Imaging in Acute Torticollis

1. Imaging in Acute Torticollis

3. At the Conclusion of this Exhibit One Should Be Able To: Define torticollis Describe an algorithm for imaging patients presenting with torticollis List several potential causes of torticollis and describe their typical imaging features Discuss the concept of atlanto-axial rotatory fixation and its diagnosis

4. Introduction: What is Torticollis? Derived from the Latin tortus (twisted) + collis (neck or collar) Torticollis is defined as abnormal twisting of the neck which causes the head to be held in a rotated or tilted position.

5. Introduction: Clinical Aspects of Acute Torticollis Torticollis refers to a symptom rather than a distinct disease process It can be caused by a wide variety of conditions (over 80 causes have been described) which range from relatively innocuous to life-threatening May be congenital or acquired Occurs more frequently in children than in adults The right side is affected in 75% of patients

6. Introduction: Chronic Sequelae of Torticollis Physical Positional plagiocephaly Facial deformities Cervical spine degeneration Radiculopathies and myelopathies Psychiatric Major depression Agoraphobia Substance abuse OCD

7. Imaging of Patients with Torticollis Choice of imaging studies depends on age and if history of trauma is present. In newborn infants with congenital muscular torticollis, ultrasound is preferred and often diagnostic. In older children and adults with post trauma torticollis, CT of neck/cervical spine is needed to exclude fracture or malalignment. If CT is positive, MRI and MRA of the neck should be considered to evaluate for associated cord, ligamentous, or arterial injuries. In older children and adults presenting with torticollis without trauma, neck/cervical spine CT is the initial imaging study; if negative, then brain and cervical spine MRI is performed to exclude a CNS cause of torticollis.

8. Imaging Algorithm for Acute Torticollis

9. Causes of Torticollis

10. Traumatic Causes of Torticollis Muscular Fibromatosis colli Muscle spasm following trauma Skeletal Unilateral interfacetal dislocation (UID) Occipital condyle fractures Atlanto-axial rotatory fixation (? truly traumatic) CNS related Subarachnoid hemorrhage Spinal epidural hematoma

11. Traumatic Causes of Torticollis: Fibromatosis Colli Rare form of infantile fibromatosis affecting sternocleidomastoid muscle (SCM) Accounts for >80% of childhood cases of torticollis Due to traumatic delivery or possibly abnormal head position in utero Infants usually appear normal at birth, torticollis develops in the 2-3rd weeks of life More common in males and in right side Sonographic findings are typical

12. Traumatic Causes of Torticollis: Fibromatosis Colli Longitudinal US views of the right (top) and left (bottom) SCMs in an infant with torticollis. The right SCM is enlarged and of heterogeneous echotexture. The left SCM is normal. There are mildly enlarged lymph nodes posterior to the left SCM

13. Traumatic Causes of Torticollis: Fibromatosis Colli Axial contrast CT in an infant with fibromatosis colli. The right SCM is enlarged and has faint central enhancement (arrowhead).

14. Traumatic Causes of Torticollis: Unilateral Interfacetal Dislocation Axial CT image and a saggital reformatted imagedemonstrate right facet dislocation (arrows).

15. Traumatic Causes of Torticollis: Occipital Condyle Fracture Axial and coronal reformatted CT images show a right occipital condyle fracture (type III) in a patient presenting with acute torticollis after trauma.

16. Occipital Condyle Fractures Classified into 3 types by Anderson and Montesano I Axial loading fracture limited to the occipital condyle without displacement into foramen magnum II Fracture of basiocciput extending into occipital condyle III Small fragment arising from medial surface of condyle avulsed by an intact alar ligament and distracted towards dens

17. Infectious and Inflammatory Causes of Torticollis CNS related Meningitis Head and Neck related Upper respiratory infections Otitis media Mastoiditis/Bezold’s abscess Cervical adenitis Retropharyngeal abscess Spine related Vertebral osteomyelitis and/or discitis Epidural abscess Rheumatoid arthritis

18. Infectious Causes of Torticollis: Mastoiditis/Bezold’s Abscess Unenhanced (right) and enhanced (left) axial CT images in a patient with acute torticollis and right ear pain demonstrate coalescing mastoiditis eroding medial surface of mastoid (arrow). Inferior to this is an abscess involving the right SCM (arrowhead).

19. Bezold’s Abscess Rare complication of suppurative mastoiditis occuring when infection erodes the mastoid tip into the neck, forming an abscess May cause spasm of the SCM, resulting in torticollis Abscess may spread down the plane of the sternocleidomastoid muscle into the lower neck Also associated with cholesteatomas

20. Infectious Causes of Torticollis: Suppurative Adenitis Enhanced axial fat suppressed T1 MR image demonstrates a necrotic retropharyngeal lymph node (arrowhead) in a child with suppurative adenitis presenting as acute torticollis.

21. Infectious Causes of Torticollis: Discitis and Osteomyelitis T1 post-Gd

22. Inflammatory Causes of Torticollis: Rheumatoid Arthritis Unenhanced sagittal T1 MR in a patient with rheumatoid arthritis and torticollis. There is pannus destroying the dens and compressing the lower brainstem and medulla.

23. Neoplastic Causes of Torticollis CNS tumors Spinal cord or brainstem tumors Posterior fossa tumors and cysts Vestibular schwannoma Metastases Bone tumors Vertebral eosinophilic granuloma Osteoid osteoma/osteoblastoma Metastases (spine or skull base)

24. Neoplastic Causes of Torticollis: Spinal Cord Tumor Sagittal enhanced T1 MRI of the cervical spine demonstrates an enhancing, expansile ganglioglioma in a 10- year-old female presenting with acute torticollis.

25. Neoplastic Causes of Torticollis: Skull Base Tumor Axial enhanced T1 MRI in an adult with acute torticollis demonstrates a metastasis from renal cell carcinoma (arrowheads) involving the left occipital condyle.

26. Other Causes of Torticollis Dystonic syndromes (idiopathic spasmodic torticollis) Chiari 1 malformation Syringomyelia Neuroleptic drug reactions Congenital vertebral anomalies (e.g. – congenital scoliosis, cervical segmentation anomalies, Klippel-Feil syndrome) Hemifacial microsomia Oculomotor nerve palsies/Strabismus Gastroesophageal reflux (Sandifer’s syndrome) Vascular abnormalities (craniocervical AV fistula; congenital hypoplasia of the internal carotid artery) Pseudotumor cerebri

27. Other Causes of Torticollis: Chiari I Malformation Unenhanced midsagittal T1 weighted MR image shows significant downward displacement of peg-shaped cerebellar tonsils (arrowhead) through foramen magnum (type I Chiari malformation).

28. Other Causes of Torticollis: Chiari I Malformation with a Syrinx Unenhanced sagittal T1 weighted image demonstrates a large, expansile, multiseptated cyst in the cervical cord of a patient with a Chiari I malformation and torticollis.

29. Chiari I Malformation Defined as greater than 5 mm of displacement of triangular-shaped cerebellar tonsils below the foramen magnum Believed to be due to an abnormality of expression of spinal segmentation genes that lead to varying degrees of hypoplasia of the skull base Unclear if torticollis is due to associated skeletal abnormalities or due to compression of brainstem and lower cranial nerves Torticollis may be caused by syringohydromyelia even in absence of a Chiari malformation

30. Other Causes of Torticollis: Klippel-Feil Syndrome Lateral radiograph of the cervical spine shows hypoplasia and fusion of lower cervical vertebrae in a patient with Klippel-Feil syndrome and torticollis

31. Klippel-Feil Syndrome Heterogeneous group of conditions unified by presence of congenital synostosis of some or all cervical vertebrae Classic triad described by Klippel and Feil consisting of short neck, low posterior hairline, and limited range of motion of neck (seen in <50% of patients) Commonly associated abnormalities include congenital scoliosis, rib abnormalities, deafness, genitourinary abnormalities, Sprengel’s deformity, and cardiac abnormalities Along with congenital scoliosis, accounts for nearly 1/3 of nonmuscular causes of torticollis in children Cervical anomalies are well characterized by CT

32. Idiopathic Spasmodic Torticollis(IST) Also referred to as cervical dystonia Nontraumatic, acquired form of torticollis presenting as spasms or jerks of SCMs Females more commonly affected by 4.5:1 Typically occurs in adults over age 30 Diagnosis requires exclusion of other potential causes of torticollis and that symptoms be present for at least 6 months Conventional neuroimaging studies usually negative

33. Idiopathic Spasmodic Torticollis(IST) Although pathophysiology of IST is not understood, the interstitial nucleus in the brainstem has been implicated as a probable site of abnormality IST may be due to abnormalities of the basal ganglia, vestibular systems, or spinal accessory nerves Proton MR spectroscopy in IST patients may demonstrate diminished n-acetyl-aspartate (NAA) levels in basal ganglia when compared with normal controls

34. Proton MR Spectroscopy inIdiopathic Spasmodic Torticollis Long echo time proton MRS at level of left basal ganglia (left) demonstrates low level of n-acetyl-aspartate relative to normal right basal ganglia (right).

35. Atlanto-axial Rotatory Fixation Atlanto-axial rotatory fixation (AARF) is a controversial entity - Is it the result of or the cause of torticollis? True atlanto-axial subluxation or dislocation is rare 75-80% of reported cases occur in children Compression of spinal cord may occur if there is anterior or posterior displacement Vertebral artery kinking or stretching may occur and cause posterior circulation ischemic symptoms

36. Atlanto-axial Rotatory Fixation Frequently, there is an antecedent history of trauma or upper respiratory infection “Grisel’s syndrome” = non-traumatic atlanto-axial subluxation secondary to ligamentous laxity and inflammation following infection or surgery in the head and neck region It has been postulated that swollen capsular and synovial tissues and muscle spasm prevent reduction early on and that ligament and capsular contractures develop later, ultimately causing fixation

37. Types of Atlanto-axial Rotatory Fixation (Fielding classification) Type 1 Rotatory fixation w/o anterior displacement of atlas (intact transverse and alar ligaments) – most common type Type 2 Rotatory fixation with 3-5 mm of anterior displacement of atlas (implies deficiency of transverse ligament) Type 3 Rotatory fixation with >5 mm of anterior displacement of atlas (implies deficiency of both transverse and alar ligaments) Type 4 Rotatory fixation with posterior displacement of atlas (implies deficiency of odontoid process)

38. Types of Atlanto-axial Rotatory Fixation (Fielding classification) From Lustrin ES, Karakas SP, Ortiz AO, et al. Pediatric cervical spine: Normal anatomy, variants, and trauma. Radiographics 2003; 23:539-60. (Used with permission)

39. Radiographic Diagnosis of Atlanto-axial Rotatory Fixation CT is essential for imaging of AARF When rotation is accompanied by anterior or posterior displacement (Fielding types 2-4), CT is diagnostic Type 1 rotatory fixation appears identical to other causes of torticollis when patients are imaged at rest Thus, patients with suspected type 1 AARF should be scanned at rest and with maximal voluntary contralateral head rotatation CT in patients with AARF shows little or no change in position of atlas with respect to axis

40. Type 1 Atlanto-axial Rotatory Fixation Axial CT image with head rotated to left shows widened space between dens and right C1 lateral mass which persists with rotation of head to right (arrowheads) compatible with AARF. The atlanto-dental interval is normal making this a type 1 AARF.

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