Shunt catheter disconnection has been well described in literature as a cause of shunt malfunction.
Disconnections in the system accounted for 41 (15%) of the malfunctions. The more distal the connection was from the ventricle, the higher the likelihood of disconnection. Furthermore, occipitally placed shunts had a significantly higher tendency to dislocate than frontally placed shunts. 1).
11% in the series of Stone et al. 2).
High tension is sometimes caused in the shunt tube between the two anchor point viz., head and chest wall due to movement of the neck or growth and may induce such dislocation and disconnection of the shunt tube 3).
The use of an extended length peritoneal shunt catheter may prevent shunt disconnection 4).
A haircut that includes the use of clippers at the occipital region causes a rapid increase in the shearing strain at the shunt connector site that may further stretch the shunt and induce shunt disconnection. Nurses and physicians must address the need to prevent shunt dislodgement caused by haircuts with clippers in young, rapidly growing, male patients who require shunts. A two- or one-piece shunt may prevent this complication 5).
A 5-year-old boy with a right-sided ventriculoperitoneal shunt presented with a 3-month history of progressively enlarging subperiosteal fluid collection in the scalp, which started in the right parietal region and had spread and extended across the midline to occupy both parietal regions. There were no changes in symptoms or signs from those observed 3 months previously. A CT scan confirmed the collection of fluid under the scalp over both parietal regions. The peritoneal catheter was found to be disconnected from the distal end of the functioning valve, which drained cerebrospinal fluid into the subperiosteal space. Distention of the parietal subperiosteal space led to stretching and tearing of the emissary veins. This resulted in the formation of a hydrohematocele. The spread of fluid to the opposite parietal region may be due to a disorganized and loose attachment of the periosteum to the widely separated sagittal suture 6).
Mechanical problems can be caused by disconnection of the parts of the shunt system, breakage of the tubing, and obstructions at either end of the tubing (especially glialependymal tissue in the brain)
Shunt disconnection has not been always represented a shunt malfunction. Many patients with disconnected shunt may be independent from shunt system, and it can be a good chance for patient to remove the shunt system 7).
Distal catheter disconnection or break with increasingly sophisticated shunts 8).
Are prone to disconnection. Continued vigilance and specific imaging are important. Catheter removal after disconnection may be difficult. Elective removal prior to disconnection in asymptomatic children has not been performed 9).
It has been determined from nine reports of disconnected catheters requiring revision surgery, that the listed ventricular catheters may become detached from the snap base assembly after implantation and that this condition may increase the need for emergency revision surgery. There have been no reports of patient death or permanent serious injury as a result of this issue.
Consequences for a patient with failure of a ventricular catheter may include: nausea, vomiting, headache, lethargy, change in mental status, seizures, visual disturbance, and other more serious conditions. Patients with questions are encouraged to talk with their physician or contact Medtronic Neurosugery at 1-805-571-8400, Monday – Friday, 8 a.m. to 5 p.m. CDT. Physicians with medical questions related to this issue or Medtronic therapies should contact Medtronic at 1-800-328-0810, Monday – Friday, 8 a.m. to 5 p.m. CDT.
Any adverse reactions experienced with the use of this product, and/or quality problems can also be reported to the FDA’s MedWatch Program by phone at 1-800-FDA-1088, by Fax at 1-800-FDA-0178, by mail at MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, MD 20852-9787, or on the MedWatch website at www.fda.gov/medwatch.
Rughani et al., reviewed the CT scans of 10 patients with an intact and functioning snap-shunt system to characterize the normal appearance of the snap-shunt connection. On CT scans the distance between the radiopaque portion of the ventricular catheter and the radiopaque portion of the reservoir dome measures an average of 4.72 mm (range 4.6-4.9 mm, 95% CI 4.63-4.81 mm). In the authors' patient with a fractured ventricular catheter, this interval measured 7.8 mm, and in the patient with a disconnection it measured 7.7 mm. In comparison with the range of normal values, a radiolucent interval significantly greater than 4.9 mm should promptly raise concern for a disconnected or fractured shunt in this system. This measurement may prove particularly useful when serial imaging is not readily available 10).