SURGICAL INSTRUMENTS WITH ARTICULATING SHAFTS
Various embodiments described herein are directed to curved ultrasonic blades. For example, a curved ultrasonic blade may comprise a proximally positioned straight section and a distally positioned curved section. The curved ultrasonic blade may be positioned within a shaft extending along a longitudinal axis. The curved ultrasonic blade may be translatable relative to the shaft. The curved section of the curved ultrasonic blade may translate from a first position where the curved section is at least partially contained within the shaft to a second position where the curved section curves away from the longitudinal axis. The curved section may define a radius of curvature that increases as the curved section curves away from the longitudinal axis. In another example, the curved ultrasonic blade may comprise a proximally positioned first curved section and a distally positioned second curved section. The curvature of the first curved section may be opposite of the curvature of the second curved section.
1 . A surgical instrument comprising:
a shaft extending along a longitudinal axis;
an ultrasonic blade positioned within the shaft, wherein the ultrasonic blade comprises a proximally positioned straight section and a distally positioned curved section;
wherein the ultrasonic blade is translatable along the longitudinal axis relative to the shaft from a first position where the curved section of the blade extends from a distal end of the shaft to a second position where the curved section of the blade is at least partially contained within the shaft.
2 . The surgical instrument of claim 1 , wherein the curved section of the ultrasonic blade defines a first radius of curvature when extended from the distal end of the shaft and a second radius of curvature when at least partially contained within the shaft, wherein the first radius of curvature is smaller than the second radius of curvature.
3 . The surgical instrument of claim 2 , wherein the curved section of the ultrasonic blade contacts an inner wall of the shaft when the curved section is at least partially contained within the shaft.
4 . The surgical instrument of claim 1 , wherein the curved section defines a radius of curvature, wherein the curved section subtends a first angle, and wherein a point of interface between the curved section and the straight section is at a position selected from the group consisting of a node of the ultrasonic blade and an anti-node of the ultrasonic blade.
5 . The surgical instrument of claim 4 , wherein the radius of curvature of the blade is described by:
radius
of
curvature
=
nc
π
4
θ
f
0
(
π
-
θ
2
)
0.5
;
wherein:
f 0 is a resonant frequency of the ultrasonic blade;
θ is the first angle;
n is a number of quarter wavelengths in the curved section; and
c is a phase velocity of ultrasonic vibrations in the ultrasonic blade at the resonant frequency.
6 . The surgical instrument of claim 4 , wherein the curved section of the ultrasonic blade comprises two quarter wavelengths at a resonant frequency of the ultrasonic blade.
7 . The surgical instrument of claim 4 , wherein a length of the curved section of the ultrasonic blade is greater than a distance between adjacent nodes on the straight section of the ultrasonic blade.
8 . The surgical instrument of claim 1 , wherein the shaft is fixed and the ultrasonic blade is translatable along the longitudinal axis relative to the shaft.
9 . The surgical instrument of claim 1 , wherein the ultrasonic blade is fixed and the shaft is translatable along the longitudinal axis relative to the ultrasonic blade.
10 . An ultrasonic blade comprising:
a proximally positioned straight section;
a distally positioned curved section;
wherein the ultrasonic blade is translatable along the longitudinal axis relative to a shaft from a first position where the curved section extends from a distal end of the shaft to a second position wherein the curved section is at least partially contained within the shaft;
wherein the shaft extends along a longitudinal axis.
11 . The ultrasonic blade of claim 10 , wherein the curved section defines a first radius of curvature when extended from the distal end of the shaft and a second radius of curvature when at least partially contained within the shaft, wherein the first radius of curvature is smaller than the second radius of curvature.
12 . The ultrasonic blade of claim 10 , wherein the curved section of the ultrasonic blade contacts an inner wall of the shaft when the curved section is at least partially contained within the shaft.
13 . The ultrasonic blade of claim 10 , wherein the curved section defines a radius of curvature, wherein the curved section subtends a first angle, and wherein a node or anti-node of the ultrasonic blade is positioned at a point of interface between the curved section and the straight section to guide a vibration modes of the ultrasonic blade substantially along the longitudinal axis.
14 . The ultrasonic blade of claim 10 , wherein the radius of curvature of the blade is described by:
radius
of
curvature
=
nc
π
4
θ
f
0
(
π
-
θ
2
)
0.5
;
wherein:
f 0 is a resonant frequency of the ultrasonic blade;
θ is the first angle;
n is a number of quarter wavelengths in the curved section; and
c is a phase velocity of ultrasonic vibrations in the ultrasonic blade at the resonant frequency.
15 . The ultrasonic blade of claim 10 , wherein the shaft is fixed and the ultrasonic blade is translatable along the longitudinal axis relative to the shaft.
16 . The ultrasonic blade of claim 10 , wherein the ultrasonic blade is fixed and the shaft is translatable along the longitudinal axis relative to the ultrasonic blade.
17 . A curved ultrasonic blade comprising:
a proximally positioned first curved section, wherein the first curved section is contained within a shaft extending along a longitudinal axis;
a distally positioned second curved section, wherein the second curved section is translatable from a first position where the second curved section is contained within the shaft to a second position where at least a portion of the second curved section extends from a distal end of the shaft.
18 . The curved ultrasonic blade of claim 17 , wherein the first curved section contacts an inner wall of the shaft when the curved section is contained within the shaft, wherein the second curved section defines a radius of curvature, wherein the translation from the first position to the second position corresponds to an increase in the radius of curvature.
19 . The curved ultrasonic blade of claim 17 , wherein the first curved section defines a first radius of curvature extending in a first direction, wherein the second curved section defines a second radius of curvature extending in an opposite second direction.
20 . The curved ultrasonic blade of claim 19 , wherein a node or anti-node of the curved ultrasonic blade is positioned at a point of interface between the first curved section and the second curved section to guide a vibration modes of the ultrasonic blade substantially along the longitudinal axis.