Evaluation and clinical application of a new classification system for Kümmell disease

English Keywords:Kümmell disease  Classification system  Treatment  Clinical application

English Abstract:

  【Abstract】 Objectives: To propose a new system for classifying Kümmell disease, and to evaluate its feasibility for guiding clinical treatment. Methods: A retrospective study of 168 cases of Kümmell disease with complete follow-up data was conducted at our institute. Patients were divided into type Ⅰ-Ⅴ based on a combination of clinical manifestations and different morphological changes detected by imaging. Type Ⅰ was characterized by bone non-union imaging, percutaneous vertebroplasty(PVP) was the primary treatment option for this basic imaging morphological change in Kümmell disease. Type Ⅱ was characterized by instability imaging, posterior fixation and fusion was the primary treatment option. Type Ⅲ was characterized by spinal stenosis imaging, the primary treatment option was posterior decompression fixation and fusion. Type Ⅳ was characterized by kyphosis imaging, the primary treatment option was posterior osteotomy, fixation, and fusion. Type Ⅴ was characterized by a combination of 3 or 4 of the above imaging signs, the treatment provided was related to the specific responsible types. Treatment outcomes were evaluated based on postoperative visual analogue scale(VAS) and Oswestry disability index(ODI) scores. During the follow-up period, it was observed whether the damaged vertebra exhibited compression or local secondary kyphosis and whether neurological function improved in patients accompanying with neurological symptoms. Results: Each patient received between 12-54(mean, 28.4±4.6) months of follow-up. Patients of each type had statistically significant improvements in postoperative VAS and ODI scores compared with preoperative scores. The VAS scores of type Ⅰ-Ⅴ patients improved from preoperative 8.0±1.7, 8.2±1.6, 8.4±1.4, 7.9±1.2 and 8.5±1.3 points respectively, to the final follow-up of 2.1±1.3, 2.2±1.2, 2.3±1.4, 2.2±1.4, 2.3±1.5 points. And the ODI scores of type Ⅰ-Ⅴpatients improved from preoperative 69.5±2.8, 68.5±2.6, 69.7±2.2, 65.6±2.7 and 68.6±2.7 respectively, to the final follow-up of 38.1±1.5, 37.1±1.3, 34.1±1.3, 35.2±1.4, 33.1±2.1 points. The difference was statistically significant(P＜0.05). During the follow-up period, 19 patients(11.3%) exhibited compression of damaged vertebra or local secondary kyphotic deformity. At the final follow-up of patients with neurological deficits, the American Spinal Injury Association(ASIA) grade of C in 12 patients improved to grade D in 3 cases, grade E in 9 cases, and 3 patients of grade D all improved to grade E. Conclusions: This new classification of Kümmell disease in type Ⅰ-Ⅴ is objective, simple and easy to perform, and can effectively guide clinical treatment.