Evaluation Of Clinical Effects Of Digital Technology In The Repair Of Mandibular Defects With Free Fibula Flap

The mandible is the largest bone that forms the maxillofacial region.It is also the only movable bone in the maxillofacial region.It is located in the lower third of the face The mandibular bone supports the facial shape and participates in chewing,pronunciation and aesthetic functions.Tumor,trauma,infection and other factors will cause the continuity of the mandible to be damaged,which will affect people's aesthetics,pronunciation,chewing,swallowing and other functions,and cause severe psychological pressure on patients.Since Hidalgo first applied the free fibula flap to the repair and reconstruction of jaw defects,the vascularized bone tissue flap represented by the fibula flap has become the most important method for mandibular defect repair.However,the application of traditional free fibula flap has disadvantages such as high sensitivity of the surgical technique,long operation time,and difficulty in achieving accurate repair and reconstruction.The emergence of digital technology can effectively solve the above problems,and through digital technology,the quantitative evaluation of traditional clinical effects can be achieved,which has made great progress in the evaluation of clinical effects.In this experiment,the clinical effect of free fibula flap repair and reconstruction of mandible was evaluated by digital analysis using retrospective analysis.This experiment is divided into three partsPart 1:Precision analysis of domestic digital software E-3D in 3D reconstruction of medical imagesObjective:To analyze the accuracy of E-3D in 3D reconstruction of digital medical images and anatomical measurement with reference to traditional digital software mimics.Methods:Three cases of skull MSCT in our hospital from September 2017 to September 2019 were selected.Based on the 3D model reconstructed by Mimics software,the deviation analysis of digital software E-3D reconstruction 3D model was performed.The basic image data was imported into two softwares in DICOM format for three-dimensional model reconstruction,and the three-dimensional reconstruction model was imported into the fitting analysis module of the two digital softwares,and the accuracy of the fitting analysis of the two software reconstruction three-dimensional models was compared;Two cases of 3D reconstruction of the skull were measured at 8 specific distances and 2 specific angles,and the differences between the two software measurement functions were analyzed.Results:Three groups of three-dimensional skull reconstruction models were obtained using Mimics and E-3D software.The mean deviation ± standard deviation were(0.01 ±0.15)mm,(0.01 ± 0.16)mm,and(0.01 ± 0.33)mm.The time is 13S,14S,25S,24S,25S,25S.The surface areas of the 3D reconstruction model are:skull 1 2017.01cm2,2144.47cm2,skull 2 3046.77cm2,3059.92cm2,skull 3 3033.41cm2,3025.96cm2,and the overall deviation of the fitness analysis is:skull 1 0.01mm,0.01mm,skull 20.01mm,0.01mm,skull 3 0.02mm,0.02mm.For the three-dimensional reconstruction models of the two groups of skulls,there was no significant difference in the three-dimensional distance and angle measurement between the two digital medical softwares of E-3D and Mimics(P>0.05);Conclusion:Compared with Mimics digital software,E-3D has no obvious differences in 3D reconstruction effect and 3D distance measurement accuracy,and has the advantages of low price and simple operation.E-3D can be used for 3D reconstruction and measurement of clinical image data.Part 2:the precision study of digital guide plate combined with nailway transfer technology in the reconstruction of mandibular defect with free fibula flap.Objective:Applying digital guide plate made by CAD/CAM technology and nail channel transfer technology to the reconstruction of free fibula flap to repair mandibular defect.The accuracy of preoperative design and postoperative actual effect was analyzed.Methods:Six patients were treated in our department from September 2017 to September 2019 and applied digital technology to repair mandibular defects with free fibula flaps,including 4 patients with ameloblastoma and 2 patients with mandibular gingival cancer.All patients underwent thin-layer maxillofacial and double-limb CT examinations before operation.The data was sent to Putianyang for digital virtual design in DICOM format.Rapid prototyping technology was used to make osteotomy guides,and pre-curved reconstruction boards containing nail channel transfer technology were used.During the operation,the osteotomy guide was used to remove the mandibular lesion,to prepare the fibula flap,and to position and fix the fibula flap.One week after the operation,the patient's maxillofacial spiral CT was taken.The E-3D digital software was used to perform three-dimensional reconstruction and measurement of the mandibular reconstruction of the fibula.The STL file designed before surgery and the STL file of the three-dimensional reconstruction model after surgery were imported into 3-matic research 9.0 performs a fit analysis to verify the accuracy of digital surgery.Results:The bilateral condylar distances before and after fibula reconstruction surgery were 123.71 ± 8.35mm,125.26 ± 6.90mm(P=0.247),and the bilateral mandibular angle distances were 104.16 ± 5.83mm and 101.27 ± 5.58mmm(P=0.94).The angle of the mandibular angle of the affected side was 126.06 ± 6.48°,124.67 ± 7.28 °(P=0.162),and the angles of the bilateral condyles were 63.69 ± 4.88° and 64.30 ± 4.63°(P=0.533).There was no significant difference in the above results.(P>0.05).The distance error of bilateral condyle before and after fibula reconstruction was 2.76 ±1.47mm,the distance error of bilateral mandibular angle was 2.5mm ± 1.86mm,the angle error of affected mandibular angle was 1.98 ± 1.4°,and the error of bilateral condyle angle was 1.98 ± 0.85°,the mandibular buccal cutting error is 1.50 ± 1.21mm,and the mandibular lingual cutting error is 2.05 ± 1.00mm.The overall error of the reconstructed end of the mandible was 1.38 ± 1.00mm,and the maximum displacement of the condyles on the affected side was 7.91 ± 3.79mmConclusion:In this experiment,we used a digital guide plate combined with a nail-channel transfer technique to repair and reconstruct the mandibular defect,which further improved the accuracy of the operation.Digital guide plate combined with nailway transfer technology is a simple and effective method,which provides repeatable accuracy and accuracy for mandibular reconstruction and reconstruction of free fibulaPart 3:Application of digital technology in follow-up evaluation of mandibular defect repairObjective:To evaluate the changes of mandibular morphology and position using digital technology during the follow-up of mandible repair with free fibula flap Methods:A total of 4 patients were admitted to our department from September 2017 to September 2019 and applied digital technology to repair mandibular defects with free fibula flaps,including 3 patients with ameloblastoma and 1 patient with gingival cancer of the mandible.The patients were followed up for six months after operation,and the maxillofacial MSCT was photographed.E-3D digital software was used to perform 3D reconstruction of MSCT before surgery,1 week after surgery and 6 months after surgery It was imported into 3-matic research 9.0 software in STL file format for fitting analysis Changes in the shape and position of the mandibleResults:?The morphological measurement results of the condyles on the uninvolved side:the inner and outer diameters of the condyles were 20.74 ± 0.59mm,20.57 ±0.35mm,20.48 ± 0.75mm before operation,1 week and 6 months after operation(P>0.05)The condylar diameters were 10.14±1.27mm,10.01±1.38mm,9.80±1.49mm(P>0.05),and the height of the condylar head was 16.35 ± 1.29mm,16.27 ± 1.03mm,16.21 ± 1.09mm(P>0.05),the condylar volumes were 1.41 ± 0.33 cm3,1.42 ± 0.22 cm3,and 1.48 ± 0.26 cm3,respectively(P>0.05).?Mandibular measurement results The length of the affected mandibular branch before surgery,1 week and 6 months after surgery were 57.94 ± 4.07mm,55.86 ± 5.42mm,53.88 ± 6.74mm(P>0.05),and the mandibular branch of the healthy side The lengths were 56.86 ± 5.77mm,56.85 ±5.74mm,56.92 ± 5.90mm(P>0.05),and the distance of bilateral condyles were 113.48± 8.89mm,115.05 ± 8.17mm,and 113.89f ± 8.53mm(all P>P>0.05),and the bilateral mandibular angle distances were 108.00 ± 5.94mm,105.60 ± 5.17mm,and 105.20 ±5.49mm,respectively(P>0.05).?Fitness results:The error of the whole mandible in 4 patients(1 week before VS)was:0.88±0.77mm,1.36±1.10mm,1.90±1.97mm,1.23± 1.07mm;6 months after VS)The errors were:0.57 ± 0.48mm,1.28 ± 0.95mm,1.57 ±1.84mm,1.43 ± 1.24mm;the errors of the affected condyles(1 week before VS after surgery)were:1.09 ± 0.93mm,2.01 ± 1.46mm,2.23 ± 1.65mm,3.61 ± 2.45mm;the errors of the ipsilateral condyles(6 months before VS after surgery)were:0.57 ±0.36mm,1.06 ± 0.96mm,1.68 ± 1.51 mm,2.29 ± 1.37mm;errors on the contralateral condyle(preoperative vs.1 week after surgery)were:0.54 ± 0.40mm,1.26 ± 0.95mm,0.96 ± 0.74mm,1.41 ± 0.92mm;6 months after VS)The errors were:0.42 ± 0.30mm,1.46± 1.03mm,1.05± 0.85mm,1.41± 0.76mm.Conclusion:After reconstruction of mandibular defect using reconstructed titanium plate,due to the guidance of occlusal and masticatory muscles,the affected condyles will be displaced to the original position,and the uninvolved condyles and the whole mandible will be affected by the affected side.The displacement of the condyles occurs in a compensatory rotational shift.The direction of the rotational displacement is determined by the direction of the affected condyle.The affected mandibular angle will be partially absorbed due to stress concentration and poor blood supply.The reconstructed mandible is in a stable state as a whole,with good symmetry,without extensive reconstruction or absorption.Digital three-dimensional measurement technology is an objective and effective method,which helps us analyze the law of alterations in mandibular reconstruction after surgery,and at the same time feedback and guide clinical surgery,which can effectively improve the accuracy of surgery and restore the patient's good facial shape and Physiological function.