Informing the Update to the Physical Therapy Management of Congenital Muscular Torticollis Evidence-Based Clinical Practice Guideline: A Systematic Review

Abstract

Purpose:

To systematically review the recent evidence on physical therapy diagnosis, prognosis, and intervention of congenital muscular torticollis to inform the update to the physical therapy management of congenital muscular torticollis evidence-based clinical practice guideline.

Methods:

Seven databases were searched for studies from 2012 – 2017 that informed PT diagnosis, prognosis or intervention of infants and children with CMT. Studies were appraised for risk of bias and quality.

Results:

Twenty studies were included. No studies informed PT diagnosis. Fourteen studies informed prognosis, including factors associated with: presence of a sternocleidomastoid lesion, extent of symptom resolution, treatment duration, adherence to intervention, cervical spine outcomes, and motor outcome. Six studies informed intervention including: stretching frequency, microcurrent, kinesiology tape, group therapy and post-operative PT.

Conclusions:

New evidence supports that low birth weight, breech presentation and motor asymmetry are prognostic factors associated with longer treatment duration. Higher-level evidence is emerging for microcurrent intervention.

INTRODUCTION

Congenital muscular torticollis (CMT) is a postural, musculoskeletal deformity evident at or shortly after birth. CMT results from unilateral shortening or stiffness of the sternocleidomastoid (SCM) muscle and presents as lateral flexion of the head to the ipsilateral side with rotation to the contralateral side. The incidence of CMT ranges from 0.3%¹ to 16%² of newborns. It is the third most common congenital musculoskeletal condition in newborns.³

Extensive evidence supports that physical therapy (PT) intervention is effective in resolving CMT when initiated in early infancy. However if initiated later, CMT resolution decreases and treatment duration increases.⁴ When PT is initiated before 1 month of age, the prognosis for typical cervical range of motion (ROM) is 98% with 1½ months of PT.⁴ However when initiated from 1 to 3 months, the prognosis for typcial cervical ROM decreases to 89% with 6 months of PT; when initiated from 3 to 6 months, it decreases to 62% with 7 months of PT; and when initiated over 6 months of age, it decreases to <20% with 10 months of PT.⁴ Therefore, it is imperative that infants with CMT are identified early and receive appropriate PT intervention for optimal outcomes.

Physical Therapy Management of Congenital Muscular Torticollis: An Evidence-Based Clinical Practice Guideline from the Academy of Pediatric Physical Therapy of the American Physical Therapy Association was published in 2013 (2013 CMT CPG).⁵ The 2013 CMT CPG informed referral, screening, examination and evaluation, diagnosis, prognosis, intervention, consultation, discharge and follow-up of infants with CMT. Recommendations were summarized into 16 action statements based on critical appraisal of the literature and expert opinion. The guideline development group and best practice indicate that clinical practice guidelines be updated every 5 years as evidence becomes available.⁶

The purpose of this study is to systematically review the recent evidence on PT diagnosis, prognosis and intervention of CMT to inform the update to the physical therapy management of congenital muscular torticollis evidence-based clinical practice guideline.

METHODS

Search Strategy

This systematic review was conducted according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).⁷ The search strategy for this update of the 2013 CMT CPG was similar to the original search to ensure consistency. A comprehensive search of seven databases (CINAHL, Clinical Trials, Cochrane Library, Embase, PsycInfo, PubMed, Web of Science) was conducted from January 2012 to September 2017 by a clinical services librarian. Medical subject headings (MeSH) and non-MeSH search terms were used, including torticollis, physical therapy, diagnosis, prognosis and intervention. Refer to Supplemental Digital Content 1 for full search strings by database. No filters were applied for study type or language. Additional studies were identified through a manual search of the references of included studies.

Selection Criteria

Studies meeting these criteria were included: (1) participants included infants and children diagnosed with CMT, (2) informed the diagnosis, intervention or prognosis of CMT as related to PT. Studies were excluded based on the following criteria: (1) only on plagiocephaly, (2) dissertations and abstracts, (3) not published in English, (4) included in the 2013 CMT CPG.⁵

Study Selection

Studies were included based on title or abstract using the inclusion and exclusion criteria. If necessary, a full text review of the article was completed. Two authors coded the first 10% of studies (n=206) to establish reliability for study selection. Discrepancies were resolved through discussion. The two authors then independently reviewed the remaining articles (n=1,856).

Study Appraisal

Study validity was appraised using: the Quality in Prognostic Studies tool (QUIPS)⁸ for prognostic studies, or the American Physical Therapy Association’s Critical Appraisal Tool for Experimental Intervention Studies (CAT-EI) and the Cochrane Risk of Bias⁹ for intervention studies. Eight reviewers completed appraisals of 3 articles to establish inter-rater reliability. Reviewers with ≥90% agreement were randomly assigned to appraise the remaining studies. Two reviewers appraised each study independently, scores were compared for agreement, and discrepancies were resolved via discussion. Details of the risk of bias for prognostic studies are included in Table 1 and for intervention studies in Tables 2 and 3. Additionally, intervention study designs were appraised and assigned a level of design rigor (level I, most rigorous, to level V, least rigorous) according to criteria from the American Academy of Cerebral Palsy and Developmental Medicine (AACPDM) Systematic Review Methodology.¹⁰

Table 1.

Quality in Prognostic Studies Tool

Key: green = low risk of bias, yellow = moderate risk of bias, red= high risk of bias

Table 2.

Cochrane Risk of Bias Tool for Quality Assessment of Intervention Studies

Key: green = low risk of bias, yellow = unclear risk of bias, red= high risk of bias

Table 3.

Quality Rating of Outcomes based on APTA Critical Appraisal Tool for Experimental Intervention

Key: green = high quality study, yellow = acceptable quality study, orange = low quality study, red= unacceptable quality

Abbreviations: AP= arthrodial protractor, MFS = Muscle Function Score, (P)ROM = (passive) range of motion, SCM = sternocleidomastoid muscle, SE= sonoelastography, SSAP = severity scale for assessment of plagiocephaly, Subj = subjective, US = ultrasound

Data Extraction

Mutual consensus was used to determine the applicable data to be extracted from each study by two reviewers. Data extracted for prognostic studies included: study design, purpose, inclusion/exclusion criteria, number of participants, timing of measures, intervention, independent variables, dependent variables, statistics, results and clinical implications. Data extracted for intervention studies included: study design, purpose, inclusion/exclusion criteria, number of participants, intervention, outcome measures, timing of measures, results for each outcome measure and clinical implications. Data was independently extracted by two reviewers. Extracted data was compared for agreement, and discrepancies were resolved via discussion.

RESULTS

The results of the search are in Figure 1. The search identified 2,064 studies with 1,760 studies remaining after duplicates were removed. An additional 1,738 studies were excluded based on title or abstract. Twenty-two articles underwent full-text review, with 20 included in the systematic review. From the final list of included studies, 0 studies informed diagnosis, 14 studies informed prognosis, and 6 studies informed intervention. Details of prognostic studies that address treatment duration are in Table 4 and details of intervention clinical trials are in Table 5.

Fig. 1.

PRISMA flow diagram.

Table 4.

Prognostic Evidence for Treatment Duration

Author & Year	Study Design	Participants	N=	Outcome	Treatment	Statistics	Results: Significant Prognostic Factors	Results: Non-Significant Prognostic Factors	Clinical Implications
Han et al 201711	Retrospective Cohort	CMT	182	Full neck PROM and no tilt	SCM lesion- manual stretching for ROT and LAT FLEX & active strengthening; 2–3x/wk No lesion- manual stretching into LAT FLEX & strengthening with postural reactions; 2–3x/wk	Chi Squared; T-test	Shorter tx for nonlesion group	Sex, method of delivery, gestational age, DDH, birth weight	Longer tx duration associated with presence of SCM lesion
Hong et al 201616	Retrospective Cohort	CMT < 3 mo, palpable neck mass	53	LAT FLEX and ROT < 5° difference side-to-side	Manual stretching and SCM massage 2x/wk for 30 min + HEP	Spearman correlation coefficient	Strain Ratio	SCM muscle thickness, SCM thickness ratio	Longer tx duration associated with increased SCM stiffness
Jung et al 201519	Cohort	CMT	118	LAT FLEX and ROT ROM <5° difference side-to-side	2 x/wk for 30 min of LAT FLEX and ROT PROM + HEP of PROM and active EX	Pearson correlation	Fetal presentation, age at diagnosis, birth weight, SCM thickness, SCM thickness ratio	Sex, involved side, methods of delivery, DDH, facial asymmetry, DP, gestational age, LAT FLEX and ROT PROM	Longer tx duration associated with breech fetal presentation, younger age at diagnosis, lower body weight, thicker SCM, and higher SCM thickness ratio
Lee et al 201518	Cohort	CMT<6m with palpable neck mass or limited ROT PROM	102	Not reported	3x/week for 30 min therapeutic US, manual stretching, massage, and passive stretching	Pearson Correlation Coefficient	preDifference in SCM thickness, preHead Tilt, preTOA, change in SCM thickness, change in Head Tilt, change in TOA	None	Longer tx duration associated with increased SCM thickness, increased head tilt, and lower TOA scores
Lee et al 201617	Retrospective Cohort/Case Control	CMT≤ 6 mo with ROT and LAT FLEX ROM limitation >10°, completed OP PT	149	Tx duration: ROT & LAT FLEX ≤ 5° difference or did not respond after 6 mo tx or at 12 mo of age; measured monthly	Manual stretching 30 minutes 3x/wk: flexion, rotation, lateral flexion, and extension 3 × 15 reps for 1 sec with 10 second rest between; Active symmetric neck positioning at home without stretching	Pearson Correlation Coefficient; ANCOVA	Adjusted for age at presentation and initial ROT & LAT FLEX PROM limitation, duration shorter in US normal	None	Shorter tx duration associated with US normal group when adjusted for initial ROT, LAT FLEX and age at presentation
Watemberg et al 201620	Retrospective Cohort	Infants with congenital postural torticollis	173	Functional motor asymmetry as assessed by reduced volitional motor activity of one or both limbs on one side with no weakness or spasticity	None	Chi squared; T-test	Delayed motor development and DP more common in infants with functional asymmetry, significantly longer tx duration in asymmetry	Age of diagnosis, torticollis side, family history, shoulder girdle weakness, axial hypotonia, increased muscle tone	Longer tx duration for infants with congenital postural torticollis and functional motor asymmetry

Abbreviations: ANCOVA= analysis of covariance, CMT = congenital muscular torticollis, DDH= developmental dysplasia of the hip, DP = deformational plagiocephaly, EX = exercise, HEP = home exercise program, LAT FLEX= cervical lateral flexion, min = minute, mo= month, OP= outpatient, (P)ROM = (passive) range of motion, PT= physical therapy, reps = repetitions, ROT= cervical rotation, SCM = sternocleidomastoid muscle, sec = seconds, TOA= Torticollis Overall Assessment, tx = treatment, US = ultrasound, wk = week, x = times, + = plus, / = per

Table 5.

Intervention Evidence

Author & Year	Level of Evidence	Study Design	Participants	N=	Experimental vs. Comparison Groups	Intervention	Home Program	Outcomes (measurement tool)	Results (between group differences)	Clinical Implications
Giray et al 201627	Level II	RCT	CMT, 3–12 mo	33	(1) EX+ inhibitory KT on involved SCM (n=12) (2) EX+ inhibitory KT on involved SCM + facilitation KT on uninvolved SCM (n=10) (3) EX Only (n=11)	30 min EX (ROM; stretching affected SCM 3×15 reps [ROT & LAT FLEX], 1 sec hold with 5–10 sec rest; strengthening unaffected SCM; handling strategies; ball ex) 2x/wk for 3 wks; KT applied after EX as per group assignment	Parents instructed on how to perform Intervention; performed 3x/day during 3 mo follow up period	ROT & LAT FLEX PROM (AP), LAT FLEX Strength (MFS), Craniofacial asymmetry (SSAP)	ROT: NS LAT FLEX: NS STRENGTH: NS CRANIOFACIAL: NS	KT provided no added benefit to PT intervention
He et al 201625	Level II	RCT	CMT< 3 mo, limited cervical ROM	50	(1) 50x stretching (n=24) (2) 100x stretching (n=26)	5–10 day training then parents implemented at home: 10 rot and lat flex stretches, 10–15 sec hold, 5 or 10 x/day as per group assignment	Same as Intervention	ROT & LAT FLEX PROM (AP), Head Tilt (AP), LAT FLEX Strength (MFS), SCM Muscle Thickness (US)	ROT: 100x group greater improvement at 1 and 2 mo post-tx (P < 0.05) LAT FLEX/HEAD TILT: 100x group greater improvement at 1 and 2 mo post-tx (P < 0.05) STRENGTH: NS SCM Thickness: NS	Increased frequency of daily stretching resulted in decreased head tilt and increased ROT & LAT FLEX PROM
Kwon and Park 201426	Level II	RCT	CMT < 3 mo with entire SCM involvement, palpable SCM mass	20	(1) EX + US + Microcurrent on (n=10) (2) EX + US + Microcurrent off (n=10)	3 x/ wk; US diathermy 5 min + EX (ROM, postural training, manual SCM stretching [3 × 15 reps, 1 sec hold, 5–10 sec rest]) 20 min + Microcurrent 30min (on/off)	ROT & LAT FLEX stretches, 10x/session, 6x/day; Positioning and handling to promote ROT towards affected SCM	ROT PROM (AP); SCM thickness, CSA & red pixel intensity (SE); tx duration	ROT: 1,2,3 mo post-tx was significantly greater in microcurrent group vs. control; NS at 6 mo SCM thickness, CSA, red pixel intensity: 3 mo post-tx significant differences in microcurrent group vs. control Tx duration: shorter in microcurrent group (2.6 mo) compared to control (6.3 mo)	The addition of microcurrent resulted in shorter tx duration
Ohman et al 201528	Level II	RCT	CMT ≤12 mo with LAT FLEX muscle imbalance	29	(1) Inhibitory KT on involved SCM (n=16) (2) No KT (n=13)	KT muscle relaxation technique to involved SCM; No EX	None	LAT FLEX Strength (MFS)	STRENGTH: Significant difference between groups with KT applied (P < .0001); Significantly lower scores on the involved side with KT (P < .0001) & significantly higher scores on the uninvolved side after taping (P= .01)	KT for muscle relaxation resulted in improved LAT FLEX AROM against gravity

Abbreviations: AP= arthrodial protractor, CMT = congenital muscular torticollis, CSA = cross sectional area, EX = exercise, KT = kinesiology taping, LAT FLEX= cervical lateral flexion, MFS = Muscle Function Score, min = minute, mo= month, NS = not significant (p>.05), (A/P)ROM = (active/passive) range of motion, RCT = randomized control trial, reps = repetitions, ROT= cervical rotation, SCM = sternocleidomastoid muscle, SE= sonoelastography, sec = seconds, SSAP = severity scale for assessment of plagiocephaly, tx = treatment, US = ultrasound, wk = week, x = times, + = plus, / = per

Prognostic Studies

Fourteen studies informed prognosis related to the presence of a SCM lesion, extent of symptom resolution, treatment duration, adherence to PT intervention, cervical spine outcome, and motor outcome.

Presence of SCM Lesion.

Han et al¹¹ compared clinical characteristics of infants with CMT with and without a SCM lesion on ultrasonography. Infants with a SCM lesion, compared to infants without a SCM lesion, demonstrated a younger age of presentation for medical care, greater limitations in cervical rotation and lateral flexion ROM, a greater number of breech presentations, lower proportion of cesarean sections and a decreased prevalence of plagiocephaly.¹¹

Extent of symptom resolution.

Ryu et al¹² investigated the relation between clinical factors and symptom resolution, as quantified by no visible SCM lesion on follow-up ultrasonography. PT intervention was the only factor that correlated with complete resolution of the SCM lesion in infants with CMT.¹²

Lee et al¹³ investigated the relation between age at initiation of treatment and symptom resolution, as quantified by post-intervention head tilt, thickness ratio of the involved/uninvolved SCM, and Torticollis Overall Assessment (TOA) scores. The TOA combines rotation and lateral flexion ROM, craniofacial asymmetry, SCM muscle quality, head tilt and subjective assessments by parents into a single scaled score. In this study, infants with CMT under 6 months were separated into 2 groups based on age at initiation of treatment: before 6 weeks and after 6 weeks. Infants who initiated treatment before 6 weeks, compared to after 6 weeks, demonstrated decreased thickness ratio of the involved/uninvolved SCM post-intervention.¹³ There were no between-group differences for head tilt and TOA scores post-intervention.¹³

Lee et al¹⁴ investigated the relation between severity of pre-intervention neck rotation asymmetry and symptom resolution, as quantified by mid and post-intervention head tilt and TOA scores. Infants with CMT were separated into 3 groups based on severity of pre-intervention neck rotation asymmetry: <15°, 15 to 30°, >30° difference between passive cervical rotation ROM of right and left sides. All groups received PT intervention for 6 months. Between-group differences for TOA scores were observed both mid and post-intervention among all groups; increased severity of initial neck rotation asymmetry was associated with decreased TOA score (lower scores reflect poorer outcomes).¹⁴ There were no between-group differences for head tilt mid and post-intervention.¹⁴

Park et al¹⁵ investigated the association between SCM muscle thickness and post-intervention neck passive range of motion (PROM) assessed using the modified Cheng score, which combined neck rotation and lateral flexion PROM into a single scaled score. The involved SCM thickness pre-intervention, involved/uninvolved SCM thickness ratio pre-intervention, change in involved SCM thickness pre to post-intervention, and change in involved/uninvolved SCM thickness ratio pre to post-intervention were each moderately correlated with the modified Cheng score.¹⁵ The involved/uninvolved SCM thickness ratio pre-intervention demonstrated the highest correlation with the post-intervention modified Cheng score, supporting that this measure may be more accurate than the pre-intervention involved SCM thickness alone to predict the extent of neck PROM resolution.¹⁵

Treatment duration / episode of care.

Six studies reported factors associated with treatment duration.^11,16–20 A total of 777 infants participated in the studies with sample sizes ranging from 53¹⁶ to 182¹¹ participants. All study participants were infants with CMT under the age of 1 year. For 5 studies,^11,16–19 intervention consisted of manual stretching, strengthening, massage, positioning, therapeutic ultrasound (US), and/or active range of motion (AROM) activities provided 2 to 3 times per week. One study did not provide details on the intervention.²⁰

Longer treatment duration was correlated with each of the following pre-intervention factors: lower birth weight,¹⁹ younger age at diagnosis,¹⁹ increased stiffness of the involved SCM,¹⁶ increased thickness of the involved SCM,¹⁹ increased thickness ratio of the involved/uninvolved SCM,^18,19 increased degree of head tilt,¹⁸ and lower scores on the TOA.¹⁸ In addition, longer treatment duration was reported in the following groups of infants: infants with breech, compared to cephalic, presentation;¹⁹ infants with motor asymmetry, compared to without motor asymmetry;²⁰ and infants with an SCM lesion present on ultrasonography, compared to infants without an SCM lesion.¹¹

Treatment duration was significantly shorter in a group of infants with CMT with normal SCM findings on ultrasonography, compared to a group with abnormal SCM findings, when adjusting for the following pre-intervention factors: neck rotation PROM, neck lateral flexion PROM and age at diagnosis.¹⁷

Adherence to intervention.

Rabino et al²¹ investigated factors associated with adherence to PT intervention for mothers of infants with CMT. Adherence was quantified as the proportion of prescribed exercises performed, the proportion of visits attended, and whether treatment was terminated by the clinician or prematurely by the parents. Adherence was associated with maternal perceptions of the effect of CMT on the infant’s activities and the intervention’s importance for the infant’s future function.²¹ Adherence was not related to the mother’s level of communication with the therapist, trust in the therapist, belief in the program or preference of whether or not to be involved in the treatment. ²¹

Cervical spine outcome.

Ohman²² assessed 58 children with a history of CMT at preschool age. Only 7% exhibited a head tilt, but 26% had some degree of asymmetry in PROM.²² The clinical significance of the asymmetric neck PROM is questionable since all children had at least 85° of rotation to each side, and the 7 children with a lateral flexion difference had a difference between sides of only 5–10°.²² Asymmetric neck PROM at preschool age was associated with the degree of asymmetric neck rotation PROM as an infant.²²

Motor outcome.

Three studies informed the association of CMT with gross motor outcome.^20,23,24 In a retrospective analysis, Watemberg et al²⁰ found that at initial evaluation, delayed motor development was significantly more common in infants with postural CMT with functional asymmetry, versus without asymmetry.²⁰

Cabrera-Martos et al²⁴ investigated the acquisition of 4 gross motor skills (rolling, sitting, crawling, standing without support) for 3 groups of infants: infants with deformational plagiocephaly (DP) and acquired CMT, infants with DP and congenital CMT, and infants with DP alone. When controlling for age at referral and severity of DP, all groups demonstrated similar age at initiation of rolling and sitting.²⁴ Infants with DP and CMT (acquired and congenital) crawled and stood without support earlier than infants with DP alone.²⁴

Ohman and Beckung²³ investigated the association of CMT with gross motor development at preschool age. History of CMT during infancy was not associated with gross or fine motor delays at 3.5 to 5 years, as assessed using the Movement Assessment Battery for Children (MABC-2).²³

Intervention Studies

Five studies informed intervention, including neck PROM, microcurrent, kinesiology taping, group therapy, and post-surgical intervention.

Neck passive range of motion.

He et al²⁵ informed dosage of neck stretching. This randomized control trial (RCT) compared stretching 50 times a day to stretching 100 times a day. Both dosages resulted in improved head tilt, neck PROM and decreased SCM thickness in infants with CMT.²⁵ However, stretching 100 times a day resulted in greater improvement in head tilt and neck PROM.²⁵

Microcurrent.

Kwon and Park²⁶ informed the use of microcurrent. This RCT compared therapeutic exercise and US with or without additional microcurrent. The group receiving microcurrent demonstrated a shorter treatment duration, improved neck rotation PROM, and decreased involved SCM thickness, cross sectional area, and red pixel intensity.²⁶

Kinesiology taping.

Two RCTs informed the use of kinesiology taping (KT). One RCT compared exercises with KT applied to the involved SCM for inhibition, KT applied to the involved SCM for inhibition and to the uninvolved SCM for facilitation, and no KT.²⁷ All 3 groups demonstrated improved neck PROM, MFS scores and Plagiocephaly Severity Scale scores with no significant differences between groups.²⁷ One exception was that there was no improvement in neck rotation PROM in the group with the KT applied to both SCMs.²⁷

Another RCT compared the immediate effects of KT applied to the involved SCM for inhibition with a comparison group without KT application.²⁸ The KT group, versus the comparison group, demonstrated improved symmetry in active neck lateral flexion strength as indicated by a significantly lower MFS score on the involved side and a significantly higher MFS score on the uninvolved side.²⁸

Group therapy.

Surprenant et al²⁹ informed use of group therapy. This cohort study evaluated the use of a group-based, team service delivery model for caregivers of 35 infants with CMT. Results indicated significant improvements in the infants’ preferred resting head position, head shape, head tilt and facial asymmetry.²⁹ Additionally, parents exhibited significant gains in knowledge of CMT and reported that they were very satisfied with the group program, rating it excellent quality.²⁹

Post-surgical intervention.

Oledzka and Suhr³⁰ informed postsurgical PT intervention of CMT. This case report described intervention of two 2-year old children, status post SCM surgical release. The children received PT intervention for 3 and 11 months for pain management, functional mobility, ROM, strengthening, activities to promote midline, vestibular treatment, scapular stabilization, bimanual activities, proprioception exercises, Kinesiotaping® and use of TOT collar™. At the first postoperative visit with the surgeon, a soft cervical collar was discontinued and a pinless halo was initiated until 10–12 weeks post-surgery. Families were provided with a daily home program. Both children achieved full ROM, symmetrical cervical strength, midline head position, performed transitions with symmetrical head righting, and demonstrated age-appropriate gross motor skills.³⁰

DISCUSSION

The findings from this systematic review inform six action statements in the 2013 CMT CPG.⁵ The discussion will be organized by each action statement.

Action Statement 3: document infant history

The 2013 CMT CPG⁵ recommends documenting 9 specific health history factors. This review provides additional support for documenting age at initial visit^13,17,19, and delivery history, including birth presentation and history of breech presentation,¹⁹ since these variables have been associated with either symptom resolution and/or treatment duration. This review adds that delivery history should include low birth weight¹⁹ as this has been associated with a longer treatment duration.

Action Statement 9: examine activity and developmental status

The 2013 CMT CPG⁵ cautioned that infants with CMT may be at risk for delays in early motor development.³¹ Ohman et al³¹ found that infants with CMT had lower scores on the Alberta Infant Motor Scales (AIMS)³² at 2 and 6 months when compared to infants without CMT. However, they noted the risk of delay seemed to be more associated with little or no time in prone while awake, than with CMT.³¹ In addition, gross motor function was not different between groups at 10 and 18 months of age.³¹ In this review, Cabrera-Martos et al²⁴ found similar age of attainment of rolling and independent sitting among infants with CMT and DP versus infants with DP alone. However, infants with CMT and DP stood and walked earlier than those with DP alone. It is important to note that the 95% confidence interval for walking in the DP alone group was 12.8 to 14.35, which is considered within normal limits for walking attainment.

Action Statement 11: determine prognosis

The 2013 CMT CPG⁵ states that prognoses for the extent of symptom resolution, the episode of care, and/or the need to refer for more invasive interventions are related to the age of initiation of treatment, classification of severity, intensity of intervention, presence of comorbidities, rate of change, and adherence with home programming.⁵

The results of this review provide additional support that PT intervention is critical for complete resolution of the muscular lesion of CMT in infants¹² and that infants achieve improved symptom resolution with earlier age of initiation of treatment.¹³ This review provides further support for the first 3 grades of the classification of severity proposed in the 2013 CMT CPG.⁵ In the 2013 CMT CPG, infants under the age of 6 months are classified into 3 groups based on pre-intervention passive neck rotation asymmetry: Grade 1 (<15°), Grade 2 (15 to 30°), and Grade 3 (>30°).⁵ These are the same 3 groups used by Lee et al,¹⁴ who found that increased severity of initial neck rotation asymmetry between right and left sides was associated with decreased symptom resolution as assessed using the TOA score. This review also adds that the involved/uninvolved SCM thickness ratio pre-intervention may be more accurate than the pre-intervention involved SCM thickness alone to predict the extent of neck PROM resolution.¹⁵

The results of this review confirm that the episode of care or treatment duration is related to the extent of the fibrous mass.^11,14,16,19 Infants with a SCM lesion, compared to those without a lesion, exhibit longer treatment duration,¹¹ and increased stiffness and thickness of the involved SCM is associated with longer treatment duration.^14,16,19 The results of this review add that history of breech presentation,¹⁹ low birth weight¹⁹ and presence of motor asymmetry²⁰ are also associated with increased treatment duration. Contrary to the literature in the 2013 CMT CPG⁵ that associated shorter treatment duration with younger age of initiation of treatment,^4,33–35 Jung et al¹⁹ found that younger age of initiation of treatment resulted in longer treatment duration. The authors of this study noted that that the participants with more severe symptoms were referred for assessment earlier than those with less severe symptoms, which may explain this finding.¹⁹

Action Statement 12: provide the following 5 components as the first-choice intervention

The 2013 CMT CPG⁵ states that the PT plan of care for infants with CMT or postural asymmetry should minimally address the following 5 components: neck PROM, neck and trunk AROM, development of symmetrical movement, environmental adaptations and parent/caregiver education. The findings from this systematic review further support the recommendations for neck PROM as a component of the first choice intervention. Our results add that increased frequency of neck PROM exercises may result in improved outcomes.²⁵ Our results also add that to increase adherence to PT intervention, therapists should educate parents on the effect of CMT on the infant’s activities and the intervention’s importance for the infant’s future function.²¹

Action Statement 13: provide supplemental interventions, after appraising appropriateness for the infant, to augment the first-choice intervention obtained

The 2013 CMT CPG⁵ states that supplemental interventions may be added when first-choice intervention have not improved ROM or postural alignment, when access to services is limited, or when the infant is unable to tolerate the intensity of the first-choice intervention. This review provides higher-level RCT evidence for the use of microcurrent in addition to PT to improve outcomes and reduce treatment duration for infants with CMT,²⁶ but suggests that KT may not provide added benefit when added to PT intervention.²⁷ While higher-level evidence is emerging on microcurrent and KT, further research is needed.

Action Statement 16: provide follow-up screening of infants 3 to 12 months post-discharge

The 2013 CMT CPG⁵ recommends a follow up reassessment after discontinuation of direct physical therapy intervention to examine positional preference, structural and movement symmetry, and developmental milestones.

This review provides support for reassessment after discontinuation of direct PT, since a residual head tilt and neck PROM asymmetries were noted in a cohort of preschool children with a history of CMT.²² Specifically, infants with greater neck rotation PROM asymmetries may be at greater risk for neck PROM asymmetries at preschool age.²²

This review also supports that a history of CMT was not associated with gross or fine motor delays at 3.5 to 5 years as assessed by the MABC-2.²³ However, a study by Schertz et al³⁶ found that a cohort of 7 to 9 year old children with a history of CMT had a greater prevalence of attention deficit hyperactivity disorder and developmental coordination disorder than would be expected in the general population. Type of CMT (SCM mass or tightness versus postural CMT) did not predict risk for a neurodevelopmental disorder, but children with a history of postural torticollis had significantly lower mean scores on the MABC.³⁶ Although more evidence is needed, a follow-up reassessment as recommended by the 2013 CMT CPG,⁵ is warranted to assess for asymmetries or developmental delays.

Limitations

Incomplete retrieval of references through database searching constituted a limitation at the review level. Manual search via cross-referencing relevant studies was undertaken to address this limitation.

CONCLUSIONS

This review provides new evidence supporting that low birth weight,¹⁹ breech presentation¹⁹ and presence of motor asymmetry²⁰ are prognostic factors associated with longer treatment duration. New evidence also supports that increased stretching frequency results in improved outcomes for infants with CMT.²⁵ Higher-level evidence is emerging on microcurrent;²⁶ however, further evidence is needed to establish its efficacy.