Xiaoyu Yang, Ronald H. M. A. Bartels, Roland Donk, Mark P. Arts, Caroline M. W. Goedmakers, Carmen L. A. Vleggeert-Lankamp


November 2020, Volume 29, Issue 11, pp 2655 - 2664 Original Article Read Full Article 10.1007/s00586-019-06157-0

First Online: 12 October 2019

The association of cervical sagittal alignment with adjacent segment degeneration

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.

Graphic abstract

These slides can be retrieved under Electronic Supplementary Material.[graphic not available: see fulltext]


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