Operative Techniques in Orthopaedic Surgery (4 Volume Set) 1st Edition

162. Release of the Sternocleidomastoid Muscle

Gokce Mik and Denis S. Drummond

DEFINITION

images The sternocleidomastoid (SCM) muscle is a major muscle of the neck that laterally flexes and rotates the head.

images 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.

images Congenital muscular torticollis (CMT) associated with a contracture of the SCM muscle is the most common etiology of torticollis in infants.

images 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

images Shortening and contracture of the SCM muscle results in tightness that gives the typical clinical appearance, which is detected at birth or shortly thereafter.

images Cheng et al3 subdivided the CMT patients into three groups:

images Clinically palpable sternomastoid “tumor” or pseudotumor

images Muscular torticollis group without palpable or visible tumor but with clinical thickening or tightness of the SCM on the affected side

images All the clinical features of torticollis with neither a palpable mass nor tightness of the SCM muscle

ANATOMY

images On each side, the SCM muscle passes obliquely across the side of the neck and divides the neck into anterior and posterior triangles.

images It originates from two heads.

images Sternal head: superior and anterior surface of manubrium sterni.

images 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.

images The functions of sternocleidomastoid are multiple.

images With unilateral contraction, it:

images Flexes the head and cervical spine ipsilaterally

images Laterally rotates the head to the contralateral side

images With bilateral contraction, it.

images Protracts the head

images Extends the incompletely extended cervical spine

images The SCM is innervated by the.

images Spinal accessory nerve (XI)

images Ventral ramus of second cervical nerve (C2)

images 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.

images 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.

images 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.

images The SCM protects the carotid artery and internal jugular vein, both of which lie deep to it.

images 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.

images The anatomy of the SCM muscle and important surrounding structures is shown in FIGURE 1.

PATHOGENESIS

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

images Infants with CMT most often have a history of difficult or traumatic delivery.

images 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.

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

images

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.

images CMT may occur in association with oligohydramnios, multiple births, first-born children, and developmental dysplasia of the hip (DDH).

images 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.

images However, CMT found in the infants who are delivered by cesarean section is not consistent with the theory of birth trauma.

images The data that show 20% coexistence of developmental dysplasia of the hip support the theory of intrauterine malposition and crowding.9

images 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.

images 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

images Tang et al13 explained the success of conservative management (stretching exercises) with the presence of myoblast cells besides fibroblast cells.

images In vitro, myoblasts could be mechanically stimulated to undergo both hypertrophy and hyperplasia by intermittent stretching and relaxation.

images The pathogenesis of the torticollis resulting from pathologies other than CMT is affiliated with other conditions or syndromes.

NATURAL HISTORY

images Diagnosis of CMT is usually made at or near birth. Other causes of torticollis generally present later (4 months to 1 year).

images A mass (SCM tumor) or fullness in the SCM muscle usually exists within a few weeks or months after delivery.

images Typically, the mass decreases in size and disappears between 6 and 12 months of age.

images If it remains untreated, contraction and sometimes a fibrous bundle can occur in the muscle.

images Flexion and rotation deformity of the neck begins in infancy.

images Typically the head turns toward the involved side and the chin points to the opposite shoulder.

images Plagiocephaly and facial asymmetry may be present early on; they increase with time.

images In persistent cases, deformity progresses and becomes inflexible.

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

images 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.

images Formation of a lateral band is mostly responsible for limited neck mobility.

images 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

images A complete history and physical examination should be done in newborns with torticollis.

images The incidence of the breech presentation and birth trauma in children with CMT is higher than the general population.

images There is known coexistence of DDH with torticollis.

images The reported incidence of DDH with CMT varies from 8% to 20%.9,15

images A clinical examination of the hip and ultrasonography screening are thus required for children with CMT.

images A previous belief that CMT was associated with metatarsus adductus and clubfoot is not supported by the literature.

images Typically, children with CMT hold their head laterally flexed to the affected side and rotate their face to the opposite side.

images 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.

images Any degree of restriction should be noted during the examination.

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

images 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).

images

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.

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

IMAGING AND OTHER DIAGNOSTIC STUDIES

images Radiographs

images 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.

images 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

images 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.

images 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.

images Hip ultrasonography should be routinely done in patients born with CMT.

images There is a relatively high incidence of coexistence between CMT and DDH.

images 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.

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

DIFFERENTIAL DIAGNOSIS

images 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.

images Neurologic causes such as the postural head tilt seen with posterior fossa tumors must be ruled out.

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

images About 10% of posterior fossa tumors initially present with torticollis.

images The other orthopaedic causes of torticollis include congenital cervical vertebral anomalies (scoliosis, Klippel-Feil syndrome) and atlantoaxial rotational instability.

images Grissel syndrome: torticollis associated with retropharyngeal abscess or post-tonsillectomy status.

images Neck abscess or inflammatory disorders

images Sandifer syndrome (reflux)

images Neurologic

images Posterior fossa tumors

images Dystonia

NONOPERATIVE MANAGEMENT

images The initial treatment of CMT is nonoperative and is successful in the vast majority of infants by 1 year of age.

images A program of gentle stretching exercises should include flexion–extension, lateral bending away from the involved side and rotation toward it.

images Stretching exercises can be done by a physical therapist or by the parents with a home program.

images In our experience, a supervised home program monitored by a physical therapist is the most successful method.

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

images 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.

images 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.

images The duration of the conservative treatment could be longer in children who have SCM tumor at initial presentation.

images The success rate of manual stretching in these patients is lower than those without a SCM tumor.4

images Surgery is recommended for recalcitrant deformity when adequate correction is not achieved by 1 year of age.

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

images Significant head tilt with tight band or contracture of the SCM muscle

images Limitation of passive head rotation and lateral flexion by more than 10 to 15 degrees

SURGICAL MANAGEMENT

images 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.

images 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.

images 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.

images The operative techniques described for CMT are based on release or lengthening of the tight and shortened SCM muscle.

images 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.

images 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

images For infants, a home stretching program is taught and supervised by a physical therapist for 6 months.

images In children with appropriate surgical indications, bipolar release (with or without Z-plasty lengthening) is carried out.

images 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.

images 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

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

images In fixed deformities, positioning of the head can be difficult for the anesthesiologist. Flexible fiberoptic intubation should then be considered.

images The ear is taped anteriorly and hair around the mastoid process is shaved.

Positioning

images The procedure is performed under general anesthesia in the supine position. A sandbag is placed to elevate the shoulder on the affected side.

images The endotracheal tube should be kept at the unaffected side so as not to interfere with the operative field.

images Draping should allow the correction to be evaluated by bending the neck. This determines the adequacy of the release intraoperatively.

images The shoulder draping should permit the anesthesiologist to hold the shoulder, which can maximize tension during this test.

images 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

images  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).

images  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.

images  For the proximal pole exposure, a 2to 3-cm horizontal incision is made just distal to the tip of the mastoid process.

images  The dissection is carried deeper until the periosteum of the mastoid process is exposed. The insertion of the muscle is then exposed subperiosteally.

images

TECH FIG 1 • Proximal and distal incisions (dotted lines).

DISTAL UNIPOLAR RELEASE

images  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.

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

images  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.

images  Two heads of the SCM muscle are identified as described.

images  Surrounding fascia is cleared and the sternal head or both heads are undermined with a curved clamp.

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

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

images

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.

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

images  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.

images  The incision is closed with subcuticular suture after careful hemostasis.

BIPOLAR RELEASE (AUTHORS' PREFERENCE)

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

images  The procedure starts with a distal incision.

images  The two heads of the SCM muscle are identified. After undermining the tendons, the curved clamp is left underneath them.

images 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.

images  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).

images  Attention is directed to the proximal insertion and the incision is placed as described before.

images  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.

images  A curved clamp is passed just deep to the tendon to elevate it so it can be sectioned completely (TECH FIG 3B).

images There is no need to resect a segment of muscle at the proximal part.

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

images 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

images  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.

images  Both surgical areas are checked to identify if any remaining tight bands or fascial structures are impeding full correction. They are divided carefully.

images  Subcutaneous and subcuticular skin closure is then performed after hemostasis.

images

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.)

images

POSTOPERATIVE CARE

images 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).

images 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.

images The brace is removed in 3 weeks and passive stretching is recommended as well as active strengthening exercises.

images Exercises are continued at home for 3 to 6 months.

OUTCOMES

images Early conservative management is successful in over 90% of children with CMT who are younger than 1 year.3,4,6

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

images Cheng et al35 reported excellent results in children operated on at age 6 months to 2 years with unipolar release.

images Canale et al1 found better results after bipolar release, although the difference was not statistically significant.

images Wirth et al16 reported satisfactory results in 48 of 55 patients who had undergone bipolar release, with low recurrence rates (1.8%).

images

FIG 3  Pinless halo device for postoperative management.

images 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.

images 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

images Wound breakdown

images Hematoma

images Residual lateral band

images Neurovascular damag.

images Spinal accessory nerve

images Anterior branch of the great auricular nerve

images External jugular vein

images Carotid artery

images 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.



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