Abstract:
An instrument for grasping securely an aural ventilation tube whilst simultaneously presenting the device at the correct angle for the insertion of an aural ventilation tube. The instrument prevents a rotation of the aural ventilation tube during the insertion procedure. 
     The instrument is able to be passed from one medical practitioner to another during the procedure.

Description:
The Universal Aural Grommet Inserter is utilised to insert transtympanic aural grommets in an ear to ventilate the middle ear and relieve pain and infection. 
     There are a multitude of varying designs of aural ventilation tube and this new Universal Aural Grommet Inserter is designed to enable a competent medical practitioner to insert most types of aural ventilation tube within an ear. 
     The device is similar in appearance to a commonly utilised instrument with which all Ear, Nose and Throat Surgeons are familiar, namely a suction tube hand-piece. The device is intended to be single use and is operated by a slide control on the hand-piece of the Universal Aural Grommet Inserter. The slide control is intended to advance and retract a 0.5 mm curved stainless steel wire to grasp and release the aural grommets. The use of this device will obviate the need for conventional forceps and ensure optimum grasping angle for presentation of the aural grommet to the ear drum. 
     BACKGROUND TO THE INVENTION 
     An aural ventilation tube can take many forms but it is intended to be inserted into the human ear drum for the purpose of ventilating the middle ear cleft. In short, it maintains an airway between the middle ear and the external ear canal. It may be called a ‘drain’, which is a misnomer; a ‘vent tube’; a ‘p.e. (pressure equalization) tube’ or a ‘grommet’. 
     Aural ventilation tubes/grommets are normally inserted with surgical alligator forceps (see FIG.  1 ). Especially designed inserters have been used, which transport the ventilation tube/grommet by means of a metal pin (see FIG.  2 ), having an interference fit with the lumen or bore, i.e. the internal diameter of the tube. Once in situ, the pin is withdrawn from the lumen into a tube, the distal end of which, pressing against the outer flange of the grommet, thereby prevents its dislodgement from the incision in the ear drum, so leaving the ventilation tube/grommet in situ. 
     The ear drum closes the external ear canal, forming a beveled end to the canal. Existing inserters, which fit the internal diameter of the vent tube, are rarely used because they present the leading or inner flange of the ventilation tube/grommet to the ear drum at the wrong angle, which means that it is difficult or, for some clinicians, impossible to locate the device across the ear drum, owing to the length of the narrow, external ear canal, which severely limits the surgeon&#39;s ability to manipulate the grommet into the incision in the ear drum. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the invention is to provide a convenient and economic method by which to insert an aural ventilation tube/grommet. The invention constitutes a more secure, stable and hygienic means of transporting and inserting an aural grommet, whilst improving the ergonomics of the procedure. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 Micro Alligator Forceps holding Shah type aural ventilation tube. (Prior Art) 
     FIG. 2 Scissor action piston type aural ventilation tube inserter holding a Shah type aural ventilation tube. (Prior Art) 
     FIG. 3 Cross section of Universal Aural Ventilation Tube/Grommet Inserter with enlarged detail. 
     FIG. 4 Perspective view of Universal Aural Ventilation Tube/Grommet Insertion Instrument with enlarged detail of jaws and Shah type ventilation tube/grommet. 
     FIG. 5 Plan view of Universal Aural Ventilation Tube Insertion Device. 
     FIG. 6 Side elevation and cross section of a typical aural ventilation tube/grommet (Shepards Drain). 
     FIG. 7 Plan view of inner flange of aural ventilation tube (Shah) and cross section of aural ventilation tube (Shah). 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention comprises a universal ventilation tube/aural grommet insertion instrument (FIG. 5) used for the placement of a ventilation tube/aural grommet  11  across the tympanic membrane transtympanic placement. 
     The invention takes the form of a micro-bore tube  1  for which a weld-free, stainless steel tube  1  of 18 s.w.g. (1.24 mm outside diameter) is preferred, although other validated, rigid materials and similar dimensions would be suitable. A handle  2  is moulded to the tube  1  manufactured from blue, high density polyethylene, which facilitates the surgeon&#39;s firm grip on the instrument (FIG.  4 ), but the colour, shape, size and material content of the handle  2  may be changed without affecting the instrument&#39;s (FIG. 4) characteristics significantly, providing that they afford a firm grasp for the surge on and prevent the tube  1  from rotating within the handle  2 . 
     The tube  1  is bent or curved  3  at a preferred distance of approximately 60 mm from its distal end  4  sufficient to allow a clear line of sight along the tube  1  at its distal end  4  without obstruction to that view from the hand of the us er. 
     A piston  5  is located within the tube, which projects from the distal end  4 . This piston  5  may be made of any rigid validated material and may be solid or hollow. For this purpose, however, stainless steel wire  5  of 0.5 mm diameter has been preferred. At its proximal end  6 , which is within the handle, this wire piston  5  is connected to a finger-operated slide  7 . The slide  7  moves forwards and backwards within a supporting recess  8  in the plastic handle  2  of the instrument, which breaches the stainless steel tube  1  within it, forming a slot in that tube  1 . This allows the slide  7  and wire  5  which comprise the piston assembly  9 , which includes  5 ,  6 ,  7  and  10 , to move backwards and forwards. The slide component  7  is made of blue, high density polyethylene but could be made of any other validated rigid material. A hole  10  through that slide component  7 , perpendicular to the axis of the tube  1 , accepts and traps the wire piston  5 , which is bent and folded on itself but which, springing apart, within the hole  10  through the slide component  7 , makes a positive connection between the slide  7  and the piston  5  (see FIG.  3 ). 
     With the slide  7  pushed forward, the wire piston  5  protruding from the distal end  4  is cut to length, according to the dimensions of the ventilation tube/grommet to be inserted by the instrument (FIG.  4 ). In the case of this instrument (FIG.  4 ), that projection is between 1.7 mm and 1.8 mm from the distal end  4  of the tube  1 , when fully advanced. These dimensions may vary according to the pattern of aural ventilation tube/grommet  11  to be inserted. 
     Any other mechanical design for advancing and withdrawing the piston by single-handed movement would be equally satisfactory. 
     The distal end  4  of the instrument (FIG. 4) is ground away  12  to enable it to be angled to a preferred 45° or similar angle. The shape of this angled protrusion  15  will have a radius  18  to accommodate the outer flange  19  of any aural ventilation tube/grommet  11 . 
     The method for inserting the ventilation tube/grommet  11  is as follows. The surgeon or clinical assistant holds the inserter (FIG. 4) in one hand and manually advances the piston assembly  9  by using a forefinger to press the slide component  7  forward towards the distal end  4  of the instrument. The projecting piston  5  is then fully introduced into the lumen  13  of the ventilation tube/grommet  11 . With the piston assembly  9  free to move, the ventilation tube/grommet  11  is grasped between the angled distal end of the tube  18  and the angled distal end of the piston wire  5 , when it is retracted so that the immobile jaw  18  of the grasping mechanism (FIG. 3) comes to rest against the annulus  16  of the external flange  19  of the ventilation tube/grommet  11  and the other mobile jaw  5  comes to rest against the internal surface  17  of the external flange  19  of the ventilation tube/grommet  11  (see FIG.  3 ). 
     The piston  5  of the instrument (FIG. 4) makes a secure fit within the external flange  19  of the ventilation tube/grommet  11 . The registration of the external flange  19  of the ventilation tube/grommet  11  against the immobile jaw  18  of the instrument (FIG. 4) assures that the ventilation tube/grommet  11  cannot rotate during its introduction into the incision in the ear drum. 
     When the inner flange  20  of the ventilation tube/grommet  11  has been introduced into the incision, the surgeon holds the instrument (FIG. 4) still while manually advancing the piston assembly  9  and, by that means, the piston  5  from the lumen  13  of the ventilation tube/grommet  11 . This releases the grip of the ventilation tube/grommet  11 , leaving it lying partially within the incision in the ear drum. Gentle pressure on the visible part of the inner flange  20  forces the ventilation tube/grommet  11  into position across the ear drum, thereby completing the insertion procedure.