Choo MS et al, 2018: The transgluteal approach to shockwave lithotripsy to treat distal ureter stones: a prospective, randomized, and multicenter study.
Choo MS, Han JH, Kim JK, Shin TY, Lee WK, Lee SK, Lee SH.
Department of Urology, Hallym University Songtan Sacred Heart Hospital, Hwaseong, Korea.
Department of Urology, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea.
PURPOSE: We compared the outcomes of SWL to treat distal ureter stones with regard to the conventional prone and supine positions using the transgluteal approach through the greater sciatic foramen.
METHODS: A prospective, randomized, single-blind, and multicenter study was conducted between October 2014 and July 2015. The inclusion criteria were radio-opaque distal ureter stones with a maximum diameter of 0.5-2 cm as measured on a CT scan. The included 160 patients were randomly assigned to two groups: the prone group (n = 80; treated in the conventional prone position) and the transgluteal group (n = 80; treated in the supine position using a transgluteal approach). In the latter group, the focused shock wave was transmitted through the greater sciatic foramen with the head positioned at a 40° angle to the vertical. "Stone-free" was defined as the complete clearance of stone fragments, assessed using a CT scan at 2 weeks after treatment. Overall satisfaction was self-reported using a 0-5 Likert scale.
RESULTS: The overall efficacy was 66.9%. The stone-free rate was significantly higher in the transgluteal group (72.6%) than in the prone group (54.7%; odds ratio 2.413, 95% CI 1.010-5.761, P = 0.023). No serious adverse events due to treatment were observed in either group. The satisfaction score of the transgluteal group was 4.21 ± 0.81, and 83.6% were willing to repeat the same procedure if necessary.
CONCLUSIONS: SWL using the transgluteal approach via a supine position through the greater sciatic foramen was more effective than via the conventional prone position. Furthermore, this approach provided a comparably safe and satisfactory procedure.
World J Urol. 2018 Mar 16. doi: 10.1007/s00345-018-2244-4. [Epub ahead of print]
The authors can be congratulated to a successfully completed randomized comparison of SWL of distal ureteral stones with the patients in prone and supine position. It is my own experience, however, that there is no standard procedure or position for SWL of distal ueteral stones.. Rather is it necessary to use an individualized strategy in which attention is paid to he possible interference between the shock wave path and skeletal structures or intestinal gas. The key to success always is to make sure that there is free passage of the shockwave to the stone .
The authors claim that treatment in the prone position is the conventional way to treat these patients, but I am not at all sure that this conclusion is correct. The first patients with distal ureteral stones that we treated with the Dornier HM3 lithotripter had the shock waves administered transgluteally .
The stone-free rate after the first session in this report was slightly lower than expected and whether this outcome is explained by the lithotripter or the lack of analgesics is not known.
It is my own experience that many patients find the prone position more comfortable than the supine.
In the report there are two complications or "harms" mentioned, One is bowel perforation when shockwaves encounter intestinal gas. Apart from the loss of energy and lack of disintegration the risk of bowel perforation is extremely low and I have not seen this complication during more than 25 years of clinical experience. The other "harmful effect" is
hemauria, but this should be considered as an expected effect of stone disintegration.
My own strategy is that for SWL treatment of distal ureteral stones use the position (prone or supine) that is most likely to allow for no or minimal loss of energy.
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