Tag Archive for: super-mini percutaneous nephrolithotomy

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Article of the week: Management of large renal stones with super‐mini percutaneous nephrolithotomy: an international multicentre comparative study

Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

There is also a visual abstract created by Cora Griffin from King’s College London.

If you only have time to read one article this week, we recommend this one. 

Management of large renal stones with super-mini percutaneous nephrolithotomy: an international multicentre comparative study

Yang Liu*, Chao Cai*, Albert Aquino, Shabir Al-Mousawi, Xuepei Zhang§, Simon K.S. Choong, Xiang He**, Xianming Fan††, Bin Chen‡‡, Jianhua Feng§§, Xuhui Zhu¶¶, Abdulla Al-Naimi***, Houping Mao†††, Huilong Tang‡‡‡, Dayong Jin§§§, Xiancheng Li¶¶¶, Fenghong Cao****, Hua Jiang††††, Yongfu Long‡‡‡‡, Wei Zhang§§§§, Gang Wang¶¶¶¶, Zihao Xu*, Xin Zhang*, Shanfeng Yin* and Guohua Zeng*

*Department of Urology, Guangdong Key Laboratory of Urology, Minimally Invasive Surgery Center, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China, Department of Urology, Jose R. Reyes Memorial Medical Center, Manila, Philippines, Division of Urology, SABAH ALAHMAD Urology Center, Ministry of Health, Al-Amiri Hospital, Kuwait City, Kuwait, §Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China, Institute of Urology, University College London Hospitals, London, UK, **Department of Urology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, ††Department of Urology, The Third Affiliated Hospital of Xiamen, The Third Affiliated Hospital of Fujian University of Traditional Chinese Medicine, ‡‡Department of Urology, The Affiliated Hospital of Xiamen University, Xiamen, §§Department of Urology, Longgang District Central Hospital, Shenzhen, ¶¶Department of Urology, Beijing Chaoyang Hospital, Affiliated to Capital Medical University, Beijing, China, ***Department of Urology, Hamad Medical Corporation, Doha, Qatar, †††Department of Urology, First Affiliated Hospital of Fujian Medical University, Fuzhou, ‡‡‡Department of Urology, The First Hospital of Hunan University of Traditional Chinese Medicine, Changsha, §§§Department of Urology, Liaoyuan City Central Hospital, Liaoyuan, ¶¶¶Department of Urology, Second Affiliated Hospital of Dalian Medical University, Dalian, ****Department of Urology, North China University of Science and Technology Affiliated Hospital, Tangshan, ††††Department of Urology, Zhongda Hospital Southeast Hospital, Nanjing, ‡‡‡‡Department of Urology, Central Hospital of Shaoyang, Shaoyang, §§§§Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, and ¶¶¶¶Department of Urology, National Urological Cancer Center, Institute of Urology, Peking University First Hospital, Peking University, Beijing, China

Abstract

Objectives

To comparatively evaluate the clinical outcomes of super‐mini percutaneous nephrolithotomy (SMP) and mini‐percutaneous nephrolithotomy (Miniperc) for treating urinary tract calculi of >2 cm.

Patients and Methods

An international multicentre, retrospective cohort study was conducted at 20 tertiary care hospitals across five countries (China, the Philippines, Qatar, UK, and Kuwait) between April 2016 and May 2019. SMP and Miniperc were performed in 3525 patients with renal calculi with diameters of >2 cm. The primary endpoint was the stone‐free rate (SFR). The secondary outcomes included: blood loss, operating time, postoperative pain scores, auxiliary procedures, complications, tubeless rate, and hospital stay. Propensity score matching analysis was used to balance the selection bias between the two groups.

Results

In all, 2012 and 1513 patients underwent SMP and Miniperc, respectively. After matching, 1380 patients from each group were included for further analysis. Overall, there was no significant difference in the mean operating time or SFR between the two groups. However, the hospital stay and postoperative pain score were significantly in favour of SMP (both  < 0.001). The tubeless rate was significantly higher in the SMP group (72.6% vs 57.8%,  < 0.001). Postoperative fever was much more common in the Miniperc group (12.0% vs 8.4%,  = 0.002). When the patients were further classified into three subgroups based on stones diameters (2–3, 3–4, and >4 cm). The advantages of SMP were most obvious in the 2–3 cm stone group and diminished as the size of the stone increased, with longer operating time in the latter two subgroups. Compared with Miniperc, the SFR of SMP was comparable for 3–4 cm stones, but lower for >4 cm stones. There was no statistical difference in blood transfusions and renal embolisations between the two groups.

Conclusions

Our data showed that SMP is an ideal treatment option for stones of <4 cm and is more efficacious for stones of 2–3 cm, with lesser postoperative fever, blood loss, and pain compared to Miniperc. SMP was less effective for stones of >4 cm, with a prolonged operating time.

Visual abstract: Management of large renal stones with super‐mini percutaneous nephrolithotomy

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Video: Super-mini percutaneous nephrolithotomy

Super‐mini percutaneous nephrolithotomy (SMP) vs retrograde intrarenal surgery for the treatment of 1–2 cm lower‐pole renal calculi: an international multicentre randomised controlled trial

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Abstract

Objectives

To compare the safety and effectiveness of super‐mini percutaneous nephrolithotomy (SMP) and retrograde intrarenal surgery (RIRS) for the treatment of 1–2 cm lower‐pole renal calculi (LPC).

Patients and Methods

An international multicentre, prospective, randomised, unblinded controlled study was conducted at 10 academic medical centres in China, India, and Turkey, between August 2015 and June 2017. In all, 160 consecutive patients with 1–2 cm LPC were randomised to receive SMP or RIRS. The primary endpoint was stone‐free rate (SFR). Stone‐free status was defined as no residual fragments of ≥0.3 cm on plain abdominal radiograph of the kidneys, ureters and bladder, and ultrasonography at 1‐day and on computed tomography at 3‐months after operation. Secondary endpoints included blood loss, operating time, postoperative pain scores, auxiliary procedures, complications, and hospital stay. Postoperative follow‐up was scheduled at 3 months. Analysis was by intention‐to‐treat. The trial was registered at https://clinicaltrials.gov/ (NCT02519634).

Results

The two groups had similar baseline characteristics. The mean (sd) stone diameters were comparable between the groups, at 1.50 (0.29) cm for the SMP group vs 1.43 (0.34) cm for the RIRS group (P = 0.214). SMP achieved a significantly better 1‐day and 3‐month SFR than RIRS (1‐day SFR 91.2% vs 71.2%, P = 0.001; 3‐months SFR 93.8% vs 82.5%, P = 0.028). The auxiliary procedure rate was lower in the SMP group. RIRS was found to be superior with lower haemoglobin drop and less postoperative pain. Blood transfusion was not required in either group. There was no significant difference in operating time, hospital stay, and complication rates, between the groups.

Conclusions

SMP was more effective than RIRS for treating 1–2 cm LPC in terms of a better SFR and lesser auxiliary procedure rate. The complications and hospital stay were comparable. RIRS has the advantage of less postoperative pain.

 

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Article of the Month: SMP vs retrograde intrarenal surgery for the treatment of 1–2 cm lower‐pole renal calculi: an international multicentre RCT

Every month, the Editor-in-Chief selects an Article of the Month from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation. There is also a video, provided by the authors, showing SMP.

If you only have time to read one article this week, it should be this one.

Super‐mini percutaneous nephrolithotomy (SMP) vs retrograde intrarenal surgery for the treatment of 1–2 cm lower‐pole renal calculi: an international multicentre randomised controlled trial

Guohua Zeng* , Tao Zhang* , Madhu Agrawal, Xiang He, Wei Zhang§, Kefeng Xiao, Hulin Li**, Xuedong Li††, Changbao Xu‡‡, Sixing Yang§§, Jean J. de la Rosette¶¶***, Junhong Fan*, Wei Zhu* and Kemal Sarica†††

 

Department of Urology *Minimally Invasive Surgery Center, The First Afliated Hospital of Guangzhou Medical University, **Guangdong Key Laboratory of Urology, ZhuJiang Hospital of Southern Medical University, Guangzhou, Zhejiang Provincial Peoples Hospital, Zhejiang, §The First Afliated Hospital With Nanjing Medical University, Nanjing, Shenzhen Peoples Hospital, Shenzhen, ††The Second Afliated Hospital of Harbin Medical University, Harbin, ‡‡The Second Afliated Hospital of Zhengzhou University, Zhengzhou, §§Renmin Hospital of Wuhan University, Wuhan, China, Centre for Minimally Invasive Endourology, Global Rainbow Healthcare, Agra, India, ¶¶Istanbul Medipol University, Istanbul, Turkey, ***AMC University Hospital, Amsterdam, The Netherlands, and †††Dr. Lut Kirdar Kartal Research and Training Hospital, Istanbul, Turkey

Read the full article

Abstract

Objectives

To compare the safety and effectiveness of super‐mini‐percutaneous nephrolithotomy (SMP) and retrograde intrarenal surgery (RIRS) for the treatment of 1–2 cm lower‐pole renal calculi (LPC).

Patients and Methods

An international multicentre, prospective, randomised, unblinded controlled study was conducted at 10 academic medical centres in China, India, and Turkey, between August 2015 and June 2017. In all, 160 consecutive patients with 1–2 cm LPC were randomised to receive SMP or RIRS. The primary endpoint was stone‐free rate (SFR). Stone‐free status was defined as no residual fragments of ≥0.3 cm on plain abdominal radiograph of the kidneys, ureters and bladder, and ultrasonography at 1‐day and on computed tomography at 3‐months after operation. Secondary endpoints included blood loss, operating time, postoperative pain scores, auxiliary procedures, complications, and hospital stay. Postoperative follow‐up was scheduled at 3 months. Analysis was by intention‐to‐treat. The trial was registered at https://clinicaltrials.gov/ (NCT02519634).

Results

The two groups had similar baseline characteristics. The mean (sd) stone diameters were comparable between the groups, at 1.50 (0.29) cm for the SMP group vs 1.43 (0.34) cm for the RIRS group (P = 0.214). SMP achieved a significantly better 1‐day and 3‐month SFR than RIRS (1‐day SFR 91.2% vs 71.2%, P = 0.001; 3‐months SFR 93.8% vs 82.5%, P = 0.028). The auxiliary procedure rate was lower in the SMP group. RIRS was found to be superior with lower haemoglobin drop and less postoperative pain. Blood transfusion was not required in either group. There was no significant difference in operating time, hospital stay, and complication rates, between the groups.

Conclusions

SMP was more effective than RIRS for treating 1–2 cm LPC in terms of a better SFR and lesser auxiliary procedure rate. The complications and hospital stay were comparable. RIRS has the advantage of less postoperative pain.

 

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Editorial: Ureteroscopy vs miniaturized percutaneous nephrolithotomy: what and who are we comparing?

We read with interest the article by Zeng et al. [1] comparing super‐mini percutaneous nephrolithotomy (SMP) with ureteroscopy (URS) for treatment of 1–2‐cm lower pole renal calculi. In this prospective randomized controlled trial, SMP achieved significantly higher stone‐free rates (SFRs) than URS on first‐day KUB with ultrasonography (91.2% vs 71.2%) as well as on 3‐month CT (93.8% vs 82.5%). Haemoglobin drop and pain score were higher in the SMP group, although no blood transfusions were required in either group. We congratulate the authors for this well conducted multicentre study and for the comprehensive report of their results.

A few comments are worth making to aid correct interpretation of the data presented in this study. First, it remains unclear whether the superiority of SMP over URS in terms of SFR was inherent to operating techniques, or whether this might have been the result of superior skills and interest of the surgeons favouring SMP. Surgeons were (obviously) not blinded to operating technique, which could have led to a bias. No study available in the literature has yet questioned whether a surgeon might be better at one technique (SMP or URS) than another. Ultimately, results may differ if both techniques were compared between two expert centres dedicated to each technique, respectively.

Second, the study protocol allowed surgeons to leave fragments up to 2 mm at the end of URS procedures. Strikingly, ‘stone‐free’ status was defined as residual fragments ≤3 mm. This methodology may well have affected the results, as neither endoscopy, KUB, ultrasonography nor CT is precise enough to differentiate 2‐mm from 3‐mm fragments [2, 3]. Arguably, this might have contributed to a lower SFR in the URS group.

Third, the study protocol did not clearly describe indications and choices for auxiliary procedures. Consequently, four of seven SMP (57.1%) and 19 of 23 URS patients (82.6%) with ‘clinically significant’ residual fragments were offered auxiliary procedures such as SMP, shockwave lithotripsy or external physical vibration lithecbole. Remarkably, none of the patients in the URS arm was offered any second‐look intervention, while this was the case in the SMP group.

Fourth, achievements made in one country may not be transposable to others, as epidemiology of urinary stone disease, demographic characteristics, access to technologies and education differ from one country to another. This has been acknowledged by the authors, and it seems particularly important to recall the relatively low body mass index (BMI) found in this cohort (mean BMI < 25 kg/m2). Higher BMI values may arguably impact on outcomes of SMP.

We agree with the authors that both SMP and URS are safe and feasible treatment options for lower pole calculi. Importantly, expertise in percutaneous surgery is warranted for cases presenting impaired retrograde access. Nevertheless, in light of constant and rapid advances in the field of URS, it seems that superiority, if any, of percutaneous nephrolithotomy in terms of SFR is to be tackled by URS in the years to come. This is well illustrated in the present study where 1–2‐cm stones were treated by URS with a laser power range between 5 and 20 W within 52 min in 50% of all cases and within 75 min in 86.4% of all cases (calculations based on values from Table 2 [1]).

Notably, no consensus has been agreed for the definition of different sizing of percutaneous nephrolithotomy instruments [4]. In the present study, the authors refer to SMP as the use of maximal tract dilation and instrument size up to 14 F. The authors justify size reduction of instruments considering the possible reduced blood loss in favor of smaller access sheaths compared with conventional percutaneous nephrolithotomy [5]. Nevertheless, it should be recalled that whether conventional, mini, super‐mini or any other‐size percutaneous nephrolithotomy, these techniques all share the same fundamental methods of access to intrarenal cavities; therefore, their inherent potential risks and harms – particularly bleeding and iatrogenic organ injury – fundamentally remain the same. This might partly explain why solitary kidney was an exclusion criterion in this study. In contrast, URS respects the delineation of the urinary tract [6]. URS is therefore likely to maintain a superior safety profile, even if further efforts are made at reducing the size of percutaneous nephrolithotomy instruments in the years to come.

The authors’ statement that SMP is more effective than URS to treat 1–2‐cm lower pole calculi should be interpreted in the context of the above. We hope that our comments will aid the correct interpretation of the data presented in this study. We congratulate the authors for the originality of their study, and we encourage them to continue evaluating indications, efficiency and safety of SMP.

References

  1. Zeng G, Zhang T, Agrawal M et al. Super‐mini percutaneous nephrolithotomy (SMP) vs retrograde intrarenal surgery for the treatment of 1‐2 cm lower‐pole renal calculi: an international multicentre randomised controlled trial. BJU Int 2018; 122: 1034–40
  2. Kishore TA, Pedro RN, Hinck B, Monga M. Estimation of size of distal ureteral stones: noncontrast CT scan versus actual size. Urology 2008; 72: 761–4
  3. Zhu W, Liu Y, Liu L et al. Minimally invasive versus standard percutaneous nephrolithotomy: a meta‐analysis. Urolithiasis 2015; 43: 563–70
  4. Giusti G, Proietti S, Villa L et al. Current standard technique for modern flexible ureteroscopy: tips and tricks. Eur Urol 2016; 70: 188–94

 

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