Chitosan thread in the healing of the cecal wall of rabbits (Oryctolagus cuniculus) submitted to cecorrhaphy

The development and evaluation of synthesis materials are crucial to reducing the morbidity and magnitude of post-enterorrhaphy surgical complications. Despite the possibility of production, chitosan thread has not yet been used in enterorrhaphy, and its effects on intestinal healing have not been evaluated. Therefore, this study aimed to evaluate the effects of chitosan thread on the intestinal wall repair of rabbits submitted to cecorrhaphy. For this, 42 rabbits were allocated into two groups with 21 animals. One group was submitted to cecorrhaphy with chitosan suture thread (CG) and the other with poliglecaprone suture thread (PG). The occurrence of postoperative complications, the intensity of edema, cellular response, formation of granulation tissue, as well as the deposition and maturation of collagen fibers, and the intensity of vascular endothelial growth factor (VEGF-α) expression, were evaluated during the intestinal wall repair process. The evaluations occurred on the 5th, 15th, and 25th postoperative (PO) days. The animals did not develop peritonitis, but adherence was observed in six animals from CG and seven from PG, with no difference between groups. The polymorphonuclear infiltrate showed higher intensity and higher amount of type III collagen fibers in CG on the 15th PO day. In contrast, a lower amount of type I collagen fibers was observed in CG samples on the 25th PO day. Therefore, the chitosan thread used for cecorrhaphy in rabbits results in minimal postoperative complications, presents biocompatibility, and bioactively assists the tissue repair process of the cecal wall, inducing minimal tissue reaction, stimulating the deposition of type III collagen fibers in the proliferative phase, with sustained VEGF-α expression, but with reduced deposition of type I fibers, indicating a delay in collagen maturation.

Evaluation of automated staple sizes on gastric layer incorporation and intraluminal pressure for partial gastrectomy closure in an ex vivo canine model

OBJECTIVE

To evaluate the performance of automated staple sizes on a cadaveric canine partial gastrectomy model.

METHODS

Stomachs were transected through the gastric body axis and randomly allocated to two closure groups: Group B, thoracoabdominal (TA) stapler 3.5 mm staple cartridge (blue); Group G, TA stapler 4.8 mm staple cartridge (green). After construct completion, leak testing was performed for both groups and compared. Initial leakage pressure (ILP), maximal leakage pressure (MLP) and leakage location were recorded. Staple lines were evaluated by direct observation and fluoroscopy to assess sub-mucosal layer incorporation and staple conformation. Staple shape was classified as optimal or suboptimal. Significance was set at p less than 0.5.

RESULTS

Following gastrectomy, the mean double gastric wall thickness was 7.82 ± 2.05 mm at the gastric body. Mean ILP was significantly lower in groups G (17.13 ± 1.19 mmHg) compared to group B (50.46 ± 6.03 mmHg, p = 0.0013). Similarly, mean MLP was significantly lower in group G (21.41 ± 1.39 mmHg) compared to group B (64.61 ± 10.21 mmHg, p < 0.0001). Although group G had higher percentage of B-shaped staple formation compared to group B, this was not significant (group G; 92.38%, group B; 54.56%; p = 0.054).

CONCLUSION

The 3.5 mm TA staple cartridge (blue) achieved superior bursting pressures compared with the 4.8 mm TA staple cartridge (blue) for the closure of a canine partial gastrectomy model. Both staple sizes incorporated all gastric layers. No differences were noticed in optimal staple conformation between groups. In vivo investigation is warranted to evaluate the use of different staple sizes on gastric tissue perfusion, successful healing and post-operative stasis and dehiscence.

Clinical outcomes of the use of unidirectional barbed sutures in gastrointestinal surgery for dogs and cats: A retrospective study

OBJECTIVE

To report the clinical outcomes of gastrointestinal surgery using unidirectional barbed sutures in single-layer appositional closure in dogs and cats.

STUDY DESIGN

Retrospective and descriptive study.

SAMPLE POPULATION

Twenty-six client-owned dogs; three client-owned cats.

METHODS

Medical records of dogs and cats that received gastrointestinal surgery closed with unidirectional barbed sutures were reviewed to collect information on signalment, physical examinations, diagnostics, surgical procedures, and complications. Short- and long-term follow-up information was collected from the medical records, the owners, or the referring veterinarians.

RESULTS

Six gastrotomies, 21 enterotomies, and nine enterectomies were closed with a simple continuous pattern with unidirectional barbed glycomer 631 sutures. Nine dogs had multiple surgical sites closed with unidirectional barbed sutures. None of the cases in the study developed leakage, dehiscence, or septic peritonitis during the 14-day short-term follow up. Long-term follow up information was collected for 19 patients. The median long-term follow-up time was 1076 days (range: 20-2179 days). Two dogs had intestinal obstruction due to strictures at the surgical site 20 and 27 days after surgery. Both were resolved with an enterectomy of the original surgical site.

CONCLUSION

Unidirectional barbed suture was not associated with a risk of leakage or dehiscence after gastrointestinal surgery in dogs and cats. However, strictures may develop in the long term.

CLINICAL SIGNIFICANCE

Unidirectional barbed sutures can be used during gastrointestinal surgery in client-owned dogs and cats. Further investigation of the role of unidirectional barbed sutures leading to abscess, fibrosis, or stricture is necessary.

An alternative asymmetric figure-of-eight single-layer suture technique for bowel anastomosis in an in vitro porcine model

Anastomotic techniques are of vital importance in restoring gastrointestinal continuity after resection. An alternative asymmetric figure-of-eight single-layer suture anastomotic technique was introduced and its effects were evaluated in an in vitro porcine model. Twelve 15-cm grossly healthy small intestine segments from a porcine cadaver were harvested and randomly divided into asymmetric figure-of-eight single-layer suture (figure-of-eight suture) and single-layer interrupted suture technique (interrupted suture) groups (n = 6 in each group). The anastomosed bowel was infused with methylene blue solution to test anastomotic leakage. Anastomosis construction time, leakage, and suture material cost were recorded and analyzed statistically using Fisher's exact test and Student's t-test. One anastomotic leakage occurred (16.67%) in the figure-of-eight suture group, and two (33.33%) in the interrupted suture group (p &gt; 0.9999). The anastomosis construction time was relatively short in the figure-of-eight suture group, but the difference did not reach a statistically significant level between the two groups. The mean number of suture knots and the cost of suture material in the figure-of-eight suture group were significantly decreased in comparison to the interrupted suture group (15.67 ± 3.30 vs. 22.17 ± 2.03, 167.11 ± 35.20 vs. 236.45 ± 21.70 CNY, p &lt; 0.01, respectively). Our results suggested that the alternative asymmetric figure-of-eight suture technique was safe and economic for intestinal anastomosis. An in vivo experiment is required to elucidate the effects of this suture technique on the physiological anastomotic healing process.

Influence of barbed suture oversew of the transverse staple line during functional end-to-end stapled anastomosis in a canine jejunal enterectomy model

Objective

To evaluate the influence of barbed suture oversew of the transverse staple line during functional end‐to‐end stapled anastomosis (FEESA) in dogs.

Study design

Randomized, experimental, ex vivo.

Animals or sample population

Grossly normal jejunal segments from 14 adult canine cadavers.

Methods

Ninety‐eight jejunal segments (n = 14/FEESA group, n = 14 controls) were harvested and randomly assigned to a control group, FEESA + monofilament suture oversew, FEESA + unidirectional barbed suture oversew or FEESA + bidirectional barbed suture oversew. Oversew techniques were performed using a Cushing suture pattern. Initial (ILP) and maximum leakage pressure (MLP), repair time (s), and location of observed leakage were recorded.

Results

No differences were detected in ILP (p = .439) or MLP (p = .644) respectively between experimental groups. Repairs times using barbed suture were ~ 18% faster (~25 s faster; p < .001) compared to monofilament suture. There was no difference between barbed suture types (p = .697). Mean ILP (p < .001) and MLP (p < .0001) were 6.6x and 5.1x greater respectively in the control group. Leakage location occurred predominately at the crotch of the FEESA in all groups.

Conclusion

FEESAs closed with a transverse staple line oversew using barbed suture, regardless of barb orientation, were completed faster and resulted in similar resistance to anastomotic leakage compared to monofilament suture.

Clinical significance

Oversewing the transverse staple line following FEESA using barbed suture offers similar resistance to anastomotic leakage, and may be associated with decreased surgical times in dogs compared to monofilament suture. Further studies are necessary to determine the benefits of barbed suture use in both open and laparoscopic gastrointestinal surgical applications following FEESA in dogs.

Influence of preconstructed effector loop location using a barbed unidirectional suture on leakage pressures following canine enterotomy closure

OBJECTIVE

To evaluate the influence of preconstructed effector loop location using a barbed unidirectional suture on leakage pressures following canine enterotomy closure.

STUDY DESIGN

Randomized, experimental, cadaveric.

ANIMALS OR SAMPLE POPULATION

Grossly normal jejunal segments from three canine cadavers.

METHODS

Jejunal segments were harvested and randomly assigned based upon effector loop location from the beginning of the incisional line. Groups (n = 12/group) included 0 mm, 5 mm, 10 mm, 15 mm, and intact controls (n = 6/group), repaired using a 3-0 unidirectional barbed suture in a simple continuous pattern. Initial leakage pressure (ILP), maximum intraluminal pressure (MIP), repair time, and leakage location were recorded.

RESULTS

Mean ILP for 0 mm group (24.42 ± 8.43 mmHg) was lower (p ≤ .001) compared to all experimental groups with ILP ~40% lower. There was no difference in MIP among experimental groups (p = .239). Repair time increased (p < .0001) as the distance of the effector loop increased ≥5 mm from the beginning of the incisional line. Leakage location differed among groups (p < .001) with leakage in the 0 mm group from the incisional line (75%), compared to leakage from predominantly from the suture holes in other groups, respectively.

CONCLUSION

Effector loop location influenced ILP and leakage location. Effector loops placed at the beginning of the incisional line (0 mm) decreased ILP compared to loops placed at 5, 10, and 15 mm.

CLINICAL SIGNIFICANCE

Effector loop location using a unidirectional barbed suture should be placed ≥5 mm from beginning of the incisional line for enterotomy closure. Further in vivo studies are necessary to determine the clinical significance of these findings.

Intraoperative surgeon probe inspection compared to leak testing for detecting gaps in canine jejunal continuous anastomoses: A cadaveric study

OBJECTIVE

To compare the detection of gaps in jejunal continuous anastomoses by probing (PT) versus leak testing (LT).

STUDY DESIGN

Experimental study.

ANIMALS

Normal jejunal segments (n = 24) from two fresh canine cadavers.

METHODS

Intestinal segments were randomly selected by four volunteers who created six simple continuous anastomoses: two constructs using standard technique with 2-3 mm suture spacing (ST, 8 total), and four constructs with one 4-mm gap (IG, 16 total). All 24 anastomoses were examined with PT (1 volunteer) prior to LT (3 volunteers). LT was performed within a maximal peristaltic pressure range (34-54 cmH₂ O). The presence and location of anastomotic leaks (L_A ) detected with LT were compared with gaps detected with PT.

RESULTS

Nineteen out of twenty-four (79.2%) samples had at least one probe drop, and four out of twenty-three (17.4%) samples leaked. LT results from one sample were excluded due to iatrogenic suture failure. PT was 100% sensitive (95% CI: 51.01, 100%) with a 100% negative predictive value (95% CI: 56.55, 100%) at detecting gaps compared with LT. The location of all L_A was accurately identified with PT and confirmed during LT.

CONCLUSION

PT was highly sensitive at detecting gaps compared with LT. All L_A were accurately detected by PT. None of the segments negative during PT leaked.

CLINICAL SIGNIFICANCE

The diagnostic value of PT appears adequate to recognize gaps in cadaveric small intestinal anastomoses. PT offers surgeons an alternative to detect suture gaps that may contribute to postoperative dehiscence of intestinal anastomoses.

Ex vivo comparison of hand-sutured versus circular stapled anastomosis in canine large intestine

OBJECTIVE

To compare leakage pressures of colonic anastomoses performed with circular staplers to conventional hand-sewn techniques in dogs.

STUDY DESIGN

Ex-vivo study.

ANIMALS

Colon from 11 canine cadavers.

METHODS

Thirty-two colonic anastomoses were performed. Four segments from each colon were randomly assigned to one of four techniques: hand-sewn colonic anastomoses performed with 4-0 glycomer 631 (G) and 4-0 barbed glycomer 631 (BG), and circular stapled colonic anastomoses using 4.8 mm End-to-End Anastomosis (EEA C4.8mm) and 3.5 mm End-to-End Anastomosis (EEA C3.5mm), 21 mm diameter circular staples in cadaveric canine colon. Leakage pressure was defined as the pressure at which dye-containing solution was first observed to leak from the anastomosis site.

RESULTS

Leakage pressures were 49.5 mmHg (range:16-72) in group G, 45.5 mmHg (range:19-80) in group BG, 5.3 mmHg (range:0-31) in group C3.5mm, and 29.5 mmHg (range:23-50.3) in group C4.8mm. Anastomoses leaked at lower pressures when stapled rather than hand-sewn (C4.8mm-G p = .0313, C4.8mm-BG p = .0131, C3.5mm-G p = .0469, C3.5mm-BG p = .0313). Two of the C3.5mm constructs leaked immediately after saline infusion with 4/6 leaking at <5.3 mmHg.

CONCLUSION

End-to-end colonic anastomoses closed with circular stapler leaked at lower pressures than hand-sutured anastomoses. Use of the EEA stapler with a staple height of 3.5 mm did not result in safe colonic anastomoses.

CLINICAL SIGNIFICANCE

These results provide evidence to support hand-suturing colonic anatomoses with G and BG in dogs. The 4.8 mm staples may be considered in anatomical locations difficult to reach.

Evaluation of barbed suture for celiorrhaphy and subcutaneous closure in bitches with pyometra submitted to ovariohysterectomy

Purpose

To evaluate the use of barbed sutures over the surgical time, the leukogram, the tissue thickness in which the sutures were employed (ultrasonography), the costs, and the possible complications in bitches with pyometra submitted to ovariohysterectomy (OH).

Methods

Convectional 2.0 polyglyconate suture was used in the control group (CG n = 10) and 2.0 barbed polyglyconate suture in the barbed group (BG n = 10) to perform celiorrhaphy (simple continuous pattern) and subcutaneous closure (continuous intradermal pattern). Data were assessed using paired (leukogram between 24 and 48 h within the same group) and unpaired (leukogram, surgical time, tissue thickness, and costs) Student’s t-test. The Fisher exact test was used to assess the occurrence of seroma between groups (p < 0.05). Results are shown as mean ± standard error of mean.

Results

The time spent to perform the celiorrhaphy (195.30 ± 17.37 s vs. 204 ± 16.00 s), subcutaneous closure (174.0 ± 15.86 s vs. 198.0 ± 15.62 s), and the total surgical time (24.30 ± 1.44 min vs. 23.00 ± 1.30 min) did not differ between BG and CG, respectively (p > 0.05). Leukogram at 48 h post-surgery did not differ between groups (p = 0.20). No differences were observed in the subcutaneous and the abdominal wall thickness (cm) assessed by ultrasonography at 48 h in BG (0.31 ± 0.04, 0.80 ± 0.05) and CG (0.34 ± 0.03, 0.72 ± 0.06), respectively. Similarly, 15 days post-surgery the same structures did not differ between BG (0.26 ± 0.02, 0.74 ± 0.08) and CG (0.26 ± 0.03, 0.64 ± 0.05) (p > 0.05). In one bitch from each group, a mild seroma was observed on one side of the surgical wound 48 h after surgery (p = 1.00). The procedures in which barbed sutures were used had an average additional cost of R$ 200.00 ± 11.66 (p < 0.0001).

Conclusions

Barbed suture has proven to be efficient and safe for abdominal and subcutaneous closure. However, considering its current high cost in addition thatthe surgical time of bitches with pyometra undergone OH was not reduced, no advantages were observed with theuse of barbed sutures for this type of surgery.

Comparison of a simple continuous versus simple interrupted suture pattern for the repair of a large, open duodenal defect with a jejunal serosal patch in a canine cadaveric model

OBJECTIVE

To determine whether jejunal serosal patches could securely seal large, open defects in duodenal segments harvested from canine cadavers and to compare intraluminal pressures at which leakage first occurred and maximal intraluminal pressures for repaired duodenal segments between 2 suture patterns.

SAMPLE

Duodenal and jejunal segments from 9 canine cadavers.

PROCEDURES

20 constructs were created through repair of large, open duodenal defects with circumferential suturing of an intact jejunal segment (jejunal serosal patch). Constructs were randomly assigned to have the serosal patch anastomosed to the duodenal segment by a simple continuous or simple interrupted suture pattern. The pressure at which the first leakage was observed and the maximum pressure obtained during testing were recorded and compared between suture patterns.

RESULTS

Initial leakage pressure was significantly higher with the simple interrupted pattern (mean ± SD, 68.89 ± 5.62 mm Hg), compared with the simple continuous pattern (59.8 ± 20.03 mm Hg). Maximum intraluminal pressures did not significantly differ between the simple interrupted (91 ± 8.27 mm Hg) and simple continuous patterns (90.7 ± 16.91 mm Hg). All constructs, regardless of suture pattern, withstood supraphysiologic pressures.

CONCLUSIONS AND CLINICAL RELEVANCE

Jejunal serosal patches adequately sealed large, open duodenal defects and prevented leakage in these constructs. Constructs with simple continuous or simple interrupted suture patterns withstood physiologic and supraphysiologic intraluminal pressures, although constructs with a simple interrupted suture pattern initially leaked at higher pressures. (Am J Vet Res 2020;81:985-991).

Comparison of intestinal leak pressure between cadaveric canine and commercial synthetic intestinal tissue that did and did not undergo enterotomy

OBJECTIVE

To compare initial leak pressure (ILP) between cadaveric canine and synthetic small intestinal segments that did and did not undergo enterotomy.

SAMPLE

Eight 8-cm grossly normal jejunal segments from 1 canine cadaver and eight 8-cm synthetic small intestinal segments.

PROCEDURES

Intestinal segments were randomly assigned to undergo enterotomy (6 cadaveric and 6 synthetic segments) or serve as untreated controls (2 cadaveric and 2 synthetic segments). For segments designated for enterotomy, a 2-cm full-thickness incision was created along the antimesenteric border. The incision was closed in a single layer with 4-0 suture in a simple continuous pattern. Leak testing was performed with intestinal segments occluded at both ends and infused with dilute dye solution (999 mL/h) until the solution was observed leaking from the suture line or serosal tearing occurred. Intraluminal pressure was continuously monitored. The ILP at construct failure was compared between cadaveric and synthetic control segments and between cadaveric and synthetic enterotomy segments.

RESULTS

Mean ± SD ILP did not differ significantly between cadaveric (345.11 ± 2.15 mm Hg) and synthetic (329.04 ± 24.69 mm Hg) control segments but was significantly greater for cadaveric enterotomy segments (60.77 ± 15.81 mm Hg), compared with synthetic enterotomy segments (15.03 ± 6.41 mm Hg).

CONCLUSIONS AND CLINICAL RELEVANCE

Leak testing should not be used to assess the accuracy or security of enterotomy suture lines in synthetic intestinal tissue. Synthetic intestinal tissue is best used for students to gain confidence and proficiency in performing enterotomies before performing the procedure on live animals.

Gastrointestinal thickness, duration, and leak pressure of six intestinal anastomoses in dogs

OBJECTIVE

To compare leak pressures and construct completion time of six intestinal anastomoses and report normal canine gastrointestinal thickness.

STUDY DESIGN

Experimental study.

ANIMALS

Grossly normal jejunal segments (n = 140) from 10 fresh canine cadavers.

METHODS

Gastrointestinal thickness was recorded. Eight-centimeter cooled canine cadaveric jejunal segments were randomly assigned to a control group (20 segments) and six treatment groups (20 segments/group [10 constructs/group]): (1) handsewn anastomosis (HSA), (2) functional end-to-end stapled anastomosis (FEESA)-blue thoracoabdominal (TA; FEESA-TAB), (3) FEESA-green TA (FEESA-TAG), (4) FEESA TA-gastrointestinal anastomosis (GIA), (5) FEESA with suture oversew (FEESA-O), and (6) skin staples (SS). Construct assembly time, initial leak pressure (ILP), maximum intraluminal pressure (MIP), and leakage location were compared.

RESULTS

Initial leak pressures (mean ± SD) for control (308.38 ± 115.91 mm Hg), HSA (41.96 ± 15.97), FEESA-TAB (31.71 ± 15.71), FEESA-TAG (27.24 ± 14.11), FEESA-GIA (25.62 ± 11.22), FEESA-O (31.01 ± 17.38), and SS (44.42 ± 28.88) groups were compared. No difference in ILP (P > .24) or MIP (P > .17) was detected between treatment groups. Sutured anastomoses took up to 10 times longer to complete (P = .0025). The stomach, duodenum, jejunum, and ileum mural thicknesses (mean ± SD) were 3.99 ± 0.44 mm, 2.34 ± 0.16, 2.49 ± 0.28, and 2.30 ± 0.31, respectively.

CONCLUSION

The ILP of all anastomoses exceeded maximum intraluminal peristaltic pressures. Stapled anastomoses were faster to complete.

CLINICAL SIGNIFICANCE

All anastomoses may be considered when performing an intestinal resection and anastomosis, with stapled anastomoses resulting in a shorter surgical time. Canine intestinal thickness may warrant use of a larger staple size.

Effect of presurgical storage conditions on leakage pressures of enterotomy sites closed with unidirectional barbed suture material in fresh, chilled, and frozen-thawed cadaveric canine jejunal specimens

OBJECTIVE

To evaluate the effect of presurgical storage conditions on leakage pressures of enterotomy sites closed with unidirectional barbed suture material in fresh, chilled, and frozen-thawed cadaveric canine jejunal specimens.

SAMPLE

36 grossly normal jejunal segments obtained from 4 dog cadavers.

PROCEDURES

9 jejunal segments were harvested immediately from each euthanized dog and randomly assigned to be tested within 4 hours after collection (fresh segments), stored at 4°C for 24 hours before testing (chilled segments), or stored at -20°C for 7 days and thawed at 21°C for 6 hours before testing (frozen-thawed segments). For leakage pressure testing, a 3-cm-long antimesenteric enterotomy was performed and repaired with 3-0 unidirectional barbed suture material in a simple continuous pattern in each segment. Time to complete the enterotomy, initial leakage pressure, maximum intraluminal pressure, and leakage location were recorded for each segment.

RESULTS

Mean ± SD initial leakage pressure for fresh, chilled, and frozen-thawed segments was 52.8 ± 14.9 mm Hg, 51.8 ± 11.9 mm Hg, and 33.3 ± 7.7 mm Hg, respectively. Frozen-thawed segments had significantly lower mean initial leakage pressure, compared with findings for fresh or chilled segments. Time to complete the enterotomy, maximum intraluminal pressure, and leakage location did not differ among groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Leak pressure testing of cadaveric jejunal segments that are fresh or chilled at 4°C for 24 hours is recommended for enterotomy studies involving barbed suture material in dogs. Freezing and thawing of cadaveric jejunal tissues prior to investigative use is not recommended because leak pressure data may be falsely low.

A Review of Normal Intestinal Healing, Intestinal Anastomosis, and the Pathophysiology and Treatment of Intestinal Dehiscence in Foreign Body Obstructions in Dogs

Small intestinal anastomoses are commonly performed in veterinary medicine following resection of diseased or devitalized intestinal tissue. Traditionally, suture has been employed to anastomose intestinal ends. However, use of intestinal staplers has become increasingly popular due to the ability to produce a rapid anastomosis with purported superior healing properties. Under normal conditions, intestinal healing occurs in three phases: inflammatory, proliferative, and maturation. Dehiscence, a devastating consequence of intestinal anastomosis surgery, most often occurs during the inflammatory phase of healing where the biomechanical strength of the anastomosis is almost entirely dependent on the anastomotic technique (suture or staple line). The resulting septic peritonitis is associated with a staggering morbidity rate upwards of 85% secondary to the severe systemic aberrations and financial burden induced by septic peritonitis and requirement of a second surgery, respectively. Intraoperative and postoperative consideration of the multifactorial nature of dehiscence is required for successful patient management to mitigate recurrence. Moreover, intensive postoperative critical care management is necessitated and includes antibiotic and fluid therapy, vasopressor or colloidal support, and monitoring of the patient's fluid balance and cardiovascular status. An understanding of anastomotic techniques and their relation to intestinal healing will facilitate intraoperative decision-making and may minimize the occurrence of postoperative dehiscence.

Influence of oversewing the transverse staple line during functional end-to-end stapled intestinal anastomoses in dogs

OBJECTIVE

To determine the effect of oversewing the transverse staple line after functional end-to-end stapled intestinal anastomoses (FEESA) on canine jejunal leakage pressures.

STUDY DESIGN

Experimental, ex vivo, randomized study.

SAMPLE POPULATION

Jejunal segments from three adult canine cadavers.

METHODS

Jejunal segments were harvested within 2 hours of euthanasia and anastomosed (24 jejunal segments per group, consisting of two segments per construct with n = 12/ group). Constructs were then randomly assigned to receive FEESA alone, FEESA + Cushing oversew, or FEESA + simple-continuous oversew of the transverse staple line with 3-0 polydioxanone. Results for initial leakage pressure (ILP) and maximal leakage pressure (MLP) and initial leakage location (LL) were compared between groups.

RESULTS

Mean ILP was 1.8-fold higher for FEESA + Cushing oversew (62.4 ± 7.8 mm Hg) compared with FEESA alone and FEESA + simple-continuous oversew (P < .001). Mean MLP were higher for both oversewn techniques compared with FEESA alone (P < .001). Oversewing the transverse staple line with either pattern increased mean MLP by 1.4-fold compared with FEESA alone. Leakage occurred at the level of the transverse staple line in nonoversewn constructs (P < .001).

CONCLUSION

Oversewing the transverse staple line after FEESA increased MLP and decreased the occurrence of leakage at this location. Oversewing with a Cushing pattern increased ILP compared with oversew with a simple-continuous pattern.

CLINICAL SIGNIFICANCE

Our results provide evidence to support oversewing the transverse staple line after FEESA. Doing so may reduce the occurrence of postoperative dehiscence. These findings warrant additional focused investigation in vivo through a prospective randomized clinical trial.

Ex vivo comparison of leakage pressures and leakage location with a novel technique for creation of functional side-to-side canine small intestinal anastomoses

OBJECTIVE

To determine the ability of functional side-to-side small intestinal anastomoses (FSS-SIA) created with an electrothermal bipolar vessel sealing (EBVS) device to resist leakage.

STUDY DESIGN

Experimental, ex vivo.

SAMPLE POPULATION

Jejunal segments (n = 130) from 10 healthy canine cadavers.

METHODS

Four types of anastomoses were created (two segments/construct and 15 constructs/group): EBVS (group A), EBVS + transverse stapling (group B), stapled (group C), and EBVS + suture augmentation (group D). Initial leakage pressure (ILP), initial leakage location (ILL), and maximal intraluminal pressure were compared between groups, and five group A constructs were analyzed histologically.

RESULTS

Initial leakage pressure was greater in group D than in groups A, B, and C (P < .011). There was a difference in ILL among groups (P = .003). Leakage occurred at the side-to-side intestinal anastomosis fusion line in 13 of 15 (87%) constructs for groups A and B and in nine of 15 (60%) constructs for group D. Maximal intraluminal pressure was greater in group C than in groups A, B, and D (P < .004). Histological examination was consistent with collagenous fusion without cavitation defects.

CONCLUSION

Functional side-to-side small intestinal anastomosis was consistently achieved with an EBVS device. Augmentation of EBVS anastomoses with simple interrupted sutures along the anastomotic fusion line increased ILP compared with stapled anastomoses.

CLINICAL SIGNIFICANCE

Despite the success and feasibility of creating an FSS-SIA with an EBVS device, additional in vivo studies are required to determine the effectiveness of intestinal fusion prior to clinical implementation.

Influence of closure technique on leakage pressures in an ex vivo canine typhlectomy model

OBJECTIVE

To determine the influence of three closure techniques on leakage pressures of canine typhlectomies.

STUDY DESIGN

Experimental, ex vivo.

SAMPLE POPULATION

Grossly normal cecal segments from 24 adult canine cadavers.

METHODS

Typhlectomies were assigned to one of three closure techniques: simple continuous closure with a Parker-Kerr pattern with 4-0 polydioxanone (group 1), closure with a 60-mm gastrointestinal stapler loaded with a 3.8-mm staple cartridge (group 2), and placement of a Cushing suture to augment the stapled closure (group 3). The median (range) of initial leakage pressure (ILP) and maximum leakage pressure (MLP) was compared between groups along with leakage location.

RESULTS

Typhlectomies in group 3 leaked at higher ILP (310 mm Hg; 188-310) than those in groups 1 (43 mm Hg; 31-80) and 2 (109.5 mm Hg; 68-173; P < .0001). Maximum leakage pressure were greater in group 3 than in other groups (P < .0001). Leakage was detected in 20 of 24 (83%) typhlectomies, located at the incisional line in 13 of 24 (54%) specimens and from suture holes in seven of 24 (29%) specimens.

CONCLUSION

Placement of a Cushing suture pattern to augment stapled incisions improved the ability of typhlectomies to sustain pressure compared with sutured or stapled cadaveric specimens alone.

CLINICAL SIGNIFICANCE

These results provide evidence to support placement of a Cushing suture pattern to augment the staple line for typhlectomies in dogs, although in vivo studies are required to determine the clinical significance of these findings.

Initial leak pressures of four anastomosis techniques in cooled cadaveric canine jejunum

OBJECTIVE

To compare the effectiveness of four different intestinal anastomosis techniques at preventing leakage after enterectomy.

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Grossly normal jejunal segments (N = 70) from three fresh canine cadavers.

METHODS

Eight-centimeter cooled canine cadaveric jejunal segments were randomly assigned to a control group (six segments) and four treatment groups (16 segments each [two segments/anastomotic construct]): (1) handsewn anastomosis (HSA), (2) barbed suture anastomosis (B-HSA), (3) stapled functional end-to-end anastomosis (SFEEA), and (4) stapled functional end-to-end anastomosis with an oversew (SFEEA-O). Control segments and anastomotic constructs were infused intraluminally to the point of leakage. Initial leak pressures were recorded and compared.

RESULTS

Initial leak pressures (median + range) for jejunal control segments, HSA, B-HSA, SFEEA, and SFEEA-O were 331.88 mmHg (range, 315.34-346.64), 35.17 (20.29-56.24), 24.99 (6.08-38.64), 28.77 (18.80-85.09), and 35.92 (12.05-80.71), respectively. No difference was detected between leak pressures of anastomosed segments (P = .35), all of which were more variable and lower than those of intact segments.

CONCLUSION

No difference in initial leak pressures was detected between the four anastomosis techniques tested in cooled canine cadaveric jejunum.

CLINICAL SIGNIFICANCE

All four anastomosis techniques evaluated in this study may be suitable in dogs.

Ex vivo comparison of the effect of storage temperature on canine intestinal leakage pressures

OBJECTIVE

To determine the effect of storage temperature on cadaveric small intestinal leakage pressures after enterotomy.

STUDY DESIGN

Experimental ex vivo study.

ANIMALS

Grossly normal jejunal segments from four canine cadavers.

METHODS

Thirty-six jejunal segments (n = 12 segments/group) were harvested immediately after euthanasia and assigned to a fresh group (tested within 4 hours), chilled group (stored for 24 hours at 4°C before testing), or freeze-thaw group (frozen at -20°C for 7 days and thawed at 21°C for 6 hours before testing). A 2-cm antimesenteric enterotomy was performed and repaired with 4-0 monofilament suture in a simple-continuous pattern. Initial leakage pressure (ILP), maximal intraluminal pressure (MIP), and leakage location were recorded, with testing performed at room temperature.

RESULTS

Mean ± SD ILP for fresh, chilled, and frozen-thawed specimens was 52.9 ± 8.4, 51.8 ± 11.9 and 29.8 ± 4.4 mm Hg, respectively. There was a difference in ILP among groups (P < .003), with freeze-thaw samples demonstrating lower ILP compared with other groups. There was no difference in MIP between groups (P = .186) There was a difference in leakage location among groups (P = .004), with the majority of chilled and freeze-thaw samples leaking at the suture holes compared with the incisional line in fresh samples.

CONCLUSION

Freezing and subsequent thawing prior to specimen testing reduced ILP compared with use of fresh and chilled specimens but did not affect MIP among experimental groups.

CLINICAL SIGNIFICANCE

Cadaveric canine intestinal specimens tested immediately after collection or after chilling for 24 hours should be recommended for ex vivo burst pressure assessment in dogs. Additional studies to evaluate loss in testing viability of chilled intestinal specimens are warranted to help govern experimental methodologies.

The use of bidirectional barbed suture in the treatment of a complete common calcanean tendon rupture in a dog: Long-term clinical and ultrasonographic evaluation

The canine common calcanean tendon can be repaired successfully using a modified Kessler knotless barbed technique. A long-term ultrasound follow-up showed improved and increased normal tendon fibrillar echotexture and homogeneity.

Effects of needle gauge and syringe size on small intestinal leakage at injection sites

OBJECTIVE

To determine the influence of needle gauge, syringe volume, and syringe size on needle tract leakage after injection in porcine jejunum.

STUDY DESIGN

Ex vivo experiment.

SAMPLE POPULATION

Three hundred sixty jejunal segments from 20 feedlot pigs.

METHODS

Fresh porcine intestines were divided into 5-cm or 10-cm segments and randomly assigned to the one of nine treatment groups: 25-gauge, 22-gauge, and 20-gauge needles attached to full 12-mL, half-full 20-mL, and full 20-mL syringes (n = 20/group). The jejunal segments were occluded with Rochester-Carmalt forceps prior to injection of diluted India ink. Injection time and leakage were noted by a blinded observer. Multivariate analysis was used with segment size, needle gauge, volume infused, time to inject per milliliter, and syringe size as variables.

RESULTS

Leakage occurred in 36% of 5-cm and 15% of 10-cm segments and was immediate without palpation in 33.8% and 11% of segments, respectively. Protective effects were seen for 22-gauge needles in both 5-cm (P = .002) and 10-cm (P = .001) segments, whereas injection of 20 mL had a higher odds ratio of leakage compared with injection of 10 mL and 12 mL in 5-cm segments (P = .003).

CONCLUSION

Injections with 22-gauge needles reduced the frequency of leakage, while 20 mL instilled in 5-cm segments increased the frequency of leakage in intact segments of porcine jejunum.

CLINICAL SIGNIFICANCE

Injection with a smaller syringe size attached to a 22-gauge needle through a 10-cm segment of small intestine may lower the frequency of leakage from the injection site, but influence on the detection of surgical site leakage remains unknown.

Comparison of two different barbed suture materials for end-to-end jejuno-jejunal anastomosis in pigs

BACKGROUND

Hand-sewn intestinal anastomoses are a fundamental procedure in both open and laparoscopic intestinal surgery. Self-retaining barbed suture devices have been tested for a variety of surgical applications. With the exception of clinical reports and various experimental studies on enterotomy, little has been published so far on the use of barbed suture for end-to-end intestinal anastomoses. The aim of the study was to compare two different barbed suture materials for end-to-end jejuno-jejunal anastomosis in pigs. End-to-end jejuno-jejunal anastomosis were performed with unidirectional barbed (A group), bidirectional barbed (B group) or normal (C group) sutures in each animal. A comparison was then made between the groups based on adhesions scoring, suturing time, bursting pressure and histopathology.

RESULTS

Mean construction times in the A group (518 ± 40 s) and in the B group (487 ± 45 s) were significantly lower than in the C group (587 ± 63 s) but were not different between A and B group (P = 0.10). Mean bursting pressures were significantly higher in the intact intestine (197 ± 13 mmHg) than in any other group (group A 150 ± 16 mmHg, group B 145 ± 22 mmHg, group C 145 ± 24 mmHg). Among anastomotic techniques, the bursting pressures were not significantly different. Histologically no difference could be detected in the grade of inflammation, collagen deposition and neovascularization at the anastomotic sites.

CONCLUSIONS

Barbed sutures can be effectively used for handsewn end-to-end jejunojejunal anastomosis in pigs. They are comparable to normal suture but could provide a shorter surgical time.

Biomechanical analysis of unidirectional knotless suture loop weld integrity after passage through a cadaveric body wall

OBJECTIVE

To evaluate the integrity of the welded end loop on unidirectional knotless suture after transabdominal passage in a canine cadaver.

STUDY DESIGN

Ex vivo biomechanical study.

STUDY POPULATION

Four variations of unidirectional knotless suture and 1 canine cadaver.

METHODS

Welded end loop on strands consisted of 0 Quill polydioxanone (QP; n = 22), 0 Quill monoderm (QM; n = 23), 2-0 V-Loc 90 (V9; n = 12), and 2-0 V-Loc 180 (V18; n = 12). Half of the suture strands in each group were passed percutaneously through an insufflated cadaveric body wall, and the remaining half served as intact controls. A linear testing machine was used to load the sutures to failure. Modes of and loads to failure were compared within and between suture types.

RESULTS

Loads to failure did not differ between sutures passed through the body wall and their controls when the loop remained intact. Sutures V9, V18, and QM sustained higher loads to failure compared with QP. All Quill suture lines failed at the weld during testing. Thirty-three percent of QP sutures failed at the weld during initial passage through the body wall. V-Loc sutures failed at the suture-apparatus interface, within the welded loop, or a combination.

CONCLUSION

Passing suture through a cadaveric body wall did not affect the integrity of the welded end loop of any of the unidirectional knotless sutures tested here when the loop remained intact.

CLINICAL SIGNIFICANCE

Unidirectional knotless suture (V9, V18 and QM) can be safely passed through a canine body wall for use in laparoscopic procedures. The use of QP in this manner cannot be recommended.

A Comparison of Ex Vivo Leak Pressures for Four Enterotomy Closures in a Canine Model

Initial and maximum intraluminal leak pressures of four enterotomy closures were compared. Closure patterns included a modified Gambee, simple interrupted, simple continuous, and skin staple closure. Forty-eight 3-cm enterotomy constructs were created from jejunal segments harvested from 12 dogs. Twelve each were randomly assigned to the four closure methods. Time of closure, as well as initial and maximum leak pressures, were measured and compared. The modified Gambee closure was the slowest closure to perform, with skin staple closure being the fastest. All suture patterns tested had higher mean initial leak pressures than reported physiologic intestinal pressures during peristalsis, although the skin staple closures resulted in leakage below normal physiologic pressure in several samples. The modified Gambee closure was able to sustain a significantly higher initial leak pressure than skin staple closures. The modified Gambee suture pattern had the greatest maximum leak pressure of all enterotomy closure patterns tested. Use of the modified Gambee suture pattern should be considered in enterotomy closure, although in vivo studies are required to determine if these differences are clinically significant.

Ex vivo biomechanical comparison of barbed suture and standard polypropylene suture for acute tendon laceration in a canine model

Objectives: Evaluate performance and resistance to gap formation of a non-absorbable, barbed, monofilament suture, in comparison with a non-absorbable, smooth, monofilament polypropylene suture, in two different suture patterns: three-loop pulley (3LP) and modified Bunnell-Mayer (BM).

Sample size: Seventy-two medium-sized cadaveric superficial digital flexor muscle tendon units.

Methods: After manual transection and suture repair, individual specimens were placed in an electromechanical tensile testing machine and tested to monotonic failure using tensile ramp loading. Video data acquisition allowed evaluation of failure mode and quantification of gap formation.

Results: Incidence of gap formation between tendon ends was significantly greater in tenorrhaphies repaired with barbed suture compared to those repaired with smooth polypropylene. Use of a 3LP suture pattern caused significantly less gapping between tendon ends when compared to the BM pattern.

Conclusion: Smooth polypropylene suture was consistently superior in load performance than a unidirectional barbed suture. The 3LP pattern was more resistant than a BM pattern at preventing gap formation.

Clinical significance: Smooth polypropylene should be recommended over barbed unidirectional suture for use in canine tendinous repair to provide increased resistance to gap formation. The 3LP is superior to the BM suture pattern, requiring significantly more force to cause tenorrhaphy gap formation and failure, which may translate to increased accrual of repair site strength and tendinous healing in clinical situations.