Methods and systems for characterizing intervertebral disc space
A system and method for determining at least one parameter of an intervertebral space. The system and method may be useful to determine the appropriate size and geometry of a spinal implant. An expandable member may be inserted into an intervertebral disc space and inflated with an imaging contrast medium. The inflated expandable member and at least the intervertebral disc space may be imaged. The volume of imaging contrast medium in the expandable member may be measured in order to determine the volume of the disc space.
1 . A method for determining at least one parameter of an intervertebral disc space, comprising:
inserting an expandable member into an at least partially evacuated intervertebral disc space;
inflating the expandable member with an imaging contrast medium;
imaging at least the intervertebral disc space when the expandable member has sufficiently occupied the at least partially evacuated disc space; and
measuring the volume of imaging contrast medium in the expandable member thereby determining at least one parameter of the intervertebral disc space.
2 . The method of claim 1 , wherein measuring the volume of imaging contrast medium comprises measuring the volume of imaging contrast medium as it is delivered to the expandable member.
3 . The method of claim 1 , further comprising deflating the expandable member, and where measuring the volume of imaging contrast medium comprises measuring the volume of imaging contrast medium removed from the expandable member during deflation of the expandable member.
4 . The method of claim 1 , wherein imaging the expandable member comprises an imaging procedure selected from the group consisting of X-ray, C-arm fluoroscopy, CT scan, MRI, and PET scans.
5 . The method of claim 1 , wherein the parameter is a dimension selected from the group consisting of the height, posterior-anterior width, and lateral width of the intervertebral disc space.
6 . The method of claim 1 , wherein the parameter is a two-dimensional parameter selected from the footprint area and projected area of the intervertebral disc space.
7 . The method of claim 1 , wherein the parameter is a three-dimensional parameter selected from the geometry and volume of the intervertebral disc space.
8 . The method of claim 1 , further comprising determining a characteristic of the intervertebral disc space selected from the group consisting of the concave or convex nature of the vertebral end plates, the location of the endplate/nucleus boundary, the location of the annulus/nucleus boundary, and the shape of the intervertebral disc space.
9 . The method of claim 1 , wherein inserting an expandable member and inflating the expandable member are carried out using minimally invasive surgical techniques.
10 . The method of claim 1 , wherein the expandable member is a balloon.
11 . The method of claim 1 , wherein the imaging contrast medium is selected from the group consisting of X-ray, C-arm fluoroscopy, CT scan, MRI, and PET scan imaging contrast media.
12 . The method of claim 1 , further comprising monitoring the pressure of the imaging contrast medium during inflation of the expandable member and stopping inflation when the pressure reaches a predetermined set point.
13 . A method for determining at least one parameter of an intervertebral disc space, comprising:
removing at least a portion of a nucleus of the intervertebral disc;
inserting an expandable member into the disc space;
inflating the expandable member with an imaging contrast medium;
measuring the volume of imaging contrast medium used to inflate the expandable member;
imaging the intervertebral disc space while the expandable member is inflated with the imaging contrast medium to determine when the expandable member has sufficiently occupied the disc space; and
calculating the volume of imaging contrast medium in the expandable member to determine the at least one parameter.
14 . The method of claim 13 , wherein removing at least a portion of the nucleus of the intervertebral disc space, inserting an expandable member, and inflating the expandable member are carried out using minimally invasive surgical techniques.
15 . The method of claim 13 , wherein the expandable member is a balloon.
16 . The method of claim 13 , further comprising monitoring the pressure of the imaging contrast medium during inflation and stopping inflation when the pressure reaches a predetermined set point.
17 . The method of claim 13 , wherein the imaging contrast medium is selected from the group consisting of X-ray, C-arm fluoroscopy, CT scan, MRI, and PET scan imaging contrast media.
18 . The method of claim 13 , wherein measuring the volume of imaging contrast medium comprises measuring the volume of imaging contrast medium as it is delivered to the expandable member.
19 . The method of claim 13 , further comprising deflating the expandable member, and wherein measuring the volume of imaging contrast medium comprises measuring the volume of imaging contrast medium removed from the expandable member during deflation of the expandable member.
20 . The method of claim 13 , wherein imaging the expandable member comprises an imaging procedure selected from the group consisting of an X-ray, C-arm fluoroscopy, CT scan, MRI, and PET scan.
21 . The method of claim 13 , wherein the parameter is a dimension selected from the group consisting of the height, posterior-anterior width, and lateral width of the intervertebral disc space.
22 . The method of claim 13 , wherein the parameter is a two-dimensional parameter selected from the footprint area and projected area of the intervertebral disc space.
23 . The method of claim 13 , wherein the parameter is a three-dimensional parameter selected from the geometry and volume of the intervertebral disc space.
24 . The method of claim 13 , further comprising determining a characteristic of the intervertebral disc space selected from the group consisting of the concave or convex nature of the vertebral end plates, the location of the endplate/nucleus boundary, the location of the annulus/nucleus boundary, and the shape of the intervertebral disc space.
25 . An intradisc sizer, comprising:
a longitudinal element comprising distal and proximate ends;
an expandable member comprising an internal cavity connected to and in fluid communication with the distal end of the longitudinal element;
a dispensing device adapted to be connected to the proximate end of the longitudinal element; and
an imaging contrast medium positionable within the dispensing device.
26 . The device of claim 25 , wherein the imaging contrast medium is selected from the group consisting of X-ray, C-arm fluoroscopy, CT scan, MRI, and PET scan imaging contrast media.
27 . The device of claim 25 , wherein the expandable member is an unconstrained balloon.
28 . The device of claim 25 , wherein the expandable member comprises a polymeric material selected from the group consisting of polyethylene terephthalates, polyolefins, polyurethanes, nylon, polyvinyl chloride, silicone, polyetherketone, polylactide, polyglycolide, poly(lactide-co-glycolide), poly(dioxanone), poly([epsilon]-caprolactone), poly(hydroxylbutyrate), poly(hydroxylvaierate), tyrosine-based polycarbonate, polypropylene fumarate, and mixtures and combinations thereof.
29 . The device of claim 25 , wherein the dispensing device is a syringe graduated by volume.
30 . The device of claim 25 , further comprising a pressure measurement device connected to and in communication with the proximate end of the longitudinal element.
31 . The device of claim 25 , further comprising a guidewire positioned within the longitudinal element.
32 . The device of claim 25 , further comprising a guide cannula or catheter, wherein the longitudinal element and expandable member is capable of being positioned within the guide cannula or catheter.
33 . The device of claim 25 , wherein the longitudinal element is capable of being selectively pivoted between a linear and curved configuration.
34 . A kit comprising:
a longitudinal element comprising distal and proximate ends;
an expandable member connected to and in fluid communication with the distal end of the longitudinal element;
a dispensing device adapted to be connected to the proximate end of the longitudinal element; and
an imaging contrast medium.
35 . The kit of claim 34 , wherein the imaging contrast medium is selected from the group consisting of X-ray, C-arm fluoroscopy, CT scan, MRI, and PET scan imaging contrast media.
36 . The kit of claim 34 , wherein the expandable member is an unconstrained balloon.
37 . The kit of claim 34 , wherein the expandable member comprises a polymeric material selected from the group consisting of polyethylene terephthalates, polyolefins, polyurethanes, nylon, polyvinyl chloride, silicone, polyetherketone, polylactide, polyglycolide, poly(lactide-co-glycolide), poly(dioxanone), poly([epsilon]-caprolactone), poly(hydroxylbutyrate), poly(hydroxylvalerate), tyrosine-based polycarbonate, polypropylene fumarate, and mixtures and combinations thereof.
38 . The kit of claim 34 , wherein the dispensing device is a syringe graduated by volume.
39 . The kit of claim 34 , further comprising a pressure measurement device that is detachably connectible to the proximate end of the longitudinal element.
40 . The kit of claim 34 , further comprising a guidewire capable of being positioned within the longitudinal element.
41 . The kit of claim 34 , further comprising a guide cannula or catheter, wherein the longitudinal element and expandable member is capable of being positioned within the guide cannula or catheter.