Search

Objective: To develop a model to predict stroke-free survival and mortality over a multiyear time frame for a trial-excluded population of medically managed asymptomatic patients with significant carotid artery stenosis., Methods: We calibrated, validated, and applied a Monte Carlo microsimulation model. For calibration we adjusted general-population mortality and stroke risks to capture these risks specific to asymptomatic carotid stenosis patients. For validation, we compared model-predicted and actual stroke-free survival curves and stroke counts from a population of comparable patients. For application, the validated model predicted stroke-free survival for a hypothetical medically managed arm of a recent single-arm carotid revascularization trial., Results: For each month in the 60-month time frame, the model-predicted and actual calibration trial stroke-free survival curves were not statistically different (P > 0.62). In validation, the calibrated model's stroke-free survival curvematched the actual curve from an independent population; beyond 24 months, the model-predicted and actual curves were not statistically different (P > 0.32). We also compared model-predicted and actual number of strokes from the independent trial. The model predicted 187.25 strokes (95% confidence interval 161.49-213.01), while the actual number was 171.6, within 1.22 standard deviations of the simulated mean., Conclusions: Given the absence of medically managed populations in recent carotid stenosis trials, our model can estimate stroke-free survival and mortality data for these patients. The model may also estimate the effectiveness of novel medical and procedural therapies for stroke prevention. These effectiveness estimates can inform the development of policies, guidelines, or cost-effectiveness analyses when only single-arm trial data exist.

Although both beta-blockade (BB) and endoscopic variceal ligation (EVL) are used for primary prevention of variceal bleeding (VB) in patients with cirrhosis with moderate to large esophageal varices (EVs), the more cost-effective option is uncertain. We created a Markov decision model to compare BB and EVL in such patients, examining both cost-effectiveness (cost per life year [LY]) and cost-utility (cost per quality-adjusted life year [QALY]). Outcomes included cost per LY, cost per QALY, proportions of persons with VB, TIPS, and all-cause mortality. EVL and BB were compared using the incremental cost-effectiveness ratio (ICER) and incremental cost-utility ratio (ICUR). When considering only LYs, initial EVL exceeds the benchmark of 50,000 dollars/LY, with an ICER of 98,407 dollars. However, when quality of life (QoL) is considered, EVL is cost-effective compared to BB (ICUR of 25,548 dollars/QALY). In sensitivity analysis, EVL is cost-effective if the yearly risk of EV bleeding is > or = 0.26 (base case 0.15), the relative risk of bleeding on BB is > or = 0.69 (base case 0.58), or if the relative risk of bleeding with EVL is < 0.27 (base case 0.35). The ICUR favored EVL unless the relative risk of bleeding on BB is < 0.46, the relative risk of bleeding with EVL is > 0.46, or the time horizon is < or = 24 months. Whether EVL is "cost-effective" relative to BB therapy for primary prevention of EV bleeding depends on whether LYs or QALYs are considered. If only LYs are considered, then EVL is not cost-effective compared to BB therapy; however, if QoL is considered, then EVL is cost-effective.

Objective: To evaluate the cost-effectiveness of tamsulosin, doxazosin, or terazosin as initial treatments for moderate benign prostatic hyperplasia (BPH) over a 3-year time horizon from a health-system-payer perspective., Methods: A decision-analytic model is used to project the course of treatment at 6-month intervals over 3 years following initiation of therapy with tamsulosin, doxazosin, or terazosin. Treatment failure is defined as failure to attain and maintain a 25% improvement in the American Urological Association (AUA) symptom score from baseline. In the model, finasteride is added for patients who fail on their initial therapy and, in the event of finasteride treatment failure, patients progress to transurethral resection of the prostate (TURP) and, if needed, a second TURP. The ranges of values for treatment failure rates and clinical event cost parameters used in the decision model are derived from the literature. Only direct medical costs related to BPH and its treatment are included. Since 2 comparators are available generically (doxazosin and terazosin) drug acquisition costs are defined by the list prices at Drugstore.com. All costs are discounted by 3% per year. Effectiveness is measured as successful medical treatment without surgery over 3 years., Results: For base-case model parameters, discounted BPH-related total direct medical costs over 3 years are 4084 dollars, 4323 dollars, and 4695 dollars for generic terazosin, generic doxazosin, and tamsulosin, respectively. The model estimates a medical treatment success rate (no TURP) at 3 years of 72.3% for tamsulosin, compared with 68.2% for both terazosin and doxazosin. The incremental cost for tamsulosin versus terazosin is 610 dollars over 3 years, which yields an incremental cost-effectiveness ratio of 14,609 dollars per success. Generic doxazosin is dominated (higher cost but equal effectiveness compared with terazosin). Higher rates of twice-daily (or 2 units per day) dosing are associated with higher incremental cost-effectiveness ratios. The decision-model results also are sensitive to the estimated costs of TURP and hypotensive adverse events., Conclusion: As an initial medical therapy for moderate BPH, tamsulosin is more effective than generic terazosin or doxazosin, with an incremental cost of about 203 dollars per year (or about 17 dollars per month) over 3 years.

In this investigation, the static tensile strength of bone cement was quantified after mixing it in an open bowl or in a commercially available vacuum mixer and molding it under pressures consistent with values obtained by finger/digital application, as it is used in surgery. Pressure, held for a brief time span on cement in its lower viscosity state, has been demonstrated to increase penetration of the cement into bone. Clinically, bone cement is pressurized by digital pressure, specialized instruments, or by implant design. Specimens were cured under constant pressures of up to 100kPa, which is in the range reported for thumb pressurization of plugged proximal femurs and instrumented pressurization of acetabular sockets. The results showed that application of constant pressure during the polymerization of open bowl mixed bone cement significantly improved its mechanical properties. Application of 100kPa constant pressure to the open bowl mixed bone cement while it cured increased its ultimate strength to a value similar to vacuum mixed cement. Curing under pressure showed no significant effect on the tensile properties of vacuum mixed cement. Curing under pressure did not significantly reduce the size of the largest pores in the tensile specimens.

Objectives: The hemodynamic response to ss-blockers alone or with nitrates is highly predictive of efficacy in prevention of variceal bleeding. Hemodynamic monitoring (HDM) requires catheterization of the hepatic vein and measurement of the hepatic venous pressure gradient, the difference between wedged and free hepatic venous pressure. The aim of this study was to compare HDM with no HDM in patients considered for primary pharmacoprophylaxis of esophageal variceal bleeding., Methods: A decision model was constructed to compare HDM with no HDM in cirrhotic patients with moderate to large esophageal varices. Patients intolerant to beta-blocker therapy would undergo endoscopic variceal ligation; those with an inadequate hemodynamic response (HDR) to beta-blocker therapy could have nitrates added before ligation was considered. Variceal bleeding was treated with ligation, with transjugular intrahepatic portosystemic shunt (TIPS) reserved for refractory bleeding. Probabilities of treatment responses as well as risks of bleeding and mortality were based on published literature. Only direct costs were considered during the 5-yr time horizon. Outcomes were cost in United States dollars, survival length in life-years, and proportions of patients who experienced variceal bleeding, TIPS insertion, and mortality from any cause., Results: In the base case analysis, HDM was either cost-saving ($2,523 US dollars /life-year gained) or cost-effective (incremental cost-effectiveness ratio of $5,200 US dollars/life-year saved) compared with no HDM, depending on whether nitrates were added to beta-blocker therapy. HDM reduced variceal bleeding by nearly 60% and had a small effect on all-cause mortality. In the sensitivity analysis, HDM was sensitive to the time horizon, as it was not cost-effective for a time horizon of <22 months and was not cost-saving before 49 months. The cost-effectiveness of HDM was not sensitive to reasonable variation in the probability of HDR to beta-blocker therapy, risk of bleeding, risk reduction with pharmacotherapy, or to the costs of HDM, bleeding, ligation, or TIPS. Probabilistic sensitivity analysis indicated that HDM was more effective and less costly 100% and 57% of the time, respectively., Conclusions: Compared with the current standard of no HDM, measuring the hemodynamic response of primary pharmacoprophylaxis substantially reduces the number of bleeding episodes and is cost-effective or cost-saving over a wide range of sensitivity analyses. A randomized trial of HDM is needed to verify its efficacy in clinical practice.

Three days after liposuction of the lower abdomen, a 41-year-old woman was admitted for toxic shock-like syndrome with necrotising fasciitis and myositis, caused by Lancefield-group-A beta-haemolytic streptococci. The patient was treated by radical debridement of the skin, subcutis, fasciae and part of the pectoral muscle, plus antibiotics. Postoperatively she required artificial respiration for respiratory insufficiency. One week after the operation the wound was covered by transplantation of autologous skin. The patient survived, but was seriously disfigured. Necrotising fasciitis is a progressive soft-tissue infection, characterised by widespread necrosis of the superficial and deep fascia, often associated with severe systemic toxic reactions. Unless quickly recognised and aggressively treated, the course is often fatal. Due to the absence of cutaneous findings in the early stages, diagnosis is difficult. Important diagnostic aids are routine laboratory tests, contrast-MRI and a combination of the finger test and frozen-section biopsy. Treatment consists of early radical debridement, broad-spectrum antibiotics and supportive care. In a later stage, soft-tissue reconstruction with autografts or artificial skin grafts and skin transposition can be performed.

After proximal row carpectomy 11 patients were evaluated in the six ensuing years for pain relief, satisfaction, ranges of movement, grip and precision grip strength, and radiographic picture. The median follow-up period was 3.1 years (range 4 months to 6 years). They were operated on for scaphoid non-union with radiocarpal arthritis, late stage Kienböck's disease, chronic scapholunate dissociation and scapholunate advanced collapse wrist deformity. The mean disabilities of the arm, shoulder and hand (DASH) scoring list, which indicates the patient's degree of disability 28% (range 2%-64%) of maximum disability for the function and symptom score. Flexion, extension, and radial and ulnar deviation of the wrist improved to 47% (range 21%-76%), 67% (range 41%-81%), 39% (range 25%-55%), and 81% (range 44%-90%) of the opposite wrist. Mean grip strength, 70% (range 22%-117%) of the opposite site, while the three precision grips improved between 72% and 79%. A review of previous studies of proximal row carpectomy showed results comparable with those of our study. Compared with other treatments, it is a dependable, relatively-simple procedure that gives reliable relief of pain, preserves functional ranges of movement and grip strength, and allows most patients to return to work.

Children have specific emotional and physiological needs that are intensified when they sustain injuries that require surgery. Care of pediatric trauma patients includes the physiological considerations of airway management, hemodynamic stability, hypothermia, and physical size. Psychological considerations include enhancing coping skills, caring for children according to their developmental levels, and caring for family members. The perioperative nurse must be familiar with these pediatric trauma nursing principles to effectively meet the needs of children and their family members during times of trauma crisis.

A study was performed to determine the time-course of oxidative degradation and the extent to which the degradation proceeded through the bulk of ultra-high molecular weight polyethylene joint components that had been irradiated and stored on a shelf. Standardized cylindrical samples, taken from a single batch of extruded polyethylene, were cleaned, packaged, and sterilized according to protocols used for commercial joint-replacement components. After sterilization, the samples were stored in the packages for time-periods of one day to more than one year. At each interval studied, thin sections were cut as a function of depth into the bulk of the sample and were used to determine the density and the infrared spectra. Marked alterations in the density and the infrared spectra consistent with continuing oxidative degradation occurred throughout the year of storage on the shelf. The alterations were most severe near the surface of the samples.

The purpose of this study was to examine the mating surfaces of femoral heads and stems for evidence of corrosion, and to evaluate the quality of the taper lock of modular hip prostheses. Forty-eight implants with three different designs were evaluated. Group I (26 implants) had a cobalt alloy head and cobalt alloy stem. Group II (ten implants) had a cobalt alloy head and a titanium stem. Group III (12 implants) had a cobalt alloy head with a titanium stem that was coupled in the factory via a shrink fit. The implants were examined under light microscopy and scanning electron microscopy. In cases where the femoral head was still assembled to the stem, pull-off testing was performed using an MTS machine. The average failure load for the pull-off tests for each group of prostheses was as follows: Group I (nine implants) 3,003 N +/- 623 N; Group II (six implants) 4453 N +/- 570 N; and Group III (12 implants) 6859 N +/- 3525 N. The Group III implants required a significantly greater pull-off force than those in Group I (p = 0.002). There was no evidence of corrosion in Group I. In Group II, crevice corrosion was noted in one taper interface and there was fretting in two other tapers. No corrosion was noted in Group III. Improving the tolerances of the mating surfaces may be a key factor in preventing corrosion. This would not only increase the forces that are necessary to debond the matting surfaces, but also decrease corrosion by reducing micromotion and fluid at the taper interface.

Analytical studies of the stresses on and within ultra high molecular weight polyethylene joint components suggest that damage modes associated with polyethylene fatigue failure are caused by a combination of surface and subsurface crack propagation. Fatigue crack propagation tests under mixed mode loading conditions were conducted on center-cracked tension specimens machined from extruded blocks of sterilized polyethylene in an attempt to determine how fatigue cracks change direction in this material. Cyclic testing was performed using a sinusoidal wave form at a frequency of 5 Hz and an R-ratio (minimum load/maximum load) of 0.15. Specimens had the notch oriented perpendicular to the direction of applied load and at angles of 60 degrees and 45 degrees to the loading direction. Numerical analyses were used to interpret the experimental test and to predict the fatigue behavior of polyethylene under mixed mode conditions. It was found that all cracks eventually propagated horizontally, regardless of the initial angle of inclination of the notch to the direction of applied cyclic load. In fact, the extent of the curvilinear crack growth was quite limited. An effective range of cyclic stress intensity factor was calculated for correlation with the rate of crack growth. The results followed a Paris relation, with crack growth rate linearly related to a power of the range of stress intensity, for all three crack orientations. The numerical analyses adequately modeled the experimental fatigue crack growth results.

Observations of wear damage were performed on 12 retrieved porous coated anatomic (PCA) tibial components, all of which were removed because of excessive polyethylene wear. Density measurements of the remaining polyethylene were obtained as a function of depth from the surface of the components. Comparison to previous results from similar studies of total condylar type knee components and total hip acetabular components revealed distinct differences between the types and severity of damage, emphasizing the influence of design factors on the corresponding wear damage. These results confirm previous conclusions that nonconforming articulating surfaces on thin polyethylene components will be at higher risk of damage than more conforming surfaces on thicker components. It also appears that the high cyclic loads to which polyethylene implants are subjected in vivo are most responsible for the degradation in properties of the material near the articulating surface, although the heat pressing of the articulating surface of the PCA components may contribute to the problem.

It has long been realized that many patients who have their lower limbs amputated have a difficult and prolonged period of rehabilitation consequent upon stump difficulties. We would like to describe a scheme which eliminates, to a large degree, many of these troubles. The "immediate" walking of a patient who has had his lower limb amputated was first suggested by Professor Marian Weiss of Poland during the Ninth World Congress of the International Society for Rehabilitation of the Disabled held in Copenhagen in 1963., (Copyright © 1966 Australian Physiotherapy Association. Published by . All rights reserved.)

Anyone who has watched the removal of a limb in the operating theatre will have experienced the sinking feeling that accompanies the final irretrievable severance of the part. It is not difficult, therefore, to imagine the feelings of the patient who recovers from the anaesthetic minus a limb, in a deal of pain, and facing an incomprehensible future., (Copyright © 1972 Australian Physiotherapy Association. Published by . All rights reserved.)