Cartilage generation using alginate-encapsulated autogenous chondrocytes in rabbits.

In this study, we investigated the possible use of calcium alginate as a matrix for cartilage generation with autogenous chondrocytes, and examined whether the generated cartilage could keep its original volume over time when used as an implant for filling and contour restoration in the host body. Biodegradable, biocompatible, and injectable calcium alginate impregnated with isolated autogenous chondrocytes from the auricle was injected into the gluteus muscle of 12 New Zealand White rabbits. The volume of injected calcium alginate was always 3 mL, and the density of chondrocytes was 10 x 10(6) cells per milliliter. At 4 weeks (short-term period, n = 6) and 20 weeks (long-term period, n = 6) after injection, the histologic findings and the volume of the generated cartilaginous nodules were analyzed. At the time of harvest, 10 of the 12 specimens revealed findings characteristic of natural cartilage. However, histologic examination demonstrated scanty vascular and fibrous tissue ingrowth. Many osteoid matrices, including marrow-like cells, were noted in the vicinity of the neocartilage. The approximate original volume of the injected material was maintained over 20 weeks. These results suggest that although complete cartilage replacement was not always achieved, calcium alginate-autogenous chondrocytes may represent an injectable implant that can generate new autogenous fibro-osteo-cartilaginous tissue for volume augmentation.

Orbital floor and infraorbital rim reconstruction after total maxillectomy using a vascularized calvarial bone flap.

A number of techniques have been introduced to support the orbital floor after maxillectomy without orbital exenteration. These methods include skin graft or muscular sling, but they have resulted in severe complications, such as enophthalmos, global ptosis, diplopia, and facial deformity. Currently, advanced microvascular reconstruction using bone and soft tissue is performed by many surgeons. This usually results in the filling of the postmaxillectomy defect, but the lack of support for the orbital rim and floor by the bone flap may still cause the complications mentioned above. Vascularized calvarial bone flap was chosen in this study for reconstruction of the orbital floor and infraorbital rim to function as a buttress, to reconstruct recipient sites of poor vascular bed after radiation therapy, and to withstand further postoperative radiation. By providing a solid floor and rim, these complications can be prevented with satisfactory function and aesthetically acceptable results. From September of 1995 to July of 1998, we performed vascularized bone flap for the reconstruction of the orbital floor and infraorbital rim in four cases after total maxillectomy involving the orbital floor. With a follow-up period from 19 to 35 months (mean, 27 months), we obtained significant improvement of functional and aesthetically acceptable results without global ptosis, enophthalmos, diplopia, or severe facial contour deformity.