tagmus to search for an associated exophoria in the preferred field of gaze before concluding that the vertical head position results from a vertical null position, because the appropriate surgical management varies according to the underlying condition. Infants with congenital stationary night blindness may present with tonic downgaze and a chin up position to damp an upbeating nystagmus.189a Conversely, infants with congenital downbeat nystagmus may maintain a chin up posture to access their vertical null position (Fig 8.15).19a

Rarely, the two problems coexist, as exemplified by the following case:

A 5-year-old girl had been followed since infancy with congenital nystagmus and a marked chin-down position. Numerous examinations showed that the intensity of the nystagmus dampened in upgaze and increased in downgaze. In addition, she had a V-pattern with orthophoria in upgaze and esotropia in downgaze. The child was treated with bilateral superior rectus recessions and inferior rectus resections with lateral transpositions of the inferior rectus muscles. This procedure transferred the null zone to primary gaze and eliminated the V- pattern.

Vertical head positions are also seen in children with vertical gaze palsy or vertical gaze deviations who must assume an abnormal head position to fixate. Rarely, children with retinal or optic nerve disease associated with altitudinal visual field defects may assume chin-up or chin-down positions,55 reflecting a postural tonus imbalance analogous to the head turn in congenital homonymous hemianopia. Children with overlooking may display tonic upgaze and dystonic chin-up positions, suggesting either that disturbed retinal input can alter postural tonus or that central neurologic dysfunction can contribute to this phenomenon.56 Conversely, premature children with tonic downgaze may maintain a chin-up position to view objects of interest. In children with severe neurological disease, opisthotonus (opistho = behind) may produce hyperextension of the neck, with flexion of the upper limbs and extension of the lower limbs in response to sensory stimuli in children with severe neurological disease.39 This condition may improve with intrathecal baclofen.

Refractive Causes of Torticollis

Ocular refractive errors can lead to anomalous head positions that serve to improve vision (Table 9.1). In point of fact, these cases are exceptionally rare. In 1866, Javal reported that he could no longer see clearly through his astigmatic spectacles when he tilted his head either to the right or left and concluded that ocular torsion (now termed the static ocular counterroll) had occurred.119 Kushner found compensation for refractive errors to be a rare cause of abnormal head posture (found in 1 of 188 patients).134 Patients with bilat-

eral oblique astigmatism may tilt their head to directionalize the astigmatic blur with respect to the vertical meridian.36,134,180,211 Patients with cylindrical lenses may tilt the head to one side to counterroll the eyes into alignment with the axis of the cylinder in the spectacles.74

Undercorrected myopia may cause a patient to elevate the chin or turn the head to gain increased strength from the spectacle lenses. Undercorrected or overcorrected hyperopia may cause patients to adopt a head turn to look through the periphery of the lenses. Patients with anisomyopia and the “heavy eye” syndrome may have a head tilt toward the side of the more myopic eye.149 An 8-year-old girl with homocystinuria and bilateral ectopia lentis was reported to utilize a head tilt to recenter one of the crystalline lenses and obtain phakic vision.133 Although rare, these conditions should be included in the differential diagnosis of enigmatic torticollis. Rubin and Wagner described a patient who maintained a 45-degree head turn that disappeared after correction of an astigmatic refractive error in the right eye.180 They postulated that the patient was using the lid fissures to create a stenopeic slit effect. They also noted that patients with Duane syndrome often have a reduction of head turn after correction of hyperopia. Other reports of patients with anomalous head postures may also be referable to refractive errors. We saw an idiopathic unilateral head turn disappear in a young girl following placement of −1.50 spectacle lenses for both eyes, perhaps because blur was now induced when looking through the corners of the lenses.

Neuromuscular Causes of Torticollis

Congenital Muscular Torticollis

Congenital muscular torticollis is diagnosed in an infant or young child with a unilateral head tilt associated with limited rotation of the head to the opposite side (Fig. 9.6).108 It is differentiated from the more common head tilt associated with superior oblique palsy by the absence of associated vertical strabismus and by the palpable restriction to passive rotatory motion to the opposite side.

Congenital muscular torticollis has been subdivided into three groups.113,144,201 Soon after birth, a mass appears in the belly of the sternocleidomastoid muscle (SCM) (fibromatosis colli), and the patient develops a head tilt to the side of the involved muscle.53,122 After several months, the mass or tumor disappears as signs of facial asymmetry become more evident (Fig. 9.5). In most cases, the head tilt subsequently resolves, and the facial asymmetry normalizes over the first year of life, with or without physical therapy.53 When the head tilt persists, the affected SCM is found to be hard and tight to palpation.113

Fig. 9.6  Five-month old girl with congenital muscular torticollis. Note facial asymmetry (deformational plagiocephaly)

This is the most common presentation. Group 2, known as MT (muscular torticollis), consists of torticollis with tightness of the SCM but no palpable tumor. 40,68,106 The last group, Group 3 (also known as POST), is a postural torticollis without a mass or tightness of the SCM.41

Facial asymmetry (termed “facial scoliosis” in the older literature) is generally regarded as a ubiquitous finding in children whose congenital muscular torticollis fails to resolve spontaneously. It is considered to be an inevitable consequence of a permanent oblique head posture of long duration.110 As the neck and facial bones assume larger proportions, the fibrotic SCM fails to elongate normally, producing pathological changes of the face and skull. The eyebrow on the side of the shortened muscle tends to slope downward, and the portion of the face below the level of the eye becomes shorter and wider on the affected side than the corresponding normal side (Fig. 9.5). The frontal eminence is flattened on the affected side, and there is a well-marked bulge in the occipital region, while on the other side, the eminence is unduly prominent and the occipital region is rather flat. The vault of the skull is “thrown back” on the affected side and “pushed forward” on the opposite side, resulting in “deformational plagiocephaly.” Facial asymmetry progressively increases as growth continues and the cervical curve continues. It often resolves following early surgical intervention and, in some older children, shows a gradual reversal following surgical repair.32,113,142

The etiology of congenital muscular torticollis is controversial. Ho et al106 found that there was a 53% rate of firstborn children affected and a higher incidence of traumatic delivery in those with congenital muscular torticollis. These data support the concept of intrauterine crowding (from a

small uterus in the firstborn) and malposition, which could lead to more difficult, traumatic deliveries. Venous compression on the neck may also contribute. For reasons that are unclear, the incidence of torticollis associated with positional (deformational) plagiocephaly appears to be increasing.57 Congenital muscular torticollis is frequently associated with a history of some obstetrical difficulty.110

Histologically, it is characterized by contracture of the SCM, without osseous deformity, local inflammation, or primary neural abnormality.33 Excisional biopsies of the tumor have shown a hard, white, fibrous lesion that resembles a fibroma with no evidence of hematoma or injury.141 The sternal head of the muscle is almost completely replaced by fibrous tissue. Sarnet and Morrissy185 suggested that the separate arterial supply of the sternal head predisposes to ischemia, focal myopathy, and fibrosis, while the grouped atrophy in the clavicular head was consistent with the combination of secondary entrapment neuropathy of the spinal accessory nerve resulting from its passage through a myopathic sternal head on its way to the clavicular head.

An association of congenital muscular torticollis with congenital hip dysplasia seems wellestablished. Hummer and MacEwen114 retrospectively reviewed records from 70 children with congenital muscular torticollis and found congenital dislocation of the hip in 5% and congenital subluxation of the hip in 15%. There was no statistically significant relationship between the side of the torticollis and the side of the hip dysplasia. Interestingly, Busch and Westin33 found congenital hip dislocation or dysplasia in 9 of 36 patients, which always involved the hip ipsilateral to the tight cervical muscles. Clinical and neuroradiographic examination of the hip joints is now considered a part of the routine evaluation of congenital muscular torticollis.

Conservative treatment of congenital muscular torticollis consists of passive tilting of the head in the direction opposite the deformity, rearrangement of the crib to encourage the infant to lie on the affected side, and special neck braces in some cases.33 Approximately 80% of infants respond to conservative measures and do not require surgical release.33,37 Canale et al37 found that an exercise program is more likely to be successful when the restriction of motion is less than 30 degrees and there is little or no facial asymmetry. Approximately 50–70% of sternocleidomastoid tumors resolve spontaneously during the first year of life with minimal residual deficits. Physical therapy with manual stretching exercises is helpful for cases associated with restriction. Results of treatment with botulinum injection have been mixed at best.49 For resistant cases, surgical lengthening of the affected muscle is indicated.

Beyond 1 year of age, congenital muscular torticollis does not generally respond to conservative measures. Previous surgical treatment of congenital muscular torticollis consisted of surgical transection of the contractured SCM, which often produced unsightly clavicular prominence