The Cardica C-Port System: clinical and angiographic evaluation of a new device for automated, compliant distal anastomoses in coronary artery bypass grafting surgery--a multicenter prospective clinical trial

OBJECTIVES: The C-Port System (Cardica, Inc, Redwood City, Calif) integrates in one tool all functions necessary to enable rapid automated distal coronary anastomoses. The goal of this prospective, nonrandomized, and multicenter study is to determine the safety and efficacy of this novel anastomotic system. METHODS: Five centers enrolled 133 patients awaiting elective coronary artery bypass grafting surgery. Outcome variables were intraoperative device performance, incidence of device-related adverse events, predischarge and 6-month angiographic graft patency, and 12-month clinical outcome. Independent core laboratories performed qualitative and quantitative angiographic and computed tomographic assessments. RESULTS: The C-Port was used to perform a vein-to-coronary anastomosis in 130 patients. Intraoperative conversion to a hand-sewn anastomosis was necessary in 11 patients because of inadequate target site preparation, inappropriate target vessel selection, or both. Inadequate blood flow related to poor runoff required conversion in 3 additional patients. Three patients died before discharge of causes unrelated to the device. At discharge, 113 patients had a C-Port implant in place, and 104 C-Port anastomoses were studied by means of angiography, resulting in 100 FitzGibbon A, 3 FitzGibbon B, and 1 FitzGibbon 0 classifications. At 6 months, one additional patient died of a device-unrelated cause, and 98 patients were evaluated by means of angiography (n = 89). Overall patency (FitzGibbon A) was 92.1%. Three C-Port anastomoses were rated FitzGibbon B, and 4 were rated FitzGibbon 0. At 12 months, 107 (98.2%) of 109 alive patients were followed up, without any reports of device-related major adverse cardiac events. CONCLUSIONS: The C-Port System allows for a rapid, reliable, and compliant distal anastomosis and yields favorable 6-month angiographic and 12-month clinical results when compared with published studies.

Late results after percutaneous closure of patent foramen ovale for secondary prevention of paradoxical embolism using the amplatzer PFO occluder without intraprocedural echocardiography: effect of device size

OBJECTIVES: We sought to assess the safety and clinical efficacy of patent foramen ovale (PFO) closure under fluoroscopic guidance only, without intraprocedural echocardiography. BACKGROUND: Percutaneous PFO closure has been shown to be safe and feasible using several devices. It is generally performed using simultaneously fluoroscopic and transesophageal or intracardiac echocardiographic guidance. Transesophageal echocardiography requires sedation or general anesthesia and intubation to avoid aspiration. Intracardiac echocardiography is costly and has inherent risks. Both lengthen the procedure. The Amplatzer PFO Occluder (AGA Medical Corporation, Golden Valley, Minnesota) can be safely implanted without echocardiographic guidance. METHODS: A total of 620 patients (51 +/- 12 years; 66% male) underwent PFO closure using the Amplatzer PFO Occluder for secondary prevention of presumed paradoxical embolism. Based on size and mobility of the PFO and the interatrial septum, an 18-mm device was used in 50 patients, a 25-mm device in 492, and a 35-mm device in 78. RESULTS: All procedures were successful, with 5 procedural complications (0.8%): 4 arteriovenous fistulae requiring elective surgical correction, and 1 transient ischemic attack. Contrast transesophageal echocardiography at 6 months showed complete closure in 91% of patients, whereas a minimal, moderate, or large residual shunt persisted in 6%, 2%, and 1%, respectively. During a mean follow-up period of 3.0 +/- 1.9 years (median: 2.6 years; total patient-years: 1,871), 5 ischemic strokes, 8 transient ischemic attacks, and no peripheral emboli were reported. Freedom from recurrent ischemic stroke, transient ischemic attack, or peripheral embolism was 99% at 1 year, 99% at 2 years, and 97% at 5 years. CONCLUSIONS: The Amplatzer PFO Occluder affords excellent safety and long-term clinical efficacy of percutaneous PFO closure without intraprocedural echocardiography.

Biomechanical analysis of torsion and shear forces in lumbar and lumbosacral spine segments of nonchondrodystrophic dogs

OBJECTIVE: To determine stiffness and load-displacement curves as a biomechanical response to applied torsion and shear forces in cadaveric canine lumbar and lumbosacral specimens. STUDY DESIGN: Biomechanical study. ANIMALS: Caudal lumbar and lumbosacral functional spine units (FSU) of nonchondrodystrophic large-breed dogs (n=31) with radiographically normal spines. METHODS: FSU from dogs without musculoskeletal disease were tested in torsion in a custom-built spine loading simulator with 6 degrees of freedom, which uses orthogonally mounted electric motors to apply pure axial rotation. For shear tests, specimens were mounted to a custom-made shear-testing device, driven by a servo hydraulic testing machine. Load-displacement curves were recorded for torsion and shear. RESULTS: Left and right torsion stiffness was not different within each FSU level; however, torsional stiffness of L7-S1 was significantly smaller compared with lumbar FSU (L4-5-L6-7). Ventral/dorsal stiffness was significantly different from lateral stiffness within an individual FSU level for L5-6, L6-7, and L7-S1 but not for L4-5. When the data from 4 tested shear directions from the same specimen were pooled, level L5-6 was significantly stiffer than L7-S1. CONCLUSIONS: Increased range of motion of the lumbosacral joint is reflected by an overall decreased shear and rotational stiffness at the lumbosacral FSU. CLINICAL RELEVANCE: Data from dogs with disc degeneration have to be collected, analyzed, and compared with results from our chondrodystrophic large-breed dogs with radiographically normal spines.

Early loading of nonsubmerged titanium implants with a chemically modified sand-blasted and acid-etched surface: 6-month results of a prospective case series study in the posterior mandible focusing on peri-implant crestal bone changes and implant stability quotient (ISQ) values

PURPOSE: The aim of this prospective case series study was to evaluate the short-term success rates of titanium screw-type implants with a chemically modified sand-blasted and acid-etched (mod SLA) surface after 3 weeks of healing. MATERIAL AND METHODS: A total of 56 implants were inserted in the posterior mandible of 40 partially edentulous patients exhibiting bone densities of class I to III. After a healing period of 3 weeks, all implants were functionally loaded with a screw-retained crown or fixed dental prosthesis. The patients were recalled at weeks 4, 7, 12, and 26 for monitoring and assessment of clinical and radiological parameters, including implant stability quotient (ISQ) measurements. RESULTS: None of the implants failed to integrate. However, two implants were considered "spinners" at day 21 and left unloaded for an extended period. Therefore, 96.4% of the inserted implants were loaded according to the protocol tested. All 56 implants including the "spinners" showed favorable clinical and radiographic findings at the 6-month follow-up examination. The ISQ values increased steadily throughout the follow-up period. At the time of implant placement, the range of ISQ values exhibited a mean of 74.33, and by week 26, a mean value of 83.82 was recorded. Based on strict criteria, all 56 implants were considered successfully integrated, resulting in a 6-month survival and success rate of 100.0%. CONCLUSION: This prospective study using an early-loading protocol after 3 weeks of healing demonstrated that titanium implants with the modified SLA surface can achieve and maintain successful tissue integration over a period of at least 6 months. The ISQ method seems feasible to monitor implant stability during the initial wound-healing period.

Implant loading protocols for partially edentulous maxillary posterior sites

PURPOSE: To evaluate early and immediate loading of implants in the posterior maxilla and to investigate whether there is a difference in success rates, survival rates, and peri-implant parameters, including marginal bone level changes. MATERIALS AND METHODS: A comprehensive systematic review of the literature was conducted. The selection of publications reporting on human clinical studies was based on predetermined inclusion criteria and was agreed upon by two reviewers. RESULTS: Twelve papers were identified on early loading (two randomized controlled clinical trials [RCTs] and 10 prospective case series studies). Six papers were found on immediate loading (one RCT, four prospective case series, and one retrospective study). CONCLUSIONS: Under certain circumstances it is possible to successfully load dental implants in the posterior maxilla early or immediately after their placement in selected patients. The success rate appears to be technique sensitive, although no study has directly assessed this. A high degree of primary implant stability (high value of insertion torque) and implant surface characteristics play an important role. It is not possible to draw evidence-based conclusions concerning contraindications, threshold values for implant stability, bone quality and quantity needed, or impact of occlusal loading forces. As for the impact of the surgical technique on implant outcome in different bone densities, no studies prove significant superior results with one technique over another. Well-designed RCTs with a large number of patients are necessary to make early/immediate loading protocols in posterior maxilla evidence based, but ethical and practical considerations may limit the real possibility of such studies in the near future.

Numerical investigation of the mechanical loading of supporting soft tissue for partial dentures

The aim of this research was to study the impact of loading on partial dentures within the supporting soft tissue with respect to different attachment techniques. A finite element model was developed to calculate the stress and strain distribution in this tissue. The model consisted of the left half of a mandible with three remaining teeth that had suffered an atrophy in the anterior region, and a partial denture over the toothless area that was connected at the left mandibular canine using an attachment system. Resulting stress/strain distributions are presented for different load cases using a commercially available prefabricated attachment system.

Effect of oral calcium loading on intact PTH and calcitriol in idiopathic renal calcium stone formers and healthy controls

The calciuric response after an oral calcium load (1000 mg elemental calcium together with a standard breakfast) was studied in 13 healthy male controls and 21 recurrent idiopathic renal calcium stone formers, 12 with hypercalciuria (UCa x V > 7.50 mmol/24 h) and nine with normocalciuria. In controls, serum 1,25(OH)2 vitamin D3 (calcitriol) remained unchanged 6 h after oral calcium load (50.6 +/- 5.1 versus 50.9 +/- 5.0 pg/ml), whereas it tended to increase in hypercalciuric (from 53.6 +/- 3.2 to 60.6 +/- 5.4 pg/ml, P = 0.182) and fell in normocalciuric stone formers (from 45.9 +/- 2.6 to 38.1 +/- 3.3 pg/ml, P = 0.011). The total amount of urinary calcium excreted after OCL was 2.50 +/- 0.20 mmol in controls, 2.27 +/- 0.27 mmol in normocalciuric and 3.62 +/- 0.32 mmol in hypercalciuric stone formers (P = 0.005 versus controls and normocalciuric stone formers respectively); it positively correlated with serum calcitriol 6 h after calcium load (r = 0.392, P = 0.024). Maximum increase in urinary calcium excretion rate, delta Ca-Emax, was inversely related to intact PTH levels in the first 4 h after calcium load, i.e. more pronounced PTH suppression predicted a steeper increase in urinary calcium excretion rate. Twenty-four-hour urine calcium excretion rate was inversely related to the ratio of delta calcitriol/deltaPTHmax after calcium load (r = -0.653, P = 0.0001), indicating that an abnormally up-regulated synthesis of calcitriol and consecutive relative PTH suppression induce hypercalciuria.(ABSTRACT TRUNCATED AT 250 WORDS)

Lithographiebasierte Fertigung keramischer Bauteile

Im Rahmen des EU-Projektes PHOCAM entwickelt das beteiligte Konsortium Anlagen und Materialien für die generative Fertigung keramischer Bauteile auf Basis der Photopolymerisation. Das Kernelement der verwendeten Fertigungsanlagen, der DLP Projektor, erzeugt mittels leistungsstarker LEDs und einem 1080p DMD (Digital Micromirror Device) Bilder mit 1920x1080 Bildpunkten und der Pixelgröße von 40µm, woraus sich die Baufeldgröße von 76,8x43,2mm ergibt. Ein hochviskoser Schlicker, bestehen aus einem gefülltem fotosensitiven Harzsystem, wird von unten durch die gläserne Materialwanne belichtet, wodurch der Schlicker lokal aushärtet (polymerisiert). Auf diese Weise entsteht der Grünling, der in schichtbauweise (Standardschichtdicke von 25-50µm) aufgebaut ist. Im nachfolgenden Sinterprozess werden die Grünlinge zu den fertigen Keramikteilen gebrannt. Als keramisches Basismaterial für den Schlicker wurde vorwiegend Aluminiumoxid in Pulverform verwendet. Mit dem entwickelten System konnten bislang Schlicker mit einem Füllgrad (Keramikanteil) bis zu 50Vol% erfolgreich verarbeitet und zu Keramikteilen mit einer theoretischen Dichte von 99,6% gesintert werden.

Comparison of the biomechanical properties of a ventral cervical intervertebral anchored fusion device with locking plate fixation applied to cadaveric canine cervical spines

OBJECTIVE: To evaluate fixation properties of a new intervertebral anchored fusion device and compare these with ventral locking plate fixation. STUDY DESIGN: In vitro biomechanical evaluation. ANIMALS: Cadaveric canine C4-C7 cervical spines (n = 9). METHODS: Cervical spines were nondestructively loaded with pure moments in a nonconstraining testing apparatus to induce flexion/extension while angular motion was measured. Range of motion (ROM) and neutral zone (NZ) were calculated for (1) intact specimens, (2) specimens after discectomy and fixation with a purpose-built intervertebral fusion cage with integrated ventral fixation, and (3) after removal of the device and fixation with a ventral locking plate. RESULTS: Both fixation techniques resulted in a decrease in ROM and NZ (P < .001) compared with the intact segments. There were no significant differences between the anchored spacer and locking plate fixation. CONCLUSION: An anchored spacer appears to provide similar biomechanical stability to that of locking plate fixation.

Biomechanical evaluation of the stabilizing function of the atlantoaxial ligaments under shear loading: A canine cadaveric study

OBJECTIVES To evaluate the stabilizing function of atlanto-axial ligaments in dogs. STUDY DESIGN Cadaveric biomechanical study. ANIMALS Beagle dog cadavers (n = 10). METHODS The craniocervical region was collected from 10 Beagle cadavers, and the occipito-atlanto-axial region was prepared and freed from the surrounding muscles. Care was taken to preserve integrity of the atlantoaxial ligaments and atlantoaxial joint capsule. The atlanto-occipital joints were blocked with 2 diverging transarticular 1.8 mm positive threaded K-wires. Specimen extremities were embedded in polymethylmethacrylate (PMMA) and mounted on a simulator testing shear load at the atlantoaxial joint. Range of motion (ROM) and neutral zone (NZ) were determined with all ligaments intact, after cutting the apical ligament, both alar ligaments, the transverse ligaments and finally after cutting the dorsal atlantoaxial ligament. RESULTS ROM increased similarly and stepwise during testing. The most significant increase was observed after transection of the alar ligaments. CONCLUSION The alar ligaments seem to be the most important ligamentous structures for stabilization of the atlantoaxial joint under shear load.

Transapical access closure: the TA PLUG device

OBJECTIVES Percutaneous closure of the transapical (TA) access site for large-calibre devices is an unsolved issue. We report the first experimental data on the TA PLUG device for true-percutaneous closure following large apical access for transcatheter aortic valve implantation. METHODS The TA PLUG, a self-sealing full-core closure device, was implanted in an acute animal study in six pigs (60.2 ± 0.7 kg). All the pigs received 100 IU/kg of heparin. The targeted activated clotting time was left to normalize spontaneously. After accessing the left ventricular apex with a 39 French introducer, the closure plug device was delivered with a 33 French over-the-wire system under fluoroscopic guidance into the apex. Time to full haemostasis as well as rate of bleeding was recorded. Self-anchoring properties were assessed by haemodynamic push stress under adrenalin challenge. An additional feasibility study was conducted in four pigs (58.4 ± 1.1 kg) with full surgical exposure of the apex, and assessed device anchoring by pull-force measurements with 0.5 Newton (N) increments. All the animals were electively sacrified. Post-mortem analysis of the heart was performed and the renal embolic index assessed. RESULTS Of six apical closure devices, five were correctly inserted and fully deployed at the first attempt. One became blocked in the delivery system and was placed successfully at the second attempt. In all the animals, complete haemostasis was immediate and no leak was recorded during the 5-h observation period. Neither leak nor any device dislodgement was observed under haemodynamic push stress with repeated left ventricular peak pressure of up to 220 mmHg. In the feasibility study assessing pull-stressing, device migration occurred at a force of 3.3 ± 0.5 N corresponding to 247.5 mmHg. Post-mortem analyses confirmed full expansion of all devices at the intended target. No macroscopic damage was identified at the surrounding myocardium. The renal embolic index was zero. CONCLUSIONS True-percutaneous left ventricular apex closure following large access is feasible with the self-sealing TA PLUG. The device allows for immediate haemostasis and a reliable anchoring in the acute animal setting. This is the first report of a true-percutaneous closure for large-calibre transcatheter aortic valve implantation access.