Clinical outcomes of cemented distal femur replacements with all-polyethylene tibial components for oncologic indications.

Background: Endoprosthetic distal femoral replacement (DFR) is a well-established salvage procedure following resection of malignant tumors within the distal femur. Use of an all-polyethylene tibial (APT) component is cost-effective and avoids failure due to locking-mechanism issues and backside wear, but limits modularity and the option for late liner exchange. Due to a paucity of literature we sought to answer three questions: (1) What are the most common modes of implant failure for patients undergoing cemented DFR with APT for oncologic indications? (2) What is the survivorship, rate of all-cause reoperation, and rate of revision for aseptic loosening of these implants? And (3) Is there a difference in implant survivorship or patient demographics between cemented DFRs with APT performed as a primary reconstruction those performed as a revision procedure?

Aim: To assess outcomes of cemented DFRs with APT components used for oncologic indications.

Anteroposterior pelvic radiograph findings correlate with sagittal spinopelvic motion.

It has been well documented in the arthroplasty literature that lumbar degenerative disc disease (DDD) contributes to abnormal spinopelvic motion. However, the relationship between the severity or pattern of hip osteoarthritis (OA) as measured on an anteroposterior (AP) pelvic view and spinopelvic biomechanics has not been well investigated. Therefore, the aim of the study is to examine the association between the severity and pattern of hip OA and spinopelvic motion.

Male-derived copulatory plugs enhance implantation success in female Mus musculus.

Among a wide diversity of sexually reproducing species, male ejaculates coagulate to form what has been termed a copulatory plug. A number of functions have been attributed to copulatory plugs, including the inhibition of female remating and the promotion of ejaculate movement. Here we demonstrate that copulatory plugs also influence the likelihood of implantation, which occurs roughly 4 days after copulation in mice.

Efficacy and safety of Sleeping Beauty transposon-mediated gene transfer in preclinical animal studies.

Sleeping Beauty (SB) transposons have been effective in delivering therapeutic genes to treat certain diseases in mice. Hydrodynamic gene delivery of integrating transposons to 5-20% of the hepatocytes in a mouse results in persistent elevated expression of the therapeutic polypeptides that can be secreted into the blood for activity throughout the animal. An alternative route of delivery is ex vivo transformation with SB transposons of hematopoietic cells, which then can be reintroduced into the animal for treatment of cancer.

Corrosive behaviour of Amplatzer devices in experimental and biological environments.

Purpose: Nitinol, a nickel-titanium alloy, is a valuable material in the construction of interventional endoluminal devices because of its biocompatibility, super elasticity, high resiliency and shape memory. The possibility of nickel toxicity has been raised with devices constructed of Nitinol. Our investigation examines the long-term corrosive behavior of this alloy in experimental and biological environments.

Creation of an intra-atrial communication with a new Amplatzer shunt prosthesis: preliminary results in a swine model.

A nitinol shunt device was applied in six minipigs to create a precise intra-atrial shunt. This self-expanding shunt device consists of two retention disks of 2-8 mm, a 4 mm connecting waist with a 10 mm eccentric hole. It requires a 7 Fr introducer sheath.

Experimental evaluation of a modified Amplatzer duct occluder.

The purpose of this study was to evaluate a new device specifically designed for patent ductus arteriosus (PDA) occlusion based on PDA anatomy. Percutaneous closure of aortopulmonary shunts was attempted in 10 dogs. Shunts were surgically created in the location and orientation of PDA.

Renal artery embolization with diluted hot contrast medium: an experimental study.

Purpose: To evaluate the safety and efficacy of diluted hot contrast medium to embolize the renal arteries in a canine model.

Materials And Methods: Transcatheter embolization was performed in 15 dogs (five dogs in each phase: I, II, and control). The diluted hot contrast medium was heated to 90 degrees C--100 degrees C and 30--60 mL were injected into a renal artery of each dog in phase I (optimization studies) and II (efficacy studies).

Transcatheter closure of membranous ventricular septal defects with a new nitinol prosthesis in a natural swine model.

Transcatheter closure of a membranous ventricular septal defect (MVSD) is much more difficult than closure of other intracardiac defects because of the proximity to the aortic and tricuspid valves and their relatively large size in small children. In this report, transcatheter closure of naturally occurring membranous VSDs was attempted in 12 Yucatan minipigs. The prosthesis is constructed from fine Nitinol wires in the shape of two buttons and a connecting waist filled with polyester fiber.

Injury potential to venous valves from the Amplatz thrombectomy device.

Purpose: To evaluate the acute effects of the Amplatz thrombectomy device (ATD) on peripheral venous valves in a canine model.

Materials And Methods: ATD thrombectomy was performed in 17 veins, and control experiments with use of an 8-F sheath-dilator were performed in four veins. Prethrombectomy ascending venography was performed, followed by device passage across the vein segment.

The nitinol vascular occlusion plug: preliminary experimental evaluation in peripheral veins.

Purpose: To compare the nitinol occlusion plug with standard stainless steel coils for the occlusion of moderate-size peripheral veins.

Materials And Methods: The nitinol plug is a braided multilayered vascular occlusion device filled with thrombogenic polyester fibers. It is self-expanding and can be recaptured into its 6-F introducing sheath for repositioning prior to detachment.

Tracheobronchial metal stents: effects of covering a bronchial ostium in pigs.

Rationale And Objectives: The purpose of this study was to examine the effects of placing a metal stent across a bronchial orifice.

Materials And Methods: Nine pigs were used as test subjects, because the right upper lobe bronchus comes directly off the trachea in these animals. One of three types of metal stents was placed into the trachea of each pig and covered the orifice of the right upper lobe bronchus.

New device for closure of muscular ventricular septal defects in a canine model.

Background: Repair of muscular ventricular septal defects (MVSDs) has always been challenging to the surgeon. Long-term morbidity and mortality are significantly increased if the defects are closed via left ventriculotomy or if they are associated with other complex congenital anomalies. The purpose of this study was to close MVSDs with the Amplatz ventricular septal defect device.

New self-expanding patent foramen ovale occlusion device.

Our purpose was to evaluate a new self-expanding device for closure of the patent foramen ovale (PFO). A transeptal catheter passage through the flap of the fossa ovalis was performed with a transeptal needle inside a catheter, creating a PFO in two minipigs. In an additional five animals, a naturally occurring PFO was found.

A new technique for sizing of atrial septal defects.

This article evaluates a new compliant balloon catheter for sizing of Atrial Septal Defects (ASDs) in vitro and in vivo using X-ray and echo measurements. A phantom consisting of a plastic plate with 17 circular holes varying from 8 to 30 mm was used to determine the accuracy of the measurements. The catheter has a 7 Fr shaft with a double lumen.

Acute and delayed outcomes of mechanical thrombectomy with use of the steerable Amplatz thrombectomy device in a model of subacute inferior vena cava thrombosis.

Purpose: To study the efficacy and delayed outcome of mechanical thrombectomy with the Amplatz thrombectomy device (ATD) in an experimental model of subacute inferior vena cava (IVC) thrombosis.

Materials And Methods: Mechanical thrombectomy was performed in 23 dogs with subacute infrarenal IVC thrombosis (6-15 days old). Heparin was administered during thrombectomy in all procedures (activated clotting time > or = 300 sec).

Transvenous closure of secundum atrial septal defects: preliminary results with a new self-expanding nitinol prosthesis in a swine model.

Background: Our purpose was to evaluate a new prosthesis for percutaneous closure of secundum atrial septal defects (ASDs).

Methods And Results: Percutaneous closure of surgically created fossa ovalis ASD was attempted in 15 minipigs. The mean balloon-stretched ASD diameter was 12.

Repositionable vascular occluder: experimental comparison with standard Gianturco coils.

Purpose: To evaluate the efficacy and recanalization rates of a newly designed vascular occlusion device.

Materials And Methods: The self-expanding vascular occluder was braided from fine nitinol wires and filled with polyester fibers. The device was delivered through a 6-F polyethylene introducing sheath with use of a delivery cable with a microscrew adaptor.

Urokinase-mediated thrombolysis: a dose-response relationship in cats. Work in progress.

A cat model was developed to study thrombolytic agents. The infrarenal aorta was surgically exposed, all side branches were ligated, and both ends of the segment were occluded. After preformed clot was injected into the segment, proximal flow was restored and a distal stenosis was created.

Nonselective and semiselective catheters for renal artery evaluation: experimental study.

Abdominal aortography is widely used for evaluation of potential renal donors and for patients with renal failure or hypertension in whom a renal artery ostial or polar branch stenosis is suspected. It would be desirable to use a catheter that consistently enables good bilateral renal artery and polar branch visualization without opacification of overlying mesenteric vessels. Existing and newly designed catheters were compared to determine the optimal design necessary for these studies.

Thrombogenicity of hydrophilically coated guide wires and catheters.

The thrombogenicities of stainless steel spring guide wires and two hydrophilically coated guide wires were compared. The guide wires were placed in canine femoral arteries for 30 minutes. The guide wires were removed, the thrombi were stripped off, and the clots were weighed.

Retrograde left atrial catheterization.

Catheterization of the left atrium can provide valuable information about both congenital and acquired heart disease. The traditional approach to examination of the left atrium has been the transseptal route, which has occasionally been associated with serious complications. A method of retrograde left atrial catheterization has been developed that is performed with a modified standard catheter.

Prostatic urethra: experimental dilation in dogs.

An animal study was undertaken to develop a balloon dilation technique that could be used in humans to treat the common ailment of benign prostatic hypertrophy. Dogs were used as a model because of the similarities in the prostate between the two species and the ready availability of the canines. A retrograde transurethral approach was used for dilation.