Korovessis Panagiotis, Zacharatos Spyridon, Repantis Thomas, Michael Andreas, Karachalios Dionysios
Orthopaedic Department of General Hospital Agios Andreas, Patras, Greece.
J Spinal Disord Tech. 2008 Jun;21(4):293-8. doi: 10.1097/BSD.0b013e31812e6295.
Prospective controlled cohort study of 27 adult osteoporotic patients who underwent kyphoplasty for fresh osteoporotic spinal fractures.
To define the evolution of vertebral bone mineral density (BMD) at kyphoplasty and adjacent levels along with sagittal spinal alignment to contribute to the etiology of adjacent vertebral fractures after augmentation.
Osteoporotic compression fractures can be effectively treated with methylmethacrylate vertebral augmentation. However, to the authors' knowledge the effect of vertebral augmentation on the vertebral endplate BMD of the augmented and adjacent nonaugmented levels has not as yet been described.
Twenty-seven consecutive selected patients (9 men, 18 women), with an average age of 72+/-9 years underwent 1, 2, or 3-level percutaneous kyphoplasty for painful fresh osteoporotic vertebral fractures at the thoracolumbar spine. All patients were radiologically examined with plain roentgenograms, computed tomography, and magnetic resonance imaging. Lateral dual energy x-ray absorptiometry in the augmented and on the adjacent vertebrae (1 level above and below kyphoplasty) was used to measure BMD preoperatively to the last postoperative observation in the subchondral bone of the vertebral endplates. Anthropometric data, sagittal global balance (plumbline), and segmental spine reconstruction (vertebral body height, Gardner kyphotic angle) were recorded and analyzed. The patients were followed for at least 2 years.
Kyphoplasty was performed between T12 and L5. A total of 48 vertebral bodies were augmented. Thirteen patients received 1 level and the remaining 14 received 2 or 3-level kyphoplasty. No significant changes in the sagittal spinal balance were shown postoperatively. Gardner kyphotic angle and posterior vertebral body height improved postoperatively, however, insignificantly. Significant [analysis of variance (ANOVA), P=0.008] increase of anterior vertebral body height in the fractured vertebra was achieved postoperatively without subsequent loss of correction. BMD increased significantly in the lower endplate of the augmented vertebra (ANOVA, P=0.05). In 1-level augmentation, no BMD changes were shown at the adjacent vertebrae above and below kyphoplasty. On the contrary, in the multilevel augmentation, a statistically significant (ANOVA, P=0.05) decrease of the BMD was shown in the upper endplate of the adjacent level above kyphoplasty. During the 2-year follow-up, there were 5 (18%) new fractures at the T11-T12 area above the augmented vertebra. All of the fractures occurred in patients who received 2 and 3-level kyphoplasty.
The observed 2-year evolution of vertebral endplate BMD, after kyphoplasty under stable global sagittal spinal balance, might contribute to the pathogenesis of new fractures in adjacent vertebra. However, other studies with control series and longer follow-up are necessary to show if these BMD changes are the result of vertebral augmentation or are merely natural history.
对27例因新鲜骨质疏松性脊柱骨折接受椎体后凸成形术的成年骨质疏松患者进行前瞻性对照队列研究。
确定椎体后凸成形术时及相邻节段椎体骨密度（BMD）的变化以及矢状面脊柱排列情况，以探讨强化术后相邻椎体骨折的病因。
骨质疏松性压缩骨折可通过甲基丙烯酸甲酯椎体强化术有效治疗。然而，据作者所知，椎体强化术对强化节段及相邻未强化节段椎体终板骨密度的影响尚未见报道。
连续选取27例患者（9例男性，18例女性），平均年龄72±9岁，因胸腰椎新鲜骨质疏松性椎体骨折疼痛接受1、2或3节段经皮椎体后凸成形术。所有患者均接受X线平片、计算机断层扫描和磁共振成像检查。采用侧位双能X线吸收法测量强化椎体及相邻椎体（椎体后凸成形术上下各1个节段）术前至术后最后一次观察时椎体终板软骨下骨的骨密度。记录并分析人体测量数据、矢状面整体平衡（铅垂线）和节段性脊柱重建情况（椎体高度、加德纳后凸角）。对患者进行至少2年的随访。
椎体后凸成形术在T12至L5节段进行。共强化48个椎体。13例患者接受1节段强化，其余14例接受2或3节段强化。术后矢状面脊柱平衡无明显变化。加德纳后凸角和椎体后缘高度术后有所改善，但不显著。术后骨折椎体的椎体前缘高度显著增加（方差分析，P = 0.008），且无后续矫正丢失。强化椎体下端板的骨密度显著增加（方差分析，P = 0.05）。在1节段强化中，椎体后凸成形术上下相邻椎体的骨密度无变化。相反，在多节段强化中，椎体后凸成形术上方相邻节段上端板的骨密度出现统计学显著下降（方差分析，P = 0.05）。在2年随访期间，强化椎体上方T11 - T12区域出现5例（18%）新发骨折。所有骨折均发生在接受2或3节段椎体后凸成形术的患者中。
在矢状面脊柱整体平衡稳定的情况下，观察到椎体后凸成形术后2年椎体终板骨密度的变化可能与相邻椎体新发骨折的发病机制有关。然而，需要其他有对照系列且随访时间更长的研究来确定这些骨密度变化是椎体强化术的结果还是仅仅是自然病程。
