Berndt Wowra

Gamma Knife Zentrum Krefeld, München, Bavaria, Germany

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Publications (85)

  • Christian Schichor · Anna-Maria Biczok · Kraus Theo · [...] · Berndt Wowra
    Article · Sep 2016 · Journal of Neurological Surgery, Part B: Skull Base
  • [Show abstract] [Hide abstract] ABSTRACT: Purpose: To compare quality of life (QoL) in patients with uveal melanoma after enucleation and stereotactic radiosurgery to that in an age-matched patient collective. Methods: QoL was assessed in a cross-sectional survey and compared among 32 uveal melanoma patients after enucleation, 48 patients after stereotactic radiosurgery (CyberKnife(®); Accuray(®) Incorporated, Sunnyvale, CA, USA), and an age-matched control group of 35 patients, using the SF-12 Health Survey. Statistical analysis was performed with Fisher's exact test, Student's t test, one-way ANOVA analysis, Wilcoxon rank-sum (Mann-Whitney test), and ordered logistic regression for multivariate analysis. Results: There was no significant difference in QoL between patients treated by stereotactic radiosurgery and the age-matched control group. After enucleation, patients presented significantly lower values in Physical Functioning (PF), Role Physical (RP), and Role Emotional (RE) compared to the radiosurgery and control group. To control for the overall QoL lowering effect of visual loss, the QoL of the patients who underwent enucleation was compared with the QoL of patients suffering severe functional loss after CyberKnife radiosurgery in a subgroup analysis, which showed no statistically significant difference. The number of comorbidities had a significant impact on QoL in multivariate analysis. Conclusions: Superior performance in PF, RP, and RE suggests that CyberKnife represents a suitable first-line therapy for uveal melanoma. In cases with painful amaurosis or vast tumor recurrence, enucleation can be performed with an acceptable QoL outcome.
    Article · Nov 2015 · Albrecht von Graæes Archiv für Ophthalmologie
  • Kirsten Eibl-Lindner · Christoph Fürweger · Martin Nentwich · [...] · Alexander Muacevic
    [Show abstract] [Hide abstract] ABSTRACT: The aim of the study was to analyze the local efficacy and eye retention rate after frameless, image-guided robotic radiosurgery against uveal melanoma. A total of 217 patients, mostly with medium and large unilateral uveal melanomas (3% small, 62% medium, and 35% large) were treated. The median age was 64 years (range 21-95 years). All patients underwent a single-session procedure beginning with retrobulbar anesthesia, followed by MRI and computerized tomography scanning to generate the treatment plan. The tumor dose was 18-22 Gy (mean, 20.3 Gy) prescribed to the 70% isodose line. Follow-up occurred at 3, 6, 12, and 18 months and yearly thereafter with clinical, ultrasound, and MRI studies. The median follow-up time was 26.4 months. All patients were treated in the frameless setup within 3 h. The actuarial 3- and 5-year eye retention rates were 86.7 and 73%, respectively. Local control at 3 and 5 years was 87.4 and 70.8%, respectively. Serviceable vision was maintained in 30.9% of patients at last follow-up. Treatment-induced glaucoma developed in 33 patients at a median 20.8 months (range, 5.8-54.0 months). Other adverse effects were hemorrhage (26 patients) and macular edema (seven patients). Frameless, single-session, image-guided robotic radiosurgery is an effective and straightforward treatment option for patients with medium and large uveal melanoma that are otherwise difficult to treat.
    Article · Oct 2015 · Melanoma research
  • [Show abstract] [Hide abstract] ABSTRACT: Dear Editor,In 1993, a 49-year-old male patient presented with pain in the left shoulder. CT and magnetic resonance tomography (MRT) scans revealed a lesion in the third thoracic vertebra with pre- and paravertebral soft tissue involvement. Laminectomy of the second and third thoracic vertebra and stabilizing spondylodesis were performed, and the tumor was partially removed. By immunohistochemical examination, the lesion was classified as plasmacytoma, IgA kappa. Serum electrophoresis showed no M protein. By immunofixation, an IgA kappa paraprotein was identified and immunoglobulin A was slightly elevated. All other laboratory parameters including peripheral blood counts, renal function, calcium, and other polyclonal immunoglobulins were within the normal range. The bone marrow puncture result and skeletal survey were without pathologic findings leading to the diagnosis of a localized plasmacytoma (solitary plasmacytoma of the bone). Therapeutic radiation therapy (36 Gy) involving the ...
    Article · Apr 2015 · Annals of Hematology
  • [Show abstract] [Hide abstract] ABSTRACT: CyberKnife spinal radiosurgery suffers from a lack of posterior beams due to workspace limitations. This is remedied by a newly available tracking modality for fiducial-free, respiration-compensated spine tracking in prone patient position. We analyzed the potential dosimetric benefit in a planning study. Fourteen exemplary cases were compared in three scenarios: supine (PTV=CTV), prone (PTV=CTV), and prone position with an additional margin (PTV=CTV+2 mm), to incorporate reduced accuracy of respiration-compensated tracking. Target and spinal cord constraints were chosen according to RTOG 0631 protocol for spinal metastases. Plan quality was scored based on four predefined parameters: dose to cord (D0.1cc and D1cc), high dose (V10Gy), and low dose (V4Gy) volume of healthy tissue. Prescription dose was 16 Gy to the highest isodose line encompassing 90% of the target. Results were related to target size and position. All plans fulfilled RTOG 0631 constraints for coverage and dose to cord. When no additional margin was applied, a majority of eight cases benefitted from prone position, mainly due to a reduction of V4Gy by 23% ± 26%. In the 2 mm prone scenario, the benefit was nullified by an average increase of V10Gy by 43% ± 24%, and an increase of D1cc to cord (four cases). Spinal cord D0.1cc was unchanged (< ± 1 Gy) in all but two cases for both prone scenarios. Conformity (nCI) and number of beams were equivalent in all scenarios, but supine plans used a significantly higher number of monitor units (+16%) than prone. Posterior beam access can reduce dose to healthy tissue in CyberKnife spinal radiosurgery when no additional margin is applied. When a target margin of 2 mm is added, this potential gain is lost. Relative anterior-posterior position and size of the target are selection criteria for prone treatment.
    Article · Sep 2014 · Journal of Applied Clinical Medical Physics
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    Full-text available · Article · Aug 2014
  • [Show abstract] [Hide abstract] ABSTRACT: Purpose: High dose local stereotactic radiosurgery was performed in select patients to improve local tumor control and overall survival. We report on patients with renal tumors treated with single fraction robotic stereotactic radiosurgery. Materials and methods: A total of 40 patients with a median age of 64 years who had an indication for nephrectomy and subsequent hemodialysis were entered in a prospective case-control study of single fraction stereotactic radiosurgery. Of the patients 11 had transitional cell cancer and 29 had renal cell cancer. Tumor response, renal function, survival and adverse events were estimated every 3 months. Followup was at least 6 months. Results: A total of 45 renal tumors were treated. Median followup was 28.1 months (range 6.0 to 78.3). The local tumor control rate 9 months after stereotactic radiosurgery was 98% (95% CI 89-99). There was a measurable size reduction in 38 lesions, including complete remission in 19. Renal function remained stable. Using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation median creatinine clearance was 76.8 (range 25.3 to 126.3) and 70.3 ml/minute/1.73 m(2) (range 18.6 to 127.3) at baseline and followup, respectively (p = 0.89). Grade I erythrodermia developed in 1 patient, 3 reported grade I fatigue and 2 reported grade I nausea. Nephrectomy was avoided in all cases. Conclusions: Single fraction stereotactic radiosurgery as an outpatient procedure is a treatment modality with short-term safety and efficacy. It avoids treatment related loss of renal function and hemodialysis in select patients with transitional or renal cell cancer. At short followup oncologic results were similar to those of other ablative techniques for renal tumors. To date functional results have been excellent. Further studies are needed to determine the long-term results and limits of stereotactic radiosurgery in this setting.
    Article · Aug 2014 · The Journal of Urology
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    Annemarie Klingenstein · Christoph Fürweger · Martin M Nentwich · [...] · Kirsten H Eibl
    [Show abstract] [Hide abstract] ABSTRACT: To assess quality of life in uveal melanoma patients within the first and second year after CyberKnife radiosurgery. Overall, 91 uveal melanoma patients were evaluated for quality of life through the Short-form (SF-12) Health Survey at baseline and at every follow-up visit over 2 years after CyberKnife radiosurgery. Statistical analysis was carried out using SF Health Outcomes Scoring Software and included subgroup analysis of patients developing secondary glaucoma and of patients maintaining a best corrected visual acuity (BCVA) of the treated eye of 0.5 log(MAR) or better. Analysis of variance, Greenhouse-Geisser correction, Student's t-test, and Fisher's exact test were used to determine statistical significance. Physical Functioning (PF) and Role Physical (RP) showed a significant decrease after CyberKnife radiosurgery, whereas Mental Health (MH) improved (P=0.007, P<0.0001 and P=0.023). MH and Social Functioning (SF) increased significantly (P=0.0003 and 0.026) in the no glaucoma group, MH being higher compared with glaucoma patients (P=0.02). PF and RP were significantly higher in patients with higher BCVA at the second follow-up (P=0.02). RP decreased in patients with BCVA<0.5 log(MAR) (P=0.013). Vitality (VT) increased significantly in patients whose BCVA could be preserved (P=0.031). Neither tumor localization nor size influenced the development of secondary glaucoma or change in BCVA. Although PF and RP decreased over time, MH improved continuously. Prevention of secondary glaucoma has a significant influence on both SF and MH, whereas preservation of BCVA affects VT. Emotional stability throughout follow-up contributes positively toward overall quality of life. CyberKnife radiosurgery may contribute to attenuation of emotional distress in uveal melanoma patients.
    Full-text available · Article · Sep 2013 · Melanoma research
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    [Show abstract] [Hide abstract] ABSTRACT: Radiosurgery has become an accepted treatment option for vestibular schwannomas. Nevertheless, predictors of tumor control and treatment toxicity in current radiosurgery of vestibular schwannomas are not well understood. To generate new information on predictors of tumor control and cranial nerve toxicity of single-fraction radiosurgery of vestibular schwannomas, we conducted a single-institution long-term observational study of radiosurgery for sporadic vestibular schwannomas. Minimum follow-up was 3 years. Investigated as potential predictors of tumor control and cranial nerve toxicity were treatment technology; tumor resection preceding radiosurgery; tumor size; gender; patient age; history of cancer, vascular disease, or metabolic disease; tumor volume; radiosurgical prescription dose; and isodose line. Three hundred eighty-six patients met inclusion criteria. Treatment failure was observed in 27 patients. History of unrelated cancer (strongest predictor) and prescription dose significantly predicted tumor control. The cumulative incidence of treatment failure was 30% after 6.5 years in patients with unrelated malignancy and 10% after ≥15 years in patients without such cancer (P < .02). Tumor volume was the only predictor of trigeminal neuropathy (observed in 6 patients). No predictor of facial nerve toxicity was found. On the House and Brackmann scale, 1 patient had a permanent one-level drop and 7 a transient drop of 1 to 3 levels. Serviceable hearing was preserved in 75.1%. Tumor hearing before radiosurgery, recurrence, and prescription isodose predicted ototoxicity. Unrelated malignancy is a strong predictor of tumor control. Tumor recurrence predominantly predicts ototoxicity. These findings potentially will aid future clinical decision making in ambiguous cases.
    Full-text available · Article · May 2012 · Neuro-Oncology
  • A Klingenstein · M Kufeld · B Wowra · [...] · U C Schaller
    [Show abstract] [Hide abstract] ABSTRACT: Nilotinib is a second generation tyrosine kinase inhibitor which is used in both first and second line treatment of chronic myeloid leukemia (CML). In the present work, the effects of nilotinib resistance on K562 cells were investigated at the molecular level using Fourier transform infrared (FT-IR) spectroscopy. Human K562 CML cells were exposed to step-wise increasing concentrations of nilotinib, and sub-clones of K562 cells resistant to 50_nM nilotinib were generated and referred to as K562/NIL-50 cells. Antiproliferative effects of nilotinib were determined by XTT cell proliferation assay. Changes in macromolecules in parental and resistant cells were studied by FT-IR spectroscopy. Nilotinib resistance caused significant changes which indicated increases in the level of glycogen and membrane/lipid order. The amount of unsaturated lipids increased in the nilotinib resistant cells indicating lipid peroxidation. The total amount of lipids did not change significantly but the relative proportion of cholesterol and triglycerides altered considerably. Moreover, the transcriptional status decreased but metabolic turn-over increased as revealed by the FT-IR spectra. In addition, changes in the proteome and structural changes in both proteins and the nucleus were observed in the K562/NIL-50 cells. Protein secondary structural analyses revealed that alpha helix structure and random coil structure decreased, however, anti-parallel beta sheet structure, beta sheet structure and turns structure increased. These results indicate that the FT-IR technique provides a method for analyzing drug resistance related structural changes in leukemia and other cancer types.
    Article · Mar 2012 · Technology in cancer research & treatment
  • Article · Mar 2012 · International journal of radiation oncology, biology, physics
  • Klingenstein A · Kufeld M · Wowra B · [...] · U. C. Schaller
    [Show abstract] [Hide abstract] ABSTRACT: Purpose of this study is to evaluate radiographic therapy response, clinical outcome and adverse effects of CyberKnife radiosurgery in patients suffering from orbital metastases. Sixteen orbital metastases originating from different solid cancers in fourteen patients were treated by single fraction CyberKnife radiosurgery. Radiographic response and clinical outcome were evaluated. The treated tumor volume ranged from 0.2 to 35 cm(3) (median 2.3 cm(3), mean 7.0 cm(3), SD ± 10.4 cm(3), CI 0.9-9.4 cm(3)). The prescription dose ranged from 16.5-21 Gy (median 18 Gy, mean 18.2 Gy, SD ± 1.2 Gy, CI 17.0-18.4 Gy). A no change situation was observed in nine lesions, partial remission in four as well as complete remission in one metastasis. Tumor growth was stabilized or regressive following CyberKnife therapy in 87% of the cases. Recurrence was observed in two cases (13%). Before therapy, three patients suffered from visual disturbance and five patients reported diplopia. Six patients had no initial symptoms. After therapy, one patient indicated improvement of the present visual deficit and two patients no change. Out of the two patients with persistent diplopia, two reported improvement after therapy and three no change. No progression of symptoms was noted in any of the cases. Fourteen out of sixteen treated lesions were stable or regressive following CyberKnife radiosurgery (87%). As no serious adverse effects were reported in this series, CyberKnife therapy was shown to be of great value for local management of orbital metastases.
    Article · Mar 2012 · Technology in cancer research & treatment
  • M Kufeld · B Wowra · A Muacevic · [...] · Jörg-Christian Tonn
    [Show abstract] [Hide abstract] ABSTRACT: Purpose of this study is to analyze local control, clinical symptoms and toxicity after image-guided radiosurgery of spinal meningiomas and schwannomas. Standard treatment of benign spinal lesions is microsurgical resection. While a few publications have reported about radiosurgery for benign spinal lesions, this is the first study analyzing the outcome of robotic radiosurgery for benign spinal tumors, treated exclusively with a non-invasive, fiducial free, single-fraction setup. Thirty-six patients with spinal meningiomas or schwannomas were treated, utilizing a robotic radiosurgery system (CyberKnife®, Accuray Inc. Sunnyvale CA), and were followed prospectively. Medical history, histology, clinical symptoms and radiographic outcome were recorded. Thirty-nine spinal lesions were treated because of tumor recurrence, remnants after microsurgery, multiple lesions, or rejection of open surgery. Median age was 45 years (range 18-80 years). Median target volume was 3.4 cm(3) (range 0.2-43.4 cm(3)). Histology revealed 28 schwannomas and 11 meningiomas (WHO grade I). All spinal levels were affected. Median prescription dose was 14 Gray (95% C.I. 13.4-14 Gy) to the 70% isodose. After a median follow-up of 18 months (range 6-50 months) no local tumor progression was detected. 20 lesions (51%) remained stable, 19 tumors (49%) decreased in size. One patient with schwannomatosis was treated repeatedly for three new tumor locations. Pain was the initial symptom in 16 of 25 schwannoma patients, and in 3 of 11 patients with meningiomas. Pain levels decreased in 8/19 patients. All but one patient with motor deficits remained clinically stable. No myelopathic signs where found. Single-session radiosurgery for benign spinal tumors in selected patients has proven to inhibit tumor progression within the observed period without signs of early toxicity. Radiosurgery offers an additional treatment option, if microsurgery is not feasible in cases of tumor recurrence, post-resection remnants, multiple lesions, or medical comorbidity.
    Article · Feb 2012 · Technology in cancer research & treatment
  • Berndt Wowra · Alexander Muacevic · J.-C. Tonn
    [Show abstract] [Hide abstract] ABSTRACT: Classic radiosurgery is a neurosurgical treatment concept for single-fraction irradiation of cerebral lesions not amenable to open surgery. Until recently it has been realized mainly by frame-based technologies (Gamma Knife; stereotactic linear accelerators). The CyberKnife described in 1997 is an image-guided frameless robotic technology for whole-body radiosurgery. It can be used for classic single-fraction radiosurgery and for hypofractionated treatments. The CyberKnife treatment procedure is completely non-invasive and can be repeated throughout the body if necessary. Brain metastases are an important and frequently treated indication of modern radiosurgery. Data concerning radiosurgical treatment of brain metastases with the CyberKnife are reviewed. Scientific evidence shows that the full-body applicability of the CyberKnife is not at the expense of an inferior intracranial treatment quality when compared to standard frame-based technology. The clinical results of CyberKnife single-fraction radiosurgery are in line with the published literature. The attractive therapeutic profile of CyberKnife radiosurgery is reflected by a high tumor control and a low toxicity and the repeatability of the treatments for recurrent metastases. Although hypofractionated treatments (in 3-5 fractions) of brain metastases have been performed with the CyberKnife to treat large metastases, the clinical significance of this new radiosurgical concept is unclear and requires further study. A new approach is to treat the resection cavity with radiosurgery after surgical removal of brain metastases. In this concept radiosurgery replaces fractionated radiation therapy as an adjunct to surgery. The initial results are very promising. The CyberKnife has been established as a modern non-invasive technology for intra- and extracranial radiosurgery. It adds to the oncological armamentarium and confers upon radiosurgery a greater emphasis as an oncological treatment concept.
    Article · Jan 2012 · Progress in neurological surgery
  • Berndt Wowra · Alexander Muacevic
    Chapter · Dec 2011
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    [Show abstract] [Hide abstract] ABSTRACT: Conventional external beam radiotherapy is a standard procedure for treatment of spinal metastases. In case of progression spinal cord tolerance limits further radiotherapy in pre-irradiated areas. Spinal stereotactic radiotherapy is a non-invasive option to re-treat pre-irradiated patients. Nevertheless, spinal radiosurgery results in relevant dose deposition within the myelon with potential toxicity. Aim of the study was to retrospectively analyse the efficacy and feasibility for salvage radiosurgery of spinal metastases. During a period of 4 years (2005-2009) 70 lesions in 54 patients were treated in 60 radiosurgery sessions and retrospectively analysed. Clinical (pain, sensory and motor deficit) and radiological (CT/MRI) follow-up data were collected prospectively after radiosurgery. Pain - as main symptom - was classified by the Visual Analogue Scale (VAS) score. Every patient received single session radiosurgery after having been treated first-line with conventionally fractionated radiotherapy. Kaplan-Meier method and life tables were used to analyse freedom from local failure and overall survival. At a median follow-up of 14.5 months the actuarial rates of freedom from local failure at 6/12/18 months were 93%, 88% and 85%, respectively. The median radiosurgery dose was 1 × 18 Gy (range 10-28 Gy) to the median 70% isodose. The VAS score of patients with pain (median 6) dropped significantly (median 4, p = 0.002). In 6 out of 7 patients worse sensory or motor deficit after SRS was caused by local or distant failures (diagnosed by CT/MRI). One patient with metastatic renal cell carcinoma developed a progressive complete paraparesis one year after the last treatment at lumbar level L3. Due to multiple surgery and radiosurgery treatments at the lumbar region and further local progression, the exact reason remained unclear. Apart from that, no CTC grade III or higher toxicity has been observed. By applying spinal radiosurgery relevant radiation doses can be limited to small parts of the myelon. This prevents myelopathic side effects and makes it an effective and safe treatment option for well-suited patients. Especially for previously irradiated patients with local failure or pain salvage SRS represents a valuable treatment option with high local control rates, low toxicity and significant pain reduction.
    Full-text available · Article · Dec 2011 · Radiation Oncology
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    Judith Nastjenka Wagner · Miriam Glaser · Berndt Wowra · [...] · Michael Strupp
    [Show abstract] [Hide abstract] ABSTRACT: Objectives: Patients with vestibular schwannoma (VS) frequently suffer from disabling vestibular symptoms. This prospective follow-up study evaluates vestibular and auditory function and impairment of quality of life due to vertigo, dizziness, and imbalance in patients with unilateral VS of different sizes before/after microsurgical or radiosurgical treatment. Methods: Thirty-eight patients with unilateral VS were included. Twenty-two received microsurgery, 16 CyberKnife radiosurgery. Two follow-ups took place after a median of 50 and 186.5 days. Patients received a standardized neuro-ophthalmological examination, electronystagmography with bithermal caloric testing, and pure-tone audiometry. Quality of life was evaluated with the Dizziness Handicap Inventory (DHI). Patient data was grouped and analyzed according to the size of the VS (group 1: <20 mm vs group 2: ≥20 mm). Results: In group 1, the median loss of vestibular function was +10.5% as calculated by Jongkees Formula (range -43 to +52; group 2: median +36%, range -56 to +90). The median change of DHI scores was -9 in group 1 (range -68 to 30) and +2 in group 2 (-54;+20). Median loss of hearing was 4 dB (-42; 93) in group 1 and 12 dB in group 2 (5; 42). Conclusion: Loss of vestibular function in VS clearly correlates with tumor size. However, loss of vestibular function was not strictly associated with a long-term deterioration of quality of life. This may be due to central compensation of vestibular deficits in long-standing large tumors. Loss of hearing before treatment was significantly influenced by the age of the patient but not by tumor size. At follow-up 1 and 2, hearing was significantly influenced by the size of the VS and the manner of treatment.
    Full-text available · Article · Aug 2011 · Frontiers in Neurology
  • Article · May 2011 · Radiotherapy and Oncology
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    [Show abstract] [Hide abstract] ABSTRACT: Objective: To determine the safety and feasibility after image-guided single fraction robotic stereotactic radiosurgery (SRS) in patients with bone metastases of prostate cancer. Materials and methods: Forty patients with 64 bone metastases of prostate cancer were prospectively enrolled in a single center study and underwent 54 consecutive outpatient single session SRS procedures during a 4-year period. F-18 choline PET/CT in addition to standard CT imaging was done prior to SRS in all patients. Nineteen patients were under anti-androgen therapy, 8 patients had undergone chemotherapy before SRS. Overall survival and freedom from local tumor recurrence was analyzed with the Kaplan-Meier method. Results: Mean follow-up was 14 months (3-48 months). Seventy-five percent of patients had a single bone metastasis. The median tumor volume was 13 cc. The mean prescribed tumor dose was 20.2 Gy (16.5-22 Gy). Eight patients had died at the time point of the data analysis. The actuarial 6-months, 12-months, and 24-months local tumor control rate was 95.5% (95% CI: 83.0-98.8) as measured by MRI and PET CT imaging. The median initial PSA before SRS was 5.4 ng/dl (CI: 1.4-8.2) and dropped to 2.7 ng/dl (CI: 0.14-10) after 3 months. One case of progressive neurological deficits was documented. Conclusions: This first report on single session, image-guided robotic SRS documents a safe, feasible, and patient-friendly treatment option in selected patients with bone metastases of prostate cancer.
    Full-text available · Article · Apr 2011 · Urologic Oncology
  • Article · Jan 2011

Publication Stats

2k Citations


  • 2000-2006
    • Gamma Knife Zentrum Krefeld
      München, Bavaria, Germany
  • 2002-2003
    • Ludwig-Maximilians-University of Munich
      • • Department of Neurosurgery
      • • Department of Urology
      München, Bavaria, Germany