Novel backloading ureteroscopic biopsy forceps allow physicians to obtain larger specimens of upper tract lesions.
During the endosocopic diagnosis of suspicious ureteral lesions, obtaining adequate biopsy specimens is often difficult, as even the most modern ureteroscopes allow for the use of very small biopsy instruments (3F maximal size). Because pathologic diagnosis has significant implications for the need for further treatment of these lesions, innovation in the ability to obtain biopsies of greater size would be a welcome addition to the field.
To this end, the Dartmouth researchers evaluated the BIGopsy forceps and their ability to obtain biopsies of the ureter. In an ex vivo model, the forceps have been shown to obtain biopsy specimens superior to those obtained with traditional 3F forceps.
In a study presented at the 2010 World Congress of Endourology and SWL in Chicago, he and colleagues retrospectively reviewed the results of 13 patients undergoing 16 procedures. Ten patients underwent biopsy using Piranha forceps (Boston Scientific, Natick, MA) and six underwent biopsy using the BIGopsy forceps.
In addition, one patient underwent holmium laser for lesion excision and four patients underwent en bloc excision using a ureteroscopic basket. Specimen size, subjective biopsy quality, and ultimate pathologic diagnosis were assessed from each biopsy.
Mean size of the biopsied lesions (mm±SD) was 1.1±0.3 in the Piranha group, 2.9±1.6 in the BIGopsy group, 5.4±3.7 in the basket group, and 7.5±3.5 in the laser group. Of the five patients who underwent biopsies with both BIGopsy and Piranha forceps, the BIGopsy specimens were a mean 1.8 mm larger in size. There were four cases in which a definitive diagnosis could not be made with the Piranha forceps but was made with the BIGopsy forceps. The BIGopsy forceps correctly established a diagnosis of high-grade urothelial carcinoma, low-grade urothelial carcinoma, carcinoma in situ, and pyelitis cystica.
The authors made an interesting distinction between biopsies of tumors on stalks versus sessile tumors, observing that tumors on stalks are excised and biopsied effectively using the laser or basket techniques, while more sessile tumors and flat mucosal lesions require the use of forceps. It is this more sessile type of lesion, the authors note, that is biopsied with superior results using the BIGopsy forceps.
Technical considerations in using backloading forceps must be considered. When asked about the possibility of compromised vision using the device, Dr. Pais noted, "Care must be taken to assure that inadvertent injury to the ureter does not occur. Ureteral access sheaths were routinely used in this study," he added.
The authors concluded that the BIGopsy forceps allow for removal of ureteral and renal pelvic tissue significantly larger than with the standard 3F ureteroscopic biopsy forceps. This difference in size appears to yield a higher likelihood of arriving at the correct diagnosis when obtaining biopsies.
While this study is limited by sample size, it provides promising early evidence that the BIGopsy will prove to be a useful tool in the diagnosis and management of suspicious ureteral lesions.