Cable and roller bone saw
A surgical saw for use in cutting bone. The saw may include a cutting member that is rotated about a drive pulley, an idler pulley, and first and second guide members. The guide members are in contact with an outer perimeter surface of a bone to be cut. The guide members may be moveable in opposite directions relative to the outer perimeter surface. In turn, the cutting member may be engaged with the bone in response to the movement of the guide members. The guide members may move along the outer perimeter surface of the bone until the cutting member has been moved through an entire cross-section of a bone to separate the bone. The saw may be initially inserted in a bore created in the bone to dispose the idler pulley at an opposite side of the bone as the drive pulley when commencing the cutting operation.
1. A saw for cutting through a bone, comprising:
a drive pulley that is positionable at a first location relative to the bone;
an idler pulley that is positionable at a second location relative to the bone; and
a cutting member that is positionable to extends through a bore that extends at least partially through the bone, that the cutting member is rotatable relative to the drive pulley and the idler pulley to contact a sidewall of the bore through which the cutting member extends to cut the bone, wherein the cutting member extends at least partially through a first bore and at least partially through a second bore, and wherein the first bore and the second bore intersect.
2. The saw of claim 1 , further comprising:
a tensioner engaged with the cutting member to maintain tension on the cutting member.
3. The saw of claim 2 , wherein the tensioner is engaged with the drive pulley to impart the tension on the cutting member.
4. The saw of claim 1 , wherein the first bore and the second bore do not intersect.
5. A saw for cutting through a bone, comprising:
a drive pulley operatively engaged with a cutting member and positionable at a first side of the bone to be cut;
an idler pulley positionable at a second side of the bone that is opposite the first side, wherein the idler pulley is passed through a bore extending through the bone to be positioned at the second side, and wherein the cutting member is engaged with the idler pulley such that the cutting member extends through the bore between the drive pulley and the idler pulley;
a first guide assembly comprising:
a first guide pulley engaged with the cutting member between the idler pulley and the drive pulley, and
a first perimeter bearing contactingly engageable with an outer perimeter surface of the bone and adapted to maintain contacting engagement with the outer perimeter surface while moving in a first direction along the outer perimeter surface;
a second guide assembly comprising:
a second guide pulley engaged with the cutting member between the idler pulley and the drive pulley, and
a second perimeter bearing contactingly engageable with the outer perimeter surface and adapted to maintain contacting engagement with the outer perimeter surface while moving in a second direction opposite the first direction; and
a drive mechanism engaged with the drive pulley to cause movement of the cutting member around the drive pulley, first guide pulley, idler pulley, and second guide pulley, wherein the first guide assembly and the second guide assembly are moveable about the outer perimeter surface to contact the bone with the cutting member as the first guide assembly and the second guide assembly moves along the outer perimeter surface of the bone.
6. The saw of claim 5 , further comprising:
a tensioner engaged with the cutting member to maintain tension on the cutting member as the first guide assembly and the second guide assembly moves along the outer perimeter of the bone.
7. The saw of claim 6 , wherein the tensioner is engaged with the drive pulley to impart the tension on the cutting member.
8. The saw of claim 7 , wherein the bone comprises a cylindrical outer perimeter surface, and the first direction comprises a first circumferential direction and the second direction comprises a second circumferential direction.
9. The saw of claim 8 , further comprising:
a first biasing member acting on the first guide assembly to maintain the first perimeter bearing in contacting engagement with the outer perimeter surface as the first guide assembly moves along the outer perimeter surface in the first direction; and
a second biasing member acting on the second guide assembly to maintain the second perimeter bearing in contacting engagement with the outer perimeter surface as the second guide assembly moves along the outer surface perimeter in the second direction.
10. The saw of claim 9 , wherein the first guide assembly moves along the cylindrical outer perimeter from adjacent the drive pulley to adjacent the idler pulley in the first circumferential direction and the second guide assembly moves along the cylindrical outer perimeter from adjacent the drive pulley to adjacent the idler pulley in the second circumferential direction.
11. The saw of claim 10 , wherein the first perimeter bearing comprises at least one bearing surface and the second perimeter bearing comprises at least another bearing surface.
12. The saw of claim 11 , wherein the at least one bearing surface of each of the first perimeter bearing and the second perimeter bearing is offset in a direction corresponding to an axial direction of the cylindrical outer perimeter from the respective one of the first guide pulley or the second guide pulley such that the respective bearing surface maintains contacting engagement with the cylindrical outer perimeter adjacent to a portion of the bone cut by the cutting member.
13. The saw of claim 9 , wherein the first guide assembly is disposed at a distal end of a first support arm that is pivotally displaceable from a proximal end of the first support arm and the second guide assembly is disposed at a distal end of a second support arm that is pivotally displaceable from a proximal end of the second support arm.
14. The saw of claim 13 , wherein the first biasing member acts on the first support arm and the second biasing member acts on the second support arm to bias the first and second guide assemblies toward one other.
15. The saw of claim 14 , wherein action of respective ones of the first biasing member on the first support arm and the second biasing member on the second support arm results in at least a component force vector on the first and second guide assemblies in a radial direction relative to the cylindrical outer perimeter.
16. The saw of claim 15 , wherein the idler pulley and the drive pulley are mounted on a body member, which is located in the bore to dispose the drive pulley at the first side of the bone and the idler pulley at the second side of the bone.
17. The saw of claim 16 , wherein the proximal end of the first support arm and the proximal end of the second support arm are pivotally engaged with the body member.
18. The saw of claim 17 , wherein the proximal end of the first support arm and the proximal end of the second support arm are pivotal about a common axis of the drive pulley.
19. The saw of claim 18 , wherein the tensioner allows the drive pulley, the first support arm, and the second support arm to move relative to the idler pulley to maintain tension on the cutting member.
20. The saw of claim 19 , wherein the tensioner comprises a spring member between the drive pulley and the idler pulley.
21. The saw of claim 5 , wherein the bore comprises a drill hole created by drilling through the bone from the first side of the bone to the second side of the bone.