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Updated: Aug 3, 2026
Neuronavigation and Laparoscopy Guided Ventriculoperitoneal Shunt Insertion for the Treatment of Hydrocephalus
Published on: October 14, 2022
Risk Analysis Index as a preoperative frailty tool for elective ventriculoperitoneal shunt surgery for idiopathic
Evan Courville1,2, Kavelin Rumalla1,2, Syed Faraz Kazim1,2
11Department of Neurosurgery, University of New Mexico Hospital, Albuquerque; and.
Insights
Frailty assessment using the Risk Analysis Index (RAI) can predict adverse outcomes in older patients undergoing ventriculoperitoneal shunt (VPS) surgery for idiopathic normal pressure hydrocephalus (iNPH). Higher RAI scores correlate with increased complications, nonhome discharge, and mortality.
Area of Science:
- Neurosurgery
- Geriatric Medicine
- Health Services Research
Background:
- Idiopathic normal pressure hydrocephalus (iNPH) primarily affects elderly individuals, with ventriculoperitoneal shunt (VPS) surgery being the standard treatment.
- VPS surgery is associated with significant postoperative complications, posing risks for frail or high-risk patients.
- Preoperative risk stratification is crucial for optimizing surgical outcomes in this population.
Purpose of the Study:
- To investigate the utility of frailty scoring for predicting adverse events in iNPH patients undergoing elective VPS placement.
- To compare the predictive accuracy of the Risk Analysis Index (RAI) and the modified 5-item Frailty Index (mFI-5) for postoperative outcomes.
Main Methods:
- Analysis of the Nationwide Readmissions Database (NRD) from 2018-2019 for iNPH patients aged 60 years and older who underwent VPS surgery.
- Calculation of RAI and mFI-5 scores, with subsequent cross-tabulation to assess associations with overall complications, nonhome discharge (NHD), extended length of stay (eLOS), and mortality.
- Receiver operating characteristic (ROC) curve analysis to evaluate the discriminatory accuracy of RAI and mFI-5.
Main Results:
- A total of 9319 patients were included, with 7.4% readmissions, 6.4% perioperative complications, and 1.0% mortality.
- Increasing RAI scores demonstrated a significant association with higher rates of postoperative complications and adverse outcomes.
- The RAI showed statistically superior discriminatory accuracy compared to mFI-5 for predicting mortality, NHD, and eLOS, with C-statistics > 0.60 for 30-day mortality.
Conclusions:
- Elevated frailty, as measured by RAI, is linked to increased rates of nonhome discharge, 30-day mortality, unplanned readmissions, extended length of stay, and postoperative complications in iNPH patients.
- The RAI demonstrates greater predictive utility than mFI-5 for key adverse outcomes in this cohort.
- While RAI is valuable, consideration of potentially reversible clinical factors is essential to avoid overestimating risk and ensure accurate frailty assessment.
Objective:
Idiopathic normal pressure hydrocephalus (iNPH) predominantly occurs in older patients, and ventriculoperitoneal shunt (VPS) placement is the definitive surgical treatment. VPS surgery carries significant postoperative complication rates, which may tip the risk/benefit balance of this treatment option for frail, or higher-risk, patients. In this study, the authors investigated the use of frailty scoring for preoperative risk stratification for adverse event prediction in iNPH patients who underwent elective VPS placement.
Methods:
The Nationwide Readmissions Database (NRD) was queried from 2018 to 2019 for iNPH patients aged ≥ 60 years who underwent VPS surgery. Risk Analysis Index (RAI) and modified 5-item Frailty Index (mFI-5) scores were calculated and RAI cross-tabulation was used to analyze trends in frailty scores by the following binary outcome measures: overall complications, nonhome discharge (NHD), extended length of stay (eLOS) (> 75th percentile), and mortality. Area under the receiver operating characteristic curve analysis was performed to assess the discriminatory accuracy of RAI and mFI-5 for primary outcomes.
Results:
A total of 9319 iNPH patients underwent VPS surgery, and there were 685 readmissions (7.4%), 593 perioperative complications (6.4%), and 94 deaths (1.0%). Increasing RAI score was significantly associated with increasing rates of postoperative complications: RAI scores 11-15, 5.4% (n = 80); 16-20, 5.6% (n = 291); 21-25, 7.6% (n = 166); and ≥ 26, 11.6% (n = 56). The discriminatory accuracy of RAI was statistically superior (DeLong test, p < 0.05) to mFI-5 for the primary endpoints of mortality, NHD, and eLOS. All RAI C-statistics were > 0.60 for mortality within 30 days (C-statistic = 0.69, 95% CI 0.68-0.70).
Conclusions:
In a nationwide database analysis, increasing frailty, as measured by RAI, was associated with NHD, 30-day mortality, unplanned readmission, eLOS, and postoperative complications. Although the RAI outperformed the mFI-5, it is essential to account for the potentially reversible clinical issues related to the underlying disease process, as these factors may inflate frailty scores, assign undue risk, and diminish their utility. This knowledge may enhance provider understanding of the impact of frailty on postoperative outcomes for patients with iNPH, while highlighting the potential constraints associated with frailty assessment tools.
