The uncut Roux-en-Y with jejunal pouch: a new reconstruction technique for total gastrectomy.

BACKGROUND: Roux Stasis Syndrome is a well-known complication after Roux-en-Y reconstruction. It has been hypothesized that reconstruction with an uncut Roux limb and jejunal pouch after total gastrectomy would preserve unidirectional intestinal myoelectrical activity, improve postoperative weight gain and nutritional parameters, and diminish Roux Stasis Syndrome in canines. METHODS: A total gastrectomy was performed, and 2 methods were used for reconstruction: Roux-en-Y esophagojejunostomy (RY) was performed on 5 canines (control), and the uncut Roux-en-Y with a jejunal pouch (URYJP) was performed on 5 other canines (experimental). The canines were monitored for 10 weeks postoperatively. Serial weight and nutritional parameters were measured. Emptying profiles and motility studies were performed in the fasting and postprandial states. RESULTS: Ten weeks after operation, the URYJP group had significantly improved nutritional parameters, including weight, total protein, albumin, hemoglobin, serum total iron binding capacity, and serum IgA, IgG, and IgM. The emptying times for both groups were similar, with an increase of disordered propagation of the jejunal pacesetter potential in the RY group. The aboral propagation occurred more frequently in the URYJP group during fasting and after feeding (98% +/- 1% vs 39% +/- 16%; P = .02, and 99% +/- 1% vs 43% +/- 18%; P = .03). The sites of luminal occlusions were intact in the URYJP group at 10 weeks. CONCLUSIONS: The combination of jejunal pouch and uncut Roux limb improved overall nutritional parameters when compared with the traditional Roux-en-Y, while preserving aboral propagation of jejunal pacesetter potentials.

Prefabricated buccal mucosa-lined flap in an animal model that could be used for vaginal reconstruction.

Congenital vaginal aplasia, gynecological tumor excision, and male-to-female sex surgery are three clinical conditions in which the plastic surgeon is involved in vaginal reconstruction. Skin-lined or skin-grafted local flaps are currently used, but for many reasons, keratinized skin is not the ideal lining for such a moist cavity because it leads to dryness, desiccation, maceration of the skin, and even hair growth in the cavity. The purpose of this study was to create a subcutaneous cavity lined with mucosa in an area with a predictable blood supply. The abdominal area supplied by the deep circumflex iliac vessels was chosen. Six minipigs were used. Strips of tongue buccal mucosa formed the lining; if additional tissue was required, it was taken from the mucosal aspect of the cheek. The mucosa was expanded by using multiple stab incisions. The mucosa was sutured onto the fascia supplied by the deep circumflex iliac vessels, and the skin incision was closed over a silicone sheet to prevent adhesion to the underlying mucosa. This was left for 1 week to allow the mucosa to take. The prefabricated fascial flap was rolled over a silicone stent and was closed longitudinally to form a cylindrical shape. The flap was placed in a subcutaneous pocket in the right inguinal area. The caudal end was left open and was sutured to the surrounding skin. The silicone stent was used to keep the cavity patent and to prevent adhesions in the early stage of the healing process. Regular digital examination was performed to assess patency and contour; endoscopy allowed assessment of mucosa viability. This method of producing a mucosa-lined flap may provide a solution to the difficult problem of vaginal reconstruction.

The effect of low-molecular-weight heparin in the survival of a rabbit congested skin flap.

Swelling and congestion of flaps are frequently seen postoperatively and can cause unexpected necrosis. According to previous reports, venous thrombosis seems to be a more frequent problem than arterial occlusion in both experimental and clinical surgery. Few satisfactory venous trauma models exist, and reports on experimental venous thrombosis are rare. The object of this study was to create a rabbit venous occlusion flap model and to evaluate the effect of low-molecular-weight heparin on this flap. Eight New Zealand rabbits were used in the pilot study, in which the ideal congested flap was investigated using a flap pedicle based on the central auricular artery with a skin pedicle 0, 1, 2, or 3 cm wide. The flap (3 x 6 cm) was designed on the central part of the left ear, and the central auricular vein and nerve, the former for venous return, were cut out at the base of the flap. The flaps with skin pedicles 0, 1, 2, or 3 cm wide showed mean necrosis length of 60.0, 9.3, 4.2, and 0.0 mm, respectively. The flaps with skin pedicles 0, 1, 2, or 3 cm wide showed mean necrosis of 100, 15.5, 7, and 0 percent, respectively. Therefore, the flap, based on a 1-cm-wide skin pedicle and the central auricular artery, was selected as an optimal congested flap model showing 15.5 percent necrosis. The congested flap was then elevated on the left ear of another 10 rabbits. Subcutaneous low-molecular-weight heparin (320 IU/kg) was administered immediately after surgery to five of the rabbits (the low-molecular-weight heparin group), and the remaining five were used as a control group. Fluorescein was injected 15 minutes after surgery to evaluate the circulatory territory of the flap, and the circulatory territory was measured 5 minutes after injection. The flaps were assessed 7 days after surgery by angiography, histology, and clinical findings. The circulatory territory was significantly greater in the low-molecular-weight heparin group (mean +/- SD, 39.2 +/- 3.0 mm) than the control group (mean +/- SD, 48.0 +/- 1.0 mm) (p < 0.001) assessed 7 days after surgery. The longest flap survival length in group A and group B ranged from 40 to 55 mm (mean +/- SD. 49.4 +/- 5.6 mm) and complete survival (mean +/- SD, 60.0 +/- 0.0 mm). The improvement in survival was statistically significant for group B compared with group A (p < 0.015). Histologic evaluation revealed moderate to severe venous congestion and inflammation in the control group, whereas there were minimal changes in the low-molecular-weight heparin group. Angiography of the flap revealed obvious venous occlusion in the periphery in the control group compared with the low-molecular-weight heparin group. The authors conclude that subcutaneous administration of low-molecular-weight heparin has a great potential to improve the survival length of a congested flap without major complications.

Easy tissue expansion of prelaminated mucosa-lined flaps for cheek reconstruction in a canine model.

In head and neck reconstruction, there is sometimes the need for a skin flap lined with mucosa. The object of this study was to determine whether small pieces of mucosa grafted onto the undersurface of a skin flap can be expanded in a reasonable time to provide the material required to reconstruct a full-thickness cheek defect as a free flap. The study consisted of two phases: prelamination and expansion of the flap, and vascularized free-tissue transfer of the flap. Six adult mongrel dogs were used. First, a 5 x 10-cm flap based on the saphenous vessels was elevated on the lower leg, and then four 1 x 2-cm pieces of mucosa harvested from the tongue were grafted onto the undersurface of the flap. A tissue expander (5 x 10 cm) was then placed under the flap, and the incision was closed primarily. The expanders were initially filled with just enough normal saline to obliterate dead space immediately after surgery. The expansion was continued twice weekly for 3 weeks until sufficient expansion was obtained. Two of six flaps were followed for an additional 6 weeks after the 3-week expansion period to observe whether additional mucosa could be obtained. After measurement of the mucosal area, each flap was transferred as free flap to reconstruct an iatrogenic cheek defect. The increase of mucosal surface area was compared with the original graft, and differences were analyzed using the paired t test. All flaps were successfully expanded without any complications. Histologic evaluation revealed that grafted mucosa took well without evidence of graft necrosis, and the intergraft area was covered with histiocytes. Angiography revealed well-defined vascular structures covering the entire area of the flap. The new mucosal area (23.5 +/- 2.4 cm2) was significantly larger than the original mucosal graft (8.7 +/- 0.9 cm2) (p < 0.001). The net increase of the mucosal area was 172.9 +/- 32.4 percent. The increase of mucosal area in two flaps, following a 6-week consolidation period after 3 weeks of expansion, was only slightly greater (25.9 +/- 1.3 cm2) than those without the consolidation period (22.3 +/- 1.8 cm2). This increase of the mucosal area appears to be related to the amount of expansion, and not to the length of the consolidation period. The flaps were successfully transferred as free flaps to reconstruct the full-thickness cheek defects without major complications. Although a staged operation to allow flaps to mature is needed, the present procedure has the advantages of providing a mucosa-lined flap and allowing primary closure of the donor site. The authors conclude that expansion of this flap has great potential in reconstructive surgery.

Topical gentamicin does not provide any additional anastomotic strength when combined with fibrin glue.

BACKGROUND: We evaluated the effect of a combination of fibrin sealant and topical gentamicin on a colonic anastomosis in a rat model. METHODS: Partial anastomosis in the transverse colon was performed in 70 male Sprague-Dawley rats aged 6 to 10 weeks using 5 interrupted sutures. The rats were divided into 4 groups (control, gentamicin, fibrin glue, and combination). On postoperative days 3 and 5, the rats in each group were killed, anastomotic bursting pressures scores and bowel loop adhesions were determined, and histologic examination was performed. RESULTS: No significant difference was noted in the bursting pressures, adhesions, inflammatory infiltrates, fibroblasts, or neoangiogenesis between the fibrin-glue only and the combination groups for both the day 3 and day 5 subgroups. CONCLUSIONS: The combination of topical gentamicin and fibrin glue had little effect because the combination did not provide additional anastomotic strength or decrease the number of adhesions when compared with fibrin glue alone.

A novel nonoperative orthotopic colorectal cancer murine model using electrocoagulation.

BACKGROUND: Orthotopic mouse models of human colorectal cancer represent an important in vivo tool for testing chemotherapeutic agents and studying intraluminal factors that may alter the growth of cancers. Currently the orthotopic mouse models of colorectal cancer require either an operative procedure or creation of colitis to implant the cancer cells in rectum. We have developed a nonoperative, minimally invasive technique to create a true orthotopic colon cancer mouse model. STUDY DESIGN: We used human (LS 174T and HT-29) and murine (CRL-2638 and CRL-2639) colon cancer cell lines. Low-dose mucosal coagulation was performed transanally using a specially designed electrode at 1 to 3 predetermined points, 2 to 3 cm from the anus, followed by a transanal instillation of tumor cells (1 × 10(6) cells) in 12 female nude or severe combined immunodeficiency disease mice for each of the 4 groups (n = 48, plus 16 controls). Mouse colonoscope (Coloview) and microCT were used to follow tumor growth. Four mice from each group were euthanized at 1, 2, and 3 weeks. RESULTS: Tumors were detected in 12 of 12 of the CRL-2638, 11 of 12 of the CRL-2639, 7 of 12 of the HT-29 and 12 of 12 mice in the LS 174T groups. Histopathologic evaluation showed that the tumors grew from the colonic mucosa. CRL-2638 and LS 174T exhibited better implantation, faster tumor growth, larger tumor volume, and earlier metastases. MicroCT detected tumors larger than 3 mm, and the colonoscopy detected tumors larger than 1 mm. CONCLUSIONS: Our mouse model is minimally invasive and easy to create and overcomes the limitations of existing models while mimicking the human disease in terms of morphology and biologic behavior. This model opens the doors for colon cancer oncologic studies in an animal model that were previously not possible.

Protective effect of methylprednisolone on warm ischemia-reperfusion injury in a cholestatic rat liver.

BACKGROUND: Cholestasis has been identified as a risk factor for oxidative stress, and it potentially enhances after ischemic-reperfusion injury. The aim of this study was to evaluate the role of methylprednisolone on warm ischemia-reperfusion injury in the presence of cholestasis. METHODS: A reversible cholestatic rat model was created. After 7 days, rats received 30 mg/kg of intravenous methylprednisolone 2 hours before ischemia, followed by 30 minutes of ischemia. Rats were euthanized 24 hours after ischemia. Serum aspartate aminotransferase and interleukin-6 were measured, and the liver was harvested for histology and myeloperoxidase estimation. RESULTS: Methylprednisolone had a protective effect, with a statistically significant decrease in aspartate aminotransferase (P=.01) and a trend toward decreased levels of interleukin-6 (P=.07). Histology showed a significant difference in architectural distortion (P=.01), cytoplasmic vacuolation (P=.01), and nodular hepatocellular necrosis (P=.04). CONCLUSIONS: Methylprednisolone attenuated the ischemic-reperfusion injury in the presence of cholestasis and can be considered for clinical use in the presence of cholestasis.

Transphyseal bioabsorbable screws cause temporary growth retardation in rabbit femur.

A self-reinforced bioabsorbable poly-L-lactide/polyglycolide (SR-PLGA) 80/20 screw 2.0 mm in diameter was implanted transphyseally across the distal growth plate of the right femur in 24 immature rabbits. Radiologic evaluation revealed a mean shortening of 3.1 mm at 3 weeks, 11.1 mm at 6 weeks, 9.3 mm at 24 weeks, 9.0 mm at 48 weeks, and 12.6 mm at 72 weeks compared with the intact contralateral femur. In 13 control rabbits, drilling without screw placement did not cause any statistically significant femoral shortening. Therefore, the transphyseal SR-PLGA 80/20 screw caused growth retardation for 6 weeks postoperatively, after which the normal growth tendency was recovered until the growth plate was closed. The duration of temporary growth retardation correlated with that of strength retention of the SR-PLGA 80/20 copolymer. These findings suggest that SR-PLGA 80/20 screws can be applied in transphyseal bone fixation. The use of bioabsorbable screws for temporary epiphysiodesis seems attractive but requires further study.

Evaluation of 45S5 bioactive glass combined as a bone substitute in the reconstruction of critical size calvarial defects in rabbits.

Biomaterial research and tissue engineering have guided new developments in bone replacement. In this study, the osteoconductive and osteoinductive properties of 45S5 Bioglass (Novabone-C/M, Porex Surg., Newnan, GA), granules as a bone replacement material for large calvarial defects were evaluated. Rabbit periosteal cells were expanded in culture and used in vivo. Alkaline-phosphatase assay, collagen type I, and calcium expression were applied to confirm osteoblast phenotype. In the in vivo phase, a 15-mm diameter critical size calvarial defect was created in rabbits (n = 14). The defect was reconstructed according to four treatment groups: autogenous bone (n = 2), Bioglass alone (n = 2), Bioglass + bone (n = 5), Bioglass + periosteal cells (n = 5). The animals were killed 12 weeks after surgery, and the samples were analyzed. Periosteal cells grew successfully in vitro. Because of their fast proliferation and potential to differentiate into osteoblasts, they were an excellent source of cells for bone tissue engineering. The best ossification was seen when autogenous bone was used (79.4% ossified), whereas only 8.2% of the defect in the Bioglass group showed ossification. Addition of bone or cells to the Bioglass increased the area of ossification to 42.7% and 30.2%, respectively. Defects replaced with Bioglass showed varying degrees of inflammatory reaction because of the intense cell-mediated biodegradation process. Based on these findings, the use of Bioglass granules to repair large craniofacial defects cannot be advised.

Deep circumflex iliac cutaneous free flap in cats.

OBJECTIVE: To develop and assess the survival of a microvascular cutaneous free flap based on the ventral branch of the deep circumflex iliac (DCI) artery and vein in cats. STUDY DESIGN: Experimental study. ANIMALS: Phase 1: 6 feline cadavers; Phase 2: 2 adult cats; Phase 3: 10 adult cats. METHODS: Phase 1: Selective angiographic study of the deep circumflex iliac artery was completed in 6 feline cadavers. After injection of the DCI artery with barium, high-detail radiographs were made of skin flaps harvested from the lateral flank and thigh region. The extent of the cutaneous angiosome was mapped with regard to the underlying anatomical landmarks. Phase 2: An island flap based on anatomic boundaries of the DCI angiosome derived from phase 1 of the study was elevated in 2 cats. Flaps were observed for 3 weeks for survival. Phase 3: Free skin flaps based on the DCI vessels were harvested in 10 cats and transferred to the dorsal interscapular region. Flaps were evaluated for 2 weeks for survival. Tissue samples were collected for histopathology, and angiograms of the flaps were completed. RESULTS: Phase 1: Angiograms revealed a large primary cutaneous angiosome of the DCI artery located over the lateral femoral region, which extended from the iliac crest to the level of the patella. Phase 2: All island flaps survived for 3 weeks. Phase 3: Six free flaps survived for 2 weeks, and 4 flaps failed completely. Failure of 1 flap occurred because of avulsion of the venous and arterial anastomosis postoperatively. Another cat had intraoperative hemorrhage, which resulted in anemia and hypovolemia and likely caused the flap to fail. The other 2 flaps that failed had poor perfusion intraoperatively and had the longest ischemia times. CONCLUSIONS: The cutaneous DCI free flap in cats may be clinically useful in reconstruction of large cutaneous wounds. The length of ischemia time for successful cutaneous free flap transfer in the cat may be shorter than in other species. CLINICAL RELEVANCE: Large wounds created by trauma or oncologic ablative surgery in cats could be reconstructed with cutaneous microvascular free flap. Additional studies assessing the critical ischemia time of cutaneous flaps in cats and evaluating the use of this flap clinically are needed.