Craniofacial growth following rigid fixation: suture excision, miniplating, and microplating

The effects of plating the coronal and nasofrontal sutures on skull growth were studied in New Zealand white rabbits. Removal of the underlying coronal suture and reduction in the size of the plate were also studied with regard to their effect on growth. Three-dimensional coordinate landmarks located on the skulls were digitized and analyzed to determine the differences in form between operated and unoperated animals using Euclidian distance matrix analysis. Interlandmark distances in three dimensions were compared to demonstrate changes induced by plating. Coronal suture plating (n = 8) resulted in local decreases in dimensions of the plated bones and contralateral and adjacent skull size increases. Removal of the coronal suture without plating (n = 6) resulted in an increase in the size of the adjacent frontal bone and an increase in the width of the suture. Placement of a plate after removal of the underlying suture (n = 8) resulted in decreases in dimensions of the plated bones, with distant length and width increases in a pattern similar to that of the skulls that were simply plated. Plating across the nasofrontal suture (n = 6) resulted in decreases in dimensions in the plated bone, with some distant width increases at the midfrontal bone, the coronal suture, and the posterior parietal bone. In this group, no contralateral increase in dimensions was detected. This is unlike the pattern observed for the animals with a coronal suture plate only. Placing a microplate across the coronal suture (n = 6) resulted in morphologies similar to those with the use of miniplates across the coronal suture. We propose that the varying morphologies in these groups represent compensatory changes accompanying growth restriction induced by plating. We suggest that the lack of contralateral growth increases with nasofrontal suture plating results from lesser effects on the underlying growing cranial contents at this location, as compared with the coronal suture. We find consistent results despite suture removal, change in plate location, and change in plate size.