Histological evaluation of cold versus hot cutting: clinical impact on margin status for laparoscopic partial nephrectomy.

PURPOSE

While most laparoscopic nephron sparing surgery is performed using cold scissors, energy based devices may also be used. A criticism of this approach has been the potential thermal destruction of the cellular architecture at the tumor margin, precluding the ability to accurately determine whether tumor cells are present. We clinically characterized the histological appearance of tumor margins excised with cold scissors, and bipolar and ultrasonic shears.

MATERIALS AND METHODS

We evaluated 40 renal mass excisions performed by a total of 3 urologists at our institution between February 2003 and March 2007. There were 10 bipolar (5 mm LigaSure), 20 ultrasonic (Harmonic Scalpel) and 10 cold excisions. All slides were randomly evaluated twice by a single pathologist blinded to surgeon and excision method. Histological interpretation of the margin was scored as clear vs indeterminate. Variables, including margin fragmentation, artifact, extravascular blood clot, parenchymal hemorrhage, capillary congestion and vessel sealing, were assessed and scored on a scale of 0 to 3, that is 0--none, 1-1% to 25%, 2-26% to 50% and 3--greater than 50%.

RESULTS

The pathologist was able to confidently identify cells at the margin as being malignant or benign in all cases. Histologically the ultrasonic scalpel demonstrated increased fragmentation and extravascular blood clotting compared with those of the other cutting methods (p <0.025 and <0.026, respectively). The ultrasonic scalpel also showed increased artifact depth compared to that of cold cutting (p <0.001). There were no statistical differences between the groups regarding margin artifact, parenchymal hemorrhage or capillary congestion. No statistical significance was observed in any variables between bipolar and cold cutting.

CONCLUSIONS

Despite some degree of cellular damage the ability to determine whether cells at the margin were benign or malignant was not affected by using an energy based bipolar or ultrasonic device.