Ito M, Fay L A, Ito Y, Yuan M R, Edwards W T, Yuan H A
Department of Orthopaedics, Hokkaido University School of Medicine, Sapporo, Japan.
Spine (Phila Pa 1976). 1997 Feb 15;22(4):382-8. doi: 10.1097/00007632-199702150-00005.
This study was designed to examine stress-shielding effects on the spine caused by rigid implants and to investigate the effects of pulsed electromagnetic fields on the instrumented spine.
To investigate the effects of pulsed electromagnetic fields on posterolateral spinal fusion, and to determine if osteopenia induced by rigid instrumentation can be diminished by pulsed electromagnetic fields.
Although device-related osteopenia on vertebral bodies is of a great clinical importance, no method for preventing bone mineral loss in vertebrae by stiff spinal implants has been effective.
Twenty-eight adult beagles underwent L5-L6 destabilization followed by posterolateral spinal fusion. The study was divided into four groups: 1) Group CNTL: without instrumentation, without pulsed electromagnetic fields, 2) Group PEMF: without Steffee, with pulsed electromagnetic fields, 3) Group INST: with Steffee, without pulsed electromagnetic fields, 4) Group PEMF + INST: with Steffee, with pulsed electromagnetic fields. At the end of 24 weeks, the dogs were killed, and L4-L7 segments were tested biomechanically without instrumentation. Radiographs and quantitative computed tomography assessed the condition of the fusion mass.
Stress shielding was induced in the anterior vertebral bodies of L6 with the Steffee plates; bone mineral density was increased with the addition of pulsed electromagnetic fields, regardless of the presence or absence of fixation. A decrease in flexion and bending stiffness was observed in the Group INST; pulsed electromagnetic fields did increase the flexion stiffness regardless of the presence or absence of fixation, although this was not statistically significant.
Use of pulsed electromagnetic fields has the potential to minimize device-related vertebral-bone mineral loss.
本研究旨在检测刚性植入物对脊柱的应力遮挡效应，并探究脉冲电磁场对植入器械的脊柱的影响。
研究脉冲电磁场对脊柱后外侧融合的影响，并确定刚性器械引起的骨质减少是否可通过脉冲电磁场减轻。
尽管椎体上与器械相关的骨质减少具有重要临床意义，但尚无通过坚硬的脊柱植入物预防椎体骨矿物质流失的有效方法。
28只成年比格犬接受L5-L6失稳手术，随后进行脊柱后外侧融合。研究分为四组：1）对照组：无器械植入，无脉冲电磁场；2）脉冲电磁场组：无Steffee钢板，有脉冲电磁场；3）器械植入组：有Steffee钢板，无脉冲电磁场；4）脉冲电磁场+器械植入组：有Steffee钢板，有脉冲电磁场。24周结束时，处死犬只，对L4-L7节段在未植入器械的情况下进行生物力学测试。通过X线片和定量计算机断层扫描评估融合块情况。
Steffee钢板导致L6椎体前部出现应力遮挡；无论有无内固定，添加脉冲电磁场均可增加骨矿物质密度。器械植入组观察到屈伸和弯曲刚度降低；无论有无内固定，脉冲电磁场均增加了屈伸刚度，尽管这在统计学上无显著意义。
使用脉冲电磁场有可能将与器械相关的椎体骨矿物质流失降至最低限度。
