Characterization of strain microgauges for the monitoring of the deformations of a medical needle during its insertion in human tissues

Further to the first fabrication of strain microgauges on cylindrical metal substrates (Yang et al. Microelectron Eng 97:285–288, 2012), that we cannot experiment because of problems of wire bonding, we have reviewed the bonding process. These microgauges enable the real-time measurement of the medical needle strain distribution from which its deflection status can be deduced. So this paper deals with the new bonding process of the microgauges and the detailed experimentations. These experimentations consist in constrain the needle and verify that we can measure the strain. They allow also the calculations and the comparison of the theoretical and experimental gauge factor. Finally we discuss about the improvement of the prototype in terms of optimization of the process. Finally some material questions must find solution.