Neurosurgery for Hydrocephalus Treatment & Management
- Author: Herbert H Engelhard, III, MD, PhD, FACS; Chief Editor: Brian H Kopell, MD more...
Medical therapy is usually a temporizing measure. In transient conditions, such as sinus occlusion, meningitis, or neonatal intraventricular hemorrhage, medical therapy can be effective .
Acetazolamide (25 mg/kg/day in 3 doses): Careful monitoring of respiratory status and electrolytes is crucial. Treatment beyond 6 months is not recommended.
Furosemide (1 mg/kg/day in 3 doses): Again, electrolyte balance and fluid balance need to be monitored carefully.
Lumbar punctures: In neonates recovering from intraventricular hemorrhage, serial lumbar punctures can, in some cases, resolve hydrocephalus. If possible, this is the preferred method of treatment.
Removal of the underlying cause usually resolves hydrocephalus.
As performance of cerebrospinal fluid (CSF) diversion (most often ventriculoperitoneal shunting) has increased in frequency, so has awareness of the pitfalls of the procedure. Recently, a resurgence of interest in third ventriculostomies has occurred.[3, 4, 5]
Make every effort to identify the cause of hydrocephalus prior to considering a diversion procedure.
Do not consider an indwelling distal catheter in patients with active infection or high cerebrospinal fluid protein (>150 mg/dL).
Obtain some idea of brain compliance in order to select the optimum valve pressure and decide if the pressure-programmable valve should be used.
Use one dose of preoperative prophylactic antibiotics.
Reserve third ventriculostomy for obstructive cases in patients who have normal or near-normal spinal fluid absorptive capacity. Use a blunt instrument to penetrate the floor of the third ventricle. Sharp instruments or lasers can cause vascular injury. Leaving a clamped drain in place postoperatively might be prudent. The burr hole placed on the coronal suture allows a straight trajectory to the foramen of Monro. Stereotactic guidance is not needed if endoscopic techniques are used.
Ventriculoperitoneal shunting is by far the most common procedure for CSF diversion. The abdomen should be able to absorb the excess spinal fluid. Either 1 of 2 major locations for the burr holes are typically used. The ventricular catheter can be placed more reliably from the (right) frontal approach. Some surgeons still prefer parietooccipital catheters. The proximal catheter tip should lie anterior to the choroid plexus in the frontal horn of the lateral ventricle when the parietooccipital approach is used. Certain landmarks and measurements are used, as per neurosurgical texts. In difficult cases, stereotactic placement may be an option.
In a study of patients who underwent ventriculoperitoneal shunt surgery for idiopathic normal pressure hydrocephalus, cerebral perfusion was found to recover promptly in 62.5% of patients (10 of 16). Perfusion increased in the whole brain in 3 patients, in the right cerebral hemisphere in 1 patient, and in the separate cerebral regions (frontal, parietal, temporal, cerebellum, cingulate gyrus) in 6 patients. Perfusion improvement was predominantly observed in the frontal lobes: right frontal lobe in 3 cases and left frontal lobe in 3 cases.
In another study of patients who underwent ventriculoperitoneal shunt surgery for hydrocephalus, the overall shunt failure rate necessitating shunt revision was 46.3%, and the majority of shunt revisions occurred during the first 6 months after shunt placement. The shunt revision rate was significantly higher in pediatric patients (<17 yr) than in adult patients (>17 yr) (78.2% vs. 32.5%).
Ventriculoatrial shunting is usually the first choice for patients who are unable to have distal abdominal catheters (eg, multiple operations, recent abdominal sepsis, known malabsorptive peritoneal cavity, abdominal pseudocyst). The procedure carries more risk. Long-term complications are more serious (eg, renal failure, great vein thrombosis). Fluoroscopic guidance is necessary to prevent catheter thrombosis (short distal catheter) or cardiac arrhythmias (long distal catheter).
Reserve ventriculopleural shunting for patients with failed peritoneal and atrial shunts.
Torkildsen shunts or internal shunts are straight tubes that communicate to cerebrospinal fluid spaces without a valve. Their effectiveness and long-term efficacy are not proven.
Lumboperitoneal shunts are used in communicating hydrocephalus, especially if ventricles are small. Pseudotumor cerebri is the classical indication of this method of shunting. A positional valve is helpful because it turns off the flow of CSF when the patient is upright, thereby preventing overdrainage headache.
A recent meta-analysis suggested that endoscopic 3-dimensional ventriculostomy was more beneficial than a shunt procedure in patients with a noncommunicating hydrocephalus.
ICU observation after third ventriculostomy is advised.
In patients with high brain compliance, gradual assumption of the upright position and slow mobilization may reduce the incidence of early subdural hematoma formation.
Plain radiographs of the entire hardware system confirm good position and serve as excellent baseline studies for the future. Postoperative CT scan is used to document ventricular size (see Follow-up section).
Wounds should remain dry for at least 3 days postoperatively, until epithelialization has occurred.
In patients with pleural shunts, perform an early postoperative chest radiograph to ensure adequate absorption of fluid. Large effusions can occur in short periods, and respiratory problems can ensue.
If the patient has no clinical indicators of ventriculitis, CSF sampling from extraventricular drains should be performed once every 3 days, which reportedly decreases the incidence of ventriculitis.
Remove stitches by 2 weeks postsurgery.
Perform CT scan for baseline at 2-4 weeks postsurgery.
Monitor all children with shunts every 6-12 months. Carefully monitor head growth in infants. Check distal tubing length with plain radiographs when the child grows. Appropriate specialists should carefully assess child development.
What happens to ventricular size in patients who have a third ventriculostomy or Torkildsen shunt is not known. Other methods of assessment of patency need to be used, such as MRI flow studies and clinical evaluations (eg, detailed funduscopic examinations).
In patients with pseudotumor cerebri, visual acuity and fields should be monitored by the appropriate specialist.
The most common complications differ depending on the type of shunt and the underlying pathophysiology.
Infection is the most feared complication in the young age group. The overwhelming majority of infections occur within 6 months of the original procedure. Common infections are staphylococcal and propionibacterial. Early infections occur more frequently in neonates and are associated with more virulent bacteria such as Escherichia coli. Infected shunts need to be removed, the cerebrospinal fluid (CSF) needs to be sterilized, and a new shunt needs to be placed. Treatment of infected shunts with antibiotics alone is not recommended because bacteria can be suppressed for extended periods and resurface when antibiotics are stopped.
Subdural hematomas occur almost exclusively in adults and children with completed head growth. Incidence of subdural hematomas can be reduced by slow postoperative mobilization and perhaps by avoiding rapid intraoperative ventricular decompression. This allows for brain compliance reduction. The treatment is drainage and may require temporary occlusion of the shunt.
Shunt failure is mostly due to suboptimal proximal catheter placement. Occasionally, distal catheters fail. Suspect infection if the distal catheter is obstructed with debris. Abdominal pseudocysts are synonymous with low-grade shunt infection.
Overdrainage is more common in lumboperitoneal shunts and manifests with headaches in the upright position. In most cases, overdrainage is a self-limiting process. However, revision to a higher-pressure valve or a different shunt system occasionally may be necessary. A positional valve that closes when the patient is upright is also available.
Slit ventricle syndrome is an extremely rare condition in which brain compliance is unusually low. It mostly occurs in the setting of prior ventriculitis or shunt infection. The patient may develop high pressures without ventricular dilatation. The slit ventricle syndrome does not imply overdrainage, and the symptoms usually are those of high pressure rather than low pressure. Most experts also agree that slit ventricles predispose the patient to a higher incidence of ventricular catheter failure. Repeated ventricular blockage by the coapted ventricular wall may be helped by performing a subtemporal decompression that creates an artificial pressure reservoir and induces slight reenlargement of the slit ventricle.
Outcome and Prognosis
In general, outcome is good. A typical patient should return to baseline after shunting, unless prolonged elevated intracranial pressure or brain herniation has occurred. The neurologic function of children is optimized with shunting. Infection, especially if repeated, may affect cognitive status.
The best long-term results in the most carefully selected patients are no better than 60% in normal pressure hydrocephalus. Few complete recoveries occur. Often, gait and incontinence respond to shunting, but dementia responds less frequently.
Often, various other neurologic abnormalities associated with hydrocephalus are the limiting factor in patient recovery. Examples are migrational abnormalities and postinfectious hydrocephalus.
In a study of responders and nonresponders to shunt surgery for idiopathic normal pressure hydrocephalus, responders were found to have much higher preoperative pulsatile intracranial pressure than nonresponders.
Future and Controversies
Hydrocephalus research and treatment have advanced tremendously in the last 20 years. Examples are the development of new shunt materials and, more recently, programmable valve technology. Current research categories include the following:
Transplantation of tissue, such as vascularized omentum, to reestablish normal cerebrospinal fluid (CSF) could be the best method to treat communicating hydrocephalus.
Third ventriculostomies and aqueductoplasty eliminate the need for shunting in noncommunicating cases of hydrocephalus. New optics and smaller scopes have expanded this field over the last 5 years.
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