Liu Xuecheng, Lyon Roger, Meier Heidi T, Thometz John, Haworth Steven T
Musculoskeletal Functional Assessment Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53201, USA.
Photomed Laser Surg. 2007 Dec;25(6):487-94. doi: 10.1089/pho.2006.2075.
The purpose of the study was to demonstrate the biological effects of low-level laser therapy (LLLT) on tibial fractures using radiographic, histological, and bone density examinations.
Fourteen New Zealand white rabbits with surgically induced mid-tibial osteotomies were included in the study. Seven were assigned to a group receiving LLLT (LLLT-A) and the remaining seven served as a sham-treated control group (LLLT-C). A low-energy laser apparatus with a wavelength of 830 nm, and a sham laser (a similar design without laser diodes) were used for the study. Continuous outflow irradiation with a total energy density of 40 J/cm(2) and a power level of 200 mW/cm(2) was directly delivered to the skin for 50 seconds at four points along the tibial fracture site. Treatment commenced immediately postsurgery and continued once daily for 4 weeks.
Radiographic findings revealed no statistically significant fracture callus thickness difference between the LLLT-A and LLLT-C groups (p > 0.05). However, the fractures in the LLLT-A group showed less callus thickness than those in LLLT-C group 3 weeks after treatment. The average tibial volume was 14.5 mL in the LLLT-A group, and 11.25 mL in the LLLT-C group. The average contralateral normal tibial volume was 7.1 mL. Microscopic changes at 4 weeks revealed an average grade of 5.5 and 5.0 for the LLLT-A group and the LLLT-C group, respectively. The bone mineral density (BMD) as ascertained using a grey scale (graded from 0 to 256) showed darker coloration in the LLLT-A group (138) than in the LLLT-C group (125).
The study suggests that LLLT may accelerate the process of fracture repair or cause increases in callus volume and BMD, especially in the early stages of absorbing the hematoma and bone remodeling. Further study is necessary to quantify these findings.
本研究旨在通过影像学、组织学和骨密度检查来证明低强度激光疗法（LLLT）对胫骨骨折的生物学效应。
本研究纳入了14只通过手术造成胫骨中段截骨的新西兰白兔。7只被分配到接受LLLT的组（LLLT-A），其余7只作为假治疗对照组（LLLT-C）。使用波长为830 nm的低能量激光设备和假激光（一种没有激光二极管的类似设计）进行研究。在胫骨骨折部位沿四个点直接向皮肤进行连续流出照射，总能量密度为40 J/cm(2)，功率水平为200 mW/cm(2)，持续50秒。治疗在手术后立即开始，每天进行一次，持续4周。
影像学检查结果显示，LLLT-A组和LLLT-C组之间的骨折骨痂厚度差异无统计学意义（p>0.05）。然而，治疗3周后，LLLT-A组的骨折骨痂厚度比LLLT-C组的薄。LLLT-A组的平均胫骨体积为14.5 mL，LLLT-C组为11.25 mL。对侧正常胫骨的平均体积为7.1 mL。4周时的微观变化显示，LLLT-A组和LLLT-C组的平均等级分别为5.5和5.0。使用灰度（从0到256分级）确定的骨矿物质密度（BMD）显示，LLLT-A组（138）比LLLT-C组（125）颜色更深。
该研究表明，LLLT可能会加速骨折修复过程或导致骨痂体积和BMD增加，尤其是在血肿吸收和骨重塑的早期阶段。需要进一步研究来量化这些发现。
