Comparison between the Intraoperative Use of ...

Eur Surg Res 2013;50:44–55 DOI: 10.1159/000348409 Received: December 18, 2012 Accepted after revision: January 20, 2013 Published online: March 29, 2013

© 2013 S. Karger AG, Basel 0014–312X/13/0501–0044$38.00/0 www.karger.com/esr

Original Paper

Comparison between the Intraoperative Use of Polyvinyl Chloride Cover and Surgical Compresses for Preventing Postoperative Adhesions C. Akyol a U. Sozener a A. Ozgun b A. Karabork b A.B. Erkek a E. Erdemli c M.A. Kuzu a

I. Kuzu b

A. Cakmak a

Departments of a Surgery, b Pathology and c Histology and Embryology, Ankara University School of Medicine, Ankara, Turkey

Key Words Adhesion formation · Inflammation · Rats · Surgery Abstract Background/Purpose: Surgical compresses used for retraction during major abdominal and pelvic procedures lead to postoperative adhesion formation resulting from damage to the visceral peritoneum. This study investigates whether polyvinyl chloride (PVC) covers cause less postsurgical adhesion and inflammation than surgical compresses in an animal model. Methods: Female Wistar albino rats (n = 160) were divided into three groups (compress, PVC cover and control), which were then divided into 16 subgroups (n = 10/group). All animals underwent midline laparotomy and cecal abrasion. A metal retractor, which applies a constant force, was then placed on the small intestine for 2 h. In the control group, no material was placed under the retractor, whereas a surgical compress or PVC cover was placed in the experimental animals. Full-thickness small intestinal biopsies were obtained and examined by light and electron microscopy. The following parameters were evaluated: congestion, mesothelial proliferation, leukocyte migration and collagenization. Adhesions were scored according to the Nair, Knightly and Mazuji scoring systems. Results: All inflammation scores were significantly higher in the compress group than in the other two groups. However, no significant difference was observed between the PVC cover and control groups. Adhesions were more frequent in the compress group than in the other two groups, regardless of the scoring system used. Conclusions: Surgical compresses used in abdominal and pelvic surgeries cause inflammation and adhesion. Contrary to surgical compresses, PVC covers do not cause inflammation and adhesion, which may considerably reduce adhesion-related complications in abCopyright © 2013 S. Karger AG, Basel dominopelvic surgeries. Cihangir Akyol, MD Ankara Universitesi Tıp Fakultesi Genel Cerrahi Anabilim Dalı TR–06100 Sıhhıye, Ankara (Turkey) E-Mail cihangirakyol @ gmail.com

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Eur Surg Res 2013;50:44–55 DOI: 10.1159/000348409

© 2013 S. Karger AG, Basel www.karger.com/esr

Akyol et al.: Comparison between the Intraoperative Use of Polyvinyl Chloride Cover and Surgical Compresses for Preventing Postoperative Adhesions

Introduction

Intra-abdominal adhesions, which may occur because of endometriosis, infections, chemotherapy, radiation or malignancies [1], mainly occur following abdominopelvic surgery and have significant unfavorable effects on the patient’s quality of life [2]. Specific inflammatory responses activated by intraoperative damage are necessary for tissue healing [3, 4]. Although the etiology of adhesions has not been completely elucidated, some risk factors have been identified, including intraoperative tissue damage, tissue hypoxia and devascularization-related ischemia, blunt dissection of previous adhesions, drying of the tissue and serosal surface, reactive foreign bodies such as suture material and powder, and the presence of intraperitoneal blood and clotting. Surgical compresses are used to retract the abdominal organs during major abdominal and pelvic surgeries and can play a significant role in the formation of postoperative intraabdominal adhesion because they cause both traumatic abrasions and foreign body granuloma formation caused by the release of particles into the abdominal cavity. The development of adhesions follows tissue inflammation, fibrin deposition, fibrin organization, collagen formation, and maturation processes [5, 6]. Pathological fibrous bands and newly formed capillaries cause permanent fibrotic adhesion between two peritoneal surfaces when at least one has mesothelial damage because the exudate, which is released several hours after the operation, is absorbed [7, 8]. Intraperitoneal adhesions are important causes of morbidity and mortality and lead to numerous complications such as obstruction of the small intestine [9], intra-abdominal abscesses, ureteral obstruction, chronic pain [10] and infertility [11, 12]. Postoperative adhesions develop after 90% of all laparotomies [9, 13] and the above-mentioned complications indicate the importance of identifying the etiological factors in adhesion formation. To date, numerous agents have been identified as surgical adjuvants and can be categorized in four main groups: fibrin deposition inhibitors, fibrin exudate removers, mechanical separators of visceral surfaces, and fibroblastic proliferation inhibitors [14, 15]. However, these agents are not completely effective either because of associated complications or their inability to completely prevent adhesions. Therefore, the use of surgical procedures causing minimum damage has increased. In this context, polyvinyl chloride (PVC) covers, which are known as a ‘Bogota bags’ in the literature, are applied frequently in temporary abdominal closure techniques [16] as an alternative material to surgical compresses to prevent abrasions resulting from the attachment of the surgical compresses to the intestinal serosa and related adhesions. In the present study, we compared the effects of the use of surgical compresses and PVC covers on adhesion development.

Methods The present study was conducted at the Surgical Operation Laboratory, Department of Pharmacology and Clinical Pharmacology, Ankara University School of Medicine (Ankara, Turkey). The study protocol was approved by the Ethical Committee of Ankara University School of Medicine (decision date and number: June 6, 2005/73-1876). Experimental Animals The animals in the present study were divided into three main groups and 16 subgroups. A total of 160 female Wistar albino rats, weighing between 250 and 350 g, were used in the study. The animals were provided with water and standard laboratory rat chow ad libitum that was withheld 12 h prior to surgery. The body weights of the experimental animals were recorded immediately before the surgical procedure.

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Eur Surg Res 2013;50:44–55 DOI: 10.1159/000348409



Study Groups The main study groups were formed according to the material used during the retraction, whereas the subgroups were formed according to the evaluation times. During the surgical procedure, retraction was performed by placing compresses dampened with normal saline on the intestines in group 1, by placing PVC covers in group 2, and without placing either compresses or PVC covers in group 3. In subgroup 1, a biopsy sample was obtained immediately after the laparotomy (0th hour). Biopsy samples were obtained from the three main groups on the 2nd, 24th and 72nd hours as well as on the 7th and 14th days after laparotomy, and the samples were then evaluated. Each subgroup included 10 rats. Anesthesia All experimental animals were anesthetized prior to surgery with intramuscular ketamine hydrochloride (40 mg/kg; Ketalar®; Parke-Davis/Eczacıbaşı, Istanbul, Turkey) and xylazine hydrochloride (6 mg/ kg; Rompun®; Bayer, Mefar Pharmaceutical Company, Istanbul, Turkey). After shaving the abdomen of the rats, the skin was cleaned with povidone iodine and the abdomen was prepared for the aseptic surgical procedure and covered with sterile fabric. All experiments were performed under sterile conditions. Surgical Procedure During the first surgical procedure, all experimental animals underwent laparotomy through a 5-cm midline incision and the cecum was exposed and removed from the abdominal cavity. Cecal abrasion, which is one of the adhesion models, was performed using a dry surgical compress until petechial hemorrhage in the cecal serosa occurred. The ileocecal ligament was exposed and the small intestine (5 cm proximal to the cecum) was situated to mimic the position under a retractor, which applies a constant force, and placed on the right lateral abdominal wall. The retractors were removed after 2 h and the intestines were returned to the abdominal cavity. The peritoneum and abdominal wall were closed using continuous suturing (2/0 Prolene®; Ethicon/Johnson and Johnson, St-Stevens-Woluwe, Belgium), whereas the skin was closed using single sutures (4/0 Prolene®; Ethicon/Johnson and Johnson). Next, a second laparotomy was performed under anesthesia and 1-cm-thick samples of the small intestine segments were obtained 5 cm proximal to the cecum. PVC covers used during the surgical procedures were obtained by cutting pieces from sterile saline bags. During the procedures, the body temperatures of the experimental animals were maintained at 38 ° C using heat lamps until the animals fully regained consciousness. During the postoperative period, all experimental animals were housed in individual cages and evaluated daily for wound site infection. The samples obtained during the second surgical procedure were sent to the Departments of Pathology and Histology/ Embryology for microscopy evaluation. Adhesion scoring was performed in the experimental animals using three methods. Each experimental animal that underwent a biopsy was sacrificed by aortic transection. Evaluation All tissue samples were fixed with 10% buffered formalin for 12–24 h and embedded in paraffin blocks. Sections of 4- to 5-μm thickness were obtained, stained with hematoxylin and eosin, and examined by light microscopy. The pathological examinations were performed according to a previously defined method [17]. Two pathologists, who were blinded to the characteristics of the experimental animals and the study groups, simultaneously evaluated the acute inflammation parameters caused by the peritoneal damage, including vessel congestion of the visceral peritoneum and peri-intestinal adipose tissue, leukocyte migration, mesothelial cell proliferation, and collagen production with Masson trichrome staining, for identifying early fibrosis (table 1). For electron microscopy analysis, tissues were fixed by immersion in 0.2 M phosphate buffer containing 2% (w/v) paraformaldehyde and 2.5% (v/v) glutaraldehyde for 3 h at 40 ° C. The samples were then rinsed 3 times in 0.1 M phosphate buffer and postfixed with 1% osmium tetroxide in 0.1 M phosphate buffer for 1 h at room temperature. Following three irrigations with the buffer solution, the specimens were dehydrated in graded ethanol and embedded in Araldite (Huntsman Advanced Materials, Everberg, Belgium). Semithin (1-μm thickness) sections were stained with 1% toluidine blue to identify the areas of interest by electron microscopy. Ultrathin sections (60- to 80-nm thickness) were obtained from the selected areas using a Leica Ultracut R microtome (Leica Mikrosysteme GmbH, Vienna, Austria) and stained with uranyl acetate and lead citrate. The samples were examined and photographed using an LEO 906 E electron microscope (80 kV; LEO Elektronenmikroskopie GmbH, Oberkochen, Germany).

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Eur Surg Res 2013;50:44–55 DOI: 10.1159/000348409



Table 1. Scoring via light microscopy

Congestion

0: No 1: Yes

Mesothelial proliferation

0: No 1: Yes

Leukocyte migration (extravasation)

0: No 1: Mild 2: Moderate 3: Severe (clustering and neutrophilic infiltration)

Collagenization

0: No 1: Mild 2: Severe (increased chronic fibrosis)

Table 2. Evaluation of congestion

0th hour 2nd hour 24th hour 72nd hour 7th day 14th day

Surgical compress median (min–max)

PVC cover median (min–max)

Control median (min–max)

0.00 (0 – 1) 1.00 (1 – 1) 1.00 (1 – 1) 1.00 (1 – 1) 1.00 (0 – 1) 1.00 (1 – 1)

0.00 (0 – 1) 0.50 (0 – 1) 1.00 (1 – 1) 0.00 (0 – 1) 1.00 (0 – 1) 0.00 (0 – 1)

0.00 (0 – 1) 1.00 (0 – 1) 1.00 (1 – 1) 1.00 (0 – 1) 1.00 (0 – 1) 0.00 (0 – 1)

p1 –