Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
2001-08-28
2004-01-20
Philogene, Pedro (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
C606S083000, C606S167000
Reexamination Certificate
active
06679886
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to tools and procedures, which, in use, form cavities in interior body regions of bones, particularly in vertebrae, for diagnostic or therapeutic purposes.
BACKGROUND OF THE INVENTION
Certain diagnostic or therapeutic procedures require the formation of a cavity in a bone mass. This procedure can be used to treat any bone, for example, bone which due to osteoporosis, avascular necrosis, cancer, or trauma, is fractured or is prone to compression fracture or collapse. These conditions, if not successfully treated, can result in deformities, chronic complications, and an overall adverse impact upon the quality of life.
For example, as described in U.S. Pat. Nos. 4,969,888, 5,108,404, and 5,827,389, an expandable body is deployed to form a cavity in cancellous bone tissue, as part of a therapeutic procedure that fixes fractures or other abnormal bone conditions, both osteoporotic and non-osteoporotic in origin. The expandable body compresses the cancellous bone to form an interior cavity. The cavity receives a filling material, which provides renewed interior structural support for cortical bone.
U.S. Pat. No. 5,062,845 described a surgical tool for preparing a graft site between opposing vertebra. The tool has a distal end with external dimensions sized to be passed through the patient's anatomy to a point of entry on the spine. At each incremental extension, the surgeon rotates the handle so that the blades cut out a large chamber equal to the size of the diameter of the extended extendable blades located on the distal end of the tool. After each such cut, the handle is turned to progressively increase the diameter of the cutting edges of blades until a chamber of desired size (up to the diameter of the fully extended blades) is formed. Intermittently, between enlarging the diameter of the cavity, the surgeon may retract the blades and remove the tool to flush the cavity being formed.
U.S. Pat. No. 5,512,037 describes a percutaneous surgical retractor having an outer sleeve with an open beveled configuration and having an angle defining a leading edge on the distal end of the outer sleeve to facilitate percutaneous insertion of the retractor; a blade slidable within said outer sleeve between at least a deployed position extending beyond the distal end of the outer sleeve and a retracted position disposed within the outer sleeve, the blade having a deployable memory curved distal end.
SUMMARY OF THE INVENTION
The invention provides new tools and methods for creating cavities in cancellous bone, for example but not limited to vertebroplasty, and for treating these cavities by injecting appropriate treatment materials, i.e., bone paste, cement, autograft, allograft, etc. The tools include a probe that introduces a passageway to the cancellous area, a cannula which expands the hole in the bone and provides a passageway for a tamp or flexible curette to push or tamp back the cancellous structure to form the cavity, and a syringe which fills the cavity with appropriate treatment material. These tools advantageously work together.
The Probe:
The probe is a long slender body with a sharp tip and a handle. The outer diameter of the long slender body is sufficient to fit inside the cannula. The tip of the probe may contain a drilling tip, a sharp point, a serrated edge, or a combination thereof. In a preferred embodiment, the probe has a changeable sharp tip firmly held by a probe sheath that provides strength and gently sloping surfaces useful for wedging or pushing away bone. In another embodiment, the probe and sheath are integrated into a single piece construction. In use, the cannula may be pre-loaded onto the probe so that the handle of the probe need not be removed to insert the cannula. In one embodiment, illustrated in
FIGS. 2A and 2B
, the probe body has depth markings. These markings can help the physician determine the position of the cannula as it is being placed in the bone. In addition, the markings may also indicate whether the positioning of the cannula is also moving the probe out of the position selected by the physician.
In one embodiment, the handle is detachable from the long slender body so that the cannula may be placed onto the probe after the probe has been positioned in the bone. The detachable handle may be designed to be disposed of after completion of the surgical procedure. For instance, the handle may be fabricated from low cost polymer material, have a simplified attachment mechanism, or both so that replacement of the disposable handle is relatively inexpensive. In one embodiment, the disposable handle is made from plastic material. One advantage of this embodiment is that the plastic would provide radio-lucent to better view the treated area. Fabrication of the handle may be by machining, molding, or any other method. The handle helps provide a better grip and greater control of the probe during its initial positioning. In addition, the handle also may be used to help remove the probe after the cannula is positioned.
Other items described herein also may be designed to be disposable after use. For instance, the handle for the cannula may likewise be made of low-cost polymer material using any suitable fabrication method. Moreover, many of the tools described herein may be designed with a limited or single use in mind. In one embodiment, for instance, the many of the tools in a kit for performing vertebroplasty may be disposed of after completion of the surgical procedure. In a preferred embodiment, the cavity creating tamp is reuseable while the other tools in a kit provided to the surgeon are disposable.
The probe guides the cannula, while the cannula enlarges the hole in the bone and is firmly anchored in this hole. Once the cannula is in its desired position, the probe may be removed by withdrawing it out of the end of the cannula not engaged with the bone.
The Cannula:
The cannula is a guiding tube that, in an embodiment, has a cutting edge on the distal end thereof. The cannula is essentially a long cylindrical tube which guides and holds the tamp in place while the tamp is being used to form the cavity. The cannula preferably has a handle to facilitate rotation and working of the cannula into the bone. More preferably, the cannula has a handle with a hole extending there through that is in alignment with and continuous with the hole extending through body. In one embodiment, the cannula handle is detachable. As described above for the probe handle, the detachable handle may be designed to be disposed of after completion of the surgical procedure. The handle of this embodiment may be fabricated from low cost polymer material so that replacement of the disposable handle is relatively inexpensive. Suitable materials and manufacturing methods for the handle of this embodiment are similar to those described above.
The cannula body preferably is tubular with the hole extending the entire length of the tube. The hole is advantageously, but not necessarily, circular. The hole is configured and adapted so that other tools, such as those described herein, may be inserted into the bone through the cannula hole. It is further preferred that the hole in the cannula allows the bone tamp to be freely rotatable. In an alternative embodiment, either the cannula, the tamp, or both, may be designed to impose a limited range of rotation. For instance, the cannula or probe may have stops that allow the tamp to be rotated within a certain range, but no further. In one embodiment, the limited range of rotation may be adjustable so that the range of rotation may be selected by the physician either before or during the surgical procedure.
In a preferred embodiment, the interior wall of the cannula defines an open cylinder having an inner diameter between about 3 mm and about 7 mm, more preferably between about 3 mm and about 6 mm, and most preferably between about 4.2 mm and about 5 mm. In one embodiment, the exterior wall of the cannula defines a cylinder that is between about 5 mm and about 9 mm. In a more preferred emb
Binder Larry
Kephart Douglas
Lehmicke Mike
Thongpreda Nisra
Weikel Stuart
Pennie & Edmonds LLP
Philogene Pedro
Synthes (USA)
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