Patel SR et al, 2011: Quantification of preoperative stone burden for ureteroscopy and shock wave lithotripsy: current state and future recommendations
Patel SR, Nakada SY
Department of Urology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705-2281, USA
OBJECTIVES: To determine which preprocedure imaging modality was used and how the stone burden quantification was assessed before shock wave lithotripsy (SWL) and ureteroscopy (URS) in published studies.
MATERIAL AND METHODS: References were searched in the MEDLINE database using the terms "shock wave lithotripsy" and "ureteroscopy," excluding "percutaneous nephrolithotomy" from January 2007 to January 2009. The inclusion criteria for our study included clinical trials published in English with >20 patients and measurement of pretreatment stone size.
RESULTS: Of the 198 studies in our initial MEDLINE search, 101 met the inclusion criteria. Of the 101 studies, 61 had evaluated SWL and 40 had evaluated URS. Also, 78 studies (77%) had quantified the stone burden in 1 dimension, 19 (19%) in 2 dimensions, and 4 (4%) in 3 dimensions. For SWL, the imaging modalities used to assess the stone burden included 24 mixed (40%), 10 noncontrast-enhanced computed tomography (16%), 12 plain abdominal film (20%), and 5 intravenous urography (8%); 10 studies (16%) did not mention the imaging modality used. For URS, the imaging modalities used to assess the stone burden included 15 mixed (38%), 8 noncontrast-enhanced computed tomography (20%), and 3 plain abdominal film (7%); 14 studies (35%) did not mention the imaging modality used.
CONCLUSIONS: Heterogeneity exists in the published data regarding the imaging modality used both before URS and SWL. Up to one third of all studies for both URS and SWL did not mention the imaging modality used to quantify the stone burden. Standardization of preprocedure imaging and its reporting in published studies is needed to better assess the pretreatment stone burden and compare the treatments of stone disease.
Copyright © 2011 Elsevier Inc. All rights reserved.
Urology. 2011 Aug;78(2):282-5. doi: 10.1016/j.urology.2010.12.009. Epub 2011 Feb 5
PMID: 21296390 [PubMed - indexed for MEDLINE]
This article brings into focus the importance of how the stone burden is measured and reported. A representative estimate of the size of the stone is of importance both for decisions on treatment and for appropriate evaluation of the treatment result. A retrospective analysis was carried out in 101 publications and it was concluded that 77% of the authors had measured the stone size in only one dimension, 19% in two and 4% in three dimensions. Moreover, different examination modalities (NCCT, KUB, KUB+US) give different results for technical reasons. It is emphasized that a better assessment of the stone burden is necessary.
The authors claim that despite the considerable radiation exposure with NCCT, this examination nevertheless should remain the standard primary imaging modality. On the other hand KUB should be chosen for follow-up.
With access to appropriate soft-ware it would be desirable if future reports on ESWL and other stone removing procedures are based on more accurate measurements. It is in fact very difficult to compare treatment results and effects of different lithotripter techniques without knowledge of the pre-treatment stone burden.