Process for manufacture of laminate shells

An orthosis may be made by providing a laminate material having a flexible foam material and a substantially rigid plastic sheet material sandwiched between a pair of soft flexible sheet materials. A body support is formed by heating the laminate material under conditions of pressure to soften the laminate to a pliable state, cutting the laminate to a desired shape to yield a pattern corresponding to a desired shape of the body support, providing a form corresponding to a desired configuration of the body support and positioning the pattern on the form in a pliable state, applying a negative pressure to conform the pattern.

FIELD OF THE INVENTION

This invention relates generally to methods for producing medical orthoses. More particularly, this invention relates to the production of laminate shells for spinal braces. The shells have sufficient rigidity to serve a support function, yet which do not unduly constrict breathing of the patient wearing the brace and offer improved comfort.

BACKGROUND AND SUMMARY OF THE INVENTION

Improvement is desired in the field of spinal braces. Braces are typically constructed using rigid materials, such as being formed by vacuum molding plastic. Such braces have good support characteristics, but, are disadvantageous in that they are relatively heavy and may constrict respiration of the patient and be uncomfortable to wear.

The disclosure relates to a process for the manufacture of improved orthosis, particularly spinal orthosis, that are relatively lightweight and supportive, and which are believed to offer improved comfort and reduced constriction of respiration as compared to conventional spinal braces.

In a preferred embodiment, the process includes the steps of providing a laminate material having a flexible foam material and a substantially rigid plastic sheet material sandwiched between a pair of soft flexible sheet materials. A body support is formed by heating the laminate material under conditions of pressure to soften the laminate to a pliable state, cutting the laminate to a desired shape to yield a pattern corresponding to a desired shape of the body support, providing a form corresponding to a desired configuration of the body support and positioning the pattern on the form in a pliable state, applying a negative pressure to conform the pattern.

DETAILED DESCRIPTION

With reference to the drawings, the invention relates to the manufacture of a spinal brace10particularly configured to serve as a thoracic-lumbar-sacral orthosis (TLSO). The brace10includes a posterior support12and an anterior support14. The supports12and14are each made of a laminate material16(FIG. 2) that enables the supports12and14to have sufficient rigidity to serve a support function, yet to be relatively lightweight and to avoid undue constriction of breathing of the patient wearing the brace. The brace10also preferably includes a pair of strap assemblies18. The brace10is preferably positioned on a patient while supine.

It will be understood that the brace10may be otherwise configured for providing an orthosis suitable for treating other portions of the spine, such as the cervical portions, as well as fewer portions, such as a configuration as a lumbar-sacral orthosis (LSO). The brace10may also be configured to impart a particular orientation, such as a flexion, extension, or a neutral orientation to the spine.

The supports12and14are each preferably of lightweight laminate construction and have sufficient rigidity to serve a support function, while also having a degree of flexibility sufficient to permit substantially unrestricted contractions and expansions of the torso of the user associated with breathing.

With reference toFIG. 2, the supports12and14each include an interior or patient engaging surface20and an exterior surface22. The surfaces20and22are preferably each made of a soft material that is capable of engaging hook material in the context of mating hook and loop materials, such as VELCRO. However, other soft, preferably fabric materials may be used. Sandwiched between the surfaces20and22is a foam material24and a plastic sheet26, with such components being bonded to one another to form a unitary laminate material.

The foam material24is preferably a sheet of about ⅛ inch thick closed cell foam material. The sheet26is preferably a sheet of about 1/16 inch thick low density polyethylene. The components of the supports12and14are preferably bonded to form the laminate material as by vacuum molding with adhesive placed between each layer. Alternatively, the supports are made by flame lamination without the use of adhesive. In flame lamination, the layers are passed over an open flame to partially melt the foam to create a thin layer of molten polymer. The molten polymer serves to adhere the materials together on both sides of the foam. The supports may be heated if desired, as by a heat gun or oven, to soften them so that they may be custom fit to the patient. However, a particularly preferred method for configuring the supports12and14made of the laminate16is described below in connection withFIGS. 7-11.

With additional reference toFIGS. 3 and 4, the posterior support12is made of the laminate16and generally shaped to conform to and wrap around a posterior portion of a patient. An elongate aperture30is provided on the support at a central location corresponding to the location of the spinal column of a patient. The support12may include additional rigidifying structure adjacent the aperture30to rigidify the support at locations immediately lateral the spinal column of the user. This may be accomplished as by incorporating additional rigidifying materials within the laminate, such as rigid strips of ABS plastic, along both sides of the aperture30. Alternatively, as seen inFIG. 3, this may be accomplished by including an external rigidifying member32.

The rigidifying member32preferably provides additional rigidity along the sides of the aperture30and may be provided as rigid members such as aluminum or composite rods or the like. InFIG. 3the rigidifying member32is provided by an aluminum rod configured to be substantially U-shaped and secured to the support as by clamps34affixed to the support12using fasteners36, such as plastic screws or rivets. The use of aluminum rods, or other rigid yet malleable material, is desirable in that it may be adjusted to correspond to desired kyphotic or lordotic curves. For example, it may be desirable to shape the rigidifying member32to impart desired curves to regions of the spinal column and to periodically change these curves.

The support12may also include a thoracic support38extending above and adjustably positionable relative to the support12for supporting the kyphotic curve imparted to the thoracic region of the spinal column. The support38may be made of the laminate16and may be mounted relative to the support12as by use of a U-shaped portion of an aluminum rod40adjustably securable to mounting blocks42located on the upright ends of the rigidifying member32. Alternatively, individual or separate sections of aluminum rods may be used to provide the support38.

With additional reference toFIGS. 5 and 6, the anterior support14is made of the laminate16and is generally shaped to conform to and wrap around a anterior portion of a patient, and to slightly overwrap the edges of the anterior support12. If desired, a sternal pad system50may be attached to the anterior support14for limiting flexion or for hyperextending the upper thoracic region of a patient. The sternal pad system50includes a pad member52, a pair of side mounting members54, and a central adjustable mounting system56.

The pad member52is preferably made of the laminate16. The pad member52is substantially U-shaped and configured for cradling the sternum of a user. The side mounting members54are preferably provided by elongate strips of a rigid plastic material, such as ABS plastic, and configured to be statically or adjustably positioned. For example, an upper end of the mounting members54is preferably angled so that they can be reversed to change the mounted position or angle of the pad member52relative to the support14. The mounting members54are preferably secured to the support14and the pad member52as by fasteners58, most preferably adjacent the exposed edges of the support14and the pad member52.

The central adjustable mounting system56(FIG. 5) preferably includes a support mounting plate60, a pad member mounting plate62, and a rigid extension64that spans between the plate60and the plate62. Fasteners66may be used to mount the plates60and62, the plates60and62preferably being made of a lightweight plastic material, such as ABS plastic. The plate60preferably mounts to a central portion of the support14and includes a mounting block68for adjustably receiving the extension64. In this regard, the extension64may be provided as by a U-shaped portion of an aluminum rod70adjustably securable to the mounting block68so as to permit adjustment of the height of the pad member52relative to the support14. Also, the rod70may be shaped to adjust the position of the pad member52. The central portion of the U-shaped rod70is preferably secured to the plate62as by fasteners or the like.

The strap assemblies18each preferably include first and second straps80and82connected at common ends to a common securement strap84having a hook material on the interior surface thereof so as to be positionable in releasable engagement with the exterior surface22of the laminate16of the anterior support14, as seen inFIG. 1. The opposite free ends of the straps80and82include a hook material on the interior surface thereof so as to be positionable in releasable engagement with the exterior surface22of the laminate16of the anterior support12. D-rings86or the like may be located on the ends of the straps80and82to facilitate grasping thereof. Slides or chafes88are preferably secured to the exterior of the posterior support12, with the straps80and82passed therethrough.

To install the brace10, the user places the posterior support12around the posterior body portions and, while holding this in place, places the anterior support14over the anterior body portions, and slightly overlapping the anterior support12. This process is facilitated by having one of the strap assemblies secured to both of the supports12and14. Next, the user may secure both of the strap assemblies18by pressing the securement straps84into firm engagement with the surface22of the posterior support, and then pulling on the D-rings86, one at a time or two at a time, and then securing the hook material associated with such ends in engagement with the loop material of the exterior surface22of the anterior member14. The user may adjust the compression and fit of the brace10by adjusting the locations and orientations of the securement straps84or the opposite free strap ends, or both.

In accordance with another aspect of the disclosure, there is described a preferred process for configuring the laminate16into the supports12and14. The process advantageously enables the laminate16to be formed, while avoiding undesirable delamination of the laminate and wrinkling of the patient engaging surfaces20and22. The process is substantially the same for the supports12and14. Thus, the process will be described only in connection with manufacture of the support14.

With reference toFIGS. 7-11, the process includes a step100in which the laminate16used to provide the support14is heated under conditions of pressure to soften the laminate16. Step100is preferably accomplished as by use of a heated press101of the type commonly used to apply decals and the like to t-shirts and other clothing. For this step, the laminate16is preferably subjected to a temperature of from about 285 to about 310° F. at a light pressure to inhibit wrinkling for a time period of from about 4 to about 8 minutes.

In step102, the heated and pliable laminate from step100is cut to a pattern103corresponding to the support14and the excess material recycled or otherwise disposed. Cutting of the laminate to the desired pattern103is preferably accomplished as by use of a die-cut press or stamp press or the like having a continuous knife edge that is pressed against the material to be cut in the manner of a cookie cutter to provide the desired outline or pattern to the laminate16. Step102is preferably accomplished relatively quicky so that the pattern103remains in a substantially pliable state. It has been observed that the laminate16from step100remains substantially pliable for a time period of up to about 6 minutes, which time has been observed to be sufficient to accomplish all of the process steps described herein. Alternatively, it will be understood that the laminate may be cut into the pattern prior to heating it per step100.

In step104, the pliable pattern103is positioned on a form105corresponding to the body portion with which the support14is to be used. As will be understood, the form105may be of various dimensions and may be a standard form or a custom form corresponding to a specific patient. The form105is preferably a hard foam or a hollow plastic form having a solid and relatively hard surface. However, as described below, the form105may be configured to have a plurality of small apertures in the region where the pattern103is to be applied for application of negative pressure for forming the pattern103into the desired shape for the support104.

In step106, an airtight and flexible enclosure, such as a plastic bag107is placed around the form105having the pattern103thereon. An open end108of the bag107is sealingly secured around a vacuum hose109located to extend into the open end108of the bag107. The hose19is connectable to a vacuum source V for supplying a negative pressure to the interior of the bag107. Under the conditions of negative pressure within the bag107, the pattern103is snugly conformed to the shape of the portion of the form105against which it is positioned. The vacuum source V preferably supplies a negative pressure of from about −10 to about −20 inch pounds mercury and this pressure is preferably maintained for a time period of from about 4 to about 6 minutes. Alternatively, the form105may be configured to have a plurality of small apertures in the region where the pattern103is to be applied. The end of the form105would be closed, except for a passage for the hose109for application of negative pressure for forming the pattern103into the desired shape for the support104.

In step110, the pattern103is cooled to a non pliable state negative pressure is applied to conform it to the form. For example, cooling fluid, such as air is applied, preferably by an exterior fluid supply, such as an air hose111, to cool the pattern103while negative pressure is applied via the hose109. For example, relatively cool air is supplied from a compressed air source as by spraying the air over the pattern103for a time sufficient to cool it so that it retains the formed shape.

The foregoing description of certain exemplary embodiments of the present invention has been provided for purposes of illustration only, and it is understood that numerous modifications or alterations may be made in and to the illustrated embodiments without departing from the spirit and scope of the invention as defined in the following claims.