Profiling surgical staplers: effect of staple height, buttress, and overlap on staple line failure.

BACKGROUND: Few studies have been designed to assess the performance of surgical staplers. In this study, we analyzed the effect of staple height, buttressing, and overlapping of staple lines on staple line failure. METHODS: Staple lines created on fresh porcine small bowel segments ex vivo were tested for leak pressure by insufflating air into the bowel under water and recording pressure at failure. Three separate experiments were done and included staple height (white, 2.5 mm, n = 16; blue, 3.5 mm, n = 16; green, 4.1 mm, n = 16; one half of them buttressed); the absence (n = 12) or presence (n = 12) of an overlap in 3.5-mm staple lines; and the absence (n = 14) or presence (n = 11) of buttresses in 3.5-mm overlapping staple lines. Data are reported in median values and ranges; nonparametric tests were used for data analysis. RESULTS: In the porcine small bowel, leak pressure was related to staple height; green loads had the worst profile (35 mm Hg, range 19-105) compared with the blue (79 mm Hg, range 9-177), and white (108 mm Hg, range 28-280) loads (P = .006). Buttressing uniformly improved leak pressure for all staple loads (P <.0001). No significant difference was found between lines with overlapping (59 mm Hg, range 32-121) and those without (42 mm Hg, range 22-75; P = .162). Buttressing also improved the leak pressure of overlapping staple lines from 65 mm Hg (range 47-121) to 93 mm Hg (range 75-187; P = .0014). CONCLUSION: Great variability was found in the leak pressures among the different applications of the same stapler. Staple height is an important determinant of leak pressure. The presence of an overlap did not affect leak pressure; in fact, a trend toward improvement was seen with overlapping staple lines. Buttressing improved all types of staple lines.

A novel constrained, paclitaxel-coated angioplasty balloon catheter.

AIMS: The study aimed to assess drug adherence, transfer to the vessel wall, tolerance and efficacy of a constrained angioplasty balloon coated with an excipient-enhanced paclitaxel coating (Chocolate coated balloon [CCB]) in the porcine model. METHODS AND RESULTS: Drug adherence was investigated in vitro. Drug transfer was evaluated in porcine arteries. A stent overstretch model was chosen to provoke intimal thickening in the efficacy and tolerance study. Conventional uncoated balloons were used as controls. CCB were coated with a nominal (3 µg/mm2) and high dose (two completely overlapping inflations each at 6 µg/mm2) of paclitaxel. Efficacy was assessed by histomorphometry and quantitative coronary angiography (QCA). Tolerance, including potential downstream effects, was assessed by myocardial function and histopathology. The CCB lost 6±12% of dose during in vitro simulated delivery to the lesion; drug transfer to the vessel wall was 14±4%. QCA and histomorphometry revealed no baseline differences between treatment groups. Thirty days after treatment, both doses of the CCB resulted in a 50% reduction in neointimal thickening of arteries relative to the uncoated balloon group. Maximum neointimal thickness was 1.12±0.36 mm for uncoated control specimens and 0.46±0.06 mm and 0.44±0.30 mm for the two CCB doses (3 and 2×6 µg/mm2), respectively. There were no device-related animal deaths or changes in left ventricular ejection fraction or device-specific myocardial histopathologies. There were no statistically significant differences between inflammatory scores among treatment groups. CONCLUSIONS: The results demonstrate efficacy and tolerance of a mechanically unique constrained angioplasty balloon within the tested dose range of the selected paclitaxel coating in the chosen porcine preclinical model.

Molecular imaging and radioimmunoguided surgery.

Molecular imaging comprises a series of diagnostic modalities that provide information on the physiology and molecular composition of cells and tissues. One of these modalities, radioimmunodetection, uses radiolabeled monoclonal antibodies (mAbs) to image tissues. Two radioimmunodetection modalities are described in this article: immunoscintigraphy and radioimmunoguided surgery (RIGS). In immunoscintigraphy, the radioactivity is measured with the use of an external gamma camera and used to create images. In RIGS, the radioactivity is detected intraoperatively with the use of a handheld gamma probe to help the surgeon detect foci of otherwise occult disease. Both techniques have the potential to improve the preoperative and intraoperative localization of cancer. Multiple studies have been performed on the efficacy of RIGS on different malignancies, especially colorectal cancer. Despite the good sensitivity of the technique, some concerns revolve around the high rate of false positives and the real significance of leaving RIGS-positive tissue behind in terms of long-term outcomes and survival. More studies are warranted to further develop the technique and determine the specific role it will play on the diagnosis and management of surgical disease. Surgeons should actively participate in these studies and in expanding the applications of this promising technology.

Biomaterials: a primer for surgeons.

Biomaterials offer the surgeon a powerful set of clinical tools for patient treatment and are found in virtually every instrument, device, implant, or piece of equipment in the operating room. In fact, surgeons have historically driven clinical application of biomaterials and stand uniquely positioned to contribute to the ongoing development of biomaterials. Having an understanding of the materials available and their basic properties can contribute to better and more effective outcomes. This article provides an overview of the biomaterials field. It begins with a definition and abbreviated history of the field, highlighting its clinical roots. An introduction to the four material classifications--metals, polymers, ceramics, and composites--is then presented, providing the reader with basic properties of each group and examples of materials. Sections on nanotechnology and tissue engineering also briefly describe development within the field. Finally, the evolution of treatments for pectus excavatum and congenital diaphragmatic hernias are presented, highlighting the role of biomaterials. While providing a primer of the field, this paper shows the broad interdisciplinary reach of material science in surgery and suggests sources for further investigations.

Natural orifice translumenal endoscopic surgery (NOTES).

Surgery has rapidly evolved as new technologies are adopted. With the introduction of laparoscopic surgery, patient outcomes have improved, with faster recovery from smaller incisions. In an effort to continually improve these outcomes and offer alternative options to higher risk patients, a number of investigators have proposed the concept of operating in the peritoneal space through natural orifices, obviating the need for any abdominal skin incisions. Natural orifice translumenal endoscopic surgery (NOTES) offers the same advantages as laparoscopic surgery without skin incisions, and possibly without general anesthesia. This article gives a conceptual and technical description of NOTES, discusses its challenges and potential pitfalls, reviews the early efforts at NOTES-specific device development, and predicts potential future directions of this exciting new area of surgery.

Inventing our future: training the next generation of surgeon innovators.

Current surgical care and technology has evolved over the centuries from the interplay between creative surgeons and new technologies. As both fields become more specialized, that interplay is threatened. A 2-year educational fellowship is described which teaches both the process and the discipline of medical/surgical device innovation. Multi-disciplinary teams (surgeons, engineers, business grads) are assembled to educate a generation of translators, who can bridge the gap between scientific and technologic advances and the needs of the physician and the patient.

Ex vivo analysis of human coronary bifurcation anatomy: defining the main vessel-to-side-branch transition zone.

AIMS: Defining vessel diameters and angles that comprise coronary side-branch intersections could assist in tailoring treatments to match anatomy, improve haemodynamic flow, and minimise mechanical trauma. We sought to characterise intersections of main vessels and side-branches by measuring actual diameters, angles, and shapes at the ostia in human coronary arteries. METHODS AND RESULTS: Polymer casts were created using coronary trees from 23 adult cadaver hearts. Seventy-five arterial intersections between main vessels and side-branches were captured using the combination of a microscope (Smartscope MVP100) and computer program (Gage-X metrology software) specifically calibrated for video-based inspection and measurement (34-fold magnification). The intersection between main vessels and side-branches was a multifaceted, curvilinear transition rather than a bisecting angle. The shape of the ostia was typically elliptical rather than circular. Mean diameters were 2.88 mm in proximal main vessels, 2.34 mm in ostia, and 2.00 mm in side-branches (first-level branches). Obtuse proximal (150 degrees) and distal (111 degrees) angles with accentuated side-branch taper create a "barn door" effect with wider curvature at the bottom. CONCLUSIONS: Matching treatments to these various forms of asymmetry at the main vessel-to-side-branch intersection may minimise injury and optimise scaffolding, and haemodynamic flow.