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.
Photodynamic diagnosis (PDD) is a technique that enhances the detection of tumors during cystoscopy using a
photosensitizer which accumulates primarily in cancerous cells and will fluoresce when illuminated by violetblue
light. A disadvantage of PDD is the relatively low specificity. In this retrospective study we aimed to
identify predictors for false positive findings in PDD. Factors such as gender, age, recent transurethral resection
of bladder tumors (TURBT), previous intravesical therapy (IVT) and urinary tract infections (UTIs) were
examined for association with the false positive rates in a multivariate analysis. Data of 366 procedures and 200
patients were collected. Patients were instilled with 5-aminolevulinic acid (5-ALA) intravesically and 1253
biopsies were taken from tumors and suspicious lesions. Female gender and TURBT are independent predictors
of false positives in PDD. However, previous intravesical therapy with Bacille Calmette-Guérin is also an
important predictor of false positives. The false positive rate decreases during the first 9-12 weeks after the latest
TURBT and the latest intravesical chemotherapy. Although shortly after IVT and TURBT false positives
increase, PDD improves the diagnostic sensitivity and results in more adequate treatment strategies in a
significant number of patients.
Raman spectroscopy is an optical technique that can be used to obtain specific molecular information of biological tissues. It has been used successfully to differentiate normal and pre-malignant tissue in many organs. The goal of this study is to determine the possibility to distinguish normal tissue from bladder cancer using this system.
The endoscopic Raman system consists of a 6 Fr endoscopic probe connected to a 785nm diode laser and a spectral recording system. A total of 107 tissue samples were obtained from 54 patients with known bladder cancer during transurethral tumor resection. Immediately after surgical removal the samples were placed under the Raman probe and spectra were collected and stored for further analysis. The collected spectra were analyzed using multivariate statistical methods.
In total 2949 Raman spectra were recorded ex vivo from cold cup biopsy samples with 2 seconds integration time. A multivariate algorithm allowed differentiation of normal and malignant tissue with a sensitivity and specificity of 78,5% and 78,9% respectively.
The results show the possibility of discerning normal from malignant bladder tissue by means of Raman spectroscopy using a small fiber based system. Despite the low number of samples the results indicate that it might be possible to use this technique to grade identified bladder wall lesions during endoscopy.