U.S. patent application number 10/137470 was filed with the patent office on 2003-10-30 for device and method for ultrasonic tissue excision with tissue selectivity.
Invention is credited to Manna, Ronald R., Novak, Theodore A. D., Sladek-Maharg, Werner, Voic, Dan.
Application Number | 20030204199 10/137470 |
Document ID | / |
Family ID | 29249737 |
Filed Date | 2003-10-30 |
United States Patent
Application |
20030204199 |
Kind Code |
A1 |
Novak, Theodore A. D. ; et
al. |
October 30, 2003 |
Device and method for ultrasonic tissue excision with tissue
selectivity
Abstract
A surgical method utilizes a cutting blade having a thickness
along a cutting edge of between about 0.0005 inch and about 0.020
inch and preferably between about 0.001 inch and 0.010 inch. The
blade is moved in contact with relatively hardly tissues which are
disposed adjacent to softer tissues at a surgical site in a
patient. The blade is ultrasonically vibrated during the moving of
the blade, whereby the hard tissue is cut with a modicum of damage
being inflicted on the soft tissue.
Inventors: |
Novak, Theodore A. D.; (King
Park, NY) ; Sladek-Maharg, Werner; (Coram, NY)
; Voic, Dan; (Clifton, NJ) ; Manna, Ronald R.;
( Valley Stream, NY) |
Correspondence
Address: |
R. Neil Sudol
COLEMAN SUDOL SAPONE, P.C.
714 Colorado Avenue
Bridgeport
CT
06605-1601
US
|
Family ID: |
29249737 |
Appl. No.: |
10/137470 |
Filed: |
April 30, 2002 |
Current U.S.
Class: |
606/169 |
Current CPC
Class: |
A61B 2017/320077
20170801; A61B 2017/320082 20170801; A61B 2018/00011 20130101; A61B
17/320068 20130101; A61B 2017/320044 20130101 |
Class at
Publication: |
606/169 |
International
Class: |
A61B 017/32 |
Claims
What is claimed is:
1. An ultrasonic surgical blade comprising a generally flat blade
having a thickness along a cutting edge of between about 0.0005
inch and about 0.020 inch.
2. The surgical blade defined in claim 1 wherein said thickness is
an edge thickness, said blade having a flat body portion with a
body thickness greater than said edge thickness, said blade
including a beveled or tapered region extending from said body
portion to said edge.
3. The surgical blade defined in claim 2 wherein said cutting edge
is disposed in a single plane and has an arcuate section.
4. The surgical blade defined in claim 3 wherein said cutting edge
includes a pair of straight sections continuous with said arcuate
section at opposite ends thereof.
5. The surgical blade defined in claim 4 wherein said blade is
provided with a shank having an axially extending bore for the
conveyance of cooling fluid to said cutting edge, said blade body
being provided with an axially extending through-slot communicating
at one end with said bore.
6. The surgical blade defined in claim 1 wherein the thickness of
said cutting edge is between about 0.001 inch and about 0.010
inch.
7. The surgical blade defined in claim 6 wherein the thickness of
said cutting edge is between about 0.001 inch and about 0.003
inch.
8. A surgical method comprising: providing a cutting blade having a
thickness along a cutting edge of between about 0.0005 inch and
about 0.020 inch; moving said blade in contact with relatively hard
tissue located adjacent to relatively soft tissue at a surgical
site in a patient, so that said cutting edge cuts through said hard
tissue and leaves said soft tissue substantially intact and
undamaged; and ultrasonically vibrating said blade during the
moving of said blade.
9. The method defined in claim 8 wherein the vibrating of said
blade is initiated prior to a contacting of said surgical site with
said blade and is maintained during an initial contact of said
blade with the tissues at said surgical site and during the moving
of said blade through said hard tissue.
10. The method defined in claim 9 wherein said blade is moved in a
continuous and uninterrupted stroke along said interface, the
ultrasonic vibrating of said blade being performed continuously and
uninterruptedly during said stroke.
11. The method defined in claim 3, further comprising terminating
the ultrasonic vibrating of said blade and removing said blade from
the surgical site upon the completion of said stroke.
12. The method defined in claim 4, further comprising introducing
irrigation fluid to said surgical site during the moving of said
blade along said interface.
13. The method defined in claim 8 wherein said blade is moved in a
continuous and uninterrupted stroke along an interface between said
hard tissue and said soft tissue, the ultrasonic vibrating of said
blade being performed continuously and uninterruptedly during said
stroke.
14. The method defined in claim 13, further comprising terminating
the ultrasonic vibrating of said blade and removing said blade from
the surgical site after the moving of said blade along said
interface.
15. The method defined in claim 8, further comprising introducing
irrigation fluid to said surgical site during the moving of said
blade.
16. The method defined in claim 8 wherein the thickness of said
cutting edge is between about 0.001 inch and about 0.010 inch.
17. A surgical method comprising: providing a cutting blade having
a thickness along a cutting edge of between about 0.001 inch and
about 0.010 inch; moving said blade in a surgical site in a patient
so that said cutting edge moves generally along an interface
between relatively hard tissue and relatively soft tissue; and
ultrasonically vibrating said blade during the moving of said blade
along said interface, whereby said hard tissue is cut and separated
from said soft tissue with a modicum of damage being inflicted on
said soft tissue.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a surgical method. More
particularly, this invention relates to a method for selectively
excising tissue during a surgical procedure. This invention also
pertains to an ultrasonic surgical blade utilizable in performing
the method.
[0002] Over the past 30 years, several ultrasonic tools have been
invented which can be used to ablate or cut tissue in surgery.
Wuchinich et al. in U.S. Pat. No. 4,223,676 and Idemoto et al in
U.S. Pat. No. 5,188,102 disclose such devices.
[0003] Ultrasonic surgical devices generally fall into two
categories. One is a blunt tip hollow probe that vibrates at
frequencies between 20 kc and 100 kc, with amplitudes up to 300
microns or more. Such devices ablate tissue by either producing
cavitation bubbles which implode and disrupt cells, tissue
compression and relaxation stresses (sometimes called the
jackhammer effect) or by other forces such as microstreaming of
bubbles in the tissue matrix. The effect is that the tissue becomes
liquefied and separated. It then becomes emulsified with the
irrigant solution. The resulting emulsion is then aspirated from
the site. Bulk excision of tissue is possible by applying the
energy around and under unwanted tumors to separate it from the
surrounding structure. The surgeon can then lift the tissue out
using common tools such as forceps.
[0004] A second kind of ultrasonic device uses a sharp blade
instead of a blunt hollow probe. Here a cutting action takes place.
Such a sharp ultrasonic blade is the subject of allowed U.S. Pat.
No. 440,349 filed Nov. 15, 1999, now U.S. Pat. No. 6,379,371. As
disclosed therein, the blade shape is semicircular at the distal
portion with two straight sides parallel to the longitudinal axis
and extending back to the shoulder that contacts the vibrating
probe. Male threads are shown which mate with the female threaded
socket of the probe (or transducer) to allow tight intimate contact
of the probe and blade tip shoulder. When the two are torqued
together, they form a single resonant body that will vibrate in
sympathy with the transducer and generator combination. The distal
end of the blade will vibrate with an amplitude set by the
mechanical gain of the probe/tip geometry and the input amplitude
provided by the transducer generator combination. This motion
provided the cutting action for the tissue in question.
[0005] The blade of allowed U.S. Pat. No. 440,349 filed Nov. 15,
1999, now U.S. Pat. No. 6,379,371, was intended for the cutting or
excising of bone or similarly hard tissue in surgical applications.
In tests conducted in vitro and in vivo, it was noted that the
blade, when sharp, cut both hard and soft tissue with similar ease.
In delicate operations, such as sinus lift surgery or craniotomies
where the goal is to cut an aperture in the front of the skull to
expose sinus tissue or brain but not cut the membrane directly
beneath the bony structure, this is very important. It is also
important in spinal and brain surgery where bone tissue must be cut
with a minimum of damage to underlying soft tissues such as the
dura mater. It was noted in early in vitro testing that the blade,
as it plunged through the cortex of the bone punctured the membrane
or ripped it. After some experience, competent surgeons were able
to master the technique, but the learning curve was steep.
[0006] A sharp blade such as that of allowed U.S. Pat. No. 440,349
filed Nov. 15, 1999, now U.S. Pat. No. 6,379,371, has been shown in
both in vitro and in vivo testing to be an effective tool for
cutting bone, cartilage, soft tissues such as vein, arteries and
can even be used to cut skin with minimal secondary trauma. In this
kind of blade, ablation is not the primary cause but a shearing or
cutting action predominates.
[0007] Both the ablating instrument and the cutting or incising
instrument have limitations when used as surgical tools. The blunt
probe is effective in ablating or excising soft liquid rich tissues
such as fat, liver or spleen, but less effective or even
non-effective in dry, hard material such as hard cartilage or bone.
The blade type devices are effective in the hard material but also
are not soft tissue sparing so that collateral tissue damage is
incurred, rendering the blade undesirable around nerve clusters or
other important structures. Because sharp blades tend to cut
everything, tissue selectivity is reduced to nil and no
differentiation may be made between hard and soft material.
[0008] In certain applications, such as sinus cavity lifts and
maxialfacial surgery such as third molar extraction, a tool would
be useful which could cut the harder bony material with less trauma
while sparing the soft tissues underneath if they were
inadvertently touched by the vibrating blade.
OBJECTS OF THE INVENTION
[0009] It is an object of the present invention to provide a
surgical tool for selectively excising tissues.
[0010] More particularly, it is an object of the present invention
to provide an ultrasonic cutting blade capable of selectively
excising tissues.
[0011] It is an even more particular object of the present
invention to provide such a blade that could be used to cut harder
bony material while minimizing trauma to adjacent soft tissues in
the event that those soft tissues are inadvertently touched by the
vibrating blade.
[0012] A related object of the present invention is to provide a
surgical method that selectively excises tissue.
[0013] A more specific object of the present invention is to
provide a surgical method for cutting harder bony material while
minimizing trauma to adjacent soft tissues.
[0014] These and other objects of the invention will be apparent to
those skilled in the art from the drawings and descriptions hereof.
Although each object is attained by at least one embodiment of the
invention, no embodiment need necessarily meet every object.
SUMMARY OF THE INVENTION
[0015] The present invention is directed to a surgical blade and
additionally to a method of use of that surgical blade in an
ultrasonically assisted procedure. The surgical blade has a certain
range of a critical dimension that permits it to be used in the
method.
[0016] The invention was made only upon the observation that the
sharper the blade, i.e., the smaller the minor dimension of a
vertical trapezoid formed by the included angle of a blade of width
N (see FIG. 1), the more likely that cutting of hard tissues
resulted in collateral damage, particularly incisions, in
surrounding soft tissue. The minor dimension or thickness of the
blade at the edge can range from the width of the body of the
blade, N, to 0. The degree of sharpness is inversely proportional
to the edge thickness. 5
[0017] Dimensionally, it was discovered that blades with an edge
thickness between approximately 0.001" and approximately 0.010"
inch offered the best compromise between effective, safe cutting of
hard tissue such as bone while being sparing of surrounding soft
tissue.
[0018] As an added benefit, it was serendipitously noted that the
blades with a less sharp configuration held their edge longer,
i.e., sustained less damage than the sharper blades. It should be
noted that the blades did not incur as much damage to the blade
surface as the sharper blades, not that the blades started out not
sharp and got worse as they were used.
[0019] Accordingly, an ultrasonic surgical blade in accordance with
the present invention comprises a generally flat blade having a
thickness along a cutting edge of between about 0.0005 inch and
about 0.020 inch. More preferably, the cutting edge has a thickness
of between about 0.001 inch and a 0.010 inch. Most preferably, the
cutting edge has a thickness of between about 0.001 inch and 0.003
inch. Generally, the blade has a flat body portion with a body
thickness greater than the edge thickness. The blade then includes
a beveled or tapered region extending from the body portion to the
edge.
[0020] Pursuant to special features of the invention, the cutting
edge is disposed in a single plane and has an arcuate section and a
pair of straight sections continuous with the arcuate section at
opposite ends thereof. Also, the blade is provided with a shank
having an axially extending bore for the conveyance of cooling
fluid to the cutting edge, the blade body being provided with an
axially extending through-slot communicating at one end with the
bore.
[0021] A surgical method in accordance with the present invention
utilizes a cutting blade having a thickness along a cutting edge of
preferably between about 0.0005 inch and about 0.020 inch and more
preferably between approximately 0.001 inch and approximately 0.010
inch and most preferably between about 0.001 inch and 0.003 inch.
During the performance of the surgical method, the blade is moved
in contact with relatively hard tissue that is disposed adjacent to
relatively soft tissue at a surgical site in a patient. The cutting
edge may be moved at any angle relative to a surface of the hard
tissue, from 90.degree. (perpendicular) to 0.degree. (parallel). In
the latter case, the blade may move generally along an interface
between the relatively hard tissue and the relatively soft tissue.
The blade is ultrasonically vibrated during the moving of the
blade, whereby the hard tissue is cut and, in the case of an
interface incision, separated from the soft tissue, with a modicum
of damage being inflicted on the soft tissue.
[0022] Pursuant to another feature of the present invention, the
vibrating of the blade is initiated prior to a contacting of the
surgical site with the blade and is maintained during an initial
contact of the blade with the tissues at the surgical site and
during the moving of the blade. The blade is moved in a continuous
and uninterrupted stroke, for instance, along an interface, the
ultrasonic vibrating of the blade being performed continuously and
uninterruptedly during the stroke. At the end of the cutting
stroke, the ultrasonic vibrating of the blade is terminated and the
blade is removed from the surgical site. Irrigation fluid may be
introduced to the surgical site during the moving of the blade
along the interface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a schematic cross-sectional view, on an enlarged
scale, of an ultrasonic surgical blade in accordance with the
present invention.
[0024] FIG. 2 is a perspective view, also on an enlarged scale, of
an ultrasonic surgical blade in accordance with the present
invention.
[0025] FIG. 3 is a perspective view, on a larger scale, of a
portion of the blade encircled by line III in FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] As illustrated in the drawings, a cutting blade 12 for use
in ultrasonically assisted surgery includes an integral shank
portion 14 having an external screw thread (not shown) for
replaceably mounting the blade to a probe. Alternatively, blade 12
may be permanently attached to the probe.
[0027] Blade 12 includes a planar blade body 16 having a thickness
N. Blade body 16 is provided at an end opposite shank 14 with a
blade or cutting edge 18 including a central circularly arcuate
section 20 and a pair of linear end sections 22 and 24. Edge 18 is
continuous along a full radius of arcuate section 20, as well as
along straight sections 22 and 24.
[0028] As further illustrated in the drawings, blade 12 also
incorporates structure providing a path for coolant from an
irrigation pump (not shown) to reach blade edge 18, as well as
tissues being cut during a surgical procedure. For conducting
irrigant to blade edge 18 and the surgical site, shank portion 14
is formed with an axial passageway or bore 26, which communicates
with an axial passageway or bore in the probe.
[0029] Passageway or bore 26 terminates in an open longitudinal
channel or slot 28 that enables the coolant to spread out and onto
the planar body 16 of blade 12. This open channel or slot 28
distributes irrigant all along the sides or lateral surfaces of
planar blade body 16 and not in only specific locations, as
discussed in allowed U.S. Pat. No. 440,349 filed Nov. 15, 1999, now
U.S. Pat. No. 6,379,371, the disclosure of which is hereby
incorporated by reference. At an end of channel or slot 28 opposite
passageway or bore 26 is disposed a pair of opposed inclined
surfaces 30 (only one shown) which distribute irrigant from the
channel or slot towards arcuate blade edge section 20. The fluid
traveling down channel or slot 28 will encounter inclined surfaces
30 which exhibit an incident angle that deflects the fluid into the
cut (FIG. 10) while minimizing splash back. Surfaces 30 may be
planar, convex or concave.
[0030] Blade 12 has a thickness E along cutting edge 18 of between
about 0.0005 inch and about 0.020 inch, more preferably between
about 0.001 inch and 0.010 inch, and most preferably between about
0.001 inch and 0.003 inch. Beveled or tapered surfaces 32 extend
from the body portion 16 to edge 18. Cutting edge 18, including
sections 20, 22 and 24, is disposed, as is the entire blade body
16, in a single plane.
[0031] The use of blade 12 in a surgical procedure is described in
detail hereinafter. The procedure described herein is a
modification of the procedure described in allowed U.S. Pat. No.
440,349 filed Nov. 15, 1999, now U.S. Pat. No. 6,379,371.
[0032] In use, blade 12 was found to perform best when the
following method was employed.
[0033] After the patient is prepped for surgery as per standard
practices, the ultrasound unit is set up as indicated in allowed
U.S. Pat. No. 440,349 filed Nov. 15, 1999, now U.S. Pat. No.
6,379,371. Upon an activation of the ultrasound unit, blade 12
begins to vibrate and irrigation fluid is introduced
simultaneously. Blade edge 18 is then brought into contact with
hard tissue at a preselected surgical site. The vibrating blade 12
is moved in a continuous stroke over the incision site to cut or
remove tissue to a desired depth. After termination of the stroke,
the power to the ultrasound unit is shut off and blade 12 is
removed from the surgical site.
[0034] The technique discussed above prevents tissue temperature
rise to levels that would cause necrosis. If blade 12 is not moved
across the surgical site in a wiping or swiping fashion, tissue
temperatures quickly increase to over 49 degrees C., which in the
human body is at or above the necrosis temperature. By constantly
moving the blade, the temperatures rise very little over that of
normal body temperatures. Also, this technique provides very good
tactile feedback to allow the surgeon to discriminate between the
harder tissue and the softer, viable structures.
[0035] If surgeon desires and there is enough access, he or she may
move blade 12 so that it cuts along an interface between harder and
softer tissues, thereby stripping the harder top layer off the soft
tissue underneath. Blade 12 has good selectivity between the two
layers, so that collateral damage to the soft tissue is
minimized.
[0036] Preferably, a mixture of saline, lidocaine (or equivalent)
and epinephrine (or equivalent) is used as the irrigant. Such a
mixture provides moisturization, a slight hemostasis due to the
vasocontricting action of the epinephrine, and pain relief from the
action of the lidocaine. All of these chemicals have been found to
be safe when used for the stated purpose in clinical practice.
[0037] Although the invention has been described in terms of
particular embodiments and applications, one of ordinary skill in
the art, in light of this teaching, can generate additional
embodiments and modifications without departing from the spirit of
or exceeding the scope of the claimed invention. For example,
although the described surgical method has proven efficacious and
safe in adult and pediatric maxialfacial surgery, reconstructive
plastic surgery of the face and in various dental procedures, many
other surgical procedures may benefit from this invention. Such
other surgical procedures include brain and spinal cord surgery
where bone tissue must be displaced to afford access to the tissues
of the central nervous system. The present invention facilitates
such surgery in that the relatively hard bone tissue may be cut
with a modicum of damage inflicted on the underlying relatively
soft nerve tissues and dura mater. Thus, the present invention is
of use in surgery where an incision is to be made perpendicularly
to an outer tissue surface or parallel to an exterior surface,
e.g., along a hard-tissue/soft-tissue interface.
[0038] Accordingly, it is to be understood that the drawings and
descriptions herein are proffered by way of example to facilitate
comprehension of the invention and should not be construed to limit
the scope thereof.
* * * * *