Abstract:
A support device ( 1 ) comprises a first support structure ( 6 ) which is conformable to an object to be supported, and a second support structure ( 2 ) which has an activated state in which the second support structure substantially locks the first support structure into a conformed shape, and supports tensile loading on the support device, and an inactivated state in which the first support structure is able to conform to an object.

Description:
[0001]    The present invention relates to support devices. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many objects requiring transport benefit from immobilisation in a secure manner in order to reduce the chances of damage occurring to the object concerned. Existing forms of support device include the use of polystyrene, or other foam material, blocks, and the use of airbags. However, such devices have limitations, particularly when irregularly shaped objects are considered. Airbags are able to conform to the shape of the object, but are not able to carry tensile loads, and are, therefore, unsuitable for many applications. 
         [0003]    In particular, immobilisation of patients having suspected spinal injuries is not served well by existing support devices. 
         [0004]    The aim of spinal immobilisation is to stabilise the spine of a patient by restricting mobility, and in so doing prevent exacerbation of spinal cord injury during extrication, resuscitation, transportation, and evaluation of such a trauma patient with suspected spinal instability. 
         [0005]    The most widely practiced method of cervical immobilisation is the use of a flat cervical collar. Such collars are essentially flat sections which are wrapped around the neck of a patient to form a tubular support section between the patient&#39;s head and neck. The flat sections are typically pre-shaped so as to follow generally the shape of the shoulders and head of the patient. 
         [0006]    However, there are a number of problems associated with existing designs of flat packed collar. 
         [0007]    Typically, the supporting edges are thin, for example, less than 5 mm thick. This means there can be high pressure at the support interface. Medical problems associated with long-term exposure to high pressures are well documented. However, of greater concern to the majority of collar wearers (who have not sustained a spinal injury but are being immobilised as a precautionary measure), is the increase of intracranial pressure which can be detrimental in the prognosis of head and brain injuries. 
         [0008]    The existing designs are available only in a limited range of fixed sizes. This means that the fit (that is, the interface at the supporting edges) of the collar and, therefore, the level of immobilisation provided are rarely optimised. Typically three sizes are provided to cover one unit of the population (infant to adult). However, despite there being three sizes available, the current range does not accommodate all patient variations to an acceptable level. Variations include neck sizes (circumferences, heights and postures), head shapes and chin profiles. 
         [0009]    The sizes offered by existing designs of collar are determined on the basis of neck height. Variations in neck circumference are accommodated in present designs by an adjustable fastener, which increases the size of the collar or support tube. One problem with this design of support device is that varying the circumference of the collar, or support tube, causes misalignment of the orientation of the pre-formed supporting edges. 
         [0010]    When conforming the flat packed collars to the patient it is being done against the shape memory of the material from which the collar is made. This makes the application process unnecessarily awkward and increases the chance of potentially dangerous patient disturbances. 
         [0011]    In addition, existing collars are uncomfortable, because the patient is fitted to the collar as opposed to the collar being fitted to the patient. The support mechanism is rigid, fixed in shape and geometry and, therefore, unable to adapt to the shape and form of the patient. Patients often describe the sensation of the collar digging in certain areas and observations of patients have recognised a phenomenon nicknamed the “fidget factor”; fidgeting within the collar to relieve or alter interface pressures and their positions. This fidgeting may exacerbate any existing injuries. 
         [0012]    Accordingly, it is desirable to provide a support device which overcomes the disadvantages of the previously considered devices, and which provides additional benefits. 
       SUMMARY OF THE PRESENT INVENTION 
       [0013]    According to one aspect of the present invention, there is provided a support device comprising a first flexible bag which defines a first volume, a second flexible bag which defines a second volume, and which is located within the first volume, a filler material which is located between the first and second bags within in the first volume, means for enabling inflation of the second flexible bag, and means for enabling evacuation of the first flexible bag. 
         [0014]    Such a support device may further comprise a protective shell which carries the first and second flexible bags. 
         [0015]    In one example, the filler material is provided by a plurality of spheres. The spheres may be of substantially solid polystyrene, or may be provided by hollow polystyrene balls. 
         [0016]    The means for enabling inflation of the second flexible bag may enable such inflation using pressurised gas. Alternatively, the means for enabling inflation of the second flexible bag may enable such inflation using pressurised fluid. Alternatively, the means for enabling inflation of the second flexible bag may enable such inflation using foam. 
         [0017]    According to another aspect of the present invention, there is provided a patient support device comprising at least one such support device. Such a patient support device may comprise a first part including a first such support device, and a second part including a second such support device. 
         [0018]    The first and second parts may be releasably engageable with one another, or may be flexibly engaged with one another. 
         [0019]    According to another aspect of the present invention, there is provided a method of supporting a part of a patient, the method comprising the steps of locating a support device embodying the present invention around a part of the patient to be supported, inflating the second flexible bag to a predetermined pressure, and evacuating the first flexible bag. 
         [0020]    According to another aspect of the present invention, there is provided a support device comprising a first support structure which is conformable to an object to be supported, and a second support structure which has an activated state in which the second support structure substantially locks the first support structure into a conformed shape, and supports tensile loading on the support device, and an inactivated state in which the first support structure is able to conform to an object. 
         [0021]    Such a support device may further comprise means for activating the second support structure from the inactivated state to the activated state. 
         [0022]    Such a support device may further comprise means for conforming the first support structure to an object. 
         [0023]    The means for conforming the first support structure to an object may comprise means for inflating the first support structure. 
         [0024]    The means for activating the second support structure may include means for evacuating the second support structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a cross sectional view of a support device embodying the present invention; 
           [0026]      FIG. 2  is a cross sectional view of the device of  FIG. 1  in use; 
           [0027]      FIG. 3  is a cross sectional view of another embodiment of the present invention; 
           [0028]      FIG. 4  is a plan cross sectional view of a neck restraint incorporating support devices embodying the present invention; and 
           [0029]      FIG. 5  is a cross sectional view of a further embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    The principles of the present invention will now described with reference to a cervical support collar for immobilising a patient having suspected spinal injury. It will be readily appreciated that these principles can be embodied by support devices that are used to support other objects, particularly object of irregular shape. 
         [0031]      FIG. 1  is a cross sectional view of a support device  1  embodying the present invention. The support device  1  comprises a first flexible bag  2  which defines a first enclosed volume  3  therein. A second flexible bag  6  is located within the first enclosed volume  3  within the first flexible bag  2 , and defines a second enclosed volume  7 . A filler material  10  is provided inside the first enclosed volume  3  and outside of the second enclosed volume. That is, the filler material is provided between the first and second bag  2  and  6 . In the embodiment shown in  FIG. 1 , a protective shell  12  supports the first and second bags and filler material. In the unused condition as shown in  FIG. 1 , air in the first and second bags  2  and  6  contain air at substantially atmospheric pressure, such that the first and second bags  2  and  6 , and the filler material  10 , are substantially flexible. 
         [0032]    The first and second bags  2  and  6  are preferably of a tear resistant flexible membrane approximately 0.25 mm thick, and may be formed using laser, or radio frequency (RF), welding techniques. Preferably, the protective shell is of a semi-rigid polymer material and is preferably approximately 2 mm in thickness. 
         [0033]      FIG. 2  illustrates the device of  FIG. 1  in use supporting an object  13 . It will be appreciated that the profile of the object in  FIG. 2  resembles that of a patient&#39;s neck. It is to be noted that this application is merely exemplary, and that the support device may be used to support any object or part of a patient that requires support or immobilisation. 
         [0034]    In order to support the object  13 , the second bag  6  is inflated. Such inflation can be achieved using a pressurised gas supply, preferably air. Alternatively, a liquid, suspension, emulsion or gel could be used to increase the volume of the second bag  6 . Inflating the second bag  6  causes the support device  1  to conform to the shape of the object  13 . The first bag  2  and the filler material  10  contained therein are thereby also formed to the shape of the object  13 . 
         [0035]    After the second bag  6  has been inflated to a desired pressure (for example, approximately 1 to 32 psi, approximately 6.8 kPa to 220 kPa), the first bag is evacuated in order to create at least a partial vacuum in the first enclosed volume  3 . Creating such a partial vacuum causes the filler material  10  to be held firmly in place in the conformed shape by the first and second bags  2  and  6 . In such a configuration, the support device holds the object  13  substantially rigidly. The evacuated first bag  2  provides the rigidity for the support device  1 , and the second bag  6  provides additional support and the conformity of shape. 
         [0036]    The inflation of the first bag  2  and the evacuation of the second bag  6  can be performed by any appropriate means.  FIG. 3  illustrates a cross sectional view of another support device that embodies the present invention. The support device  1  of  FIG. 3  includes an inflation valve  14 , and an evacuation valve  16 . The inflation valve is provided in order to enable the second bag  6  to be inflated. The evacuation valve  16  is provided in order to enable the first bag  2  to be evacuated. The valves  14  and  16  are preferably provided by non-return valves that can be manually opened when the support device is to be removed. 
         [0037]      FIG. 4  is a plan cross sectional view of one exemplary neck support collar incorporating the “dual bag” concept of the present invention. In this example, the neck support is provided in two parts: a front part  20  and a rear part  30 . The front part  20  comprises a front protector shell  22 , first and second flexible bags  23  and  24 , and a filler material  25  provided between the first and second bags  23  and  24 . An inflation valve  26  is provided in order to allow inflation of the second bag  24 , and an evacuation valve  27  is provided in order to enable evacuation of the first bag  23 . The first and second bags  23  and  24  of the front part will be referred to as front vacuum bag  23  and front inflation bag  24  for the sake of clarity. 
         [0038]    It will be readily appreciated that a support device embodying the present invention may be provided by any number of dual bag elements. 
         [0039]    The rear part  30  of the neck support collar comprises a rear protector shell  32  which carries a first bag  33 , a second bag  34  and filler material  35  located between the first and second bags  33  and  34 . An inflation valve  36  is provided to enable inflation of the second bag  33 , and an evacuation valve  37  is provided in order to enable the second bag  34  to be evacuated. 
         [0040]    The front and rear protector shells  22  and  32  are preferably preformed in broadly curved shapes for fitting around a patient&#39;s neck. The protector shells  22  and  32  may be provided in a flat configuration and bent into shape when used. In one example, the inflation of the second bag causes the protector shells to curve into an appropriate shape. 
         [0041]    The front and rear parts  20  and  30  of the neck support device shown in  FIG. 4  are held together using corresponding fasteners  28  and  38 . Preferably, these fasteners are provided by a hook and loop fastener device but could be provided by any appropriate means, such as, for example, a ratchet or other sliding mechanism. 
         [0042]    In order to support the head and neck of a patient, the rear part  30  is slid in behind the neck, and the front part  20  is then attached to the rear part  30  using the attachment fasteners  28  and  38 . The rear inflation bag  34  is then inflated. After inflation, the rear vacuum bag  33  is evacuated. The inflation and evacuation procedure is carried out for the front inflation bag  24  and front vacuum bag  23  respectively. 
         [0043]    The multi-part design of support device enables the device to provide support even if one of the parts is removed, for example to enable to a patient&#39;s airway. 
         [0044]    In this way, a rigid support device can be provided around the neck of the patient, both to the front and to the rear of the patient. The device is straightforward to fit to the patient, and provides substantially increased immobilisation over previously considered designs. This immobilisation is provided because the inflation bags conform the support device to the exact shape of the patient&#39;s neck, and the filler material and vacuum bag provide a substantially rigid structure conformed to that shape. 
         [0045]    The filler material may be provided by a large number of small (approximately 2 mm in diameter) polystyrene beads. Such beads could be solid or hollow. 
         [0046]    One possible disadvantage of the use of polystyrene beads is that the beads may not be evenly distributed throughout the first bag. Accordingly,  FIG. 5  illustrates a further embodiment of the present invention which aims to overcome such a disadvantage. The embodiment of  FIG. 5  comprises a protector shell  42  which carries a vacuum bag  43 , and an inflation bag  44 . Filler material in the form of polystyrene beads  45  is provided, as airbag and the vacuum bag. In addition, the embodiment of  FIG. 5  comprises a mesh of flexible material  46  which serves to retain the filler material substantially evenly distributed across the face of the airbag  43 . This flexible mesh thereby enables the support device to be used even if the device has been stored in a manner which would otherwise lead to the uneven distribution of the filler material. Subdividing the first bag into compartments could also provide the function of the mesh. Such compartments could be individually evacuated, or could feature valves therebetween to enable all of the compartments to be evacuated during the same evacuation stage. 
         [0047]    Although the present invention has been described primarily in connection with neck support devices, it will be readily appreciated that the principles of the invention, namely the use of an inflation bag in combination with a vacuum bag and filler material, can be applied to supporting any part of a patient. For example, an appropriately sized device could be used to immobilise fractured limbs and joints. 
         [0048]    A particular advantage of a support device embodying the present invention is that a single device can be used for a range of patient sizes. 
         [0049]    Furthermore, it will be readily appreciated that such a device could be used to support any object that requires substantially rigid support. Embodiments of the present invention are particularly suited to the support of variable or unevenly shaped objects.