Biomedical subjects

Martin Posch

Publications and source records attributed to Martin Posch.

14 recordsLinked to original sources

PubMed2006

Implant survival in mandibles of irradiated oral cancer patients.

OBJECTIVE: The aim of this study was to analyze long-term implant survival in the mandible after radiotherapy and radical surgery in oral cancer patients. STUDY DESIGN: Between 1990 and 2003, 71 patients (15 females, 56 males; average age 57.8 years, range 16-84.1 years) were treated with dental implants after radiochemotherapy and ablative surgery of oral cancer. Radiation therapy was delivered in daily fractions of 2 Gy given on 25 days (total dose of 50 Gy). Oral defects were reconstructed microsurgically with jejunal, iliac crest or radial forearm grafts. Thereafter 316 dental implants were placed in the non-irradiated residual bone (84; 27%), irradiated residual bone (154; 49%) or grafted bone (78; 25%) at various intervals (mean interval 1.41 (+/- 1.01) years, range 0.34-6.35 years). RESULTS: The mean follow-up time after implant insertion was 5.42 (+/- 3.21) years (range 0.3-13.61 years). The overall 2-, 3-, 5-, and 8-year survival rates of all implants were 95%, 94%, 91% and 75%. Forty-four implants were lost in 21 patients during the observation period. Irradiation of the mandibular bone showed significantly (P = 0.0028) lower implant survival compared with non-irradiated mandibular bone. The 8-year survival rate in the non-irradiated residual bone (two loss), irradiated residual bone (29 loss) or grafted bone (13 loss) were 95%, 72% and 54%, respectively. Time of implantation after irradiation showed no statistically significant influence. Implant brand, length or diameter or the incidence of resective surgery on the mandible and gender of patients had no statistically significant influence on implant survival. CONCLUSION: Radiation therapy with 50 Gy was significantly related to shorter implant survival in mandibular bone. Survival was lowest in grafted bone. Time of implant placement had no statistically significant influence on survival under the conditions of this study. Although implant survival is lower in irradiated mandibles, implants significantly facilitate prosthodontic treatment and enhance outcome of oral rehabilitation in cancer patients.

Adolescent↗

PubMed2005

Testing and estimation in flexible group sequential designs with adaptive treatment selection.

Integrating selection and confirmation phases into a single trial can expedite the development of new treatments and allows to use all accumulated data in the decision process. In this paper we review adaptive treatment selection based on combination tests and propose overall adjusted p-values and simultaneous confidence intervals. Also point estimation in adaptive trials is considered. The methodology is illustrated in a detailed example based on an actual planned study.

Austria↗

PubMed2005

Prospective, randomized, multicenter, double-blind placebo-controlled trial comparing adjuvant interferon alfa and isotretinoin with interferon alfa alone in stage IIA and IIB melanoma: European Cooperative Adjuvant Melanoma Treatment Study Group.

PURPOSE: The combination of interferon alfa (IFNalpha) and isotretinoin has shown a direct antiproliferative effect on human melanoma cell lines, but it remained unclear whether this combination is more effective than IFNalpha alone in patients with metastatic melanoma. We evaluated safety and efficacy of IFNalpha and isotretinoin compared with IFNalpha alone as adjuvant treatment in patients with primary malignant melanoma stage IIA and IIB. PATIENTS AND METHODS: In a prospective, randomized, double-blind, placebo-controlled trial, 407 melanoma patients in stage IIA (301 patients) and IIB (106 patients) were randomly assigned to either IFNalpha and isotretinoin (isotretinoin group; 206 patients) or IFNalpha and placebo (placebo group; 201 patients) after excision of the primary tumor. IFNalpha was administered three times a week at a dose of 3 million units subcutaneously for 24 months. Isotretinoin at a dose of 20 mg for patients < or = 73 kg, 30 mg for patients greater than 73 kg, or placebo daily for 24 months. RESULTS: A scheduled interim analysis revealed no significant differences in survival rates, with the isotretinoin group and the placebo group showing 5-year disease-free survival rates of 55% (95% CI, 46% to 65%) and 67% (95% CI, 59% to 75%), respectively, and overall 5-year survival rates of 76% (95% CI, 67% to 84%) and 81% (95% CI, 74% to 88%), respectively. The trial was stopped for futility. CONCLUSION: The addition of isotretinoin to an adjuvant treatment of low-dose IFNalpha in patients with stage IIA and IIB melanoma had no significant effect on disease-free or overall survival and is therefore not recommended.

Adolescent↗

PubMed2005

Two-stage designs for experiments with a large number of hypotheses.

MOTIVATION: When a large number of hypotheses are investigated the false discovery rate (FDR) is commonly applied in gene expression analysis or gene association studies. Conventional single-stage designs may lack power due to low sample sizes for the individual hypotheses. We propose two-stage designs where the first stage is used to screen the 'promising' hypotheses which are further investigated at the second stage with an increased sample size. A multiple test procedure based on sequential individual P-values is proposed to control the FDR for the case of independent normal distributions with known variance. RESULTS: The power of optimal two-stage designs is impressively larger than the power of the corresponding single-stage design with equal costs. Extensions to the case of unknown variances and correlated test statistics are investigated by simulations. Moreover, it is shown that the simple multiple test procedure using first stage data for screening purposes and deriving the test decisions only from second stage data is a very powerful option.

Algorithms↗

PubMed2004

The German version of the Oxford Shoulder Score--cross-cultural adaptation and validation.

INTRODUCTION: The evaluation of health-related quality of life is an established criterion for the evaluation of therapeutic measurement. Especially in the English language, a great number of different questionnaires have been developed. The original, English-language 12-item Oxford shoulder score (OSS) is a recently developed and validated patient-completed outcome measure specifically designed for the evaluation of patients suffering from shoulder pathology other than instability. Because of the lack of a comparable instrument in German, this questionnaire was translated into German and subsequently tested for validity and reliability in a cross-sectional study. MATERIAL AND METHODS: Translation of the OSS was done according to the guidelines in the literature. One hundred two patients completed the German version of the OSS and the SF-36. Additionally, the Constant shoulder score and the UCLA shoulder score were included into the validation process. The psychometric properties feasibility and patient-burden parameters were also tested. RESULTS: The patients completed all questionnaires. The mean time required for completing the OSS was 3 min, 25 s; the mean time required for evaluation of the questionnaire was 35 s. The internal consistency tested by the Cronbach's alpha (0.94) was high. The reproducibility tested by two different methods showed no significant difference. The construct validity showed a significant correlation between the OSS and the other scores. CONCLUSION: The instrument proved to be valid by demonstrating the same correlations predicted by standard clinical assessments and a generic patient-based instrument. Application and evaluation in clinical trial proved feasible and minimally time consuming. Therefore, the German translation of the Oxford shoulder score is a valid and reliable tool, applicable to outcome studies on shoulder patients.

Adult↗

PubMed2004

HSP-72 expression in pre-transplant donor kidney biopsies and post-transplant outcome.

In experimental transplant models, upregulation of renal heat shock proteins (HSP) represents a new therapeutic tool to improve allograft survival. In this clinical study, we hypothesized that HSP-72 expression in pretransplant donor kidney biopsies predicts posttransplant outcome. Expression of HSP-72 in pretransplant biopsies was assessed by immunohistochemistry and in situ hybridization in 82 consecutive renal transplantations and clinical data were collected prospectively during the first six months posttransplant. Renal tubular expression of HSP-72 was low and not influenced by donor-, graft-, or procedure-related risk factors. Neither strength nor pattern of pretransplant HSP-72 staining discriminated allografts with complicated (40%) posttransplant courses from those without complications (60%). The low HSP-72 expression in pretransplant donor kidney biopsies failed to predict delayed graft function or acute rejection. These findings suggest that constitutive HSP-72 gene expression at the time of engraftment does not play a role in graft protection.

Adult↗

PubMed2004

Rehabilitation of the severely atrophied maxilla by horseshoe Le Fort I osteotomy (HLFO).

OBJECTIVE: The purpose of this study was to determine the long-term outcome of the horseshoe Le Fort I osteotomy (HLFO) as a preprosthetic operation technique for implant insertion in the extremely atrophied maxilla. STUDY DESIGN: 36 patients (8 male, 28 female, average age 57.6 years) underwent HLFO combined with iliac crest bone grafting. They were divided into 2 groups: group A with 12 patients who simultaneously received 100 implants; group B with 24 patients where 176 implants were inserted in 18 patients in a second-stage procedure. Clinical and radiographic outcome with regard to implant osseointegration, alveolar bone height in the canine and molar regions, peri-implant bone loss and satisfaction of patients (esthetics, masticatory function, overall treatment) were investigated in all cases. RESULTS: The overall 2-year failure-free fraction of implants was 95.5%; the 5-year failure-free fraction was 89.3%. In the 1-step group the 2-year and 5-year failure-free fractions were 95.9% and 86.9%, respectively, in the 2-step group 95.0% and 91.3% (log rank test P=.57). A total of 27 implants were lost during the entire follow-up: 14 in 6 patients of the 1-stage and 13 in 9 patients of the 2-stage group. The mean loss of alveolar bone after augmentation in the canine and molar regions was almost equal in both groups (overall means for the 2 regions 3.67 +/- 2.77 and 4.42 +/- 2.72 mm, respectively). The relationship between the jaws and thereby the esthetic profile could be improved in all cases. All patients were satisfied with the dental rehabilitation and the achieved new esthetic appearance. CONCLUSIONS: HLFO combined with iliac bone grafting is a feasible preprosthetic technique prior to implant insertion in cases of severe atrophy of the maxillary alveolar ridge, leading to satisfying implant survival and rehabilitation of function.

Adult↗

PubMed2004

Long-term implant survival in the grafted maxilla: results of a 12-year retrospective study.

OBJECTIVE: The aim of this study was to determine the long-term outcome of implant insertion in the augmented severely atrophied maxilla. STUDY DESIGN: Three hundred and twenty-four implants were inserted in 35 patients (eight males, 27 females, average age 57.6 years) in extremely atrophied maxillae after osteotomy and interposition of iliac crest bone. One hundred implants were installed in 12 patients simultaneously with the osteotomy and grafting; 224 implants were placed in 23 patients in a second procedure 6-12 months later. Implant parameters like osseointegration and peri-implant bone loss; peri-implant tissue parameters like bleeding, gingival and plaque index; and patients' satisfaction were evaluated. RESULTS: Of 324 implants, 29 (8.9%) were lost during the entire follow-up: 14 in six patients of the one-step and 15 in 11 patients of the two-step group. The overall input-output survival in 141.1 months was 91.1%. The overall 2-year failure-free fraction of implants was 95.5%; the 5-year failure-free fraction was 89.3%. In the one-step group, the 2 (5)-year failure-free fraction was 95.9% (86.9%), and in the two-step group 95% (91.3%) (log-rank test P=0.57). Marginal peri-implant bone loss was 1.7+/-1.3 mm mesial and 1.8+/-1.3 mm distal. CONCLUSION: Implant insertion after osteotomy and iliac bone grafting is a reliable operation method for the dental rehabilitation of the severely atrophied maxilla showing good long-term results.

Atrophy↗

PubMed2003

Quality of life in patients with non-metastatic differentiated thyroid cancer under thyroxine supplementation therapy.

GOALS: When thyroid and other cancers are "cured" it is often assumed that the patients are able to resume their normal lives. This was a cross-sectional study to evaluate health-related quality of life (HRQOL) and to identify rehabilitation needs of patients with non-metastatic thyroid cancer under thyroxine supplementation therapy. PATIENTS AND METHODS: Included in the study were 150 consecutive patients with differentiated thyroid cancer (age 52 +/- 14 years, range 25-83 years; male/female 39/111). All patients had a history of total thyroidectomy followed by radioiodine ablation, were free of metastatic disease and under levothyroxine treatment. The mean period since the diagnosis of thyroid cancer was 5.5 +/- 6 years (range 0-23 years). Health-related quality of life was evaluated using the SF-36 Health Survey. The findings were compared with sex- and age-matched reference values. RESULTS: "Role-emotional" and "Vitality" were significantly lower ( P<0.001 and P<0.005, respectively) in the group as a whole ( n = 150). In the subgroup of patients with a recent (less than 1 year) diagnosis of thyroid cancer ( n = 51), however, the following subscales were significantly lower: "Mental Health" ( P<0.01), "Role-emotional" ( P<0.001), "Role-physical" ( P<0.005), "Social functioning" ( P<0.005) and "Vitality" ( P<0.001). Multiple regression analysis identified a significant positive correlation between "Mental Health", "Physical functioning", "Vitality", "Role-emotional" and "Social functioning" with the time since initial diagnosis, and there was also a positive correlation between "Physical functioning", "Bodily pain" and "Role-emotional" with male gender. CONCLUSIONS: These findings indicate that "Vitality", "Role-physical", "Mental Health", "Role-emotional" and "Social functioning" are significantly impaired during the first year after diagnosis. Thereafter, quality of life improves correlating with the time since initial diagnosis. However, "Vitality" and "Role-emotional" remain permanently impaired in thyroid cancer patients. A multidisciplinary rehabilitation concept should include psychological support and an early start to exercise to improve physical performance of these patients leading to better HRQOL and to help them fulfill their social role earlier.

Adult↗

PubMed2003

Issues in designing flexible trials.

We outline the general framework of adaptive combination tests and discuss their relationship to flexible group sequential designs. An important field of applications is sample size reassessment. We discuss reassessment rules based on conditional power arguments using either the observed or the prefixed effect size. These rules tend to lead to large expected sample sizes for small actual effects. However, the application of a maximal bound for the second stage sample size leads to more favourable properties. Additionally, we consider an optimized reassessment rule in terms of expected sample sizes. Since the adaptive design does not use the classical test statistics for some types of sample size reassessments, the adaptive test may reject the null hypothesis while the classical one-sample test does not. We characterize sample size reassessment rules, where such inconsistencies are avoided. Finally, the extension of flexibility to the number of stages is explored. In the first interim analysis a second interim analysis is only planned if the chance to achieve a decision there is high. This leads to savings in the average number of interim analysis performed, without paying a noticeable price in terms of expected sample size.

Clinical Trials as Topic↗

PubMed2003

Factors that influence the duration of splint wear in peripheral nerve lesions.

OBJECTIVE: To assess the weekly frequency and overall duration of wear for splints used to treat peripheral nerve lesions and factors that possibly influence splint wear. DESIGN: A total of 78 patients (23 women, 55 men) who had been treated with a hand splint for peripheral nerve palsy were interviewed by telephone, based on a preformulated questionnaire. The duration of wear, reasons for terminating use, the effect of the splint, the patients' assessment of splint treatment, the patients' instruction, and the patients' level of education were recorded. Survival analysis for the entire period of wear and logistic regressions to determine factors that influence splint wear were performed. Comparison of effect scores between lesions in the dominant those in the nondominant hand were carried out with a test. RESULTS: The median duration of wear was 6 mo for daytime and 4 mo for nighttime splints. Daytime splints were worn by 85% and nighttime splints by 84% of patients for 5-7 days per week. The reported effect of the splint was the only significant factor that influenced the frequency of wear. The splint was reported to be significantly more effective in the dominant hand than in the nondominant hand. Numerically, radial nerve lesions and cock-up wrist splints were most common. CONCLUSION: Regular splint wear was registered in the majority of patients and was positively influenced by a good effect of the splint, which was reported to be better in the dominant hand.

Adult↗

PubMed2002

[Optimizing electrotherapy--a comparative study of 3 different currents].

Neuromuscular electrical stimulation can be used to increase strength of skeletal muscle. In neuromuscular electrical stimulation of innervated skeletal muscle, the application of the highest possible intensities of electricity is an important determinant of therapeutic success with regard to strength training. The therapeutic goal of "strengthening muscles" is opposed to the side effect of discomfort through the application of electricity. The aim of the present study was to compare three forms of electric current with respect to subjective tolerance and maximum achievable muscular strength. Twenty-nine healthy male volunteers were included in a single-blind study in which three forms of electric current were applied in a randomized fashion. The following types were compared: a short monophasic form, a biphasic form that was twice as long in terms of impulse duration, and a long monophasic form with an equal impulse duration than tht of the biphasic form and with an impulse form that corresponded to the short monophasic current. Stimulation was administered via surface electrodes placed on the knee extensors in the lower extremity on the right side. The intensity of the current was increased to the individual limit of tolerance or to a maximum of 100 mA. The main target parameter used to determine the success of treatment was the maximum electrically induced strength as a percentage of maximal voluntary contraction. The short monophasic form of electricity was associated with much less discomfort than the long monophasic and biphasic forms (p < 0.0001, p = 0.0062). Furthermore, the biphasic form was better tolerated (and therefore had a larger therapeutic range of application) than the long monophasic form (p = 0.041). The biphasic and long monophasic forms produced higher values for maximum electrically induced strength than did the short monophasic form (p = 0.0001, p = 0.0010). To summarize: the biphasic form had a larger range of therapeutic application than the long monophasic form. Furthermore, the biphasic form produced 40% more electrically induced strength than the short monophasic one. It may be concluded that, in terms of therapeutic application, the biphasic form of electric current is superior to the monophasic forms described in the present study.

Adult↗

PubMed2002

Reliability of EMG time-frequency measures of fatigue during repetitive lifting.

PURPOSE: To test the short-term and long-term reliability of time-frequency electromyographic (EMG) measures of fatigue during repetitive dynamic lifting and compare it with the reliability of median frequency (MF) EMG measures of fatigue during static lifting. METHODS: Fourteen' healthy male subjects (26 +/- 5 years) repetitively (12 lifts/min) lifted and lowered a box (29 x 25 x 23 cm, 13 kg) for 4.5 min during 3 different tests on 2 different days. EMG data and the biomechanics of motion were recorded. Before and after dynamic lifting, static maximum lifting tests were performed. At the end of each of the two sessions, subjects performed a static lift at 80% of their maximum lifting force for 30 s. RESULTS: Significant fatigue-related changes were observed during the lifting exercise via EMG time-frequency analysis at the paravertebral L5, L2, T10, and vastus lateralis (VL) electrode sites. Two parameters for assessing fatigue during dynamic contractions [i.e., the Instantaneous Median Frequency (IMDF) and its time dependent change] were shown to be reproducible both in the short-term (2 h) and long-term (2 wk). The corresponding ICCs reflecting the reproducibility of values between sessions were 96.9% (L5), 98.1% (L2), 90.1% (T10), 96.4% (UT), 98.0% (GM), 89.5% (VL), and 99.0% (BF), respectively. For most EMG recording sites, the reliability of the IMDF measures was not dependent upon the postural strategy that the subject used to accomplish the lifting task or on the subject's strength as measured via the static maximum lifting test. A comparison between the ICC values of the IMDF measures and those of the parameters utilized to assess fatigue during static sustained lifts [i.e., the Median Frequency (MDF) and its change during the test] revealed equally good reproducibility for most EMG recording sites. The respective ICC values that took into account time dependent trends for the IMDF parameter were 87.1% (L5), 62.4% (L2), 90.1% (T10), 0% (UT), 72.7% (GM), 45.4% (VL), and 100% (BF), and for the MDF parameter 94.9% (L5), 73.0% (L2), 80.9% (T10), 100% (UT), 89% (GM), 91.7% (VL), and 90.9% (BF), respectively. CONCLUSIONS: The time-frequency approach allows one to derive EMG spectral parameters that can be used to monitor muscle fatigue during dynamic real-world tasks such as lifting.

Adult↗

PubMedDate not supplied

Impact of pneumococcal vaccination on morbidity and mortality of geriatric patients: a case-controlled study.

BACKGROUND: Infections due to Streptococcus pneumoniae are the major cause of adult community-acquired pneumonia, especially in elderly persons with chronic medical conditions. Despite their well-documented efficacy against bacteraemic disease and deaths in the elderly population, pneumococcal polysaccharide vaccines are still very much underused. OBJECTIVE: A retrospective, case-controlled study was performed to investigate the impact of vaccination with a polysaccharide pneumococcal vaccine, together with other risk factors, on the incidence of pneumonia and deaths in patients in a long-stay geriatric hospital. METHODS: Subjects were 1,077 residents in a long-stay geriatric hospital in Vienna, Austria, including 359 patients diagnosed as having pneumonia during the period from July 1996 to October 1998 and 718 control subjects. Two controls resident in the hospital during the same time period were matched for each case according to demographic characteristics, chronic illness, and duration of stay in the geriatric ward. The vaccination status was established for all subjects. A logistic regression analysis was performed to assess the efficacy of vaccination and the impact of other cofactors on disease and death. RESULTS: In cases and controls, 514 (47.7%) had received a pneumococcal vaccine within 2 years prior to the study. There were no differences in demographic characteristics, underlying medical conditions, or duration of stay in the hospital between vaccinated and non-vaccinated patients. In patients diagnosed with pneumonia, 66% were unvaccinated. Logistic regression analysis showed that vaccination significantly decreased the risk of pneumonia (odds ratio 0.279; p < 0.0001). Of the cofactors tested, only gender (lower risk in males) and diabetes mellitus (higher risk) had any impact on disease risk and vaccine efficacy. There appeared to be a highly significant effect of vaccination, reducing the risk of all deaths (odds ratio 0.269; p < 0.0001) and deaths due to pneumonia (odds ratio 0.331; p < 0.0001). CONCLUSION: This study showed that vaccination with a polysaccharide pneumococcal vaccine is effective in all groups of geriatric subjects and has a consequential value for health and well-being of elderly institutionalized patients.

Aged↗