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Congenital Muscular Torticollis - Sternocleidomastoid Release

Surgical technique guide for sternocleidomastoid release in congenital muscular torticollis - unipolar and bipolar release, danger structures, paediatric considerations and the exclusion of non-muscular torticollis

Core Procedure
intermediate
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High-yield overview

Unipolar or bipolar release of the sternocleidomastoid for persistent congenital muscular torticollis | intermediate

Surgical Imaging

Critical Danger Structures and Exam Traps

Direction of the Deformity

The trap: Confusing which way the head tilts and the chin turns - this determines the operative side.

The fix: The contracted SCM pulls the mastoid toward the sternoclavicular joint, so the head TILTS toward the affected (tight) side and the chin ROTATES AWAY to the opposite side. Operate on the side TOWARD which the head is tilted (the short, tight muscle), not the side the chin points to.

Carotid Sheath - Inferior Release

Location: The carotid sheath (common carotid artery, internal jugular vein and vagus nerve) lies immediately deep and medial to the sternal and clavicular heads of the SCM at the level of the inferior release.

Risk: Plunging deep to the muscle during the clavicular/sternal release can injure the great vessels. Divide the heads superficially under direct vision, staying on the muscle, with the deep structures protected by a retractor.

External / Anterior Jugular Vein

Location: The external jugular vein crosses the superficial surface of the SCM obliquely; the anterior jugular veins run near the midline and lower neck.

Risk: These thin-walled veins bleed readily and obscure the field at the inferior release. Identify, ligate or coagulate them rather than avulsing them; air embolism is a theoretical risk with open neck veins in the head-up position.

Spinal Accessory Nerve (CN XI)

Location: The spinal accessory nerve enters the deep surface of the SCM in the upper third and emerges at the posterior border near the junction of the upper and middle thirds (Erb's point region).

Risk: At the SUPERIOR (mastoid) release in a bipolar procedure, aggressive dissection high on the muscle risks CN XI injury (trapezius weakness, shoulder droop). Stay close to the mastoid bone and divide only the tendinous insertion.

Facial Nerve - Marginal Mandibular Branch

Location: The marginal mandibular branch of the facial nerve runs near the angle of the mandible, superficial and superior to the upper SCM.

Risk: A superior incision placed too high or too anterior, or vigorous retraction near the mandibular angle, can injure this branch (lower-lip asymmetry). Keep the superior incision low, transverse and within a skin crease.

Excluding Non-Muscular Torticollis

Why it matters: Operating on a non-muscular torticollis is a never event. Ocular torticollis (corrects when lying or eyes closed), Klippel-Feil/vertebral anomalies (short neck, low hairline, restricted painless rotation), atlantoaxial rotatory subluxation (acute, painful, 'cock-robin'), posterior fossa tumour and Sandifer syndrome (reflux) all mimic CMT.

The fix: A torticollis without a tight fibrotic SCM band, without head tilt toward the tight side, or that fails to respond to stretching demands imaging (cervical spine, often MRI brain/spine) before any surgery is contemplated.

Mnemonic

TORTICOLLISTORTICOLLIS - Assessing the Infant

Mnemonic

RELEASERELEASE - Operative Principles of SCM Release

Aetiology and Pathology

Congenital muscular torticollis (CMT) is the most common cause of torticollis in infancy. The primary lesion is fibrosis and contracture of the sternocleidomastoid muscle. Several theories exist for the cause:

  • Intrauterine crowding / packaging - abnormal foetal position, often supported by the association with breech presentation, primigravida and oligohydramnios
  • Compartment syndrome / ischaemia - localised ischaemia of the SCM leading to fibrosis (consistent with the histology of the sternomastoid tumour)
  • Birth trauma - historically proposed, but CMT also occurs after uncomplicated and caesarean deliveries
  • Hereditary / connective tissue factors - a minority show a familial pattern

The Sternomastoid Tumour (Pseudotumour of Infancy)

  • A firm, mobile, fusiform swelling within the SCM belly, typically appearing in the first few weeks of life and usually resolving over months
  • Histology shows fibroblast proliferation and collagen deposition replacing muscle - it is NOT a neoplasm
  • Its presence is associated with a tighter contracture and a slightly higher rate of needing surgery, but most still resolve with physiotherapy

Clinical Assessment

The Classic Posture

  • The contracted SCM shortens the distance between the mastoid process and the sternoclavicular joint
  • This produces a head TILT toward the affected (tight) side and chin ROTATION AWAY to the opposite side
  • Operate on the side the head is tilted TOWARD (the short, tight muscle)

Examination

  • Palpate the SCM for a fusiform pseudotumour or a tight, cord-like band
  • Measure passive cervical rotation and lateral flexion; quantify the deficit compared with the normal side
  • Inspect for plagiocephaly (flattening of the skull) and facial asymmetry (hemihypoplasia of the affected side)
  • Examine the hips in every infant - DDH co-exists in a clinically important proportion

Associations to Screen For

  • Developmental dysplasia of the hip (DDH) - the most important; examine (Ortolani/Barlow) and image (ultrasound under 6 months, radiograph after)
  • Metatarsus adductus and other foot deformities
  • Plagiocephaly and facial hemihypoplasia - markers of long-standing deformity

Differential Diagnosis - Exclude Before Calling it Muscular

Non-Muscular Torticollis - Features that Demand Imaging

Clinical Pearl

Examiner cue: 'A torticollis without a tight SCM band, without the typical tilt-toward / chin-away posture, or one that does not improve at all with stretching, is not CMT until proven otherwise. I would image the cervical spine and consider MRI before ever planning a muscle release.'


Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 4-week-old infant is referred with a head tilt. The mother noticed a firm lump in the side of the neck. On examination the head is tilted to the right and the chin points to the left, with a firm fusiform swelling in the right sternocleidomastoid. How do you assess and manage this child?"

PRACTICAL APPROACH
This is the classic presentation of congenital muscular torticollis with a sternomastoid tumour (pseudotumour of infancy). The head tilts toward the tight muscle - here the right SCM - and the chin rotates away to the left. **History**: I would ask about the birth (breech presentation, primigravida, difficult or instrumented delivery, oligohydramnios), when the tilt and lump were first noticed, and whether the posture is fixed or variable. **Examination**: I would confirm the typical tilt-toward / chin-away posture, palpate the SCM for the firm fusiform pseudotumour and a tight band, and measure the passive rotation and lateral flexion deficit. I would inspect for early plagiocephaly and facial asymmetry. Critically, I would examine the hips with Ortolani and Barlow tests because DDH is the most important association. **Investigations**: I would arrange a hip ultrasound to exclude DDH (appropriate under 6 months of age). If any feature is atypical for muscular torticollis - no tight band, wrong direction of tilt, neurological signs, or failure to improve - I would image the cervical spine and consider MRI to exclude non-muscular causes. **Management**: First-line treatment is early physiotherapy and a caregiver stretching and positioning programme - gentle lateral flexion away from the tight side and rotation toward it, tummy time, and environmental modification. Started this early, conservative treatment resolves the great majority of cases. I would reassure the parents that the lump usually resolves and that surgery is rarely needed. I would arrange follow-up to monitor range of motion, facial symmetry and the hip result.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 3-year-old child has a persistent right-sided congenital muscular torticollis. Despite a supervised stretching programme since infancy, there is a fixed head tilt with a tight palpable band and a rotation deficit of about 25 degrees, plus early facial asymmetry. You decide to operate. Talk me through your surgical plan and the structures you must protect."

PRACTICAL APPROACH
This child has failed conservative treatment with a significant fixed deficit and a tight band, so surgical release of the right SCM is indicated. Before operating I would make absolutely sure a non-muscular cause has been excluded - there is a discrete fibrotic band and the typical posture, but I would have cervical spine imaging available. **Procedure choice**: For a moderate contracture I would start with a unipolar distal release of both heads. Given the age and the early facial asymmetry, I am prepared to convert to a bipolar release (adding a proximal mastoid release) if a residual deficit remains after the distal release. **Positioning**: Supine with a shoulder roll, neck extended and head rotated to the left to put the right SCM on stretch. **Incision**: A low transverse incision in a skin crease about two finger-breadths above the clavicle, over the two heads - kept low to avoid the marginal mandibular branch of the facial nerve. **Technique**: Through platysma I identify the sternal and clavicular heads. I pass a protected clamp deep to each head, staying on the muscle to shield the deep structures, then divide both heads completely under direct vision, excising a short segment so the ends retract. I divide any residual tight deep fascial bands. I then take the head into over-correction and confirm full rotation and lateral flexion. **Structures I must protect**: - At the inferior release - the carotid sheath (carotid artery, internal jugular vein, vagus) deep and medial, and the external/anterior jugular veins crossing the field; I never dissect deep to the muscle and I control the veins - If I add a proximal release - the spinal accessory nerve entering the deep upper SCM (stay on the tendinous insertion close to the mastoid), the marginal mandibular branch of the facial nerve (keep the incision low), and the great auricular nerve **Post-operatively** I would maintain the corrected position with a stretching programme and bracing/positioning to prevent recurrence, and counsel that the established facial asymmetry may only partly remodel at this age.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 2-year-old is referred with a head tilt that the GP has labelled 'torticollis'. The neck moves through a full painless range, there is no palpable tight band, and the tilt seems to vary - it disappears when the child lies down. What is your approach?"

PRACTICAL APPROACH
The features described are atypical for congenital muscular torticollis and are a red flag for a non-muscular cause. CMT has a fixed contracture with a tight, often palpable SCM band and a restricted range; a torticollis that has full painless movement, no tight band, and that varies or corrects on lying down is not muscular until proven otherwise. **My approach is to slow down and exclude the dangerous and treatable mimics before considering any neck surgery:** - **Ocular torticollis** - a compensatory tilt for a vertical squint or other strabismus; it characteristically corrects when lying down or with the eyes closed. I would arrange an ophthalmology assessment. - **Cervical spine anomaly (Klippel-Feil, hemivertebrae)** - I would examine for a short neck and low hairline and obtain cervical spine radiographs; if abnormal, screen for associated renal and cardiac anomalies. - **Atlantoaxial rotatory subluxation** - usually acute and painful after a URTI or ENT surgery; a dynamic CT of C1-C2 if suspected. - **Posterior fossa tumour** - a progressive tilt with any neurological sign, headache or vomiting mandates urgent MRI of the brain. - **Sandifer syndrome** - intermittent dystonic posturing related to gastro-oesophageal reflux; assess feeding and reflux. - **Benign paroxysmal torticollis** - recurrent self-limiting episodes, often migraine-related. **Investigations**: cervical spine radiographs as a baseline, and a low threshold for MRI of the brain and cervical spine given the atypical, variable presentation. I would not contemplate any SCM release in this child - operating on a non-muscular torticollis is a never event.

Congenital Muscular Torticollis - SCM Release - Exam Day Summary

Clinical summary

Evidence Base

The clinical presentation and outcome of treatment of congenital muscular torticollis in infants - a study of 1,086 cases

Level II
Cheng JC, Tang SP, Chen TM, Wong MW, Wong EM • Journal of Pediatric Surgery
Clinical Implication: Confirms that early manual stretching resolves the great majority of CMT and that surgery is needed in only a small minority - and that the sternomastoid tumour subgroup carries the strongest association with hip dysplasia, justifying routine hip screening.
Verify on PubMed (PMID 10917303)

Clinical determinants of the outcome of manual stretching in the treatment of congenital muscular torticollis in infants - a prospective study of 821 cases

Level I
Cheng JC, Wong MW, Tang SP, Chen TM, Shum SL, Wong EM • Journal of Bone and Joint Surgery (American)
Clinical Implication: The evidence basis for the threshold used in this guide - reserve surgery for persistent deficit greater than 15 degrees after a sustained stretching programme, in a child with a definite contracture.
Verify on PubMed (PMID 11379737)

Physical Therapy Management of Congenital Muscular Torticollis: A 2018 Evidence-Based Clinical Practice Guideline

Guideline
Kaplan SL, Coulter C, Sargent B (APTA Academy of Pediatric Physical Therapy) • Pediatric Physical Therapy
Clinical Implication: The current international reference standard for non-operative CMT management; surgery is positioned only after a structured physiotherapy pathway has failed.
Verify on PubMed (PMID 30277962)

Ultrasonographic study of the coexistence of muscular torticollis and dysplasia of the hip

Level III
Tien YC, Su JY, Lin GT, Lin SY • Journal of Pediatric Orthopaedics
Clinical Implication: Quantifies why every infant with CMT must have the hips examined and imaged - a clinically important proportion harbour treatable hip dysplasia.
Verify on PubMed (PMID 11371818)

Change of craniofacial deformity after sternocleidomastoid muscle release in pediatric patients with congenital muscular torticollis

Level III
Lee JK, Moon HJ, Park MS, Yoo WJ, Choi IH, Cho TJ • Journal of Bone and Joint Surgery (American)
Clinical Implication: Provides the evidence for counselling families that early release maximises facial remodelling, whereas late surgery corrects motion but the established facial asymmetry remodels less completely.
Verify on PubMed (PMID 22760394)

References

  1. Cheng JC, Tang SP, Chen TM, Wong MW, Wong EM (2000). The clinical presentation and outcome of treatment of congenital muscular torticollis in infants - a study of 1,086 cases. J Pediatr Surg 35(7):1091-6. PMID 10917303. — Large prospective cohort defining the three clinical subgroups, the sternomastoid tumour subtype, the hip-dysplasia association and excellent outcomes with early manual stretching (91.1% good/excellent, 5.1% needing surgery).

  2. Cheng JC, Wong MW, Tang SP, Chen TM, Shum SL, Wong EM (2001). Clinical determinants of the outcome of manual stretching in the treatment of congenital muscular torticollis in infants. A prospective study of eight hundred and twenty-one cases. J Bone Joint Surg Am 83(5):679-87. PMID 11379737. — Prospective study identifying prognostic factors for conservative management and defining the over-15-degree deficit surgical threshold.

  3. Kaplan SL, Coulter C, Sargent B (2018). Physical Therapy Management of Congenital Muscular Torticollis: A 2018 Evidence-Based Clinical Practice Guideline From the APTA Academy of Pediatric Physical Therapy. Pediatr Phys Ther 30(4):240-90. PMID 30277962. — Evidence-based clinical practice guideline for the non-operative management of CMT.

  4. Tien YC, Su JY, Lin GT, Lin SY (2001). Ultrasonographic study of the coexistence of muscular torticollis and dysplasia of the hip. J Pediatr Orthop 21(3):343-7. PMID 11371818. — Documents a 17% coexistence (8.5% requiring treatment) of CMT and developmental dysplasia of the hip, supporting routine hip screening.

  5. Lee JK, Moon HJ, Park MS, Yoo WJ, Choi IH, Cho TJ (2012). Change of craniofacial deformity after sternocleidomastoid muscle release in pediatric patients with congenital muscular torticollis. J Bone Joint Surg Am 94(13):e93. PMID 22760394. — Demonstrates greater craniofacial remodelling when release is performed before 5 years of age, with most change in the first postoperative year.

  6. Ferkel RD, Westin GW, Dawson EG, Oppenheim WL (1983). Muscular torticollis. A modified surgical approach. J Bone Joint Surg Am 65(7):894-900. PMID 6885869. — Describes the modified bipolar release with Z-plasty for resistant/older cases (92% good/excellent versus inferior results with other operations).