Abstract
Using growing rabbits, the septal cartilage was resected either simply without any other treatment or with insertion of autograft, incision, or destruction, and observations were made for development of cartilage regeneration or septal deviation following the operation.
Simple resection was performed for the following seven sites: upper, middle, lower, anterior and posterior areas as well as extended areas (lower end is either conserved or resected). Following simple resection, cartilage regeneration starts from about 1 week after the operation corresponding to the site of resection, with regenerated cartilage filling all the area at 4 week, if the perichondrium is conserved. Septal deviation after simple resection begins to appear in association with cartilage regeneration, and it almost completes at 8 weeks after resection. Incidences of septal deviation as classified by resection site in animals fed for 8 and 16 weeks were 7/11 cases (63.6%) for the upper area, 2/8 cases (25%) for the middle area, 2/4 cases (50%) for the lower area, 3/5 cases (60%) for the anterior area, 4/6 cases (66.7%) for the posterior area, 6/8 cases (75%) for the extended area with conservation of the lower end and 0/4 cases (0%) for the extended area with resection of the lower end. Thus, the incidence of septal deviation was lowest after resection of the middle site.
Results obtained after insertion of autograft were compared with findings of adult rabbits. In growing animals union between the existing cartilage and the gafted cartilage was seen from the early stage, while in adults rabbits no such findings were obtained. It is considered that septal deviation occurs due to imbalance caused by difference in cartilage stroma between existing cartilage and grafted cartilage as well as the presence or absence of an increasing tendency. It appears more remarkably in growing rabbits (3/3 cases or 100%) than in adult animals (4/8 cases or 50%).
Animals incised of the cartilage showed no change with growth similar to that observed in control animals.
In animals with destruction, regenerated cartilage appeared evenly from the left and right perichondrium with the destructed cartilage fragment as the center, showing no septal deviation was seen.
As the possible mode of cartilage regeneration, the following three are considered according to the septal condition.
A: Cartilage is regenerated continuously from the perichondrium
B: Cartilage is regenerated as if the area surrounded by cartilage and perichondrium is filled with cartilage inducing substances.
C: Cartilage is regenerated by cartilage inducing substance in an island shape in the area with sparse connective tissue.
In this case the regenerated cartilage well reproduces the condition before resection.
