Surgical cable tensioning apparatus and method
View Patent ↗A cable tensioning apparatus and method are provided for positioning and tensioning a surgical cable to skeletal tissue or to implants. The invention is most applicable for securing surgical cable and/or orthopedic implants to bone in orthopedic surgery. A linearly translated drive rod attached to cable is driven by a friction drive to create tension on the surgical cable.
1. A cable tensioning apparatus for generating tension in a cable, the cable tensioning apparatus comprising:
an elongate shaft assembly having proximal and distal ends and a longitudinal axis extending therebetween;
a proximal cable guide device mounted to the elongate shaft assembly;
a distal cable guide device mounted to the elongate shaft assembly, longitudinally spaced from the proximal cable guide device;
cable guideways of the proximal and distal cable guide devices that are aligned with and longitudinally spaced from each other and spaced from the elongate shaft assembly for receiving the cable therethrough, the distal cable guide device including a bridge portion extending above the shaft assembly for spacing the distal cable guideway from the shaft assembly;
a clamping mechanism of the proximal cable guide device for clamping the cable relative to the proximal cable guide device;
a plurality of detachable clamp mechanisms for connecting to an upper end portion of the bridge portion of the distal cable guide device to clamp the cable extending through the cable guideway,
a detachable connection between the upper end portion of the bridge portion of the distal cable guide device and each of the plurality of clamp mechanisms so that with one of the plurality of clamp mechanisms attached to the bridge portion the clamp mechanism can be clamped on the cable and detached from the bridge portion to maintain tension in the cable so that another of the plurality of clamp mechanisms can be attached to the upper end portion of the bridge portion for tensioning another cable; and
a drive mechanism housed in the shaft assembly and operable to shift the proximal cable guide device longitudinally in a proximal direction away from the shaft assembly distal end so that with the cable extending through the cable guideways and clamped to the proximal cable guide device, the longitudinally spaced proximal and distal cable guide devices allow an operator to observe tension develop in a length of cable exposed between the longitudinally spaced cable guide devices and spaced from the shaft assembly as the proximal cable guide device is shifted longitudinally in the proximal direction.
2. The cable tensioning apparatus of claim 1 , wherein the shaft assembly includes a housing portion to which the distal cable guide device is mounted and a drive rod slidably connected to the housing portion to which the proximal cable guide device is mounted so that operation of the drive mechanism causes the drive rod to slide longitudinally in the proximal direction relative to the housing portion to shift the proximal cable guide device away from the distal cable guide device to generate tension in the cable.
3. The cable tensioning apparatus of claim 1 , wherein the cable guideways each include a longitudinal throughbore each being longitudinally shorter than the longitudinal spacing between the cable guideways to allow for access for cleaning inner surfaces thereof.
4. The cable tensioning apparatus of claim 1 , wherein the drive mechanism includes a lever actuator extending below the shaft assembly and pivotally connected thereto so that pivoting the lever operates the drive mechanism, and the cable guideways are spaced above the shaft assembly so that the length of cable exposed between the proximal and distal cable guide devices does not interfere with movement of the lever actuator.
5. The cable tensioning apparatus of claim 4 , wherein the pivot connection between the lever actuator and the shaft assembly is positioned at an upper portion of the shaft assembly and below the cable guideways to optimize the mechanical advantage for pivoting the lever actuator without interfering with the exposed length of cable.
6. The cable tensioning apparatus of claim 1 , wherein the drive mechanism includes a lever actuator, and
a handle that depends from the shaft assembly configured to allow a user to shift the lever actuator toward the handle for operating the drive mechanism without grasping the shaft assembly.
7. The cable tensioning apparatus of claim 1 , further comprising a releasable stop configured to allow the proximal cable guide device to shift in the proximal direction and to restrict the proximal cable guide device from shifting in the distal direction to maintain tension in the length of cable during tensioning thereof, and
a release lever of the releasable stop pivotally connected to the shaft assembly and extending therebelow for being pivoted to release the releasable stop so that the proximal cable guide device can shift toward the distal cable guide device to reduce the tension in the length of cable.
8. The cable tensioning apparatus of claim 1 , wherein the shaft assembly has a tension indicating mechanism including a proximal portion and a distal portion that is slidable relative to the proximal portion along the longitudinal axis and a resilient member mounted therebetween to bias the distal portion longitudinally away from the proximal portion so that shifting the proximal cable guide device in the proximal direction to develop tension in the cable causes the distal portion to shift in the proximal direction against the bias of the resilient member by a distance corresponding to the tension in the cable, and
an indicator on one of the distal portion and the proximal portion to indicate the amount of tension in the cable.