The association of cervical sagittal alignment with adjacent segment degeneration

Abstract

Purpose Cervical spine surgery may affect sagittal alignment parameters and induce accelerated degeneration of the cervical spine. Cervical sagittal alignment parameters of surgical patients will be correlated with radiological adjacent segment degeneration (ASD) and with clinical outcome parameters. Methods Patients were analysed from two randomized, double-blinded trials comparing anterior cervical discectomy with arthroplasty (ACDA), with intervertebral cage (ACDF) and without intervertebral cage (ACD). C2-C7 lordosis, T1 slope, C2-C7 sagittal vertical axis (SVA) and the occipito-cervical angle (OCI) were determined as cervical sagittal alignment parameters. Radiological ASD was scored by the combination of decrease in disc height and anterior osteophyte formation. Neck disability index (NDI), SF-36 PCS and MCS were evaluated as clinical outcomes. Results The cervical sagittal alignment parameters were comparable between the three treatment groups, both at baseline and at 2-year follow-up. Irrespective of surgical method, C2-C7 lordosis was found to increase from 11° to 13°, but the other parameters remained stable during follow-up. Only the OCI was demonstrated to be associated with the presence and positive progression of radiological ASD, both at baseline and at 2-year follow-up. NDI, SF-36 PCS and MCS were demonstrated not to be correlated with cervical sagittal alignment. Likewise, a correlation with the value or change of the OCI was absent. Conclusion OCI, an important factor to maintain horizontal gaze, was demonstrated to be associated with radiological ASD, suggesting that the occipito-cervical angle influences accelerated cervical degeneration. Since OCI did not change after surgery, degeneration of the cervical spine may be predicted by the value of OCI. NECK trial Dutch Trial Register Number NTR1289. PROCON trial Trial Register Number ISRCTN41681847.

Cervical sagittal alignment after Prestige LP cervical disc replacement: radiological results and clinical impacts from a single-center experience

“…In the current study, we did not find that these cervical sagittal parameters had any impact on the patientreported outcomes after CDR, which was consistent with the results reported by Yang et al [24] However, Guerin et al [25] reviewed the data of 40 Mobi-C CDR patients and found significant positive correlations between postoperative SA and the postoperative SF-36 score (r = 0.349, P = 0.027) and between the postoperative shell angle and postoperative VAS neck pain score (r = 0.422, P = 0.007). Shen et al [23] measured the T1s in 90 patients who underwent one-level Bryan CDR and found that a higher T1s was related to more obvious neck pain at the 6-year follow-up.…”

Association of cervical sagittal alignment with adjacent segment degeneration and heterotopic ossification following cervical disc replacement with Prestige-LP disc

“…Multiple studies have shown that there is a relationship between cervical sagittal balance and neck pain, cervical disc degeneration, and the outcomes of ACDF. 3,4,7,[9][10][11][12]21,26 However, the importance of cervical sagittal parameters in CDR is rarely noted. In addition, the cervical sagittal alignment and its impacts on clinical outcomes after Prestige-LP CDR has been rarely studied.…”

“…We measured cervical sagittal alignment parameters on the lateral radiographs according to the methods presented in previous studies (Figure 1). 21,22 The following parameters were evaluated: (1) CL, measured as the angle between the inferior end plate of C2 and the inferior end plate of C7; (2) FSUA, measured as the angle between the superior end plate of the superior vertebra and the inferior end plate of the inferior vertebra at the surgical segment; (3) sagittal cervical axis (SVA), measured as the distance between the plumb line from the center of C2 and the superior posterior corner of C7; and (4) T1s, measured as the angle between the superior end plate of T1 and a horizontal line. When obtaining radiographs, the anterior–posterior view of the cervical spine was taken at first, and patients were required to (1) stand and look straight ahead, with their hips and knees extended; (2) lean their back against the fluorescent screen.…”

“…If T1s cannot be obtained from lateral radiographs, then C7 slope would be measured, and T1s would be calculated using the following formula: T1s ¼ (C7 slope þ 0.54)/0.88. 21 The postoperative values (values at 1 week after surgery) of the cervical sagittal alignment parameters were measured. Because cervical sagittal alignment may change over time, the differences between the values at the last follow-up and postoperative values (last minus postoperative, D) were calculated.…”

A Comparison of 2 Anterior Hybrid Techniques for 3-Level Cervical Degenerative Disc Disease

“…ACDF has been shown to provide good alignment and TDR to improve cervical ROM [ 18 ]. However, few studies have shown that arthroplasty is superior in maintaining cervical alignment [ 19 ]. For example, TDR did not significantly improve sagittal profiles when compared with other cervical fusion techniques and is therefore not considered a lordosis-producing operation [ 20 ].…”