GB2205039A

GB2205039A - Device to monitor spinal flexion

Info

Publication number: GB2205039A
Application number: GB8712516A
Authority: GB
Inventors: Simon Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-05-28
Filing date: 1987-05-28
Publication date: 1988-11-30
Also published as: GB8712516D0

Abstract

A device for monitoring spinal flexion in the human body has a reference means (10) in the form of a casing, which, in use, is positioned in the lower back region, preferably in the region of the twelfth dorsal D12 vertebra. An elongate monitoring member (12) extends from the casing, and in use its end contacts the first sacral S1 vertebra of the back. An electrical signaling circuit with an audible warning is housed within the housing (10), and is actuated when an electrical contact (28) on the elongate member (12) engages a corresponding contact (42) within the housing, which occurs when flexion of the spine exceeds a predetermined amount. <IMAGE>

Description

DESCRIPTION OA DEVICE TO MONITOR SPINAL FLEXION".

The present invention relates to the field of biomechanics, and in particular, to a device for monitoring the degree of flexion of the spine.

.Back ache is a very common medical condition.

Sometimes in their lives 80% of people are likely to be temporarily disabled by lower back trouble and 60% of people will suffer from chronic back pain (Anderson JAD 1980).

As well as the physical suffering caused#to patients, back pain is the medical condition which gives rise to the greatest economic cost to Industry in terms of time off work of any comparable group of complaints (Cochrane report, working party on back pain 1979).

The extent of this problem can be seen in that there are over one million new cases of lower back pain referred to doctors in the U.K. each year alone. and of these, half a million lead referrals to a specialist clinic (Benn and Wood 1975). The major problem in treating such pain is that the anatomical source of the pain is usually unknown (Kellgren 1977). Thus, most treatment at present takes the form of preventing recurrence by teaching preventative medicine, in which physical fitness, weight control and the avoidance of bending and heavy lifting with the spine flexed is taught (O'Brien .P. 1980).

At present patients are educated by counselling or by the use of video recordings which emphasise the importance of postural control. However, it is obvious from the large number of patients who repeatedly return to the clinic that the present methods of educating patients have proved unsatisfactory. Furthermore, many patients feel that they are not receiving satisfactory treatment.

The present invention has for its object the provision of a device which will assist the patient to carry the counselling into effect by indicating to the patients when they are making those movements which flex the spine in a manner likely to cause damage. By making them continually aware of those movements which cause damage, they can learn to avoid making such movements.

In accordance with the present invention, there is provided a device for monitoring spinal flexion in the human body comprising reference means disposable in abutting relationship with the lower back of a human body, monitoring means movable relative to the reference means in response to flexion of the spine of said human body and signal means actuated when a predetermined degree of movement of the monitoring means occurs relative to the reference means.

The degree of spinal flexion determines the amount of movement of the monitoring means relative to the reference means and when a predetermined degree of flexion of the spine occurs, the signal means is actuated and emits a warning signal to the wearer. The device is generally preset so that å warning signal is emitted when physiological lordosis of the lumbar spine is lost.

This approximates to the degree of spinal flexion necessary to touch the knees with the hands when the legs are locked at the knees.

In one embodiment the signal means may conveniently be housed in the reference means, and may take the forn of a battery operated signal device which emits a characteristic sound on being actuated by an electric current from the battery, the monitoring device actuating a switch which applies the electric current to the signal device when sufficient flexion of the spine occurs. Thus the monitoring means may be adapted to nold the switch in the off position until flexion of the spine exceeds the permitted limits when the switch is allowed to close and thus actuate the signal device to emit the warning signal.

The monitoring portion may for example be in the form of an elongate resiliently deformable rod which is movably attached to the reference portion by a connecting means such as a hinge, the rod being positioned such that it is bent when in contact with the back of the person with the spine in the unflexed position, the rod having switc'n-actuating means associated therewith adapted to keep the switch in the open position whilst the spine is. within permitted degrees of flexion, but to close the switch when the permitted degree of flexion of the spine is exceeded. The switch actuating device is preferably adjustable to allow the degree of flexion required to trigger a warning signal to be adjusted to the needs of each patient.

The signal means may be audible and/or visual and may be further adapted to increase the signal intensity with time after physiological lordosis of the spine is lost. The signal means may also include a delay means which allows flexion beyond the permitted limits for a brief period before the signal means is actuated.

It may also contain a timing device to measure the overall time of use and the total time the device is in tne signalling position. The apparatus may have suitable attachments to allow it to be worn via a belt and is preferably shaped so as to fit snugly against the small of the back (thereby) spanning the twelfh dorsal D12 and first sacral S1 vertebrae. Since most back problems are at the L4/5 or L5/S1 joints. Thus when the monitoring means is a resiliently deformable rod it is generally 13 cms long for an average sized adult.

In another embodiment the reference means and one or more monitoring means may be independently attached to the back of the person, signal actuating means being associated with each monitoring#means.

In yet another embodiment the monitoring means and the reference means may both be housed in a flexible container, the signal actuating means comprising for example, a light beam passing between the reference means and monitoring means in conjunction, with a light-actuated switch or switches so disposed as to be actuated by the light beam on sufficient relative movement of the reference and monitoring means caused by flexing of the flexible container responsive to flexion of the spine.

By way of example only, a specific embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a detailed perspective view of the device; Fig. 2 is a view of the device with the cover removed showing the elctrical circuitry; Fig. 3 is a cross section of line III-III of Fig. 2. The dotted line indicating the position of the tongue when the device correctly abuts the spine; Fig. 4 is a perspective view of a device according to this invention as worn on a belt.

Referring to Figs. 1 to 3, a flexion monitoring device 10 comprises an elongate resiliently deformable tongue 12 which passes into a two part housing 14, comprising a base 16 and a cover 18, through a rectangular aperture 20 formed by adjacent cut out sections of the base 16 and the''cover 18. Two further pairs of adjacent cut out sections of base 16 and cover 18 form apertures for a volume knob 22 and an on/off knob 24. A circular aperture 26 provided in cover 18 provides access to an adjustable electrical screw contact 28. A series of parallel slots 30 in cover 18-allows sound to be emitted from a buzzer 32 disposed inside the housing. Cover 18 also has a rectangular aperture 34 which receives a battery cover plate 36.Batteries 38 are disposed in the base 16 immediately behind plate 36 and so can be removed and replaced without having to remove the whole of the cover 18 of the device 10.

The electrical circuitry generally designated by 40 comprises a d.c. battery 38, an on/off switch 24, a volume control 22 and a buzzer 32 which are linked together to form an electrical circuit which is completed by a further switch made by the contacting of two electrical contacts 28 and 42. The electrical contact 28 is in the form of an adjustable screw and is rigidly and movably attached to and in electrical contact with the metal 44 of the tongue 12 and moves with said tongue.

A metal boss 46 is affixed to the metal 44 of the tongue and provides a thickened area which has a threaded bore 48 passing through it which is correspondingly threaded to allow the electrical screw contact 28 to be adjusted therein. Positioned opposite the screw contact and fixedly attached to the base of the housing is the other electrical contact 42. The tongue is fixed at its base by two screws 50 and 52. Between the screws 50, 52 and the contact 28 and width of the tongue reduces to form a neck 54. The metal tongue is also partly coated with plastics such that the area of tongue 56 externally positioned with respect to the housing is coated.

Fig. 4 shows the flexion monitoring device 10 held in a pouch 58 formed on a belt 60. When the belt is fitted around the waist of a patient the device is positioned so as to allow the tongue 12 of the device to abut the patients lower back, preferably such that the tongue lies alongside the spine, such that it spans the first sacral to twelfth dorsal vertebrae.

Considering the device from a functional view point, the device is worn such that the base 16 is in abutment with the lower back. Thus the device 10 is preferably worn inside a pouch 12 formed in a belt 14. The belt being fitted around the waist of the patient thereby holding the device in close abutment to the lower back.

The tip of the tongue remote from the housing thus abuts the spine in the upper area of the small of the back, preferably around the twelfth dorsal vertebrae. Thus the tongue takes up the position indicated by the dot-dash line of Fig. 3 when the back is in physiological lordosis.

In this position the contacts 28 and t2 are separated from one another and the electrical circuit is incompleted.

Thus no sound is emitted-by the buzzer.

The tongue 12 to which the screw contact 28 is fixedly attached is biassed towards the contact 42 by means as will be described hereunder. When no force is exerted against the tongue in a direction from the base 16 to the cover 14 the contacts 28 and 42 abut and providing the on switch is closed the electrical circuit is completed and a signal.is emitted.

The presence of the neck portion 54 ensures that movement of the upper portion of the tongue responsive to movement of the spine courses sufficient flexing of the tongue in the region of the screw contact 28 to provide adequate movement of screw contact 28 relative to contact 42. Thus movement detected at the tip results in movement of the contacting screw. Since the screw is fixedly attached to the metal of the tongue 44, when physiological lordosis of the back is lost, a signal is emitted due to the contacting of the contacts 42 and 28.

The screw contact 28 may be adjusted through the aperture 28 so that the distance between the contacts 28 and 42 when the spine is in physiological lordosis can be preset. This allows the device 10 to be set to emit a signal when a given degree of spinal flexion obtains and hence the device can be set to the individual needs of each patient.

In the embodiment shown, the housing is the reference means and the tongue the detection means. In its normal position the tongue is held by its resilience such that contacts 28 and 42 are in electrical contact.

Whenethe back is correctly maintained in an upright position, the tongue is deflected against its resilience from its normal position to a position in which the contacts 28 and 42 are separated and the electrical circuit is incomplete. As a result no sound is emitted from the buzzer 36. When the person wearing the device moves such that physiological lordosis is lost, the resilience of the tongue 12 courses flexing therewith in the region of the electrical contact 28, moving the contact 28 towards the electrical contact 42.

When contact between these two contacts is made the electrical circuit is completed and a signal is emitted.

Whilst the signal may be in the form of sound such as a buzz, in the case of a deaf person for example the signal may be in the form of light and the signal emitting means can be positioned remote from the device 10 where the signal can be seen by the wearer.

Claims

1. A device for monitoring spinal flexion in the human body, comprising reference means disposable in abutting relationship with the lower back of a human body, monitoring means movable relative to the reference means in response to flexion of the spine of said human body and signal means actuated when a predetermined degree of movement of the monitoring means occurs relative to the reference means.

2. A device as claimed in claim 1, wherein the monitoring means, in use, abuts a portion of the lower back at a location remote from the reference means.

3. A device as claimed in claim 1 or claim 2, wherein the monitoring means comprises an elongate member extending from the reference means.

4. A device as claimed in any of claims 1 to 3, wherein the monitoring means is hingedly attached to the reference means.

5. A device as claimed in any of the preceding claims, comprising biassing means which urge the monitoring means towards a position relative to the reference means at which the signal means is actuated.

6. A device as claimed in any of the preceding claims, wherein the monitoring means comprises a resiliently deformable member.

7. A device as claimed in claim 6 when appendent to claim 5, wherein the biassing means comprises a resiliently deformable portion of the monitoring means.

8. A device as claimed in any of the preceding claims, comprising an electrically operated signal device having a switch which is opened and closed by movement of the monitoring means relative to the reference means.

9. A device as claimed in claim 8, wherein the switch comprises electrical contacts on each of the reference means and the monitoring means.

10. A device as claimed in claim 9, wherein the contacts are adjustable in order to vary the degree of movement of the monitoring means necessary to actuate the switch.

11. A device as claimed in any of claims 8 to 10, wherein the switch is held in an open position when the spine is not in physiological lordosis and is closed upon a predetermined degree of movement of the monitoring means relative to the reference means.

12. A device as claimed in any of the preceding claims, wherein the signal means comprises means for generating an audible signal.

13. A device as claimed in any of the preceding claims, wherein the signal means comprises means for generating a visible signal.

14. A device as claimed in claim 12 or claim 13, wherein the signal means comprises delay means wherein the signal is generated only after flexion beyond the predetermined limit is maintained for a predetermined period.

15. A device as claimed in any of the preceding claims, wherein the reference means is adapted to be disposed in the region of the twelfth dorsal D12 vertebra, and the monitoring means is adapted to be disposed in the region of the first sacral S1 vertebra.

16. A device as claimed in any of the preceding claims comprising a belt to support the reference means in the region of the lower back.

17. A device for monitoring spinal flexion in the human body, substantially as herein described, with reference to, and as illustrated in, the accompanying drawings.