Normal Pressure Hydrocephalus Surgery

Normal Pressure Hydrocephalus Surgery

The surgical procedure to implant a VP (ventricular peritoneal) shunt usually requires less than an hour in the operating room. After the patient is placed under general anesthesia, their scalp is shaved and the patient is scrubbed with an antiseptic from the scalp to the abdominal area. These steps are taken in order to reduce the chances of an infection. Incisions are then made on the head and in the abdomen to allow the neurosurgeon to pass the shunt's tubing through the fatty tissue just under the skin. A small hole is made in the skull, opening the membranes between the skull and brain to allow the ventricular end of the shunt to be passed through the brain and into the lateral ventricle. The abdominal (peritoneal) end is passed into the abdominal cavity through a small opening in the lining of the abdomen where the excess CSF will eventually be absorbed. The incisions are then closed and sterile bandages are applied.

After surgery

The patient generally stays under careful neurological observation for the first 24 hours following the procedure. Some neurosurgeons prefer to keep the patient flat in bed until nearly all the subdural air introduced during surgery dissipates. The bandages placed on the head and abdomen, covering the incision sites, are monitored for signs of infection. The patient will generally need to stay in the hospital from three to seven days. Follow-up visits will be necessary to check post-operative status and resolution of symptoms. Additional treatment, such as physical therapy, may be advised to help the patient attain previous levels of motor skills.

Possible complications

Although shunt surgery is a relatively simple neurosurgical procedure, the decision to undergo insertion of a shunt should not be taken lightly. The treatment of normal pressure hydrocephalus carries greater risks compared to the treatment of children with hydrocephalus, and therefore the operation should be undertaken only if the degree of disability or the progression of the disorder warrants.

The potential complications of shunt surgery should be viewed as those related to the actual operation, plus those that may occur days to years later. A complication can be thought of as any unwanted event related to the surgical procedure itself or the presence of the shunt. Potential complications may include the infection of the surgical wound or of the CSF (meningitis), bleeding into the brain or ventricles, or a seizure. A shunt infection may be indicated by fever, redness or swelling along the shunt track. Fortunately, these complications are uncommon and can be managed successfully in most cases.

Unlike may other operations in which the surgical risks are highest during the operation itself, most of the common and serious problems associated with shunting can occur weeks or even years after the surgery. The most common problem with shunt systems is that they can become obstructed (clogged). This can occur hours or years after the operation, sometimes multiple times. The likelihood of a shunt obstruction is thought to be about 50% for most patients. For patients with NPH, a shunt obstruction is usually discovered when the original symptoms recur. Fortunately, shunt obstructions in NPH are easily fixed and rarely result in serious problems.

The most serious complication that can occur following insertion of a shunt is a subdural hematoma (blood clot). Because most shunts drain CSF from the center of the brain (the ventricles), this may cause the surface of the brain to pull away from the skull, thus stretching and tearing blood vessels on the surface of the brain. The symptoms of a subdural hematoma vary from increasing headache to paralysis or even coma or death. Shunt-related subdural hematomas most commonly occur following a fall, even one involving only a minor bump to the head. Therefore, a patient with NPH should not hesitate to seek medical attention if abnormal symptoms d evelop. The risk of a subdural hematoma in a patient with NPH is approximately 10%. Given these potential complications, individuals need to assess their own situation to determine if the possible benefits of surgery outweigh the possible risks.

If the cause of NPH is known, success rates can be as high as 80 percent. In cases in which a cause is not known, the success rate varies from 25 to 74 percent.

Neurosurgeons do not agree on the factors that lead to a successful shunting procedure nor do they have similar success rates. The higher success rates, however, have been reported from medical centers using the more demanding diagnostic tests such as lumbar catheters or the measurement of CSF outflow resistance. It is important to note that if initial success is followed by a recurrence of symptoms, it may be due to a shunt or shunt failure, the need for shunt pressure re-programming (in the case of a programmable shunt) or simply a lower pressure shunt rather than failure of the procedure.

Rate of Improvement

The symptoms of gait disturbance, mild dementia and bladder control problems may improve within days of shunt surgery, or may take weeks to months to abate. However, there is no way to predict how fast, or to what extent, this improvement will occur. For patients who do improve, changes are seen in the first week in most cases. In addition, this improvement may range from mild to dramatic. It is also not possible to make general predictions of how long the improvement will last, as the course of clinical improvement varies for each patient. Some patients seem to reach a plateau, while others improve for months but then seem to decline again. Unfortunately, there are no guarantees.

Generally, patients with an implanted shunt system are not restricted in their daily activities, except those involving great physical exertion. Your doctor will discuss with you any restrictions that may be advisable. Most patients with hydrocephalus can look forward to a normal future. Shunts are expected to perform reliably over a long period of time. However, because hydrocephalus is an ongoing condition, patients do require long term follow-up care by a doctor. Having regular medical checkups at intervals recommended by the neurosurgeon is sensible.

Shunt Revisions

Occasionally, patients with shunt systems require revisions. A revision is a surgical procedure to modify, repair or replace a shunt system due to complications or changing patient conditions. In those cases where a change in shunt pressure is needed, a patient with a programmable shunt system will simply require their shunt to be externally (without surgery) re-programmed.

The patient or family of the patient must be responsible for follow-up care. Regular follow-up visits will help the neurosurgeon to identify any subtle changes that may be indicative of a shunt problem. Patients and family members should become familiar with the signs and symptoms of shunt malfunction as described below.

Some Symptoms of Shunt Malfunction

Headache
Vision Problems
Irritability
Tiredness
Personality Change
Loss of Coordination or Balance
Difficulty in Waking Up or Staying Awake
Return of Gait Disturbance
Mild Dementia
Incontinence