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Biomedical subjects

George P Teitelbaum

Publications and source records attributed to George P Teitelbaum.

6 recordsLinked to original sources
PubMed2006

A novel technique and new grading scale for the embolization of cerebral vascular malformations.

OBJECTIVE: Effective transarterial embolization of a dural arteriovenous fistula or pial arteriovenous malformation (AVM) requires penetration of a durable occlusive agent into the fistula or AVM nidus. Cyanoacrylate glue often cannot traverse the tortuous vessels that typically supply such malformations, leading to proximal occlusion and recruitment of collateral flow. Other embolic agents, such as polyvinyl alcohol particles, achieve better penetration, but their effects are short lived, often leading to recanalization. The authors sought to overcome these obstacles by developing a technique to enhance glue penetration into the fistula or AVM nidus itself. METHODS: After placing a guide catheter in the proximal feeding artery, a microcatheter is advanced coaxially to its limit. As glue is injected through the microcatheter, a column of 5% dextrose in water (D5W) is pushed manually through the guide catheter lumen to propel the glue forward. This technique has been bench tested in a standard flow model of vascular malformations, using a pump capable of delivering various rates of D5W. It has also been validated in treating 17 patients with cerebral dural arteriovenous fistulae or AVMs, with real-time adjustment of D5W flow according to the extent of glue penetration. RESULTS: In the bench model, the extent of glue penetration, as graded by a new scale of liquid agent embolization proposed by the authors, correlated directly with the rate of D5W flow (P = 0.5, analysis of variance). In vivo, this technique has enhanced the penetration of glue into the fistula or AVM nidus, resulting in longstanding embolization of these malformations. CONCLUSION: Coaxial injection of D5W through the guide catheter can propel cyanoacrylate glue through tortuous feeding arteries and can enhance its penetration into dural fistulae and AVMs, leading to more effective endovascular treatment of these malformations.

Arteriovenous Malformations↗
PubMed2005

Percutaneous spinal interventions.

Interventional neuroradiology procedures of the spine are being performed with increasing frequency. These therapies complement and, in some cases, replace more conventional operations of the vertebral column and its contents. This article surveys the background, present application, and future horizons of several minimally invasive spinal interventions, including vertebroplasty and kyphoplasty, microcatheterization of the cervical epidural space via lumbar puncture for drug delivery, percutaneous intraspinal navigation, and percutaneous spinal fixation.

Diskectomy, Percutaneous↗
PubMed2004

New percutaneously inserted spinal fixation system.

STUDY DESIGN: We describe a new percutaneous minimally invasive spinal fixation system based on pedicle screws and inflatable rods. The rods are inserted in a flexible state and harden following deployment. We test this system in terms of biocompatibility, ferromagnetism, magnetic resonance artifact production, bench top mechanical testing, ease of insertion within cadavers, potential thermal damage to paraspinous muscles in pigs, and long-term device tolerability in sheep. OBJECTIVES: To determine the safety and utility of this system before its use in human subjects. SUMMARY OF BACKGROUND DATA: Composite materials and epoxy compounds have been used safely in a variety of implanted medical devices for years with no signs of systemic toxicity or significant device failures. METHODS: Long-term biocompatibility test of system components was conducted according to International Standards Organization 10993 and Food and Drug Administration Blue Book Memorandum #G95-1 standards. Device components were assessed for magnetic deflection and torque and imaged in a 1.5 Tesla magnetic resonance unit. Full constructs of the system were tested for compression strength, torque, and fatigue per American Society for Testing and Materials F1717 standards. The system was deployed using C-arm fluoroscopic guidance in 11 cadavers and 2 live sheep. Further, the inflatable rods were tested for exothermic damage to paraspinous musculature in 2 pigs. RESULTS: All system components were found to be biocompatible, nonferromagnetic, and produce little magnetic resonance artifact. Compression and torque results for the new system were found to be comparable to standard metallic pedicle screw and rod fixation systems. However, the new system displayed a superior modulus of elasticity relative to standard surgical systems. The new system endured 5 million cycles of repetitive compressions without breakage or significant wear. All cadaver and sheep insertions were performed successfully. Sheep suffered no complications, and minimal blood loss occurred during device insertions. One of the animals killed at 6 months demonstrated no internal organ damage. The self-curing version of polymer used to inflate the flexible rods cured to approximately 53% of its final strength in 90 minutes with maximum external rod temperature of 40.5 C. and no adjacent thermal damage within porcine paraspinous musculature. CONCLUSIONS: The new spinal fixation system is biocompatible, uses a nontoxic polymer, is magnetic resonance compatible, displays favorable biomechanical characteristics, can be easily deployed percutaneously using simple fluoroscopic guidance, is well tolerated in living sheep, caused no muscular thermal damage, and could be used in humans within a reasonable operative time frame. The new system demonstrates the feasibility of percutaneously constructing composite structures in situ within the body.

Animals↗
PubMed2003

Use of a screw-syringe injector for cement delivery during kyphoplasty: technical report.

OBJECTIVE: Percutaneous kyphoplasty is postulated to have several advantages over percutaneous vertebroplasty for the treatment of vertebral compression fractures and is gaining increased popularity. However, cement delivery with the KyphX kit (Kyphon, Inc., Santa Clara, CA), the only commercially available device for percutaneous kyphoplasty, is relatively problematic. This kit uses a series of "bone filler device" (BFD) tubes. Each BFD must be loaded manually with cement, which is then injected into the kyphoplasty cavity by manually depressing an inner stylet. The high profile of the BFD cannulas and their stylets requires frequent repositioning of the image intensifier tube and table. Because each accommodates only a small volume, the BFDs must be exchanged frequently. This delivery method also places the operator's hands directly in the field of radiation. We sought to overcome these limitations. METHODS: Dissatisfied with the shortcomings of the BFDs, we substituted the EZflow screw-syringe injector (Parallax Medical, Mountain View, CA) we use to deliver cement during conventional percutaneous vertebroplasty. This amalgam of the KyphX kit and the screw-syringe injector has been used for kyphoplasty treatment of 26 thoracolumbar compression fractures in 17 patients. RESULTS: The screw-syringe injector allows controlled volumetric delivery of large boluses of high-viscosity cement without having to refill the reservoir. It minimizes radiation exposure and does not require repositioning of the x-ray tubes. It may theoretically allow decompression should cement extrusion occur. Also, it delivers cement to the interstices of bony trabeculae outside the kyphoplasty cavity, thus combining the mechanical benefits of percutaneous kyphoplasty and percutaneous vertebroplasty. CONCLUSION: The use of a screw-syringe injector has several merits over the customary means of cement delivery during kyphoplasty.

Bone Cements↗
PubMed2002

Covered stent-graft repair of the brachiocephalic arteries: technical note.

OBJECTIVE: The use of a covered stent-graft to repair disruptions of the cervical carotid and vertebral arteries is described. This device maintains vessel patency while effectively excluding pseudoaneurysms, arteriovenous fistulae, and other breaches in the integrity of the arterial wall. METHODS: Patient 1 bled from a large rent in the proximal common carotid artery as a result of tumor invasion. Patient 2 developed a vertebral arteriovenous fistula after a stab injury to the neck. Patient 3 developed cerebral infarction and an enlarging pseudoaneurysm of the internal carotid artery, also after a stab wound to the neck. RESULTS: All three patients were treated with the Wallgraft endoprosthesis (Boston Scientific, Watertown, MA). In each case, the vessel wall defect was repaired while antegrade flow through the artery was preserved or restored. No neurological complications occurred as a result of stent-graft deployment. CONCLUSION: Covered stent-grafts offer an alternative to endovascular occlusion of the parent vessel, thereby expanding the therapeutic options for patients with extracranial cerebrovascular disease. These three cases highlight the usefulness and versatility of these devices for endoluminal reconstruction of the brachiocephalic vasculature.

Adult↗