Pressure transduction and fluid evacuation during conventional negative pressure wound therapy of the open abdomen and NPWT using a protective disc over the intestines

Application and Prognostic Analysis of Vacuum Sealing Drainage in the Incision Infection in Patients With Stage II-III Colorectal Cancer

INTRODUCTION

This study aims to explore the application value of vacuum sealing drainage (VSD) technology in the treatment of incision infection dehiscence after surgery in patients with stage II-III colorectal cancer and analyze its impact on prognosis.

METHODS

This retrospective study included patients who experienced incision infection dehiscence after surgery for colorectal cancer between February 2014 and August 2019. Clinical and pathological data, short-term outcomes, and long-term outcomes were compared between the traditional group and the VSD group.

RESULTS

A total of 97 patients were included in this study. There was no significant difference in clinical and pathological data between the traditional group and the VSD group (P > 0.05). The VSD group had fewer dressing changes, lower pain scores during dressing changes, and better granulation tissue growth grading than the traditional group, with statistical significance (P < 0.05). The VSD group started adjuvant chemotherapy earlier and had a higher proportion of ≥4 cycles of chemotherapy. The three-year overall survival rate in the VSD group was better than the traditional group, but the difference was not statistically significant (P > 0.05).

CONCLUSION

The application of VSD technology can promote granulation tissue growth, accelerate incision healing, and facilitate patients to complete subsequent adjuvant chemotherapy. However, further verification of its long-term impact on prognosis requires longer-term follow-up results.

Optimal tentative abdominal closure for open abdomen: a multicenter retrospective observational study (OPTITAC study)

BACKGROUND

Primary fascia closure is often difficult following an open abdomen (OA). While negative-pressure wound therapy (NPWT) is recommended to enhance successful primary fascia closure, the optimal methods and degree of negative pressure remain unclear. This study aimed to elucidate optimal methods of NPWT as a tentative abdominal closure for OA to achieve primary abdominal fascia closure.

MATERIALS AND METHODS

A multicenter, retrospective, cohort study of adults who survived OA greater than 48 h was conducted in 12 institutions between 2010 and 2022. The achievement of primary fascia closure and incidence of enteroatmospheric fistula were examined based on methods (homemade, superficial NPWT kit, or open-abdomen kit) or degrees of negative pressure (<50, 50-100, or >100 mmHg). A generalized estimating equation was used to adjust for age, BMI, comorbidities, etiology for laparotomy requiring OA, vital signs, transfusion, severity of critical illness, and institutional characteristics.

RESULTS

Of the 279 included patients, 252 achieved primary fascia closure. A higher degree of negative pressure (>100 mmHg) was associated with fewer primary fascia closures than less than 50 mmHg [OR, 0.18 (95% CI: 0.50-0.69), P =0.012] and with more frequent enteroatmospheric fistula [OR, 13.83 (95% CI: 2.30-82.93)]. The methods of NPWT were not associated with successful primary fascia closure. However, the use of the open-abdomen kit was related to a lower incidence of enteroatmospheric fistula [OR, 0.02 (95% CI: 0.00-0.50)].

CONCLUSION

High negative pressure (>100 mmHg) should be avoided in NPWT during tentative abdominal closure for OA.

Subvacuum environment-enhanced cell migration promotes wound healing without increasing hypertrophic scars caused by excessive cell proliferation

Cell migration and proliferation are conducive to wound healing; however, regulating cell proliferation remains challenging, and excessive proliferation is an important cause of scar hyperplasia. Here, we aimed to explore how a subvacuum environment promotes wound epithelisation without affecting scar hyperplasia. Human immortalized keratinocyte cells and human skin fibroblasts were cultured under subvacuum conditions (1/10 atmospheric pressure), and changes in cell proliferation and migration, target protein content, calcium influx, and cytoskeleton and membrane fluidity were observed. Mechanical calcium (Ca2+ ) channel blockers were used to prevent Ca2+ influx for reverse validation. A rat wound model was used to elucidate the mechanism of the subvacuum dressing in promoting healing. The subvacuum environment was observed to promote cell migration without affecting cell proliferation; intracellular Ca2+ concentrations and PI3K, p-PI3K, AKT1, p-AKT 1 levels increased significantly. The cytoskeleton was depolymerized, pseudopodia were reduced or absent, and membrane fluidity increased. The use of Ca2+ channel blockers weakened or eliminated these changes. Animal experiments confirmed these phenomena and demonstrated that subvacuum dressings can effectively promote wound epithelisation. Our study demonstrates that the use of subvacuum dressings can enhance cell migration without affecting cell proliferation, promote wound healing, and decrease the probability of scar hyperplasia.

The Effect of Negative Pressure in the Abdominal Cavity With Suprasorb CNP on Abdominal Organs-An Experimental Study

Since the introduction of negative pressure therapy of the abdomen, care has been taken to protect the intestine from the effects of negative pressure in order to avoid impairments of abdominal organs. As an alternative to the widespread AB-Thera^R system (KCI, San Antonio, Texas, USA), the different concept of Suprasorb CNP^R (Lohmann & Rauscher, Austria-Germany) was introduced by the producer with the premise of achieving a better therapeutic effect. Due to numerous pores of the film, the effects of the negative pressure are brought to the surface of the intestinal organs and these effects were tested on seven experimental animals. Particular attention was paid to the small intestine, colon, liver, and pancreas. Over 8 h continuously, three animals were tested with −80 mmHg, 4 with −60 mmHg. The results showed no macroscopic pathological changes. The histological results showed borderline changes in the small intestine and colon with −80 mmHg application, minimal or none with −60 mmHg. The liver and pancreas were found free of pathological changes. For use on human organs, the intra-abdominal application of −60 mmHg for the Suprasorb CNP system is proposed as the standard.

The impact of standardized protocol implementation for surgical damage control and temporary abdominal closure after emergent laparotomy

BACKGROUND

To standardize care and promote early fascial closure among patients undergoing emergent laparotomy and temporary abdominal closure (TAC), we developed a protocol addressing patient selection, operative technique, resuscitation strategies, and critical care provisions. We hypothesized that primary fascial closure rates would increase following protocol implementation with no difference in complication rates.

STUDY DESIGN

We performed a retrospective cohort analysis of 138 adult trauma and emergency general surgery patients who underwent emergent laparotomy and TAC, comparing protocol patients (n = 60) to recent historic controls (n = 78) who would have met protocol inclusion criteria. The protocol includes low-volume 3% hypertonic saline resuscitation, judicious wound vacuum fluid replacement, and early relaparotomy with sequential fascial closure. Demographics, baseline characteristics, illness severity, resuscitation course, operative management, and outcomes were compared. The primary outcome was fascial closure.

RESULTS

Baseline characteristics, including age, American Society of Anesthesiologists class, and postoperative lactate levels, were similar between groups. Within 48 hours of initial laparotomy and TAC, protocol patients received significantly lower total intravenous fluid resuscitation volumes (9.7 vs. 11.4 L, p = 0.044) and exhibited higher serum osmolarity (303 vs. 293 mOsm/kg, p = 0.001). The interval between abdominal operations was significantly shorter following protocol implementation (28.2 vs. 32.2 hours, p = 0.027). The incidence of primary fascial closure was significantly higher in the protocol group (93% vs. 81%, p = 0.045, number needed to treat = 8.3). Complication rates were similar between groups.

CONCLUSIONS

Protocol implementation was associated with lower crystalloid resuscitation volumes, a transient hyperosmolar state, shorter intervals between operations, and higher fascial closure rates with no difference in complications.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Chinese Trauma Surgeon Association for management guidelines of vacuum sealing drainage application in abdominal surgeries-Update and systematic review

Vacuum sealing drainage (VSD) is frequently used in abdominal surgeries. However, relevant guidelines are rare. Chinese Trauma Surgeon Association organized a committee composed of 28 experts across China in July 2017, aiming to provide an evidence-based recommendation for the application of VSD in abdominal surgeries. Eleven questions regarding the use of VSD in abdominal surgeries were addressed: (1) which type of materials should be respectively chosen for the intraperitoneal cavity, retroperitoneal cavity and superficial incisions? (2) Can VSD be preventively used for a high-risk abdominal incision with primary suture? (3) Can VSD be used in severely contaminated/infected abdominal surgical sites? (4) Can VSD be used for temporary abdominal cavity closure under some special conditions such as severe abdominal trauma, infection, liver transplantation and intra-abdominal volume increment in abdominal compartment syndrome? (5) Can VSD be used in abdominal organ inflammation, injury, or postoperative drainage? (6) Can VSD be used in the treatment of intestinal fistula and pancreatic fistula? (7) Can VSD be used in the treatment of intra-abdominal and extra-peritoneal abscess? (8) Can VSD be used in the treatment of abdominal wall wounds, wound cavity, and defects? (9) Does VSD increase the risk of bleeding? (10) Does VSD increase the risk of intestinal wall injury? (11) Does VSD increase the risk of peritoneal adhesion? Focusing on these questions, evidence-based recommendations were given accordingly. VSD was strongly recommended regarding the questions 2-4. Weak recommendations were made regarding questions 1 and 5-11. Proper use of VSD in abdominal surgeries can lower the risk of infection in abdominal incisions with primary suture, treat severely contaminated/infected surgical sites and facilitate temporary abdominal cavity closure.

Virulence analysis of Staphylococcus aureus in a rabbit model of infected full-thickness wound under negative pressure wound therapy

The aim of this study was to evaluate the virulence of Staphylococcus aureus in a controlled animal study using the standard sterile gauze and negative pressure wound therapy (NPWT), including activation of agr, gene expression and production of virulence foctors and depth of bacterial invasion. The tissue specimens were harvested on days 0 (6 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds. Laser scanning confocal microscopy was performed to obtain bioluminescent images which were used to measure the depth of bacterial invasion. The agrA expression of S.aureus and the transcription and production of virulence factors including Eap, Spa and α-toxin were significantly different. The bacterial invasion depth was significantly less with effect of NPWT. The markedly different activation of quorum sensing systems that enable cell-to-cell communication and regulation of numerous colonization and virulence factors result in distinct gene expression and pathogenicity over time in different microenvironment. Thus, the agr system represents a fundamental regulatory paradigm that can encompass different adaptive strategies and accommodate horizontally acquired virulence determinants.

Prophylactic vacuum sealing drainage (VSD) in the prevention of postoperative surgical site infections in pediatric patients with contaminated laparotomy incisions

Surgical site infection (SSI) continues to be an issue in abdominal surgery, especially for contaminated (class III) and dirty-infected (class IV) wounds. Vacuum sealing drainage (VSD) was reported effective in the management of various types of wounds or skin grafts. Our goal was to investigate the efficacy of prophylactic VSD to better orient their medicosurgical care of high-risk incisions following laparotomy in a pediatric population.A total of 331 pediatric patients with contaminated (class III) and dirty-infected (class IV) wounds following emergency laparotomy were retrospectively reviewed between January 2005 and January 2013. Among them, 111 cases were placed with prophylactic VSD when incisions were closed. Clinical outcomes, including, overall surgical site complication, device effectiveness, and mean postoperative LOS were evaluated based on VSD usage or not.VSD was applied for an average of 5.8 days (range, 5-7 days), with 3 to 15 mL sucked fluid. The overall SSIs rate was 3% for patients with prophylactic VSD and 17% for patients with convention dressing (OR, 0.27; 95% CI, 0.10-0.71, P = 0.004). In patients with prophylactic VSD, only 1 of 96 wound developed postoperative incision dehiscence, which is significant reduced compared with patients for conventional dressings (OR, 0.12; 95% CI, 0.01-0.95; P = 0.017) (Table 2). It also exhibited a decreased mean postoperative LOS (P < 0.001) for prophylactic VSD over conventional dressings.Our study demonstrated beneficial postoperative clinical effects of prophylactic VSD for high-risk laparotomy incisions following emergency laparotomy, such as shorter length of hospitalization, which may be attributed to the reduced overall SSIs rate.

The Open Abdomen Route by EuraHS: introduction of the data set and initial results of procedures and procedure-related complications

INTRODUCTION

Open abdomen management has become a well-established strategy in the treatment of serious intra-abdominal pathologies. Key objectives are fistula prevention and high fascial closure rates. The current level of evidence on laparostoma is insufficient. This is due to the rareness of laparostomas, the heterogeneity of study cohorts, and broad diversity of techniques. Collecting data in a standardised, multicentre registry is necessary to draw up evidence-based guidelines.

MATERIALS AND METHODS

In order to improve the level of evidence on laparostomy, CAMIN (surgical working group for military and emergency surgery) of DGAV (German Society for General and Visceral Surgery), initiated the implementation of a laparostomy registry. This registry was established as the Open Abdomen Route by EuraHS (European Registry of Abdominal Wall Hernias). Key objectives include collection of data, quality assurance, standardisation of therapeutic concepts and the development of guidelines. Since 1 May 2015, the registry is available as an online database called Open Abdomen Route of EuraHS (European Registry of Abdominal Wall Hernias). It includes 11 categories for data collection, including three scheduled follow-up examinations.

RESULTS

As part of this pilot study, all entries of the first 120 days were analysed, resulting in a review of 82 patients. At 44%, secondary peritonitis was the predominant indication. The mortality rate was 22%. A comparison of methods with and without fascial traction reveals fascial closure rates of 67% and 25%, respectively (intention-to-treat analysis, p < 0.03). Inert visceral protection was used in 67% of patients and achieved a small bowel fistula incidence of only 5.5%.

DISCUSSION

Optimising laparostomy management techniques in order to achieve low incidence of fistulation and high fascial closure rates is possible. The method that ensures the best possible outcome-based on current evidence-would involve fascial traction, visceral protection and negative pressure. The laparostomy registry is a useful tool for quickly generating sufficient evidence for open abdomen treatment.

Systematic review and evidence based recommendations for the use of negative pressure wound therapy in the open abdomen

INTRODUCTION

Negative Pressure Wound Therapy (NPWT) is widely used in the management of the open abdomen despite uncertainty regarding several aspects of usage. An expert panel was convened to develop evidence-based recommendations describing the use of NPWT in the open abdomen.

METHODS

A systematic review was carried out to investigate the efficacy of a range of Temporary Abdominal Closure methods including variants of NPWT. Evidence-based recommendations were developed by an International Expert Panel and graded according to the quality of supporting evidence.

RESULTS

Pooled results, in non-septic patients showed a 72% fascial closure rate following use of commercial NPWT kits in the open abdomen. This increased to 82% by the addition of a 'dynamic' closure method. Slightly lower rates were showed with use of Wittmann Patch (68%) and home-made NPWT (vac-pack) (58%). Patients with septic complications achieved a lower rate of fascial closure than non-septic patients but NPWT with dynamic closure remained the best option to achieve fascial closure. Mortality rates were consistent and seemed to be related to the underlying medical condition rather than being influenced by the choice of dressing, Treatment goals for open abdomen were defined prior to developing eleven specific evidence-based recommendations suitable for different stages and grades of open abdomen.

DISCUSSION AND CONCLUSION

The most efficient temporary abdominal closure techniques are NPWT kits with or without a dynamic closure procedure. Evidence-based recommendations will help to tailor its use in a complex treatment pathway for the individual patient.

Matching biological mesh and negative pressure wound therapy in reconstructing an open abdomen defect

Reconstruction of open abdominal defects is a clinical problem which general and plastic surgeons have to address in cooperation. We report the case of a 66-year-old man who presented an abdominal dehiscence after multiple laparotomies for a sigmoid-rectal adenocarcinoma that infiltrated into the abdominal wall, subsequently complicated by peritonitis and enteric fistula. A cutaneous dehiscence and an incontinent abdominal wall resulted after the last surgery. The abdominal wall was reconstructed using a biological porcine cross-linked mesh Permacol (Covidien Inc., Norwalk, CT). Negative Pressure Wound Therapy (NPWT), instead, was used on the mesh in order to reduce wound dimensions, promote granulation tissue formation, and obtain secondary closure of cutaneous dehiscence which was finally achieved with a split-thickness skin graft. Biological mesh behaved like a scaffold for the granulation tissue that was stimulated by the negative pressure. The biological mesh was rapidly integrated in the abdominal wall restoring abdominal wall continence, while the small dehiscence, still present in the central area, was subsequently covered with a split-thickness skin graft. The combination of these different procedures led us to solve this complicated case obtaining complete wound closure after less than 2 months.

Comparative study of the microvascular blood flow in the intestinal wall, wound contraction and fluid evacuation during negative pressure wound therapy in laparostomy using the V.A.C. abdominal dressing and the ABThera open abdomen negative pressure therapy system

This study aimed to compare the changes in microvascular blood flow in the small intestinal wall, wound contraction and fluid evacuation, using the established V.A.C. abdominal dressing (VAC dressing) and a new abdominal dressing, the ABThera open abdomen negative pressure therapy system (ABThera dressing), in negative pressure wound therapy (NPWT). Midline incisions were made in 12 pigs that were subjected to treatment with NPWT using the VAC or ABThera dressing. The microvascular blood flow in the intestinal wall was measured before and after the application of topical negative pressures of −50, −75 and −125mmHg using laser Doppler velocimetry. Wound contraction and fluid evacuation were also measured. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced to 64·6±6·7% (P <0·05) after the application of −50mmHg using the VAC dressing, and to 65·3±9·6% (P <0·05) after the application of −50mmHg using the ABThera dressing. The blood flow was significantly reduced to 39·6±6·7% (P <0·05) after the application of −125mmHg using VAC and to 40·5±6·2% (P <0·05) after the application of −125mmHg using ABThera. No significant difference in reduction in blood flow could be observed between the two groups. The ABThera system afforded significantly better fluid evacuation from the wound, better drainage of the abdomen and better wound contraction than the VAC dressing.