Super-mimi Percutaneous Nephrolithotomy(SMP) For The Treatment Of Renal Calculi Larger Than 2cm

Background and ObjectivePercutaneous nephrolithotomy(PCNL)has become the gold standard for the treatment of large and complex upper urinary tract stones after more than half a century of development.With the continuous improvement of technology and the accumulation of surgical experience,as well as the concept of minimally invasive deep-rooted popularity,the traditional PCNL has begun to move in a more minimally invasive direction.The development of various types of minimally invasive PCNL makes the treatment of urinary stones become more diverse.In order to achieve the best surgical results,clinicians continue to explore and think about the advantages and disadvantages of different surgical methods.However,in the past,minimally invasive PCNL has made narrower improvements on the basis of the original channel in order to pursue less blood loss and kidney damage.The narrowing of the passage meant that the requirements for irrigation,suction,and lithotripsy could not be met at the same time.In addition,the restriction of the equipment at the time led to the fact that the surgical method could only meet the requirements of smashing the stone and could not achieve the purpose of clearing the stone.Prof.Zeng Guohua developed a micro-channel percutaneous nephroscope with an outer diameter of only 7F for the advantages and disadvantages of various minimally-invasive PCNLs.Because of the corresponding vacuum suction device,he was able to complete the task of clear stone at the same time as smashing stone.This new technique was called super-mini percutaneous nephrolithotomy(SMP).Although the initial purpose was to provide extra treatment for Extracorporeal Shock Wave Lithotripsy(ESWL)and Retrograde Intrarenal Surgery(RIRS),and to treat kidney stones whose size is mainly below 2cm.However,with the continuous improvement of technology and improvement of equipment,especially the emergence of high-power holmium laser,the efficiency of crushed stone has been greatly improved,and the scope of indications of SMP has gradually expanded.Studies have shown that SMP treatment can achieve satisfactory results for large volumes of kidney stones.So,this study summarized the surgical experience and clinical results of the use of SMP in the treatment of renal calculi with larger than 2cm in our department,to investigate the safety and efficacy of SMP in the treatment of larger than 2 cm renal stones.Materials and methodsClinical data of patients with renal calculi treated with SMP from Department of Urology,Second Affiliated Hospital of Zhengzhou University from December 2016 to January 2018 were collected.The basic datas including age,sex,diameter and CT value of stones,complications and surgical history were collected and analyzed.The outcomes dates including success rate of primary surgery,postoperative rate of stone free(SFR)after one day,postoperative hemoglobin decrease,Postoperative serum creatinine value,catheterization,Postoperative fever were also counted.The form of mean ± standard deviation was used for the measurement data,and results retain 2 decimal places.ResultsIn this study,a total of 22 patients were collected and all patients underwent single-channel super-mini percutaneous nephrolithotomy(SMP),of which 15 males and 7 females.Left kidney stones in 13 cases,right kidney stones in 9 cases.There were 3 cases of middle kidney calyx stones,10 cases of lower kidney calyx stones,6 cases of renal pelvis stones,2 cases of lower kidney calyx and stones renal pelvis stones,1 case of diverticulum stones.The maximum diameter of stone is 21~36mm,average(25.5±5.39)mm.The CT values of stones ranged from 591 to 1633 HU,with an average of(1001.46±279.29)HU.All the 22 cases were successfully performed single-channel surgery,and the success rate was 100%.The drop of hemoglobin is 3-31g/L with an average of(13.82±8.92)g/L.One patient had preoperative serum creatinine of 120 ?mol/L and postoperative serum creatinine of 119 ?mol/L.The remaining patients had normal serum creatinine before and after surgery.The results of 24 h postoperative review of KUB and ultrasound showed that 14 patients cleared stones and the SFR was 63.64% at 1 day after operation.8 cases had residual stones,5 cases were assisted with external Physical vibration lithecbole,2 cases were assisted with extracorporeal shock wave lithotripsy,and 1 case was rejected with auxiliary procedure.After 1 month of follow-up CT,the total SFR was 86.36%(19/22).9 cases of preoperative urine showed leukocytes positive,of which 2 cases of preoperative urine culture were Enterococcus faecalis and Candida albicans respectively.2 cases of postoperative fever with antibiotics and physical cooling treatment returned to normal,and one case of bleeding after external Physical vibration lithecbole and blood transfusion was given.Except for one patient with bleeding,the length of hospital stay was longer for 16 days,and the rest of patients were hospitalized for 3-7 days,with an average of(4.19±1.33)days.Postoperatively,only 2 cases of renal fistulas were indwelled.Only 2 cases of double J were indwelled.Only 6 cases of ureteral catheters were indwelled.F5 ureteral catheters and renal fistulas were left in 7 cases at the same time.Double J and renal fistulas were left in 3 cases at the same time.2 cases were completely tubeless.ConclusionsSMP is a safe and effective surgical method.It can be used as an alternative when treating kidney stones larger than 2cm.