Osteotome with a distal portion for simultaneous advancement and articulation
Medical devices for creating or expanding a cavity within bone of a patient are disclosed. In some circumstances, a medical device, such as an osteotome is designed to facilitate simultaneous advancement and articulation of a distal portion of the osteotome. Simultaneous advancement and articulation of the distal portion may reduce one or more forces on the distal portion of the osteotome relative to other methods in which advancement and articulation are separated in time, thereby decreasing the risk of breakage or other damage to the osteotome.
1. A medical device for creating or expanding a cavity within bone of a patient, the medical device comprising:
a housing;
a first shaft that is threadably coupled to the housing;
a second shaft that is threadably coupled to the first shaft;
a third shaft that is coupled to the first shaft such that a proximal portion of the third shaft moves axially with the first shaft; and
a fourth shaft that is coupled to the second shaft such that a proximal portion of the fourth shaft moves axially with the second shaft;
wherein the medical device is configured such that rotation of the first shaft relative to the housing in a first direction results in simultaneous displacement of a distal tip of the medical device in a distal direction relative to the housing and displacement of the distal tip of the medical device in a direction that is lateral to a longitudinal axis of the medical device, and
wherein the medical device is configured such that rotation of the first shaft relative to the housing results in (1) axial displacement of the first shaft and the proximal portion of the third shaft relative to the housing at a first rate and (2) axial displacement of the second shaft and the fourth shaft relative to the housing at a second rate that is different from the first rate.
2. The medical device of claim 1 , wherein the second shaft is coupled to the housing to prevent rotation of the second shaft relative to the housing.
3. The medical device of claim 1 , wherein:
the first shaft comprises exterior threads that threadably engage threads of the housing; and
the second shaft comprises exterior threads that threadably engage with interior threads of the first shaft;
wherein the exterior threads of the first shaft have a pitch that is greater than a pitch of the exterior threads of the second shaft.
4. The medical device of claim 3 , wherein:
the exterior threads of the first shaft form a right-handed helix; and
the exterior threads of the second shaft form a right-handed helix.
5. The medical device of claim 1 , wherein the fourth shaft is at least partially disposed within an elongate lumen of the third shaft.
6. The medical device of claim 1 , further comprising a handle that is coupled to the first shaft such that rotation of the handle results in rotation of the first shaft.
7. The medical device of claim 1 , further comprising:
a casing that is fixedly coupled to the second shaft and a proximal end of the third shaft; and
a shuttle that is rotatably, but not threadably, coupled to the first shaft, wherein the shuttle is disposed within the housing;
wherein rotation of the first shaft with respect to the housing results in axial displacement of the casing relative to the shuttle.
8. The medical device of claim 7 , wherein the housing comprises one or more recesses that interact with the casing to prevent rotation of the second shaft relative to the housing.
9. The medical device of claim 1 , wherein the housing comprises an adaptor that is configured to facilitate attachment of the housing to an introducer.
10. The medical device of claim 1 , wherein:
a proximal portion of the fourth shaft is longitudinally displaceable relative to the third shaft; and
the fourth shaft is attached to the third shaft at a position that is adjacent a distal end of the third shaft.
11. An osteotome comprising:
a housing;
a first shaft that is threadably coupled to the housing;
a second shaft that is threadably coupled to the first shaft;
a third shaft that is coupled to the first shaft such that axial displacement of the first shaft a first distance relative to the housing results in axial displacement of the third shaft a distance relative to the housing that is equal to the first distance;
a fourth shaft that is at least partially disposed within an elongate lumen of the third shaft, wherein the fourth shaft is coupled to the second shaft such that axial displacement of the second shaft a second distance relative to the housing results in axial displacement of the fourth shaft a distance relative to the housing that is equal to the second distance; and
a distal portion of the osteotome, the distal portion comprising both a portion of the third shaft and a portion of the fourth shaft;
wherein rotation of the first shaft relative to the housing simultaneously causes (1) axial displacement of the first shaft relative to the housing at a first rate, (2) axial displacement of the second shaft relative to the housing at a second rate that is different from the first rate, and (3) articulation of the distal portion such that a distal tip of the osteotome is laterally displaced relative to a longitudinal axis of the osteotome.
12. The osteotome of claim 11 , wherein rotation of the first shaft relative to the housing causes displacement of the distal portion in an axial direction relative to the housing.
13. The osteotome of claim 11 , wherein:
the first shaft comprises exterior threads that threadably engage with interior threads of the housing; and
the second shaft comprises exterior threads that threadably engage with interior threads of the first shaft;
wherein the exterior threads of the first shaft have a pitch that is greater than a pitch of the exterior threads of the second shaft.
14. A method of manipulating an osteotome, the method comprising:
obtaining the osteotome of claim 11 ;
inserting a distal portion of the osteotome into bone of a patient; and
rotating the first shaft of the osteotome relative to the housing.
15. The method of claim 14 , wherein inserting the distal portion of the osteotome into bone of the patient comprises inserting the distal portion of the osteotome through an introducer.
16. The method of claim 15 , further comprising coupling the housing to the introducer prior to rotating the first shaft of the osteotome relative to the housing.
17. The method of claim 14 , wherein the bone of the patient is a human vertebra.