The iliac bifurcation device for endovascular iliac aneurysm repair: indications, deployment options and results at 1-year follow-up of 25 cases.

BACKGROUND: The iliac bifurcation device (William A Cook Australia, Brisbane, QLD, Australia) is a new endovascular device for iliac aneurysm repair. We review the indications for use, device characteristics, deployment options and the results of our case series. METHODS: The most common indication for deployment is endovascular aortic aneurysm repair (EVAR) with common iliac aneurysm repair. The standard deployment sequence can be adapted to increase the utility of the device. Data were collected prospectively. Follow-up was performed with plain X-ray, ultrasound and computed tomography (CT) scan. RESULTS: Between 2004 and 2007, 25 patients had their common iliac artery aneurysm repaired using the iliac bifurcation device. There were 23 male and 2 female patients. Median age was 75 years (range 60-85). The median follow-up was 12 months (range 1-38). Twenty-one procedures were combined with EVAR. The median abdominal aortic aneurysm diameter was 60 mm (range 31-97), and the median common iliac artery aneurysm diameter was 37 mm (range 24-71). Technical success was achieved in 100% of cases. There were no acute branch vessel occlusions. There was one early type I endoleak (4%). There was one death (4%) in the 30-day period post-procedure. There was one late type I endoleak (4%). CONCLUSIONS: The iliac bifurcation device achieves endovascular common iliac artery aneurysm repair with preservation of internal iliac artery flow. There are multiple different applications of the device and complementary deployment techniques. High rates of technical success and low rates of branch vessel occlusion are possible.

Physical law not natural selection as the major determinant of biological complexity in the subcellular realm: new support for the pre-Darwinian conception of evolution by natural law.

Before Darwin many biologists considered organic forms to be immutable natural forms or types which like inorganic forms such as atoms or crystals are part of a changeless world order and determined by physical law. Adaptations were viewed as secondary modifications of these 'crystal like' abstract afunctional 'givens of physics.' We argue here that much of the emerging picture of biological order in the subcellular realm resembles closely the pre-Darwinian conception of nature. We point out that in the subcellular realm, between nano and micrometers, physical law necessarily plays a far more significant role in organizing matter than in the familiar 'Darwinian world' between millimeters and meters (where matter can be arranged into almost any contingent artifactual arrangement we choose, as witness Lego toys, watches or jumbo jets). Consequently, when deploying matter into complex structures in the subcellular realm the cell must necessarily make extensive use of natural forms-such as the protein and RNA folds, microtubular forms and tensegrity structures-which like atoms or crystals self-organize under the direction of physical law into what are essentially 'pre-Darwinian' afunctional abstract molecular architectures in which adaptations are trivial secondary modifications of what are evidently primary givens of physics.

The protein folds as platonic forms: new support for the pre-Darwinian conception of evolution by natural law.

Before the Darwinian revolution many biologists considered organic forms to be determined by natural law like atoms or crystals and therefore necessary, intrinsic and immutable features of the world order, which will occur throughout the cosmos wherever there is life. The search for the natural determinants of organic form-the celebrated "Laws of Form"-was seen as one of the major tasks of biology. After Darwin, this Platonic conception of form was abandoned and natural selection, not natural law, was increasingly seen to be the main, if not the exclusive, determinant of organic form. However, in the case of one class of very important organic forms-the basic protein folds-advances in protein chemistry since the early 1970s have revealed that they represent a finite set of natural forms, determined by a number of generative constructional rules, like those which govern the formation of atoms or crystals, in which functional adaptations are clearly secondary modifications of primary "givens of physics." The folds are evidently determined by natural law, not natural selection, and are "lawful forms" in the Platonic and pre-Darwinian sense of the word, which are bound to occur everywhere in the universe where the same 20 amino acids are used for their construction. We argue that this is a major discovery which has many important implications regarding the origin of proteins, the origin of life and the fundamental nature of organic form. We speculate that it is unlikely that the folds will prove to be the only case in nature where a set of complex organic forms is determined by natural law, and suggest that natural law may have played a far greater role in the origin and evolution of life than is currently assumed.