Effect of Chitosan, betaig-h3 and Human Bone Morphogenic Protein-4 on Early Bony Consolidation in Distraction Osteogenesis of the Canine Mandible

Sixteen dogs were used to study the effect of bone morphogenic protein(BMP-4), betaig-h3 and chitosan during the early bony consolidation stage in the distracted zones of mandibles. The lateral surface of the mandibular body was exposed in the subperiosteal plane and vertical osteotomy was carried out on the mandibular body. An external distraction device was applied to the mandibular body about 1 cm apart from the osteotomy line. Mandibular distraction was started 5 days after the mandibular osteotomy at a rate of 2 mm per day for a total of 10 mm distraction for 5 days. The experimental group was divided into 4 groups: control group, BMP-4 group, betaig-h3 group and chitosan group depending on the injected material into the distracted area. Four dogs were allocated to each group. On the day of completion of distraction, 0.5 ml of BMP-4, 0.5 ml of betaig-h3, 0.5 ml of 5% chitosan solution was injected respectively into the distracted area of each group with the same amount of tripolyphosphate in dual syringe for solidification of the injected solution. In the control group, 1 ml of tripolyphosphate was injected into the distracted area. After injection of the study materials, the distraction device was left in place for 4 or 7 weeks to allow bony consolidation. Radiographs were taken weekly. Two dogs in each group, a total of eight dogs, were sacrified in 4 weeks, and another eight dogs in 7 weeks after completion of distraction. Bone specimens of the distracted mandibles were taken for histologic examination. The mineral density of the distracted bone was measured during the radiological procedures and analysed by the computer. In the radiographs of the distracted areas of the mandibles, the control group has shown a mostly radiolucent zone but the other groups have shown the radiodense zones with various width of central radiolucent zones. The central radiolucent zone became narrower in time and vertical thickness of the radiodense zone was about twice thicker in 7 weeks than that of 4 weeks after finishing bone distraction. BMP-4 group showed the thickest radiodense zone and the chitosan group shows the thinnest radiodense zone. The mineral density of bone was highest in the BMP-4 group and lowest in the control group. In the histological findings of the distracted areas of mandibles, the control group showed whole fibrous tissue but the other groups showed new woven bones with central narrow fibrous interzone. The degree of new bone formation was most remarkable in the BMP-4 group and was least remarkable in the chitosan group. In conclusion, there was an active formation of a new bone in the distracted area of the mandible by injection of BMP-4, betaig-h3 and chitosan. The new bone formation was most remarkable in the BMP-4 group followed by betaig-h3, chitosan and control group. These findings suggest that BMP-4 is clinically worth using for early bony consolidation in the distraction osteogenesis.

Tissue Engineered Cartilage Formation using Human Hyaline Chondrocytes and Elastic Chondrocytes

The purpose of this study was to evaluate the influence of different types of PLGA scaffolds on the formation of human auricular and septal cartilages. The scaffolds were formed in tubular shape from 110,000 g/mol PLGA (poly lactic glycolic acid) and 220,000 g/mol one. Elastic cartilage was taken from the ear of a patient aged under 20 years old and hyaline cartilage from the nasal septum. The chondrocytes cells were then isolated by Klausburn method. After second passages, the chondrocytes were seeded on the PLGA scaffolds followed by in vitro culture for one week. The cells-PLGA scaffold complex was implanted at the back of nude mouses for 8 weeks. The tissue engineered cartilages were separated from nude mouse and examined histologically after staining with the Hematoxylin Eosin and Verhoeff. The formation of extracellular matrix and the porosity of the scaffolds were examined by scanning electron microscopy. The pores were well formed and uniformly distributed in both 110,000 g/mol and 220,000 g/mol PLGA scaffolds. The extracellular matrix was formed better in 110,000 g/mol PLGA compared to 220,000 g/mol one. And hyaline cartilage was proliferated better in vitro culture than elastic cartilage. After 8 weeks in vivo culture, cartilage was well formed with 110,000 g/mol PLGA, however lumen was collapsed. In contrast with 220,000 g/mol PLGA scaffold, neocartilage was formed in minimal amount while the architecture of scaffold was well preserved. Elastic cartilage seems to be better than hyaline one in terms of neocartilage formation. From the analysis after Verhoeff staining the cartilages, the neocartilage from elastic cartilage was proved to be elastic cartilage. In summary, there was no significant difference between elastic cartilage and hyaline cartilage in their morphologies, proliferation rates and the degree of cartilage formation since they were tissue engineered, however marked difference was found in neocartilage formation and preservation of scaffold architecture between 110,000 g/mol PLGA scaffold and 220,000 one. From the present findings, it is concluded that the influence of scaffold materials is significantly higher than that of different types of cells on the formation of new tissues.

Periareolar Reduction Mammoplasty

The goals of the reduction mammoplasty are to reduce the volume of the breast, to create aesthetic shape that is stable over time, to maintain blood supply and innervation to the nipple-areolar complex, and to make fine limited scars. There are 3 rationales in our reduction mammoplasty. To reduce the scar, we perform the periareolar incision. To make effective reduction of the breast volume, and to preserve blood supply and innervation to the nipple-areolar complex, we use a central or an inferior pedicle technique. To prevent areolar widening, we use a purse-string suture. We performed the periareolar reduction mammoplasty to 36 breasts in 18 patients from Jul. 1998 to Jun. 2000. The mean follow up period was 8 months. The mean age was 41 and mean resection amount was 420 gm per breast. Most patients satisfied with their fine periareolar scars, adequate size of breasts and the innervation of the nipple-areolar complex. We applied this procedure to all kinds of macrostomia. The greatest advantage of the periareolar reduction mammoplasty is the inconspicuous limited scar. Other advantages over conventional technique include preservation of sensitivity to the nipple-areolar complex and shorter operative time. As disadvantages, 10 breasts(28%) showed areolar widening. In 8 of 10 breasts with areolar widening, purse-string suture was not applied in the skin flap margin of the outer circle and reoperation was executed to reduce the areolar size by excision of the widened areola. The application of the purse-string suture was carried out in 6 breasts. Two breasts with purse-string suture showed areolar widening possibly due to loosening of the purse-string suture knot. There were persistent periareolar wrinkles in 4 breasts and poor sensitivity to the nipple-areolar complex in 6 breasts in which more than 500 gm of breast tissue per breast was resected. Periareolar reduction mammoplasty is optimal for patients who require reduction of lesser than 500 grams per breast. In the severe macromastia with or without ptosis, inverted T-incision is preferable to the periareolar incision, and periareolar incision can be modified by adding wedge resection of the outer excess skin flap inferiorly which results in a periareolar and vertical scar below the nipple-areolar complex.

The Effect of an Artificial Dermis on Chondrogenesis from Perichondrium

The purpose of this study is to investigate the effect of artificial dermis(Terudermis(R)) on cartilage induction from perichondrium. A total of 24 rabbits were used and divided into control(n = 12) and experimental groups(n = 12). Each group was divided into 2 weeks(n = 6) and 4 weeks subgroups(n = 6). The dorsal skin of the rabbit ear was incised in reverse L-shape and the perichondrium was exposed. The silicone membrane from the Terudermis(R) , 1 x 1 cm sized,was removed. The Terudermis(R) was grafted on the exposed perichondrium in the experimental group. However, Terudermis(R) was not grafted in the control group. At 2 and 4 weeks after the surgery, the specimen was obtained and studied by histologic study. The results are as follows: 1. In control group at 2 weeks after surgery, the appearance of perichondrocytes and chondrocytes were not different from those of normal tissue. 2. In control group at 4 weeks after surgery, the extent of chondroblast differentiation and cartilage regeneration was insignificant compared to experimental group. 3. In experimental group at 2 weeks after surgery, we examined the active differentiation process of chondroblast beneath the perichondrium. The mean thickness of the neocartilage layer was 0.11+/-0.04 mm. 4. In experimental group at 4 weeks after surgery, there was an active regenerated new cartilage layer eneath the perichondrium, but the neocartilage layer was immature. The mean thickness of neocartilage layer was 0.33+/-0.10 mm. In conclusion, this study suggested that the grafted Terudermis(R) has an effect on chondrogenetic induction by activating the perichondrium.

Effect of Calcium Sulfate on Early Bony Consolidation in Distraction Osteogenesis

The purpose of this project was to study the effect of calcium sulfate on early bony consolidation in distraction osteogenesis in the dog model. Eight canine dogs were used for this study. The lateral surface of the mandibular body was exposed in the subperiosteal plane and the vertical osteotomy on the mandibular body was carried out. An external distraction device was applied to the mandibular body. Mandibular distraction was started 5 days after the osteotomy at a rate of 1mm per day for a total of 10mm distraction in the control group 1 and in the calcium sulfate group 1, and at a rate 2mm per day for a total of 10mm distraction in the control group 2 and in the calcium sulfate group 2. After completion of distraction, the gel type calcium sulfate was implanted into the distracted zone in the calcium sulfate groups. External distraction device was left in place for 6 weeks to allow for bony consolidation. Serial radiographs were carried out every week. One dog of each group, a total of four dogs, were sacrificed at the time of 3 weeks and another four dogs at 6 weeks after distraction. Address Correspondence : Byung Chae Cho, M.D., Department of Plastic and Reconstructive Surgery, College of Medicine, Kyungpook National University, 50, Samduk-Dong 2Ga, Chung-Gu, Taegu 700-421, Korea, Tel: 053) 420-5681/Fax: 053)425-3879/E-mail: bccho@knu.ac.kr New bone was generated in the distracted zone in the control group 1 and in the calcium sulfate groups. However, new bone was not developed in the control group 2. In the calcium sulfate group 1, osteogenesis was seen and abundant active osteoblasts formed woven bone in the edges and center of the distracted zone by 3 weeks after calcium sulfate implantation. By 6 weeks after calcium sulfate implantation, much active woven bone had been formed in most of the area of the distracted zone with a narrow fibrous interzone. In the calcium sulfate group 2, new bone formation was developed in one half of the distracted zone at 6 weeks after implantation. New bone formation was lesser than the calcim sulfate group 2 at 6 weeks after implantation. In conclusion, calcium sulfate is effective for easily bony consolidation in distraction osteogenesis.

Osteodistraction of Midface Using Rigid External Distraction Device

We treated a total of 4 patients with midfacial hypoplasia, aged 12 to 19 years, using distraction osteogenesis between January 1998 and June 1999. In 3 patients with severe maxillary hypoplasia, we used rigid external distraction device developed by Dr. Polley. The distraction was performed from 5 days after Le Fort I osteotomy at a rate of 1 mm/day for 10 to 15 days. After distraction was completed, the device was left in place for another 6 weeks for bony consolidation. And then, an orthodontic face mask was used with elastic traction for 2 months. In one patient with partial hypoplasia of the midface, the osteotomized zygoma and a part of the maxilla was distracted selectively using rigid external distraction device a total of 15 mm. In the degree of SNA, mean value improved from 75.0(75.5, 75.0, 74.5) to 81.8(81.5, 83.0, 81.0) after 6 months later. In relapse rate, distracted length decreased from 10 mm to 6 mm, 15 mm to 8 mm, 13mm to 7 mm at 6 months later resulting in relapse rate of 44.3%. The follow-up period was from 7 to 26 months. Advantages of rigid external distraction device are highly effective technique of maxillary distraction, easy control of vector of distraction and no additional surgical procedure for removal of the device. In conclusion, the external distraction device is very useful for midface distraction.

Bimaxillary Osteodistraction in Adult Facial Asymmetry

We treated 9 patients with hemifacial microsomia or facial asymmetry between April 1998 and November 1999. The age of patients ranged from 21 to 45 years(mean 24.6). Six were women, 3 were men. The follow up period was 6 to 24 months(mean 15.3 months). The operative procedure was based on the Ortiz Monasterio's simultaneous mandibuiar and maxillary distraction technique. Ortiz Monasterio only freed the pterygomaxillay junction of the affected side, leaving the nasal septum and pterygomaxillary junction of the unaffected side intact. They also used external corticotomy on mandible. We modified the original Ortiz Monasterio's method by using complete Le Fort I osteotomy with complete separation of both pterygomaxillary junction and mandibular osteotomy to avoid the resistance during the distraction. In one patient of scleroderma with severe atrophy of the mandible and soft tissue on the right face, a free scapular osteocutaneous flap was done. One month later, simultaneous distraction of the maxilla, the transferred scapula bone and the mandible was performed. Among the 9 patients, bidirectional distraction was done in one patient, and intraoral device was applied in 3 patients. After 5 days of latent period, distraction was performed at a rate of 1 mm per day. After 6 to 8 weeks of consolidation period, intermaxillary fixation and distraction device were removed. Preoperatively, the deviation of occlusal plane ranged from 8 to 13 (mean 10.5 ). The length of distraction ranged from 7 mm to 20 mm(mean 13 mm). In 2 patients, there were radiologic evidences of relapse 6 months after distraction, but no significant change of facial appearance was found. Seven patients have maintained stable preoperative occlusion of of teeth as previous conditions and preoperative lateral open bite was improved postoperatively in 2 patients. Postoperative occlusal plane ranged from 0 to 1.

Anthropometric Study of the Upper Lip and Nose in Infants Younger than One Year Old

The face is a variable part of the body and characterized not only by each part but also by the interrelation of the parts. Because facial image is very complex, it is very difficult to standardize the facial profile. However, it is necessary to establish the facial anthropometry in the infant. We perforrned an anthropometric study of the linear length of soft tissue in 13 places of the nasolabial area using a spreading caliper and ruler for the purpose of establishing normal interrelationship of regional profile in newborns and 2, 4, 6 month old babies. Each age group was composed of 40 normal babies. Followings are our results in the order of newborn, 2, 4, 6 months old. Widths of columella were 3.2 mm, 3.5 mm, 3.7 mm, 3.8 mm, respectively. Heights of columella were 4.7 mm, 4.9 mm, 5.2 mm, 5.3 mm. Distances between medial alar bases were 13.7 mm, 14.4 mm, 17.4 mm, 17.6 mm. Lengths from alar to tip of Cupid's bow were 9.5 mm, 10.0 mm, 10.5 mm, 10.6 mm. Lengths from columella base to tip of Cupid's bow were 8.4 mm, 9.9 mm, 10.2 mm, 10.5 mm. Lengths from columella base to center of Cupid's bow were 8.3 mm, 9.5 mm, 9.8 mm, 9.9 mm. Lengths of one limb of Cupid's bow were 2.7 mm, 3.1 mm, 3.4 mm, 3.5 mm. Lengths from tip of Cupid's bow to commissure were 13.4 mm, 14.7 mm, 16.4 mm, 16.9 mm. Intercommissural distances were 26.8 mm, 30.3 mm, 30.8 mm, 32.5 mm. Widths of philtral column at columella base were 3.1 mm, 3.6 mm, 3.7 mm, 4.0 mm. Distances between philtral columns(mid portion) were 3.7 mm, 4.6 mm, 4.6 mm, 4.6 mm. Heights of nasal tip protrusion were 8.7 mm, 11.0 mm, 11.7 mm, 12.1mm. Widths of nose were 20.7 mm, 23.7 mm, 25.3 mm, 25.9 mm. As the treatment of cleft lip should be performed within 6 months of age, the exact data for the face are very important, especially in the nasolabial area. We expect our data to be useful as a guideline for the management of cleft lip patient under one year old.

Comparative Study of Subcutaneous Buried Suture Materials in Rabbits

To have useful information and basic rationale for selection of suture materials in the subcutaneous buried suture, a study on tensile strength, clinical handing property, scar nature and histological changes was done in rabbits with four kinds of absorbable suture materials (chromic catgut, Monocryl, coated Vicryl and PDS) and two kinds of nonabsorbable suture materials (Nylon and Gore-tex). The clinical handling property included pliability, ease of tying, knot security and passage in tissue. The tensile strength of the absorbable and non-absorbable suture materials was compared before and after subcutaneous implantation, and the histology of suture materials was examined after separate subcutaneous buried sutures. The test of tensile strength and the histological examination of suture materials were done on the 1st, 3rd, 7th, 14th, 30th and 90th day after subcutaneous implantation and suturing. In the clinical handing property, pliability was good in Vicryl. Ease of tying and knot security were good in both catgut and Vicryl, but passage in tissue was poor in both. In Gore-tex, pliability, ease of tying, knot security and tissue passage were better than Nylon. In the tensile strength of absorbable suture materials before implantation in the abdominal flap, Monocryl was the strongest one and catgut was the weakest one. Vicryl was a little stronger than PDS. The tensile strength of Moncryl rapidly dropped down from the 3rd day after implantation and became the weakest one after the 7th day of implantation. There was no remarkable change in the strength order of other absorbable suture materials. In the non-absorbable suture materials, Gore-tex was about two times stronger than Nylon before and after implantation. In histology, there were more severe and prolonged inflammatory reactions in absorbable suture materials than in nonabsorbables. The most severe reaction was seen in catgut. Monocryl, Vicryl and PDS were similar in inflammatory reaction. Severe giant cell and histiocytic reaction were seen in Vicryl. The least absorption was seen in PDS and it was well correlated with loss of tensile strength. Nylon showed less inflammatory reaction than Gore-tex. There are few clinical studies for recently developed Monocryl and Gore-tex. Our results suggest to us that Monmcryl is one of the best absorbable suture materials and Gore-tex is two times stronger than Nylon.

An Experimental Study on the Survival of Membranous Inlay Bone Graft on the Mandible

Bone graft is an important procedure in craniomaxillofacial reconstruction and the success of reconstruction depends on the survival of the grafted bone. In this study, the survival of the membranous inlay bone graft on the mandibles of dogs was investigated with bone scan and histologic examination. The inlay bone graft, 1x2cm critical-sized bone, was completely separated from the lower border of the mandible of dogs and then refixed to the original site. Bone scan and histologic examination were done at 1,2,3 and 4 weeks postoperatively. The bone scan after 1 week showed radioisotope uptake on the margin of the grafted bone and the isotope count was 21% compared to the uptake of the normal bone. After 2 weeks, the radioisotope uptake in the grafted bone increased to 52% of normal bone uptake. After 3 and 4 weeks, the degree of isotope uptake was 111% and 124% respectively. Histological findings after 1 week showed the absence of osteoblastic activity and 6 viable blood vessels in one 200X magnified field, which was 25% compared to the vessels of the normal bone. After 2 weeks, osteoblastic activities were noted and the number of viable blood vessels totalled 15, which was 63% of the vessels of the normal bone. After 3 weeks, osteoblastic activities increased and the number of viable blood vessels totalled 21, which was 88% of the vessels of the normal bone. After 4 weeks, there were markedly increased osteoblastic activities with a total number of 23 vessels, which was 96% of the normal bone. In summary, the revascularization of the membranous inlay bone graft began from the first week after bone graft, and then it gradually increased. After 3 weeks, the revascularization had returned to a nearly normal value compared with the value of the near-by normal mandibular bone.