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Biomedical subjects

W Dick

Publications and source records attributed to W Dick.

At least 19 recordsLinked to original sources
PubMed2006

Is fall prevention by vitamin D mediated by a change in postural or dynamic balance?

INTRODUCTION: The objectives were:(1) to validate a quantitative balance assessment method for fall risk prediction; (2) to investigate whether the effect of vitamin D and calcium on the risk of falling is mediated through postural or dynamic balance, as assessed by this method. MATERIALS AND METHODS: A secondary analysis of a double blind randomized controlled trial was employed, which included 64 institutionalized elderly women with complete balance assessment (age range: 65-97; mean 25-hydroxyvitamin D levels: 16.4 ng/ml (SD +/-9.9). Participants received 1,200 mg calcium plus 800 IU cholecalciferol (n=33) or 1,200 mg calcium (n=31) per day over a 3-month treatment period. Using an electronic device attached to the lower back of the participant, balance was assessed as the degree of trunk angular displacement and angular velocity during a postural task (standing on two legs, eyes open, for 20 s) and a dynamic task (get up from a standard height chair with arm rests, sit down and then stand up again and remain standing). RESULTS: It was found that both postural and dynamic balance independently and significantly predicted the rate of falling within the 3-month follow-up. Vitamin D plus calcium reduced the rate of falls by 60% [relative risk (RR)=0.40; 95% CI: 0.17, 0.94] if compared with calcium alone. Once postural and dynamic balance were added to the regression analysis, they both attenuated the effect of vitamin D plus calcium on the rate of falls. For postural balance, the RR changed by 22% from 0.40 to 0.62 if angular displacement was added to the model, and by 9% from 0.40 to 0.49 if angular velocity was added. For dynamic balance, it changed by 1% from 0.40 to 0.41 if angular displacement was added, and by 14% from 0.40 to 0.54 if angular velocity was added. DISCUSSION: Thus, balance assessment using trunk angular displacement is a valid method for the prediction of falls in older women. Of the observed 60% reduction in the rate of falls by vitamin D plus calcium supplementation compared with calcium alone, up to 22% of the treatment effect was explained by a change in postural balance and up to 14% by dynamic balance.

Accidental Falls↗
PubMed2006

[Muscle biomechanics in total ankle replacement].

The purpose of this orthopaedic-biomechanical study was to evaluate the muscle function in total ankle replacement (TAR) patients 1 year after surgery. Ten patients underwent a combined clinical and muscle biomechanical assessment prior to implantation and at the 1-year follow-up. Pain score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle score, ankle range of motion (ROM), and calf circumference difference between the affected leg and contralateral healthy leg were assessed. Biomechanically, isometric maximal voluntary torque for ankle dorsiflexion and plantar flexion was measured simultaneously with surface electromyography of four lower leg muscles. At follow-up, a significant improvement of the pain score (from 6.7 to 0.8 points), AOFAS ankle score (from 35.6 to 92.3 points), and ROM could be shown. Not significantly, the mean calf circumference difference between legs decreased from 2.2 to 1.4 cm. However, a significant increase was seen in the mean dorsiflexion (from 17.0 to 25.8 Nm) and plantar flexion torque (15.7 to 24.6 Nm) of the TAR-treated ankle. The mean EMG frequency content of the affected lower leg at TAR follow-up was lower than in the muscles of the contralateral healthy side. In contrast, the mean EMG intensity at TAR follow-up in side-comparison was statistically the same for all muscles. Ankle OA patients have better muscle function with TAR than under the arthritic condition, but they do not reach the normal level of the contralateral healthy leg 1 year after surgery.

Adult↗
PubMed2005

Amino-bisphosphonates in heterotopic ossification: first experience in five consecutive cases.

STUDY DESIGN: Retrospective, observational study in five consecutive cases. OBJECTIVES: The management of heterotopic ossification (HO), a frequent complication after spinal cord injury (SCI) and after orthopaedic surgery, is a therapeutic challenge with high recurrence rates of over 50%. Conflicting data were reported for Etidronate. The use of the more potent new generation of amino-bisphosphonates has been put forward in different inflammatory, dysmorphogenic bone disease. In order to try and halt the underlying dysfunctional bone metabolism we have studied the action of pamidronate in five consecutive high-risk patients with established HO of different etiology undergoing surgical removal. SETTING: University Hospital of Basel, Switzerland, Division of Endocrinology, Diabetology and Clinical Nutrition and the Department of Orthopedic Surgery. METHODS: In all five patients, ranging from 47 to 68 years of age, we used continuous pamidronate infusions perioperatively at a dosage of 120 mg in the first 12 h and subsequent reduction to 75-60-30-15 mg/12 h over a period of 10-14 days. RESULTS: None of these patients showed clinical, radiographical and laboratory signs of HO recurrence or new forming HO in the follow-up 5-54 month after surgery. Potential side effects of high-dose bisphosphonate therapy such as osteoporosis and osteomalacia were not reported in any case. CONCLUSION: We postulate that pamidronate might have pronounced beneficial effects in high-risk patients with established HO undergoing excision surgery. Since the therapeutic window of amino-bisphosphonates has not yet been defined and the minimal necessary doses for preventing new HO are unknown, further studies are encouraged to confirm our findings and to identify the necessary dosage and duration of treatment and to pinpoint, which patients will benefit most from this treatment.

Aged↗
PubMed2005

Improvements in balance after total hip replacement.

We have investigated whether control of balance is improved during stance and gait and sit-to-stand tasks after unilateral total hip replacement undertaken for osteoarthritis of the hip. We examined 25 patients with a mean age of 67 years (sd 6.2) before and at four and 12 months after surgery and compared the findings with those of 50 healthy age-matched control subjects. For all tasks, balance was quantified using angular measurements of movement of the trunk. Before surgery, control of balance during gait and sit-to-stand tasks was abnormal in patients with severe osteoarthritis of the hip, while balance during stance was similar to that of the healthy control group. After total hip replacement, there was a progressive improvement at four and 12 months for most gait and sit-to-stand tasks and in the time needed to complete them. By 12 months, the values approached those of the control group. However, trunk pitch (forwards-backwards) and roll (side-to-side) velocities were less stable (greater than the control) when walking over barriers as was roll for the sit-to-stand task, indicative of a residual deficit of balance. Our data suggest that patients with symptomatic osteoarthritis of the hip have marked deficits of balance in gait tasks, which may explain the increased risk of falling which has been reported in some epidemiological studies. However, total hip replacement may help these patients to regain almost normal control of balance for some gait tasks, as we found in this study. Despite the improvement in most components of balance, however, the deficit in the control of trunk velocity during gait suggests that a cautious follow-up is required after total hip replacement regarding the risk of a fall, especially in the elderly.

Accidental Falls↗
PubMed2005

A computer touch-screen version of the North American Spine Society outcome assessment instrument for the lumbar spine.

We validated the North American Spine Society (NASS) outcome-assessment instrument for the lumbar spine in a computerised touch-screen format and assessed patients' acceptance, taking into account previous computer experience, age and gender. Fifty consecutive patients with symptomatic and radiologically-proven degenerative disease of the lumbar spine completed both the hard copy (paper) and the computerised versions of the NASS questionnaire. Statistical analysis showed high agreement between the paper and the touch-screen computer format for both subscales (intraclass correlation coefficient 0.94, 95% confidence interval (0.90 to 0.97)) independent of computer experience, age and gender. In total, 55% of patients stated that the computer format was easier to use and 66% preferred it to the paper version (p < 0.0001 among subjects expressing a preference). Our data indicate that the touch-screen format is comparable to the paper form. It may improve follow-up in clinical practice and research by meeting patients' preferences and minimising administrative work.

Adolescent↗
PubMed2004

[Prehospital emergency airway management procedures. Success rates and complications].

BACKGROUND: Oxygenation and ventilation as well as prevention of aspiration are of vital importance for emergency patients. Prehospital airway management is not comparable to clinical anaesthesia. However, prehospital data of the occurrence of potential life-threatening complications and less severe adverse events of airway management procedures by emergency physicians are not yet available. METHODS: All airway management procedures predominantly performed by emergency physicians over a period of 36 months were recorded prospectively. RESULTS: Data of 598 consecutive patients were collected, in all patients prehospital airway management could be accomplished successfully. Of the patients 98.5% were successfully intubated endotracheally with a maximum of 3 attempts, 84.6% of patients were intubated at the first attempt, and in 9 patients other techniques such as the Combitube were required. In more than 80% of procedures, no complications or adverse events were recorded and potentially life-threatening complications occurred in 9% of patients only. CONCLUSIONS: Prehospital airway management by emergency physicians experienced in anaesthesia is associated with low complication and high success rates.

Anesthesiology↗
PubMed2004

Vitamin D receptor expression in human muscle tissue decreases with age.

UNLABELLED: Intracellular 1,25-dihydroxyvitamin D receptor (VDR) is expressed in human skeletal muscle tissue. However, it is unknown whether VDR expression in vivo is related to age or vitamin D status, or whether VDR expression differs between skeletal muscle groups. INTRODUCTION: We investigated these factors and their relation to 1,25-dihydroxyvitamin D receptor (VDR) expression in freshly removed human muscle tissue. MATERIALS AND METHODS: We investigated biopsy specimens of the gluteus medius taken at surgery from 20 female patients undergoing total hip arthroplasty (mean age, 71.6 +/- 14.5; 72% > 65 years) and biopsy specimens of the transversospinalis muscle taken at surgery from 12 female patients with spinal operations (mean age, 55.2 +/- 19.6; 28% > 65 years). The specimens were obtained by immunohistological staining of the VDR using a monoclonal rat antibody to the VDR (Clone no. 9A7). Quantitative VDR expression (number of VDR positive nuclei) was assessed by counting 500 nuclei per specimen and person. Serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were assessed at day of admission to surgery. RESULTS: All muscle biopsy specimens stained positive for VDR. In the univariate analyses, increased age was associated with decreased VDR expression (r = 0.5: p = 0.004), whereas there were no significant correlations between VDR expression and 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D levels. VDR expression did not differ between patients with hip and spinal surgery. In the multivariate analysis, older age was a significant predictor of decreased VDR expression after controlling biopsy location (gluteus medius or the transversospinalis muscle), and 25-hydroxyvitamin D levels (linear regression analysis: beta-estimate = -2.56; p = 0.047). CONCLUSIONS: Intranuclear immunostaining of the VDR was present in muscle biopsy specimens of all orthopedic patients. Older age was significantly associated with decreased VDR expression, independent of biopsy location and serum 25-hydroxyvitamin D levels.

Adult↗
PubMed2003

[Value of sonography to monitor the course of Achilles tendon rupture after treatment--comparison of conservative therapy, percutaneous tendon adaptation, and open suture].

In this prospective study,73 patients (with an average age of 36 years) were examined by ultrasound to compare the results of open Achilles tendon surgery, percutaneous tendon adaptation, and conservative treatment. Once the accident reports had been collected, all of the patients presented themselves at the Sportklinik Stuttgart at intervals of 4, 8, 12, 26 weeks, and approx. 2.5 years after the accident. During the course of these examinations, the thickness and structure of the tendon was quantified via ultrasound and the quality by clinical examination. The results of the ultrasonic quantification of the healing process appeared to be similar in all patients. On the day of the accident the thickness of the tendon was 9.3 mm. Four weeks later a remarkable regeneration could be seen in all patients (12.0 mm), which reached a maximum (16.7 mm) after 26 weeks. By the end of the study, however, the result was a scarred and thickened tendon of 11.5 mm. The comparison of the ultrasound results and the clinical examination after 26 weeks and 2.5 years showed no correlation between the value of the echo structure and functionality of the tendon, and the comparison between the different therapy groups showed no significant difference in the healing process either. In conclusion, ultrasound examination is able to provide information concerning the stage of the healing process. The quality of the healing and healed Achilles tendon and the relationship to their function cannot be studied with ultrasound, and this is not influenced by the choice of therapy.

Achilles Tendon↗
PubMed2003

[Effect of vitamin D on muscle strength and relevance in regard to osteoporosis prevention].

A successful prevention strategy for fractures in the elderly should not be limited to an improvement in bone mineral density. Equally important is the prevention of falls. Thus, 90% of fractures in the elderly are associated with a fall and 30% of all ambulatory, and 50% of institutionalized elderly age 65 years and older fall at least once a year. Fall incidence increases 10% per decade thereafter. According to recent studies, vitamin D and calcium supplementation may be a promising treatment strategy targeting both bone mineral density, as well as muscle strength and the risk of falling. The protective effect of vitamin D on fractures has been attributed to the established moderate benefit of vitamin D on bone mineral density. However, an alternative explanation might be that vitamin D affects factors directly related to muscle strength, thus, reducing fracture risk through improved function and fall prevention, in addition to its benefits on calcium homeostasis.

Accidental Falls↗
PubMed2003

[Patient's emotional satisfaction with anaesthetic care].

OBJECTIVE: The evaluation of services by patients is an integral part of continuous quality improvement in anaesthesia. Patient satisfaction is affected by various objective and subjective variables. Individual experiences, impressions and needs represent an important part of overall patient satisfaction. METHODS: Data of 519 patients were collected in a standardised anonymous questionnaire independent of the post-anaesthetic visit. RESULTS: Anaesthesia staff appeared to be friendly to 97 % of patients asked, 95 % of patients wanted to be treated by the same staff in case of another anaesthesia, nearly 87 % felt relaxed and satisfied after anaesthesia. Up to 26 % of patients felt tense after pre-anaesthetic visit and 38 % before anaesthesia, 35 % felt that waiting before operation was endless and 20 % complained about loss of humaneness because of technical equipment and monitoring. Significant differences could be found between specific groups of patients: Older and male patients were in all more satisfied compared to younger and female patients, patients after regional anaesthesia were more satisfied compared to ones after general anaesthesia. CONCLUSION: The inquiry of subjective patient impressions can be performed in anaesthesia departments without much effort. The results help to identify and avoid psycho-vegetative stressing situations and to improve patient satisfaction with anaesthesia.

Adult↗
PubMed2002

[Effective in vivo radiation dose with image reconstruction controlled pedicle instrumentation vs. CT-based navigation].

UNLABELLED: There is a rapid increase of computer-assisted surgery (CAS) in the spine for insertion of pedicle screws. In contrast to the traditional technique using fluoroscopy, CT is the primary source for surgical navigation systems. PURPOSE OF THE STUDY: To compare organ and effective doses of fluoroscopy-controlled versus computer-assisted pedicle screw insertion under the aspect of risk reduction and number needed to treat. MATERIALS AND METHODS: In 20 consecutive cases of traditional pedicle screw instrumentation under fluoroscopic control the effective doses were recorded in vivo and the organ doses then calculated. Simulating a spiral CT necessary for the 3-D-model for navigation we defined a spiral CT protocol for the instrumented levels and calculated organ and effective doses from Monte Carlo Results from CT examinations. RESULTS: Organ doses were clearly higher for the CT model than in any of the fluoroscopic procedures in vivo. The mean effective dose for the CT model was fifteen times higher than the fluoroscopic dose: 7.27 mSv versus 0.48 mSv. CONCLUSIONS: In experienced hands open pedicle screw insertion in the thoracic and lumbar spine using fluoroscopy-control requires a fifteen times lower radiation dose than do CT scans necessary for computer-assisted surgery. Regarding the published small percentage of neurological complications in traditional screw insertion technique the use of computer-assisted surgery in pedicle screw insertion using CT scan should be limited to carefully chosen indications. The development of navigation systems based on other data sources than CT should be encouraged.

Adolescent↗
PubMed2002

[Spondylolysis and spondylolisthesis during growth].

Spondylolysis and Spondylolisthesis present with typical age and activity-related issues: in newborns the pars interarticularis is always intact. Only bipedal ambulators develop spondylolysis, mostly during early childhood. Corresponding to the mechanical etiology, the incidence of spondylolysis is higher in athletes who repeatedly have to hyperextent and rotate their lumbar spine for example gymnasts, javelin throwers etc. Spondylolysis is one of the most frequent diagnosis among adolescents with lumbar back pain. However, most of the people with an interrupted Pars interarticularis (about 6% of the population) never become symptomatic or if they do, they respond very well to conservative treatment (adaptation of physical activity, active physical therapy and bracing). If pain persists in combination with an intact intervertebral disc of the slipped segment, we recommend a direct repair of the Pars interarticularis instead of an intersegmental fusion. Patients with low grade Spondylolisthesis (Meyerding I, II) require repeated radiological follow-up during growth because of the inherent risk of slip progression. If a slip of more than 50% is detected before the end of growth, operative treatment is indicated. High grade olisthesis (Meyerding III, IV) leads to anterior shift of the whole trunk, kyphosis of the slipped vertebra with subsequent compensatory lumbar hyperlordosis and flattening of the thoracic spine. Pelvic flexion is clinically evident. Reduction of the slipped and kyphotic vertebra with correction of the spinal, sacral and pelvic profile is recommended and preferable to simple fusion in situ.

Adolescent↗
PubMed2001

Specific growth factors during the expansion and redifferentiation of adult human articular chondrocytes enhance chondrogenesis and cartilaginous tissue formation in vitro.

Adult human articular chondrocytes were expanded in a medium with 10% serum (CTR) or further supplemented with different mitogens (i.e., EGF, PDGFbb, FGF-2, TGF beta 1, or FGF-2/TGF beta 1). Cells were then induced to redifferentiate in 3D pellets using serum-supplemented medium (SSM), serum-free medium (SFM), or SFM supplemented with factors inducing differentiation of chondroprogenitor cells (i.e., TGF beta 1 and/or dexamethasone). All factors tested during expansion enhanced chondrocyte proliferation and dedifferentiation, as assessed by the mRNA ratios of collagen type II to type I (CII/CI) and aggrecan to versican (Agg/Ver), using real-time PCR. FGF-2/TGF beta 1-expanded chondrocytes displayed the lowest doubling times, CII/CI and Agg/Ver ratios, averaging, respectively, 50, 0.2 and 15% of CTR-expanded cells. Redifferentiation in pellets was more efficient in SFM than SSM only for EGF-, PDGFbb- or FGF-2-expanded chondrocytes. Upon supplementation of SFM with TGF beta and dexamethasone (SFM TD), CII/CI ratios decreased 4.4-fold for EGF- and PDGFbb-expanded chondrocytes, but increased 96-fold for FGF-2/TGF beta 1-expanded cells. Chondrocytes expanded with FGF-2/TGF beta 1 and redifferentiated in SFM TD expressed the largest mRNA amounts of CII and aggrecan and generated cartilaginous tissues with the highest accumulation of glycosaminoglycans and collagen type II. Our results provide evidence that growth factors during chondrocyte expansion not only influence cell proliferation and differentiation, but also the cell potential to redifferentiate and respond to regulatory molecules upon transfer into a 3D environment.

Adult↗