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As a medical device, CSF shunts have a dismal record in relation to failure and infection, despite over 70 years of development. Although endoscopic third ventriculostomy and associated procedures may offer an alternative treatment in some cases, the majority of patients with hydrocephalus are still dependent on shunts. Indeed, for many patients a shunt is a life saving treatment. It is for this reason, and a lack of an alternative effective treatment, that we tolerate such high complication and revision rates. Despite being a necessity, the revision rate remains unacceptable and, akin to other medical devices, the importance of registries and databases is clear. Such tools allow studies such as the one by Farahmand and colleagues1 to be performed, and only through the collection of relevant data can the number of confounding factors be controlled (see page 1248).
In this issue, Farahmand and colleagues1 present a prospective study of 450 patients who have undergone shunt surgery. Within the 6 months after shunt placement, 85 (18.9%) underwent shunt revision. Children and patients with other conditions such as pseudotumour cerebri, who probably have some of the highest rates of shunt revision, were excluded. Of the numerous variables studied, including age, aetiology, previous infections or drains, skin conditions, use of the operating room prior to shunt surgery and surgeon’s experience, only the position of the ventricular catheter and the type of valve had a significant effect on revision rate.
A right frontal ventricular catheter, which was favoured by the authors, had the lowest rate of revision (11.6%). Right occipital ventricular catheters had a revision rate of 26.5% within the first 6 months which is higher than one would expect. Many surgeons use occipital catheters almost exclusively and would be surprised at such a high complication rate. A randomised study would clarify this issue further.
Adjustable or programmable valves have now been widely available for over a decade. Although they have clear theoretical benefits, especially in conditions such as idiopathic normal pressure hydrocephalus, demonstration of their practical benefits has not been as conspicuous as one would think.2 3 Farahmand and colleagues1 report that adjustable valves were less frequently (15.7% vs 22.4%) revised compared with non-adjustable valves in the first 6 months after insertion. However, adjustable valves were also more frequently associated with a right frontal ventricular catheter and therefore the contribution of adjustable valves to reducing the revision rate is not clear.
Attention to the problem of shunt failure and infection through the development and implementation of clinical protocols is likely to reduce these complications by ensuring awareness of important issues as well as compliance. During this prospective study for example, the authors state their revision rate fell from 21.1% to 9.1%.
Perhaps the most important theme of this paper is the imperative for improving treatment through refinement of existing shunt technology and the need for developing new treatments through improved understanding of CSF physiology in health and disease.
Competing interests None.
Provenance and Peer review Commissioned; not externally peer reviewed.
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