Case report. Transoral surgery for myelopathy caused by rheumatoid arthritis of the cervical spine.

Spontaneous forward luxation at the atlanto-axial level is a well-known and common complication of rheumatoid arthritis. The distance between the articular surface of the odontoid process of the axis and the corresponding articular surface of the atlas should not normally exceed 3 mm. in adults; a larger distance indicates luxation. Conlon, Isdale. and Rose (1966) found luxation between atlas and axis in 25 per cent. of 333 consecutive patients of rheumatoid arthritis. Luxation at this level initially leads to compression of occipital nerve roots causing radiating pain in the occipital region. Increasing luxation is known to result in medullary or arterial compression with severe neurological deficit and the outcome may be fatal. Smith, Benn, and Sharp (1972) found that 30 of 150 patients with atlanto-axial luxation already had signs of medullary and/or arterial compression or developed them during the period of observation. The surgical treatment of atlanto-axial luxation in rheumatoid arthritis thus seems well justified. The method of choice seems to be posterior exposure, reposition, and fusion between the occiput and the cranial part of the cervical spine. Fusion with bone grafts only entails prolonged immobilization, which may be harmful, particularly in a patient with rheumatoid arthritis. Over the last 3 years we have treated eleven patients with rheumatoid atlanto-axial luxation, using a technique permitting early mobilization, Our results are encouraging and have been reported elsewhere (Brattstrom and Granholm, 1973). The method used is a further development of the technique described by Scoville, Palmer, Samra and Chong (1967) for metastatic disease of the spine and requires the use of wire, acrylic plastic, and bone chips to obtain fixation and fusion. The prerequisite for this forward atlanto-axial luxation is a destruction of the ligaments between Cl and C2. Rheumatoid arthritis may, however, cause a much more wide-spread lesion in adjacent bone, mainly in the joint facets, leading to a downwards luxation of the atlas on the axis. Smith and others (1972) found downwards luxation in nine of their 150 cases of rheumatoid atlanto-axial luxation. In this condition, the odontoid process may protrude through the foramen magnum and further reduce the space for the spinal cord. In one case recently treated by us this complication resulted in paraplegia due to pressure on the medullary structures intracranially. This case is of interest, not only because this complication may not be too uncommon, but also because such patients may be treated surgically. In the case described below, the odontoid process was first removed by a transoral route, and fixation of the occiput to the cervical spine was then achieved in a second procedure.