Title: Basilar invagination. An uncommon complication of long standing Rheumatoid Arthritis
Patricia Harkins,Qutab Shah, Aine Gorman, Deniz Demirdal, Angela Camon, Ausaf Mohammad, Killian O’Rourke
Department of Rheumatology Midland regional Hospital Tullamore
Basilar invagination is defined as an abnormality of the craniovertebral junction in which the odontoid process of the second cervical vertebrae prolapses into the already narrow opening of the foramen magnum. This can result in a plethora of neurological symptoms secondary to compression of the brain stem as it exits the cranium. In recent times it is a rare complication of rheumatoid arthritis due to the introduction of Disease Modifying anti-rheumatoid drugs (DMARDS).
We present the case of a 72 year old lady with a 31 year background of erosive sero-positive ,anti-CCP positive, destructive, deforming rheumatoid arthritis who presented to clinic complaining of new onset bilateral hand numbness from the wrist to the fingertips. Examination proved difficult due to severe deformities, contractures and longstanding peripheral neuropathy. Within these limits, there was reduced power on shoulder abduction bilaterally, altered sensation in hands and feet bilaterally and hyper-reflexia at the supinator and biceps tendon. Hoffmans test was negative. Continence was preserved, and there were no cerebellar signs and cranial nerve examination was entirely intact.
An urgent MRI brain and Cervical-Spine was ordered which demonstrated marked multilevel secondary degenerative changes and ankylosis of the cervical spine. Of particular interest there was evidence of basilar invagination with proximal migration of the odontoid process causing a marked narrowing of the foramen magnum and significant compression of the cervical cord at this level. She await consideration for considered for surgical intervention
Rheumatoid arthritis of the C-Spine was first described by Garrod in 1890. Classically it had a variety of pathological manifestations, namely atlantoaxial subluxation, basilar invagination and subaxial subluxation. In recent years however, the advent of synthetic and biologic DMARDs has resulted in a dramatic decrease in the incidence and severity of rheumatic spinal disease, such that the above complications are now rarely encountered in clinical practice. Surgical management of this rare complication in RA is complex given the high likelihood of a comorbid patient, on long-term steroids and immunosuppression –all of which increase the operative risk. It requires input from all members of the MDT to maximize patient outcome.