Effect of cultured chondrocyte-seeded chondroitin-sulfate conjugated type I collagen scaffold on cartilage regeneration

PURPOSE: In this study, porous type I collagen scaffolds were cross-linked using dehydrothermal(DHT) treatment and/or 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide(EDC), in the presence and absence of chondroitin-6-sulfate(CS) and cultured autologous chondrocytes(Chondro) for cartilage regeneration. METHODS: Cartilage defects were created in the proximal part of the ear of New Zealand rabbits. Four prepared types of scaffolds(n=4) were inserted. The groups included Chondro-Collagen-DHT(Group 1), Chondro- Collagen-DHT-EDC(Group 2), Chondro-CS-Collagen- DHT(Group 3), and Chondro-CS-Collagen-DHT-EDC (Group 4). Histomorphometric analysis and cartilage- specific gene expression of the reconstructed tissues were evaluated 4, 8, and 12 weeks after implantation . RESULTS: EDC cross-linked groups 2 and 4 regenerated more cartilage than other groups. However, calcification was observed in the 4th week after implantation. CS did not increase chondrogenesis in all groups. Cartilage-specific type II collagen mRNA expression increased in the course of time in all groups. CONCLUSION: EDC cross-linking methods maintain the scaffold and promote extracellular matrix production of chondrocytes.

The Effect of Various Methods of Cross-linking in Type I Collagen Scaffold on Cartilage Regeneration

PURPOSE: Collagen is the principal structural biomolecule in cartilage extracellular matrix, which makes it a logical target for cartilage engineering. In this study, porous type I collagen scaffolds were cross-linked using dehydrothermal(DHT) treatment and/or 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide(EDC), in the presence and absence of chondroitin-6-sulfate(CS) for cartilage regeneration. METHODS: Cartilage defects were created in the proximal part of the ear of New Zealand rabbits. Four types of scaffolds(n=4) were inserted. The types included DHT cross-linked(Group 1), DHT and EDC cross- linked(Group 2), CS added DHT cross-linked(Group 3), and CS added DHT and EDC cross-linked(Group 4). Histomorphometric analysis and cartilage-specific gene expression of the reconstructed tissues were evaluated respectively 4, 8, and 12 weeks after implantation. RESULTS: The largest quantity of regenerated cartilage was found in DHT cross-linked groups 1 and 3 in the 8th week and then decreased in the 12th week, while calcification increased. Calcification was observed from the 8th week and the area increased in the 12th week. Group 4 was treated with EDC cross-linking and CS, and the matrix did not degrade in the 12th week. Cartilage-specific type II collagen mRNA expression increased with time in all groups. CONCLUSION: CS did not increase chondrogenesis in all groups. EDC cross-linking may prevent chondrocyte infiltration from the perichondrium into the collagen scaffold.

Measurement of the Skin Color Changes of Free Flaps by Chromometry

The distant free flaps have become the first choice for large, complex, complicated wounds. The skin of free flaps maintains its original color and texture with little or no change, but even these can develop some abnormal pigmentation and distant tissue does not match with recipient sites skin in color, texture, or thickness. To evaluate color changes of transferred flaps and color match with recipient sites in free flaps, we used Minolta chromameter with a L, a, b, color space recommmended by the CIE(Commission International de l'Eclairage). Eighteen patients(12 males and 6 females) who had undergone various free flap surgeries participated in the present study. The used free flaps included 5 first webspace free flaps or great toe free transfers, 5 free transverse rectus abdominis myocutaneous flaps, 2 free dorsalis pedis flaps, 2 free latissimus dorsi myocutaneous flaps, 2 free gracilis myocutaneous flaps, 2 free lateral arm flaps. The recipient sites for reconstruction were hand(n = 7), forearm(n = 4), lower leg(n = 3), foot(n = 2), breast(n = 2). In the 1st, 3rd, 6th, and 12th month after surgery, time-related colorimetric changes of the first webspace free flaps or great toe free transfers for thumb and first webspace reconstruction(n=5) showed a decrease in L(lightness). The a(redness), b(yellowness) value of the flap were not significantly changed. The skin color changes of the transferred flaps to sun unexposed recipient sites(breast) were less than those to sun exposed recipient sites(hand, forearm, lower leg). These indicate probably because of the greater quantity of pigment in sun exposed skin flaps. Also,in total color difference of the transferred flaps and recipient sites, free transverse rectus abdominis myocutaneous flaps for breast reconstruction was lower than the other flaps. Measuring skin color of the planned flap and recipient site before surgery and management of sunlight exposure of the recipient site are very helpful guides to obtain a good color match in reconstructive surgery.

A Correction of Hypoplastic Alar Nasi in Cleft Lip Nose Deformity : Using A Subcutaneous Reduction of Ala and External Lateral Triangle of the Non-Cleft Side

One of the problems in the correction of the cleft lip nose deformity is the hypoplastic alar nasi on the affected side, even after secondary rhinoplasty. This deformity was managed with various cartilage grafts for augmentation of the cleft side, but that procedures have been complicated by inadequate cartilage augmentation, complex procedure, unpredictable results. To overcome the problem of the hypoplastic alar nasi, the authors used subcutaneous reduction of the upper part of the ala and external lateral triangle on the non-cleft side through the intranasal approach. Additional techniques including partial-thickness incisions of the septal cartilage, freeing of the septal cartilage from the vomer, the nasal osteotomy, a z-plasty on the affected plica vestibularis and cinching of denuded alar base of the affected side or an interalar cinch were also used to repair individual differences of the nasal deformities. The authors performed 20 cases (11 women and 9 men) of the correction of the unilateral cleft lip nose deformity between 1997 and 1999. The patient, ranged in age from 19 years to 51 years at the time of surgery, with a mean age of 24 years. Eight to twenty (mean twelve) months postoperatively, the patients were evaluated by the ordinary scale method and the photogrammetric measurements using preoperative and postoperative photos. All the patients showed uneventful healing except two cases of superficial skin necrosis. By the ordinary scale method, "good" aesthetic results were noted. By the photogrammetric measurement, the alar height of non-cleft were significantly decreased. The results showed a relatively symmetrical alar height index of both cleft and non-cleft sides. In conclusion, the procedure is very simple and fast to perform, and it is easy to achive nasal symmetry. It is possible to use the procedure with additional techniques in the various deformities for the better results.

A Correction of Hypoplastic Mandible Using Mandibular Shape Porous High Density Polyethylene (PHDPE)

The mandible with the lower maxilla comprises the lower third of the face. A correction of the mandible in facial asymmetry would be helpful in improving aesthetic appearance. In general, surgical techniques for improving the contour of lower jaw deformities include correcting the deficient mandible by osteotomies, distraction osteogenesis and the augmentation of the mandible with alloplastic or autogenous materials. In a patient with satisfactory occlusal relationships and mild hypoplasia, alloplastic material for augmentation of the mandible on the affected side is more practical than autogenous augmentation. The porous high density polyethylene (PHDPE) implant is a widely available alloplast which is an attractive alternative to other alloplasts and autogenous tissues. Thirteen patients (8 men, 5 women), ages ranging from 17 to 47 years old, have types IA (n = 6) and IB (n = 5) hemifacial microsomia(Munro and Lauritzen, 1985), Klippel-Feil syndrome (n = 1), Romberg's disease (n = 1) were corrected with prefabricated porous high density polyethylene over a 4 year period (1996- 1999). The average follow-up period was 12 months, however the range has been between 6 and 36 months. Preoperative planning was done based on an aesthetic assessment of thickness of the soft tissue, the use of life size photographs, cephalometric and panorex x-rays and three dimensional computed tomography. The surgical technique consists of an intraoral approach incision, the an implant was placed subperiostealy, appropriately sculptured and fixed to posterior and inferior border of the mandible at the gonial angle. In four patients the implant had to be removed due to complications which included three cases of infection and one case of extrusion by iatrogenic trauma. One of the above four patients' implant was replaced with a smaller one, approximately 3 months after its removal. With the others nine patients there was no infection or permanent morbidity. Postoperative appearance was considered very satisfactory, the mandible was well outlined, and the facial proportions were improved. Porous high density polyethylene implant is recommended for hypoplastic mandible augmentation when proper indication are strictly observed and surgical steps are accurately followed.