Cross-sectional area of posterior extensor muscles of the cervical spine in asymptomatic subjects: a 10-year longitudinal magnetic resonance imaging study

Abstract

There has been no prospective study on agerelated changes of the extensor muscles of the cervical spine in healthy subjects. This study was conducted to elucidate any association between the changes in cross-sectional area of the extensor muscles of the cervical spine on MRIs and cervical disc degeneration or the development of clinical symptoms. Sixty-two subjects who underwent MR imaging by a 1.5-Tesla machine between 1993 and 1996 as asymptomatic volunteers in a previous study were recruited again 10 years later for this follow-up study. The mean interval between the studies was 11.0 ± 0.7 years. The cross-sectional areas of the multifidus, semispinalis cervicis, semispinalis capitis, and splenius capitis at C3-C4, C4-C5, and C5-C6 intervertebral levels were measured on T2-weighted axial images using Image J 1.42. The mean cross-sectional areas of the deep extensor muscles were 1,396.8 ± 337.6 mm 2 at the C3-C4 level, 1,514.7 ± 381.0 mm 2 at the C4-C5 level, and 1,542.8 ± 373.5 mm 2 at the C5-C6 level in the previous investigation. The cross-sectional areas were 1,498.7 ± 374.4 mm 2 at the C3-C4 level, 1,569.9 ± 390.9 mm 2 at the C4-C5 level, and 1,599.6 ± 364.3 mm 2 at the 10-year follow-up. An increase in the cross-sectional area of the muscles was more frequently observed in subjects in their tens to thirties in the initial study, while a decrease was more frequently observed in those in their forties and older in the initial study. Disc degeneration was not correlated with a change in extensor muscle volume. Development of shoulder stiffness during follow-up was significantly negatively correlated with a change in the cross-sectional area of the deep extensor muscles.

Changes in the cross-sectional area of deep posterior extensor muscles of the cervical spine after anterior decompression and fusion: 10-year follow-up study using MRI

“…This was repeated twice and the results were averaged. The intraobserver and interobserver reliabilities of the measurement were confirmed to be acceptable in the previous study [11]. Interval changes in the cross-sectional area were evaluated and compared between the two groups using paired and unpaired t tests.…”

“…In the previous study, which was conducted between 1993 and 1996, MRIs were also performed on 497 asymptomatic healthy volunteers who had no history of cervical trauma or surgery [5,8,10,11]. In the follow-up study 10 years later, 223 of these volunteers participated.…”

“…The cross-sectional areas of the multifidus, semispinalis cervicale, semispinalis captis, and splenius captis at the intervertebral levels C3/4, C4/5, and C5/6 were digitally measured on T2-weighted axial images using Image J 1.42, a Java-based version of the public domain NIH Image software. The measurement was conducted by manually tracing defined regions of interest within the fascial border of each muscle bilaterally, as previously described [11]. This was repeated twice and the results were averaged.…”

Inter-rater reliability of trunk muscle morphometric analysis

“…Furthermore, the experience of one of the assessors was not adequately described. In the cervical spine, extensor muscle CSA inter-rater reliability was also shown to be high between two assessors with an ICC of 0.84 (19), although in that study it was also not described whether these findings relate to combined muscles or individual muscle data or what the experience levels were of the assessors. Kilgour and colleagues (20) have more clearly defined inter-rater reliability between two assessors for some cervical spine muscle CSA individually (ICC of 0.92 for both obliquus capitis inferior and sternocleidomastoid muscles) and some muscles as a group (ICC 0.99 for combined trapezius, splenius and semispinalis muscles), based on T1 weighted MRI from 37 participants, although detail on assessor experience was also lacking.…”

“…As this is often lacking, the present study identifies inter-rater reliability of muscle volume and MFI for the left and right sides of several trunk muscles individually. In existing literature, frequently the inter-rater reliability of combined muscles, rather than individual muscles, has been reported (7,19,20 …”