U.S. patent application number 13/901070 was filed with the patent office on 2014-02-06 for clamping retractor assembly.
This patent application is currently assigned to Retrospine Pty Ltd. The applicant listed for this patent is Retrospine Pty Ltd. Invention is credited to Donald FRY, Kevin SEEX.
Application Number | 20140039267 13/901070 |
Document ID | / |
Family ID | 48468193 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140039267 |
Kind Code |
A1 |
SEEX; Kevin ; et
al. |
February 6, 2014 |
Clamping Retractor Assembly
Abstract
An assembly for retracting soft tissue in a surgical incision,
the assembly comprising; a supporting member having first and
second ends; a refractor blade having a first distal end and a
second proximal end retained at the first end of the support
member; a retaining arm which co operates with the support member
and receives and supports a clamping assembly; an adjusting
assembly which engages the support member and allows the clamping
assembly to advance and retract relative to the retractor
blade.
Inventors: |
SEEX; Kevin; (Kingswood,
AU) ; FRY; Donald; (Kingswood, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Retrospine Pty Ltd |
Kingswood |
|
AU |
|
|
Assignee: |
Retrospine Pty Ltd
Kingswood
AU
|
Family ID: |
48468193 |
Appl. No.: |
13/901070 |
Filed: |
May 23, 2013 |
Current U.S.
Class: |
600/206 ;
600/210; 600/218 |
Current CPC
Class: |
A61B 2017/00862
20130101; A61B 2017/00349 20130101; A61B 90/06 20160201; A61B
2017/00991 20130101; A61B 2017/00407 20130101; A61B 2090/062
20160201; A61B 17/08 20130101; A61B 2017/3492 20130101; A61B 17/02
20130101; A61B 17/3403 20130101; A61B 2017/3405 20130101 |
Class at
Publication: |
600/206 ;
600/218; 600/210 |
International
Class: |
A61B 17/02 20060101
A61B017/02; A61B 17/08 20060101 A61B017/08 |
Foreign Application Data
Date |
Code |
Application Number |
May 28, 2012 |
AU |
2012902187 |
Claims
1. An assembly for retracting soft tissue in a surgical incision,
the assembly comprising; a supporting member having first and
second ends; a retractor blade having a first distal end and a
second proximal end retained at the first end of the support
member; a retaining arm which co operates with the support member
and receives and supports a clamping assembly; an adjusting
assembly which engages the support member and allows the clamping
assembly to advance and retract relative to the retractor
blade.
2. An assembly according to claim 1 wherein the clamping assembly
advances and retracts over a distance relative to the distal end of
the retractor blade and depending upon the retraction force
required.
3. An assembly according to claim 2 wherein the clamping assembly
is adjustable relative to the retaining arm.
4. An assembly according to claim 3 wherein the clamping assembly
includes a clamping member which is adjustable vertically relative
to the retaining arm.
5. An assembly according to claim 4 wherein the adjusting assembly
includes a runner retained on the support member.
6. An assembly according to claim 5 wherein the runner receives and
supports a first end of the retaining arm.
7. An assembly according to claim 6 wherein the runner is
adjustable incrementally along the length of the support
member.
8. An assembly according to claim 7 wherein the runner includes a
locking assembly which allows locking of the runner at a selected
position along the support member.
9. An assembly according to claim 8 wherein the clamping member is
capable of advancing and retracting relative to the retractor blade
responsive to travel of the runner along the support arm.
10. An assembly according to claim 9 wherein the runner is
incrementally adjustable along the length of the support member via
a ratchet assembly.
11. An assembly according to claim 9 wherein the runner is
incrementally adjustable along the length of the support member via
spaced apart holes in the support member.
12. An assembly according to claim 11 wherein the retaining arm has
first and second parts and is capable of telescopic length
adjustment.
13. An assembly according to claim 12 wherein the length adjustment
of the retaining arm is effected by relative movement between the
first and second parts.
14. An assembly according to claim 13 wherein one part is
selectively secured to the second part by a retaining pin which
engages openings on each said first and second parts.
15. An assembly according to claim 14 wherein the clamping assembly
is retained on one of said first and second parts of the retaining
arm and is capable of transverse movement relative to the retaining
arm.
16. An assembly according to claim 15 wherein a clamping member of
the clamping assembly includes a pressure plate.
17. An assembly according to claim 16 wherein the retractor blade
is integral with the support member.
18. An assembly according to claim 17 wherein the retaining arm
engages the support member via a slot in the retaining arm.
19. An assembly according to claim 10 wherein the clamping assembly
includes a boss which allows selective vertical adjustment of the
clamping member along the retaining arm.
20. An assembly according to claim 19 wherein the boss is spring
biased to a position which locks the clamping member against the
retaining arm.
21. An assembly according to claim 20 wherein the boss includes a
manually operable locking screw which locks the runner to the
support member.
22. An assembly according to claim 21. wherein the boss includes a
pin which selectively engages spaced apart recesses in said
retaining arm.
23. An assembly according to claim 22 wherein the retractor blade
is releasable from the first end of the support member.
24. An assembly according to claim 23 wherein the support member
includes along at least one face an array of teeth which co operate
with the ratchet assembly.
25. An assembly according to claim 24 wherein the location of the
runner along the support member is incrementally adjustable by co
operation between the teeth and ratchet assembly.
26. An assembly according to claim 25 wherein the retractor blade
is curved in the direction of the clamping member.
27. An assembly according to claim 26 wherein the curvature of the
retractor blade places the distal end of the retractor blade closer
to the retaining arm than the second end of said blade.
28. An assembly according to claim 27 wherein the blade is
elastically deformable.
29. An assembly according to claim 28 wherein the clamping member
further comprises a bearing member which directly engages the body
of a patient when the retraction assembly is in use thereby
allowing the retractor to retain soft tissue.
30. An assembly according to claim 29 wherein a retraction force is
increased or decreased by selective adjustment of the position of
the runner.
31. An assembly according to claim 29 wherein a retraction force is
increased or decreased by selective adjustment of the position of
the clamping member.
32. An assembly according to claim 31 wherein the bearing member
provides an opposing force against retraction of soft tissue to
maintain the desired retraction force through the retractor
blade.
33. An assembly according to claim 32 wherein the retraction
assembly is adjustable to allow the clamping assembly to travel in
the direction of the support member and in a direction parallel to
the support member.
34. A method for retracting soft tissue in a surgical would during
spinal surgery using an assembly comprising; a retractor blade
having a first distal end and a second end which engages a support
member; and an adjustable stop which engages a pressure plate which
co operates with the retractor blade during refraction by applying
pressure to the body of a patient, the method comprising the steps
of ; taking the retractor blade and attaching it to the support
member; inserting the retractor blade into a surgical incision;
adjusting a clamping assembly which co operates with a retaining
member to exert a retraction force on the retractor blade; allowing
a bearing member to engage a skin surface of a patient;
manipulating the support member to induce retraction of the soft
tissue against a bearing force applied by the bearing member
opposite to the direction of retraction.
35. A retractor blade for use with a retracting assembly for
retracting soft tissue in a surgical incision, the assembly
comprising; a supporting member for supporting the retractor blade;
an adjusting assembly which allows the assembly to advance and
retract relative to induce retraction force in the retractor blade;
the retractor blade having a proximal end which engages the
retracting assembly and a distal end which is characterised in
having a formation which is capable of engaging an anatomical
structure to resist pull out of the blade.
36. A retractor blade according to claim 35 wherein the formation
at the distal end is a sharp point.
37. A retractor blade according to claim 36 wherein the formation
is disposed in a plane at an angle to a plane at the distal end of
the blade.
38. A retractor blade according to claim 37 wherein the formation
points in the general direction of a force opposing retraction.
Description
BACKGROUND
[0001] The present invention relates to retraction assemblies and
more particularly relates to assemblies for retracting soft tissue
during surgery and particularly during spinal surgery. The
invention further relates to a G clamp retractor which has an
internal component which engages a wound to retract soft tissue and
an external component which has the capacity to set and control the
degree of retraction. The invention further relates to an assembly
which more efficiently retracts the psoas muscle to allow access to
spinal vertebrae.
PRIOR ART
[0002] In the field of surgery, conventional retractors used in
applications such as spinal surgery include a retractor blade
portion that is in contact with the soft tissues and a handle
portion that controls the blade position. The blades are inserted
into position through the surgical wound. The direction of force
applied by the blades to keep the wound open is usually at right
angles to this line of entry. This creates mechanical disadvantage
and complex mechanisms may need to be employed to overcome tissue
resistance--i.e. the tendency or bias of a wound towards closure.
As most retractors operate from the wound surface, the distance
from the wound surface to the point of contact between retractor
blades and the tissue works similar to a vertical cantilever which
is suboptimal for the surgeon's requirement for access to the site
and also a free end cantilever is not ideal as there is significant
force applied at the free end of the retractor by soft tissue. A
short retractor handle is generally easier to control and apply
force with as the moment is lower. In a long blade the moment is
higher. This is especially true when handle is roughly parallel
with blade. Strong mechanisms are sometimes required, strong
materials needed. Also the known mechanisms occupy space
restricting the surgeons access and they may also be complex. The
stability of the retractor may also be a problem. Some dual or
multi bladed retractors apply spreading forces against the wound
edges to stabilize retractors but these apply force that may
potentially injure tissues unnecessary for the purpose of exposure
but in order to gain retractor stability. Stability is desirable
but tissue injury is not. An alternative solution is to use table
mounted mechanisms with long mechanical arms but these have great
mechanical inefficiency because of the distance from point of
fixation i.e. the table, to the point of at which retraction
pressure is applied distally. This problem of the difficulty in
applying force and retractor instability is worse the deeper the
wound and especially when deep structures require refraction.
[0003] Spinal operations for various conditions commonly require
deep wounds especially when the approach is lateral, anterior
lateral or anterior to the spine. Retracting the psoas muscle
posteriorly to expose the lateral or anteriolateral spine can be
problematic because of the size of the muscle and the depth of the
wound. At L45 from a lateral approach this is made even harder
because the iliac crest commonly impedes true lateral access for
the retractors and instruments, meaning an oblique approach to the
spinal disc may be required.
[0004] In many spinal operations the retractors lack stability e.g.
with deep multi bladed retractors and various forms of tubular
refractors. Such retractors regularly require table fixed
adjustable arms to improve the stability for the retractor.
[0005] Conventional retractors work directly through the surgical
wound. Retractors are known that are employed in endoscopic surgery
which enter the abdominal cavity via separate ports or incisions.
These work directly and do not connect with other parts of a
retractor system. There is a system described in the paper by Rao
modified from Nakamura. (J Neurosurg Spine 5:468-470, 2006 entitled
"Dynamic retraction of the psoas muscle to expose the lumbar spine
using the retroperitoneal approach" [0006] Technical note: [0007]
GANESH RAO, M.D., ROBERT BOHINSKI, M.D., PH.D., IMAN FEIZ-ERFAN,
M.D., AND LAURENCE D. RHINES, M.D. [0008] Nakamura H, Ishikawa T,
Konishi S, Seki M, Yamano Y: Psoas [0009] strapping technique: a
new technique for laparoscopic anterior lumbar interbody fusion. J
Am Coll Surg 191:686-688, 2000)
[0010] That paper describes a technique which applies retraction
force via a thread through the patient body wall. A conventional
approach is used for the main operation. Tissues are retracted by
passing thread through the psoas muscle on a needle. The needle is
then removed from thread. A hollow needle is passed through the
body wall. Both ends of the thread are then passed through the
hollow needle outside the skin. Threads are pulled to gain psoas
retraction and then anchored with a forceps which is pulled back by
the muscle force against the skin. This system provides for
efficient application of retraction force by line of pull being as
close as possible to the desired direction of retraction and by
avoiding a cantilevered handle.
[0011] It would be advantageous if retraction was applied to the
psoas muscle by a blade rather than by a thread as blades retract
muscle smoothly and are less injurious to surface nerves than the
potential strangulation effect from a thread. Blades can also be
selected to fit the anatomy under retraction. The blind needle
passage may also damage nerves within the psoas muscle. Threading a
needle in a wound is fiddly, threads passing through retractor
tissues have less stability than a handle. Threads passed through a
muscle cannot be repositioned easily.
[0012] It would be an advantage in such operations to have a method
of retracting the psoas muscle posteriorly to expose the spine or
the disc space that avoids the force application and distribution
problems associated with deep wounds, long handles and oblique
access. These known surgical retraction methods currently all lead
to retractors working at considerable mechanical disadvantage.
[0013] It would be an advantage to reduce or eliminate the
mechanical disadvantage occasioned by the known retraction devices
and assemblies and to improve retractor stability and to avoid the
aforesaid problems.
[0014] The present applicant has previously described devices to
improve mechanical advantage for retraction using bone fixation
combined with mechanisms to allow retractor blade rotation.
INVENTION
[0015] The present invention provides an assembly which more
efficiently retracts muscle to allow access to spinal vertebrae.
The present invention further provides an assembly which more
efficiently retracts the psoas muscle to allow access to spinal
vertebrae. The present invention also provides a method of
retraction of soft tissues during spinal surgery which ameliorates
the problems of the prior art assemblies and methods.
[0016] According to one embodiment a retractor blade and handle are
inserted through a main wound. A second handle is inserted through
a separate incision. Blade and second handle are then connected in
the main wound. Pulling the second handle retracts the blade and
tissues efficiently in a preferred direction. The assembly
described herein allows the maintenance of the required amount of
refraction and maintenance of the retractor position and without
either manual holding or securing of the retractor handle to a
table mounted arm. Passage of the second handle through the body
wall limits motion except for motion in line with the handle.
Limiting the motion of the refractor handle further is achieved by
its relationship with a plate. The plate is in contact with the
body wall. Internally the muscle under retraction exerts a pull on
the refractor and its handle. Internal movement of the handle is
however prevented by an adjustable stop on the handle which is
forced against the plate by the retractor pull. Retraction can be
adjusted by movement of the stop.
[0017] In its broadest form the present invention comprises: [0018]
an assembly for retracting soft tissue in a surgical wound, the
assembly comprising; [0019] a retractor blade having a first distal
end and a second end which includes an associated support member,
[0020] a retaining member having a distal end which engages the
support member and a second proximal end which includes a hand
operable clamping assembly; [0021] an adjustable stop which engages
a plate, wherein the plate engages a skin surface of a patient to
resist said retraction by the soft tissue as the support member is
urged to induce retraction by the blade.
[0022] According to a preferred embodiment, the support member
includes a formation which co operates with a guide member.
Preferably the formation is an opening which receives an end of the
guide member. According to one embodiment the retaining arm
includes at least one threaded region which co operates with said
plate, adjustable stop and a locking nut. The guide member co
operates with the support member to enable setting of a retraction
condition. The assembly allows adjustment of retraction by
increasing or decreasing a retraction force.
[0023] In another broad form the present invention comprises:
[0024] an assembly for retracting soft tissue in a surgical wound,
the assembly comprising; [0025] a retractor blade having a first
distal end and a second end which engages an associated detachable
first handle, [0026] a second handle having a first distal end
which engages said blade and a second proximal end which includes a
hand operable control element and intermediate therebetween an
adjustable stop which engages a plate, [0027] a guide which engages
a second end of the first handle to facilitate alignment of the
second handle with an opening in the refractor blade; [0028]
wherein the plate engages a skin surface of a patient to resist
said retraction by the soft tissue as second handle urges said
blade to induce retraction.
[0029] According to a preferred embodiment the guide includes a
first end which co operates with the first end of the first handle
and a second end which receives a distal end of the second handle
thereby guiding the second handle into engagement with said
retractor blade.
[0030] In another broad form of a method aspect the present
invention comprises: [0031] a method for retracting soft tissue in
a surgical would during spinal surgery using an assembly
comprising; [0032] a retractor blade having a first distal end and
a second end which engages a support member; [0033] and an
adjustable stop which engages a pressure plate which co operates
with the retractor blade during refraction by applying pressure to
the body of a patient, [0034] the method comprising the steps of;
[0035] taking the retractor blade and attaching it to the support
member; [0036] inserting the retractor blade into a surgical
incision; [0037] adjusting a clamping assembly which co operates
with a retaining member to exert a retraction force on the
retractor blade; [0038] allowing a bearing member to engage a skin
surface of a patient; [0039] manipulating the support member to
induce retraction of the soft tissue against a bearing force
applied by the bearing member opposite to the direction of
retraction.
[0040] The method according to one embodiment comprises the further
step of inserting the retaining member into a sleeve in the support
member prior to engagement with the retractor blade and prior to
insertion of the retractor into the incision.
[0041] In another broad form the present invention comprises:
[0042] an assembly for retracting soft tissue in a surgical wound,
the assembly comprising; [0043] a refractor blade having a first
distal end comprising a blade arm and a proximal end; [0044] a
retaining arm and a clamping assembly which engages the retaining
arm having a first end which is slidably retained by said retention
arm and a second end which receives and retains a pressure plate
assembly; the clamping assembly including means to enable vertical
adjustment to alter the vertical position of the plate assembly
relative to the retaining arm.
[0045] In another broad form the present invention comprises:
[0046] an assembly for retracting soft tissue in a surgical wound,
the assembly comprising; [0047] a retractor blade having a first
distal end comprising a blade arm and a proximal end comprising a
retaining arm; a clamping assembly which engages the retaining arm
having a first end which is slidably retained by said retention arm
and a second end which receives and retains a pressure plate
assembly; the clamping assembly including means to enable fine
clamping adjustment of the pressure plate when the clamping
assembly is set in a selected location along the retaining arm; the
fine adjustment determining the extent of clamping force exerted
between the blade arm and the pressure plate.
[0048] According to a preferred embodiment, the clamping assembly
is adjustable relative to the retention arm thereby enabling
locking adjustment between the clamping assembly and the blade arm.
Preferably, the clamping assembly is telescopically adjustable and
includes openings which receive a locking pin which enable the
clamping assembly to adopt various vertical positions. The plate
assembly allows fine horizontal adjustment according to the
clamping force required. The plate of said plate assembly engages a
skin surface of a patient to provide an opposing force against
retraction of soft tissue to maintain the desired refraction
force.
[0049] In another broad form the present invention comprises:
[0050] an assembly for retracting soft tissue in a surgical wound,
the assembly comprising; [0051] a retractor blade having a first
distal end comprising a blade arm and a proximal end comprising a
retaining arm; a clamping assembly which engages the retaining arm
having a first end which is slidably retained by said retention arm
and a second end which receives and retains a pressure plate
assembly; the clamping assembly including means to enable
horizontal adjustment to selectively alter the distance between the
blade arm and the clamping assembly.
[0052] The present invention provides an alternative to the known
prior art and the shortcomings identified. The foregoing and other
objects and advantages will appear from the description to follow.
In the description reference is made to the accompanying
representations, which forms a part hereof, and in which is shown
by way of illustration specific embodiments in which the invention
may be practiced. These embodiments will be described in sufficient
detail to enable those skilled in the art to practice the
invention, and it is to be understood that other embodiments may be
utilized and that structural changes may be made without departing
from the scope of the invention. In the accompanying illustrations,
like reference characters designate the same or similar parts
throughout the several views. The following detailed description
is, therefore, not to be taken in a limiting sense, and the scope
of the present invention is best defined by the appended
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0053] FIG. 1 shows a perspective view of a retraction assembly
according to one embodiment.
[0054] FIG. 2 shows with corresponding numbering a perspective view
of the assembly of FIG. 1 including a guide member with
trochar.
[0055] FIG. 3 shows an enlarged view of a guide assembly.
[0056] FIG. 4 shows an enlarged view of the plate and sleeve of
FIG. 2.
[0057] FIG. 5 shows the handle in isolation from the assembly of
FIG. 2.
[0058] FIG. 6 shows an elevation view of a retraction assembly
according to an alternative embodiment;
[0059] FIG. 7 shows an end view of the retractor blade of FIG.
6;
[0060] FIG. 8 shows a top view of the retractor blade of FIG.
6;
[0061] FIG. 9 shows an opposite end view of the retractor blade of
FIG. 6.
[0062] FIG. 10 shows a side elevation view of a retractor assembly
according to an alternative embodiment.
[0063] FIG. 11 shows with corresponding numbering a cross sectional
elevation view of the retractor assembly of FIG. 10.
[0064] FIG. 12 shows a top view of the connector engaging support
member.
[0065] FIG. 13 shows the clamping member separated from retaining
arm and rotated 90 degrees.
[0066] FIGS. 14a-e show various configurations of retractor
blades.
[0067] FIG. 15 shows a schematic arrangement of a retractor
assembly in use.
[0068] FIG. 16 shows a cross sectional elevation of a clamping
retractor assembly showing a tooth of a retractor blade engaging an
annulus.
[0069] FIG. 17 shows a surgical incision in the skin of a patient
with retractor blade in use.
[0070] FIG. 18 shows a surgical incision in the skin of a patient
with a G Clamp according to the invention and used in conjunction
with another retractor and offset tool.
[0071] FIG. 19 shows a cross sectional elevation of the arrangement
of FIG. 18 showing a reverse tooth of a retractor blade engaging an
annulus.
DETAILED DESCRIPTION
[0072] The examples referred to herein are illustrative and are not
to be regarded as limiting the scope of the invention. While
various embodiments of the invention have been described herein, it
will be appreciated that these are capable of modification, and
therefore the disclosures herein are not to be construed as
limiting of the precise details set forth, but to avail such
changes and alterations as fall within the purview of the
description.
[0073] FIG. 1 shows a perspective view of a retraction assembly 1
according to one embodiment. Assembly 1 for refracting soft tissue
in a surgical wound comprises a retractor blade 2 having a first
distal end 3 and a second end 4 which includes an associated handle
5. Assembly 1 further comprises a one piece trochar handle 6 having
a pointed tip first end 7 which engages blade 2 and a second end 8
which includes a manual operating control element 9. Intermediate
therebetween is adjustable stop 10 which engages a plate 11,
wherein the plate engages a skin surface of a patient to resist
retraction by the soft tissue. Trochar 6 also includes a locking
nut 12 which co operates with thread 16 and enables locking of the
plate 11 in a particular position for a predetermined extent of
retraction. A washer which is not threaded can be employed as an
alternative to plate 11. Retractor blade 2 has at its proximal end
4 a female recess 17 which receives male profile parts 18 which
prevent rotation of blade 2. External refractor handle 5 has
threaded bolt 25 that secures handle 5 to top surface recess 17 of
blade 2. Square recess 27 to receives guide 13. Handle guide
assembly 13 receives via end 36 sleeve 19, trocar or handle 6.
[0074] FIG. 2 shows with corresponding numbering a perspective view
of the assembly of FIG. 1 Handle 5 includes a formation 27 which co
operates with a guide member 13 (see FIG. 1). The formation 27 is
an opening which receives an end of the guide member 13. According
to one embodiment the second handle trochar 6 in FIG. 1 is replaced
by an alternative handle H which includes at least one threaded
region 34 which co operates with plate 11, adjustable stop and a
locking nut 12. The guide member 13 co operates with the first
handle 5 to enable setting of a refraction state. The assembly 1
allows adjustment of retraction by increasing or decreasing a
retraction force. Plate 11 is preferably threaded for sleeve
19.
[0075] Typically a surgical wound is opened to expose or partially
expose the surgical target. Structures and soft tissues to be
retracted are identified. Refractor blade 2 of assembly 1 as shown
in FIG. 1 is attached to a handle 5 and is inserted through an open
wound and positioned. Threaded trocar 6 is passed through the wall
of a patient's body through a separate wound along a line of a
preferred line of retraction force to be established. The trocar 6
is then screwed into retractor blade 2 with end 7 penetrating
opening 15. Pulling this trocar 6 applies the correct line of
retraction force and thus acts as a second handle. Although a
retraction force may be applied continuously by pulling with the
hand, the retractor 5 can be stabilized at a desired position by
turning nut 12 with washer on proximal part of trocar 6 until stop
plate 11 contacts skin. Washer and nut 12 resists tissue pull on
the handle by pressure on the external body wall. Handle 1 may be
removed from blade 5 or left attached to help further adjustment.
Turning nut 12 can adjust retractor blade 5.
[0076] A more complex arrangement is also envisaged, and described
below using separate trocar 6 with sheath, and guide system 13. As
can be seen in FIG. 1 trochar locates in sheath 19. This employs
some of the following additional elements: [0077] 1. Method and
apparatus for precise positioning of the trocar 6 so that it aligns
with ideal blade position. I.e. Guide. [0078] 2. Large plate 11 and
nut 12 are replaced with other mechanisms that spread muscle force
over body wall. Such mechanism includes a separate plate that a
sleeve engages via threads as shown in FIG. 1. Both envisaged
embodiments of plate and washer variants increase surface area and
are shaped to reduce chances of skin injury. [0079] 3. Sleeves
which pass through body wall may also be employed with trocar
6.
[0080] Purpose of the sleeve [0081] a. By having increased width of
sleeve over trocar 6, this increases resistance to motion in line
of body wall and thus provides a more stable position for the
handle. [0082] b. Such a sleeve 19 may also be attached to plate 11
thereby making plate 11 more stable. [0083] c. By fixation to plate
11, sleeve 19 transmits forces from handle 6 to plate by presence
of large collar 10 which engages nut 12 on handle 6. [0084] d. Such
a sleeve 19 allows trocar 6 to be removed and replaced with a
threaded handle. This avoids having unguarded threads passing
through body wall. [0085] e. Length of sleeve and trocar can be
made so that adjusting nut 12 on trocar 6 or handle limits depth
that trocar or handle can penetrate. [0086] f. Sleeve 19 may be
adjustable relative to plate 11 which controls depth of sleeve 19
within the body.
[0087] FIG. 3 shows an enlarged view of a guide assembly 20
isolated from the retraction assembly with trochar 22 engaged with
end 36. Assembly acts as a positioning guide and comprises an
adjustable frame 21 which acts externally as a guide and a safety
stop for trocar 22 and sleeve (see FIG. 4). Guide assembly allows
correct positioning internally of percutaneous handle 22 by
indicating a finishing position and attitude/direction. Guide 20 is
adjustable, with indicator 23 to indicate distance from external
guide to a safety stop which can be used to set correct length of
trocar and sleeve. External guide assembly 20 can be opened to
allow removal of guide 20 once trocar 22 and sleeve (not shown) is
positioned. FIG. 3 shows frame 20 engages with adjustable member
37. Member 37 engages frame member 21 via sleeve 38 which allows
member 21 to slide relative to member 37. This allows the setting
of a predetermined distance between the member 21 and member 37 so
the surgeon is able to determine the distance of penetration of
handle 22 into a second surgical wound to engage retractor blade 2
(see FIGS. 1 and 2).
[0088] FIG. 4 shows an enlarged exploded view of the plate 11 and
sleeve 19 of FIG. 1. Plate 11 acts as an external Counter force
plate and it will be appreciated that although the shape appearing
in FIGS. 1 and 2 is annular other suitable shapes can be employed.
Also a space frame or other contoured shape can be used as long as
load is distributed evenly against the patient body wall without
injuring skin and to provide maximum stability. A disc could be
used with a threaded opening for sleeve 19 and may include an
additional washer. Sleeve 19 is preferably a threaded tube that
screws through plate 11 to desired depth as referenced from guide
20(see FIGS. 3). Sleeve 19 fits very tightly around trocar 6 of
FIG. 1. Sleeve 19 has a large proximal collar 30 to acts as depth
stop for handle 6. Sleeve 19 is connected to plate 11 and then
inserted through body wall with trocar 6 until plate 11 engages the
body wall. Sleeve 19 portion locates inside muscle and fat provide
some stability. Amount of Sleeve protruding from plate 11 is set to
have minimal overlap over psoas muscle to avoid restricting
movement of the percutaneous handle.
[0089] FIG. 5 shows the trochar handle 6 in isolation from the
assembly of FIG. 1. Trocar 6 has a sharp pointed end 7 sharp
pointed passes through sleeve 19 (see FIG. 1) so that sleeve 19 is
replaced with percutaneous handle 6. Handle 6 includes a proximal
thread 31 for adjustable nut 14 or made so only slightly longer
than sleeve 19 to prevent over penetration and distal end thread 32
to engage blade 2 via opening 15. Handle 6 is inserted through body
wall of a patient and guided by positioning guide 20 with sleeve 19
around it. Sleeve 19 is attached to counterforce plate 11. The
percutaneous handle 6 slides in sleeve 19 and has a proximal knob
33 to enable pulling and to prevent rotation when nut 12 is turned.
This handle 6 is threaded distally (32) to engage blade 2 and
threaded proximally (31) for large adjusting nut 12 to engage
against collar 30 of sleeve 19. As handle 6 is pulled muscle
internally is retracted, large nut is spun on handle until it
engages plate which thus by counterforce on body wall secures
handle in position. More or less retraction is created by turning
or releasing nut 12. Once percutaneous handle 6 is attached to
threaded opening 15 of blade 2, initial open handle 5 can be
retained to provide better and more controlled guidance but once
correctly positioned and secured by tension against counter plate,
open handle 5 may be removed. Handle 5 may be reattached as
required.
[0090] The following describes how the assembly is used while
adopting the guide 13. After wound opening, a guide 13 is
positioned both internal and external to the wound. The external
guide 13 sits against the skin aligning with internal guide 20 (see
FIG. 2) which is positioned internally at desired position of the
end of the sleeve 19. This position should also match with desired
position for the perc handle. Measurements are read from guide 13
and using this as reference, sleeve 19 is now rotated in threaded
opening 21 portion of plate 11 so that sleeve moves in or out
relative to plate 11. Trocar 6 is inserted into sleeve 19 (with
attached plate 11) and trocar 6 and sleeve 19 are then inserted
through opening 22 of external guide 13, through the skin towards
target. Once plate 11 is close to guide member 20, trocar 6 and
sleeve 19 should be well engaged in tissues and preferably visible
internally. External guide 13 is now opened to permit removal of
guide from around sleeve 19. Sleeve 19 and trocar 6 are then
advanced further until plate 11 engages skin and trocar 6 and
needle are visible internally. The trocar 6 is withdrawn and a
threaded handle with its proximal nut is passed through the sleeve
19 and attached to retractor blade 5. Pulling this handle pulls
retractor blade 2 in the correct line of retraction force. This is
handle number two. Although a retraction force may be continued
using hand pressure the retractor 5 can be stabilized by attaching
to plate 11 pressing over a large area of posterior body wall.
Handle 1 may then be removed or left as desired.
Alternative Embodiments.
[0091] 1. Instead of separate trocar and percutaneous handle 6,
these pieces could be Integrated into a 1 piece Trocar/handle which
is threaded distally to engage with internal blade 2 and proximally
for its own nut 12 to engage large washer. This embodiment avoids
the use of a sleeve 19. A washer may have slot, so that drops over
handle 6 after skin insertion, the nut on handle engaging the
washer directly [0092] 2. Instead of threaded nut, rack and pinion
or other mechanisms may be used to apply controlled forces between
percutaneous handle and sleeve collar. [0093] 3. Trocar or
percutaneous handle instead of engaging blade may also engage with
handle 5. [0094] 4. Various mechanism e.g. key mechanism, split
pins, various axle fittings etc may be used to connect percutaneous
handles and blade. The Method of engagement may be varied to suit
requirements of handle e.g. if handle is needed to steer blade
other than simply by pulling, a larger handle maybe inserted
through a larger wound via a series of concentric tubes dilating a
channel through which handle is passed. [0095] 5. Blades can be any
shape or size to suit local anatomy or amount of retraction
required. [0096] 6. Blades of different shape are interchangeable
[0097] 7. Blades have cone shaped opening to allow easy positioning
and engagement of threaded part of handle. [0098] 8. Sleeve and
plate could be one piece with set depth for sleeve [0099] 9. It is
also envisaged that a targeting guide can be employed instead of
having an external guide that opens and closes around handle as
shown. External arm is reversibly fixed to plate. Sleeve is
separate from plate. Thus a hole in the plate determines a correct
alignment. Measurements are taken from a frame about sleeve depth.
Frame is unlocked. Sleeve is screwed to correct depth which will
push the plate away from the body wall. Trocar and sleeve are
inserted through body wall until plate is flush with skin.
Targeting guide is then removed. Various variations of elements are
possible all with same broad intent and principles of action.
[0100] 10. Guide function may be accomplished by incorporation of
sleeve and plate as part of external guide [0101] 11. Varying the
angle of percutaneous handle thru body wall may also impart
downward or upwards force on retractor blade when pulled which
helps direct force of blade as desired. [0102] 12. It is also
envisaged that a percutaneous handle could be used to support an
internal frame or mechanism that in turn supports multiple
retractor blades for e.g. a transpsoas approach. [0103] 13.
Internal frames supporting several blades may also be supported by
percutaneous handle e.g. peritoneal blade clip on like an odontoid
frame. A frame incorporating round bars in order that blades might
rotate is envisaged. Blades might be fixed or hinge about sides of
such frames. [0104] 14. Internal part of the guide may incorporate
handle 1 as shown in FIG. 5 [0105] 15. A series of dilators may be
passed over trocar 6 to create protected passage for insertion of
various handles that include hooks or keying mechanisms for non
threaded engagement with blades. [0106] 16. Methododology. It is
envisaged that handle is passed not only from outside through skin
and into wound but also from wound out of skin, in which case
handles and blades and other parts are attached after tunneling.
[0107] 17. Handles may be straight or curved with bosses and
variations of width with tapers to accommodate external threads and
other mechanisms to engage blades and other parts. [0108] 18.
Retractor blades individual may be round or tubular in various
shapes. [0109] 19. Retractor blades may be individual or as part of
Multibladed retractors inserted individually or as part of assembly
that allows movements of blades. In this embodiment percutaneous
handle or handles attaches to some part of assembly adding to
stability or ability to control. [0110] 20. Multiple percutaneous
handles may be employed. [0111] 21. Percutaneous handle may be
similar to threaded Steinman pin, inserted with power or hand
driver. After insertion, insertion handle or driver may be removed
and detachable handle added with nuts and washers for manual
control and final positioning
Alternative Embodiment
[0112] FIG. 6 shows an elevation view of a retraction assembly 50
according to an alternative embodiment. Assembly 50 according to
the embodiment shown is used for retracting soft tissue in a
surgical wound and comprises a retractor blade 51 having a distal
end 52 and a proximal end 53. Distal end 52 includes a formation 54
which locates inside a patient wound. FIG. 7 shows with
corresponding numbering an end view of the retractor blade 51 of
FIG. 6. Retractor blade 51 has a blade arm 55 which terminates in
distal end 52. Retaining arm 56 terminates in proximal end 53 and
includes openings 57 which allow incremental adjustment and braking
of clamp assembly 58 and finger opening 59 which allows an operator
to pull back on retaining arm 56 to urge blade arm 55 in the
direction of pull. This also allows movement of blade 51 relative
to clamp assembly 58. This assists in setting different retraction
states and forces applied to soft tissue depending upon the
surgical patient requirements.
[0113] FIG. 8 shows a top view of the retractor blade of FIG. 6.
Although blade 51 is shown with blade arm 55 disposed normally to
retaining arm 56, that angle can be varied according to design
requirements and particular applications and orientations of blade
arm 55 required. Clamp assembly 58 is shown engaged to retaining
arm 56 via depending arm 60. Clamp assembly further comprises
adjustable support arm 61. Support arm 61 has a recess 62 which
receives and retains arm 60. Wheel 62 allows adjustment of support
arm 61 relative to depending arm 60. Recess 62 allows travel of arm
61 relative to depending arm 60 thereby enabling the adjustment of
the distance indicated by H between retaining arm 56 and shaft 63
of adjustment handle assembly 64. Arm 60 includes openings 65 which
allow selective adjustment of locking pin 66 so that height H can
be adjusted by moving support arm 61 up or down. Support arm 61 has
at its distal end 67 an opening 68 which receives and retains shaft
63. End 69 of shaft 63 engages pressure plate 70 which includes
outer surface 71 which in use engages the skin of a patient. End 69
as shown is contoured to enable relative movement between plate 70
and shaft 63. This allows the attitude of surface 71 of plate 70 to
adjust to contours of a patient. Plate 70 can rotate about an axis
through shaft 63 and can also tilt relative to that axis.
[0114] FIG. 9 shows an opposite end view of the refractor blade
retaining arm 56 as it engages depending arm 60. Arm 60 includes
recess 72 which receives therein retaining arm 56. In use depending
arm 60 is capable of movement relative to retaining arm 56 thereby
enabling adjustment of the distance between blade arm 55 and
surface 71 of plate 70. Distance I between blade arm 55 and surface
71 of plate 70 is adjustable depending upon the patient. Adjustment
handle 64 urges shaft 63 and plate 70 in the direction of the
patient or away from the patient. The plate 70 engages a skin
surface of a patient to resist retraction forces applied to the
soft tissue. Shaft 63 is according to one embodiment adapted with a
threaded connection which engages distal end of the support arm 61.
Turning handle 73 increases or decreases as required the gripping
force between surface 71 when in engagement with skin of a patient
and the blade arm 55. Since depending arm 60 can be moved and
repositioned along retaining arm 56, this in addition to the
adjustments enabled by adjustment handle assembly 64 accommodates
different distances between the blade arm 55 and plate 70. Also
since clamp assembly 58 allows adjustment of distance H the
assembly 50 has wide scope of both vertical and horizontal
adjustment to accommodate patient differences. Typically a surgical
wound is opened to expose or partially expose the surgical field.
Structures and soft tissues to be refracted are identified.
Retractor blade arm 55 of assembly 50 as shown in FIG. 6 is
inserted through an open wound and positioned. Either before or
after this clamp assembly 58 is attached and adjusted vertically
and horizontally as indicated above. Pulling on opening 59
initially manually applies the required retraction force which is
then locked into position and stabilised by urging plate 70 into
engagement with the patient's skin.
[0115] FIG. 10 shows a side elevation view of a retractor assembly
80 according to an alternative embodiment. Assembly 80 comprises a
first supporting member 81 having a first end 82 and second end 83.
First end 82 engages an adjusting assembly 84 which comprises a
connecting assembly 85. Second end 83 engages a connector 86 which
retains a retractor blade 87. Depending from connecting assembly 85
is retaining arm 88 which retains a height adjustable clamping
member 89. Clamping member 89 is capable of movement relative to
retaining arm 88 and comprises a first end 90 terminating in a
bearing face 91 which opposes retractor blade 87 and a second end
92 which includes an actuating member 93 which enables selective
adjustment of the position of clamping member 89 relative to
retaining arm 87. Connecting assembly 85 includes a runner 94 which
travels along support member 81. Retaining arm 88 engages runner 94
via end 95. Runner 94 further comprises an actuator 96 which
engages support member 81 and contributes to retention of runner 94
in a position selected by a user of the retractor assembly 80.
Actuator 96 is pivotally attached to runner 94 by abutments 97 and
98. Locking knob 99 retains runner 94 against first support member
81 and allows adjustment of the runner 94 relative to supporting
member 81. This allows a user to selectively adjust a distance
between bearing face 91 and retractor blade 87. Support member 81
further comprises an array of teeth 100 which allows incremental
adjustment of connection assembly 85 along support member 81.
Actuator 96 engages corrugations or teeth on a surface of support
member 81. In this case, teeth array 100 is shown on the top of
member 81. Actuator 96 can be arranged to engage teeth on one or
more surfaces. Formations 116 are able to be engaged by actuator 96
to effect incremental adjustment of runner 94. Alternative
formations can be used to effect the incremental adjustment.
[0116] FIG. 11 shows with corresponding numbering a cross sectional
elevation view of the retractor assembly 80 of FIG. 10. Retractor
blade 87 engages connector 86 via end 101. Retractor blade 87 is
fed into a slot 102 located in connector 86. Clamping member 89 is
selectively retained along retention arm 88 via a series of
recesses 117 via locking rod 105. Locking rod 105 including leading
end 106 which engages recess 104 to select the position of clamping
member 89. Actuating member 93 allows locking rod 105 to be
selectively withdrawn from recess 104 and repositioned as required.
Rod 105 is biased to a locking position via spring 107 which urges
rod 105 into engagement with recess 104. To release and move
clamping member 89 requires the user to pull actuating member 93
against biasing spring 107. Retaining arm 88 is retained at end 109
at end 95 of by clamping assembly 85 via locking screw 110. Release
of locking screw 110 allows arm 88 to be released from runner 94
connection assembly 85.
[0117] FIG. 12 shows a top view of the connector 86 engaging
support member 81. Connector 86 retains retractor blade 87 (see
FIG. 10) via slot 102 which and retains support member 81 via
locking pin 103 which engages end 83. Teeth array 100 can be seen
on the top surface of support member 81.
[0118] FIG. 13 shows the clamping member 89 separated from
retaining arm 88 and rotated 90 degrees. From this view opening 111
which retains arm 88 can be seen. The refractor assembly 80 can be
incrementally adjusted both vertically in the direction of arrow
112 and horizontally in the direction of arrow 113. This allows the
assembly to be adjusted to suit retraction geometry for each
particular patient.
[0119] FIGS. 14a-e show various configurations of retractor blades
130, 131, 132, 133 and 134 which can be detachable removed from the
retractor assembly 80. Blade 130 has a distal end 135 which
terminates in an engaging point 136 and a proximal end 137 which
connects to retraction assembly 80. Similarly blades 131, 132, 133
and 134 have respective ends 138, 139, 140 and 141 which engage
refractor assembly 80. It will be appreciated by persons skilled in
the art that there are many retractor blade configurations which
can be connected to the retractor assembly 80 (See FIGS. 10 and
11). In each case the selection of retractor blade size, length,
curvature or geometry can be determined by the surgical
requirements and /or patient anatomy.
[0120] FIG. 15 shows a schematic arrangement of a retractor
assembly 150 in use. Assembly 150 comprises a first supporting
member 151 having a first end 152 and second end 153. First end 152
engages an adjusting assembly 154 which comprises a connecting
assembly 155. Second end 153 engages a connector 156 which retains
a retractor blade 157. Depending from connecting assembly 155 is
retaining arm 158 which retains a height adjustable clamping member
159. Clamping member 159 is capable of movement relative to
retaining arm 158 and comprises a first end 160 terminating in a
bearing face 161 which opposes the patient body and retractor blade
157 and a second end 162 which includes an actuating member 163
which enables selective adjustment of the position of clamping
member 159 relative to retaining arm 157. Connecting assembly 155
includes a runner 164 which travels along support member 151.
Retaining arm 158 engages runner 164 via end 165. Runner 164
further comprises an actuator 166 which engages support member 151
and contributes to retention of runner 164 in a position selected
by a user of the retractor assembly 150. Actuator 166 is pivotally
attached to runner 164 by abutments 167 and 168. Locking screw 169
retains runner 164 against first support member 151 and allows fine
adjustment of the runner 164 relative to supporting member 151.
This allows a user to selectively adjust a distance d between
bearing face 161 and retractor blade 157. The refractor blade 157
resists a force applied to the skin 170 of a patient. Bearing face
161 applies pressure to bearing member 171. Bearing member 171 can
be a plate or softer pliable or elastic material which can gently
transmit compression to the skin.
[0121] Bearing plate 161 or bearing member 171 could be
considerably larger and various shapes to spread clamping force
across larger body surface area to accommodate particular
anatomical requirements e.g. in cervical surgery.
[0122] FIG. 16 shows a cross sectional elevation of a clamping
retractor assembly 180 showing a tooth 210 of blade 187 engaging an
annulus 198. Assembly 180 comprises a supporting member 181 having
a first end 182 and second end 183. First end 182 engages an
adjusting assembly 184 which comprises a connecting assembly 185.
Second end 183 engages a connector 186 which retains a refractor
blade 187. Depending from connecting assembly 185 is retaining arm
188 which retains a height adjustable clamping member 189. Clamping
member 189 is capable of movement relative to retaining arm 188 and
comprises a first end 200 terminating in a bearing face 201 which
opposes the patient body and retractor blade 187 and a second end
202 which includes an actuating member 203 which enables selective
adjustment of the position of clamping member 189 relative to
retaining arm 187. Connecting assembly 185 includes a runner 204
which travels along support member 181. Retaining arm 188 engages
runner 204. Runner 204 further comprises an actuator 206 which
engages support member 181 and contributes to retention of runner
204 in a position selected by a user of the retractor assembly 180.
Locking screw 207 retains runner 204 against first support member
181 and allows adjustment of the runner 204 relative to supporting
member 181. The retractor blade 187 resists a force applied to the
skin 208 of a patient. Bearing face 201 applies pressure to bearing
member 209. Bearing member 209 can be a plate or softer pliable or
elastic material which can gently transmit compression to the skin
208. Retracting blade 187 is curved towards annulus 198. This
geometry increases retraction efficiency and allows the blade 187
and clamp 189 to co operate to balance forces generated for
retraction stabilising the retraction assembly G clamp. Tooth 210
of blade 187 fits into a cut disc space. As the G Clamp blade 187
retracts, the tooth 210 inside the disc space prevents the blade
from lateral motions (i.e. relative to a longitudinal axis of the
disc) and prevents it from lifting up. Since the blade is in the
cut disc space the cut disc annulus limits and prevents the blade
from going too far backwards and over compressing the tissues. The
surgeon is thus able to define how far the retractor will move
backwards by cutting the annulus posteriorly to the desired
posterior limit. The ability to limit and set the amount of
posterior motion by using the cut annulus 198 (which is a tough
structure), is a useful advantage for the surgeon and is enabled by
the G clamp. Retraction can be wound back or wound up using the
ratchet mechanism described earlier but using the cut annulus 198
allows prevention of over compression of tissues. The reverse
angled distal tooth 210 included in blade 187 allows improved
surgical method for refraction. Blade 187 with its reverse angled
distal tooth 210 requires a cut to be made in the annulus 198, the
posterior limit of which is determined by the surgeon. The distal
end of the tooth 210 is engaged into the disc either directly into
the cut annulus 198 or immediately under the cut annulus as shown
in FIG. 15. In use after retracting the blade 157 the posterior
limit of blade retraction is limited by the proximal section of
tooth 188, engaging posterior limit of the cut in the annulus. The
section of distal tooth lying horizontally beneath the posterior
limit of the cut prevents the blade by lifting up or laterally out
of the disc space. This provides increased stability for the
retractor blade 187. One purpose and advantage of the apparatuses
as illustrated in a surgical context is to avoid excessive
retraction of the psoas muscle and potential injury of the lumbar
nerves contained within this muscle. This method of limiting the
amount of retraction by cutting the patient's vertebral disc is
enabled in this case by inserting a tooth 210 of blade 187 to limit
lift retractor blade out. is novel, as is its application using the
assembly shown in FIG. 15. This method and instrumentation has
particular value in an oblique or anterior to psoas approach to the
spine. The assembly shown in use in FIGS. 15,16, and 17(below) is
particularly useful in an anterior to psoas approach to the lumbar
spine. In this approach retraction of psoas by the assembly shown
in FIG. 15, allows disc access by offset instruments to allow an
orthogonal approach to the disc space (particularly L45 and L5/s1
disc spaces) which is desirable. Bony or soft tissue anatomy would
otherwise prevent being truly orthogonal to the disc spaces
essential for maximum safety in this surgery. Refer to FIGS. 18 and
19 below. With conventional systems the bony anatomy of the pelvis
would prevent use of straight instruments being orthogonal to
spine.
[0123] FIG. 17 shows a surgical incision 190 in the skin 191 of a
patient with retractor blade 192 showing blade 192 in use. Blade
192 has a distal end tooth 193 that curves backwards. (see also the
blade 157 in FIG. 15). Blade 192 is retained by support member 194
which has the characteristics of the refractor assembly 150 as
described in FIG. 15. Blade 192 retains tissues 195 and gains its
purchase from a bearing plate (see FIG. 16).
[0124] FIG. 18 shows a surgical incision in the skin 230 of a
patient with a G Clamp 220 according to the invention and used in
conjunction with another retractor 221 and offset tool 222. Blade
223 has a distal end reverse tooth 224 that curves backwards. Blade
223 is retained by support member 225 which has similar operation
and characteristics of the retractor assembly 150 as described in
FIG. 15 so further detailed description of tis operation is not
required. Blade 223 retains tissues 226 and gains its purchase from
a bearing plate 227 (see FIG. 19) associated with clamping assembly
228. In this approach retraction of psoas by the assembly shown
allows disc access by offset instrument 222 to allow an orthogonal
approach to the disc space 229 (particularly L45 and L5/s1 disc
spaces) which is desirable. Bony or soft tissue anatomy would
otherwise prevent being truly orthogonal to the disc spaces
essential for maximum safety in this surgery.
[0125] FIG. 19 shows a cross sectional elevation of the arrangement
of G clamp 220 of figure showing a reverse tooth 224 of retractor
blade 223 engaging an annulus 250. Assembly 220 comprises a
supporting member 231 having a first end 232 and second end 233.
First end 232 engages an adjusting assembly 234 which comprises a
connecting assembly 235. Second end 233 engages a connector 236
which retains retractor blade 223. Retaining arm 238 retains a
height adjustable clamping member 239 which is capable of movement
relative to retaining arm 238. Bearing face 240 opposes patient
body 230 and retractor blade 223 and includes an actuating member
241 which enables selective adjustment of the position of clamping
assembly 228 relative to retaining arm 238. A runner 243 which
travels along support member 231 comprises an actuator 244 which
engages support member 231 and contributes to retention of runner
243 in a position selected by a user of the retractor assembly 220.
Tooth 224 of blade 223 fits into a cut disc space. As the G Clamp
blade 223 retracts, the tooth 224 inside the disc space prevents
the blade from lateral motions (i.e. relative to a longitudinal
axis of the disc) and prevents it from lifting up. Since the blade
is in the cut disc space the cut disc annulus limits and prevents
the blade from going too far backwards and over compressing the
tissues. The surgeon is thus able to define how far the retractor
will move backwards by cutting the annulus 250 posteriorly to the
desired posterior limit. Retraction can be wound back or wound up
using the ratchet mechanism described earlier but using the cut
annulus allows prevention of over compression of tissues.
[0126] Other Applications for Percutaneous Retractor Handle
Technology
[0127] Another spinal operation, where retraction of muscles is
difficult is for lumbar pedicle screw insertion. This is difficult
because of the force required to get the correct line of entry for
screw insertion tools from a conventional midline approach. Strong
retraction is required and this has led to very strong devices
which may easily injure muscles. Attempts to improve efficiency by
using metal retractors which lever off the bone may injure the
bone, facet joints or fracture the transverse process. A
percutaneous handle would help stabilize and avoid such a need.
[0128] Another circumstance where retractor stability is an issue
is when using tubular retractors inserted as a series of increasing
size tubes. These often require table fixation to stabilize as
direction of entry may be displace by tissue forces. Table mounting
is often required to stabilize. A percutaneous handle would help
stabilize and avoid such a need.
[0129] A further circumstance where retractor stability is an issue
is when using multi bladed retractors that are inserted as part of
an assembly and then inserted within the wound. Opening retractor
may move retractor from desired position and often requires the
addition of a table mounted arm. An alternate method of stabilizing
will be to add percutaneous handle to a. Handle is stable in body
wall but this stability can be further increased by addition of
counterforce plate which may compress body wall against sides of
retractor. Percutaneous handles may also be employed in other forms
of surgery e.g. gynaecological or pelvic surgery where approach is
via body cavity but application of retractor force would be
helpful.
[0130] It will be recognised by persons skilled in the art that
numerous variations and modifications may be made to the invention
broadly described herein without departing from the overall spirit
and scope of the invention.
* * * * *