Implantation of cerebral shunt and its positioning is fixed based on the kind and location of the fluid blockage suffered by hydrocephalus. The catheter that is placed in the cerebral ventricle is referred to as the proximal portion of the shunt which basically implies to its proximity to the brain. The right lateral ventricle is the most popular kind of shunt location chosen. The distal portion of the catheter is placed in the cardiac atrium via a chest cavity, bladder but mostly the route is made to end in the peritoneal space or the abdomen. The abdomen is usually considered as the least morbid of all locations. But in all cases, the distal end of the catheter can be positioned in any epithelial cell or tissues that can absorb the cerebrospinal fluid.
In infants, a subgaleal shunt is used which is a temporary measure since they can not tolerate any other kind of shunts. The surgeon makes a cavity in the subgaleal space and allows the CSF to flow out of the ventricles, which slowly reduces the strain. As the child develops the shunt will be turned into a potential shunt ventriculoperitoneal or VP.
Before surgery and general anesthesia, patients require adequate preoperative testing and informed consent. The patient should be positioned with the head centered spine so that the shunt reservoir sits at the tip. The pool is normally on the right side of the head and looks like a flat globe below the surface.
The surgeon reviews the shunt series imaging. Then the hair of the patient is parted with the help of a gel or can be completely shaved. The skin is cleansed with some antiseptic and then sterile fenestrated drape is applied over the reservoir site.
Now the surgeon inserts a very small 23 ga. butterfly needle which is kept perpendicular to the skin inside the reservoir. Some resistance can be felt when the needle enters. But then it is gradually progressed until a point is reached where the bevel of the needle is placed inside the reservoir, keeping the needle in a secured position so that the cerebrospinal fluid gradually enters the tubing.
The shunt is now tapped with the syringe and opening pressure is recorded with the help of a manometer. The surgeon now collects 5 ml of CSF into sterile specimen containers. The needle is then withdrawn from the reservoir and gentle pressure is applied over the entry site for 2 or 3 minutes. Gauze is applied to the site and the cerebrospinal fluid sample for glucose, protein, gram stain, cell count and culture is sent to the lab.
The whole surgery should not take more than an hour.