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Biomedical subjects

P G Knipschild

Publications and source records attributed to P G Knipschild.

At least 19 recordsLinked to original sources
PubMed1998

Low-level laser therapy in ankle sprains: a randomized clinical trial.

OBJECTIVE: To test the efficacy of low-level laser therapy on lateral ankle sprains as an addition to a standardized treatment regimen, a trial was conducted in which high-dose laser (5J/cm2), low-dose laser (0.5J/cm2), and placebo laser therapy (0J/cm2) at skin level were compared. DESIGN: Randomized, double-blind, controlled clinical trial with a follow-up of 1 year. Patients, therapists, assessors, and analysts were blinded to the assigned treatment. SETTING: An ambulatory care setting. PATIENTS: After informed consent and verification of exclusion criteria, 217 patients with acute lateral ankle sprains were randomized to three groups from September 1, 1993, through December 31, 1995. INTERVENTIONS: Twelve treatments of 904nm laser therapy in 4 weeks as an adjunct to a standardized treatment regimen of 4 weeks of brace therapy combined with standardized home exercises and advice. The laser therapy device used was a 904nm Ga-As laser, with 25-watt peak power and 5,000 or 500Hz frequency, a pulse duration of 200nsec, and an irradiated area of 1cm2. PRIMARY OUTCOME MEASURES: Pain and function as reported by the patient. RESULTS: Intention-to-treat analysis of the short-term results showed no statistically significant difference on the primary outcome measure, pain (p = .41), although the placebo group showed slightly less pain. Function was significantly better in the placebo group at 10 days (p = .01) and 14 days (p = .03) after randomization. The placebo group also performed significantly better on days of sick leave (p = .02) and at some points for hindrance in activities in daily life and pressure pain, as well as subjective recovery (p = .05). Intention-to-treat analysis showed that total days of absenteeism from work and sports were remarkably lower in the placebo group than in the laser groups, ranging from 3.7 to 5.3 and 6 to 8 days, respectively. The total number of relapses at 1 year in the low-dose laser group (n = 22) was significantly higher (p = .04) than in the other two groups (high laser, n = 13; placebo, n = 13). Subgroup analysis to correct for possible confounders did not alter these findings. CONCLUSIONS: Neither high- nor low-dose laser therapy is effective in the treatment of lateral ankle sprains.

Adult↗
PubMed1998

Balneotherapy and quality assessment: interobserver reliability of the Maastricht criteria list and the need for blinded quality assessment.

This study investigates aspects of the reliability of the Maastricht criteria list for quality assessment in systematic reviews, and whether blinded reviewing is necessary to prevent review bias. We used the data set of 12 articles from a systematic review concerning the efficacy of balneotherapy in patients with arthritis. Twenty reviewers participated of which two reviewers, who have been involved in developing the Maastricht criteria list, acted as reference standard. Half of all assessments were performed blindly. A high level of agreement was found between the reviewers and a high level of correlation with the reference standard. The quality scores between the blinded and unblinded assessment did not differ much. Based on the results we conclude that the Maastricht criteria list is a reliable instrument in quality assessment of clinical trials. Within the limits of this study we found no evidence that blinding is necessary to prevent review bias.

Arthritis↗
PubMed1998

Optimization of placebos for double-blind clinical trials. Experience with a phytopharmaceutical.

The maintenance of double-blind conditions in placebo-controlled trials depends on the quality of the placebo preparation. The placebo should match the active substance-containing preparation as closely as possible, but it must not contain any substances that might themselves be pharmacologically active. Active substances characterized by a particular colour, taste, smell or other easily perceptible properties constitute a challenge to researchers. The way of developing a placebo that matches a phytopharmaceutical to a satisfactory extent is described and discussed.

Aged↗
PubMed1997

Efficacy of traction for nonspecific low back pain. 12-week and 6-month results of a randomized clinical trial.

STUDY DESIGN: A randomized clinical trial. OBJECTIVES: To assess the efficacy of motorized continuous traction for low back pain. SUMMARY OF BACKGROUND DATA: The available studies on the efficacy of lumbar traction do not allow clear conclusions because of severe methodologic flaws. The current trial aimed to overcome these shortcomings. METHODS: Patients with at least 6 weeks of nonspecific low back pain were selected. High-dose traction was compared with sham (or low-dose) traction. Sham traction was given with a specially developed brace that becomes tighter in the back during traction. This was experienced as if real traction were exerted. The patients and the outcome assessor were unaware of treatment allocation. Outcome measures were: patient's global perceived effect, severity of main complaints, functional status, pain, range of motion, work absence, and medical treatment. Results for the outcome measures at 12 weeks and 6 months after randomization are presented. RESULTS: One hundred and fifty-one patients were randomly allocated to one of the two treatment methods. Intention-to-treat analysis of the 12-week and 6-month results showed no statistically significant differences between the groups on all outcome measures: all 95% confidence intervals included the value zero. The number of patients lost to follow-up study was very low. Other analyses showed the same results. CONCLUSIONS: Most common flaws of earlier studies on traction therapy could be overcome. This trial did not support the claim that traction is efficacious for patients with low back pain.

Adult↗
PubMed1997

Reliability of lumbar spine radiograph reading by chiropractors.

STUDY DESIGN: An intraobserver and interobserver study on the reproducibility of data was performed. OBJECTIVES: This study investigates the variability in the interpretation of lumbar spine radiographs by chiropractors working in private practice. SUMMARY OF BACKGROUND DATA: In chiropractic practice radiographs are used often, but this use is currently under debate. Therefore, there is a need for further study of the value of diagnoses made by radiographs by chiropractors. An acceptable intra- and interobserver agreement in radiograph reading is a prerequisite for a useful application of radiographs as a diagnostic tool in daily practice and in research. METHODS: Four chiropractors read 100 blinded sets of standard, erect anteroposterior and lateral lumbar radiographs independently. The same set was read in two separate sessions with a 2-month interval. The first session revealed the interobserver agreement. The comparison of the ratings by the same assessor in the two sessions indicated the intraobserver agreement. The assessors used a specially developed criteria list with emphasis on "nonspecific" radiographic findings. The prevalence of some important categories was increased artificially. Agreement was expressed in percentage agreement and generalized kappa, combining the results of all four assessors. RESULTS: Most kappas ranged from 0.40 to 0.75, representing fair to good agreement. In general, intraobserver agreement was better than interobserver agreement. The low kappas that were found may be explained partially by the high-agreement-low-kappa paradox as a result of a low prevalence. CONCLUSION: The kappas and percentage agreement were acceptable, although not excellent. These results will be beneficial for future research on the value of radiograph diagnosis of nonspecific findings for delivery of safe and effective chiropractic therapy.

Adult↗
PubMed1997

The prognosis of ankle sprains.

We developed a new diagnostic tool for predicting the severity of ankle sprains just after injury. Since hard data obtained by diagnostic imaging techniques are still imperfect, we decided to use data from individual medical history and signs and symptoms that are part of the admission routine. During a three month-period data were collected on thirty-five patients with lateral ankle sprains who visited the first aid department of the University Hospital of Maastricht. Assessments took place at admission and at two and four weeks after injury. Assessors were the first-aid physician, a physiotherapist and the patient. Dependent variables were healed ankle in two and four weeks. Predicting variables were the data obtained at admission by the physician, the physiotherapist and the patient. The ability to predict outcome after two and four weeks was determined in a bivariate analysis, followed by logistic modelling. Accurate prediction of recovery time at admission appeared to be possible. Best two weeks predictor was the modified function score, an accuracy of 97% was achieved. Four weeks prediction was most accurate when function score was used together with the report mark from the doctor and the palpation score (accuracy of 81%).

Activities of Daily Living↗
PubMed1997

Taking baths: the efficacy of balneotherapy in patients with arthritis. A systematic review.

OBJECTIVE: To review English, French, German, and Dutch language studies of the effectiveness of balneotherapy. Balneotherapy (hydrotherapy or spa therapy) is one of the oldest forms of therapy for patients with arthritis. One of the aims of balneotherapy is to relieve pain. METHODS: We performed a systematic review that included randomized and nonrandomized studies. Quality scores of the studies were determined using a criteria list. RESULTS: Most studies report positive findings, but all studies showed methodological flaws. A quality of life measurement was never reported as an outcome measure. None of the randomized clinical trials included intention-to-treat analysis or comparison of effects between groups. CONCLUSION: Because of the methodological flaws a conclusion about the efficacy of balneotherapy cannot be provided from studies we reviewed. We conclude that most flaws found could be avoidable in future research.

Arthritis↗
PubMed1996

Complications of spinal manipulation: a comprehensive review of the literature.

BACKGROUND: Spinal manipulative therapy (SMT) is a frequently applied therapy for back and neck pain. Serious complications of SMT are presented primarily in case reports. Many patients seen by physicians also seek care from therapists applying manipulative techniques. Therefore, background information on the risks of SMT is essential for physicians. METHODS: Relevant case reports, surveys, and review articles were identified using a comprehensive search of online and bibliographical databases. For every case, a record was made of first author, publication year, country, age and sex of the patient, background of the manipulator, preexisting conditions, type of complication, and course of the complication. Based on case reports and surveys, an estimation was made of the risk for the most frequently reported complications: vertebrobasilar accidents (VBAs) and cauda equina syndrome (CES). RESULTS: We derived 295 complications of spinal manipulations from the literature: 165 VBAs; 61 cases with disc herniation or progression to CES; 13 cerebral complications other than VBAs; and 56 other types of complications. The average age of patients with VBA was 38 years. Vertebrobasilar accidents occur mainly after a cervical manipulation with a rotatory component. Estimates of VBA range from 1 per 20,000 patients to 1 per 1 million cervical manipulations. The incidence of CES is estimated to be less that 1 per 1 million treatments. CONCLUSIONS: It is difficult to estimate the incidence of SMT complications, as they are probably underreported in the literature. Most non-VBA complications can be prevented by excluding patients with contraindications for SMT. Patients who develop complications such as CES should be treated as soon as possible. VBAs, however, are difficult to prevent and treat. Referral for SMT should not be made to practitioners applying rotatory cervical manipulation. Information about the risk of VBA should be included in an informed consent procedure for cervical manipulation with thrust techniques.

Back Pain↗
PubMed1995

The relationship between methodological quality and conclusions in reviews of spinal manipulation.

OBJECTIVE: To study the relationship between the methodological quality and other characteristics of reviews of spinal manipulation for low back pain on the one hand and the reviewers' conclusions on the effectiveness of manipulation on the other hand. DATA SOURCES: Reviews identified by MEDLINE search, citation tracking, library search, and correspondence with experts. STUDY SELECTION: English- or Dutch-language reviews published up to 1993 dealing with spinal manipulation for low back pain that include at least two randomized clinical trials (RCTs). DATA EXTRACTION: Methodological quality was assessed using a standardized criteria list applied independently by two assessors (range, 0% to 100%). Other extracted characteristics were the comprehensiveness of the search, selective citation of studies, language, inclusion of non-RCTs, type of publication, reviewers' professional backgrounds, and publication in a spinal manipulation journal or book. The reviewers' conclusions were classified as negative, neutral, or positive. DATA SYNTHESIS: A total of 51 reviews were assessed, 17 of which were neutral and 34 positive. The methodological quality was low, with a median score of 23%. Nine of the 10 methodologically best reviews were positive. Other factors associated with a positive reviewers' conclusion were review of spinal manipulation only, inclusion of a spinal manipulator in the review team, and a comprehensive literature search. CONCLUSIONS: The majority of the reviews concluded that spinal manipulation is an effective treatment for low back pain. Although, in particular, the reviews with a relatively high methodological quality had a positive conclusion, strong conclusions were precluded by the overall low quality of the reviews. More empirical research on the review methods applied to other therapies in other professional fields is needed to further explore our findings about the factors related to a positive reviewers' conclusion.

Humans↗
PubMed1995

Efficacy of traction for non-specific low back pain: a randomised clinical trial.

Previous trials to assess the efficacy of lumbar traction for back pain have been methodologically flawed. To avoid these shortcomings, we conducted a randomised controlled trial in which high-dose traction was compared with sham traction. The sham traction was given with a specially developed brace that tightens in the back during traction. To the patient, the experience is that of traction. The patients and outcome assessor were blinded for the assigned treatment. 151 patients with at least six weeks of non-specific low back pain were randomised. Intention to treat analysis showed no differences between the groups on all outcome measures (patients' global perceived effect, severity of main complaints, functional status and pain); all 95% confidence intervals included the value zero. The number of withdrawals from treatment, loss to follow-up, and protocol deviations was low. Consequently, the per-protocol analysis showed results similar to the intention to treat analysis. Subgroup analyses did not show any group for which traction might seem promising. Our data do not support the claim that traction is effective for patients with low back pain.

Adult↗
PubMed1995

Measuring the functional status of patients with low back pain. Assessment of the quality of four disease-specific questionnaires.

STUDY DESIGN: This study was a literature review of the quality of four disease-specific functional status questionnaires for patients with low back pain: Oswestry; Million; Roland; and Waddell disability questionnaire. OBJECTIVES: The questionnaires were evaluated in terms of general description, scale structure, reliability, validity, responsiveness, and clinical research applications. SUMMARY OF BACKGROUND DATA: Functional status is an outcome of great interest for clinical trials of low back pain. METHODS: A computer-aided search was conducted of articles published between 1981 and 1993 and references given in selected relevant publications. Articles were selected if at least one of the four functional status questionnaires was used or if the authors gave relevant information about the methodology of these questionnaires. RESULTS: There was not enough information available about the criteria of item selection used for the development of the questionnaires. The test-retest reproducibility of the questionnaires seemed satisfactory. The Oswestry and Roland disability questionnaires have been used and evaluated more frequently than the Million and Waddell. Therefore, we can be more certain about the validity and responsiveness of the former pair of questionnaires. CONCLUSION: In the absence of a gold standard, direct comparisons of evaluative functional status questionnaires in a single patient group are needed. Through direct comparisons, comparative validity and responsiveness can be assessed. Functional status measures are not currently used in many settings in which they would be valuable. It is important to encourage their wider use in clinical trials. Additional research is needed to compare and improve the existing questionnaires.

Activities of Daily Living↗
PubMed1995

Randomized clinical trial of ascorbic acid in the treatment of pressure ulcers.

The objective of this study was to assess the effects of ascorbic acid supplementation, 500 mg twice daily in the treatment of pressure ulcers as an adjunct to standardized treatment. The design consisted of a multicenter blinded randomized trial. The control group received 10 mg of ascorbic acid twice daily. Patients from 11 nursing homes and 1 hospital participated. Main outcome measures included wound survival, healing rates of wound surfaces, and clinimetric changes over 12 weeks. Eighty-eight patients were randomized. Intention-to-treat analysis showed that the wound closure probability per unit time (i.e., the closure rate) was not higher in the intervention group than in the control group (Cox hazard ratio of 0.78 [90% precision interval, 0.44-1.39]). Mean absolute healing rates were 0.21 and 0.27 cm2/week in the intervention and control group, respectively (PI of the adjusted difference: -0.17 to 0.13). Relative healing rates and healing velocities did not show favorable results of ascorbic acid supplementation, either. A panel scored slides of the ulcers with a report mark between 1 (bad) and 10 (excellent). The improvement was 0.45 and 0.72 points per week in the intervention and control group, respectively (PI of the adjusted difference: -0.50 to 0.20). With another clinimetric index we could not show any differences, either. These data do not support the idea that ascorbic acid supplementation (500 vs. 10 mg twice daily) speeds up the healing of pressure ulcers.

Ascorbic Acid↗
PubMed1994

The role of cigarette smoking in the etiology of cervical dysplasia.

We evaluated the effect of smoking on the risk of cervical dysplasia in a large case-control study, obtaining smoking information from a mail questionnaire. We observed higher risks with increasing numbers of cigarettes smoked, but not with longer duration of smoking. The risk for ex-smokers was between those of current smokers and nonsmokers and was lower for women who had stopped more than 10 years ago than for those who had quit more recently. Starting to smoke at an early age did not increase the risk of cervical dysplasia.

Adult↗
PubMed1993

A randomized trial about the perceived informativeness of new empirical evidence. Does beta-carotene prevent (cervical) cancer?

The perceived informativeness of a publication can be assessed by measuring the change in belief it induces among the scientific public, regarding a certain hypothesis. In a randomized trial, we studied the effect of empirical evidence from a clinical experiment and a case-control study on the hypothesis that beta-carotene protects against (cervical) cancer. The study population consisted of first authors of recently published patient-oriented research papers. They received an abstract of the clinical experiment, of the case-control study, or a "placebo" abstract. The latter was used to assess the specific effect of the empirical evidence in the two real studies. The change in belief in the hypotheses was expressed as a likelihood ratio (LR). All three abstracts led to a decrease in belief in the hypothesis. The median LRs of the abstracts of the experiment, case-control study and "placebo" were 0.33, 0.45, 0.75 respectively. This paper shows that the belief in a certain hypothesis is influenced by the quality of empirical evidence in a study. The magnitude of change induced by the experimental and case-control abstract had the anticipated order, but the change in belief induced by the "placebo" abstract was larger than we had expected. Reasons for this may be the concise information in the abstract and the variable methodological training of the study population.

Anticarcinogenic Agents↗
PubMed1993

The role of sexual factors in the aetiology of cervical dysplasia.

The effect of sexual behavior on the risk for cervical dysplasia was evaluated in a case-control study. Cases (n = 257) had a histologically confirmed diagnosis of cervical dysplasia. Controls (n = 705) were sampled from the general population. A postal questionnaire was used to obtain information about, among other things, age at first sexual intercourse, number of sexual partners, current frequency of intercourse and contraceptive use. Information was also collected about other risk factors for cervical dysplasia, in order to adjust for possible confounding. We observed higher risks for cervical dysplasia (mild, moderate and severe) with increasing number of sexual partners. This effect appeared to be dependent on smoking behaviour. For women who reported more than six sexual partners, the adjusted odds ratio (aOR) was 9.1 (95% CI: 3.5-23.7) for non-smokers, and 26.4 (95% CI: 11.8-58.8) for women who smoked > or = 20 cigarettes per day. The effects of age at first sexual intercourse and current frequency of intercourse disappeared after adjustment for other risk factors. Use of oral contraceptives for > 10 years increased the risk (aOR = 2.3; 95% CI: 1.2-4.6). Thus, the number of sexual partners, especially in combination with smoking behaviour, appeared to be the most important risk factor for cervical dysplasia.

Adjuvants, Immunologic↗
PubMed1993

A randomized clinical trial of manual therapy and physiotherapy for persistent back and neck complaints: subgroup analysis and relationship between outcome measures.

OBJECTIVE: To study the efficacy of manual therapy and physiotherapy in subgroups of patients with persistent back and neck complaints. The second objective was to determine the correlation between three important outcome measures used in this trial. DESIGN: Randomized clinical trial (subgroup analysis). SETTING: Primary health care in the Netherlands. PATIENTS: Two hundred fifty-six patients with nonspecific back and neck complaints of at least 6 wk duration who had not received physiotherapy or manual therapy in the past 2 yr. INTERVENTIONS: At the discretion of the manual therapists, physiotherapists and general practitioners. Physiotherapy consisted of exercises, massage and physical therapy (heat, electrotherapy, ultrasound, shortwave diathermy). Manual therapy consisted of manipulation and mobilization of the spine. Treatment by the general practitioner consisted of drugs (e.g., analgesics), advice about posture, home exercises and (bed)rest. Placebo treatment consisted of detuned shortwave diathermy (10 min) and detuned ultrasound (10 min). MAIN OUTCOME MEASURES: Changes in severity of the main complaint and limitation of physical functioning measured on 10-point scales by a blinded research assistant and global perceived effect measured on a 6-point scale by the patients. RESULTS: Improvement in the main complaint was larger with manual therapy (4.3) than with physiotherapy (2.5) for patients with chronic conditions (duration complaint of 1 yr or longer). Also, improvement in the main complaint was larger with manual therapy (5.5) than with physiotherapy (4.0) for patients younger than 40 yr (both were measured after 12-mo follow-up). Labeling of patients by the treating manual therapists as "suitable" or "not suitable" for treatment with manual therapy did not predict differences in outcomes. Generally, there was a moderate to strong correlation between the three outcome measures, although a considerable number of patients gave a relatively low score for perceived benefit, while the research assistant gave a high improvement score for the main complaint and physical functioning. CONCLUSIONS: The subgroup analysis suggests better results of manual therapy compared to physiotherapy in chronic patients (duration of present complaints of 1 yr or longer) and in patients younger than 40 yr old). Differences for other subgroups were less clear. The explorative findings of these subgroup analyses have to be investigated in future research.

Adult↗
PubMed1992

Randomised clinical trial of manipulative therapy and physiotherapy for persistent back and neck complaints: results of one year follow up.

OBJECTIVE: To compare the effectiveness of manipulative therapy, physiotherapy, treatment by the general practitioner, and placebo therapy in patients with persistent non-specific back and neck complaints. DESIGN: Randomised clinical trial. SETTING: Primary health care in the Netherlands. PATIENTS: 256 patients with non-specific back and neck complaints of at least six weeks' duration who had not received physiotherapy or manipulative therapy in the past two years. INTERVENTIONS: At the discretion of the manipulative therapists, physiotherapists, and general practitioners. Physiotherapy consisted of exercises, massage, and physical therapy (heat, electrotherapy, ultrasound, shortwave diathermy). Manipulative therapy consisted of manipulation and mobilisation of the spine. Treatment by general practitioners consisted of drugs (for example, analgesics), advice about posture, home exercises, and (bed)rest. Placebo treatment consisted of detuned shortwave diathermy (10 minutes) and detuned ultrasound (10 minutes). MAIN OUTCOME MEASURES: Changes in severity of the main complaint and limitation of physical functioning measured on 10 point scales by a blinded research assistant and global perceived effect measured on a 6 point scale by the patients. RESULTS: Many patients in the general practitioner and placebo groups received other treatment during follow up. Improvement in the main complaint was larger with manipulative therapy (4.5) than with physiotherapy (3.8) after 12 months' follow up (difference 0.9; 95% confidence interval 0.1 to 1.7). Manipulative therapy also gave larger improvements in physical functioning (difference 0.6; -0.1 to 1.3). The global perceived effect after six and 12 months' follow up was similar for both treatments. CONCLUSIONS: Manipulative therapy and physiotherapy are better than general practitioner and placebo treatment. Furthermore, manipulative therapy is slightly better than physiotherapy after 12 months.

Adult↗