Rupture of the brachioradialis muscle following blunt trauma. A case report.

A 50-year old healthy male lost control over the pull string of a milling machine, which strangulated his right elbow and forearm with high velocity. Magnetic resonance imaging of the right upper extremity revealed a substantial tear in the muscle belly of the musculus brachioradialis with multiple small defects in the surrounding musculature of the forearm. The affected arm was immobilized for 1 week with an above the elbow cast. In the following months, guided training and strengthening exercises were performed. The patient could return to his physically demanding work after 10 months and regained full function of his hand and wrist after 18 months. This case report demonstrates that short immobilization followed by extensive and guided strength training has been observed to result in persisting weakness of elbow flexion but good functional outcome for the wrist and hand.

Major Haemorrhage during Vitamin K Antagonist Treatment: The Influence of Thyroid Hormone Levels.

BACKGROUND: Annually, approximately 1-3% of patients treated with vitamin K antagonists (VKA) suffer from major haemorrhage. Since high levels of free thyroxine (fT4) are associated with increased thrombosis risk, the aim was to assess whether low levels of fT4 contribute to major haemorrhage in patients under VKA treatment. METHODS: The FACTORS (Factors in Oral Anticoagulant Safety) study is a case-control study on patients receiving VKA treatment, including 110 cases with major haemorrhage. Controls were 220 matched participants treated with VKA without major haemorrhage. Odds ratios (OR) and 95% confidence intervals (95% CI) for the association of fT4 levels with major haemorrhage were calculated for different fT4 cutoffs by conditional logistic regression. RESULTS: In patients with an fT4 level below 13 pmol/l, the risk of major haemorrhage was 5-fold increased (OR = 5.1; 95% CI: 0.9-28.6) compared with patients with an fT4 level above 13 pmol/l. At a cutoff of 14 pmol/l, the risk was 3-fold increased (OR = 2.9; 95% CI: 1.0-8.5). High levels of fT4 did not affect bleeding risk. No clear effect of thyroid-stimulating hormone and thyroid peroxidase antibodies was seen on the risk of major haemorrhage. CONCLUSIONS: These results indicate that fT4 levels below 14 pmol/l play a role in the aetiology of major haemorrhage in VKA users.

Effect of acetylsalicylic acid on microvascular thrombosis in autologous breast reconstruction.

Although advances in microsurgery have increased success rates of autologous breast reconstruction, microvascular thrombosis still remains a major concern as a cause of flap failure. At present, no evidence-based guidelines on pharmacological prevention of microvascular thrombosis exist. This study investigates the effect of acetylsalicylic acid on the incidence of microvascular complications in patients undergoing autologous breast reconstruction. Patients undergoing deep inferior epigastric artery perforator or free transverse rectus abdominis myocutaneous flap breast reconstruction at two academic centers in the Netherlands between 2005 and 2011 were included. Patients at one center received once daily 0.6 mL of nadroparine and 40 mg acetylsalicylic acid, while patients at the other center received 0.6 mL nadroparine only. A total of 430 consecutive patients underwent 592 breast reconstructions. No statistically significant differences were found between the two groups in the incidence of flap failure (2.8 and 2.5%), microvascular thromboembolic complications (2.6 and 3.8%), venous congestion (3.4 and 2.8%), or overall complications (28.0 and 32.3%). Hematoma tended to occur more often in the group receiving acetylsalicylic acid (9.2 and 4.7%).It was found that no protective effect of acetylsalicylic acid on microvascular complications was present. Given its known risks and the somewhat increased occurrence of hematoma in the present study, we stopped to routinely administer acetylsalicylic acid after autologous breast reconstruction.

Levels of prolactin in relation to coagulation factors and risk of venous thrombosis. Results of a large population-based case-control study (MEGA-study).

The pituitary hormone prolactin is thought to influence coagulation. We aimed to study the relation between prolactin levels, coagulation factors and risk of venous thrombosis (VT). We used data from a large population based case-control study into aetiology of first VT (MEGA-study). Prolactin levels were determined in 2,068 patients with VT and 2,785 age- and sex matched control subjects. The relation between levels of coagulation factors and prolactin was studied among the controls. In addition, odds ratios (OR) and 95% confidence intervals (95%CI) were calculated for the risk of VT for different cut-off points of prolactin levels based on percentiles determined in the controls. Restricted analysis was performed among cases in whom blood was sampled within six months after VT. We found a rise in factor VIII and von Willebrand factor with increasing levels of prolactin in the controls. An increased risk of VT was observed when blood was sampled within six months after thrombosis (OR 2.9, 95%CI 1.1-8.1) for prolactin levels above the 99th percentile (42.6 µg/l) relative to levels between the 20th to 80th percentile. When blood was sampled more than six months after VT no clear association could be observed (OR 1.3, 95%CI 0.7-2.3). In conclusion, we found a modest association between prolactin and symptomatic venous thromboembolism, particularly when blood was sampled close to the event. This may be explained by a causal relation or by prolactin being a marker of stress due to the thrombotic event.

Quantification of bias in direct effects estimates due to different types of measurement error in the mediator.

Assessing whether the effect of exposure on an outcome is completely mediated by a third variable is often done by conditioning on the intermediate variable. However, when an association remains, it is not always clear how this should be interpreted. It may be explained by a causal direct effect of the exposure on the disease, or the adjustment may have been distorted due to various reasons, such as error in the measured mediator or unknown confounding of association between the mediator and the outcome.In this paper, we study various situations where the conditional relationship between the exposure and the outcome is biased due to different types of measurement error in the mediator. For each of these situations, we quantify the effect on the association parameter. Such formulas can be used as tools for sensitivity analysis or to correct the association parameter for the bias due to measurement error. The performance of the bias formulas is studied by simulation and by applying them to data from a case-control study (Leiden Thrombophilia Study) on risk factors for venous thrombosis. In this study, the question was the extent to which the relationship between blood group and venous thrombosis might be mediated through coagulation factor VIII. We found that measurement error could have strongly biased the estimated direct effect of blood group on thrombosis. The formulas we propose can be a guide for researchers who find a residual association after adjusting for an intermediate variable and who wish to explore other possible explanations before concluding that there is a direct causal effect.