**9. Specific aspects of renal cancer surgery focused upon in AR development**

There are a few aspects of renal cancer surgery (highlighted by Detmer et al. [27]), that AR development has specifically focused on. These include precise tumour resection and safe selective arterial clamping.

We have covered the issue of a precise tumour resection to preserve maximum healthy tissue throughout the chapter. However, Detmer et al. specifically mention some studies to tackle this very area. Ukimara and Gill [38] describe using different colours to signify increasing distance from the tumour and this is overlaid on the AR field of view. Another method uses contouring of the organ around the tumour margin to highlight the tumour itself. Uncertainty of the tumour margin has also been encoded by using different colours to signify certain and uncertain areas of the margin [27].

Renal artery clamping is a crucial procedural step as ischemia needs to be limited to tumourspecific parenchyma. This is done by identifying and clamping only the tumour specific arterial branches (usually tertiary or higher-order). This concept has been described as "zeroischaemia" [39]. There have been some studies detecting renal vessels underneath the organ surface and several studies aiming to identify arterial branches for selective clamping with variable success. These have been used for pre-operative planning and some intraoperative guidance. Development has been mostly based in manual registration techniques with displays over the laparoscopic view or on a separate screen [27].
