Validation and reliability of the Cervical Stiffness Disability Index in patients with atlantoaxial dislocation and its clinical application

English Keywords:Atlantoaxial dislocation  Atlantoaxial fusion  Occipitocervical fusion  Cervical mobility  Cervical stiffness

English Abstract:

  【Abstract】 Objectives: To develop a Chinese version of the Cervical Stiffness Disability Index(CSDI) scale, test its reliability and validity in evaluating cervical stiffness in patients with atlantoaxial dislocation, and to compare the clinical outcomes of posterior atlantoaxial fusion for atlantoaxial dislocation and occipitocervical fusion for combined C1 occipitalization or "sandwich fusion" atlantoaxial dislocation. Methods: The clinical data of 38 patients undergone posterior atlantoaxial or occipitocervical fusion for atlantoaxial dislocation at the Third Hospital of Hebei Medical University from June 2017 to June 2022 were retrospectively analyzed. There were 20 males and 18 females, aged 50.8±10.7 years old. The observation indexes included neck pain visual analogue scale(VAS) score, spinal cord function Japanese Orthopaedic Association(JOA) score, North American Spine Society(NASS) patient satisfaction scale, health questionnaire depression scale(PHQ-9), and CSDI score. The Chinese version of the CSDI was developed, and its internal consistency and test-retest reliability were assessed. Exploratory factor analysis was conducted to evaluate its construct validity. The patients were divided into two groups based on the satisfaction condition, as measured by the NASS scale, and Spearman correlation analysis was used to assess the relationships between postoperative satisfaction degree, CSDI score, and observational indexes. Outcome indicators such as CSDI score were analyzed through atlantoaxial dislocation subtype/procedure and satisfaction stratification comparisons. Results: The Chinese version of the CSDI demonstrated excellent reliability(Cronbach′s alpha=0.885, ICC=0.927). Exploratory factor analysis extracted two factors, explaining 66% of the total variance, indicating good construct validity of the scale. The CSDI Chinese version was moderately correlated with final follow-up cervical pain VAS score(r=0.509, P<0.01), JOA score(r=-0.42, P<0.01) and depression(r=0.549, P＜0.01). The increase in postoperative cervical stiffness was moderately correlated with satisfaction(r=0.493, P＜0.01). Patient satisfaction was influenced by JOA score and improvement rate at final follow-up, CSDI score, and depression. Axial symptoms(3.2±1.1 vs 2.1±1.4, P=0.021) and cervical functional limitations(38.4±15.4 vs 24.4±11.8, P=0.005) were worse after occipitocervical fusion than atlantoaxial fusion. Patients with high satisfaction reported better outcomes and lower CSDI score than those with low satisfaction(22.0±12.6 vs 35.7±12.7, P=0.002). Conclusions: The Chinese version of the CSDI scale has ideal reliability and validity in evaluating cervical stiffness in patients with atlantoaxial dislocation. Occipitocervical fusion is similar to atlantoaxial fusion in improving cervical spinal cord function, but its more significant postoperative axial symptoms and cervical spine functional limitations should not be ignored.