Hydrocephalus Surgery

The Shunt Operation

Ventriculoperitoneal Shunt Operation

Position of the child is important to correctly implant the shunt. The head is turned sharply to the left, and the placement is a right occipital placement. The burr hole is placed approximately 4 cm up from the inion and 3-4 cm off the midline. This occipital placement allows a relatively straight shot into the body of the ventricle so that the shunt catheter is mostly within the ventricle. This trajectory avoids the risk of going to low, through the internal capsule, which can happen with shunt placement sites that are more lateral and inferior.
An adequate length of ventricular catheter needs to be selected to place the tip anterior to the foramen of Munroe, where there is less choroid plexus, this is to lessen the risk of occlusion. Generally, a 6 cm catheter is used in a small newborn, an 8 cm catheter in an older infant and young child, and a 10 cm catheter in a child 18 months or older. Perioperative antibiotics can be used, though definitive data showing that this is mandatory is lacking.
The shoulderblades should be raised to elevate the chest and neck, and allow for a straight passage of the shunt passer with no secondary incisions between the head and the abdomen. The abdominal incision is a horizontal incision, either just below the ribcage or just lateral to the umbilicus. Once the shunt is laid in position, the dura is opened with a pinpoint cautery to have just a big enough opening to allow the passage of the catheter (a large dural opening can allow CSF to flow around the shunt and cause a subcutaneous fluid collection). The ventricle is tapped using a rigid brain cannula and once obtaining a good flow of CSF the ventricular catheter is fed into the ventricle through this tract without a stylette.
Fluid should then be aspirated from the lower end of the shunt to insure that the valve system is opened and then it is placed into the peritoneal cavity. A large amount of tubing can be placed in the peritoneal cavity, and up to the full length has been used without any problems to allow for growth. We will typically place 15-20" of peritoneal catheter in at the time of the initial shunt placements.

Ventriculoatrial shunting and Ventriculopleural shunting

For ventriculoatrial shunts, an incision is made across the anterior border of the sternomastoid muscle, and the jugular vein identified. Alternatly, the shunt can be into the common facial vein just as it enters the jugular vein. Once the jugular vein is isolated both proximally and distally with ligatures, the vein is tied off distally and a small opening made into the jugular vein to pass the shunt down the jugular vein into the right atrium of the heart.
The right atruim can be targeted easily using electrocardiographic (EKG) control this is done by attaching an alligator clip to the stylette of the distal tubing and connecting it to lead 2 of the anesthesia EKG machine. The atrium is indicated by the P wave configuration becoming more and more upright, and when it becomes a biphasic P-wave the tip has just entered the atrium (the optimal placement). A chest x-ray done in the recovery room should confirm that the catheter is at the correct location ( the T6 level). If a ventriculoatrial shunt is used, lengthening should be considered when the shunt tip rises above the T4 level, since above that distal malfunction is significantly more common.

Endoscopic surgery

Endoscopic surgery is abvantagous, compared to conventional craniotomy, as it causes much less trauma to the patient, so the recovery time after surgery is reduced. Endoscopic surgery, in some cases can be carried out with only local anesthesia. Operating endoscopically mans that only a small hole is drilled into the patieent's head, through which all the instruments as passed.
The endoscopic system's is made up of a number of parts. First there is a guide tube, this can be a flexibly or a rigid tube which is used to guide the tool to the correct position. A flexible tube has controls at the end so that it can be twisted to the correct possition. This guide tool will have a camera and a light so that the surgeon can see what the operation site on a monitor. Through the endoscopes tube a mnumber of differect tools ca be passed including forceps, scissors, probes, catherers, and lasers.

Risks of Surgery

Certain risks must be considered with any surgery. Although your surgeon will take every precaution to avoid complications, among the most common risks possible with shunt surgery are: infection, malfunction, disconnection, or obstruction. The sudden release of CSF during or after surgery can cause a subdural hematoma (blood clot) to form. Other possible risks include hemorrhage (excessive bleeding) within the brain. The most common problem encountered in patients with shunts is that the shunts can malfunction. Usually the problem is that the shunt catheter (either in the brain or the abdomen) becomes blocked with debris or tissue and the shunt can't properly drain. Rarely, the shunt valve becomes blocked or stops functioning. Shunt malfunctions occur in approximately 30-40% of children in the year after the shunt is inserted. By five years, approximately 60% of children will have had their shunts changed, and by 10 years, nearly 85% will have had at least one shunt revision.

Recovery

Some symptoms such as headaches may disappear immediately because of the release of excess pressure buildup. Generally, the patient may be allowed to be up and about, and a gradual return to normal activity will be encouraged. The length of the patient's hospital stay will be determined by his or her rate of recovery and availability of support at home.
By the time of your post-operative visit to the surgeon you may have noticed some further improvement and the incisions may be less sore. Your surgeon will remove skin sutures (stitches) that are not absorbable and will examine the incision; he or she may also evaluate neurological function.
If a neurological problem remains, rehabilitation may be necessary to maximize the patient's improvement. However, recovery may be limited by the extent of damage already caused by the hydrocephalus or associated condition and by the brain's limited ability to heal. If further surgery is needed to remove a brain tumor or correct a birth defect, this may be scheduled for a subsequent operation.
Follow-up tests may be required, including ultrasound, CT scanning, magnetic resonance imaging (MRI), or plain x-rays to ensure the shunt is working correctly. You and your family will be instructed to notify the neurosurgeon if problems occur. Don't hesitate to contact your hysician if any of the following symptoms occur:

Redness, tenderness, pain or swelling of the skin along the length of the tube or incision
Irritability or drowsiness
Nausea, vomiting, headache, or double vision
Fever
Abdominal pain.

If you are the patient, your surgeon will help determine when you can return to work and with what limitations. If a work release is necessary, it will be provided during a post-operative visit.
Driving a motor vehicle will be possible once your surgeon determines that you have recovered fully. Do not drive after taking narcotic pain medication.