University of New Mexico, Carrie Tingley Hospital, 1127 University Boulevard NE, Albuquerque, NM 87102, USA.
Clin Orthop Relat Res. 2011 May;469(5):1253-7. doi: 10.1007/s11999-010-1634-8.
Patients with spina bifida frequently sustain lower extremity fractures which may be difficult to diagnose because they feel little or no pain, although the relative contributions of low bone density to pain insensitivity are unclear. Routine dual-energy xray absorptiometry (DXA) scanning is unreliable because these patients lack bony elements in the spine, and many have joint contractures and/or implanted hardware.
QUESTIONS/PURPOSES: We asked (1) if the lateral distal femoral scan is useful in spina bifida; (2) whether nonambulatory children with spina bifida exhibit differences in bone mineral density (BMD) compared with an age-and-sex-matched population; and (3) whether Z-scores were related to extremity fracture incidence.
We retrospectively reviewed 37 patients with spina bifida who had DXA scans and sufficient data. Z-scores were correlated with functional level, ambulatory status, body mass index, and fracture history.
The distal femoral scan could be performed in subjects for whom total body and/or lumbar scans could not be performed accurately. Twenty-four of 37 had Z-scores below -2 SD, defined as "low bone density for age." Ten of 35 patients (29%) with fracture information had experienced one or more fractures. Our sample size was too small to correlate Z-score with fracture.
We believe BMD should be monitored in patients with spina bifida; nonambulatory patients with spina bifida and those with other risk factors are more likely to have low bone density for age than unaffected individuals. The LDF scan was useful in this population in whom lumbar and total body scans are often invalidated by contracture or artifact. Although lower extremity fractures occur regardless of ambulation or bone density, knowing an individual's bone health status may lead to interventions to improve bone health.
患有脊柱裂的患者经常会发生下肢骨折，由于他们几乎或完全感觉不到疼痛，这些骨折可能难以诊断，尽管骨密度低导致的疼痛不敏感的相对贡献尚不清楚。常规的双能 X 射线吸收法（DXA）扫描不可靠，因为这些患者的脊柱缺乏骨性元素，而且许多患者有关节挛缩和/或植入的硬件。
问题/目的：我们询问了（1）外侧股骨远端扫描在脊柱裂中的作用；（2）是否非运动性脊柱裂儿童的骨矿物质密度（BMD）与年龄和性别匹配的人群存在差异；（3）Z 分数是否与四肢骨折的发生率有关。
我们回顾性分析了 37 例接受 DXA 扫描并有足够数据的脊柱裂患者。Z 分数与功能水平、运动状态、体重指数和骨折史相关。
对于不能准确进行全身和/或腰椎扫描的患者，可以进行股骨远端扫描。37 例中有 24 例 Z 分数低于-2 SD，定义为“年龄相关的低骨密度”。35 例有骨折信息的患者中有 10 例（29%）经历过一次或多次骨折。我们的样本量太小，无法将 Z 分数与骨折相关联。
我们认为应监测脊柱裂患者的 BMD；非运动性脊柱裂患者和有其他危险因素的患者比未受影响的个体更有可能出现年龄相关的低骨密度。LDF 扫描对因挛缩或伪影而导致腰椎和全身扫描通常无效的患者很有用。尽管下肢骨折的发生与运动或骨密度无关，但了解个体的骨骼健康状况可能会导致采取干预措施来改善骨骼健康。
