Renal Surgery

With growing experience, the repertoire of laparoscopic surgery for renal cell carcinoma has been cautiously expanded to select patients undergoing laparoscopic radical nephrec-tomy for locally invasive tumor, as well as for patients undergoing complex laparoscopic partial nephrectomy (13). Current experience has already confirmed the essential benefits of intraoperative laparoscopic ultrasonography during these difficult laparoscopic surgeries for renal cell carcinoma. Laparoscopic ultrasonography is now integral to our more technically advanced renal cancer cases.

Desai et al. reported their experience with laparoscopic radical nephrectomy in the presence of renal vein thrombus. Laparoscopic ultrasonography with color Doppler imaging was felt to be an essential intraoperative tool in patients suspected of having renal vein thrombus involvement, because it provides confident identification of the proximal extent of the tumor thrombus (14).

With the placement of the laparoscopic ultrasonography probe directly on the vena cava and renal vein, tumor-bearing and tumor-free areas in the proximal renal vein could be easily identified, despite the lack of tactile sensation (14,15).

Laparoscopic ultrasonography with Doppler imaging showed the uninvolved proximal segment of the renal vein with evidence of retrograde turbulent flow from the vena cava without any intraluminal mass, even after control of the renal artery.

In patients undergoing nephron-sparing surgery for tumor, intraoperative laparoscopic ultrasonography is used to precisely delineate tumor size, depth of intraparenchymal extension, distance from the collecting system, and to evaluate for any unsuspected satellite renal masses. Such information gives the surgeon an excellent three-dimensional concept about planning the line of parenchymal incision vis-à-vis the deep margin of the tumor.

Intraoperative ultrasound provides excellent real-time visualization of the edge of the evolving ice ball, which itself is anechoic. This leading edge is clearly identified as a hyperechoic rim at the interface between frozen and unfrozen normal renal tissue.

By contact scanning from the renal surface opposite to the tumor, the deepest margin of the tumor is visualized; real-time visualization of obliteration of the deep margin of the tumor by the enlarging hyperechoic rim of the growing ice ball is one of the intraoperative parameters determining adequacy of cryoablation.

It is essential to recognize that real-time ultrasound monitoring of the evolving radio lesion is unreliable and inaccurate.

In patients undergoing nephron-sparing surgery for tumor, intraoperative laparoscopic ultrasonography is used to precisely delineate tumor size, depth of intraparenchymal extension, distance from the collecting system, and to evaluate for any unsuspected satellite renal masses (16). Such information gives the surgeon an excellent three-dimensional concept about planning the line of parenchymal incision vis-à-vis the deep margin of the tumor.

A proposed line of parenchymal incision is scored circumferentially around the tumor under laparoscopic ultrasonography guidance, maintaining an adequate margin of normal parenchyma. Steinberg et al. reported their experience in three complicated cases involving kidneys with concomitant main renal artery disease, wherein laparo-scopic ultrasonography contributed to precise localization of the renal artery stenosis, aneurysm, and stent, thereby preventing injury during hilar clamping (17).

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