etiology The atlantoaxial joint is an important "transitional zone" in the cervical spine prone to instability by both degenerative and traumatic processes. Pathophysiology adult causes degenerative Down's syndrome Rheumatoid Arthritis Os odontoideum traumatic Type I odontoid fracture (very rare) Atlas fractures Transverse ligament injuries pediatric causes degenerative JRA Morquio's Syndrome lysosomal storage disorder trauma/infection rotatory atlantoaxial subluxation Anatomy Osteology bony articulations C1-C2 facet joints Ligaments transverse apical alar ligament complex transverse ligament most important stabilizer apical ligament single midline structure alar ligaments paired parasagittal ligament Biomechanics the atlantoaxial joint provides ~50% of rotation in the cervical spine this is enabled by the peg (C2)-ring(C1) anatomy Physical Exam Symptoms symptomatic neck pain neurologic symptoms Physical exam neurologic deficits often appear late in disease process due to capacious nature of spinal canal at the C1 level myelopathic symptoms hyperreflexia (patellar tendon reflex) muscles weakness broad based gait decreased hand dexterity loss of motor milestones bladder problems Imaging Radiographs flexion-extension xrays atlanto-dens interval (ADI) measurement distance between odontoid process and the posterior border of the anterior arch of the atlas adult parameters > 3.5mm considered unstable > 10mm indicates surgery in RA other must get preoperative flexion-extension radiographs to clear all high-risk patients for any type of surgery space-available-cord (SAC) = posterior atlanto-dens-interval (PADI) measurement distance from posterior surface of dens to anterior surface of posterior arch of atlas adult parameters in adults with RA < 14 mm associated with increased risk of neurologic injury and is an indication for surgery open mouth odontoid sum of lateral mass displacement measurement lateral mass are connect by ring of C1, and therefore can only be displaced relative to each other if there is a bony fracture (disruption of the ring) the transverse ligament is ruptured transverse ligaments binds them together adult parameters if > 8.1 mm, then a transverse ligament rupture is assured and the injury pattern is considered unstable Treatment Determined by specific condition adult atlantoaxial instability Down's syndrome Rheumatoid Arthritis Os odontoideum Odontoid fracture Atlas fractures Transverse ligament injuries pediatric atlantoaxial instability JRA Morquio's Syndrome Rotatory atlantoaxial subluxation
QUESTIONS 1 of 1 1 Previous Next (OBQ09.111) An 11-year-old male complains of one year duration of neck pain. He denies any recent trauma. He has noticed intermittent episodes of gait imbalance and difficulty with buttoning his shirt over the past 3 months. Physical exam shows normal strength in all four extremities and hyper-reflexic patellar tendons. Neutral and flexion radiographs are shown in Figures A and B. A sagittal CT scan is shown in Figure C with a coronal reconstruction shown in Figure D. What is the most appropriate treatment? QID: 2924 FIGURES: A B C D Type & Select Correct Answer 1 PT to strengthen the dynamic stabilizers of the neck 5% (252/5385) 2 Soft collar wear during any athletic activities 1% (30/5385) 3 Cessation of all contact sports with no surgical intervention 11% (601/5385) 4 Posterior C1-C2 fusion 76% (4083/5385) 5 Anterior C1-2 fusion 7% (394/5385) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
All Videos (1) Podcasts (1) Login to View Community Videos Login to View Community Videos C1-C2 Fixation with lateral masses and pedicular screws and rods and use of titanium cages Gustavo Azevedo Spine - Atlantoaxial Instability E 7/27/2012 750 views 1.5 (6) Spine | Atlantoaxial Instability Spine - Atlantoaxial Instability Listen Now 7:15 min 7/12/2022 150 plays 5.0 (1)