One percent sodium carboxymethylcellulose prevents experimentally induced abdominal adhesions in horses

HOPX+ injury-resistant intestinal stem cells drive epithelial recovery after severe intestinal ischemia

Intestinal ischemia is a life-threatening emergency with mortality rates of 50%-80% due to epithelial cell death and resultant barrier loss. Loss of the epithelial barrier occurs in conditions including intestinal volvulus and neonatal necrotizing enterocolitis. Survival depends on effective epithelial repair; crypt-based intestinal epithelial stem cells (ISCs) are the source of epithelial renewal in homeostasis and after injury. Two ISC populations have been described: 1) active ISC [aISC; highly proliferative; leucine-rich-repeat-containing G protein-coupled receptor 5 (LGR5⁺)-positive or sex-determining region Y-box 9 -antigen Ki67-positive (SOX9⁺Ki67⁺)] and 2) reserve ISC [rISC; less proliferative; homeodomain-only protein X positive (HOPX⁺)]. The contributions of these ISCs have been evaluated both in vivo and in vitro using a porcine model of mesenteric vascular occlusion to understand mechanisms that modulate ISC recovery responses following ischemic injury. In our previously published work, we observed that rISC conversion to an activated state was associated with decreased HOPX expression during in vitro recovery. In the present study, we wanted to evaluate the direct role of HOPX on cellular proliferation during recovery after injury. Our data demonstrated that during early in vivo recovery, injury-resistant HOPX⁺ cells maintain quiescence. Subsequent early regeneration within the intestinal crypt occurs around 2 days after injury, a period in which HOPX expression decreased. When HOPX was silenced in vitro, cellular proliferation of injured cells was promoted during recovery. This suggests that HOPX may serve a functional role in ISC-mediated regeneration after injury and could be a target to control ISC proliferation.NEW & NOTEWORTHY This paper supports that rISCs are resistant to ischemic injury and likely an important source of cellular renewal following near-complete epithelial loss. Furthermore, we have evidence that HOPX controls ISC activity state and may be a critical signaling pathway during ISC-mediated repair. Finally, we use multiple novel methods to evaluate ISCs in a translationally relevant large animal model of severe intestinal injury and provide evidence for the potential role of rISCs as therapeutic targets.

Effects of hyaluronate-carboxymethylcellulose membranes on the clinical outcome of horses undergoing emergency exploratory celiotomy

OBJECTIVE

To determine the influence of hyaluronate-carboxymethylcellulose (HA-CMC) membranes applied to intestinal anastomoses or enterotomies on postoperative complications after emergency exploratory celiotomy.

STUDY DESIGN

Multicenter retrospective case-controlled series.

ANIMALS

Adult horses (59 in the HA-CMC group and 91 controls).

METHODS

Medical records from 4 referral hospitals were searched for horses ≥1 year of age, treated between 2008 and 2014 with emergency exploratory celiotomy, and surviving at least 24 hours postoperatively. Horses receiving repeat celiotomy during the same hospitalization were excluded. Horses who received HA-CMC were matched with controls who did not receive HA-CMC but had similar intestinal lesions and procedures at the same referral hospital. Postoperative complications (colic, nasogastric reflux, fever, incisional infection, and septic peritonitis), duration of hospitalization, and survival were compared between groups. Data were compared between horses by t test, Wilcoxon signed rank test, and χ² test.

RESULTS

The volume of nasogastric reflux at admission (P = .02) and the duration of administration of lidocaine after surgery (P = .02) were greater in horses with HA-CMC membranes than in controls. No difference in postoperative complications or survival was detected between groups: 48 of 59 (81%) horses treated with HA-CMC survived until discharge from the hospital compared with 80 of 91 (88%) horses in the control group (P = .27). Fifteen of 21 horses treated with HA-CMC and 30 of 43 horses in the control group survived >12 months after hospital discharge.

CONCLUSION

Application of HA-CMC membranes to anastomoses or intestinal incisions did not influence postoperative complications or survival after emergency celiotomy compared with controls.

CLINICAL SIGNIFICANCE

The safety and efficacy of HA-CMC membrane application to intestinal sites during colic surgery in horses is equivocal.

Evaluation of the reasons for and outcomes of gastrointestinal tract surgery in pet pigs: 11 cases (2004-2015)

OBJECTIVE To evaluate the reasons for and outcomes of gastrointestinal tract surgery in pet pigs. DESIGN Retrospective case series. ANIMALS 11 pigs. PROCEDURES The medical record database of a teaching hospital was searched to identify pet pigs that underwent at least 1 celiotomy because of a possible gastrointestinal tract obstruction between 2004 and 2015. For each pig, information extracted from the medical record included history; signalment; clinical signs; physical examination, diagnostic imaging, and diagnostic test results; perioperative management; surgical diagnosis, duration, and procedures performed; postoperative complications; and outcome. Descriptive data were generated. RESULTS 11 pet pigs underwent 12 celiotomies during the study period. Five pigs with intestinal obstructions caused by foreign bodies survived to hospital discharge. Four pigs were euthanized during surgery: 2 because of extensive adhesions that prevented correction of an intestinal obstruction, 1 because of a perforated spiral colon, and 1 because of neoplasia. One pig with a fecal impaction in the spiral colon died during anesthetic recovery. A diagnosis was not achieved for 1 pig, which was euthanized after surgery because of a deteriorating clinical condition. For the pig that underwent 2 celiotomies, the first procedure was an enterotomy for removal of a foreign body, and the second was an intestinal bypass of a stricture caused by adhesions at the previous enterotomy site. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated prognosis was good for pet pigs following surgical removal of gastrointestinal foreign bodies; however, the presence or development of intra-abdominal adhesions appeared to adversely affect prognosis.

A carboxymethylcellulose-heparin combination for the prevention of surgical adhesions

BACKGROUND

Adhesions are a major clinical problem after abdominal surgery. Despite decades of research, therapies to prevent adhesion formation are suboptimal.

MATERIALS AND METHODS

We have investigated combinations of carboxymethylcellulose (CMC) and heparin at preventing surgical adhesions in two rat models of adhesion formation. The first was the well-established cecal abrasion model, and the second was a model developed in our laboratory, the avascular mesenteric knot model. This model consistently produced adhesions at the knot in 90% of experiments and causes little or no tissue injury.

RESULTS

Topical administration of CMC 4% gave optimal results in the avascular knot model, but was less effective in the cecal abrasion model. This concentration of CMC was combined with a range of heparin doses between 0.5 and 160 IU/mL in the cecal abrasion model. These heparin doses, apart from the lowest (0.5 IU/mL), were effective in preventing adhesion formation in combination with CMC, as was the commercially available topical product Lipactin. The optimal dose was 30 IU/mL, that abolished adhesions, but there was little difference at doses between 2 and 160 IU. Heparin was effective in doses as low as 2 IU/mL when in combination with CMC. Heparin 160 IU/mL, but not heparin 30 IU/mL or Lipactin, significantly increased the degree of bleeding post cecal abrasion surgery.

CONCLUSIONS

Topical application of tiny doses of heparin, in combination with CMC 4% gel, significantly reduces adhesion formation in experimental models. We suggest that this cheap and, as far as we know, safe intervention should be evaluated in human clinical trials.

Efficacy of anti-adhesion gel of carboxymethylcellulose with polyethylene oxide on peripheral nerve: Experimental results on a mouse model

INTRODUCTION

Perineural scar formation is responsible for pain and loss of function after surgical procedures. Neurolysis and application of anti-adhesion gels are required to restore a gliding surface. We tested a carboxymethylcellulose (CMC) and polyethylene oxide (PEO) gel on mouse sciatic nerve to describe its safety and efficacy.

METHODS

Adult mice underwent a surgical procedure in which we burned the muscular bed of the sciatic nerve bilaterally (Burned group) and applied anti-adhesion gel to 1 of the nerves (Burned+gel group). After 3 weeks, we studied scar tissue by biomechanical and histological evaluation.

RESULTS

Both histological and biomechanical analysis showed that the gel reduced perineural scarring. The difference between the Burned and Burned+gel groups was statistically significant.

CONCLUSIONS

CMC-PEO gel can reduce perineural scar tissue. In histological section, scar tissue was present in both groups, but in the Burned+gel group a gliding surface was identified between scar and nerve.

Peritoneal response to abdominal surgery: the role of equine abdominal adhesions and current prophylactic strategies

Intra-abdominal adhesions constitute a significant clinical and surgical problem that can lead to complications such as pain and bowel occlusion or subocclusion. These adhesions are frustrating and potentially fatal, representing a major postoperative complication in abdominal surgery. It is estimated that 32% of horses undergoing laparotomy will present clinical symptoms due to adhesions, but the true prevalence is not known because a large proportion of animals with postoperative recurrent colics are medically treated or submitted to euthanasia without necropsy. Adhesions are highly cellular, vascularized, dynamic structures that are influenced by complex signaling mechanisms. Understanding their pathogenesis could assist in applying better therapeutic strategies and in developing more effective antiadhesion products. Currently, there are no definitive strategies that prevent adhesion formation, and it is difficult to interpret the results of existing studies due to nonstandardization of an induction model and evaluation of their severity. The best clinical results have been obtained from using minimally traumatic surgical techniques, anti-inflammatory agents, antimicrobials, anticoagulants, and mechanical separation of serosal surfaces by viscous intraperitoneal solutions or physical barriers. This paper aims to review adhesion formation pathogenesis, guide the understanding of major products and drugs used to inhibit adhesion formation, and address their effectiveness in the equine species.

Right dorsal displacement of the large colon as a cause of surgical colic in three foals in New Zealand

CASE HISTORY

Over a 3-year period between July 2008 and July 2011, 10 exploratory laparotomies were performed on foals in a Waikato referral facility in New Zealand.

CLINICAL FINDINGS

Right dorsal displacement of the large colon (RDDLC) was identified during four exploratory laparotomies in three foals that presented for mild-to-moderate colic that was non-responsive to medical management. One foal required a repeat laparotomy 7 weeks post initial surgery, and RDDLC was again diagnosed.

DIAGNOSIS

Right dorsal displacement of the large colon in foals.

CLINICAL RELEVANCE

Further investigation may identify risk factors or management practices contributing to this condition. This is an important and uncommonly reported cause of surgical colic in foals, that is also important to consider in non-responsive medical colic cases that do not appear to be associated with severe pain, but may still require prompt surgical intervention to avoid a strangulating obstruction. The incidence of the condition in one Waikato referral facility appears higher than what could be expected based on the current literature.

Prevention of ischaemia-induced small intestinal adhesions in foals

REASONS FOR PERFORMING STUDY

Treatments addressing variously theorised pathophysiological mechanisms of small intestinal adhesions have been reported. This study applied those classes of treatments to the most clinically relevant aetiology of post operative adhesions.

HYPOTHESIS

Treatments addressing the pathophysiology of ischaemia-reperfusion induced adhesions would accordingly reduce the incidence of adhesions from this model.

METHODS

Four classes of treatments were administered for 72 h to 16 foals subjected to complete ischaemia followed by reperfusion to create peritoneal adhesions. These groups were: 1) FPG group--flunixin meglumine (1.1 mg/kg bwt i.v., divided q.i.d.), potassium penicillin G (22,000 iu/kg bwt i.v., q.i.d.) and gentamicin (2.2 mg/kg bwt i.v., t.i.d.); 2) HEP group--heparin (80 iu/kg bwt subcut., b.i.d.); 3) DMSO group--dimethylsulphoxide (DMSO) (20 mg/kg bwt [diluted in 500 ml normal saline] i.v., b.i.d.); and 4) SCMC group--sodium carboxymethylcellulose (500 ml 3% sterile solution intraperitoneally, administered only at the beginning of surgery).

RESULTS

Post operative intestinal obstruction did not occur in any foal. After 10 days, necropsy revealed bowel-to-bowel adhesions in none of the FPG or DMSO groups, in 2/4 of the SCMC group, in 3/4 of the HEP group and 5/6 foals subjected to the procedure without treatment (UIR group).

CONCLUSIONS

Inhibition of the inflammation associated with ischaemia and reperfusion in foals treated with FPG or DMSO decreased small intestinal adhesions in foals.

POTENTIAL RELEVANCE

Although anti-inflammatory therapy was shown to eliminate bowel-bowel adhesions in this controlled study, it must be remembered that clinical cases are without control. These therapies are advised to improve the result but are unlikely to eliminate the problem.

Update on recent advances in equine abdominal surgery

In recent years important advancements in colic surgery have led to improved prediction of survival rates, better survival rates, and decreased complication rates. This article describes several modalities to combat and prevent incisional hernia and intestinal adhesion formation in horses undergoing colic surgery. These modalities have had a positive impact on reducing complications in horses after surgery.

Intra-abdominal adhesions in horses: A retrospective evaluation of repeat laparotomy in 99 horses with acute gastrointestinal disease

The objectives of this study were (1) to determine the prevalence of pathological abdominal adhesion formation following exploratory laparotomy; (2) to establish the site of adhesion formation and its relationship to the initial lesion; (3) to ascertain whether the development of intra-abdominal adhesions decreases long-term survival and (4) to identify risk factors for adhesion formation. Of 1014 horses treated surgically for acute gastrointestinal disease, 113 (10.1%) were subjected to repeat laparotomy, with surgical records available for 99 of these cases. Pathological adhesions were the most common diagnosis at repeat laparotomy (28%), followed by complications associated with the anastomosis (16%). Adhesions were not associated with the site of the primary lesion, resection, or endotoxaemia, consistent with the hypothesis that surgical trauma is the most important stimulus in adhesion formation. Together these findings strongly support the need for pan-abdominal, rather than site-specific adhesion prevention measures in all horses undergoing exploratory laparotomy.

In vivo performance of antibiotic embedded electrospun PCL membranes for prevention of abdominal adhesions

The aim of this study was to prepare nonwoven materials from poly(epsilon-caprolactone) (PCL) and their antibiotic containing forms by electrospinning, so as to prevent postsurgery induced abdominal adhesions in rats. epsilon-Caprolactone was first polymerized by ring-opening polymerization, and then it was processed into matrices composed of nanofibers by electrospinning. A model antibiotic (Biteral) was embedded within a group of PCL membranes. In the rat model, defects on the abdominal walls in the peritoneum were made to induce adhesion. The plain or antibiotic embedded PCL membranes were implanted on the right side of the abdominal wall. No membrane implantation was made on the left side of the abdominal wall that served as control. Macroscopical and histological evaluations showed that using these barriers reduces the extent, type, and tenacity of adhesion. The antibiotic embedded membranes significantly eliminated postsurgery abdominal adhesions, and also improved healing.

Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 3: Long-term complications and survival

REASONS FOR PERFORMING STUDY

Few studies have evaluated long-term survival and complication rates in horses following surgical treatment of colic, making it difficult to offer realistic advice concerning long-term prognosis.

OBJECTIVE

To review the complications occurring after discharge from hospital and survival to >12 months after surgery of 300 horses undergoing exploratory laparotomy for acute colic. Pre-, intra- and post operative factors that affected long-term complications and long-term survival were assessed.

METHODS

History, clinical findings, surgical findings and procedures and post operative treatments of 300 consecutive surgical colic cases (1994-2001) were reviewed. Long-term follow-up information was retrieved from case records and telephone enquiries from owners.

RESULTS

The long-term (>12 months) survival rate for 204 horses discharged after colic surgery and for which follow-up information was available was 84%. The most common complication after discharge was colic, affecting 35.1% of horses following a single laparotomy. Colic was most common in horses that had had small intestinal obstructions, bowel resection or post operative ileus. Abdominal adhesions were most common in horses that presented with severe colic due to strangulation of small intestine. Ventral hernia formation occurred in 8% of horses, and was most common in horses that had had post operative wound drainage or infection.

CONCLUSIONS

This study identified various factors that appear to predispose horses to long-term complications after colic surgery.

POTENTIAL RELEVANCE

Further evaluation of strategies that might reduce the incidence of such complications are needed; in particular, the value of intraperitoneal heparin should be evaluated, and procedures designed to reduce the rates of wound drainage and infection assessed.

Recent advances in equine abdominal surgery

Laparoscopy is a minimally invasive procedure that has applications as a diagnostic, therapeutic and prognostic technique. Specialized equipment is necessary to perform equine laparoscopy, and there is a large range of instruments, both disposable and non-disposable available. Laparoscopic procedures described include ovariectomy, cryptorchidectomy, adhesiolysis and herniorrhaphy. Laparoscopy can be performed in a standing or dorsally recumbent position, depending on surgeon preference, patient status and the procedure to be performed. Stapling equipment is frequently used in gastrointestinal surgery in horses. Advantages include decreased surgical time and a decrease in the risk of contamination. Stapling equipment is often used in creating anastomoses, both in the large and small intestines, as well as in vessel ligation. New surgical techniques intended to decrease adhesion formation include the use of carboxymethylcellulose and bioresorbable patches. Indwelling abdominal drains can be used for peritoneal lavage following surgery and also appear to decrease the risk of adhesion formation. Improvements in post-operative care, including the treatment of post-operative ileus and endotoxaemia can significantly improve the outcome of horses that have undergone surgery for abdominal disorders. Recommendations for the use of prokinetic agents in horses with ileus vary widely. Prokinetic agents include local anaesthetics, macrolide antimicrobials, cholinergic agonists and dopamine antagonists. Endotoxaemia is common in horses following surgery for gastrointestinal disorders. The antibiotic polymyxin B binds to the circulating endotoxin molecule, decreasing its half-life in the intra-vascular space and reducing associated inflammation. This drug appears to be an effective and affordable treatment option for horses with endotoxaemia. The use of specific cyclooxygenase inhibitors in veterinary medicine have been studied recently. Selective cyclooxygenase-2 inhibitors may provide comparable anti-inflammatory and analgesic properties to the non-selective non-steroidal anti-inflammatory drugs. These drugs appear to have similar clinical effectiveness and will hopefully minimize deleterious side effects. The optimal healing of ventral midline incisions in horses is related to many factors including appropriate suture patterns and bite size, in addition to appropriate post-operative exercise recommendations. Recent advances in surgical techniques and post-operative care should decrease the morbidity and mortality associated with abdominal surgery. This article provides an overview of some of these advances.

Surgical abdomen of the calf

Although underrepresented compared with infectious diseases, calves' surgical abdomen diseases and abdominal surgery are a part of daily veterinary practice. Clinical presentations may differ from adult cattle and change rapidly. The decision whether to perform abdominal surgery or refer the animal has to take into consideration the condition and its prognosis for the calf. This article discusses clinical presentation of calves and focuses on specific situations with a detailed description of the surgical techniques, atresia coli, and umbilical remnants infection.

Evaluation of a Sheep Laparoscopic Uterine Trauma Model and Repeat Laparoscopy for Evaluation of Adhesion Formation and Prevention with Sodium Carboxymethylcellulose

OBJECTIVE

To evaluate topical application of 1% sodium carboxymethyl cellulose (SCMC) for prevention of postoperative adhesions in a laparoscopic model of uterine trauma in sheep.

STUDY DESIGN

Experimental study.

ANIMALS

Fourteen non-pregnant ewes.

METHODS

Ewes were randomly assigned to 1 of 2 groups: control (saline solution) or 1% SCMC treatment. By left flank laparoscopy, traumatic forceps were used to create serosal trauma (1.5 x 5 cm) and hemorrhage on the left uterine horn. Either 30 mL saline solution or 30 mL 1% SCMC was applied topically to the traumatized uterine horn. Adhesion formation was evaluated by repeat laparoscopy at days 14 and 21. Sheep were euthanatized on day 28 for necropsy evaluation of adhesions.

RESULTS

Five control sheep had adhesions of the uterine horn by day 14, but only 4 had adhesions at day 21, and 2 at day 28. Adhesions did not occur in SCMC-treated sheep. No adhesions occurred elsewhere in the abdomen.

CONCLUSIONS

Laparoscopically created uterine trauma is an effective method for induction of uterine adhesions, and laparoscopy is an excellent method for serial evaluation of adhesion formation. SCMC (1%) was effective at preventing adhesion formation in sheep and no inflammatory response was noted.

CLINICAL RELEVANCE

SCMC (1%) should be considered for prevention of adhesions in abdominal surgery in sheep.

Comparison of two laparoscopic treatments for experimentally induced abdominal adhesions in pony foals

OBJECTIVE

To compare laparoscopic dissection with-laparoscopic dissection combined with abdominal instillation of ferric hyaluronate gel for the treatment of experimentally induced adhesions in pony foals.

ANIMALS

12 healthy pony foals.

PROCEDURE

A serosal abrasion method was used to create adhesions at 4 sites on the jejunum (day 0). At day 7 laparoscopy was performed and the adhesions observed in each foal were recorded. In group-1 foals (n = 6), the adhesions were separated laparoscopically (treatment 1). In group-2 foals (n = 6), 300 mL of 0.5% ferric hyaluronate gel was infused into the abdomen after the adhesions were separated laparoscopically (treatment 2). At day 24, terminal laparoscopy was performed and the adhesions observed were recorded. Total number of adhesions within each group was compared between day 7 and 24. Data were analyzed to determine whether an association existed between the number of adhesions on day 24 and treatment type.

RESULTS

At day 24, the number of adhesions was significantly decreased within each group, compared with the number of adhesions at day 7 (group-1 foals, 10 vs 22 adhesions; group-2 foals, 3 vs 20 adhesions). Treatment 1 was associated with a significantly higher number of adhesions at day 24, compared with treatment 2 (odds ratio, 4.54; 95% confidence interval, 1.03 to 23.02).

CONCLUSION AND CLINICAL RELEVANCE

Abdominal instillation of 0.5% ferric hyaluronate gel after laparoscopic dissection was a more effective technique than laparoscopic dissection alone to treat experimentally induced adhesions in pony foals. Laparoscopic adhesiolysis following abdominal surgery in foals is a safe and effective 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.

Prevention and treatment of gastrointestinal adhesions

As with many aspects of clinical medicine, there is yet to be a single or definitive cure for postoperative adhesion formation. Current methods of prevention target risk factors predisposing horses to adhesion formation. Systemic pharmacologic therapies, such as antimicrobials, nonsteroidal anti-inflammatory drugs, Salmonella antiserum, and hyperimmune plasma, help to reduce abdominal inflammation and minimize the effects of endotoxemia. Intra-abdominal or systemic heparin aids in enhancing peritoneal fibrinolysis. Prokinetic therapy promotes early postoperative return of intestinal motility, minimizing the propensity for adhesion formation between apposing adynamic segments of intestine. Mechanical separation of potentially adhesiogenic serosal and peritoneal surfaces is commonly achieved with use of abdominal lavage, protective coating solutions, and barrier membranes. Ongoing and future research is directed toward a better understanding of the local effects of intestinal trauma and the corresponding response of the fibrinolytic system. Recognition of horses at high risk for adhesion formation helps to guide the equine surgeon to an appropriate perioperative and intraoperative plan for adhesion prevention, including good surgical technique and a combination of adjunct therapies.

Carboxymethylcellulose coated on visceral face of polypropylene mesh prevents adhesion without impairing wound healing in incisional hernia model in rats

Adhesions between viscera and mesh may result in intestinal obstruction and fistulae formation. Fewer adhesions with sodium carboxymethylcellulose (SCMC)-coated polypropylene mesh (PM) has been reported, but impaired wound healing was the major concern. We investigated the adhesion-prevention effect of SCMC in different concentrations, as coating only on visceral face of PM and its effects on wound healing. A full-thickness abdominal wall defect was created in 28 rats, which were then divided into three groups. In Group I (control), the defect was repaired with PM only; in Group II and Group III, the defects were repaired with 1% and 1.6% SCMC-coated-PM, respectively. All animals were sacrificed at day 30, and histological evaluation and adhesion scoring were done. Animals in the group in which 1.6% SCMC-coated PM was used developed significantly fewer adhesions compared with other animals (P=0.04). Histological evaluation using a semiquantitative scoring system showed no difference between the groups in fibrosis and inflammation scores (P=0.9 and P=0.3, respectively), and thickness of fibrosis on mesh was also similar (P=0.5). SCMC in 1.6% concentration as coating only on the visceral face of PM reduced the incidence and severity of adhesions without impairing wound healing.

Use of a high-molecular-weight carboxymethylcellulose in a tissue protective solution for prevention of postoperative abdominal adhesions in ponies

OBJECTIVE

To evaluate efficacy and safety of IP administration of high-molecular-weight carboxymethylcellulose (HMW CMC) for the prevention of postoperative intra-abdominal adhesions in ponies.

ANIMALS

10 ponies.

PROCEDURE

A 1% solution of HMW CMC was instilled intra-abdominally prior to surgery in 5 ponies, whereas 5 control ponies did not receive HMW CMC. Postoperative adhesions were induced by use of a bowel-abrasion method comprising laparotomy, typhlotomy, and abrasion of jejunal serosa at multiple sites with placement of 3 sutures at each site. Day of surgery was day 0. After surgery, ponies were monitored, and hematologic, serum biochemical, and peritoneal fluid analyses were performed on days 1, 2, 3, 5, 7, and 10. On day 10, ponies were euthanatized. Intra-abdominal adhesions were recorded, and tissue samples were collected for histologic examination.

RESULTS

A significantly greater number of adhesions, number of multiple adhesions, and mean incidence of adhesions were identified in control ponies, compared with CMC-treated ponies. Mean peritoneal fluid WBC count on day 7 and serum fibrinogen concentrations on days 5 and 7 were significantly higher in control ponies, compared with CMC-treated ponies. Results of serum biochemical analyses did not differ significantly between the 2 groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Intra-abdominal use of 1% HMW CMC during surgery was effective for preventing postoperative adhesions in ponies. Use of HMW CMC did not have detrimental effects on wound healing, intra-abdominal defenses, or patient health. A 1% solution of HMW CMC may be used routinely during abdominal surgery of horses for prevention of postoperative adhesions.