A novel flexible endoluminal stapling device for use in NOTES colotomy closure: a feasibility study using an ex vivo porcine model

Background  

With advances in endoscopic diagnosis of early-stage gastrointestinal pathology, the need to offer minimally invasive treatment is attracting significant interest. It is essential that secure and consistent closure of full-thickness colonic resections and colotomy access be provided in natural orifice translumenal surgery (NOTES). This ex vivo porcine study aimed to evaluate a novel prototype flexible endoscopic stapler device for use in closure of full-thickness colonic defects.     

Division of the small bowel with the LigaSure Atlas device during the right laparoscopic colectomy

BACKGROUND: Bowel division and anastomosis were facilitated greatly with the advent of stapling techniques. Since then, there have not been any new evolving technologies to facilitate these maneuvers. For this reason, we recently applied the LigaSure Atlas device (Valleylab, Boulder, CO) to the division of the small bowel during this procedure to obtain a reliable and low-cost division of the ileum. METHODS: After vessel ligation and ileocolic mobilization, the terminal ileum is sealed and divided with the LigaSure Atlas. This device is applied sequentially along the small bowel twice to ensure an adequate seal before the cut. A terminolateral ileotransversostomy is performed extracorporeally with a mechanical circular stapling device, installing the anvil of the circular stapler into the ileal stump. RESULTS: We have not encountered any problems with this technique since its introduction in our institution, and no leakage or bursting of the ileal stumps. CONCLUSIONS: This technique enables an easy, reliable, and inexpensive technical option to optimize the right laparoscopic colectomy procedure.     

LigaSure in laparoscopic transperitoneal heminephroureterectomy in children: a comparative study

Background: This study was conducted to evaluate the feasibility of using the LigaSure vessel sealing system (Valleylab, Boulder, CO) in laparoscopic transperitoneal vs. open retroperitoneal heminephroureterectomy in children. Materials and Methods: Seven consecutive patients with impaired renal duplex systems underwent laparoscopic heminephroureterectomies using LigaSure between April 2003 and April 2005. The operative time, complications, and hospital stay were analyzed prospectively. The data of 7 consecutive patients who had undergone open retroperitoneal heminephroureterectomy from 2001 to 2003 were analyzed for comparison purposes. The mean ages, underlying disease, and location of the affected kidney pole were not significantly different between these groups. Results: There were no intraoperative complications during laparoscopic heminephroureterectomy and all procedures were completed laparoscopically. The mean operative time of 144 minutes (range, 90-210 minutes) for laparoscopic heminephroureterectomy was somewhat longer than in open heminephroureterectomy-mean time 110 minutes (range, 60-165 minutes) (P = 0.5). Complications of open retroperitoneal heminephroureterectomy included bleeding of the surface of the remaining kidney pole in one patient, requiring extensive hemostatic suturing. Postoperative recovery was uneventful in all laparoscopic procedures, whereas intermittent retention of urine was noticed in one patient undergoing the open procedure. Conclusion: Laparoscopic heminephroureterectomy using LigaSure is feasible in children and has a similar operative time compared to conventional heminephroureterectomy.     

Radiofrequency-induced small bowel thermofusion: an ex vivo study of intestinal seal adequacy using mechanical and imaging modalities

Background

Bipolar radiofrequency (RF) induced tissue fusion is believed to have the potential to seal and anastomose intestinal tissue thereby providing an alternative to current techniques which are associated with technical and functional complications. This study examines the mechanical and cellular effects of RF energy and varying compressive pressures when applied to create ex vivo intestinal seals.

Methods

A total of 299 mucosa-to-mucosa fusions were formed on ex vivo porcine small bowel segments using a prototype bipolar RF device powered by a closed-loop, feedback-controlled RF generator. Compressive pressures were increased at 0.05 MPa intervals from 0.00 to 0.49 MPa and RF energy was applied for a set time period to achieve bowel tissue fusion. Seal strength was subsequently assessed using burst pressure and tensile strength testing, whilst morphological changes were determined through light microscopy. To further identify the subcellular tissue changes that occur as a result of RF energy application, the collagen matrix in the fused area of a single bowel segment sealed at an optimal pressure was examined using transmission electron microscopy (TEM).

Results

An optimal applied compressive pressure range was observed between 0.10 and 0.25 MPa. Light microscopy demonstrated a step change between fused and unfused tissues but was ineffective in distinguishing between pressure levels once tissues were sealed. Non uniform collagen damage was observed in the sealed tissue area using TEM, with some areas showing complete collagen denaturation and others showing none, despite the seal being complete. This finding has not been described previously in RF-fused tissue and may have implications for in vivo healing.

Conclusions

This study shows that both bipolar RF energy and optimal compressive pressures are needed to create strong intestinal seals. This finding suggests that RF fusion technology can be effectively applied for bowel sealing and may lead to the development of novel anastomosis tools.     

Hemostatic properties of four devices for partial nephrectomy: a comparative ex vivo study

PURPOSE: Laparoscopic partial nephrectomy (LPN) is a common minimally-invasive treatment modality for renal tumors, and achieving hemostasis during excision is a major challenge. The aim of our study was to investigate the hemostatic potential of four different devices for realizing this under standardized conditions. MATERIALS AND METHODS: LPN was performed on a standardized model of blood-perfused ex-vivo porcine kidneys. Each of the four devices (Greenlight KTP laser, Habib Sealer, LigaSure, and SonoSurg) as well as a scalpel (for comparison) were used to perform 10 excisions with the renal artery and vein clamped, and another 10 were performed with no clamping. Treatment time (TT), blood loss (BL), and the ease of handling of the device were measured and histologic examination of the margins was carried out. RESULTS: In general, TT was faster and there was less BL with clamping than without in all cases. TT was shortest for the KTP laser (6.07+/-1.2 minutes; P<0.0001), followed by the LigaSure (8.78+/-0.42 minutes), the SonoSurg (15.9+/-1.28 minutes), and the Habib (21.7+/-3.4 min). The SonoSurg showed a significantly higher BL without clamping (66+/-6 ml, p<0.0001) but there were no significant differences between the other devices. With clamping, BL four all four devices was comparable (13+/-2 ml) and without statistical significance (p=0.5). TT was shortest for the KTP laser (3.27+/-0.55 min, p<0.0001) followed by the LigaSure (6.47+/-0.38 s), the SonoSurg (8.35+/-3 min) and the Habib (9.71+/-1.18 minutes). The excised surface was completely coagulated for all of the devices except for the SonoSurg. CONCLUSION: Our ex-vivo study suggests that hemostatic potential and the coagulative effect of all four devices is inadequate. Furthermore, none of the devices produced clean and sharp resection margins, which is a prerequisite for negative surgical margins.     

Aortic Slimgraft: ex vivo and in vivo study

In this article we describe a method for assembling an endovascular graft within the aorta with a graft and then a stent introduced sequentially over a guidewire as separate components. In the ex vivo study, an endovascular graft that was 25 mm in diameter was introduced through a 9F introducer. In the in vivo study, smaller endovascular grafts were placed in the aortas of four healthy pigs and five pigs with aortic aneurysms. Our data suggest that this very low profile system may have significant clinical implications because it converts aortic repair into a percutaneous procedure.     

The use of the Angioseal device for femoral artery closure

BACKGROUND: As vascular surgeons perform increasing numbers of percutaneous catheter-based procedures, they will need to become familiar with varying methods of femoral artery closure. Few studies on closure devices have included significant numbers of patients with peripheral arterial disease. It is the purpose of this study to determine whether the Angioseal device (St. Jude Medical) is a satisfactory method of achieving femoral artery puncture site hemostasis in these patients. METHODS: The records of all patients undergoing Angioseal closure of femoral artery puncture by a single vascular surgeon were reviewed. Indication, type of intervention, and size of the vascular sheath employed were recorded. Times to mobilization and discharge were determined. Patients were seen before discharge and 1, 4, and 12 weeks after the procedure, and at 3- month intervals thereafter. Complications including hemorrhage, pseudoaneurysm, infection, and vessel occlusion were noted. RESULTS: Between February 1, 2002, and August 31, 2003, 220 Angioseal collagen plugs were deployed in 188 patients. Attempts were made to deploy Angioseal devices in 92% of patients undergoing percutaneous procedures during this time period. One hundred forty-four procedures were diagnostic and 74 procedures included 76 therapeutic interventions. One hundred forty-four 5F sheaths, 47 6F sheaths, and 29 7F sheaths were employed during the procedures. Time to mobilization and discharge was 58 +/- 19 minutes and 102 +/- 31 minutes in patients undergoing diagnostic studies, 68 +/- 22 minutes and 146 +/- 42 minutes following interventions using 6F sheaths, and 127 +/- 18 minutes and 219 +/- 37 minutes when interventions were performed using 7F sheaths. No patient developed a major hematoma or infection following the use of an Angioseal. There were 2 complications related to device deployment. One patient developed a 1.4-cm false aneurysm at the femoral artery puncture site that resolved spontaneously. A second patient required operation for vessel occlusion when an Angioseal was deployed in a markedly diseased femoral artery. These adverse events occurred early in our experience. CONCLUSIONS: The Angioseal provides a secure method of achieving hemostasis following femoral artery puncture. It is easy to deploy, has a high level of patient satisfaction, and allows for early ambulation and hospital discharge. When simple guidelines are observed, the device can be safely used in the great majority of patients with peripheral vascular disease. It offers considerable advantages over the traditional method of manual compression.     

Protective effects of ex vivo graft radiation and tacrolimus on syngeneic transplanted rat small bowel motility

BACKGROUND: Intestinal transplantation is unduly complicated by the nontolerogenic properties of the gut-associated lymphoid tissue. Because simultaneous graft irradiation and bone marrow infusion significantly prolong the survival of the small bowel transplanted animal, our objective was to determine the functional motility effects of the immune modulating, graft irradiation procedure in the presence and absence of tacrolimus immunosuppression. METHODS: Four groups of syngeneic orthotopic small bowel transplanted animals were studied 48 hours after operations (untreated, tacrolimus, ex vivo graft irradiation, and tacrolimus + irradiation) and compared with controls. Histologic analysis was performed for mucosal apoptosis and neutrophilic infiltration into the muscularis externa. Gastrointestinal in vivo transit and in vitro circular muscle strip contractions were quantified in response to bethanechol (0.3-300 micromol/L). RESULTS: Graft irradiation ex vivo alone or in the presence of tacrolimus significantly increases (> 10-fold) the number of apoptotic mucosal cells after transplantation. Functional measurements showed that transplantation resulted in a significant delay in gastrointestinal transit and a decrease in muscle strip contractility. Tacrolimus and graft irradiation significantly ameliorated the transplant-induced dysfunction. CONCLUSIONS: Given the endowed propensity of mucosal regeneration, the immunologic and functional benefits of ex vivo graft irradiation appear to outweigh the detrimental effects to the mucosa.     

The application of the V-Loc closure device for gastrointestinal sutures: a preliminary study

Background

Leakage is one of the major complications in gastrointestinal surgery. This preliminary study compared a new barbed absorbable thread for gastrointestinal sutures with monofil suture material in a cadaver model.

Methods

In this study, mechanical experiments were performed in 20 recently deceased individuals. Incisions were made in the small intestine, colon, and stomach, and then sutures were created with the V-Loc closure device and monofil suture material. Intestinal bursting pressure was measured by inserting a balloon and slowly filling it with air until there was a dehiscence, or wall or suture rupture.

Results

The bursting pressures differed significantly between the two sutures in the small intestine, showing the advantage of the V-Loc closure device, which had a mean bursting pressure of 116.2 mmHg compared with 110 mmHg for the monofil suture (p = 0.003). The mean bursting pressure did not differ significantly between the two sutures in the colon and the stomach. The mean bursting pressures for the V-Loc closure device were 141.3 mmHg (stomach) and 137.2 mmHg (colon) compared with the monofil suture material bursting pressures of 133 mmHg (stomach) and 134.8 mmHg (colon).

Conclusions

Because the bursting strength of the sutures created with monofil suture material differs significantly from that of the V-Loc closure device, the V-Loc suture material should be used for gastrointestinal sutures. Although the two sutures did not differ significantly in the colon or the stomach, the V-Loc closure device should be used for these as well because its advantages may overrule those of the monofil suture. No knot tying is required, and the operating time can be shorter. Especially for laparoscopic surgery, the V-Loc closure device is recommended.     

Effect of FTY720 and ex vivo graft irradiation in rat small bowel transplantation: apoptosis of crypt cells and lymphocytes

OBJECTIVE: We investigated the extent of apoptosis in crypt cells and Peyer's patches (PPs) during small bowel allograft rejection in rats to examine the effect of FTY720 and ex vivo graft irradiation during rejection. MATERIALS AND METHODS: Orthotopic small bowel transplantations (SBT) were performed from Brown Norway (BN) rats to Lewis (LEW) rats. Four groups of SBT animals were studied on days 3, 5, and 7 after operations: untreated allograft, allograft with FTY720, allograft with irradiation, and allograft with FTY720+irradiation. Cryostat sections were prepared from the grafts, including PPs. An in situ end-labeling (ISEL) technique was used to detect apoptotic cells. Indirect immunoperoxidase staining was also performed using monoclonal antibodies against rat Fas/FasL. RESULTS: The graft survival was prolonged in the FTY720-treated groups. In the FTY720-treated group, the number of ISEL-positive enterocytes was significantly down-regulated on days 3, 5, and 7 compared with the untreated allograft group. The number of ISEL-positive mononuclear cells was also significantly down-regulated compared with the untreated allograft group. The FTY720 the radiation and the FTY720+irradiation treated groups showed significantly down-regulated numbers of Fas/FasL-positive enterocytes on day 7 compared with the untreated allograft group. Fas/FasL-positive mononuclear cells were also significantly down-regulated in the allograft compared with the untreated allograft group. CONCLUSIONS: FTY720 and ex vivo graft irradiation prevented up-regulation of the number of apoptotic enterocytes, lymphocytes, and Fas/FasL-positive lymphocytes, and also prolonged small bowel allograft survival. Combination FTY720 and ex vivo graft irradiation did not affect graft survival and apoptotic cell expression compared with the FTY720 only group. These findings suggest that FTY720 may prevent both rejection-associated and sepsis-induced apoptosis during the late phase of small bowel graft rejection.     

The use of LigaSure in patients with hyperthyroidism

Background Thyroidectomies of hyperthyroidic patients are known to be more blood-spattered than the operations performed for euthyroid nodular diseases and require careful hemostasis. Our purpose was to evaluate the efficacy of the use of LigaSure in patients with hyperthyroidism.Materials and methods Between January 2004 and October 2005, 100 patients underwent total or near-total thyroidectomy. Bipolar vessel ligation system (LigaSure) was the choice of modality for hemostasis in half of these patients, and the conventional suture ligation technique was used for the rest. The following data were evaluated non-randomized and prospectively in this study: patients demographics, thyroid pathology, operative duration, presence of complications, and the duration of the hospital stay. Comparisons of the data were evaluated by the Wilcoxon and chi-square tests.Results Among the patients of the LigaSure group, 14 patients were detected to have hyperthyroidism (seven patients with Graves’ disease and another seven patients with multinodular toxic goiter), while 36 patients were found to be euthyroidic. The durations of the operation time and of the hospital stay of the patients in the LigaSure group were significantly lower than the conventional thyroidectomy group (p<0.05). The complication rates of the LigaSure and conventional thyroidectomy groups were 4 and 6%, respectively (p>0.05).Conclusions The use of LigaSure as an operative technique in the treatment of Graves’ disease and toxic goiter is a safe and effective modality that provides a shorter hospital stay and a shorter operation time as well.Presented at the International Symposium “Modern Technologies in Thyroid Surgery”, 10–11 February 2006, Halle/Saale, Germany     

Simplifying four-strand flexor tendon repair using double-stranded suture: a comparative ex vivo study on tensile strength and bulking

We have compared a simple four-strand flexor tendon repair, the single cross-stitch locked repair using a double-stranded suture (dsSCL) against two other four-strand repairs: the Pennington modified Kessler with double-stranded suture (dsPMK); and the cruciate cross-stitch locked repair with single-stranded suture (Modified Sandow). Thirty fresh frozen cadaveric flexor digitorum profundus tendons were transected and repaired with one of the core repair techniques using identical suture material and reinforced with identical peripheral sutures. Bulking at the repair site and tendon-suture junctions was measured. The tendons were subjected to linear load-to-failure testing. Results showed no significant difference in ultimate tensile strength between the Modified Sandow (36.8 N) and dsSCL (32.6 N) whereas the dsPMK was significantly weaker (26.8 N). There were no significant differences in 2 mm gap force, stiffness or bulk between the three repairs. We concluded that the simpler dsSCL repair is comparable to the modified Sandow repair in tensile strength, stiffness and bulking.     

Measurement of radical-scavenging ability in small bowel ischemia/reperfusion injury in rats using an in vivo and ex vivo electron paramagnetic resonance technique

Reperfusion of ischemic tissues results in the formation of toxic reactive oxygen species (ROS), such as superoxide anion, hydroxyl radicals, hydroperoxide, and peroxynitrite. ROS are potent oxidizing agents, fully capable of damaging cellular membranes by lipid peroxidation. In this study, we applied for the first time the in vivo electron paramagnetic resonance (EPR)/spin probe and ex vivo EPR technique to provide direct evidence of ROS following experimentally induced small bowel ischemia/reperfusion (I/R) injury. The decay rate (spin clearance rate) was determined over the first 3 minutes at 6 hours after reperfusion. Decay rates in rats subjected to I/R injury were lower than those in the sham group. Superoxide scavenging activity (SSA) in rats subjected to I/R injury was significantly lower than that in the sham group. In conclusion, this study demonstrated that it is possible to detect the accumulation of ROS following experimentally induced small intestine I/R injury using an in vivo and an ex vivo EPR technique with a spin probe.