Sphincterogram and Anal Exercising Device

This invention relates to sphincterograms, and more particularly to a hydraulic sphincterogram device and a sphincterography method which is especially adapted for use in diagnosis of anal dysfunction, such as anal incontinence and rectal prolapse, the sphincterogram device also being adapted for use as an anal sphincter exerciser.

Anal incontinence (the inadvertant release of rectal contents due to failure of the anorectal/pelvic musculature) and rectal prolapse (the protrusion of the rectum through the anus) are common, embarrassing and, not surprisingly, under-diagnosed problems. It has been suggested that two distinct muscular mechanisms maintain fecal continence: (1) squeeze of the muscle fibers of the anal sphincter closes the anal canal lumen, and (2) contraction of the puborectalis--levator ani muscles flattens the distal rectum horizontally and kinks it at the anorectal angle thereby preventing transmission of intra-abdominal pressure into the anal canal. Anal incontinence may be associated with short anal canal length, low anal squeeze pressures and a wide (flat) anorectal angle. Rectal prolapse may be associated with a flat anorectal angle with or without low squeeze pressures.

Radiographic studies have been developed which allow actual visualization of the anal canal and measurement of the anorectal angle. These studies have heretofore been tedious, time consuming, unpleasant and messy. For example, S. Phillips and D. Edwards, Some Aspects of Anal Continence and Defaecation, 6 Gut 396-406 (1965), disclosed a method for determining the shape and position of the anal canal during defecation with cineradiography after coating the mucosa of the anal canal with barium sulfate powder. Barium soaked swabs, metal beaded chains, and various consistancies of barium have also been used to determine the anorectal angle.

The use of a balloon proctogram has been suggested as a tool for diagnosis of anal function. For example, Preston, Lennard-Jones and Thomas, The Balloon Proctogram, 71 Br. J. Surg 29 (1984), discloses a barium filled balloon used to simulate a soft stool After insertion and inflation of the balloon, a patient sits on a radiolucent lavatory seat. While the patient is sitting, the level of the pelvic floor, change of the anorectal angle and behavior of the anal sphincters during straining and defecation are visually demonstrated with lateral radiographs.

While the simplicity and cleanliness of this barium filled balloon is desirable, the particular design described above is disadvatageous in that it does not provide for measurement of anal canal (sphincter) pressure and fatigability of the anal musculature. The other methods outlined above, in addition to being unpleasant and messy, share this disadvantage. Therefore, one distinct muscular mechanism for maintaining anal continence has been ignored by these approaches to diagnosis of anal incontinence.

Also, these techniques do not provide for exercise of the anal sphincter, which may be a promising treatment for some forms of anal dysfunction, such as anal incontinence. "Anal aerobics", however, is not part of the traditional treatment of anal incontinence. An exercise for strengthening the anal musculature should include repeated relaxation and contraction of the anal sphincter. By definition, contraction must be against pressure that is below the maximum anal canal squeeze pressure and above the opening pressure of the resting anal sphincter. Any apparatus and method for exercising the anal musculature should be easy to use and designed to prevent excessive strain and internal injuries. Ideally, an apparatus and method for anal exercises should be capable of determining anal function, and an apparatus and method for determining anal function should be capable of exercising the anal musculature.

Among the several objects of this invention may be noted the provision of a sphincterogram device and sphincterography method which are safe, reliable, easy and not unpleasant to use, and which measures a patient's anal canal length, anal canal pressure, anorectal angle, fatigability of the anal musculature and the like. Also, some other objects of this invention are the provision of a sphincter exercising apparatus and method that is safe, reliable and easy to use. Another object of this invention is the provision of a sphincterogram that is capable of use for sphincter exercising.

Generally, a sphincterogram device of the present invention is used with radiographic equipment for measuring a patient's anal canal length, anal canal pressure, anorectal angle, and fatigability of the anal musculature. It comprises an elongated expandable balloon having a flexible tubular catheter disposed substantially therein and secured to the distal end thereof. The catheter has a free open end terminating within the balloon in communication with the interior of the balloon. The balloon is adapted for insertion into the patient's anal canal. The catheter has multiple openings spaced along a substantial portion of its length for communicating between the interior of the balloon and the interior of the catheter. The catheter is sufficiently flexible to bend when inserted in the anal canal, and has its free open end unimpeded by any external connection, such as a connection to a fluid conduit or flow line, for freedom of movement to conform substantially to the anal canal so that the anorectal angle may be measured. The sphincterogram device also includes at least one fluid supply reservoir and at least one fluid flow line interconnecting the reservoir and the balloon for flow of fluid between them. Pressurizing means is operable on the fluid supply reservoir for adjusting fluid pressure therein and for adjusting fluid pressure and volume in the catheter and balloon, and calibration means is associated with the pressurizing means for determining fluid pressure within the balloon. In other words, raising the fluid reservoir increases the pressure inside the sphincterogram balloon and measuring the elevation of the reservoir above the balloon allows the user to calculate pressure within the balloon.

In a second aspect of this invention, the apparatus, which also constitutes an anal spincter exerciser, comprises an elongated expandable balloon having a flexible tubular catheter disposed substantially therein. The balloon is adapted for insertion into the patient's anal canal. The catheter has a plurality of openings spaced along a substantial portion of its length for communicating between the interior of the balloon and the interior of the catheter. The exerciser also includes a fluid supply reservoir and a fluid retention reservoir. The fluid supply reservoir communicates with the catheter and balloon through a first fluid flow line, one end of which is connected to the balloon and the other end of which is connected to the fluid supply reservoir. The fluid retention reservoir communicates with the catheter and balloon through a second fluid flow line, one end of which is connected to the balloon and the other end of which is connected to the fluid retention reservoir. Fluid is contained within the balloon, catheter, first fluid flow line, fluid supply reservoir, second fluid flow line and fluid retention reservoir. The first fluid flow line has a first one way valve therein, which allows fluid flow toward the balloon and prevents fluid flow toward the fluid supply reservoir, and the second fluid flow line has a second one way valve therein, which allows fluid flow away from the balloon and prevents fluid flow away from the fluid retention reservoir. This arrangement causes minimum fluid pressure within the balloon to be dependent on the pressure at the fluid supply reservoir side of the first one way valve and maximum fluid pressure within the balloon to be dependent on the fluid pressure required for fluid flow into the fluid retention reservoir. First means is operable on the fluid supply reservoir for varying the elevation of the fluid supply reservoir, which varies the fluid pressure at the reservoir side of the first one way valve, thereby adjusting the minimum fluid pressure within the balloon. Second means is operable on the fluid retention reservoir for varying the elevation of the fluid retention reservoir, which varies the fluid pressure required for fluid flow into the fluid retention reservoir, thereby adjusting the maximum fluid pressure within the balloon.

Also disclosed are methods for exercising the anal sphincter and measuring various aspects of anal function, such as anal canal length, anal canal pressure, anorectal angle, and fatigability of the anal musculature.

Other objects and features will be in part apparent and in part pointed out hereinafter.

FIG. 1 is a side elevation of a sphincterogram device of the present invention illustrating a patient receiving a sphincterogram;

FIG. 2 is a side view, partly in cross section, of a balloon catheter for the sphincterogram device of FIG. 1;

FIG. 3 is a side elevation similar to FIG. 1 showing use of the sphincterogram device as a sphincter exerciser;

FIG. 4 is a side view of a normal subject's rectal region, showing an anorectal angle and anal canal length;

FIG. 5 is a side view, similar to FIG. 4, of the rectal region of a patient suffering from rectal prolapse; and

FIG. 6 is a side view, similar to FIG. 4, of the rectal region of a patient suffering from chronic constipation.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to the drawings, a sphincterogram device of the present invention is designated in its entirety by the reference numeral 1. As shown in FIG. 1, the sphincterogram device comprises a balloon catheter 3, at least one fluid flow line 5 (or first fluid flow line), and fluid supply reservoir 7. The fluid supply reservoir may be suspended by a first stand 9. Preferably, radiopaque fluid 11 is contained within the balloon catheter 3, first flow line 5, and fluid supply reservoir 7. For example, low viscosity radiographic contrast, sold under the trade designation "Cystograffin", may be used.

As shown in FIG. 2, the balloon catheter 3 comprises an elongate catheter 13 and an elongated expandable balloon 15. The catheter 13 may be relatively flexible (e.g., of rubber) so as to bend with the contour of an anal canal and rectum, but firm enough to be inserted in the anal canal. It may be tubular (hollow) and have a plurality of openings or perforations 17 spaced along a substantial portion of its length. These perforations facilitate fluid movement within the balloon catheter 3 even when a section or sections of the balloon are collapsed. This maintains an even fluid pressure throughout the balloon during use. Preferably, the catheter is a 16 French catheter having a 20 cm length, and the perforations have a 5 mm diameter.

The balloon 15 may be constructed of a one inch (25 mm) Penrose drain, having an unstretched circumference of 3.14 inches (80 mm). It may be attached to the catheter at 19 by any suitable method of attachment and sealing. The balloon preferably has a length of 30 cm from the attachment area 19 to one end 21 of the first fluid flow line 5, which is where the balloon catheter is connected to the first fluid line. Any suitable method of attachment to the first line 5 that is strong and prevents leaking should be acceptable. The first line may be a large diameter flexible tube (having e.g., a 5/8 inch (16 mm) lumenal diameter).

As shown in FIG. 1, the other end 23 of the first fluid line is connected to the fluid supply reservoir 7, so that the fluid supply reservoir 7 may communicate with the balloon catheter 3 through the first fluid flow line 5. Thus, the radiopaque fluid may move or flow through the first line between the fluid supply reservoir and the balloon catheter. The elevation of the fluid supply reservoir 7 may be varied by moving it along an upright member 25 of first stand 9. An increasing elevation of the fluid supply reservoir 7 relative to the balloon catheter 3 causes increasing fluid pressure and possibly increasing fluid volume within the balloon catheter. Also, any relative elevation of the fluid supply reservoir corresponds to a specific fluid pressure within the balloon catheter. The stand 9 constitutes pressurizing means operable on the fluid supply reservoir 7 and first means operable on the fluid supply reservoir for adjusting fluid pressure within the balloon catheter 3 whereby fluid pressure within the balloon catheter are varied.

The upright member 25 of the first stand may be marked at constant intervals so as to calibrate the stand for easier determination of the first reservoir's elevation relative to the balloon catheter. Alternatively, hooks 27 may be at constant intervals along the upright member 25 for the same purpose. Therefore, marks, hooks 27 or the like constitute first calibration means for determining fluid pressure within the balloon catheter.

The fluid supply reservoir 7 may be, for example, an ordinary enema bag. Preferably, it has a large volume relative to the balloon catheter 3. Because of this large relative volume, any change of the volume of the balloon catheter causes only a small change in the elevation of the fluid within the fluid reservoir. Since the elevation of the fluid is only minimally affected by the balloon catheter's shape and size, the fluid pressure within the balloon catheter is only minimally affected by such changes in shape and size. This feature of stable pressure permits accurate measurement of sphincter pressure.

Referring to FIG. 3, a second embodiment of the present invention can be utilized as an anal sphincter exerciser, which is generally designated in its entirety by the reference numeral 29. The exerciser comprises a fluid retention reservoir 29, an additional (or second) fluid flow line 31, and a second stand 33 in addition to the features of the sphincterogram device. The fluid retention reservoir 29 may be of identical construction as the fluid supply reservoir 7. However, the exerciser does not require radiopaque fluid unless it is also being used to obtain a sphincterogram. If the exerciser is being used solely for exercise of the anal sphincter, it only requires a suitable fluid for that use.

Instead of directly connecting the first and second fluid flow lines to the balloon catheter 3, a Y-connector 34 may be used. The first fluid flow line 5 may have a first one way valve 35 therein, and the second fluid flow line 31 may have a second one way valve 37 therein. The first valve 35 allows fluid flow toward the balloon catheter 3 and prevents fluid flow toward the fluid supply reservoir 7, while the second valve 37 allows fluid flow away from the balloon catheter 3 and prevents fluid flow away from the fluid retention reservoir 29. This arrangement causes (1) the minimum possible fluid pressure within the balloon catheter 3 to be dependent on the pressure at the fluid supply reservoir side of the first one way valve 35, and (2) the maximum possible fluid pressure within the balloon catheter 3 to be dependent on the fluid pressure required for fluid flow into the fluid retention reservoir 29. It is understood that the first fluid flow line 5 may only have a one way valve when more than one fluid reservoir is attached (e.g., fluid supply reservoir 7 and fluid retention reservoir 29). Otherwise, fluid may not be able to escape from the balloon.

Therefore, the first stand 9 constitutes first means operating on the fluid supply reservoir 7 for varying the elevation of the fluid supply reservoir whereby the minimum fluid pressure within the balloon catheter 3 is controlled by varying the fluid pressure at the fluid supply reservoir side of the first one way valve 35. The second stand 33 constitutes second means operable on the fluid retention reservoir 29 for varying the elevation of the fluid retention reservoir whereby the maximum fluid pressure within the balloon catheter 3 is controlled by varying the fluid pressure required for fluid flow into the fluid retention reservoir.

It is not necessary to use the two reservoir embodiment to perform diagnostic radiographic studies. To perform sphincterography, a patient may be placed, left side down, on a fluoroscopy table 39. Then approximately six inches (150 mm) of the deflated (and lubricated) balloon catheter 3 may be placed in the anal canal and distal rectum. Fluoroscopy may be utilized to visually demonstrate the patient's anal function. (Fluoroscopy is used herein as any method to produce a continuous X-ray picture or the like; radiography means any method to produce an X-ray picture and the like, including fluoroscopy.) Various measurements relevant to anal function may then be made.

First, the fluid supply reservoir 7 may be raised in increments, so that the fluid pressure within the balloon 15 is raised in increments until it is seen to open the resting anal canal. The pressure may be calculated by multiplying the fluid supply reservoir's height relative to the balloon by the density of the radiopaque fluid relative to water. In this case, the result is the opening pressure of the anal sphincter in centimeters of water.

Second, to determine the patient's maximum anal canal squeeze, the patient may voluntarily squeeze his anal sphincter against low balloon pressure, so that the balloon collapses. Then the pressure within the balloon may be raised in increments until the patient is unable to collapse it with his squeeze. The maximum anal canal squeeze pressure is the highest pressure at which the patient is able to collapse the balloon within the anal canal. Permanent single full-size radiographs may be taken during initial maximum squeeze at balloon pressures of 20 cm H.sub.2 O, 40 cm H.sub.2 O, 60 cm H.sub.2 O, and 80 cm H.sub.2 O for easy measurement and documentation.

As shown in FIGS. 4-6, the anorectal angle A is the angle between the axis of the anal canal X and the rectal ledge L. It may be measured at any time during sphincterography, but a preferred standard procedure for accurate comparisons between patients is to measure the angle during initial voluntary anal squeeze with a balloon pressure of 40 cm water. Also, the length of the anal canal (the distance D between the rectal ledge L and the anal verge V) may be measured at this time.

The anorectal angle A is normally approximately 100-110 degrees, as shown in FIG. 4. If the patient has prolapse or anal incontinence the angle A may be relatively flat (e.g., approximately 130 degrees), as shown in FIG. 5. A patient suffering from chronic constipation may have a relatively small anorectal angle A (e.g., approximately 90 degrees), as shown in FIG. 6.

The sphincterogram device may also be used to exercise a patient's anal sphincter when both fluid reservoirs are connected. Preferably, the fluid supply reservoir 7 is filled with fluid and the fluid retention reservoir 29 is empty. The balloon catheter 3 is placed inside the anal canal. Then the fluid retention reservoir 29 may be raised to an elevation below that which obtains the maximum squeeze pressure within the balloon. Next, the fluid supply reservoir 7 may be raised until the opening pressure of the anal canal is obtained within the balloon 15. This is the precise pressure sufficient to inflate the balloon while the sphincter is relaxed. It is also the minimum possible fluid pressure within the balloon catheter 3 during the exercises. The sphincterogram device is now ready for the patient to begin the exercises.

The patient may exercise the anal sphincter by voluntarily contracting his or her anal sphincter, thereby forcing fluid out of the balloon 15 into the fluid retention reservoir 29. The higher the elevation of the fluid retention reservoir 29, the greater the pressure the sphincter must generate to compress the balloon and, thereby, force fluid into the fluid retention reservoir 29. After the patient has compressed the balloon, he or she may relax his or her sphincter, allowing the balloon to fill up again with fluid from the fluid supply reservoir 7. The balloon is now ready for another compression. This process may be repeated until the fluid supply reservoir is empty.

It will be observed from the foregoing that the spincterogram and sphincterography method of the present invention provides an apparatus and method for diagnosis of anal dysfunction and exercise of the anal sphincter, which is easy and not unduly unpleasant to use, and which allows low exposure to radiation.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.