Intra-aural device for alleviating symptoms of TMJ disorders

Abstract

An ear insert device 10 for alleviating symptoms of TMJ disorders comprises an elongate body, e.g. hollow tube, of substantially rigid material configured to match or correspond to the internal shape

Description

TECHNICAL FIELD This invention relates to a medical device, more particularly to an intra-aural device for alleviating symptoms of temporomandibular joint (TMJ) disorders. More particularly, the invention relates to a method for making such a medical device, in particular an intra-aural device for alleviating pain and / or discomfort caused by various TMJ disorders. The invention also provides such an intra-aural device made by the method, and also to a method for alleviating pain and / or discomfort caused by a TMJ disorder by use of the intra-aural device. BACKGROUND OF THE INVENTION AND PRIOR ART Temporomandibular joint disorders (TMJDs) comprise a range of conditions and symptom sets that affect the TMJ and associated soft tissues, including (but not limited to) the muscles of mastication, the articular disc, associated ligaments, and the auriculotemporal and masseteric branches of the trigeminal nerve. The most commonly occurring TMJ-related disorders are myofascial pain dysfunction syndrome or myalgia, internal derangements of the articular disc and arthralgia. It has been demonstrated that some 25% of the population will experience TMJD-related issues at some point in their lives, and this has been shown to be higher in certain demographics. Current guidelines for treating TMJDs comprise a first line of conservative treatment modalities, including (but not limited to) behavioural management, physiotherapy, jaw exercises, and treatment regimens involving administration of NSAIDs or muscle relaxing medications. However, some of these medications involve controlled drugs that may be addictive and are not advised for long term use. Application of heat has also been shown to have a positive effect on some TMJD symptoms. Occlusal splint therapy has also been effectively used to help combat the symptoms of TMJDs. These include soft splints, hard splints, NTI-tss (nociceptive trigeminal inhibition tension suppression system) type splints and other anterior repositioning splints. However, not all patients can tolerate splints during sleep and wearing them during the daytime sometimes poses insurmountable problems with hyper-salivation, speech interference and the impediment of other oral functions. Along with this it has been demonstrated that the prolonged use of occlusion splints can result in unwanted changes in occlusion. If this initial first line of conservative treatment modalities fails to remedy the symptoms associated with TMJDs, then more invasive techniques can be employed, including arthroscopy, lavage and sometimes even TMJ replacement. This places a high biological cost on the patient and there is also a high financial burden associated with these more invasive therapies. It is well-known that there is a close anatomical association between the TMJ and the ear canal. The TMJ is a bilateral set of sliding hinge joints with an articular disc sitting between the condylar head and the glenoid fossa of the temporal bone. Although the joint is bilateral, the function is also bilateral, thus resulting generally in a single functioning unit. The joint has an articular disc separating the head of the condyle from the temporal bone and is surrounded by an articular capsule of dense fibrous tissue. The articular disc is an extension of the fibrous capsule which separates the joint capsule. The anterior ligament of the articular disc inserts into the superior head of the lateral pterygoid. The posterior disc and joint capsule are intimately connected with the retrodiscal tissue which in turn is intimately connected with the anterior aspect of the ear canal. The TMJ function is anatomically unique in that it comprises a rotational movement and also a translation. As the mandible opens in function, the condylar head rotates in a hinge-like motion and then translates forward along the articular eminence. Contraction of the inferior head of the lateral pterygoid plays a pivotal role in mandibular depression, and this contraction also aids in the anterior movement of the articular disc. With this translational movement of the joint and anterior movement of the disc comes an associated anterior displacement of the posterior joint capsule, retrodiscal tissues and pivotally also the ear canal. As a result, during mandibular depression the ear canal is expanded in size as it is pulled anteriorly by the insertions of the retrodiscal tissues which in turn are moved anteriorly by the contraction of the inferior head of the lateral pterygoid muscle. This expansion is typically an increase in size of approximately 22-25%. Conversely, the ear canal reduces in size with mandibular elevation, whereupon the soft retrodiscal tissues are compressed. Pain and / or discomfort from disorders of the TMJ are often multifactorial. For example, myalgia can come from para-functional habits and high occlusal forces. For example, disc derangement can occur when the articular disc moves from its normal position between the head of the condyle and the temporal bone, resulting in painful eburnation. Discomfort or pain (e.g. headache, neck ache, myospasm, arthralgia or myalgia), or possibly in some cases even muscular hypertrophy, can also originate from abnormal stresses on the ligaments of the articular disc or on the muscles of mastication, as well as from abnormal pressures placed on other components of the TMJ, in particular the retrodiscal tissues, the condylar head, the temporal bone, the articular disc and capsule itself, and various of the associated nerves. Hitherto certain devices have been proposed for placement within the ear canal for the purpose of treating pain or discomfort associated with various TMJDs. Examples of these known devices are disclosed for instance in EP0998243B1 and EP2262446B1. They take the form of a hollow, generally cylindrical support body of rigid material which is shaped to conform to the ear canal’s internal shape in its intended region of placement therein, which is between its entrance and the isthmus, and once they have been so inserted at their intended site their purpose is to act on the TMJ and associated ligaments and muscles to reduce stresses and loads placed on the articular disc, the supportive muscles and ligaments and the associated nerves adjacent the TMJ. However, these known devices are at best only a partial solution to the problem of treating pain / discomfort symptoms of TMJDs. In particular, these known devices provide only limited efficacy in relieving pain or discomfort associated with TMJDs, and they also provide only limited degrees of comfort, stability and aesthetics. Furthermore, owing to their method of production using conventional moulding techniques, they are only able to provide limited accuracy in matching the ear canal’s internal shape, which further detracts from optimum efficacy, comfort, stability and aesthetics. It is therefore a primary object of the present invention to address the above shortcomings of known intra-aural devices for the alleviation of symptoms of TMJDs, and to provide a new design of intra-aural device for this purpose which may provide improved levels of relief of pain and / or discomfort arising from TMJDs, as well as improved degrees of comfort, stability and aesthetics. SUMMARY OF THE INVENTION Accordingly, in a first aspect the present invention provides a method for making a device for insertion into an ear canal of a human subject to alleviate symptoms of temporomandibular joint (TMJ) disorders thereof, the subject’s ear canal including an entrance, a first bend, an isthmus and a second bend, wherein the method comprises: (i) making, by means of (a) making a 3D scanning image, or (b) making a 3D moulded impression, or (c) a combination of (b) and (a), a three-dimensional model of the internal shape of at least a section of the subject’s ear canal extending from (A) a site within the subject’s ear canal which lies distally spaced from (i.e. spaced in a distal direction from, and measured in the longitudinal direction of the ear canal) the subject’s ear canal’s entrance by a distance of from 1 up to 7 mm, and to (B) a site within the subject’s ear canal which is within a distance (measured in the longitudinal direction of the ear canal) of up to 4 mm proximally short of the second bend or up to 4 mm distally beyond the second bend, when the subject’s jaw is in an open position; and (ii) producing an elongate body of substantially rigid material exteriorly shaped and configured to substantially match the exterior shape of the three-dimensional model of the said section of the subject’s ear canal made in step (i), to form the said device for insertion into the said section of the subject’s ear canal; wherein the production step (ii) is carried out using a 3D printing technique. The present invention further provides a device for insertion into an ear canal of a human subject to alleviate symptoms of temporomandibular joint (TMJ) disorders thereof, the device being made by the method of the first aspect of the invention or any embodiment thereof The present invention further provides a method for alleviating pain and / or discomfort caused by a TMJ disorder, the method comprising: (i) providing a device made according to the method of the first aspect of the invention or any embodiment thereof; and (ii) inserting the said device into the ear canal of the subject so as to be located in the defined section thereof. In practising many embodiments of the invention, it is to be understood that the feature of the device being configured so as to be insertable into the ear canal of the subject and locatable in the defined section thereof, may be particularly useful for enhancing the degrees of comfort of wear and aesthetics experienced by a wearer of the device once it has been inserted into its intended placement location in the wearer’s ear canal. In practising embodiments of the invention, the ear canal is an ear canal of a human subject who suffers from pain or discomfort as a result of a TMJ disorder. As used herein, the term “proximal”, as referring to the end of the device that is locatable or located in a portion of the ear canal inwardly spaced from the ear canal’s entrance, means that end of the device which is designed to be closest to the ear canal’s entrance when the device is in position inserted therein. Correspondingly, as used herein, the term “distal”, as referring to the other end of the device, i.e. that end opposite the first-mentioned end which is locatable or located closest to the ear canal’s entrance, means that end of the device which is designed to be remotest from the ear canal’s entrance when the device is in position inserted therein and thus the end that is designed to be closest to the second bend of the ear canal when the device is in position inserted therein. Similarly, as used herein, the terms “proximal” and “distal”, as referring to ends or portions or regions of the ear canal itself, or directions along the longitudinal length of the ear canal, refer to those respective ends, portions or regions of, or directions along, the ear canal which are, respectively, nearest to and remotest from the ear canal’s entrance. Thus, in embodiments of the device made according to the invention, in addition to the device being configured so as to be insertable into the ear canal and locatable therein such that a proximal end of the device is located in a portion of the ear canal inwardly spaced from (i.e. spaced in a distal direction from) the ear canal’s entrance, the device is further configured such that, when it is so located in the ear canal, a distal end of the device is located in a portion of the ear canal at or adjacent or in the vicinity of the second bend. Therefore the elongate body of the device is configured so as to substantially match or correspond to the internal shape of the defined section of the ear canal extending from proximal its entrance and to or adjacent or in the vicinity of the second bend, when the jaw is in an open position. In some embodiments of the method of the invention, the step (ii) may be a step of producing an elongate body of substantially rigid material exteriorly configured so as to substantially match or correspond to the exterior shape of the three-dimensional model of the defined section of the subject’s ear canal made in step (i) of the method, which may constitute approximately or substantially the full extent of the three-dimensional model made in step (i) of the method. In many practical forms of the above-defined method for alleviating pain and / or discomfort caused by a TMJ disorder, therefore, the device that is provided and made according to the defined method may be a device which, in addition to it being configured so as to be insertable into the subject’s ear canal and locatable therein such that a proximal end of the device is located in a portion of the ear canal inwardly spaced from (i.e. spaced in a distal direction from) the ear canal’s entrance, it is further configured such that, when it is so located in the ear canal, a distal end of the device is located in a portion of the ear canal at or adjacent or in the vicinity of the second bend, when the jaw is in an open position. In accordance with embodiments of the invention in its various aspects, the device made by the method is configured so as to be locatable in the ear canal such that, once inserted therein, the proximal end of the device is located at a site within the ear canal which lies significantly distally (or inwardly) spaced from (i.e. spaced in a distal direction from) the ear canal’s entrance, which is to say at a site within the ear canal which lies distally (or inwardly) spaced from (i.e. spaced in a distal direction from, and measured in the longitudinal direction of the ear canal) the ear canal’s entrance by a distance of from about 1 up to about 7 mm, especially from about 2 or 3 up to about 4 or 5 or 6 mm, or more especially at a site within the ear canal which lies distally (or inwardly) spaced from (i.e. spaced in a distal direction from, and measured in the longitudinal direction of the ear canal) the ear canal’s entrance by a distance of from about 2 up to about 5 mm. In some embodiments of the invention in its various aspects, the device made by the method may be configured so as to be locatable in the ear canal such that, once inserted therein, the distal end of the device is located at a site within the ear canal which is either (i) substantially at the second bend thereof, or (ii) adjacent or in the vicinity of the second bend, which is to say at a site which is within a distance (measured in the longitudinal direction of the ear canal) of up to about 4 mm, or perhaps up to about 1 or 2 or 3 mm, proximally short of the second bend, or up to about 4 mm, or perhaps up to about 1 or 2 or 3 mm, distally beyond the second bend, when the jaw is in an open position. In such embodiments this extending of the longitudinal length of the device, by virtue of the longitudinal extent of its distal end relative to the remainder of the device body, into the ear canal at least as far as the second bend of the ear canal, may be particularly useful in enhancing the degree of anchoring and stability of the device once inserted into its intended placement location in the ear canal. This feature may be especially useful in enhancing the degree of the device’s stable retention at its intended location or site once it has been so inserted into the ear canal. It is to be understood that, in any given practical embodiment device, the precise optimum distance defined in the preceding paragraph - by which the site of location of the distal end of the device may fall just short of or extend just beyond the second bend of the ear canal -may depend on e.g. the size and length of the person’s ear canal, their body size, age, or even other anatomical factors that dictate the person’s unique ear canal geometry. In some embodiments of the invention in its various aspects, the device made by the method may be configured so as to be locatable in the ear canal such that, once inserted therein, the distal end of the device is located at a site within the ear canal which lies significantly distally (or inwardly) beyond (i.e. beyond in a distal direction) the isthmus (or isthmus portion) of the ear canal, especially at a site within the ear canal which lies distally (or inwardly) beyond (i.e. beyond in a distal direction, and measured in the longitudinal direction of the ear canal) the isthmus (or isthmus portion) of the ear canal by a distance of at least about 2 mm, or perhaps at least about 3 or 4 or 5 mm, when the jaw is in an open position In some embodiments of the device made by the method of the invention, the body of substantially rigid material that forms the device may be generally elongated with at least one longitudinal internal bore or channel formed through the body, whereby the body is tubular and substantially hollow throughout its longitudinal length. This feature of such embodiments may facilitate the passage of sound waves through the device and reaching the eardrum at the distal end of the ear canal of a person wearing the device, in order to, as far as is reasonably possible, not unduly occlude or impair the person’s sense of hearing. In some such embodiments, the body may thus be formed as a hollow tubular structure, with sidewalls having a thickness that enables the device body to substantially hold its substantially rigid shape. By way of example, in many practical embodiments the walls of the tubular device may typically be of a thickness in the range of from about 1 to about 2 mm. In some such hollow tubular embodiments, the wall thickness may be substantially uniform or constant along the length of the device, moving along its tubular length. However, in other, possibly more desirable, hollow tubular embodiments, the wall thickness may vary along the length of the device, for example ranging from about 1 mm at the proximal end of the device and increasing in thickness to about 2 mm at the distal end of the device. This gradual thinning of the tubular structure’s walls moving from its distal to its proximal ends may help to improve the comfort of wear of the device and also help to reduce its occlusion effect in the ear canal. In practical embodiments of the invention, the material of the body may be any suitable material able to substantially hold its exterior substantially rigid shape when formed into the body, especially in the case of hollow / tubular embodiments with the body’s sidewalls being of optimal thickness to allow accommodation and maintenance in an open condition of the above-mentioned internal bore or channel within the body. Examples of suitable materials for use in making the body of the device may include various polymers or plastics materials that are able to adopt and hold substantially rigid configurations when formed into the relevant shaped bodies, especially tubular or hollow bodies, e.g. a polyacrylate polymer. Various other examples of suitable polymers may also be used and be readily available. However, in other embodiments of the invention, the body of substantially rigid material that forms the device may be generally elongated but formed with a substantially solid or continuous internal structure, or possibly even a porous or closed- or open-cell internal structure, throughout its internal diameter or width. Thus, such a body may be without any continuous longitudinal internal bore or channel formed therethrough. This feature of such embodiments may thus find use for noise- or sound-occlusion or cancellation purposes or hearing protection, e.g. in the case of a person in need thereof or where such an auxiliary purpose may be desirable or wanted. It may further be the case, in certain yet other embodiments, that in either the above-defined hollow / tubular embodiment device or the above-defined solid / continuous embodiment device the relevant body may be formed or provided with a sound reproduction device, such as an earphone or loudspeaker, mounted therein, in order to provide an earpiece- or “earbud”-type device for the listening to of music, spoken words or other audio content or for telecommunications purposes (e.g. in combination with a mobile phone or other mobile device). In accordance with the invention, the body of substantially rigid material that forms the device is elongate and configured so as to substantially match or correspond to the internal shape of a section of the ear canal extending from proximal its entrance and to or adjacent to the second bend, when the jaw is in an open position, especially when the jaw is open at a set or predefined inter-incisal distance (which distance may depend on the patient or subject’s overall anatomical dimensions in the vicinity of their TMJ and ear canal). Thus, in some practical embodiments of the invention the body that forms the device may be exteriorly configured such that it has a generally convoluted asymmetrical external shape which generally substantially matches or corresponds to the internal shape of at least that section of the ear canal extending from proximal its entrance and at least as far as, or at least to adjacent or to in the vicinity of, or possibly even to just internally beyond, the second bend, when the jaw is in an open position. It is therefore to be understood that the external diameter or width of the body forming the device may vary passing longitudinally along it, depending on the internal dimensions and geometry of the person’s ear canal into which the device is intended to be inserted for use, and also e.g. depending on the person’s body size, age, as well as possibly other anatomical factors. In particular, in some embodiments of the invention the device may comprise at least one portion which is shaped so as to include a narrowing tapering in the body’s external diameter or width passing longitudinally along that portion of the body in a distal direction, which portion may be a proximal portion of the device body in the vicinity of a proximal end thereof. Such a proximal portion may commence at or adjacent or in the vicinity of the proximal end of the device, e.g. it may commence within about 0 or 0.5 or 1 or 2 or 3 or 4 mm from the proximal end of the device, and may taper with a general narrowing in the body’s external diameter or width passing longitudinally along that portion of the body in a direction towards its opposite, distal end. Such a feature may be useful for helping to improve the comfort of wear of the device. Likewise, it is also to be understood that the overall longitudinal length of the body forming the device may also vary depending on the longitudinal length of the relevant section of the person’s ear canal into which the device is intended to be inserted and placed for use, e.g. and again depending on their body size, age, as well as possibly other anatomical factors. It is to be understood that the precise dimensions of the ear canal of any given person, when their jaw is in an open position, may vary to some extent, e.g. depending on their body size, age, or possibly other anatomical factors that dictate the person’s unique ear canal geometry. Thus, in practical implementations of embodiments of the invention it may generally be the case that the degree to which the body of substantially rigid material that forms the device is elongate and configured so as to substantially match or correspond to the internal shape of the desired section of the ear canal is designed to be as close a fit or match as is reasonably possible, e.g. within the constraints of the manufacturing process and the degree to which the dimensions and geometry of the intended wearer’s ear canal, when their jaw is in the open position, can be accurately be defined and / or measured. Likewise the precise longitudinal length of the device that allows its proximal to be located in a portion of the ear canal inwardly spaced from (i.e. spaced in a distal direction from) the ear canal’s entrance, and its distal end to extend into the ear canal at least as far as the vicinity of or adjacent to the second bend, may also vary slightly or somewhat from patient / subject to patient / subject, and so for any given patient / subject that longitudinal length of device that enables that correct site of placement of the device’s proximal and / or distal end(s) may be individualised, although the respective anatomical landmark(s) will be consistent for all patients / subjects. In some embodiments of the invention, the device may be provided with means, especially manually graspable means, for aiding its removal from the ear canal, e.g. when it is desired to remove it for any reason or to replace it. Such means may for example comprise a tab, pin, leg, arm, or other extension or protrusion extending from (and e.g. formed integrally with) a portion of the body of the device at or adjacent or in the vicinity of its proximal end, or alternatively such means may comprise a cord, string, wire or other elongate member attached to that portion of the body of the device at or adjacent or in the vicinity of its proximal end. Such removal-aiding means may extend from, or be attached to, the body of the device at any suitable point, region or location thereon, e.g. from a location midway along (and optionally slightly distally displaced from (e.g. spaced by up to about 1 or 2 or 3 mm from)) a proximal edge or lip or mouth of the device body at its proximal end. In some further embodiments of the device made using the invention, as an alternative to or an addition to the above feature of primary removal-aiding means, especially that being of the nature of a manually graspable cord, string, wire or other elongate member, there may be provided an auxiliary removal-aiding means, for aiding the device’s removal from the ear canal, e.g. when it is desired to remove it for any reason or to replace it, especially when the aforementioned primary removal-aiding means is damaged or has become detached. Such auxiliary removal-aiding means may comprise a through-hole or aperture formed in a wall or sidewall (the latter particularly in the case of a hollow tubular body embodiment) of the device, for use with a tool (e.g. a wax hook) to manually remove or extract the device from the ear canal if / as or when required. Such a through-hole or aperture, which may typically be a small circular or elliptical (or other suitably shaped) hole / aperture e.g. of around 2 mm across / in diameter, may be formed at any suitable location in the vicinity of or adjacent the proximal end of the device body, especially a short distance in from the peripheral edge of the device body’s proximal end. The location of the through-hole or aperture may usefully be on that side of the device which is closest to, or in the vicinity of or adjacent, the tragus of the outer ear when the device is in position in the ear canal. In some embodiments of the device made using the invention, in order to further aid its retention or stability in the ear canal once inserted therein into its desired location, and / or to further improve its wear comfort therein, the body of the device may be provided with an external coating or layer of a suitable coating material, especially one that provides a matt finish, e.g. a lacquer or varnish with appropriate desirable surface properties. Examples of suitable such coating materials may include various flexible polymer materials, elastomers or other natural or synthetic materials that provide appropriate or desirable surface properties to the exterior of the device body, specific examples of which are known and readily available in the art of intra-aural hearing aids, intra-aural earphones, and the like. One example of a commercially available suitable external coating layer material is that called “SoftTouch” [trade mark] from Dreve Otoplastik GmbH, which is an extremely elastic and light-curing lacquer which provides a good degree of wear comfort, anti-slip effect and soft haptics. Other commercially available examples of suitable coating materials may also be available. Such an external coating or layer material may be applied to the body in any suitable postproduction step after the formation of the device body itself, such as in a post-formation dipping procedure (e.g. dipping of the formed body into a liquid composition which forms a coating or layer of the desired coating material upon drying and / or curing) or a post-formation spraying procedure (e.g. spray-coating of the formed body with a composition which forms the desired coating or layer, especially upon its drying and / or curing). Other coating techniques may be possible. In view of the general requirement of embodiments of devices made using the invention that the body of the device should generally match or correspond to the internal shape of a section of the ear canal extending at least part of the way from proximal its entrance and to the vicinity of or adjacent to the second bend (when the jaw is in an open position), it is a feature of the practising of practical embodiments of the method of the invention that the method of making the main body of the device of the invention lends itself especially well to the use of 3D (three-dimensional) printing technology. For use in embodiments of the above production method of the invention involving 3D printing, it may typically be that the polymeric material that forms the body of the device may be formed by a process of in situ polymerisation of a photoactive or photoreactive monomer, optionally in combination with a polymerisation catalyst or promotor (or polymerisationpromoting conditions), if the chemistry of the system requires that. In practical embodiments of the above production method, any suitable known techniques and / or apparatuses may be used for effecting the aforementioned three-dimensional modelling and 3D printing steps. Some specific examples of such techniques and apparatuses will be described in further detail hereinbelow, in the context of some currently preferred embodiments of the invention and how they may be carried out in practice. Within the scope of this specification it is envisaged that the various aspects, embodiments, examples, features and alternatives, and in particular the individual constructional or operational features thereof, set out in the preceding paragraphs, in the claims and / or in the following description and accompanying drawings, may be taken independently or in any combination of any number of same. For example, individual features described in connection with one particular embodiment are applicable to all embodiments, unless expressly stated otherwise or such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the present invention in its various aspects will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: FIGURES 1(a), (b) &(c) are various schematic sectional views of a human temporomandibular joint (TMJ), illustrating some of the relative positions of the articular disc and associated retrodiscal tissues, ligaments, etc, some of which can amount to or lead to TMJDs which can cause pain or discomfort in the subject; FIGURE 2 is a sectional diagram illustrating the general arrangement and configuration of the principal features of a human ear canal; FIGURE 3 is a scanning image model of a human ear canal, showing its principal features along a major section of its length; FIGURE 4 is a moulded impression model of a human ear canal, showing the principal features along a major section of its length, and also illustrating the locations of certain key portions of an intra-aural device made according to various embodiments of the invention, once it has been inserted into the ear canal into its optimum placement location; FIGURE 5 is a schematic part-sectional representation of the ear canal of FIGS. 3 &4 with an intra-aural device made according to a first embodiment of the invention in situ therein in its optimum placement location; FIGURE 6 is a side-perspective view of the device of the first embodiment; FIGURE 7 is a front (proximal)-end-perspective view of the device of FIG. 6; FIGURE 8 is a distal-end-perspective view of the device of FIG. 6, viewed in perspective from its opposite, distal end (i.e. from that end opposite to that which the view of FIG. 7 is from); FIGURE 9 is similar to FIG. 7, being a front (proximal)-end-perspective view of the device of FIG. 6, but from a lower perspective angle, showing more clearly the manner of attachment of a removal-aiding cord or string by means of which the device can be removed from the ear as or when required; and FIGURES 10(a), (b) &(c) correspond generally to FIGS. 6, 7 and 9, but show an alternative embodiment of intra-aural device made according to the invention, which includes an optional hole / aperture feature for aiding extraction of the device from the ear canal if or when required. DETAILED DESCRIPTION OF EMBODIMENTS In general terms a device made according to some preferred embodiments of the invention - which “device” may alternatively be termed herein an “intra-aural device” - is designed and configured so as to conform to the internal shape of at least a major portion of a generally central or mid- or major section of the ear canal when the ear canal is in an expanded state, i.e. when the jaw is in an open position. That central / mid / major section of the ear canal may be defined generally as that section of the canal extending at least from proximal its entrance (i.e. adjacent the canal’s proximal end), past the isthmus, and to the vicinity of the second bend. The general arrangement and configuration of the principal features of this section of the ear canal, including its entrance, first bend, isthmus and second bend, are shown in FIG. 2. When in its intended position in the ear canal, such devices of embodiments of the invention resist compression of the ear canal but increase the compression of the retrodiscal tissues, which results in the anterior positioning of the retrodiscal tissues owing to biomechanical feedback. This encourages the jaw to return to a passive, slightly depressed position, thus reducing para-functional occlusal loads and associated myalgia, and reducing tension on the disc ligaments, which tensions can sometimes result in internal derangements of the articular disc, manifesting itself as just one example of a TMJD. Thus, such devices of embodiments of the invention may serve to reduce stresses on the ligaments of the articular disc and promote slight mandibular depression, which may also usefully result in a reduction in damaging para-functional habits. In this manner, intra-aural devices made according to such embodiments of the invention may act to provide a unique form and degree of support to the TMJ and associated anatomical structures, by supporting and / or altering the pressures placed on the TMJ, and in particular on the retrodiscal tissues, the anterior and posterior disc ligaments, the condylar head, the temporal bone, articular disc and capsule and associated nerves, and also by aiding the relief of stresses on the muscles of mastication and associated ligaments, nerves and vessels. The unique positioning site within the ear canal that such devices are designed and configured to be present at, and to be stably retained at - namely the location of the device’s proximal end at a site inwardly spaced from (i.e. spaced in a distal direction from) the ear canal’s entrance, and / or the location of the device’s distal end at a site in the region or vicinity of the 2nd bend - may serve to optimize this functionality. In particular, this / these unique location(s) of the device’s proximal and / or distal ends, and thus the overall distance by which the device extends into the ear canal, may lead to improved stability of the device in the ear canal, a minimizing of an occlusion effect on hearing, and it may resist occlusal effects and posterior displacement of the device which could otherwise reduce its efficacy. As a result, effective alleviation of TMJD symptoms such as pain or discomfort, and in some cases even muscular hypertrophy, originating therefrom may be achieved by use of intra-aural devices according to embodiments of the invention. Furthermore, this more efficient manner of tackling TMJD symptoms may offer relief from at least some of the significant financial burden and biological cost that known approaches to treating TMJDs symptoms involve. Indeed, compared with many prior art TMJD treatments that have traditionally involved the use of occlusal splints or more invasive and expensive techniques, intra-aural devices made in accordance with embodiments of the present invention offer a simple and easy way of treating such maladies without worries of creating mal-occlusions, hyper-salivation, difficult day-time wear and uncomfortable night-time wear, and without having to resort to more invasive techniques that may typically be accompanied by unnecessary lavage, arthrocentesis or even surgery. Referring firstly to FIGS. 1(a), (b) &(c), these show schematically a human temporomandibular joint (TMJ) and some of the relative positions of the articular disc and associated retrodiscal tissues, ligaments, etc which can amount to or lead to TMJDs which may lead to pain or discomfort in the subject. FIG. 1(a) shows the normal position of the articular disc of the TMJ and associated retrodiscal tissues. A common source of TMJD pain is internal disc derangement. When the mandible is depressed and the teeth are in an unoccluded position (i.e. at rest), the disc and retrodiscal tissues are also relaxed and at rest, juxtaposed between the condylar head and the temporal bone. If there is articular disc derangement, the disc translates into a dislocated position when the mandible is elevated. This can often result in pain and tenderness of the TMJ and is often associated with distressing “clicking” and / or “popping” noises from the joint as the condylar head moves from the articular eminence to the glenoid fossa - as illustrated in FIG. 1(b). This is due to the fact that when the disc is pathologically displaced anteriorly there is strain placed on the retrodiscal tissues, which can cause TMJ and ear pain. Such anterior strain can also affect other muscles of mastication and may have a role in myalgia. Furthermore, para-functional habits that cause this undue stress peak at maximal occlusion, with additional occlusal forces exacerbating the problem - as illustrated in FIG. 1(c). This can result in headache, neck ache, myospasm, arthralgia and myalgia in the head and neck. Underlying the present invention is a proposed mode of action for remedying or countering the effects of the aforementioned processes, which is through the intra-aural insertion of the device of the invention. This device may cause, upon mandibular elevation, the retrodiscal tissues and condylar head to be ventrally positioned, thus reducing the strain on the posterior ligament, the anterior ligament and minimising the excessive occlusal pressures from post maximal para-functional stresses on the joint. This same mechanism may reduce muscular tension in the muscles of mastication and thereby reduce consequential myalgia. Minimising disc derangement in this way may also minimise eburnation between the condylar head and the glenoid fossa, thus reducing pain from TMJD-related arthralgia. The intra-aural device made according to embodiments of the invention may therefore, once inserted into its intended position in the ear canal, keep the ear canal at its maximal width / diametrical / transverse dimension which occurs during mandibular depression. Being substantially rigid, the inserted device may prevent the natural decrease in ear canal dimensions which would ordinarily occur with mandibular elevation and caudal translation of the condylar head. The inserted device, being substantially rigid, may thus retain the increased ear canal dimensions and thus provide support for the condylar head, articular disc and retrodiscal tissues. The result of this is that the disc may be retained in the anatomically correct or optimal position juxtaposed between the condylar head and the temporal bone, thereby retaining its proper and uncompromised function and reducing pathology and pain or discomfort. Furthermore, embodiments of the invention may not be limited in their therapeutic application to the treatment of myalgia and internal derangement, but embodiments of the invention in its various aspects may address causalities from all aspects of TMJD aetiologies. Referring now to FIGS. 3 and 4, these drawings show a scanning image model (e.g. obtained by a CBCT (cone beam computed tomography) scanning technique) and a moulded impression model (e.g. a silicone impression) of a human ear canal, each showing the ear canal’s principal features along a major central section of its length, and in the case of FIG. 4 also showing the locations of certain key portions of the intra-aural device once it has been inserted into the ear canal into its optimum placement location. The ear canal shown generally as 4 extends generally from it entrance 4E, which is located adjacent or just distally inwardly from the outer auricle (or pinna) 2, inwardly in a distal direction towards the inner ear (not shown) where lie the eardrum and the other anatomical components of the hearing mechanism. Although the ear canal may be thought of generally as an elongated tubular structure, in reality it is of a somewhat convoluted asymmetrical configuration, as represented by its 3D modelled shapes shown in FIGS. 3 and 4. Its key features along its length, passing in a distal direction from its entrance 4E, include the first bend B1, the isthmus Is (namely, the narrowest point of the canal, marked by a bony-cartilaginous junction between the outer one-third and the inner two-thirds of the canal), and the second bend B2. As shown more clearly in FIG. 4, and further shown in general terms in FIG. 5, for its optimal length and placement location in the ear canal 4, the intra-aural device 10 of a first preferred embodiment of the invention has a distal (i.e. inner) end that extends to a location site 60 a distance D2 past or beyond (i.e. inwardly or distally of) the isthmus Is and into the region of the second bend B2. Moreover, rather than extending in the opposite (proximal or outer) direction fully up to the ear canal’s entrance 4E, the opposite proximal (i.e. outer) end of the device 10 terminates at a location site 50 just inwardly short of, i.e. a short distance D1 inwardly spaced from, in a distal direction, the ear canal’s entrance 4E. By way of example, for a typical human adult ear canal, the optimum position of the device 10’s distal end’s location site 60, at a distance D2 past or beyond (i.e. inwardly or distally of) the isthmus Is may be approximately 2-5 mm past or beyond the isthmus Is, and the optimum position of the device 10’s proximal end’s proximal location site 50, at a distance D1 from the ear canal’s entrance 4E may be approximately 2 - 5 mm. Of course, the exact distances D1, D2 may vary within these ranges according to a subject’s unique ear canal size, length and associated anatomical details in the region of the outer and inner ear. Referring now to FIGS. 6 to 9, these drawings show the intra-aural device 10 made according to the first preferred embodiment of the invention from various aspects, and illustrate its principal constructional and configurational features. FIG. 5 shows this device 10 in situ, having been inserted into the ear canal 4 from the outside so as to be located in its correct intended location therein (as described above), which is with its distal end (i.e. the distal end of its distal portion 24) located in that portion of the ear canal 4 at or adjacent the second bend B2 (and a distance D2 past the isthmus Is), and also with its proximal end located in that portion of the ear canal 4 just inwardly (i.e. distally) spaced (a distance D1) from the ear canal’s entrance 4E. The device 10 is formed as a substantially rigid, generally tubular, hollow body 14, whose exterior conforms to a high degree of accuracy to the internal shape and configuration of the section of the ear canal of the person or subject for whom the device 10 is intended for use, that defining internal shape and configuration of the ear canal being that when the jaw is in an open position, especially open at a set or predefined inter-incisal distance (which distance may of course depend on the patient or subject’s overall anatomical dimensions in the vicinity of their TMJ and ear canal). More specifically, in practising many embodiments, a general value appropriated to the level of mandibular depression for defining that internal shape and configuration of the ear canal may be that measured upon there being an inter-incisal separation distance of approximately 16-18 mm (that in particular being typical for an average human adult). However, this precise inter-incisal separation distance may be slightly larger or smaller than this depending on individual patients’ / subjects’ precise aural anatomies and sizes. As noted above, the device 10 comprises a substantially rigid, generally tubular, hollow body 14, e.g. formed of polyacrylate polymer, which comprises a distal (i.e. inwardly pointing) end portion 24 and a proximal (i.e. outwardly pointing) end portion 20. The latter (proximal) end portion 20 is formed with a lip or mouth portion 12, which tapers narrowingly moving from the lip’s proximal end boundary in a distal direction along the body (as seen more clearly in FIG. 8), so as to join the main body 14 of the device at a waist or neck portion 16. The body 14 has a hollow channel or bore 22 passing therethrough, for aiding the passage of sound waves through the device 10, so as not to unduly or significantly impair the person’s hearing while the device 10 is in situ in the ear canal 4. The tubular, hollow body 14 has sidewalls which are of a sufficient thickness to enable the device body 14 to substantially hold its substantially rigid shape once it has been inserted into position in the ear canal 4. Suitable such wall thicknesses are typically in the range of from about 1 to about 2 mm. Although in some embodiment forms the wall thickness of the tubular body 14 may be substantially uniform or constant along the length of the tubular body 14, moving along its tubular length, it may be more desirable in certain other embodiment forms for the wall thickness to vary along its length, for example ranging from about 1 mm at the proximal end 20 of the device body 14 and increasing in thickness to about 2 mm at the distal end 24 of the device body 14. This gradual thinning of the tubular structure’s walls moving from its distal to its proximal ends helps to improve the comfort of wear of the device 10 and also helps to reduce its occlusion effect in the ear canal 4. The device 10 may be constructed using 3D scanning of a silicone impression taken of the ear canal 4 (according to well-known techniques) or alternatively through direct scanning of the ear canal, such as using CBCT (cone beam computed tomography) scanning or like technologies. The consequent scan (as shown for example in FIG. 3) is then assessed for the optimal overall longitudinal length and respective end positionings of the device when located at its appropriate location within the ear canal. By way of example, one method of creating the device may involve the patient first biting on a bite block of predetermined size. An impression is then taken of the ear canal with an appropriate impression material such as polyvinyl silicate, or a scan is taken directly of the ear canal either by CBCT or other intra-aural scanning techniques. The impression or scan is then utilised to provide a 3D digital model of the internal anatomy of the ear canal during mandibular depression, as defined above. In an alternative first step of the method the patient may instead use the junction of the 1st knuckle of the thumb to establish the correct inter-incisal distance for the impression taking. The scan model, or the scan of the impression model (if that technique is employed) is then used as the basis for a 3D printing technique to build the structure of the body so as to form the device 10 according to the precise measurements and configuration as defined by the scan. Thus, the device so produced may in effect be an exact (or as close as possible exact) analogue of a section of the ear canal internal space in three dimensions upon mandibular depression. Suitable 3D printing apparatuses and methods are well-known in the art and nowadays widely commercially available, so will be well within the general knowledge of, and availability to, the skilled person. By way of example, the 3D printing of the body of the device 10 may be form a polyacrylate polymer, built up using a photo-active acrylate monomer. However, various other suitable photo-active or photosensitive monomers, or other monomers designed for use with other polymerisation techniques in 3D printing may also be used, as will be readily available in the art of constructing substantially rigid polymeric bodies. In order to facilitate the removal of the device 10 from the wearer’s ear canal as or when required, e.g. when its use or presence is not needed (e.g. overnight) or when it needs to be replaced, a cord, string or wire 36 (as shown in FIG. 9) may be provided, attached to the lip or mouth portion 12 of the device body, which may be manually grasped for the purpose of extracting the device 10 from the ear canal. Alternatively, a tab, pin, leg, arm, or other extension or protrusion extending from the lip or mouth portion 12 may be provided instead, especially one which is integrally formed with the lip / mouth portion 12. The cord, string or wire 36 (or alternatively tab, pin, leg, arm, or other extension or protrusion) may usefully be attached to the device body’s lip / mouth portion 12 at or via an enlarged attachment prominence or nose portion 26, which may typically be located midway along (and optionally slightly distally displaced from (e.g. spaced by up to about 1 or 2 or 3 mm from)) the edge of the lip / mouth portion 12 of the device body at its proximal end. Alternatively, the cord, string or wire 36 (or alternatively tab, pin, leg, arm, or other extension or protrusion) could be attached to the device body 14 at any other suitable location thereon, especially a location adjacent or in the vicinity of the bottom of the device body 14 when the device 10 is in position in the ear canal 4. In some alternative embodiment devices, still within the scope of the invention, various modifications or variations in certain specific features from those specifically described above and shown in the accompanying drawings may be employed, if desired or appropriate. For example: In order to further aid the device 10’s retention or stability in the ear canal once inserted therein into its desired location, and / or to further improve its wear comfort therein, the body of the device 10 may be provided with an external coating or layer of a suitable coating material, especially one that provides a matt, anti-slip finish, e.g. a flexible polymer material, elastomer or other natural or synthetic material that provides appropriate or desirable surface properties to the exterior of the device body. One example of a commercially available suitable external coating layer material is that called “SoftTouch” [trade mark] from Dreve Otoplastik GmbH, which is an extremely elastic and light-curing lacquer which provides a good degree of wear comfort, anti-slip effect and soft haptics. Such an external coating material may be applied to the device body by any suitable post-production technique, e.g. a dipping or spraying technique. Suitable examples of such coating materials may be already known and readily available in the art of intra-aural hearing aids, intra-aural earphones, and the like. As a further variation example, although the above-described embodiment device 10 is shown and described as being hollow in order to preserve sounds transmissions capabilities as far as possible, in an alternative embodiment device according to the invention the body of substantially rigid material that forms the device may be intentionally formed with a substantially solid or continuous internal structure (or possibly even a porous or closed- or open-cell internal structure) throughout its internal diameter or width. Such a body may thus be without any continuous longitudinal internal bore or channel formed therethrough. This feature of such an alternative embodiment may find use for intentional noise- or soundocclusion or cancellation purposes or hearing protection, e.g. in the case of a person in need thereof or where such an auxiliary purpose may be desirable or wanted. As a yet further variation example, in yet further alternative embodiments as variations of either the above-described and illustrated hollow version(s) of the device, or even the solid / continuous-internal-structure version described in the preceding paragraph, the relevant body may be formed or provided with a sound reproduction device, e.g. an earphone or miniature loudspeaker, mounted therein, in order to provide an earpiece- or “earbud”-type device for the listening to of music, spoken words or other audio content or for telecommunications purposes (e.g. in combination with a mobile phone or other mobile device). In yet another alternative embodiment device 10’, as illustrated in FIGS. 10(a), (b) &(c), which may correspond in most of its structural and configurational features to the other embodiment devices 10 described above and shown in FIGS. 6 to 9, as an alternative to - or even as an additional feature to - the above-mentioned manually graspable cord, string or wire 36 (or alternatively tab, pin, leg, arm, or other extension or protrusion), the device 10’ may be provided with an auxiliary removal / extraction-aiding feature, in the form of a small through-hole or aperture 70 formed in a sidewall of the device’s body 14. The through-hole or aperture 70 can be used to engage a manual tool, such a wax hook, for manually removing or extracting the device 10’ from the ear canal 4 if / as or when required. Such a through-hole or aperture 70 can typically be in the form of a small circular or elliptical (or other suitably shaped) hole / aperture of around 2 mm across / in diameter, located adjacent - especially a short distance (e.g. around 2 mm) in from - the peripheral edge of the device body 14’s proximal end 20. Furthermore, the location of the through-hole or aperture 70 can usefully be on that side of the device body 14 which is closest to, or in the vicinity of or adjacent, the tragus of the outer ear when the device 10’ is in position in the ear canal 4. This auxiliary removal / extraction-aiding through-hole / aperture feature 70 can be particularly useful for removing / extracting the device 10’ from the ear canal 4 (e.g. by use of a wax hook, such as might be practised by any professional that carries out wax removal procedures, such as an ear care nurse or audiologist) particularly in those embodiments where a manually graspable cord, string or wire 36 is also provided as a primary removal aid but it has become damaged or detached from the device 10. Alternatively, the auxiliary removal / extraction-aiding through-hole / aperture feature 70 could even be provided as an entire alternative to the cord, string or wire-based primary removal aid feature altogether. Throughout the description and claims of this specification, the words “comprise” and “contain” and linguistic variations of those words, for example “comprising” and “comprises”, mean “including but not limited to”, and are not intended to (and do not) exclude other moieties, additives, components, elements, integers or steps. 5 Throughout the description and claims of this specification, the singular encompasses the plural unless expressly stated otherwise or the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless expressly stated otherwise or the context requires otherwise. 10 Throughout the description and claims of this specification, features, components, elements, integers, characteristics, properties, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein 15 unless incompatible therewith or expressly stated otherwise. LD CM

Claims

1. A method for making a device for insertion into an ear canal of a human subject to alleviate symptoms of temporomandibular joint (TMJ) disorders thereof, the subject’s ear canal including an entrance, a first bend, an isthmus and a second bend, wherein the method comprises:(i) making, by means of (a) making a 3D scanning image, or (b) making a 3D moulded impression, or (c) a combination of (b) and (a), a three-dimensional model of the internal shape of at least a section of the subject’s ear canal extending from (A) a site within the subject’s ear canal which lies distally spaced from (i.e. spaced in a distal direction from, and measured in the longitudinal direction of the ear canal) the subject’s ear canal’s entrance by a distance of from 1 up to 7 mm, and to (B) a site within the subject’s ear canal which is within a distance (measured in the longitudinal direction of the ear canal) of up to 4 mm proximally short of the second bend or up to 4 mm distally beyond the second bend, when the subject’s jaw is in an open position; and(ii) producing an elongate body of substantially rigid material exteriorly shaped and configured to substantially match the exterior shape of the three-dimensional model of the said section of the subject’s ear canal made in step (i), to form the said device for insertion into the said section of the subject’s ear canal;wherein the production step (ii) is carried out using a 3D printing technique.

2. A method according to claim 1, wherein, in the step (i) of making the three-dimensional model of the internal shape of at least the section of the subject’s ear canal, the said section extends from (A) a site within the subject’s ear canal which lies distally spaced from (i.e. spaced in a distal direction from, and measured in the longitudinal direction of the ear canal) the subject’s ear canal’s entrance by a distance of from 2 up to 5 mm, when the subject’s jaw is in an open position.

3. A method according to claim 1 or claim 2, wherein, in the step (i) of making the three-dimensional model of the internal shape of at least the section of the subject’s ear canal, the said section extends to (B) a site within the subject’s ear canal which is within a distance (measured in the longitudinal direction of the ear canal) of up to 2 mm proximally short of the second bend or up to 2 mm distally beyond the second bend, when the subject’s jaw is in an open position.

4. A method according to claim 3, wherein, in the step (i) of making the three-dimensional model of the internal shape of at least the section of the subject’s ear canal, thesaid section extends to (B) a site within the subject’s ear canal which is substantially at the second bend thereof, when the subject’s jaw is in an open position.

5. A method according to any preceding claim, wherein, in the step (i) of making the three-dimensional model of the internal shape of at least the section of the subject’s ear canal, the said section extends to (B) a site within the subject’s ear canal which lies distally beyond (i.e. beyond in a distal direction, and measured in the longitudinal direction of the ear canal) the isthmus of the ear canal by a distance of at least 2 mm, when the subject’s jaw is in an open position.

6. A method according to claim 5, wherein, in the step (i) of making the three-dimensional model of the internal shape of at least the section of the subject’s ear canal, the said section extends to (B) a site within the subject’s ear canal which lies distally beyond (i.e. beyond in a distal direction, and measured in the longitudinal direction of the ear canal) the isthmus of the ear canal by a distance of at least 4 mm, when the subject’s jaw is in an open position.

7. A method according to any preceding claim, wherein, in the step (ii), the elongate body of the device that is produced is a generally elongated body with at least one longitudinal internal bore or channel formed through the body, whereby the body is tubular and substantially hollow throughout its longitudinal length.

8. A method according to claim 7, wherein, in the step (ii), the elongate body of the device that is produced is an elongate tubular body which is formed with sidewalls with a thickness that enables the device body to substantially hold its substantially rigid shape.

9. A method according to claim 7 or claim 8, wherein, in the step (ii), the elongate body of the device that is produced is an elongate tubular body whose sidewall thickness is substantially uniform or constant along the length of the device, moving along its tubular length.

10. A method according to claim 7 or claim 8, wherein, in the step (ii), the elongate body of the device that is produced is an elongate tubular body whose sidewall thickness varies along the length thereof, the sidewall thickness gradually decreasing moving from the tubular body’s distal to its proximal ends.

11. A method according to any preceding claim, wherein, in the step (ii), the elongatebody of the device is formed of a polymeric or plastics material, or specifically of a polyacrylate polymer.

12. A method according to claim 11, wherein, in the step (ii), the polymeric material that forms the body of the device is formed by a process of in situ polymerisation of a photoactive or photoreactive monomer.

13. A method according to any one of claims 1 to 6, wherein, in the step (ii), the elongate body of the device that is produced is a generally elongated body formed with a substantially solid or continuous internal structure throughout its internal diameter or width, or with a porous or closed- or open-cell internal structure throughout its internal diameter or width.

14. A method according to any preceding claim, wherein, in the step (ii), the elongate body of the device is formed or provided with a sound reproduction device mounted therein, or specifically with an earphone or loudspeaker mounted therein.

15. A method according to any preceding claim, wherein, in the step (ii), the elongate body of the device that is produced comprises at least one portion which is shaped so as to include a narrowing tapering in the body’s external diameter or width passing longitudinally along that portion of the body in the distal direction.

16. A method according to claim 15, wherein, in the step (ii), the said tapering portion of the produced elongate body of the device is a proximal portion of the device body in the vicinity of a proximal end thereof, which proximal portion commences at or within a distance of 4 mm from the proximal end of the device body.

17. A method according to any preceding claim, wherein, in the step (ii), the elongate body of the device that is produced includes manually graspable means for aiding its removal from the subject’s ear canal when it is desired to remove it for any reason or to replace it.

18. A method according to claim 17, wherein, in the step (ii), the said removal-aiding means comprises either (a) a tab, pin, leg, arm, or other extension or protrusion extending from a portion of the body of the device at or adjacent its proximal end, or (b) a cord, string, wire or other elongate member attached to a portion of the body of the device at or adjacent its proximal end.

19. A method according to claim 18, wherein, in the step (ii), the said (a) tab, pin, leg,11 06 25arm, or other extension or protrusion, or (b) cord, string, wire or other elongate member extends from, or is attached to, the body of the device at a location midway along, or midway along and distally spaced by up to 3 mm from, a proximal edge or lip or mouth of the device body at its proximal end.

520. A method according to any preceding claim, wherein, in the step (ii), the elongate body of the device that is produced includes auxiliary removal-aiding means, for aiding the device’s removal from the subject’s ear canal when it is desired to remove it for any reason or to replace it, wherein the auxiliary removal-aiding means comprises a through-hole or 10 aperture formed in a wall or sidewall of the device, the through hole-aperture being for use with a tool to manually remove or extract the device from the subject’s ear canal if / as or when required.

21. A method according to claim 20, wherein, in the step (ii), the auxiliary removal-aiding 15 through-hole or aperture is located adjacent the proximal end of the device body, or adjacent the proximal end of the device body and on that side of the device body which is closest to, or adjacent, the tragus of the outer ear when the device is in position in the subject’s ear canal.20 22. A method according to any preceding claim, wherein, in the step (ii), the elongatebody of the device that is produced is provided with an external coating or layer of a coating material, or specifically with a coating material that provides a matt finish.

Images