- Shunt Blockage
- CSF Overdrainage
- The Slit Ventricle Syndrome
- Abdominal Complications
- Intra-abdominal Fluid Collections
- Shunt Infection
- The Presentation of Shunt Infection
- Organisms Responsible for Shunt Infection
- Treatment of Shunt Infection
- The Role of Antibiotic Prophylaxis in Shunt Surgery
Shunt obstruction is the commonest indication for shunt revision and, in the majority of cases, the cause is blockage of the ventricular catheter. Choroid plexus, brain tissue and cellular debris are frequently responsible for the occlusion. Obstruction of the shunt may, however, occur at any level in the shunt assembly. The risk of mechanical failure is related to the time from shunt surgery, with most of these complications occurring in the first post-operative year .
The clinical presentation is usually dominated by signs of raised ICP headache, vomiting and drowsiness are most common. In the infant population group, enlarging head circumference, tense fontanelle, CSF tracking along the course of the shunt and, rarely, seizures are additional indicators of underlying shunt malfunction. The time course of symptom onset is, however, extremely variable; in some, the onset may be insidious over days or weeks whilst in the more shunt-dependent individuals, rapidly progressive symptoms may develop in the space of a few hours.
It has been postulated that the site of insertion of the ventricular catheter has some bearing on the propensity for obstructive complications. The frontal site is preferred by some surgeons, who argue that placement in the frontal horn beyond the foramen of Monro reduces the likelihood of blockage by choroid plexus. This practice does suppose that accurate placement can be attained during blind shunt insertion and that choroid plexus is a major etiological factor in shunt obstructions. Malposition of the ventricular catheter is, however, well recognized and, furthermore, Sekhar has demonstrated that tissues other than choroid plexus, including glial tissue, leptomeninges, chronic inﬂammatory debris fibrin and thrombus may be responsible for catheter obstruction. In a prospective randomized trial, Bierbrauer et al.  failed to show any advantage of frontal placement over the occipital route.
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