Analysis of Cervical Motion During Flexion and Extension Cinematographic Recordings in Asymptomatic Elderly

INTRODUCTION AND RATIONALE Physiological motion of the cervical spine is a subject of interest for medical specialists. Although the term 'physiological motion' is commonly used, a proper definition has been lacking for a long time. Segmental range of motion (sROM, e.g. the amount of sagittal rotation in a segment between maximal flexion and maximal extension position of the entire cervical spine) is most commonly used to study motion. SROMs, however, suffer from large intra- and interindividual variability. Therefore, in the lower cervical spine, Boselie et al have recently described a consistent sequence of segmental contribution in sagittal rotation during flexion and extension in 20 healthy participants. This was based on historic reports. The mean age of the healthy participants was 23 years (SD 2.65, range 18-55 years). They showed that the sequence of segmental contributions in the lower cervical spine during the second half of extension of the entire cervical spine and head was uniform in 80-90% of the healthy participants. The sequence of segmental contributions was C4-C5 followed by C5-C6, and then C6-C7. Also, they described a group of single level cervical degenerative disc disease (CDDD) patients in which this sequence was present in only one patient (10%). This is the first method described which can reliably differentiate between normal or abnormal movement of the cervical spine in an individual subject. CDDD is degeneration of a cervical intervertebral disc and/or the adjoining vertebral bodies leading to cervical radiculopathy and/or myelopathy. CDDD occurs more often in elderly patients (> 50 years of age) and due to aging of the population this will become a larger problem in the future. Age has been shown to be associated with a 0.11 degree decrease of sROM per year, independent of degeneration. Given that there are five levels in the subaxial cervical spine, there is an associated five degrees decrease in motion of the total subaxial cervical spine for every 10 years of ageing. It remains unclear whether the normal sequence of segmental contributions in the lower cervical spine is also present in asymptomatic elderly. By confirming the normal sequence in this group, this can be used to determine abnormal motion in elderly patients suffering from CDDD. The intention is to use this in future research in patients with cervical myelopathy or radiculopathy undergoing surgery to compare the outcomes of different types of surgery (e.g. cervical arthroplasty or anterior cervical discectomy with fusion) and to compare the influence of the type of surgery on normal motion.

2. OBJECTIVES Primary Objective: To investigate whether the normal sequence of segmental contributions in the lower cervical spine during the second half of extension (C4-C5 followed by C5-C6, and then C6-C7), which is present in young asymptomatic controls, is similar in asymptomatic participants between 55 and 70 years of age by using cinematographic recordings.

Secondary objective: To determine sROM of C4-C5, C5-C6, and C6-C7 by analysing the flexion and extension cinematographic recordings in asymptomatic participants between 55 and 70 years of age.

3. STUDY DESIGN This is a fundamental research project in which asymptomatic elderly participants without neck pain or severe degenerative changes will be included. Participants will be recruited at Zuyd Hogeschool Sittard/Heerlen and Zuyderland Medical Center Sittard- Geleen/Heerlen by using posters notifying about the study. They can contact the researcher by email, who will inform them verbally and in writing. Informed consent will be signed if they meet the in- and exclusion criteria and if they are willing to participate. Flexion and extension of the cervical spine has been analysed through sagittal cinematographic recordings before. This was done in two groups with ten healthy participants in each group, from which an adequate analysis could be performed. Taking a possible loss to follow up of 10% into account, our study population will consist of 11 participants. No interim analysis will be performed. Each participant receives flexion and extension cinematographic recording twice to determine reproducibility and consistency of sequence between the two time points (T1 and T2). Recordings will be performed with an interval of two weeks, resulting in 22 cinematographic recordings. Inclusion is expected to take approximately three months. Possible participants have to complete the Neck Disability Index (NDI), participants scoring above 4/50 points will be excluded (which means they would be no longer be classified as 'no disability due to neck problems'). A lateral X-ray of the cervical spine will be made, which will be scored using Kellgrens' classification by two neurosurgeons to avoid inclusion of participants with severe degenerative changes. Participants with a Kellgren score (KS) of four will be excluded. A KS score of four indicates severe degenerative changes such as severe narrowing of the disc space, severe sclerosis of the vertebral plates, or multiple large osteophytes. Participants with KS between zero and three will be included, indicating no, minimal, or moderate degenerative changes.

4. STUDY POPULATION Population (base) Male and female participants between 55 and 70 years of age, without a history of neck complaints, an NDI score of 4 or less and a KS of 3 or less will be included. Participants will be recruited using posters in Zuyd Hogeschool Sittard/Heerlen and Zuyderland Medical Center Sittard- Geleen/Heerlen.