Assessment of adhesion formation to intra-abdominal polypropylene mesh and polytetrafluoroethylene mesh.

BACKGROUND: The development of intra-abdominal adhesions, bowel obstruction, and enterocutaneous fistulas are potentially severe complications related to the intraperitoneal placement of prosthetic biomaterials. The purpose of this study was to determine the natural history of adhesion formation to polypropylene mesh and two types of polytetrafluoroethylene (ePTFE) mesh when placed intraperitoneally in a rabbit model that simulates laparoscopic ventral hernia repair. MATERIALS AND METHODS: Thirty New Zealand white rabbits were used for this study. A 10-cm midline incision was performed for intra-abdominal access and a 2 cm x 2 cm piece of mesh (n = 60) was sewn to an intact peritoneum on each side of the midline. Two types of ePTFE mesh (Dual Mesh and modified Dual Mesh, W.L. Gore & Assoc., Flagstaff, AZ) and polypropylene mesh were compared. The rate of adhesion formation was evaluated by direct visualization using microlaparoscopy (2-mm endoscope/trocar) at 7 days, 3 weeks, 9 weeks, and 16 weeks after mesh implantation. Adhesions to the prosthetic mesh were scored for extent (%) using the Modified Diamond Scale (0 = 0%, 1 50%). At necropsy the mesh was excised en bloc with the anterior abdominal wall for histological evaluation of mesothelial layer growth. RESULTS: The mean adhesion score for the polypropylene mesh was significantly greater (P < 0.05) than Dual Mesh at 9 weeks and 16 weeks and modified Dual Mesh at 7 days, 9 weeks, and 16 weeks. Fifty-five percent (n = 11) of the polypropylene mesh had adhesions to small intestine or omentum at necropsy compared to 30% (n = 6) of the Dual Mesh and 20% (n = 4) of the modified Dual Mesh. There was a significantly greater percentage (P < 0.003) of ePTFE mesh mesothelialized at explant (modified Dual Mesh 44.2%; Dual Mesh 55.8%) compared to the polypropylene mesh (12.9%). CONCLUSIONS: Serial microlaparoscopic evaluation of intraperitoneally implanted polypropylene mesh and ePTFE mesh in a rabbit model revealed a progression of adhesions to polypropylene mesh over a 16 week period. The pore size of mesh is critical in the development and maintenance of abdominal adhesions and tissue ingrowth. The macroporous polypropylene mesh promoted adhesion formation, while the microporous nature of the visceral side of the ePTFE served as a barrier to adhesions.

Comparison of adhesion formation to intra-abdominal mesh after laparoscopic adhesiolysis in the New Zealand White rabbit.

The purpose of this study was to investigate the effects of early adhesiolysis on long-term adhesion formation after the intraperitoneal implantation of polypropylene (PP) mesh and expanded polytetrafluoroethylene (ePTFE) mesh in a rabbit model. Through a small midline laparotomy a 2 x 2-cm piece of mesh (n = 80) was sewn to an intact peritoneum on each side of a midline incision in 40 New Zealand White rabbits. Two types of ePTFE mesh [Dual Mesh (Dual) and modified Dual Mesh (C-Type), W.L. Gore and Associates, Flagstaff, AZ] and PP mesh (Marlex, C.R. Bard, Murray Hill, NJ) were compared. In 10 rabbits (n = 20) a laparoscopic adhesiolysis (LapA) was performed at one week. Mesh adhesions were scored using a modified Diamond scale (0, 0%; 1, 1-25%; 2, 26-50%; and 3, > 50%) at 1, 3, 9, and 16 weeks by serial microlaparoscopic (2 mm) examinations. After recording the final adhesion score at 16 weeks the prosthetic biomaterials were excised en bloc with the anterior abdominal wall for histologic evaluation of mesothelial layer growth (%) on the visceral surface of the mesh. Statistical differences (P value < 0.05) were measured by chi-square and Wilcoxon signed rank tests. There were no statistical differences in mean adhesion scores at adhesiolysis at 7 days. The mean adhesion scores in the groups undergoing laparoscopic adhesiolysis was statistically less (P < 0.05) for PP and both ePTFE meshes at 3-, 9-, and 16-week intervals compared with those not undergoing adhesiolysis. The percentage of mesothelialization on the visceral surface of the mesh was not statistically different between the adhesiolysis and control groups for any of the prosthetic biomaterials. Laparoscopic adhesiolysis at one week minimizes subsequent adhesion formation to PP and ePTFE mesh over a 4-month follow-up. Adhesion formation within the first 7 days after mesh implantation appears to determine the long-term adhesion score. Eliminating adhesions to mesh by mechanical or other means during this critical time may control adhesions to the mesh and subsequent mesh-related complications.

Temporary vena cava filter placement for pulmonary embolism.

Current clinical trials are under way to determine the safety and efficacy of temporary inferior vena cava filters for use in patients who need but have contraindications to anticoagulation medications for a short time (<10 days). To date, no data on these types of filters have been published. The authors describe a 20-year-old male trauma patient in whom a pulmonary embolism developed early in his hospital course and who was appropriately placed on anticoagulation therapy. Surgical intervention, however, was necessary to repair complex facial fractures sustained in a motorcycle collision. A filtering infusion catheter was placed until anticoagulation therapy could be resumed. The patient tolerated the surgery without further embolism and has recovered without difficulty.

Laparoscopic splenectomy for massive splenomegaly.

BACKGROUND: Laparoscopic splenectomy (LS) is the preferred operative approach for diseases involving normal-sized spleens. Our experience with laparoscopic splenectomy in the setting of massive splenomegaly is presented. METHODS: A prospective review of patients undergoing LS for massive splenomegaly was conducted. Massive splenomegaly (MS) in adults was defined as a craniocaudal length >or=17 cm or a morcellated weight >or=600 g. In children, spleens measuring fourfold larger than normal for age were considered massive. RESULTS: Forty-nine patients with MS were treated with LS. The most common primary diagnoses were lymphoma and leukemia. Mean splenic length was 20 cm (15 to 27 cm), with weights ranging from 600 to 4,750 g. Twelve patients with supermassive splenomegaly (length >22 cm) required a hand-assisted laparoscopic approach. There were no conversions to open surgery. Mean operating time was 171 minutes (90 to 369). Mean blood loss was 114 cc (<30 to 600 cc). Average length of stay was 2.3 days (1 to 16). Minor postoperative complications occurred in 3 patients. CONCLUSIONS: Laparoscopic splenectomy in the setting of splenomegaly is safe and appears to minimize perioperative morbidity. In patients with supermassive splenomegaly, a hand-assisted laparoscopic approach may be required.

Hand-Assisted Laparoscopic Splenectomy.

The success of laparoscopic cholecystectomy has resulted in the broad application of minimally invasive techniques in many surgery specialties. The theoretical advantages of laparoscopy over conventional open operations, including less postoperative pain, faster overall recovery, and better cosmetic results have been achieved leading to its acceptance by surgeons and the public alike. Numerous abdominal procedures have been adapted to minimally invasive approaches including bowel resection, inguinal and ventral hernia repair, anti-reflux techniques, and solid organ removal such as splenectomy.