The Clinical Research Of L-shaped Reduction Malarplasty Based On Digital Technology

ObjectiveReduction malarplasty has become one of the most famous aesthetic plastic surgeries during oriental females nowadays,and L-shaped reduction malarplasty is the most common used surgical method by plastic surgeons domestic and overseas.At present,the application of digital technology in clinic and scientific research of cranial-maxillofacial plastic surgery is increasing day by day.With the help of digital technology,this study can measure and analyze the form and function changes post L-shaped reduction malarplasty,then evaluating safety of this cosmetic surgery firstly.In addition,evaluating the effect of pre-bent Z-shaped titanium plate on narrowing of zygomatic arch in L-shaped reduction malarplasty,the feedback can lead to more sophisticated surgery.Furthermore,measuring the bone formation of zygomatic arch,which can reflex the fact of fracture union and provide a direction for bone grafting of zygomatic nonunion.MethodsChoosing cosmetic patients who had received L-shaped reduction malarplasty in our hospital and removed the titanium screws and plates at least 6 months post-operation as the object of study.Then reestablishing the CT images of pre-operation and post-operation via Materialise ProPlan CMF 3.0.Measuring 17 groups of data about length and angle in temporomandibular joint’s axial,coronal and sagittal planes.Then measuring altitude of pre-bent titanium plate,narrowing distance of zygomatic arch,and thickness of zygomatic arch both in pre-operation and post-operation.Designing osteotomy lines on zygomatic arch to get isolated zygomatic arch in the same anatomical place for volumetric reconstruction.Collecting pre-bent Z-shaped titanium plates with titanium nails for fixation of zygomatic arch,then a simulated surgery was performed on the wood strip,and the volume of pre-bent Z-shaped titanium plate with titanium nails on the bone surface was measured by applying draining method.And the difference is the bone formation of zygomatic arch.Finally,using Lane-Sandhu score standard to evaluate fracture union situation on X-ray films.Relevant data were analyzed via SPSS 22.0 statistical software.ResultsAccording to the measurement results of TMJ,Post-operative condylar anteroposterior diameter is longer in axial plane[(9.406±1.241)mm VS(9.259±1.276).mm],the difference is(0.146±0.388)mm.post-operative condylar anterior space,superior space and posterior space are smaller in sagittal plane[(1.080±0.537)mm VS(1.193±0.533)mm/(1.598±0.591)mm VS(1.907±0.755)mm/(1.239±0.568)mm VS(1.670±0.926)mm],the difference is(0.113±0.409)mm、(0.309±0.711)mm、(0.431±0.786)mm,other 13 measurements show no statistical significance.The altitude of pre-bent Z-shaped titanium plate is(3.802±0.819)mm,the unilateral narrowing distance of zygomatic arch is(3.211±0.817)mm,difference value is(0.591±0.409)mm,and the difference is statistically significant,the bilateral narrowing distance of zygomatic arch is(6.422±1.421)mm.The thickness of zygomatic arch both in pre-operation and post-operation are(4.648±0.752)mm and(3.791±0.715)mm,difference value is(0.857±0.573)mm,and the difference is statistically significant.Lane-Sandhu score of zygomatic arch is 9.620±2.529,surface volume of titanium plate and nail on zygomatic arch is 100 mm3,and bone formation of zygomatic arch is(163.183±370.757)mm3.ConclusionL-shaped reduction malarplasty will trigger slight changes to the form of TMJ,however TMJ can adapt this change and reach to a new balance due to compensated adaptation,the normal physiology function will not be impacted,surgery itself can be considered as a safe contour cosmetic surgery.The pre-bent Z-shaped titanium plate is not completely corresponding to the zygomatic arch narrowing distance in the actual application of reduction malarplasty,however it can control the narrowing distance of zygomatic arch relative accurately,and play the role of rigid internal fixatino and osteogenesis scaffolid,at the same time the operation time is saved and unnecessary injure are avoided.When poroma volume reaches(163.183±370.757)mm3 can get stable fracture union,not only can it reflex the fact of fracture union,but also it can provide reference for bone graft on zygomatic nounion.