Hydrocephalus after gamma knife radiosurgery for schwannoma

Abstract

Objective: Gamma Knife radiosurgery (GKRS) has been established as an effective and safe treatment for intracranial Schwannoma. However, communicating hydrocephalus can occur after GKRS. The risk factors of this disorder are not yet fully understood. The objective of the study was to assess potential risk factors for hydrocephalus after GKRS. Methods: We retrospectively reviewed the medical radiosurgical records of 92 patients who underwent GKRS to treat intracranial Schwannoma and developed communicating hydrocephalus. The following parameters were analyzed as potential risk factors for hydrocephalus after GKRS: age, sex, target volume, irradiation dose, prior tumor resection, treatment technique, tumor enhancement pattern, and protein level of cerebrospinal fluid (CSF) after GKRS. Results: Of the 92 patients, eight of them developed communicating hydrocephalus. Target volume and tumor enhancement pattern, and protein level of CSF ware associated with the development of hydrocephalus. Conclusion: In particular, patients with intracranial Schwannomas with large tumor size, ring enhancement patterns, and high protein level of CSF should be carefully observed.

Hydrocephalus After Gamma Knife Radiosurgery for Vestibular Schwannoma: Favorable Outcomes After Shunt Placement

“…Patient 1 and Patient 2 had elevated CSF protein of 316.2 and 66.2, respectively. This is consistent with prior reports [ 3 ] and the hypothesis that protein blockage of arachnoid granulations is responsible for the development of hydrocephalus. The delay between onset of hydrocephalus and Gamma Knife radiosurgery in our patients, 20 and six months, respectively, is similar to prior reports and highlights the long window over which hydrocephalus can present.…”

“…More recently, studies have found that the period after Gamma Knife radiosurgery is a particularly high-risk time for the development of hydrocephalus. Previous studies have postulated that this is due to tumor necrosis, which causes CSF protein elevation and malabsorption at the level of the arachnoid granulations [ 2 - 3 ]. Indeed, Lee et al described a transient increase in tumor volume within three to four years after radiosurgery and argued that during this time tumor volume changed rapidly and the possibility of a protein level change in CSF leading to blockage of arachnoid granulations was high.…”

Single-fraction radiosurgery outcomes for large vestibular schwannomas in the upfront or post-surgical setting: a systematic review and International Stereotactic Radiosurgery Society (ISRS) Practice Guidelines

“…Hydrocephalus after radiosurgery may thus co-occur with a temporary tumor volume change after radiation and there is a crucial need for careful ongoing clinical and imaging follow-up [33]. Other authors suggested that large tumor size, ring enhancement patterns and high protein level of CSF should be carefully observed during follow-up course [34]. Thus, using programmable/adjustable MR-compatible ventriculo-peritoneal shunts in time might prevent devastating consequences due to increased intracranial pressure and a risk of sudden neurological decline.…”