Postmenopausal use of estrogen and occlusion of coronary arteries

The degree of coronary artery occlusion was compared between users and nonusers of postmenopausal estrogen among 933 female patients undergoing angiography between the ages 50 and 75 years in the Milwaukee Cardiovascular Data Registry. Users (n = 154) had less occlusion than nonusers (n = 779), and a significant increase in occlusion scores with age was evident for nonusers (p less than 0.001) but not for users (p = 0.50). The age-adjusted odds ratios for use of postmenopausal estrogen among women with moderate and severe levels of occlusion of the coronary arteries were 0.59 (95% confidence interval, 0.48 to 0.73) and 0.37 (95% confidence interval, 0.29 to 0.46), respectively, which indicated a statistically significant, apparent protective effect of postmenopausal estrogen on coronary occlusion. This effect was independent of the type of menopause or other risk factors but not independent of high-density lipoprotein-cholesterol levels. Higher high-density lipoprotein-cholesterol levels among users may indicate a biologic mechanism by which postmenopausal estrogen use lowers the risk of coronary occlusion.     

Electromyographic investigation of unstable patella before and after its realignment operation

Background:

Patellar dislocations are either due to superolateral contracture of the soft tissue or imbalance of the power between the vastus medialis (VM) and the vastus lateralis (VL). The imbalance of muscle power as an etiology of patellar dislocation has not been studied. Hence, we studied the recurrent, habitual and permanent dislocations of the patella with an electromyogram (EMG) of the vastus medialis, vastus lateralis, and pes anserinus, before and after realignment operations, to document the muscle imbalance and effectiveness of the realignment operation.

Materials and Methods:

An electromyographic investigation was carried out on the vastus medialis and vastus lateralis in nine recurrent, 20 habitual, and 13 permanent dislocations of the patella, before and after their realignment operations. Pes anserinus transposition, which acted as a medial stabilizer of the patella, was also investigated with an EMG study, to understand its role on patellar stability at 0°, 30°, 60°, 90°, 120°, 150°, and full flexion of the knee. The age of the patients varied from nine to 30 (mean 15) years. There were 24 males and 18 females. Twenty-six patellar dislocations were on the right and 16 were on the left side.

Results:

Electromyographic pictures reveal subnormal activity of the vastus medialis in all types of dislocations and similar activities of the vastus lateralis in permanent and habitual dislocations recorded pre operatively, which recovered to almost normal values postoperatively, at the mean one-year follow-up. Pes anserinus, which was used for medial stabilization of the patella after its realignment, maintained normal EMG activity before and after the operation.

Conclusion:

This study is significant for understanding the imbalance of muscle activities in patients with an unstable patella, which can be rectified without recurrence after pes anserinus transposition.     

Learning curves in minimally invasive esophagectomy

Surgical innovation and pioneering are important for improving patient outcome, but can be associated with learning curves. Although learning curves in surgery are a recognized problem, the impact of surgical learning curves is increasing, due to increasing complexity of innovative surgical procedures, the rapid rate at which new interventions are implemented and a decrease in relative effectiveness of new interventions compared to old interventions. For minimally invasive esophagectomy(MIE), there is now robust evidence that implementation can lead to significant learning associated morbidity(morbidity during a learning curve, that could have been avoided if patients were operated by surgeons that have completed the learning curve). This article provides an overview of the evidence of the impact of learning curves after implementation of MIE. In addition, caveats for implementation and available evidence regarding factors that are important for safe implementation and safe pioneering of MIE are discussed.