Chronic adult hydrocephalus

Chronic adult hydrocephalus

Hydrocephalus is a disorder that consists of excessive accumulation of cerebrospinal fluid (CSF) inside the head. Under normal circumstances CSF develops in cavities that exist inside the brain called cerebral ventricles, and then goes through a series of ducts as pipes until it reaches the so-called subarachnoid spaces that surround the brain and spinal cord, where it will be reabsorbed to be flushed into the blood: Lateral ventricles >>> Third ventricle >>> Sylvian aqueduct >>> Fourth ventricle >>> Subarachnoid spaces.

When there is an imbalance between CSF formation and its reabsorption, hydrocephalus occurs. According to their mechanism of production, the following types could be considered:

1. Communicating hydrocephalus. CSF is properly formed and flows correctly from the ventricles to the subarachnoid spaces, but there is a disorder of resorption. This type requires the implantation of a CSF shunt from the cerebral ventricles to another body cavity where it can be reabsorbed. The most used is the ventriculoperitoneal shunt.

2. Non-Communicating Hydrocephalus. This type occurs when the CSF does not circulate through any point of its route due to an obstruction. For that reason they are treated creating an alternative route that allows the release of CSF from the ventricles saving the obstruction.

Hydrocephalus can occur at any age but symptoms are different in children and adults. In children it is mostly due to congenital malformation, and the most frequent symptoms are increased head size (in the smallest ones), growth retardation, headache, vomiting, excessive sleepiness and changes in the patient’s stare. It may appear abruptly or gradually in adults, and is usually manifested as headache accompanied by vomit, visual and eye alterations, and deterioration of the level of consciousness. The diagnosis is made by cranial CT or MRI scans, which allow identifying the fluid accumulation in the cerebral ventricles. In younger children it can be done by ultrasound done through the fontanelle.

Chronic Hydrocephalus of Adults or at normal pressure

It is a special type of hydrocephalus that appears in people of a certain age, clinically manifested as dementia (loss of memory and mental abilities), difficulty at walking (unsteady gait with small steps) and difficulty controlling urine. In these patients, in addition to the usual imaging tests, a lumbar puncture is also performed to extract a small amount of CSF and see the response. If symptoms improve after lumbar puncture, especially walking, we can expect a good response to surgical treatment, which involves the placement of a "valve". However, there is no evidence that guarantees 100% reliability that the patient will improve with the operation, so in some cases there may not be a good response to the treatment.

When is the surgical intervention indicated?

By operating the hydrocephalus the doctors intend to extract the excess of CSF accumulated inside the head. In general, bypass systems ("valves") are chosen. A "valve" is a system composed of several catheters (thin and flexible tubes) that carry fluid from the cerebral ventricles to another body cavity where it is reabsorbed (usually to the abdomen, but can also go to the heart or chest). "Valves" are permanent bypass systems.

When it is believed that hydrocephalus could be transient until the cause producing it is resolved (for example, a haemorrhage or a tumour), temporary bypass systems called "External Ventricular Drains" could be withdrawn when they are not needed.

What does the operation consist of?

The placement of a "valve" requires general anaesthesia. Through a small incision in the skin, a small hole (trephine) is made in the skull to introduce a first catheter, that is connected to a reservoir in which a valvular system regulates the amount of fluid that leaves the head. This reservoir is connected in turn with a second catheter, that will carry the extracted liquid towards the chosen cavity (peritoneum, pleura or heart) by tunnelling it under the skin so that it is usually not visible, leaving only a few small scars on the scalp, neck and abdomen.

What are the risks, complications and possible sequelae?

Hydrocephalus without treatment can be fatal, but its surgical treatment also involves certain risks. Sometimes infections in the "valve" occur, which require its withdrawal and antibiotic treatment, as well as a new intervention once the infection is resolved. It is also possible that it does not work properly (valvular malfunction), usually because they become blocked or ruptured, with symptoms reappearing and needing reoperation to check such "valve". Abdominal problems such as cyst formation, intestinal obstruction or even intestinal perforation may also appear. Though very infrequent, intracranial catheter placement may also produce serious complications such as cerebral haemorrhage or nerve injury, reversible or not.

Postoperative – Ventriculoperitoneal valve placement

After the intervention, the patient usually stays for a few hours in the post-anaesthetic recovery unit (PARU) or ICU depending on the preoperative clinical picture. The patient usually stays 48-72 hours in hospital during which a monitoring CT scan and a simple abdominal X-ray will be performed, receiving daily care in regard to the surgical wound, medication, postural changes, vital signs monitoring and commencement of rehabilitation if relevant. The suture is usually removed after approximately 7 days. By the second day the patient should be able to get up and start walking.

What happens at the hospital discharge?

This depends primarily on the patient's situation before surgery. If the patient has a good general condition and the radiological controls are adequate, discharge will be approved in the next few days; if not, it will be until he gains autonomy and can fend for himself. The suture or staples are removed a week after the intervention. Treatment after discharge will depend on personalised diagnosis, and will be planned by the neurosurgeon responsible for each patient.