Razvi H et al, 2012: Risk Factors for Perinephric Hematoma Formation After Shock Wave Lithotripsy: A Matched Case-Control Analysis
Razvi H, Fuller A, Nott L, Mendez-Probst CE, Leistner R, Foell K, Dave S, Denstedt JD
Western University, Division of Urology, Department of Surgery, London, Ontario, Canada
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
J Endourol. 2012 Nov;26(11):1478-82. doi: 10.1089/end.2012.0261. Epub 2012 Aug 27
PMID: 22712655 [PubMed - as supplied by publisher]
This is a well performed study with relevant information as it is based on - as the authors state – "the largest known series of patients treated on the latest generation lithotripter". There are no essential news on the causes of hematoma formation after ESWL. But the value lies in the demonstration that proper handling of a shock wave machine is essential. At first glance the data presented here and in the paper reviewed below (Evaluation of shock wave lithotripsy injury in the pig using a narrow focal zone lithotriptor by Connors et al. BJU Int. 2012) seem to give contradictory information. But taken together the letter publication only shows that the misuse of a lithotripter causes harm. Using a scalpel can also be very dangerous.