External validation of the Chicago Chiari Outcome Scale in adults with Chiari malformation type I

Abstract

OBJECTIVE The Chicago Chiari Outcome Scale (CCOS) serves as a standardized clinical outcome evaluation tool among patients with Chiari malformation type I (CM-I). While the reliability of this scale has been proven for pediatric patients, the literature lacks CCOS validation when used solely in adults. Therefore, this study aimed to determine the validity of the CCOS in an external cohort of adult patients. METHODS The authors retrospectively analyzed the medical records of symptomatic patients with CM-I who underwent posterior fossa decompression between 2010 and 2018 in six neurosurgical departments. Each patient was clinically assessed at the latest available follow-up. Gestalt outcome was determined as improved, unchanged, or worsened compared with the preoperative clinical state. Additionally, the CCOS score was calculated for each patient based on the detailed clinical data. To verify the ability of the CCOS to determine clinical improvement, the area under the receiver operating characteristic (AUROC) curve was evaluated. A logistic regression analysis using all four components of the CCOS (pain symptoms, nonpain symptoms, functionality, and complications) was performed to establish predictors of the improved outcome. RESULTS Seventy-five individuals with a mean age of 42 ± 15.32 years were included in the study. The mean follow-up duration was 52 ± 33.83 months. Considering gestalt outcome evaluation, 41 patients (54.7%) were classified as improved, 24 (32%) as unchanged, and 10 (13.3%) as worsened. All patients with a CCOS score of 14 or higher improved, while all those with a CCOS score of 8 or lower worsened. The AUROC was 0.986, suggesting almost perfect accuracy of the CCOS in delineating clinical improvement. A CCOS score of 13 showed high sensitivity (0.93) and specificity (0.97) for identifying patients with clinical improvement. Additionally, a meaningful correlation was found between higher CCOS scores in each component and better outcomes. Patient stratification by total CCOS score showed that those categorized as improved, unchanged, and worsened scored prevalently between 13 and 16 points, 10 and 12 points, and 4 and 9 points, respectively. CONCLUSIONS In this adult cohort, the CCOS was found to be almost perfectly accurate in reflecting postoperative clinical improvement. Moreover, all four CCOS components (pain symptoms, nonpain symptoms, functionality, and complications) significantly correlated with patient clinical outcomes.

Reoperation in Chiari-1 Malformations

“…The outcome of the 34 patients who required reoperation was evaluated, considering their initial status before any surgical treatment [15,16]. The QOL improved in twenty patients (58.8%), who scored 13-14 on the CCOS.…”

“…At the last follow-up, the clinical outcome of these patients was evaluated using the Chicago Chiari Outcome Scale [15]. Furthermore, the patient outcome was compared with the preoperative clinical state and was categorized as improved, unchanged, or worsened, based on the quality of life (QOL) [16].…”

“…= foramen magnum decompression + dural augmentation; FMD-WDA = foramen magnum decompression without dural augmentation; CSF = cerebrospinal fluid; PSMC = pseudomeningocele; OBDA = occipital bone decompression alone; EDS-FT = extradural section filum terminale; MRI = magnetic resonance imaging; ETC = endoscopic third ventriculostomy; VPS = ventriculoperitoneal shunting; SPS = syringoperitoneal shunting; C1 = atlas. * The number of patients is reported in bold; the numbers in parentheses represent the CCOS score for each patient[15,16].…”

“…Comparison between the outcomes of first-time and second-time surgeries. FMD = foramen magnum decompression; QOL = quality of life; CCOS = Chicago Chiari Outcome Scale[15,16].…”