Percutaneous Endoscopic Surgery Alone to Treat Severe Infectious Spondylodiscitis in the Thoracolumbar Spine: A Reparative Mechanism of Spontaneous Spinal Arthrodesis.

Background: Infective spondylodiscitis has been treated solely with antibiotics based on the pathogen identified. Surgical intervention was used in cases of unidentified pathogens, failed antibiotic treatment, neurological deficit, or instability. The standard surgical procedure was debridement and interbody fusion with a bone graft through the anterior approach, followed by posterior instrumentation. Recently, percutaneous endoscopic surgery has been proven to be safe and effective for treating infectious spondylodiscitis. The results of endoscopy surgery treatment alone for infectious spondylodiscitis with severe bony destruction were analyzed in this study.

Objective: To describe the clinical and radiological outcomes in patients with infectious spondylodiscitis and severe bony destruction, who were treated with minimally invasive endoscopic surgery alone.

Study Design: Retrospective observational study (Institutional Review Board: CMUH 105-REC2-101).

Setting: An inpatient surgery center.

Methods: The study included 24 patients with infectious spondylodiscitis and severe bony destruction treated with endoscopy surgery. The patients were treated according to the endoscopic surgical protocol and were followed up for at least 5 years. A retrospective chart review was conducted to evaluate the locations, symptoms and signs, comorbidity, pain scale, and functional outcome. Laboratory data, such as erythrocyte sedimentation rate and C-reactive protein level, and clinical outcomes, including the pain scale, visual analogue scale, and functional score of Oswestry disability index, were recorded. All patients underwent a preoperative magnetic resonance imaging (MRI) scan and were carefully reviewed and classified based on the severity, including endplate erosion, bone edema (low T1, high T2), loss of vertebral height, paravertebral inflammation, paravertebral abscess, and epidural abscess. All patients underwent a plain film follow-up at 3, 6, 9, 12, and 18 months after surgery and computed tomography at 12 months postoperatively.

Results: The comorbidities of patients were categorized according to the Charlson Comorbidity Index. The results revealed 10 lesions on the thoracic or upper lumbar spine (between T10 and L3) and 14 on the lower lumbar spine (between L3 and S1). Bone destruction as a result of severe infection and loss of disc height was observed in most cases. During the final follow-up, no significant changes were observed in the sagittal alignment, and a kyphotic angle change of less than 10° was observed in 20 cases. Syndesmophyte formation along the anterior longitudinal ligament (ALL), paravertebral syndesmophyte formation, intervertebral bony fusion, and bony ankylosis of the facet joints in the form of osteophyte formation and fusion were noted. No posterior instrumentation surgery was performed for instability in our case series.

Limitations: This was a retrospective observational clinical case series with small sample size.

Conclusions: A trend of spontaneous spinal arthrodesis, including syndesmophyte formation along the ALL, paravertebral ligaments, direct intervertebral bone growth, and bony ankylosis of the facet joint were observed after a minimally invasive endoscopy treatment for infectious spondylodiscitis. The stability of the 3 columns resulted in segmental stability, which prevented the progression of the kyphotic deformity. Percutaneous endoscopic surgery is safe and effective for treating infectious spondylodiscitis even in patients with severe bony destruction.