Prevalence of hydrocephalus in 157 patients with vestibular schwannoma

Abstract

The purpose of this study was to determine the prevalence of hydrocephalus in patients with vestibular schwannoma. A second objective was to investigate possible etiologies for hydrocephalus in this population by attempting to correlate the incidence and severity of hydrocephalus with tumor volume and extent of fourth ventricular compression. The MRI examinations of 157 adult patients with vestibular schwannoma were retrospectively reviewed. Tumor size was quantified, and the presence of accompanying hydrocephalus was assessed, categorized as communicating type or non-communicating type and then rated as mild, moderate or severe (grades 1-3). Next, the degree of fourth ventricular distortion caused by tumor mass effect was evaluated and categorized as mild, moderate or severe (grades 1-3). Spearman's rank correlation coefficient was used to test the relationships between tumor volume and (1) the extent of fourth ventricular effacement and (2) severity of hydrocephalus. Hydrocephalus was present in 28/157 (18%) cases and was categorized as mild in 11/28 (39%), moderate in 15/28 (54%) and severe in 2/28 (7%). Communicating-type hydrocephalus was present in 17/28 (61%) and non-communicating type in 11/28 (39%). There was a positive correlation between the grade of non-communicating hydrocephalus and tumor volume (r=0.38; P<0.001) and between the severity of fourth ventricular compression and extent of hydrocephalus in this group(r=0.43; P<0.001). In patients who were classified as having communicating hydrocephalus, the correlation between tumor volume and the severity of hydrocephalus was poor (r=0.19; P=0.02) as was the correlation between the extent of fourth ventricular distortion and the severity of hydrocephalus (r=0.21; P<0.01). There is a high prevalence of hydrocephalus in patients with vestibular schwannoma. In a minority of cases non-communicating type hydrocephalus is present and the severity of hydrocephalus can be attributed to the affect of tumor volume on fourth ventricular compression. More commonly, however, communicating-type hydrocephalus exists and the correlation between the severity of fourth ventricular compression and extent of hydrocephalus is poor. Therefore, other etiologies for hydrocephalus, such as tumor protein sloughing, are likely relevant.

Hydrocephalus associated with vestibular schwannomas: management options and factors predicting the outcome

“…1,6,13,19,20,27,29 The communicating type of hydrocephalus is more frequent (61%-87.2%), and is caused by the sloughing of protein from the tumor secondary to increased vascular endothelial permeability, the development of meningeal adhesions, arachnoiditis, or seeding of tumor cells. 4,8,10,11,16 The decreased reserve capacity for CSF absorption due to aging might explain the higher rate of communicating hydrocephalus in elderly patients.…”

“…19 The type of hydrocephalus was assessed according to established radiological criteria: obstructive hydrocephalus was defined by a disproportionally small fourth ventricle in relation to the lateral and third ventricles, whereas communicating hydrocephalus was defined by a fourth ventricle exhibiting a proportionate degree of dilation in relation to the lateral and third ventricles. 20 The largest extrameatal diameter was used to determine tumor size. 15 The VSs were classified according to the Hannover tumor extension grading system, 23 facial nerve function was assessed according to the HouseBrackmann grading system, 14 and functional hearing was graded according to the new Hannover classification.…”

Gamma Knife Radiosurgery for the Vestibular Schwannomas, Technical Considerations and Hydrocephalus as a Complication

“…It has been proposed that protein molecules clog the pores of the semipermeable membrane that forms the barrier in the arachnoid granulations, thereby leading to impaired absorption of CSF. Among 157 patients who were reported by Rogg et al (Rogg, et al, 2005), 28 (18%) had a pre-existing hydrocephalus before receiving treatment; 39% of these patients had a non-communicating hydrocephalus, and 61% had a communicating type, and no significant association with tumour size was observed.…”

“…Hydrocephalus can occur at various stages during the natural course of a vestibular schwannoma (K. Park et al, 2009), and the reported incidence ranges from 3.7 to 15% of cases (Atlas, et al, 1996;Pirouzmand et al, 2001;Rogg et al, 2005). Occasionally, a large vestibular schwannoma can cause obstructive hydrocephalus, and CSF mal-absorption may be the cause of the communicating hydrocephalus (Gardner et al, 1954;Prasad, 2001;Rogg, et al, 2005).…”

“…Occasionally, a large vestibular schwannoma can cause obstructive hydrocephalus, and CSF mal-absorption may be the cause of the communicating hydrocephalus (Gardner et al, 1954;Prasad, 2001;Rogg, et al, 2005). It has been proposed that protein molecules clog the pores of the semipermeable membrane that forms the barrier in the arachnoid granulations, thereby leading to impaired absorption of CSF.…”