Visual changes after space flight: is it really caused by increased intracranial tension? A systematic review.

INTRODUCTION: Spaceflight-Associated Neuro-ocular Syndrome (SANS) was linked to increased intracranial pressure (ICP) attributable to the combined effects of microgravity and environmental conditions encountered during spaceflight. Microgravity countermeasures as lower body negative pressure (LBNP) are potential interventions for SANS. Our aim is to provide a comprehensive qualitative analysis of literature contrasting simulation and spaceflight studies, focusing on the pathophysiology of SANS, and highlighting gaps in current knowledge. EVIDENCE ACQUISITION: We systematically searched PubMed electronic database for English primary research published until February 2019 discussing intracranial changes in spaceflight or simulated microgravity, excluding animal and experimental studies. Two authors screened all the abstracts with a third author resolving disagreements. The full-text manuscripts were analyzed in pilot-tested tables. EVIDENCE SYNTHESIS: Nineteen studies were reviewed; 13 simulation, and two out of six spaceflight studies were prospective. ICP changes were investigated in 11 simulation studies, where eight demonstrated a significant increase in ICP after variable periods of head-down tilt. three showed a significant increase in intraocular pressure (IOP) in conjunction with ICP elevation. With increasing ambient CO2: one showed an increase in IOP without further increase in ICP, while another showed a slight further decrease in ICP. LBNP demonstrated no significant effect on ICP in one and a decrease thereof in another study. After spaceflight, increased ICP on lumbar puncture was demonstrated in five studies. CONCLUSIONS: Exposure to microgravity increases ICP possibly precipitating ocular changes. Whether other factors come into play is the subject of investigation. Further randomized studies and methods of direct ICP measurement during spaceflight are needed.

Migration of the Distal Catheter of Ventriculoperitoneal Shunts in Pediatric Age Group: Case Series.

BACKGROUND: Ventriculoperitoneal (VP) shunting is the most commonly performed procedure in the treatment of hydrocephalus. VP shunt migration can occur at different sites. The aim of the study was to present different sites of abnormal distal shunt location, pathophysiology, and the management in each situation. METHODS: Between 2014 and 2017, all patients with hydrocephalus in the Department of Neurosurgery, Cairo University, were gathered prospectively. All pediatric patients below the age of 12 years with shunt migration of the distal end of the VP shunt were identified. RESULTS: Of 1092 patients operated on by the VP shunt between 2014 and 2017, 15 presented with shunt dysfunction because of distal shunt migration (6 anal, 3 scrotal, 1 colon, 1 peroral, 1 upper lumbar extrusion, 1 paraspinal, 1 penile, and 1 umbilical). Especially upper lumbar extrusion and paraspinal shunt location are extremely rare. All the 15 patients were treated successfully with VP shunts and prospectively followed until they presented with complications on different occasions. CONCLUSIONS: Peritoneal complications are among the most common causes of VP failure. We present a rare complication where the shunt migrates outside the peritoneal cavity elsewhere with ambiguous pathogenesis. Special considerations have to be appointed during the shunt revision surgeries of these cases.