Ahmed AF. et al., 2021: Mini-percutaneous nephrolithotomy is a safe alternative to extracorporeal shockwave lithotripsy for high-density, renal stones: a prospective, randomised trial

Tuesday, 17 August 2021

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Ahmed AF, Abdelazeim H, ElMesery M, El-Feky M, Gomaa A, Tagreda I, Abozied H, Fahim A.
Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt.

Abstract

Objectives: To compare the outcomes of miniaturized percutaneous nephrolithotomy (mini-PNL) and extracorporeal shockwave lithotripsy (SWL) in the management of 10 to 20 mm, non-lower pole, renal stones.
Methods: This prospective randomized double-arm trial was conducted at a tertiary care hospital in Egypt from February to December 2020. Adult patients with single, non-lower pole, high density (≥1000 HU) renal stone were randomized to receive mini-PNL or SWL. The stone-free rate (SFR), operative, fluoroscopy and hospitalization times, blood loss, auxiliary procedures, retreatment, unscheduled hospital readmission, and complications were compared between groups.
Results: The primary analysis included 34 patients in the mini-PNL group and 33 patients in the SWL group. Overall, the SFR was 97.1% in the mini-PNL group compared with 30.3% in the SWL group (p<0.001). All patients in the SWL group required retreatment, and none of them were stone-free after the first SWL session. None of the patients in the mini-PNL group required retreatment. The overall operative time, fluoroscopy time, auxiliary procedure, retreatment, and unscheduled hospital readmission were significantly higher in the SWL group. The hospital stay and decrease in the hemoglobin level were significantly higher in the mini-PNL group. Both groups were comparable in the overall complication rate.
Conclusions: ini-PNL is more effective than SWL for treating 10 to 20 mm, high density, non-lower pole renal stones. mini-PNL has the advantages of high SFR and abolishing the need for retreatment and rehospitalization.
BJU Int. 2021 May 24. doi: 10.1111/bju.15493. Online ahead of print. PMID: 34028170.

Comments 1

Hans-Göran Tiselius on Tuesday, 17 August 2021 10:30

I have seen so many, and in fact too many, reports on comparative studies in which SWL and various endoscopic procedures have been used. The reports are retrospective, randomized or, increasingly common, systematic reviews.

As expected, lower stone free rates are reported with SWL than with more endoscopic and more invasive methods. Literature results are similar, only the percentages vary. The reason for that is how patients were selected, stone composition and intrarenal anatomy. Moreover, the result was judged after one or > one treatment session.

It stands to reason that when stones are treated under vision with the chance to actively remove stones and stone fragment, the stone-free rate (SFR) will be better than when the outcome depends on passive passage of fragments. It is repeatedly emphasized that the expertise of the endourologist is fundamental for successful stone removal. For SWL it is also necessary with operator expertise to take the important and necessary steps before, during and after SWL. But nothing is mentioned about the experience of the SWL operator.

These different aspect as well as advantages and disadvantages of the different treatment modalities have been discussed continuously ever since SWL was invented more than 40 years ago.

The authors of this report found in an RCT between 34 treatments with mini-PNL and 33 with SWL that 97% and 30% became stone-free after the first session. One explanation for low SFR after SWL is of course that only hard (>1000 HU) stones were included. These results can be compared with data from a systematic review published in 2019 [1]. In that report the overall stone-free rates following treatment of lower pole stones were 61.5% for SWL, 75.5% for RIRS and 90.5% for PCNL

Hans-Göran Tiselius

Reference

1.Tsai S-H et al. Comparison of the efficacy and safety of shockwave lithotripsy, retrograde intrarenal surgery, percutaneous nephrolithotomy, and minimally invasive percutaneous nephrolithotomy for lower-pole renal stones. A systematic review and network meta-analysis. Medicine 2020; 99:10

As expected, lower stone free rates are reported with SWL than with more endoscopic and more invasive methods. Literature results are similar, only the percentages vary. The reason for that is how patients were selected, stone composition and intrarenal anatomy. Moreover, the result was judged after one or > one treatment session.

It stands to reason that when stones are treated under vision with the chance to actively remove stones and stone fragment, the stone-free rate (SFR) will be better than when the outcome depends on passive passage of fragments. It is repeatedly emphasized that the expertise of the endourologist is fundamental for successful stone removal. For SWL it is also necessary with operator expertise to take the important and necessary steps before, during and after SWL. But nothing is mentioned about the experience of the SWL operator.

These different aspect as well as advantages and disadvantages of the different treatment modalities have been discussed continuously ever since SWL was invented more than 40 years ago.

The authors of this report found in an RCT between 34 treatments with mini-PNL and 33 with SWL that 97% and 30% became stone-free after the first session. One explanation for low SFR after SWL is of course that only hard (>1000 HU) stones were included. These results can be compared with data from a systematic review published in 2019 [1]. In that report the overall stone-free rates following treatment of lower pole stones were 61.5% for SWL, 75.5% for  RIRS and 90.5% for PCNL

Hans-Göran Tiselius

Reference

1.Tsai S-H et al. Comparison of the efficacy and safety of shockwave lithotripsy, retrograde intrarenal surgery, percutaneous nephrolithotomy, and minimally invasive percutaneous nephrolithotomy for lower-pole renal stones. A systematic review and network meta-analysis. Medicine 2020; 99:10

I have seen so many, and in fact too many, reports on comparative studies in which SWL and various endoscopic procedures have been used. The reports are retrospective, randomized or, increasingly common, systematic reviews. As expected, lower stone free rates are reported with SWL than with more endoscopic and more invasive methods. Literature results are similar, only the percentages vary. The reason for that is how patients were selected, stone composition and intrarenal anatomy. Moreover, the result was judged after one or > one treatment session. It stands to reason that when stones are treated under vision with the chance to actively remove stones and stone fragment, the stone-free rate (SFR) will be better than when the outcome depends on passive passage of fragments. It is repeatedly emphasized that the expertise of the endourologist is fundamental for successful stone removal. For SWL it is also necessary with operator expertise to take the important and necessary steps before, during and after SWL. But nothing is mentioned about the experience of the SWL operator. These different aspect as well as advantages and disadvantages of the different treatment modalities have been discussed continuously ever since SWL was invented more than 40 years ago. The authors of this report found in an RCT between 34 treatments with mini-PNL and 33 with SWL that 97% and 30% became stone-free after the first session. One explanation for low SFR after SWL is of course that only hard (>1000 HU) stones were included. These results can be compared with data from a systematic review published in 2019 [1]. In that report the overall stone-free rates following treatment of lower pole stones were 61.5% for SWL, 75.5% for RIRS and 90.5% for PCNL Hans-Göran Tiselius Reference 1.Tsai S-H et al. Comparison of the efficacy and safety of shockwave lithotripsy, retrograde intrarenal surgery, percutaneous nephrolithotomy, and minimally invasive percutaneous nephrolithotomy for lower-pole renal stones. A systematic review and network meta-analysis. Medicine 2020; 99:10

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