**4.4 Inertial unit measurement system**

In the last few years, introduction and use of inertial sensors in the analysis and characterization of posture variability in the context of minimally invasive surgery has been a great advance in biomechanics methodology, as 3D photogrammetry requires a lot of time for digitation of images. This has been the most important reason for BioẼrgon Research group to record and analyze laparoscopic procedures in 3D using this technology, being a pioneer and probably the only one group to use it. Undoubtedly, this is much more an efficient instrumental technique for the characterization of posture in minimally invasive surgery [34]. In this sense, a study using the commercial system XSens MVN Biomech (**Figure 19**) was carried out in the Jesus Usón Minimal Invasive Surgery Center. Eight surgeons participated in the study (four novices and four experts) and performed 24 simple sutures with conventional instruments. The results obtained regarding the position of the surgeons corroborate the high variability found in the studies carried out with 3D photogrammetry. The values found show CV greater than 70% in all joints and especially in the wrist joint flexion-extension and radial and ulnar deviation (**Figure 20**).

**Figure 20.** *Results from capture of surgeons' posture performing a simple suture.*
