Discussion on the Clinical and Radiological Aspects of Sacro-Iliac Disease

Abstract

It is unusual for the sacro-iliac joints to be spared in ankylosing spondylitis, although such cases do undoubtedly occur, and account for approximately 1% of all patients with the disease. Thus Hench et a. (1947) quote 9 such patients in a series of 1,035; Knuttson (1950) 1 patient in a series of 147; Forestier et al. (1956) 2 patients in a series of 200. In my own experience of 163 patients I have known 2 such cases. The first of these patients was a woman aged 52 years with a history of peripheral arthritis and spondylitis dating from the age of 32, associated with severe psoriasis. She was anaemic and debilitated, and had ankylosis of cervical, thoracic and lumbar spines, but the-sacro-iliac joints were unaffected. The second patient was a man aged 66 years who had suffered from a peripheral arthritis of the rheumatoid type for eighteen years. Classical spondylitic changes in the cervical region had developed later; the remainder of the spinal column and the sacro-iliac joints were spared. These occasional atypical examples of spondylitis can be distinguished, on radiological and clinical grounds, from the group classified by Forestier and Rotes-Querol (1950) as suffering from senile hyperostosis of the spine. Reference must also be made to senile changes in the sacro-iliac joints. Fibrous obliteration of these joints, occurring more or less as a normal phenomenon of advancing age, has been described (Romanus and Yden, 1955). This process leads to immobilization by intra-articular ankylosis. These changes alone do not result in radiographic obliteration of the joints, but only in narrowing of the joint space. The diagnosis of senile obliteration of the sacro-iliac joints should not be considered until full clinical and radiological evidences of spondylitis have been sought and proved absent. In ankylosing spondylitis, sacro-iliac and vertebral symptoms may be slight, and indeed gross changes leading to complete synostosis of the joints may occur in the total absence of symptoms: A miner, aged 31 years, was admitted to hospital suffering from a dislocated femur as the result of a motorcycle accident. X-ray of the pelvis revealed complete synostosis of the sacro-iliac joints due to ankylosing spondylitis. Further X-rays of the remainder of the spine revealed a "poker-spine" with gross syndesmophyte formation. This patient had worked uninterruptedly as a coal-hewer in low pit seams. The only features of note in his previous medical history were an episode of duodenal type of dyspepsia and an illness characterized by gross anemia, refractory to oral iron, but which responded to intravenous iron.