Shunt-related cerebrospinal fluid overdrainage - a multicentre consensus definition.

BACKGROUND

Overdrainage of the cerebrospinal fluid (CSF) is a known complication of hydrocephalus shunt treatment. The concept of CSF overdrainage has evolved alongside advancements in shunt technology and hydrocephalus management. A systematic literature review identified 22 descriptions of CSF overdrainage, highlighting the lack of a universally accepted definition. To address this ambiguity, we conducted a multicentre consensus study to establish a clinically relevant definition of CSF overdrainage that can guide future research and clinical decision-making.

METHODS

A modified Delphi consensus process was conducted with 18 neurosurgeons and neuroscientists specialising in hydrocephalus from centres in Africa, Europe, India, and USA. Participants had at least ten years of clinical experience and/or significant publications in the field. The previous systematic literature review identified 32 clinical and radiological manifestations of CSF overdrainage, which were evaluated by the consensus-panel. The process included multiple rounds of structured questionnaires and virtual discussions. Consensus was achieved if a manifestation gained more than 70% support throughout the process. Finally, through iterative refinement the definitions were established.

RESULTS

The panel agreed that CSF overdrainage presents differently in various patient populations and should be defined by cardinal symptoms/findings rather than additional less frequent symptoms/findings. Three age-dependent definitions were established for paediatric patients: infants (age < 1 year), children with a growing skull (age 1 to 7 years), and children with a fixed skull (age > 7 years). A separate definition was formulated for adults (age ≥ 18 years). Across all age groups, CSF overdrainage was characterised by posture-related symptoms, primarily headache or in infants' irritability consistent with headache relieved in supine position. Radiological findings include ventricular collapse (age < 18 years) and non-traumatic subdural collections (all age groups).

CONCLUSION

Consensus-based definitions provide a standardised framework for future research and clinical management of hydrocephalus. It addresses the longstanding variability in diagnosis and treatment of CSF overdrainage in shunt-treated patients.