The effectiveness and safety of conservative interventions for positional plagiocephaly and congenital muscular torticollis: a synthesis of systematic reviews and guidance

Congenital muscular torticollis (CMT) is a postural, musculoskeletal deformity evident at, or shortly after, birth. It results from unilateral shortening and increased tone of the sternocleidomastoid (SCM) muscle and presents as lateral flexion of the head to the ipsilateral side with rotation to the contralateral side [1]. It is potentially a painful condition for infants and can present with a pseudotumor in the SCM muscle [2]. It is the third most common congenital musculoskeletal condition in newborns with an incidence ranging from 0.3 to 16% [3]. CMT has been associated with dysfunction in the upper cervical spine and is sometimes referred to as kinetic imbalance due to subocciptal strain (KISS) [2]. Treatment approaches for CMT include manual therapy (including practitioner-led stretching exercises) [4], repositioning therapy (including tummy time) [1] and, in severe non-resolving cases, botulinum and surgery [5]. CMT can lead to secondary changes such as cranial asymmetry, and also to functional problems, including breastfeeding problems [2].

Cranial asymmetry, also known as plagiocephaly, is the most common form of ‘flat head syndrome’ and presents itself as an asymmetrical head shape. Positional plagiocephaly (PP) (sometimes referred to as deformational plagiocephaly or non-synostotic plagiocephaly) typically occurs in infants and results from mechanical factors which, when applied over a period of time in utero, at birth, or postnatally, alter the shape of the skull [6]. In this condition there is flattening of one side of the occiput, with anterior displacement of the ipsilateral ear. The region of occipital flattening relates to the side that the head is toward when in the supine sleeping position [7].

A rise in the prevalence of PP occurred after widespread implementation in western countries of the ‘Back to Sleep’ campaigns which recommended that healthy term infants be positioned on their backs during sleep [8] to prevent Sudden Infant Death Syndrome (SIDS). Prior to 1992, the incidence of the deformity was estimated at 1 in 300 infants [9]. Estimates for PP prevalence now range from 16 to 48% of typical healthy infants younger than 1 year depending on the diagnostic criteria used and 37.8% for infants aged between 8 and 12 weeks old [10]. Considering this large increase in the incidence of PP, there has been much interest in investigating, managing, and preventing this condition [7]. Although the optimal timing and modality of interventions have yet to be clearly established, primary treatments for plagiocephaly are nonsurgical and include observation, head repositioning, manual therapy (including practitioner-led stretching exercises), and helmet therapy/orthotic devices [8].

Head repositioning therapy is usually performed by the parents with the purpose of positioning the infant’s head on the non-flattened side and includes advice on ‘tummy time’ recommendations. Helmet therapy, sometimes referred to as orthotics or moulding therapy, generally uses a plastic helmet with the aim of reshaping the deformed skull to a normal shape without restricting the cranial growth [11, 12]. Manual therapies such as that given by chiropractors, osteopaths, physiotherapists and physical therapists centre on techniques administered passively to the infant either through cervical articulation and soft tissue muscle stretching to restore neck function and/or soft tissue tension release/reduction [13]. Manual therapies also include practitioner-led stretching exercises, whether administered directly by a practitioner or by a practitioner guided parent.

The relationship between CMT and PP is slightly unusual as causality can go in either direction and infants can suffer from both conditions at the same time. There are similarities between the management strategies for both PP and CMT but limited research exists on their effectiveness. In addition, clear treatment protocols which take severity of the condition and age of the infant into consideration are lacking. There is concern about both CMT and PP due to their association with developmental dysplasia of the hip, brachial plexus injury, foot or lower limb anomalies and cognitive and motor development [1, 14].

To investigate for congenital muscular torticollis (CMT) and positional plagiocephaly (PP) the effectiveness and safety of manual therapy, repositioning and helmet therapy (PP only) using a systematic review of systematic reviews and national guidelines.

We conducted a systematic review of systematic reviews and clinical guidelines for conventional treatments of both PP and CMT. We reviewed existing analyses of information whether it was based on compiled qualitative or narrative analyses, meta-analysis or guideline consensus review (PROSPERO registered number: CRD42019139074). We used the PRISMA statement to guide the structure of this review [15].

There were 232 studies selected for screening against title and abstract; of these 157 were for PP and 75 for CMT. Of the studies selected 140 were excluded leaving 92 for full paper review. A further 78 were excluded and 14 references were finally included in this systematic review. The final selection included 10 papers for PP and 4 for CMT. See Fig. 1.

There were 10 reviews in the final selection for positional plagiocephaly; 2 investigating effectiveness of manual therapy [8, 13], 3 for helmet therapy/orthotics [19, 21, 22], 1 for repositioning advice/therapy [18] and 4 papers which compared helmet therapy with repositioning [7, 11, 20, 23]. All of these reviews conducted a narrative analysis of their results.

There were 4 CMT reviews in the final selection which examined the effectiveness of manual therapy [10, 20, 23, 24]. However one review [24] searched for RCTs for Kinetic Imbalance for Sub-occipital Strain (KISS) syndrome which suggested that it is a component in both CMT and PP; they found no data to present on the treatment of this syndrome. Two of the reviews [10, 23] had data on one study only.

The characteristics of the final selection studies are shown in Tables 2 and 3.

The results for treatments for PP indicated that repositioning therapy had moderate to high quality level of evidence showing a mix of favourable and inconclusive findings. Manual therapy interventions had moderate to high quality evidence showing favourable outcomes when compared with repositioning therapy and positioning pillows [8] but equivocal low-level evidence findings when compared with standard care and helmet therapy. Helmet therapy was favourable for head shape change but the quality of these studies was low, indicating that there was uncertainty around these findings. The effectiveness of helmet therapy compared to manual therapy was inconclusive [20].

The results for CMT showed that manual therapy in the form of practitioner-led stretching had moderate favourable evidence for increasing range of movement and there was low quality inconclusive evidence to support SMT in addition to physiotherapy. Caution is required when interpreting the evidence for manual therapy for CMT as it only relies on one underpowered pilot study with methods that were inappropriate to assess effectiveness [28].

It is a mixed and confusing batch of evidence which is compounded with poor standardisation of measurement criteria for both PP and CMT and a lack of available guidance. The first line treatment recommended in the guidance reviewed for both PP and CMT were: parent education and support, positioning / tummy-time and physical therapy. Parent education and support centred on reassurance that in the majority of cases positional preference and head shape can resolve over time and may be helped with repositioning and physical therapy (all guidance). If the education and guidance centres on the premise of natural resolution, the foundation for arguments for any kind of treatment or intervention seems limited. However some concern has been raised about severe and moderate cranial asymmetry (positional plagiocephaly and brachycephaly) and later cognitive and academic outcomes: direct causality was not suggested, the authors postulated that moderate / severe PP could be a marker for developmental risk, meaning that those who develop plagiocephaly may be at risk of developmental problems [14]. This implies a greater need to standardise measurement and definitions of mild, moderate and severe PP to determine which babies may benefit from extra care, monitoring and treatment.

Repositioning (including tummy time) and stretching regimes make intuitive sense when considering a mechanistic explanatory model for a treatment intervention. They may also have a high placebo element of effect because the parents are able to play an active role in helping to resolve the baby’s condition [24], This does not, however, negate the need of practitioner input as parents often require advice, guidance and support to understand how and when to do the stretching and repositioning. Potential problems identified with the home exercises, repositioning and tummy time included adherence and ‘critical dose’ needed to make a change. The clinician or therapist delivering advice, guidance and support to parents does not have to be limited to one profession, especially if this allows for more access to support, advice and care.

There were no serious adverse events documented in any RCTs included in the systematic reviews we reviewed for manual therapies, repositioning and helmets. One study mentioned serious adverse events reported in case studies but causality between the manipulation treatment and the adverse events were inconclusive [4]. Minor adverse events were noted with helmet therapy, such as some skin irritation and rashes which may affect comfort and the infants’ tolerance to wearing the helmet. Given this information it seems sensible to consider conservative treatments as a first line option unless otherwise indicated.

There was also a suggested issue with positioning pillows and the potential associated risk of infants not sleeping on their back and sudden infant death syndrome. Several studies concluded that despite the moderate and favourable beneficial effects on head shape and symmetry with the use of positioning pillows, it did not outweigh the risk of sudden infant death syndrome [8, 24]. The Congress of Neurological Surgeons’ guidance recommended that manual therapy and repositioning be used rather than positioning pillows [8].

A limitation of reviews of reviews is that many of the same studies are repeatedly analysed, however we were able to compare the interpretation of findings between the different authors using the same studies. We noted that the authors consistently identified issues with non-standardised diagnostic criteria to classify levels of severity of PP and CMT and how the outcomes were measured, for example cranial asymmetry and/or cervical range of movement. We did not analyse these factors in this review, nor did we consider treatments for more severe cases of PP and CMT when an infant has clinical development or thriving issues (rather than observable mild cosmetic issues) that may indicate surgical interventions or botulinum. In addition, we did not review studies to fully comprehend meaningful change to the infants and their parents.

A strength of this review was that we compared synthesised evidence with the guidance and we noted that guideline recommendations were not fully grounded in high quality favourable evidence. We would concur with others [24] that there is some favourable, albeit low-quality evidence, of some benefit for manual therapy in the form of practitioner-led stretching for CMT only and repositioning for both PP and CMT with no reported serious adverse events, warranting that these should be considered in the first instance.

Further research is needed to understand when, and if, to intervene and the optimal stages of interventions for what kind of benefit, risk or discomfort to the infants. At present there is not enough robust data or evidence to fully inform guideline development. The most comprehensive attempt by the Congress of Neurological Surgeons [26] illustrated what a difficult and varied task it was to develop the guidance. They did three different systematic reviews to try and fully comprehend the literature surrounding PP.

Manual therapy for PP showed favourable outcomes when compared with repositioning therapy but equivocal low-level evidence when compared with helmet therapy. The results for CMT showed that manual therapy in the form of practitioner-led stretching had moderate favourable evidence for increasing range of movement but this evidence only relies on one underpowered pilot study. More well powered effectiveness and efficacy studies are needed.

Distinguishing between superiority of treatments was difficult due to the lack of standardised measurement systems, the variety of outcomes and limited high quality studies. There is still a need to have an accepted classification system for diagnosing and describing grades of PP and CMT to fully investigate when and if therapy is warranted and what change is a meaningful change. The type of treatment appropriate for the infants and the duration and dose of treatment is yet to be clearly determined.

Overall physical therapy such as stretches and/or exercises, repositioning and tummy-time may benefit some infants. Education, guidance and support is likely to reassure and help parents. Advice and guidance can be given by a variety of health care professional’s but clearly clinical training is necessary to ascertain whether the infants are healthy and thriving with no underlying pathologies before conservative approaches and/or treatments are recommended.