Relationship between cervical muscle morphology evaluated by MRI, cervical muscle strength and functional outcomes in patients with degenerative cervical myelopathy.

BACKGROUND: Cervical muscle alterations have been reported in patients with chronic neck pain, but the assessment of muscle morphology and strength has been overlooked in patients with degenerative cervical myelopathy (DCM). OBJECTIVES: This study aimed to investigate the relationship between cervical muscle degenerative changes observed on MRI, muscle strength and symptoms severity in patients diagnosed with DCM. DESIGN: Observational study. METHODS: Cervical muscle measurements of total cross-sectional area (CSA), functional CSA (fat free area, FCSA) and ratio of FCSA/CSA (e.g. fatty infiltration) were obtained from T2-weighted axial MR images from C2-C3 to C6-C7 in 20 patients. Muscle strength was assessed manually using a microFET2 dynamometer. The association between cervical muscle morphology parameters, muscle strength, symptoms severity and functional status was investigated. RESULTS: Greater mean CSA and FCSA was associated with greater overall muscle strength. The mean FCSA explained 37%, 76%, 39%, 20% and 65% of the total variance in flexion, extension, right-side bending, left-side bending and overall muscle strength, respectively. The mean ratio of FCSA/CSA was not significantly associated with cervical muscle strength in any direction. However, greater FCSA/CSA ratio (e.g. less fatty infiltration) was associated with lower disability score (p = 0.02, R2 = 0.20). CONCLUSIONS: Cervical muscle lean muscle mass was positively associated with cervical muscle strength in patients with DCM. Moreover, greater fatty infiltration in the cervical extensor muscles was associated with lower functional score. Such findings suggest that clinicians should pay greater attention to cervical muscle morphology and function in patients with DCM.

Quantitative Magnetic Resonance Imaging Analysis of the Cervical Spine Extensor Muscles: Intrarater and Interrater Reliability of a Novice and an Experienced Rater.

STUDY DESIGN: Reliability study. PURPOSE: To examine the reliability of novice and experienced raters for measurements of the size and composition of the cervical extensor muscles using a thresholding technique. OVERVIEW OF LITERATURE: Although some authors have reported on the dependability of magnetic resonance imaging (MRI) measurements of the cervical muscles, there remains some variability regarding intrarater and interrater reliabilities, and few studies have examined the associated measurement error. Whether the rater's experience noticeably influences the reliability and precision of such measurements has also not been examined. METHODS: A sample of 10 patients with cervical pathologies was selected. Muscle cross-sectional area (CSA), functional cross-sectional area (FCSA), and signal intensity of the cervical extensor muscles were acquired from axial T2-weighted MRIs by a novice and an experienced rater. All measurements were obtained twice, at least 5 days apart, while the raters were blinded to all earlier measurements. RESULTS: Interrater reliability estimates (intraclass correlation coefficients) varied between 0.84 and 0.99 for the novice rater and between 0.94 and 0.99 for the experienced rater, indicating excellent reliability. The standard error of measurement for the novice rater was, however, noticeably higher for all cervical muscle measurements. Most of the interrater estimates showed excellent agreement with the exception of CSA measurement of the semispinalis cervicis at C4-C7 and FCSA measurement of the multifidus and semispinalis cervicis at C4-C7, which showed poor interrater reliability. CONCLUSIONS: The proposed method of investigating cervical muscle measurements was highly reliable; however, novice raters should receive adequate training before using this method for diagnostic, research, and clinical purposes.

Association Between Paraspinal Muscle Morphology, Clinical Symptoms, and Functional Status in Patients With Degenerative Cervical Myelopathy.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: The aim of this study was to assess fatty infiltration and asymmetry of the multifidus (MF), semispinalis cervicis (SCer), semispinalis capitis (SCap), and splenius capitis (SPL) muscles in patients with degenerative cervical myelopathy (DCM), and evaluate their correlations with clinical symptoms and functional scores. SUMMARY OF BACKGROUND DATA: Cervical muscle alterations have been reported in patients with chronic neck pain, but the assessment of cervical muscle morphology has been overlooked in patients with DCM. METHODS: Thirty-eight patients diagnosed with DCM and spinal cord compression at C4-C5 or C5-C6 (first level of compression) were included. Cervical muscle measurements of cross-sectional area (CSA) and ratio of functional CSA (fat-free area, FCSA) to total CSA were obtained from T2-weighted axial images at the level above, same, and level below the most cranial level of spinal cord compression. Muscle fatty infiltration and asymmetry was assessed at every level and their associations with respect to clinical signs and symptoms and functional scores were investigated. RESULTS: There was a significant increase in fatty infiltration (decrease in FCSA/CSA ratio) of the MF (P = 0.001) and SPL (P < 0.001) muscles at the level below the spinal cord compression. A significant increase in MF CSA asymmetry was also observed at the level below the compression. Lower MF FCSA/CSA ratio was associated with longer 30-m walking test time. Lower SCer FCSA/CSA was associated with corticospinal distribution motor deficits and atrophy of the hands. Greater asymmetry in SCap CSA was associated with higher Neck Disability Index (NDI) scores, whereas lower asymmetry in MF CSA was associated with a positive Hoffman sign and weakness. CONCLUSION: A significant increase in muscle fatty infiltration and CSA asymmetry at the level below the compression was observed in patients with DCM. Our results also suggest an association between cervical muscle morphology and DCM clinical symptoms and functional status. LEVEL OF EVIDENCE: 2.

Bedside ultrasound education in Canadian medical schools: A national survey.

BACKGROUND: This study was carried out to determine the extent and characteristics of bedside ultrasound teaching in medical schools across Canada. METHODS: A cross-sectional, survey-based study was used to assess undergraduate bedside ultrasound education in the 17 accredited medical schools in Canada. The survey, consisting of 19 questions was pilot-tested, web-based, and completed over a period of seven months in 2014. RESULTS: Approximately half of the 13 responding medical schools had integrated bedside ultrasound teaching into their undergraduate curriculum. The most common trends in undergraduate ultrasound teaching related to duration (1-5 hours/year in 50% of schools), format (practical and theoretical in 67% of schools), and logistics (1:4 instructor to student ratio in 67% of schools). The majority of responding vice-deans indicated that bedside ultrasound education should be integrated into the medical school curriculum (77%), and cited a lack of ultrasound machines and infrastructure as barriers to integration. CONCLUSIONS: This study documents the current characteristics of undergraduate ultrasound education in Canada.