Fate of Bronchial Ligatures

Abstract

It is well known that non-absorbable ligatures and sutures applied to some tubular structures in the body tend to migrate. The special mode of migration of such material in the intestine, common bile duct, Fallopian tubes, and large arteries has been determined in detail. The present work concerns the behavior of ligatures applied to a tertiary bronchus, and the resultant effect upon the bronchial continuity, in dogs.

The first branch (about 4 mm. in diameter) of the stem bronchus of the right lower lobe was exposed, and ligated with silk. In 9 dogs, it was singly ligated; in 8 other dogs it was ligated at 2 points and divided between the ligatures. After postoperative periods varying from 3 days to 6 months, the animals were killed and the region of ligation was examined grossly and microscopically (using serial microscopic sections).

In every case of single ligation, before the 7th day, the thread cut through the bronchial wall at one point. The process continued, more or less gradually, until the ligature became entirely free and lay in the lumen. Almost as fast as the ligature cut through, the resultant circular ulcer became filled with granulations and covered with bronchial epithelium. At 6 months, the ligature had disappeared, presumably to the outside, the bronchial lumen was patent, and the walls were healed. There was little or no stricture. The mucosa was normal, but under it was a microscopic circumferential scar.

In every case of double ligature, the bronchus remained obstructed. The proximal stump (the one next to the stem bronchus) healed without any interruption; but within 14 days a small ulcer developed in the mucosa of the distal bronchial segment, at a point just over the distal ligature, and it stayed open until both ligatures and nearly the whole mass of pinched off cartilages had gradually worked their way into the lumen of the distal bronchial segment. At 6 months, the ulcer was healed and the fragments of silk thread were lying in the lumen distal to the site of bronchial interruption. The portion of the pinched off cartilages which failed to migrate underwent absorption in situ.