Distraction and retraction assemblies
An assembly (40) allowing retraction of soft tissue away from a reference plane; the assembly including at least one retracting element (51) each comprising a distal end having a formation allowing anchorage of the at least one retracting element (51). The assembly also includes a proximal end (50) of the at least one retracting element capable of movement through at least one degree of freedom relative to said anchorage.
The present invention relates to distraction and retraction assemblies. The invention further relates to an improved apparatus for soft tissue retraction in applications including surgery including, but not limited to spinal surgery. The invention also provides an assembly which performs the functions of distraction and retraction optimising mechanical advantage and efficiency in retraction and resisting unwanted pull out of retractors.
PRIOR ARTThere are in existence a number of assemblies used in retraction of tissues to facilitate spinal and particularly cervical surgery.
The most commonly performed anterior cervical procedure is an intervertebral fusion procedure that typically involve the steps of removing a portion or all of the affected disc material, spreading apart adjacent vertebrae with a distractor, and inserting an implant bone or cage or prosthetic disc into the space previously occupied by the removed disc material. This procedure can be done either from the front of the patient (anterior interbody fusion) or in the lumbar spine from the back (posterior interbody fusion). If done from the front, it is important to reduce the size of the retraction forces applied by the blades of the of the retractor so that the procedure is as minimally invasive as possible and thus minimally interferes with and minimally traumatizes the organs, tissues and vasculature being displaced to allow access to the vertebral region being treated. Posterior surgery can utilize larger tools since the insertion space is more accommodating and posterior structures requiring retraction i.e. muscles are less sensitive.
By way of an example of a known device, U.S. Pat. No. 6,669,699 discloses a Distraction instrument for use in anterior cervical fixation surgery. An intervertebral distraction tool has a clamshell head with upper and lower halves, each having a curved outer surface and a flat inner surface. The distal side of the head is hinged so that the head opens and closes from the proximal side of the head. The hinge is a separating hinge that allows the halves to not only angulate with respect to one another about the hinge axis, but also to vertically separate from one another at the hinge. The distraction separator has decreasing taper at its distal end and a longitudinal bore that accommodates the elongate shaft of the trial so that the separator can be moved longitudinally relative to the shaft. Upon forward movement of the separator, the tapered upper and lower surfaces engage the flat inner surfaces of the head, causing the halves to angulate about the hinge axis of the [head, thereby opening the head.
In another example U.S. Pat. No. 6,743,231 discloses temporary spinal fixation apparatuses and methods for temporarily fixing the relative position of spinal implant assemblies until a permanent fixation position is determined. The disclosed apparatuses and methods enhance the ease of placement of spinal implant assemblies and facilitates the accuracy of positioning of the spinal vertebrae. This apparatus can reduce the number of steps needed to perform spinal surgery and can decrease the likelihood of post-operative complications.
In another example U.S. Pat. No. 6,017,342 discloses a compression and distraction instrument having two pivotally connected handles. Jaw portions engage objects, such as human bone, for purposes of manouvering. A control screw connects with the handles, through a mechanical advantage arrangement, and the screw pivots the jaw portions for the engagement of the objects. There is an anti-friction connection between the screw and the handles, for accurate and precise movement of the jaws. In one embodiment, the screw is axial of the instrument, and, in the other embodiment, the screw is transverse thereto, both have mechanical advantage.
In another example U.S. Pat. No. 6,712,325 of Mar. 30, 2004 discloses a spinal disc space distracter for separating adjacent elements, such as vertebrae. The distracter preferably has a scissors-type distracting mechanism, either in a simple scissors or double-acting scissors configuration. The distracter includes blades that are removable from the jaws of the distracter such that different blades may be used depending on the patient and situation with which the distracter is to be used. The jaws include a mating fixture and the blades include a mating portion for removable association with the mating fixture. In accordance with the principles of the invention disclosed, a spinal disc distracter is provided to allow for an implant insertion technique to be performed during distraction of the disc space. The implants are slid into the disc space between the distracter blades, preferably while the blades are in contact with the upper and lower surfaces of the adjacent vertebral bodies. The distracter is formed to be as minimally invasive and atraumatic as possible such that it may readily be used in an anterior or anterolateral approach. Thus, the distracter is configured to be used in the confined spaces of the human anatomy through a small surgical incision. This distracter has a scissor-like configuration with a pair of handles pivotally connected together. A distracter jaw is coupled to a distal end of each handle such that movement of the handles together draws the jaws apart to separate the vertebrae being treated. The jaws and handles are pivotally coupled together in a double-acting scissor-like configuration to further reduce the space required to move the jaws apart and thus further minimize the invasiveness of the device and procedure. Although the handles, jaws, and distracter mechanism may all lie in the same plane, in order to facilitate visualization of the treatment site during distraction and insertion of an implant, at least the handles may be angled away from the plane of the distracter jaws.
A locking mechanism preferably is provided adjacent to or in the handle to maintain distraction. The locking mechanism may include a spindle or threaded bolt mounted on a first handle and passing through the second handle. An internally threaded speed nut is rotatably mounted on the threaded bolt such that movement of the speed nut along the bolt selectively inhibits movement of the second handle away [from the first handle and thus maintains the vertebrae at the desired distracted [position.
The blades of the distracter are configured to increase versatility of the distracter and are removably coupled to the distracter jaws. Thus, the blades may be changed, as necessary or desired, for a given procedure or patient.
In another embodiment, the blades of the distracter are gradually curved to be out of the plane of the distracter mechanism. Because of the gradual curve, the distal end of the jaws may safely be manipulated through the patient's body with as minimal contact as possible with organs and vasculature including major blood vessels. Moreover, such curvature permits insertion through a smaller incision because of the increased manipulability of the gradually curved blades through small openings and spaces.
In another example of a distracter assembly U.S. Pat. No. 6,740,119 May 25, 2004 discloses a method of distracting vertebral bones to their proper anatomical spacing including sequentially inserting and removing a series of progressively wider cylindrical spacer elements into the intervertebral space between adjacent vertebral bones until the distance between the vertebral bones is anatomically appropriate
There are limitations inherent in conventional self retaining retractors used widely in surgery and routinely in anterior spinal surgery. These typically have two blades typically with teeth at one end that are linked by a hinge to scissor type handles. The teeth grip into or under the tissues and apply lateral forces as the handles are compressed by the surgeon to produce the desired exposure. The teeth grip and retract both sides of a wound against each other with equal distribution of retraction force. This means that when retracting two sides with different resistances eg left and right sides of an anterior (front) cervical wound (trachea, larynx, ET tube, oesophagus and thyroid are on one side only) excessive forces and retraction are applied to the easy side in an effort to retract the opposite more resistant side. This is one reason why conventional retractors slip, twist and rise up. Placing the teeth of these retractors under the longus colli muscle (next to the spine) works to an extent and is the standard method by which retractors in the anterior (front) of the neck are secured but it is common for retractors to require repositioning several times during an operation in addition to the difficulty of securing them in the correct place initially. Teeth cannot be made too sharp or too long as they will damage vital structures The second reason they slip is because the retraction forces are coming from the top ie outside the wound at a distance to where they at required at the bottom of the wound. The path of least resistance is up and as the retractor opens even the slight bending tends to produce a vector of force up as the blade follows the path of least resistance out of the wound leading to unwanted displacement of the retractor and therefore compromised retraction. The third reason they slip is that the tissues under retraction stretch reducing their counter force. As self retaining retractors rely on counter force for stability as this is reduced loosening inevitably occurs.
Repeated adjustment can and does produce unnecessary tissue injury e.g. swallowing problems or hoarseness of voice in perhaps 5-10% of anterior cervical operations. It also wastes time and produces unnecessary bleeding. Persons skilled in the art are aware that one of the most frustrating parts of this type of surgery is positioning and maintaining position of the retractors. Conventional retractors are sometimes weighed down with chains and weights to resist the unwanted upwards rotational forces.
Some known retractor blades have short spikes for bony fixation that create a point of leverage allowing limited movement of the blade. Other retractor systems allow for fixing a retractor blade to bone within a wound via pins or screws. Some known retractor systems allow rotation of a retractor blade around an axis of rotation attached to a frame that is outside the wound e.g. Synframe™ from Synthes™.
Hohmans™ and Taylor™ retractors have an integral point that is either hammered into bone or pushed into a position to provide bone fixation leverage. These are widely used in orthopaedic surgery. A Taylor™ type retractor blade is known which incorporates a tube for a securing pin. Also known are lever type retractors such as a hip retractor system designed by Dr R Barry Sorrells. Also know is a rail system for retractor blades and a blade that has means for fixation to bone with screws. Also known is a hip retractor system designed by a Dr S David Stulberg using only pins that are either drilled or hammered into the bone. Some of these can bend or lever slightly but allow no true rotation. External frames for securing levered retractors are also known. For example an assistant (surgeon) free self-retaining hip surgery retractor designed by Dr S David Stulberg is known.
If hammered into bone via a short point fixation, then multiple rotations produces loosening and unwanted withdrawal. Where the pins rest on their point as a simple point of leverage but without deep fixation then they are prone to slippage if knocked or an assistant surgeon is not concentrating. Accordingly, a major disadvantage of the prior art is that there are no retraction systems in use that allow free rotation without compromising fixation.
An anterior cervical system is known whereby retraction blades for cranial and caudal (top and bottom) part of wound are slid over known distraction pins. Additional lateral (side to side ) retractors are still required and unconnected. These blades are loose and can rotate only about axis of pin, (which is not very useful) and are not adjustable. They provide no lateral retraction parallel to spine which is a much greater problem and which is addressed only in the present invention to be described below.
The Prodisc™ anterior cervical system for cervical disc replacement has distraction screws with distraction arms that slide down over screws. The Prodisc™ uses a screw cap at top that secures the distraction arm, with downward pressure on to the base of the screw.
INVENTIONThe present invention in one form provides improvements in distraction and retraction assemblies. The invention further provides an improved apparatus for soft tissue retraction in applications including surgery and including, but not limited to spinal surgery and which ameliorates the aforesaid disadvantages of the known retractors. The invention also provides an assembly which performs the functions of distraction and retraction optimising mechanical advantage and efficiency in retraction and resisting unwanted pull out of retractors. More particularly, the invention provides an assembly allowing secure anchorage of retractors and also longitudinal and rotational adjustment of the retractors to adjust retraction forces.
The invention further relates to an assembly which performs the aforesaid retraction functions in conjunction with applied distraction of vertebrae using distraction pins and co operating sleeves so that mechanical advantage in both distraction and retraction is achieved optimising efficiency in retraction and resisting unwanted pull out of retractors.
Although the invention will be described with reference to its surgical applications it will be recognised by persons skilled in the art that the invention has wider applications in retraction alone and in combination retractions and distraction.
During a surgical operation retractors are used to facilitate access to tissues. The present invention employs in one form the principle of fixation into bone (either directly or indirectly) to provide a secure anchorage and base for a retractor blade and also a stable axis for rotation of the blade within the wound without the prior art unwanted dislocations .
The invention improves tissue exposure and surgical site access and minimizes soft tissue injury, bruising etc (due to the more controlled and reduced movements against tissues) whilst allowing variable selective rotation of at least one retractor blade as required during the surgical procedure. The combined features of the ability to adjust retraction pressure and reduce tissue pressure applied by the retractors thus minimizing tissue injury while maintaining stability of the blade distinguishes the present invention from the known prior art. The direct or indirect fixation (anchorage ) to bone of a retractor prevents unwanted slippage and avoids the need for readjustment apart from the selected amount of rotation. The stable axis of rotation from within a surgical wound also imparts a mechanical advantage to retraction pressure reducing operator fatigue. Bone fixation with rotation is achieved in a number of different ways allowing application in numerous anatomical situations.
In each of the embodiments to be described below including the direct fixation retractor assembly and the indirectly anchored retractor and distraction assemblies there exist the following common features:
-
- 1 A means for fixation to bone
- 2. A connection between the point of fixation and retractor (a link)
- 3. A means for retraction of tissues (a blade)
- 4. A mechanism for variable rotation dictated by direct or indirect fixation of the blade to bone.
The fixation to bone, link, blade and means of rotation may be direct retractor engagement such as that described with reference to
This invention in all its forms has application whenever bone fixation is available principally in spinal and orthopaedic surgery but also other surgical disciplines.
It is, another object of the present invention to provide an improved tissue retraction assembly for retracting wound margins and which provides optimal anchorage of side arms, load application to tissue, rotational and longitudinal adjustment and which may be used in conjunction with vertebral distraction pins.
It is further an object of the present invention to provide an assembly that efficiently and simply manages the insertion of a distractor and retractor. Other objects of the present invention not explicitly stated will be set forth and will be more clearly understood in conjunction with the descriptions of the preferred embodiments disclosed hereafter.
In its broadest form the present invention comprises:
an assembly for combined retraction of wound margins of soft tissue and distraction of vertebrae; the assembly including;
a pair of pins anchored in said vertebrae;
sleeves concentrically engaging said pins;
means to apply a distraction force to said pins via said sleeves;
a first side arm having a first end including a recess capable of engaging one said pins and a second end including connection means which releasably receives a first retractor arm via a mating profile;
a second side arm having a first end including a recess capable of engaging the other of said pins and a second end including connection means which releasably receives a second retractor arm via a mating profile; wherein said respective connection means each allow rotatable adjustment of each said retractor arms to retract said soft tissue margins.
In another broad form the present invention comprises:
an assembly for retraction of wound margins of soft tissue, the assembly including;
a first side arm having a first end including a recess capable of engaging a pin anchored in a vertebrae, and a second end including connection means which releasably receives a first retractor arm via a mating profile;
a second side arm having a first end including a recess capable of engaging a second pin and a second end including connection means which releasably receives a second retractor arm via a mating profile; wherein said respective connection means each allow rotatable adjustment of each said retractor arms to retract said soft tissue margins.
According to a preferred embodiment, sleeves concentrically engaging said pins; the assembly further comprising means to apply a distraction force to said pins via said sleeves;
In another broad form the present invention comprises:
an assembly allowing distraction of adjacent vertebrae and retraction of soft tissue; the assembly comprising; means to apply a distraction load to said vertebrae via pins fixed to each vertebrae; the assembly further including;
a first side arm having a first end including a recess capable of engaging a first said pins anchored in a vertebrae, and a second end including connection means which releasably receives a first retractor arm via a mating profile;
a second side arm having a first end including a recess capable of engaging a second of said pins and a second end including connection means which releasably receives a second retractor arm via a mating profile; wherein said respective connection means each allow rotatable adjustment of each said retractor arms for adjustment of a retraction force applied to said soft tissue margins.
In another broad form the present invention comprises:
an assembly allowing distraction of at least one vertebrae and retraction of soft tissue; the assembly comprising;
means to apply a distraction load to said vertebrae via first and second distraction pins,
a first retractor comprising a first side arm having a first end including a recess capable of engaging a first said pins anchored in a vertebrae, and a second end including connection means which releasably receives a first retractor arm via a mating profile;
a second retractor having a second side arm having a first end including a recess capable of engaging a second of said pins and a second end including connection means which releasably receives a second retractor arm via a mating profile; wherein said respective connection means each allow rotatable adjustment of each said retractor arms for adjustment of a retraction force applied to said soft tissue margins.
In another broadest form the present invention comprises:
a retraction assembly for retracting soft tissue the assembly comprising;
a first set of jaws defining a recess for receiving therein a first pin attached to a first vertebrae and including an arm which receives and retains thereon a first retractor capable of rotation about said arm;
a second set of jaws defining a recess for receiving therein a second pin attached to a second vertebrae and including an arm which receives thereon a second retractor capable of rotation about said arm.
In another broad form the present invention comprises:
a retraction assembly comprising
a first member including a first arm having a set of jaws defining a recess;
a second arm extending from the first member;
the second arm having means to receive and releasably retain a first retractor;
a second member including a first arm having a set of jaws defining a recess;
a second arm extending from the second member;
the second arm on said second member having means to receive and releasably retain a second retractor;
wherein, when the recess of said first member engages a first pin and the recess of said second member engages a second pin each said first and second retractors, retract wound margins in soft tissue; wherein each said retractors are rotationally adjustable relative to respective said second arms of said first and second members.
In another broad form the present invention comprises:
a retractor assembly for retracting wound margins the assembly comprising;
a first retraction member having a first end which includes a recess for engaging a distracter pin inserted in a vertebrae,
a second member integral with said first retraction member and including a free end comprising a first retractor blade for retracting one said wound margins;
a second retraction member having a first end which includes a recess for engaging distracter pins inserted in a vertebrae,
a second member integral with said second retraction member and including a free end comprising a second retractor blade for retracting a second of said wound margins.
In another broad form the present invention comprises:
a distraction and retraction assembly comprising;
first and second distraction pins;
sleeve members adapted to concentrically engage said pins for transmission of a distraction force on each pin;
first and second retraction members; said first retraction member having a first arm having a set of jaws defining a recess which engages one said pins and a second arm extending from the first member;
said second arm comprising a blade capable of retraction of soft tissue;
said second retraction member including a first arm having a set of jaws defining a recess engaging a second one of said pins and a second arm extending from the second member; said second arm of said second retraction member comprising a blade capable of retraction of soft tissue;
wherein, each said first and second arms engage via mating formations which allow lateral and rotational adjustment of each said first and second retractors.
According to a preferred embodiment each said set of jaws are disposed in a common plane and engage the pins anchored in vertebrae.
According to one embodiment said jaws are disposed in an orientation which is normal to a longitudinal axis of said first and second arms. According to one embodiment, each said arms include spline formations which engage with corresponding formations on respective first and second retractors.
According to a preferred embodiment the spline formations on each said arms provide a mating engagement which allows longitudinal and rotational adjustment of said arms.
According to a preferred embodiment each said blades include openings which receive and retain a tool adapted for adjustment of the orientation of said blades.
The present invention will now be described in more detail according to a preferred embodiment but non limiting embodiment and with reference to the accompanying illustrations.
Typically according to one method, cervical distraction of vertebrae involves the use of pins temporarily fixed to the vertebrae to be distracted. Generally two pins are used one above and one below a disc or vertebral body of interest. Traditionally in a Caspar system these pins have only been used for distraction purposes via sliding tubes that fit axially over the pins and connect to an associated distraction mechanism. According to one aspect the role of the pin has been expanded to perform one or more of the following roles. The pin acts as x-ray marker to estimate a midline of a spine for cage or prosthetic disc replacement. The known and commonly used Caspar type distracter is then secured to the spine. There is however known use of distracter tubes that each slide over respective pins and which is secured to the pins via a screw applied at a threaded region. This however, does not have snug hex or square fit at a base of the pin but is round and transfers distraction forces along a length of a round pin. This does not provide optimal load transfer to the spinal vertebrae where distraction is required but rather applies the load at a moment arm distant from the required load application site. The known technique for distraction force application applies a bending and shear force to the pins which must be transferred down the pin to its point of engagement with the vertebrae. A mechanical advantage during distraction is provided the closer the load is applied to the vertebrae due to a reduced moment arm and elimination of a bending moment on the pins so it is desirable to provide an assembly which meets this objective. Accordingly, according to the invention a shear force is applied at a base of pins to be distracted.
Throughout the specification a reference to a retractor arm may be taken to be synonymous with side arms, retractor blade and retraction member. A reference to blades will be taken to include a reference to retractors or retractor arms
To fully appreciate the various embodiments of the invention to be described below a summary of the bone fixation methodology and associated apparatuses and assemblies.
1. Bone Fixation 1. Single Point Bone FixationThis may be accomplished by screws or short spikes or a spike/screw combination. Spikes are useful where a line of pull is oblique to a line of insertion and where anatomy is unfavorable for screws. Multiples screws or spikes may be used. A portion of the screw or spike may engage and link to other components. This portion is referred to as the anchor.
Anchor recess shapes which may be used (see drawing/s) include the following non limiting embodiments:
- 1. Mushroom (conical with enlarged point)
- 2. Cone
- 3. dimple
- 4. cup for blade
- 5. pedestal
- 6. Integral hinge and sidearm for connection to blade
- 7. Integral hinge allowing rotation in single plane
- 8. Integral small ball and socket with shaft for connection to blade.
2 Two Point Fixation with Gripping Devices- b. penetrating with 2 conical points (see
FIG. 1 below) - c. non penetrating i.e. other clamping device with flat or curved face.
- b. penetrating with 2 conical points (see
-
- a. Anchor and blade and means of rotation are integral in one piece as shown below in
FIG. 1 . - b. Anchor incorporates means of rotation
- i. anchor with built in rotating shaft for blade attachment that allows rotation in 1 plane only.
- ii. Anchor with built in ball and socket plus shaft for blade fixation that allows rotation in multiple planes.
- c. Anchor /blade interconnect directly e.g. dimple, mushroom, cone, cup, (see
FIGS. 47 , 28, 37 and 44) - d. Link blade interface allows rotation either with integral or detachable hinge see
FIGS. 21 , 31 , 33, 35 or as in. anterior cx systemFIG. 20 .
- a. Anchor and blade and means of rotation are integral in one piece as shown below in
-
- It will be noted that the various combinations of component include methods for securing components together:
- a. That may permit desired free rotation but may limit movement in other planes likely to produce loosening or fall out.
- It will be obvious to those skilled in the field that the mechanisms shown limiting unwanted motion are additions and more simple versions of the following components with less stability are easily envisaged.
- flathead (FIGS. 43,44,45,46) which prevents lift out once rotated and restricts side to side movement
- modified cup with top loading and side loading blade with key lock feature (
FIG. 27 , 28, 29) prevents lift out and side to side movement and limits rotation. - modified cottage loaf (
FIGS. 37 and 38 ) and tunnel blade (FIG. 37 ) prevents lift out and side to side movement - b. That lock rotation at the desired point e.g.
- splines on sidearm and blade in anterior cx system (FIG. nos 20, 40-42).
- Flathead with recess for locking pin. Once retractor blade rotates to certain angle e.g. 30 degrees recess is exposed allowing pin to be inserted from above down front of the blade. This pin is easily pulled out allowing free rotation of the blade but by insertion prevents blade returning until pin removed. Locking the retractor blade in this fashion means external handles for the blades or weights to pull the blade outwards are avoided. This reduces number of instruments around operative field, frees or avoids totally the need for an assistant and facilitates x-rays. (FIG. no 43-45)
- c. There are known mechanism for “clicking” in that could be used to join blades from above onto secured anchors in situ. A retractor blade might thus click into position from above which is easier than sliding components together but once together resist pull out directly unless slid out sideways.”
- modified cup with top loading and side loading blade with key lock feature (
- It will be noted that the various combinations of component include methods for securing components together:
Referring to
Scissor member 2 terminates in a formation 14 comprising a recess 15 having therein a conical jaw 16. Jaws 13 and 16 preferably lie along a common axis and are disposed in opposing relationship. Alternatively, jaws 13 and 16 may be disposed on parallel axes. Jaws 13 and 16 are conical each terminating in a sharp point adapted for engagement directly into bone or with an anchorage enabling rotation of assembly 1 about axis 17 in a rotational direction shown by arrow 18.
Referring to
Referring to
Referring to
Arm 112 further comprises blade region 112a which terminates in a formation 142 which defines a recess 143 which receives and retains therein joining arm 144 of joining member 114. This allows arm 112 to selectively rotate about joining arm 144. Joining member 114 also comprises a bifurcated portion 145 having two arms which define recess 146 which receives and retains anchorage assembly 116. Anchorage assembly 116 comprises an anchorage pin 147 having a leading end 148 terminating in a sharp point 149 to facilitate penetration in bone and a trailing end 150 providing a driving member 151 to facilitate compression of 152 against 145 securing joining member 114. Pin 147 is housed in guide sleeve 152 which engages bifurcated portion 145. Guide sleeve 152 has connected thereto an ancillary sleeve 153 which receives in recess 154 a tool (not shown ) to facilitate distraction of anchorage assemblies 116 and 115 along an axis parallel to the axes of rotation of arms 111 and 112. The sleeves 152 and 139 engage onto square portions of respective pins. The bifurcated elements 133 and 145 also engage snugly around square portions of pins 135 and 147. This connection prevents independent rotation of elements. Combined rotation of all elements is prevented by joining two sleeves and pins together with an external distraction assembly. This distraction assembly (not shown) may join with the assembly as shown via recess 154 and 158 or may be integral as in existing Caspar systems.
With the above described assembly 110 a surgeon may selectively effect both distraction (of bone) and retraction (of soft tissues). The assembly allows distraction along an axis parallel to the axes of rotation of arms 111 and 112 and selective opposing rotational adjustments of arms 111 and 112 and if required removal of one or other of arms 111 and 112.
These variations permit attachment of retractor blades close to where required allowing secure fixation and rotation. Variations depending on anatomy are required but the principle remains the same: namely, that a secure axis of rotation is achieved from within a surgical wound. Components can be separated and assembled prior to insertion by the scrub nurse or inserted separately and joined in situ. Disassembly facilitates cleaning, sterilisation and replacement of components. Various materials in medical usage for fabrication are envisaged.
According to an alternative embodiment, the retraction assembly uses a single pin as a point of fixation for retractor blades but without a second pin. This would utilize a single tube not connected to distracter mechanism for surgeons not wishing or able to use distraction.
A retraction arm also described as a side arm co operates with a blade portion to perform retraction of soft tissue wound margins.
Joining members which engage retractor blades (also referred to in the art as side arms) may be flat in one plane or with a bend so that part lies in one plane and another part in another plane allowing rods to sit a few mms below the plane assumed by the jaws of the bifurcated elements to fit a natural contour of a spine.
Flat members of the type shown in
Side arms allow rotation while maintaining a strong join to avoid disconnection and maintaining point of fixation of retractor blades down on a spine where required. Male/female connection with rod on joining member/side arm and tube on retraction arms at the base of retraction blades is preferred. Splines (see
A tendency of the retractor blade and retractor joining member side arm to rotate pins is resisted by dual tubes which once fitted, will prevent independent movement of screws, side arms and blades.
According to one embodiment splines are used to make the engagement between the retractor arms and retractor blades but this is a non limiting engagement arrangement and it will be appreciated by persons skilled in the art that other forms of engagement which preferably accommodate axial release and locking and also selective rotation may be employed. For example, a ratchet mechanism may be used. The retraction blades are drawn according to one embodiment, with splines but this is to be taken as a non limiting arrangement. Not all combinations of flat or offset, open or closed, with or without splines adjustable or non adjustable are shown. Numerous shapes are envisaged to accommodate different areas of the spine (and other parts of the body e.g. in non spinal orthopaedics.)
Referring to
In an alternative embodiment it will be appreciated that position of spline on shaft 268 may be varied to opposite end 265 with a corresponding change of mating profile to other end of recess 271 and in a further embodiment blade could contain splines and the shaft the recesses.’ Opposite gender spline mating may also be employed.
The number of splines and teeth angles may be varied according to requirements. In an example of a method of use of the assembly, a surgeon may assemble the combined distracter and retractor assembly of
The degree of retraction is set by engaging the splines at a predetermined position so as to set the retractor arms 111 and 112 at an angle of repose which keeps soft tissue margins apart as required by the surgeon. If the aforesaid description relates to a right side distracter arm and retractor blade assembly there will be a corresponding left hand side arrangement which is preferably symmetrical about a transverse line through a disc space. If the aforesaid description relates to a left side distracter arm and retractor blade there will be a corresponding right hand side arrangement which is again symmetrical about a transverse line through the disc space. The distraction forces are applied at the base of the pins 136 and 147 to optimise mechanical advantage and to eliminate pin bending loads. This assembly described above allows variable distraction poses and movement without removal of retractors—side retractor arms and blades.
According to one aspect of the invention once the retractor blades are inserted they are fixed at or adjacent to a location where a tip of an end of the Retractor blade is required. This is usually deep in the wound and generally involves firm fixation to an adjacent bony surface via a screw, clamp or other gripping device that connects directly to the blade or via an intermediary linkage.
In most situations this connection with the fixation device will allow rotation of the blade about the point of fixation, either because the point of fixation itself can rotate, e.g. semicircular spikes forming a pincer or via an intermediary linkage which allows the rotation while remaining in fixation as in the cervical assembly described in detail. This fixation with rotation allows retractor blades to be left in situ throughout a procedure but allowing the surgeon to release the pressure and the retraction forces while working on another area thus reducing the tissue trauma but without having to remove the retractor blade or reposition the retractor blade. Releasing self retaining retractors leads to repeated tissue trauma every time these are reinserted and/or reopened. This system would therefore reduce tissue trauma and save time. It would also mean that the retractor once appropriately inserted can be secured in situ and not become loose or dislodged and require repositioning. The fixation device described in the cervical assembly utilises a pin with a screw thread into the bone and is first embodiment of this principal.
An alternative embodiment such as that described in
It will be appreciated by those skilled in the art that the utilisation of this principal could be used in numerous other applications adapting to the different anatomy and retraction requirements throughout the spine, musculoskeletal system or wherever bony fixation can be utilised, e.g. the head.
It will be further recognised by persons skilled in the art that numerous variations and modifications may be made to the invention without departing from the overall spirit and scope of the invention broadly described herein. Such modifications would allow adaptation of key concepts (which is that retractor blades are fixed at or close to critical point of retraction and may rotate) to provide additional retraction devices for use in anterior or posterior spinal surgery throughout length of spine or in orthopaedics or other surgical disciplines where bony fixation is available.
Claims
1. An assembly capable of retraction of soft tissue during surgical procedures, the assembly comprising:
- an anchorage for engaging bone and which anchors the assembly to enable said tissue retraction;
- at least one retracting arm having a first free end and a second end, the second end including a formation which allows the at least one retractor arm to be detachably retained by said anchorage; said retention by the anchorage enabling said at least one retractor arm capable of movement through at least one degree of freedom relative to said anchorage.
2. An assembly according to claim 2 wherein the at least one retracting arm is rotatable about an axis through said second end.
3. An assembly according to claim 2 wherein said anchorage includes at least one anchorage element.
4. An assembly according to claim 3 wherein said anchorage includes two anchorage elements each having formations to anchor the assembly to said bone.
5. An assembly according to claim 4 further comprising a frame assembly including at least one retaining member which receives said second end of each said retracting arms.
6. An assembly according to claim 5 wherein the retaining member provides an axis of rotation for said retracting arms.
7. An assembly according to claim 6 wherein the frame assembly includes at least one opening enabling screw fixation of the assembly to bone.
8. An assembly according to claim 7 wherein the frame assembly includes two retention arms which receive respective opposing retraction members.
9. An assembly according to claim 8 wherein, the frame assembly further comprises a bridge joining the retention arms.
10. An assembly according to claim 9 wherein each retractor arm engages a corresponding formation on the second end of the retractor arms, allowing the retractor arms to rotate about the retention arm and slide therealong.
11. An assembly according to claim 10 wherein each said retention arms have a first end attached to said bridge and a second free end.
12. An assembly according to claim 11 wherein the frame assembly is generally U shaped such that the first and second arms are parallel and disposed normally to the bridge member.
13. An assembly according to claim 12 wherein, the formation on each said retractor arm is a recess which at least partially receives therein at least part of one said arms.
14. An assembly according to claim 13 wherein the recess engages the arm allowing the retractor to undergo said rotation and sliding therealong.
15. An assembly according to 14 claim wherein the frame assembly has a secondary bridge including openings to allow engagement with said free ends of said retention arms.
16. An assembly according to claim 15 wherein the first and secondary bridges each include an opening to allow penetration of an anchorage element for fixation of the assembly to bone.
17. An assembly according to claim 16 wherein, the retraction arms rotate in a direction normal to a longitudinal axis of said retention members.
18. An assembly according to claim 17 wherein, said retraction arms include a gripping region on said retractors which receive a member which facilitates said rotation.
19. An assembly according to claim 18 wherein said anchorage elements allow distraction of bone segments when inserted in bone.
20. An assembly according to claim 26 wherein the assembly is capable of simultaneous distraction of bone and retraction of soft tissue.
21. An assembly according to claim 20 wherein the retraction arms are incrementally rotationally adjustable to increase or decrease soft tissue retraction capacity.
22. An assembly according to claim 4 wherein each said retracting arm further comprises a distal end having a formation which engages said pin which engages said bone.
23. An assembly according to claim 22 wherein said distal end of each said retracting arms comprises an extension element which provides an axis of rotation for said retraction arms
24. An assembly according to claim 23 wherein said anchorage pins are each retained by a sleeve.
25. An assembly according to claim 24 wherein fixation of said allows said retractors to rotate about said distal ends
26. An assembly according to claim 25 wherein said means to facilitate rotation of each said retractor is a gripping handle.
27. An assembly according to claim 26 wherein each bone anchor pin includes a leading end point which engages said bone.
28. An assembly according to claim 27 wherein, there are two opposing pins located at a distal end of each retraction arm.
29. An assembly according to claim 28 wherein each bone anchor pin is detachably fitted to the retraction arms of said retraction assembly.
30. An assembly according to claim 29 wherein, the means to facilitate said rotation is a gripping handle.
31. An assembly according to claim 30 wherein a first retractor arm co operates with a second retractor arm in a scissor action.
32. An assembly according to claim 31 wherein the gripping handle has openings which receive a finger of a user.
33. An assembly according to claim 32 wherein the scissor action urges said opposing pins into engagement with bone.
34. An assembly according to claim 33 wherein when said pins are anchored in bone the retraction element rotates about an axis through said opposing pins.
35. A retraction arm for use in an assembly capable of retracting soft tissue during surgical procedures, the assembly comprising:
- an anchorage for engaging bone and which anchors the assembly to enable said tissue retraction by the retraction arm;
- the retracting arm having a first free end and a second end, the second end including a formation which allows the retraction arm to be detachably retained by said anchorage; said retention by the anchorage enabling the free end of the retraction arm to move through at least one degree of freedom relative to said anchorage.
36. A retraction arm according to claim 35 wherein the arm is capable of rotation about an axis through said second end.
37. A frame assembly for use in a soft tissue retraction and bone distraction assembly, the frame assembly comprising: two retention arms,
- a first bridge joining the retention arms, wherein each said retention arms have a first end attached to said bridge and a second free end;
- the retention arms each receiving and retaining thereon at least one retracting arm having a first free end and a second end, the second end including a formation which allows the retractor arm to be detachably retained by said retention arms enabling said retractor arms to rotate about said retention arms and slide therealong.
38. A frame assembly according to claim 37 further comprising first and secondary bridges each having an opening which receives an anchorage for engaging bone and which anchors the frame assembly.
39. A frame assembly according to claim 38 wherein, the frame assembly includes at least one opening enabling screw fixation of the assembly to bone.
40. A frame assembly according to claim 39 wherein the frame assembly includes two retention arms which receive respective opposing retraction arms.
41. A frame assembly according to claim 40 wherein, the frame assembly further comprises a bridge joining the retention arms.
42. A frame assembly according to claim 41 wherein each retractor arm engages a corresponding formation on the second end of the retractor arms, allowing the retractor arms to rotate about the retention arm and slide therealong.
43. A frame assembly according to claim 42 wherein each said retention arms have a first end attached to said bridge and a second free end.
44. A frame assembly according to claim 43 wherein the frame assembly is generally U shaped such that the first and second retention arms are parallel and disposed normally to the bridge member.
45. An assembly for combined retraction of wound margins of soft tissue and distraction of vertebrae during spinal surgery; the assembly including;
- a pair of pins anchored in said vertebrae;
- sleeves concentrically engaging said pins;
- means to apply a distraction force to said pins via said sleeves;
- a first retention arm having a first end including a recess capable of engaging one said pins and a second end including connection means which releasably receives a first retractor arm via a co operating mating profile;
- a second retention arm having a first end including a recess capable of engaging the other of said pins and a second end including connection means which releasably receives a second retractor arm via a mating profile; wherein said respective connection means each allow rotatable adjustment of each said retractor arms to retract said soft tissue margins during surgery.
46. An assembly according to claim 45 wherein sleeves concentrically engage said pins; the assembly further comprising means to apply a distraction force to said pins via said sleeves.
47. An assembly according to claim 46 wherein, the retention arms include spline formations providing a mating engagement which allows longitudinal and rotational adjustment of said retraction arms.
48. A retraction arm for use in a retraction assembly including an anchorage assembly and a pair of retraction arms, each said retraction arms comprising a first free end and a second end including a formation which engages said anchorage assembly; the anchorage assembly comprising;
- a frame assembly including a pair of retaining members which releasably receive respective said second ends of each said retracting arms; wherein the retaining members provide an axis of rotation for respective retracting arms; the frame assembly includes openings receiving fasteners enabling fixation of the frame assembly to bone; wherein the frame assembly is adjustable to accommodate bone location.
49. A retraction arm according to claim 88 wherein the retraction arms engage respective retention arms which provide an axis of rotation.
50. A retraction arm according to claim 49 wherein the retention arms include at least one spline which mates with a corresponding spline formation on the arms.
51. A retraction arm according to claim 50 wherein the at least one spline locks said retractor arms in a selected rotational orientation.
52. A retraction arm according to claim 51 wherein there is an array of spline formations on said retention arms engaging an array of corresponding formations on said blade.
Type: Application
Filed: Aug 13, 2005
Publication Date: Jul 23, 2009
Inventor: Kevin Seex (Kingswood)
Application Number: 11/660,466
International Classification: A61B 1/32 (20060101);