The relationship between single-segment increased signal intensity on T2WI and the surgical results of thoracic ossification of the ligamentum flavum

English Keywords:Thoracic ossification of the ligamentum flavum  MRI T2WI  Increased signal intensity  Surgical results

English Abstract:

  【Abstract】 Objectives: To investigate the relationship between single-segment intramedullary increased signal intensity(ISI) on T2-weighted imaging(T2WI) and the surgical results of thoracic ossification of the ligamentum flavum. Methods: From January 2010 to December 2013, 59 patients with thoracic ossification of the ligamentum flavum underwent posterior decompression surgery with thinned-segmented decompression technique. ISI group included 28 patients, there were 18 males and 10 females with an average age of 52.8±1.8 years old(range, 43-63 years old). The average course of disease was 20.1±3.7 months(range, 11-38 months). 11 cases had spinal cord compression at single level, 7 cases at two levels, 6 cases at three levels, 4 cases at more than three levels. The average pre-operative JOA score was 4.8±1.6(range, 3-7). 2 cases were in ASIA grade B, 11 cases in grade C, 15 cases in grade D. Normal group included 31 patients, there were 20 males and 11 females with an average age of 53.7±2.4 years old(range, 38-66 years old). The average course of disease was 18.7±4.3 months(range, 5-38 months). 15 cases had spinal cord compression at single level, 9 cases at two levels, 5 cases at three levels, 2 cases at more than three levels. The average preoperative JOA score was 4.9±1.8(range, 3-8). 1 case was in ASIA grade B, 14 cases in grade C, 16 cases in grade D. The preoperative, postoperative JOA score, JOA score improvement rate and ASIA grade of each patient was evaluated. Results: All patients were followed up with an average time of 23.7 months (range from 6 to 54 months). All patients got bony fusion 6 months after operation. There was no internal fixation loosen and displacement. 2 patients suffered from neurological deterioration in ISI group, while 1 patient suffered from neurological deterioration in normal group. All of them healed after treatment. At last follow-up, the average JOA score of ISI group and normal group was 7.0±1.5(range, 6-10) and 8.9±1.1(range, 8-10), the average JOA improvement rate of two groups was (40.0±12.4)%(range, 28.3%-78.9%) and (53.7±15.4)%(range, 38.7%-83.1%). The last follow-up JOA score of two groups significantly improved compared with those of preoperative(P<0.05). The postoperative JOA score and improvement rate of ISI group were significantly lower than those of normal group(P<0.05). At last follow-up, ASIA grade of most patients in two groups improved compared with the preoperatives. Conclusions: For thoracic ossification of the ligamentum flavum with high signal intensity on T2W1, surgical treatment is a effective method, but less than that with normal signal intensity.