Rotary angled scraper for spinal disc space preparation
A scraper instrument for preparing an intervertebral disc space is disclosed. The scraper instrument incorporates a uniquely configured end bit having a cutting head with a cavity for passing debris therethrough. Variations of the scraper instrument include one or more angled portions and shaft assemblies that transmit rotational torque applied at the proximal end of the instrument through the at least one angled portion and to the distally located end bit. An adjustable angled portion in addition to a bayonet-like angled portion is disclosed.
1 . A scraper instrument, comprising:
a shaft assembly having at least one angled portion comprising:
a outer shaft with a central bore extending from a proximal end to a distal end;
an inner shaft disposed inside the central bore of the outer shaft such that the inner shaft is permitted to rotate with respect to the outer shaft; the inner shaft having a proximal end and a distal end;
a flexible shaft having a proximal end and a distal end; the proximal end of the flexible shaft connected to the distal end of the inner shaft wherein the flexible shaft is located at the angled portion;
an end bit having a proximal end and a distal end; the proximal end of the end bit connected to the distal end of the flexible shaft; the end bit having a cutting head at the distal end; the cutting head having at least one cutting surface; and
wherein rotational torque applied to the proximal end of the inner shaft is transmitted to the flexible shaft at the angled portion and to the end bit to rotate the cutting head.
2 . The scraper instrument of claim 1 wherein the cutting head includes a top surface and a bottom surface interconnected by two sidewalls, forming four cutting surfaces; wherein first and fourth cutting surfaces are interconnected by a first sidewall and second and third cutting surfaces are interconnected by a second sidewall.
3 . The scraper instrument of claim 2 wherein at least one of the sidewalls is curved outwardly for a substantially convex outer profile.
4 . The scraper instrument of claim 2 wherein at least one of the sidewalls is curved inwardly for a substantially concave outer profile.
5 . The scraper instrument of claim 2 wherein at least one of the cutting surfaces are angled with respect to the top surface.
6 . The scraper instrument of claim 2 wherein at least one of the cutting surfaces are substantially perpendicular to the top surface.
7 . The scraper instrument of claim 2 wherein at least one of the four cutting surfaces is not diametric.
8 . The scraper instrument of claim 2 further including a cavity extending from the top surface to the bottom surface.
9 . The scraper instrument of claim 1 wherein the at least one angled portion defines two parallel axes offset from each other to form a bayonet-like configuration for the instrument.
10 . The scraper instrument of claim 1 wherein the angle of the at least one angled portion is adjustable.
11 . The scraper instrument of claim 1 further including a coupler having a proximal end and a distal end; the coupler being connected between the inner shaft and the end bit.
12 . A scraper instrument, comprising p 1 a rotatable inner shaft;
a rotatable end bit having a cutting head; the end bit being connected to the inner shaft; and
an outer shaft connected to the inner shaft such that the inner shaft is permitted to move relative to the outer shaft.
13 . The scraper instrument of claim 12 wherein the cutting head includes a top surface and a bottom surface interconnected by two sidewalls, forming four cutting surfaces; wherein first and fourth cutting surfaces are interconnected by a first sidewall and second and third cutting surfaces are interconnected by a second sidewall.
14 . The scraper instrument of claim 13 wherein at least one of the sidewalls is curved.
15 . The scraper instrument of claim 13 wherein at least one of the cutting surfaces is angled with respect to the top surface.
16 . The scraper instrument of claim 13 wherein at least one of the cutting surfaces are substantially perpendicular to the top surface.
17 . A scraper instrument of claim 12 wherein the end bit is extendable and retractable with respect to the distal end of the outer shaft.
18 . A scraper instrument of claim 12 further including at least one angled portion and a flexible shaft; the flexible shaft being interconnected between the inner shaft and the end bit and configured to transmit rotational torque that is applied to the proximal end of the inner shaft through the angled portion.
19 . The scraper instrument of claim 18 wherein the at least one angled portion is proximate to the distal end of the instrument.
20 . The scraper instrument of claim 18 wherein the at least one angled portion is located between the proximal end and distal end of the outer shaft with a first portion defining a first axis located between the proximal end and the angled portion and a second portion defining a second axis located between the angled portion and the distal end.
21 . The scraper instrument of claim 20 wherein the at least one angled portion is located along the instrument such that it is resident at or above the surface of the patient while in use and inserted into the patient.
22 . The scraper instrument of claim 20 wherein the first axis is substantially parallel and offset from the second axis.
23 . The scraper instrument of claim 22 wherein the first axis is offset from the second axis by at least half of the width of the first or second portion.
24 . The scraper instrument of claim 21 further including a second angled portion proximate the distal end.
25 . The scraper instrument of claim 21 wherein the angle of the at least one angled portion is adjustable.
26 . A method comprising:
providing a scraper instrument having a rotatable end bit with at least one cutting surface;
creating an working channel to the disc space of a patient;
inserting the scraper instrument through the working channel to the disc space in a posterolateral approach that is in the range of an angle of approximately 0 to 90 degrees to an anterior-posterior axis of a patient's spine;
rotating the end bit to remove tissue in the disc space;
changing the angle of the instrument to pass the end bit over substantially the entire area of a vertebral endplate.
27 . The method of claim 26 further including the step of extending or retracting the end bit from the distal end of the instrument.
28 . The method of claim 26 wherein the step of providing a scraper instrument further includes providing a scraper instrument that has at least one angled portion.
29 . The method of claim 26 wherein the step of inserting the scraper instrument includes inserting the scraper instrument in a posterolateral approach that is in the range of an angle of approximately 35-90 degrees to the anterior-posterior axis.