A nasal critical-size defect: an experimental model for the evaluation of facial osseous repair techniques.

OBJECTIVE

To create a standardized nonhealing defect of craniofacial, minimal load-bearing, endochondral type bone with geometric properties that are amenable to quantitative and biomechanical testing that can be used to develop new osteoconductive and osteoinductive engineering repair techniques.

DESIGN

Before-and-after randomized trial of an anatomical description.

SUBJECTS

Twenty-four retired male breeder Sprague-Dawley rats.

METHODS

A standardized osseous defect was created by removing the nasal bones with a cutting burr to the level of the nasal mucosal membranes. The defects were not repaired, and groups of 8 animals were examined using planimetry, computed tomographic scanning, and histological analysis at 1, 3, and 6 months following surgery to quantify defect repair.

RESULTS

Mean repair rate by surface area measurements at 1, 3, and 6 months was 5.75%, 4.89%, and 7.09%, respectively. Results from histological analysis revealed that the defects were filled with fibrous tissue. Computed tomographic scans showed the bone defect without repair.

CONCLUSION

This nasal osseous defect fulfills criteria to be considered as a critical-size defect that can be used to investigate new techniques for bone reconstruction.