Laminar airflow versus turbulent airflow in simulated total hip arthroplasty: measurements of colony-forming units, particles, and energy consumption.

BACKGROUND: The optimal type of ventilation in operating theatres for joint arthroplasty has been debated for decades. Recently, the World Health Organization changed its recommendations based on articles that have since been criticized. The economic and environmental impact of ventilation is also currently an important research topic but has not been well investigated. AIM: To compare how large, high-volume, laminar airflow (LAF) and turbulent airflow (TAF) ventilation systems perform during standardized simulated total hip arthroplasty (THA), as they pertain to colony-forming units (cfu), particle counts, and energy consumption. METHODS: Two identical operating theatres were used to perform simulated THA. The only difference was that one was equipped with LAF and the other with TAF. Cfu and particles were collected from key points in the operating theatre, and energy was measured for each simulation. Thirty-two simulations were done in total. FINDINGS: LAF had significantly reduced cfu and particle count when compared with TAF, at both 100% and 50% air influx. Furthermore, it was shown that lowering the air influx by 50% in LAF did not significantly affect cfu or particles, although reducing the fresh air influx from 100% to 50% significantly lowered the energy consumption. Most simulations in TAF did not meet the cleanroom requirements. CONCLUSION: Cfu were significantly lower in LAF at both 100% and 50% air influx. It is possible to reduce fresh air influx in LAF operating theatres by 50%, significantly reducing energy consumption, while still maintaining cfu and particle counts below the ISO classification threshold required for THA surgery.

Changes in clavicle length in acute fractures within 3 weeks: a prospective ultrasonographic study of 59 patients.

BACKGROUND: Within traumatology a common indication for acute surgery of fractured clavicles is bone shortening over 2 cm. This indication is among but a few indications; which are recommended to be treated operatively within the very first weeks after a fracture. Theoretically clavicle fractures could become less shortened over time due to decreasing muscle pull. If this reduced shortening does indeed happen, some patients with initial bone shortening over 2 cm could perhaps be treated conservatively? However, it is unknown what happens to the length of the clavicle within the first weeks after a fracture. The aim of this study was to investigate if the length of the fresh fractured clavicles changes within the first three weeks. METHODS: Rested length measurements using navigation ultrasound were done on 59 patients with a fractured clavicle. Measurements were performed within the first three weeks after a lateral or mid-clavicular fracture. The inclusion period was from March 2014 to February 2016. Median age was 40 years and age range was 18-81 years. The data was analyzed using mixed linear models. RESULTS: The clavicle length showed no change within the first three weeks after fracture (p = 0.24). CONCLUSION: Fractured clavicles retain their length for the first three weeks.

Bone shortening of clavicular fractures: comparison of measurement methods.

BACKGROUND: The indication for operative treatment of clavicular fractures with bone shortening over 2 cm is much debated. Correct measurement of clavicular length is essential, and reliable measures of clavicular length are therefore highly requested by clinical decision-makers. The aim of this study was to investigate if three commonly scientifically used measurement methods were interchangeable to each other. METHODS: A retrospective study using radiographs collected as part of a previous study on clavicular fractures. Two independent raters measured clavicle shortening on 60 patients using conventional radiographs on two separate sessions. The two measurement methods described by Hill et al. and Silva et al. were used on unilateral pictures. Side difference measurements according to Lazarides et al. were made on panoramic radiographs. The measurements were analyzed using intraclass correlation, Weir's protocol for Standard error of measurement (SEM) and minimal detectable change (MDC), and Bland-Altman plots. RESULTS: None of the methods were directly interchangeable. The side difference method by Lazarides et al. was the most reliable of the three methods, but had a high proportion of post-fracture bone lengthening that indicated methodological problems. The Hill et al. and Silva et al. methods had high minimal detectable change, making their use unreliable. CONCLUSION: As all three measurement methods had either reliability or methodological issues, we found it likely that differences in measurement methods have caused the differences in clavicular length observed in scientific studies.

Chronic pain and the development of a symptom checklist: a pilot study.

BACKGROUND: There is currently no instrument to systematically assess the range of symptoms/problems and their bothersomeness in patients with chronic non-cancer pain (CNPN). Systematic assessment and prioritizing may target treatments and improve outcomes. METHODS: The authors developed a checklist of symptoms and problems, the Copenhagen Symptom Checklist (CSC), presented clinically by patients. Fifty-three items representing biological, psychological and social areas were selected. Symptom/problem severity was rated on a 5-point scale anchored at 0 = 'not at all' and 4 = 'severe'. Patients ranked the five most bothersome symptoms/problems and could add five open-ended items. Patients completed the CSC after the first visit at the multidisciplinary pain centre. RESULTS: One hundred and twelve consecutive patients completed the CSC. Eighty-nine percent scored pain as rather severe or very severe (score = 3 plus score = 4), followed by reduction in physical activity (67%), fatigue (66%) and sleep disturbance (53%). Pain and fatigue, but not reduction in physical activity, were given highest priority. Cognitive problems were important to a third of the patients. Depressive symptoms, cognitive problems and worry explained 17.5% of the total variance. Patients filled in the CSC without important loss of information, but a minority prioritized more than three areas or used the free text alternative. CONCLUSIONS: Patients prioritized pain and fatigue as the most burdensome symptoms, but reduction in physical activity and sleep problems were also highly ranked. Patients were positive to the idea of symptom reporting; however, the 53-item number in this version of CSC is larger than may be necessary.

Cognitive function in patients with chronic pain treated with opioids: characteristics and associated factors.

BACKGROUND: The paucity of studies regarding cognitive function in patients with chronic pain, and growing evidence regarding the cognitive effects of pain and opioids on cognitive function prompted us to assess cognition via neuropsychological measurement in patients with chronic non-cancer pain treated with opioids. METHODS: In this cross-sectional study, 49 patients were assessed by Continuous Reaction Time, Finger Tapping, Digit Span, Trail Making Test-B and Mini-mental State Examination tests. Linear regressions were applied. RESULTS: Patients scored poorly in the Trail Making Test-B (mean = 107.6 s, SD = 61.0, cut-off = 91 s); and adequately on all other tests. Several associations among independent variables and cognitive tests were observed. In the multiple regression analyses, the variables associated with statistically significant poor cognitive performance were female sex, higher age, lower annual income, lower schooling, anxiety, depression, tiredness, lower opioid dose, and more than 5 h of sleep the night before assessment (P < 0.05). CONCLUSIONS: Patients with chronic pain may have cognitive dysfunction related to some reversible factors, which can be optimized by therapeutic interventions.

Validation and usefulness of the Danish version of the Pain Medication Questionnaire in opioid-treated chronic pain patients.

BACKGROUND: Addiction is a feared complication of long-term opioid therapy for chronic pain patients. A screening tool to assess the potential risk of addiction may be helpful. METHODS: The Pain Medication Questionnaire (PMQ) was translated into Danish by a 'forward' and 'backward' translation procedure. Patients with chronic non-cancer pain and cancer pain treated at a tertiary pain center were screened for addiction using Portenoy's criteria and invited to answer the Danish version of the PMQ. RESULTS: Two hundred nine patients participated in the study. PMQ was able to discriminate between addicted and non-addicted patients. Patients with high PMQ scores indicating a risk of addiction drank more alcohol, smoked more tobacco, used higher doses of morphine, had a higher anxiety and depression score, and had poorer mental health. Using a cut-off score of 22, the PMQ had a sensitivity of 82%, but the specificity at this cut-point was 56%, indicating a risk of false positive cases. Convergent and discriminant validity were confirmed by correlation with opioid doses, alcohol and tobacco use, anxiety and depression scores, and inverse correlation with mental health and social role. Test-retest showed a very strong correlation. Cronbach's alpha for internal consistency was 0.61. Ten components were found to have eigenvalues above 1.0, confirming the multidimensional structure of the questionnaire. CONCLUSIONS: The PMQ may assist physicians in addiction risk assessment and stratification when treating chronic pain patients with opioids. PMQ is not a diagnostic tool and should only be used as an indicator for possible addiction problems.

Hepatic radiofrequency ablation using perfusion electrodes in a pig model: effect of the Pringle manoeuvre.

AIM: To assess the influence of the Pringle manoeuvre on volume and geometry of coagulations close to the portal vein using an impedance-controlled radiofrequency ablation system with perfusion electrodes. METHODS: Twelve pigs were randomly assigned to a control group (n = 6) and a group where the Pringle manoeuvre was applied during ablation (n = 6). One coagulation was made in each animal close to the portal vein. All animals were sacrificed 4 days after ablation, and the livers were removed for gross and histopathologic analysis. RESULTS: Effective coagulation volume in the Pringle group (10.8 +/- 5.0 cm(3)) was significantly increased (p = 0.03) compared to the control group (4.1 +/- 4.1 cm(3)). The efficacy ratio, defined as the effective coagulation volume divided by the coagulation volume, was not significantly different in the Pringle group (0.47 +/- 0.27) compared to the control group (0.33 +/- 0.22). The geometrical centre of the effective coagulation volume did not correspond to the position of the ablation electrode. Thermal damage of the gallbladder was found in three animals, all belonging to the Pringle group. CONCLUSIONS: The Pringle manoeuvre was associated with increased effective coagulation volume, but did not significantly influence the predictability of coagulation volume or geometry.

Work related shoulder disorders: quantitative exposure-response relations with reference to arm posture.

AIMS: To determine quantitative exposure-response relations between work with highly elevated arms and supraspinatus tendinitis, shoulder pain with disability, and shoulder pain without disability. METHODS: A cross sectional study was conducted in a historical cohort of 1886 males from three occupational groups. Exposure measurements were performed for four consecutive working days in a random sample of 72 currently employed subjects. Individual work histories were obtained by questionnaire and register data. Health status was ascertained by physical examination blinded towards exposure and symptoms. Data were analysed by generalised estimating equation and multiple logistic regression with adjustment for potential confounders. RESULTS: For current upper arm elevation above 90 degrees, a duration increment of 1% of the daily working hours was associated with odds ratios of 1.23 (95% CI 1.10 to 1.39) for supraspinatus tendinitis, 1.16 (95% CI 1.08 to 1.24) for shoulder pain with disability, and 1.08 (95% CI 1.04 to 1.13) for shoulder pain without disability. The outcomes were not related to duration of employment in one of the three trades. CONCLUSIONS: Quantitative exposure-response relations were established between current work with highly elevated arms and clinically verified shoulder disorders. Substantial long term cumulative effects were not shown. A potential for primary prevention was revealed.

A three-dimensional finite element model from computed tomography data: a semi-automated method.

Three-dimensional finite element analysis is one of the best ways to assess stress and strain distributions in complex bone structures. However, accuracy in the results may be achieved only when accurate input information is given. A semi-automated method to generate a finite element (FE) model using data retrieved from computed tomography (CT) was developed. Due to its complex and irregular shape, the glenoid part of a left embalmed scapula bone was chosen as working material. CT data were retrieved using a standard clinical CT scanner (Siemens Somatom Plus 2, Siemens AG, Germany). This was done to produce a method that could later be utilized to generate a patient-specific FE model. Different methods of converting Hounsfield unit (HU) values to apparent densities and subsequently to Young's moduli were tested. All the models obtained were loaded using three-dimensional loading conditions taken from literature, corresponding to an arm abduction of 90 degrees. Additional models with different amounts of elements were generated to verify convergence. Direct comparison between the models showed that the best method to convert HU values directly to apparent densities was to use different equations for cancellous and cortical bone. In this study, a reliable method of determining both geometrical data and bone properties from patient CT scans for the semi-automated generation of an FE model is presented.

Familial occurrence of nonmedullary thyroid cancer: a population-based study of 5673 first-degree relatives of thyroid cancer patients from Norway.

The purpose of this study was to estimate the occurrence of familial nonmedullary thyroid cancer (FNMTC) in a large population-based study. Of the 5274 cases of thyroid cancer on record in the Norwegian Cancer Registry between 1960 and 1995, a total of 1025 patients could be identified with verified thyroid cancer, a unique personal identification number, and a link to at least one parent. For patients with nonmedullary carcinoma, 5457 first-degree relatives in 970 families were found, compared with 216 first-degree relatives in 37 families for the medullary cancers. A standardized incidence ratio (SIR) was calculated among the relatives based on rates from the Cancer Registry of Norway. A significantly increased risk of thyroid cancer was found among the 5457 relatives of nonmedullary index cases, both for males [SIR, 5.2; confidence interval (CI), 2.1-10.7; 7 cases] and females (SIR, 4.9; CI, 3.0-7.7; 19 cases). All of these 26 thyroid cancer cases were of the nonmedullary type. Furthermore, an increased risk was found among 4282 relatives of papillary index cases, for both males (SIR, 5.8; CI, 2.1-12.6; 6 cases) and females (SIR, 4.0; CI, 2.1-7.1; 12 cases). The 36 familial papillary thyroid cancer patients had an average age at diagnosis of 43 years. Genetic influence is probably only modest for the familial nonmedullary cases and clearly weaker than for the classic familial type of medullary thyroid cancer.

[Cryoablation--a treatment option for inoperable liver tumors?]. / Kryoablasjon--aktuell behandling av inoperable leversvulster?

BACKGROUND: Most patients with primary and secondary liver tumours are inoperable by conventional surgery. This has prompted the development of different techniques of local destruction of liver tumours, i.e. cryosurgical ablation radiofrequency, laser, and microwave ablation. MATERIAL AND METHODS: On the basis of relevant literature and our own experience we describe the principles of local destruction by cryoablation of colorectal metastases. RESULTS: Indications for ablation are mainly colorectal metastases and hepatocellular carcinoma. Mechanisms for tumour destruction include intra- and extracellular ice crystal formation, cellular membrane rupture, cellular dehydration and ischaemic damage. Ablation is regularly monitored by ultrasonography, which is suboptimal because of inadequate visualisation of the iceball. Long-term outcome of local destruction of liver tumours is not documented and randomized trials are not ethically acceptable. This complicates analyses of patient outcomes. INTERPRETATION: Local ablation of liver tumours is experimental therapy and should only be performed as a part of prospective trials.

Pain and pain treatment in AIDS patients: a longitudinal study.

To determine the prevalence, incidence, and characteristics of pain connected with AIDS, 95 AIDS patients were enrolled in a prospective longitudinal study and interviewed every six months during a 2-year period or until death. The overall incidence of pain was 88%, and 69% of the patients suffered from constant pain interfering with daily living to a degree described as moderate or severe. The most common pain localizations were: extremities (32%), head (24%), upper gastrointestinal tract (23%) and lower gastrointestinal tract (22%). Pain conditions were connected to various opportunistic infections, Kaposi's sarcoma, or lymphoma. Pain in the extremities was predominantly of neuropathic origin (21%). The number of pain localizations increased significantly as death approached (0.8 +/- 1. 0 vs. 1.4 +/- 0.8, p = 0.03). The survival rate for patients without pain at entry was significantly higher than the survival rate of patients in pain, probably related to differences in the duration of AIDS at the time of inclusion. Sustained-release morphine preparations were prescribed in 29% of the patients. Of 39 patients (41%) who died in the department, 7 patients were prescribed continuous intravenous morphine infusion for pain treatment in the terminal phase and 20 patients received short-acting opioids. According to the Pain Management Index (PMI), the patients were insufficiently treated at the beginning of the study. Although the PMI improved significantly during the observation period, the patients felt that pain was not taken seriously by the physicians. However, the patients were convinced that treatment was optimal and, therefore, only 9% of the patients were dissatisfied. Patients were reluctant to take analgesics, primarily because of fear of addiction.

Late results of total shoulder replacement in patients with rheumatoid arthritis.

Rheumatoid arthritis of the shoulder is a progressive and destructive joint disease, and similar to arthritis in other joints, progression of the disease is unpredictable and may stop at any stage of involvement. Between 1983 and 1996, more than 500 shoulder prostheses were implanted in patients at the authors' institution. Total shoulder replacement yields satisfactory short and long term results even in patients with severely destructed joints. Pain relief is reliable and significant as reported in short and long term studies. In most patients the functional result is good or acceptable. Although range of motion is only slightly increased, a satisfactory overall range of motion is achieved by most patients because of the unaffected scapulothoracic motion. However, deteriorating results, emphasizing the complexity of shoulder arthroplasty, were seen with increasing observation time in patients with rheumatoid arthritis. Proximal migration of the humeral prosthesis attributable to rotator cuff failure, with secondary eccentric glenoid loading and progressive loosening, is latent in patients with chronic progressive rheumatoid disease and was by far the most common complication (42%) in the present series.

[Increased incidence of thyroid cancer among Norwegian women married to fishermen]. / Okt forekomst av kreft i skjoldkjertelen blant norske kvinner gift med fiskere.

The relationship between thyroid cancer in women and the occupation of their spouses was examined in a retrospective cohort study. Of the 2.9 million women registered in the Central Population Registry of Norway by the end of 1991, 1.2 million had a spouse registered with an occupation in one or more of the censuses of 1960, 1970 or 1980. These women were included in the study. Based on the first digit of their husbands' five-digit Nordic occupational code, the women were assigned to ten broad categories. A standardised incidence ratio (SIR) and 95% confidence interval were calculated for each occupational category. The women were further subdivided and analysed in 71 groups defined by the first two digits of their husband's occupational code. Among the women included in the study, a total of 2,409 cases of thyroid cancer were reported to the Cancer Registry of Norway during the period 1960-92. A significantly elevated risk of thyroid cancer was found only among women whose spouses belonged to the occupational category Agriculture, forestry or fishery (n = 208,279), with a SIR of 1.13. In the subgroup Fishing, whaling and sealing work (n = 40,839), the risk was even higher with a standardised incidence ratio of 1.91. Our data support the proposed relationship between increased risk of thyroid cancer and mode of living, more specifically dietary fish or other seafood.

Glenoid bone architecture.

This article describes regional variations in trabecular bone architecture in terms of density and orientation within six glenoid specimens. The mean donor age was 56 years and ranged from 31 to 72 years. An automated imaging technique based on 3-dimensional serial sectioning was used for the direct examination of the glenoid cancellous bone structures. Subchondral plate thickness was on average 1.9 mm and ranged from 1.2 mm to 2.9 mm. The volume fraction of trabecular bone varied from 11% to 45% with peak values at the posterior glenoid vault. On graphic 3-dimensional reconstructions, the glenoid appeared as platelike trabeculae, radially oriented perpendicular to the subchondral plate and interconnected by thin rods. These views also displayed regional variations throughout the glenoid, reflecting differences in the macroscopic appearance. Quantitative structural analysis revealed different degrees of anisotropy at the glenoid cancellous region, predominantly transverse isotropy. Resemblance to direct weight-bearing cancellous bone such as the proximal tibia was evident.

Bone strength and material properties of the glenoid.

The quality of the glenoid bone is important to a successful total shoulder replacement. Finite element models have been used to model the response of the glenoid bone to an implanted prosthesis. Because very little is known about the bone strength and the material properties at the glenoid, these models were all based on assumptions that the material properties of the glenoid were similar to those of the tibial plateau. The osteopenetrometer was used to assess the topographic strength distribution at the glenoid. Strength at the proximal subchondral level of the glenoid averaged 66.9 MPa. Higher peak values were measured posteriorly, superiorly, and anteriorly to the area of maximum concavity of the glenoid joint surface known as the bare area. One millimeter underneath the subchondral plate, average strength decreased by 25%, and at the 2 mm level strength decreased by 70%. The contribution of the cortical bone to the total glenoid strength was assessed by compression tests of pristine and cancellous-free glenoid specimens. Strength decreased by an average of 31% after the cancellous bone was removed. The material properties of the glenoid cancellous bone were determined by axial compression tests of bone specimens harvested from the central part of the glenoid subchondral area. The elastic modulus varied from approximately 100 MPa at the glenoid bare area to 400 MPa at the superior part of the glenoid. With the elastic constants used a predictor of the mechanical anisotropy, the average anisotropy ratio was 5.2, indicating strong anisotropy. The apparent density was an average 0.35 gr. cm-3, and the Poisson ratio averaged 0.263. According to our findings the anisotropy of the glenoid cancellous bone, details concerning the strength distribution, and the load-bearing function of the cortical shell should be considered in future finite element models of the glenoid.

Increased risk of thyroid cancer among Norwegian women married to fishery workers--a retrospective cohort study.

The relationship between thyroid cancer in women and the occupation of their spouses was examined in a retrospective cohort study, with special reference to fishery. Of the 2.9 million women registered in the Central Population Registry of Norway on 31 December 1991, 1.2 million women had a spouse registered with an occupation in one or more of the censuses in 1960, 1970 or 1980. The women were assigned to ten broad categories based on the first digit of their husbands five-digit Nordic occupational classification code NYK, and a standardized incidence ratio (SIR) was calculated for each occupational category. The women were further subdivided and analysed in 71 groups defined by the first two digits of the NYK code. Among the women included in the study, a total of 2409 cases of thyroid cancer were reported to the cancer registry of Norway during 1960-92. A significantly elevated risk of thyroid cancer was found only among women whose spouses belonged to the occupational category 'agriculture, forestry or fishery' (n = 208 279), with a SIR of 1.13. In the group associated with 'fishing, whaling and sealing work' (n = 40 839), the risk was further increased (SIR 1.91, CI 1.65-2.21). An increased risk was also detected in the group associated with 'ship officers and pilots work' (n = 29 133) (SIR 1.35, CI 1.07-1.67). When allocating the women to southern and northern cohorts determined by their county of birth, a difference in risk was clearly present in all 10 occupational categories, with figures being 50-60% higher in the north. However, there was practically no difference in incidence between northern and southern cohorts among women associated with fishery work. Thus, the results obtained from this study indicate that being a fisherman's wife is associated with elevated risk of thyroid cancer, and our data support the suggested role of seafood as an aetiological factor.

[When a physician makes a mistake]. / Når legen gjør feil.

Inevitably, doctors make mistakes in the normal course of providing care. Making a mistake often causes distress for the doctor involved, but it can also be an important source of knowledge and self-reflection. This article discusses central aspects with respect to mistakes and medical malpractice. The doctor's relationship to ethics and legislation is discussed, and an overview of the administrative action taken by the Norwegian health authorities is presented. The organisations and offices a physician may come into contact with when involved in a patient's complaint are briefly presented. "Meldesentralen" was formed in 1993 by the Norwegian Directorate of Health for the purpose of collecting reports on accidents in medical practice. We argue that the accidents reported to "Meldesentralen" do not reflect the true situation on this issue. We introduce a model for a systematic approach towards a colleague who has made a mistake or who is suspected of having made one.

[Pain and treatment of pain in patients with AIDS]. / Smerter og smertebehandling hos AIDS-patienter.

Published articles report that 50-97% of patients with AIDS experience pain. The aim of the study was to determine the incidence and characteristics of pain connected with AIDS, to register pain treatment and patients' evaluation of such treatment. Ninety-five patients with AIDS underwent a semistructured interview. The overall incidence of AIDS-related pain was found to be 74%. Fifty-two percent of the patients experienced pain every day or constantly to a degree described as "some or severe". Thirty-one percent of the patients had a pain duration of more than three months and 25% of the patients were never free from pain. Eleven percent received medical pain treatment on a steady hourly basis. Despite these results, the majority of the patients were satisfied with the treatment and only three percent stated that they were not satisfied. It is concluded that patients with AIDS have a higher incidence of pain, which appears to be undertreated. The reason for this undertreatment is multifactorial. The patients appear to be very reluctant to receive medical pain treatment.