Nishal Patel et al., 2024: SLAP Trial: Shock Wave Lithotripsy and Mechanical Percussion Therapy Post ESWL for Renal Calculi

Friday, 01 November 2024

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Nishal Patel 1 2 , Adrian Roe 1 , Donna Stanton 1 , Jay Roberts 3 , Akshay Kothari 1
1Department of Urology, The Prince Charles Hospital, Brisbane, Queensland, Australia.
2Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
3Department of Urology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.

Abstract

Methods: We conducted a prospective randomised control trial. Included patients were males and females greater than 18 years of age with single or multiple ipsilateral renal calculi of total ≤10 mm on plain X-ray and noncontrast CT KUB. ESWL was performed at a single centre, at supine position under general anaesthesia with maximum 3000 shocks at a rate of 100 shocks per minute. Patients were discharged and randomised to either the control arm or MPI therapy. MPI therapy was self-directed in a home setting for 10 minutes a day, three times per week. Both arms had standard follow-up at 12 weeks with a plain X-ray KUB. Patients in the control group were offered cross over to the MPI arm after 12 weeks if residual stone fragments were detected. Statistical analysis was performed using SPSS software via Chi squared and Fisher's exact tests. Ethical approval was obtained via the Prince Charles Hospital HREC Committee, HREC/2022/QPCH/84961.

Results: 70 patients met inclusion criteria and underwent ESWL, and 5 were withdrawn. 33 patients were randomised to the MPI group and 32 to the control group. MPI significantly increased the stone clearance rate anywhere in the kidney (87.9% in the MPI group versus 59.4% in the control group, p=0.089), as well as the clearance rate in the lower pole (91.7% in the MPI group versus 63.2% in the control group, p=0.022). Delayed percussion did not improve the clearance rate over primary percussion (p=0.835).

Conclusion: This study has shown that MPI can be effectively performed in a home setting without the need for medical supervision and results in improved stone clearance rates post ESWL. The main limitations to the study were the use of X-ray over CT during the follow-up and variability in MPI compliance and administration. Further research is warranted into standardising home MPI protocols. This trial is registered with ANZCTR387061.

Adv Urol. 2024 Mar 26:2024:7870425. doi: 10.1155/2024/7870425. eCollection 2024.
PMID: 38566931 PMCID: PMC10987243

Comments 1

Hans-Göran Tiselius on Friday, 01 November 2024 10:00

The outcome of SWL is determined by two factors, firstly the efficacy of stone disintegration and secondly how effectively stone fragments can be eliminated from the kidneys or ureters. The first factor depends on the properties and capacity of the lithotripter and how the equipment is handled. The second factor is determined by the intrarenal geometry and anatomy, particularly problematic for stones in the lower calyces. Accordingly, effective SWL alone very often is not enough for adequate fragment clearance. The latter shortcoming is the reason why methods have been developed based on inversion, percussion and diuresis to deal with the gravity dependent retention of fragments. Thereby good results have been reported, but not without significant clinical efforts.
The authors of this article organized a method for mechanical percussion and inversion (MPI) carried out in the patient’s home. That procedure comprised mechanical percussion for 10 minutes three times a week in a 30-45◦ declined position. Thirty minutes before this procedure the patients were instructed to drink 300 mL of water. However, the procedure cannot be completed without an assistant who will be responsible for the percussion. The instructions are given in a document handed over to the patient.
This is indeed a very good idea, and the essential outcome was that whereas 92% of the MPI-patients with lower calix stones became stone-free compared with only 63% stone free in a corresponding control group. The overall stone-free rates were 88% and 59%, respectively. It is of note that the authors considered patients with ≤4 mm fragments as stone-free. It is not mentioned, however, whether MPI resulted in clearance of fragments larger than 4 mm.
To arrange a series of MPI procedures at home is an ingenious idea that significantly reduces the cost of stone removal. But it seems necessary that the procedure is carried out in an optimal way. In the reviewer’s opinion it is ideal, if the patient at the time of SWL, carefully is shown, by a live or video demonstration, how the procedure should be carried out. This step should be accomplished in the presence of the patient as well as the presumed assistant. Otherwise, it is difficult to fully understand how forceful the percussion should be.
The authors can be congratulated to this low-cost MPI, which certainly can be further developed to get even better stone-free rates.
Finally, it stands to reason that SWL of lower calix stones without additional fragment-clearing procedures is suboptimal stone treatment and if RIRS is used as a complement, the favor of non-invasive SWL is lost.

Hans-Göran Tiselius

The outcome of SWL is determined by two factors, firstly the efficacy of stone disintegration and secondly how effectively stone fragments can be eliminated from the kidneys or ureters. The first factor depends on the properties and capacity of the lithotripter and how the equipment is handled. The second factor is determined by the intrarenal geometry and anatomy, particularly problematic for stones in the lower calyces. Accordingly, effective SWL alone very often is not enough for adequate fragment clearance. The latter shortcoming is the reason why methods have been developed based on inversion, percussion and diuresis to deal with the gravity dependent retention of fragments. Thereby good results have been reported, but not without significant clinical efforts.
The authors of this article organized a method for mechanical percussion and inversion (MPI) carried out in the patient’s home. That procedure comprised mechanical percussion for 10 minutes three times a week in a 30-45◦ declined position. Thirty minutes before this procedure the patients were instructed to drink 300 mL of water. However, the procedure cannot be completed without an assistant who will be responsible for the percussion. The instructions are given in a document handed over to the patient.
This is indeed a very good idea, and the essential outcome was that whereas 92% of the MPI-patients with lower calix stones became stone-free compared with only 63% stone free in a corresponding control group. The overall stone-free rates were 88% and 59%, respectively. It is of note that the authors considered patients with ≤4 mm fragments as stone-free. It is not mentioned, however, whether MPI resulted in clearance of fragments larger than 4 mm.
To arrange a series of MPI procedures at home is an ingenious idea that significantly reduces the cost of stone removal. But it seems necessary that the procedure is carried out in an optimal way. In the reviewer’s opinion it is ideal, if the patient at the time of SWL, carefully is shown, by a live or video demonstration, how the procedure should be carried out. This step should be accomplished in the presence of the patient as well as the presumed assistant. Otherwise, it is difficult to fully understand how forceful the percussion should be. 
The authors can be congratulated to this low-cost MPI, which certainly can be further developed to get even better stone-free rates.
Finally, it stands to reason that SWL of lower calix stones without additional fragment-clearing procedures is suboptimal stone treatment and if RIRS is used as a complement, the favor of non-invasive SWL is lost.

Hans-Göran Tiselius

The outcome of SWL is determined by two factors, firstly the efficacy of stone disintegration and secondly how effectively stone fragments can be eliminated from the kidneys or ureters. The first factor depends on the properties and capacity of the lithotripter and how the equipment is handled. The second factor is determined by the intrarenal geometry and anatomy, particularly problematic for stones in the lower calyces. Accordingly, effective SWL alone very often is not enough for adequate fragment clearance. The latter shortcoming is the reason why methods have been developed based on inversion, percussion and diuresis to deal with the gravity dependent retention of fragments. Thereby good results have been reported, but not without significant clinical efforts. The authors of this article organized a method for mechanical percussion and inversion (MPI) carried out in the patient’s home. That procedure comprised mechanical percussion for 10 minutes three times a week in a 30-45◦ declined position. Thirty minutes before this procedure the patients were instructed to drink 300 mL of water. However, the procedure cannot be completed without an assistant who will be responsible for the percussion. The instructions are given in a document handed over to the patient. This is indeed a very good idea, and the essential outcome was that whereas 92% of the MPI-patients with lower calix stones became stone-free compared with only 63% stone free in a corresponding control group. The overall stone-free rates were 88% and 59%, respectively. It is of note that the authors considered patients with ≤4 mm fragments as stone-free. It is not mentioned, however, whether MPI resulted in clearance of fragments larger than 4 mm. To arrange a series of MPI procedures at home is an ingenious idea that significantly reduces the cost of stone removal. But it seems necessary that the procedure is carried out in an optimal way. In the reviewer’s opinion it is ideal, if the patient at the time of SWL, carefully is shown, by a live or video demonstration, how the procedure should be carried out. This step should be accomplished in the presence of the patient as well as the presumed assistant. Otherwise, it is difficult to fully understand how forceful the percussion should be. The authors can be congratulated to this low-cost MPI, which certainly can be further developed to get even better stone-free rates. Finally, it stands to reason that SWL of lower calix stones without additional fragment-clearing procedures is suboptimal stone treatment and if RIRS is used as a complement, the favor of non-invasive SWL is lost. Hans-Göran Tiselius

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