SYMPOSIUM: HYDROCEPHALUS. Shunt systems in the treatment of hydrocephalus
Wanda Mikołajczyk-Wieczorek, Emilia Nowosławska
The history of hydrocephalus treatment: The history of hydrocephalus operative treatment is very long, dating back to the times of Hippocrates (V century BC), who attempted to treat hydrocephalus by means of puncturing dilated cerebral ventricles. Along with general development of medicine, getting familiar with brain anatomy and physiology of cerebrospinal fluid circulation, and the development of new operational techniques in neurosurgery, a number of diverse hydrocephalus treatment methods had been introduced, but still it was a disease ending up with death or disability. A breakthrough moment, in which hydrocephalus treatment got revolutionized, was the day when a ventriculojugular shunt, with the use of a one-way flow stainless steel spring-ball valve, was first introduced in a six-month-old boy. Spitz and Nulsen reported this successful procedure in 1952. Since then, hydrocephalus treatment with the use of one-way shunt systems has become an approved and the most commonly used method of clinical management, which saves many patients’ lives, reduces their disabilities and lets them develop properly. The valve implantation made a huge progress in hydrocephalus treatment. However, shortly afterwards it turned out that these were imperfect systems leading to a variety of complications in patients. To date, in spite of a considerable progress in this field, a perfect valve has not been designed. Nowadays, the development of hydrocephalus surgical treatment takes two directions. The first is searching for an ideal valve, the other is improving neuroendoscopic techniques. Indications and contraindications for insertion of shunt systems: The valve implantation is indicated in the event of hydrocephalus diagnosis if: a) disease cause cannot be removed; b) there are no indications for endoscopic third ventriculostomy (ETV). Contraindications for the implantation of a valve are as follows: nervous system infections, bleeding to cerebral ventricles, severe systemic infections and skin infections. In order to reduce high intracranial pressure, a Rickham reservoir is initially implanted in infants or external ventricular drainage in older patients. Once cerebrospinal fluid is normalized and patient’s condition is stable, the valve can be implanted. Currently available shunts systems: Every shunt system is basically composed of three components: proximal catheter for access to cerebrospinal fluid (ventricular or lumbar), valve system, and distal catheter that diverts cerebrospinal fluid towards a drainage cavity (peritoneal or intracardiac). Most manufacturers offer a variety of shunt components and configurations. Available valve systems can be divided into four categories: 1) with respect to drain placement: a) ventriculoperitoneal shunt, b) ventriculoatrial shunt, c) lumboperitoneal shunt; 2) with respect to valvular mode of action: a) standard differential pressure valves, b) differential pressure valves with integral siphon-reducing devices, c) adjustable (programmable) valves, d) CSF flow-control valves; 3) with respect to valvular structure regulating flow: a) diaphragm valves, b) slit valves, c) miter valves, d) spring valves; 4) modifications and configurations of shunt system components. The choice of shunt systems: No unambiguous scientific criteria for the choice of the particular valve type exist. No such valve is obtainable, which could be better and effective than others. When one chooses a valve, he or she should make a precise clinical analysis of disease progression, focus on valve machinery and implantation method. Ventriculoperitoneal shunt insertion technique: Technically, it is a very easy procedure. However, it requires paying special attention because of possible numerous complications. The surgery should last as short as possible. Therefore, a sound knowledge of surgical techniques as well as shunt system construction and its working mechanism is required. Complications: Shunt complications can be categorized into three groups: 1) mechanical; 2) infectious; 3) functional failure. Postoperative care: Patient with valve transplant should be taken under neurosurgical, ophthalmological, and psychological care. We always try to inform our patients about symptoms of valve dysfunction. In order to determine if an implanted valve works well, we analyse patient’s clinical condition and ophthalmological, psychological, and imaging examination results.