Hemostatic Capability of a Novel Tetra-Polyethylene Glycol Hydrogel.

BACKGROUND: TetraStat is a tetra-armed polyethylene glycol (PEG) hydrogel. It is a synthetic sealant that solidifies instantly in response to pH changes. This study aimed to evaluate the hemostatic effect of TetraStat through experiments evaluating future clinical applications. METHODS: We used TetraStat, oxidized regenerated cellulose (SURGICEL®), and fibrinogen and thrombin sealant patch (TachoSil®) using in vitro and in vivo experiments. For the in vitro experiment, a closed circulatory system filled with phosphate-buffered saline under high pressure was used. Needle punctures were created and closed using the various sealants. For the in vivo experiment, rat venae cavae were punctured with 18- and 20-gauge (G) needles, and hemorrhage was allowed to occur for several seconds. A porous PEG sponge soaked with TetraStat was applied as a hemostatic system. Hemostasis outcomes were compared among the various concentrations (40-100 g/L) of TetraStat, SURGICEL, and TachoSil. RESULTS: The punctured holes in the prosthetic graft were successfully sealed with TetraStat in 1 min. The success rate of hemostasis with TetraStat for the punctured holes in the rat vena cava was dose-dependent. TetraStat was effective in sealing the holes created with a 20 G needle at all concentrations; however, the holes created with an 18 G needle could be sealed only when the concentration ≥60 g/L. Hemostasis using SURGICEL or TachoSil was less successful and sometimes required up to 5 min. CONCLUSIONS: TetraStat has a high hemostatic ability. A porous PEG sponge soaked with TetraStat is a useful choice for effective hemostasis during massive hemorrhage.

Ten-Hour Simulation Training Improved the Suturing Performance of Medical Students.

PURPOSE: We evaluated the effectiveness of an original simulation training system in improving the suturing performance of medical students using a previously developed web application for scoring suturing performance. METHODS: Medical students were recruited for this study and trained on vascular graft anastomosis. Prosthetic grafts were anastomosed and evaluated after orientation, and after 1 hr and 10 hr after training. Vascular surgeons were recruited as controls. Using a previously developed web application, suturing performance was evaluated on the basis of procedural time, coefficient of variation of bite (length of a stitch across the graft), coefficient of variation of pitch (interval between stitches), and skewness (symmetry of the angles between stitches). RESULTS: Forty-eight medical students and 10 vascular surgeons were recruited. After 1 hr of training, only the students' procedural time improved. After 10 hr of training, all scores improved compared with those in the first trial, and all students' scores except procedural time were statistically similar to those of the vascular surgeons. CONCLUSIONS: Ten-hour training improved all factors, including bite, pitch, skewness, and time. Our simple and inexpensive training system and web application for calculating anastomosis scores can be a useful open educational resource.

Sac enlargement due to perigraft seroma and back-bleeding from the remnant wall 11 years after open surgical repair of an infected abdominal aortic aneurysm.

We describe a case of sac enlargement that occurred 11 years after emergent open surgical repair of an infected abdominal aortic aneurysm. The diameter of the sac covering the Dacron graft had gradually expanded to 80 mm, and the flow of contrast medium into the sac was suspected. Elective surgery revealed a perigraft seroma and back-bleeding from the remnant wall. After attaining hemostasis, fibrin glue and oxidized cellulose were applied, and sac plication was performed. Thereafter, the sac has not expanded. Open diagnostic treatment should be a good option for cases of postoperative sac enlargement with an unknown origin.

A comparison of subjective clinical and objective judgement of abdominal aortic aneurysm morphology.

BACKGROUND: We compared the subjective, clinical judgement of "saccular" morphology with the objective judgement of mechanical structural analysis. METHODS: Using structural analysis with the finite element method, we previously created a simple model of abdominal aortic aneurysm (AAA) that visualized the distribution of the maximum principal stress (MPS) in the aortic wall and identified the area of prominent stress. AAA "saccular" morphology was determined according to the area showing MPS>0.03 MPa. AAAs with low aspect ratio (horizontally long AAA sac) and small fillet radius were defined as "saccular." Twelve vascular surgeons were recruited. First, they judged the AAA as saccular or fusiform with 3-dimensional images at their clinical impression (subjective "eyeball" judgement). Second, they applied the deformable figure tools on the simple AAA-shaped sagittal view in the application model for 30 AAA cases. From the data of the tools applied, the mechanical structural analysis was performed semi-automatically and the morphology was judged with the objective "simple application." RESULTS: The structural analysis revealed that only one case was judged as saccular by 11 out of 12 surgeons and the other 29 AAAs were judged as fusiform by two-thirds or more of the surgeons. In contrast, 5 cases were subjectively judged as saccular by eight and more of the surgeons. CONCLUSIONS: The clinical judgement of AAA saccular morphology by the vascular surgeons was different from the judgement derived from the mechanical structural analysis using the application model. The saccular morphology may be theoretically rare in AAAs.

A hybrid procedure for middle colic artery aneurysm complicated by chronic juxtarenal segmental aortic occlusion.

Here we describe a hybrid procedure, that is, a combination of open isolation and coil embolization, to treat a saccular middle colic artery aneurysm deep behind the pancreas. The middle colic artery provided the collateral blood flow necessary to bypass a chronic segmental aortic occlusion. For preservation of the collateral vessels, we surgically excluded and bypassed the aneurysm and then performed endovascular embolization of the pancreaticoduodenal arteries flowing into the aneurysm, resulting in complete isolation of the aneurysm without jeopardizing blood flow. This hybrid procedure for visceral artery aneurysms can be effective when the collateral vessels need to be preserved.

Phlegmasia cerulea dolens as an initial manifestation of a fistula between a ruptured iliac artery aneurysm and the iliac vein.

Phlegmasia cerulea dolens (PCD) is caused by obstruction of limb venous return that may result in venous gangrene and limb loss. We present a case of a fistula between a ruptured right common iliac artery aneurysm and the left common iliac vein (ilioiliac arteriovenous fistula [AVF]), which initially manifested as left PCD and acute renal failure. Resection of the aneurysm and repair of the AVF immediately improved the PCD and acute renal failure. We should be aware that an iliac AVF might present as PCD and should keep this in mind.

Original Homebuilt Off-the-Job Training System for Vascular Surgeons: System Analysis and Assessment.

Objective: We assessed the effectiveness and appropriateness of our original off-the-job training (Off JT) system using data acquired from recruited medical students and doctors. Materials and Methods: We presented our original homebuilt Off JT system, which is simple and inexpensive. In our unique system, we performed anastomosis at the bottom of a plastic pot, which mimics the actual open surgical procedure at a deep site. There were four evaluation points: (A) operating time, (B) performance of anastomosis by semi-automatically analyzing the image with the coefficient of variation (standard deviation/length) of the "bite" and the "pitch," (C) scoring of the total surgical skill evaluated by the trainers according to the Operative Performance Rating System (OPRS), and (D) the relationship of these three factors (A, B, and C). Results: The procedural time and coefficient of variation of the bite and pitch decreased and the OPRS score increased after training. There was a strong correlation between procedural time, anastomotic performance, and OPRS score. Conclusion: The effectiveness of our original homebuilt system was shown by reduced procedural time, improved anastomotic quality, and increased OPRS score.