Abstract:
A reusable temperature sensing probe assembly comprises a temperature sensor strip extending from one end of a handle. The temperature sensor strip carries at least one temperature sensor for measuring temperature within a body cavity of a person, such as the rectum. The handle/temperature sensor strip is reversibly positionable within a unitary balloon/sleeve assembly comprised of a balloon portion and a sleeve portion. The balloon portion is comprised of a first interior space configured to hold the temperature sensor stip and a second interior space separate from the first interior space that is configured for inflation. An inflation tube has one portion sealed within the second interior space of the balloon portion and a second portion which extends through the sleeve portion for connection to a fluid source.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]     This application claims the benefit of Provisional Application No. 60/558,746 filed Apr. 1, 2004 for RECTAL PROBE WITH DISPOSABLE BALLOON ASSEMBLY”. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a temperature sensing probe for sensing rectal temperature of a patient. In particular, the present invention relates to a temperature sensing probe comprising a reusable handle and sensor array with a disposable balloon/sleeve assembly.  
         [0003]     The prostate gland is a complex, chestnut-shaped organ which encircles the urethra immediately below the bladder and lies immediately adjacent the rectum. This relatively small organ, which is the most frequently diseased of all internal organs, is the site of a common affliction among older men, benign prostatic hyperplasia (BPH), as well as a more serious affliction, cancer. BPH is a non-malignant, bilateral nodular tumorous expansion of prostate tissue occurring mainly in the transition zone of the prostate. Left untreated, BPH causes obstruction of the urethra which usually results in increased urinary frequency, urgency, incontinence, nocturia and slow or interrupted urinary stream. BPH may also result in more severe complications, such as urinary tract infection, acute urinary retention, hydronephrosis and uraemia.  
         [0004]     A fairly recent treatment method for BPH involves microwave thermal therapy, in which microwave energy is employed to elevate the temperature of tissue surrounding the prostatic urethra above about 45° C., thereby thermally damaging the tumorous BPH tissue. Delivery of microwave energy to tumorous prostatic tissue is generally accomplished by a microwave antenna-containing applicator, which is positioned within a body cavity adjacent the prostate gland. The microwave antenna, when energized, heats adjacent tissue due to molecular excitation and generates a radiation pattern which encompasses and necroses the tumorous prostatic tissue. The necrosed intraprostatic tissue is subsequently reabsorbed by the body, thereby relieving an individual from the symptoms of BPH.  
         [0005]     One type of thermal therapy treatment of BPH is transurethral microwave thermotherapy. This method of treatment positions a Foley-type catheter containing a microwave antenna within the urethra adjacent to the prostate gland. The microwave antenna is energized to heat a selected volume of tumorous prostatic tissue surrounding the urethra to about 45° C. for a time sufficient to necrose the selected volume of tissue.  
         [0006]     Due to the relatively close proximity of the rectum to the urethra, it is critically important in the course of transurethral microwave thermotherapy that the temperature of the rectum is maintained below a threshold temperature. Rectal temperatures greater than the threshold may cause damage to the rectum.  
         [0007]     Typically, the temperature of rectal tissue adjacent the prostate is measured and monitored with a rectal temperature sensing probe. The probe supports one or more temperature sensing elements against a wall of the rectum adjacent to the prostate to provide the physician with essential information for controlling the location and degree of heat induced in the prostate. In providing a rectal probe to measure the temperature of rectal tissue adjacent the prostate, it is desirable to maintain the position of a temperature sensing device supported by the probe directly adjacent to the rectal wall to provide optimally accurate temperature readings. There is a continuing need for an improved rectal temperature sensing probe.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention is a temperature sensing probe assembly comprising a reusable temperature sensor/handle assembly and a balloon/sleeve assembly. The temperature sensor/handle assembly is comprised of a handle having a length, a width, a first end and a second end, and a temperature sensor strip carried by the handle and extending from the first end of the handle. The temperature sensor strip comprises a temperature sensor spaced from the first end. The temperature sensor is configured for connection to a thermometry device. The balloon/sleeve assembly comprises opposing first and second polymeric layers configured to define a balloon portion and a sleeve portion. The balloon portion further comprising a first interior space in communication with an interior space of the sleeve portion, and a second interior space isolated from the first interior space and the interior space of the sleeve portion. A first tube portion of an inflation tube is sealingly connected within the second interior space of the balloon portion and is configured with an inflation port. A second tube portion of the inflation tube extends through the sleeve portion and is configured for connection to a fluid source. The handle is reversibly positionable within the sleeve portion and the temperature sensor strip is reversibly positionable within the first interior space of the balloon portion. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a top view of the rectal temperature sensing probe of the present invention.  
         [0010]      FIG. 2  is a bottom view of the rectal temperature sensing probe of  FIG. 1 .  
         [0011]      FIG. 3  is a bottom exploded view of the rectal temperature sensing probe of  FIG. 1 .  
         [0012]      FIG. 4  is an enlarged perspective view of the reusable probe handle and temperature sensor array of the rectal temperature sensing probe of the present invention.  
         [0013]      FIG. 5  is an exploded perspective view of the single use balloon/sleeve assembly of the rectal temperature sensing probe of the present invention.  
         [0014]      FIG. 6  is a cross-sectional view of the balloon/sleeve assembly of the present invention taken along line  6 - 6  of  FIG. 1 .  
         [0015]      FIG. 7  is a top view of the rectal temperature sensing probe of the present invention with the temperature sensing array partially inserted in a guide tube of the balloon/sleeve assembly.  
     
    
       [0016]     While the above-identified drawing figures set forth preferred embodiments of the invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the present invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this invention. It should be specifically noted that the figures have not been drawn to scale, as it has been necessary to enlarge certain portions for clarity.  
       DETAILED DESCRIPTION  
       [0017]      FIG. 1  is a top view of the rectal temperature sensing probe  10  of the present invention. As shown in  FIG. 1 , probe  10  is generally comprised of a probe handle  12  and a balloon/sleeve assembly  14 . The probe handle  12  includes a handle body  16  and a temperature sensor array  18  which carries a plurality of longitudinally spaced temperature sensors  20 . In one embodiment, handle  16  is preferably formed of silicone in a molding process that captures a sensor cable  22 , which is electrically connected to sensor array  18 . Handle body  16  has a length of about 6.0 inches to about 6.5 inches and a nominal diameter of about 0.5 inches.  
         [0018]     Temperature sensor array  18  is comprised of the plurality of temperature sensors  20  bonded to a flexible circuit which is housed within a protective strip. A suitable temperature sensor array is fully described in U.S. Pat. No. 5,792,070, which is incorporated herein by reference. In one embodiment, temperature sensor array  18  extends from a proximal end  24  of handle body  16 , with temperature sensor  20 A positioned approximately 1.75 inches to about 2.15 inches from proximal end  24 . Temperature sensor array  18  has a length extending from proximal end  24  of handle body  16  of about 4.4 inches to about 4.6 inches. Temperature sensors  20  are oriented and spaced to sense a temperature of a wall of the rectum facing the prostate when probe  10  is properly positioned within the rectum of a patient undergoing a heat treatment of the prostate. Sensor cable  22  is configured for connection to a rectal thermometry unit to transmit a signal representative of the sensed wall temperature, as is fully described in the aforementioned U.S. Pat. No. 5,792,070.  
         [0019]     The balloon/sleeve assembly  14  includes a balloon portion  26 , which holds and carries temperature sensor array  18 , and a sleeve portion  28 , which enshrouds a portion of the handle body  16 . The balloon/sleeve assembly  14  is designed to be a disposable unit that can be separated from the probe handle  12  after use of probe  10 . The balloon portion  26  and sleeve portion  28  are formed from layers of a flexible, biocompatible polymer, such as polyurethane, in a manner to be more fully described. As shown in  FIG. 1 , the balloon portion  26  and sleeve portion  28  may be transparent to enable verification of a proper positioning of the temperature sensor array  18  within the balloon portion  26 . The balloon portion  26  is formed with a central channel  30 , which positions temperature sensor array  18  in a proper orientation relative to an outer surface  32  of the balloon portion  26 . With temperature sensor array  18  properly positioned within channel  30 , proximal end  24  of the probe handle  12  lies generally adjacent to a waist  34  of the balloon portion  26 , which is a point of transition from the balloon portion  26  to the sleeve portion  28 . Balloon portion  26  is dimensioned to fit within the rectum of a patient and engage the rectal wall when the balloon portion  26  is inflated, with the proximal end  24  of the probe handle  12  remaining external to the rectum. An inflation tube  36 , which is in communication with a fluid source, extends along the probe handle  12  and into the balloon portion  26  to inflate the balloon portion  26 . The sleeve portion  28  is sized to permit easy assembly and disassembly of the probe handle  12  from the balloon/sleeve assembly  14  and to cover the handle body  16  when probe  10  is in use.  
         [0020]      FIG. 2  is a bottom view of the probe  10  of  FIG. 1 . As shown in  FIG. 2 , inflation tube  36  extends along the probe handle body  16  within a channel  38  formed relative to a bottom surface  40  of handle body  16 . Inflation tube  36  extends to a tip  42  of balloon portion  26  and is configured with a bulbous end  44  in contact with the tip  42 . The bulbous end  44  is fixed relative to the inflation tube  36  to provide a blunt surface in contact with an inner surface of balloon portion  26  for the safety of the patient in the event tip  42  contacts patient tissues. In one embodiment, inflation tube  36  is provided with a plurality of openings  46  within balloon portion  26  for the introduction of an inflation medium. The plurality of openings  46  are oriented on opposite sides of inflation tube  36  to provide flexibility in a preferred plane to allow for anterior rectal wall contact of temperature sensors  20  while maintaining column strength/flexural rigidity of inflation tube  36  sufficient for insertion of balloon portion  26  into the rectum. For increased flexibility at waist  36 , the size of openings  46  at or near to waist  36  may increased or elongated.  
         [0021]     Channel  38  of handle body  16  is dimensioned to secure inflation tube  36  relative to handle body  16  when inflation tube  36  is positioned therein. Accordingly, the elongated opening  48  of channel  38  has a width that is less than an outer diameter of inflation tube  36  when handle body  16  is unstressed. Owing to the flexible characteristics of the silicone material forming handle body  16 , the opening  48 , however, can yield sufficiently to permit the inflation tube  36  to be press fit into and removed from channel  38  with an application of sufficient force. In the absence of such force, the edges of opening  48  slightly overlap opposite sides of inflation tube  36  to retain inflation tube  36  within channel  38 .  
         [0022]     A longitudinal movement of inflation tube  36  relative to handle body  16  is prevented by means of a lock assembly formed between a key  50  secured to inflation tube  36  and a corresponding key slot formed in handle body  16  transverse to channel  38 . The key slot in handle body  16  is positioned to align with the key  50  when temperature sensing array  18  is fully inserted into central channel  30 . The lock assembly further ensures that a precise location of the temperature sensor array  18  within channel  30  (shown in  FIG. 1 ) is maintained when probe  10  is in use.  
         [0023]      FIG. 3  is an exploded bottom view of probe  10  with the probe handle  12  separated from the balloon/sleeve assembly  14 . As shown in  FIG. 3 , probe handle  12  is removable and separable from the balloon/sleeve assembly  14  to permit probe handle  12 , i.e., and the temperature sensing array  18 , to be reused with a new sterile balloon/sleeve assembly. The balloon/sleeve assembly  14  includes the inflation tube  36 , which is connected between layers of the polymer material forming a balloon at the waist  34  of the balloon portion  26 , as will be described in greater detail. As shown in  FIG. 3A , the key  50  consists of a polymeric member having a flat edge portion  52 , a curved edge portion  54  and a hole  56  passing through the member to permit key  50  to be slid into a position on inflation tube  36  corresponding to key slot  58  in handle body  16 . Once key  50  is properly positioned, it is secured to inflation tube  36  by a suitable adhesive.  
         [0024]      FIG. 4  is an enlarged perspective view of the probe handle  12 , which shows that the handle body  16  is configured with a curved upper surface  60  and a flat lower surface  62 . This configuration of handle body  16  facilitates a proper orientation of the probe  10  relative to a patient and monitoring of the proper orientation during use. In a proper orientation, the flat lower surface  62  of handle body  16  contacts a treatment surface occupied by a patient in the supine position and is maintained in contact with the treatment surface by the weight of the patient on the handle body  16 . The configuration of handle body  16  thus inhibits any twisting of probe  10  by minor changes of position of the patient on the treatment surface.  
         [0025]     As shown in  FIG. 4 , temperature sensor array  18  extends from the proximal end  24  of handle body  16  at an upper extent of handle body  16 , and sensor cable  22  extends rearward of handle body  16  at a comparable upper extent. Temperature sensor array  18  is oriented in a plane that is generally parallel with the flat lower surface  62  of handle body  16 , with sensors  20  oriented on the upper surface of the flexible circuit.  
         [0026]     Channel  38  is generally centrally located relative to the flat lower surface  62 . Channel  38  is defined by a curved inner wall  64  which has an inner diameter that approximates the outer diameter of the inflation tube  36  for retaining the inflation tube  36  in channel  38 . The width of opening  48  of channel  38  is smaller than the inner diameter of inner wall  64 , which aids in the retention of inflation tube  36  within channel  38 . As shown in phantom, the key slot  54  is dimensioned and configured complimentary to key  50  to form a friction fit with key  50  when it is position within key slot  54 .  
         [0027]      FIG. 5  is an exploded view of the balloon/sleeve assembly  14 . As shown in  FIG. 5 , in one embodiment, the balloon/sleeve assembly  14  is comprised of a plurality of overlying and interconnected layers  70 ,  72 ,  74  and  76  which are connected together along a common peripheral edge such as by heat welding. Layers  70  and  76  are each a unitary layer of polymer that defines the top and bottom layers, respectively, of balloon portion  26  and the sleeve portion  28  of the balloon/sleeve assembly  14 . Edge portion  77  of layers  70  and  76  remain unconnected for inserting and removing probe handle  12  from the balloon/sleeve assembly  14 . Layers  72  and  74  are also each a unitary layer of polymer that is a postage stamp of balloon portion  26 , extending from a first end  42 A to an opposite end  78  corresponding to waist  34  of balloon/sleeve assembly  14 .  
         [0028]     Positioned between layers  70  and  72  adjacent to end  78  of layer  72  is a guide tube  80 , which facilitates insertion of the temperature sensor array  18  into the balloon portion  26 . Guide tube  80  is formed of a flexible polymer, such a Fluorinated Ethylene Plastic or Fluorinated Ethylene Propylene and is skived along a portion of the tube wall facing layer  70  to minimize the amount of material of balloon portion  26  that gets positioned within a patient, i.e., for patient comfort. Opposing edge portions  82  of guide tube  80  are secured to the peripheral edge regions of layers  70  and  72  to hold guide tube  80  in place. End  78  of layer  72  is left unconnected relative to layer  70 , such that guide tube  80  separates layers  70  and  72  slightly for easy insertion of the temperature sensor array  18 . Layers  70  and  72  are further interconnected by heat welding along seal lines  84  which define channel  30  for the temperature sensor array  18 .  
         [0029]     Positioned between layers  74  and  76  is the inflation tube  36 . Inflation tube  36  is oriented with the flat edge portion  52  of key  50  facing layer  76  and the axis of openings  46  perpendicular to the flat edge portion  52  of key  50 . Inflation tube  36  is sealingly connected between layers  74  and  76  at the waist  34  and along end  78 . Layers  74  and  76  thereby define an inflatable balloon, which when inflated results in layer  74  bearing directly against layer  72  and indirectly against layer  70  to urge the temperature sensor array  18  in close proximity to the wall of the rectum to be monitored. Layer  76  in turn bears against an opposite rectal wall portion to secure the balloon portion  26  in place in the rectum. In a preferred embodiment layers  70 ,  72 ,  74  and  76  have a wall thickness of about 0.2 mil (i.e., about 0.002 inches), which provides for good heat transfer across layer  70  to sensors  20  of the temperature sensor array  18 .  
         [0030]     In an alternate embodiment, balloon/sleeve assembly  14  may comprise only three layers consisting of layers  70 ,  72  and  76  that are connected in the manner described above. In such an embodiment, layers  70  and  72  are secured together about the perimeter and guide tube  80  is secured therebetween as previously described. Layers  70  and  72  are then heat sealed along seal lines  84  to form channel  30 . Thereafter, inflation tube is positioned between layers  76  and  72  and secured by sealing layer  76  to layer  72  about the perimeter and by sealing the side of layer  72  facing layer  76  to layer  76  along end  78 .  
         [0031]     In yet another alternate embodiment, layer  72  may be sized and shaped to define channel  30  and sealed about its perimeter to layer  70 , with guide tube  80  positioned as previously described between layers  70  and  72 . Inflation tube is positioned between layers  70  and  76  and secured by sealing layer  70  to layer  76  about the perimeter and by sealing the side of layer  70  facing layer  76  to layer  76  along end  78 .  
         [0032]      FIG. 6  is a cross-sectional view of the waist  34  of balloon portion  26 , which shows the peripheral heat welds  90  that interconnect peripheral edge portions of layers  70 ,  72 ,  74  and  76 .  FIG. 6  also shows adhesive layers  92 , which secure the opposing edge portions  82  of guide tube  80  to layers  70  and  72 . Finally, adhesive layer  94  is shown interconnecting end  78  of layer  74  to layer  76  and inflation tube  36  to create a fluid-tight seal at end  78  and thereby form a balloon between layers  74  and  76  that is inflatable and deflatable via the inflation tube  36 .  
         [0033]      FIG. 7  is a top view of probe handle  12  being introduced into balloon/sleeve assembly  14  for assembly of rectal temperature sensing probe  10 . As shown in  FIG. 7 , probe handle  12  is inserted through sleeve portion  28  and temperature sensor array  18  is positioned within guide tube  80 . Sleeve portion  28  maybe folded back over balloon portion  26  to facilitate locating guide tube  80 . In one embodiment, guide tube  80  is formed from a distinct color that is readily detectable through the transparent material forming balloon/sleeve assembly  14 , which makes the opening for temperature sensor array  18  into channel  30  easy to identify. Probe handle  12  is advanced until temperature sensor array  18  is completely within channel  30 , which occurs when key  50  on inflation tube  36  is aligned with the key slot  54  in the handle body  16 . Inflation tube  36  is then press fit through opening  48  and into channel  38  along the length of handle body  16  and key  50  is press fit into key slot  54 . With sleeve  28  covering handle body  16 , temperature sensing probe  10  is then ready for insertion and use in a patient.  
         [0034]     Inflation tube  36  is flexible but with sufficient longitudinal stiffness to enable advancement of tip  42  of balloon portion  26  into the desired position within the rectum of a patient. Balloon portion  26  is sized to engage the rectal wall when an inflation medium is introduced via the inflation tube  36  between layers  74  and  76  of the balloon portion  26 . With the inflation medium evacuated from the balloon formed by layers  74  and  76 , balloon portion  26  reduces to a more compact dimension for easy removal of the balloon portion  26  from the patient. To remove the balloon/sleeve assembly  14  from the probe handle  12 , the sleeve portion  28  is everted over balloon portion  26  to isolate the contaminated surface of balloon portion  26 . Inflation tube  36  and key  50  are then easily withdrawn from the channel  38  and key slot  58  in the handle body  16 . With the inflation tube  36  separated from the handle body  16 , probe handle  12  easily slides out of the balloon/sleeve assembly for subsequent re-use with a new balloon/sleeve assembly.  
         [0035]     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes maybe made in form and detail without departing from the spirit and scope of the invention.