原著
前方除圧固定術における頚椎矢状バランスの変化の検討
2021 年 35 巻 1 号 p. 55-61
詳細
2021 年 35 巻 1 号 p. 55-61
Purpose : Preoperative parameters of cervical sagittal balance, including T1 slope (T1S) and C2-C7 sagittal vertical axis (cSVA), have been recognized as predictors of kyphosis and neck disability after cervical posterior decompression surgery. However, the importance of these parameters in anterior cervical discectomy and fusion (ACDF) has not been sufficiently studied. We investigated the temporal changes in these parameters, including C2-C7 cervical lordosis (CL), cSVA, T1S, and T1 slope minus cervical lordosis (T1S-CL), after ACDF and examined the influence of ACDF on cervical sagittal balance.
Materials and Methods : We retrospectively analyzed the clinical data of 24 patients (13 males ; 11 females ; mean age, 59.5±15.6) who underwent ACDF for up to 2 levels with a standalone polyether-ether-ketone (PEEK) cage. Patients with preoperative lordotic angles of 10° or more were allocated to the balance group, and those with angles less than 10° were allocated to the imbalance group. CL, cSVA, T1S, and T1S-CL were measured preoperatively and one year after surgery. The clinical outcomes were measured using the Japan Orthopedic Association (JOA) score, and the relationships between the JOA score and the cervical sagittal balance parameters were analyzed.
Results : After ACDF, a cervical lordotic angle of 3.8±4.6° was lost in the balance group (CL≧10°, n = 12), whereas a cervical lordotic angle of 5.1±8.6° was gained in the imbalance group (CL<10°, n = 12) ; a significant difference was observed between the two groups.
The analyses of all 24 cases revealed a weak correlation (r = 0.43) between the preoperative cSVA and the postoperative JOA score improvement rate at 1 year, but there were no relationships between the other parameters and the JOA score improvement rate. Moreover, a positive correlation (r = 0.66, p = 0.02) was observed between the preoperative cSVA and the JOA score improvement rate 1 year after surgery in the balance group.
Conclusion : The effect of ACDF on cervical sagittal balance depends on the preoperative lordotic angle. In a balanced lordosis case, preoperative cSVA correlates with the postoperative JOA score improvement rate, and preoperative cSVA may be predictive of the clinical outcomes.
