Choroid plexus cyst development and growth following ventricular shunting

ManuscriptChoroid plexus cysts are typically incidental, asymptomatic cysts. They have been reported to hemorrhage and grow, causing symptoms of obstruction. However, growth and multiplication has not been reported following ventriculoperitoneal shunting procedures. A 66-year-old woman initially underwent a suboccipital retrosigmoid craniotomy for resection of a large petroclival meningioma. Preoperatively, the patient demonstrated imaging findings consistent with hydrocephalus. After surgery the patient required a ventriculoperitoneal shunt. Two years after the initial shunting procedure, imaging demonstrated significant growth of new bilateral choroid plexus cysts as compared with pre-shunt imaging. Post-shunt imaging also demonstrated evidence of diffuse dural enhancement characteristic of intracranial hypotension. Despite radiographic growth and multiplication of the cysts, the patient was clinically asymptomatic and had a good neurological outcome

Retained peritoneal shunt tubing causing hematuria

Journal ArticleThis 14-year-old boy with congenital hydrocephalus underwent initial shunt placement shortly after birth. During his first 6 years of life, multiple ventriculoperitoneal (VP) shunt revisions were performed to address seven shunt malfunctions and one shunt infection (Staphylococcus epidermidis). During the last shunt revision, which took place 8 years before the current presentation, it was noted that the distal peritoneal shunt tubing (Peritoneal Catheter, Standard, Barium Impregnated; Medtronic Inc., Minneapolis, MN) had fractured and was coiled in the pelvis. Nevertheless, the tubing was not retrieved at that time

Cluster evolution in steady-state two-phase flow in porous media

We report numerical studies of the cluster development of two-phase flow in a steady-state environment of porous media. This is done by including biperiodic boundary conditions in a two-dimensional flow simulator. Initial transients of wetting and non-wetting phases that evolve before steady-state has occurred, undergo a cross-over where every initial patterns are broken up. For flow dominated by capillary effects with capillary numbers in order of $10^{-5}$, we find that around a critical saturation of non-wetting fluid the non-wetting clusters of size $s$ have a power-law distribution $n_s \sim s^{-\tau}$ with the exponent $\tau = 1.92 \pm 0.04$ for large clusters. This is a lower value than the result for ordinary percolation. We also present scaling relation and time evolution of the structure and global pressure.Comment: 12 pages, 11 figures. Minor corrections. Accepted for publication in Phys. Rev.