findings that accompany any individual patient, in conjunction with the relevant imaging findings, is mandatory to organize our treatment plan on an individual basis. The current experience suggests that any individual intervention plan should be mainly based on the underlying pathological substrate of hydrocephalus. This could help us to preserve the patient's life, on an emergent basis, as well as to ensure an uneventful neurological outcome, maintaining at least the preexisting level of neurological function.

Reversible Progressive Multiple Cranial Nerve Paresis in the Isolated Fourth Ventricle following Placement of Fourth Ventricle Shunt: Case Report and Review of the Literature

BACKGROUND/AIMS

Multiple lower cranial nerve paresis occurring after placement of a fourth ventricle shunt for an isolated fourth ventricle is an uncommon complication in the postoperative period. Of the various etiologies, direct brain stem injury by the catheter and rapid decompression of the fourth ventricle by the shunt causing traction on the cranial nerves have been reported in the literature.

METHODS

We report the case of a 9-year-old girl with an isolated fourth ventricle who developed bilateral facial and multiple lower cranial nerve paresis with bilateral internuclear ophthalmoplegia a month after placement of a ventriculoperitoneal shunt. The postprocedure MRI showed a well-decompressed fourth ventricle with catheter tip located along the long axis of the fourth ventricle.

RESULTS

She was managed non-operatively. She improved gradually in her cranial nerve paresis over the next 3 months and completely recovered at 9 months.

CONCLUSION

We believe the reversible multiple cranial nerve neuropathies resulted from acute decompression of the fourth ventricle following the shunt insertion. A gradual decompression of the dilated fourth ventricle by an aqueductal stent or a high-pressure shunting system could prevent this potential complication.