U.S. patent application number 15/201043 was filed with the patent office on 2016-10-27 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 | 20160310162 15/201043 |
Document ID | / |
Family ID | 49458127 |
Filed Date | 2016-10-27 |
United States Patent
Application |
20160310162 |
Kind Code |
A1 |
GUO; JOSEPH |
October 27, 2016 |
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. A
retrieval tool 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 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: |
49458127 |
Appl. No.: |
15/201043 |
Filed: |
July 1, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13460246 |
Apr 30, 2012 |
9381033 |
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15201043 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/320078
20170801; A61B 2017/320028 20130101; A61B 17/32056 20130101; A61B
17/32002 20130101; A61B 17/320036 20130101; A61B 17/3209 20130101;
A61B 17/32 20130101; A61B 2017/32006 20130101; A61B 2017/320056
20130101; A61B 2017/320032 20130101; A61B 2017/320098 20170801;
A61B 2017/320052 20130101 |
International
Class: |
A61B 17/3205 20060101
A61B017/3205 |
Claims
1. A system for transecting a ligament within a body, comprising: a
flexible cutting element having a smooth surface; a substantially
rigid, needle-like retrieval tool of a length sufficient to extend
from a first location transversely adjacent to such ligament to a
second location transversely adjacent to such ligament and opposite
to such first location, and of a configuration for releasably
engaging said cutting element and maintaining engagement therewith
under a tensile load; and an imaging device capable of visualizing
said retrieval tool relative to a ligament.
2. The system of claim 1, wherein said cutting element has a
diameter less than 0.5 mm .
3. The system of claim 1, wherein said cutting element has a zero
bend radius.
4. The system of claim 1, wherein said cutting element has a bend
radius less than about half the thickness of said ligament.
5. The system of claim 1, wherein said cutting element has a
tensile strength of greater than 500 MPa.
6. The system of claim 1, wherein said retrieval tool has a
hook-shaped void formed therein near its distal end.
7. The system of claim 1, wherein said imaging device comprises an
ultrasound imaging device.
8. The system of claim 1, further comprising a thin-walled,
flexible protective tube dimensioned to receive said cutting
element and formed of a material selected to allow movement of said
cutting element thereto without being cut thereby.
9. The system of claim 1, wherein said retrieval tool has a sharp
distal tip.
10. The system of claim 1, wherein said retrieval tool comprises a
hypodermic needle and distal portion configured for engaging said
cutting element, wherein said distal portion is attachable to said
hypodermic needle.
11. The system of claim 1, wherein said distal portion has a blunt
distal tip.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a divisional based on U.S. application
Ser. No. 13/460,246, filed on Apr. 30, 2012, incorporated by
reference in its entirety.
BACKGROUND
[0002] 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.
[0003] 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.
[0004] 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 he 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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
[0009] 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.
[0010] 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
specially configured retrieval 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 retrieval tool
component comprises a thin, rigid and elongated needle-like element
having near its distal end a hook-like feature formed therein. Such
feature is dimensioned to engage the cutting element and configured
to maintain engagement therewith when being pulled proximally.
[0011] In the transection of the transverse carpal ligament, the
retrieval tool 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 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 retrieval 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. A length of the cutting
element is engaged by the hooking element of the retrieval tool 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 tool and its free end pulled through.
Reextension of the retrieval tool 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. The
very small cross-sections of the retrieval tool and 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 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 one of those punctures, recovery time
is minimal and scaring is essentially negligible.
[0012] 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 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.
[0013] 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 retrieving tool is first extended across
the top of the ligament and a loop of cutting element is retrieved
before the tool is extended through the carpal tunnel for retrieval
of the second end of the cutting element. 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
retrieval tool 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. The
retrieval tool 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.
[0014] 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
[0015] FIG. 1 is a cross-sectional view of the carpal tunnel area
of the hand;
[0016] FIG. 2 is a perspective view of a preferred embodiment of
the retrieval tool of the present invention;
[0017] FIG. 3 is a perspective view of a preferred embodiment of
the cutting element of the present invention;
[0018] 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;
[0019] 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;
[0020] 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; and
[0021] FIGS. 7A and 7B are greatly enlarged cross-sectional views
of an alternative preferred embodiment of the retrieval tool.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] 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.
[0023] 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.
[0024] FIG. 2 is perspective view of a preferred embodiment of the
retrieval tool 22 of the present invention. 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.
[0025] 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 tensile strength of over
500 MPa. 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.
[0026] 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 tool 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 tool 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 tool to be more easily
imaged.
[0027] In FIG. 4B, the retrieval tool 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 tool through the
skin in the event the retrieval tool 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.
[0028] Once the cutting element 34 is engaged, the retrieval tool
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 tool 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.
[0029] FIG. 4E illustrates the subsequent step of the method
wherein the retrieval tool 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 tool.
[0030] Once the cutting element 34 is again engaged, the retrieval
tool 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 tool 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. 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.
[0031] In an alternative embodiment, and as a modification to the
step shown in FIG. 4C, the retrieval tool 22 is not completely
withdrawn from access port 42 as illustrated in FIG. 5A. The tool
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 tool 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 tool as well as at the completion of the
transection step.
[0032] In another alternative embodiment, and as a modification of
the step shown in FIG. 4E, the retrieval tool 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 tool 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 tool. 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.
[0033] 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 tool 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 tool and the rigid
distal end 38 of the locator tool. Once engagement with the hooking
element 28 of the retrieval tool 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
tool 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
* * * * *