Dysfunction of Holter Mini Elliptical valves caused by minor head trauma

Ventricular Shunts

Ventricular shunts are mechanical devices used in the treatment of hydrocephalus, by means of which cerebrospinal fluid (CSF) is diverted from the ventricles to other low-pressure body cavities. Over the last 50 years, mechanical shunting has become the cornerstone for the treatment of hydrocephalus with shunt valves evolving from simple differential valves to complex programmable valves. The chief complications of ventricular shunting include obstruction, infections, and overdrainage causing subdural hematomas and slit-ventricle syndrome. As the number of commercially available valve designs continues to grow, each new generation aims at reducing the likelihood of complications, especially those resulting from overdrainage. Several studies aimed at establishing the superiority of any valve design have been conducted. All have highlighted the advantages and shortcomings of most models without conclusively providing evidence for choosing one over another. As a result, choices still rest on individual and institutional preferences.

Rationale and methodology of the multicenter pediatric cerebrospinal fluid shunt design trial. Pediatric Hydrocephalus Treatment Evaluation Group

Cerebrospinal fluid shunt failure remains a common and at times overwhelming problem in pediatric patients with hydrocephalus. Two new shunt valve designs, the Orbis-Sigma (Cordis Corporation, Miami, Florida) and the Delta valve (PS Medical, Goletta, California), have flow/pressure characteristics dramatically different from those of standard differential pressure valves which have been used for over three decades. Both new designs reduce the siphoning effect in the upright position, and have been reported to reduce shunt failure rates in uncontrolled series, allegedly due to reduction in shunt overdrainage. Most mechanical shunt failure in the first 2 years after implantation is due to proximal shunt obstruction, overdrainage, and loculated ventricles. By reducing the incidence of slit ventricles associated with standard valves, both new designs could be envisioned as reducing the early mechanical complications. The improved results with both new valves could, however, also be to a large extent due to other confounding effects of shunt surgery, including patient selection, surgical technique, and specific configuration of the components of the shunt other than the valve. There are also theoretical reasons why these valve designs might be worse than their predecessors, including the narrow orifice and high resistance of the Orbis-Sigma, and the flexible membrane of the siphon control portion of the Delta valve, which may increase the ventricular pressure in the upright position or become blocked by encasing scar tissue. For this reason a randomized trial is required to determine efficacy, and a standard differential pressure valve is required as the control design. A significant reduction in early shunt failure would dramatically improve the morbidity and mortality of pediatric hydrocephalic patients, as well as providing substantial savings to the health care system. Failure to determine any difference would focus attention on other issues surrounding shunt surgery, such as patient characteristics or surgical technique.

Cerebrospinal fluid shunt valve fracture with separation: report of three cases

Three cases of shunt valve fracture with separation are reported. Fracture with separation of the shunt valve of a cerebrospinal fluid shunt is an infrequent occurrence. Because a portion of the shunt valve is radiolucent on a shunt survey radiograph, this problem is easily overlooked if it occurs. The diagnosis can be made by comparing old and new shunt survey radiographs and noting the increased distance between radiopaque portions of the shunt on the new x-ray films.