Focal Kyphotic Angle and Transverse Canal Area as the Predictors of Japanese Orthopaedic Association Score Improvement in Cervical Spondylotic Myelopathy Patient after Laminoplasty

Introduction: Cervical Spondylotic Myelopathy (CSM) is a degenerative condition of the cervical spine that can lead to progressive neurological dysfunction. Laminoplasty is a commonly used procedure to treat this condition; however, the predictive factors contributing to postoperative clinical improvement require further investigation. This study aims to evaluate the roles of Focal Kyphotic Angle (FKA), Transverse Canal Area (TCA), age, and symptom duration as predictors of clinical improvement in CSM patients following laminoplasty. Material and methods: Case-control study was conducted retrospectively from March to December 2024. Thirty-two CSM patients undergoing C3–C7 laminoplasty were categorized based on JOA scores (≥13 or <13). Age, symptom duration, focal kyphotic angle, and transverse canal area were analyzed using statistical methods, including chi-square tests. Results: The results showed that an FKA < 7° was a significant predictor of clinical improvement compared to an FKA ≥ 7° (p<0.001; OR=33.00). Additionally, a TCA >167.92 mm was also found to significantly increase the likelihood of clinical improvement compared to a TCA <167.92 mm (p<0.001; OR=25.00). Symptom duration of less than one year was significantly associated with clinical improvement (p=0.005; OR=0.063). However, age under 60 years and symptom duration of less than one year were not significant predictors of clinical improvement (p=0.47; OR=1.66) (p=0.44; OR=1.8). Further multivariate analysis indicated that FKA < 7° and TCA >167.92 mm were the most influential predictors of clinical improvement (JOA score ≥ 13) in CSM patients post-laminoplasty. ( p = 0,011 x2= 0,509, df=2, p=0.775; sensitivity 81%, specificity 82% AUC=0,867, 95% CI: 0,734 – 1,001) Conclusion: FKA < 7° and TCA >167.92 mm are important predictors of clinical improvement in CSM patients after laminoplasty. These findings may assist in optimizing surgical intervention planning. Keywords: Cervical Spondylotic Myelopathy, Clinical Outcome Predictors, Focal Kyphotic Angle, Laminoplasty, Symptom Duration, Transverse Canal Area