Changes in Muscle Stiffness in Infants with Congenital Muscular Torticollis.

Hwang Hwang,Choi Choi,Jung Jung,Shin Shin,Yang Yang

doi:10.3390/diagnostics9040158

Abstract

Congenital muscular torticollis (CMT) results from unilateral shortening of the sternocleidomastoid (SCM) muscle, usually associated with a fibrotic mass. Although CMT may resolve with physical therapy, some cases persist, resulting in long-term musculoskeletal problems. It is therefore helpful to be able to monitor and predict the outcomes of physical therapy. Shear-wave velocity (SWV) determined by acoustic radiation force impulse (ARFI) elastography can provide a quantitative measure of muscle stiffness. We therefore measured SCM SWV in 22 infants with unilateral CMT before and after 3 months of physical therapy and evaluated the relationships between SWV and SCM thickness and various clinical features, including cervical range of motion (ROM). SWV was initially higher and the ROM was smaller in affected muscles before physical therapy. SWV decreased significantly (2.33 ± 0.47 to 1.56 ± 0.63 m/s, p < 0.001), indicating reduced stiffness, and muscle thickness also decreased after physical therapy (15.64 ± 5.24 to 11.36 ± 5.71 mm, p < 0.001), both in line with increased neck ROM of rotation (64.77 ± 18.87 to 87.27 ± 6.31°, p < 0.001) and lateral flexion (37.50 ± 11.31 to 53.64 ± 9.41°, p < 0.001). However, the improved ROM more closely reflected the changes in SWV than in muscle thickness. These results suggest that a change in SWV detected by ARFI elastography could help to predict improvements in clinical outcomes, such as stiffness-related loss of motion, in patients with CMT undergoing physical therapy.

Highlights

Congenital muscular torticollis (CMT) is a common muscular disorder occurring at or shortly after birth as a result of unilateral shortening of the sternocleidomastoid (SCM) muscle [1]
Twenty-two infants (14 boys, 8 girls) with unilateral neck masses of the SCM who were diagnosed with CMT from August 2016 to August 2017 were enrolled in this study (Table 1)
The results of the current study showed that the initial acoustic radiation force impulse (ARFI) Shear-wave velocity (SWV) of the affected SCM was faster than that of the unaffected SCM in infants with CMT, and the degrees of neck rotation and lateral flexion were smaller on the affected compared with the unaffected side

Summary

Introduction

Congenital muscular torticollis (CMT) is a common muscular disorder occurring at or shortly after birth as a result of unilateral shortening of the sternocleidomastoid (SCM) muscle [1]. Shortening of the SCM causes clinical symptoms including head tilt toward the ipsilateral side and chin rotation to the opposite side [2]. Various causes of CMT have been reported, including traumatic delivery, primary myopathy, fibrosis due to peripartum bleeding, intrauterine postural abnormality, and intrauterine or perinatal compartment syndrome theory and the hereditary hypothesis; the exact etiology of CMT remains unclear [1,4,5]. Macdonald et al classified SCM patients as having either fibromatosis colli with palpable mass or idiopathic muscular torticollis with shortening of the SCM without a mass [6,7].

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Results

Discussion

Conclusion