Syringomyelia with irreducible atlantoaxial dislocation, basilar invagination and Chiari I malformation

Abstract

A 27-year-old woman presented with bilateral weakness of her all extremities for 5 years. She had a spastic gait and was unable to ambulate without assistance. Neurologic examination revealed increased deep tendon reflexes and positive pathologic reflexes. Radiographs showed occipitalization of the atlas, C2-C3 congenital fusion and fixed atlantoaxial dislocation with an atlanto-dental interval of 10 mm. MRI demonstrated cervicomedullary junction (CMJ) compression from the odontoid, a Chiari type I malformation, and syringomyelia extending from the foramen magnum to C5. The patient underwent transoral atlantoaxial release followed by posterior internal fixation from the occiput to the axis, which resulted in a significant improvement in motor function in all extremities. Postoperative images showed anatomical reduction of the atlantoaxial joint. However, an MRI performed 8 days following surgery showed a new retro-odontoid pannus had developed that was compressing the spinal cord at CMJ. A follow-up CT scan performed at 6 months post-operatively demonstrated a solid bony fusion between the occiput and C2, while an MRI at that time showed complete resolution of the retro-odontoid soft tissue mass with correction of the Chiari I malformation, and resolution of the syringomyelia. Final follow-up at 2-years revealed an excellent clinical outcome.Keywords Syringomyelia Á Irreducible atlantoaxial dislocation Á Basilar invagination Á Surgery Á Transoral release Case presentationA 27-year-old woman presented with a 5-year history of progressive weakness and numbness that began in her right extremities. Her symptoms progressed rapidly for the first year and eventually her entire right side became involved. When admitted, she complained of an unsteady gait requiring an assistive device to ambulate, and lacked coordination in her hands (impossible to button up her shirt). Neurologic examination of the lower extremities revealed normal sensation to light touch, pain and temperature, while sensory dysfunction of the upper limbs was present. Symmetrical hyperreflexia, as well as positive Hoffman's and Babinski signs were present bilaterally. Weakness was present on both sides, with the right side being more severe. Her gait was wide-based, spastic, and unsteady. She also had limited range of motion on cervical

Difficulties in distinguishing between an atlas fracture and a congenital posterior atlas arch defect in postmortem analysis

“…In addition, Chari malformation [21] and thalassemia minor [22] have also been related to atlas deformities. However, the medical history of the cadaver from which the vertebra was obtained made no mention of those syndromes, thus the anatomical variations would have been caused by a pre-mortem injury or during post-mortem handling of the specimen.…”

Cable-Strengthened C2 Pedicle Screw Fixation in the Treatment of Congenital C2-3 Fusion, Atlas Occipitalization, and Atlantoaxial Dislocation

“…Dissection of the bilateral longus coli and longus capitis muscles and the anterior longitudinal ligament was performed, followed by partial resection of the C1 anterior arch. 4,8 The alar and apical ligaments were also resected to obtain sufficient release. The release procedure was deemed complete when the C1 anterior arch could be levered up to the tip of the dens to achieve the anatomic reduction of the AAD ( Figure 3).…”

“…Shen et al 1 also found that patients with occipitalization and congenital C2-3 fusion tended to have greater anterior atlantodens interval values than others. These patients often have cervical myelopathy or concomitant anomalies such as basilar invagination, secondary Chiari I malformation, and syringomyelia 3,4 and need occipitocervical reduction and fixation. In the literature, posterior occiput-C2 fixation using C2 pedicle screws (C2PSs) has been widely reported and shown to be effective.…”

Retropharyngeal Reduction Plate for Treatment of Irreducible Atlantoaxial Dislocation: A Cadaveric Test and Finite Element Analysis

“…Consequently, if AAD is not treated in a timely and appropriate manner, the displacement may become irreversible [1][2][3][4]. If observation of the dynamic X-ray shows that the reduction of the atlantoaxial joint failed with skeletal traction under general anesthesia, AAD is considered irreducible [5]. To date, available treatments for IAAD are posterior decompression, anterior release via transoral approach followed by posterior xation, and transoral atlantoaxial reduction plate (TARP) internal xation, to name a few [6][7][8].…”