ASSESSMENT OF CURRENT TECHNIQUES FOR DETERMINING TRACHEAL LUMINAL STENOSIS IN DOGS

Objective-To assess the accuracy of current antemortem and postmortem techniques for determining tracheal luminal stenosis. Animals-15 dogs. Procedure-Percentage of tracheal luminal stenosis (PTLS) was determin ed by 6 methods, using measurements obtained by radiography, tracheosc opy, and necropsy after selected tracheostomy techniques were performe d. To calculate PTLS, dorsoventral tracheal diameter was measured from preoperative and postoperative lateral cervical radiographic views. P reoperative or normal tracheal segments adjacent to the stenotic area were used to obtain normal tracheal diameter measurements. Planimetric ally determined cross-sectional area (CSA), obtained from pre- and pos toperative tracheoscopic photographs, was used to calculate PTLS. The CSA of tracheal specimens obtained at necropsy was determined, using t he formula for an ellipse. Percentage of luminal stenosis was calculat ed, using CSA of the stenotic site and of segments craniad and caudad to the site obtained at necropsy or at surgery. Ail methods were compa red with the control method of planimetrically determined CSA of secti ons obtained at necropsy of the tracheostomy and segments craniad and caudad to the site. Results-Correlation was poor for radiographic and tracheoscopic techniques (r = 0.146 to 0.458, P > 0.05) The formula fo r an ellipse accurately predicted PTLS when measurements obtained at s urgery (r = 0.516, P = 0.049) or segments craniad and caudad (r = 0.85 3, P < 0.001) to the site were used. Conclusion-Antemortem methods of assessing PTLS did not correlate with control planimetric methods. Met hods using CSA determined by tracheal diameter were weakly correlated to control planimetric techniques. Clinical Relevance-Accurate measure ment of the degree of tracheal stenosis cannot be made in clinical pat ients using current techniques.