MXPA00010353A - Stylet for controlled deformation of a tube. - Google Patents

Abstract

A tube and stylet assembly (12) for the controlled deflection of the tube is shown. The stylet (16) is received in the lumen (28) of the tube (14). The stylet includes a first filament (42) having proximal and distal ends and a second filament (44) having proximal and distal ends wherein the proximal and distal ends of the second filament are joined to the first filament such that a surface of the second filament abuts a surface of the first filament. Deflection of the first and second filaments along a plane substantially perpendicular to the abutting surfaces of the first and second filaments necessarily results in a corresponding, opposite deflection of the first and second filaments a spaced distance from the first deflection point. Therefore, a user can control deflection of one portion of the tube and stylet through manipulation of a second portion of the tube and stylet. This structure is particularly useful in inserting a gastric tube either nasally or orally.

Description

STILETTE FOR CONTROLLED DEFORMATION OF A PIPE This application claims the benefit of the United States Provisional Application Serial No. 60/003, 680 filed on September 11, 1995.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates to a hollow tube and, more specifically, to a stylet that can be manipulated to deflect the tube in which the stylet is received. In another aspect, this invention relates to a method for introducing a tube into the patient's stomach through the nose or mouth.

Description of the Related Art In the field of medicine, hollow tubes have numerous applications. For example, hollow tubes can be inserted through a patient's nose or mouth and into their stomach, either to remove fluids and material from it or to provide food or nutrients to the patient. In another application of the tube and stylet assemblies, a tube can be inserted into a patient's nose or mouth to the hole in the trachea to provide oxygen to their lungs. There are many more applications for tubes.

A major problem in the proper insertion of a tube into the patient for the applications described above, is to control the tube during the insertion process. The nasal and oral passages have pronounced curves that hinder the proper insertion of the tube without causing undue trauma to the duct tissue. Attempts to control tube deformation are shown in US Pat. No. 5,259,377 to Schroeder; U.S. Patent No. 4,180,076 to Betancourt; U.S. Patent Nos. 5,195,968 and 5,336,182 to Lundquist et al .; U.S. Patent No. 5,358,478 to Thompson et al .; and U.S. Patent No. 2,574,840 to Pieri et al. Attempts of the prior art have failed to create a stylus that can be controlled in multiple directions and that is easy and simple to manufacture and operate.

COMPENDIUM OF THE INVENTION A tube and stylet assembly specifically useful for inserting a gastric tube by oral or nasal route is shown. The tube and stylet assembly is composed of a tube having a proximal end, a distal end and an intermediate body at the proximal and distant ends. A lumen extends through the tube and a stylet is received telescopically inside it. The stylet consists of a first filament having a proximal end, a distant end and a part of the intermediate body at the proximal and distant ends. The stylet also includes a second filament having a proximal end, a distal end and a part of the intermediate body at the proximal and distant ends. The ends of the second filament are joined to the first filament so that the longitudinal axes of the first and second filaments define a plane. With this structure, the deflection of the stylet in a first direction, practically along the plane, results in a second opposite deviation, corresponding to the stylet along the plane. With this structure, the user can manipulate the tube and stylet to couple them to the intricate curves of the tubes in which the tube and stylet have been inserted, such as the oral or nasal passages, into the stomach.

In a preferred embodiment, the first and second filaments have a substantially planar surface extending longitudinally over a portion of the length thereof. The filaments are joined together, so that the first and second filaments are spliced together. The flat surfaces are adapted to slide one over the other as the stylet deviates along the plane of the curve.

• Preferably, the first and second filaments have a "D" shape in their cross section and the second filament is joined to the first filament by a process such as thermal stacking, welding or adhesive. Alternatively, the stylet can be injection molded or extruded and then slotted along a part of the length of • 10 this to create the first and second filaments from it. Other suitable shapes for the cross section include rectangular, square, triangular, oval, circular and grooved.

In another aspect, the invention is a method for inserting a tube into the patient's stomach by nasal or oral route. The method begins by providing a tube and stylet as described above. The distant end of the tube and stylet are inserted into the nose or mouth 20 of the patient. Then, a part of the stylet that remains outside the patient's nose or mouth is deviated to create a radius of curvature that extends almost along the plane of the curve. This necessarily leads to a corresponding, opposite deviation of the stylet and 25 tube, which are received inside the patient's nasal or oral passages. The parts of the tube and stylet that remain outside the patient are deflected, according to the anatomical curve of the patient's nasal or oral passages, allowing easier insertion. Finally, the tube is received in the stomach of the patient and the stylet is removed from it, so that the tube can be used to remove fluids and material from it or to supply fluids. 10 BRIEF DESCRIPTION OF THE DRAWINGS * Next, the invention is described with reference to the drawings, in which: Figure 1 is a perspective view of a stylus and tube assembly according to the invention; Figure 2. It is a view of a part of the stylet according to the invention and showing the tube with dotted lines; Figure 3 is a cross-sectional view of the stylet and tube assembly taken along lines 3-3 of Figure 1; Figure 4 is a side elevational view of the stylet and tube assembly deformed in a first direction; Figure 5 is a side elevational view of the stylet assembly and tube deformed in a second direction; Figure 6. It is a partial view, sectioned, of the initial stages of the insertion of the gastric tube through the nasal route; Figure 7 is a sectional partial view of the intermediate stage of the insertion of the gastric tube by the nasal route using a stylet according to the invention; Figure 8. It is a sectional partial view of the final stages of the insertion of the gastric tube through the nasal route using a stylet according to the invention; Figure 9. It is a sectional partial view of the intermediate stages of the gastric tube insertion orally using a stylet according to the invention; Figure 10. It is a flowchart of one embodiment of a method for the insertion of a gastric tube by the nasal route using a stylet according to the invention; and Figures 11-16. They show different shapes of the cross section for alternative modalities of the filaments similar to those shown in Figure 3.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Referring to the drawings and Figures 1-5 in detail, a tube and stylet assembly 12 according to the invention is shown. The assembly 12 consists of a flexible tube 14 having a deformable stylet 16 received therein telescopically. The tube 14 consists of a proximal end 20, a distal end 22 and an intermediate body 24 if at the proximal and distal ends. At the proximal end 20 an appropriate conventional luer fitting 26 is provided and 5 is mounted to a mechanism such as a fluid suction or injection apparatus (not shown) depending on the application of the tube 14. A primary lumen 28 extends from the proximal end 20 to the distal end 22 of the tube 14. The mode preferred of the tube 14 further comprises a lumen 10 secondary 30 extending similarly from the proximal end 20 to the distal end 22. The secondary lumen 30 is formed integrated in the tube 14 so that the proximal end of the lumen 30 terminates in a fluid conduit 32 extending out of the tube 14 through an opening 15 appropriate. The fluid conduit 32 has a conventional fitting mounted thereon for connecting the secondary lumen 30 to a suction source, pressurized fluid or other apparatus, depending on the application of the tube 14. Typically, the secondary lumen 30 is included in the 20 gastric tubes. However, this element is by no means a requirement of the invention and a tube having a single lumen is surely within the scope of the present invention. The distal end 22 of the tube 14 terminates at a tip 25 rounded 38 that closes the end of the primary lumen 28.

Most of the openings 40 are formed at the distal end 22 of the tube 14 and provide fluid communication between the primary lumen 28, the secondary lumen 30 and the • outside of the tube 14. The structure of the preferred embodiment of the tube described above is available commercially from Sherwood Medical Co. of St. Louis, MO and is sold under the trademark Salem Sump Tube ™. The stylet 16 consists of a first filament 42 and a second filament 44 joined together. The first filament is 10 comprises a proximal end 46, a distal end 48 and an intermediate body 50 at the proximal and distal ends. Similarly, the second filament 44 is composed of a proximal end 62, a distal end 64, and a body 66 intermediate the proximal and distant ends. From Preferably, the first and second filaments 42, 44 are substantially rectangular in cross section where the first filament 42 has an upper surface 52, a lower surface 54 and a pair of laterally opposed surfaces 56, 58, and the second filament has 20 an upper surface 68, a lower surface 70 and a pair of laterally opposed surfaces 72, 74. As seen in Figure 3, the first and second filaments 42, 44 are dimensioned in such a way that the lower surface 54 of the first filament 42 connects with the 25 upper surface 68 of the second filament 44 and the upper and lateral walls 52, 56, 58 of the first filament 42 and the lower and lateral walls 70, 72, 74 of the second filament 44 are close to the inner surface 34 of the primary lumen 28 5 To the length of the stylet 16. wherein the second filament 44 is mounted to the first filament, it is known as the active part 76 and the rest of the stylet is the static part 78. The proximal and distant ends 62, 64 of the second fP 10 filament 44 are attached to the first filament 42 so that the lower surface 54 of the first filament 42 is very close to the upper surface 68 of the second filament 44. Preferably, the first and second filaments are formed of a plastic material, like acetal or nylon. 15 However, any flexible and durable material will be adequate. If the filaments are formed of nylon, or any other thermoplastic material, then the proximal and distant ends 62, 64 of the second filament 44 can be joined to the first filament 42 by a suitable process such as thermal stacking, ultrasonic welding or adhesive. Otherwise, the filaments may be extruded or injection molded and then partially slotted along the length thereof to create the first and second filaments and the joined proximal and distal ends of the second filament. As can be seen in figures 4 and 5, the tube 14 • is selectively deformed by manipulating the active part 76 of the stylet 16 within the tube 14. The stylet 16 is adapted to allow controlled deformation of a portion of the stylet 16 and the tube 14 in response to manipulation of the second part of the stylet 16 and the tube 14. In other words, the deformation of the stylet 16 and the tube 14 10 adjacent to the proximal end 62 of the second filament 44 leads to a corresponding, opposite deformation of the stylet 16 and the tube 14 adjacent to the distal end 64 of the second filament 44. This action of cause and effect is a result of the attached structure of the first and second 15 filaments 42, 44. As mentioned above, the lower surface 54 of the first filament 42 is preferably spliced to the upper surface 68 of the second filament 44 when the stylet 16 is in a relaxed position, and the proximal and distant ends 62, 64 20 of the second filament 44 are joined to the first filament 42. Therefore, the splicing of the second filament 44 when the first and second filaments are received inside the tube 14 results in a splice corresponding to the first filament 42. If opposing forces are applied to the tube 14 and the 25 stylet 16 in a substantially normal direction to the upper and lower spliced surface 54, 68 of the first and second filaments 42, 44 respectively, then these forces can cause a corresponding deformation of the • stylet 16 and tube 14 around the first radius having a predefined 5 center point. The forces are identified as vectors of forces A and B in Figures 4 and 5. When the first filament 42 is bent around a radius with a center in the force vector A, then the second filament 44 must be deflected in a similar manner because the • 10 ends of the second filament are joined to the first filament. However, the thickness of the two spliced filaments prevents the second filament 44 from rotating about the same radius and center point as the deflection of the first filament 42. In fact, the second filament rotates about a 15 second radio with a second central point. The deviation of the first and second filaments, which are joined, on two different radii of curvature will necessarily lead • to a second deformation of the first and second filaments on two different radii of curvature. The second The deformation is opposite to the first and compensates for the difference in the radii of curvature of the first and second joined filaments 42, 44. As seen in Figure 4, the stylet is deflected by the application of forces in the direction of the vectors. 25 of forces A and B. The deflection of the first filament 42 over a first radius of curvature in the force vector A leads to a second radius of curvature of the second filament 44 in the force vector A. The deflection • opposite, corresponding, of the first and second filaments 5, 42, 44 occurs in a arrow C. The second filament 44 has assumed a radius of curvature in the arrow C which is practically identical to the first radius of curvature of the first filament 42 of the vector of force A. Similarly, the first filament 42 has assumed • 10 a radius of curvature in the arrow C that is practically identical in vector, but opposite in direction, to the second radius of curvature of the second filament 44 in the force vector A. The difference in the radii of curvature between the first and second filaments in the arrows A and C is based 15 mainly in the thickness of the filaments. The variation of the thickness of one or both filaments will lead to a corresponding alteration of the radii of curvature as the filaments deform one with respect to the other along a plane that is practically perpendicular 20 to the spliced surfaces of the two filaments. Figure 4 shows the deflection of the first and second filaments in a first direction along a plane practically perpendicular to the spliced surfaces of the first and second filaments. Figure 5 shows a 25 deviation, similar to the first and second filaments in a second direction along a plane practically perpendicular to the spliced surfaces of the first and second filaments. • According to the invention, the structure of the 5 filaments 42, 44 makes it possible to control the deviation of the distant part of the tube and stylet by manipulating a part of the tube 14 close to the desired deviation point. It is also possible to control the location of the second, opposite deviation, along the active part • 10 of the stylet 16. In general, the center point of the second, opposite deflection will be spaced from the joined distal ends of the first and second filaments 42, 44 a distance that will be equal to the separation of the first deflection of the proximal ends united of the first and second 15 filaments 42, 44. Therefore, if the user wants to create a deviation of the stylet immediately adjacent to the distant tips, then the user will be able to create the • deflection of the stylet 16 immediately adjacent to the proximal ends. Similarly, if the user wants In order to create a wider arc through the distal portion of the stylet 16, then the user will be able to manipulate the proximal portion of the stylet 16 at a further distance from the joined proximal ends. In the preferred embodiment, the end deviation Distant of the stylet 16 is manipulated through the deviation of the proximal end of the second filament 44 and the first filament 42. This particular orientation is the preferred embodiment of the stylet 16. However, the # manipulation of the distant portions of the stiletto 5 to impose the deviation of a part of the stylet next to it, is within the scope of the invention. The ability to control the deformation of the distant end of the tube and stylet assembly by manipulating a part of the tube and separate stylet • 10 approximately the far end, provides some significant advantages when inserting tubes into a contoured hole. For example, an important application of the stylet, according to the invention, is the manipulation of the gastric tube as it is inserted by the 15 oral or nasal. Figures 6-8 show some steps of the insertion of a gastric tube through the nasal route. Figure 10 is a flow chart of the method for inserting the • assembly of tube and stylet 12 by nasal or oral route, according to the invention. From the sectioned views of the patient's anatomy, it is evident that the tube and stylet assembly 12 must be deviated and manipulated significantly along a plane, extending substantially parallel to the longitudinal axis of the patient's neck. Therefore, the The stylet 16 is mounted on the tube 14 so that the plane of the first and second abutting filaments 42, 44 is practically perpendicular to the direction of the required deformation of the tube and stylet assembly 12. As noted • in Figure 6, the process of nasal insertion begins by inserting the rounded tip 38 of tube 14 into the nostril of patient 80. Initially, tube 14 and stylet 16 are inserted practically straight. The distal end 22 of the tube 14 is inserted into the nasal cavity 82 in substantially linear fashion until the rounded tip 38 • 10 approaches the bottom of the nasal cavity 82. Once this step is done, the part of the tube and stylet assembly 14 that remains outside the patient is manipulated to produce a deformation of the distal ends of the filaments and the tube 14 that corresponds to the patient's anatomy. As seen in Figure 7, the outer part of the tube and stylet assembly 12 is deflected near the axis of rotation identified by the force vector A in response to the • Force applied in the direction of force vector B. This deviation of the first filament and the next part of the second 20 filament 44 necessarily leads to a corresponding opposite deviation to the distant parts of the tube 14 and stylet 16 received therein. The proximal portion of the stylet 16 adjacent the nostril 80 deviates near the axis of curvature A. This causes the rounded tip 38 25 of the tube 14 deviates ascendingly within the pharynx, as seen in Figure 7. The deformation of the distal end 22 of the tube 14, as seen in Figure 7, is more easily realized if the user places his finger thumb at the point identified as force vector A and then rotate the proximal part of the tube and stylet assembly 12 over your thumb, resulting in the deviation of the distal end 22 of the tube. With the rounded tip 38 of the tube 14 biased towards the pharynx 84, the tube 14 can be inserted into the nostril 80 until the rounded tip 38 approaches the esophagus 86 and trachea 88. As seen in Figure 8, the outline of the nasal passage will deflect down the rounded tip 38 of the tube 14 so that, with a greater insertion, the tube 14 is received in the esophagus 86, as desired, instead of in the trachea 88. Due to the contour of the cavity nasal 82 and pharynx 84 of the patient, the proximal portion of the active part 76 of the stylet will deviate around a radius of curvature A. This will necessarily force the distal portion 22 of the tube downward, thereby making contact with the bottom surface of the pharynx 84 of the patient. In this position, the tube and stylet assembly 12 can be inserted further, until the distal end 22 of the tube 14 is received in the esophagus 86. Once the distal end 22 has passed the pharynx 84 and the rounded tip 58 is found in esophagus 86, the stylet assembly 12 returns to the relaxed position that allows tube 14 to enter the stomach. Once the tube 14 is properly positioned within the patient's stomach, then the stylet 16 can be removed and an appropriate suction or feeding mechanism can be attached to the luer fitting 26 of the tube 14. In the preferred embodiment, the length of the second filament 44 is dimensioned so that the entire length of the second filament 44 is received within the patient as the distal end 22 of the tube 14 approaches the opening of the esophagus 86. However, it should be understood that the second filament 44 may be dimensioned in any length, dding on the particular application. For example, it may be necessary to extend the length of the second filament 44 so that a portion of the second filament 44 remains outside the patient as the distal end 22 approaches the esophagus 86, so that the user can control the deviation of the distal end. by manual manipulation of the first and second filaments. The preferred embodiment of the tube and stylet assembly 12 is inserted by the nasal route into the patient's stomach. However, as seen in Figure 9, the tube and stylet assembly can also be inserted through the mouth of the patient 90. Similar to the nasal insertion process, the stylet 16 is received in the tube 14 so that the proximal end of the first and second filaments 42, 44 are adjacent the rounded tip 34 of the tube 14. Then, the distal end 22 of the tube 14 is inserted into the mouth of the patient 90 and inserted towards the back from the patient's mouth. As the rounded tip 38 reaches the bottom wall of the patient's pharynx 84, the proximal portion of the second filament 44 and the first filament 42 deviates towards the patient in accordance with the force vectors A and B to generate the upward deflection desired, rounded tip 38. This deflection causes the distal end 22 of the tube 14 to be diverted towards the opening of the esophagus 86. By controlled deviation of the rounded tip, the tube 14 can be manipulated to follow the anatomy of the patient without forcing to tube 14 and stylet towards the oral and nasal passages and thereby reducing trauma to the tissue of the patient's oral or nasal passages. Similar to the process described above, as the rounded tip 38 approaches the opening of the esophagus 86, the proximal portion of the second filament 44 and first filament 42 can be manipulated to guide the rounded tip 38 to the esophagus of patient 86. As described above , the tube 14 and stylet 16 can be inserted into the stomach of the patient by applying the tube. The stylet 16 can be removed from the tube once the tube is properly located in the esophagus 86. Otherwise, he • stylet 16 can be removed after tube 14 is properly positioned in the patient's stomach. By using the stylet 16 according to the invention, a tube 14 can be guided through the contoured ducts by simple manipulation of the tube and stylet. With this structure, now a user can • 10 control the deflection of the tube and insert the tube into a patient more easily, while reducing the trauma to the patient during the insertion process. All this is carried out with an economical and easy to manufacture stiletto. Figures 11-16 show alternative embodiments of the cross-sectional shape of the filaments. Figure 11 shows the prred form of the section • transverse of the filaments 42, 44, that is, in the form of "D". In Figure 12, the cross section of the 20 filaments 142, 144 is triangular. Figure 13 shows the filaments 242, 244 with a rectangular cross section, and in Figure 14, the filaments 342, 344 include a groove 346 and a projection 348 on the spliced faces to ensure adequate sliding movement of the filaments 25 342, 344 one with respect to the other. In Figure 15, the filaments 542, 544 have a square or diamond shape and are oriented so that the pointed corners 546, 548 or the two filaments 542, 544 are joined together. In an alternative embodiment, one of the effective lengths of the filaments 42, 44 may be larger than another, thereby inducing a pre-bend in the stylet. With this structure, the effective length can be manipulated to create the desired flexion by diverting the superimposed filaments. It is possible to make reasonable variations and modifications within the spirit of the aforementioned specification and the drawings without departing from the scope of the invention.

Claims (1)

1. CLAIMS 1. A stylet and tube assembly consisting of: a tube having a proximal end, a distal end, an intermediate body at the proximal and distant ends and a lumen extended therethrough; and a stylet received within the lumen of the tube and consists of: a first filament having a proximal end, a distal end, a part of the intermediate body at the proximal and distant ends and a longitudinal axis; and a second filament having a proximal end, a distal end, a part of the intermediate body at the proximal and distant ends and a longitudinal axis, the proximal and distal ends of the second filament attached to the first filament so that the longitudinal axes of the first filament and second filaments define a plane; wherein the deflection of the stylet substantially along said plane and intermediate to the proximal and distant ends of the second filament results in a corresponding, opposite deviation, substantially along said plane of the intermediate stylet to the proximal and distant ends. 2. The stiletto and tube assembly, according to claim 1, wherein the body of the second filament is almost adjacent to the first filament when the second filament • Strand is in a relaxed condition. 3. The tube and stylet assembly according to claim 1, wherein the first filament has a substantially planar surface extending in the longitudinal direction along the longitudinal part thereof and the second filament having a surface practically • flat 10 extending longitudinally along the longitudinal part of this and the first and second filaments are joined together, so that the flat surfaces of the first and second filament are joined together, the flat surfaces have been adapted for slip one to 15 along another as the stylet is deflected along the plane of curvature. 4. The stylet and tube assembly, according to claim 3, wherein the second filament is substantially rectangular in cross section. 6. The stylet and tube assembly, according to claim 4, wherein the second filament is substantially rectangular in cross section. 6. The stiletto and tube assembly, according to claim 1, wherein the second filament is attached 25 to the first filament by thermal stacking. 7. The stylet and tube assembly, according to claim 1, wherein the second filament is joined to the first filament by welding. 8. The stiletto and tube assembly, according to claim 1, wherein the second filament is attached to the first filament by adhesive. 9. The stiletto and tube assembly, according to claim 1, wherein the proximal and distal ends of the second filament are integrally molded to the first ^ 10 filament. The stylet and tube assembly, according to claim 1, wherein the distal end of the second filament is attached to the distal end of the first filament and the proximal end of the second filament is 15 attached to the first filament at a distance spaced from the proximal end of the first filament. 11. A stylet adapted to the selective deformation of a part of the tube, the stylet is composed of: a first member having a proximal end, a distant end and an intermediate body at the proximal and distant ends; a second member with a proximal end, a distal end and an intermediate body at the proximal and distant ends, the proximal and distal ends of the second member being joined to the first member; wherein a first deflection of the intermediate stylet to the proximal and distal ends of the second member results in a corresponding, opposite deflection of the stylet at a distance spaced from the first deflection. 12. The stylet, according to claim 11, wherein the body of the second member is almost adjacent to the first member when the second member is in a relaxed condition. The stylet, according to claim 11, wherein the first member has a substantially planar surface extending longitudinally along the length portion thereof and a second member having a substantially planar surface extending as far as possible. length of the part of the length of this and the first and second members are joined together so that the flat surfaces of the first and second members are joined together, the flat surfaces have been adapted to slide one along another according to the stylet is deflected between the proximal and distant ends of the second member. The stylet and tube assembly, according to claim 13, wherein the cross section of the second member is substantially rectangular. 15. The stylet and tube assembly, according to claim 14, wherein the cross section of the second filament is substantially rectangular. 16. The stylet and tube assembly, according to claim 11, wherein the proximal and distal ends of the second member are molded in an integrated manner to the first member. 17. A method for inserting a tube into a hole, which consists of the following steps: providing a tube with a proximal end, a distal end and a lumen formed therein; providing a stylet consisting of: a first member with a proximal end, a distal end and a body between the proximal and distant ends and a longitudinal axis; and a second member with a proximal end, a distal end, a body between the proximal and distal ends and a longitudinal axis, the proximal and distal ends of the second member are joined to the first member so that the longitudinal axes of the first and second members they are found along a common plane; insert the stylet into the lumen of the tube; inserting the distal end of the tube into an opening in the hole; diverting the tube and stylet in a first intermediate direction to the proximal and distant ends of the second member, practically along a common plane, resulting in a deflection of the tube and intermediate stylet to the proximal and distal ends of the second member in an opposite direction, at a distance separated from the first deflection, wherein the curvature in the opposite direction corresponds to the curvature necessary to accommodate the contour of the hole. 18. A method for inserting a tube into an orifice, according to claim 17, and further comprising the step of: diverting the tube and stylet at a second intermediate deflection to the proximal and distal ends of the second member, substantially along of a common plane, hereby causing the diversion of the tube and intermediate stylet to the proximal and distant ends of the second member in a third direction, a distance separated from the first deflection, wherein the curvature of the third direction corresponds to the curvature necessary to accommodate the contour of the hole. 19. The method for inserting a tube into an orifice, according to claim 18, and further comprising the step of: removing the stylet from the tube after the tube is in the correct position.