Method and apparatus for remodeling/profiling a tissue lumen, particularly in the urethral lumen in the prostate gland

Abstract

Apparatus for tissue lumen (such as urethra) remodeling includes an elongated shaft and at least one expandable structure on a distal end of the shaft. At least one desiccator or energy emitter is carried by the structure and operable to define a support structure in lumen tissue that resists lumen closure. Apparatus is also disclosed for identifying tissue or developing a profile of tissue along the lumen based at least in part on an electrical characteristic of the tissue. Methods of remodeling and profiling are also disclosed.

What is claimed is: 
     
         1 . Apparatus for remodeling a tissue lumen comprising:
 an elongated shaft having proximal and distal end portions;   at least one expandable structure located at the distal end portion and being movable between a retracted position for insertion into and withdrawal from the lumen and an expanded position for enlarging a selected portion of the lumen;   at least one tissue desiccator carried on the expandable structure in a preselected configuration for contacting lumen tissue when the expandable member is expanded;   the preselected configuration being operable to defining in the lumen tissue a support structure of desiccated tissue that resists closure of the lumen.   
     
     
         2 . The apparatus of  claim 1  in which the expandable structure includes at least one balloon, basket, cage or open framework. 
     
     
         3 . The apparatus of  claim 1  or  2  wherein the expandable structure comprises a balloon. 
     
     
         4 . The apparatus of any one of  claims 1 - 3  in which the expandable structure has a plurality of regions that expand to different cross-sectional sizes. 
     
     
         5 . The apparatus of  claim 4  wherein the expandable structure includes at least a proximal region, a distal region and an intermediate region therebetween, and when expanded, the intermediate region has a larger cross-sectional size that the proximal and distal regions. 
     
     
         6 . The apparatus of any one of  claims 1 - 5  wherein the expandable structure has a length sufficient to extend substantially between the urinary sphincter and bladder neck and through the prostate gland of a male urinary tract. 
     
     
         7 . The apparatus of any one of  claims 1 - 6  wherein at least a portion of the expandable structure, when expanded, has a cross-sectional size sufficient to substantially enlarge the cross-sectional size of the urinary tract through a prostate gland. 
     
     
         8 . The apparatus of any one of  claims 1 - 7  wherein the expandable structure comprises an inflatable balloon that has a proximal end portion, a distal end portion and an intermediate portion;
 the balloon having a length sufficient to extend through a male urinary tract substantially between the urinary sphincter and bladder neck such that the proximal portion is located in the vicinity of the sphincter and the distal portion is located in the vicinity of the bladder neck and the intermediate portion is located within the prostate gland, the intermediate portion of the balloon when expanded having a cross-sectional size sufficiently large to enlarge the cross-sectional size of the urethra and the proximal and distal portions having a smaller expanded cross-sectional size than the intermediate portion. 
 
     
     
         9 . The apparatus of any one of  claims 1 - 2  and  4 - 7  wherein the expandable member comprises an open framework. 
     
     
         10 . The apparatus of any one of the above  claims 1 - 9  in which the at least one tissue desiccator comprises a plurality of desiccators spaced apart on the expandable structure. 
     
     
         11 . The apparatus of any one of the above  claims 1 - 10  in which the at least one tissue desiccator comprises at least one and preferably a plurality of electrodes. 
     
     
         12 . The apparatus of any one of the above  claims 1 - 11  in which the at least one tissue desiccator comprises a plurality of electrode groups, each group including a plurality of electrodes and each of the groups being spaced apart from other of said groups. 
     
     
         13 . The apparatus of  claim 11  or  12  in which at least two electrodes of each desiccator or group are connectable to the opposite poles of an rf electrical generator. 
     
     
         14 . The apparatus of any one of  claims 1 - 13  wherein each desiccator comprises at least two spaced electrodes connectable to opposite poles of an rf energy generator. 
     
     
         15 . The apparatus of  claim 11  or  14  wherein each electrode comprises an elongated or a point electrode. 
     
     
         16 . The apparatus of any of the above  claims 1 - 15  further comprising a plurality of electrode pairs at spaced apart locations on the expandable structure, each pair comprising two spaced electrode rings configured to contact tissue upon expansion of the expandable structure, the electrodes of each pair being connectable to opposite poles of an rf generator to form, when energized, an annular ring or hoop of desiccated tissue in the lumen, whereby a plurality of spaced apart annular desiccation tissue rings may be formed in the lumen to support it in an open condition. 
     
     
         17 . The apparatus of any one of the above  claims 1 - 16  wherein the at least one desiccator is extensible so as to enlarge as the expandable structure is expanded. 
     
     
         18 . The apparatus of any one of  claims 1 - 17  further including a monitor that senses an electrical characteristic of lumen tissue surrounding at least one of the desiccators. 
     
     
         19 . The apparatus of  claim 18  in which the electrical characteristic is impedance or resistance or conductivity. 
     
     
         20 . The apparatus of  claim 18  or  19  wherein the monitor generates information based at least in part on the electrical characteristic sensed for determining different types of tissue surrounding the desiccator. 
     
     
         21 . The apparatus of any one of  claims 1 - 20  further comprising a shield selectively movable to separate at least one desiccator from lumen tissue to shield such tissue from desiccation. 
     
     
         22 . The apparatus of  claim 21  wherein the shield comprises a sheath axially movable along and over the shaft. 
     
     
         23 . The apparatus of any one of  claims 1 - 22  further comprising an elongated hollow sheath having a lumen for slidably receiving the elongated shaft and at least one sensing station on the sheath for contacting lumen tissue and sensing an electrical characteristic of tissue therearound. 
     
     
         24 . The apparatus of  claim 23  further comprising a plurality of sensing stations disposed along the sheath. 
     
     
         25 . The apparatus of  claim 23  comprising a plurality of dessicators spaced apart along the shaft and the sheath including a plurality of sensing stations spaced apart along the sheath, the sensing stations being respectively spaced apart substantially the same distance that the desiccators are spaced apart. 
     
     
         26 . The apparatus of any one of  claims 23 - 25  further comprising a monitor that senses an electrical characteristic of tissue surrounding each of the sensing stations. 
     
     
         27 . The apparatus of  claim 26  wherein the electrical characteristic sensed includes resistance, impedance or conductivity. 
     
     
         28 . The apparatus of claim of any one of  claims 18 - 20  and  26 - 27  wherein the monitor provides user information to distinguish tissue types based at least in part on the sensed electrical characteristic. 
     
     
         29 . The apparatus of any one of the above  claims 1 - 17  comprising a monitor for monitoring an electrical characteristic of lumen tissue surrounding at least one desiccator and generating a tissue profile of the electrical characteristic. 
     
     
         30 . A method for remodeling a tissue lumen comprising:
 enlarging a selected length of the lumen; and   desiccating tissue of and surrounding the lumen while it is enlarged, in a predetermined pattern that resists closure of the lumen.   
     
     
         31 . The method of  claim 30  in which the lumen is enlarged by expanding an expandable member within the selected length of lumen. 
     
     
         32 . The method of any one of  claims 30 - 31  in which the lumen tissue is desiccated by heating it. 
     
     
         33 . The method of any one  claims 30 - 32  comprising inserting an expandable member into the selected length of lumen, the expandable member carrying at least one electrode defining the predetermined pattern, and expanding the expandable member to enlarge the lumen and contact lumen tissue with the at least one electrode, and energizing the at least one electrode to heat the lumen tissue in contact with the at least one electrode. 
     
     
         34 . The method of any one of  claims 30 - 33  in which the selected length of tissue lumen includes the lumen of a urethra within a prostate gland. 
     
     
         35 . The method of any one of  claims 30 - 34  including generating a profile of an electrical characteristic of tissue along the urinary tract. 
     
     
         36 . The method of  claim 35  in which the electrical characteristic includes impedance, resistance or conductivity. 
     
     
         37 . The method of  claim 35  or  36  in which the profile is generated before the enlarging and desiccating. 
     
     
         38 . A method of creating a profile of an electrical characteristic of tissue along the urinary tract of a human comprising contacting tissue of the urinary tract with at least one sensor at spaced locations along the urinary tract and sensing the electrical characteristic at such locations. 
     
     
         39 . The method of  claim 38  in which the sensor comprises an electrode. 
     
     
         40 . The method of  claim 38  or  39  in which the sensor comprises two spaced electrodes, and the method includes applying a voltage between the electrodes and sensing impedance, resistance, conductivity, voltage and/or current flow between the electrodes. 
     
     
         41 . The method of any one of  claims 38 - 40  including inserting a tool into the urethra, the tool comprising a plurality of spaced apart electrode pairs, contacting urethral tissue with the spaced electrode pairs and sensing a electrical characteristic of tissue associated with each of the plurality of electrode pairs. 
     
     
         42 . The method of any of  claims 38 - 41  including distinguishing prostate tissue based at least in part on such sensed electrical characteristic. 
     
     
         43 . The method of any of  claims 38 - 42  including distinguishing urinary sphincter tissue from prostate tissue based at least in part on the sensed electrical characteristic. 
     
     
         44 . The method of any of  claims 38 - 42  including distinguishing the bladder neck tissue from prostate tissue based at least in part on the sensed electrical characteristic. 
     
     
         45 . The method of any of  claims 41 - 45  in which the tool comprises a sheath and the method includes allowing the sheath to remain in the urinary sphincter as least temporarily to protect the sphincter for substantial damage during desiccation of prostate tissue. 
     
     
         46 . The method of any one of the above  claims 30 - 45  employing apparatus of any of  claims 1 - 29 . 
     
     
         47 . Apparatus for developing a tissue profile along a bodily lumen, the apparatus comprising:
 an elongated shaft sized for insertion into the lumen;   a plurality of electrodes at spaced apart locations along the shaft for contacting tissue along the lumen;   a monitor in electrical communication with electrodes for monitoring an electrical characteristic of tissue in contact with the electrode, the monitor including a user interface for communicating information to the user about the electrical characteristic sensed along the lumen.   
     
     
         48 . The apparatus of  claim 47  wherein the monitor generates a tissue profile of the electrical characteristic along the lumen. 
     
     
         49 . The apparatus of any one of  claims 47 - 48  wherein the electrical characteristic sensed includes one or more of resistance, impedance, conductivity, current flow and voltage. 
     
     
         50 . The apparatus of any one of  claims 47 - 49  wherein the user interface includes a meter, gauge, graph, electronic display, or printer. 
     
     
         51 . The apparatus of any one of  claims 47 - 50  including a generator for providing a sensing energy level to the electrodes for determining an electrical characteristic of tissue along the lumen. 
     
     
         52 . The apparatus of any one of  claims 47 - 51  including a generator for generating a desiccation energy level to the electrodes for desiccating tissue proximal to the electrodes. 
     
     
         53 . The apparatus of any one of  claims 47 - 52  further comprising an expandable structure carried on a distal end of the shaft. 
     
     
         54 . The apparatus of any one of  claims 47 - 53  wherein the bodily lumen is a urethra and the electrodes are located along a portion of the shaft that, when inserted into the urethra, would extend substantially between the urethral sphincter and the bladder neck. 
     
     
         55 . The apparatus of any one of  claims 47 - 54  comprising a plurality of electrode pairs at spaced locations along the shaft. 
     
     
         56 . The apparatus of  claim 55  further comprising a monitor including a generator for applying a first or sensing energy between the electrodes of each pair and sensing an electrical characteristic of tissue proximal to each electrode pair. 
     
     
         57 . The apparatus of  claim 56  in which the generator is operable to generate a second and higher energy between the electrodes of each pair to desiccate tissue in proximity thereto.