The Effect Of Intraoperative Three-dimensional Scanning Technique On Evaluation Of Breast Symmetry In Reduction Mammaplasty

BackgroundBilateral breast symmetry plays a decisive role in reduction mammaplasty,and precise intraoperative symmetry evaluation is the key to determine postoperative breast symmetry and aesthetic results.In addition to simple measuring methods can provide limited objective data,it depends mostly on the surgeons' experience that may be biased by individual subjective factors.With the development of computer technology,digital image acquisition equipment and optical elements,three-dimensional(3D)scanning technique can quickly acquire and reconstruct 3D images of breasts in a non-contact manner.This technique can precisely assess the breast morphology from many aspects,such as linear distance,surface,volume and so on.It is an advanced breast morphology measurement method,and has been widely used before and after reduction mammaplasty.Through the literature review,there has been no study of the intraoperative application of 3D scanning technique in breast surgery.Currently-available stationary 3D scanning systems are usually so bulky that the scanning range will be limited because of static placement,which are not suitable to be placed in the complex environment of a surgical room,let alone to realize flexible scanning during operations.In the current study,a new hand-held 3D scanning system(INOVA system)is applied to assist intraoperative symmetrical assessmeot,aiming to achieve better aesthetic results in reduction mammaplasty.Before intraoperative application,it is necessary to determine the exactness and reproducibility of this method.Comparing with direct anthropometric measurement and JR 3D scanning system,it will find out whether INOVA system has the comparable accuracy,repeatability,and usability in breast surface imaging.The study also examined the effect of respiratory movements of the chest on breast 3D images.Finally,it is necessary to confirm the feasibility and effectiveness of intraoperative 3D scanning technique on evaluation of breast symmetry in reduction mammaplasty.This study can provide a new idea for the combination of 3D scanning technology with breast plastic and reconstructive surgery.Objectives1.By analyzing the correlation and consistency between INOVA system and the direct anthropometric method in the measurements of many key breast linear parameters,it aimed to determine whether INOVA system could precisely obtain the 3D breast images of the participants.2.By comparing the correlation and consistency between INOVA system and JR system in the measurements of many key breast linear parameters,as well as the analysis of the 3D deviation between the breast images obtained by the two systems in the same participant,its aim was to clarify whether the 3D images obtained by INOVA system could be comparable to JR system's.3.To analyze whether respiratory movements significantly affect the breast surface imaging of INOVA system,we did the 3D deviation analysis between different breast 3D images.In addition,the test-retest reliability of many key breast linear parameters in breast 3D images was calculated,which was to assess the repeatability of INOVA system under eupnea.4.Based on INOVA system,the study was to demonstrate the feasibility and effectiveness of intraoperative 3D scanning technique on evaluation of breast symmetry in reduction mammaplasty.Methods1.The preoperative and postoperative patients were prospectively enrolled in the study.Multiple linear distances,such as Sn-N(surface distance),N-N(Euclidean distance),N-IMF(surface distance),N-M(surface distance)and BW(Euclidean distance),were measured by the direct anthropometric method and INOVA system,respectively.Spearman correlation coefficient and regression analysis were used to show the correlation between the measurement results of the two different methods,and Bland-Altman plot was used to evaluate the consistency of the measurement results.2.The preoperative and postoperative patients were prospectively enrolled in the study.Multiple linear distances,such as Sn-N(Euclidean distance),N-N(Euclidean distance),N-IMF(Euclidean distance),N-M(Euclidean distance),BW(Euclidean distance),Sn-N(surface distance),N-M(surface distance)and N-IMF(surface distance),were measured by INOVA system and JR system,respectively.Pearson correlation coefficient and regression analysis were used to show the correlation between the measurement results of the two systems.The Bland-Altman plot was used to evaluate the consistency of the measurement results.The root mean square error(RMSE)between the 3D breast images obtained by the two systems in the same participant was calculated by the best fitting algorithm and 3D deviation analysis,which aimed to analyze the comparability of NOVA system and JR system.3.The preoperative and postoperative patients were prospectively enrolled in the study.Four breast 3D images of three respiratory states(2 under eupnea,1 under natural end-expiratory and 1 under natural end-inspiratory)were obtained by INOVA system.The best fitting algorithm and 3D deviation analysis were used to calculate the RMSE between two different 3D images to analyze the effect of respiratory movement on the breast surface imaging of INOVA system.The correlation coefficient was used to analyze the test-retest reliability of many key linear distances,such as Sn-N(Euclidean distance),N-N(Euclidean distance),N-IMF(Euclidean distance),N-M(Euclidean distance),BW(Euclidean distance),Sn-N(surface distance),N-M(surface distance)and N-IMF(surface distance),between two different breast 3D images both under eupnea,which was to calculate the repeatability of INOVA system under eupnea.4.Female patients with bilateral breast hypertrophy were enrolled retrospectively and prospectively.The participants in the study group routinely received intraoperative symmetry evaluation based on INOVA system.Through the quantitative evaluation of bilateral breast volume,NAC position and IMF height,the operator could adjust the objectively identified breast asymmetry according to the measurement results.However,the participants in the control group did not undergo 3D scan evaluation during operation,and the intraoperative breast symmetry was heavily dependent on surgeon's visual estimations.According to the two-dimensional and 3D image data of the patients 3 months after operation,the two-dimensional and three-dimensional breast symmetry were evaluated by observer-reported evaluation and 3D measurement method respectively,and the feasibility and effectiveness of intraoperative 3D scanning technique on evaluation of breast symmetry in reduction mammaplasty was validated.Results1.A total of 54 participants were enrolled with an average age of 31.39 years,and BMI was between 15.59 and 31.89 kg/m2.Correlation coefficient,linear regression analysis and Bland-Altman plot were used to evaluate the correlation and consistency between the direct anthropometric method and INOVA system in five key linear distance measurements,including Sn-N(surface distance),N-N(Euclidean distance),N-IMF(surface distance),N-M(surface distance)and BW(Euclidean distance).The correlation coefficients were 0.888,0.980,0.903,0.890 and 0.849,respectively(P<0.05),R2 was between 0.823?0.969.The mean differences were-0.44cm,0.16cm,-0.32cm,-0.01cm and 0.61cm,respectively.The 95%confidence intervals were(-1.96-1.07)cm,(-0.75-1.08)cm,(-1.57?0.94)cm,(-1.06?1.04)cm and(-2.23?1.02)cm,respectively,and the scattered points in the Bland-Altman plot mostly fell within the 95%confidence interval.2.A total of 22 participants were enrolled with an average age of 32.96 years,and BMI was between 18.07 and 31.89 kg/m2.Correlation coefficient,linear regression analysis and Bland-Altman plot were used to evaluate the correlation and consistency between INOVA system and JR system in multiple key linear distance measurements,including Sn-N(Euclidean distance),N-N(Euclidean distance),N-IMF(Euclidean distance),N-M(Euclidean distance),BW(Euclidean distance),Sn-N(surface distance),N-M(surface distance)and N-IMF(surface distance).The correlation coefficients were 0.916,0.992,0.956,0.955,0.967,0.893,0.952 and 0.946,respectively(P<0.05),R2 was between 0.797 and 0.984.The mean differences were 1.95mm,0.52mm,-0.93mm,0.19mm,-0.57mm,2.26mm,0.39mm and 0.25mm,respectively.The 95%consistency intervals were(-9.79?13.69)mm,(-7.10?8.14)mm,(-7.63?5.78)mm,(-7.89?8.26)mm,(-14.26?13.13)mm,(-11.35?15.87)mm,and(-7.38?8.16)m,respectively,and the scattered points in the Bland-Altman plot mostly fell within the 95%confidence interval.The results of 3D deviation analysis showed that the maximum RMSE was 5.16mm,the minimum RMSE was 1.01mm and the mean RMSE was 2.53mm(SD,1.05mm)between the two systems.3.A total of 35 participants were enrolled with an average age of 33.83 years,and BMI was between 17.51 and 31.89 kg/m2.The results of 3D deviation analysis between two different breast 3D images showed that the mean RMSE between the 3D images under eupnea was 1.73mm(SD,1.00mm),with a 95%confidence interval of(1.40?2.06)mm.The mean RMSE between the 3D images under eupnea and natural end-expiratory was 2.47mm(SD,1.27 mm)and the 95%confidence interval was(2.05?2.89)mm.The mean RMSE between the 3D images under eupnea and natural end-inspiratory was 3.77mm(SD,1.15mm)and the 95%confidence interval was(3.38?4.14)mm.The mean RMSE between the 3D images under natural end-expiratory and natural end-inspiratory was 3.80mm(SD,1.37mm),with a 95%confidence interval of(3.34-4.25)mm.By paired t test,the results showed that the mean RMSE between the 3D images under eupnea was the minimum RMSE,followed by 2.47 mm,and there was no statistical difference between 3.77mm and 3.80mm(P=0.865).The correlation coefficients were 0.958,0.991,0.970,0.973,0.928,0.948,0.970 and 0.971,respectively,and all correlation coefficients were higher than 0.9,indicating a high degree of consistency between these linear measurements of 3D breast images obtained under eupnea.4.A total of 60 patients were enrolled,31 in the control group and 29 in the study group.There were no statistical differences between the two groups in terms of age,BMI,clinical course of disease,operative time,bilateral soft tissue total resection,blood loss,drainage time and postoperative hospitalization time.No major complications occurred in either group.Two delayed wound healing occurred in each group.No other minor complication was observed.The bilateral breast volume difference of the study group was significantly smaller than the control group(39.1 vs.113.3cc,P=0.001),as well as the difference in nipple to inframammary-fold distance(2.79 vs.7.43mm,P=0.01).The observer-reported results showed that reduction mammaplasty significantly improved postoperative symmetry in all five aspects compared with preoperative symmetry in the study group(P<0.05).Furthermore,postoperative symmetrical ratings of all five aspects in the study group were statistically better than the control group(P<0.05).Conclusions1.There was a significant correlation and good consistency between the direct anthropometric method and INOVA system in the measurements of several key linear parameters.It was considered that INOVA system had good accuracy and reliability.2.There was a significant correlation and good consistency between INOVA system and JR system in the measurements of several key linear parameters,suggesting that INOVA system had good accuracy and reliability.The mean RMSE between the two systems was small,and it showed that the 3D scanning images obtained by INOVA system and JR system were comparable,that is,the data obtained by the two systems could be interoperable.3.Respiratory movements had little effect on breast 3D imaging of INOVA system,and consistent breathing state could reduce the deviation between 3D breast images.Meanwhile,INOVA system had good test-retest reliability in 3D breast imaging under eupnea.4.Three-dimensional scanning has good feasibility and effectiveness in intraoperative symmetrical assessment in reduction mammaplasty.It was confirmed that this objective approach could reduce errors of surgeons' subjective evaluation and assist symmetry adjustments,resulting in better postoperative breast symmetry in reduction mammoplasty.