Bradley J P, Shahinian H, Levine J P, Rowe N, Longaker M T
Institute of Reconstructive Plastic Surgery, New York University Medical Center, NY 10016, USA.
Plast Reconstr Surg. 2000 Jun;105(7):2416-23. doi: 10.1097/00006534-200006000-00017.
Newborns with in utero cranial vault molding can present with severe forms of plagiocephaly. Intrauterine constraint has been proposed as one cause for craniosynostosis. The purpose of this experiment was to investigate whether rigid plate fixation across a fetal cranial suture, representing a severe form of growth restriction in utero, would lead to cranial suture fusion in a fetal lamb model. Six fetal lambs at 85 to 95 days gestation (term = 145 days) underwent laparotomy, hysterotomy, fetal coronal scalp incision, and miniplate screw fixation across the right coronal suture in utero. Two unoperated twins and four unoperated age-matched lambs were used as controls (n = 12). Animals were killed at both 4 and 8 weeks postoperatively. Fetal head analysis consisted of gross examination, photography, basilar and lateral radiographs, and three-dimensional computed tomographic scans. Cranial suture analysis consisted of imaging by computed tomographic scan (axial and sagittal cuts) and histology of experimentally plated coronal sutures, contralateral nonplated coronal sutures and twin control coronal sutures. Gross examination, radiographs, and three-dimensional computed tomographic analysis of heads with cranial suture plating showed ipsilateral forehead flattening, contralateral forehead bossing, superiorly displaced ipsilateral orbital rim, anterolateral projection of ipsilateral malar eminence, and anterior position of the ipsilateral ear point compared with the contralateral side of the same animal and normal controls. There was no change in nasal root, chin point, or predentition occlusal plane. Although analysis of the plated coronal sutures by computed tomographic scans showed diminished width or even stenosis, the histology revealed narrowed but patent experimental coronal sutures at 4 and 8 weeks. Contralateral, nonplated coronal sutures were not only patent, but widened compared with normal control sutures. This finding may have represented compensatory changes in the contralateral coronal suture caused by growth restriction at the plated suture. These data demonstrate that intrauterine growth restriction across a cranial suture caused by compression plate fixation resulted in deformational skull changes, not craniosynostosis. In addition, these data strongly support a role for in utero positional molding secondary to growth restriction in the maternal pelvis as a cause for nonsynostotic plagiocephaly seen in newborns.
子宫内存在颅穹窿塑形的新生儿可能会出现严重形式的斜头畸形。子宫内的限制因素被认为是颅缝早闭的一个原因。本实验的目的是研究在胎羊模型中，横跨胎儿颅骨缝线进行刚性钢板固定（代表子宫内严重的生长受限形式）是否会导致颅骨缝线融合。六只妊娠85至95天（足月为145天）的胎羊接受了剖腹术、子宫切开术、胎儿冠状头皮切口，并在子宫内横跨右冠状缝进行微型钢板螺钉固定。两只未手术的双胞胎和四只年龄匹配的未手术胎羊用作对照（n = 12）。动物在术后4周和8周时被处死。胎儿头部分析包括大体检查、摄影、基底和侧位X线片以及三维计算机断层扫描。颅骨缝线分析包括计算机断层扫描成像（轴向和矢状切面）以及对实验性植入钢板的冠状缝、对侧未植入钢板的冠状缝和双胞胎对照冠状缝进行组织学检查。对植入颅骨缝线钢板的头部进行大体检查、X线片和三维计算机断层扫描分析显示，与同一动物的对侧和正常对照相比，同侧额头扁平、对侧额头隆起、同侧眶缘上移、同侧颧骨突出部向前外侧突出以及同侧耳点靠前。鼻根、颏点或牙列前咬合平面无变化。尽管通过计算机断层扫描对植入钢板的冠状缝进行分析显示宽度减小甚至狭窄，但组织学检查显示在4周和8周时实验性冠状缝变窄但仍通畅。对侧未植入钢板的冠状缝不仅通畅，而且与正常对照缝线相比增宽。这一发现可能代表了植入钢板缝线处生长受限引起的对侧冠状缝的代偿性变化。这些数据表明，由加压钢板固定导致的横跨颅骨缝线的子宫内生长受限会导致颅骨变形，而非颅缝早闭。此外，这些数据有力地支持了子宫内由于母亲骨盆生长受限导致的位置塑形在新生儿非缝早闭性斜头畸形病因中的作用。
