Noxythiolin (Noxyflex), aprotinin (Trasylol) and peritoneal adhesion formation: an experimental study in the rat

Prevention of adhesions by sodium chromoglycate, dexamethasone, saline and aprotinin after pelvic surgery

BACKGROUND

The purpose of the present paper was to assess the efficacy of saline, sodium chromoglycate, dexamethasone and aprotinin, in single or in combined use in reducing postoperative pelvic adhesion formation in a rabbit model.

METHODS

A standard lesion was performed to induce adhesion formation. Forty-five rabbits were divided into nine study groups. Group 1 was the non-treatment group. In group 2, 3 cm(3) of the rabbits' own serum was instilled i.p. In group 3, 5 mg/kg sodium chromoglycate and 3 cm(3) of the rabbits' own serum were administered i.p. The group 4 rabbits were instilled with 5 mg/kg sodium chromoglycate, 3 cm(3) rabbits' own serum and 1 mg/kg dexamethasone i.p. The group 5 rabbits were injected with 5000 units aprotinin i.m. 2 h before operation and 5 mg/kg sodium chromoglycate, 3 cm(3) of rabbit serum, 1 mg dexamethasone and 5000 units aprotinin instilled i.p. In group 6, 3 cm(3) saline was instilled i.p. Groups 7, 8 and 9 were a repeat of groups 4, 5 and 6 with the exception of replacement of the rabbit serum by 3 cm(3) saline. Animals were evaluated for adhesions 10 days after operation.

RESULTS

Macroscopic adhesion scores of all the groups (2-9) were significantly less than scores of the control group (group 1). The macroscopic adhesion scores of group 9 and group 8 were significantly less compared to that of group 7.

CONCLUSION

Intraperitoneal instillation of saline and sodium chromoglycate decreased pelvic adhesion formation significantly in a rabbit model. Addition of aprotinin and dexamethasone to these agents gave a further advantage in decreasing pelvic adhesion formation.

Plasminogen activator/plasminogen activator inhibitor-1 and cytokine modulation by the PROACT System

OBJECTIVE

To examine the effects of the PROACT treatment on the fibrinolytic system and inflammatory cytokines in human peritoneum.

DESIGN

Controlled clinical study.

SETTING

University hospital.

PATIENT(S)

Nine subjects undergoing laparotomy had peritoneal samples taken at the incision.

INTERVENTION(S)

The PROACT applicator was inserted through the peritoneal incision, and treatment of peritoneum was performed twice. A peritoneal sample was taken from one treated area. At closure, the second treated sample and an additional control sample were taken. All four samples were snap frozen in liquid nitrogen. Samples were homogenized and protein content extracted.

MAIN OUTCOME MEASURE(S)

Concentrations of total and active transforming growth factor-beta 1 (TGF-beta1), tumor necrosis factor-alpha (TNF-alpha), tissue-type plasminogen activator (t-PA), urokinase plasminogen activator (uPA), and plasminogen activator inhibitor 1 (PAI-1) were obtained.

RESULT(S)

Total TGF-beta1 at opening was 30% less in treated samples. At closure, active TGF-beta1 increased significantly (163%) in control samples and not in treated samples. Tumor necrosis factor alpha was detectable only in control samples at closure. During surgery, tPA levels showed a marked decrease in control samples vs. a small increase in treated samples. Levels of uPA increased significantly only in the control samples. In control samples, tPA/PAI-1 ratio was two thirds of treated sample ratio.

CONCLUSION(S)

Heating of the peritoneum with the PROACT System modulates the biologic tissue response to induce effects that would be consistent with inhibition of postoperative adhesion development.

An experimental study of the effect of aprotinin on intestinal adhesion formation

BACKGROUND

Depression of fibrinolysis is known to be a major mechanism for postoperative adhesion formation. Because aprotinin inhibits fibrinolysis it may lead to an increase in adhesion formation whereas its anti-inflammatory effects may lead to a decrease in adhesion formation. Our aim is to clarify conflicting results in previous literature.

METHODS

Basal levels of intestinal hydroxyproline (OHP) content and local fibrinolytic activity (LFA) were determined using naive groups. In the experiment groups, adhesions were created by scraping and creating a transient ischemia of a segment of terminal ileum. Group I and II rats were injected subcutaneous (s.c.) normal saline (NS) for 3 days and single dose intraperitoneal (i.p.) NS, respectively. Group III and IV rats were injected s.c. aprotinin for 3 days and single dose i.p. aprotinin, respectively. Group V rats were injected intramuscular methylprednisolone (MP) for 3 days. LFA and OHP levels were determined on the second and fifth postoperative days. The severity of adhesion formation was graded on the fifth day.

RESULTS

Aprotinin decreased both the severity of adhesions and OHP levels whereas MP decreased only the severity of adhesions. There was an early depression of LFA at the second day in both NS and MP groups increasing to basal levels at the fifth day. OHP levels showed significant correlation with adhesion severity.

CONCLUSION

Results showed that aprotinin decreased intra-abdominal adhesion formation probably by preventing early depression of LFA.

Adhesion formation of the parietal and visceral peritoneum: an explanation for the controversy on the use of autologous and alloplastic barriers?

OBJECTIVE

To compare formation of adhesions after injury to both parietal and visceral peritoneum and to determine the benefit of autologous transplants and alloplastic barriers in adhesion prevention.

DESIGN

Experimental prospective animal study and prospective randomized clinical study.

SETTING

An academic research environment.

PATIENT(S)

Forty women undergoing laparoscopy for endometriosis treatment.

INTERVENTION(S)

In 60 rats, either the visceral or parietal peritoneum was injured and covered with autologous peritoneal transplants in half of the animals. The formation of adhesions was assessed 21 days postoperatively. In women, adhesions were evaluated 3 months after surgery with or without placement of alloplastic barriers on visceral lesions.

MAIN OUTCOME MEASURE(S)

Adhesions evaluated according to a scoring system.

RESULT(S)

Adhesions after injury of the visceral peritoneum in rats were significantly more severe than those from the parietal peritoneum. Autologous peritoneal transplants led to fewer adhesions especially after serosal injuries. Female volunteers treated with alloplastic barrier material showed less severe adhesions than the control group.

CONCLUSION(S)

The present data indicate that the potential to form adhesions is significantly higher in visceral than in parietal peritoneal lesions. The development of adhesions after injury to the visceral peritoneum could be reduced by a synthetic barrier material.

The results of laparoscopic adhesiolysis for intractable urinary frequency

PURPOSE

We evaluated urinary frequency related to pelvic adhesions around the bladder serosa and the result of laparoscopic adhesiolysis on intractable urinary frequency caused by adhesions that did not respond to conservative treatment.

MATERIALS AND METHODS

Laparoscopic adhesiolysis was performed for the diagnosis and treatment of 10 referred patients with a history of pelvic surgery in whom conservative treatment had failed. Urinary symptoms and signs, a urinary diary and cystometry were followed before and after surgery.

RESULTS

In all cases there were various degrees of pelvic adhesion, mainly around the bladder. Frequency and urgency were improved in 9 of 10 patients. Urinary diary and cystometry parameters showed improvement at followup.

CONCLUSIONS

Adhesions involving the bladder wall may restrict bladder distension in most of these patients. Laparoscopic adhesiolysis is beneficial in the diagnosis and treatment of this subgroup of patients.

Incidence of adhesions following thermal tissue damage

Coagulation and vaporization of tissue are techniques applied in pelviscopic surgery in order to achieve hemostasis as well as cut and destroy endometriotic implants. An animal experimental study was devised to show if there is a difference in the incidence of adhesions after vaporization of equal-sized areas of the anterior abdominal wall of the rat compared to coagulation of equal-sized areas. A similar depth of the lesions was achieved by repeating the vaporization procedure. The rate of adhesions was significantly lower (P less than 0.001, Chi2-test) post-coagulation, using a biopolar high frequency current or post-endocoagulation than post-vaporization. The surface vaporization of tissue, for example endometriotic implants, as produced by laser is to be viewed critically as regards the higher incidence of adhesions after vaporization compared with coagulation.

Intraperitoneal application of fibrinogen gluing in the rat for adhesions prophylaxis

The suitability of fibrinogen gluing for prophylaxis of intraperitoneal adhesions was investigated experimentally. Small bowel slings, traumatized previously, were covered by a layer of fibrinogen 2-3 mm thick to see whether formation of adhesions could be prevented. In the experiments 50 rats of both sexes were observed over 21 days. Following mechanical traumatization of the terminal ileum the visceral peritoneum was coated with fibrinogen, whereas animals of the control group did not receive fibrinogen coating. Macroscopic and microscopic findings after 1, 3, 7, 14 and 21 days yielded the following results: 1. Fibrinogen dissolution and resorption occurred for 3-14 days following operation. 2. On autopsy, all animals of the control group showed massive, extended adhesions; two of the controls died on the 6th postoperative day from peritonitis. 3. None of the treated animals exhibited extended adhesions. 4. Histological examinations revealed regeneration of the injured serosa and healing of the bowel wall below the fibrinogen coating. 5. Fibrinogen applied to intact peritoneal serosa (without injury) is entirely resorbed without formation of adhesions.

Problems of fibrin adhesion of the nerves

Although the fibrin adhesion enjoys increasing success in many areas of surgery, it has not, however, become fully established in nerve anastomosis. It was in this area particularly that significant advantages were expected. As the fibrin clot dissolved prematurely, however, and dehiscences ensued, antifibrinolytic substances had to be added to the adhesive. Fibroses occurred frequently as a result, which to date encumber nerve adhesive. We examined various factors of the adhesive system for their fibrosis-inducing effect. We were able to establish that no additional fibrosis-promoting effect emanated from aprotinin and the fibrin clot as a supply barrier, whereas thrombin, Factor XIII and fibronectin possess a fibrosis-promoting effect.

A model for sidewall adhesions in the rabbit: reduction by an absorbable barrier

Despite use of surgical adjuvants, pelvic adhesions frequently develop following infertility surgery. Recently a resorbable biocompatible material, TC 7, has been designed to be used as a barrier to reduce adhesion formation. Reproducibly severe sidewall adhesions were only able to be created in one of six models tested. The model consisted of the following steps: excision of a full thickness 2 x 2-cm musculoperitoneal tissue mass, scraping of an adjacent 2-cm length of uterine horn, tamponading of all bleeding, and suturing (6-0 Vicryl) of normal tube and sidewall so as to directly approximate the traumatized tissues. Studies were conducted in 13 rabbits after creation of the bilateral sidewall and horn lesions, each serving as its own control. Choice of control and TC 7 sides was determined randomly. Adhesion formation was examined 2 weeks postoperatively. No residual material was noted at that time. Adhesion scores were the composite total of extent (0-4), type (0-4), and tenacity (0-3) of sidewall adhesions, and were significantly reduced on the TC 7 side as compared with the control side (mean 6.8 +/- 0.4 vs 9.0 +/- 0.3, median 6 vs 9, sign test P = 0.0032). No complications of use of the barrier were noted. It is concluded that use of TC 7, a resorbable biocompatible barrier, was able to significantly reduce postoperative adhesion formation on the rabbit sidewall.

Pathogenesis of adhesion formation/reformation: application to reproductive pelvic surgery

Pelvic adhesions are a major contributing factor to infertility in women with tubal peritoneal disease. Surgical treatment of such adhesions often does not resolve their presence. Such postoperative adhesion formation occurs despite the use of microsurgical techniques in a wide variety of surgical adjuvants. The process of adhesion formation represents a variation of the normal healing process of the peritoneum. However, rather than normal mesothelial healing, the fibrinous mass resulting from the peritoneal defect is infiltrated by fibroblasts with subsequent adhesion formation. A description of the pathophysiology of this process is described. The current understanding of the pathologic/pathophysiologic interaction of the surgical adjuvants with this process is described.

Effect of aprotinin on fibrinopurulent peritonitis in rats

The effect of aprotinin on the clinical and pathologic course of experimentally induced peritonitis in the rat was studied. Peritonitis was induced in 40 rats by creating a closed ileal loop 4 cm long 5 cm from the ileocecal valve. The rats were divided into two groups of 20 rats each. Group 1 served as a control group, whereas each animal in Group 2 received a bolus dose of aprotinin (10 ml) intraperitoneally immediately after closing the laparotomy. In the aprotinin-treated group, survival was drastically increased (p less than 0.01) and formation of adhesions and abscesses was considerably reduced. The results of peritoneal cultures showed a decreased incidence of Escherichia coli and Clostridia in the aprotinin-treated group. We conclude that the administration of aprotinin significantly prolongs the survival time of animals with peritonitis and reduces the development of adhesions and abscesses in the peritoneal cavity. This beneficial effect can be attributed to decreased fibrinogen deposits within the peritoneal cavity and the stabilization of the organism after bacterial shock. Thus, bacteria were more susceptible to cellular and noncellular clearing mechanisms.

The effect of intravenous aprotinin (Trasylol) on intraperitoneal adhesion formation in the rat

A randomized controlled trial to assess the effect of intravenous Trasylol on postoperative intraperitoneal adhesion formation has been performed in rats. Before undergoing a standard left colonic resection, animals received i.v. Trasylol 10 000 KIU. This dose was repeated 8-hourly for 3 days postoperatively. Control animals received saline placebo. The mean percentage circumference of the anastomosis covered with adhesions in the Trasylol group animals was 20.86 +/- 6.08 compared with 45.24 +/- 5.97 in the control group (P less than 0.01). Significantly more animals treated with Trasylol were completely free of adhesions than those receiving saline. Bursting pressures did not differ between the two groups. Intravenous Trasylol clearly inhibits intraperitoneal adhesion formation in this model.