809 results about "Thermal damage" patented technology

Methods and systems for heating a body tissue region adjacent a body lumen using selective accumulation of energy without knowledge of tissue topography. Methods include positioning an energy delivery portion of a catheter within the lumen adjacent the body tissue region, determining a pulse characteristic in response to a thermal property of a first tissue type and applying pulsed energy with the characteristic to treat a second tissue type within the region by drawing heat from the first tissue at a rate that inhibits thermal damage to the first tissue while building-up heat in the second tissue. Systems include a catheter body having an energy delivery portion processor configured to control a pulse characteristic of pulsed energy to therapeutically treat the second tissue by drawing heat from the first tissue at a rate that inhibits thermal damage to the first tissue while building-up heat in the second tissue.

Selective occlusion of a blood vessel is achieved by selectively damaging endothelial cells at a target location in the blood vessel, resulting in the formation of a fibrin clot proximate to the damaged endothelial cells. Additional fibrinogen can then be introduced into the blood vessel if occlusion is not achieved, as the fibrinogen is converted to fibrin by enzymes released by the exposed thrombogenic tissue and activated platelets. Endothelial cells are selectively damaged using thermal effects induced by ultrasound, by mechanical effects induced by ultrasound, or by mechanical effects produced by a tool introduced into the blood vessel (such as a catheter-based tool). A particularly preferred technique for selectively damaging endothelial cells involves introducing an ultrasound activatable agent into the blood vessel, and causing cavitation in that agent using pulses of high-intensity focused ultrasound having a duration insufficient to induce thermal damage in adjacent perivascular tissue.

Body lumens such as blood vessels are selectively occluded by applying radiofrequency voltage to a vaso-occlusive coil (100) at the target site (TS) and generating a thermal reaction to induce fibrogenic occlusion of the blood vessel (BV) around the vaso-occlusive coil. The radiofrequency current is usually sufficient to induce thermal damage to the luminal wall and to coagulate the surrounding blood, thereby initiating clotting and subsequent fibrosis to permanently occlude the lumen. The invention also includes a method for endoluminally deploying the vaso-occlusive coil and preventing migration of the coil from of the target site.

An electrosurgical electrode assembly and method utilizing the same are disclosed capable of controlling or limiting the current per arc in real-time during an electrosurgical procedure. The conductive electrosurgical electrode is configured for being connected to an electrosurgical generator system and has a non-conductive, porous ceramic coating that “pinches” or splits the arc current generated by the electrosurgical generator system into the smaller diameter pores of the coating, effectively keeping the same current and voltage, but creating several smaller diameter arcs from one larger diameter arc. This has the effect of separating the arc current, effectively increasing the current frequency, resulting in a finer cut or other surgical effect. That is, the non-conductive, porous ceramic coating enables a low frequency current to achieve surgical results indicative of a high frequency current, while minimizing or preventing thermal damage to adjacent tissue.

A method of depositing various materials onto heat-sensitive targets. Heat-sensitive targets are generally defined as targets that have thermal damage thresholds that are lower than the temperature required to process a deposited material. The invention uses precursor solutions and / or particle or colloidal suspensions, along with optional pre-deposition treatment and / or post-deposition treatment to lower the laser power required to drive the deposit to its final state. The present invention uses Maskless Mesoscale Material Deposition (M3D™) to perform direct deposition of material onto the target in a precise, highly localized fashion. Features with linewidths as small as 4 microns may be deposited, with little or no material waste. A laser is preferably used to heat the material to process it to obtain the desired state, for example by chemical decomposition, sintering, polymerization, and the like. This laser processing may be performed in an ambient environment with laser powers of less than 100 milliwatts.

An apparatus and method for creating drug-filled pockets within muscle tissue, such as myocardium of the heart for increasing angiogenesis. More particularly, the apparatus has an excising assembly with a dilator tip for penetrating and advancing through the surface and body of a muscle or organ, such as the heart. Preferably, the dilator tip has a low level laser optical fiber emission to ease the passage of the excising assembly and provide thermal damage which also stimulates angiogenesis. More preferably, the dilator tip also disperses a pharmacologically active substance as the apparatus is passed through the tissue and / or creates pockets. The excising assembly is connected to a hand-held control device from which the operator pushes a switch to activate a punching mechanism within the excising assembly. The punching mechanism cuts a discrete piece of muscle tissue and traps it within the excising assembly leaving a pocket in the remaining muscle tissue. The excising assembly may also optionally release a bolus of the pharmacologically active substance into the pocket so created. Most preferably, there is a timing mechanism to measure the contraction of the heart, and the timing mechanism is synchronized with the operator's switch on the hand-held device to ensure that the punching occurs at maximum contraction of systole. A measurement guide determines how much excised tissue is trapped in the reservoir of the excising assembly. At a threshold level of filling, the surgeon will remove the excising assembly from the hand-held control device and open the punching mechanism for release of tissue. More preferably, the threshold level of filling will automatically turn off the switch to the punching mechanism to indicate to the surgeon the need to empty the excising assembly of tissue.