Gokce Mik and Denis S. Drummond
DEFINITION
The sternocleidomastoid (SCM) muscle is a major muscle of the neck that laterally flexes and rotates the head.
The term torticollis comes from the Latin words tortus (twisted) and collum (neck). It refers to a clinical deformity where the head tilts in one direction and the neck rotates to the opposite side involuntarily.
Congenital muscular torticollis (CMT) associated with a contracture of the SCM muscle is the most common etiology of torticollis in infants.
CMT is the third most common congenital deformity, next to developmental dysplasia of the hip and congenital clubfoot. The incidence of CMT ranges from 0.4% to 1.3%.3,6,10
Shortening and contracture of the SCM muscle results in tightness that gives the typical clinical appearance, which is detected at birth or shortly thereafter.
Cheng et al3 subdivided the CMT patients into three groups:
Clinically palpable sternomastoid “tumor” or pseudotumor
Muscular torticollis group without palpable or visible tumor but with clinical thickening or tightness of the SCM on the affected side
All the clinical features of torticollis with neither a palpable mass nor tightness of the SCM muscle
ANATOMY
On each side, the SCM muscle passes obliquely across the side of the neck and divides the neck into anterior and posterior triangles.
It originates from two heads.
Sternal head: superior and anterior surface of manubrium sterni.
Clavicular head: superior surface of medial third of clavicle. With the two heads combining, the muscle ascends laterally and posteriorly to insert in the mastoid process of the temporal bone.
The functions of sternocleidomastoid are multiple.
With unilateral contraction, it:
Flexes the head and cervical spine ipsilaterally
Laterally rotates the head to the contralateral side
With bilateral contraction, it.
Protracts the head
Extends the incompletely extended cervical spine
The SCM is innervated by the.
Spinal accessory nerve (XI)
Ventral ramus of second cervical nerve (C2)
The spinal accessory nerve penetrates the deep surface of the SCM muscle, giving off a branch that supplies it. It passes to the posterior aspect of the SCM deep to Erb's point.
Erb's point is located roughly in the middle of the posterior border of the SCM muscle. At this point, the anterior branch of the greater auricular nerve crosses the SCM.
The external jugular vein is located anterior to the SCM muscle at the proximal part. It crosses the SCM muscle obliquely at its midpoint and ends at the subclavian vein posteroinferior to the SCM muscle.
The SCM protects the carotid artery and internal jugular vein, both of which lie deep to it.
The clavicular origin of the SCM muscle can vary in size. In some cases, the width of the clavicular attachment may extend to the midpoint of the clavicle.
The anatomy of the SCM muscle and important surrounding structures is shown in FIGURE 1.
PATHOGENESIS
The most common etiology of CMT in infants is contracture or shortening of the SCM muscle.
Infants with CMT most often have a history of difficult or traumatic delivery.
Davids et al7 reported that the position of the head and neck in utero or during labor or delivery can lead to local trauma to the SCM muscle. This is the only muscle in the SCM muscle compartment demonstrated by cadaver studies.
Progressive fibrosis and contracture of the SCM muscle may be the sequelae of an intrauterine or perinatal compartment syndrome.7
FIG 1 • Anatomy of sternocleidomastoid (SCM) muscle and important surrounding structures. Note the course of the external jugular vein and greater auricular nerve; the carotid artery and internal jugular vein lie deep to the SCM muscle.
CMT may occur in association with oligohydramnios, multiple births, first-born children, and developmental dysplasia of the hip (DDH).
These data support the theory of intrauterine restricted fetal motion and malpositioning of the head and neck. These conditions may be associated with more difficult and traumatic deliveries.
However, CMT found in the infants who are delivered by cesarean section is not consistent with the theory of birth trauma.
The data that show 20% coexistence of developmental dysplasia of the hip support the theory of intrauterine malposition and crowding.9
About 50% of patients with CMT are born with a clinically palpable SCM tumor.1,5 This tumor or pseudotumor is believed to be a developing hematoma that undergoes subsequent fibrosis. This could result from either birth trauma or intrauterine malposition.
Electron microscopy studies revealed that the existence of myoblasts in the interstitium of the mass at different stages of differentiation and degeneration might have a significant bearing on the pathogenesis of torticollis.13
Tang et al13 explained the success of conservative management (stretching exercises) with the presence of myoblast cells besides fibroblast cells.
In vitro, myoblasts could be mechanically stimulated to undergo both hypertrophy and hyperplasia by intermittent stretching and relaxation.
The pathogenesis of the torticollis resulting from pathologies other than CMT is affiliated with other conditions or syndromes.
NATURAL HISTORY
Diagnosis of CMT is usually made at or near birth. Other causes of torticollis generally present later (4 months to 1 year).
A mass (SCM tumor) or fullness in the SCM muscle usually exists within a few weeks or months after delivery.
Typically, the mass decreases in size and disappears between 6 and 12 months of age.
If it remains untreated, contraction and sometimes a fibrous bundle can occur in the muscle.
Flexion and rotation deformity of the neck begins in infancy.
Typically the head turns toward the involved side and the chin points to the opposite shoulder.
Plagiocephaly and facial asymmetry may be present early on; they increase with time.
In persistent cases, deformity progresses and becomes inflexible.
Flattening of the skull and facial bones can develop on the affected or normal side depending on the sleeping position of the child.
If the child remains untreated until 5 to 7 years of age, contraction of the neck with limited motion becomes resistant to correction. The deformity of the cranium and facial bones also becomes less amenable to spontaneous correction.
Formation of a lateral band is mostly responsible for limited neck mobility.
In older children with persistent deformity, radiographic abnormalities can also occur; they include asymmetry of the articular facets of the axis, tilt of the odontoid process to the side of the torticollis, and possibly cervicothoracic scoliosis.2,12
PATIENT HISTORY AND PHYSICAL FINDINGS
A complete history and physical examination should be done in newborns with torticollis.
The incidence of the breech presentation and birth trauma in children with CMT is higher than the general population.
There is known coexistence of DDH with torticollis.
The reported incidence of DDH with CMT varies from 8% to 20%.9,15
A clinical examination of the hip and ultrasonography screening are thus required for children with CMT.
A previous belief that CMT was associated with metatarsus adductus and clubfoot is not supported by the literature.
Typically, children with CMT hold their head laterally flexed to the affected side and rotate their face to the opposite side.
Range of neck movement can initially be normal in infants with CMT. Later, the typical deformity can usually be observed. This gradually progresses as the muscle contracture becomes tighter.
Any degree of restriction should be noted during the examination.
The facial bones and cranium are observed for asymmetry. Any flattening of the skull bones is also noted.
With palpation, a nontender, soft mass of 1 to 2 cm is occasionally found in the lower or middle third of the SCM muscle. With time, the mass changes to a fibrous bundle, and the SCM tendon can then be identified as a tight band that resists correction (FIG 2).
FIG 2 • A nontender, soft mass of 1 to 2 cm can be found in the lower or middle third of the sternocleidomastoid (SCM) muscle within weeks or a few months after delivery. At later ages (usually after 6 to 12 months of age), the mass changes to a fibrous bundle and the SCM tendon then can be identified as a tight band.
The flexible deformity seen in the early stage can be corrected by gentle stretching.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Radiographs
Standard cervical spine anteroposterior and lateral views and open-mouth odontoid views are obtained to rule out bony abnormalities such as atlantoaxial instability or fixation, cervical fusion, cervical scoliosis, and odontoid anomalies.
At the later phases of the developing deformity, radiographic abnormalities such as asymmetry of the articular facets of the axis, tilt of the odontoid process to the side of the torticollis, and sometimes cervicothoracic scoliosis may be observed.2,12
Ultrasound examination should be performed in children with a palpable SCM mass to demonstrate the fibrotic lesion within the SCM muscle and to differentiate the mass from other pathologies in the neck such as neoplasms, cysts, and vascular malformations.
In a recent study Tang et al14 presented their observations with the use of ultrasound for the long-term follow-up of CMT. They noticed that CMT is a polymorphic and dynamic condition rather than a fixed presentation. The alterations of the fibrosis in muscle can affect the type of treatment.
Hip ultrasonography should be routinely done in patients born with CMT.
There is a relatively high incidence of coexistence between CMT and DDH.
Some investigators have advised MRI to evaluate the muscle for thickening and fibrosis; however, it does not provide additional information. Further, for infants, MRI requires a general anesthetic, with its associated risks.
If a posterior fossa tumor is suspected, MRI is indicated.
DIFFERENTIAL DIAGNOSIS
Ophthalmologic torticollis occurs with oculomotor imbalance, which is usually observed after the development of focusing skills (3 months). Ophthalmologic torticollis is caused by a weakness of one of the oculomotor muscles of the eye (typically the superior oblique). This causes a strabismus that can be observed if the head tilt is manually corrected. (This maneuver is useful in providing a diagnosis.) Other causes are strabismus and nystagmus.
Neurologic causes such as the postural head tilt seen with posterior fossa tumors must be ruled out.
Nucci et al,11 in a multidisciplinary study, reported 25 ocular and 4 neurologic causes in 65 children with abnormal head posture.
About 10% of posterior fossa tumors initially present with torticollis.
The other orthopaedic causes of torticollis include congenital cervical vertebral anomalies (scoliosis, Klippel-Feil syndrome) and atlantoaxial rotational instability.
Grissel syndrome: torticollis associated with retropharyngeal abscess or post-tonsillectomy status.
Neck abscess or inflammatory disorders
Sandifer syndrome (reflux)
Neurologic
Posterior fossa tumors
Dystonia
NONOPERATIVE MANAGEMENT
The initial treatment of CMT is nonoperative and is successful in the vast majority of infants by 1 year of age.
A program of gentle stretching exercises should include flexion–extension, lateral bending away from the involved side and rotation toward it.
Stretching exercises can be done by a physical therapist or by the parents with a home program.
In our experience, a supervised home program monitored by a physical therapist is the most successful method.
Manual stretching should be continued until full neck rotation is achieved.
In children 1 year of age or less, the plagiocephaly and facial asymmetry usually remodel spontaneously after the child regains full range of motion of the neck.
Cervical orthoses may be an adjunct and support for children whose lateral head tilt does not resolve with exercises, or for older children who no longer tolerate stretching.
The duration of the conservative treatment could be longer in children who have SCM tumor at initial presentation.
The success rate of manual stretching in these patients is lower than those without a SCM tumor.4
Surgery is recommended for recalcitrant deformity when adequate correction is not achieved by 1 year of age.
Children who present after 1 year of age with or without previous treatment are candidates for surgery if they have:
Significant head tilt with tight band or contracture of the SCM muscle
Limitation of passive head rotation and lateral flexion by more than 10 to 15 degrees
SURGICAL MANAGEMENT
Surgical intervention is indicated for children who have not responded to nonoperative treatment applied for a minimum of 6 months and for children who present with a significant deformity after 1 year of age.
The hypothesis is that the sooner correction of the torticollis is achieved, the better the chance for spontaneous correction of the plagiocephaly and facial asymmetry.
If there is doubt about the diagnosis of CMT, surgery is contraindicated until a workup has been completed because there could be an underlying disorder causing torticollis, such as ocular or neurogenic pathologies.
The operative techniques described for CMT are based on release or lengthening of the tight and shortened SCM muscle.
Most commonly preferred procedures include unipolar release, bipolar release with or without Z-plasty lengthening of the sternal head, and the extended procedure for older children and resistant cases.
Open, percutaneous, and endoscopic techniques have been described for these procedures. We have no experience with endoscopic technique, and we prefer the open approach.
Authors' Preferred Treatment
For infants, a home stretching program is taught and supervised by a physical therapist for 6 months.
In children with appropriate surgical indications, bipolar release (with or without Z-plasty lengthening) is carried out.
In older children with significant deformity, a bipolar release is the first step. Z-plasty may be appropriate in the older children to provide a symmetric appearance postoperatively.
If satisfactory correction is not demonstrated at intraoperative examination, the distal dissection is extended to permit release of the clavicular head and remaining bands.
Preoperative Planning
Cervical spine radiographs should be reviewed before surgery to look for bony anomalies or cervical scoliosis.
In fixed deformities, positioning of the head can be difficult for the anesthesiologist. Flexible fiberoptic intubation should then be considered.
The ear is taped anteriorly and hair around the mastoid process is shaved.
Positioning
The procedure is performed under general anesthesia in the supine position. A sandbag is placed to elevate the shoulder on the affected side.
The endotracheal tube should be kept at the unaffected side so as not to interfere with the operative field.
Draping should allow the correction to be evaluated by bending the neck. This determines the adequacy of the release intraoperatively.
The shoulder draping should permit the anesthesiologist to hold the shoulder, which can maximize tension during this test.
The neck is bent toward the unaffected side and the head is rotated to the affected side so that the SCM muscle is kept under tension and the origin and insertion can be clearly identified.
TECHNIQUES
INCISION AND DISSECTION
For the release of the distal pole of the SCM muscle, a transverse, 3to 4-cm-long incision is made 1 cm superior to the clavicle and between the two heads of the SCM muscle (TECH FIG 1).
The subcutaneous tissue and platysma muscle are divided in the line of incision and the tendon sheaths of the clavicular and sternal heads are exposed.
For the proximal pole exposure, a 2to 3-cm horizontal incision is made just distal to the tip of the mastoid process.
The dissection is carried deeper until the periosteum of the mastoid process is exposed. The insertion of the muscle is then exposed subperiosteally.
TECH FIG 1 • Proximal and distal incisions (dotted lines).
DISTAL UNIPOLAR RELEASE
Distal unipolar release includes the release of the sternal and sometimes the clavicular heads of the SCM muscle. It may be enough for mild deformities.
A transverse incision is placed parallel and 1 cm proximal to the clavicle between the clavicular and sternal heads of the SCM.
An incision that overlies over the clavicle may result in a hypertrophic scar. A higher incision may jeopardize the external jugular vein and may also lead to an unsightly scar.
Two heads of the SCM muscle are identified as described.
Surrounding fascia is cleared and the sternal head or both heads are undermined with a curved clamp.
The muscles are elevated with the help of a clamp and divided using electrocautery (TECH FIG 2).
Alternatively, the sternal head can be lengthened by Z-plasty.
TECH FIG 2 • The origin of the muscle is elevated with the help of a clamp and divided using electrocautery. About 5 to 10 mm of muscle–tendon segment is divided to prevent further contracture and fibrous adhesions.
About 5 to 10 mm of the muscle–tendon segment is excised to prevent further contracture and fibrous adhesions.
The adequacy of the release is checked by bending the neck to the contralateral side and rotating it to the ipsilateral side while palpating the area with a fingertip to identify any remaining tight bands. They are completely released.
The incision is closed with subcuticular suture after careful hemostasis.
BIPOLAR RELEASE (AUTHORS' PREFERENCE)
Bipolar release includes the release of the mastoid insertion of the SCM muscle along with the distal release just described.
The procedure starts with a distal incision.
The two heads of the SCM muscle are identified. After undermining the tendons, the curved clamp is left underneath them.
The curved clamp is left lying superficial to the wound but deep to the tendon. While applying enough tension, ease the proximal exposure and identification of the insertion. The wound is then covered with a moist sponge.
With the tension applied by the clamp under the tendon at the distal exposure, a safe identification of the origin has been simplified. Further, the limited exposure avoids the important anatomy (TECH FIG 3A).
Attention is directed to the proximal insertion and the incision is placed as described before.
The insertion of the muscle is identified anteriorly and posteriorly. Dissection starts subperiosteally from the mastoid process to avoid the facial nerve anteriorly and the anterior branch of the great auricular nerve inferiorly.
A curved clamp is passed just deep to the tendon to elevate it so it can be sectioned completely (TECH FIG 3B).
There is no need to resect a segment of muscle at the proximal part.
After the proximal release is performed, attention is then directed back to the distal incision and distal release is completed as described before.
Release of the clavicular head with the lengthening of the sternal head by Z-plasty may be appropriate in older children to provide a symmetrical appearance postoperatively (TECH FIG 3C).8
The neck is rotated and bent with the help of the anesthesia team while checking the area with a fingertip to identify any remaining tight bands; they are completely released.
Both surgical areas are checked to identify if any remaining tight bands or fascial structures are impeding full correction. They are divided carefully.
Subcutaneous and subcuticular skin closure is then performed after hemostasis.
TECH FIG 3 • A. With tension applied to the tendon at the distal exposure, a safe identification of the origin has been simplified. Further, the limited exposure avoids the important anatomy. B. A curved clamp is passed just deep to the tendon to elevate it for complete sectioning. C. Bipolar release with the lengthening of the sternal head by Z-plasty. (C: Modified from Ferkel RD, Westin GW, Dawson EG, et al. Muscular torticollis: a modified approach. J Bone Joint Surg Am 1983;65:894–890.)
POSTOPERATIVE CARE
Postoperative management includes immobilization of the head and neck in a slightly overcorrected position with a thermoplastic custom-made brace or pinless halo for 3 weeks (FIG 3).
The purpose of the brace immobilization is to avoid a habitual posture followed by postoperative scarring. It might also help to reprogram the corrected posture as a norm for the child.
The brace is removed in 3 weeks and passive stretching is recommended as well as active strengthening exercises.
Exercises are continued at home for 3 to 6 months.
OUTCOMES
Early conservative management is successful in over 90% of children with CMT who are younger than 1 year.3,4,6
In resistant cases there is still controversy between unipolar and bipolar release.
Cheng et al3–5 reported excellent results in children operated on at age 6 months to 2 years with unipolar release.
Canale et al1 found better results after bipolar release, although the difference was not statistically significant.
Wirth et al16 reported satisfactory results in 48 of 55 patients who had undergone bipolar release, with low recurrence rates (1.8%).
FIG 3 • Pinless halo device for postoperative management.
Ferkel et al8 described a modified bipolar release technique that includes release of the mastoid and clavicular attachments of the SCM muscle and Z-plasty lengthening on the sternal origin to maintain a V contour of the neck distally for cosmesis. They reported 92% satisfactory results with this technique.
We have had one case of recurrence with unipolar release and none with bipolar release in about 50 cases. There have been no wound problems, hypertrophic scarring, or neurovascular complications.
COMPLICATIONS
Wound breakdown
Hematoma
Residual lateral band
Neurovascular damag.
Spinal accessory nerve
Anterior branch of the great auricular nerve
External jugular vein
Carotid artery
Hypertrophic scar
REFERENCES
· Canale ST, Griffin DW, Hubbard CN. Congenital muscular torticollis: a long-term follow-up. J Bone Joint Surg Am 1982;64:810–816.
· Chen CE, Ko JY. Surgical treatment of muscular torticollis for patients above 6 years of age. Arch Orthop Trauma Surg 2000;120: 149–151.
· Cheng JCY, Tang SP, Chen TMK, et al. The clinical presentation and outcomes of treatment of congenital muscular torticollis in infants: a study of 1086 cases. J Pediatr Surg 2000;35:1091–1095.
· Cheng JCY, Wong MWN, Tang SP, et al. Clinical determinants of the outcome of manual stretching in the treatment of congenital muscular torticollis in infants. J Bone Joint Surg Am 2001;83:679–687.
· Cheng JCY, Tang SP, Chen TMK. Sternocleidomastoid pseudotumor and congenital muscular torticollis in infants: a prospective study of 510 cases. J Pediatr 1999;134:712–716.
· Coventry MB, Harris LE. Congenital muscular torticollis in infancy: some observations regarding treatment. J Bone Joint Surg Am 1959;41:815–822.
· Davids JR, Wenger DR, Mubarak SJ. Congenital muscular torticollis: sequela of intrauterine or perinatal compartment syndrome. J Pediatr Orthop 1993;13:141–147.
· Ferkel RD, Westin GW, Dawson EG, et al. Muscular torticollis: a modified approach. J Bone Joint Surg Am 1983;65:894–900.
· Hummer CD, Macewen GD. The coexistence of torticollis and congenital dysplasia of the hip. J Bone Joint Surg Am 1972;54:1255–1256.
· Ling CM, Low YS. Sternocleidomastoid tumor and muscular torticollis. Clin Orthop Relat Res 1972;86:144–150.
· Nucci P, Kushner BJ, Serafino M, et al. A multi-disciplinary study of the ocular, orthopaedic, and neurologic causes of abnormal head postures in children. Am J Opthalmol 2005;140:65–68.
· Oh I, Nowacek CJ. Surgical release of congenital torticollis in adults. Clin Othop Relat Res 1978;131:141–145.
· Tang S, Liu Z, Quan X, et al. Sternocleidomastoid pseudotumor of infants and congenital muscular torticollis: fine-structure research. J Pediatr Orthop 1998;18:214–218.
· Tang SF, Hsu KH, Wong AM, et al. Longitudinal follow-up study of ultrasonography in congenital muscular torticollis. Clin Orthop Relat Res 2002;403:179–185.
· Walsh JJ, Morrissy RT. Torticollis and hip dislocation. J Pediatr Orthop 1998;18:219–221.
· Wirth CJ, Hagena FW, Wuelker N, et al. Biterminal tenotomy for the treatment of the muscular torticollis. J Bone Joint Surg Am 1992;74:427–434.