# Cervical sagittal alignment and its impact on degenerative cervical myelopathy outcomes

## TL;DR

Cervical spine alignment affects the progression and surgical outcomes of degenerative cervical myelopathy, with specific radiographic measures guiding treatment decisions.

## Contribution

This paper reviews the role of cervical sagittal alignment in DCM and introduces emerging global alignment measures like CTPA for surgical planning.

## Key findings

- Kyphotic alignment and increased SVA correlate with worse neurological outcomes in DCM patients.
- Anterior decompression is preferred for kyphotic spines, while posterior decompression suits lordotic or neutral spines.
- The C2–T1 Pelvic Angle (CTPA) is a novel measure to assess cervical alignment in the context of global spinal balance.

## Abstract

Degenerative cervical myelopathy (DCM) is a progressive spinal cord disorder driven by static compression and dynamic instability. Cervical sagittal alignment has recently emerged as a potential factor influencing both pathogenesis and surgical outcomes.

This review synthesizes current evidence on alignment parameters and their clinical relevance in DCM management, with the primary aim of guiding surgical decision-making.

A narrative literature review was performed, analyzing radiological parameters of cervical alignment, their normative thresholds, and associations with functional outcomes. Both cranio-cervical and subaxial metrics were examined, alongside emerging global alignment concepts.

Key parameters include C2–C7 sagittal vertical axis (SVA), cervical lordosis (CL), T1 slope (T1S), and the T1S–CL mismatch. Malalignment is generally defined as SVA >40 mm, CL < 15°, or T1S–CL > 20°. Increased SVA and cervical kyphosis correlate with reduced mJOA scores and poorer surgical results. Alignment also informs surgical strategy: anterior approaches are favored in kyphosis or ventral compression, while posterior techniques are preferred in lordotic or neutral spines. Novel measures such as the C2–T1 Pelvic Angle (CTPA) seek to contextualize cervical alignment within global sagittal balance. Evidence further suggests reciprocal cervical adaptations following thoracolumbar correction.

Cervical sagittal alignment is clinically relevant in DCM pathophysiology and surgical decision-making. While correlations between alignment parameters and outcomes are established, robust evidence defining corrective thresholds remains limited. Prospective studies are required to validate these measures and refine realignment strategies in DCM.

•Cervical sagittal alignment plays a significant role in the pathophysiology and surgical outcomes of degenerative cervical myelopathy (DCM).•Radiographic parameters such as C2–C7 sagittal vertical axis (SVA), cervical lordosis (CL), and T1 slope (T1S) are associated with functional outcomes and guide surgical planning.•Kyphotic alignment and increased SVA correlate with worse neurological status and reduced postoperative recovery in DCM patients.•Surgical approach should be tailored based on alignment, with anterior decompression favored in cases of kyphosis and posterior decompression appropriate in lordotic or neutral spines.•Emerging global alignment measures, like the C2–T1 pelvic angle (CTPA), aim to integrate cervical parameters into a holistic framework of spinal balance.

Cervical sagittal alignment plays a significant role in the pathophysiology and surgical outcomes of degenerative cervical myelopathy (DCM).

Radiographic parameters such as C2–C7 sagittal vertical axis (SVA), cervical lordosis (CL), and T1 slope (T1S) are associated with functional outcomes and guide surgical planning.

Kyphotic alignment and increased SVA correlate with worse neurological status and reduced postoperative recovery in DCM patients.

Surgical approach should be tailored based on alignment, with anterior decompression favored in cases of kyphosis and posterior decompression appropriate in lordotic or neutral spines.

Emerging global alignment measures, like the C2–T1 pelvic angle (CTPA), aim to integrate cervical parameters into a holistic framework of spinal balance.