Release of the Sternocleidomastoid Muscle

 

 

 

 

 

DEFINITION

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 sternocleidomastoid (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 (DDH) and congenital clubfoot. The incidence of CMT ranges from 0.4% to 1.3%.4, 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 al4 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 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.

 

 

It inserts on the lateral aspect of the mastoid process. The functions of SCM 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 following:

 

 

Spinal accessory nerve (XI)

 

Ventral ramus of second cervical nerve (C2)

 

Erb point is located roughly in the middle of the posterior border of the SCM muscle. At this point, the anterior branch of the great auricular nerve crosses the SCM.

 

The spinal accessory nerve penetrates the deep surface of the SCM muscle, giving off a branch that supplies it. It passes deep to Erb point at the posterior aspect of 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 anatomy of the SCM muscle and important surrounding structures is shown in FIG 1.

PATHOGENESIS

 

The etiology of CMT in infants is contracture or shortening of the SCM muscle.

 

 

 

FIG 1 • Anatomy of 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.

 

 

P.695

 

Infants with CMT may 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.

 

Progressive fibrosis and contracture of the SCM muscle may be the sequelae of an intrauterine or perinatal compartment syndrome.7

 

CMT may occur in association with oligohydramnios, multiple births, firstborn children, and DDH.9

 

 

These associated conditions support the theory that CMT is related to restricted fetal motion and malpositioning of the head and neck. These conditions may also be associated with more difficult and traumatic deliveries.

 

About 50% of patients with CMT are born with a clinically palpable SCM mass (pseudotumor).1, 3 This pseudotumor is believed to be a hematoma that undergoes subsequent fibrosis and may result from either birth trauma or intrauterine malposition.

 

Torticollis may also result from many other diseases such as ophthalmologic problems (eg, Duane syndrome), congenital cervical anomalies, and neurologic problems (eg, posterior fossa tumors).

 

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 presents within a few weeks or months after delivery.

 

 

Typically, the mass decreases in size and disappears between 6 and 12 months of age. If untreated, contraction and fibrosis of the muscle can occur.

 

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.

 

Flattening of the skull and facial bones can develop on the affected or normal side depending on the sleeping position of the child.

 

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

 

 

 

FIG 2 • A nontender, soft mass of 1 to 2 cm can be found in the lower or middle third of the 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.

 

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, 14, 15

 

A clinical examination of the hip and ultrasonography screening are thus warranted 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 rotated to the opposite side.

 

Neck range of motion can initially be normal in infants with CMT. This gradually decreases as the muscle contracture becomes tighter. Later, the typical deformity can usually be observed.

 

 

Any restriction of neck motion should be noted during the examination.

 

The facial bones and cranium are observed for asymmetry. Any flattening of the skull bones should also be noted.

 

With palpation, a nontender, soft mass 1 to 2 cm in diameter may be found in the lower or middle third of the SCM muscle. With time, this mass changes to a fibrous bundle, and the SCM tendon can then be identified as a tight band that resists correction (FIG 2).

 

The flexible deformity seen in the early stage can be corrected by gentle stretching.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Radiographs

 

 

Standard cervical spine anteroposterior (AP) and lateral views and open mouth odontoid views can be obtained to rule out bony abnormalities such as atlantoaxial rotary subluxation, cervical fusion, cervical scoliosis, and odontoid anomalies.

 

In older children, 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

 

 

P.696

 

Ultrasound examination in children with a palpable SCM mass will demonstrate the fibrotic lesion within the SCM muscle and differentiate the mass from other pathologies in the neck such as neoplasms, cysts, and vascular malformations.

 

 

In a recent study, Tang et al13 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 imaging should be routinely done in patients born with CMT because there is a high incidence of coexistence of DDH with CMT.9, 14

 

Patients younger than 6 months of age should have a hip ultrasound performed; children older than 6 months should have an AP pelvis radiograph performed.

 

Some investigators have advised magnetic resonance imaging (MRI) to evaluate the SCM muscle for thickening and fibrosis; however, it does not provide additional information. Furthermore, for infants, MRI requires a general anesthetic, with its associated risks.

 

 

If a posterior fossa tumor is suspected, MRI is indicated.

 

 

DIFFERENTIAL DIAGNOSIS

Nucci et al,11 in a multidisciplinary study, reported 25 ocular and 4 neurologic causes in 65 children with abnormal head posture.

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, nystagmus, and paralysis of the sixth cranial nerve resulting in paralysis of the lateral rectus muscle of the eye (Duane syndrome).

Neurologic causes such as posterior fossa tumors must be ruled out. About 10% of posterior fossa tumors initially present with torticollis.

Postural head tilt may be seen with posterior fossa tumors and this may mimic recurrent or relapsed

CMT.

Other orthopaedic causes of torticollis include congenital cervical vertebral anomalies (scoliosis, Klippel-Feil syndrome) and atlantoaxial rotational subluxation.

Grisel syndrome is torticollis secondary to neck inflammation and is associated with retropharyngeal abscess or post-tonsillectomy status.

Sandifer syndrome (neck posturing secondary to reflux) Other neurologic diseases such as dystonia

 

NONOPERATIVE MANAGEMENT

 

The initial treatment of CMT is nonoperative and is successful in the vast majority of infants when treatment is initiated before 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 has been successful.

 

Manual stretching should be continued until full neck rotation is achieved.

 

In children 1 year of age or younger, the plagiocephaly and facial asymmetry usually will correct 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. These, however, are frequently poorly tolerated.

 

Children who present with an SCM pseudotumor may require more prolonged treatment and have less

success with stretching than those children without an SCM tumor.5

 

Surgery is recommended for recalcitrant deformity or when adequate correction is not achieved by 12 to 18 months of age.

 

Children who present after 1 year of age with or without previous treatment are candidates for surgery if they have the following:

 

 

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 12 to 18 months of age.

 

The optimal age for surgery is controversial.

 

The hypothesis is that the sooner the CMT is corrected, the better the chance for correction of the plagiocephaly and facial asymmetry.10

 

If the diagnosis of CMT is in doubt, surgery is contraindicated until a workup has been completed because the torticollis could be caused by conditions other than a tight SCM muscle, 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.

 

The most commonly described procedures are either an unipolar release of the SCM or a bipolar release with or without Z-plasty lengthening of the sternal head.

 

 

Open, percutaneous, and endoscopic techniques have been described for these procedures. We have no experience with percutaneous or endoscopic techniques and strongly prefer an 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, an open unipolar or bipolar release (with or without Z-plasty lengthening) is performed.

 

 

Preoperative Planning

 

Cervical spine radiographs should be reviewed before surgery to look for bony anomalies or cervical scoliosis.

 

 

P.697

 

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 in the midline between the scapulae.

 

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 intraoperatively. This determines the adequacy of the release.

 

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 (FIG 3).

 

 

 

 

FIG 3 • 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, 3- to 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 line with the incision, and the tendon sheaths of the clavicular and sternal heads are exposed.

For the proximal pole exposure, a 2- to 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 the clavicular heads of the SCM muscle. It is commonly used for mild deformities and in younger children.

   

  A 3- to 4-cm long transverse incision is placed parallel and 1 cm proximal to the clavicle between the clavicular and sternal heads of the SCM.

   

  The incision should incorporate a Langer line in the neck. 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.

   

  The two heads of the SCM muscle are then identified.

   

  Surrounding fascia is cleared and both heads are undermined and dissected off of the underlying deep cervical fascia with spreading dissection.

   

  The muscles are elevated with the help of a clamp and divided using electrocautery (TECH FIG 2).

   

   

   

  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.

   

   

  P.698

   

  About 5 to 10 mm of the muscle-tendon segment is excised to prevent further contracture and fibrous adhesions.

   

  Alternatively, the sternal head can be lengthened by Z-plasty.

   

  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. Any remaining tight bands should then be divided. The neck should have a full range of motion after the procedure.

   

  The incision is closed with subcuticular suture after careful hemostasis. The platysma muscle should be closed as a separate layer in order to preserve the appearance of the neck.

• Bipolar Release

 

Bipolar release includes the release of the mastoid insertion of the SCM muscle along with the distal release described earlier.

 

The procedure starts with a distal incision (see discussion earlier).

 

The two heads of the SCM muscle are identified. After undermining the tendons, a small Penrose drain is passed underneath them and clamped.

 

The Penrose drain can be used to gently retract the (intact) SCM muscle and by applying tension to the muscle facilitate proximal exposure and identification of the insertion of the SCM (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.

 

 

 

TECH FIG 3 • A. With tension applied to the tendon at the distal exposure, a safe identification of the origin has been simplified. Furthermore, 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 surgical approach. J Bone Joint Surg Am 1983;65:894-890.)

 

 

A curved clamp is passed just deep to the tendon to elevate it. It can then be safely divided (TECH FIG 3B).

 

There is no need to resect a segment of muscle proximally.

 

After the proximal release is performed, attention is then directed back to the distal incision and a distal release is completed as described earlier.

 

Release of the clavicular head with the lengthening of the sternal head by Z-plasty may be appropriate in older children to help provide a symmetric appearance postoperatively (TECH FIG 3C).8

 

The neck is rotated and bent with the help of the anesthesia team while sequentially palpating both incisions in order to identify any remaining tight bands; any remaining tight bands or fascia is then completely released.

 

Subcutaneous and subcuticular skin closure is then performed after hemostasis. Distally, care should be taken to repair the platysma, as this helps preserve the cosmesis of the neck.

 

 

P.699

 

PEARLS AND PITFALLS

 

	Approach ▪ The distal pole incision is made about 1 cm superior and parallel to the clavicle. Incisions made over the clavicle may result in a hypertrophic scar and unacceptable cosmesis. Incisions close to the midpoint of SCM may compromise the external jugular vein and neurologic structures and may lead to an unacceptable scar. To avoid complications, the proximal horizontal incision is placed just distal to the tip of the mastoid process. Applying tension to the SCM distally simplifies safe identification of its insertion.     Unipolar ▪ Unipolar release is used only in younger patients with mild deformities. release     Bipolar ▪ A bipolar release may be more likely to avoid residual and recurrent deformity. release ▪ The SCM tendon is first exposed at the origin in the distal wound. Both origins of the SCM are elevated to provide tension, the proximal release is then performed, and finally, the distal release is completed.

 

POSTOPERATIVE CARE

 

Postoperative management includes immobilization of the head and neck in a slightly overcorrected position with a rigid cervical collar, custom-made brace, or pinless halo for 2 to 3 weeks (FIG 4).

 

 

The purpose of the brace immobilization is to avoid the preoperative habitual posture which could result in postoperative scarring. It might also help to reprogram the corrected posture as a norm for the child.

 

The brace is removed in 2 to 3 weeks and physical therapy is begun consisting of 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.4, 5, 6

In resistant cases, there is still controversy between unipolar and bipolar release.

Cheng et al3, 4, 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 4 • 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.

Lee et al10 reported improvement in the craniofacial deformity after surgical release of the SCM, with greater correction when the surgery was performed before 5 years of age.

 

 

COMPLICATIONS

Wound breakdown Hematoma Incomplete correction

Neurovascular damage Spinal accessory nerve

Anterior branch of the great auricular nerve

External jugular vein Carotid artery Hypertrophic scar

 

 

 

 

REFERENCES

1. Canale ST, Griffin DW, Hubbard CN. Congenital muscular torticollis: a long-term follow-up. J Bone Joint Surg Am 1982;64:810-816.

    

    

2. Chen CE, Ko JY. Surgical treatment of muscular torticollis for patients above 6 years of age. Arch Orthop Trauma Surg 2000;120:149-151.

    

    

3. Cheng JC, Tang SP, Chen TM. Sternocleidomastoid pseudotumor and congenital muscular torticollis in infants: a prospective study of 510 cases. J Pediatr 1999;134:712-716.

    

    

4. Cheng JC, Tang SP, Chen TM, et al. The clinical presentation and outcomes of treatment of congenital muscular torticollis in infants— a study of 1086 cases. J Pediatr Surg 2000;35:1091-1096.

    

    

5. Cheng JC, Wong MW, Tang SP, et al. 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 2001;83:679-687.

    

    

6. Coventry MB, Harris LE. Congenital muscular torticollis in infancy: some observations regarding treatment. J Bone Joint Surg Am 1959;41:815-822.

    

    

7. Davids JR, Wenger DR, Mubarak SJ. Congenital muscular torticollis: sequela of intrauterine or perinatal compartment syndrome. J Pediatr Orthop 1993;13:141-147.

    

    

8. Ferkel RD, Westin GW, Dawson EG, et al. Muscular torticollis. A modified surgical approach. J Bone Joint Surg Am 1983;65:894-900.

    

    

9. Hummer CD, MacEwen GD. The coexistence of torticollis and congenital dysplasia of the hip. J Bone Joint Surg Am 1972;54:1255-1256.

    

    

10. Lee JK, Moon HJ, Park MS, et al. Change of craniofacial deformity after sternocleidomastoid release in pediatric patients with congenital muscular torticollis. J Bone Joint Surg Am 2012;94:e93.

     

     

    P.700

     

11. 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.

     

     

12. Oh I, Nowacek CJ. Surgical release of congenital torticollis in adults. Clin Orthop Relat Res 1978; (131):141-145.

     

     

13. 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.

     

     

14. 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.

     

     

15. Walsh JJ, Morrissy RT. Torticollis and hip dislocation. J Pediatr Orthop 1998;18:219-221.

     

     

16. 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.