The present invention relates to a spinal covering device and to a method for protecting neural spinal elements following a spinal procedure.
Neural spinal elements can be exposed after various spinal procedures such as laminectomy, spinal decompression, spinal release, osteotomy and discectomy. Increase in the space available for neural elements can also be required in case of spinal stenosis. When a fusion procedure is performed, placing bone graft on exposed neural elements can cause undue neural compression. The surface available for fusion is reduced since the bone graft is laid only on the remaining bone surfaces, so that bone healing can be unsuccessful or inadequate. Bone graft applied on the remaining bone surfaces can also be displaced and can potentially injure the spinal neural elements. In addition, scarring and bone regrowth can later compress the exposed neural elements and as such necessitate additional revision surgery. The presence of scar and/or bone regrowth over the neural elements can significantly increase the risk of complications and injury to the neural elements during revision surgery.
Even when no fusion procedure is performed, scarring and bone regrowth can later compress the exposed neural elements and cause major symptoms to the patient or necessitate the need for additional surgery to decompress the neural elements. Some surgeons have applied biological non-rigid material to reduce scar formation but such a procedure generally does not prevent mechanical compression by overlying soft or bony tissues. Other surgeons have used laminoplasty procedures to expand the spinal canal using the patient's own vertebral posterior arch that is displaced and stabilized, in an attempt to prevent scar formation in addition to provide greater space for neural elements. However, the coverage and space available for neural elements are limited by the patient's bone morphology. These procedures also usually leave an uncovered area with exposed neural elements on the side of bone cut, which disrupts the continuity of the posterior arch. Also, they are usually technically difficult to perform and can lead to complications such as fractures and failure of fixation, and the extent of final coverage and decompression is generally difficult to predict or control with precision.
Accordingly, improvements are desirable.
It is an object of the present invention to provide an improved spinal covering device and method of protecting exposed neural spinal elements.
In accordance with the present invention, there is provided a spinal covering device for covering exposed neural spinal elements after a spinal procedure, the device comprising a body at least substantially free of openings and extending longitudinally from a first end to a second end, and first and second support planes extending longitudinally along the body, the first and second support planes being adapted to overlay or abut remaining tissues on opposite sides of the exposed neural spinal elements such that the device forms a spinal canal portion protecting the neural spinal elements, the device having an inner surface at least partially defining an inner surface of the spinal canal portion and an outer surface opposite of the inner surface, at least the outer surface allowing bone graft deposition or bone fusion thereon.
Also in accordance with the present invention, there is provided a spinal covering device for covering at least one exposed neural spinal element after a spinal procedure comprising an arcuate shaped body at least substantially free of openings, the arcuate shape being defined from a first longitudinal side to a second longitudinal side of the body, and first and second support planes respectively extending from the first and second longitudinal sides, the first and second support planes being adapted to overlay or abut remaining vertebral bones such that the device extends over and spaced apart from the exposed neural spinal elements to form a spinal canal portion, the device having an inner surface at least partially defining an inner surface of the spinal canal portion and an outer surface opposite of the inner surface, at least the outer surface including a bone extender, enhancer or substitute that has osteoconductive, osteoinductive or osteogenic properties.
Still in accordance with the present invention, there is provided a method for protecting at least one exposed neural spinal element following a spinal procedure, comprising positioning a spinal covering device on remaining soft or bony tissues on each side of the at least one exposed neural spinal element or in abutment with the remaining bony tissues to extend over and spaced apart from the at least one exposed neural spinal element, and contacting bone graft or bone substitute material added over or included in an outer surface of the spinal covering device with the remaining bony tissues to allow the bone graft or bone substitute material to fuse with the remaining bony tissues.
Reference will now be made to the accompanying drawings, showing by way of illustration a particular embodiment of the present invention and in which:
a is a perspective view of a spinal covering device in accordance with a first embodiment of the present invention;
b is a perspective view of a spinal covering device in accordance with another embodiment of the present invention;
a is a top view of a portion of a spinal column with a spinal covering device such as shown in
b is a top view of a portion of a spinal column with a spinal covering device such as shown in
a is a perspective view of a spinal covering device in accordance with another embodiment of the present invention;
b is a perspective view of a spinal covering device in accordance with another embodiment of the present invention;
a is a perspective view of a spinal covering device in accordance with a further embodiment of the present invention; and
b is a perspective view of a spinal covering device in accordance with a further embodiment of the present invention.
A spinal covering device for covering exposed neural spinal elements after a spinal procedure such as laminectomy, spinal decompression, spinal release, osteotomy and discectomy is described herein. The removal of soft or bony tissues at one or more vertebral levels along the spinal column leaves the neural spinal elements exposed and susceptible to physical trauma. Products such as gelatine foam or fat do not provide a sufficient barrier to prevent potential physical trauma. The spinal covering device advantageously rests on or against remaining soft or bony tissues to minimize the contact between the device and surrounding neural spinal elements by forming a spinal canal portion containing the spinal element. Such reduced contact minimizes adhesion formation between the neural tissues and the device itself.
Referring to
Referring to
In a particular embodiment, the first and second support planes 17, 18 and 117,118 overlay opposite sides of the remaining vertebral bones.
In a preferred embodiment, the spinal covering device 10,110 is rigid.
The device 10,110 advantageously increases the surface available for bone fusion and for the deposition of bone graft or bone substitute. In a particular embodiment, the device 10,110 promotes or enhances bone growth and healing, such as by being entirely made of or by having the outer surface 20,120 including a bone fusion enhancing or promoting substance, e.g. a bone extender, enhancer or substitute that has osteoconductive, osteoinductive or osteogenic properties. Such substance include, for example, cadaver bone, bone morphogenetic protein, demineralized bone matrix, collagen, suitable polymers, suitable ceramics such as natural coral (calcium carbonate) or coralline hydroxyapatite, or suitable composites such as hydroxyapatite-tricalcium phosphate. Preferably, the device 10,110 becomes incorporated into the remaining bony tissues. More particularly, the remaining bony tissues fuse with the contacting outer surface 20,120 of the device, forming a new spinal canal.
In a particular embodiment the inner surface 21, 121 adjacent the neural spinal elements and defining the inner surface of the spinal canal portion prevent scar formation and bone regrowth. For example the inner surface 21,121 of the device 10,110 can be advantageously impregnated or coated with a drug or substance suitable for preventing scar formation and bone regrowth. As such, the inner surface 21,121 of the device 10,110 may contain an absorptive, saturatable or impregnatable material suitable for acting as a carrier of a drug or substance for preventing scar formation and bone regrowth. Alternately, the device 10,110 may be used in combination with a suitable element or substance preventing scar formation and tissue growth, for example absorbable gelatine, placed between the device 10,110 and the neural spinal element to prevent adhesion.
The actual dimensions of the device 10,110 will vary depending on the particular surgical procedure and on the patient's anatomy. The device is preferably prepared in a size and shape to accommodate a particular spinal procedure. It is further contemplated that the overall length of the device 10,110 can be varied to accommodate spinal procedure involving more than one vertebra. It is also contemplated to provide the device 10,110 in a relatively large dimension for cutting to adequate size upon use.
It is contemplated that the device 10,110 may be prepared from any number of adequate materials known in the art. Preferably, the material is biocompatible. For example, the device can be prepared from an adequate type of ceramic, composite, coral, polymer or porous metal, with the outer surface 20,120 including a bone fusion enhancing or promoting substance, e.g. bone extender, enhancer or substitute that has osteoconductive, osteoinductive or osteogenic properties, as discussed above. In a particular embodiment, the device 10,110 is made of a suitable plastic or ceramic and includes an outer layer of bone morphogenetic protein defining the outer surface 20,120.
The attachment means contemplated for use with the device 10, 110 of the present invention can take any number of forms. In a preferred embodiment, the attachment is to bone. Bone attachment contemplated within the scope of this invention include, but are not limited to, attachment to adjacent spinous processes and lateral attachments such as to lamina facets, transverse processes, articulating processes or the like. It is desirable that no contact is made with the neural elements. Preferably, the attachment means does not extend into the spinal canal or neuroforamen to an extent that would make contact with the dura or nerve roots likely.
In a particular embodiment, the attachment means includes surgical wires, staples, pins, screws or the like. The pins, wire, screws or other attachment means contemplated within this invention are preferably prepared from surgical steel, tungsten, titanium or other suitable materials.
An exemplary application of the device 10,110 is provided in
Turning to
The device 10,110 can also be connected rigidly or non-rigidly to at least one adjacent vertebra to recreate spinal stability.
The spinal covering device 10, 110 can also be used to overlay several vertebrae by using a plurality of adjacent single level spinal covering devices such as 110, as shown in
Referring to
a shows a planar spinal covering device 310 according to an alternate embodiment of the present invention. The device 310 includes a planar body 311 preferably at least substantially or completely free of openings which extends longitudinally along an axis 12 from a first end 313 to a second end 314 for covering exposed neural spinal elements 26 after a spinal procedure. The planar spinal covering device 310 has also a first support plane 317 and a second support plane 318 which are continuous with the planar central portion of the body. The device 310 has an outer surface 320 opposite the side of the device 30 which defines the inner surface of the spinal canal portion, the outer surface 320, and if required, end surfaces, allowing bone graft deposition or bone fusion thereon.
Turning to
a shows a triangular spinal covering device 510 according to an alternate embodiment of the present invention. More particularly, the device 510 includes a triangular shaped body 511 preferably at least substantially or completely free of openings and extending longitudinally from a first end 513 to a second end 514 for covering exposed neural spinal elements 26 after a spinal procedure. The triangular spinal covering device 510 also has a first support plane 517 and a second support plane 518 extending from a respective one of the longitudinal sides of the body 511. The device 510 has an inner surface 510 forming an inner surface of the spinal canal portion, and an outer surface 520 and if required, end surfaces, allowing bone graft deposition or bone fusion.
Turning to
All of the spinal covering devices 210, 310, 410, 510 and 610 can include an inner surface preventing scar formation and bone regrowth and be used in any appropriate one of the applications shown and described and variants thereof.
The present application claims priority on U.S. Provisional Patent Application No. 61/193,894 filed Jan. 6, 2009, the entire contents of which is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CA2010/000007 | 1/6/2010 | WO | 00 | 7/6/2011 |
Number | Date | Country | |
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61193894 | Jan 2009 | US |