| Cryoprobe for low pressure systems -> Monitor Keywords |
|
|
  Cryoprobe for low pressure systemsRelated Patent Categories: Surgery, Instruments, Cyrogenic Application, Internal ApplicationThe Patent Description & Claims data below is from USPTO Patent Application 20070149959. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTIONS [0001] The inventions described below relate the field of cryoprobes and more specifically to cryoprobes used in surgical procedures. BACKGROUND OF THE INVENTIONS [0002] Cryosurgical probes are used to treat a variety of diseases. The cryosurgical probes quickly freeze diseased body tissue masses, causing the tissue to die after which it will be absorbed by the body, expelled by the body or sloughed off. Cryothermal treatment is currently used to treat prostate cancer and benign prostate disease, breast tumors and breast cancer, liver tumors and cancer, glaucoma and other eye diseases. Cryosurgery is also proposed for the treatment of a number of other diseases. [0003] A variety of cryosurgical instruments, referred to as cryoprobes, cryosurgical ablation devices, and cryostats and cryocoolers, have been available for cryosurgery. The preferred device uses Joule-Thomson cooling in devices known as Joule-Thomson cryostats. These devices take advantage of the fact that most gases, when rapidly expanded, become extremely cold. In these devices, a high pressure gas such as gaseous argon or gaseous nitrogen is expanded through a nozzle inside a small cylindrical sheath made of steel, and the Joule-Thomson expansion cools the steel sheath to sub-freezing cryogenic temperature very rapidly. [0004] Present cryoprobes utilizing Joule-Thomson systems have inherent disadvantages such as inefficient heat transfer, the possible occurrence of vapor lock and excessive use of cryogen. As a result, these systems require use of large quantities of gasses under high pressure and high flow rates, in part, to prevent vapor lock. Use of high-pressure gasses increases the overall costs of cryoprobes. This is due to the higher costs of materials required for use with systems utilizing high-pressure gases, the high cost associated with keeping source gases themselves at higher pressures and the large quantities of cryogen required for use with these systems. What is needed is a cryoprobe system requiring low pressure with low fluid volume and flow rates that avoids vapor lock and reduces the quantities of cryogen required by using cryogen more efficiently. SUMMARY [0005] The devices and methods described below provide for the cryo-ablation of a mass of targeted tissue. The devices include a probe with structures that permit the surgeon to secure and form an ice mass of a suspect mass or tumor. The probe is provided with a rigid tube and a sharp distal segment. To secure the tumor to the probe, the surgeon pierces the tumor with the distal segment. Inlet tubing extending within the rigid tube directs coolant to the distal tip to cool the tip. A helical-shaped baffle comprising a heating element is provided in the distal section of the cryoprobe to create turbulent fluid and improve heat transfer. Since the baffle comprises a heating element, it can be further used in rapid freezing and warming cycles directed at targeted tissue masses. BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1 illustrates a cryoprobe. [0007] FIG. 2 shows a partial sectional side view of the distal end portion of the cryoprobe. [0008] FIG. 3 shows a partial isometric sectional view of the distal end portion of the cryoprobe. [0009] FIG. 4 illustrates a cryoprobe with a baffle having a cross-shaped cross-section disposed about the inlet tube. [0010] FIG. 5 illustrates a cryoprobe with a baffle having a sprocket cross-section disposed about the inlet tube. [0011] FIG. 7 depicts a cryoprobe having an outer tube with a grooved inner diameter. [0012] FIG. 8 illustrates a cryoprobe with a baffle comprising a tubular-shaped insulator and a heating element wound about the distal section of the inlet tube. DETAILED DESCRIPTION OF THE INVENTIONS [0013] FIG. 1 illustrates a cryoprobe 1. The cryoprobe uses liquid nitrogen cooling to create a cooled region at the distal end 2. This cooled region adheres to a targeted lesion or tumor and creates an ice mass from the targeted tissue. The cryoprobe comprises a long, slender yet rigid outer tube 3. A short rigid penetrating segment 4 extends distally from the distal end of the rigid tube, and a suitable handle 5 is mounted on the proximal end of the tube. The handle is placed in fluid communication with a console 6 and the console is place in electrical communication with a power source 7 and fluid communication with a cryogen source 8. The console has a control system that is able to regulate use of power and the flow of cryogen to the cryoprobe. [0014] FIG. 2 shows a partial sectional side view of the distal end portion of the cryoprobe 1 while FIG. 3 shows a partial isometric sectional view of the distal end portion of the cryoprobe 1. The cryoprobe 1 comprises a rigid outer tube 3 and an inner coolant inlet tube 9. A short rigid penetrating segment 10 extends distally from the distal end of the outer tube 3. The coolant inlet 9 tube passes through the outer tube 3, extending to the distal end of the outer tube 3, terminating just proximal of the distal tip of the penetrating segment leaving a chamber 11 between the distal end of the inlet tube 9 and the proximal end of the penetrating element 4. The inlet tube may terminate by merely a straight cut or have a small nozzle of smaller internal diameter than the immediately upstream portion of the inlet tube. The outer tube 3 is made from stainless steel. However, the outer tube may also be manufactured from aluminum, brass, ceramics or MRI compatible materials. The inlet tube 9 is made from a polyetheretherketon (PEEK) or other lower thermally conductive material having a pressure and temperature capability sufficient for the pressures and temperatures anticipated for the particular application. Use of lower thermally conductive materials for the inlet tube 9 reduces the amount of cryogen required by the cryoprobe 1. Suitable inlet tube 9 material includes fluoropolymer tubing (FEP), Teflon.RTM., polyimide and polyurethane. [0015] The outer tube 3 has an outer diameter of about 2.7 mm, an internal diameter of about 2.4 mm, and a length of about 40 mm. The inlet tube 9 has an outer diameter of about 0.76 mm and an inner diameter of about 0.64 mm. These dimensions may vary depending on the materials used and the application for the cryoprobe. The penetrating segment 4 comprises a sharp distal tip 12. As can be seen from the cross section, the sharp distal tip is solid and adapted for piercing through a tumor. The length of the penetrating segment is chosen to be approximately the same size as the target tissue mass to be sampled. This penetrating segment is forced into a lesion or tumor. An annular cavity 13 or lumen is created by the outer surface of the inlet tube and the inner surface of the rigid outer tube 3. The liquid exiting the orifice of the inlet tube 9 counter-flows along the annular cavity and is exhausted from the probe to a suitable point far removed from the probe. [0016] A helical-shaped baffle 14 comprising a heating element 15 is disposed about the outer surface of a distal portion of the inlet tube and extends proximally about 18 mm from the distal end of the inlet tube. However, the baffle 14 may extend up to about 40 mm proximal to the distal end of the inlet tube 9. The helical-shaped baffle is adapted to produce turbulent fluid flow in fluid flowing past the outer surface of the inlet tube. The baffle 14 improves heat transfer by creating turbulent flow and forcing the cryogen outward to come in contact with the inner diameter surface of the outer wall in the distal section of the cryoprobe. The baffle 14 can comprise a separate extrusion, a machined part or a preformed wire. The baffle 14 may be formed by winding the inlet tube 9 about the longitudinal axis or a second helical-shaped baffle may also be provided in the distal section of the probe. [0017] The heating element 15 and the baffle 14 may be unitary and made from the same material or the heating element 15 may be separate from the baffle and made from a different material. When the heating element and baffle 14 are unitary the baffle 14 is manufactured from a material capable of being heated when placed in electrical communication with a power source. In FIG. 2, the baffle 14 is manufactured from nichrome wire placed in electrical communication with a power source. Thus, the baffle 14 provides both turbulent fluid flow while also able to function as a heating element. In FIG. 3, the baffle 14 is a helical structure machined from brass and the heating element 15 is a separate material disposed within the baffle. The temperature of the heating element is regulated by the console. A thermocouple 16 is disposed on the distal section of the cryoprobe 1 to measure temperatures at the probe tip. In FIG. 6, the baffle [0018] FIGS. 4-6 illustrate cross-sections of various cryoprobes 1 having an outer tube 3 with baffles 14 comprising a heating element having differing configurations and disposed about the outer surface of the inlet tube. FIG. 4 illustrates a cryoprobe with a baffle having a cross-shaped 17 cross-section disposed about the inlet tube. FIG. 5 illustrates a cryoprobe with a baffle having a sprocket cross-section 18 disposed about the inlet tube. In FIG. 6, the baffle comprises a cross-section with opposing arcuate trapezoidal sections 19 disposed about the inlet tube. The baffles in FIGS. 4-6 improve heat transfer by creating turbulent flow while forcing the cryogen outward towards the inner diameter surface of the outer wall in the distal section of the cryoprobe where the non-target body tissue can further act as a heat sink. [0019] FIG. 7 depicts a cryoprobe 1 having an outer tube 3 with a grooved inner diameter 20. The cryoprobe comprises an outer 3 tube and an inner coolant inlet tube 9. A short rigid penetrating segment 4 extends distally from the distal end of the outer tube. The coolant inlet tube passes through the outer tube, extending to the distal end of the outer tube, terminating just proximal of the distal tip of the penetrating segment 4 leaving a chamber between 11 the distal end of the inlet tube 9 and the proximal end of the penetrating element 4. Continue reading... Full patent description for Cryoprobe for low pressure systems Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Cryoprobe for low pressure systems patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Cryoprobe for low pressure systems or other areas of interest. ### Previous Patent Application: Surgical instrument positioning system and method of use Next Patent Application: Cryoprobe with exhaust heater Industry Class: Surgery ### FreshPatents.com Support Thank you for viewing the Cryoprobe for low pressure systems patent info. IP-related news and info Results in 0.58647 seconds Other interesting Feshpatents.com categories: Medical: Surgery , Surgery(2) , Surgery(3) , Drug , Drug(2) , Prosthesis , Dentistry |
||
