Suture Materials and Suture Selection for Use in Exotic Pet Surgical Procedures

Exotic animals are becoming increasingly popular and more exotic pet owners are seeking veterinary care. This has led to a demand for properly trained veterinarians who are capable of providing quality, up-to-date medical and surgical treatments. Many surgeries are now performed on exotic pets, and selection of the appropriate suture material is an important part of the treatment protocol. An understanding of different available suture materials, healing times of different tissues, and knowledge of different anatomic and physiologic characteristics in different species is important in the selection of the most appropriate suture material. This review will summarize important aspects of suture selection in exotic animals.     

Knot Security of Suture Materials

The knot security of chromic gut, polyglycolic acid, polyglactin 910, polydioxanone, polypropylene, and monofilament nylon size 2-0 suture materials were tested biomechanically in vitro. Twenty reproducible knots were tied and incubated in canine serum at 37 degrees for 24 hours before testing. A "secure knot" was defined as a knot that, when tested to failure, broke rather than untied by slippage. The minimum number of throws necessary to make a secure, snug (1500 g tension) square knot was three for gut, polyglycolic acid, polyglactin 910, and polypropylene and four for polydioxanone and nylon. All throws including the first were counted. With all suture materials tested, surgeon's knots were as secure as square knots. Only gut, polyglycolic acid, and polydioxanone granny knots were as secure as square knots; no loosely tied (500 g tension) asymmetric square knots were as secure as snug square knots, and only polydioxanone and polypropylene loose square knots were as secure as snug square knots. Square knots used to start a continuous pattern required one additional throw with gut, polydioxanone, and nylon. Square knots used to end a continuous pattern required two to three additional throws with all materials tested.     

Considerations for Selection of Suture Materials

The selection of a suture material, in the past, was based primarily on habit, guesswork and physical properties. This is understandable because there was a limited number of materials to select from and the interaction of suture material with tissues was not understood.     

Clinical Experience With Polydioxanone Suture Material

Polydioxanone (PDS™) synthetic absorbable suture material was evaluated in 169 dogs and cats. Sutures or ligatures were used on 446 tissues including 18 contaminated and 16 infected wounds. There was less tissue friction than with polyglycolic acid or polyglactin 910 sutures. The suture tended to kink during placement of continuous suture patterns. There was one wound dehiscence.
Polydioxanone may be used wherever surgical gut, polyglycolic acid, or polyglactin 910 sutures are normally used.     

Suture sinus in the linea alba of two dogs

Suture sinuses developed in the linea alba of two dogs, associated with monofilament, nonabsorbable suture material. Knot bulk and irritation was thought to be the most important factor in sinus development in one dog, while infection was thought the most important factor in the other dog. Both dogs responded to aggressive surgical resection of the affected tissue and the offending suture. The factors responsible for suture sinus formation and the management of such are discussed.     

一种自制缝合线的抗原性的实验研究

将大量肌腱缝合线溶液输入家兔耳静脉内,观察家兔的免疫反应,并分别取肌腱缝合线溶液、天然兔抗原、天然牛抗原皮下多点、腹腔、肌肉注射途径常规免疫家兔,来研究这三种抗原的免疫性强弱。结果发现,肌腱缝合线溶液的免疫反应性很弱。     

Suture exostosis with concurrent nasal septum chondrosarcoma in a horse

A 15‐year‐old Hanoverian mare presented with a 10‐day history of facial swelling in the right maxillary and frontal regions, left epiphora and intermittent right epistaxis. Radiographs revealed suture exostosis of both nasofrontal sutures and a deviated and thickened nasal septum. Computed tomography (CT) of the skull revealed exostosis of the nasolacrimal sutures and ducts bilaterally of both nasofrontal sutures and of the right zygomatocomaxillary and lacrimomaxillary sutures. The mid‐to‐caudal aspect of the nasal septum was thickened and had multiple well demarcated hypoattenuated regions within the septum. Histological examination of biopsies taken from the right nasofrontal suture and the nasal septal mass revealed suture exostosis and nasal septum chondrosarcoma. The horse was treated with rest and anti‐inflammatories. The facial swelling and left epiphora were improved at 7 months telephone follow‐up. This report is the first to describe a nasal septum chondrosarcoma in a horse. Additionally, we suggest that the suture exostosis may have developed due to an alteration of the biomechanics of the skull sutures secondary to the septal tumour.     

Suture materials: composition and applications in veternary wound repair

Suture materials play an important role in veterinary surgery by providing support for healing tissues during wound repair. As there is no single ideal suture material, clinicians must compromise on some properties when selecting a material for a specific purpose. By reviewing the characteristics of absorbable and non-absorbable materials, general recommendations can be made on their usage in skin, fascia, viscera and other tissues.     

Locking Loop Tendon Suture Use in Repair of Five Calcanean Tendons

The locking loop tendon suture is demonstrated. Five cases of its use in both acute and chronic lacerations of the calcanean tendon are presented. The results in all five cases were excellent. Advantages of this suture pattern include preservation of the intrinsic blood supply of the tendon, gap formation produced only with extreme load, simple and rapid placement of the suture, and reduction in adhesions. This suture pattern also can be used for other tendons.     

Suture exostosis causing obstruction of the nasolacrimal duct in three horses

CASE HISTORY Three horses were presented with facial swelling and epiphora.

CLINICAL FINDINGS: All horses had facial swellings and radiographic findings consistent with exostosis at the lacrimomaxillary suture, and ipsilateral epiphora. Positive contrast dacryocystorhinography demonstrated that the site of obstruction of the nasolacrimal duct was located where the duct traverses the lacrimomaxillary suture.

DIAGNOSIS: Lacrimomaxillary suture exostosis.

CLINICAL RELEVANCE: Lacrimomaxillary suture exostosis should be considered as a differential diagnosis in cases of epiphora in horses. Dacryocystorhinography, preferably retrograde and normograde, may be used as an aid to diagnosis.     

Mechanical Properties of Four Suture Patterns for Transected Equine Tendon Repair

Thirty-six superficial digital flexor tendons from nine fresh equine cadavers were transected and sutured with size 2 monofilament nylon. Nine tendons were repaired with each of four suture patterns: single-locking loop, double-locking loop, triple-locking loop, or three-loop pulley. The times required for application, tensile strengths, resistance to distraction (gap), and modes of failure were analyzed. The mean times required were: single-locking loop, 3 mins, 15 secs; double-locking loop, 4 mins, 15 secs; triple-locking loop, 10 mins, 50 secs; and three-loop pulley, 4 mins. The double-locking loop, triple-locking loop, and three-loop pulley suture patterns were stronger than the single-locking loop. The triple-locking loop and three-loop pulley patterns were close in strength and only the triple-locking loop was stronger than the double-locking loop. The three-loop pulley had the greatest resistance to gap formation and its mode of failure was different from the others. The three-locking loop suture patterns failed by suture breakage but the three-loop pulley failed first by suture pull-out and then by suture breakage.     

Response of Canine Synovial Membrane to Three Different Types of Suture Material

The synovial tissue response to three different suture materials was assessed in nine dogs. Stifle joint arthrotomies were sutured with either chromic gut, teflon coated polyester suture, or polypropylene suture; all joint capsule layers were penetrated, exposing the suture material to the joint cavity. The synoviocytic and subsynviocytic layers at the arthrotomy site were examined histologically one, two, and three weeks following surgery. Chromic gut caused the greatest cellular inflammatory response and polypropylene the least. Teflon coated polyester and chromic gut were associated with nearly the same degree of tissue fibrosis. Polypropylene was associated with much less fibrosis than the other suture materials.     

Strength Characteristics and Failure Modes of Suture Patterns in Severed Goat Tendons

The load-to-gap formation, maximum load, gap present at maximum load, and failure mode were compared among four suture patterns: Bunnell-Mayer, modified Kessler, Mason-Allen, and simple interrupted. Sixty-four goat tendons were sutured with 2-0 monofilament polypropylene in one of the patterns and distracted at 92 cm/min with an electrohydraulic materials testing system. All tests were filmed at 40 frames/sec with an intermittent pin registered camera. The load-to-gap formation was not significantly different among the Bunnell (13.3 +/- 1.5 newtons [N]), Kessler (12.8 +/- 1.3 N), and simple interrupted (11.7 +/- 1.7 N) patterns. The Mason-Allen pattern was significantly different )8.2 +/- 0.5 N). The Bunnell-Mayer had the highest mean maximum load to failure (43.0 +/- 1.6 N) followed by the modified Kessler (34.1 +/- 1.9 N). There was no difference between the Mason-Allen (22.9 +/- 1.4 N) and simple interrupted (21.2 +/- 1.4 N). All of the patterns permitted at least a 1 cm gap to form when the maximum load was applied. The Bunnell pattern caused severe constriction of the tendon and failed by suture material disruption. The modified Kessler caused some focal constriction, but the suture material pulled out before breaking and sliced the tendon in the process. The Mason-Allen and the simple interrupted patterns sliced the tendon as the suture pulled out of the tendon.     

Partial Maxillectomy in the Dog Comparison of Suture Materials and Closure Techniques

This study compares the healing of oronasal defects created by partial maxillectomy when closed using two different suture materials and two different suture patterns. In experiment 1, 24 dogs were divided into four equal groups. Partial maxillectomy was performed on each dog and was closed using either a two-layer simple interrupted suture pattern (12 dogs) or a modified Mayo mattress pattern (12 dogs) with either polyglactin 910 (12 dogs) or polypropylene (12 dogs) sutures. On the seventh postoperative day, the dogs were euthanized, suture line bursting pressures were measured, and wound healing was evaluated grossly and histopathologically. Suture line dehiscence occurred in one dog from each of the four groups. These were the only dogs in which electrocoagulation had been used. The healing of suture lines closed with the two-layer simple interrupted pattern was superior to that of those closed with the modified Mayo mattress pattern based on the degree of gross oral ulceration, suppurative inflammation, fibrosis and oral epithelial covering at the suture line, and the number of necrotic sites in the adjacent tissue. The healing of suture lines closed with polypropylene was superior to that of those closed with polyglactin 910 based on suture line bursting pressures and the degree of suppurative inflammation and tissue necrosis at the suture sites. In Experiment 2, partial maxillectomies were performed on four dogs, and closure was achieved using a two-layer simple interrupted suture pattern with either polyglactin 910 (two dogs) or polypropylene (two dogs). On the 30th postoperative day, the dogs were euthanized, and wound healing was evaluated grossly and histopathologically. All suture lines were well healed. All polyglactin 910 oral sutures were absent, while all polypropylene oral sutures were still present.