Introduction C1-C2 rotatory instability (fixed rotation of C1 on C2) caused by subluxation or facet dislocation common cause of childhood torticollis spectrum of disease that ranges from mild subluxation to fixed facet dislocation Pathophysiology common causes include infection (~35%) may have history of pharyngitis or otitis media Grisel's disease is the condition of AARD following a respiratory infection or retropharyngeal abscess thought to be linked to lymphatic edema in area of cervical spine trauma (~24%) recent head or neck surgery (~20%) idiopathic associated conditions Down's syndrome rheumatoid arthritis tumors congenital anomalies pathoanatomy mechanism is thought to be related to ligamentous laxity transverse ligament integrity transverse ligament is intact spinal canal stenosis can only occur with severe rotation and facet dislocation transverse ligament is ruptured and there is a component of anterolithesis (> 5mm), then spinal canal stenosis can occur with less rotation (45 degrees) vertebral arteries may also be at risk Anatomy Axis Osteology axis has odontoid process (dens) and body embryology develops from five ossification centers subdental (basilar) synchondrosis is an initial cartilagenous junction between the dens and vertebral body that does not fuse until ~6 years of age the secondary ossification center appears at ~ age 3 and fuses to the dens at ~ age 12 Occipital-C1-C2 ligamentous stability provided by the odontoid process and its supporting ligaments transverse ligament limits anterior translation of the atlas apical ligaments limit rotation of the upper cervical spine alar ligaments limit rotation of the upper cervical spine Classification Fielding Classification of AARD Type I • Unilateral facet subluxation with intact transverse ligament • Odontoid acts as a pivot point with 1 facet subluxating anteriorly, 1 facet subluxating posterioly. • Most common and benign type Type II • Unilateral facet subluxation with 3 to 5 mm of anterior displacement. • Injured Transverse ligament • 1 facet acts as pivot point and 1 lateral mass is displaced anteriorly Type III • Bilateral anterior facet displacement of > 5 mm. • Rare with higher risk of neurologic involvement or instantaneous death. • Both lateral masses are displaced Type IV • Posterior displacement of atlas (C1) (with odontoid fracture, or hypoplastic dens) • Rare with higher risk of neurologic involvement or instantaneous death Physical Exam Symptoms tilted head neck pain headache Physical exam ipsilateral rotation and contralateral tilt of the head in relation to the lateral mass of C1 chin rotated to the side opposite the facet subluxation (e.g. right sided facet subluxation will have chin rotated to the left) contra-lateral sternocleidomastoid may be spastic sternocleidomastoid (SCM) spasm occurs on the SAME side as the chin (e.g. right sided facet subluxation will have chin rotated to the left, and left SCM will be spastic) this protective spasticity occurs to reduce further subluxation C1-C2 subluxation (and resultant chin position) is primary, SCM spasm is secondary/reactive in contrast to congenital muscular torticollis where the SCM spasm occurs on the OPPOSITE side of the chin (e.g. left SCM spasm will rotate the head to the right, and chin will be on the right) SCM spasm is primary reduced cervical rotation Imaging Radiographs recommended views AP, open-mouth odontoid look for variation in size and distance from midline of C2 lateral masses (reflects rotation) lateral facet joint appears anterior and wedge shaped instead of normal oval shape cervical flexion & extension views may be useful to exclude instability may be difficult due to position of head and resisted neck motion Dynamic CT is diagnostic gold standard take CT with head straight forward, and then in maximal rotation to right and left will see fixed rotation of C1 on C2 which does not change with dynamic rotation MRI of little value unless neurologic symptoms Treatment Nonoperative soft collar, NSAIDS, exercise program indications subluxation present for < 1 week (traumatic or Grisel's disease) many patients probably reduce spontaneously before seeking medical attention head halter traction, NSAIDS, benzodiazepines, then hard collar x 3 months indications subluxation persists > 1 week persistent torticollis in spite of soft collar (above) x 2 weeks technique small amount (5 lbs.) usually enough either in hospital or at home muscle relaxants and analgesics may be needed halo traction, then halo vest x 3 months indications subluxation persists > 1 mos. failed halter traction x 2 weeks (above) Operative posterior C1-C2 fusion indications subluxation persists > 3 mos neurologic deficits present failed halo traction x 2 weeks recurrent subluxation Complications Missed diagnosis diagnosis is often missed delayed
QUESTIONS 1 of 3 1 2 3 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ10.167) A 5-year-old boy develops spontaneous atlantoaxial rotatory subluxation shortly after an upper respiratory infection. No neurologic symptoms are present. He is initially treated with soft collar immobilization and rest. After a week, he continues to hold his head tilted and rotated with no change in his neurologic status. A current cervical radiograph is shown in Figure A. What is the next most appropriate treatment option for this patient? Tested Concept QID: 3260 FIGURES: A Type & Select Correct Answer 1 C1-C2 arthrodesis 5% (206/4454) 2 Continued soft collar immobilization and rest 14% (608/4454) 3 Halter traction, muscle relaxants and analgesics 58% (2598/4454) 4 Halo skeletal traction 8% (362/4454) 5 Cervical stretching and immobilization in a stiff collar 15% (654/4454) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review tested concept (OBQ06.66) A 3-year-old girl developed torticollis eight months ago after a severe respiratory tract infection. A initial trial of halter traction was attempted without success. A trial of halo traction was then performed for 3 weeks and then a dynamic computed tomographic (CT) was obtained and shown in Figure A. Panel (a) shows an axial image with maximal rotation to the left. Panel (b) shows an axial image with maximal rotation to the right. What is the most appropriate next step in management? Tested Concept QID: 177 FIGURES: A Type & Select Correct Answer 1 No further treatment 46% (1973/4257) 2 Closed reduction under conscious sedation 4% (185/4257) 3 Closed reduction under general anesthesia in the operating room with neurologic monitoring 17% (721/4257) 4 Occipitocervical fusion 4% (171/4257) 5 Posterior atlantoaxial fusion 27% (1159/4257) L 4 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review tested concept
All Videos (0) Podcasts (1) Spine⎪Atlantoaxial Rotatory Displacement (AARD) Orthobullets Team Spine - Atlantoaxial Rotatory Displacement (AARD) Listen Now 14:49 min 1/31/2020 103 plays (6)
Acquired torticollis / Atlantoaxial instability with Os Odontoideum (10yo male) (C1591) Ayush Sharma Spine - Atlantoaxial Rotatory Displacement (AARD) E 8/14/2013 1067 0 10 Orthopaedics Overseas / Health Volunteers Overseas Nicaragua, Obliquity of Posterior Ring of C1 (C1158) Spine - Atlantoaxial Rotatory Displacement (AARD) E 2/20/2012 60 0 2