Meccanica (2013) 48:145–158 DOI 10.1007/s11012-012-9590-x Orientation module for surgical instruments—a systematical approach C. Vaida · N. Plitea · D. Pisla · B. Gherman Received: 29 May 2011 / Accepted: 31 July 2012 / Published online: 14 August 2012 © Springer Science+Business Media B.V. 2012 Abstract The design and analysis of a new module for the orientation of the instrument tip in minimally invasive surgery are presented in the paper. The as- pects related to its design and modularity point out the advantages of the proposed solution: increased ergonomics and dexterity, wider workspace, reduced number of incisions. The solution is analysed with respect to the main drawbacks which are currently reported regarding the use of flexible instruments in minimally invasive procedures. A comparative study is performed analysing the workspace of classical in- struments and the ones that use the orientation mod- ule in order to assess the possible benefits of the proposed solution. The same approach evaluates the behaviour and possible advantages of robotic surgical instruments equipped with such an orientation mod- ule. Keywords Modular design · Workspace analysis · Dexterous instruments · Robotic surgery C. Vaida · N. Plitea · D. Pisla ( ) · B. Gherman CESTER Research Centre, Department of Mechanics and Computer Programming, Technical University of Cluj-Napoca, Cluj-Napoca, Romania e-mail: Doina.Pisla@mep.utcluj.ro C. Vaida e-mail: Calin.Vaida@mep.utcluj.ro 1 Introduction “Coninuetur remedia”—Let the medicine be contin- ued. Medicine, and especially its invasive branch, surgery, has known a continuous evolution animated by the ultimate goal of improving the life quality of humankind. In surgery, the latest revolution began 25 years ago, when appeared the concept of mini- mally invasive surgery (MIS) for the first time. Since then, it has progressed reaching the present stage of robotic assisted minimally invasive procedures adding the newer NOTES (Natural Orifice Transluminal En- doscopic Surgery) and SILS (Single-Incision Laparo- scopic Surgery). While the real benefits of NOTES are somehow doubtful, as shown in [1] and [2], SILS already represents a real benefit for patients suitable for this procedure. Compared to classical or MIS pro- cedures the benefits for patients are: decreased pain, even shorter recovery period (counted in hours), lower morbidity, reduced cost and superior cosmesis. Kam- ran, Patel and others [2] published a review where they analysed several hundreds of cases before pointing out these advantages. However, SILS as the name sug- gests, means the introduction of all the surgical tools (camera and instruments) through a narrow port of 15– 20 mm, or the use of multilumen trocar forcing the surgeon to work in awkward positions, with crossing instruments, etc. These challenges, which the surgeon faces in SILS [3], encourage further researches for in- novative flexible instruments solutions aiming to im- prove the safety and ergonomics of the procedures.