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Biomedical subjects

H Sitter

Publications and source records attributed to H Sitter.

At least 19 recordsLinked to original sources
PubMed2005

[A virtual reality simulator for objective assessment of surgeons' laparoscopic skill].

BACKGROUND: The aim of this study was to validate computed virtual reality simulation as a tool to assess laparoscopic skills and to establish whether the simulator allows differentiating between surgeons with different laparoscopic experience. METHODS: 27 physicians at the surgical department of the University of Marburg, Germany, with different experience in laparoscopic surgery were divided into three groups: experienced (group I), intermediate (group II), and novices (group III). Following a brief introduction to the virtual reality simulator (LapSim), each participant performed twice a training program consisting of seven tasks (examinations I and II). RESULTS: Comparison of experienced surgeons with less experienced laparoscopic physicians showed a significant (P<0.05) superiority of group I at examinations I and II in most exercises. The groups' difference was more obvious in examination II, since the technique was new for all participants during examination I. Tasks of low complexity in virtual reality such as camera navigation, which are performed by young, not yet responsible surgeons in real surgery, did not show significantly different results between the three groups. CONCLUSION: Differences in laparoscopic experience can be visualised with a virtual reality simulator, and thus a simulator is helpful for assessing surgeons' laparoscopic skills.

Clinical Competence↗
PubMed2004

A problem solving and decision making toolbox for approaching clinical problems and decisions.

In this paper, we begin by presenting three real patients and then review all the practical conceptual tools that have been suggested for systematically analyzing clinical problems. Each of these conceptual tools (e.g. Evidence-Based Medicine, Clinical Practice Guidelines, Decision Analysis) deals mainly with a different type or aspect of clinical problems. We suggest that all of these conceptual tools can be thought of as belonging in the clinician's toolbox for solving clinical problems and making clinical decisions. A heuristic for guiding the clinician in using the tools is proposed. The heuristic is then used to analyze management of the three patients presented at the outset.

Biomedical Research↗
PubMed2004

Classification of perioperative histamine-related reactions.

OBJECTIVE: Histamine release may cause anaphylactoid reactions. However, during anaesthesia and surgery especially cardiovascular effects may not be regarded as histamine-related. Therefore, we adapted the classical concept of histamine release reactions to the perioperative situation and validated the new paradigm. METHODS: Elevated plasma histamine (diagnostic gold standard) was correlated to potentially related intraoperative signs and symptoms. The validity, repeatability and sensitivity of the 'gold standard' was tested by ROC analysis in volunteers, who also received H1-/H2-histamine antagonists. Additionally, a dose-response relationship was determined in dogs using the histamine releaser compound 48/80. RESULTS: The 'gold standard' had a sensitivity of 96% (90%-100%) and a specificity of 93% (85%-100%). The reproducibility was proven by repeated injections of histamine. Skin reactions, tachycardia and hypertension were identified as histamine-related diagnostic variables. A dose-response curve of plasma histamine release was created. CONCLUSIONS: The defined 'gold standard' is valid for the diagnosis of histamine-related reactions during anaesthesia and surgery. It may help to identify patients, who could benefit from pre-anaesthetic antihistamine prophylaxis.

Animals↗
PubMed2004

[Haemorrhoidectomy: conventional excision versus resection with the circular stapler. Prospective, randomized study].

BACKGROUND AND OBJECTIVE: The goal of this study was to compare two surgical methods of treating for haemorrhoids that aim at closure of the wound: resection with a circular stapler and a conventional, closed haemorrhoidectomy. PATIENTS AND METHODS: 80 patients (41 males, mean age 47,1 years) with haemorrhoids stage 3 were randomized and treated with stapler haemorrhoidectomy (test group; n = 40) or had an haemorrhoidectomy according to Fansler and Anderson (control group; n = 40). Following a standardized study protocol we compared postoperative results on the operating day and one week, six weeks, six months and one year afterwards uni- and multivariate analysis and we also calculated the costs. RESULTS: The stapler haemorrhoidectomy proved to be the method causing significantly reduced pain in the early postoperative period so that the patients needed less pain relief. They were able to return to work earlier. One year after stapler haemorrhoidectomy there were three episodes of postoperative bleedings that required intervention, one in the control group. Six patients still had haemorrhoids stage 3, six patients over the age of 65 had persistent anal incontinence (I degrees according to Parks) with proven sphincter dysfunction and disturbances in voiding their bowel with resulting deterioration of quality of life, significantly more frequent than in the control group. CONCLUSIONS: Stapler haemorrhoidectomy cures stage 3 haemorrhoids on a long term basis in 84.2 % of patients, costing less than all alternative treatments. In some cases, it can be associated with postoperative complications.

Adult↗
PubMed2004

[Lateral, partial sphincter myotomy as therapy of chronic anal fissue. Long-term outcome of an epidemiological cohort study].

AIM: We observed a relatively high rate of severe forms of anal incontinence in patients who had undergone lateral, partial, internal, open sphincterotomy for chronic fissure in ano years ago in our clinic. An explicit investigation of pre- and postoperative data for a representative patient group was undertaken to find out whether this incidental finding proved to be meaningful. PATIENTS AND METHODS: The perioperative data from 523 patients who underwent sphincterotomy (Parks) between 1986 and 1997 were analyzed by uni- and multivariate analysis. RESULTS: Of 209 patients included in the study, 94.7% could be considered healed after operation. Up until the 12th postoperative week, 14.8% of patients were incontinent in stage I and II (Parks). This increased up to 21% at the time of follow-up, mainly in stage II and III, which significantly differed from a healthy control group. CONCLUSION: Lateral sphincterotomy leads in most cases to quick healing of the chronic fissure in ano with a low recurrence rate. The added effect of degenerative changes was observed to be linked, however, with a higher long-term rate of anal incontinence.

Adult↗
PubMed2004

Functional parameters before and after parathyroidectomy: a prospective, randomized long-term trial on different rat strains.

For clinical controls before and after parathyroidectomy and for evaluation of the function of transplants of parathyroid tissue, it is necessary to establish standard values of relevant laboratory parameters for donor and recipient animals as well as for different types of nutrition. Since no such data are yet available, it was the purpose to define such standards. In a prospective randomized trial on 400 rats of the Dark Agouti (DA) and Lewis strain, different functional laboratory parameters such as total calcium, intact parathyroid hormone, phosphate, 1.25-dihydroxyvitamin D, and alkaline phosphatase were measured under a standard and low calcium diet over a period of 40 weeks. Two hundred of these animals underwent a parathyroidectomy four weeks after the beginning of the study and specimens were evaluated histologically. For all eight different study groups normal values could be defined within tight limits for parameters which describe the function of the parathyroid gland or elements of calcium metabolism under different conditions. The optimal conditions for a transplantation model of parathyroid glands were established. Lewis-rats were identified as the ideal donor and DA rats as the better recipient animals. These data can serve as reference values for future studies on transplantation of the parathyroid without immunosuppression.

Alkaline Phosphatase↗
PubMed2003

Diagnostic score in appendicitis. Validation of a diagnostic score (Eskelinen score) in patients in whom acute appendicitis is suspected.

BACKGROUND AND AIM: At times, the diagnosis of acute appendicitis may be difficult. However, for minimum morbidity to be obtained, early and accurate diagnosis is essential. This study aimed to validate a scoring system proposed by Eskelinen et al. as an aid in making the diagnosis of appendicitis. PATIENTS AND METHODS: The prospectively documented data of a consecutive series of 2,359 patients admitted for suspicion of appendicitis were used for validation. Accuracy and positive predictive value were defined as the main overall performance parameters, as was the rate of unnecessary operations to assess changes of patient management. Overall performance was assessed by receiver-operator characteristics (ROC) analysis. RESULTS: Of 2,359 patients, 662 were proven to have acute appendicitis (prevalence of 28%). The overall sensitivity, specificity, positive and negative predictive value, and accuracy of the score were 0.79, 0.85, 0.68, 0.91 and 0.835 at a cut-off value of 55. Calibration of the score's cut-off value to 57 yielded more favourable results (0.72, 0.91, 0.76, 0.9 and 0.86), and the rate of unnecessary operations declined from 26.6% to 15.4% ( P<0.05, chi2). ROC analysis revealed an area index of 0.91. CONCLUSION: The Eskelinen score delivered acceptable clinical results only after calibration to a cut-off value of 57. The data from this study suggest the investigation of whether a calibrated score might be particularly instrumental in the pre-admission evaluation of the patient in whom appendicitis is suspected.

Acute Disease↗
PubMed2003

[Influence of processing and sterilization on the mechanical properties of pins made from bovine cortical bone].

In a biomechanical study pins made of xenogenous cortical bone were tested in vitro. Forty pins of 3 mm diameter and 60 mm length were made of eight different cattle tibiae and allocated to five different treatment groups. Freeze-dried pins served as control group. Pins of the second group were preserved in concentrated sodium chloride solution and defatted with acetone (Tuto-plast processing). Pins of groups three to five were treated with sodium chloride and acetone and afterwards sterilized by different means (ethylene oxide, autoclavation, or gamma radiation). All pins were subjected to a three-point-bending test and a shear test. We found that bending strength and shearing strength were most increased after sodium chloride and acetone treatment, whereas after sterilization with ethylene oxide or autoclaving, the stability of the pins was similar to the control group. The stability was considerably diminished after gamma radiation. Taking into account possible toxic side effects of ethylene oxide, we conclude that Tutoplast processing followed by autoclavation presents a reliable preparation method for the clinical use of implants made of bovine cortical bone.

Acetone↗
PubMed2003

Skeletal growth and long-term bone turnover after enterocystoplasty in a chronic rat model.

OBJECTIVE: To investigate skeletal growth and bone metabolism in a chronic animal model of urinary diversion. MATERIALS AND METHODS: Young male Wistar rats (120) were allocated randomly to four groups undergoing: ileocystoplasty, ileocystoplasty and resection of the ileocaecal segment, colocystoplasty, and controls. All animals received antibiotics for 1 week after surgery; half of each group remained on oral antibiotics. Bone-related biochemistry was measured in serum and urine. Dual-energy X-ray absorptiometry and peripheral quantitative computed tomography (pQCT) were used to determine bone mass ex vivo. RESULTS: Most (90%) of the rats survived the study period (8 months); six rats died from bowel obstruction at the level of the entero-anastomosis and four had to be killed because of persistent severe diarrhoea. Vital intestinal mucosa was found in all augmented bladders. There were no differences in bone length and volume. Loss of bone mass was almost exclusively in rats with ileocystoplasty and resection of the ileocaecal segment (-37.5%, pQCT, P < 0.01). There was no hyperchloraemic metabolic acidosis or gross impairment of renal function. Hypomagnesaemia, hypocalcaemia and decreased insulin-like growth factor-binding protein 3 were the only significant findings on blood analysis. Deoxypyridinoline crosslinks in urine were higher in rats with an enterocystoplasty than in controls. CONCLUSIONS: Enterocystoplasty in rats neither impairs skeletal growth nor bone quantity, but leads to significant loss of bone mass when combined with resection of the ileocaecal segment. Rarefaction of the trabecular network is confined to the metabolically highly active cancellous compartment, most likely as a consequence of intestinal malabsorption.

Absorptiometry, Photon↗
PubMed2002

[Analysis of factors affecting the prognosis of vertebral metastases].

The goal of this study was to evaluate factors for the prognosis of patients with metastatic spinal tumors. 139 patients with vertebral metastases were studied. The modified Tokuhashi Score (a preoperative score composed of six parameters) and single factors were analysed with statistical methods. The modified Tokuhashi Score showed a significant correlation (p = 0,0019) with survival time of patients. Additionally, only the Karnofsky Index as single parameter showed statistically significant correlation(p = 0.0016). Regarding the logistic regression, primary tumor, age, sex and Karnofsky Index were identified as prognostic factors for survival time. This trial could demonstrate that the Tokuhashi Score is a successful predicting tool for the assessment of prognosis of patients with vertebral metastases.

Adult↗
PubMed2001

Feasibility of MRI in the diagnosis of acute diverticulitis: initial results.

PURPOSE: The purpose of this study was to evaluate MRI as a diagnostic tool in patients with suspected acute sigmoid diverticulitis. Furthermore, we sought to develop an optimal imaging protocol in these patients. PATIENTS AND METHODS: Eleven patients with suspected acute diverticulitis were included in the study. All patients were imaged in a 1.0 T clinical scanner using a body-array coil. Imaging sequences were single-shot TSE, HASTE-, STIR- and TrueFisp- sequence. All were obtained in the frontal plane. The diagnosis was verified by a single experienced investigator, using ultrasound, and overall clinicopathological outcome. RESULTS: MRI enabled visualization of signs of an acute diverticulitis in all patients. However, the diagnosis of acute diverticulitis was obtained in 10 patients only. The mean imaging time was 17.5+/-5.5 min. STIR- and TrueFisp-sequences alone displayed all findings, e.g pericolonic exsudation, edema and segmental narrowing, whereas SSTSE and HASTE-sequences showed no additional information. Therefore, it appeared that the imaging protocol could be restricted to STIR- and TrueFisp-sequences. CONCLUSION: MRI is feasible as a fast, accurate and investigator-independent diagnostic tool in patients with suspected acute diverticulitis. To prove its value in comparison to computed tomography or ultrasound, further studies are needed.

Acute Disease↗
PubMed2001

Granulocyte-colony stimulating factor in the prevention of postoperative infectious complications and sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). Protocol of a controlled clinical trial developed by consensus of an international study group. Part one: rationale and hypothesis.

GENERAL DESIGN: Presentation of a novel study protocol to evalue the effectiveness of an immune modifier (rhG-CSF, filgrastim): prevention of postoperative infectious complications and sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). The rationale and hypothesis are presented in this part of the protocol of the randomised, placebo controlled, double-blinded, single-centre study performed at an university hospital (n = 40 patients for each group). OBJECTIVE: Part one of this protocol describes the concepts of three major sections of the study: Definition of optimum and sub-optimal recovery after operation. Recovery, as an outcome, is not a simple univariate endpoint, but a complex construction of mechanistic variables (i. e. death, complications and health status assessed by the surgeon), quality of life expressed by the patient, and finally a weighted outcome judgement by both the patient and the surgeon (true endpoint). Its conventional early assessment within 14-28 days is artificial: longer periods (such as 6 months) are needed for the patient to state: "I am now as well as I was before". Identification of suitable target patients: the use of biological response modifiers (immune modulators) in addition to traditional prophylaxes (i. e. antibiotics, heparin, volume substitutes) may improve postoperative outcome in appropriate selected patients with reduced host defence and increased immunological stress response, but these have to be defined. Patients classified as ASA 3 and 4 (American Society for Anaesthesiologists) and with colorectal cancer will be studied to prove this hypothesis. Choice of biological response modifier: Filgrastim has been chosen as an example of a biological response modifier because it was effective in a new study type, clinic-modelling randomised trials in rodents, and has shown promise in some clinical trials for indications other than preoperative prophylaxis. It has also enhanced host defence and has been anti-inflammatory in basic research. CONCLUSION: The following hypothesis will be tested in patients with operations for colorectal cancer and increased preoperative risk (ASA 3 and 4): is the outcome as evaluated by the hermeneutic endpoint (quality of life expressed by the patient) and mechanistic endpoints (mortality rate, complication rate, relative hospital stay, assessed by the doctor) improved in the group receiving filgrastim prophylaxis in comparison with the placebo group? Quality of life will be the first primary endpoint in the hierarchical, statistical testing of confirmatory analysis.

Bacterial Infections↗
PubMed2001

Granulocyte-colony stimulating factor in the prevention of postoperative infectious complications and sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). Protocol for a controlled clinical trial developed by consensus of an international study group. Part two: design of the study.

GENERAL DESIGN: Presentation of a new type of a study protocol for evaluation of the effectiveness of an immune modifier (rhG-CSF, filgrastim): prevention of postoperative infectious complications and of sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). This part describes the design of the randomised, placebo controlled, double-blinded, single-centre study performed at an university hospital (n = 40 patients for each group). OBJECTIVE: The trial design includes the following elements for a prototype protocol: * The study population is restricted to patients with colorectal cancer, including a left sided resection and an increased perioperative risk (ASA 3 and 4). * Patients are allocated by random to the control or treatment group. * The double blinding strategy of the trial is assessed by psychometric indices. * An endpoint construct with quality of life (EORTC QLQ-C30) and a recovery index (modified Mc Peek index) are used as primary endpoints. Qualitative analysis of clinical relevance of the endpoints is performed by both patients and doctors. * Statistical analysis uses an area under the curve (AUC) model for improvement of quality of life on leaving hospital and two and six months after operation. A confirmatory statistical model with quality of life as the first primary endpoint in the hierarchic test procedure is used. Expectations of patients and surgeons and the negative affect are analysed by social psychological scales. CONCLUSION: This study design differs from other trials on preoperative prophylaxis and postoperative recovery, and has been developed to try a new concept and avoid previous failures.

Clinical Protocols↗
PubMed2001

Granulocyte-colony stimulating factor in the prevention of postoperative infectious complications and sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). Protocol of a controlled clinical trial developed by consensus of an international study group. Part three: individual patient, complication algorithm and quality manage.

GENERAL DESIGN: Presentation of a new type of a study protocol for evaluation of the effectiveness of an immune modifier (rhG-CSF, filgrastim): prevention of postoperative infectious complications and of sub-optimal recovery from operation in patients with colorectal cancer and increased preoperative risk (ASA 3 and 4). A randomised, placebo controlled, double-blinded, single-centre study is performed at an University Hospital (n = 40 patients for each group). This part presents the course of the individual patient and a complication algorithm for the management of anastomotic leakage and quality management. OBJECTIVE: In part three of the protocol, the three major sections include: The course of the individual patient using a comprehensive graphic display, including the perioperative period, hospital stay and post discharge outcome. A center based clinical practice guideline for the management of the most important postoperative complication--anastomotic leakage--including evidence based support for each step of the algorithm. Data management, ethics and organisational structure. CONCLUSIONS: Future studies with immune modifiers will also fail if not better structured (reduction of variance) to achieve uniform patient management in a complex clinical scenario. This new type of a single-centre trial aims to reduce the gap between animal experiments and clinical trials or--if it fails--at least demonstrates new ways for explaining the failures.

Algorithms↗
PubMed2001

[Outcome of minimally invasive surgery. Qualitative analysis and evaluation of the clinical relevance of study variables by the patient and physician].

INTRODUCTION: Mechanistic study endpoints, evaluated exclusively by the physician, are mostly used in clinical studies evaluating new treatment modalities (e.g. laparoscopic cholecystectomy). Those endpoints often lack clinical relevance. The patient's opinion concerning the importance of a study endpoint is particularly important in the evaluation of minimally invasive procedures, which place special emphasis on patient comfort. METHODS: In a first step it was evaluated by meta-analysis, which clinical endpoints have been used for comparison of laparoscopic and conventional cholecystectomy. Furthermore, using a qualitative analysis it was investigated how important the individual study endpoints are for patients and physicians. Ten patients and five surgeons were questioned in a structured interview. RESULTS: Of all outcome variables used world-wide, approximately one third were hermeneutic study endpoints, depending on the quality of the study, but often the method of evaluation was insufficient. Only three of 215 endpoints (< 2%) were quality of life scores, an integrated concept of outcome was missing completely. The qualitative analysis confirms the claimed difference between isolated and integrated evaluation of treatment goals. The importance of postoperative death is underestimated by patients and physicians; postoperative pain is overestimated. Patients ranked the outcome variable "restoration of full physical fitness" as the most important study endpoint after avoidance of complications and death. It is underestimated in isolated evaluation and has not been used in the world literature at all. CONCLUSION: The analysis of clinical relevance of study endpoints should be the first and not the last step of studies to evaluate surgical technology. It cannot be based purely on intuition; it must make use of scientifically accepted techniques (e.g. qualitative analysis).

Attitude of Health Personnel↗
PubMed2001

Clinical decision-making, ultrasonography, and scores for evaluation of suspected acute appendicitis.

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.

Acute Disease↗