Patent Application
20190336276
The present invention relates to a voice prosthesis having an outer cannula and a removable inner cannula, and in particular to a voice prosthesis having a disposable inner cannula.
When a person's larynx has been removed by surgery due to pathological changes in the throat, the trachea is sutured to an opening in the throat (tracheostoma). By the surgery, the person has lost the ability to speak, and in order to restore this ability to speak a method has been applied for several years, in a voice prosthesis of the kind referred to above is mounted in a fistula, i.e. a passage between trachea and esophagus. At speech, the tracheostoma is occluded by sealing the same either by the patient placing the fingers against the tracheostoma or by the tracheostoma being closed by an in connection there with provided stoma valve. Then, the expiration air is pressed from the lungs through the voice prosthesis into esophagus where the mucous membranes of the throat are brought into vibration and speech is produced as a consequence thereof. Several voice prostheses are described in U.S. Pat. Nos. 4,911,716, 4,435,853, 4,820,304, and DD-AI-275 183. The voice prosthesis is fixed in the fistula by means of two flanges on the spool-shaped element. The spool-shaped element can be cylindrical or oval and preferably it is made of silicon rubber. All existing voice prostheses have in common that they provide a check valve function, which means that the valve mechanism normally is closed but opens when air is pressed from trachea via the valve to esophagus. The valve mechanism is maintained in the closed position by spring bias which in most cases is maintained by elasticity of the material from which the voice prosthesis is made.
When existing voice prostheses are mounted in the fistula the function is acceptable initially but they have a non-acceptably short life due to growth of fungus, Candida, will cover the sealing surfaces of the valve mechanism and causing an obstruction of the valve which causes leakage at the intake of beverages and is the primary reason for exchange of the voice prosthesis. Also, the fatigue of the spring bias (the material of the voice prosthesis) so that the valve as a consequence thereof will be partly open in the normal position causing leakage through the voice prosthesis.
The following are of interest: U.S. Pat. Nos. 3,693,624; 4,315,505; 5,314,470; 5,578,083; 7,166,128. No representation is intended by this listing that a thorough search of material prior art has been conducted, or that no better art than listed is available.
As mentioned above the growth of Candida on the sealing surfaces of the voice prosthesis is the main reason for the necessity of exchanging the voice prosthesis. It is an object of the present invention to provide a voice prostheses with outer cannula, which remains in place mounted in the fistula, and a removable, disposable, and inexpensive inner cannula, which serves as an inner lining of the outer cannula and contains said valve mechanism. Thus, to clear the growth of fungus, Candida, covering the sealing surfaces of the valve mechanism and causing an obstruction of the valve passage way, the inner cannula can be removed, cleaned, or disposed of and then replaced. An important feature of the inner cannula of the present invention, is its disposability. The inner cannula can be quickly and easily produced in large quantities using an extruded molding process and then end-formed to create the flange at the proximal end using a heating process. Furthermore, dimensional tolerances are held close only in the distal area of the inner cannula to assure an adequate seal with the outer cannula.
Further advantageous features of the invention are defined in the dependent claims.
Referring to all FIGS. there is shown the voice prosthesis unit of the present invention, including a tubular outer cannula 10 made of a silicone rubber or a thermal plastic elastomer and a removable tubular inner cannula 11 made of a rigid plastic material, shown removed in
The outer cannula 10 is for insertion into the fistula, i.e. a passage between trachea and esophagus of the patient through an opening in the neck and has a flange and opening at both distal and proximal ends.
The inner cannula 11 is inserted into the proximal opening of the outer cannula 10 and secured in place by means of a coupling feature located on its proximal end as shown in
The outer cannula 10 is made of a compliant material such as silicone rubber or a thermal plastic elastomer material and therefore the retaining nubs 14 of the outer cannula 10 are compliant and will move out of the way as the rigid plastic inner cannula 11 is inserted. The inner cannula 11 has windows 13 that when placed in the desired position within the outer cannula 10 will allow the nubs 14 to spring back into its molded shape. Further the outer cannula has a reduced diameter portion 15 near its esophageal end as shown in
The inner cannula 11 forms a passageway to permit air to flow from the trachea into the esophagus.
Mounted and located just at the distal end behind the tip of the inner cannula 11 is a flap valve 12.
An important feature of the inner cannula 11 of the present invention, is its disposability, it is relative in expense associated with the polymer materials and methods of manufacture from which it is constructed. For example, the inner cannula 11 can be quickly and easily produced in large quantities using an injection molding or extrusion molding process and then end-formed to create the flange at the proximal end using a heating and forming process.
Furthermore, dimensional tolerances are held close only in the distal area of the inner cannula 11 and outer cannula 10 to assure an adequate seal. This provides for ease of insertion of the inner cannula 11 into the outer cannula 10 and interchangeability of the inner cannula 11.
Furthermore, as described above, these inner cannulas 11 are sufficiently economical in terms of material and manufacturing cost to make their disposability practical. The inner cannula 11 with incorporated flap valve 12 can be removed, cleaned, or disposed of making it easy to replace when in case of an obstructed flap valve 12. Thus, adding to the longevity of the outer cannula 10 and reducing the frequency of replacement needed.
