A new classification design of spinal tuberculosis, reliability analysis and treatment considerations

English Keywords:Spinal tuberculosis  Classification  Reliability assessment  Surgical treatment

English Abstract:

  【Abstract】 Objectives: To retrospectively review the clinical data from multiple centers of patients diagnosed with spinal tuberculosis, and identify key indicators that reflect the disease′s characteristics and clinical management to propose a novel classification system for spinal tuberculosis; To summarize the surgical treatment methods and outcomes of patients with complete data who were followed up for more than 1 year for surgical efficacy evaluation. Methods: The clinical data of 358 spinal tuberculosis patients diagnosed and treated at multiple centers between January 2007 and December 2022 were collected and analyzed. The patients aged 35.5±28.9 years old, and were consisted of 189 males and 169 females. There were 346 cases of active spinal tuberculosis and 12 cases of inactive tuberculosis. The distribution of lesion sites included cervical spine in 37 cases, cervicothoracic spine in 24 cases, thoracic spine in 126 cases, thoracolumbar spine in 79 cases, lumbar spine in 63 cases, and lumbosacral spine in 29 cases. The number of affected vertebrae per lesion was 3.1±1.9(ranged from 1 to 12). Clinical manifestations included pain, limited mobility, fever, elevated erythrocyte sedimentation rate, destruction and absorption of vertebrae and intervertebral discs, cold abscesses, and sequestra. Among the patients, 256 patients exhibited concomitant kyphotic deformities, and 66 patients presented with varying degrees of spinal cord or nerve dysfunction. Using expert panel discussions and opinion surveys, indicators that reflect the characteristics of spinal tuberculosis were identified and subjected to correlation analysis with the degrees of kyphosis. Based on these findings, a new comprehensive classification system(ASM classification) grounded in key indicators was designed and then re-evaluated and tested for reliability. In parallel, the clinical data of 117 patients with over one year of postoperative follow-up and complete records were collected, and the surgical efficacy was assessed according to visual analogue scale(VAS) score for pain, examination of spinal cord or nerve function, and measurement of Cobb angle of kyphosis as well as evaluation of graft fusion conditions on X-ray and CT. Results: The expert discussions confirmed that pathological stage, lesion location, number of affected vertebrae, and the presence of kyphotic deformity and spinal cord or nerve dysfunction were key indicators in the diagnosis and treatment of spinal tuberculosis; Other indicators such as the extent of vertebral destruction, segmental instability, and the number and size of sequestra and cold abscesses were found to be less specific. Correlation analysis demonstrated a significant association between kyphotic deformity and factors such as disease duration, lesion location, affected segment, and spinal cord or nerve involvement(P<0.05). Based on the validation results, a new comprehensive classification system was proposed. The spinal tuberculosis was categorized into two main types based on lesion activity, the active spinal tuberculosis(type Ⅰ) and inactive spinal tuberculosis(type Ⅱ). Type Ⅰ was further divided into four subtypes: type A - early-stage spinal tuberculosis, type B - progressive spinal tuberculosis, type C - special type including skip lesions, and type D - spinal appendage tuberculosis; Type Ⅱ was divided into two subtypes: type A - deformity-stable type, type B- deformity-progressive type. Additionally, the four key indicators-lesion location, number of affected vertebrae, presence and degree of kyphotic deformity, and spinal cord or nerve impairment were included as auxiliary indicators. Reliability analysis showed that the new classification system had good consistency and reproducibility. Among the 117 patients with over one year of postoperative follow-up and complete records, 12 with cervical tuberculosis underwent anterior approach surgery, 104 patients with lesions below the cervicothoracic junction underwent posterior-only surgery, and 1 thoracolumbar case underwent additional debridement of a cold abscess via a small contralateral abdominal incision during posterior surgery. Follow-up results revealed: VAS score was 1.9±0.3(1-3), kyphotic Cobb angle was 15.61°±8.44°(4°-40°); The patients with abnormal spinal cord nerve function were fully recovered to normal at the final follow-up, and the above-mentioned indicators were improved with statistically significant differences comparing with the preoperative values(P<0.05); 111 patients were clinically cured and bony fused on CT images; 6 patients experienced tuberculosis recurrence, among which, 5 failed in internal fixation due to graft non-fusion and underwent re-operation. Conclusions: The new classification system(ASM) effectively captures the clinical characteristics of spinal tuberculosis and facilitates diagnosis, treatment planning, and clinical communication. For patients with spinal tuberculosis below the cervicothoracic junction, a purely posterior surgical approach also represents an advantageous treatment option.