Idiopathic normal pressure hydrocephalus: survey on current diagnostic and therapeutic procedures in clinical practice in Germany

Objective: Cerebrospinal fluid (CSF) shunting has become the standard treatment for idiopathic normal pressure hydrocephalus (NPH). Nevertheless, there is still disagreement on diagnostic criteria for selecting patients for surgery and optimal shunt management. The primary aim of the present study was to provide an update on the status of best practice, the use of different diagnostic algorithms and therapeutic management of idiopathic NPH in an European country. METHODS : A standardized questionnaire with sections on the assessment of clinical symptoms and signs of NPH, diagnostic work-up, therapeutic decision making, and operative techniques was sent to 135 neurosurgical clinics in Germany that regularly perform shunt surgeries.

Results: Overall, responses were received from 114/135 (84.4%) clinics. Most responders considered gait disturbance to be the hallmark clinical sign of idiopathic NPH (96%). A lumbar tap test was utilized always/ mostly by 97 centers (86%). In 43% of the centers, 30-40 ml CSF were removed with the spinal tap test. Spinal dynamic CSF studies were used by 12 centers only occasionally, and only by 1 center always for diagnostic purposes. Ventriculo-peritoneal shunting was the most frequent type of CSF diversion (> 90%). Pressure-controlled valves were used by the majority of units (95%) Overall 102 centers (93%) always/mostly used adjustable valves, and antisiphon devices were used always/ mostly in 50% of units.

Conclusion: The present survey demonstrates that there has been a remarkable change of practice and opinions on the diagnosis and treatment of idiopathic NPH over the past two decades in Germany. Remarkably, variabilities in practice among different centers are less common than previously and recommendations according to scientific publications and guidelines have been implemented more readily.