Clinical research of angle-splitting ostectomy based on three dimensional computed tomography true-up technique / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To illustrate the morphological changes of mandible after angle-splitting ostectomy.</p><p><b>METHODS</b>From January 2006 to April 2008, 10 cases had undergone mandibular angle-splitting ostectomy to reduce the width of the lower face. For each patient, CT datum of mandible at three stages (preoperative, immediate postoperative, 6 months postoperative) were collected. By the application software of reverse engineering (Surfacer V9) and true-up and dissection techniques based on three-dimensional spiral computed tomography (3D-CT), operative efficacy and bone regeneration at the operation area of angle-splitting ostectomy were evaluated 6 months postoperative.</p><p><b>RESULTS</b>1) Concavity could be seen at the angle-splitting ostectomy area 6 months postoperative, especially at the mandibular external oblique line region. Average cup depth was (3.64 +/- 1.67) mm by contrasted to preoperative. Diminution of bone volume was 55% +/- 9% for the local operative area 6 months postoperative. 2) Bone regeneration could be seen at the area that mandibular outer cortex had been removed. Compared with immediate postoperative, ratio of neoformative bone was 84.6% +/- 7.3% 6 months postoperative. The main region of bone regeneration was mandibular angle.</p><p><b>CONCLUSION</b>Mandibular angle-splitting ostectomy is an effective technique for reducing the width of the lower face. Masseter muscular movement should be restricted postoperative to prevent hyperostosis at the angle area.</p>

Comparative study of onlay bone graft absorption of outer cortex from mandible and cranium / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the value of application of mandibular outer cortex as bone graft by comparing its bone absorption with cranial outer cortex.</p><p><b>METHODS</b>8 minitype grown-up pigs at the age of 8 - 12 months underwent surgery of taking out the same size (2.5 cm x 1.0 cm) of outer cortex from mandible and craninium. The volume of the outer cortex was measured by volume-displacement method. Then the outer cortex of mandible and cranium were onlay grafted to the each side of the pig snout, respectively. 12 weeks later, 2 pigs were randomly selected for histological examination. The other 6 pigs were killed 24 weeks after surgery for measurement of the bone graft volume and histologic examination.</p><p><b>RESULTS</b>The bone graft absorption rate was (41 +/- 5)% for mandibular outer cortex and (46 +/- 12)% for cranial outer cortex, showing no significant difference between them (P = 0.51). The histologic examination results also had no marked difference in the bony healing and reforming between the two graft.</p><p><b>CONCLUSIONS</b>Mandibular outer cortex is a good donor site for onlay bone graft in craniofacial region.</p>