Eli Pines

Synergistic effects of INTERCEED(TC7) * and heparin in reducing adhesion formation in the rabbit uterine horn model † ‡

Surgical adjuvants are commonly employed to reduce the frequency of postoperative adhesion development after reproductive pelvic surgery. The ability of indomethacin, promethazine dexamethasone, Intralipid, progesterone, and heparin to reduce adhesion formation in combination with INTERCEED(TC7) (Johnson and Johnson Medical, Inc., New Brunswick, NJ), an absorbable barrier that alone reduces adhesion formation, was examined in a rabbit uterine horn model. A significant reduction in adhesion formation was only observed with the combination of INTERCEED(TC7) plus heparin. In addition studies, heparin delivery by intraperitoneal (IP) lavage, intravenous injection, or intra-abdominal instillation failed to demonstrate efficacy. Similarly, heparin delivery with other barriers or IP instillates (carboxymethylcellulose or 32% Dextran 70) failed to reduce adhesion formation. We conclude that INTERCEED(TC7) can be efficaciously utilized as a carrier to deliver heparin to traumatized surfaces, thereby reducing adhesion formation.

Evaluation of polyethylene glycol/polylactic acid films in the prevention of adhesions in the rabbit adhesion formation and reformation sidewall models

OBJECTIVE To assess the efficacy of bioresorbable films consisting of various polyethylene glycol 6000 and polylactic acid block copolymers on the formation and reformation of adhesions in rabbit models of adhesion development between the sidewall to the adjacent cecum and bowel. The composition of the different polymers was expressed by the number of monomeric units in the block, namely, ethylene oxide (EO) and lactic acid (LA), respectively. DESIGN Studies of the efficacy of EO/LA films were conducted in rabbit sidewall adhesion formation studies in the presence and absence of blood and in rabbit adhesion reformation studies. REPEL (Life Medical Sciences, Edison, NJ), a film of EO/LA ratio 3.0 manufactured under commercial conditions, was also tested in these animal models. SETTING University-based laboratory. ANIMALS New Zealand white rabbits. INTERVENTION(S) Placement of films of various EO/LA ratios at the site of injury to the parietal peritoneum. MAIN OUTCOME MEASURE(S) Adhesion formation and reformation. RESULT(S) Films of various EO/LA ratios, Seprafilm (Genzyme, Cambridge, MA) and Interceed (Johnson and Johnson Medical, Arlington, TX) placed over an area of excised sidewall at the time of initial injury were highly efficacious in the prevention of adhesion formation. A film of EO/LA ratio 3.7, in contrast with Interceed, was also shown to maintain maximal efficacy in the reduction of adhesion formation in the presence of blood. Further, a film of EO/LA ratio 3.0 produced under commercial conditions, REPEL, was highly efficacious in reducing adhesion development in the rabbit models of adhesion and reformation. CONCLUSION(S) These studies suggest that bioresorbable EO/LA films reduced adhesion development in rabbit models of adhesion formation and reformation.

Reduction of retrosternal and pericardial adhesions with rapidly resorbable polymer films

BACKGROUND The formation of postoperative cardiac adhesions makes a repeat sternotomy time consuming and dangerous. Many attempts have been made to solve this problem by using either drugs to inhibit fibrinolytic activity or different types of pericardial substitutes. The results have not been satisfactory. METHODS The efficacy of bioresorbable film prototypes made of polyethylene glycol (EO) and polylactic acid (LA) (EO/LA = 1.5, 2.5, and 3.0) in the prevention of adhesions after cardiac operations in canine models was tested. After desiccation and abrasion of the epicardium, a transparent bioresorbable film was placed over the heart. The pericardium was closed to allow intrapericardial adhesions (n = 32) or left open and attached to the chest wall to induce retrosternal adhesions (n = 17). Postoperative recovery was similar among the groups. Retrosternal and pericardial adhesions were evaluated at necropsy 3 weeks later by assessing area, tenacity, and density of the adhesions. RESULTS In the control dogs, tenacious, dense adhesions were observed. In contrast, adhesion formation was reduced at all sites covered by the films. The bioresorbable films were efficacious in the reduction of adhesion formation between epicardium and pericardium or between epicardium and sternum after cardiac operation. The EO/LA 1.5 film most effectively prevented the early adhesions. CONCLUSIONS The bioresorbable films (EO/LA = 1.5, 2.5, and 3.0) significantly reduced adhesion formation, with EO/LA = 1.5 (Repel CV) being optimal. As the barrier was rapidly resorbed, the capsule formation induced by permanent barriers was avoided.

A new model for experimental tendon adhesions in the chicken

&NA; A minimally invasive model using a manual abrader to induce adhesions in the chickens central digit is described. The flexor synovial sheath and the profundus tendon were abraded with access through small flaps at the level of the proximal and distal phalanges of the avian long toes. The birds were divided into two groups according to the severity of the induced trauma. Group I birds received an abrasion injury and were euthanized to allow biomechanical testing 5 weeks postoperatively. Group II birds had a more severe abrasion and were euthanized similarly and tested 5 weeks after surgery. Results were compared with nonsurgical controls. Long toe function was evaluated weekly by measuring (1) the range of active flexion of each interphalangeal joint, resolved to total angular range; (2) the grasping ability on graded‐diameter perches; and (3) the flexion deficit of the long toe. Postmortem biomechanical properties of the adhesions were measured. There was a significant difference between the unoperated controls and abraded digits of both groups in all parameters (p < 0.001). There was, in addition, a marked change in most of the measured parameters between groups I and II. In group I digits the functional and biomechanical deficit was less than group II. In summary, this animal model of long‐segment abrasive injury to the tendon and sheath is a simple and reproducible method to generate adhesions and can be used for the evaluation of treatment modalities for adhesion prevention. Jaibaji M, Brody GS, Rodgers K, Espinoza T, Roda N, Maldonado S, Pines E, diZerega G. A new model for experimental tendon adhesions in the chicken. Ann Plast Surg 2000;44:205‐210