Mu Qiao1,2, Bang-Ping Qian3,4, Yong Qiu1,2, Sai-Hu Mao1,2, Yi-Hua Wang1,2. 1. From Spine Surgery, and the Department of Pathology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School; Medical School of Southeast University, Nanjing, China. 2. M. Qiao, MD, Spine Surgery, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, and Medical School of Southeast University; B.P. Qian, MD, Spine Surgery, Drum Tower Hospital of Nanjing University Medical School; Y. Qiu, MD, Spine Surgery, Drum Tower Hospital of Nanjing University Medical School; S.H. Mao, MD, Spine Surgery, Drum Tower Hospital of Nanjing University Medical School; Y.H. Wang, MD, Department of Pathology, Drum Tower Hospital of Nanjing University Medical School. 3. From Spine Surgery, and the Department of Pathology, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School; Medical School of Southeast University, Nanjing, China. qianbangping@163.com. 4. M. Qiao, MD, Spine Surgery, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, and Medical School of Southeast University; B.P. Qian, MD, Spine Surgery, Drum Tower Hospital of Nanjing University Medical School; Y. Qiu, MD, Spine Surgery, Drum Tower Hospital of Nanjing University Medical School; S.H. Mao, MD, Spine Surgery, Drum Tower Hospital of Nanjing University Medical School; Y.H. Wang, MD, Department of Pathology, Drum Tower Hospital of Nanjing University Medical School. qianbangping@163.com.
Abstract
OBJECTIVE: To investigate the pathogenesis of pseudarthrosis in ankylosing spondylitis (AS) based on the pathological analysis of specimens harvested during surgery. METHODS: Radiographic and clinical data for 17 consecutive AS patients with pseudarthrosis were retrospectively analyzed. Meanwhile, the pathological analysis of specimens obtained during surgery was also performed. RESULTS: In total, 18 extensive Andersson lesions were included. Pseudarthrosis located at the apical region were noted in 12 patients. Complete ossified anterior longitudinal ligaments above or below pseudarthrosis and fracture through posterior elements or facet joints were observed in 7 and 6 lesions, respectively. The most definitive pathological characteristic in all cases was proliferating hypovascular edematous fibrous tissue involving disc, bone-disc border, and vertebral body. Fibrinoid necrosis, necrotic bone fragments, hemosiderin deposits, and active subchondral osteogenesis were found, indicating trauma process. Mild perivascular collections of inflammatory cells were detected in only 2 cases. CONCLUSION: AS-related pseudarthrosis is more likely to originate from mechanical trauma than inflammation. The above-mentioned radiological and histological findings showed that multiple mechanisms lead to the formation of pseudarthrosis. These mechanisms include excessive stress, insufficiency fracture, and an acute fracture involving a 3-column structure.
OBJECTIVE: To investigate the pathogenesis of pseudarthrosis in ankylosing spondylitis (AS) based on the pathological analysis of specimens harvested during surgery. METHODS: Radiographic and clinical data for 17 consecutive AS patients with pseudarthrosis were retrospectively analyzed. Meanwhile, the pathological analysis of specimens obtained during surgery was also performed. RESULTS: In total, 18 extensive Andersson lesions were included. Pseudarthrosis located at the apical region were noted in 12 patients. Complete ossified anterior longitudinal ligaments above or below pseudarthrosis and fracture through posterior elements or facet joints were observed in 7 and 6 lesions, respectively. The most definitive pathological characteristic in all cases was proliferating hypovascular edematous fibrous tissue involving disc, bone-disc border, and vertebral body. Fibrinoid necrosis, necrotic bone fragments, hemosiderin deposits, and active subchondral osteogenesis were found, indicating trauma process. Mild perivascular collections of inflammatory cells were detected in only 2 cases. CONCLUSION: AS-related pseudarthrosis is more likely to originate from mechanical trauma than inflammation. The above-mentioned radiological and histological findings showed that multiple mechanisms lead to the formation of pseudarthrosis. These mechanisms include excessive stress, insufficiency fracture, and an acute fracture involving a 3-column structure.