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Featured researches published by A. Zielke.


Annals of Surgery | 2006

An aggressive surgical approach leads to long-term survival in patients with pancreatic endocrine tumors.

Volker Fendrich; Peter Langer; I. Celik; Detlef K. Bartsch; A. Zielke; Anette Ramaswamy; M. Rothmund

Objective:To evaluate the outcome of reoperations in patients with duodenopancreatic neuroendocrine tumors (PETs) in a tertiary referral center. Summary Background Data:The management of reoperations in PETs is still controversial. Methods:A total of 125 patients with PETs that underwent surgery between 1987 and 2004 at our institution were retrospectively evaluated. The diagnosis of PETs was based on clinical symptoms, biochemical tests, and histopathology. Patients with at least one reoperation were analyzed regarding clinical characteristics, pathology, operations, and long-term follow-up. Results:A total of 33 patients with a median age of 42 years were identified for this study: 13 patients had gastrinomas, 12 patients had nonfunctional islet cell tumors, 6 patients had insulinomas, and 2 patients had vipomas; 24 patients had sporadic NETs, 9 patients had a MEN-1-syndrome; 27 patients had histologically verified malignant tumors; 33 initial operations and 50 reoperations were performed. The initial procedures comprised 27 resections of the primary tumor and 6 explorative laparotomies; 28 of all reoperations were resections of distant metastases, including 15 liver resections; 19 resections of the pancreas or duodenum were performed during reoperations. The overall morbidity and mortality was 45% and 4.8%, respectively. After a median follow-up of 124 months (range, 16–384 months), 27 of 33 patients are still alive, 12 without evidence of disease. All 6 patients with benign tumors are still alive. The 5-, 10-, and actuarial 25-year survival rate for patients with malignant tumors were 81%, 72%, and 36%, respectively. The survival rate was significantly related to the patients age at time of initial operation and better in patients younger than 50 years compared with patients older than 50 years (P = 0.0007), and the presence or development of metastases (none or lymph node metastases versus distant metastases: P = 0.01). Conclusion:We show that an aggressive surgical approach leads to long-term survival in patients with malignant PETs. Although long-term cure can only be achieved in a proportion of patients with malignant PETs, significant long-term palliation can be achieved.


World Journal of Surgery | 1996

Surgical management for carcinoid tumors of small bowel, appendix, colon, and rectum

B. Stinner; O. Kisker; A. Zielke; M. Rothmund

Abstract. Carcinoid tumors occur most frequently in the gastrointestinal tract. Despite their ability to produce hormones, most of the midgut and hindgut carcinoids covered in this study are clinically silent, and the diagnosis is often not made before emergency surgery or evaluation for liver metastases. Because the rate of lymph node involvement and the prognosis of carcinoid tumors depend on their site and size, surgery refers to these two factors too. Lymph node metastases are most commonly found with small bowel carcinoids (20–45%), providing the rationale for an extended resection including the adjacent lymph node drainage area. Carcinoid tumors of the appendix < 1 cm in diameter rarely metastasize, simply requiring appendectomy for treatment. Lesions > 2 cm should be treated by right hemicolectomy because of their approximately 30% risk of lymph node metastases. Resection should always be done for carcinoid tumors of the colon resection as for adenocarcinomas. Rectal carcinoids < 2 cm rarely metastasize, directing the conclusion that for these smaller lesions local excision is sufficient; for lesions >2 cm a standard cancer resection should be performed provided distant metastases are absent. In general, the younger the patient or the larger the primary tumor, the more aggressive the treatment should be.


Langenbeck's Archives of Surgery | 2011

German Association of Endocrine Surgeons practice guidelines for the surgical treatment of benign thyroid disease

Thomas J. Musholt; Thomas Clerici; Henning Dralle; Andreja Frilling; Peter E. Goretzki; Michael Hermann; Jochen Kußmann; Kerstin Lorenz; Christoph Nies; Jochen Schabram; Peter Schabram; Christian Scheuba; Dietmar Simon; Thomas Steinmüller; Arnold Trupka; Robert A. Wahl; A. Zielke; Andreas Bockisch; Wolfram Karges; Markus Luster; Kurt Werner Schmid

IntroductionBenign thyroid disorders are among the most common diseases in Germany, affecting around 15 million people and leading to more than 100,000 thyroid surgeries per year. Since the first German guidelines for the surgical treatment of benign goiter were published in 1998, abundant new information has become available, significantly shifting surgical strategy towards more radical interventions. Additionally, minimally invasive techniques have been developed and gained wide usage. These circumstances demanded a revision of the guidelines.MethodsBased on a review of relevant recent guidelines from other groups and additional literature, unpublished data, and clinical experience, the German Association of Endocrine Surgeons formulated new recommendations on the surgical treatment of benign thyroid diseases. These guidelines were developed through a formal expert consensus process and in collaboration with the German societies of Nuclear Medicine, Endocrinology, Pathology, and Phoniatrics & Pedaudiology as well as two patient organizations. Consensus was achieved through several moderated conferences of surgical experts and representatives of the collaborating medical societies and patient organizations.ResultsThe revised guidelines for the surgical treatment of benign thyroid diseases include recommendations regarding the preoperative assessment necessary to determine when surgery is indicated. Recommendations regarding the extent of resection, surgical techniques, and perioperative management are also given in order to optimize patient outcomes.ConclusionsEvidence-based recommendations for the surgical treatment of benign thyroid diseases have been created to aid the surgeon and to support optimal patient care, based on current knowledge. These recommendations comply with the Association of the Scientific Medical Societies in Germany requirements for S2k guidelines.


British Journal of Surgery | 2005

Conventional bilateral cervical exploration versus open minimally invasive parathyroidectomy under local anaesthesia for primary hyperparathyroidism

Anders Bergenfelz; V. Kanngiesser; A. Zielke; C. Nies; M. Rothmund

Minimally invasive parathyroidectomy (MIP) has been introduced for the treatment of patients with primary hyperparathyroidism (pHPT). Thus far, only one randomized trial has compared video‐assisted MIP with conventional bilateral cervical exploration (BCE). The value of open MIP is therefore not known.


Langenbeck's Archives of Surgery | 2013

German Association of Endocrine Surgeons practice guideline for the surgical management of malignant thyroid tumors

Henning Dralle; Thomas J. Musholt; Jochen Schabram; Thomas Steinmüller; Andreja Frilling; Dietmar Simon; Peter E. Goretzki; Bruno Niederle; Christian Scheuba; Thomas Clerici; Michael Hermann; Jochen Kußmann; Kerstin Lorenz; Christoph Nies; Peter Schabram; Arnold Trupka; A. Zielke; Wolfram Karges; Markus Luster; Kurt Werner Schmid; Dirk Vordermark; Hans-Joachim Schmoll; Reinhard Mühlenberg; Otmar Schober; Harald Rimmele; Andreas Machens; Visceral Surgery; Radiooncology; Oncological Hematology

IntroductionOver the past years, the incidence of thyroid cancer has surged not only in Germany but also in other countries of the Western hemisphere. This surge was first and foremost due to an increase of prognostically favorable (“low risk”) papillary thyroid microcarcinomas, for which limited surgical procedures are often sufficient without loss of oncological benefit. These developments called for an update of the previous practice guideline to detail the surgical treatment options that are available for the various disease entities and tumor stages.MethodsThe present German Association of Endocrine Surgeons practice guideline was developed on the basis of clinical evidence considering current national and international treatment recommendations through a formal expert consensus process in collaboration with the German Societies of General and Visceral Surgery, Endocrinology, Nuclear Medicine, Pathology, Radiooncology, Oncological Hematology, and a German thyroid cancer patient support organization.ResultsThe practice guideline for the surgical management of malignant thyroid tumors includes recommendations regarding preoperative workup; classification of locoregional nodes and terminology of surgical procedures; frequency, clinical, and histopathological features of occult and clinically apparent papillary, follicular, poorly differentiated, undifferentiated, and sporadic and hereditary medullary thyroid cancers, thyroid lymphoma and thyroid metastases from primaries outside the thyroid gland; extent of thyroidectomy; extent of lymph node dissection; aerodigestive tract resection; postoperative follow-up and surgery for recurrence and distant metastases.ConclusionThese evidence-based recommendations for surgical therapy reflect various “treatment corridors” that are best discussed within multidisciplinary teams and the patient considering tumor type, stage, progression, and inherent surgical risk.


British Journal of Surgery | 2006

Negative stress-coping strategies among novices in surgery correlate with poor virtual laparoscopic performance†‡

Iyad Hassan; Peter Weyers; Katja Maschuw; B. Dick; Berthold Gerdes; M. Rothmund; A. Zielke

This study explored the impact of habitual stress‐coping strategies on the laparoscopic performance of novices in surgery using a virtual reality simulator.


Diseases of The Colon & Rectum | 2008

Prospective Evaluation of the Value of Magnetic Resonance Imaging in Suspected Acute Sigmoid Diverticulitis

Johannes T. Heverhagen; H. Sitter; A. Zielke; Klaus J. Klose

PurposeThe purpose of this study was to prospectively investigate patients with suspected acute colonic diverticulitis and to provide sensitivity, specificity, and interobserver agreement in a blinded trial.MethodsFifty-five patients (29 men; 59 ± 13 (range, 29–76) years) who reported to the emergency room with clinically suspected acute colonic diverticulitis were prospectively included in the study. All patients underwent magnetic resonance imaging scans of their abdomen before and after contrast agent administration. Two assessors blinded to all clinical, laboratory, and radiologic results evaluated the images separately.ResultsThe assessors reported colonic wall thickening, segmental narrowing of the colon, presence of diverticula, pericolic fatty infiltration, ascites, and abscesses. The assessors had to diagnose or rule out acute colonic diverticulitis. Sensitivities, specificities, positive, and negative likelihood ratios were derived. To determine interobserver agreement, a Cohen’s kappa coefficient was calculated. The two assessors exhibited sensitivities of more than 94 percent, specificities of 88 percent, positive likelihood ratios of more than 7.5, and negative likelihood ratios of less than 0.07. The kappa coefficient showed a significant, strong correlation between both assessors (κ = 0.68).ConclusionsMagnetic resonance imaging is investigator independent and provides high sensitivity and specificity for the diagnosis of acute colonic diverticulitis.


European Journal of Surgery | 2003

Influence of ultrasound on clinical decision making in acute appendicitis : A prospective study

A. Zielke; C. Hasse; H. Sitter; M. Rothmund

OBJECTIVE To assess the efficacy of ultrasound (US) as part of an algorithm to establish the indication for laparotomy in patients with suspected acute appendicitis. DESIGN Prospective investigation. SETTING University department of surgery, Germany. SUBJECTS 669 unselected patients admitted with suspected acute appendicitis. INTERVENTIONS Clinicopathological and procedural diagnoses of the algorithm were evaluated by correlating clinical and US findings with the results of laparotomy in 171 patients of whom 143 had acute appendicitis (prevalence 21%), and clinical as well as follow up data in the remainder. MAIN OUTCOME MEASURES The major clinicopathological variables were accuracy and positive predictive value; the rate of negative laparotomies and that of bad diagnostic errors served as the main procedural variables. RESULTS The overall sensitivity, specificity, and accuracy of the clinical diagnosis were 0.503, 0.950, and 0.855, respectively (positive predictive value: PPV 0.734, negative predictive value: NPV 0.875), those of ultrasound: 0.797, 0.967, and 0.931 (PPV 0.870, NPV 0.946); and 0.853, 0.927, and 0.940 at the end of the algorithm (PPV 0.762, NPV 0.958). However, the algorithm would have resulted in a significant increase in the rate of unnecessary laparotomies (from 13% to 16%). A revised clinical algorithm gave an overall diagnostic accuracy of 0.940 (p < 0.001) together with a low rate of negative laparotomies (11%, p < 0.01) and a significantly reduced number of diagnostic errors (from 71 to 21, p < 0.001). CONCLUSION Ultrasonography enabled us to diagnose acute appendicitis in more patients more often and more quickly than clinical evaluation alone, suggesting that US may produce a better outcome. The revised clinical algorithm may be helpful in the study of US in patients with suspected acute appendicitis in prospective randomised controlled clinical trials.


World Journal of Surgery | 2001

Clinical Decision-making, Ultrasonography, and Scores for Evaluation of Suspected Acute Appendicitis

A. Zielke; H. Sitter; Thomas Rampp; Thomas Bohrer; M. Rothmund

Abstract. Diagnosing acute appendicitis (aA) remains difficult. This study evaluated the utility of ultrasonography (US) compared to clinical decision-making alone and scoring systems to establish the indication for laparotomy in patients in whom aA was suspected. The prospectively documented data of 2209 patients admitted for suspicion of aA, who underwent US by one of 12 surgeons, formed a database in which the diagnostic and procedural performance of clinical decision-making, US, two scoring systems (Ohmann and Eskelinen scores), and clinical algorithms taking account of clinical and either US findings or score results, were retrospectively evaluated. The results of either modality were correlated with final diagnoses obtained by laparotomy in 696 patients, of whom 540 had aA (prevalence 24.45%) and follow-up data in the remainder. US had the highest specificity (97%, compared to 93% for the Ohmann and Eskelinen scores and 94% for the clinical evaluation and algorithms) and lowest overall rate of false-positive findings (negative laparotomy rate 7.6%). The scores were accurate in refuting the diagnosis of aA but otherwise not superior to US. The best overall diagnostic and procedural results were obtained with the algorithms that combined the results of either US or the Ohmann score with clinical evaluation, which produced the most favorable numbers of negative laparotomies, potential perforations, and missed cases of aA. US is the diagnostic standard of reference for patients with a possible diagnosis of aA. It yields diagnostic results superior to those of scoring systems and provisional clinical evaluation. However, the benefits of US by ultrasonographically trained surgeons are only fully appreciated within the context of clinical algorithms. The joint evaluation of score results and clinical evaluation may deliver information of similar accuracy.


Molecular and Cellular Endocrinology | 2007

Retinoic acid inhibits angiogenesis and tumor growth of thyroid cancer cells.

Sebastian Hoffmann; Andreas Rockenstein; Anette Ramaswamy; I. Celik; Anette Wunderlich; Susanne Lingelbach; Lorenz C. Hofbauer; A. Zielke

The anti-proliferative effect of retinoic acid (RA) has been documented for various tumors. Some 40% of patients with advanced and poorly differentiated thyroid cancer have been shown to respond to RA with increased uptake of radioiodine. It has been suggested that these effects may be caused by redifferentiation. Presently, little is known about the effects of RA on tumor angiogenesis, a prerequisite for growth and metastatic spread. The aim of the current study was to determine, whether tumor-induced angiogenesis of thyroid cancer is affected by RA. In vitro, the effect of 0.1/10 microM 13-cis RA on tumor cell number (MTT assay) and secretion of VEGF (ELISA) was analyzed in three thyroid cancer cell lines (FTC 236, C634 and XTC), as well as in endothelial cells (HUVEC) over several passages. In vivo, tumor growth, VEGF-expression and microvessel density (VSD) of RA treated thyroid cancer cells after xenotransplantation to nude mice was evaluated by morphometric analysis. In vitro, thyroid cancer cell lines responded to RA with reduced proliferation, ranging from 26 to 34% after 2 weeks of treatment and with up to 80% reduced secretion of VEGF. In vivo, tumor volumes of animals receiving RA were reduced by 33% (FTC 236), 27% (C643) and 6% (XTC), respectively. VSD of experimental tumors was diminished in the FTC 236 (25%) and the C643 cell line (15%), and almost unchanged in XTC tumors (7%). In vivo, VEGF-expression and apoptosis were not significantly affected by RA. In vitro, proliferation of HUVEC was inhibited by conditioned medium of C643 cells pretreated with RA (0.1/10 microM), as well as by administration of RA (0.1/10 microM). This study confirms thyroid tumor cell growth to be inhibited by RA. It demonstrates a decrease of in vitro VEGF accumulation and reduction of VSD in experimental undifferentiated thyroid carcinoma, suggesting that reduced angiogenesis may be an important mechanism responsible for the therapeutic effect of RA in thyroid cancer. Moreover, a direct anti-proliferative effect of RA on human endothelial cells is suggested.

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H. Sitter

University of Marburg

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C. Nies

University of Marburg

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C. Hasse

University of Marburg

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Lorenz C. Hofbauer

Dresden University of Technology

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