Comparison of three suture techniques for anastomosis of the small intestine in the horse

Seven horses were used to compare the Gambee, the crushing, and a 2-layer inverting suture pattern composed of a simple continuous layer in the mucosa oversewn with a continuous Lembert pattern in the seromuscular layer. Horses were evaluated at 30 days for adhesion formation, lumen diameter, and quality of healing at the anastomotic sites. One horse was euthanatized 9 days after surgery after 24 hours of ileus and colic; necropsy revealed septic peritonitis and widespread adhesions. One horse had no adhesions. The remaining horses had adhesions associated with 50% of the Gambee and 50% of the crushing anastomoses. There were no adhesions related to the 2-layer inverting techniques in these 6 horses. There was no significant difference in percentage reduction of lumen diameters between the 3 techniques, and there was no evidence of chronic obstruction resulting from any of the anastomotic techniques. Histologically, the inflammatory response and fibrosis were minimal in the single layer patterns, but there was increased fibrosis and suture tract inflammation in the 2-layer inverting technique.     

Evaluation of three techniques for end-to end anastomosis of the small colon in horses

In an attempt to determine the best method for surgical removal of devitalized small colon lesions, 12 horses underwent a double small colon resection and end-to-end anastomosis. In 4 horses (study 1), an appositional single-layer (APP-1) suture pattern was compared with an inverting 2-layer (INV-2) suture pattern. In 8 horses (study 2), an appositional 2-layer (APP-2) suture pattern was compared with the INV-2 suture technique. Polydioxanone suture (size 1-0), was used. Horses were evaluated at necropsy 3, 10, 14, 28, or 56 days after surgery. Postoperative complications (peritonitis, impaction, or excessive adhesions) were encountered in 100, 42, and 13% of the APP-1, INV-2, and APP-2 anastomoses, respectively. Postmortem evaluation of the small colon revealed dehiscence of the anastomotic site, diffuse peritonitis, and adhesion formation in 3 of the 4 horses in which the resection line was closed with the APP-1 pattern. With the INV-2 and APP-2 techniques, more intestinal inversion was present in the nontaenial than in the taenial portion of the small colon. More postoperative impactions were found with the INV-2 (n = 5) anastomoses than with the APP-2 (n = 1) technique; this appeared to be the result of excessive tissue inversion. There was no difference in lumen diameter between the INV-2 and the APP-2 techniques (P greater than or equal to 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of a hyaluronate membrane for jejunal anastomosis in horses

OBJECTIVE: To compare the outcomes of double-layer inverting anastomosis (DIA), single-layer anastomosis (SLA), and single-layer anastomosis combined with a hyaluronate membrane (SLA+HA-membrane) with respect to stomal diameter, adhesion formation, surgery time, and anastomotic healing in horses. ANIMALS: 18 adult horses. PROCEDURE: Midline celiotomy and end-to-end anastomoses were performed. In control horses (n = 6), DIA was performed; in treated horses, SLA was performed (6) or SLA+HA-membrane was performed (6). Horses were euthanatized 21 days after surgery. Abdominal adhesions were evaluated grossly and histologically. Stomal diameters were measured ultrasonographically and compared with adjacent luminal diameters. Anastomotic healing was evaluated histologically for fibrosis and inflammation, tissue alignment, and inversion. Surgery times were recorded for the anastomotic procedure and compared among groups. RESULTS: There were significantly more adhesions in the SLA group, compared with the DIA and SLA+HA-membrane groups. Reduction in stomal diameters in the DIA group was significantly greater than the SLA and SLA+HA-membrane groups. Surgery times for the DIA group were significantly greater than the SLA and SLA+HA-membrane groups. Histologic findings of fibrosis, inflammation, and mucosal healing were similar among groups. There was significant tissue inversion in the DIA group, compared with the 2 treatment groups. Tissue alignment was not different among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Use of a SLA+HA-membrane was an effective small intestinal anastomotic technique. This technique was faster to perform and resulted in a larger stomal diameter, compared with the DIA technique and significantly fewer perianastomotic adhesions, compared with the SLA technique.     

Effect of carboxymethylcellulose and hyaluronate solutions on jejunal healing in horses

OBJECTIVE: To compare a double-layer inverting anastomosis with a single-layer appositional anastomosis, coated with either 1% sodium carboxymethylcellulose (SCMC) or 0.4% sodium hyaluronate (HA) solutions, in the small intestine of horses with respect to anastomotic healing and adhesion formation. ANIMALS: 18 adult horses. PROCEDURE: Midline celiotomy and end-to-end jejunal anastomoses were performed. In control group horses (n = 6), a double-layer inverting anastomosis coated with sterile lactated Ringer's solution was performed. In treatment group horses, a single-layer appositional anastomosis was performed that was coated with 1% carboxymethylcellulose solution (SAA + SCMC group horses, 6) or 0.4% hyaluronate solution (SAA + HA group horses, 6). An additional 500 mL of the respective treatment solution was applied to the jejunal serosal surface, and 2 jejunal serosal abrasion sites were created. Horses were euthanatized 10 days after surgery. Anastomoses and abdominal adhesions were evaluated grossly. Anastomotic healing was evaluated on the basis of bursting wall tension. RESULTS: Bursting wall tension was significantly greater in SAA + SCMC group horses, compared with control group horses. All intestinal segments failed at a point distant to the anastomosis. Significantly fewer adhesions were found at the abrasion sites of SAA + HA group horses, compared with control group horses. No differences were found in adhesion formation at the anastomotic sites among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Coating a single-layer appositional jejunal anastomosis with SCMC or HA solutions does not adversely affect anastomotic healing. Application of 0.4% HA solution to the serosal surface of the jejunum significantly decreases the incidence of experimentally induced intra-abdominal adhesion formation in horses.     

Comparison of suture materials and suture patterns for inverting intestinal anastomosis of the jejunum in the horse

In 7 horses, 4 anastomoses were done in the small intestine in each, using the combinations of synthetic absorbable monofilament and multifilament suture materials with continuous- and interrupted-suture patterns in the serosubmucosal layer of a 2-layer inverting-suture technique. Horses were evaluated 30 days after the operation for adhesion formation, lumen diameter, evidence of chronic obstruction, and suture tract inflammation at the anastomosis. Postoperative obstruction occurred in 5 of the 7 horses, and 6 horses survived. One horse was euthanatized on postoperative day 6 after 48 hours of ileus and obstruction; necropsy revealed a partial intussusception involving the anastomosis done with continuous multifilament-suture material. Two other horses that became obstructed between postoperative days 3 and 5 had protracted ileus and gastric reflux up to 48 hours' duration, but survived. Horses that had obstruction after the 6th postoperative day recovered within 4 hours of onset. The continuous inverting-suture pattern in the serosubmucosal layer resulted in significantly (P less than 0.05) fewer adhesions than did the interrupted pattern, and suture material had no effect on adhesion formation. There was no significant difference in the percentage of reduction of lumen diameter between the variations of the 2-layer technique, and there was no evidence of chronic obstruction related to any of the anastomoses. Suture tract inflammation was moderate in the anastomoses, using continuous-multifilament suture, with neutrophils being the predominant cell type. The anastomoses with continuous-monofilament suture had mild inflammation with focal accumulations of neutrophils. Minimal inflammation was associated with both types of suture in the interrupted pattern.     

Evaluation of Intestinal Staples for End-to-end Anastomosis of the Small Intestine in the Horse

Segments of jejunum that had been subjected to ischemia 1 month previously were resected en bloc in six horses. Everted end-to-end anastomoses were performed by application of double rows of stainless steel staples. The anastomotic sites were examined at 3 weeks, 3 months, 6 months, and 8 months postoperatively. All but one of the horses experienced colic at some point after the second postoperative week. At 3 weeks, there was extensive adhesion and stricture formation associated with the anastomoses. With increasing time postoperatively, there were progressively less severe adhesions and strictures. At 6 and 8 months, there was separation of the muscularis with noticeable thinning at the anastomotic site.     

Partial Arytenoidectomy in the Horse with and without Mucosal Closure

Left-sided partial arytenoidectomy was performed in eight horses to evaluate healing. Four horses underwent conventional partial arytenoidectomy with suture apposition of the mucosa. In four horses, most of the arytenoid cartilage, including overlying mucosa, vocal fold, and laryngeal saccule, were excised en bloc without mucosal closure. The horses were monitored clinically by endoscopic examination. One horse from each group was euthanatized at weeks 2, 4, 8, and 16. Complete necropsies with gross and histologic examination of the arytenoidectomy sites were performed. Postoperative complications such as coughing, dysphagia, and aspiration pneumonia were not encountered and problems with wound healing were minimal in both groups. The defect created by partial arytenoidectomy without mucosal closure initially filled to the level of the luminal surface with granulation tissue, with a gradual transition to mature fibrous connective tissue. Grossly, the defect appeared to be healed and was completely epithelialized by week 16 without apparent narrowing of the laryngeal lumen. Partial arytenoidectomy sites with mucosal closure healed in a similar pattern by week 8. Partial dehiscence of the dorsal portion of the sutured mucosa occurred in three horses.     

One percent sodium carboxymethylcellulose prevents experimentally induced abdominal adhesions in horses

OBJECTIVE--To evaluate the efficacy of 1% sodium carboxymethylcellulose (SCMC) for prevention of experimentally induced abdominal adhesions in horses. STUDY DESIGN--Prospective, controlled, experimental study. ANIMAL POPULATION--Twelve healthy adult horses. METHODS--The effect of 1% SCMC on adhesion formation was evaluated in 12 healthy horses by using an established model of serosal trauma to induce intraabdominal adhesions. After ventral median celiotomy, 2 separate areas of the jejunum were abraded, and three 2-0 chromic gut sutures were placed in each abraded area. Jejunal resection and end-to-end anastomosis was performed at 2 sites distant to the abrasion sites. In treated horses (n = 6), 2 L of 1% SCMC was applied to the intestine before and after intestinal manipulation. In control horses (n = 6), 2 L of saline solution were applied to the intestine before and after surgical manipulation. All horses were euthanatized 10 days after surgery, and the abdominal cavity was evaluated for adhesion formation. The frequency of intraabdominal adhesions between groups was compared with a chi-square test. Statistical significance was set at P <.05. RESULTS--All control horses had intraabdominal adhesions. Fibrous adhesions were associated with both jejunal abrasion sites in 5 control horses. Fibrous adhesions were also associated with 1 or both jejunal anastomotic sites in 5 control horses. Only 1 treated horse developed adhesions at the jejunal abrasion sites, and no adhesions were present at the anastomotic sites in the treated horses. There were significantly fewer adhesions in the SCMC treatment group compared with the control group (P <.05). CONCLUSION--In this experimental model, application of 1% SCMC reduced the frequency of intraabdominal adhesions at areas of serosal abrasion and at jejunal anastomotic sites. CLINICAL RELEVANCE--In horses at an increased risk for developing intraabdominal adhesions after intestinal surgery, the use of 1% SCMC during celiotomy may decrease the frequency of adhesion formation.     

Colopexy of the Left Large Colon to the Right Large Colon in the Horse

Three colopexy techniques were examined in 11 normal horses to determine which would prevent recurrence of targe colon displacement and volvulus. The medial free band of the left ventral colon was sutured to the medial free band of the right ventral colon (technique A). The free band of the left dorsal colon was sutured to the free band of the right dorsal colon (technique B). In technique C, both the ventral and dorsal colon were sutured as in techniques A and B, and the pelvic flexure was sutured to the mesocolon between the right dorsal and right ventral colon. Absorbable (surgical gut) and nonabsorbable (polypropylene) suture material were compared.
One horse from each group was euthanized 2 weeks and 6 months after surgery. The position of the colon and the integrity of the colopexy were examined. At necropsy, attempts were made to produce displacement and volvulus of the colon. In the remaining horses, exploratory celiotomy 1 year after surgery was used to examine the integrity of the colopexy.
Although all horses initially lost weight after surgery, all but one began gaining weight 2 to 4 weeks later and had attained their preoperative weight by 6 months. The horse that continued to lose weight was euthanized 2 months after surgery. Numerous small colon, omental, and large colon adhesions were found at necropsy.
For all colopexy techniques, the colopexy adhesion remained short and intact at polypropylene suture sites. At surgical gut sites, the adhesion had lengthened by 6 months and was absent at 1 year. At necropsy, all colopexies prevented manual displacement of the large colon and volvulus of the colon at the sternal and diaphragmatic flexures. The colopexies did not prevent manual creation of volvulus at the base of the colon. Technique A was the easiest to perform.     

Effects of sodium hyaluronate on tendon healing and adhesion formation in horses

Sodium hyaluronate reduces adhesions after tendon repair in rodents and dogs, and has been used in limited clinical trials in people. To evaluate its effect on tendon healing and adhesion formation in horses and to compare these effects with those of a compound of similar visco-elastic properties, a study was performed in horses, using a model of collagenase injection in the flexor tendons within the digital sheath. Eight clinically normal horses were randomly allotted to 2 groups. Adhesion formation between the deep digital flexor tendon and the tendon sheath at the pastern region was induced in the forelimbs of all horses. Using tenoscopic control, a 20-gauge needle was inserted into the deep digital flexor tendon of horses under general anesthesia and 0.2 ml of collagenase (2.5 mg/ml) was injected. The procedure was repeated proximally at 2 other sites, spaced 1.5 cm apart. A biopsy forceps was introduced, and a 5-mm tendon defect was created at each injection site. Group-A horses had 120 mg of sodium hyaluronate (NaHA) gel injected into the tendon sheath of one limb. Group-B horses had methylcellulose gel injected at the same sites. The contralateral limbs of horses in both groups served as surgical, but noninjected, controls. Horses were euthanatized after 8 weeks of stall rest. Ultrasonographic evaluation revealed improved tendon healing after NaHa injection, but no difference in peritendinous adhesion formation. Tendon sheath fluid volume and hyaluronic acid (HA) content were greater in NaHA-treated limbs. Gross pathologic examination revealed considerably fewer and smaller adhesions when limbs were treated with NaHA. However, significant difference in pull-out strengths was not evident between NaHA-treated and control limbs. Histologically, the deep digital flexor tendon from the NaHA-treated limbs had reduced inflammatory cell infiltration, improved tendon structure, and less intratendinous hemorrhage. Treatment with methylcullulose had no significant effect on tendon healing, adhesion size, quantity, or strength or on the volume and composition of the tendon sheath fluid. Sodium hyaluronate, administered intrathecally, appears to have a pharmaceutically beneficial action in this collagenase-induced tendinitis and adhesion model in horses.     

ANGIOGRAPHIC EVALUATION OF BOVINE INTESTINAL HEALING FOLLOWING INVERTING, EVERTING, AND END-ON ANASTOMOSIS

Angiography during intestinal healing following single-layer inverting, everting, and end-on anastomoses was carried out in 18 calves. Six anastomoses using the same technique were performed in each animal. Six anastomoses, along with one main artery supplying the anastomotic site, were removed from each calf on the first, third, seventh, 15th, 21st, and 28th postoperative days. Angiograms of tubular intestinal segments were obtained after intraarterial infusion of 2–3 ml of sodium iothalamate and lead suspension. Lead-infused intestinal segments were cut open through the mesenteric border to obtain additional angiograms of flat bowel. Angiograms in the early stage of intestinal healing revealed hypervascularity at the cut edges and an avascular zone at the suture line. These changes were more intense with the everting than with the inverting and end-on techniques. The sprouting of vessels at the anastomotic junction and their crossing over started on third postoperative day but were clearly visualized only after the seventh postoperative day. By 15–21 days after operation, anastomotic sites were almost completely revascularized for all techniques. Everted anastomosis elicited more intense vascular response and resulted in earlier vascularization than the other two techniques. No appreciable differences in the pattern of revascularization were observed with inverting and end-on anastomoses. Lead suspension proved to be better than sodium iothalamate for such studies. Angiograms of the open bowel provided more realistic and confirmatory information regarding the sequence of vascular-changes at the suture line.     

Closed One-Stage Functional End-to-End Jejunojejunostomy in Horses With Use of Linear Stapling Equipment

Objective—To use gastrointestinal linear stapling instrumentation to perform a closed one-stage functional end-to-end jejunojejunostomy in adult horses as an alternative to a stapled side-to-side jejunojejunostomy.
Study Design—Clinical outcome, anatomic and histological architecture, and anastomotic dimensions were determined at 2, 4, 8, 16, and 24 weeks postoperatively. Animals or Sample Population—18 adult horses.
Methods—The anastomosis and peritoneal cavity were inspected for adhesions. The diameter and circumference of the anastomosis and jejunum oral and aboral to the anastomosis were determined from digitized contrast radiographs and linear measurements. Healing of anastomotic sites was evaluated histologically.
Results—Three horses were euthantized in the immediate postoperative period. In the 15 surviving horses, there were no peritoneal adhesions or distortion of the anastomoses and stomas remodeled in an end-to-end fashion. The mean anastomotic staple line (7.48 cm) and mucosa (6.89 cm) diameters were significantly ( P < .05) larger than the mean jejunal diameter oral (6.03 cm) and aboral (6.01 cm) to the anastomosis. The mean anastomotic luminal circumference (13.61 cm) was significantly ( P < .01) larger than the mean oral (11.43 cm) and aboral (11.12 cm) jejunal circumference. Histologically, there was adequate mucosal and muscularis mucosae reapposition with a moderate degree of fibrosis and inflammation.
Conclusions —Closed one-stage functional end-to-end jejunojejunostomy resulted in an acceptable functional anastomosis.
Clinical Relevance —This technique appears to be an acceptable alternative to linearly stapled, side-to-side jejunojejunostomies performed in horses.     

The effect of compacted cancellous bone grafting on the healing of subchondral bone defects of the medial femoral condyle in horses

Objective— To compare the quality of second-intention healing and that of compacting sternally harvested cancellous bone into subchondral bone defects of the medial femoral condyle in horses.
Study Design— A controlled experiment using a surgical technique that minimizes soft tissue trauma, customized for consistency among horses.
Animals or Sample Population— Ten horses, aged 2 to 5 years, free of hindlimb lameness and with radiographically normal stifles.
Methods— After a 12.7-mm-diameter × 19-mm-deep defect was created into randomly selected medial femoral condyles, bone and cartilage healing was evaluated over a 6-month period in control horses (  n = 5  ) and horses receiving a compacted cancellous bone graft (  n = 5  ). Healing was evaluated using lameness assessment, radiographic and microradiographic interpretation, arthroscopic appearance, percent bone fill, proteoglycan content, and histology.
Results— Six months after surgery, there was no significant difference between grafted and ungrafted defects with respect to lameness, radiographic score, or percent bone fill. Histologically, grafted defects were characterized by the presence of dead graft and secondary cyst formation in four defects. Ungrafted defects filled with fibrous tissue and no cyst formation were identified.
Conclusions— Grafted defects do not heal better than ungrafted defects, and lameness was not affected by surgical technique.
Clinical Significance— Cartilage healing is similar in grafted and ungrafted defects in the equine medial femoral condyle at 6 months, suggesting that surgical debridement alone of cystic structures remains the treatment of choice.     

Strangulated umbilical hernias in horses: 13 cases (1974-1985)

The medical records of 13 horses with strangulated umbilical hernias were reviewed. Typical history included increased swelling, warmth, and firmness of the hernial sac. Enterocutaneous fistulas had developed in 2 horses. Four horses had signs of abdominal pain. Surgery was performed on all horses, and the hernia was reduced by an open reduction technique. Incarcerated tissue included omentum (1 horse), jejunum (5), ileum (4), cecum (1), and ventral colon (2). All horses survived and were discharged from the hospital. Follow-up information on 9 horses (5 to 52 months after discharge) revealed no complications in 6 horses. Of the remaining 3 horses, one horse was euthanatized 5 months after discharge because of laminitis. One horse had persistent drainage from the skin incision requiring removal of nonabsorbable suture material 8 months after discharge. One foal required a second surgery because of signs of abdominal pain 17 days after the initial surgery. The foal was euthanatized during surgery because of severe peritonitis secondary to anastomotic leakage.     

Use of a linear stapling device to construct an inverted, triangulated, end-to-end anastomosis of the equine jejunum

An inverting, triangulated, stapled, end-to-end anastomosis technique was evaluated in the jejunum of four horses. None of the horses showed evidence of gastrointestinal disturbance after surgery; however, stricture and adhesion formation were pronounced in three animals examined 10 days, one month, and two months after surgery. The animal examined four months after surgery had no adhesions present at the anastomosis, and only mild narrowing of the intestinal lumen. Histologic examination of the anastomoses showed lack of a normal mucosal lining in some examined sections up to two months postsurgery. While mucosal and serosal continuity were eventually reestablished, this was not true of the muscularis, the ends of which were joined by fibrous tissue. Gaps in the staple line and malalignment of staples were present in the animal examined four months after surgery, indicating migration and/or loss of the staples from the anastomosis. The inverting, triangulated staple technique had little or no apparent advantages over previously reported results with similar everting techniques. The severity of adhesions observed with the inverting technique suggests that the adhesions observed with the similar everting technique may not be due solely to the everted nature of the anastomosis.     

Healing characteristics of deep digital flexor tenorrhaphy within the digital sheath of horses

OBJECTIVE: To describe the healing characteristics of deep digital flexor tenorrhaphy within the digital sheath. STUDY DESIGN: Experimental study. ANIMALS: Five mature horses. METHODS: Right thoracic limb, deep digital flexor tenorrhaphy was performed within the digital sheath. Limbs were cast in partial flexion using a short limb cast for 6 weeks. Next, extended heel shoes were used for limb support for 14 weeks. Healing was evaluated by sequential ultrasonographic examinations, and limb use was evaluated by force plate analysis. At 26 weeks, mechanical strength and morphologic characteristics of the repair site were evaluated. RESULTS: Gap (mean, 0.93 cm.) formation was evident in unloaded limbs at 3 weeks. This increased markedly by 6 weeks and was 5 cm at 26 weeks. Demarcation between the deep and superficial flexor tendons decreased as the transected ends adhered to the dorsal surface of the superficial flexor tendon. The intrathecal space was reduced by fibrous tissue. Mean maximum load to failure of the repair tissue was 4,616 +/- 3,556 N, with a mean stress of 12.99 +/- 2.78 MPa. The repair consistently failed at the adhesion between the transected tendon and the superficial flexor tendon. CONCLUSIONS: Intrathecal tenorrhaphy with external coaptation (in partial limb flexion) for 6 weeks resulted in gap healing, fibrous adhesion between the deep and superficial flexor tendons, fibrous tissue reduction of the intrathecal space, and a pasture-sound horse at 26 weeks. CLINICAL RELEVANCE: Without improved methods for immobilizing the deep digital flexor tendon, intrathecal tenorrhaphy is unlikely to result in first intention tendon healing.     

Incisional Hernias in the Horse Incidence and Predisposing Factors

Medical records of 210 horses that survived ventral midline celiotomy for at least 4 months were examined and owners were queried to determine factors contributing to incisional hernia formation. The incidence rate of incisional hernias within 4 months was 16%. Factors significantly associated with occurrence of incisional hernias were incisional drainage, closure of the linea alba with chromic gut suture material, previous midline celiotomy, excessive incisional edema, castrated male sex, postoperative leukopenia, and postoperative pain (colic). Factors not significantly associated with occurrence of incisional hernias were suture pattern used for linea alba closure, concurrent enterotomy or intestinal resection, postoperative bandage or stent, postoperative fever, hypoproteinemia, diarrhea, respiratory disease (coughing), and peritonitis. Hernias developed in horses within 12 weeks of surgery, with the earliest hernia recognized at week 2. Of 30 horses for which information was available, only one hernia developed in 24 (80%) and two or more hernias developed in 6 (20%) along the incision. Multiple hernias tended to be smaller than single hernias.     

Foreign body attachment to polypropylene suture material extruded into the small intestinal lumen after enteric closure in three dogs

Three dogs in which polypropylene suture material was used to close an enteric surgery site in a continuous pattern were evaluated at a later date because of recurrence of signs of intestinal disease. Surgery in each dog revealed that the suture material had been extruded into the lumen of the intestine and acted as a site for attachment of a foreign body. The nonabsorbable nature of polypropylene and its use in a continuous pattern are possible explanations for this complication. Polydioxanone or poliglecaprone 25 may be suitable alternatives to polypropylene for use in a continuous pattern for closure of small intestinal surgery sites.     

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.