The feasibility of real-time bladder mapping using a stereotactic navigational system

Stereotactic navigational devices have been implemented in neurosurgery, orthopedics and ear-nose-throat to improve surgical accuracy. However, the feasibility of navigating inside the bladder has not yet been investigated. Occasionally, transurethral resections of bladder tumors (TURBTs) are impeded by bleeding and cloudiness inside the bladder and, consequently, the bladder lesions are not found back easily. In addition, small bladder lesions are often concealed when viewed with the camera some distance away from the bladder wall due to low contrast differences. The aim of the study is to investigate the feasibility of real-time bladder mapping using the Medtronic Stealthstation system, without the use of pre-operative images. Seven patients scheduled for a TURBT were included in the study. During the TURBT procedure, the spatial coordinates of the bladder lesions were recorded two times independently, after filling the bladder with a fixed volume of 390 ml. The distance between the spatial coordinates of two consecutive measurements, in millimeters, was calculated. We found that bladder lesions can be found back using the navigational system with an accuracy of less than 12 mm. Real-time bladder navigation is feasible without the necessity of pre-operative images or calibration. If the coordinates are directly superimposed on the video image this could facilitate the retrieval of bladder lesions during TURBT. This system could reduce the stress for the surgeon and decrease the operating time.