5. DISCUSSION
The principle of surgical treatment for pyogenic spondylitis is curettage of the infected lesions with spinal fusion.5Anterior curettage and bone grafting combined with posterior instrumented fixation have demonstrated good results in maintaining local spinal alignment.6 However, a combined anterior and posterior approach is highly invasive. Thoracotomy has been reported to be strongly associated with respiratory complications,7 particularly in older patients. Because the patient in the present case was elderly and had a long history of pyothorax, the patient’s pleura and vessels were expected to be severely adhered to the vertebrae using the transthoracic approach, thereby increasing the difficulty and risk of surgery. Therefore, single-stage posterior fixation with PPS in combination with curettage of the vertebral bodies using the separated posterolateral approach was selected for treatment.
We previously reported a lateral rhachotomy and posterior spinal fusion with compression hooks for thoracic tuberculous spondylitis.3 The drawbacks of this method were relatively weak fixation compared to pedicle screw systems.8 PPS fixation is more rigid than the hook system. In addition, PPS is assumed to reduce the risk of instrument contamination compared to the hook system, which requires conventional spinal exposure. In an analysis of 10 reports of pyogenic spondylitis treated with single-stage debridement and spinal instrumentation using an open, identical approach, Przybylski et al.9reported that 7 out of 106 cases demonstrated recurrent infection. In the present case, spinal fixation with PPS and curettage were independent approaches. The PPS was placed closer than usual to the midline so that screw heads and rods were isolated from the infected lesion. A thick muscular septum between the posterior instruments and infected vertebral lesion is expected to prevent the instruments from bacterial contamination.