| Objectives1.An accurate quantitative evaluation system for alveolar cleft reconstruction via digital Technology to achieve accurate preoperative assessment of the alveolar cleft,precise intraoperative repair of the osseous defect,and exact postoperative evaluation of the outcome of the reconstruction.2.Based on accurate quantitative evaluation system for alveolar cleft reconstruction via digital Technology,and to investigate how recombinant human BMP-2(rhBMP-2)affects the results of alveolar cleft autologous bone grafting.3.Prospective,randomized controlled clinical trial was conducted,to verify the effect of autogenous bone marrow concentrate blood combined with ?-TCP scaffold in the treatment of alveolar cleft bone defect is not inferior to that of autogenous iliac cancellous bone graft.4.The animal model of alveolar cleft was established to satisfy the study of the mechanism of bone graft repair and the effect of different biomaterials in the repair of alveolar cleft bone defects.The establishment of a reliable evaluation method which is convenient for subsequent basic research.Methods:1.A retrospective study was conducted on 26 patients who received the secondary alveolar bone grafting(SABG)at our center from December 2016 to December 2018.The preoperative CT data of 26 patients were analyzed digitally.The alveolar cleft defect volume was measured by the mirror-reversed technique and the subtraction method.The accuracy,consistency and interobserver reliability of the two measurement methods were analyzed and compared.2.The osteogenic effect of 26 patients who received autogenous ICBG or rhBMP-2 combined with ICBG to repair alveolar cleft was evaluated.Helical computed tomography images were obtained preoperatively and 12 months postoperatively.The datasets were reconstructed as 3D images using Mimics software,and were processed using Geomagic Wrap.The newly formed bone of the alveolar cleft was segmented by identifying the differences between pre-and postoperative 3D images.The accuracy,validity and reproducibility of the method were verified by statistical analysis.3.Patients who underwent SABG at the Plastic Surgery Hospital of Chinese Academy of Medical Sciences between January 2019 and August 2020,20 patients were enrolled according to the inclusion and exclusion criteria.After signing the informed consent form,they were randomly enrolled into the two surgical methods group through the central randomization system:10 cases of autogenous Bone marrow concentrate blood combined with ?-TCP scaffold group,10 cases of autogenous ICBG group.Aderse events and iliac donor area pain scale were assessed 5 days and 1 month after surgery;CT scan of the head was performed 6 and 12 days after surgery.After follow-up,3D imaging analysis was performed,and evaluating defect repair and graft changes.4.12 experimental rabbits were randomly divided into three groups.The right alveolar ridge fissure defects of different sizes were made by surgical methods and the left central incisor was extracted.The central incisor side:4mm defect;Group A:6mm defect;Group B:8mm defect;Group C:10mm defect.8 weeks after operation,the self-repair of the rabbit alveolar cleft was observed by 3D reconstruction and gross anatomy,and the defect size of the standard rabbit alveolar cleft model was determined.After the establishment of alveolar cleft model in 18 experimental rabbits,they were randomly divided into 2 groups.The same amount of autogenous iliac cancellous bone and the same amount of ?-TCP were implanted,respectively.At the 2nd,4th and 8th week after operation,3 rabbits in each group were randomly selected and sacrificed for cranial CT scan.Anatomical and histological observations were made on the rabbit model of alveolar cleavage,and the trabeculae,blood vessels and hematopoietic tissues,and osteoclasts were observed.Results1.The mean alveolar defect volumes in the 20 patients were 1.29±0.31 cm3 as determined by the mirror-reversed technique and 1.22±0.35 cm3 as determined by the subtractive method,and the respective mean calculation times were 11.93±1.75s and 9.52±1.24s.There was a strong positive correlation between the volumes measured using the two methods(r=0.904,p<0.05).In paired Student's t-test analysis,there was no significant difference between the values derived using the two methods(p>0.05).In Bland-Altman analysis there was agreement between the mirror-reversed technique and subtractive method for alveolar cleft-related measurements.The ICC of the two observers was 0.966 for the mirror-reversed technique and 0.980 for the subtractive method.2.There were no significant differences between the ICBG group and the BMP group regarding sex(p=0.899)or age(p=0.919)of patients.The mean defect volume in the 26 patients was 1.25±0.32 cm3.In the ICBG group(n=12),the newly formed bone volume ranged from 0.25 to 0.88cm3(mean=0.52±0.20 cm3)and the mean bone formation percentage was 42.01±15.57%.In the BMP group(n=14),the newly formed bone volume ranged from 0.34 to 1.09 cm3(mean=0.69±0.21 cm3)and the bone formation percentage was 55.79±11.84%.There was a statistically significant difference between the ICBG group and the BMP group in terms of postoperative bone formation percentage(p=0.022).The ICC between the newly formed bone volume measured by two observers was 0.923,the ICC betw een two measurements was 0.948 of observer LB,and 0.939 of observer LBH.3.20 patients with unilateral alveolar cleft were enrolled in our hospital,and the average preoperative defect volume was 1.27±0.32cm3.The mean pain scale scores of the experimental group at 5 and 30 days after surgery were 1.2±0.87 and 0.3±0.64 points.The mean pain scores of the control group at 5 and 30 days after surgery were 4.1±0.94 and 1.1±0.83 points.There were statistically significant differences in pain scores between the two groups 5 days and 30 days after surgery.Experimental group,the average volume of newly formed bone at 6 months after surgery was 0.65±0.24cm3,BF%was 57.66±17.95%;The average volume at 12 months after operation was 0.52±0.18cm3,BF%was 52.3 8±14.37%.Control group:the average volume of new bone at 6 months after surgery was 0.74±0.14cm3,BF%:52.13±15.73%;The average volume of newly formed bone at 12 months after surgery was 0.68±0.23cm3,BF%:48.06±21.10%.There was no significant difference in the proportion of repair between the experimental group and the control group at 6 and 12 months postoperatively.4.In the central incisor group(4mm),the alveolar fossa defect healed completely.6mm group:the osteogenesis in the alveolar modeling site was good,and the bone defect was close to healing.The average defect volume was 48.75±11.65mm3.In the 8mm group,the bone wall of the alveolar modeling site had obvious pit bone defect,the average defect volume was 97.94±13.94mm3;10mm group,the bone wall pits of the alveolar modeling site were obvious,and the height of the alveolar ridge was decreased obviously.The average defect volume was 175.16±23.00mm3.In the ICBG group,the bone absorption rate was 17.21±2.62%,37.61±4.74%,22.48±10.59%for 2 weeks,4 weeks and 8 week s after operation,respectively.In ?-TCP group,the bone absorption rate was 17.78±1.74%,33.77±12.22%,21.95±5.16%for 2 weeks,4 weeks,8 weeks after operation,respectively.There was no significant difference in bone absorptivity between the autogenous iliac crest group and the ?-TCP group at 2,4,and 8 weeks postoperatively.Conclusions1.The accurate quantitative evaluation system for alveolar cleft reconstruction via digital Technology is characterised by high precision,clinical convenience,time efficiency,and high reproducibility.Compared with the mirror-reversed technique,the subtraction method has broader potential applicability,and better simulates intraoperative bone grafting.2.rhBMP-2 combined with autologous bone grafting results in a higher bone formation ratio than autologous bone grafting alone in alveolar cleft reconstruction.3.The osteogenic effect of BMC combined with ?-TCP scaffold in repairing alveolar cleft defect was similar to that of autogenous iliac cancellous graft,and the length of hospital stay and postoperative pain in the iliac bone region were significantly reduced compared with the control group.4?The operation of 10mm×5mm rabbit alveolar ridge defect can establish a sufficiently large,stable and reliable alveolar ridge cleft model.Digital measurement and immunohistochemical analysis are effective methods to evaluate the effect of bone repair in rabbit alveolar cleft model. |
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