Effect of surgical adhesion reduction devices on the propagation of experimental intra-abdominal infection

Local antimicrobial delivery from temperature-responsive hydrogels reduces incidence of intra-abdominal infection in rats

The objective of this study was to evaluate local antimicrobial delivery from temperature-responsive hydrogels for preventing infection in a rat model of intra-abdominal infection (IAI), and to determine whether delivery of tobramycin and vancomycin in combination is effective against IAI pathogens. Rats received intraperitoneal inoculation of E. coli, rat cecal contents, or cecal contents supplemented with E. coli, and received either no treatment, subcutaneous cefoxitin, or local delivery from hydrogels containing vancomycin, tobramycin, or both antimicrobials. Only the hydrogel with tobramycin and vancomycin significantly increased the infection free-rate compared to no treatment for all inocula (E. coli: 13/17, p < 0.0001; cecal contents: 11/17, p = 0.0013; cecal contents + E. coli: 15/19, p < 0.0001). Additionally, tobramycin and vancomycin displayed no synergy or antagonism against clinical isolates in vitro. Local delivery of tobramycin and vancomycin from temperature-responsive hydrogels provides broad coverage and high antimicrobial concentrations for several hours that may be effective for preventing IAIs.

Limited efficacy with additional adverse effect of anti-adhesion barrier at primary cesarean section

BACKGROUND/PURPOSE

In our experience, adhesion after the primary CS is generally minimal or nonexistent. However, adhesion barriers users have experienced more febrile episodes that may require therapeutic antibiotics during the postcesarean period. We evaluated clinical efficacy of HA-CMC and ORC to prevent adhesion at secondary CS and the post-operative outcome at primary and secondary CS.

METHODS

This retrospective study includes 199 Asian women undergoing primary and secondary cesarean section between January1, 2011, and September 31, 2019. We used linear and logistic regression to analyze risk factors of postcesarean fever. An interaction term analysis was performed to examine the effect of surgical site infection risk factors and use of adhesion barrier on postcesarean fever rates.

RESULTS

We found that use of adhesion barrier at the primary cesarean section is associated with a significantly higher incidence of postcesarean fever (p = 0.045), which is an independent risk factor of postcesarean fever (adjusted hazard ratio (Adj-HR)= 3.53, 95% CI = 1.03-10.24, p = 0.045). The strongest risk factor for postcesarean fever is the use of anti-adhesion film during emergency cesarean section (p = 0.041). In the subgroup of labor before operation and emergency cesarean section, adhesion barrier user had significant higher risk of postcesarean fever than nonuser (p = 0.018, Adj-HR = 12.12, 95% CI = 1.53-95.78; emergency cesarean section: p = 0.016, Adj-HR = 12.71, 95% CI = 1.62-99.62).

CONCLUSION

Use of anti-adhesion films during emergency cases and with a significantly higher risk of postcesarean fever which potentially means increased risk of surgical site infection. Therefore, we do not suggest routine application of anti-adhesion films during cesarean deliveries especially in emergency cesarean section or in a woman having labor before operation.

Polylactic acid nanosheets in prevention of postoperative intestinal adhesion and their effects on bacterial propagation in an experimental model

Background

Ultrathin films (nanosheets) adhere tightly to organ surfaces but prevent adhesion to other organs. The antiadhesive effect of nanosheets and their effect on bacterial propagation were investigated in a murine intestinal adhesion model.

Methods

Polylactic acid nanosheets (approximately 80 nm thick) were produced. Serosal defects were created by peeling off the intestinal serosa; these were left open or covered with nanosheets or Seprafilm® and the formation of intestinal adhesions was analysed. To examine bacterial propagation, a nanosheet or Seprafilm® was placed on intact murine jejunum followed by Escherichia coli inoculation at the site.

Results

Treatment both with nanosheets and with Seprafilm® reduced postoperative intestinal adhesion (mean adhesion score 0·67 for nanosheets, 0·43 for Seprafilm® and 2·87 for no antiadhesive treatment; P &lt; 0·001 for nanosheets or Seprafilm® versus no adhesive treatment). Nanosheet treatment did not affect bacterial propagation in the peritoneal cavity, whereas Seprafilm®-treated mice showed bacterial propagation, leading to increased mortality.

Conclusion

Nanosheets may be effective novel antiadhesive agents even in the presence of bacterial contamination. Surgical relevanceIntra-abdominal adhesions following surgical contamination can trigger postoperative complications and lead to deterioration in long-term quality of life. However, currently there are no effective antiadhesion materials to prevent the formation of adhesions.Treatment with ultrathin nanosheets effectively reduced postoperative intestinal adhesion in an experimental mouse model, and did not affect bacterial propagation in the peritoneal cavity.These nanosheets are potent novel antiadhesive materials that potentially can be applied even in contaminated conditions.

A multicentre, randomised, controlled trial to assess the safety, ease of use, and reliability of hyaluronic acid/carboxymethylcellulose powder adhesion barrier versus no barrier in colorectal laparoscopic surgery

Background

Intra-peritoneal adhesions are frequent following abdominal surgery and are the most common cause of small bowel obstructions. A hyaluronic acid/carboxymethylcellulose (HA/CMC) film adhesion barrier has been shown to reduce adhesion formation in abdominal surgery. An HA/CMC powder formulation was developed for application during laparoscopic procedures.

Methods

This was an exploratory, prospective, randomised, single-blind, parallel-group, Phase IIIb, multicentre study conducted at 15 hospitals in France to assess the safety of HA/CMC powder versus no adhesion barrier following laparoscopic colorectal surgery. Subjects ≥18 years of age who were scheduled for colorectal laparoscopy (Mangram contamination class I‒III) within 8 weeks of selection were eligible, regardless of aetiology. Participants were randomised 1:1 to the HA/CMC powder or no adhesion barrier group using a centralised randomisation list. Patients assigned to HA/CMC powder received a single application of 1 to 10 g on adhesion-prone areas. In the no adhesion barrier group, no adhesion barrier or placebo was applied. The primary safety assessments were the incidence of adverse events, serious adverse events, and surgical site infections (SSIs) for 30 days following surgery. Between-group comparisons were made using Fisher’s exact test.

Results

Of those randomised to the HA/CMC powder (n = 105) or no adhesion barrier (n = 104) groups, one patient in each group discontinued prior to the study end (one death in each group). Adverse events were more frequent in the HA/CMC powder group versus the no adhesion barrier group (63% vs. 39%; P <0.001), as were serious adverse events (28% vs. 11%; P <0.001). There were no statistically significant differences between the HA/CMC powder group and the no adhesion barrier group in SSIs (21% vs. 14%; P = 0.216) and serious SSIs (12% vs. 9%; P = 0.38), or in the most frequent serious SSIs of pelvic abscess (5% and 2%; significance not tested), anastomotic fistula (3% and 4%), and peritonitis (2% and 3%).

Conclusions

This exploratory study found significantly higher rates of adverse events and serious adverse events in the HA/CMC powder group compared with the no adhesion barrier group in laparoscopic colorectal resection.

Trial registration

ClinicalTrials.gov NCT00813397. Registered 19 December 2008.

Benefits and harms of adhesion barriers for abdominal surgery: a systematic review and meta-analysis

BACKGROUND

Formation of adhesions after peritoneal surgery results in high morbidity. Barriers to prevent adhesion are seldom applied, despite their ability to reduce the severity of adhesion formation. We evaluated the benefits and harms of four adhesion barriers that have been approved for clinical use.

METHODS

In this systematic review and meta-analysis, we searched PubMed, CENTRAL, and Embase for randomised clinical trials assessing use of oxidised regenerated cellulose, hyaluronate carboxymethylcellulose, icodextrin, or polyethylene glycol in abdominal surgery. Two researchers independently identified reports and extracted data. We compared use of a barrier with no barrier for nine predefined outcomes, graded for clinical relevance. The primary outcome was reoperation for adhesive small bowel obstruction. We assessed systematic error, random error, and design error with the error matrix approach. This study is registered with PROSPERO, number CRD42012003321.

FINDINGS

Our search returned 1840 results, from which 28 trials (5191 patients) were included in our meta-analysis. The risks of systematic and random errors were low. No trials reported data for the effect of oxidised regenerated cellulose or polyethylene glycol on reoperations for adhesive small bowel obstruction. Oxidised regenerated cellulose reduced the incidence of adhesions (relative risk [RR] 0·51, 95% CI 0·31-0·86). Some evidence suggests that hyaluronate carboxymethylcellulose reduces the incidence of reoperations for adhesive small bowel obstruction (RR 0·49, 95% CI 0·28-0·88). For icodextrin, reoperation for adhesive small bowel obstruction did not differ significantly between groups (RR 0·33, 95% CI 0·03-3·11). No barriers were associated with an increase in serious adverse events.

INTERPRETATION

Oxidised regenerated cellulose and hyaluronate carboxymethylcellulose can safely reduce clinically relevant consequences of adhesions.

FUNDING

None.

Utilization and safety of sodium hyaluronate-carboxymethylcellulose adhesion barrier

BACKGROUND

Little is known about the use and toxicity of antiadhesion substances such as sodium hyaluronate-carboxymethylcellulose.

OBJECTIVE

We analyzed the patterns of use and safety of sodium hyaluronate-carboxymethylcellulose in patients undergoing colectomy and gynecologic surgery.

DESIGN

This is a retrospective cohort study.

SETTING

This study covered hospitals nationwide.

PATIENTS

All patients in the Premier Perspective database who underwent colectomy or hysterectomy from 2000 to 2010 were included in the analyses.

MAIN OUTCOME MEASURE

Hyaluronate-carboxymethylcellulose use was determined by billing codes. For the primary outcome, we used hierarchical mixed-effects logistic regression models to determine the factors associated with the use of hyaluronate-carboxymethylcellulose, whereas a propensity score-matched analysis was used to secondarily assess the association between hyaluronate-carboxymethylcellulose use and toxicity (abscess, bowel and wound complications, peritonitis).

RESULTS

We identified 382,355 patients who underwent hysterectomy and 267,368 who underwent colectomy. For hysterectomy, hyaluronate-carboxymethylcellulose use was 5.0% overall, increasing from 1.1% in 2000 to 9.8% in 2010. Hyaluronate-carboxymethylcellulose was used in 8.1% of those who underwent colectomy and increased from 6.2% in 2000 to 12.4% in 2010. The year of diagnosis and procedure volume of the attending surgeon were the strongest predictors of hyaluronate-carboxymethylcellulose use. After matching and risk adjustment, hyaluronate-carboxymethylcellulose use was not associated with abscess formation (1.5% vs 1.5%) (relative risk = 0.97; 95% CI, 0.84-1.12) in those who underwent hysterectomy. A patient receiving hyaluronate-carboxymethylcellulose had a 13% increased risk of abscess (17.4% vs 15.0%) (relative risk = 1.13; 95% CI, 1.08-1.17) after colectomy.

LIMITATIONS

This was an observational study.

CONCLUSION

Hyaluronate-carboxymethylcellulose use has increased over the past decade for colectomy and hysterectomy. Although there is no association between hyaluronate-carboxymethylcellulose use and abscess following hysterectomy, hyaluronate-carboxymethylcellulose use was associated with a small increased risk of abscess after colectomy.

Seprafilm® adhesion barrier: (1) a review of preclinical, animal, and human investigational studies

The aim of this study was to provide a single site resource for investigators, clinicians, and others seeking preclinical, animal, and human investigational studies concerning the postsurgical, anti-adhesion barrier Seprafilm™ (Genzyme Corporation, Cambridge, MA). All published preclinical, animal, human extra-abdominal research as of July 2011 have been summarized and included in this document. Searches of Medline and EMBASE Drugs and Pharmaceuticals databases were conducted for original preclinical, animal, and human extra-abdominal studies involving Seprafilm. Preclinical, animal, and extra-abdominal human investigational studies are the study selection for this manuscript. Intraabdominal use is discussed in the accompanying manuscript. Data extraction includes systematic manuscript review. Summary of preclinical, animal, and extra-abdominal human investigational use of Seprafilm by surgical discipline were gathered for data synthesis. The clinical use of Seprafilm, which was approved by the FDA for intra-abdominal procedures, is supported by preclinical and animal studies relating to general surgical and obstetrical/gynecological applications. Findings from preclinical, animal, and human investigational studies at other sites throughout the body raises the potential for additional human clinical trials to assess efficacy and safety following surgical procedures at non-abdominal locations.

Improvement of flexor tendon reconstruction with carbodiimide-derivatized hyaluronic acid and gelatin-modified intrasynovial allografts: study of a primary repair failure model

BACKGROUND

Tendon grafts play an important role in flexor tendon reconstruction. This study was an investigation of the effects of surface modification of allograft intrasynovial tendons with carbodiimide-derivatized hyaluronic acid and gelatin in an in vivo canine model. To mimic the actual clinical situation, a novel and clinically relevant model of a failed primary flexor tendon repair was used to evaluate the flexor tendon grafts.

METHODS

Twenty-eight flexor digitorum profundus tendons from the second and fifth digits of fourteen dogs were lacerated and repaired in zone II in a first-surgery phase. The dogs were allowed free active motion postoperatively. In a second phase, six weeks later, the tendons were reconstructed with use of a flexor digitorum profundus allograft. In each dog, one graft was treated with carbodiimide-derivatized hyaluronic acid and gelatin (the CHG group) and the other was treated with saline solution, as a control. The dogs were restricted from free active motion, but daily therapy was performed beginning on postoperative day 5 and continued until six weeks after the operation, when the animals were killed. The outcomes were evaluated on the basis of digit work of flexion, gliding resistance, healing at the distal attachment, graft cell viability, histological findings, and findings on scanning electron microscopy.

RESULTS

In the first phase, all twenty-eight repaired tendons ruptured, with scar and adhesion formation in the repair site. Six weeks after allograft reconstruction, the mean work of flexion was 0.37 and 0.94 N-mm/degree in the CHG group and the saline-solution control group, respectively; these values were significantly different (p < 0.05). The gliding resistance in the CHG group was also significantly less than that in the saline-solution control group (0.18 versus 0.28 N) (p < 0.05), but no difference between groups was observed with regard to the distal tendon-bone pullout strength. Histological analysis showed that tenocytes in the host tendon proliferated and migrated toward the acellular allograft.

CONCLUSIONS

This primary repair failure model was reproducible and reliable, with a uniform failure pattern, and provides an appropriate and clinically relevant animal model with which to study flexor tendon reconstruction. The surface modification of allografts with carbodiimide-derivatized hyaluronic acid and gelatin improved digital function and tendon gliding ability.

Two-component polyethylene glycol surgical sealant influence on intraperitoneal infection in a refined rodent model

OBJECTIVE

This study determined the influence of a 2-component polyethylene glycol surgical sealant (Coseal) as an adhesion prevention device on sepsis-related mortality and/or systemic bacterial translocation to the spleen.

STUDY DESIGN

A bacterial inoculum and telemetry probe were implanted in 50 treated and 49 untreated rats. Telemetry probes monitored core-body temperature to determine time of death. Spleens were collected on day 3 for quantitative bacteriology of Escherichia coli and Bacteroides fragilis.

RESULTS

Median survival time and mortality of treated rats (37.0 hours, 54.0%) were noninferior to untreated rats (47.5 hours, 55.1%). Median E coli titers in treated rats (2.24 log colony forming units/spleen) were significantly less than untreated rats (4.32 log colony forming units/spleen). B fragilis titers were not different.

CONCLUSION

This study demonstrates intraperitoneal administration of a 2-component polyethylene glycol surgical sealant as an adhesion prevention device does not alter time to death or sepsis-related mortality and/or systemic bacterial translocation to the spleen.

Carbodiimide-derivatized hyaluronic acid surface modification of lyophilized flexor tendon: a biomechanical study in a canine in vitro model

BACKGROUND

Intrasynovial grafts are the ideal solution to replace defects in intrasynovial flexor tendons, but autologous graft sources are rarely available. The purpose of the present study was to test the hypotheses that an intrasynovial tendon prepared with repetitive freeze-thaw cycles and lyophilization (as a means of reducing immunogenicity) has increased frictional force (gliding resistance) in comparison with fresh intrasynovial tendons and that a lyophilized intrasynovial flexor tendon that is modified with carbodiimide-derivatized hyaluronic acid and gelatin has decreased frictional force in comparison with untreated lyophilized tendons.

METHODS

Thirty-six flexor digitorum profundus tendons from the second and fifth digits of canine hind paws were randomly assigned to three groups. Twelve tendons were immediately assessed both mechanically and morphologically and served as the normal tendon group. The other twenty-four tendons were prepared with repetitive freeze-thaw cycles and lyophilization and were randomly assigned to two groups, including one group in which the tendons were treated with carbodiimide-derivatized hyaluronic acid and gelatin and one group in which the tendons were not treated. The frictional force was measured during 1000 cycles of simulated flexion-extension motion in all tendons, and the mean frictional forces were compared. The tendons were then observed with use of transmitted light microscopy for residual hyaluronic acid on the tendon surface, and the smoothness of the surface was evaluated with use of scanning electron microscopy.

RESULTS

The frictional force after lyophilization was significantly increased by 104.9% after the first cycle and by 99.5% after 1000 cycles in comparison with the normal tendon (p < 0.05). The frictional force of the lyophilized tendons after treatment with carbodiimide-derivatized hyaluronic acid and gelatin was not significantly different from that of normal tendons. The untreated lyophilized tendon surfaces were observed on scanning electron microscopy to be rough in appearance, whereas the normal surface and the surface treated with carbodiimide-derivatized hyaluronic acid and gelatin were smooth, with residual hyaluronic acid present on the gliding surface.

CONCLUSIONS

Lyophilization alters tendon surface morphology and increases tendon frictional force. Surface modification with carbodiimide-derivatized hyaluronic acid and gelatin can mitigate this adverse effect.

CLINICAL RELEVANCE

Tendon surface modification with carbodiimide-derivatized hyaluronic acid and gelatin can improve the gliding ability of lyophilized flexor tendons and therefore may improve the utility of lyophilized tendon allografts as a tendon graft substitute.

Feasibility and morbidity of using saline filled tissue expanders to reduce radiation-induced bowel injury in patients with gynecologic malignancies

OBJECTIVES

To evaluate the feasibility and morbidity of using saline filled tissue expanders (TE) to displace the small bowel during radiation therapy in patients with gynecologic malignancies.

STUDY DESIGN

Ten patients undergoing surgical exploration for a gynecologic malignancy and deemed to be at high risk for the late effects of radiation therapy were consented for the possible placement of a TE. Indication for placement was need for post-operative radiation. Small bowel exclusion was reported in terms of the lowest loop identified on treatment planning film using orally ingested barium.

RESULTS

Small bowel loops were excluded from the pelvis to varying degrees in all patients. Lowest identifiable bowel was marked at the L4-L5 interspace in one patient, L5-S1 interspace in three patients, at or near the sacral promontory in three patients, and to the middle of S2 in one patient. In two patients the TE was removed prior to simulation. Early complications included migration of the TE during treatment, development of a vesicovaginal fistula requiring immediate removal of the TE, and enterocutaneous fistula formation in a patient who developed an abscess following treatment completion. Another patient experienced a rectovaginal fistula 18 months after removal of the TE.

CONCLUSIONS

TE placement can successfully isolate small bowel from the pelvis. Usage should be individualized to minimize the likelihood of short and long-term complications, particularly in patients at higher risk of morbidity.

Enteric bacteria and their antigens may stimulate postoperative peritoneal adhesion formation

BACKGROUND

Intraabdominal sepsis causes exuberant inflammation, which results in dense adhesions. Translocation of enteric bacteria and/or their antigens after laparotomy may therefore also affect peritoneal healing by promoting local release of proinflammatory cytokines. Our hypothesis was that targeted counter therapy could be beneficial if such contamination was to augment postoperative adhesion formation.

METHODS

Two endotoxin-hyposensitive mouse strains (C3H/HeJ and C57BL/10ScCr) and their syngeneic counterparts (C3H/HeN and C57BL10/ScSn, respectively) underwent reproducible adhesion-inducing operation (AIO) (n=10/group) with sacrifice and blinded adhesion grading 14 days later. In addition, CD-1 mice were gavaged with fluorescein isothiocyanate labeled-lipopolysaccharide (FITC-LPS) prior to either AIO or sham laparotomy and had both peritoneal macrophages and circulating monocytes assessed by flow cytometry afterward. The cytokine-release response of resident peritoneal cells to LPS stimulation was assessed in vitro (murine peritoneal mast cell cultures) and in vivo (unoperated CD-1 mice administered LPS intraperitoneally [10 & 50 microg/mouse]). Finally, CD-1 mice (n=10/group) had AIO and received either bactericidal/permeability increasing protein (rBPI, 2 mg/mouse) or vehicle solution in the early postoperative period with assessment of adhesion formation 2 weeks later.

RESULTS

Both HeJ and ScCr mice had less adhesions than their controls (P=.0015 and .0001, respectively, Mann Whitney U test). FITC-LPS uptake by peritoneal macrophages was striking after AIO. Intraperitoneal LPS provoked significant local vascular endothelial growth factor (VEGF) release as did the process of AIO. In vitro, LPS induced significant interleukin-(IL)-6 release from isolated mast cells. Intraperitoneal administration of rBPI to CD-1 mice early after AIO markedly attenuated subsequent adhesion formation (P=.0003).

CONCLUSIONS

Peritoneal adhesion formation is exacerbated by peritoneal contamination due to translocation after laparotomy and may be attenuated by therapeutic antagonism.

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.

Auto-Cross-Linked Hyaluronic Acid Gel Does Not Reduce Intra-Abdominal Adhesions or Abscess Formation in a Rat Model of Peritonitis

BACKGROUND

Prevention of adhesion and abscess formation would decrease mortality and morbidity after peritonitis. In this study the effect of a new anti-adhesive, auto-cross-linked hyaluronic acid polysaccharide (ACP) gel, on adhesion and abscess formation was studied in a rat peritonitis model.

MATERIALS AND METHODS

In experiment 1, bacterial peritonitis was induced in 24 Wistar rats, using a cecal ligation and puncture model. Animals were randomized to receive 4 mL ACP gel (4%) or 4 mL phosphate buffered saline (PBS). After 2 weeks animals were killed and adhesions and abscesses were scored. In experiment 2, 72 rats underwent the same procedure but were randomized to receive 2 mL ACP gel, 4 mL ACP gel, or 4 mL PBS. After 1 and 3 weeks, respectively, half of the animals in each group were killed and adhesions and abscesses were scored.

RESULTS

The median total adhesion score was 12 (range, 3-20) in the ACP group and was 9 (range, 6-12) in the PBS group (not significant) in experiment 1. 91% of rats in the ACP group developed abscesses, versus 90% in the control group. There were no significant differences in abscess size or number of abscesses. In experiment 2, total adhesion scores in the 2 mL ACP group, 4 mL ACP group, and PBS group were 4 (range, 2-20), 6 (range, 1-11), and 6 (range, 1-18), respectively, (not significant) after 1 week and 3.5 (range, 1-8), 5 (range, 2-15), and 4 (range, 0-9), respectively, (not significant) after 3 weeks. All rats in the 2 mL ACP group and the PBS group and 83% of the 4 mL ACP group had developed abscesses after 1 week. After 3 weeks these percentages were 80, 75, and 73, respectively. There were no significant differences in size or number of abscesses between groups both after 1 and 3 weeks.

CONCLUSION

ACP does not reduce adhesion and abscess formation in a rat peritonitis model.

Surface treatment of flexor tendon autografts with carbodiimide-derivatized hyaluronic Acid. An in vivo canine model

BACKGROUND

Clinical and experimental studies have demonstrated that restrictive adhesions and poor digital motion are common complications after extrasynovial tendon grafting in an intrasynovial environment. The purpose of this study was to test the hypothesis that surface modification of an extrasynovial tendon with use of a carbodiimide-derivatized hyaluronic acid-gelatin polymer (cd-HA) improves gliding ability and digital function after tendon grafting in a canine model in vivo.

METHODS

The peroneus longus tendons from both hindpaws of twenty-four dogs were harvested and transplanted to replace the flexor digitorum profundus tendons in the second and fifth digits of one forepaw. Prior to grafting, one of the peroneus longus tendons was coated with cd-HA, which consists of 1% hyaluronic acid, 10% gelatin, 0.25% 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), and 0.25% N-hydroxysuccinimide (NHS), while the other was immersed in saline solution only. Eight dogs were killed at one, three, and six weeks. Digital normalized work of flexion, tendon gliding resistance, and hyaluronic acid quantification (with the hyaluronic acid-binding-protein staining technique) were the outcome measures.

RESULTS

The normalized work of flexion of the tendons treated with cd-HA was significantly lower than that of the saline-solution-treated controls at each time-point (p < 0.05). The gliding resistance of the cd-HA group was significantly lower than that of the saline-solution group at three and six weeks (p < 0.05). The ratio between the intensity of staining of the cd-HA-treated tendons with that of the saline-solution-treated controls was significantly greater at time-0 than at three or six weeks (p < 0.05), but there was no significant difference between time-0 and one-week values.

CONCLUSIONS

Treating the surface of an extrasynovial tendon autograft with a carbodiimide-derivatized hyaluronic acid-gelatin polymer decreases digital work of flexion and tendon gliding resistance in this flexor tendon graft model in vivo.

CLINICAL RELEVANCE

cd-HA gelatin may provide surgeons with a new and useful method to improve the quality of tendon graft surgery.

Optimization of surface modifications of extrasynovial tendon to improve its gliding ability in a canine model in vitro

Previous studies have shown that the carboxyl groups in hyaluronic acid (HA) could be activated by 1-ethy 1-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) to form intermediate O-acylisoureas, which can chemically bind to exposed amino groups on the tendon surface, leading to improved gliding ability. However, the optimal ratio and concentrations of the components in this chemical mixture were not investigated. The purpose of this study was to optimize the constituents of this tissue engineering approach to tendon surface modification, to reduce friction and improve durability. Peroneus longus (PL) tendons (n=40) were harvested from adult mongrel dogs along with the A2 pulley obtained from the ipsilateral hind paw. After the gliding resistance of the normal PL tendon was measured, the tendons were treated under varying concentrations of HA (0.5, 1, and 2%) and EDC/NHS (0.05, 0.25, and 1%) mixed with a 10% gelatin. Tendon friction was measured for 1000 cycles of simulated flexion/extension motion. Following testing, the residual HA on the tendon surface was evaluated by immunohistochemisty. The gliding resistance of the untreated PL tendons had a mean value of 0.087+/-0.021 N. After surface treatment, there was no significant difference in friction due to HA concentration alone, but the concentration of EDC/NHS and the interaction between HA concentration and EDC/NHS concentration had a significant effect on friction. Regardless of HA concentration, the friction after 1000 cycles was significantly decreased in preparations which included a 1% concentration of EDC/NHS. The tendons with lower gliding resistance presented a smoother surface on light microscopy and maintained more residual HA on the tendon surface. By varying the relative concentrations of HA, EDC, and NHS it is possible to optimize the effect of surface treatment on friction and durability in a canine extrasynovial tendon in vitro.

A randomized controlled trial of 0.5% ferric hyaluronate gel (Intergel) in the prevention of adhesions following abdominal surgery

INTRODUCTION

Intestinal adhesion following abdominal surgery is a significant sequela to abdominal surgery. Intergel is a hyaluronate-based gel that reduces the incidence of postoperative adhesions when added to the peritoneal cavity before closure in gynecologic surgery. This is a randomized controlled trial evaluating the efficacy and safety of Intergel in colorectal resections. Although the study aimed to recruit 200 patients based on power analysis, recruitment was suspended because of the high morbidity in the treatment group.

METHODS

A total of 32 patients were randomized to either Intergel treatment (treatment group) or no treatment (control group) following open abdominal surgery. Primary endpoints included the incidence of adhesive obstruction, the need for subsequent adhesiolysis, and the incidence of wound and anastomotic complications. A secondary endpoint involved quality-of-life assessment.

RESULTS

Seventeen patients were randomized to the treatment group and 15 to the control group. All patients, except 1 in the treatment group, underwent resection and anastomosis of the colon or rectum for benign or malignant disease. A significant difference was observed in the number of patients with postoperative morbidities between the 2 groups (65% treatment group versus 27% control group, P = 0.031). There was a high rate of anastomotic dehiscence (5 treatment group versus 1 control group, P = 0.178) and prolonged postoperative ileus (10 treatment group versus 2 control group, P = 0.011) observed in treatment group. One case of peritonitis occurred in the treatment group in the presence of an intact anastomosis. Wound complications were more common in treatment group but failed to reach statistical significance.

CONCLUSION

The use of Intergel in abdominal surgery where the gastrointestinal tract is opened leads to unacceptably high rates of postoperative complications.

Seprafilm Does Not Aggravate Intraperitoneal Septic Conditions or Evoke Systemic Inflammatory Response

PURPOSE

To determine whether Seprafilm aggravates the systemic inflammatory response and adversely affects the outcome of postoperative intraperitoneal septic conditions.

METHODS

We retrospectively analyzed the relationship between the intraperitoneal placement of Seprafilm and the rate of intraperitoneal septic complications in 278 consecutive patients. Experimentally, 40 rats were subjected to laparotomy with or without the intraperitoneal placement of Seprafilm. Bacterial peritonitis was induced by cecal ligation and puncture (CLP) and the serum cytokine levels were measured.

RESULTS

Seprafilm did not increase the rate of septic complications or aggravate inflammatory responses in patients with or without postoperative intraperitoneal inflammatory complications. Experimentally, there was no significant difference between the serum inflammatory cytokine levels after CLP with or without Seprafilm.

CONCLUSIONS

Seprafilm did not adversely affect postoperative inflammatory response or clinical outcomes, even in patients with intraperitoneal septic complications.

[Inhibition of abdominal abscess formation in rat: mortality by sepsis]

BACKGROUND

Intra-abdominal abscesses and adhesions play important roles on isolation of a septic process and on organism protection against bacteremia. On the other hand, such phenomenon difficults the afflux of immune factors and antibiotics to the septic site. The purpose of the present study was to evaluate the effect of abscess inhibition on survival of abdominal sepsis.

METHODS

Thirty adult Wistar rats were submitted to intraperitoneal injection of 50% rat feces solution. The animals were divided into three groups (n = 10). Group 1: control - feces solution; group 2: feces solution plus 0.9% saline solution; and group 3: feces solution plus 1% carboxymethylcellulose to inhibit abdominal adhesions. The three groups were divided into two subgroups (n = 5). Subgroup A: relaparorotomy after 4 days and investigation of the abdominal cavity; and subgroup B: follow-up during 30 days to evaluate the mortality and its cause. The Fisher test was utilized for statistical analyses.

RESULTS

The injection of 0.9% saline solution did not increase the mortality of the rats. However, the mortality enhanced in the group that received carboxymethylcellulose comparing with control group. That group developed less adhesions and abscesses.

CONCLUSION

This study demonstrated that the reduction of abscess formation and of intraperitoneal adhesions increases the mortality due to abdominal septic disease.

Prevention of postoperative abdominal adhesions by a novel, glycerol/sodium hyaluronate/carboxymethylcellulose-based bioresorbable membrane: a prospective, randomized, evaluator-blinded multicenter study

INTRODUCTION

Postoperative abdominal adhesions are associated with significant morbidity and mortality, placing a substantial burden on healthcare systems worldwide. Development of a bioresorbable membrane containing up to 23 percent glycerol and chemically modified sodium hyaluronate/carboxymethylcellulose offers ease of handling and has been shown to provide significant postoperative adhesion prevention in animals. This study was designed to assess the safety of glycerol hyaluronate/carboxymethylcellulose and to evaluate its efficacy in reducing the incidence, extent, and severity of postoperative adhesion development in surgical patients.

METHODS

Twelve centers enrolled 120 patients with ulcerative colitis or familial polyposis who were scheduled for a restorative proctocolectomy and ileal pouch-anal anastomosis with diverting loop ileostomy. Before surgical closure, patients were randomized to no anti-adhesion treatment (control) or treatment with glycerol hyaluronate/carboxymethylcellulose membrane under the midline incision. At ileostomy closure, laparoscopy was used to evaluate the incidence, extent, and severity of adhesion formation to the midline incision.

RESULTS

Data were analyzed using the intent-to-treat population. Treatment with glycerol hyaluronate/carboxymethylcellulose resulted in 19 of 58 patients (33 percent) with no adhesions compared with 6 of 60 adhesion-free patients (10 percent) in the no treatment control group (P = 0.002). The mean extent of postoperative adhesions to the midline incision was significantly lower among patients treated with glycerol hyaluronate/carboxymethylcellulose compared with patients in the control group (P < 0.001). The severity of postoperative adhesions to the midline incision was significantly less with glycerol hyaluronate/carboxymethylcellulose than with control (P < 0.001). Adverse events were similar between treatment and no treatment control groups with the exception of abscess and incisional wound complications were more frequently observed with glycerol hyaluronate/carboxymethylcellulose.

CONCLUSIONS

Glycerol hyaluronate/carboxymethylcellulose was shown to effectively reduce adhesions to the midline incision and adhesions between the omentum and small bowel after abdominal surgery. Safety profiles for the treatment and no treatment control groups were similar with the exception of more infection complications associated with glycerol hyaluronate/carboxymethylcellulose use. Animal models did not predict these complications.

Efficacy of three adhesion-preventing agents in reducing severe peritoneal trauma induced by bipolar coagulation in a laparoscopic rat model

OBJECTIVE

To compare the antiadhesion efficacy of three agents (4% icodextrin, ferric hyaluronate gel, and Ringer's lactate) in severe peritoneal trauma caused by bipolar coagulation in a laparoscopic rat model.

DESIGN

Prospective, randomized, blinded experimental study.

SETTING

International Laparoscopic Surgery Centre, Clermont-Ferrand, France.

ANIMAL(S)

Female Sprague-Dawley rats.

INTERVENTIONS

Animals were prospectively randomized to receive one of the three agents or to be controls. Coagulation of the parietal peritoneum was performed using a bipolar 40-W current followed by administration of an antiadhesion agent. Postoperative adhesion assessment was carried out on day 7 in 42 rats.

MAIN OUTCOME MEASURE(S)

Adhesions were scored according to their extent and severity.

RESULT(S)

Adhesions occurred in all rats, however, adhesion and vascular adhesion rate scores were significantly higher in controls compared with treated groups. Adhesions were more likely to be filmy and easily separable in the 4% icodextrin group compared with the Ringer's lactate solution group.

CONCLUSION(S)

Adhesion scores were decreased by the use of antiadherent agents. However, no rats were found to be free of adhesions after severe peritoneal trauma induced by 40-W bipolar coagulation of the peritoneum.

Current Management of Small-Bowel Obstruction

The most significant advances in the management of small-bowel obstruction are developments in imaging modalities available to assist in the diagnosis itself, as well as to possibly assist in the early identification of those cases requiring urgent operative decompression. The most marked of these have been in the use and interpretation of contrast-enhanced CT. This has decreased the use of barium studies and has largely supplanted ultrasound and magnetic resonance imaging in the management of these patients. Diagnostic and therapeutic laparoscopic techniques are also growing in both capability and popularity. Laparoscopic adhesiolysis and the adjuvant of bioresorbable membranes each hold promise but have yet to become established as standard treatment. Further progress is needed in the detection of early, reversible strangulation. As a consequence, the fundamentals of the surgical management of small-bowel obstruction have evolved little over the past 15 years. With our persistent inability to detect reversible ischemia, a substantial risk of progression to irreversible ischemia remains when surgery is delayed, particularly in the setting of suspected complete obstruction.

Prevention of postsurgery-induced abdominal adhesions by electrospun bioabsorbable nanofibrous poly(lactide-co-glycolide)-based membranes

OBJECTIVES

The objective of this study was to evaluate the efficacy of nonwoven bioabsorbable nanofibrous membranes of poly(lactideco-glycolide) for prevention of postsurgery-induced abdominal adhesions.

SUMMARY BACKGROUND DATA

Recent reports indicated that current materials used for adhesion prevention have only limited success. Studies on other bioabsorbable materials using a new fabrication technique demonstrated the promising potential of generating an improved and inexpensive product that is suitable for a variety of surgical applications.

METHODS

All rats underwent a midline celiotomy. The cecum was identified and scored using an abrasive pad until serosal bleeding was noted on the anterior surface. A 1 x 1 cm of abdominal wall muscle was excised directly over the cecal wound. The celiotomy was then closed in 2 layers immediately (control) after a barrier was laid in between the cecum and the abdominal wall. All rats underwent a second celiotomy after 28 days to evaluate the extent of abdominal adhesions qualitatively and quantitatively.

RESULTS

Cecal adhesions were reduced from 78% in the control group to 50% in the group using biodegradable poly(lactide-co-glycolide) (PLGA) nonwoven nanofibrous membranes (n = 10, P = 0.2) and to 22% in the group using membranes containing PLGA and poly(ethylene glycol)/poly(D,L-lactide) (PEG-PLA) blends (n = 9, P = 0.03). Electrospinning method also enabled us to load an antibiotic drug Cefoxitin sodium (Mefoxin; Merck Inc., West Point, PA) with high efficacy. The electrospun PLGA/PEG-PLA membranes impregnated with 5 wt% cefoxitin sodium, which amounts to approximately 10% of the systemic daily dose typically taken after surgery in humans, completely prevented cecal adhesions (0%) in rats.

CONCLUSIONS

Electrospun nonwoven bioabsorbable nanofibrous membranes of poly(lactide-co-glycolide) were effective to reduce adhesions at the site of injury using an objective rat model. The membrane acted as a physical barrier but with drug-delivery capability. The combined advantages of composition adjustment, drug-loading capability, and easy placement handling (relatively hydrophobic) make these membranes potentially successful candidates for further clinical evaluations.

Role of a hyaluronic-acid derivative in preventing surgical adhesions and abscesses related to dropped bile and gallstones in an experimental model

BACKGROUND

Despite its advantages, iatrogenic gallbladder perforation with resultant spillage of bile and gallstones is not uncommon during laparoscopic cholecystectomy. Although this is not generally considered a significant problem, spilled gallstones may cause problems even years after the operation. Hyaluronic acid has been introduced into clinical practice and successfully used to decrease postoperative adhesions after abdominopelvic surgery. In this study, we investigated the effectiveness of a hyaluronic-acid derivative in preventing complications related to spilled gallstones and bile leakage in an experimental study.

METHODS

In 60 Wistar-Albino rats, an upper-midline abdominal incision was made, and the rats were divided into 5 groups (n = 12 in each group) as follows: group I = laparotomy alone; group II = laparotomy and intraperitoneal instillation of sterile bile plus gallstones; group III = laparotomy and instillation of infected bile and gallstones; group IV = laparotomy and instillation of sterile bile and gallstones plus hyaluronic acid; and group V = laparotomy and instillation of infected bile and gallstones plus HA. A second-look laparotomy was performed on postoperative day 10 to assess intraperitoneal adhesions and abscesses. Intraperitoneal adhesions were scored, and breaking strengths of gallstones were measured.

RESULTS

Adhesion scores were significantly higher in groups II and III compared with groups I, IV, and V (P < 0.05). There was a statistically significant decrease in breaking strengths and adhesion scores in groups IV and V compared with groups II and III (P < 0.001).

CONCLUSIONS

Whether infected or not, spilled gallstones and bile caused postoperative adhesions in this experimental model. An HA derivative significantly prevented postoperative adhesions and decreased breaking strengths. Further clinical studies are needed to validate these findings.

Regulation of postsurgical fibrosis by the programmed death-1 inhibitory pathway

Surgical adhesions are a common and often severe complication of abdominal or pelvic injury that cause pelvic pain, bowel obstruction, and infertility in women. Current treatments are of limited effectiveness because little is known about the cellular and subcellular processes underlying adhesiogenesis. Recently, we showed that Th1 alpha beta CD4(+) T cells mediate the pathogenesis of adhesion formation in a rodent model of this disease process. In this study, we demonstrate that in mice these T cells home directly to the site of surgically induced adhesions and control local chemokine production in a manner dependent on the CD28 T cell costimulatory pathway. Conversely, the inhibitory programmed death-1 pathway plays a central role in limiting adhesiogenesis, as programmed death-1 blockade was associated with increased T cell infiltration, chemokine production, and a concomitant exacerbation of disease. Our results reveal for the first time that the development of postsurgical fibrosis is under the tight control of positive and negative T cell costimulation, and suggest that targeting these pathways may provide promising therapies for the prevention of adhesion formation.

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.

Protective effect of ethyl-3-(3-dimethyl aminopropyl)urea dihydrochloride (EDU) against LPS-induced death in mice

Evaluation of anti-adhesive gels and bioresorbable films in animal models of intra-abdominal infection has shown that a product of the cross-linking reaction between hyaluronic acid (HA) and CM-cellulose, 1-ethyl-3-(3-dimethyl aminopropyl)urea dihydrochloride (EDU), has immunomodulatory properties. The effects of EDU were evaluated by using an endotoxin-induced shock mouse model. Pre-treatment of mice with EDU (50 mg kg(-1)) in DMSO resulted in a significant reduction in mortality following injection of LPS, compared to vehicle (DMSO) pre-treatment alone. Serum levels of TNF-alpha, IL1beta and IFN-gamma in EDU-treated mice were significantly lower than those in vehicle-treated mice. Nitric oxide (NO) concentrations in the sera of mice after inoculation with LPS were significantly lower in the EDU-treated group than in the vehicle-treated group at various time-points. In contrast, EDU pre-treatment was associated with an enhanced IL10 response after LPS injection, compared to vehicle pre-treatment alone. In vitro studies revealed that IL10 production by RAW 264.7 macrophages, elicited by LPS, was increased significantly when EDU was added to the culture medium. These results suggest that the protective effect of EDU during LPS-induced shock in mice is the result of inhibition of proinflammatory cytokines and NO production and an enhanced IL10 response.

Effectiveness of autocrosslinked hyaluronic acid gel after laparoscopic myomectomy in infertile patients: a prospective, randomized, controlled study

OBJECTIVE

To assess the efficacy of autocrosslinked hyaluronic gel in postsurgical adhesion prevention after laparoscopic myomectomy.

DESIGN

Prospective, randomized, controlled study.

SETTING

University of Naples "Federico II".Thirty-six infertile women with symptomatic myomas were randomly divided into two groups of 18 patients each.

INTERVENTION(S)

Laparoscopic myomectomy with subserous sutures or interrupted figure 8 sutures, with (group A) or without (group B) application of autocrosslinked hyaluronic acid (HA) gel.

MAIN OUTCOME MEASURE(S)

Rate of postsurgical adhesions at 60-90 days of follow-up. The rate of subjects who developed postoperative adhesions was significantly lower in group A in comparison with group B (27.8% vs. 77.8%). In both groups, the rate of adhesions was significantly higher in patients treated with interrupted figure 8 sutures than with subserous sutures.

CONCLUSION(S)

Autocrosslinked HA gel is a promising resorbable agent barrier for the reduction of postoperative adhesions after laparoscopic myomectomy. Moreover, the type of suture is a factor influencing the postsurgical adhesion formation.

Tendon surface modification by chemically modified HA coating after flexor digitorum profundus tendon repair

Carbodiimide derivatized HA (cd-HA) is less soluble in water than normal HA, and therefore has an increased tissue residence time. The purpose of this study was to study the effect of cd-HA gel on gliding and repair integrity during simulated repetitive motion of a repaired tendon in vitro. A total of 36 flexor digitorum profundus (FDP) tendons from six adult mongrel dogs were used and divided into three groups of control, simple HA, and cd-HA. The gliding resistance between the FDP and the proximal pulley, FDS, and bone was measured before laceration and after modified Kessler technique repair at 1, 5, 10, 50, 100, 200, 300, 400, and 500 cycles. After gliding testing, failure load, tendon stiffness, and resistance to gap formation were measured. The results showed from the first cycle to the 10th cycle, there were no significant differences in gliding resistance between the three testing groups (p > 0.05). From the 50th cycle onwards, the friction was significantly lower in the cd-HA gel group than in the control group (p < 0.05). Neither breaking strength, nor tendon stiffness, nor resistance to gap formation of the repairs were significantly different between the three groups (p > 0.05).

Seprafilm: a retrospective preliminary evaluation of the impact on short-term oncologic outcome in colorectal cancer

INTRODUCTION

Hyaluronate carboxymethylcellulose-based bioresorbable membrane (Seprafilm ) has been used as a method of postoperative adhesion prevention. However, its short-term effect on colorectal cancer recurrence remains unknown.

METHODS

A retrospective chart review was undertaken of patients with colorectal cancer operated on with curative intent from 1996 to 1999. All patients who received Seprafilm during surgery were assigned to the Seprafilm group, whereas all patients who did not were placed in a control group. Tumor recurrence was defined as persistently elevated carcinoembryonic antigen levels, pathologic confirmation of endoscopic findings, or radiographically documented lesions in the liver, lung, or pelvis.

RESULTS

There were 63 patients in the Seprafilm group and 93 in the control group. The two groups were well matched according to all standard clinical and pathologic characteristics. Adjuvant chemoradiotherapy was administered to 23 patients (36.5 percent) in the Seprafilm group and to 44 (47.3 percent) in the control group ( P= 0.24). At a mean follow-up of 11.4 +/- 7.3 months in the Seprafilm group and 14.2 +/- 11.9 months in the control group, there were 6 (9.5 percent) and 15 (16.1 percent) recurrences, respectively ( P= 0.33). The 1- and 2-year disease-free survival rates were 88 and 85 percent, respectively, in the Seprafilm group and 85 and 72 percent, respectively, in the control group (log-rank test, P= 0.44).

CONCLUSION

Seprafilm did not adversely affect the short-term recurrence rate after curative resection of colorectal cancer. In addition, it did not appear to compromise the short-term oncologic outcome. However, with a short follow-up and a small denominator, a definitive conclusion cannot be drawn. This study does intimate that larger, longer-term, prospective, randomized studies may be safely conducted.

The effectiveness of systemic antibiotics in preventing postoperative, intraabdominal adhesions in an animal model

OBJECTIVE

Postoperative intraabdominal adhesions can be prevented by antibiotic lavage. We assessed whether systemic antibiotics could prevent adhesion formation in a rat model.

METHODS

Cecal abrasion was performed in the peritoneal cavities of 40 Wistar albino rats. Twenty rats were treated with a 5-day course of cefepim and metronidazole; the remaining animals were given saline injections. The animals were sacrificed 14 days after surgery. Adhesion severity scores and histopathologic findings were compared.

RESULTS

The median adhesion severity score was 2 (0-3) in the antibiotic group and 2.5 (1-4) in the controls (P = 0.03). In tissue specimens from controls, the adhesions were marked by mature collagen bundles. In treated rats, the adhesions were immature, characterized by early inflammatory cells, less collagen formation, and no collagen bundles.

CONCLUSIONS

Postoperative systemic antibiotics slow adhesion formation and reduce the severity of the adhesions.

The impact of conventional and laparoscopic colon resection (CO2 or helium) on intraperitoneal adhesion formation in a rat peritonitis model

BACKGROUND

Although postoperative intra-abdominal adhesion formation has been shown to be less with laparoscopic procedures than with open surgery, the extent of intraperitoneal adhesion formation after open and laparoscopic colon resection in patients with intra-abdominal infection remains unclear.

METHODS

A standardized fecal inoculum was intraperitoneally applied in 72 rats to induce peritonitis. The rats were randomized into four groups. The three experimental groups underwent laparoscopic resection of the cecum with carbon dioxide (n = 20) or helium (n = 20) insufflation at a pressure of 8 mmHg, or conventional open cecum resection (n = 20). In the control group, no further manipulations were performed after induction of the peritonitis (n = 12). Blood samples were taken during the perioperative course to determine the plasma levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10). The number of intraperitoneal adhesions and the bacterial species of peritoneal swabs were determined in each animal.

RESULTS

The adhesions were increased in all operation groups as compared with the control group. The number of adhesions was significantly greater after conventional resection than after laparoscopic approaches (p < 0.01). The overall adhesion score was significantly lower in the helium group (p < 0.05) than in the two other operation groups. There was no difference between the laparotomy and carbon dioxide groups. Whereas postoperative TNF-alpha plasma levels were decreased, IL-10 levels were significantly greater in the helium group than in the other three groups.

CONCLUSIONS

Intraperitoneal infection is reducing the benefit of laparoscopic surgery regarding postoperative adhesions. Although laparoscopic resection showed an advantage in the number of adhesions with both gases, the total adhesion score was lowest in the helium group.

Role of a hyaluronate-based membrane in the prevention of peritonitis-induced adhesions

Adhesions remain a significant postoperative complication of abdominal surgery; however, recent evidence suggests that physical barriers may reduce their incidence. Although these adhesion prevention barriers are efficacious when used under aseptic conditions, little is known about their use in the presence of peritonitis, which is associated with an increased incidence of abdominal adhesions. A sodium hyaluronate and carboxymethylcellulose bioresorbable membrane (HA membrane) has been shown recently to reduce postoperative adhesions in several animal models and in two clinical trials. To investigate the efficacy of HA membrane in the presence of peritonitis, generalized peritonitis was induced in rats by either cecal ligation and puncture (CLP) or cecal ligation (CL) alone. The ceca were resected after 12 hours, and animals were randomly assigned to receive or not receive HA membrane applied to the cecum. At day 7, abdominal adhesions and abscesses were scored. In the presence of peritonitis, HA membrane did not significantly reduce the number or tenacity of adhesions. A trend toward increased abscess formation was associated with HA membrane in the CL group. Although HA membrane has been shown to reduce the incidence and severity of abdominal adhesions under aseptic conditions, this study demonstrates that it is not efficacious in preventing abdominal adhesions in the presence of peritonitis. The association between HA membrane and abscess formation in the presence of experimental peritonitis requires further investigation.