Radiological imaging characteristics and the clinical significance of sacrum and vertebra below the lumbar hemivertebra

English Keywords:Congenital scoliosis  Lumbar  Hemivertebra  Radiological imaging

English Abstract:

  【Abstract】 Objectives: To analyze the radiological imaging characteristics of sacrum and vertebra below lumbar hemivertebra in congenital scoliosis, and to provide data for the decision of distal fusion level. Methods: The preoperative radiographs were retrospectively reviewed in 93 patients(46 males and 47 females) with lumbar hemivertebra who underwent surgeries. The average age was 10.5±7.2 years(range, 2-42). All cases had routine radiographs and 3-D CT scan of the whole spine. Segmental scoliosis and kyphosis Cobb angle, coronal and sagittal balance were measured. Tilting of L4, L5 and S1 on standing anteroposterior and concave bending films were measured and the flexibilities of L4 and L5 were calculated. The indexes among 3 groups were also statistically analyzed by using SPSS 19.0 software. P value less than 0.05 was considered as statistically significant. Results: There was 1 hemivertebra in 88 patients and 2 hemivertebrae in 5 patients. 55 were fully segmented and 43 were semi-segmented. The mean local scoliotic curve was 42.5°±15.9°(range, 12°-93°) and flexibility was (26.6±17.9)%(range, 0-90%). The mean apical translation was 22.4±14.5mm(range, 2-72). 51 cases had focal kyphosis and the mean Cobb angle were 20.5°±20.3°(range, 2°-94°). 13 cases had coronal decompensation and 19 cases had sagittal imbalance. The mean tilting of L4, L5 and S1 on standing films was 23.5°±10.2°, 17.2°±9.0° and 9.8°±5.9° respectively. There were 18 cases in which the tilting of S1 equal to or greater than 15°, and 5 cases in which the tilting of S1 equal to or greater than 20°. The mean tilting of L4 and L5 on concave bending films was 14.5°±10.6° and 12.0°0±8.8° respectively. The mean flexibility of L4 and L5 was (43.44±29.1)% and (39.3±29.5)% respectively. The mean tilting on bending films and flexibility of L4 in 3 groups(A, age≤6 years; B, age between 7 to 12 years and C, age≥13 years) were 7.6°±6.6° and (59.11±34.0)%, 13.9°±10.5° and (42.9±25.7)%, 21.1°±9.8° and (31.4±22.0)%, respectively. The mean tilting on bending films and flexibility of L5 in 3 groups were 7.0°±6.6° and (41.8±33.8)%, 11.1°±8.5° and (39.1±23.4)%, 17.2°±8.7° and (25.6±21.9)%, respectively. The mean tilting on bending films and flexibility of L4 and L5 among 3 groups had statistical significances(P<0.05). Conclusions: Lumbar hemivertebra often causes tilting of the vertebra below it. The tilting of L4, L5 on bending films increase with age while flexibility decrease with age. The preoperative measurement of L4, L5 and S1 tilting and flexibility of L4 and L5 are very important for the decision of distal fusion level.