Changes in Muscle Stiffness in Infants with Congenital Muscular Torticollis

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.

Evaluation of the Clinical Role of Strain Elastography in Patients Diagnosed With Congenital Torticollis

“…The effect of SCM, in these torticollis cases, was similar to other studies in the literature. 10,11,14 In this study, muscle echogenicity was found to be isoechoic in most of the recruited patients. Isoechoic patient cases were followed by hyperechoic example.…”

“…The specific etiology of CMT is uncertain. 3,11 Venous compression of the neck, fibrous hemorrhages in the peripartum period, and primary myopathy during the intrauterine period may have pathologic linkage. 12 Histologic examination of surgically resected materials has revealed atrophy and fibrosis in cases developed due to intrauterine venous compression.…”

“…There are publications in the literature in which torticollis cases are evaluated by SE. 1,10,11,14 This study has the potential to contribute to the evidence of strain elastography being conducted within this patient population.…”

Use of Shear Wave Elastography in Pediatric Musculoskeletal Disorders

“…Although CMT is a muscle-derived condition, the insufficient number of muscle SWE studies addressed the SCM stiffness indicates a large gap in the literature. It was reported that the stiffness of the affected SCM was positively correlated with the degree of PROM deficit of neck rotation in the affected side [39][40][41] and affected SCM stiffness was significantly higher than that of the unaffected SCM and than that in the control group [39]. Hwang et al also reported that SCM stiffness decreased significantly after 3 months of physiotherapy [41].…”

Is Longstanding Congenital Muscular Torticollis Provoking Pelvic Malalignment Syndrome?

“…It was reported that there was a positive correlation between the severity of scoliosis and pelvic obliquity in patients with adolescent idiopathic scoliosis. There were some children seen with both secondary scoliosis and pelvic asymmetry among the children with a history of CMT [ 19 ].…”