External fixation of subglottic tracheal stents.

Bronchoscopically placed silicone stents are used increasingly for treating patients with tracheal stenosis due to benign or malignant airway disease. When stenosis occurs in the immediate subglottic region, however, complications of stent insertion, especially migration, are troublesome. The purpose of this report is to describe a technique of external fixation of subglottic stents that may be used when tracheotomy, Montgomery T-tubes, or other therapeutic measures are undesirable or have failed. This technique may also be considered in carefully selected patients with severe malacia and subglottic stenosis who have failed indwelling stent placement because of stent migration.

Three-dimensional motion of the arytenoid adduction procedure in cadaver larynges.

To determine whether variation in suture placement could improve the results of the arytenoid adduction procedure, a model was developed using fresh human cadaver larynges. Three-dimensional (3-D) motion of the arytenoid was determined by utilizing computed tomographic imaging with radiopaque markers on the apex and muscular and vocal processes. By utilizing principles previously applied to the study of rigid body mechanics for the carpal, knee, and tarsal joints, rotation and translation of the arytenoid about the axial, coronal, and sagittal axes were calculated. Subglottic airflow resistance was measured before and after the procedure. Posterior glottic closure was reproducibly achieved, as determined by computed tomographic imaging and airway resistance. Conflicting reports on cricoarytenoid joint mechanics can be attributed to reliance on trigonometric analysis of two-dimensional images, which results in errors in out-of-plane motion. This paper presents a useful model for obtaining detailed anatomic information describing arytenoid 3-D motion.

Rapid determination of molecular relatedness of isolates of human cytomegalovirus.

Molecular comparisons of isolates of human cytomegalovirus (CMV) with restriction enzyme digests have helped to identify patterns of CMV transmission. Current techniques, however, require extensive tissue culture passage of the virus, which limits use of these analyses. In this report, we describe a rapid, less-expensive, and equally sensitive method of comparing CMV genomes. This procedure, which we have called "junctional hybridization," uses the cloned junction fragments of CMV strain AD169 as probes that hybridize to CMV DNA restriction digests previously separated by electrophoresis and transferred to nitrocellulose filters. The procedure eliminates the need for tissue culture passage of virus beyond the primary isolation and can be used directly with DNA extracted from CMV-infected tissue. In all cases, junctional hybridization was as sensitive as currently used methods of restriction enzyme digestion analyses in identifying identical or different CMV isolates. Use of junctional hybridization should facilitate molecular analyses for study of the epidemiology of CMV infections.