Prognostic significance of C1–C2 facet malalignment after surgical decompression in adult Chiari malformation type I: a pilot study based on the Chicago Chiari Outcome Scale

Abstract

OBJECTIVEThe authors assessed the prognostic significance of various clinical and radiographic characteristics, including C1–C2 facet malalignment, in terms of surgical outcomes after foramen magnum decompression of adult Chiari malformation type I.METHODSThe electronic medical records of 273 symptomatic patients with Chiari malformation type I who were treated with foramen magnum decompression, C1 laminectomy, and duraplasty at Mayo Clinic were retrospectively reviewed. Preoperative and postoperative Neurological Scoring System scores were compared using the Friedman test. Bivariate analysis was conducted to identify the preoperative variables that correlated with the patient Chicago Chiari Outcome Scale (CCOS) scores. Multiple linear regression analysis was subsequently performed using the variables with p < 0.05 on the bivariate analysis to check for independent associations with the outcome measures. Statistical software SPSS version 25.0 was used for the data analysis. Significance was defined as p < 0.05 for all analyses.RESULTSFifty-two adult patients with preoperative clinical and radiological data and a minimum follow-up of 12 months were included. Motor deficits, syrinx, and C1–C2 facet malalignment were found to have significant negative associations with the CCOS score at the 1- to 3-month follow-up (p < 0.05), while at the 9- to 12-month follow-up only swallowing function and C1–C2 facet malalignment were significantly associated with the CCOS score (p < 0.05). Multivariate analysis showed that syrinx presence and C1–C2 facet malalignment were independently associated with the CCOS score at the 1- to 3-month follow-up. Swallowing function and C1–C2 facet malalignment were found to be independently associated with the CCOS score at the 9- to 12-month follow-up.CONCLUSIONSThe observed results in this pilot study suggest a significant negative correlation between C1–C2 facet malalignment and clinical outcomes evaluated by the CCOS score at 1–3 months and 9–12 months postoperatively. Prospective studies are needed to further validate the prognostic value of C1–C2 facet malalignment and the potential role of atlantoaxial fixation as part of the treatment.

A Clinical Study on the Treatment of Recurrent Chiari (Type I) Malformation with Syringomyelia Based on the Dynamics of Cerebrospinal Fluid

“…CCOS score evaluates the prognosis of patients with SM. Accordingly, patients were divided into the good prognosis and poor prognosis groups with 10 [ 29 ] as the cut-off point [ 29 ], including 12 with CCOS score > 10 and 3 with CCOS ≤ 10. No symptom deterioration was observed in postoperative patients.…”

Posterior fossa decompression and duraplasty with and without tonsillar resection for the treatment of adult Chiari malformation type I and syringomyelia

“…CCOS was then applied to the patients and the predictors of prognosis were analyzed in more detail using CCOS. [11]…”

Precise Management of Chiari Malformation with Type I

“…It is well known that description of symptoms is usually subjective due to the lack of a reliable and unified criteria, noticeable bias of clinical outcomes easily occurred in term of patient’s subjective complaint, especially whether operative intervention will virtually result in benefit should be analyzed by reliable quantitative measurable tools rather than qualitative methods such as symptom improvement or deterioration. Hence, Aliaga et al ( 26 ) firstly reported that a novel scoring system for assessing postoperative outcome of CM-I in 2012, which was proved that this scoring system is useful and reliable by quantitatively assessment according to the Chicago Chiari Outcome Scale (CCOS) ( 27 – 31 ). Another role model of a prognostic scoring system for outcome of patients with CM-I is the Chiari Severity Index (CSI) which was put forward by Greenberg et al ( 32 ).…”