To explore the application of the renal calculus 3D model based on CT in percutameous nephrolithotomg (PCNL).

From July 2016 to September 2016, twelve patients were diagnosed with renal calculus and underwent PCNL in Shenzhen Baoan District People's Hospital. The mean age was 39 (range: 28-46) years old. Among them, there were 5 patients with left renal calculus and 7 patients with right renal calculus. The maximum diameter of the renal calculus was between 2.3 to 4.2 cm, and the mean diameter was 3.2 cm according to the CT scan. The CT image data collected from these patients would be divided and rebuilt its 3D model by using the 3D rebuilding software MIMICS 17.0, to build a personalized 3D model of the renal calculus. Before the surgery, 4 surgeons would design a specific surgery strategy according to the 3D model of the renal calculus and combine it with the iconography materials. During the surgery, they would record the practical operating data, and fill the appraisal questionnaire of the 3D models after the surgery to appraise the availability of the 3D model. As for the patients and their families, the 3D renal calculus model was used as a tool for communication before the surgery, and they were invited to fill the appraisal questionnaire.

The 3D renal calculus models of these 12 patients were successfully constructed. The models clearly showed the size and location of the renal calculus, the inner renal collecting system, renal pelvis, vein and the interrelationship with the adjacent anatomical structures. The virtual puncture point and the renal calyx of puncture were basically corresponded to the actual operation. The puncture depth of virtual operations was (6.6±0.8) cm, while the puncture depth of actual operations was (7.1±0.7) cm, and there was no significant difference (P>0.05). The mean evaluation score of the models given by surgeons was (8.5±0.6). And the mean score of the doctor-patient conversation before operation given by the patients or their family members was (8.4±0.7).

The 3D renal calculus models based on CT can clearly reflect not only the size and location of renal calculus, but also the relationship between the kidney and adjacent anatomical structures.The models also play a very important role in preoperative planning and operative process. Meanwhile, the models could be useful in the doctor-patient consultation.