Kang HW et al, 2018: Predictive factors and treatment outcomes of Steinstrasse following shock wave lithotripsy for ureteral calculi: A Bayesian regression model analysis.
Kang HW, Cho KS, Ham WS, Kang DH, Jung HD, Kwon JK, Choi YD, Lee JY.
Department of Urology, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Korea.
Department of Urology, Gangnam Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
Department of Urology, Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
Department of Urology, Inha University School of Medicine, Incheon, Korea.
Department of Urology, Yongin Severance Hospital,Yonsei University Health System, Yongin, Korea.
Department of Urology, Severance Check-Up, Yonsei University Health System, Seoul, Korea.
Purpose: This study aims to assess the predictive factors and treatment outcomes of Steinstrasse formation following shock wave lithotripsy (SWL) for ureter stone.
Materials and Methods: The medical records of 1,418 ureter stone patients who underwent one-session SWL from November 2005 to May 2013 at our medical institute were retrospectively reviewed. Finally, 551 patients met inclusion criteria. Maximal length and location of stone, stone attenuation (Hounsfield units), and skin-to-stone distance (SSD) were determined on pretreatment non-contrast computed tomography.
Results: Of 551 patients, 12 patients (2.2% of total cohort) developed Steinstrasse after one-session SWL. The Steinstrasse incidence was significantly associated with stone size, stone attenuation value, and SSD. Prophylactic ureter stenting was not a statistically significant predictor of Steinstrasse formation. After propensity-score matching, Steinstrasse group showed a significant shorter SSD compare to non-Steinstrasse group. Multivariate logistic regression and Bayesian analysis revealed that stone size, stone attenuation and SSD were significant predictor of Steinstrasse formation following SWL for ureter stone. The Steinstrasse resolved spontaneously in six patients and remaining six patients were treated by additional SWL. None of patients with Steinstrasse required ureteral stenting, percutaneous drainage, or consequent surgical intervention.
Conclusions: Steinstrasse formation following SWL for ureter stone was rare event but no negligible. Large stone size, high stone attenuation and short SSD were significant predictors of Steinstrasse formation following SWL for ureter stone. Majority of patients with Steinstrasse formation could be treated conservatively in this clinical scenario.
Investig Clin Urol. 2018 Mar;59(2):112-118. doi: 10.4111/icu.2018.59.2.112. Epub 2018 Feb 1. FREE ARTICLE
This is how the authors explain the fact that a short SSD provoked Steinstrasse:
“… in ureter stones with relatively short SSDs, the effectiveness of shock waves can be determined in the early phase of SWL. At that time, a relatively large fragmented stone may migrate into the lower ureter by peristaltic movement of ureter, which can induce inappropriate stone focusing and patient positioning in the late phase of SWL.” The ESWL treatment was terminated early, “when the stone identification became difficult during SWL”. May be a premature treatment termination with fragments too big to pass could be the reason for Steinstrasse but the data given do not allow this conclusion.