Patel Vikas V, Wuthrich Zachary R, Ortega Alicia, Ferguson Virginia L, Lindley Emily M
Department of Orthopedics, Divisions of Spine Surgery and Research, University of Colorado Anschutz Medical Campus, Aurora, Colorado.
Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado.
Int J Spine Surg. 2020 Oct;14(5):694-705. doi: 10.14444/7101. Epub 2020 Oct 19.
The effects of vitamin D deficiency on spinal fusion are not well studied, nor are approaches to overcoming deficiency-related detrimental effects. The purpose of this study was to (1) evaluate the effects of vitamin D deficiency on spine fusion in a rat model, and (2) determine whether recombinant human bone morphogenetic protein-2 (rhBMP-2) can improve outcomes in deficient rats.
Sprague-Dawley rats were assigned to a vitamin D group: vitamin D sufficient (14), vitamin D deficient (16), vitamin D postoperative rescue (15). Posterolateral fusion was performed at L3-4 and L5-6, with one level receiving rhBMP-2 and the other allograft. Following 6 weeks, the spines were harvested for micro-computed tomography (micro-CT) and histological analyses. Fusion was assessed via manual palpation and micro-CT assessment. Micro-CT images were analyzed for bone microarchitecture in intact L5 vertebral bodies and within fused bone masses treated with rhBMP-2.
There were no significant effects of vitamin D status on fusion assessments. However, the microarchitecture of native bone in the intact L5 vertebral bodies of vitamin D-sufficient rats showed significantly greater trabecular thickness ( < .001) and bone volume fraction ( < .001), with decreased trabecular spacing ( < .001), than that of vitamin D-deficient rats. Fusion masses of rhBMP-2 levels also showed significant effects of vitamin D supplementation on both bone volume fraction and trabecular thickness. Histological analysis confirmed that robust bone formation was observed in rhBMP-2-treated fusions, but not in fusion levels treated with allograft.
Overall, vitamin D deficiency decreased trabecular bone microarchitecture, and treatment with rhBMP-2 improved outcomes across all vitamin D groups.
Given the prevalence of vitamin D deficiency in spine surgery patients, vitamin D supplementation may be a cost-effective method for reducing the risk of pseudoarthrosis.
维生素D缺乏对脊柱融合的影响尚未得到充分研究，克服与缺乏相关的有害影响的方法也未得到充分研究。本研究的目的是：（1）在大鼠模型中评估维生素D缺乏对脊柱融合的影响；（2）确定重组人骨形态发生蛋白-2（rhBMP-2）是否能改善维生素D缺乏大鼠的结局。
将Sprague-Dawley大鼠分为维生素D组：维生素D充足组（14只）、维生素D缺乏组（16只）、维生素D术后补充组（15只）。在L3-4和L5-6节段进行后外侧融合，一个节段接受rhBMP-2治疗，另一个节段接受同种异体骨移植。6周后，取出脊柱进行微型计算机断层扫描（micro-CT）和组织学分析。通过手动触诊和micro-CT评估来评估融合情况。对完整L5椎体和用rhBMP-2治疗的融合骨块内的骨微结构进行micro-CT图像分析。
维生素D状态对融合评估没有显著影响。然而，与维生素D缺乏的大鼠相比，维生素D充足的大鼠完整L5椎体的天然骨微结构显示，其小梁厚度（P<0.001）和骨体积分数（P<0.001）显著更大，小梁间距减小（P<0.001）。rhBMP-2治疗节段的融合块也显示，补充维生素D对骨体积分数和小梁厚度均有显著影响。组织学分析证实，在rhBMP-2治疗的融合中观察到了强劲的骨形成，但在同种异体骨移植治疗的融合节段中未观察到。
总体而言，维生素D缺乏会降低小梁骨微结构，而rhBMP-2治疗可改善所有维生素D组的结局。
鉴于脊柱手术患者中维生素D缺乏的普遍性，补充维生素D可能是降低假关节风险的一种经济有效的方法。
