Shunt Over-drainage, Slit Ventricle Syndrome, Programmable Valves and Anti-Siphon Devices. A Narrative Review of a Multifactorial and Intractable Problem

Abstract

The current management strategy of hydrocephalus mainly involves the insertion of a ventriculoperitoneal shunt and is inherently related with a complication widely known as shunt over-drainage. Albeit this is a well-recognized complication, the true incidence and severity of this phenomenon remains undefined and most probably underdiagnosed, necessitating a more comprehensive pathophysiologic and therapeutic consideration. The slit ventricle syndrome is intimately related with the entity of shunt over-drainage, although who's the definition of the former is implicated by a lack of universally accepted inclusion criteria. Another point of controversy is related with the absence of widely accepted criteria that would be able to discriminate the existing differentiations between these two entities. This is reflected in the fact that there are many proposed, relevant, treatment protocols. The background for all this data is based on the uncertainty and ambiguity regarding the pathophysiological mechanisms that are implicated. Current efforts are centered on the implementation of precautionary measures, as well as on treatment of both of these entities. Currently, there are enough evidence that support the concept that prevention of siphoning via the use of gravitational valves or antisiphon devices is the most efficacious means contained in our current therapeutic armamentarium. We attempt to present an overview of this complex entity, emphasizing on the hydrodynamics of the cerebrospinal fluid circulation in conditions harboring a ventriculoperitoneal shunt, the effect of the siphoning effect and the role of programmable valves and anti-siphon devices in our effort to eliminate this phenomenon. Based on an extensive literature review and on expert opinion, we concluded that the insertion of an anti-siphon device (gravitational shunt valves) could reliably address the issue of over-drainage, when a patient assumes a vertical position. Besides that, there are ongoing prospective studies centered on the safety and efficacy of adjustable gravitational valves, whose results are of ultimate importance. It is of paramount importance to be recognized that, due to the complexity of the pathophysiology of shunted hydrocephalus, lifelong follow-up of patients with ventriculoperitoneal shunts is necessary.

Commentary: Extra-Axial Endoscopic Third Ventriculostomy for the Treatment of Slit Ventricle Syndrome: 2-Dimensional Operative Video

“…Innovations in shunt valve technology have promised benefits in reducing SVS, but outcomes data are mixed. The use of programable valves and antisiphoning devices may have a role in modifying the risk of SVS, 5 but these devices cost $3320 each, limiting their global application. 1 Patients with an extensive history of shunt failures, as rates of shunt failure in the first year are 40%, may benefit more from ETV or the MTV approach suggested by the authors.…”

“…1 Traditional approaches to SVS include endoscopic third ventriculostomy (ETV), change in shunt hardware, and even cranial vault expansion. [2][3][4][5] In this article, "Extra-Axial Third Ventriculostomy for the Treatment of Slit Ventricle Syndrome: 2-Dimensional Operative Video", 6 the authors describe an alternative approach to slit ventricle syndrome, using a minimal-access craniotomy for third ventriculostomy through fenestration of the lamina terminalis from a subfrontal approach. The authors demonstrate the efficacy of their approach in this small series (14 patients) with limited follow-up.…”

“…1 Patients with an extensive history of shunt failures, as rates of shunt failure in the first year are 40%, may benefit more from ETV or the MTV approach suggested by the authors. 5 The MTV approach has its challenges. MTV necessitates a craniotomy, which creates more tissue injury (though arguably less brain transgression) compared with an ETV.…”

“…1 Patients with an extensive history of shunt failures, as rates of shunt failure in the first year are 40%, may benefit more from ETV or the MTV approach suggested by the authors. 5…”

Cerebrospinal Fluid Dynamics Following Ventriculoperitoneal Shunt in Hydrocephalus: Do Technological Advancements Avoid Complications?

“…Panagopoulos D et al [24] conducted a narrative literature review focused on an analysis of shunt overdrainage and slit ventricle syndrome. The authors also reported technological advancements aimed in counteracting these treatment side effects.…”