Effect of zero-profile and self-locking intervertebral cage and plate-cage construct on maintenance of cervical curvature after anterior cervical surgery

Abstract

To compare differences in the maintenance of cervical curvature after anterior cervical surgery between zero-profile and self-locking intervertebral cage and plate-cage construct (PCC). A clinical data of 100 patients with single-segment cervical disc herniation who were treated with anterior cervical discectomy and fusion were retrospectively analyzed between January 2015 and January 2016. Among them, 50 patients were treated with the zero-profile and self-locking intervertebral cage (group A) and 50 patients with the PCC (group B). There was no significant difference between the two groups in age, gender, bone mineral density, disease duration, operative segment, and preoperative visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, C 2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height ( P>0.05). The operation time and intraoperative blood loss were recorded. The postoperative VAS and JOA scores were used to evaluate the clinical efficacy. The C 2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height were measured on lateral X-ray films, and the interbody fusion was evaluated according to Pitzen's criteria. The operation time in group A was significantly shorter than that in group B ( t=2.442, P=0.021), but there was no significant difference in the intraoperative blood loss between the two groups ( t=0.812, P=0.403). All patients were followed up 24-36 months, with an average of 28.5 months. According to Pitzen's criteria for cervical interbody fusion, bone fusion achieved in both groups. The VAS score, JOA score, C 2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height of the two groups at 1 and 24 months after operation were significantly improved when compared with those before operation ( P<0.05). The C 2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height of group A at 24 months changed significantly compared with those at 1 month ( P<0.05). The other indexes of the two groups showed no significant difference between the different time points after operation ( P>0.05). There were significant differences in C 2-7 cervical curvature, segmental Cobb angle, and adjacent vertebral height between the two groups at 24 months after operation ( P<0.05); but there was no significant difference in the clinical indexes at 1 and 24 months and the imaging indexes at 1 month between the two groups ( P>0.05). Compared with the PCC, the zero-profile and self-locking intervertebral cage can significantly shorten the operation time and obtain the same clinical efficacy, but the intervertebral height loss and secondary cervical curvature change after operation is more serious.