A VENTRICULOSTOMY RESERVOIR

Two signs indicative of successful access in nuclear medicine cerebrospinal fluid diversionary shunt studies

BACKGROUND

Successful shunt access is the first step in a properly performed nuclear medicine cerebrospinal fluid (CSF) shunt study.

OBJECTIVE

To determine the significance of the radiotracer configuration at the injection site during initial nuclear medicine CSF shunt imaging and the lack of early systemic radiotracer activity as predictors of successful shunt access.

MATERIALS AND METHODS

With Institutional Review Board approval, three nuclear medicine physicians performed a retrospective review of all consecutive CSF shunt studies performed in children at our institution in 2015. Antecedent nuclear medicine CSF shunt studies in these patients were also assessed and included in the review. The appearance of the reservoir site immediately after radiotracer injection was classified as either figure-of-eight or round/ovoid configuration. The presence or absence of early systemic distribution of the tracer on the 5-min static images was noted and separately evaluated.

RESULTS

A total of 98 nuclear medicine ventriculoperitoneal CSF shunt studies were evaluated. Figure-of-eight configuration was identified in 87% of studies and, when present, had 93% sensitivity, 78% specificity, 92% accuracy, 98% positive predictive value (PPV) and 54% negative predictive value (NPV) as a predictor of successful shunt access. Early systemic activity was absent in 89 of 98 studies. Lack of early systemic distribution of the radiotracer had 98% sensitivity, 78% specificity, 96% accuracy, 98% PPV and 78% NPV as a predictor of successful shunt access. Figure-of-eight configuration in conjunction with the absence of early systemic tracer activity had 99% PPV for successful shunt access.

CONCLUSION

Figure-of-eight configuration at the injection site or lack of early systemic radiotracer activity had moderate specificity for successful shunt access. Specificity and PPV significantly improved when both signs were combined in assessment.

An improved reservoir for the flushing test to diagnose shunt insufficiency

OBJECTIVE Reservoirs integrated into hydrocephalus shunts are commonly used for the removal of CSF and for intra-ventricular pressure measurement. Pumping with the reservoir to diagnose shunt sufficiency is still a matter of controversy. The authors describe an improved flushing device and its characteristic features in vitro and in vivo. METHODS The flushing reservoir is constructed with a sapphire ball in a cage as a nonresistance valve to also enable the detection of distal occlusions. The most important reservoir parameters were investigated in vitro, simulating total and partial proximal and distal shunt occlusions. Then the expected advantages were assessed in vivo by evaluating the pump test data of 360 implanted reservoirs. The results were compared with those found in the literature. RESULTS The optimization of the technical parameters of the device, such as the high stroke volume in combination with moderate suction force, are obvious advantages compared with other flushing devices. Total occlusion of the ventricular catheter and the valve could be assessed with high certainty. The detection of a total obstruction of the peritoneal catheter or any partial obstruction is also possible, depending on its exact grade and location. CONCLUSIONS Shunt obstructions can be assessed using the pumping test. The reservoir construction presented here provides a clear enhancement of that diagnostic test.

Primary ventriculo-peritoneal shunts in treatment of hydrocephalus associated with myelomeningocele

In 50 children suffering from open myelomeningocele, a ventriculo-peritoneal shunt was employed as the primary procedure for control of hydrocephalus. In 11 cases the system was ultimately replaced by a ventriculo-atrial shunt, though this may not always have been necessary. In the remaining 39 patients satisfactory control of hydrocephalus was achieved. Obstruction, particularly of the peritoneal catheter, occurred frequently in the first 6 months but no revisions were required after 2 years. It is concluded that while ventriculo-peritoneal and ventriculo-atrial shunts achieve comparable success in controlling hydrocephalus, the former, due to the relatively innocuous complications, offers significant long-term advantages.

Complications from Holter ventriculo-atrial shunts

Three hundred and thirty cases of infantile hydrocephalus were treated at the Westminster Children's Hospital over a 6-year period with the Holter ventrculo-atrial shunt. The complications of the treatment are studied and methods of management discussed.

A technique for the insertion of Holter ventriculoatrial shunt for infantile hydrocephalus

A technique for the insertion of the Holter ventriculo-atrial shunt for the treatment of infantile hydrocephalus and the pre- and postoperative management of such patients is described.

The technique has been applied to 330 hydrocephalic children with minimal operative mortality and with a greatly reduced incidence of morbidity over previous methods. Simplification of the original method is considered an important factor in the satisfactory results.

The technique can be carried out in a general hospital without special equipment and by a surgeon with paediatric surgical experience but without special neurosurgical training.

Cerebrospinal fluid dynamics in the Arnold-Chiari malformation

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