Histological Osteoarthritic Changes in the Human Cervical Spine Facet Joints Related to Age and Sex

Lars Uhrenholt, PhD; Annie Vesterby Charles, DMSc; Markil Gregersen, DMSc; Jan Hartvigsen, PhD and Ellen-Margrethe Hauge, PhD

Disclosures

Spine. 2018;43(12):E689-E696. 

In This Article

Abstract and Introduction

Abstract

Study Design. Cross-sectional autopsy study.

Objective. Quantify histological changes in the lower cervical spine facet joints with regard to age and sex using systematic random sampling of entire joints.

Summary of Background Data. Neck pain is a common debilitating musculoskeletal condition and one of the highest ranked causes of years lived with disability. The cause of neck pain is multifactorial and osteoarthritis is one potential cause. The cervical spine facet joints have been implicated in the etiology of chronic neck pain. Hence, a detailed description of their anatomy and age- and sex-related changes is needed.

Methods. The lower four cervical spine segments (C4-C7 included) were obtained from 72 subjects during autopsy; 29 women (median age 53 years)[22–77] and 43 men (median age 38 years).[20–78] A total of 1132 articular facets were embedded in toto in hard plastic and sliced into 3-mm thick sections from where 10 μm thick histological sections were produced. Morphological variables were evaluated microscopically and histomorphometric variables were retrieved using random sampling methods. Data were analyzed with a linear regression model.

Results. Significant associations were found between increasing age and in particular splitting, fissures, osteophytes, thickness of the calcified cartilage, and subchondral bone plate. The thickness of the calcified cartilage and subchondral bone plate increased with increasing age, whereas the hyaline cartilage thickness decreased. Males had more extensive degenerative changes in the cartilage.

Conclusion. Using semiquantitative histological methods, degenerative findings were observed at all spinal levels involving the articular cartilage and the osseous structures of the cervical spine facet joints similar to those observed in larger weight-bearing joints. In particular, the thickening of the calcified cartilage and the subchondral bone identified the osteocartilaginous junction as an important area in osteoarthritis. These findings may be relevant for the pathogenesis of osteoarthritis.

Introduction

Neck pain affects people globally in vast numbers, carrying large healthcare expenditures and economic consequences for individuals and society.[1,2] The Global Burden of Disease 2010 Study found the global point prevalence of neck pain to be 4.9% (95% confidence interval [CI] 4.6–5.3).[2] Out of the 291 conditions studied in 2010, neck pain ranked 4th highest in contribution to years lived with disability.[2] In 2015, "lower back pain and neck pain" (i.e., combined) was the leading cause of disability globally according to the Global Burden of Disease Study 2015.[3] The prevalence of neck pain is higher in high-income countries (e.g., Northern America and Scandinavian countries) compared with lower-income countries and is generally higher in women.[2–4] The exact mechanism behind neck pain is unclear and the etiology appears to be multifactorial,[5] and influenced by social and psychologic factors.[6,7] Degeneration of spinal structures causing spondylosis and osteoarthritis (OA) may also contribute to neck pain, with the degenerative changes being particularly evident in the intervertebral disc and the cervical facet joints.[5,8–10] Hence, OA changes in the articular facets may explain some neck pain through known pain pathways,[5,9,11] although radiological studies of generalized cervical spine OA have found no significant association with neck pain.[12,13] The general histological appearance and function of the cervical spine facet joints is well known,[10,14] with the articular cartilage providing a surface area for load distribution and smooth mobility.[10] However, there is only limited data concerning the quantitative properties of the cartilage and subchondral bone.[15–18] The mean overall thickness of the articular cartilage is 0.4 mm in women and 0.5 mm in men based on a cryomicrotomal study.[19] In other joints the thickness of the calcified cartilage occupies approximately 5% (3%–8%) of the total cartilage thickness.[20–23] With increasing age the integrity of the articular cartilage deteriorates with superficial flaking (fibrillation), fissuring, erosions, denudation, and deformation.[24] In the calcified cartilage and subchondral bone remodeling takes place involving duplication of the tidemark, thickening of the calcified cartilage and subchondral bone as well as osteophyte formation and subchondral cyst formation.[10,20,22,25] Currently, a comprehensive understanding of age- and sex-related changes in the cervical spine facet joints is lacking. The etiology and progression of OA can be examined by means of histological methods and a recent study examined the cervical spine facet joint morphology and semiquantitative histomorphometry of 20- to 49-year-old people.[15] The current anatomical study adds to this knowledge by systematically quantifying the histological changes in the cervical spine facet joints of acutely dead people in the age range 20 to 79 years based on morphological and histomorphometric methods.

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