Intraabdominal adhesion formation after preperitoneal dissection in the murine model

Mesh Fixation Devices and Formation of Intraperitoneal Adhesions

PURPOSE

To investigate the effect of mesh fixation devices on the formation of intra-abdominal adhesions.

MATERIALS AND METHODS

Fourteen New Zealand rabbits were used. In seven animals, nickel-titanium (nitinol) anchors (group 1) and titanium tacks (group 2) were applied by laparoscopy on the right and left sides of the abdomen, respectively. In the remaining seven rabbits, the same devices were applied on prosthetic meshes (groups 3 and 4, respectively). On day 30, the rabbits were sacrificed and macroscopic adhesion scoring was performed. All the specimens were assessed by scanning electron microscopy (SEM).

RESULTS

All parameters of adhesion except extension were significantly higher in group 4 than group 3 (P < 0.05). Comparisons of group 1 vs. group 2 were not statistically significant (P > 0.05). All the comparisons between a nonmesh group and a mesh group resulted in significant differences. SEM results revealed that the mesothelial cell layer and connective tissue intensively covered the tacks in group 2 whereas no similar findings were observed in group 1. Comparable appearances were encountered in groups 3 and 4.

CONCLUSION

The nitinol anchor is associated with an acceptable level of adhesion formation and its intraperitoneal use can be considered safe in this regard.

Intraabdominal adhesion formation of polypropylene mesh Influence of coverage of omentum and polyglactin

BACKGROUND

Adhesions after intraabdominal surgical procedures are related to high morbidity and mortality. Biomaterials, particularly those made of polypropylene, in the intraabdominal position have to be considered as pathophysiological cofactor in a multifactorial process of adhesion formation. To investigate the adhesive potential induced by the biomaterial, an animal model was performed. In addition, the influence of coverage by omentum or a polyglactin barrier was investigated.

METHODS

In, 18 Chinchilla rabbits the biomaterial was placed laparoscopically using the intraperitoneal onlay mesh technique. Using this model, a polypropylene-polyglactin mesh compound (PPMC) was used with three different implantation techniques: group 1, PPMC implantation without coverage (PPMC): group 2, PPMC implantation with additional omentum coverage (PPMC-O): and group 3, PPMC implantation with coverage of an absorbable polyglactin mesh (PPMC-V). The degree of adhesion formation was measured 90 days after implantation by computer-assisted planimetry. Morphometric examination followed the explantation analyzing the amount of foreign body response.

RESULTS

We found a significant reduction of adhesion formation for the PPMC and PPMC-O groups compared to the PPMC-V group, in which dense adhesions were found. Morphometric investigations of the perifilamental granulomas of the pure (PPMC) group revealed a typical foreign body reaction with a mild to moderate fibrosis around all mesh fibers. However, tissue specimens of the PPMC-O and PPMC-V groups indicated a similar inflammatory reaction but significantly increased connective tissue formation around the polymer fibers compared to the pure PPMC group.

CONCLUSION

The intraabdominal placement of a pure PPMC shows a neoperitonealization and perifilamental collagenous ingrowth with almost no adhesions. Coverage with omentum (PPMC-O) or polyglactin mesh (PPMC-V) resulted in a significant increase in inflammation and perifilamentary connective tissue formation.

Combined therapy of allantoin, metronidazole, dexamethasone on the prevention of intra-abdominal adhesion in dogs and its quantitative analysis

AIM: To observe the preventive effects of combined therapy of AMD (allantoin, metronidazolem and dexamethasone in combination) on intra-abdominal adhesion in dogs.

METHODS: 20 dogs of both sexes were used in this study. After laparotomy under anesthesia, 2 cm section of cecal end was clamped and ligated, then 1 cm cecum section was cut and another 1 cm was kept. The cecum stump was closed with purse-string suture. Both parietal and visceral peritonea were stripped for an area of about 3 × 4 cm². Before the skin closure, the animals were divided into two groups randomly. The abdominal cavities in Group AMD (n = 10) were rinsed by 200 mL of AMD solution, and with 50 mL left, whereas the control (n = 10) received the equal volume of normal saline. After 7 d, the degree of intra-abdominal adhesions was evaluated by using the score method of ultrasonography and traditional dissection.

RESULTS: Compared with the control, both the ultrasonography and traditional dissection scores in Group AMD were significantly decreased that marked as 2.0 ± 1.25 vs 3.3 ± 0.82 and 1.91 ± 0.83 vs 3.3 ± 0.82 respectively (P < 0.01).

CONCLUSION: The combined therapy of AMD is an effective way to prevent intra-abdominal adhesion, and ultrasonography is an useful tool to diagnose intra-abdominal adhesion.

The influence of intraoperative complications on adhesion formation during laparoscopic and conventional cholecystectomy in an animal model

BACKGROUND

The aim of this study was to evaluate the extent of postoperative adhesion formation after laparoscopic and open cholecystectomy.

MATERIALS AND METHODS

Qualified surgeons performed 60 experimental laparoscopic cholecystectomies (LC) in dogs with the aim to acquire the laparoscopic technique. To assess the relation between the complications during the operation (bleeding, laceration of the liver bed, or gallbladder perforation) and the formation of adhesions, surviving animals were divided into four groups according to the type of complication occurred. Assessment of the results was made by second-look laparoscopy 4 weeks after LC using the adhesion index (AI; score range, 0-4). The animals then were killed so the extent of adhesion formation could be measured. As a control, open cholecystectomy was performed in 15 dogs without intraoperative complications. The Mann-Whitney rank-sum test and Dunn's method were used for statistical analysis.

RESULTS

No adhesion formation or intraoperative complications were registered in the laparoscopic group I. In all the cases wherein bleeding or laceration of the liver bed occurred and was managed with electrocoagulation, adhesions formed. Adhesion formation in these groups was significantly higher than in "ideal LC" or cases of gallbladder perforation alone (p < 0.01). All the animals in the control group developed significantly more adhesions than those in the experimental group (p < 0.05).

CONCLUSIONS

It seems that LC has a lower rate of adhesion formation than the conventional open technique. Complications such as bleeding or laceration of the liver bed during LC can enhance adhesion formation. No adhesion formation can be mentioned in relation to gallbladder perforation during LC.

Mini-laparoscopic splenectomy

BACKGROUND AND PURPOSE

Since the introduction of mini-laparoscopic instruments (2- to 3-mm diameter), their utility and safety have been questioned. Their application in cholecystectomy has recently been documented. This study determined the adequacy and safety of these minimally invasive instruments in laparoscopic splenectomy.

METHODS

Retrospective review of all 16 mini-laparoscopic splenectomies performed by the authors was carried out. Diagnoses included immune thrombocytopenia (5), spherocytosis (6), and beta-thalassemia, sickle-cell disease, splenic mass, cyst, and splenomegaly in 1 case each. The average age of the patients was 20.1 years (range 4-70 years); seven patients were adults. Ten of the patients were female. The patients' body mass index ranged from 17 to 25 kg/m2. Splenomegaly (at least two times normal size: 100-200 g for children, 400-600 g for adults) was present in each case. A three-trocar technique was used in 15 patients, and a fourth trocar was required in only one case.

RESULTS

The average operative time and blood loss were 114 minutes (range 60-195 minutes) and 44 mL (range 10-150 mL), respectively. There were no intraoperative complications, and no patient required transfusion. Conversion to standard laparoscopy or laparotomy did not occur. The mean hospital stay was 1.4 days (range 1-2 days). With an average 20-month follow-up, no wound, septic, or other complications have been identified. All patients or their families (in the case of children) graded the cosmetic outcome as excellent.

CONCLUSION

The use of mini-laparoscopic instruments for splenectomy is safe and effective in children and adults with a normal body mass index, even in the case of splenomegaly. Operative times are reasonable, and hospital stays are brief. The postoperative cosmetic appearance is excellent.