**3. Clinical assessment**

In the second step we evaluate the patient's symptoms and spinal function. There is as yet no standard measure of disability in cervical deformity. It is important to

determine the patient's disability status with respect to concrete, everyday activities. Existing HRQL do not adequately capture CD disability and do not correlate with cervical malalignment. Therefore Stekas et al. [35] introduced the cervical deformity patient generated index (CD-PGI) that is designed to describe the most important limitations in health status for patients with cervical deformity.

Assessment of the patient's symptoms and complaints, as well as standing alignment, gait, and muscle weaknesses is essential. With progressive cervical malalignment, additional impairments can occur, including problems with horizontal gaze, coughing, swallowing and respiration. In addition, the patient is allowed to lie supine for at least five minutes in order to observe any passive correction of the neck deformity.

A full neurologic exam is needed. More severe deformity can lead to myelopathy and/or radiculopathy. Correlation between cervical kyphosis and severity of myelopathy is still under debate. Smith et al. [36] demonstrated correlation between cervical sagittal balance to myelopathy based on the Modified Japanese Orthopedic Association (mJOA) score. Additionally, we determine whether the patient is medically fit to undergo an extensive operation.

This raises the question of supine imaging which is considered the most realistic assessment of deformity as it does not require active extension. Unfortunately, the landmarks of the lower cervical spine used to assess lordosis are often obscured on plain radiographs. However, supine advanced imaging in the form of MRI or CT offers the simultaneous advantages of allowing for a truer assessment of lordosis, and clear visualization of landmarks in the lower cervical spine. It is recommended to request extensive supine sagittal imaging that includes the cervicothoracic junction and planned lower instrumented vertebra (LIV). Furthermore, these modalities are often obtained during routine workup of cervical deformity and therefore do not require any additional cost and radiation. The use of supine imaging before

*Planning Cervical Deformity Surgery Including DJK Prevention Strategies DOI: http://dx.doi.org/10.5772/intechopen.94390*

and during surgery has led to the development of new in-construct measurements, namely the C2-T1 sagittal angle (C2-T1 SA), C2-T4 sagittal angle (C2-T4 SA) and C2-T10 sagittal angle (C2-T10 SA) (**Figure 1**). These measurements have the advantage that they are independent of radiographic modality and patient position, as long as the fusion construct is stable. The **C2-T1 SA** is defined as the angle formed by a line from the centroid of C2 to the Centroid of T1, and a line parallel to the posterior body of T1. Similarly **C2-T4 SA** and **C2-T10 SA** are the angles formed by a line from the centroid of C2 to the Centroid of T4 and T10 respectively, and a line parallel to the posterior vertebral body of T4 and T10 respectively. Depending on the planned LIV, we further recommend adding one of these parameters to the other four main parameters, cSVA, T1S, C2S and TPA [28].
