Histomorphometric analysis of the porcine mandibular distraction wound.

PURPOSE: To analyze the sequence of histomorphometric changes in the regenerate during distraction osteogenesis (DO) of the minipig mandible. MATERIALS AND METHODS: A total of 16 minipigs underwent unilateral mandibular DO using a protocol of 0-day latency and a 1-mm/day rate for 12 days, and 24 days of fixation. The mandibles were harvested at mid-DO, end-DO, mid-fixation, and end-fixation. An additional 2 minipigs underwent acute lengthening, and 1 sham control was included. Serial gross examinations and plain radiographs were performed before paraffin embedding. The sections were stained with hematoxylin-eosin or hematoxylin/alcian blue/sirius red stain. Histomorphometric analysis was performed to determine the percentage of surface area (PSA) occupied by hematoma, fibrous tissue, cartilage, and bone. RESULTS: All 19 minipigs survived the operation, and 17 survived the observation period; 2 were killed because of infection (mid-DO, n = 1 and end-fixation, n = 1). No device failures occurred. Of the 17 specimens, 4 were at mid-DO, 4 at end-DO, 4 at mid-fixation, and 2 at end-fixation; 2 were in the acute lengthening group, and 1 was the sham control. Hematoma was present only at mid-DO (16.61 +/- 8.07 PSA) and end-DO (1.17 +/- 2.33 PSA). Fibrous tissue decreased from mid-DO (53.12 +/- 8.59 PSA) to end-fixation (25.00 +/- 0.83 PSA). Cartilage was present in end-DO (1.72 +/- 2.71 PSA), mid-fixation (5.82 +/- 6.64 PSA), and acute lengthening (1.43 +/- 0.95 PSA). Bone increased from mid-DO (25.18 +/- 0.99 PSA) to end-fixation (64.89 +/- 0.79 PSA) and occurred earlier in the superior and middle thirds of the wounds. Periosteal bone formation predominated over endosteal bone formation early in distraction. CONCLUSION: The results of the present study indicate that bone formation in this model consists of both intramembranous and endochondral components, with intramembranous osteogenesis predominating. Bone formation occurred earlier in the superior/middle portions of the wound, possibly owing to osteoinductive properties of developing tooth buds and the inferior alveolar nerve, respectively.

Condylectomy and costochondral graft reconstruction for treatment of active idiopathic condylar resorption.

PURPOSE: The purpose of this study was to evaluate the outcomes in patients with active bilateral idiopathic condylar resorption treated by condylectomy and costochondral graft (CCG) reconstruction. PATIENTS AND METHODS: This was a retrospective evaluation of 15 consecutive patients treated at Massachusetts General Hospital from 1999 to 2004 who had: 1) active bilateral idiopathic condylar resorption confirmed by clinical examination, plain radiographs, and technetium-99 bone scan; 2) adequate documentation; and 3) a minimum of 12 months follow-up. Patients with an identifiable cause of condylar resorption such as rheumatoid or degenerative arthritis, trauma, or steroid use, or who had less than 12 months follow-up were excluded. Preoperative, immediate postoperative, 6-month, 12-month, and latest follow-up clinical examinations, lateral cephalograms, and panoramic radiographs were used to evaluate the outcomes. Inferior alveolar and marginal mandibular nerve function, jaw motion, and occlusion were evaluated by history and physical examination. All patients underwent bilateral condylectomy and CCG reconstruction. RESULTS: There were 13 female and 2 male patients with a mean age of 24 years. Mean follow-up was 34 months (range, 12 to 84). Preoperatively, all patients had Class II malocclusion: mean overjet 6.2 mm and mean anterior open bite -2.65 mm. At latest postoperative follow-up, all patients showed Class I occlusion with no anterior open bite, a stable and reproducible occlusion, and a normal range of TMJ motion with a mean maximal incisal opening of 39 mm. CONCLUSION: The results of this study indicate that a stable and satisfactory outcome is achievable in patients with active idiopathic condylar resorption treated by condylectomy and CCG reconstruction.