Asian Cardiovasc Thorac Ann 2000;8:245-248
© 2000 Asia Publishing EXchange Pte Ltd
Absorbable and Nonabsorbable Sutures for Tracheal Anastomoses in Dogs
Levent Elbeyli, MD,
Yalçin Kepekci, MD1,
Department of Thoracic and Cardiovascular Surgery
1 Department of Internal Medicine
Gaziantep University School of Medicine
Gaziantep, Turkey
|
|
For reprint information contact: Levent Elbeyli, MD Tel: 90 342 336 5400 Fax: 90 342 339 8685 email: elbeyli{at}alpha.bim.gantep.edu.tr Department of Thoracic and Cardiovascular Surgery, Gaziantep University School of Medicine, Kolejtepe, Gaziantep 27070, Turkey.
|
 |
Abstract
|
|---|
Tracheal anastomosis was performed in 3 groups of 6 mongrel dogs each (mean age, 4 months; mean weight, 7 kg) to compare synthetic sutures. The interrupted technique was used for all anastomoses and they were evaluated by rigid bronchoscopy in the 3rd postoperative week. While suture absorption was observed in the Vicryl group, it was not visible in the Ethibond and polydioxanone groups. Dogs were sacrificed between 26 and 76 days (mean, 44 days) postoperatively. No stenosis was observed in any group. Histological evaluation of the epithelium showed a statistically significant difference in epithelization between Vicryl and Ethibond, and between polydioxanone and Ethibond. There was no difference between Vicryl and polydioxanone. These results suggest that absorbable suture material is superior for tension-free anastomoses.
|
Introduction
|
|---|
Developments in tracheal surgery have been limited because of the low incidence of tracheal disease, post-operative problems, special intubation needs, segmental vascular supply, the anatomic location, and cartilaginous structure. Tracheal repair has gained importance for tumor resection, tracheal stenosis, trauma, and lung transplan-tation, due to major developments in pulmonary surgical procedures in recent years. The most appropriate procedure to attain functional recovery and anatomic continuation in tracheal repair is primary end-to-end anastomosis. In spite of recent developments, there are still important problems to be resolved, such as stenosis, dysfunction, and anastomotic deficiency due to reaction of the tracheal tissue to foreign material. If epithelization is inefficient, stricture will be seen. In addition, luminal narrowing may occur in the late period due to scar formation, even when epithelization is complete. There are several options for the type of anastomosis and choice of suture material. Silk, nylon, polyester, and wire are used frequently as nonabsorbable sutures. Stenosis, granuloma, or both can occur with these sutures but less granulation tissue has been found with absorbable synthetic suture materials.1
Ethibond multifilament (Ethicon Ltd, Edinburgh, Scotland, UK) is a nonabsorbable synthetic polyester suture coated with polybutilate, which retains tensile strength for a long period and is resistant to tissue enzymes. Vicryl (Proglactin 910; Ethicon Ltd, Edinburgh, Scotland, UK) is an absorbable synthetic multifilament suture that is coated with a mixture of glycolic acid, lactic acid, and calcium stearate in equal proportions. It causes minimal tissue reaction.2 Polydioxanone (PDS) is an absorbable and more flexible monofilament that is more resistant to tension.3,4 The effects of these 3 different suture materials in end-to-end tracheal anastomosis by the interrupted suture technique were compared in this study.
|
Materials and Methods
|
|---|
Eighteen hybrid dogs, 3 to 8 months old, weighing 5 to 13 kg, were anesthetized with ketamine hydrochloride 20 mg•kg–1 and xylazine hydrochloride 5 mg•kg–1 intra-muscularly. The head was fixed in hyperextension while the body was in the supine position. The operative site was cleaned and shaved. A 6 to 7-cm incision was made transversely 2 cm above the sternal notch. The trachea was explored and suspended by retraction of the strap muscles. An incision was carried out with a bistoury between the 8th and 9th cartilaginous ring including the posterior membranous wall. No resection was performed. The dogs were randomly assigned to one of 3 groups of 6 dogs each. After control of the esophagus and near structures, the trachea was anastomosed with 3/0 Ethibond, 3/0 Vicryl, or 3/0 PDS. A suture was placed in each end of the membranous portion of the posterior tracheal wall and knotted outside. Other sutures were completed on the lateral and anterior medial line, according to tracheal size. Anastomoses required 5 to 8 sutures (mean, 6). Sutures were carefully passed from the intercartilaginous membrane above and under the anastomosis and all were knotted outside. Anatomic structures were closed with absorbable material after the anastomosis was completed. The mean operative time was 32 minutes. Cefotaxime 1 g was administered intramuscularly to all dogs in 3 doses at 2 days postoperatively.
Rigid bronchoscopy was performed under anesthesia 3 weeks after the procedure. The anastomosis lines were viewed by a video-bronchoscope. The dogs were killed 26 to 76 days (mean, 44 days) after the procedure with a high dose of intravenous thiopental sodium. The anastomosis lines were removed for histopathologic examination according to the evaluation times in the study of Friedman and colleagues.5 The bronchial anastomosis area was excised and fixed in 95% ethanol. Preparations were stained with hematoxylin and eosin and examined by light microscopy. Granulation tissue, fibrosis, and epithelization were evaluated to investigate differences in healing of the anastomosis lines. The scoring was: 0 = not observed, 1 = slight, 2 = moderate, and 3 = significant. Statistical analyses were performed using the Mann-Whitney U test. Statistical significance was defined as a p value of 0.05 or less.
|
Results
|
|---|
No complications or leakage from the anastomosis occurred in any of the dogs. When the anastomosis lines were viewed by video-bronchoscopy, suture materials were clearly observed in the nonabsorbable suture group, whereas those in the Vicryl group had started to become absorbed. The sutures in the PDS group were not yet showing absorption and the anastomosis line was normal. Macroscopic images of the specimens correlated with the bronchoscopic images (Figures 1 and 2
).
View larger version (147K):
[in this window]
[in a new window]
|
Figure 2. Granulation of the tracheal lumen at the anastomosis site (11th week in the Ethibond group).
|
|
Epithelial regeneration on the suture line was determined to be insufficient in the Ethibond group. Granulation tissue was observed in the tracheal sections from 5 of these 6 dogs. A tendency for suture rejection was observed in some sections and fibrosis was found in several areas (Figure 3). In the Vicryl group, epithelial regeneration was complete at 6 weeks. Suture material was seen to be absorbed in some areas of the preparations. The partial infiltration of polymorphonuclear leukocytes, which was observed at 3 weeks, had ceased by the 6th week (Figure 4). Good hydrolytic absorption occurred in the PDS group. Polymorphonuclear leukocyte infiltration was slight in 5 specimens and moderate in the other. There was moderate fibrosis on the suture line in the specimen with moderate infiltration. A significant difference in epithelization was noted between Ethibond and Vicryl sutures, and between Ethibond and PDS sutures (Table 1). There were no significant differences between the suture types when fibrosis and granulation tissue were evaluated.
View larger version (144K):
[in this window]
[in a new window]
|
Figure 3. Regeneration at the suture line was not easily visualized in the Ethibond group (hematoxylin and eosin stain, original magnification x100).
|
|
View larger version (130K):
[in this window]
[in a new window]
|
Figure 4. The suture line is covered by epithelium and the sutures are completely absorbed in the Vicryl group (hematoxylin and eosin stain, original magnification x100).
|
|
|
Discussion
|
|---|
Tracheoplastic procedures have been frequently applied to protect pulmonary function in selected malign and benign disorders in recent years. Experimental studies have indicated that stenosis may result from the use of nonabsorbable suture for tracheal anastomosis.2 Experi-mental and human studies have shown that synthetic absorbable sutures were superior to nonabsorbable sutures in preventing anastomosis stricture and suture reac-tions.2,3,5 Sezeur and colleagues6 concluded that poly-glycolic acid and braided polyglactin were not ideal but they were more advantageous than nylon or polypropylene. A study on dogs and rabbits showed that absorbable sutures caused less reaction and abscess formation than nonabsorbable material.7 Less granulation tissue has also been noted with nonabsorbable suture, although there was no difference between nonabsorbable polyester and absorbable chromic catgut.1,8–10 Similar histopathologic findings were obtained in this study where fibrosis and granulation tissue were significantly less with absorbable sutures compared to Ethibond. If nonabsorbable suture material must be used, subepithelial insertion is suggested to prevent the development of granulation tissue. Granu-lation tissue will heal as scar tissue and cause fibrous protrusions. Stricture is not usually important but a minor stricture may cause severe effects with consequent respiratory infection.
The drawbacks of a tight anastomosis with suture material that is resorbed within a few weeks are well known; diastasis and rupture may occur and fibrosis may cause stenosis. However, interrupted suturing with PDS was reported to be superior to other techniques in growing animals.3 PDS was noted to minimize inflammation after tracheal anastomosis in sheep.5 In our study, PDS caused less inflammation and produced minimal but resistant fibrosis. Approximating the ends of the anastomosis needs care because diastasis between the cartilages results in scar tissue that may narrow the tracheal lumen.11 Santoli and McKeown12 reported good long-term results after partial resection and anastomosis with nonabsorbable suture in a child with congenital tracheal aplasia. This study demonstrated that positive results can be obtained with a good surgical technique, regardless of the type of suture material. However, absorbable sutures such as Vicryl or PDS are recommended for tension-free anastomosis.
|
References
|
|---|
-
Har-El G, Chaudry R, Shaha A, Lucente FE. Resection of tracheal stenosis with end-to-end anastomosis. Ann Otol Rhinol Laryngol 1993;102:670–4.[Medline]
-
Hsieh CM, Tornita M, Ayabe H, Kawahara K, Hasegawa H, Yoshida R. Influence of suture on bronchial anastomosis in growing puppies. J Thorac Cardiovasc Surg 1988;95: 998–1002.[Abstract]
-
McKeown PP, Tsuboi H, Togo T, Thomas R, Tuck R, Gordon D. Growth of tracheal anastomoses: advantage of absorbable interrupted sutures. Ann Thorac Surg 1991; 51:636–41.[Abstract/Free Full Text]
-
Ray JA, Doddi N, Regula D, Williams JA, Melveger A. Polydioxanone (PDS), a novel monofilament absorbable suture. Surg Gynecol Obstet 1981;153:497–507.[Medline]
-
Friedman E, Perez-Atayde AR, Silvera M, Jonas RA. Growth of tracheal anastomoses in lambs. Comparison of PDS and Vicryl suture material and interrupted and continuous techniques. J Thorac Cardiovasc Surg 1990; 100:188–93.[Abstract]
-
Sezeur A, Leandry J, Rey P, Daumet P, Vouron J. Étude expérimentale du comportement des fils synthétiques à resorption lente dans les sutures tracheales. Ann Chir 1982;36:121–5.[Medline]
-
Sheele J, Gentrch HH, Hoffmann W, Pesch HJ. Anastomosentechnik an der Trachea. Laryugol Rhinol Otol (Stutg) 1982;61:107–14.
-
Nordin U, Chisen L. Prevention of tracheal stricture in end-to-end anastomosis. Arch Otolaryngol 1982;108:308–14.[Abstract/Free Full Text]
-
Maeda M, Grillo HC. Tracheal growth following anasto-mosis in puppies. J Thorac Cardiovasc Surg 1972;64: 304–13.[Medline]
-
Grillo HC, Zannini P, Michelassi F. Complications of tracheal reconstruction. Incidence, treatment, and prevention. J Thorac Cardiovasc Surg 1986;91:322–8.[Abstract]
-
Toomes H, Linder A. Mucociliary clearance following tracheal stricture in end-to-end anastomosis. Thorac Cardiovasc Surgeon 1989;37:277–80.[Medline]
-
Santoli E, McKeown PP. Nonabsorbable interrupted sutures for tracheal anastomosis in childhood [5]. Ann Thorac Surg 1992;53:1150–1.[Free Full Text]
TOP
Abstract
Introduction
