Influence of preoperative C7/T1 foraminal area on the efficacy of posterior cervical laminoplasty in the treatment of cervical spondylotic myelopathy

English Keywords:Cervical spondylotic myelopathy  C7/T1 foraminal area  Posterior cervical open-door laminoplasty  Axial symptoms

English Abstract:

  【Abstract】 Objectives: To investigate the effects on the efficacy of posterior cervical laminoplasty in patients with cervical spondylotic myelopathy of different C7/T1 foraminal areas before surgery. Methods: 76 patients who underwent posterior cervical open-door expansive laminoplasty for cervical spondylotic myelopathy in our hospital from September 2021 to September 2022 were analyzed retrospectively, including 58 males and 18 females, aged 64.4±8.5 years old. The area of C7/T1 foramina of patients was measured on the double oblique X-ray images before operation, and the patients were divided into two groups on the basis of the average C7/T1 foraminal area: Group A, C7/T1 foraminal area≤average value(40 patients), and group B, C7/T1 foraminal area>average value(36 patients). The operative time and intraoperative bleeding were collected and compared between groups, and the Japanese Orthopaedic Association(JOA) scores before surgery, 3 months after surgery, and 12 months after surgery were obtained to calculate the JOA score improvement rate; The axial symptoms at 12 months after surgery were recorded, and T test, analysis of variance, and chisquare test were used to analyze whether different preoperative C7/T1 forminal areas of patients affected the efficacies after posterior cervical laminoplasty. Results: The foraminal areas of C7/T1 was 35.2±9.7mm2 in group A and 65.7±13.1mm2 in group B, and C2-C7 Cobb angle before operation was 14.0°±3.6° in group A and 16.0°±5.5° in group B, with statistical differences respectively(P＜0.05). Group A was not significantly different from group B in terms of intraoperative bleeding(176.8±88.2mL vs 183.6±100.2mL) and operative time(127.5±23.6min vs 120.3±32.6min)(P>0.05). The JOA scores of group A and group B were 10.9±2.0 and 10.3±2.1 before operation, without statistical difference(P>0.05); The JOA scores of group A and group B were 12.8±1.5 and 14.0±2.2 at postoperative 3 months and 14.1±1.5 and 15.9±1.7 at 12 months after operation, with statistical differences respectively(P<0.05). There were statistical differences in the improvement rates of JOA scores between the two groups at postoperative 3 months and 12 months, respectively(P<0.05). The incidence of axial symptoms 12 months after operation in group A and group B was 42.5% and 19.4%, respectively, with statistical difference(P<0.05). Conclusions: Patients with larger C7/T1 foraminal area have better postoperative neurological recovery, higher rate of JOA improvement, and lower incidence of postoperative axial symptoms.