The C.L.A.M.P. Nephrometry score: A system for preoperative assessment of laparoscopic partial nephrectomy with Segmental Renal Artery Clamping

Laparoscopic partial nephrectomy with segmental renal artery clamping is associated with a less warm ischemic injury and better postoperative affected renal function compared with main renal artery clamping. However, its indication remains unclear. We established a standardized nephrometry scoring system (The C.L.A.M.P. Nephrometry Score) to evaluate its flexibility in preoperative assessment. This scoring system based on 5 components. The ranking (C)oefficient of each score and the (L)ocation of the clamping position of the target artery and areas of the target artery entering the renal sinus: (A)nterior boundary, (M)ulti-boundary and (P)osterior boundary. We applied this system to analyze data from 106 consecutive patients who underwent SRAC during LPN and divided these patients into 3 groups based on their C.L.A.M.P. scores. The rate of conversion to main renal artery clamping and clamping success rate and the affected side GFR reduction showed significant differences among the groups (P < 0.001). However, parameters such as blood loss, Warm ischemia time and postoperative hospitalization were not significantly different. The C.L.A.M.P. nephrometry score shows strong ability in distinguishing different complexities of artery characteristics and plays a promising role in identifying patients who are suitable for the SRAC technique.