| Objective:We utilized surgery-first approach (SFA) combining the postoperative rapid orthodontics to treat mandibular prognathism. To evaluate the surgical efficiency quantitatively and postoperative relapse, cephalometric and soft tissue analyses were conducted in all patients. All the results we obtained were to provide a reference and theoretical support for the treatment of mandibular prognathism by surgery-first approach.Methods:Seventy-two adult patients of mandibular prognathism treated in the Department of Maxillofacial Plastic Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences from September 2013 to March 2016 were included in this study. All the patients (including 40 cases of mandibular prognathism,28 cases of asymmetry mandibular prognathism and 4 cases of mandibular prognathism combining with maxillary retrusion)underwent the surgery-first approach and postoperative rapid orthodontics to correct the deformity of the jaw after communicating with the orthodontist. Lateral cephalometric radiographs of 68 patients(excluding maxillary retrusion cases) were taken in preoperative(TO),seven days after surgery(Tl) and postoperative follow-up(T2) to analyze the changes and relapses of hard tissue after the treatment. The soft tissue data of 12 patients were used with the Geomagic software to measure the changes after the treatment of surgery-first approach and analyze the relationship between the relapses of hard tissue and soft tissue.Results:During the 72 patients,18 cases occurred the phenomena of open-bite with 25% incidence after the surgery. All the phenomena were eliminated with the treatment of the elastic distraction after the surgery. All the patients got satisfactory appearance immediately after the surgery.The projects of SNB, ANB, FMIA, MP-LI and UI-SN which revealed the deformity of mandibular prognathism were significantly improved and tended to the Chinese normal range after the surgery and the postoperative rapid orthodontics. The time of postoperative rapid orthodontics last 5-16 months after surgery (average time 272±91.3 days).The malocclusion of the patients were also corrected after the treatment. The mean surgical setback was 8.67mm at B point and 8.96mm at pogonion on sagittal direction during the 68 patients (excluding maxillary retrusion cases). The mean long-term sagittal relapses were 1.79mm at B point and 1.99mm at pogonion with the relapse rate of 22% and 24.3%. The mean long-term vertical relapse distances were 1.63mm at B point,1.83mm at pogonion(P<0.05).We also observed that the asymmetry mandibular prognathism patients had higher relapse rates and ranges than the mandibular prognathism patients.The analyses of 12 patients’ soft tissue also proved the satisfactory treatment effect of the surgery-first approach. The mean surgical setback of mentolabial sulcus and pogonion of soft tissue was 6.81mm and 8.18mm.The chin had an obvious setback while the lower lip showed an outstanding descending. The chin and lip all had relapses on vertical direction, while only the chin had an advance relapse on sagittal direction. And no statistically significant relationships were observed between the relapses of hard tissue and soft tissue.Conclusion:The results of this study supported the clinical observation that surgery-first approach could effectively treat the mandibular prognathism, shorten the period of treatment. To evaluate the patients with postoperative effect of hard and soft tissue, we found the mandibular prognathism have significantly improved. Although relapses of the sagittal and vertical movements had been observed, the relapses were in an acceptable range within 2 mm. So we recommended to use surgery-first approach as one of the treatment choices to treat mandibular prognathism. |
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