Joris van Dongen

206 Chapter 9 Cutometer MPA850 R7 output parameter (the ratio of elastic recovery to the total deformation, elaborated by the R5 (the net elasticity) and R6 (the ratio of viscoelastic to elastic extension) parameters. Volumetric changes of the nasolabial fold Standardized photographs were captured in three views with a professional 3D camera system (AP, 3Q left and right) at every follow-upmoment. Primarily, 3D reconstructions were used to determine volumetric facial changes over time, but were abandoned due to data inconsistency, variation and reproducibility of the measured area. Instead, the pre-operative, 3 months and 1 year post-operative AP-views were used to determine changes in the nasolabial fold depth using a validated grading method (Merz Scale) 17-20 , that consists of five options (I=minimal fold expression to V=most prominent fold expression) In total, four independent plastic surgeons served as expert panel. The nasolabial fold was chosen because alteration in depth would implicate relevant external changes of facial appearance. Patient reported recovery time and satisfaction Recovery after the procedure was assessed bymeans of two patient questionnaires send at 2 and 4 weeks after the operation. Questions included the number of days required to return to work and or resume social activities without using camouflaging agents, and notable changes in facial volume and skin expressed on a visual analogue scale (VAS 1: no changes -10: most significant changes). Patient reported satisfaction was recorded by means of a questionnaire send 6 months after surgery: questions included overall satisfaction, changes in volume effect, skin changes andwhether or not theywould recommend the procedure to a peer (VAS 1-10). Statistical analysis Statistical analyses were performed by an independent statistician that received all blinded data by the principal investigator, along with the original randomization from the surgeon. All analyses were done using SPSS 20 (IBM, Chicago, IL, USA). Data Fig.s were generated using Prism 6 (GraphPad Software, La Jolla, CA, USA). The paired samples t-test, ANOVA analysis of covariance and standard linear regression were used. All data fulfilled the requirements for normality and equal variances. A two-sided p<0·05 was considered statistically significant.