The effect of sutural dura mater on suture formation: an experimental study on newborn rabbits

The difference between the dura mater underlying cranial sutures and dura materunderlying cranial bones was shown in previous experimental studies. Based on thisknowledge, we planned a study to investigate the suture formation capacity of duramater underlying cranial sutures on newborn rabbit model. We have created a criticalsized defect over the interfrontal sutures. We cauterized the dura mater underlyingthe cranial suture without disrupting its integrity afterward. And we observed thebone regeneration for newly formed cranial suture. We thought that whether a cranialsuture formed on newly regenerated bone or not, the result will be a step towards theunderstanding the pathogenesis of craniosynostosis.Premature fusion of skull bones (craniosynostosis) cause severe skull deformities,skullbase and brain defomities. Studies shown that dura mater, underlying suturelines, causes delayed suture fusion. Recent studies showed that dura materunderlying cranial sutures and dura mater underlying the flat portiones of cranialbones have different effects on calvarial growth. Dura mater underlying the flatportions of cranial bones shows an influence on osteogenesis, but sutural dura matershows an influence on chondrogenesis additon to osteogenesis.In this study, in rabbit model, a 10mm cranial bone defect was created on sagittalsuture line, and dura mater was cauterized without compromising the integrity andbone regeneration and suture formation was observed in experimental group (n:10).In control group (n:10), after creation of 10mm defect on sagittal suture line withdura mater keeped unharmed, regeneration and suture formation was observed. Aftera follow up period of 8 weeks, 3D computerized tomography images were taken andcalvarial defect areas were surgically removed for histologic analysis of boneregeneration and suture formation after sacrification of the subjects with over dozedanesthetics.As the results of this study group 1 (with dura cauterization) showed anaverage 59.2% (47.9-71,5%) bone regeneration. Average bone regeneration wasmeasured as 62.6% (50.2?72.6%). The initial and 8th week defect sizes werecompared and the reduction rates of calvarial defet size were statistically significantfor both groups (p<0,001). The comparison of the defect size between group1 and 2 ,vwas not statistically significant (p:0.538). The comparison of the defect area betweengroup1 and 2, was not statistically significant (p:0.638). The comparison of thedefect area between group1 and 2, was not statistically significant (p:0.640)In histological assessements of group 1 (with dura cauterization) (n:5) 4 subjects(80%) showed bone fusion wtih callus formation between regenerated bone endswhere the interfrontal suture formation expected. In group 2 (n:7) all subjects showedsuture formation between regenerated bone ends where the interfrontal sutureformation expected. Results were statistically significant for for both groups(p<0.0001)As a result, the effect of sutural dura mater on cranial suture formation has beendemonstrated in this study.