Gastrostomy tube

A gastrostomy tube has a retaining element which has a generally triangular shape with rounded vertices. The retaining element is made up of three resilient petaloid flanges which extend radially from the tubular portion of the gastrostomy tube. The petaloid flanges and the tubular portion are made of different materials. Substantially triangular connecting portions are interposed between and interconnect each pair of next adjacent petaloid flanges. The petaloid flanges are rendered less flexible than the connecting portions by either variations in thickness or materials between the petaloid flanges and connecting portions. The assembly of a gastrostomy tube and a tapered dilator is also disclosed.

The present invention relates to a gastrostomy tube, and more particularly 
to a gastrostomy tube which can accommodate internal passage therethrough 
of a feeding tube. 
A surgical procedure wherein an opening is formed in the skin, fascia and 
stomach wall and a tube is installed in the opening to allow nutrition to 
be provided directly into the stomach or intestines is known as a 
gastrostomy. A tube which is inserted through the opening made during the 
surgical procedure to maintain the opening is known as a gastrostomy tube. 
Examples of individuals who would require such a procedure include burn 
patients, whose daily caloric needs are very high; critically ill, weak or 
comatose patients who may be unable to chew their food; and patients 
suffering from a diseased or traumatized esophagus, who may be unable to 
swallow food. 
The gastrostomy tube of the present invention is adapted for placement in a 
patient using the Sacks-Vine procedure, sometimes referred to as a "push" 
procedure. Briefly, this procedure entails the following steps: (a) 
passing an endoscope through the esophagus into the stomach; (b) locating 
a suitable site for the gastrostomy; (c) passing a Seldinger needle 
through the abdominal wall into the stomach, removing the inner stylet and 
leaving the outer cannula in place, then inserting a snare via the 
endoscope and looping the snare over the end of the cannula; (d) inserting 
a guidewire through the Seldinger Needle into the stomach, grasping the 
guidewire via the snare, and withdrawing the endoscope to deliver the 
guidewire through the mouth; (e) advancing the gastrostomy tube over the 
guidewire until the gastrostomy tube reaches the cannula and pushes the 
cannula through the abdominal wall; (f) gently pulling the gastrostomy 
tube through the abdominal wall until the retaining element of the tube 
engages the gastric mucosa; and (g) securing the gastrostomy tube in place 
by sliding a retention disc over the portion of the gastrostomy tube which 
now protrudes through the patient's abdomen, and then cutting off the 
excess length of the gastrostomy tube. The Sacks-Vine procedure is well 
known, and has been described for example in THE AMERICAN JOURNAL OF 
GASTROENTEROLOGY ("A CRITICAL ANALYSIS OF THE SACKS-VINE GASTROSTOMY TUBE 
A REVIEW OF 120 CONSECUTIVE PROCEDURES", P. G. Foutch, et. al., THE 
AMERICAN JOURNAL OF GASTROENTEROLOGY, August 1988, Pages 812-815) and 
books such as ATLAS OF NUTRITIONAL SUPPORT TECHNIQUES, John L. Rombeau, 
et. al, Little, Brown and Company, 1989, Pages 132-136. 
U.S Pat. No. 4,758,219 teaches a gastrostomy tube and an assembly of a 
dilator and a gastrostomy tube. The actual retaining element is a separate 
piece of tubing which is affixed such that it extends perpendicular to the 
axis of the gastrostomy tube. The retaining element of the gastrostomy 
tube is secured in place by a multi-wing releasable lock formed from the 
wall of the gastrotomy tube by slitting the tube longitudinally over a 
predetermined length at a selected number of points about the 
circumference of the tube. A special instrument must be inserted into the 
gastrostomy tube to unlock the locking mechanism when the gastrostomy tube 
is removed from a patient, and the short piece of tubing that serves as 
the retaining element is separated from the gastrostomy tube at that time. 
This prior art device has only the tubular retaining element to seal the 
stoma against leakage, and will necessarily have a higher contact pressure 
against the stomach mucosa than the retaining element of the gastrostomy 
tube disclosed herein. 
There are, of course, other accepted procedures for performing a 
gastrostomy, and inserting a gastrostomy tube. For example, U.S. Pat. No. 
4,668,225 teaches a gastrostomy tube which is adapted for insertion into 
the stomach through an incision in a patient's abdomen. The retaining 
element of the gastrostomy tube taught in this document comprises a 
plurality of resilient flanges which are interconnected by hub portions 
which extend outwardly from the tube a lesser distance than the flanges, 
however; this gastrostomy tube leaves unsolved the problems of premature 
tube removal and migration of the retaining element and tube out of the 
stomach into the fasciae, thus allowing the stomach to no longer be in 
opposition to the abdominal wall. This can result in leakage of gastric 
contents, or direct feeding of a nutritional product into the peritoneum 
with the possible onset of peritonitis. This problem is overcome by a 
gastrostomy tube according to the present invention by providing a 
retaining element with significantly more surface area than the prior art 
retaining element, thereby decreasing pressure on the stomach wall while 
maintaining the gastrostomy tube in the desired position thus decreasing 
the probability of gastric exchange through the stoma site.

DETAILED DESCRIPTION OF THE INVENTION 
Referring first to FIGS. 1-5 there is shown a gastrostomy tube according to 
a first embodiment of the invention. FIG. 1 is a perspective view; FIG. 2 
is a front elevation view looking in the direction indicated by arrow 2 in 
FIG. 1; FIG. 3 is a side elevation view, partially broken away; FIG. 4 is 
a rear elevation view; and FIG. 5 is a partial side elevation view with 
the retaining element partially folded over onto itself. 
A gastrostomy tube 20 according to the invention comprises a tubular 
portion 21 having first and second ends 22, 23 and a retaining element 24 
disposed near the first end 22 of the tubular portion. A lumen 25 extends 
from the first end to the second end of the tubular portion. The section 
35 of the tubular portion which is disposed between the first end 22 of 
the tubular portion 21 and the retaining element 24 has a larger outside 
diameter and wall thickness than the remainder of the length of the 
tubular portion. In a working example the outside diameter of a first 
section 35 of the tubular portion 21 which is disposed between the first 
end 22 and the retaining element 24 has an outside diameter of about 8.8 
mm (0.345 inch), and a second section 36 of the tubular portion disposed 
between the second end 23 and the retaining element 24 has an outside 
diameter of about 6.2 mm (0.246 inch), which diameter is commonly referred 
to as size eighteen French. The lumen 25 has a diameter which is constant 
along the entire length of the tube, and in the working example that 
diameter is about 4.5 mm (0.176 inch). As a result, the thickness of the 
wall of the tubular portion is about 141% greater in the first section 35 
of the tubular portion than in the second section 36. A circular collar 26 
is located at or near the first end 22 of the tubular portion 21 and 
functions in cooperation with the thick section 35 of the tubular portion 
as a site which an endoscopist may snare when the gastrostomy tube is 
removed, and extracted through the patients' esophagus. 
In each embodiment of the invention the retaining element 24 comprises 
three resilient petaloid flanges 27, 28, 29 which extend radially from the 
tubular portion 21. As used herein and in the claims "petaloid" is 
understood to mean a shape resembling a flower petal, being narrowest at 
its junction with the tubular portion then becoming wider and then 
narrower at the portion of the flange which is distal from the tubular 
portion. Substantially triangular connecting portions 30, 31, 32 are 
interposed between each pair of next adjacent petaloid flanges, and 
function in part to connect the petaloid flanges to one another. It is to 
be noted that in the specific embodiment illustrated in FIGS. 1-5 the 
petaloid flanges 27, 28, 29 comprise an opaque material while the 
connecting portions 30, 31, 32 comprise a transparent material which also 
encases the petaloid flanges. It is understood however that any 
combination of two transparent, two opaque, or one of each type of 
material may be employed in this embodiment subject only to other 
properties of the materials which will be described later. The ends of the 
petaloid flanges which are distal from the tubular portion are rounded, 
and the petaloid flanges and connecting flanges are shaped such that the 
retaining element 24 in front or rear elevation (as shown in FIGS. 2, 4, 7 
and 9) has a triangular shape with rounded vertices. 
It is an important feature of a gastrostomy tube according to the invention 
that in the retaining element 24 the petaloid flanges 27, 28, 29 are less 
flexible than the connecting portions 30, 31, 32. This feature allows the 
retaining element to collapse towards the tubular portion as illustrated 
in FIG. 5 such that the retaining element 24 may pass through the 
esophagus of a patient more easily, while at the same time allowing the 
retaining element to have a greater surface area for contacting the lining 
of the patient's stomach when the gastrostomy tube is in its operative 
position. If the retaining element were to comprise only the petaloid 
flanges it could still pass through the esophagus, but would have a 
smaller contact area with the stomach lining and thus a higher pressure 
per unit of contact area. If the flexibility of the retaining element was 
uniform throughout, the retaining element might not fold over properly or 
might not spring back to being perpendicular to the tubular portion after 
the retaining element leaves the esophagus and enters the stomach. 
In the embodiment illustrated in FIGS. 1-5 the variation in flexibility 
between the petaloid flanges 27, 28, 29 and the connecting portions 30, 
31, 32 is obtained by having the petaloid flanges 27, 28, 29 comprise a 
first material and the connecting portions of the retaining element 
comprise a second material. In the embodiment illustrated in FIGS. 1-5 the 
petaloid flanges are encased in the material which comprises the 
connecting flanges due to a two stage molding process, but the overall 
thickness of the retaining element is substantially uniform. However; it 
is understood the thickness of the petaloid flanges and the connecting 
portions may be substantially the same, or that the connecting portions 
may have a thickness that is less than the thickness of the petaloid 
flanges. 
In the embodiment illustrated in FIGS. 1-5, as well as the embodiment 
illustration in FIGS. 6-9 which will be described later, the petaloid 
flanges of the retaining element are preferably made of a material having 
a durometer in the range of 50 to 80 Shore A, and which is more preferably 
selected from the group consisting of silicone rubbers, polyurethanes and 
polyvinyl chloride. Most preferably the material is a medical grade 
silicone rubber having a Shore A durometer that is in the preferred range 
of 50 to 80. As used herein and in the claims a medical grade material is 
understood to mean a material that is approved by the Food and Drug 
Administration of the Federal Government of The United States of America 
for food contact and meets United States Pharmacopeia (U.S.P) class VI 
testing for bio-compatibility. For example, gastrostomy tubes in 
accordance with the present invention have been manufactured having the 
petaloid flanges of the retaining element comprising Q7-4765 silicone 
Silastic.RTM. Medical Grade ETR Elastomer which is available from Dow 
Corning Corporation. The connecting portions 30, 31, 32 of the retaining 
element of the embodiment illustrated in FIG. 1-5 preferably comprise a 
material having a durometer in the range of 10 to 40 Shore A which is more 
preferably selected from the group consisting of silicone rubbers, 
polyurethanes and polyvinyl chloride. Most preferably the material is a 
medical grade silicone rubber having a durometer that is in the preferred 
range of 10 to 40 Shore A. Preferably, the petaloid flanges of the 
retaining element comprise a material containing barium sulfate in order 
to render this portion of the gastrostomy tube radiopaque so that it will 
show up in an x-ray of the patient. 
It is now believed to be an important feature of a gastrostomy tube 
according to all embodiments the invention described herein that between 
the retaining element 24 and the second end 33 of the tubular portion, in 
other words the second section 36 of the tubular portion, comprises a 
material having a durometer in the range of 30 to 40 Shore A, most 
preferably about 35 Shore A. Preferably this section of the tubular 
portion comprises a material selected from the group consisting of 
silicone rubbers, polyurethanes and polyvinyl chloride. Most preferably 
the material is a medical grade silicone rubber. Preferably this section 
of the tubular portion comprises a material which contains a suitable 
amount (for example 1%) of titanium dioxide as a coloring agent. Inasmuch 
as the petaloid flanges of the retaining element and the tubular portion 
comprise different materials, these components may be attached to one 
another by a suitable adhesive, but preferably are insert molded together. 
An explanation of the criticality of using materials of such varying 
durometer values in the retaining element and the tubular portion has only 
recently been recognized. During about the first fourteen days following 
the insertion of the gastrostomy tube via the Sacks Vine procedure, the 
opening through the patient's abdominal wall has not yet become lined with 
scar tissue. If the patient should pull on the gastrostomy tube with 
sufficient force during this critical scar forming period, the retaining 
element could be pulled through the stomach lining but not through the 
skin, therefor allowing contamination of the peritoneum. Up to a limit, 
the lower durometer material of the tubular portion will dissipate the 
pulling force exerted by the patient, but if this limit is passed by the 
patient pulling excessively hard on the tube the retaining element will be 
pulled completely through to the exterior of the patients skin. However; 
the retaining element does need to be made of a higher durometer material 
so that it will be rigid enough to maintain the tube in place and form a 
seal with the stomach lining under normal circumstances. 
Referring next to FIGS. 6-9 there is shown a gastrostomy tube according to 
a second embodiment of the invention. FIG. 6 is a perspective view; FIG. 7 
is a front elevation view looking in the direction indicated by arrow 7 in 
FIG. 6; FIG. 8 is a side elevation view, partially in section; and FIG. 9 
is a rear elevation view. 
A gastrostomy tube 40 according to this second embodiment is substantially 
like the first embodiment shown in FIGS. 1-5 except for the structure of 
the retaining element 41. That is to say this embodiment has a tubular 
portion 42, and a retaining element 41 comprising petaloid flanges 43, 44, 
45 and connecting portions 46, 47, 48. 
As already stated it is an important feature of a gastrostomy tube 
according to the invention that in the retaining element the petaloid 
flanges are less flexible than the connecting portions. In the embodiment 
illustrated in FIGS. 6-9 the entire retaining element comprises a single 
material, and the necessary variation in flexibility is obtained by the 
connecting portions 46, 47, 48 having a thickness 50 that is less than the 
thickness 51 of the petaloid flanges. Gastrostomy tubes have been 
successfully manufactured wherein the petaloid flanges 43, 44, 45 have 
specified thickness 50 of about 0.2 mm (0.08 inch) and the connecting 
portions 46, 47, 48 have a specified thickness 51 of about 0.5 mm (0.02 
inch), such that the thickness of the petaloid flanges is about four times 
greater than the thickness of the connecting portions. However; it is 
believed that functional gastrostomy tubes may be manufactured wherein the 
thickness of the petaloid flanges is in the range of two times to six 
times greater than the thickness of the connecting portions, depending 
upon the material of which the gastrostomy tube is comprised. In all other 
respects a gastrostomy tube according to this embodiment is substantially 
like the embodiment of FIGS. 1-5. 
In the embodiment illustrated in FIGS. 6-9 the entire retaining element is 
made of a single material having a durometer in the range of 50 to 80 
Shore A, and is selected from the group consisting of silicones, 
polyurethanes and polyvinyl chlorides. Most preferably the material is a 
medical grade silicone rubber having a durometer that is in the preferred 
range and contains barium sulfate in order to render the retaining element 
radiopaque so that it will show in an x-ray of the patient. 
Referring next to FIG. 10, there is shown an assembly comprising a 
gastrostomy tube 55 and a tapered dilator 56. The gastrostomy tube 
illustrated in FIG. 10 is like the embodiment illustrated in FIGS. 6-9, 
but it is understood that a gastrostomy tube according to the embodiment 
shown in FIGS. 1-5 may also be used in the assembly in place thereof. If 
the tubular portion 57 of the gastrostomy tube 55 were to comprise a 
material of sufficient rigidity, it could be configured to function as a 
dilator. However; inasmuch as the preferred materials for the tubular 
portion of the gastrostomy tube are fairly soft and flexible, it is 
preferred that the dilation of the passage through the stomach and 
abdominal wall which is formed by a Seldinger needle during the Sacks-Vine 
procedure is better accomplished by using a tapered dilator 56 of a more 
rigid material. That is to say, the tubular portion 57 of the gastrostomy 
tube 55 should comprise a first material and the tapered dilator 56 should 
comprise a second material, with the first material having a durometer 
that is less than the durometer of the second material. Inasmuch as the 
tubular portion of the gastrostomy tube comprises a material having a 
durometer in the range of 30 to 40 Shore A, it is preferred that the 
tapered dilator comprise a low or medium density polyethylene. As used 
herein and in the claims a low density polyethylene is understood to have 
a density in the range of 0.90 to 0.92 gm/cm.sup.3 and a medium density 
polyethylene is understood to have a density in the range of 0.92 to 0.94 
gm/cm.sup.3. Assemblies have been manufactured wherein the tubular portion 
of the gastrostomy tube is a medical grade silicone rubber and the tapered 
dilator comprises a low or medium density polyethylene. Other materials 
believed to be suitable for the tapered dilator are nylons and 
polyolefins. 
The tapered dilator 56 has first and second ends 58, 59 with a lumen 
extending between the ends of the dilator. The outside diameter of the 
dilator is greater at the first end 58 of the dilator than at the second 
end 59 of the dilator. The first end 58 of the tapered dilator is 
connected by means for connecting 62 to the end 60 of the tubular portion 
57 of the gastrostomy tube that is most distant from the retaining element 
61 of the gastrostomy tube. The means for connecting may be integral to 
the tapered dilator, for example a barbed portion located near the first 
end 58 of the tapered dilator. However; if as in a commercial embodiment 
of the assembly the tubular portion of the gastrostomy tube comprises a 
medical grade silicone rubber and the tapered dilator comprises a low 
density polyethylene, it is preferred that the means for connecting be a 
hollow tubular connector 62 comprising a third material. Satisfactory 
assemblies have been manufactured employing a barbed tubular connector 
made of nylon. The significance of this particular combination of 
materials for the components of the assembly is that it facilitates the 
fastening together of components made of dissimilar materials so that the 
assembly is sufficiently strong and will not separate during the placement 
procedure. 
Referring now to FIGS. 11-13 the function of a gastrostomy tube 66 
according to the invention after it has been placed into a patient can be 
better described. The tubular portion of the gastrostomy tube 66 extends 
via the stoma through the mucosa wall 67, the stomach lining 68, the 
peritoneum 69, the muscle layer 70, the fat layer 71 and the skin 72. The 
retaining member 73 of the gastrostomy tube comes into contact with the 
mucosa wall 67 thereby forming a sealing mechanism for the stoma. A 
retention disk 74 has been slid over the tubular portion of the 
gastrostomy tube to contact the skin 72. Cooperation between the retaining 
member 73 of the gastrostomy tube and the retention disk 74 places the 
proper tension on the gastrostomy tube and reduces the probability of the 
undesirable movement of the gastrostomy tube further into the stomach or 
the unintentional withdrawal of the gastrostomy tube through the stoma. In 
a preferred embodiment the tubular portion of the gastrostomy tube has 
graduations (not shown) on the tubular portion which may be used to 
confirm that the tube has not been displaced. 
As best shown in FIG. 12, wherein the retaining member is shown partially 
in section along line 12--12 of FIG. 11, the flexible nature of the 
retaining element 73 allows it to better conform to the contour of the 
mucosa wall 67, thereby better performing its' sealing function with 
respect to the stoma. 
As shown in FIG. 11-13 the excess length of the gastrostomy tube is cut off 
to form an end 75 which is located about 15 cm from the skin. 
Feeding of the patient may then commence by passing a feeding tube 76 
through the lumen of the gastrostomy tube 66 as shown in FIG. 13. The 
feeding tube shown is of the type commonly known as a jejunal tube. The 
jejunal tube 76 passes through the gastrostomy tube 66 into the stomach 
77, thence through the stomach, past the pylorus and into the small bowel. 
Once in the small bowel, the jejunal tube 76 passes through the duodenum 
78 and preferably terminates in the area of the jejunum 79. Feeding of the 
patient can thereafter be accomplished using procedures that are well 
known in the medical arts. 
While the forms of the apparatus described herein constitute preferred 
embodiments of the invention, it is to be understood that the invention is 
not limited to this precise form of apparatus and that changes may be made 
therein without departing from the scope of the invention as set forth in 
the appended claims.