Experimental animal model for readhesion formation study

The problem of postoperative adhesions remains unsolved. The formation of readhesions after tubal reconstructive surgery reduces the success rate. We have developed a modified uterine horn model in the rat to study the influence of peritoneal transplants on readhesion formation. A total of 58 rats were operated. In 25 animals (group III) the uterine horn was scratched on both sides and then sutured together. During relaparotomy 14 days later the tight connection between both sides was cut. The resulting defect was covered by a peritoneal transplant on one side (group IIIb) and was left open on the control side (group IIIa). After 14 days the presence or absence of adhesions was explored. There was a significant difference (p < .001) between the covered (28%) and uncovered (84%) peritoneal defects with respect to incidence of adhesions. To compare the different characteristics of visceral and parietal peritoneum, a pelvic sidewall defect was induced in 33 animals. There was no significant difference between covering the defect by a peritoneal transplant (group II; 42.9%) and the control side (group I; 33.3%). These data suggest that defects on visceral peritoneum should be closed to prevent adhesion formation. The incidence of adhesions after injury of parietal peritoneum seems to be much lower and of less clinical significance.

Interim report in humans of a previously described technique in an animal model: closure of bladder exstrophy with rectus abdominis muscle flap-II

The results of a new bladder closure and augmentation technique in children born with bladder exstrophy are reported. The technique was performed in 6 children, including 4 who had, in addition to a small, inelastic, noncompliant bladder, squamous epithelial metaplasia and polypoid transformation. In the remaining 2 patients this technique was used after failed primary closures. A full thickness left rectus abdominis island flap containing skin, fascia, muscle and peritoneal layers is prepared with an intact neurovascular pedicle from the inferior epigastric artery. This flap is rotated to cover the bladder defect and aid in augmentation. The inner layer formed by peritoneum is sutured to the edges of the bladder defect. Postoperative endoscopic and histopathological investigations revealed the inner peritoneal layer of the flap to be completely covered by transitional bladder epithelium. No major surgical complications occurred in these 6 cases. Considering the advantages of the technique from this limited experience, evidence suggests that there is no need for a major gastrointestinal operation for bladder augmentation, since an acceptable bladder capacity was available. There was no mucus production from the inner layer of the flap, and metabolic and electrolyte disturbances were reduced.

Efficacy of autologous peritoneum as a biological membrane in cardiac surgery

The risks for reoperative cardiac surgery are related to the presence of intrapericardial adhesions and the possibility of catastrophic injury at repeat sternotomy. In an attempt to develop an improved pericardial substitute and vascular patch, the feasibility of using autologous peritoneum was evaluated. Twelve mongrel dogs were studied. A peritoneal-rectus fascia patch, including the overlying posterior rectus sheath was harvested, via a lateral abdominal incision, and stored in normal saline. In the first group of six animals, a pulmonary artery (PA) window was created and then closed with the peritoneal-rectus fascia patch. In the second group a secundum atrial septal defect was created and then closed with the peritoneal patch on cardiopulmonary bypass (CPB). In each animal, the peritoneal-rectus fascia patch was used to permit pericardial closure. Autopsies performed at 90 days postoperatively revealed only slight intrapericardial adhesion formation and a mild epicardial reaction. Histological examination of the peritoneal-rectus fascia patches revealed intact morphology with active fibroblasts and smooth muscle cells. Proline 14C absorption and autoradiography detected viable cells in the implanted patches. These findings suggest that a peritoneal-rectus fascia allograft could be useful as a biological membrane, and as a satisfactory pericardial substitute in the development of strategies to reduce the risk for reoperative cardiac surgery.

Experimental rectus abdominis myocutaneous and rectus abdominis myoperitoneal flaps as urinary bladder wall substitutes in miniature swine

An experiment was performed in Yucatan miniature swine to determine the feasibility and characteristics of musculocutaneous or musculoperitoneal flaps as urinary bladder wall substitutes. In five swine, a single-pedicle skin island flap (rectus abdominis myocutaneous, RAM/C) was sutured into the bladder. In five other swine the flap was a peritoneum island (rectus abdominis myoperitoneal, RAM/P). Three swine were sham-operated controls. The patches were in place for 20 weeks, remaining viable and elastic. Inflammation, maceration, and infection were absent. Skin patch histology was unchanged. The peritoneal patches became resurfaced with uroepithelium. The sham bladder volume (ml/kg body weight) did not differ significantly from RAM/P bladder volume (p = 0.54). RAM/C bladders were slightly smaller than shams (p = 0.11) and significantly smaller than RAM/P bladders (p = 0.03). Substitution of the bladder wall with RAM patch flaps is feasible. This is an important preliminary step toward our goal of nonenteral urinary bladder wall substitution.

Pedicle grafts of peritoneum and transversalis muscle for the repair of large defects in the duodenal wall

OBJECTIVE

To find out if pedicle grafts of peritoneum and transversalis muscle could be used to repair large defects in the wall of the duodenum.

DESIGN

Experimental study.

MATERIAL

18 healthy mongrel dogs.

INTERVENTIONS

Defects were created in the second part of duodenum and repaired with pedicle grafts of peritoneum and transversalis muscle from the anterior wall of the right side of the abdomen.

MAIN OUTCOME MEASURES

Postoperative complications, appearances on upper gastrointestinal radiography two and four months after operation, and histological examination of necropsy specimens.

RESULTS

There were no postoperative deaths or complications. Radiographs of the duodenum showed no abnormalities and in particular no signs of obstruction. Animals were killed at intervals from one week to eight months after operation, and the only abnormality was 20-30% stenosis found in five dogs killed within two months of operation, which did not affect gastric emptying. Histological examination showed that by four months after operation the patch was completely covered by neomucosa that was similar to normal duodenal mucosa. By six months the site of the defect was well healed and the histological appearance was the same as at four months.

CONCLUSION

Pedicle grafts of peritoneum and transversalis muscle may be useful in the treatment of patients with large defects in the wall of the duodenum.

Evaluation of peritoneal tube grafts in the inferior vena cava of the pig

A tube graft 2.5 or 5 cm long, was constructed from the peritoneum of the anterior abdominal wall of 12 pigs. It was anastomosed end-to-end as an interposition graft in the infrarenal vena cava. The observation period was 4 months. Three of the six short grafts were venographically patent at 2 weeks, while all the long grafts were occluded. After 4 months two short grafts had recanalized, giving a patency rate of five out of six short grafts. No long grafts recanalized. In three of the patent specimens no clear tissue changes were found with light microscopy, while in the others changes of inflammation and fibrosis were noted. Scanning electron microscopy revealed good 'endothelialization' in two specimens, and partial 'endothelialization' in the others. No dilatation or severe stenosis of the patent grafts was seen. The occluded grafts remained only as a fibrous strand with sutures.

[Use of xenoperitoneum saturated with drugs in the treatment of suppurative wounds]

A method of preservation of xenoperitoneum of the cattle is described as well as the technique of its saturation with a complex of drugs selected with the reference to susceptibility of the flora, phase and character of the purulent wound. Clinical data are presented characterizing the course of the purulent process under conditions of the application of the proposed biological drainage, which proves the possibility to stimulate wound healing and to shorten the time of treatment of the patients.

Patch grafting the renal pelvis and ureteropelvic junction. A comparative study in pigs using lyophilized dura mater and free peritoneum

Lyophilized dura mater (Lyodura) and autogenous free peritoneum were compared in the replacement of the partially resected renal pelvis and uretero-pelvic junction (UPJ) in the pig. The Lyodura and peritoneum grafts were both progressively resorbed, and replaced by fibroblasts which formed a mature scar lined by transitional epithelium, but without smooth muscle regeneration. Lyodura was found to be superior to free peritoneum with a longer time before resorption of the graft, less intense inflammatory reaction, absence of metaplastic bone formation, less risk of urine leak and greater ease of surgical manipulation.

Morphology and fibrinolytic activity of canine autogenous mesothelium used as venous substitute

Autogenous mesothelium was used as venous substitute in ten dogs. Patches of mesothelium of three different origins were grafted into the anterior wall of the common iliac veins (CIV): peritoneum taken from and including the posterior rectus sheath (PRS), simple peritoneum (P) and mesentery (M). Animals were killed after 2, 4, 8, and 16 days and after 3 months. The segments of CIV, including the patches, were removed for study. On light microscopy, the PRS grafts showed a normal mesothelium but marked submesothelial fibrosis. The M and P grafts showed normal mesothelium and only mild fibrous thickening. On scanning electron microscopy, there was a perfect continuity of the mesothelial cells and the normal endothelium at the suture line. In the center of the graft, the cells had become elongated along the axis of blood flow. Fibrinolytic activity (FA) was measured by a standardized fibrin plate technique and quantitated in tissue activator units per gram of tissue (TAU/g). The mean FA of iliac vein specimens was 1101.7 +/- 133.3 TAU/g (mean +/- SEM). The mean FA determined before grafting for each kind of mesothelium was the following: PRS = 418.8 +/- 26.9 TAU/g; P = 873.0 +/- 107.1 TAU/g; M = 1142.3 +/- 91.4 TAU/g where only PRS showed values significantly lower than iliac vein mean FA (P less than 0.001). Postoperatively, the mesothelial FA, after an initial reduction, increased on day 4 and reached values significantly higher than the control values (1445.7 +/- 204.1 TAU/g tissue vs 853.1 +/- 62.3 TAU/g tissue; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Bridging extensive esophageal atresias by a peritoneal transplant]

A method is presented that represents a modification of Rehbein's perlon filament technique for treating extensive oesophageal atresias. This new approach enables, in case of congenital oesophageal defects exceeding three vertebral bodies in length, to eventually perform end-to-end anastomosis of the patient's oesophagus. For this purpose, the distance between the mobilised oesophageal segments that are interconnected by means of a centrally positioned perlon filament, is additionally bridged over with a peritoneal cylinder in the sense of an autotransplant. The advantages of the method are the creation of a wide preformed channel for subsequent bougineages, the protective effect exercised on the mediastinum to prevent possible inflammatory conditions, and especially the continuous traction exercised on both oesophageal pouches by the shrinking of the transplant resulting in a ring-shaped stenosis that is easy to resect and can be bypassed via end-to-end anastomosis. We treated according to this method from 1982 onwards seven children with congenital oesophageal atresias extending over the length of three to seven vertebral bodies; four of these patients now present with patent oesophageal passage.

Local excision of urothelial cancer of the upper urinary tract

In 9 of 93 patients (9.7%) with urothelial cancer of the upper tract (7 renal pelvis tumors, 3 ureteral tumors), conservative surgery was employed using a free peritoneal autotransplant for replacement of the renal pelvis in 5 kidneys. Absolute indications for conservative surgery were solitary kidneys/nonfunctioning contralateral kidneys in 4 patients and bilateral tumors in 1 patient. Local recurrences developed 1-3 years after operation in 4 of 6 kidneys (3 patients), 3 of which had grade-2 and grade-3 primary lesions. All patients were treated successfully by repeated local excision. In the presence of a normal contralateral kidney, local tumor excision was done electively in 4 patients (3 low-grade/low-stage lesions, 1 high-risk patient), none of these patients developed recurrences. Two patients died without evidence of tumor recurrence, 7 patients are free of tumor at an average follow-up of 23 months (range 5-65 months). Local excision of urothelial cancer should be considered not only for solitary kidneys, bilateral tumors and cases with renal failure, but also for low-stage/low-grade localized tumors, leaving the patient better prepared for later treatment of a possible recurrence due to the well recognized chance of a multiplicity of tumors in time and space.

A new site for islet transplantation--a peritoneal-omental pouch

A new site for islet transplantation is described. A peritoneal-omental pouch was constructed in diabetic rats by encasing the omentum in a pouch formed from a strip of parietal peritoneum obtained from the recipient. Isografts of rat islets placed in the pouch maintained normoglycemia in the recipients and removal of the pouch resulted in a rapid return to a diabetic state. This site may be applicable to the transplantation of islets in human diabetes.

[New technique of renal plication for the treatment of severe hydronephrosis]

We present the case of an eleven-year old boy affected of giant hydronephrosis on a unique right pelvic kidney, treated according to an original technique consisting in the use of a free peritoneal flap for the completion of a renal banding to complement Mollard's (1973) and Stewart Hamilton's (1957) nephroplasty procedures.

[Surgical prevention of peritonitis in resection of the colon for cancer]

A method of biological hermetization of the anastomosis by a peritoneal graft on the feeding pedicle is described which was used in 35 patients with carcinoma of different parts of the colon. There was no incompetent enterocolostomy in the patients following different kinds of resections of the colon. The proposed method does not make the operation longer.

Artificial vaginas: possible sources of epithelialization

Biopsy specimens from surgically created peritoneium-lined vaginas in 23 patients with complete vaginal agenesis showed squamous metaplastic epithelium lining the vaginal canal. In nine of the patients, histologic or cytologic evidence, or both, suggested that the metaplastic squamous epithelium could be derived from pre-existing glandular epithelium - sebaceous, paramesonephric (mullerian), or urogenital sinus. The histologic and cytologic features in six patients with paramesonephric-like gland elements in the mucosa and submucosa of the neovagina were similar to the features seen in milder forms of vaginal adenosis.

Comparative study of free omental, peritoneal, Dacron velour, and Marlex mesh reinforcement of large-bowel anastomosis: an experimental study

The comparative role of free omental, peritoneal, Dacron velour, and Marlex mesh grafts in reinforcement of an extremely vulnerable experimental model of large-bowel anastomosis was studied in dogs. While both the omentum and peritoneum proved not to be effective in preventing anastomotic leakage, Dacron velour did considerably lower this incidence to within reasonable limits but led to formation of low-grade lymphoma at the reinforcement site in two animals. Only Marlex mesh was found to be highly effective in sealing the suture line, and it is anticipated that, with the usual technique of anastomosis, this sealing effect will be foolproof, thereby nullifying any risk of suture-line breakdown.