# Etiology and Risk Factors for Shunt Revision in Adult Hydrocephalus: A Single-Center Retrospective Cohort Study

## TL;DR

This study examines why shunt revisions are needed in adult hydrocephalus patients, finding that infection is the most common cause.

## Contribution

The study provides insights into the etiology and risk factors for shunt revision in adult hydrocephalus patients.

## Key findings

- Infection is the most common reason for shunt revision, followed by obstruction and mechanical disconnection.
- Younger age is associated with a higher risk of shunt revision.
- The 12-month revision-free survival rate is 86.4%.

## Abstract

What are the main findings?
•This study highlights the necessity for revision in CSF shunting procedures.•Infection constitutes the most common reason for shunt revision.

This study highlights the necessity for revision in CSF shunting procedures.

Infection constitutes the most common reason for shunt revision.

What are the implications of the main findings?
•In our cohort, the revision-free survival was 86.4% at 12 months.•Patient age is associated with shunt failure and subsequent revision.

In our cohort, the revision-free survival was 86.4% at 12 months.

Patient age is associated with shunt failure and subsequent revision.

Background/Objectives: Hydrocephalus is defined as the symptomatic accumulation of excessive cerebrospinal fluid (CSF) within the ventricular system. It has an estimated incidence of 85 cases per 100,000 population annually in adults, making it one of the most common conditions managed by neurosurgeons globally. Many conditions may lead to ventricular dilation and hydrocephalus, such as hemorrhage, tumors, infection, trauma, and idiopathic normal-pressure hydrocephalus (iNPH). Regardless of the cause, the gold-standard treatment for hydrocephalus is CSF diversion, usually via a ventriculoperitoneal (VP) shunt. The goal of the present study is to present our experience regarding the etiology of hydrocephalus, management, and shunt failure characteristics over the last 11 years. Methods: A single-center retrospective cohort study was performed. Our cohort consisted of adult patients who were shunted or required revision surgery in our department over the last 11 years. Data regarding the etiology of hydrocephalus, management, shunt characteristics, revision status, and etiology of revision were collected and retrospectively analyzed. Univariable and multivariable logistic regression models were established in order to explore potential associations between the etiology of hydrocephalus and patient characteristics and risk of shunt revision. Revision-free survival probabilities were estimated using the Kaplan–Meier method, while shunt failure rates were also calculated. Results: Our cohort consisted of 114 patients, the median age was 59 (IQR = 26.5) years, and the male-to-female ratio was 1.04:1. The most common cause of hydrocephalus was iNPH (30.7%), followed by post-hemorrhagic (23.7%) and tumor-related hydrocephalus (21.1%). The 12-month revision rate was 13.6%, with overall revision-free survival of 86.4% at one year. Infection (43.2%) was the most common cause of shunt revision, followed by obstruction (16.2%), and mechanical disconnection and migration (18.9%). Younger age was associated with higher risk of revision, while etiology of hydrocephalus and patient sex were not. Conclusions: Our study adds to the pertinent literature data regarding hydrocephalus etiology, management strategies, and shunt failure rates across different hydrocephalus etiologies. Additionally, it serves as a foundation for future studies that could identify predictors of shunt failure, apart from the etiology of hydrocephalus, such as patient characteristics, surgical factors, or shunt types. Finally, we highlight the importance of comprehensive national and potentially continental registries, which will facilitate large-scale analyses.