bubble_chart Overview

Congenital muscular torticollis is a congenital deformity characterized by the head and neck tilting toward the affected side due to contracture of the sternocleidomastoid muscle on one side.

bubble_chart Etiology

The cause of congenital muscular torticollis remains unclear. However, there are several theories:

1. Trauma theory: A neck mass can be palpated at birth or within two weeks after birth, which is related to factors such as breech delivery or the use of forceps. However, some newborns delivered by cesarean section can also develop torticollis.

2. Intrauterine pressure theory: Abnormal positioning of the fetal head and neck in the uterus leads to ischemia of the sternocleidomastoid muscle.

bubble_chart Pathological Changes

The lesion may involve the entire sternocleidomastoid muscle or be limited to its sternal or clavicular attachments. The pathological change is muscle fibrosis. Transmission electron microscopy confirms muscle degeneration, with a significant increase in interstitial collagen deposition, which results from the replacement of muscle by nonspecific fibrous tissue.

bubble_chart Clinical Manifestations

The head and neck tilt toward the affected side, with a small number of infants showing this condition at birth, while most develop it within two weeks after birth. The head tilts toward the affected side, and the chin turns toward the unaffected side. A movable, oval or spindle-shaped mass can be palpated at the middle to lower third of the sternocleidomastoid muscle, with no fixation at its base. There is no redness, swelling, heat, or pain, and the mass is firm in texture. It may grow to about 2 cm within a 4-day cycle of day and night. In most cases, the mass disappears on its own within six months. By this time, the contracture of the sternocleidomastoid muscle gradually worsens. Secondary deformities of the head and face become more pronounced, with the affected side of the face appearing smaller, the eyes no longer level, and limited rotation of the jaw toward the affected side. The contracted sternocleidomastoid muscle becomes cord-like. X-ray images show no abnormalities in the cervical vertebrae.

bubble_chart Diagnosis

The diagnosis can be made based on the presence of a hard neck mass that appears within two weeks after birth, without redness, swelling, heat, or pain, with clear boundaries and mobility, and no abnormalities seen on cervical X-rays.

bubble_chart Treatment Measures

1. Non-surgical therapy When a neck mass is detected in the neonatal period, parents should perform passive stretching exercises on the child's neck under the guidance of a physician. The head should first be stretched toward the unaffected side, then to be decocted later the jaw is turned toward the affected side. Each movement should be performed slowly, with passive neck exercises done 3–4 times daily, each lasting about 10 minutes. Additionally, during breastfeeding, the affected side should be fixed against the mother's chest to stretch the affected side. When playing with the infant, standing on the affected side also serves as a method to stretch the sternocleidomastoid muscle. Local physiotherapy may also be supplemented. After about one year of conservative treatment, approximately 76–86% of children can achieve correction.

2. Surgical treatment For children over one year old who do not respond to conservative treatment or have not received treatment, due to muscle fibrosis and facial deformity, surgical intervention is necessary to correct the deformity. The optimal age for surgery is 1–5 years. Surgery performed before one year of age may lead to scar adhesions and increase the risk of pulmonary complications after general anesthesia intubation. For children over five years old, secondary deformities are more severe, making facial correction more difficult. Commonly used surgical methods include:

(1) Release and division of the sternal and clavicular heads of the sternocleidomastoid muscle A transverse incision parallel to the clavicle, approximately 4 cm in length, is made above the medial clavicle to expose the sternal and clavicular heads of the sternocleidomastoid muscle. A hemostat is passed behind the muscle origin, lifted, and then the muscle is divided. A 2 cm segment of the muscle stump is excised to prevent postoperative adhesion. The residual contracted muscle and fascial membrane bands are checked manually and carefully released. The anesthesiologist is instructed to rotate the child's head. If neck movement remains partially restricted despite complete soft tissue release, further release and division of the mastoid head of the muscle should be performed. The subcutaneous tissue and skin are sutured, but the platysma muscle should not be sutured, as this may interfere with postoperative head fixation in an overcorrected position. A rubber drain is placed in the wound and removed after 24 hours.

(2) Z-lengthening of the sternocleidomastoid muscle To improve postoperative neck aesthetics, some scholars in recent years have adopted the Z-lengthening technique for the sternocleidomastoid muscle. The clavicular and sternal ends of the muscle are exposed, the clavicular end is transected above the clavicle, and the sternal end is lengthened in a Z-shaped fashion. Our hospital has performed 10 cases of sternocleidomastoid muscle Z-lengthening over the past two years, with satisfactory functional and aesthetic outcomes.

Postoperative management: A neck collar is worn for three months. For children over six years old, the head should be fixed in an overcorrected position. For children under two years old, passive head and neck exercises should be performed daily to maintain range of motion (Figure 1). Some scholars recommend wearing a brace at night for four weeks postoperatively, with functional head and neck exercises during the day.

Figure 1 (A) Right congenital muscular torticollis (B)(C) Schematic diagram of manual passive exercises (D) Anatomy of the right sternocleidomastoid muscle

bubble_chart Differentiation

1. Congenital cervical deformity The neck is short and thick with reduced mobility, commonly seen in cervical hemivertebrae, cervical fusion (Klippel Feil Syndrome), etc.

2. Cervical subluxation Mostly occurs in children aged 3–5 years. After pharyngeal inflammation, congestion of the soft tissues around the cervical spine leads to sudden head and neck deviation, limited movement, and tense neck muscles. An open-mouth anteroposterior and lateral cervical X-ray may reveal a _C1–2 subluxation.

3. Ophthalmic diseases If a child has {|###|}myopia on one side and farsightedness on the other, head and neck tilting to one side may occur. However, there is no contracture of the sternocleidomastoid muscle, and head and neck rotation is not restricted.

4. Others Cervical disc lesions, spinal cavity disorders, absence of one sternocleidomastoid muscle, etc., can also cause head and neck tilting.