Cystotomy Closure: A Comparison of the Strength of Appositional and Inverting Suture Patterns

Dorsal cystotomies were performed in 60 healthy dogs. Twenty bladders were closed with a single-layer interrupted appositional suture pattern, 20 with a two-layer interrupted appositional suture pattern, and 20 with a two-layer continuous inverting suture pattern. Four dogs from each group were euthanatized at hours 0, 3, 12, 18, and 24. Mechanical strength of the cystotomy closures was evaluated by calculating the circular bursting wall tension. The single-layer interrupted appositional suture pattern was as strong as both two-layer suture patterns at hours 3, 12, 18, and 24. The two-layer interrupted appositional suture pattern was as strong as the two-layer continuous inverting suture pattern during the first 24 hours.     

In vitro bursting pressures of jejunal enterotomy closures in llamas

OBJECTIVE: To evaluate closure strength (in vitro bursting pressure) of jejunal enterotomies in llamas. STUDY DESIGN: In vitro experimental study. SAMPLE POPULATION: Jejunal specimens (n=72) from 6 llamas. METHODS: Differences in bursting pressures and luminal diameters were compared between 2 layer enterotomy closures with an initial full thickness simple continuous pattern oversewn with either a continuous Lembert or Cushing suture pattern using 3 sizes (2-0, 3-0, 4-0) of polyglactin 910 and polydioxanone. RESULTS: Bursting pressures were significantly higher for enterotomies closed with polydioxanone than polyglactin 910, independent of suture size, but there was no difference between Lembert and Cushing oversew patterns. Use of a Lembert pattern reduced intestinal diameter more than a Cushing pattern regardless of suture material or size. CONCLUSIONS: Although polydioxanone resisted higher bursting pressures than polyglactin 910, both suture materials should be considered satisfactory for jejunal enterotomy closure in llamas based on typical intraluminal pressures expected in clinical patients. The optimal oversew pattern may be continuous Cushing to maximize the luminal diameter in small intestinal enterotomy closures. CLINICAL RELEVANCE: In vitro bursting pressures may help to predict which enterotomy sites would leak post-operatively, although further studies are necessary to determine the outcome in clinical patients.     

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.     

Effects of Nylon and Polyglactin 910 Suture Material on Perilimbal Corneal Wound Healing in the Dog

The effects of fine suture materials on corneal wound healing in the dog were studied. In 20 dogs, standardized perforating perilimbal clear corneal wounds were made and closed with either monofilament Polyglactin 910 or nylon. Five dogs each were euthanized 8,12,16, and 21 days postoperatively. Results of gross, biomicroscopic, and histologic examinations at 8,12,16, and 21 days showed nylon and Polyglactin 910 to cause similar inflammatory responses. Epithelialization and suppuration around the suture tracts were observed more frequently when Polyglactin 910 was used. Both materials were associated with a foreign body (granulomatous) response. There was no loss of wound integrity with either material. Strengths of the incised corneal tissues with and without the sutures intact were determined. At day 16 postsurgery, there was a statistically significant difference in tissue strengths between cases in which sutures were and were not intact. This difference was not apparent at 21 days postsurgery, which suggested that the suture dependent phase ends between the 16th and 21st postsurgical days. In addition, at day 16 there was no statistical difference between the tissue strength of wounds sutured with nylon or Polyglactin 910. Corneal suture materials studied should remain in place for at least 16 days, and absorbable material is only appropriate if it retains tensile strength for 16 days.     

Esophagotomy Closure in the Dog A Comparison of a Double-Layer Appositional and Two Single-Layer Appositional Techniques

Esophagotomies were performed on 36 dogs and closed with 3-0 polydioxanone in double-layer simple interrupted, single-layer simple interrupted, or single-layer simple continuous patterns. The operative time was shortest for single-layer simple continuous closure, followed by single-layer simple interrupted and double-layer simple interrupted, respectively. Three dogs with each suture pattern were euthanatized at hours 0 and 1, and days 4 and 28 after surgery. The esophagotomy incisions were subjected to bursting strength testing and examined microscopically. The bursting wall tension was higher for all three suture pattern groups at 28 days than at 0 and 1 hour. The double-layer closure had higher bursting wall tension than the single-layer closures at 0 hour and 4 days. Single-layer simple continuous closure had the lowest bursting wall tension for each time period. Single-layer simple interrupted closure had the highest bursting wall tension at 28 days. Microscopic examination revealed close approximation of tissue planes for the double-layer closure and mucosal ever-sion for the simple interrupted and simple continuous single-layer closures. Healing was superior histologically with the double-layer closure.     

Tissue Reaction to Suture Material in the Feline Linea Alba A Retrospective, Prospective, and Histologic Study

Swelling and inflammation along the incision line were observed after elective ovariohysterectomy in 22 of 66 cats in a retrospective study. In a prospective study of 99 feline abdominal incisions closed with surgical gut, polyglactin 910, or polydioxanone, with and without subcutaneous closure, the least inflammation occurred when the linea alba was sutured with polyglactin 910 and the subcutaneous tissues were not sutured. Histologically, reactions in the linea alba of 12 other cats progressed from purulent to fibromononuclear to fibrous within 14 days after closure with gut, polyglactin 910, and polydioxanone. Microscopic evidence of seroma formation in 9 of 12 animals in which the subcutaneous tissue was not sutured suggested that surgical closure of subcutaneous dead space was indicated. The inflammatory reaction did not appear to be related to any one suture material as reactions were seen with all of them.     

Comparison of the healing of prescrotal urethrotomy incisions in the dog: sutured versus nonsutured

Comparison was made of the healing of sutured prescrotal urethral incisions (12 dogs) with that of nonsutured incisions (6 dogs). Comparison was also made of the healing of 5-0 polyglactin 910-sutured urethral incisions (6 dogs) with that of 5-0 polydioxanone-sutured incisions (6 dogs). Three dogs from each treatment group were euthanatized 3 weeks and 6 weeks after the surgical procedure. Surgical sites were examined grossly, and urethral circumference measurements were taken at 3 locations (surgical site, 1 cm cranially, and 1 cm caudally). Transverse sections of the surgical sites were prepared and examined by light microscopy. Hemorrhage occurred postoperatively in dogs in which the incisions were not sutured. The surgical sites from the 6 dogs in which incisions healed by second intention had more fibrosis and less inflammation than did those that were sutured. There was little difference between incisions sutured with polyglactin 910 and those sutured with polydioxanone suture material. Postoperative urethral stricture formation did not occur in any of the dogs.     

Pullout strength for three suture patterns used for canine tracheal anastomosis

OBJECTIVE: To compare pullout strength of 3 suture patterns used for canine tracheal anastomosis. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Cadaveric canine tracheae (n = 20). METHOD: Tracheal segments were anastomosed with 1 of 3 suture patterns: simple continuous, simple interrupted, and simple interrupted reinforced with horizontal mattress, each encircling annular cartilage rings adjacent to the transection site. Horizontal mattress sutures encircled the annular rings proximal and distal to the rings closest to the anastomosis. Each construct was distracted (0.5 mm/s) in a materials testing machine to failure. Load-displacement curves were generated and failure load (pullout strength) determined and mode of failure recorded. RESULTS: Tracheal anastomosis with a simple interrupted pattern was significantly weaker (mean+/-SD pullout strength, 102.55+/-30.14 N) than simple continuous (135.53+/-15.47 N) or simple interrupted plus horizontal mattress (132.39+/-21.46 N), which were not different from each other. Mode of failure was consistently by suture tear out. CONCLUSIONS: Both simple continuous and simple interrupted reinforced with horizontal mattress suture patterns have significant biomechanical advantage over a simple interrupted pattern alone in canine cadaveric tracheal anastomosis. The simple continuous pattern had the least variability in pullout strength. CLINICAL RELEVANCE: A simple continuous technique should be considered when selecting a tension-relieving pattern for canine tracheal anastomosis. It offers the same biomechanical advantage as a simple interrupted pattern reinforced with a horizontal mattress pattern and its strength appears to be reliably maintained when tested in canine cadaver tracheae.     

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.     

Comparison of gross and histologic tissue responses of skin incisions closed by use of absorbable subcuticular staples, cutaneous metal staples, and polyglactin 910 suture in pigs

OBJECTIVE: To assess gross and histologic tissue responses of skin incisions closed by use of absorbable subcuticular staples, cutaneous metal staples, and polyglactin 910 suture in pigs. ANIMALS: 8 purpose-bred disease-free pigs. PROCEDURE: Pigs were randomly allocated to 1 of 4 groups from which tissues were collected after death on postoperative days (PODs) 7, 14, 21, or 42. In each pig, 4 incisions were made; 1 was closed subcuticularly with 3-0 polyglactin 910 suture, 1 was closed with metal staples, and 2 were closed with absorbable subcuticular staples. Incision sites were grossly evaluated every 3 days after closure. At necropsy, incision sites and surrounding tissues were examined histologically; a histopathologic scoring system was used to quantitate healing and tissue response directed against the closure material. RESULTS: Postoperatively, the metal staples induced a severe inflammatory response, compared with minimal inflammation associated with the suture or absorbable subcuticular staples. Histologic evaluation of incisions on PODs 7, 14, and 21 revealed less severe inflammation associated with absorbable subcuticular staples than that associated with the other materials. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that absorbable subcuticular staples induced a less severe inflammatory response in the early stages of healing in pigs, compared with other commonly used methods of wound closure. Use of absorbable staples potentially combines the benefits of subcuticular closure with the speed and precision of staple placement.     

Comparison of incisional bursting strength of simple continuous and inverted cruciate suture patterns in the equine linea alba

OBJECTIVE: To determine the bursting strength of ventral median abdominal incisions closed by either simple continuous or inverted cruciate suture patterns. STUDY DESIGN: Experimental. ANIMAL OR SAMPLE POPULATION: Twelve equine cadavers. METHODS: A 25 cm ventral median incision was made through the linea alba and a 200 L polyurethane bladder was placed within the abdomen. Either a simple continuous or an inverted cruciate pattern using 3 polyglactin 910 with a bite size and suture interval of 1.5 cm was used to close linea incisions. Closure time was recorded for each pattern. The bladder was inflated with air at 40 L/min, and the pressure at body wall failure recorded. The length of suture used for wound closure and the wound failure modes were recorded. Deviation from the linea (cm), total suture length (cm), suture length to wound length ratio (SL:WL), closure time (min), bursting pressure (mm Hg), and failure modes were compared between groups using Welch-Aspin t-tests. The effects of independent subject variables were assessed for possible effects on bursting strength using analysis of covariance. RESULTS: Mean bursting pressure was significantly greater for the simple continuous pattern than for the inverted cruciate pattern (P = .01). Significantly less suture material (P = .0002) was required with the continuous pattern than with the inverted cruciate pattern. Mean closure time, SL:WL, deviation from the linea, and failure modes were not significantly different between groups. No significant effects were noted for independent variables in both groups on bursting strength. CONCLUSIONS: In this model, a simple continuous closure pattern for ventral median abdominal incisions was stronger than an inverted cruciate pattern. A simple continuous pattern leaves less foreign material in the wound, which may be of benefit in reducing incisional complications. CLINICAL RELEVANCE: Use of a continuous closure pattern for the linea alba may offer greater wound security during episodes of increased intra-abdominal pressure in horses.     

A Comparison of Three Techniques for Closure of Pelvic Flexure Enterotomies in Normal Equine Colon

Six enterotomies 3 cm long, spaced at 3 cm intervals, were made in the antimesenteric border of the pelvic flexure of the ascending colon in five adult horses. Ten incisions each were sutured with a Utrecht pattern (single layer), a full-thickness simple continuous oversewn with a Cushing pattern (two layer), and a mucosal simple continuous with a seromuscular simple continuous oversewn with a Cushing pattern (three layer). In all horses, chromic gut and polyglactin 910 were each used once for each pattern. On day 6, the pelvic flexure was excised and the colonic vessels were injected with a radio-opaque mass. Sections of each enterotomy were studied by light microscopy and high detail radiography. The single-layer closure led to serosa-to-mucosa healing and a thin bowel wall, and the three-layer closure resulted in distortion of the bowel wall by hematoma formation and submucosal contamination with ingesta. The two-layer closure resulted in good alignment and improved healing. There was less inflammatory reaction with polyglactin 910 than with chromic gut.     

Partial Maxillectomy and Premaxillectomy in the Treatment of Oral Neoplasia in the Dog and Cat

Partial maxillectomies were performed in 17 dogs and three cats to accomplish wide excision of oral tumors. The extent of the maxillectomy was dependent on tumor type, location, size, and invasiveness as determined by clinical and radiographic examination and incisional biopsy. The tumor and involved portions of adjacent facial bones, most commonly the maxillary and incisive bones, were removed. The resulting oronasal defect was closed by suturing a labial mucosal flap based on the lip margin to the hard palate mucoperiosteum. The major postoperative complication was partial suture line dehiscence, which occurred in three dogs. All four dogs with benign tumors were free of disease 7 to 34 months postoperatively (median 21.5 months). Of the 13 dogs treated for malignant neoplasia, seven were tumor-free at follow-up times ranging from 3 to 31 months (median 12 months). Five dogs with malignant tumors developed local recurrence 1 week to 10 months postoperatively (median 4.5 months). One cat with a benign tumor and two with malignant tumors were tumor-free at follow-up times of 7, 24, and 27 months. Partial maxillectomy can be effective in treating both benign and malignant oral tumors in dogs and cats.     

Reduction of diameter of the left ventricle of dogs by plication of the left ventricular free wall

OBJECTIVE: To determine effects of reducing the diameter of the left ventricle of dogs by plication of the left ventricular free wall. ANIMALS: 8 healthy adult mixed-breed dogs. PROCEDURE: Left lateral thoracotomy and a T-shaped pericardiotomy were performed. The free wall of the left ventricle was imbricated with 3 interrupted transfixing sutures applied in a horizontal mattress pattern, using 3-0 polypropylene suture assembled on a straight cutting needle. Surgeons were careful to avoid the coronary vessels. Echocardiography was performed 24 hours before and 48 hours after surgery. Electrocardiography was performed before and 1, 2, 7, 15, 21, 30, and 60 days after surgery. RESULTS: Echocardiographic measurements revealed that the diameter of the left ventricle was reduced by a mean of 23.5%. Electrocardiography revealed ventricular premature complexes 24 hours after surgery that regressed without treatment during the first week after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Plication of the left ventricular free wall of dogs can reduce end-diastolic and end-systolic dimensions of the left ventricle. The technique is simple and does not require cardiopulmonary bypass. According to Laplace's law, the reduction of cardiac diameter leads to reduction on free-wall tension and may improve left ventricular function in dilatated hearts. Thus, additional studies involving dogs with dilated cardiomyopathy should be conducted.     

Autogenous lamellar corneal grafting in dogs

Lamellar, autogenous, corneal grafts were performed on 9 clinically normal dogs (1 eye in each of 2 dogs and both eyes in each of 7 dogs) and 7 dogs with corneal disease (1 eye in each dog). Nylon, polyglycolic acid, polyglactin 910, and polydioxanone suture materials were used in 8-0 to 10-0 sizes. The eyes of the normal dogs were examined weekly for up to 16 weeks; corneal endothelium was reestablished in all eyes by 6 weeks after surgery. The eyes of the dogs with corneal disease were reexamined periodically for up to 9 months. Twenty-two of 23 (95.7%) grafts were considered successful in that they were translucent, and the dogs were able to see after surgery. The suture materials that caused the least tissue reaction were nylon and polyglactin 910. This procedure is indicated for chronic descemetoceles and other perforating corneal disease. It has the advantage of rapidly resolving severe corneal disease, with a high degree of success.     

Comparison of Adhesive Polyurethane Membrane and Polypropylene Sutures for Closure of Skin Incisions in Cats

Paired skin incisions were made on each side of four cats and closed with either interrupted polypropylene sutures or adhesive polyurethane membrane. The healing of these wounds was compared by gross appearance, break strength determination, and histologic examination. The adhesive polyurethane membranes were quicker and easier to apply, producing a more uniform closure than sutures both clinically and histologically. They adhered strongly to the skin, supporting more wound length than sutures for the first 7 days. There were no differences in break strength between closure techniques. Histologically, the wounds closed with adhesive polyurethane membrane were characterized by a milder inflammatory reaction and greater vascular infiltration than sutured wounds, especially early in the healing period.     

Closure of Abdominal Incisions Using A Continuous Polypropylene Suture: Clinical Experience in 550 Dogs and Cats

Closure of midline abdominal wall incisions in 469 dogs and 81 cats following various intraabdominal procedures was accomplished by using a single layer, simple continuous pattern with monofilament polypropylene. Skin was closed using simple interrupted nonabsorbable sutures. Weight of the patients ranged from 1 kg to 80 kg. Length of the incision ranged from 3 cm to 55 cm. There was one dehiscence (0.18%) and no incisional hernias. Results indicate the technique is a dependable, time saving method of abdominal closure.     

Comparison of Stainless Steel Fascial Staples and Polypropylene Suture Material for Closure of the Linea Alba in Dogs

Five centimeter segments of the linea alba in mature, female, mixed breed dogs were incised and then approximated with either stainless steel fascial staples or size 0 polypropylene suture material. Breaking strength of the linea alba closures was determined at 0 (Phase I, 18 dogs) and at 7,14, and 31 days (Phase II, 18 dogs). Histology and videointeractive planar morphometry were used to evaluate healing of the linea alba. Breaking strength and histologic and morphometric variables were analyzed statistically using analysis of variance in a split plot design. In a clinical trial, 20 cm linea alba incisions were approximated with stainless steel fascial staples after elective ovariohysterectomy in mature, female, mixed breed dogs (Phase III, eight dogs). The dogs were evaluated at 1, 2, 7,14, 31, 90, and 180 days. Linea alba incisions approximated with polypropylene suture material were significantly stronger than linea alba incisions approximated with stainless steel fascial staples on day 0. There was no significant difference between breaking strength values, histologic, and morphometric appearance of linea alba incisions closed with stainless steel fascial staples or polypropylene suture material when compared 7,14, and 31 days after surgery. All of the dogs in the clinical trial appeared to be normal at all evaluation times. Approximation of linea alba incisions with stainless steel fascial staples compares favorably to closure with a simple continuous pattern of polypropylene suture material with regard to breaking strength, clinical, histologic, and morphometric appearance.     

Comparison of a continuous suture pattern with a simple interrupted pattern for enteric closure in dogs and cats: 83 cases (1991-1997).

OBJECTIVE: To describe and compare a simple continuous suture pattern with a simple interrupted pattern for enterotomy closure or end-to-end intestinal anastomosis. DESIGN: Retrospective study. ANIMALS: 58 dogs and 25 cats that underwent enterotomy or intestinal resection and anastomosis. PROCEDURE: Signalment, surgical procedure, suture pattern, suture material, confirmation of dehiscence, and follow-up were reviewed. Groups were compared by procedure (anastomosis or enterotomy) and by suture pattern. RESULTS: 57 animals underwent continuous closure; 26 had interrupted closure. Only polydioxanone or polypropylene suture materials were used. Overall, 81 (98%) animals had no signs of intestinal dehiscence and survived > 2 weeks. Two animals had confirmed dehiscence after foreign body removal, 1 of 57 (2%) after continuous closure, and 1 of 26 (4%) after interrupted closure. CLINICAL IMPLICATIONS: The simple continuous closure pattern is an acceptable alternative to simple interrupted closure for small intestinal anastomosis or enterotomy closure.     

Reactions of goldfish (Carassius auratus) to three suture patterns following full thickness skin incisions

Three different suture patterns (simple interrupted, interrupted horizontal mattress, subcuticular) were placed in a full thickness incision (skin and body wall) of 18 goldfish (Carassius auratus). After 14 days all fish were euthanized using benzocaine solution. The tissue reactions were evaluated by gross visual inspection and histopathological examination. The superficial inflammatory reactions were graded on a scale from 0 (no inflammation) to 3 (severe inflammation). The inflammatory response in histological examination was graded on a scale from 0 (no inflammatory response or normal skin tissue) to 5 (severe inflammatory response and necrosis). The interrupted horizontal mattress induced a moderately severe to severe inflammatory response and necrosis (grades 4–5) but the subcuticular suture induced a very mild to mild inflammatory response (grades 0–1). The simple interrupted suture induced a moderate to moderately severe inflammatory response (grades 2–4). In conclusion, results showed that a subcuticular suture is the most appropriate to use in the closure of a full thickness body wall incision.