850 zyxwvutsrq BRIEF REPORTS zyxwvuts HANGMAN’S FRACTURE IN ANKYLOSING SPONDYLITIS PRECEDED BY VERTICAL SUBLUXATION OF THE AXIS MURRAY BARON, CHARLES H. TATOR, and HUGH LITTLE Vertical subluxation of the axis is rare in anky- losing spondylitis (AS) and has been reported in only two previous cases zyxwvutsr (1,2). Forward subluxation of the atlas on the axis is the abnormality of the upper cervical spine which has been more commonly described (3-5). Spinal fractures are a well recognized complica- tion of ankylosing spondylitis. Hunter (6) recently re- viewed spinal fractures in ankylosing spondylitis and found 56 previously reported cases. He added 8 unre- ported cases of his own and from the total of 64 cases, only 8 fractures occurred in the upper cervical spine. None of these fractures were above C3 (7). We describe here a patient with ankylosing spondylitis and vertical subluxation of the axis who sub- sequently suffered a fracture of the neural arch of C2. It is possible that the preexisting vertical sub- luxation of the axis predisposed to the unusual fracture of C2 in a patient with ankylosing spondylitis. This complication of vertical subluxation of the axis has not been reported previously. CASE REPORT KH, a 65-year-old white woman with ankylosing spondylitis, first developed low back stiffness in her mid-teens. Over the ensuing 20 years, she experienced progressive involvement of the entire axial spine. In 1969 radiographs showed typical late stage fusion of the sacroiliac joints (Figure 1) and of the lumbar and lower From the Department of Medicine and Neurosurgery, Sunnybrook Medical Centre, University of Toronto, Toronto, On- tario. Murray Baron, MD, FRCP(C); Charles H. Tator, PhD, FACS, FRCS(C); Hugh Little, MD, FRCP(C). Address reprint requests to Dr. Hugh Little, Sunnybrook Medical Centre, 2075 Bayview Avenue, Toronto, Ontario, Canada M4N 3M5. Submitted for publication November 26, 1979; accepted in revised form February 19, 1980. cervical spine. The atlas, however, was in a normal rela- tionship to the occiput and to C2 (Figure 2). Peripheral joint involvement was limited to occa- sional stiffness of her shoulders and knees. She experi- enced multiple bouts of acute iritis which required treat- ment with local corticosteroids and which led to the development of secondary glaucoma. There was no his- tory of skin rash, bowel disease, or any illness other than occasional “fainting spells” which developed in the early 1970s. The patient noted that these fainting spells consisted of suddenly falling to the floor without prior warning. She was uncertain whether there was loss of consciousness but noted that there were no other ac- companying neurologic symptoms. There was no pro- drome or aura. No incontinence occurred and she was always able to get up quickly. She did not experience palpitations, and electrocardiograms had always been normal. In 1974 she fractured the left hip and in 1975 the right, after falling during her fainting spells. In September 1977 she first developed severe un- relenting neck pain with radiation to the posterior occi- put bilaterally. Examination revealed marked limitation of range of motion of the cervical spine with only 10 de- grees of lateral rotation to either side. Radiographs (Figure 3) showed a severe change since 1969; the axis had subluxed vertically through the atlas and the odon- toid process was projecting into the foramen magnum. The nerve roots of C2 and C2-C3 synovial joints were infiltrated with xylocaine resulting in complete but tem- porary relief of pain. In August 1978 she fell backward, striking the occiput on the foot of a bed. She was unable to give an adequate description of the fall but it seems to have been preceded by one of her fainting spells. She lost consciousness for several minutes. When she first re- gained consciousness, she was unable to speak for about 5 minutes and could not move any of her extremities. Arthritis and Rheumatism, Vol. 23, No. 7 (July 1980)