Stuehmer Constantin, Rücker Martin, Schumann Paul, Bormann Kai-Hendrik, Harder Yves, Sinikovic Branko, Gellrich Nils-Claudius
Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany.
J Craniomaxillofac Surg. 2009 Jul;37(5):258-62. doi: 10.1016/j.jcms.2009.01.005. Epub 2009 Mar 18.
In plastic and reconstructive surgery, self-activating hydrogel expanders are used to augment soft-tissue space. The purpose of this study was to investigate the morphological response of underlying bone to the constant pressure exerted by a hydrogel expander.
Eighteen Lewis rats were randomly divided into three groups. In group 1, a hydrogel expander was placed subperiosteally directly onto the calvaria of the rats. In group 2, the expander and the underlying bone were separated by a polydioxanone (PDS) foil. Group 3 animals served as controls. Before and 14 days after the insertion of the expanders, micro-computed tomography (CT) images were obtained and fused. We analysed hydroxyapatite density beneath and at the periphery of the expander and performed a histomorphometric bone analysis.
Whereas there were no significant differences (p<0.05) (groups 1 and 2) in bone density at the periphery of the expanders between the study groups, a significant decrease in hydroxyapatite density beneath the expanders was observed in those animals in which the devices were placed directly onto the calvaria (group 1). Whereas bone thickness was unaffected at the periphery of the expanders in all groups, it was significantly decreased beneath the expanders in all implanted animals. A morphological examination revealed resorption lacunae with a diameter of 218.4+/-56 mICROm in those rats in which the expanders had been placed directly onto the calvaria.
This study shows the direct influence of hydrogel expanders on underlying bone. Whereas bone resorption and connective tissue formation also occur underneath hydrogel expanders, these effects can be avoided if the expander and the underlying bone are separated by PDS foil. The key to success is to ensure the appropriate placement of expanders and thus to avoid bone resorption.
在整形和重建手术中，自激活水凝胶扩张器用于增加软组织空间。本研究的目的是调查水凝胶扩张器施加的恒定压力对其下方骨骼的形态学反应。
将18只Lewis大鼠随机分为三组。在第1组中，将水凝胶扩张器骨膜下直接放置在大鼠的颅骨上。在第2组中，扩张器与下方的骨骼之间用聚二氧六环酮（PDS）箔隔开。第3组动物作为对照。在插入扩张器之前和之后14天，获取并融合微型计算机断层扫描（CT）图像。我们分析了扩张器下方和周边的羟基磷灰石密度，并进行了组织形态计量学骨分析。
尽管研究组之间扩张器周边的骨密度没有显著差异（p<0.05）（第1组和第2组），但在将装置直接放置在颅骨上的动物（第1组）中，观察到扩张器下方的羟基磷灰石密度显著降低。尽管所有组中扩张器周边的骨厚度未受影响，但在所有植入动物中，扩张器下方的骨厚度显著降低。形态学检查显示，在将扩张器直接放置在颅骨上的大鼠中，存在直径为218.4±56μm的吸收陷窝。
本研究显示了水凝胶扩张器对其下方骨骼的直接影响。尽管在水凝胶扩张器下方也会发生骨吸收和结缔组织形成，但如果扩张器与下方的骨骼用PDS箔隔开，这些影响是可以避免的。成功的关键是确保扩张器的正确放置，从而避免骨吸收。
