Schnabel MJ et al, 2014: Incidence and risk factors of renal hematoma: a prospective study of 1,300 SWL treatments
Schnabel MJ, Gierth M, Chaussy CG, Dötzer K, Burger M, Fritsche HM
Department of Urology, University of Regensburg, Regensburg, Germany
Abstract
Shock wave lithotripsy (SWL) is the gold standard for the treatment of upper urinary tract stones. Despite being relatively non-invasive, SWL can cause renal hematoma (RHT). The aim of this study was to determine incidence and risk factors for RHT following SWL. 857 patients were included in a prospectively maintained database. The observation period spans from 2007 to 2012. 1,324 procedures were performed due to kidney stones. Treatment protocol included power ramping and shock wave frequency of 60-90 per minute as well as an ultrasound check within 3 days of SWL for all patients. Patients with RHT were analyzed, and treatment characteristics were compared with the complete population in a non-statistical manner due to the low event count. RHTs after SWL, sized between 2.6 × 0.6 cm and 17 × 15 cm, were verified in seven patients (0.53 %). In four patients, the RHT was asymptomatic. Three patients developed pain after SWL treatment due to a RHT. In one patient surgical intervention was necessary due to a symptomatic RHT, the kidney was preserved. The risk of RHT following SWL treatment of kidney stones is about 0.5 %. Clinically relevant or symptomatic RHTs occur in 0.23 %, RHTs requiring surgical intervention are extremely rare. Older age and vascular comorbidities appear to be risk factors for the development of RHT. The technical characteristics of SWL treatment and intake of low-dose acetylsalicylic acid due to an imperative cardiologic indication do not appear to influence the risk. Prospective studies are warranted.
Urolithiasis. 2014 Jan 14. [Epub ahead of print]
PMID:24419328[PubMed - as supplied by publisher]
Comments 1
Hematoma after SWL is such a rare event that the authors stated: "Due to the low number of events, this study lacks a complete statistically analysis. The postulated risk factors are based on remarkable findings in our RHT cases in context with the current literature." Their references do not include the publication by Razvi et al. (Razvi H, Fuller A, Nott L, Mendez-Probst CE, Leistner R, Foell K, Dave S, Denstedt JD. Risk Factors for Perinephric Hematoma Formation After Shock Wave Lithotripsy: A Matched Case-Control Analysis. J Endourol. 2012 Jun 19) reviewed in 2012. The latter results with the Storz SLX-F2 compare well with the present experience.
Razvi H, Fuller A, Nott L, Mendez-Probst CE, Leistner R, Foell K, Dave S, Denstedt JD. Risk Factors for Perinephric Hematoma Formation After Shock Wave Lithotripsy: A Matched Case-Control Analysis. J Endourol. 2012 Jun 19
ABSTRACT:
PURPOSE: To determine the incidence of and evaluate the potential risk of a symptomatic perinephric hematoma (PNH) following shock wave lithotripsy (SWL) with the Storz Modulith SLX-F2 device.
PATIENTS AND METHODS: Patient and treatment-related data from 6172 SWL treatments for proximal ureteral and kidney stones were collected prospectively from April 2006 to August 2010. Patients who developed signs or symptoms of a PNH following SWL were investigated with imaging studies. Each patient identified with a PNH was matched with 4 controls using sex, age (± 5 years), shock wave rate, energy and number, and no SWL within the previous 6 months as the matching variables. The baseline characteristics of the 21 cases and 84 controls were compared using Student's t-test. The independent variables of hypertension (intraoperative value > 140/90 mm Hg), anticoagulant/antiplatelet drugs, obesity (BMI ≥ 30) and diabetes were compared using a conditional logistic regression analysis. The dependent variable was hematoma.
RESULTS: Twenty-one (0.34%) adult patients (19 males, 2 females) with a mean age of 55.2 years developed a PNH following SWL with the Storz Modulith SLX-F2 device. Significant risk factors identified included intraoperative hypertension (HR 3.302, 1.066 – 10.230, p = 0.0384) and anticoagulant/antiplatelet medications (HR 4.198, 1.103 – 15.984, p = 0.0355). Diabetes (p = 0.1043) and obesity (p = 0.1021) were not associated with PNH.
CONCLUSIONS: A clinical PNH occurred in less than 1% of our population. This is consistent with reports from earlier generation devices. Risk factors identified for hematoma formation were intraoperative hypertension and the use of anticoagulant/antiplatelet drugs.
Peter Alken