SWL generally is considered to be the first-line therapeutic option for most renal stones < 2 cm [7, 8]. SWL outcome are influenced by stone composition, the lower calyceal angle that permits the clearance of the resultant residuals, and the patient’s body habits, which may decrease the efficacy of SWL and increase the re-treatment rate [9].
In the present study, Chinese minimally invasive (MIPNL) is defined as a PNL technique with small working sheath, which is performed using an 8–9.8 Fr URS through a 16 Fr percutaneous renal access tract, this is technique was used also by other [10, 11].
In our study, the overall stone-free rate (SFR) after MIPNL was (82%). This result are comparable to results published by Li et al. [12] Huang et al. [10], and Giusti et al. [13] who reported the SFR of 83.9%, 85.4%, and 77.5%, respectively.
The only reported major intraoperative complication is the bleeding in one patient 1.5%, that needed blood transfusion; these results are less than to those reported by Huang et al. [10], who reported bleeding in four patients (9.8%) with only one patient (2.4%) requiring blood transfusion.
Pelvicalyceal perforation was reported in three patients (4.5%). Zhong et al. [10] reported pelvic perforation in two patients (6.9%), and on the other hand, Hung et al. [14] and Knoll et al. [15] reported no pelvic perforation in any of patients during MIPNL procedure.
Leakage and fever were the most common postoperative complications in five patients (7.5%) and six patients (20%), respectively. Hung et al. [10] reported leakage in two patients (4.9%) and fever in five patients (12.1%), and Lu et al. [11] reported leakage in 3.1% and fever in 15.6% post-MIPNL.
The use of auxiliary procedures such as SWL, RIRS, and second PNL may be necessary to achieve high SFR. The possibility of needing such auxiliary procedure to achieve a satisfactory outcome should be explained to the patients.
In our study, because of 12 (18%) patients with failed MIPNL, second MIPNL was performed in 3 (4.5%) cases, SWL in 7 (10%), and RIRS in 2 (3%) cases. De Le et al. [16], Hung et al. [10], and Monga et al. [17] reported auxiliary procedure post-MIPNL in 21.4%, 14.6%, and 9.5%, respectively.
The body mass index of our patients did not make a significant difference nor need special modifications in our tools in order to complete our procedure. Sometimes only, it consumes more time in positioning and more effort for successful puncture in such patients with high BMI.
The learning curve of a single surgeon suggests that competence at performing classic PNL is an important step to make learning curve of this technique better and faster. However, it needs some more time than classic PNL due to difficulties related to vision, diminished irrigation, and limited field.
We named some limitations in our study. Firstly, this was a study about a small group of patients. Secondly, it was the early experience of our center in practicing this technique. Thirdly, there is need for comparison with other procedures like RIRS.
There were some difficulties that faced us and caused decreased SFR, the diminished intraoperative field visibility (especially when patient had bleeding), the need for fragmentation into very small stones suitable for ureteroscopic graspers and/or baskets, and the small sheath.