Background and Purpose- Pathological obstruction in arachnoid granulations after subarachnoid hemorrhage (SAH) can impede cerebrospinal fluid flow outward to the venous sinus and causing hydrocephalus. Because bone and arachnoid granulations share the same collagen type, we evaluated the possible relation between bone mineral density and shunt-dependent hydrocephalus after SAH. Methods- We measured Hounsfield units of the frontal skull on admission brain computed tomography in patients with SAH. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff Hounsfield unit in skull to predict osteopenia and osteoporosis in a large sample registry. According to the optimal cutoff skull Hounsfield unit values, study patients were then categorized as hypothetical normal, osteopenia, and osteoporosis. Odds ratios were estimated using logistic regression to determine whether the osteoporotic conditions are independent predictive factors for the development of shunt-dependent hydrocephalus after clipping for SAH. Results- A total of 447 patients (alive ≥14 days) with ruptured aneurysm SAH who underwent surgical clipping were retrospectively enrolled in this study during a 9-year period from 2 hospitals. We found that hypothetical osteoporosis was an independent predictor for shunt-dependent hydrocephalus after aneurysmal clipping for SAH after full adjustment for other predictive factors, including age (odds ratio, 2.08; 95% confidence interval, 1.06-4.08; P=0.032). Conclusions- Our study demonstrates a possible relation between possible osteoporosis and hydrocephalus after SAH. Hounsfield unit measurement on admission brain computed tomography may be helpful for predicting hydrocephalus during the clinical course of SAH in patients with osteoporosis or suspected osteoporosis.
Keywords: arachnoid; bone density; hemorrhage; hydrocephalus; osteoporosis.