Spino-pelvic alignment in patients with spinal deformity secondary to Marfan syndrome

English Keywords:Marfan syndrome  Spinal deformity  Sagittal  Pelvis

English Abstract:

  【Abstract】 Objectives: To investigate the spino-pelvic alignment in Marfan syndrome patients. Methods: A retrospective study was performed on 35 patients with spinal deformity secondary to Marfan syndrome(18 males and 17 females), the average age was 14.4±2.3 years(10-20). The following spinal and pelvic parameters were measured on the standing lateral radiographs of the whole spine: (1)thoracic kyphosis(TK), (2)thoracolumbar kyphosis(TL), (3)lumbar lodorsis(LL), (4)pelvic incidence(PI), (5)pelvic tilt(PT), (6)sacral slope(SS), (7)sagittal vertical axis(SVA). The thoracolumbar kyphosis was defined as the kyphosis Cobb angle larger than 10° and the apex sitting at T12, L1 or T12/L1 disc; the lumbar kyphosis was defined as the kyphosis Cobb angle larger than 10° and the apex below L1/2 disc. The patients were divided into two groups according to Sponseller′s classification, and the spino-pelvic parameters were compared between two groups. Results: In the frontal plane, the most common curve types were double major(40.0%), thoracic(22.8%) and triple(20.0%), and the mean maximum Cobb angle was 75.2°±26.0°(43°-165°). In the sagittal plane of the spine, the TK was 19.0°±24.1°(-25°-73°), 28.6%(10/35) for normal thoracic kyphosis(20°≤TK≤50°), 14.3%(5/35) for hyperkyphosis(TK>50°), 37.1%(13/35) for hypokyphosis(0°≤TK<20°), and 20.0%(7/35) for thoracic lordosis. TL was 14.0°±19.0°(-25°-73°); LL was 37.1°±23.3°(-17°-70°); SVA was -9.0-7.2cm(-2.0±4.3cm). According to our definition, 42.9%(15/35, 9 type ⅡA, 6 type ⅡB) of cases had thoracolumbar kyphosis or lumbar kyphosis, and 5 presented with vertebral wedging. In the sagittal plane of the pelvis, PI was 40.1°±12.7°(25°-74°)； PT was 6.9°±9.6°(-12°-34°); SS was 33.3°±12.6°(14°-68°). Type Ⅰ had larger TK, LL, PI, SS than type Ⅱ, while type Ⅱ had larger TL and PT than type Ⅰ. Furthermore, there was no spondylolisthesis occurred in this series. Conclusions: The patients with Marfan syndrome differ greatly in the spino-pelvic alignments, which indicate different surgical strategies according to different spino-pelvic alignments.