Progressive cranial nerve palsy following shunt placement in an isolated fourth ventricle

Abstract

Cranial nerve palsy is rarely seen after shunt placement in an isolated fourth ventricle. In the few reports of this complication, neuropathies are thought to be caused by catheter injury to the brainstem nuclei either during the initial cannulations or after shrinkage of the fourth ventricle. The authors treated a child who suffered from delayed, progressive palsies of the sixth, seventh, 10th, and 12th cranial nerves several weeks after undergoing ventriculoperitoneal shunt placement in the fourth ventricle. Magnetic resonance imaging revealed the catheter tip to be placed well away from the ventricular floor but the brainstem had severely shifted backward, suggesting that the pathogenesis of the neuropathies was traction on the affected cranial nerves. The authors postulated that the siphoning effect of the shunt caused rapid collapse of the fourth ventricle and while the cerebellar hemispheres were tented back by adhesions to the dura, the brainstem became the only mobile component in response to the suction forces. Neurological recovery occurred after surgical opening of the closed fourth ventricle and lysis of the basal cistern adhesions, which restored moderate ventricular volume and released the brainstem to its normal position.

Cranio-cervical decompression and expansile duroplasty for isolated fourth ventricle in a patient with Chiari II malformation

“…10,12,24,25 The development of 6th and 7th cranial nerve palsies has been attributed to the catheter in the fourth ventricle; however, this appears unlikely. 12,24,25 The development of bulbar disturbance and tetraparesis is reminiscent of one pattern of presentation of Chiari I malformation. 26 Hydrocephalus is occasionally seen in Chari I and is relieved by decompression, which indicates that the obstruction is functional rather than due to scarring.…”

“…Pang et al described promising results in a patient similar to ours; his patient with isolated fourth ventricle and syringomyelia was initially treated with a fourth ventricular shunt. 12 This patient developed delayed progressive palsies of the 6th, 7th, 10th and 12th cranial nerves in the ensuing weeks. On MRI it appeared that the brain stem had shifted backward, possibly causing traction injury to the nerves.…”

Cranial Nerve Involvement as a Complication of Ventriculoperitoneal Shunt

“…Another case has been reported by Pang and coworkers. 7 They suggested that traction of the brain stem owing to continued CSF drainage may be the probable cause of multiple cranial nerves involvement. They treated their patient with release of arachnoid adhesions in the posterior fossa.…”

“…[1][2][3][4][5] Cranial nerves involvement is rare after shunt insertion in the fourth ventricle. 4,6,7 ''Direct stem injury'' at the time of operation, 6 ''touch'' of the surface of stem by catheter after decreased size of ventricle, 4 and ''traction'' of cranial nerves due to continuous cerebrospinal fluid (CSF) drainage 7 have been reported as the causes of this involvement.…”

Cranial nerve palsies after shunting of an isolated fourth ventricle

“…Most of the reports concern 6th and 7th nerve palsies, but 5th, 10th and 12th cranial nerve palsies have also been described 1 6 7 11–13. These complications, however, have been described mostly in children already having a VP shunt in the lateral ventricle since infancy.…”