WO1997026845A1

WO1997026845A1 - Method of manufacturing a voice prosthesis

Info

Publication number: WO1997026845A1
Application number: PCT/SE1997/000092
Authority: WO
Inventors: Jan-Ove Persson
Original assignee: Atos Medical Ab
Priority date: 1996-01-24
Filing date: 1997-01-22
Publication date: 1997-07-31
Also published as: SE9600252D0; SE9600252L

Abstract

Method of manufacturing a voice prosthesis to be mounted in a fistula between trachea and esophagus and comprising a spool-shaped body (10) of elastic material with a through passage (10A), and a valve mechanism provided therein, having a seat surface (18) formed by a stiffening ring (14) in the passage and a valve flap (13) engaging the seat surface. The seat ring is inserted into the passage and is engaged with the valve flap which is engaged with bias against the seat surface.

Description

Method of manufac uring a voice prosthesis

The invention relates to a method of manufacturing a voice prosthesis to be mounted in a fistula (passage) between trachea and esophagus .

When a person's larynx has been removed by surgery due to pathological changes in the throat trachea is stitched to an opening in the throat (tracheostoma) . By the surgery the person has lost the ability to speak and in order to restore such ability there is applied for many years a method wherein air is pressed from the lungs via a fistula i.e. a passage between trachea and esophagus through a one-way valve known as a voice prosthesis, into esophagus where the mucous membranes in the throat are made to vibrate and speech is produced as a consequence thereof .

The voice prosthesis comprises a spool-shaped body having a throughpassage and a valve mechanism provided therein said valve mechanism having a seat surface in the passage and a valve flap engaging the seat surface (reference is made to e.g. US-A-4 435 853 and US-A-4 610 691) . If the spool-shaped body consists of an elastic material the seat surface is formed by a stiffening ring in the passage as disclosed in SE-C-463 649.

The valve flap can comprise a separate element which is attached by adhesive to the spool-shaped body (reference is made for example to US-A-4 610 691) or it can be made integral with said body (SE-C-463 649) . At food intake the food will come into contact with the voice prosthesis and then food residues may be deposited between the valve flap and the valve seat. If the closing force is very low and adjacent zero when the prosthesis is closed these food residues cannot be pressed away and it follows that the voice prosthesis will not close completely. At drinking the liquid can then pass through the voice prosthesis and arrive at trachea. This problem will be overcome by allowing the valve flap to engage the valve seat under bias in the closed position of the voice prosthesis, force surplus being available due to the bias tending to close the voice prosthesis also in nearly closed position so that food residues caught between the valve flap and the valve seat in many cases will successively be pressed out instead of keeping the voice prosthesis open and causing leakage. Another problem existing if the valve flap is made of silicone rubber which is the material preferred for this part of the voice prosthesis, is that the material will be successively fatigued during the life of the voice prosthesis . As a consequence thereof the valve flap instead of closing against the valve seat eventually will have a rest position spaced from the seat, causing leakage through the valve prosthesis and thus the need of exchanging the same. Also this problem is overcome by allowing the valve flap to engage the valve seat under bias with following pronounced reduction of the fatigue effect and, as a consequence thereof remarkably increased life.

The invention provides a method of manufacturing a voice prosthesis of the kind referred to above in accor¬ dance with claim 1 by which there can be provided in a sim- pie manner a well balanced bias on the valve flap engaging the valve seat.

In order to explain the invention in more detail two embodiments of the method will be described below reference being made to the accompanying drawings in which FIG. 1 is an exploded axial cross-sectional view of a voice prosthesis constructed for applying one embodi¬ ment of the method of the invention,

FIG. 2 is an axial cross-sectional view of the voice prosthesis manufactured according to this embodiment, FIG. 3 is an exploded cross-sectional view similar to

FIG. 1 of a voice prosthesis for applying the other embodiment, and

FIG. 4 is an axial cross-sectional view similar to FIG. 2 of the voice prosthesis manufactured by the other embodiment of the method according to the invention.

The voice prosthesis disclosed in the drawings com¬ prises in both embodiments (FIGS. 2 and 4, respectively) a spool-shaped body 10 which has two end flanges 11 and 12 and is made of an elastic material, preferably silicon rub¬ ber. It is intended to be mounted in a fistula in the wall between trachea and esophagus with flange 11 engaging the inside surface of trachea and with flange 12 engaging the inside surface of esophagus. The spool-shaped body 10 has a throughcylindrical passage 10A, and in this passage there is provided at the end having flange 12 a valve flap 13 which is made integral with the spool-shaped body and is biased to engage a valve seat formed by a stiffening circu- lar seat ring 14. This seat ring can be made of more or less hard plastic, silicon rubber, or metal and is mounted in a groove 14A in passage 10A. An obliquely cut cylindri¬ cal portion 15 forming an extension of the spool-shaped body 10 projects from flange 12 and protects the valve flap against external influence. A tail 16 projecting from flange 11 is used when mounting the voice prosthesis in the fistula and is then cut off from the voice prosthesis.

The voice prosthesis is principally of the embodiment described in SE-C-463 649. At the manufacture of the voice prosthesis described the method of the invention is applied, which in one em¬ bodiment thereof is illustrated in FIGS. 1 and 2. In this embodiment seat ring 14 has plane parallel end faces 17 and 18 perpendicular to the axis of the ring. One of these end faces, end face 18, shall form the seat surface. The seat ring has at the end where end face 17 is located an inside diameter which corresponds to the diameter of passage 10A and tapers to a slightly smaller diameter at end face 18 forming the seat surface. When the spool-shaped body 10 is moulded valve flap 13 integral therewith is moulded in such a position that it slopes towards passage 10A at an angle to the axis of the passage, said angle being 5 to 30°. Seat ring 14 is then pressed into passage 10A from the end having flange 11, FIG. 1, and is located in the annular groove 14A seat surface 18 being engaged with valve flap 13 which is in a sloping or oblique position and will engage seat surface 18 under bias, FIG. 2. When the seat ring is located in groove 14A the inside surface thereof is flush with the inside surface of passage 10A at the end thereof where end face 17 is located.

When products of silicon rubber are manufactured preferably at least two components are mixed and the mass thus obtained is injected into a moulding tool where the silicon rubber is vulcanised by cross-linking under high pressure and at a temperature ranging from 100 to 200°C. When the vulcanised product is removed from the moulding tool the shape thereof is stable but a number of cross¬ links are still missing. These are produced by a so called second hardening wherein the product is heated in an oven to 150 to 200°C for 3 to 10 hours.

By applying the method of the invention the spool- shaped body 10 can be moulded with valve flap 13 perpendicular to the axial direction of the passage and then be vulcanised with the valve flap in this position. Thereafter, the valve flap is fixed in a tool at an angle of 10 to 50° in relation to the original position and the voice prosthesis is exposed to a second hardening with the valve flap in this position. The valve flap will then be stabilised in a position between the fixed position and the original position by the cross-linking obtained at the second hardening.

In case valve flap 13 is made as an independent part separate from the spool-shaped body, and is attached to said body by means of a projecting tab which is inserted into a slot in body 10 and fixed by gluing to said body, the slot can be arranged in an oblique angle to the axial direction of the body in case the tab is in the same plane as the valve flap, or alternatively the tab can be angled in relation to the valve flap in order to be inserted into a slot which is perpendicular to the axial direction of the body.

In the embodiment according to FIGS. 3 and 4 the voice prosthesis is manufactured with valve flap 13 perpendicular to the axial direction of passage 10A, FIG. 3. In this case seat ring 14 has the end face 17 thereof at right angle to the axial direction of the ring while the other end face 18 forming the seat surface is at an angle of 5 to 30° to the axial direction of the ring. Groove 14A has a corresponding shape as the ring. When ring 14 is pushed through passage 10A to be located in groove 14A valve flap 13 is pushed aside when the oblique seat surface of the seat ring is engaged with the valve flap so that the valve flap angled from the original perpendicular position thereof will be biased to engage the seat surface.

In this embodiment the spool-shaped body 10 is manu¬ factured in a conventional manner with valve flap 13 per¬ pendicular to passage 10A but it is of course possible also in this case to manufacture the valve flap separately with an attachment tab in the same plane as the valve flap which is attached in a slot in the spool-shaped body at said attachment tab, said slot being perpendicular to the axial direction of the body.

Claims

1. Method of manufacturing a voice prosthesis to be mounted in a fistula between trachea and esophagus and com¬ prising a spool-shaped body (10) of elastic material with a throughpassage (10A) and a valve mechanism provided in said passage, having a seat surface (18) formed by a stiffening ring (14) in the passage, and a valve flap (13) engaging the seat surface, c h a r a c t e r i z e d in that the seat ring (14) is introduced into the passage and is engaged with the valve flap (13) while engaging under bias the valve flap against the seat surface (18) .

2. Method according to claim 1, c h a r a c t e r i z e d in that the valve flap (13) is angled to the axial direction of the passage (10A) and by insertion of the seat ring (14) to the predetermined posi¬ tion in the passage is brought to a position substantially perpendicular to the axial direction of the passage with the valve flap (13) engaging under bias the seat surface (18) .

3. Method according to claim 2, c h a r a c t e r i z e d in that the valve flap (13) forms an angle of 5 to 30° with the axial direction of the passage (10A) .

4. Method according to claim 3, c h a r a c t e r i z e d in that the spool-shaped body (10) and the valve flap (13) are made integral of silicon rubber, that the valve flap (13) initially is moulded at right angle to the axial direction of the passage (10A) , that the spool-shaped body with the valve flap is vulcan- ised, and that the spool-shaped body is exposed to a second hardening with the valve flap fixed at an angle of 10 to 50° to the axial direction of the passage.

5. Method according to claim 1, c h a r a c t e r i z e d in that the spool-shaped body (10) is formed with the valve flap (13) perpendicular to the axial direction of the passage (10A) and is angled by engaging a sloping surface (18) on the seat ring (14) with the valve flap at insertion of the seat ring to the prede¬ termined position thereof in the passage in order then to engage under bias the sloping surface of the ring, provided as seat surface.

6. Method according to claim 5, c h a r a c t e r i z e d in that said sloping surface (18) forms an angle of 5 to 30° with the axial direction of the seat ring.