Arachnoid cyst rupture producing subdural hygroma and intracranial hypertension: case reports

OBJECTIVE

To analyze the association between arachnoid cysts and subdural hygromas.

METHODS

We reviewed five cases of arachnoid cysts that ruptured, producing acute subdural hygromas. The surgical management and diagnostic methods used are assessed.

RESULTS

Five male patients ranging in age from 6 to 25 years sustained the rupture of arachnoid cysts, which produced acute subdural hygromas. Four of the patients had incurred blunt head trauma. All patients presented with symptoms referable to intracranial hypertension. The pathognomonic features of a middle fossa arachnoid cyst (MFAC) were noted on the computed tomographic scans and/or magnetic resonance images of each patient. The hygroma exerted mass effect on the ipsilateral hemisphere and was noted to be under significant pressure at the time of surgical intervention in each case. Two of the five cases are unique in the literature. In one, a coexisting quadrigeminal cyst ruptured, producing a subdural hygroma ipsilateral to the MFAC and dilating the basal cisterns. In the other, the MFAC ruptured into the basal cisterns as well as into the subdural space. The MFAC in each of the remaining three patients ruptured into the subdural space alone. All patients were treated with drainage of the subdural space. In the two patients in whom the basal cisterns were involved, both the hygromas and the MFACs failed to change significantly in size. The hygromas resolved completely and the MFACs decreased in size considerably in the three patients without cisternal involvement.

CONCLUSION

The rupture of an arachnoid cyst can produce a subdural hygroma and intracranial hypertension. The latter mandates emergent drainage of the subdural space. In patients in whom the basal cisterns are not dilated by cyst rupture, both the MFACs and hygromas resolve after subdural drainage.

[Endoscopic ventriculostomy in the treatment of obstructive forms of hydrocephalus]

Third ventriculostomy creating a pathway for the CSF from the third ventricle to the interpeduncular cistern is a rational and sound alternative to the implantation of the shunting system, including Torkildsen shunts in managing obstructive hydrocephalus. Twenty four patients with hydrocephalus aged from 6 to 46 (mean 21 year) were operated. In 20 patients the occlusion was caused by small tumors in the aqueduct area, in 4 cases the occlusion was due to non-neoplastic process. In the majority of cases (19 patients) third ventriculostomy was the first operation for hydrocephalus. A rigid ventriculoscope (K. Storz, Germany) with an external diameter of 6 mm was used in all procedures. In 23 patients a rapid clinical improvement was observed along with resolution of intracranial hypertension. Median follow-up of 7 months duration was possible in 18 cases. 16 patients remain stable with no signs of hydrocephalus. Control MRI studies showed patent ventriculostomy. 5 patients after an endoscopic procedure were treated with irradiation for tumors. In 2 patients the opening in the ventricular floor fused and became nonfunctional. It happened 4 months after fenestration followed by surgical removal of tumors of the pineal region which caused occlusion. Complications were observed in 2 cases. In one patient ventriculitis developed shortly after the procedure and resolved completely by the end of the second postoperative week. Another patient was noted to have signs of transitory moderate diabetes insipidus.

Consequences of cranial vault expansion surgery for craniosynostosis

Remodelling the cranial vault in an attempt to increase the intracranial volume and thus control intracranial hypertension, whilst at the same time improving the patient's appearance, has been the mainstay of surgery for syndromic craniosynostosis. We report a case of craniosynostosis in whom cranial vault expansion was followed by the development of hind-brain herniation and hydrocephalus. This prompted a review of our other cases of craniosynostosis who had been evaluated by magnetic resonance imaging following surgery in order to assess the frequency of hind-brain herniation and hydrocephalus in these children. Magnetic resonance imaging had been performed in the postoperative evaluation of 34 cases of craniosynostosis who had undergone procedures intended to increase the intracranial volume. The position of the cerebellar tonsils and the presence or otherwise of hydrocephalus was recorded for all cases. The effectiveness of surgery in treating raised intracranial pressure (ICP) was evaluated by means of postoperative ICP monitoring and had been performed in 22 cases. Herniation of the hind-brain below the level of the foramen magnum was observed in 18 cases (53%). Hydrocephalus, requiring the insertion of a ventriculoperitoneal shunt, was present in 14 cases (41%) and had developed after the cranial vault procedure in 9. The mean sleeping ICP measured postoperatively was normal (<10 mm Hg) in 5, borderline (10-15) in 7, and raised (>15 mm Hg) in 10 cases. Cranial vault expansion in complex craniosynostosis may fail to address the underlying aetiology of intracranial hypertension. Furthermore, both hydrocephalus and hind-brain herniation may develop following such surgery. Neither the increase in intracranial volume afforded by cranial vault expansion nor the shunting of hydrocephalus precludes the persistence of abnormal ICP. These findings are discussed in the light of possible mechanisms, in addition to cephalocranial disproportion responsible for intracranial hypertension in complex craniosynostosis. The implications for the surgical management of complex craniosynostosis are reviewed.

Jugular foraminal stenosis in Crouzon syndrome

We describe a 4-year-old boy with Crouzon syndrome, with associated acanthosis nigricans and Chiari-I malformation, who developed increased intracranial pressure necessitating posterior cranial expansion. Postoperatively, an arteriovenous fistula appeared over the mastoid region. Cerebral angiography demonstrated bilateral atresia of the jugular veins and occlusion of the left sigmoid and right transverse sinuses. We propose that increased intracranial venous pressure, secondary to bilateral jugular foraminal stenosis, caused hydrocephaly and venous dilation in the scalp vasculature. The latter set the stage for a traumatic arteriovenous fistula of the scalp, probably resulting from laceration of an adjacent artery and vein. Jugular atresia is a basilar malformation common to achondroplasia and certain eponymous syndromic craniosynostoses. Our patient has a mutation in fibroblast growth factor receptor 3, a different locus in the same gene mutated in achondroplasia.