Katsuhiko Honma

Computed tomographic evaluation of bone formation after secondary bone grafting of alveolar clefts

PURPOSE The purpose of this article was to evaluate the initial volume of alveolar clefts and the bone bridges formed in patients who had undergone secondary bone grafting. PATIENTS AND METHODS Fifteen cleft patients were studied. Computed tomography (CT) scans were made at 2-mm slice sections immediately before operation and at 3 months and 1 year postoperatively. The volume of the alveolar clefts and bone bridges was calculated from stored images by using an image scanner and a personal computer. RESULTS The mean cleft volume of the patients was 1.1 +/- 0.3 cm3. The corresponding volume of the bone bridges 3 months and 1 year postoperatively were 1.2 +/- 0.6 cm3 and 1.1 +/- 0.5 cm3, respectively. The value at 1 year was significantly decreased compared with that at 3 months. CONCLUSIONS Adequate bone bridging was maintained for 1 year. However, it is suggested that the grafted site should be restored with a functioning tooth or a dental implant to place it under physiologic stress, because the volume of the bone bridges tends to decrease from 3 months to 1 year.

Masticatory function in patients with mandibular prognathism before and after orthognathic surgery.

Masticatory function was analyzed in 54 patients with mandibular prognathism before or after orthognathic treatment and in 40 adults with normal occlusion. Masticatory efficiency was evaluated spectrophotometrically by measuring the amount of adenosine triphosphate eluted from masticated adenosine triphosphate granules. Occlusal contact was evaluated by calculating the number and area of occlusal contacts from the illuminated images of a silicone record of the occlusion that was stored in the image analysis system with the aid of a charge-coupled device camera. The mean masticatory efficiency of the preoperative group was approximately half that of the control group. The value for the postoperative group was slightly higher than that for the preoperative group, but there was no statistical difference between the two groups. Likewise, the number and area of occlusal contacts in the preoperative group were also approximately half or less as compared with those of the control group, and they did not show significant changes postoperatively. Statistically, there were correlations between the masticatory efficiency and the number and area of occlusal contacts. The results indicate that although the occlusal relationship of the upper and lower teeth were greatly improved by orthognathic treatment, the postoperative occlusion is not tight enough and may need further adjustment at the end of the treatment.

Three-dimensional analysis of facial morphology before and after orthognathic surgery

A method for three-dimensional analysis of the facial hard- and soft-tissue morphologies is described. The soft-tissue analysis consisted of calculating three-dimensional values of reference points on the face by perspective transformation of their values in two pairs of photographs, taken simultaneously, from the right and left sides of the face. The shape of the mandible was analyzed three-dimensionally by the simultaneously taken frontal and lateral cephalograms. The hard- and soft-tissue changes were analyzed with the method in 28 patients in whom mandibular prognathism had been corrected by orthognathic surgery. The magnitude of the surgically-produced soft tissue volumetric changes in the anterior mandibular region was proportional to the posterior movement of the mandible. Asymmetry of the face also improved in response to correction of lateral deviation of the mandible and a close correlation between the directional indices of asymmetry of the hard and soft tissues was observed. Thus, the method was found to be quite useful for the analysis of facial morphology in jaw deformity.

The Efficacy of Recombinant Human Erythropoietins after Autologous Blood Collection in Patients Undergoing Two Jaw Surgery.

The efficacy of recombinant human erythropoietin (Epo and Esp) was studied inpatients who underwent two jaw surgery for correction of jaw deformities after collection of 1200ml of autologous blood.The patients were classified into group A (7 patients) with administration of Fe alone, group B (12 patients) with Fe and Epo (9 times), group C (5 patients) with Fe and Esp (3 times) and group D (6 patients) with Fe and Esp (4 times) depending on the results of blood examination. Mean Hb, RBC and Ht before surgery in group A were 12.1g/dl, 401×104/μl and 35.9%, respectively. The decreases of these values before sugery were maximum in group A and yet the values were higher than those of the other groups. Despite significantly lower Hb and Ht before blood collection, mean Hb, RBC and Ht before surgery for groups B, C and D were 10.5-11.4g/dl. 354-386×104/μl and 32.0-34.7%, respectively and they showed good recovery after surgery. Among these groups, group C showed the poorest results.In conclusion, recombinant human erythropoietin, in particular Esp with a total of 4 injections, was most effective in restoring anemia after blood collection.

Complications During Operation for Jaw Deformities.

Unfavorable fractures and blood vessel injuries encountered during 196 operations on 185 patients who underwent surgical correction of jaw deformities were studied to analyze the causes. There were 12 unfavorable fractures (6.1%) and 9 blood vessel injuries (4.6%). All complications occurred in two-jaw surgery and sagittal splitting ramus osteotomy (SSRO). Blood loss and operation time were significantly higher in cases with complications than in those without complication in SSRO.SSRO. With the exception of one case, all fractures were encountered during SSRO. Most of them were minor fractures occurring along the osteotomy line, but relatively large segments of the proximal segment were fractured in 3 cases, 2 of which were not repositioned. Blood vessel injury of the descending palatine artery was encountered in 2 cases of Le Fort I osteotomy. In SSRO, injuries of the inferior alveolar artery, facial artery, and unidentified artery occurred in 3, 1, and 3 cases, respectively. Ligation of the arteries was required to stop bleeding in 2 cases, whereas in the other cases, bleeding was controlled by packing of gauze or oxidized regenerated cellulose.Insufficient bony cut, forcible splitting, and careless handling of surgical instruments were the main causes of the complications. It is thought that the complications can be avoided by precise analysis of structures at the operation site by computed tomography, sufficient bony cut, and careful handling of surgical instruments.

Severe Facial Asymmetry Treated by Two Jaw Surgery and Hydroxylapatite Block Graft; Report of Two Cases

Two cases of severe facial asymmetry resulting from progressive facial hemiatrophy and hemifacial microsomia treated by two jaw surgery and hydroxylapatite (HA) block graft are reported. Both cases had a similar three-dimensional jaw deformity. Two jaw surgeries were performed to improve the occlusal plane inclination and the asymmetric contour of the mandible. HA blocks which were made from wax models on the mandible models reconstructed from CT, were grafted to improve the remaining deformity. Various problems associated with the procedures are discussed.