U.S. patent application number 13/870291 was filed with the patent office on 2013-10-31 for method and apparatus for thread transection of a ligament.
The applicant listed for this patent is Joseph Guo. Invention is credited to Joseph Guo.
Application Number | 20130289597 13/870291 |
Document ID | / |
Family ID | 49477939 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130289597 |
Kind Code |
A1 |
Guo; Joseph |
October 31, 2013 |
METHOD AND APPARATUS FOR THREAD TRANSECTION OF A LIGAMENT
Abstract
A method and apparatus for transecting soft tissue, such as a
ligament, and more particularly, the transverse carpal ligament. An
hollow introducer needle and a threadlike cutting element enable
the method to performed in a minimally invasive manner. The cutting
element is routed into position about the target ligament such that
the cutting element both enters and exits the body from the same
side of the ligament. The substantially smooth exterior surface of
the cutting element serves to provide for a kerf-less cut.
Inventors: |
Guo; Joseph; (Monterey Park,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Guo; Joseph |
Monterey Park |
CA |
US |
|
|
Family ID: |
49477939 |
Appl. No.: |
13/870291 |
Filed: |
April 25, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13460246 |
Apr 30, 2012 |
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13870291 |
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Current U.S.
Class: |
606/170 |
Current CPC
Class: |
A61B 17/34 20130101;
A61B 17/320036 20130101; A61B 2017/320733 20130101; A61B 2017/32006
20130101; A61B 17/3403 20130101; A61B 17/149 20161101 |
Class at
Publication: |
606/170 |
International
Class: |
A61B 17/32 20060101
A61B017/32 |
Claims
1. A method for transecting a soft tissue within a body, comprising
the steps of: providing a flexible thread-like cutting element
having a substantially smooth surface; providing a hollow
introducer needle; extending said hollow introducer needle into
said body at a first location transversely adjacent said soft
tissue and out of said body at a second location transversely
adjacent to said soft tissue and opposite said first location so as
to traverse said soft tissue on a first side thereof; extending
said cutting element through said hollow introducer needle to leave
said cutting element projecting proximally and distally from said
introducer needle; retracting said introducer needle from said body
so as to leave said cutting element in place; re-extending said
hollow introducer needle into said body at said first location and
out of said body at said second location or into said body at said
second location and out of the body at said first location so as to
traverse said soft tissue on a second side thereof opposite said
first side; extending an end of said cutting element through said
hollow introducer needle such that said end portion projects from
said hollow introducer needle; retracting said introducer needle
from said body to thereby leave said cutting element in place
looped about said soft tissue with both end portions extending from
the same location of said body; and exerting force on the ends of
said cutting element so as to achieve a kerf-less transection of
said soft tissue.
2. The method of claim 1, wherein unequal forces are exerted on the
ends of said cutting element to alternately pull said cutting
element in opposite directions to transect said soft tissue.
3. The method of claim 2, further comprising the steps of providing
a powered hand tool for alternately reciprocating ends of a cutting
element and attaching said projecting ends thereto.
4. The method of claim 1, wherein unequal forces are exerted on the
ends said cutting element so as to pull said cutting element in a
single direction to transect said soft tissue.
5. The method of claim 1, wherein substantially equal forces are
simultaneously exerted on both ends of said cutting element to
transect said soft tissue.
6. The method of claim 1, wherein an imaging device is relied upon
to visualize said extensions of said hollow retrieval needle within
said body.
7. The method of claim 6, wherein said imaging device comprises an
ultrasound imaging device.
8. The method of claim 1, wherein a liquid is injected into the
body in and around such soft tissue prior to said routing of said
cutting element about said soft tissue so as to provide space for
the extension of the hollow introducer needle thereinto.
9. The method of claim 1, further comprising the step of
positioning a protective tube about both end portions of said
cutting element projecting from said body.
10. The method of claim 1, wherein one end of said cutting element
is first extended through said hollow needle from its first end and
wherein said same end of the cutting element is subsequently
re-extended through said needle from its second end.
11. The method of claim 1, wherein one end of said cutting element
is first extended through said hollow needle from its first end and
wherein its opposite end of the cutting element is subsequently
re-extended through said needle from its first end.
12. The method of claim 1, wherein said soft tissue comprises a
ligament.
13. The method of claim 12, wherein said ligament comprises the
transverse carpal ligament.
14. A system for transecting a soft tissue within a body,
comprising: a flexible cutting element having a substantially
smooth surface; and an introducer needle having a hollow interior
extending from its proximal end to its distal end with an internal
diameter sufficient to receive said flexible cutting element,
having a distal tip, and having a length sufficient to extend from
a first location transversely adjacent to such soft tissue to a
second location transversely adjacent to such soft tissue and
opposite to such first location;
15. The system of claim 14 further comprising an imaging device
capable of visualizing said hollow introducer needle with said body
relative to said soft tissue.
16. The system of claim 15, wherein said visualizing device
comprises an ultrasound imaging device.
17. The system of claim 14, wherein said cutting element has
stiffened end sections to facilitate insertion into and extension
through said hollow introducer needle.
18. The system of claim 14, wherein said cutting element has a
diameter less than 1.0 mm.
19. The system of claim 14, wherein said cutting element has a zero
bend radius.
20. The system of claim 14, wherein said cutting element has a bend
radius less than about half the thickness of said soft tissue.
21. The system of claim 14, wherein said cutting element has a
breaking strength of greater than 2 lbs.
22. The system of claim 14, wherein said cutting element has a
braided or twisted structure or comprises a monofilament.
23. The system of claim 14, further comprising a power tool for
alternately reciprocating ends of said cutting element.
24. The system of claim 14, further comprising a hollow sleeve
dimensioned to receive both ends of said cutting element and
configured for retaining said cutting element therein during its
reciprocation.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Ser. No.
13/460,246, filed on Apr. 30, 2012, incorporated by reference
herein in its entirety.
[0002] The present invention is generally directed to a surgical
method and to an apparatus for performing such method. More
particularly, the invention provides for the transection, by
minimally invasive means, of a ligament such as for example the
transverse carpal ligament that is commonly released as a treatment
for carpal tunnel syndrome.
BACKGROUND
[0003] Many people suffer from injury to the soft tissues of the
wrist and carpal tunnel, often caused by frequent, sustained
repetitive motion involving the hands. Repetitive activities which
require the same or similar hand/wrist action can result in
injuries which have been collectively referred to as Cumulative
Repetitive Stress Syndrome or Repetitive Strain Injury. The most
familiar and common of such wrist injuries is known as carpal
tunnel syndrome which produces pain, discomfort, nerve conduction
disturbances, and impairment of function of the hand and sometimes
the arm as well. The most common symptoms of this condition include
intermittent pain and numbness of the hand.
[0004] Carpal tunnel syndrome occurs when the median nerve which
runs from the forearm into the hand, becomes pressed or squeezed at
the wrist. The median nerve provides feeling in one's thumb and
along with index, middle and ring ringers. The median nerve
controls sensations to the palmar side of the thumb and these
fingers as well as impulses to some muscles in the hand which allow
the fingers and thumb to move. The median nerve receives blood,
oxygen and nutrients through a microvascular system which is
present in the connective tissue surrounding the nerve fiber.
Increased pressure on the nerve fiber can constrict these
microvessels and will reduce the blood flow to the median nerve.
Any prolonged deprivation of oxygen and nutrients can result in
severe nerve damage.
[0005] The median nerve passes through the carpal tunnel, a canal
in the wrist surrounded by the carpal bones on three sides and a
fibrous sheath called the transverse carpal ligament on the fourth
side. In addition to the median nerve, the nine flexor tendons in
the hand pass through this canal. When compressed, the median nerve
will cause pain, weakness or numbness in the hand and wrist which
may also radiate up along the arm. The median nerve can be
compressed by a decrease in the size of the carpal canal itself or
an increase in the size of its contents (i.e. such as the swelling
of the flexor tendons and of the lubrication tissue surrounding
these flexor tendons), or both. For example, conditions that
irritate or inflame the tendons can cause them to swell. The
thickening of irritated tendons or swelling of other tissue within
the canal narrows the carpal canal, causing the median nerve to be
compressed. The cross-sectional area of the tunnel also changes
when the hand and wrist changes positions. Wrist flexion or
extension can decrease the cross-sectional area, thus increasing
the pressure exerted on the median nerve. Flexion also causes the
flexor tendons to somewhat rearrange which can also compress the
median nerve. For example, simple bending of the wrist at a 90
degree angle will decrease the size of the carpal canal. Without
treatment, carpal tunnel syndrome can lead to chronic neural
muscular disorders of the hand and sometimes the arm.
[0006] Treatment for carpal tunnel syndrome includes a variety of
non-surgical as well as surgical procedures, wherein carpal tunnel
release is one of the most common surgical procedures that is
performed. Such surgery involves the severing of the transverse
carpal ligament to relieve the pressure on the median nerve and is
commonly performed via either open or endoscopic methods. In open
methods, the skin lying over the carpal tunnel is incised after
which the transverse carpal ligament is transected under direct
vision. The skin is then reapproximated with sutures. Endoscopic
methods require incision of the skin in one or more locations to
allow for the insertion of an endoscope along with various tools
that are needed to transect the ligament. Such tools typically
include a combination of a specially configured scalpel and guide
instrument. The insertion of such tools into proper position below,
above or both below and above the target ligament further requires
the formation of one or more pathways in the hand with attendant
trauma to the surrounding tissue and the potential for nerve damage
as well as a more protracted post-surgical healing process.
Additionally, the use of a scalpel typically requires multiple
passes thereof in order to complete a transection which causes a
complex pattern of cuts to be imparted onto the severed ligament
surfaces.
[0007] Less invasive techniques have been proposed including for
example the use of flexible saw elements that are introduced into
the hand and positioned adjacent to or wrapped about a portion of
the target ligament after which the saw element is reciprocated to
cut the tissue. A substantial disadvantage of a cut that is made by
a saw-like instrument as opposed to a knife-like instrument is
inherent in the fact that a kerf is created. The material that is
removed from the kerf is either deposited in and around the
surgical site or additional steps must be taken to retrieve such
material. Additionally, the cut surfaces that are created by a saw
tend to be relatively rough and abraded with microtrauma on the
cutting surface that may increase inflammatory response (edema,
erythema, heat and pain), could result in local tissue adhesions
and scarring which can delay or complicate the healing process.
[0008] Alternatively, techniques have been proposed wherein a taut
wire, string or filament is used to cut a ligament. The cut is
achieved either by the tautening of the cutting element or
alternatively, by reciprocating the taut element. Disadvantages
associated with such an approach are inherent in the less than
optimal geometry by which a taut wire can be brought to bear on the
target ligament and by the invasiveness of the tightening
apparatus.
[0009] A new method and apparatus is needed with which tissue such
as a ligament can be percutaneously accessed and transected so as
to cause a very minimal amount of disruption to the surrounding
tissue and by which a smooth, kerf-less cut is achieved.
SUMMARY OF THE INVENTION
[0010] The present invention provides for the minimally-invasive
transection of tissue such as a ligament. The method and apparatus
obviate the need for any incisions, minimizes disruption of the
tissue surrounding the target ligament, enables a smooth kerf-less
cut of the target ligament to be achieved, requires no suturing and
can be easily and quickly performed in a clinic setting.
[0011] More particularly, the invention provides for the
introduction of a thin and flexible thread-like cutting element
into the body and its routing about the target ligament. Subsequent
manipulation of the protruding ends of the smooth cutting element
serves to transect the ligament by a smooth kerf-less cut. A
routing tool component of the invention enables the cutting element
to be easily and quickly introduced and routed into position about
the target ligament with minimal disruption or trauma to the
surrounding tissue. The routing tool component may take the form of
a hollow introducer needle or a specially configured hooked
retrieval needle comprising a thin, rigid and elongated needle-like
element having near its distal end a hook-like feature formed
therein that is dimensioned to engage the cutting element and
configured to maintain engagement therewith when being pulled
proximally.
[0012] In the transection of the transverse carpal ligament, the
routing tool component is initially used to puncture the skin of
the hand so as to form a first access port at a location proximal
to the ligament and laterally adjacent thereto. The tool is then
extended into the hand through the carpal tunnel along a path
immediately below the ligament and is caused to emerge from the
hand through a second access port formed thereby just distal to the
ligament. The position of the routing tool in the hand and
especially in relation to the ligament is preferably visualized
throughout the placement procedure using for example an ultrasound
imaging device to enable precise maneuvering of the tool.
[0013] Should a hooked retrieval needle serve as the routing tool
and once it is in the position within the hand as is described
above, a length of the cutting element is engaged by the hooking
element of the retrieval needle and a loop thereof is drawn into
the hand via the second access port. The zero bend radius of the
cutting element allows the loop that is formed to be as compact as
possible. The loop is drawn under the ligament and out of the first
access port where it is disengaged from the retrieval needle and
its free end pulled through. Reextension of the retrieval needle
into the hand and along the top surface of the ligament to the
second access port allows a second length of the cutting element to
be engaged and a loop thereof drawn into the hand, over the
ligament and out of the first access port. By pulling the second
free end of the cutting element through the hand over the ligament
and out of the first access port, the routing of the cutting
element about the ligament is complete leaving the cutting element
in position for the transection.
[0014] Should a hollow introducer needle serve as the router tool,
the cutting element is inserted into the needle's proximal end
while the needle is in the position described above. The cutting
element is extended through the length of the needle and
approximately one half of the cutting element is pulled from the
distal end of the needle. The needle is then proximally retracted
from the hand to leave the cutting element in place in the hand
such that a sizable portion thereof protrudes from the first access
port as well as from the second access port. The hollow needle is
then reinserted into the first access port and adjacent to the
proximally protruding length of cutting element, is extended
through the hand immediately above the ligament and out of the
second access port. The distally protruding portion of the cutting
element is then fed into the distal end of the hollow needle in
place within the hand and extended through its length so as to
emerge from the proximal end of the needle after which the needle
is retracted from the hand. The routing of the cutting element
about the ligament is thereby complete leaving the cutting element
in position for the transection. Alternatively, one end of the
cutting element may be initially introduced into the distal end of
the needle and extended there through. After retraction of the
needle and reinsertion into and through the hand above the
ligament, the second end of the cutting element is introduced into
the distal end of the needle and fed there through. Retraction of
the needle leaves the cutting element in place for the transection.
As a further alternative, the needle may be reinserted into the
hand via the second access port.
[0015] The physical characteristics of the cutting element are
selected to facilitate a kerf-less cut through the ligament. The
small diameter and high tensile strength of the cutting element
provides for the transection of the ligament by the manipulation of
the ends of the cutting element. Unequal forces can alternatingly
be applied to the two ends of the cutting element to induce a
reciprocating cutting action. Alternatively, one end can be pulled
with greater force than the other element so as to pull the cutting
element in a single direction as it cuts through the ligament. As a
further alternative, both ends can be pulled simultaneously with
equal force to simply pull the cutting element through the
ligament. The substantially smooth, none abrasive surface of the
cutting element causes a knife-like cut to be achieved without the
formation of a kerf and thus without an attendant deposition of
detached material in and about the surgical site. Reciprocation may
preferably be achieved with the use of a power tool, by which the
two ends of the cutting element are alternating pulled. A stiffened
section one or both ends of the cutting element facilitates the
introduction of the cutting element into the hollow introducer
needle.
[0016] The very small cross-section of the routing tool, whether it
takes the form of the hollow introducer needle or the hooked
retrieval needle, and of the cutting element, as well as minimally
invasive method by which such hardware is introduced and positioned
within the hand greatly reduces the risk of injury to the median
nerve as well as to the smaller nerves that branch out therefrom.
Additionally, the fact that the cutting element is positioned via
only two tiny punctures and that the transection is performed via
only one of those punctures, recovery time is minimal and scaring
is essentially negligible.
[0017] The invention can additionally be modified in order to
further simplify the surgical procedure. For example the sequence
of steps can altered in the routing of the cutting element about
the ligament such that the routing tool is first extended across
the top of the ligament before the tool is subsequently extended
through the carpal tunnel for the routing of the cutting element
about the ligament. Additionally, a rigid alignment tool may be
attached to the second end of the cutting element to facilitate
engagement of the cutting element by the hooked retrieval needle
embodiment of the routing tool component at a location completely
within the hand and thus much closer to the distal edge of the
ligament in order to minimize the transection of any tissue
adjacent to the ligament. A retrieval needle may further be marked
so as to allow the rotational orientation of the hooking element to
be ascertained while within the hand and thereby enhance the
ability to engage the cutting element. Additionally, a protective
sleeve about a portion of the cutting element may be employed to
protect tissue located between the proximal entry port and the
ligament. Both ends of the cutting element may be caused to extend
through a single sleeve or each end may be caused to extend about
its own protective sleeve.
[0018] These and other advantages of the present invention will
become apparent from the following detailed description of
preferred embodiments which, taken in conjunction with the drawings
illustrate by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a cross-sectional view of the carpal tunnel area
of the hand;
[0020] FIG. 2 is a perspective view of a preferred embodiment of
the routing tool component of the present invention in the form of
a hooked retrieval needle;
[0021] FIG. 3 is a perspective view of a preferred embodiment of
the cutting element of the present invention;
[0022] FIGS. 4A-H are cross-sectional views of the hand with a
revealed transverse carpal ligament illustrating a preferred
sequence of steps for practicing the method of the present
invention using a hooked retrieval needle as the routing tool
component;
[0023] FIGS. 5A-C are cross-sectional views of the hand and the
transverse carpal ligament illustrating alternative preferred steps
for practicing the method of the present invention;
[0024] FIGS. 6A and B are cross-sectional views of the hand and the
transverse carpal ligament illustrating an alternative preferred
embodiment in which protective tubes are used;
[0025] FIGS. 7A and 7B are greatly enlarged cross-sectional views
of an alternative preferred embodiment of the hooked retrieval
needle;
[0026] FIG. 8 is a perspective view of another preferred embodiment
of the routing tool component of the present invention in the form
of a hollow introducer needle;
[0027] FIG. 9 is a perspective view of another preferred embodiment
of the cutting element of the present invention;
[0028] FIGS. 10A-J are cross-sectional views of the hand with a
revealed transverse carpal ligament illustrating a preferred
sequence of steps for practicing the method of the present
invention using a hooked retrieval needle as the routing tool
component;
[0029] FIG. 11 is a perspective view of a power tool for
reciprocating the cutting element once in position about the target
ligament; and
[0030] FIG. 12 illustrates the power tool being used to reciprocate
the cutting element in place about the ligament.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] The present invention provides for the minimally invasive
transection of tissue and obviates the need for scalpels, saws or
endoscopes. The invention is especially applicable for the
transection of ligaments and most particularly, for the release of
the transverse carpal ligament in the treatment of carpal tunnel
syndrome.
[0032] FIG. 1 is a cross-sectional view of the carpal tunnel area
of the hand 10. The carpal tunnel 12 is the area of the wrist and
palm of the hand 10 formed by a U-shaped cluster of bones 14 that
form a hard floor and two walls of the tunnel. The roof of the
tunnel is formed by the transverse carpal ligament 16 which
attaches to the wrist bones. Within the confines of the tunnel is
the median nerve 18 and the flexor tendons 20 of the thumb and
fingers. Carpal tunnel syndrome is caused by a compression of the
median nerve by either a decrease in the size of the tunnel or an
increase in the size of its contents. Such pressure may be relieved
by a release of the ligament such as by a transection thereof.
[0033] FIG. 2 is perspective view of a preferred embodiment of the
routing tool of the present invention wherein such tool takes the
form of a hooked retrieval needle 22. The tool generally includes a
thin, rigid and elongated distal section 24 and a handle 26 at its
proximal end. The distal section has hooking element 28 disposed
near its distal end 30. The hooking element is preferably defined
by a void formed within the outer diameter of the elongated distal
section of the retrieval tool so as to present a substantially
smooth outer surface and thereby minimize the potential for trauma
as the tool is extended into or retracted from tissue. The distal
end may have a sharp tip 29 as is shown in the illustrated
embodiment. Alternatively, the tip may have a more blunted
configuration. The hooking element is spaced slightly back
(reference numeral 30) from the distal end. A marking 32 on the
handle may be included demarking the rotational position of the
hook-like feature near the tool's distal end. The length of the
distal section is selected to be greater than the width of the
transverse carpal ligament. Its diameter is selected to be no
greater than about 1 mm.
[0034] FIG. 3 is a perspective view of the cutting element 34 of
the present invention with the optional locator tool 36 attached
thereto. The cutting element has a flexible, small diameter,
thread-like structure with a high tensile strength and a smooth
surface, preferably with an average surface roughness no greater
than 50 micrometers. The cutting element may comprise a
monofilament or a plurality of braided or otherwise joined fibers
or strands wherein each strand has a smooth surface so as to
present a relatively smooth, none-abrasive surface. Its physical
characteristics include a bend radius of less than half the
thickness of the ligament and preferably a zero bend radius, a
diameter of less than about 1.0 mm, and a breaking strength of over
2 lbs. The cutting element may comprise fiber or yarn formed of
cotton, silk, glass fiber, carbon fiber, various plastic fibers or
metal. More particularly, textile fiber, synthetic fiber, mineral
fiber, polymer fiber, microfibers may be used. The optional locator
tool includes a rigid distal end 38 of a diameter sufficiently
small to be extended into the access port and to be captured within
the hooking element 28 of the retrieval tool 22. A handle 40 is
disposed near its proximal end to enable the tool to be grasped and
manipulated.
[0035] FIGS. 4A-4H illustrate a preferred method of practicing the
present invention. After anesthetizing the area of the hand 10 near
and about the transverse carpal ligament 16, the distal end 30 of
the retrieval needle 22 is brought into contact with the hand just
proximal to the proximal edge of the target ligament as is shown in
FIG. 4A. The ligament is visible in the Figures for purposes of
clarity only as no incision is made throughout the entire procedure
to in any way expose the ligament to view. Additionally, an imaging
device, such as an ultrasound device, such as is commonly used for
a variety of imaging applications, is used to visualize the
position of the retrieval needle relative to the ligament but is
not shown so as not to obscure the surgical site again for purposes
of clarity. It is preferable to enter the hand at a position about
30 mm proximal of the proximal edge of the transverse carpal
ligament as the carpal tunnel can then be entered at a shallower
angle obviating the need to adjust the angel of the needle after
the tunnel has been reached and thereby minimizing trauma to tissue
in addition to allowing the retrieval needle to be more easily
imaged.
[0036] In FIG. 4B, the retrieval needle has been advanced into the
hand via entry port 42, through the carpal tunnel just under the
ligament and out through exit port 44. The entry and exit ports may
be formed by the direct extension of the retrieval needle through
the skin in the event the retrieval needle 22 is selected to have a
sharp distal tip 29. In the event a retrieval tool is used with a
blunt tip, a sharp instrument is necessary for forming the access
ports and guide the retrieval tool into the hand. The Figure
additionally shows the cutting element 34 having been engaged in
the hooking element 28 near the tool's distal end. In this
particular embodiment, the cutting element is devoid of a locator
tool attached to its distal.
[0037] Once the cutting element 34 is engaged, the retrieval needle
22 is retracted from the hand so as to draw a loop 46 of the
cutting element into the hand via port 44, through the carpal
tunnel and out of entry port 42 as is shown in FIG. 4C. The loop is
then disengaged from the retrieval needle and while one end of the
cutting element 34a is restrained, the loop is pulled so as to draw
the opposite end 34b of the cutting element free of the hand as is
shown in FIG. 4D.
[0038] FIG. 4E illustrates the subsequent step of the method
wherein the retrieval needle 22 is readvanced into the hand via
access port 42, is guided across the top surface of ligament 16 to
remerge from the hand via access port 44. The section of cutting
element 34 extending from under the ligament is engaged with the
hooking element 28 of the retrieval needle.
[0039] Once the cutting element 34 is again engaged, the retrieval
needle 22 is retracted from the hand so as to draw a loop 48 of the
cutting element into the hand via port 44, through the carpal
tunnel and out of entry port 42 as is shown in FIG. 4F. The loop is
then disengaged from the retrieval needle and while end 34b of the
cutting element is restrained, the loop is pulled so as to draw the
end 34a of the cutting element free of the hand as is shown in FIG.
4G. The cutting element is thereby in position about ligament 16
for subsequent manipulation to effect the transection. As is shown
in FIG. 4H, the ends 34a, 34b of the cutting element may simply be
grasped by the user, may be wound around the hands or fingers of
the user for a firmer grip or alternatively, may be fitted with
handles to provide for maximum grip and control. Unequal forces can
alternatingly be applied to the two ends of the cutting element to
induce a reciprocating cutting action either by hand or with the
use of an appropriately configured power tool. Alternatively, one
end can be pulled with greater force than the other element so as
to pull the cutting element in a single direction as it cuts
through the ligament. As a further alternative, both ends can be
pulled simultaneously with equal force to simply pull the cutting
element through the ligament. When transection has been achieved,
the cutting element is simply withdrawn through access port 42.
Application of a small bandage over each of the access ports 42, 44
completes the procedure.
[0040] In an alternative embodiment, and as a modification to the
step shown in FIG. 4C, the retrieval needle 22 is not completely
withdrawn from access port 42 as illustrated in FIG. 5A. The needle
is retracted just enough to expose the hooking element 28 and allow
the loop 46 of the cutting element 22 to be disengaged and
withdrawn, while most of the distal end 30 remains below the skin.
As a result, it is more likely that the needle will follow the same
pathway to the ligament 16 before traversing its top surface
resulting in less trauma and disruption to intervening tissue both
while advancing the needle as well as at the completion of the
transection step.
[0041] In another alternative embodiment, and as a modification of
the step shown in FIG. 4E, the retrieval needle 22 is not extended
through port 44 to engage cutting element 34 as is illustrated in
FIG. 5B. Rather the cutting element is engaged within the hand,
preferably as close to possible to the distal edge of the
transverse carpal ligament 16. The needle is shown with its hooking
element rotated toward the viewer. The marking 32 on the handle 26
allows the user to ascertain the rotational orientation of the
hooking element without a direct view of the distal end of the
retrieval needle. By engaging the cutting element 34 closer to the
distal edge of the ligament before drawing it across the top
surface of the ligament, less extraneous tissue is apt to be
captured between the cutting element and the ligament and thus less
trauma thereto will be caused during the transection of the
ligament.
[0042] As a further alternative to the preferred embodiment shown
in FIG. 5B, FIG. 5C illustrates the step using the cutting element
34 having the locator tool 40 attached thereto. Once the distal end
30 of the tool is in position such that the hooking element is
located just distal of the distal edge of the transverse carpal
ligament as confirmed by the ultrasound image, the cutting element
34 is pulled from the end 34b projecting from access port 42 so as
to draw its opposite end 34a and the locator tool that is attached
thereto into access port 44. Once the locator tool is extended to
the approximate depth that is illustrated, the ability to more
readily engage the retrieval needle is enhanced by virtue of the
locator tool's visibility under ultrasound imaging and by virtue of
the tactile feedback that is provided when contact is made between
the rigid distal section 24 of the retrieval needle and the rigid
distal end 38 of the locator tool. Once engagement with the hooking
element 28 of the retrieval needle is confirmed, the locator tool
is withdrawn from access port 44, leaving the cutting element in
place within the hooking element. Subsequent retraction of the
retrieval needle causes a loop of the cutting element to be drawn
through the pathway above the ligament and out of access port 42.
Severing the cutting element from the locator tool allows the free
end 34a of the cutting element to be drawn through the hand and out
of the access port to complete the routing of the cutting element
about the target ligament.
[0043] In the event a cutting element 34 is selected that has a
larger than zero bend radius, it may be desirable to first
introduce a zero bend radius pilot thread into the hand and
position it about the ligament in the manner as was described above
with regard to placement of the actual cutting element. Once such
pilot thread is in place, one end is attached directly to one end
of the cutting element and simply pulled through so as to replace
the pilot thread with the cutting element. Such approach allows the
size of the access ports to be minimized that would otherwise have
to be enlarged in order to accommodate the larger loops 46, 48 that
are formed by a cutting element having a non-zero bend radius.
[0044] A further alternative preferred method of practicing the
present invention includes the use of protective tube or tubes 50
that are positioned about the cutting element at access point 42 as
is illustrated in FIGS. 6A and B. Both ends of the cutting element
may be passed through a single tube (FIG. 6A) or each end may be
passed through its own tube (FIG. 6B). The tube or tubes serve to
protect the surrounding tissue from injury as tension is applied to
the cutting element and it is drawn or reciprocated to effect the
transection. The tubes are especially effective when the cutting
element undergoes some curvature in and about access point 42. The
thin-walled tubing is selected to be flexible but resistant to
being cut by the cutting element.
[0045] In another alternative preferred embodiment, a modified
retrieval tool 52 is configured for capture within a hypodermic
needle 54 as is shown in FIGS. 7A and 7B. The hypodermic needle is
initially used to form access port 42, to inject anesthetic and/or
a liquid, such as saline solution, to inflate the surgical site so
as to separate the various tissues and components to provide easier
access for routing the cutting element into place. After the
injection is complete, the hypodermic needle is extended out of the
body to form access port 44. The specially configured blunt tipped
retrieval tool is inserted into the hypodermic needle and locked
into place (FIG. 7B) via locking mechanism 56. Such locking
mechanism may take any of various forms including the interference
fit that is created by the slightly wavy configuration of the shank
58 that is shown in the Figure. After the cutting element is
engaged by the hooking element 28 of the retrieval tool, the
hypodermic needle is retracted to draw loop 46 into the hand as is
shown in FIG. 4C. The distal section 60 of the retrieval tool 52
may have its outer diameter selected to substantially match the
outer diameter of the hypodermic needle to create a smooth
transition.
[0046] FIG. 8 is perspective view of another preferred embodiment
of routing tool component of the present invention wherein the tool
takes the form of a hollow introducer needle 70. The hollow needle
includes a sharp or blunt distal end 72 and has hollow interior
extending from its distal end to its proximal end 74. A handle 76
may be disposed about its proximal section to facilitate its
manipulation. The length of the section of introducer needle distal
to the handle is selected to be greater than the width of the
target transverse carpal ligament. Its diameter is selected to be
no greater than about 2 mm.
[0047] FIG. 9 is a perspective view of a preferred embodiment of
the cutting element 78 of the present invention. Substantially the
entire length 80 of the cutting element has a flexible, small
diameter, thread-like structure with a high breaking strength and a
smooth surface, preferably with an average surface roughness no
greater than 50 micrometers. The cutting element may comprise a
monofilament or a plurality of braided, twisted or otherwise joined
fibers or strands wherein each strand has a smooth surface so as to
present a relatively smooth, none-abrasive surface. Its physical
characteristics include a bend radius of less than half the
thickness of the ligament and preferably a zero bend radius, a
diameter of less than about 1.0 mm, and a breaking strength of over
2 lbs. The cutting element may comprise fiber or yarn formed of
cotton, silk, glass fiber, carbon fiber, various plastic fibers or
metal. More particularly, textile fiber, synthetic fiber, mineral
fiber, polymer fiber, microfibers may be used. At least one end of
the cutting element has a stiffened section 82 to facilitate the
introduction into and the extension through the hollow introducer
needle. 70. The stiffened section may be formed by covering the
section with relatively stiff tubing, by subjecting a synthetic
fiber to heat, by the infusion of for example a resin or by the
attachment of for example a suture needle. The stiffened section 82
preferably has a diameter less than the inner diameter of the
introducer needle. The enhanced diameter shown in the drawing is
for illustration purposes only.
[0048] FIGS. 10A-J illustrate a preferred method of practicing the
present invention. After anesthetizing the area of the hand 10 near
and about the transverse carpal ligament 16, the distal end 72 of
the hollow introducer needle 70 is brought into contact with the
hand just proximal to the proximal edge of the target ligament as
is shown in FIG. 10A. The ligament is visible in the Figures for
purposes of clarity only as no incision is made throughout the
entire procedure to in any way expose the ligament to view.
Additionally, an imaging device, such as an ultrasound device, such
as is commonly used for a variety of imaging applications, is used
to visualize the position of the introducer needle relative to the
ligament but is not shown so as not to obscure the surgical site
again for purposes of clarity. It is preferable to enter the hand
at a position about 30 mm proximal of the proximal edge of the
transverse carpal ligament as the carpal tunnel can then be entered
at a shallower angle obviating the need to adjust the angel of the
needle after the tunnel has been reached and thereby minimizing
trauma to tissue in addition to allowing the introducer needle to
be more easily imaged.
[0049] In FIG. 10B, the introducer needle has been advanced into
the hand via entry port 42, through the carpal tunnel just under
the ligament and out through exit port 44. The entry and exit ports
may be formed by the direct extension of the introducer needle
through the skin. The Figure additionally shows the cutting element
78 being advanced toward the proximal opening of introducer needle
wherein the stiffened section 82 of the cutting element serves to
facilitate the threading of the cutting element into the needle's
hollow interior.
[0050] FIG. 10C shows the cutting element emerging from the
introducer needle's distal end while FIG. 10D illustrates the
subsequent retraction of the needle to leave the cutting element in
place as is shown in FIG. 10E. As such, a section of cutting
element 78 is left projecting from entry port 42 and from access
port 44 while its central section extends through the carpal tunnel
just below the transverse carpal ligament 16.
[0051] FIG. 10F illustrates the subsequent step of the method
wherein the introducer needle has been reintroduced into the hand
via entry port 42 immediately adjacent to the placed cutting
element 78. The introducer needle has been advanced through the
hand immediately above the transverse carpal ligament 16 to
reemerge from access port 44. Alternatively, the introducer needle
may be reintroduced into the hand via access port 44 to reemerge
from port 42.
[0052] Once the introducer needle 70 is again in place, the cutting
element 78 is fed into the distal end of the introducer needle, is
extended along the needle's hollow interior to project from its
proximal end as is shown in FIG. 10H. Subsequent retraction of the
introducer needle as per FIG. 10 I leaves the cutting element in
position about the ligament 16 as is shown in FIG. 10J. The cutting
element is thereby in position for subsequent manipulation to
effect the transection of the ligament.
[0053] Alternatively, a cutting element having a stiffened section
at both ends allows the cutting element to be initially introduced
into the distal end of the introducer needle and extended there
through. After retraction of the needle and reintroduction into the
hand and extension above the ligament to re-emerge from the hand,
the second stiffened end of the cutting element can be inserted
into the distal end of the needle and extended there through.
Subsequent retraction of the needle again leaves the cutting
element in position for the transection.
[0054] The cutting element may simply be grasped by the user, may
be wound around the hands or fingers of the user for a firmer grip
or alternatively, may be fitted with handles to provide for maximum
grip and control. Unequal forces can alternatingly be applied to
the two ends of the cutting element to induce a reciprocating
cutting action either by hand or with the use of an appropriately
configured power tool. Alternatively, one end can be pulled with
greater force than the other element so as to pull the cutting
element in a single direction as it cuts through the ligament. As a
further alternative, both ends can be pulled simultaneously with
equal force to simply pull the cutting element through the
ligament. When transection has been achieved, the cutting element
is simply withdrawn through access port 42. Application of a small
bandage over each of the access ports 42, 44 completes the
procedure.
[0055] FIG. 11 generally illustrates a power tool 90 for
reciprocating the ends of the cutting element 78. The power tool
may include a hand grip section 92, which may house a battery pack.
An electric motor would be housed in section 94, rotation of which
is mechanically converted to a reciprocating effect. In the
embodiment shown, reciprocation is achieved by the rotation of a
crankshaft wherein a pin 98 extends from a rotatable disc on each
side of the device wherein the pins are diametrically opposed
relative one another and to which the ends of the cutting element
78 are attached. Converting the rotation of a longitudinally
positioned electric motor to a transversely disposed crankshaft can
be achieved in any of various well known ways including for example
geared, cammed or desmodromic mechanisms among many others.
[0056] FIG. 12 illustrates the power tool 90 being used to
reciprocate the cutting element 78 in place about the transverse
carpal ligament. A protective sleeve 50 may be fitted so as to
maintain the two ends of the cutting element in alignment with one
another and minimize trauma to the surrounding tissue.
[0057] While particular forms of the invention have been described
and illustrated, it will also be apparent to those skilled in the
art that various modifications can be made without departing from
the spirit and scope of the invention. For example, the sequence of
steps may be altered so as to cause the retrieval tool to traverse
and then retrieve a loop of the cutting element across the top
surface of the transverse carpal ligament before traversal of the
bottom surface is achieved. Additional access ports may be formed
for easier looping of the cutting element. Any of various ports can
be used as the final exiting port of the two ends of the cutting
element. Additionally, the method and appropriately dimensioned
retrieval tool can be used to transect other tissue so as to
perform for example, but no limited to, trigger finger release
surgery, tarsal tunnel release surgery and plantar fascia release
surgery. The apparatus and method can readily be adapted to
transect other soft tissue such as for example muscle, tendon,
vessels and nerves in humans as well as animals. Accordingly, it is
not intended that the invention be limited except by the appended
claims.
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