Spondylodiscitis in kyphotic deformity of ankylosing spondylitis and its healing affected by dorsal correction osteotomies. Report of 33 patients

Out of 144 patients with kyphotic deformities in Ankylosing spondylitis 33 (23%) had 45 disco-vertebral lesions of the spondylodiscitic type. They were characterized by osteolyses, scleroses and absence of syndesmophytes. 5 had additional arch fractures. All were localized in or below the apical vertebra in the lumber or the lower thoracic spine. Compared with the total collective strong pain, high sedimentation rates and extravertebral manifestations were more frequent, osteoporosis rare, and the degree of kyphosis and the types of ossification same. The radiology showed the lesions as inflammatory etiology. Functionally, however, they are pseudarthroses. All spines were lordosed by dorsal osteotomies and therewith statically corrected and for one year externally immobilized. The spondylodeses fusioned in this time. Complications did not occur on account of the spondylodiscites. The therapy of kyphosis had an influence on the spondylodiscites. They all healed except for one. After a follow up of two years 98% were completely fused, also those with non-identical levels of correction and lesion. The loss of correction in the segments of lesion was negligibly more than in the total collective. 91% of the patients were pain-free compared to 12% preoperatively. The spondylodiscites were no hindrance for dorsal lordosing osteotomies and can be treated successfully by means of this static correction and the immobilisation.