gms | German Medical Science

Objective: The introduction of adjustable differential pressure (DP) and gravitational assisted (GA) valves has advanced the treatment of hydrocephalus within the last years. Due to the mobility of these chronic patients, treatment may be performed by various neurosurgeons at different centers. Since the documentation of valve settings is mandatory for decision-making, but a consistent nomenclature is still missing, we initiated a survey, how neurosurgeon document valve settings in various conditions.

Method: A questionnaire was sent to 55 German neurosurgical centers. It included 9 representative valve combinations (Medos, Codman; GAV, proGAV, proSA, Miethke-Aesculap) which could be named by multiple choice variations of valve adjustment descriptions or named individually as free text, The questionnaire was sent back by fax or email to the coordinating center.

Results: 33 (60%) returned eligible questionnaires were analyzed. Only 2 and 4 centers shared a corresponding documentation, respectively. In terms of resistant measurements 7 (21%) used cmH₂O, 1 (3%) preferred mmH₂O measure and 75% applied a combination of mm&cmH₂O according the described valve type. 27 (81%) document the actual setting of the DP and gravitational unit in proGAV separately, 6 (18%) used the effective shunt resistance as the sum of DP and GA unit, whereas only 3 (9%) define clearly what is meant. Selected unique version in brief: 2 centers sum the GA unit settings without adding the DP, 4 prefer to depict the settings in an compiled fraction-fashion, 5 (15%) constantly indicate the GAV likewise an denominator. 4 (12%) prefer to describe the settings clearly in detail using up to 116 characters. Interestingly, the two centers with separately polled pediatric neurosurgeons both significantly mismatch within their center.

Conclusions: The current survey for naming valve combinations and resistance settings reveals an inconsistent documentation. Especially a concise documentation appears to be misleading. This indicates that a reliable interinstitutional communication about this issue is handicapped. A consistent nomenclature may be needed and will presented as proposal.