Apron tracheostome

Age-dependent sexual selection in bighorn rams

Although mating systems and sexual selection have been intensively studied in ungulate model systems, very few studies have combined genetic paternity analysis with individual phenotypic data over several breeding seasons. We used microsatellite paternity analysis to determine the parentage of 83 bighorn sheep (Ovis canadensis) born between 1995 and 2000 at Ram Mountain, Alberta, Canada. We could assign the paternity of 64 lambs at a high level of statistical confidence (95%). Within each season, the most successful ram sired an average of 35.5% of the lambs with assigned paternity, and a single ram sired 26.1% of all lambs over the six mating seasons. Although a few large-horned, mature (age 8+ years) rams had very high reproductive success, younger rams sired ca. 50% of the lambs. Mixed-effects models indicated that mating success increases as a nonlinear function of age, with horn length increasingly positive in correlation with mating success in older rams. These results indicate that young or small rams possibly achieve mating success through alternative mating tactics that are less dependent on body and weapon size, such as coursing and blocking. Sexual selection is therefore likely to have age-dependent effects on traits such as agility, body and horn size.

Surgical treatment of tracheostomal stenosis

HYPOTHESIS

Stenosis of the tracheostome is a frequent complication following total laryngectomy; the problems created by tracheostomal stenosis are the result of reduced airflow and consequent turbulence. Many authors have studied etiological factors for the onset of stomal stenosis, and a number of procedures have been recommended for the surgical correction of such stenosis.

STUDY DESIGN

A prospective analysis of 12 patients who underwent surgical correction of stomal stenosis is presented.

METHODS

At the Institute of Clinical Otolaryngology we have recently defined a surgical technique for the correction of stomal stenosis that combines radial incisions, V-shaped flaps, and interposing flaps. This technique enables us to correct all the types of stenosis, and we have treated 12 patients to date.

RESULTS

To date, the average follow-up has been 17 months (range, 3-36 mo), and the results are encouraging. Early stenosis of the tracheostoma reappeared in one patient, who had successful repeat surgery with the same technique.

CONCLUSIONS

Early results suggest the routine use of this surgical technique in the treatment of stomal stenosis.

Does the location of the laryngectomy stoma influence its ultimate size?

The stoma following laryngectomy may be placed either within the incision or separately. To determine if this variation had a bearing on its ultimate size, measurements of the stoma size were carried out in 61 patients who underwent laryngectomy by one of these methods. It was found that the stoma was nearly twice the size in patients in whom the stoma had been sited within the main wound and that there was a minimal need for the use of a tube or stoma button post-operatively in these patients.