Endoscopic Management of Intracranial Arachnoid Cysts

Summary

Large intracranial arachnoid cysts (ACs) are found to enlarge in the course of life. Inadequate communication between the cyst and the subarachnoid space is thought to be responsible for neurological symptomatology. An increasing number of patients present with space-occupying ACs but non-localizing or no symptoms at all. With standard neurosurgical techniques, i. e. microsurgical fenestration or shunting, clinical outcome and complication rate were unsatisfactory.

We evaluated 24 patients (seven female, 17 male) with intracranial ACs treated endoscopically between June 1993 and December 1996. Patient age ranged from 4 months to 65 years (mean 29 years), and follow-up time was 3 months to 2 years (mean 9 months). ACs were located in the anterior cranial fossa (two cases), in the temporal region (nine cases), suprasellar (six cases), and in the posterior cranial fossa (seven cases). Indications for surgery were hydrocephalus (eight cases), focal neurological deficit (three cases), obvious space-occupying character but non-localizing symptoms (11 cases), or no symptoms at all (two cases).

Surgical strategy was to create broad communication between the cyst and the subarachnoid space. Different techniques were used, i. e. endoscopic surgery (ES) in ten cases, endoscopic controlled microsurgery (ECM) in five cases, and endoscopic assisted microsurgery (EAM) in nine cases. In all 24 patients sufficient fenestration or partial resection of the cyst could be achieved. Favourable outcome was seen in 17 patients (71%), including the two asymptomatic patients, and six patients (25%) had unchanged symptomatology. One patient (4%), who is additionally operated on an astrocytoma of the quadrigeminal plate, deteriorated. Complications included infection in three patients (12%), bleeding into the cyst in one patient (4%), and subdural haematoma or hygroma in four patients (16%).

Our conclusions are: (a) different endoscopic techniques, i. e. ES, ECM and EAM do provide sufficient treatment of selected arachnoid cysts, (b) endoscopy makes looking and working “around the corner” possible and therefore enables inspection, fenestration or resection of cysts in different locations during the same minimally invasive approach, (c) patients with hydrocephalus or focal neurological deficits show the best results with improvement in 82%, and (d) the most frequent complications are infection and subdural hematoma.