Preoperative simulation of partial nephrectomy with three-dimensional computed tomography.

OBJECTIVE

To evaluate prospectively the accuracy of computer-aided three-dimensional (3D) volume-rendered computed tomography (CT) in determining the appropriate anatomical limits (tumour size, tumour location, multifocality and vascular supply) and as a potential tool in the preoperative simulation of nephron-sparing surgery (NSS) in patients with small-volume renal cell carcinoma (RCC).

PATIENTS AND METHODS

The study included 36 patients who underwent transperitoneal radical nephrectomy for RCC of < 4 cm diameter. Helical CT was undertaken before surgery and the extent of the tumour, the course of major renal arteries and veins, and the relationship of the tumour to the collecting system were shown by 3D volume-rendered CT. The CT findings were compared with the pathological results of all kidney specimens, obtained using 3-mm step-sections.

RESULTS

Before nephrectomy, 39 renal tumours were identified in the 36 patients; three renal lesions of < 4 mm were not detected. All main venous branches and 42 of 43 arteries were identified by 3D volume-rendered CT. Knowing these features, a partial nephrectomy was simulated; a surgical lesion to the pelvicalyceal or vascular system which would have been produced by the simulated surgery was displayed in colour on the simulated surface of the section.

CONCLUSION

Computer simulation provided an excellent 3D reconstruction of all kidneys, including the tumour, vasculature and renal hilum, allowing a significantly better preoperative evaluation of the renal mass. Visualizing possible resection margins and predicting the operative risks seem to be major advantages of this new method, especially when preparing for complex surgery. Reconstructed 3D CT appears to be a useful tool for defining the indications for and limitations of NSS.