WO2018117963A1

WO2018117963A1 - Cervical traction device

Info

Publication number: WO2018117963A1
Application number: PCT/SG2017/050628
Authority: WO
Inventors: Siaw Meng Chou
Original assignee: Nanyang Technological University
Priority date: 2016-12-20
Filing date: 2017-12-20
Publication date: 2018-06-28
Also published as: CN110114042A; CN110114042B

Abstract

A cervical traction device is configured to provide gravity-assisted cervical traction which relies on the natural bodyweight of the user. The device comprises areas of jaw contact on a superior side and areas of shoulder contact on an inferior side when the user lies supine on the device, wherein the two areas define therebetween a minimum predetermined spacing between the user's lower jaw and the user's shoulders; and a slot extending through the spacer downwardly with reference to the horizon when the cervical traction device is positioned to allow the user to lie supine on the cervical traction device, the slot allowing passage of the user's neck through the spacer, a bottom surface of the slot comprising an inferior surface having a downward slope in the inferior direction to allow shoulders of the user to slide downwardly and interiorly thereon to exert a traction force on the user's neck.

Description

CERVICAL TRACTION DEVICE

FIELD OF THE INVENTION

This invention relates to a cervical traction device.

BACKGROUND OF THE INVENTION

Cervical spondylosis is one of the most common degenerative conditions of the cervical spine mainly caused by age-related changes in the bones, intervertebral discs and joints. Hospital/clinic physiotherapy sessions present time and financial burdens for many patients. However, home-based methods and devices like over-the-door traction is difficult to set up and is non-compliant, or may comprise moving parts and expensive mechanical or electrical components that lack patient control and could thus potentially cause abnormal loading of the spinal segments, thereby worsening symptoms. Users may also not adhere to prescribed instructions thereby leading to unintended outcomes. There is thus a need to develop an economical home-based cervical traction device which is safe for the general population and especially the elderly.

SUMMARY OF INVENTION

The presently disclosed cervical traction device provides indirect gravity-assisted cervical traction which relies on the natural bodyweight of the user. It is customizable to fit the user and to provide safe and conservative treatment specific to the needs of the user.

According to a first aspect, there is provided a cervical traction device comprising:

a spacer having a superior side sloping upwardly in an inferior direction and an inferior side sloping downwardly in the inferior direction with reference to a user lying supine on the cervical traction device,

areas of jaw contact provided on the superior side to contact a lower jaw of the user and areas of shoulder contact provided on the inferior side to contact shoulders of the user when the user lies supine on the cervical traction device, wherein the areas of jaw contact and the areas of shoulder contact define therebetween a minimum predetermined spacing between the user's lower jaw and the user's shoulders; and

a slot extending through the spacer downwardly with reference to the horizon when the cervical traction device is positioned to allow the user to lie supine on the cervical traction device, the slot allowing passage of the user's neck through the spacer, a bottom surface of the slot comprising an inferior surface having a downward slope in the inferior direction to allow shoulders of the user to slide downwardly and inferiorly thereon to exert a traction force on the user's neck.

The areas of jaw contact may be contoured according to the lower jaw of the user.

The areas of shoulder contact may be contoured according to the shoulders of the user.

The bottom surface of the slot may further comprise a superior surface adjoining the inferior surface superiorly, the superior surface having an upward slope in the inferior direction to support a back of the user's neck thereon.

The cervical traction device may further comprise a head rest adjoining the spacer superiorly, the head rest configured to receive a back of the user's head thereon.

The predetermined spacing may be adjustable by selectably attaching a collar to at least one of: the superior side and the inferior side of the spacer. The areas of jaw contact may be provided on the collar attached to the superior side of the spacer.

The cervical traction device may comprise a 3D printed monolithic structure. Alternatively, the spacer may comprise a first piece and a second piece, wherein the first piece comprises the superior side, and wherein the second piece comprises the inferior side and the inferior surface.

BRIEF DESCRIPTION OF FIGURES

In order that the invention may be fully understood and readily put into practical effect there shall now be described by way of non-limitative example only exemplary embodiments of the present invention, the description being with reference to the accompanying illustrative drawings.

FIG. 1 is a schematic illustration of a superior perspective view of an exemplary embodiment of a cervical traction device.

FIG. 2 is a schematic illustration of a side view of the cervical traction device of FIG. 1. FIG. 3 is a schematic illustration of an inferior view of the cervical traction device of FIG. 1. FIG. 4 is a schematic illustration of superior perspective views, side views and inferior

perspective views of the cervical traction device of FIG. 1 shown with and without a user.

FIG. 5 is a schematic illustration of a side view of an alternative exemplary embodiment of a cervical traction device including a head rest.

FIG. 6 is a schematic illustration of a side view of an alternative exemplary embodiment of a cervical traction device comprising a spacer of two pieces.

FIG. 7 is a curve of typical creep curve of an intervertebral disc.

DETAILED DESCRIPTION

Exemplary embodiments of a cervical traction device 100 will be described below with reference to FIGS. 1 to 7 in which the same reference numerals are used to denote the same or similar parts.

As shown in FIGS. 1 to 4, in general, the cervical traction device 100 comprises a spacer 20. The spacer 20 is generally in the form of a wedge having two sides 28, 29: a superior side 28 comprising a superior gradient 21 upwardly and inferiorly to a top 23 of the spacer 20, and an inferior side 29 comprising an inferior gradient 22 sloping downwardly and inferiorly from the top 23 of the spacer 20. Common human anatomical directional terms such as "superior" (towards the head), "inferior" (towards the feet), "anterior" (projecting perpendicularly from the chest), "posterior" (projecting perpendicularly from the back) and so on that are used throughout the specification take reference from a human person using the cervical traction device 100 in a supine position, i.e., lying horizontally on the back. General directional terms such as "top", "bottom", "upward," "downward" take reference from the horizon when the cervical traction device 100 is placed in a normal position of use (as shown in FIG. 4).

The spacer 20 has a generally centrally provided slot 30 extending downwardly through the top 23 of the spacer 20 to allow passage of the user's neck 93 through the slot 30, thereby giving rise to two projections 33 that each extend upwardly on each side of the slot 30. The slot 30 extends downwardly to terminate in a superior surface 31 adjoining an inferior surface 32. The superior surface 31 and the inferior surface 32 together define a bottom surface of the slot 30. The superior surface 31 is preferably contoured with a relatively gentle upward slope in the inferior direction (when compared to the inferior surface 32) to support the back of the user's neck 93. The inferior surface 32 is preferably contoured with a relatively steep downward slope in the inferior direction (when compared to the superior surface 31) to allow shoulders 94 of the user to slide downwardly and inferiorly when the user lies down on the spacer 20, thereby creating a traction force on the user's neck 93.

The superior gradient 21 extends up the two projections 33 and is preferably contoured or designed with a customised profile to fit a lower part of the user's head (i.e., the chin and jaw area, otherwise referred to as the lower jaw 92) so that the superior side 28 of the spacer 20 on the two projections 33 fits comfortably to the profile of the user's lower jaw 92. An area of jaw contact 26 is preferably provided on the projections 33 on each side of the slot 30 on the superior side 28 of the spacer 20 so that forces exerted on the lower jaw 92 by the superior gradient 21 are well spread out over the lower jaw 92 area of the user and not at a localised point, so as to provide maximum comfort to the user.

The inferior gradient 22 is preferably contoured or designed with a customised profile according to the shoulders 94 of the user so that the inferior side 29 of the spacer 20 fits comfortably on the user's shoulders 94. An area of shoulder contact 27 is preferably provided on each side of the slot 30 on the inferior side 29 of the spacer 20 so that forces exerted on the shoulders 94 by the inferior gradient 22 are well spread out over the shoulders 94 of the user and not at a localised point, so as to provide maximum comfort to the user.

In an alternative embodiment, the cervical traction device 100 may further comprise a head rest 10 adjoining the spacer 20 superiorly, as shown in Fig. 5. The head rest 10 provided to receive and support the back of the user's head 91 thereon when the user lies supine on the cervical traction device 100, and is preferably shaped in a profile that conforms to the shape of the user's head 91. Where the device 100 also comprises the head rest 10, the head rest 10 and spacer 20 are preferably integrally formed and provided as a monolithic structure. The head rest 10 together with the superior side 28 of the spacer 20 provide a rigid support for the user's head 91. When the cervical traction device 100 is in use, the head 91 should preferably be well supported to minimise any movement of the head 91 in the axial direction in line with the spine of the user. In an exemplary embodiment of forming the cervical traction device 100, customized profiles of the head 91, neck 93 and shoulders 94 of the user may be obtained by appropriate 3D surface scanning of the user to obtain a 3D scan of the user. From the 3D scan of the user, a digital model of the cervical traction device 100 is created using available software, wherein profiles of the spacer 20 (and the head rest 10, if provided) and of the digital model of the cervical traction device 100 are customized by contouring according to the 3D scan of the user. The digital model is used to control an additive manufacturing apparatus to perform an additive manufacturing process to produce the spacer 20 (and the head rest 10, if provided) as specified by the digital model, thereby producing the cervical traction device 100. The additive manufacturing apparatus and process may comprise a 3D printer and 3D printing using an appropriate material, such as a thermoplastic. 3D printing ensures a good fit of the device 100 and accurate replication of the profile needed for maximum comfort and effectiveness as the manufacturing of the complex profile using conventional methods would be tedious, laborious and time-consuming. In addition, ensuring proper fit, which is essential for accurate traction, would be difficult manually.

The cervical traction device 100 thus comprises a structure comprising the spacer 20 having the upward sloping superior side 28 to contact the lower jaw 92 of the user to restrict axial movement of the head 91 and the downward sloping shoulder contours provided by the inferior side 29 and the inferior surface 32 at the bottom of the slot 30 to cause the shoulders 94 of the user to slide downwardly and inferiorly in order to provide traction to the neck 93 when the user lies on the cervical traction device 100. The structure or spacer 20, if 3D printed, can thus be said to be "moulded" to the user as it would be produced from a digital model of the cervical traction device 100 that is created from a 3D scan of the user. The "moulded" support provided by the cervical traction device 100 prevents the head 91 from moving together with the torso 95 of the user when cervical traction takes place.

The spacer 20 provides a corresponding wedge support via the inferior gradient 22 that provides a shoulder supporting area of shoulder contact 27 against the user's shoulders 94. The wedge support provided by the spacer 20 is customized to the user by appropriate profiling of the superior gradient 21, the inferior gradient 22 as well as the inferior surface 32 of the spacer 20, thereby exerting an axial cervical traction force when the user lies horizontally on the cervical traction device 100, as a result of a specially configured and predetermined spacing d provided by the spacer 20 between the lower jaw 92 and the shoulders 94 of the user, as shown in FIGS. 4 to 6.

In use, the cervical traction device 100 is preferably laid on a firm and flat mattress 200 as shown in FIGS. 5 and 6. When the user lies supine on the cervical traction device 100, the spacer 20, which has been specially configured and customized to suit the particular user, exerts an axial traction force on the neck 93 of the user due to the spacing d provided by the wedge-shaped spacer 20 between the user's lower jaw 92 and shoulders 94. This spacing <i is predetermined and customised according to a doctor's prescription or within a recommended range. The cervical traction device 100 therefore does not require any user control to work as traction is applied simply by the user lying supine on the cervical traction device 100. The amount of traction is also predetermined according to the customized spacing d, thereby providing a safe and comfortable prescribed traction amount with minimal risk of injury.

Using the body weight in a supine position together with the profile of the device 100 that is customized to the user, gravity-assisted traction can facilitate localized traction of the cervical spine. The technology used is based on basic solid mechanics and the deformation behaviour of materials. During sleep or in the supine position, the spine is at its minimal load as shown in FIG. 7. Non-recovered deformation may occur after instantaneous recovery and creep recovery especially for degenerated disc. The present cervical traction device 100 provides gravity-assisted traction produced by gravitational force (as indicated by the vertically downward arrows in FIG. 5) on the body in the supine position to generate the tractive force. The vertically downward gravitational force acting on the shoulders 94 resolves as a normal force perpendicular to the inferior surface 32 as well as a tangential force parallel to the downward slope of the inferior surface 32. The tangential force serves as the tractive force on the neck 93 between the head 91 and the shoulders 93 since the head 91 is held in place by the areas of jaw contact 26.

As time progresses, due to gravity, the weight of the body will further increase the wedge or spacing d between the head 91 and the shoulders 94 as the shoulders 94 slide further downwardly and inferiorly on the inferior surface 32 while the head 91 is held in place by the areas of jaw contact 26, thereby causing an increased traction force on the neck 93 or cervical spine. The profile of the device 100 is designed such that the traction force actuated will be relatively low and gradual, thus providing a relatively slow and passive force action for a relatively safe cervical traction.

As traction force increases, intervertebral disc (IVD) height will also gradually increase, proportional to the total displacement due to the wedge angle, thereby encouraging uptake of nutrients by and rehydrating of the intervertebral discs further. Impairment in the nutrient supply to the intervertebral disc is evident in disc degeneration. It can be shown that mechanical loading-induced convection could offer therapeutic benefit for degenerated discs by enhancing uptake of nutrients and clearance of by-products. Thus, frequent use of the device 100 may therefore slow down the rate of disc degeneration due to ageing, which is a cause of cervical spondylosis.

While the spacer has been described above as being preferably of a monolithic structure, the spacer 20 may alternatively be provided as at least two pieces 40, 50 that fit together in use, as shown in FIG. 6. A first piece 40 of the spacer 20 may comprise the superior side 28 having the areas of jaw contact 26 to contact the lower jaw 92 of the user, and a second piece 50 of the spacer 20 may comprise the inferior side 29 having the areas of shoulder contact 27 to contact the shoulders of the user as well as the inferior surface 32 at the bottom of the slot to allow the downward and inferior sliding of the shoulders to exert the traction force on the user's neck.

It should be noted that the spacing d may be changed by using a customised collar (not shown) that can be attached to the spacer 20. The customised collar may comprise one or more pieces of cushions or padding, or may be digitally printed to conform to the lower jaw 92 of the user. Where a collar is used, it will be understood that the areas of jaw contact 26 on the superior side 28 of the spacer contacting the lower jaw 92 of the user are now provided on the collar and not directly on the projections 33 of the spacer 20. The collar may be made interchangeable so that the same user can use the same base structure or spacer 20 of the cervical traction device 100 but with changeable support cushions or collar to achieve different dimensions of the spacing d for different traction outcomes. For example, adding a cushion or collar would increase the spacing d compared to the spacing d defined by the spacer 20 alone. In further alternative embodiments, the collar may instead be attached to one or both of the superior and inferior sides 28, 29 of the spacer 20. The cervical traction device 100 can also be built to accommodate different users by customising only specific portions of the cervical traction device 100. Important portions are the lower jaw support provided by the areas of jaw contact 26 on the superior side 28 and the spacer distance d which determines the amount of traction force exerted on the user.

The presently disclosed cervical traction device 100 is envisaged to be used for in-clinic or home-based cervical traction to alleviate symptoms associated with cervical spondylosis. Passive cervical traction provided by the cervical traction device 100 during rest in the supine position can be used to alleviate symptoms associated with cervical spondylosis. The cervical traction device 100 uses the inclined profile of the head 91 and torso 95 on the spacer 20 to allow gradual displacement of the torso 95 away from the head 91. This will promote conservative cervical traction which in turn encourages intervertebral disc unloading during sleep/supine position.

The cervical traction device 100 does not involve the application of external loads on the spinal segments, thereby providing safe and gradual cervical traction especially suitable for the elderly population. Through customization and 3D printing, device fit and comfort of patients can be enhanced. The proposed passive cervical traction device 100 is thus safe, user-friendly, economically viable, simple to use and portable (devoid of moving parts or complex electrical/mechanical components), making it appropriate for use by all patients including the elderly.

Whilst there has been described in the foregoing description exemplary embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations in details of design, construction and/or operation may be made without departing from the present invention. For example, the bottom surface of the slot 30 may be provided as a series of removable pieces that can be placed on the spacer 20, each piece having different slope angles of the superior surface 31 and inferior surface 32 in order to provide a series of stretching therapy to the user without having to replace the entire spacer 20.

Claims

1. A cervical traction device comprising:

2. The cervical traction device of claim 1, wherein the areas of jaw contact are contoured according to the lower jaw of the user.

3. The cervical traction device of any one of the preceding claims, wherein the areas of shoulder contact are contoured according to the shoulders of the user.

4. The cervical traction device of any one of the preceding claims, wherein the bottom surface of the slot further comprises a superior surface adjoining the inferior surface superiorly, the superior surface having an upward slope in the inferior direction to support a back of the user's neck thereon.

5. The cervical traction device of any one of the preceding claims, further comprising a head rest adjoining the spacer superiorly, the head rest configured to receive a back of the user's head thereon. The cervical traction device of any one of the preceding claims, wherein the predetermined spacing is adjustable by selectably attaching a collar to at least one of: the superior side and the inferior side of the spacer.

The cervical traction device of claim 6, wherein the areas of jaw contact are provided on the collar attached to the superior side of the spacer.

The cervical traction device of any one of the preceding claims, wherein the cervical traction device comprises a 3D printed monolithic structure.

The cervical traction device of any one of claims 1 to 7, wherein the spacer comprises a first piece and a second piece, wherein the first piece comprises the superior side, and wherein the second piece comprises the inferior side and the inferior surface.