1 General Surgery Unit, Department of Surgery, Translational and New Technologies in Medicine, University of Pisa, Pisa, Italy. gregoriodifranco@gmail.com.
2 General Surgery Unit, Department of Surgery, Translational and New Technologies in Medicine, University of Pisa, Pisa, Italy.
3 EndoCAS (Center for Computer Assisted Surgery), University of Pisa, Pisa, Italy.