Analysis of delayed infection of proximal junctional zone after posterior spinal internal fixation and its treatment strategy

OBJECTIVE: To explore the features and treatment strategy of delayed infection of proximal junctional zone after posterior spinal internal fixation. METHODS: The clinical data of 1325 patients underwent posterior spinal internal fixation were retrospectively analyzed. Delayed infection occurred in 10 patients, among which 4 infections occurred at the proximal junction (non-operative site). And these 4 patients were treated with combined broad-spectrum antibiotics. Their clinical symptoms and signs, lab tests, MRI findings, pathology findings, and clinical effects were analyzed. RESULTS: All four patients were followed up from 6 months to 4 years. No infection recurrence was found. All patients obtained satisfactory results after hospital discharge. No nerve injury was found. One patient developed kyphosis in the proximal junctional zone 2 years after the operation. According to the criteria of N.Nakano and T.Nakano, 3 cases obtained excellent results, while 1 poor. CONCLUSIONS: The incidence rate of delayed infections was rare after spinal operation. Delayed infections occurred in proximal junctional zone may be attributed to the stress concentration of adjacent segments after fixation and the degeneration of adjacent segments, thus forming inflammation areas. For refractory lumbar and back pains, an elevated blood sedimentation rate, C-reactive protein level, MRI manifestation and focal pathology would be helpful for establishing a definite diagnosis. Full course of combined broad-spectrum antibiotics in treating the infection can lead to satisfactory clinical results.