Effectiveness and short-term safety of modified sodium hyaluronic acid-carboxymethylcellulose at cesarean delivery: a randomized trial

Effects and safety of hyaluronic acid gel on intrauterine adhesion and fertility after intrauterine surgery: a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials

OBJECTIVE

This study aimed to determine the efficacy and safety of hyaluronic acid gel for the prevention of intrauterine adhesions and improved fertility after intrauterine surgery.

DATA SOURCES

PubMed, EMBASE, Cochrane Library, Web of science, and ClinicalTrials.gov were searched up to November 1, 2023.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that reported intrauterine adhesion and fertility outcomes among women who used hyaluronic acid after intrauterine surgery.

METHODS

The risk of bias was assessed using criteria of the Cochrane Handbook, and the quality of the evidence was evaluated using the Grades of Recommendation, Assessment, Development, and Evaluation system. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. A trial sequential analysis was conducted to assess the outcomes, and Stata 14 was used for sensitivity analyses and publication bias analyses.

RESULTS

Data from 16 randomized controlled trials involving 2359 patients were extracted and analyzed. The analysis revealed that hyaluronic acid reduced the incidence of intrauterine adhesion (risk ratio, 0.53; 95% confidence interval, 0.42-0.67; I2=48%) and improve pregnancy rates (risk ratio, 1.24; 95% confidence interval, 1.02-1.50; I2=0%). A subgroup analysis was conducted to evaluate factors that influence the effect of hyaluronic acid on the incidence of intrauterine adhesion. It was found that a small volume of hyaluronic acid reduced the incidence of intrauterine adhesions. Hyaluronic acid exhibited a protective effect among patients who underwent various intrauterine surgeries and who had different gynecologic medical histories. The protective effect was statistically significant after a follow-up of 6 to 12 weeks. The results of the trial sequential analysis indicated that the effect of hyaluronic acid on the incidence of mild intrauterine adhesions, pregnancy rates, live birth rates, and miscarriage rates after intrauterine surgery may be inconclusive and thus further evaluation is required in the form of additional clinical trials. However, the remaining effects were found to be verifiable and did not require more clinical trials for confirmation.

CONCLUSION

Hyaluronic acid can safely and effectively reduce the incidence of intrauterine adhesions and may improve fertility outcomes.

Intra-operative Guidelines for the Prevention of Uterine Niche Formation in Cesarean Sections: A Review

Formation of a uterine niche following a C-section can predispose the patient to future obstetric complications such as dehiscence, uterine rupture, ectopic pregnancy, and placenta accreta. The significant morbidity and mortality of these complications along with increasing C-section rates emphasizes the importance of prevention. However, there are no clear guidelines on intra-operative protocol to prevent postpartum niche formation. Besides surgical technique, the novel use of platelet-rich plasma (PRP) and mesenchymal stem cell (MSC) injections has demonstrated promising potential and may have applications in hysterotomy closures. The objective is to examine current research on optimal C-section procedures to prevent uterine niche formation and subsequent obstetric complications. A systematic review was conducted using PubMed and Google Scholar. Initial searches yielded 827 results. Inclusion criteria were human, animal, and in-vitro studies, peer-reviewed sources, and outcomes pertinent to the uterine niche. Exclusion criteria applied to articles with outcomes unrelated to myometrium and interventions outside of the intra-operative and immediate pre-/post-operative period. Based on the criteria, 41 articles were cited. Pathophysiology of uterine niche formation was associated with incisions through cervical tissue, adhesion formation, and poor approximation. Significant risk factors were low uterine incisions, advanced cervical dilatation, low station, non-closure of the peritoneum, and creation of a bladder flap. There was no consensus on uterine closure as it likely depends on surgical proficiency with the given technique, but a double-layered non-locking suture appears reliable to reduce niche severity. Recent trials indicate that intra-operative PRP/MSC injections may decrease niche incidence and severity, but more research is needed. If prevention or minimization of uterine niche is desired, the optimal C-section protocol should avoid low uterine incisions, choose uterine closure technique based on the surgeon's proficiency (double-layered non-locking is reliable), and close the peritoneum, and myometrial injection of PRP/MSC may be a useful adjunct intervention pending further clinical evidence.

Adhesion barriers and intraperitoneal or uterine infections after cesarean section: A retrospective cohort study

BACKGROUND

Intraperitoneal adhesion is a common complication of cesarean section, and adhesion barriers are often used to prevent postoperative adhesion. However, the association between the use of adhesion barriers and infections after cesarean section remains unknown. This study aimed to evaluate the association.

METHODS

Using the administrative claims database of a single prefecture in Japan, we identified all patients who underwent cesarean section from June 2014 to February 2019. A multivariable logistic regression model fitted with a generalized estimating equation was used to compare the postoperative outcomes between patients who received intraperitoneal adhesion barriers during cesarean section and those who did not. The primary outcome was intraperitoneal or uterine infections within 3 months after cesarean section, including intraperitoneal abscess, pelvic inflammatory disease, peritonitis, uterine wound infection, endometritis, and adnexitis.

RESULTS

A total of 1,392 patients with 1,498 cesarean section cases were reviewed. Adhesion barriers were used in 1,153/1,498 (77.0%) cases. One hundred and fourteen (9.9%) intraperitoneal or uterine infections occurred in the group with and 15 (4.3%) in the group without adhesion barriers. The proportion of intraperitoneal or uterine infections was significantly higher in the group with than in the group without adhesion barriers (9.9% and 4.3%, respectively; adjusted odds ratio = 2.59; 95% confidence interval, 1.40-4.77; P = .002).

CONCLUSION

The use of adhesion barriers was associated with an increase in intraperitoneal or uterine infections after cesarean section.

Adhesion barriers and topical hemostatic agents are risk factors for post-cesarean section infections

BACKGROUND

Cesarean sections are the most common surgery worldwide, and post-cesarean section infections and hemorrhage are a major cause for morbidity and mortality. In recent years, many surgeons use adhesion barriers as well as hemostatic agents during primary and repeated cesarean section. The data regarding the safety of these agents is relatively limited. The objective of this study was to investigate whether the use of adhesion barriers and topical hemostatic agents pose a risk for post-cesarean section infections.

METHOD

A case-control study composed of women who were admitted to the Soroka University Medical Center between the years 2012 and 2016 was conducted. The study group was composed of women admitted owing to post-cesarean section infections (cases) and those who underwent cesarean sections without post-cesarean section infection (control subjects). Matching was done according to date and surgery setting (elective versus emergency). A univariate analysis was followed by a multiple regression model in order to examine the association between adhesion barriers/hemostatic agents and post-cesarean section infections.

RESULTS

During the study period, 113 patients developed postoperative infection (cases); 71.7% were diagnosed with surgical site infection, 7.1% with endometritis, and 21.2% with other infections. These were compared with 226 control subjects. In the univariate analysis, the use of adhesion barriers/hemostatic agents were found to be associated with post-cesarean section infection. Using a multivariable analysis controlling for previous cesarean section, skin closer technique, preterm delivery, and duration of surgery >60 minutes, the use of adhesion barriers as well as hemostatic agents was found to be independently associated with post-cesarean section infection (adjusted odds ratio = 2.11, 95% confidence interval = 1.17-3.84; adjusted odds ratio = 2.29, 95% confidence interval = 1.37-3.8, respectively) CONCLUSION: Adhesion barriers and hemostatic agents were found to be independently associated with post-cesarean section infections. Further larger studies are needed to reinforce our findings. The use of these materials should be carefully considered, and their cost-effectiveness re-examined.

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.

Cesarean delivery: an evidence-based review of the technique

The cesarean section is utilized to deliver babies since the late 19^th century. Nowadays, the frequency of cesarean section is increased, mainly because of the low rate of complications and for the increasing demand from future mothers, scared by the idea of painful labor. Although the technique to perform cesarean section has been refined over time, infections, hemorrhage, pain and other consequences still represent matter of debate. To try to reduce the incidence of these complications many trials, randomized or not, have been performed, with the aim to analyze different technical aspects of this surgery. The aim of our review was to resume all the evidence-based instructions on how to best approach to cesarean section practice, in a step-to-step fashion, considering pre-operative actions, opening and closing steps, and postoperative prophylaxis.

[Existing and forward-looking ways to prevent adhesions in IPOM hernia repair. A research overview]

IPOM intraperitoneal hernia repair, in comparison with other abdominal wall reconstruction methods, has a number of significant advantages. Among them are a reduction in operative time, low rate of surgical site infections, quick rehabilitation, and good cosmetic results. At the same time, one of the main constraining factors for its widespread use is the rather high frequency of adhesion formation between the implant and the abdominal organs. The first way to solve this serious problem is to improve the structure of the implant itself, and in the first place, its anti-adhesive layer. The second is the search for adjuvant tools that work in «problematic» areas, prone to adhesions formation, such as the points of implant fixation, its edges, or the areas of damage to antiadhesive layer due to a violation of the operative technique. It is desirable that they could exert their effect also in other parts of the abdominal cavity, which, despite the absence of a zone of «active» intervention, can also undergo adhesions. Based on this, the purpose of this review was to summarize modern data on the anti-adhesive activity of both composite implants and specialized membranes and liquid agents.

The use of absorbable adhesion barriers to reduce the incidence of intraperitoneal adhesions at repeat cesarean delivery

PURPOSE

We aimed to evaluate the effect of an absorbable adhesion barrier (oxidized regenerated cellulose) for the prevention of peritoneal adhesions in women undergoing repeat cesarean delivery (CD).

METHODS

This is a retrospective, single center study that included all women who underwent two consecutive CDs, 2011-2018. Women in whom an absorbable adhesion barrier (oxidized regenerated cellulose) was placed at the time of the initial CD (index CD) were compared to women in whom no such barrier was placed. The association between absorbable adhesion barrier placement at index CD and the presence of intraperitoneal adhesions at subsequent CD was assessed. Factors evaluated included intraperitoneal adhesion severity, time from skin incision to newborn delivery and total duration of surgery.

RESULTS

We identified 2125 women that met the inclusion criteria. They were divided into two groups; those in whom an absorbable adhesion barrier was placed at index CD and those in whom no such absorbable barrier was placed. 161 (7.6%) had an absorbable adhesion barrier placed at index CD. At the time of index CD, the rate of intra-peritoneal adhesions was 34.8% in the absorbable adhesion barrier group vs 26.5% in the group without the absorbable adhesion barrier (p = 0.02). At the time of subsequent CD, the rate of intraperitoneal adhesions was 39.8% in the absorbable adhesion barrier group vs 46% in the group without the absorbable adhesion barrier (p = 0.13). Notably, the use of an absorbable adhesion barrier lowered the mean increase in adhesions rate 0.05 ± 0.55 vs 0.20 ± 0.55 (p < 0.01). Absorbable adhesion barrier placement at index CD was found to be independently associated with a lower rate of intraperitoneal adhesions at subsequent CD, aOR 0.67 (0.47-0.96). Overall, absorbable adhesion barrier placement at index CD was associated with a shorter mean duration of subsequent surgery (min), 37.7 ± 18.9 vs. 42.7 ± 27.1 (p = 0.02).

CONCLUSION

Absorbable adhesion barrier placement is associated with reduction in intraperitoneal adhesions and duration of surgery in subsequent CD.

The sticky business of adhesion prevention in minimally invasive gynecologic surgery

PURPOSE OF REVIEW

The negative impact of postoperative adhesions has long been recognized, but available options for prevention remain limited. Minimally invasive surgery is associated with decreased adhesion formation due to meticulous dissection with gentile tissue handling, improved hemostasis, and limiting exposure to reactive foreign material; however, there is conflicting evidence on the clinical significance of adhesion-related disease when compared to open surgery. Laparoscopic surgery does not guarantee the prevention of adhesions because longer operative times and high insufflation pressure can promote adhesion formation. Adhesion barriers have been available since the 1980s, but uptake among surgeons remains low and there is no clear evidence that they reduce clinically significant outcomes such as chronic pain or infertility. In this article, we review the ongoing magnitude of adhesion-related complications in gynecologic surgery, currently available interventions and new research toward more effective adhesion prevention.

RECENT FINDINGS

Recent literature provides updated epidemiologic data and estimates of healthcare costs associated with adhesion-related complications. There have been important advances in our understanding of normal peritoneal healing and the pathophysiology of adhesions. Adhesion barriers continue to be tested for safety and effectiveness and new agents have shown promise in clinical studies. Finally, there are many experimental studies of new materials and pharmacologic and biologic prevention agents.

SUMMARY

There is great interest in new adhesion prevention technologies, but new agents are unlikely to be available for clinical use for many years. High-quality effectiveness and outcomes-related research is still needed.

Postoperative Abdominal Adhesions: Clinical Significance and Advances in Prevention and Management

Postoperative adhesions remain one of the more challenging issues in surgical practice. Although peritoneal adhesions occur after every abdominal operation, the density, time interval to develop symptoms, and clinical presentation are highly variable with no predictable patterns. Numerous studies have investigated the pathophysiology of postoperative adhesions both in vitro and in vivo. Factors such as type and location of adhesions, as well as timing and recurrence of adhesive obstruction remain unpredictable and poorly understood. Although the majority of postoperative adhesions are clinically silent, the consequences of adhesion formation can represent a lifelong problem including chronic abdominal pain, recurrent intestinal obstruction requiring multiple hospitalizations, and infertility. Moreover, adhesive disease can become a chronic medical condition with significant morbidity and no effective therapy. Despite recent advances in surgical techniques, there is no reliable strategy to manage postoperative adhesions. We herein review the pathophysiology and clinical significance of postoperative adhesions while highlighting current techniques of prevention and treatment.

Injectable thermosensitive hydrogel containing hyaluronic acid and chitosan as a barrier for prevention of postoperative peritoneal adhesion

Peritoneal adhesion is one of the common complications after abdominal surgery. Injectable thermosensitive hydrogel could serve as an ideal barrier to prevent this postoperative tissue adhesion. In this study, poly(N-isopropylacrylamide) (PNIPAm) was grafted to chitosan (CS) and the polymer was further conjugated with hyaluronic acid (HA) to form thermosensitive HA-CS-PNIPAm hydrogel. Aqueous solutions of PNIPAm and HA-CS-PNIPAm at 10%(w/v) are both free-flowing and injectable at room temperature and exhibit sol-gel phase transition around 31°C; however, HA-CS-PNIPAm shows less volume shrinkage after gelation and higher complex modulus than PNIPAm. Cell culture studies indicate both injectable hydrogel show barrier effects to reduce fibroblasts penetration while induce little cytotoxicity in vitro. From a sidewall defect-bowel abrasion model in rats, significant reduction of postoperative peritoneal adhesion was found for peritoneal defects treated with HA-CS-PNIPAm compared with those treated with PNIPAm and untreated controls from gross and histological evaluation. Furthermore, HA-CS-PNIPAm did not interfere with normal peritoneal tissue healing and did not elicit acute toxicity from blood analysis and tissue biopsy examination. By taking advantage of the easy handling and placement properties of HA-CS-PNIPAm during application, this copolymer hydrogel would be a potentially ideal injectable anti-adhesion barrier after abdominal surgeries.

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.

Dressings for the prevention of surgical site infection

BACKGROUND

Surgical wounds (incisions) heal by primary intention when the wound edges are brought together and secured, often with sutures, staples, or clips. Wound dressings applied after wound closure may provide physical support, protection and absorb exudate. There are many different types of wound dressings available and wounds can also be left uncovered (exposed). Surgical site infection (SSI) is a common complication of wounds and this may be associated with using (or not using) dressings, or different types of dressing.

OBJECTIVES

To assess the effects of wound dressings compared with no wound dressings, and the effects of alternative wound dressings, in preventing SSIs in surgical wounds healing by primary intention.

SEARCH METHODS

We searched the following databases: the Cochrane Wounds Specialised Register (searched 19 September 2016); the Cochrane Central Register of Controlled Trials (CENTRAL; the Cochrane Library 2016, Issue 8); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations, MEDLINE Daily and Epub Ahead of Print; 1946 to 19 September 2016); Ovid Embase (1974 to 19 September 2016); EBSCO CINAHL Plus (1937 to 19 September 2016).There were no restrictions based on language, date of publication or study setting.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing wound dressings with wound exposure (no dressing) or alternative wound dressings for the postoperative management of surgical wounds healing by primary intention.

DATA COLLECTION AND ANALYSIS

Two review authors performed study selection, 'Risk of bias' assessment and data extraction independently.

MAIN RESULTS

We included 29 trials (5718 participants). All studies except one were at an unclear or high risk of bias. Studies were small, reported low numbers of SSI events and were often not clearly reported. There were 16 trials that included people with wounds resulting from surgical procedures with a 'clean' classification, five trials that included people undergoing what was considered 'clean/contaminated' surgery, with the remaining studies including people undergoing a variety of surgical procedures with different contamination classifications. Four trials compared wound dressings with no wound dressing (wound exposure); the remaining 25 studies compared alternative dressing types, with the majority comparing a basic wound contact dressing with film dressings, silver dressings or hydrocolloid dressings. The review contains 11 comparisons in total.

PRIMARY OUTCOME

SSIIt is uncertain whether wound exposure or any dressing reduces or increases the risk of SSI compared with alternative options investigated: we assessed the certainty of evidence as very low for most comparisons (and low for others), with downgrading (according to GRADE criteria) largely due to risk of bias and imprecision. We summarise the results of comparisons with meta-analysed data below:- film dressings compared with basic wound contact dressings following clean surgery (RR 1.34, 95% CI 0.70 to 2.55), very low certainty evidence downgraded once for risk of bias and twice for imprecision.- hydrocolloid dressings compared with basic wound contact dressings following clean surgery (RR 0.91, 95% CI 0.30 to 2.78), very low certainty evidence downgraded once for risk of bias and twice for imprecision.- hydrocolloid dressings compared with basic wound contact dressings following potentially contaminated surgery (RR 0.57, 95% CI 0.22 to 1.51), very low certainty evidence downgraded twice for risk of bias and twice for imprecision.- silver-containing dressings compared with basic wound contact dressings following clean surgery (RR 1.11, 95% CI 0.47 to 2.62), very low certainty evidence downgraded once for risk of bias and twice for imprecision.- silver-containing dressings compared with basic wound contact dressings following potentially contaminated surgery (RR 0.83, 95% CI 0.51 to 1.37), very low certainty evidence downgraded twice for risk of bias and twice for imprecision. Secondary outcomesThere was limited and low or very low certainty evidence on secondary outcomes such as scarring, acceptability of dressing and ease of removal, and uncertainty whether wound dressings influenced these outcomes.

AUTHORS' CONCLUSIONS

It is uncertain whether covering surgical wounds healing by primary intention with wound dressings reduces the risk of SSI, or whether any particular wound dressing is more effective than others in reducing the risk of SSI, improving scarring, reducing pain, improving acceptability to patients, or is easier to remove. Most studies in this review were small and at a high or unclear risk of bias. Based on the current evidence, decision makers may wish to base decisions about how to dress a wound following surgery on dressing costs as well as patient preference.