SYSTEMS FOR DISTRACTION OF UNCINATE JOINTS
A tool for distracting uncinate joints of a cervical spine segment includes two connector arms configured to access the cervical spine segment through soft tissue anterior to the cervical spine segment. The connector arms form respective receptacles for holding extensions coupled to respective distractor tips so as to position the distractor tips at distal ends of the connector arms and in the cervical spine segment. The tool further includes a control coupled to proximate ends of the connector arms and configured to adjust distance between the connector arms, at least at the distal ends, to distract the uncinate joints with the distractor tips. A system for distracting uncinate joints of a cervical spine segment includes a pair of distractor tips for insertion into the uncinate joints, respectively, along a medial-to-lateral direction from intervertebral disc space of the cervical spine segment, to distract the uncinate joints.
1 . A tool for distracting uncinate joints of a cervical spine segment, comprising:
two connector arms configured to access the cervical spine segment through soft tissue anterior to the cervical spine segment, the connector arms forming respective receptacles for holding extensions coupled to respective distractor tips so as to position the distractor tips at distal ends of the connector arms and in the cervical spine segment; and
a control coupled to proximate ends of the connector arms and configured to adjust distance between the connector arms, at least at the distal ends, to distract the uncinate joints with the distractor tips.
2 . The tool of claim 1 , each of the receptacles being a channel in a respective one of the connector arms.
3 . The tool of claim 2 , each of the receptacles cooperating with shape of the extensions to restrict rotation of the distractor tips about axis between the distal and proximate ends of the respective one of the connector arms.
4 . The tool of claim 2 , each of the receptacles cooperating with shape of the extensions to allow rotation of the distractor tips about axis between the distal and proximate ends of the respective one of the connector arms.
5 . The tool of claim 1 , each of the connector arms having width sufficient to retract the soft tissue, when the distal ends of the connector arms are positioned at the cervical spine segment.
6 . The tool of claim 5 , the width being at least one centimeter.
7 . The tool of claim 5 , the connector arms including retractor blades having the width sufficient to retract the soft tissue.
8 . The tool of claim 1 , further comprising, for each of the connector arms, a fastener for locking position of a respective one of the distractor tips relative to the connector arm.
9 . The tool of claim 1 , further comprising a dial indicating a measure of distance between the distractor tips.
10 . The tool of claim 1 , further comprising the distractor tips.
11 . The tool of claim 1 , further comprising retractor blades coupled to the connector arms for retraction of the soft tissue.
12 . A system for distracting uncinate joints of a cervical spine segment, comprising:
a pair of distractor tips for insertion into the uncinate joints, respectively, along a medial-to-lateral direction from intervertebral disc space of the cervical spine segment, to distract the uncinate joints, each of the distractor tips having a lateral side and a medial side respectively facing and facing away from a respective one of the uncinate joints during said insertion, height of each distractor tip gradually increasing from the lateral side at least partway toward the medial side to ease said insertion.
13 . The system of claim 12 , further comprising a pair of extensions coupled with the distractor tips, each of the extensions being configured for mounting in a respective receptacle of an actuator for adjusting distance between the distractor tips.
14 . The system of claim 13 , each extension being integrally formed with a respective one of the distractor tips.
15 . The system of claim 13 , each distractor tip and respective extension being removably coupled to each other such that the distractor tips may be disconnected from the extensions and left in the uncinate joints.
16 . The system of claim 13 , each extension including an elongated rod.
17 . The system of claim 12 , each of the distractor tips characterized by rotational symmetry about lengthwise axis of the distractor tip, the lengthwise axis being oriented along a predominantly anterior-to-posterior direction when the distractor tip is positioned in a respective one of the uncinate joints.
18 . The system of claim 12 , each of the distractor tips being larger in a first dimension orthogonal to a lengthwise axis of the distractor tip than in a second dimension orthogonal to both the first dimension and the lengthwise axis, the lengthwise axis being oriented along a predominantly anterior-to-posterior direction when the distractor tip is positioned in a respective one of the uncinate joints.
19 . The system of claim 12 , each of the distractor tips including a tapered portion that is (a) elongated along a lengthwise dimension and (b) configured for insertion into the uncinate joint from intervertebral disc space of the cervical spine segment with the lengthwise dimension oriented along a predominantly anterior-to-posterior direction, the tapered portion having height in a heightwise dimension orthogonal to the lengthwise dimension, the height having a gradient along a widthwise dimension orthogonal to the lengthwise dimension and the heightwise dimension to define tapering of the tapered portion to facilitate said insertion.
20 . The system of claim 19 , the tapered portion having taper angle in range between 5° and 60°.
21 . The system of claim 19 , the tapered portion having taper angle in range between 10° and 45°.
22 . The system of claim 19 , minimum height of the tapered portion being less than 2 millimeters.
23 . The system of claim 22 , maximum height of the tapered portion being between 4 and 10 millimeters.
24 . The system of claim 19 , the tapered portion having generally triangular cross section in plane orthogonal to the lengthwise dimension.
25 . The system of claim 24 , corner of the triangular cross section associated with leading edge of the tapered element, during said insertion, being blunt.
26 . The system of claim 19 , the distractor tips being disposable.
27 . The system of claim 19 , the distractor tips being composed of metal.
28 . The system of claim 19 , the distractor tips being composed of polymer.
29 . The system of claim 12 , the distractor tips being configured to be coupled to respective connector arms of an actuator for adjusting distance between the distractor tips by adjusting distance between the connector arms, the system further comprising a pair of retractor blades to be mounted on the connector arms, respectively, for retraction of soft tissue anterior to the cervical spine segment.
30 . The system of claim 29 , the retractor blades being disposable.
31 . The system of claim 29 , the retractor blades being composed of metal.
32 . The system of claim 29 , the retractor blades being composed of polymer.