Abstract:
An apparatus and method for measuring the size of a body passage is provided. The apparatus comprises a flexible strip having first and second ends. At least one aperture is disposed on the strip between the first and second ends. An indicia of body passage circumference is disposed on the strip in association with the at least one aperture. The body passage may be measured by inserting the strip into a dissected tunnel around the body passage, manipulating the strip such that the strip substantially surrounds the body passage, and observing the indicia on the strip to generally determine the circumference of the body passage.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to cuff sizers for estimating the girth of a body passage and particularly to cuff sizers used in procedures for the implantation of artificial sphincters. 
     BACKGROUND OF THE INVENTION 
     Incontinence is the inability to voluntarily control the discharge of excretory materials and is typically caused by physical, neurological or psychological traumas. Incontinence is a major medical problem that affects millions of people and extends across all age groups. Moreover, this condition often results in serious discomfort and embarrassment of the patient, often forcing those affected to withdraw from regular social activities. 
     To address and treat incontinence and to assist affected patients in returning to a degree of normalcy in this area, surgical processes and devices have been developed which are intended to restore the lost anatomical functions. Many of these surgical processes employ devices whose function it is to selectively occlude the affected body passage upon the desire of the patient. Inflatable fluid actuated artificial urinary sphincters (AUS) are one type of such known devices and their function is to selectively occlude the urethra. Fluid actuated artificial bowel sphincters (ABS) are another type of device and their function is to selectively occlude the anus. 
     Referring to FIG. 1, an example of a fluid actuated ABS  10  is illustrated. However, it should be noted that an AUS has a similar configuration. The ABS  10  includes an inflatable cuff  12  configured to surround and occlude the anus  14 , a pressure regulating balloon  16  to store actuating fluid, and a control pump  18  to transfer the actuating fluid from the balloon  16  to the cuff  12  and from the cuff  12  to the balloon  16 . 
     For a female patient, the pump  18  is implanted in the labia  20 , and the balloon  16  is implanted in the abdomen such as the space of retzius. For a male patient, the pump may be implanted in the scrotum, and the balloon may be implanted in the abdomen such as the space of retzius. 
     The basic components of these devices are connected by fluid transmission lines  24 ,  26 . One fluid transmission line  24  or conduit connects the cuff  12  with the pump  18 , and the second fluid transmission line  26  or conduit connects the pump  18  with the balloon  16 . The cuff  12  is inflated to occlude the anus  14  and deflated to allow the discharge of feces through the anus  14 . Normally, the cuff  12  is maintained in an inflated (closed) position. 
     One of the difficulties associated with an inflatable fluid actuated sphincter is that the implanted cuff may be improperly sized for the particular anus or urethra due to the difficultiness of determining the anal or urethral girth during surgery. A cuff which is over-sized may lead to unreliable coaptation or closure of the anal or urethral tissue, thus defeating the purpose of implanting the cuff, while a cuff which under-sized may cause damage to the circumscribed tissue or unduly restrict the size of the cuffed passage. Thus, there exists a need for a device and method to assist the surgeons in a more accurate determination of the anal or urethral girth of a patient for selecting an appropriately sized cuff during the surgical procedure. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with the present invention, a locking cuff sizer for determing the size of a body passage is provided. The cuff sizer is particularly suited for properly sizing the anal or urethral girth during surgical implantation of an ABS or AUS device. In accordance with an illustrative embodiment of the present invention, the cuff sizer includes a flexible strip having first and second ends. A plurality of apertures are disposed between the first and second ends of the strip, and the plurality of apertures are aligned along a longitudinal axis of the strip. Indices of body passage circumference are disposed on the strip in association with each of the plurality of apertures. An adapter is disposed near the first end of the strip, and the adapter engages with one of the plurality of holes to lock the cuff sizer around the body passage. 
     The strip is inserted into a dissected tunnel around the body passage and manipulated such that the strip substantially surrounds the body passage. By securing the adapter onto one of the plurality of apertures, the cuff sizer is locked around the circumference of the body passage. Once “locked”, the surgeon may evaluate the tightness of the “locked” position by sliding the cuff sizer along the body passage. If the cuff sizer is overly tight or loose, it may be “unlocked” and another aperture may be selected. When the appropriate aperture is selected, measurement of the body passage may be observed by viewing the indicia in association with the appropriate aperture. After determining the correct cuff size, the cuff sizer is removed, and a correctly sized cuff is implanted into the patient. 
     To aid in the insertion, manipulation, and securement of the cuff sizer around the circumference of the body passage, the cuff sizer may include an introducer such as a flexible tubing having first and second ends, wherein the first end is connected to the adapter. The cuff sizer may be introduced into the dissected tunnel by first inserting the introducer through the dissected tunnel. The strip may then be drawn through the dissected tunnel by pulling the introducer. The cuff sizer may then be secured into its “locked” position by passing the second end of the introducer through the desired aperture and securing the adapter onto the appropriate aperture. 
     Other objects, features, and advantages of the present invention will become apparent from a consideration of the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is an artifical bowel sphincter as placed in a patient 
     FIG. 2 is a perspective view of a locking cuff sizer in accordance with the present invention; 
     FIG. 3 is a plan top view of the locking cuff sizer shown in FIG. 2; 
     FIG. 4 is a plan side view of the locking cuff sizer shown in FIG. 2; 
     FIG. 5 is a perspective view of the locking cuff sizer of FIG. 2 shown in a “locked” configuration; 
     FIG. 6 illustrates a cross-sectional view of the locking cuff sizer along line  5 — 5  of FIG. 5; and 
     FIG. 7 schematically illustrates the locking cuff sizer shown in FIG. 2 secured to a body passage. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 2-4, an exemplary embodiment of a locking cuff sizer  50  of the present invention is illustrated for determining anal girth and includes a tape element  52 , a plurality of holes  54 , an adapter  56 , and an introducer  58 . A similarly constructed device is usable for determining urethral girth. 
     The tape element  52  is approximately 23 cm in length, 2 cm in width, and 0.1 cm in thickness, however, depending on the size of the anus, smaller or larger dimensioned tape elements may be used. Both distal  60  and proximal ends  62  of the tape element  52  are tapered to facilitate the cuff sizer  50  being inserted and/or passed through tunnels formed in the anal tissues during surgery, and the tape element  52  has a front  64  and back surface  66 . 
     The plurality of holes  54  are aligned in a single row fashion substantially along the longitudinal axis of the tape element  52  and in the embodiment illustrated in FIGS. 2-4, the cuff sizer  50  has eight such holes  54 . Corresponding to each hole  54  is an identification mark indicating the circumferences of a body passage such as an anus. For example, the hole  54  marked as “10” refers to a measured circumference of 10 cm. Each of the holes  54  has a diameter of approximately 0.8 cm, and the center to center distance between adjacent holes  54  is 1 cm. 
     The tape element  52  is flexible such that it can be readily wrapped around a body passage during surgery. In addition, the tape element  52  is compliant to reduce injury to tissue during the surgical procedure. For example, in one embodiment the tape element  52  is formed from a sheet of solid silicone elastomer wherein the sheet is cut into the desired shape, and the plurality of holes are formed during the die cutting process. Other types of flexible polymers such as urethane or other suitable materials known in the art may also be used. Furthermore, the tape element may be formed into the desired shape by other fabrication processes such as machining, injection molding, or other processes known in the art. 
     Referring to FIGS. 2-4, the adapter  56  is cylindrically shaped and has a distal end  68  and a proximal end  70 . The adapter  56  has a length of about 1.5 cm and a diameter of about 0.7 cm, and a flat base portion  72  of the adapter  56  faces the front surface  64  of the tape element  52 . The base portion  72  is connected to the top surface  64  of the tape element  52  by a post  74 , wherein a receiving slot  76  is formed between the surface of the base portion  72  and the front surface  64  of the tape element  52 . The receiving slot  76  is sized such that it is slightly less than the thickness of the tape element  52 . 
     The introducer  58  has a proximal end  78  and a distal end  80  wherein the proximal end  78  is coupled to the distal end  68  of the adapter  56 . The introducer  58  may be a flexible tubing with a length of about 32 cm, an outer wall diameter of about 0.3 cm, and an inner wall diameter of about 0.1 cm. A spiral-shaped groove  82  is formed on the surface of the introducer  58  to provide a gripping surface for the surgeon and to enhance longitudinal stretchability. In one preferred embodiment, the adapter  56  and introducer  58  are made of a solid silicone elastomer. However, the adapter and introducer may be formed from various other polymers or suitable materials. 
     Referring to FIGS. 5 and 6, the cuff sizer  50  is shown in its locked position wherein the adapter  56  is lockingly engaged with hole  54  identified by the mark “11”. The cuff sizer  50  is manipulated into its “locked” position by passing the introducer  58  from the back surface  66  of the tape element  52  and through the desired hole  54 . With the introducer  58  completely drawn through the desired hole  54 , the desired hole  54  is stretched as the adapter  56  is passed through the desired hole  54 . Thus, the tape element  52  should be adequately resilient to allow the hole  54  to stretch and yet capable of returning to its original, unstressed dimension in order to obtain accurate girth measurements. The cuff sizer  50  is in its “locked” position when a side wall  84  of the desired hole  54  is engaged with the receiving slot  76  of the adapter  56 . Referring to FIG. 7, the locking cuff sizer  50  is secured around a body passage  86 , such as an anus, in order to perform a measurement. 
     It is noted that the present invention is not limited to the circular hole and adapter configuration described above. Openings such as slits may be used instead of the circular holes, and the adapter may be configured in any form as long as it is able to pass through an opening and “lock” the tape element. In addition, smaller or larger dimensioned cuff sizers may be used. For example, a smaller dimensioned cuff sizer is preferable for determining urethral girth, while larger cuff sizers are preferable for measuring the anus of a large patient. It is contemplated that cuff sizers should be capable of making girth measurements ranging from about 3 cm to about 20 cm, wherein the tape element may have a length of about 10 cm to 35 cm and a width of about 1 cm to 5 cm. Furthermore, the introducer may comprise a wire having non-elastic characteristics or another elongated member such as a cord. 
     The anal girth of a female patient may be determined according to the following surgical procedure. The patient is placed in a modified lithotomy position on the operating table with legs in Allen stirrups. Two lateral perianal incisions staying extrasphincterically are formed. The incisions are deepened into the ischiorectal fossa. Using blunt finger dissection, a posterior tunnel is formed distal to the coccyx and behind the distal rectum or upper anal canal. Electrocautery may be used to divide tougher tissue. A penrose drain is placed in the posterior tunnel. An anterior tunnel is created extrasphincterically by using blunt finger dissection and using electrocautery to divide tougher tissue. It is noted that other surgical procedures such as a single, anterior-transverse incision may be performed to determine the anal girth. 
     Once the anterior tunnel is completed, the ideal length of a cuff to be implanted is determined by utilizing the locking cuff sizer. The penrose drain is removed, and the introducer is inserted into a first end of the anterior tunnel. A Statinsky clamp is inserted into a second end of the anterior tunnel and clamped onto the introducer, and the introducer and tape element are drawn through the anterior tunnel. After unclamping the introducer, the introducer is inserted into a first end of the posterior tunnel (the first end of the posterior tunnel is adjacent the second end of the anterior tunnel). The Statinksy clamp is inserted into a second end of the posterior tunnel (the second end of the posterior tunnel is adjacent the first end of the anterior tunnel) and clamped onto the introducer. The introducer and tape element are drawn through the posterior tunnel. At this stage of the surgical procedure, the proximal end of the tape element is extending outside the first end of the anterior tunnel, and the distal end of the tape element is extending outside the second end of the posterior tunnel. As described above, the cuff sizer is manipulated into its “locked” position by passing the distal end of the introducer through the desired hole, and the side wall of the desired hole is engaged with the receiving slot. 
     Once “locked”, the surgeon may evaluate the tightness of the “locked” position by sliding the cuff sizer along the anus. If the cuff sizer is overly tight or loose, it may be “unlocked” and another hole may be selected. When the appropriate hole is selected, measurement of the anus may be noted by viewing the mark which corresponds to the appropriate hole. After determing the correct cuff size, the cuff sizer is removed, and a correctly sized cuff is implanted into the patient. To aid in the implantation of the cuff, the cuff may be attached to the cuff sizer and drawn through the anterior and posterior tunnels as the cuff sizer is removed. 
     As known to one skilled in the art, a similar surgical procedure may be performed to measure the anal girth of a male patient. Obviously, certain steps may differ due to the anatomical differences between a male and female patient. 
     Although the present invention has been described in detail with regarding the exemplary embodiment and drawings thereof, it should be apparent to those skilled in the art that various adaptations may be accomplished without departing from the spirit and scope of the invention. Accordingly, the invention is not limited to the precise embodiment shown in the drawings and described in detail hereinabove. For example, the cuff sizer may be “locked” by other means such as snap fasteners comprising a plurality of male sections disposed on a front surface of the tape element and a plurality of female section disposed on the back surface of the tape element, wherein the cuff sizer is “locked” by fastening the male section onto the female section.