Shunt Overdrainage: Reappraisal of the Syndrome and Proposal for an Integrative Model

Although shunt overdrainage is a well-known complication in hydrocephalus management, the problem has been underestimated. Current literature suggests that the topic requires more examination. An insight into this condition is limited by a lack of universally agreed-upon diagnostic criteria, heterogeneity of published series, the multitude of different management options and misunderstanding of relationships among pathophysiological mechanisms involved. We carried out a review of the literature on clinical, radiological, intracranial pressure (ICP), pathophysiological and treatment concepts to finally propose an integrative model. Active prophylaxis and management are proposed according to this model based on determination of pathophysiological mechanisms and predisposing factors behind each individual case. As pathophysiology is progressively multifactorial, prevention of siphoning with gravitational valves or antisiphon devices is mandatory to avoid or minimize further complications. Shunt optimization or transferal and neuroendoscopy may be recommended when ventricular collapse and cerebrospinal fluid isolation appear. Cranial expansion may be useful in congenital or acquired craniocerebral disproportion and shunting the subarachnoid space in communicating venous hydrocephalus and idiopathic intracranial hypertension.

Management of Chiari malformation in syndromic and nonsyndromic craniosynostosis

OBJECTIVEAlthough the association between Chiari malformation (CM) and craniosynostosis is well recognized, management remains controversial. There are differences in the clinical course of CM in syndromic craniosynostosis (SC) patients and nonsyndromic craniosynostosis (NSC) patients. Still unclear is whether cranial expansion surgery, foramen magnum decompression (FMD), or both should be conducted and when the appropriate timing of surgery should be. Here, the authors retrospectively reviewed the clinical data at their institution to investigate the optimal management of CM associated with SC and NSC.METHODSThe authors retrospectively analyzed the clinical records of 163 children with craniosynostosis who underwent surgical treatment at the National Center for Child Health and Development between April 2002 and May 2018.RESULTSTwelve (10%) of 119 children with NSC and 14 (31.8%) of 44 children with SC were radiologically diagnosed with CM. The median age at which CM was radiologically diagnosed was 7 months. Of the 12 NSC patients with CM, 1 (8%) was symptomatic with gait disturbance. This patient underwent FMD following expansion surgery. Of the 14 SC patients with CM, 8 (57.1%) were symptomatic with central sleep apnea. For SC patients with symptomatic CM, cranial expansion surgery alone was conducted in 2 cases, FMD was conducted after cranial expansion in 4 cases, and FMD was conducted first and additional expansion surgery was then conducted in 2 cases. In all cases, symptoms of CM improved after completing this series of surgeries. Regarding patients with asymptomatic CM, cranial expansion surgery alone was performed, and none of the patients showed symptoms of CM thereafter in both SC and NSC cases.CONCLUSIONSMultiple surgeries tend to be necessary for symptomatic CM in both SC and NSC, while no patient with asymptomatic CM became symptomatic after cranial expansion surgery.