In situ rod cutters
In accordance with at least one aspect of this disclosure, a surgical rod cutter assembly includes a first blade member including a first open notch in a first end thereof. The first open notch spans across a first ingress axis, along which a rod is inserted for cutting. A first rotation bore is defined through the first blade member, a linkage of the first blade member extends away from the rotation bore on a first linkage axis, and the first rotation bore intersects the first linkage axis.
1 . A surgical rod cutter assembly comprising:
a first blade member including a first open notch in a first end thereof, wherein the first open notch spans across a first ingress axis, wherein there is a first rotation bore defined through the first blade member, wherein a linkage of the first blade member extends away from the rotation bore on a longitudinal axis of the first linkage, and wherein the first rotation bore intersects the longitudinal axis of the first linkage;
a second blade member including a second open notch in a first end thereof, wherein the second open notch spans across a second ingress axis, wherein there is a second rotation bore defined through the second blade member, wherein a linkage of the second blade member extends away from the second rotation bore on a longitudinal axis of the second linkage, and wherein the second rotation bore intersects the longitudinal axis of the second linkage; and
a fulcrum pin engaged through the first and second rotation bores to rotationally engage the first and second blade members together wherein:
in an open position, the first and second ingress axes are aligned with one another to admit a rod therealong into the first and second open notches for cutting, and the first and second linkage axes are angled to a narrow position relative to one another and wherein:
in a closed position, the first and second ingress axes are angled relative to one another, and, the first and second linkage axes are angled at a widened position relative to the narrow position,
wherein the first blade member includes a first pawl extending into a pocket of the second blade member, wherein in the closed position, the first pawl cooperates with the terminal surface of the second open notch to form a capture pocket configured to capture a cut rod piece after cutting the rod.
2 . The assembly as recited in claim 1 , wherein in both the open position and in the closed position, the first and second ingress axes both pass through a rotation axis that extends along the fulcrum pin.
3 . The assembly as recited in claim 1 , wherein the first open notch includes:
a first notch surface on one side of the first ingress axis;
a second notch surface opposite the first notch surface across the first ingress axis, and
a terminal surface connecting between the first and second notch surfaces, terminating the first open notch along the first ingress axis,
wherein the first open notch defines an opening between the first and second notch surfaces that opens away from the fulcrum pin.
4 . The assembly as recited in claim 3 , wherein the first and second notch surfaces of the first open notch are parallel to one another, and wherein the terminal surface of the first open notch is semi-cylindrical.
5 . The assembly as recited in claim 3 , wherein the second open notch includes:
a first notch surface on one side of the second ingress axis;
a second notch surface opposite the first notch surface across the second ingress axis; and
a terminal surface connecting between the first and second notch surfaces, terminating the second open notch along the second ingress axis,
wherein the second open notch defines an opening between the first and second notch surfaces that opens away from the fulcrum pin.
6 . The assembly as recited in claim 5 , wherein the first and second notch surfaces of the second open notch are parallel to one another, and wherein the terminal surface of the second open notch is semi-cylindrical.
7 . The assembly as recited in claim 5 , wherein in the open position, the first notch surface of the first open notch is aligned parallel with the first notch surface of the second open notch, and the second notch surface of the first open notch is aligned parallel with the second notch surface of the second open notch.
8 . The assembly as recited in claim 1 , wherein in the closed position, the first and second ingress axes are angled obliquely relative to one another.
9 . The assembly as recited in claim 8 , wherein in the closed position, the first and second open notches are misaligned for holding a cut rod piece.
10 . The assembly as recited in claim 1 , wherein the second blade member includes a second pawl extending into a pocket of the first blade member, wherein in the closed position, the second pawl cooperates with the terminal surface of the first open notch to form a capture pocket configured to capture a cut rod piece after cutting a rod.
11 . The assembly as recited in claim 10 , further comprising and actuator tool having:
a first linkage including a first handle portion, a first main pin bore, and a first linkage bore; and
a second linkage including a second handle portion, a second main pin bore, and a second linkage bore,
wherein the first and second linkages are joined to one another by a main pin engaged through the first and second main pin bores for relative rotation,
wherein the first linkage is pinned with a first linkage pin that passes through the first linkage bore and a corresponding bore of the first blade member, and
wherein the second linkage is pinned with a second linkage pin that passes through the second linkage bore and a corresponding bore of the second blade member.
12 . The assembly as recited in claim 11 , wherein the first linkage pin is removably engaged to the first linkage and to the first blade member with a movable detent ball in the first linkage pin, and wherein the second linkage pin is removably engaged to the second linkage and to the second blade member with a movable detent ball in the second linkage pin.
13 . The assembly as recited in claim 11 , further comprising a threaded rod connecting the first handle portion to the second handle portion, wherein a knob is operatively connected to the threaded rod to actuate the first and second linkages between the first and second positions.
14 . The assembly as recited in claim 13 , wherein the knob includes leveraging bores configured to receive a lever arm to facilitate rotation of the knob.
15 . The assembly as recited in claim 1 , further comprising a bearing washer extending around the fulcrum pin and rotatably engaged to inward facing bearing surfaces of each of the first and second blade members.
16 . The assembly as recited in claim 15 , further comprising:
a first outside washer engaged to the fulcrum pin and an outer surface of the first blade member; and
a second outside washer engaged to the fulcrum pin and an outer surface of the second blade member.
17 . A kit comprising:
a package having a sterile interior enclosing:
a first blade member including a first open notch in a first end thereof, wherein the first open notch spans across a first ingress axis, wherein there is a first rotation bore defined through the first blade member, wherein a linkage of the first blade member extends away from the rotation bore on a longitudinal axis of the first linkage, and wherein the first rotation bore intersects the longitudinal axis of the first linkage;
a second blade member including a second open notch in a first end thereof, wherein the second open notch spans across a second ingress axis, wherein there is a second rotation bore defined through the second blade member, wherein a linkage of the second blade member extends away from the second rotation bore on a longitudinal axis of the second linkage, and wherein the second rotation bore intersects the longitudinal axis of the second linkage; and
a fulcrum pin configured to be engaged through the first and second rotation bores to rotationally engage the first and second blade members together wherein:
in an open position, the first and second ingress axes are aligned with one another to admit a rod therealong into the first and second open notches for cutting, wherein the first and second linkage axes are angled to a narrow position relative to one another in the open position, and wherein:
in a closed position, the first and second ingress axes are angled relative to one another, and wherein in the closed position, the first and second linkage axes are angled at a widened position relative to the narrow position,
wherein the first blade member includes a first pawl extending into a pocket of the second blade member, wherein in the closed position, the first pawl cooperates with the terminal surface of the second open notch to form a capture pocket configured to capture a cut rod piece after cutting the rod.
18 . The kit as recited in claim 17 , further comprising a pair of ball detent pins in the package, configured to join the first and second blade members to an actuator tool.
19 . The kit as recited in claim 18 , further comprising the actuator tool in the package.
20 . The kit as recited in claim 19 , further comprising a leveraging member in the package configured to engage a threaded rod knob of the actuator tool to provide leverage for actuating the first and second blade members.