US20170143325A1

US20170143325A1 - Retractor devices for minimally invasive access to the spine

Info

Publication number: US20170143325A1
Application number: US15/198,349
Authority: US
Inventors: Jim R. Lynn; Russell W. Nelson
Original assignee: Pinnacle Spine Group LLC
Current assignee: Spine Holdings LLC
Priority date: 2011-11-02
Filing date: 2016-06-30
Publication date: 2017-05-25
Also published as: US9380932B1

Abstract

According to some embodiments, a retractor device for selectively moving (e.g., retracting) anatomical tissue of a subject during a minimally invasive procedure (e.g., accessing the lumbar or other portion of a spine during a spinal fusion procedure) comprises a main body comprising at least three sides (e.g., three, four, five sides, more than five sides, etc.). In some embodiments, the main body defines or otherwise forms a central opening, which comprises a center-point positioned along a centerline of the central opening. In some embodiments, the retractor device further comprises a plurality of movable members secured to the main body.

Description

PRIORITY DATA

This application is a continuation application of U.S. patent application Ser. No. 13/666,829, filed Nov. 1, 2012, which claims the priority benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/554,958, filed Nov. 2, 2011, the entireties of both of which are hereby incorporated by reference herein.

BACKGROUND

Field
This application generally relates to spinal treatment, and more specifically, to devices and instrumentation for accessing certain portions of the spine minimally invasively, and related systems and methods.
Description of the Related Art
Intervertebral discs can degenerate or otherwise become damaged over time. In some instances, an intervertebral implant can be positioned within a space previously occupied by a disc. Such implants can help maintain a desired spacing between adjacent vertebrae and/or promote fusion between adjacent vertebrae. In order to minimally invasively access a target portion of the spine, retractors and/or other access devices can be used. Accordingly, a need exists for improved retractor devices, as well as related instrumentation, tools, systems and methods.

SUMMARY

According to some embodiments, a retractor device for selectively moving (e.g., retracting) anatomical tissue of a subject during a minimally invasive procedure (e.g., accessing the lumbar or other portion of a spine during a spinal fusion procedure) comprises a main body comprising at least three sides (e.g., three, four, five sides, more than five sides, etc.). In some embodiments, the main body defines or otherwise forms a central opening, which comprises a center-point positioned along a centerline of the central opening. In some embodiments, the retractor device further comprises a plurality of movable members secured to the main body.
According to some embodiments, each side of the retractor device comprises a movable member. In other embodiments, the main body comprises a generally circular, oval or non-polygonal shape. In such embodiments, a plurality of movable members (e.g., two, three, four, more than four, etc.) is secured to the circular, oval or non-polygonal main body. According to some embodiments, a blade is secured to each movable member and configured to be moved together with a corresponding movable member to which the blade is secured. In some embodiments, each blade extends generally perpendicular to the main body.
In some embodiments, the blade comprises a distal end configured to extend into an anatomy of the subject. In some embodiments, each movable member is configured to move laterally relative to the main body, such that the blades secured to the movable members can be moved within the central opening defined by the main body. In some embodiments, each of the blades is configured to be selectively moved laterally past the center-point of the central opening. In one embodiment, each of the blades is configured to be selectively rotated (e.g., toe in or tow out) relative to an axis generally perpendicular to the main body. In some embodiments, the movable members are configured to be moved relative to one another so that the blades attached to said movable members generally form a cylindrical opening within the central opening defined by the main body.
According to some embodiments, the main body comprises four or more sides. In some embodiments, the main body comprises one or more of the following shapes: square, other rectangular, pentagonal, triangular, hexagonal, other polygonal, circular, oval, irregular and the like. In some embodiments, each of the blades is removably secured to a corresponding movable member. In some embodiments, at least of the blades is irremovably secured to a corresponding movable member. In some embodiments, each movable member is operatively coupled to a first controller and a second controller, wherein the first controller is configured to selectively adjust a lateral position of the movable member (e.g., to move the movable member and a blade secured thereto closer or further away from an adjacent movable member and blade). In some embodiments, the second controller is configured to selectively rotate the blade attached to the movable member (e.g., toe-in or toe-out). In some embodiments, each of the movable members and the corresponding blade secured thereto can be moved independently of one or more of the other movable members and corresponding blades.
According to some embodiments, the first controller and/or the second controller comprises a rotatable knob, a button, a lever, a release mechanism and/or the like. In one embodiment, the movable members are moved using a rack and pinion mechanism, another gear and/or mechanical system. In some embodiments, the blade comprises at least one slot, channel, recess or other receiving portion. In some embodiments, such a slot extends along at least a portion of the length of the blade (e.g., only along a portion of the blade length, along the entire or substantially along the entire blade length, etc.). In some embodiments, at least one slot of the blade is configured to slidably receive a shim, said shim being configured to generally extend a distal end of said blade (e.g., to extend the length of the blade so as to reach a nerve or other sensitive anatomical area that can be selectively moved by the shim and blade). In some embodiments, the blade is configured to slidably receive an illumination device configured to provide light to a portion of the subject's anatomy being accessed. In some embodiments, the illumination device comprises a fiber-optic, LED and/or other light source.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the present application are described with reference to drawings of certain embodiments, which are intended to illustrate, but not to limit, the present disclosure. It is to be understood that these drawings are for the purpose of illustrating concepts of the present disclosure and may not be to scale.

FIGS. 1-13 illustrate various perspective views of one embodiment of a retractor used to access a targeted portion of a patient's spine;

FIG. 14 illustrates a top view of the retractor of FIGS. 1-13;

FIG. 15A illustrates a perspective view of a blade configured to secure to a retractor according to one embodiment;

FIG. 15B illustrates a perspective view of a shim configured to be received within a channel or other portion of a blade according to one embodiment;

FIG. 16 illustrates the shim of FIG. 15B cooperatively secured to the blade of FIG. 15A;

FIG. 17 illustrates a perspective view of an alignment device configured to be used with the retractor;

FIG. 18 illustrates a perspective view of the retractor device of FIG. 17 being used together with one embodiment of a retractor in order to generally align the blades secured to said retractor; and

FIG. 19 illustrates one embodiment of the illumination device or component secured to the retractor of FIG. 18.

DETAILED DESCRIPTION

A variety of embodiments and examples described herein illustrate various configurations that may be employed to achieve desired improvements. The particular embodiments and examples are only illustrative and not intended in any way to restrict the general nature of the inventions presented and the various aspects and features of and relating to these inventions.
FIGS. 1 through 13 illustrate various perspective views of one embodiment of a retractor 2000 that is particularly useful in procedures using a lateral access approach to a targeted portion of the spine. As shown, the overall shape of the retractor 2000 can be generally rectangular (e.g., square) or diamond. However, in other embodiments, the shape of the retractor can vary, as desired or required. For instance, in some embodiments, the retractor comprises a generally circular, oval, other polygonal (e.g., triangular, pentagonal, hexagonal, octagonal, etc.), irregular and/or any other shape. The retractor can be used in a variety of minimally invasive approaches to a subject's spine, including without limitation, lateral, posterior, transforaminal and/or any other approach, as desired or required. In addition, the retractor can be used to access any portion of a subject's spine, including the lumbar portion, thoracic portion, cervical portion and/or the like.
With continued reference to FIG. 1, the retractor 2000 can include one or more sites 2014, 2016 to which a rigid arm 2100 may attach. In some embodiments, the arm 2100 is coupled to a surgery table and/or other fixed or immovable object in order to properly secure the retractor during a particular procedure. In the illustrated embodiment, the retractor comprises a total of four movable members 2020A-2020D that are generally offset by about 90 degrees relative to each other. As is discussed in greater detail herein, the movable members 2020A-2020D can be configured to be selectively moved either toward or away from one another during the course of a particular surgery, as desired or required. In some embodiments, the movable members 2020A-2020D can be moved independently of one another. This can help improve the retractor's flexibility and can facilitate the manner in which tissue is retracted by the surgeon. In one embodiment, each movable member 2020A-2020D is adapted to securely receive a blade 2040.
In some embodiments, the retractor comprises more or fewer than four movable members 2020A-2020D (e.g., two, three, five, six, more than six, etc.), as desired or required for a particular application or procedure. Accordingly, a retractor can include more or fewer than four blades 2040. In some embodiments, the blades are configured to generally form a cylinder when moved adjacent to one another. As discussed in greater detail herein (e.g., with reference to FIGS. 17 and 18), an alignment device can be used to ensure than the blades are properly aligned relative to one another and/or with one or more tissue dilators used in a procedure.
With continued reference to the embodiment illustrated in FIGS. 1-14, each of the blades 2040 generally extends about a quarter of a circle (e.g., approximately 90 degrees). Therefore, when the blades 2040 are moved toward the center-point CP (FIG. 14) of the retractor 2000, the blades cooperate to form a generally full cylindrical shape. Thus, the blades can be generally identical to one another. However, in other arrangements, one or more of the blades can be disproportionally larger than one or more of the other blades. Further, in retractor comprising more or fewer than four blades 2040, the circumferential or radial extent of each blade can be less or more than about 90 degrees. For example, in embodiments comprising three blades and five blades, each blade can extend approximately 120 degrees and 72 degrees, respectively.
As best illustrated in FIG. 1, the blades 2040 can be configured to converge or otherwise come in proximity with one another (e.g., toward the center-point CP of the retractor 2000) so as to snugly surround a dilator D (e.g., a dilator with a diameter of about 18 mm). For example, the retractor can be inserted within a patient's anatomy when the blades are in the orientation depicted in FIG. 1 by sliding the blades 2040 along the outer surface of a dilator. In some embodiments, once the blades have been advanced into the patient's anatomy, the dilator D can be removed. In one embodiment, in addition to having a desired lateral orientation relative to one another so as to help form a generally cylindrical shape, the blades 2040 can be tilted, angled or otherwise skewed (e.g., toe-in, toe-out, etc.) relative to the outer surface of a dilator D. For example, the blades can be oriented so that their distal ends are tilted slightly (e.g., between about 0 and 10 degrees) toward the center-point CP of the retractor 2000. This can help ensure that the blades remain against or along the outer surface of a dilator D as the retractor is advanced into a patient's anatomy. In some embodiments, such a “hugging” feature can help prevent or reduce the likelihood of blade splaying.
With continued reference to FIGS. 1-14, each movable member 2020A-2020D of the retractor 2000 can comprise one or more dials or other controllers. For example, in the illustrated arrangement, each movable member 2020A-2020D comprises an inner dial 2024A-2024D and an outer dial 2028A-2028D. Each dial or other controller or feature can be advantageously used to change the position, orientation and/or other positional aspect of the corresponding blade 2040. In some embodiments, for example, the outer dials 2028A-2028D change the lateral position of the movable members. Thus, the outer dials 2028A-2028D permit a surgeon or other practitioner to adjust the position of the movable members (and thus the blades 2040 connected thereto) relative to one another (e.g., generally along the plane in which the movable members 2020A-2020D are located). By way of example, rotating the outer dial or knob 2024 (e.g., in a clockwise direction) causes the corresponding movable member 2020A-2020D (and thus, the blade attached thereto) to retract or move away from the center-point CP of the retractor. In other embodiments, however, controllers can be of a different type (e.g., other types of knobs, dials, levers, buttons, etc.) and/or controller can operate differently, as desired or required by a particular application or use.
According to some embodiments, the movable members 2020A-2020D comprise rack and pinion systems. Thus, each outer dial or knob 2028A-2028D can be mechanically coupled to a corresponding rack and pinion in order to retract the blade 2040. Further, each movable member 2020A-2020D can comprise a release 2032A-2032D, which causes the rack and pinion to temporarily disengage. Such a release allows one or more of the blades to be quickly moved to a desired lateral position. Thus, the movable members 2020A-2020D (together with the corresponding blades 2040A-2040D) can be moved toward their original position (e.g., to or near the center-point CP of the retractor 2000).
In some embodiments, the inner dials or knobs 2024A-2024D are configured to modify the pitch or angle of the corresponding blades 2040A-2040D. Thus, by rotating such a dial 2024A-2024D (e.g., in a clockwise direction), the distal free end of the corresponding blade 2040A-2040D can tilt or otherwise move relative to the proximal end (e.g., the end that is coupled to the movable member). In some embodiments, the inner dial or knob can be rotated in both directions in order to permit the distal end of the blade to be moved either away or toward the center-point CP of the retractor. In some embodiments, each blade, due in part to the ability to adjust in toe-in or toe-out orientation (e.g., using the inner dials), can be independently moved past the center-point CP (e.g., or a longitudinal axis extending through the center-point CP) of the retractor. Such a configuration can advantageously enhance the surgeon's ability to easily and robustly customize the position of the blades within a patient's anatomy. For example, one or more of the blades can include a toe-out orientation (e.g., tilted toward the center-point CP), while other blades can include a toe-in orientation (e.g., tilted away from the center-point CP). In addition, the distal end of one or more of the blades 2040 can be moved past the center-point CP, as desired or required. The ability of the blades to move past the CP of the retractor can advantageously eliminate the needs for extra instrumentation (e.g., a separate device that would otherwise be inserted within the central opening of the retractor to selectively move tissue) and/or eliminate the need for additional personnel required to perform a particular procedure.
In some embodiments, moving a movable member using the inner dial (e.g., generally along the same plane of the movable members) is referred to dragging the blade. Further, moving the distal or free end of the blade using the outer dial can be referred to as sweeping the blade. Thus, in some embodiments, the retractors disclosed herein, or equivalents thereof, are capable of dragging and/or sweeping each blade independently of one another. In addition, the retractor can be advantageously configured so that each blade can be independently swept past the center-point CP of the retractor (e.g., or the longitudinal axis positioned along the center-point CP). According to some embodiments, the blades maintain a particular tilt or angle once the inner dials have been adjusted, without the need to maintain resistance or other opposing force.
In FIG. 3, the retractor 2000 comprises light shims or coupling members 2060 that are secured along the top portions of two of the blades 2040. Such light shims or coupling members 2060 can be sized, shaped and otherwise configured to releasably or permanently couple to a corresponding portion of the movable member and/or blade. In some embodiments, a light shim 2060 comprises one or more openings 2062 through which a wire W (e.g., a Kirschner Wire or K Wire) can pass.
However, in other embodiments, a light source or illumination device can be configured to releasably secure to one or more blades or other portions of the retractor. For example, as illustrated in FIGS. 18 and 19 and discussed in greater detail below, a fiber-optic light device can be sized and shaped to slide at least partially within a slot or other opening of a blade.
As discussed above and illustrated in FIG. 7, the distal end of the blade 2040 can be configured to be selectively tilted (e.g. either in a toe-in or toe-out orientation) along a particular angle range 2042. For example, the blade 2040 can be tilted or angled using one or more dials or knobs. Such a feature can facilitate moving one or more of the blades 2040 of the retractor 2000 around and past a nerve bundle N or other portion of the anatomy.
In certain instances, it is desirable or necessary to effectively extend the length of one or more blades 2040 of the retractor. For example, as illustrated in FIG. 8, the distal end of a blade 2040 may not be long enough to reach the depth of a nerve bundle N or other portion of the anatomy that must be carefully retracted or moved by the blade 2040. Thus, in some embodiments, as illustrated in FIGS. 8-13, one or more of the blades 2040 can be configured to receive a shim or other extension portion 2070.
With reference to FIGS. 15A, 15B and 16, the lengthening shim or extender portion 2070 can be configured to slide within a corresponding channel, slot or other opening 2044 of the blade 2040. For instance, in one embodiment, the lengthening shim 2070 comprises a flange or other protruding portion or feature 2072 that is sized, shaped and otherwise configured to be received by the slot or channel 2044 of the blade 2040. In some embodiments, therefore, such a shim 2070 can be coupled to a blade 2040 and be advanced along the distal end of the blade 2040. In some embodiments, if the shim 2070 is moved far enough into the blade's channel 2044, the shim will engage the blade 2040 in such a manner so that it cannot be easily withdrawn (e.g., proximally relative to the blade). For example, the shim and the corresponding distal portion of the blade can comprise a ratchet and/or other positive engagement feature or mechanism. This can help ensure that the shim 2070 will perform as needed (e.g., to act as an extension along the distal end of blade 2040). In some embodiments, a special release or other feature can be included to permit the user to retract the shim or other extender against a ratchet or other positive engagement feature or mechanism. As mentioned above and discussed in greater detail below with reference to FIGS. 18 and 19, one or more light or other illumination devices or components (e.g., a removable fiber optic light attachment) can be sized, shaped and/or otherwise configured to be positioned into and moved within a slot, channel or other opening of a blade. Thus, the targeted area of the patient or other subject can be advantageously illuminated to assist the surgeon or other practitioner to execute a particular procedure.
One embodiment of how the shim or other extending portion 2070 can be used to enhance the tissue retraction capabilities of the retractor is illustrated in the time-sequential images of FIGS. 8-13. As shown, once a surgeon or other practitioner appreciates that the length of one or more blades needs to be extended, he or she can connect a shim or other extension device or component to the corresponding blade members. In some embodiments, as illustrated and discussed herein, such shims or extenders are sized, shaped and/or otherwise configured to fit within and be moved relative to a slot, channel or other feature of the blade. However, in other embodiments, such extenders can attach to the blades using one or more other devices or methods, as desired or required.
According to some embodiments, for example, the shims or other extender portions can be pushed, urged or other moved toward the distal ends of the corresponding blades 2040 (e.g., until there is a positive engagement with a ratchet mechanism) using any elongated tool or member.
With continued reference to FIGS. 9 and 10, the angle and/or lateral position of the corresponding blade 2040 may need to be adjusted in order to get around a particular portion of the anatomy (e.g., a nerve or nerve bundle, organ, muscle tissue and/or other sensitive area of the anatomy that needs to be moved by the blade). Thus, as noted above, one or more blades can be dragged and/or swept as needed. In some embodiments, the retractor disclosed herein is configured so that one or more of the blades 2040 can be selectively swept (e.g., in a direction generally represented by arrow 2043 in FIG. 10) past the center-point CP of the retractor. This helps increase the flexibility of the retractor and allows the surgeon to carefully retract or move tissue to levels that otherwise may not have been possible.
Thus, a surgeon can selectively manipulate one more dials to precisely and easily move one or more of the blades into any one of a number of positions during a retraction procedure. For example, with the assistance of a lengthening shim or extender portion 2070 secured to one of the blades 2040, the practitioner can carefully move a nerve bundle N, muscle tissue and/or other desired anatomical area along the outside of the blade 2040 (see, e.g., FIGS. 8-13). In some embodiments, the length of the lengthening shim 2070 is approximately one inch. However, the length of the shim 2070 can be greater than 1 inch (e.g., 1.5, 2 inches, more than 2 inches, values between the foregoing lengths, etc.) or shorter than 1 inch (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95 inches, less than about 0.1 inches, values between the foregoing lengths, etc.), as desired or required.
To assist in the description of the disclosed embodiments, words such as upward, upper, bottom, downward, lower, rear, front, vertical, horizontal, upstream, downstream have been used above to describe different embodiments and/or the accompanying figures. It will be appreciated, however, that the different embodiments, whether illustrated or not, can be located and oriented in a variety of desired positions.
As discussed herein, one or more of the blades can be configured to advantageously move past the center-point CP of the retractor device (e.g., the center-point of the retractor's main opening if all blades have the same or similar lateral orientation). Thus, the blades can be used to easily and quickly access a particular portion of the spine (or other portion of the subject's anatomy) while selectively and safely moving sensitive tissues (e.g., nerves, organs, etc.) around the opening (e.g., to create a desired clearance or accessway).
With continued reference to FIGS. 14, 15A and 15B, the blades 2040 can be removably secured within corresponding recesses 2022A-D of the movable members of the retractor. Accordingly, the blades can be easily removed and/or replaced, as desired or required (e.g., for maintenance, sterilization, etc.).
According to some embodiments, a generally solid alignment device can be used to generally align and orient the different blades of a retractor relative to one another. FIG. 17, for example, illustrates one embodiment of such an alignment device 3000. In some arrangements, the alignment device 3000 comprises a generally closed outer surface. In some embodiments, the outer diameter of the alignment device 3000 (which can be referred to as a drone dilator or dilator guide) matches or substantially matches the outer diameter of a dilator or similar device that has been inserted into the subject prior to using the retractor. For example, in some embodiments, the outer diameter of the alignment device 3000 is approximately 18 mm. However, in other embodiments, the outer diameter of the device 3000 can be smaller than 18 mm (e.g., about 16 mm, 14 mm, 12 mm, 10 mm, less than about 10 mm) or greater than 18 mm (e.g., about 20 mm, 22 mm, greater than about 22 mm), as desired or required.
In some embodiments, once the largest dilator has been inserted into the patient or other subject, the surgeon or other clinician can use a retractor 2000 similar to any of the embodiments disclosed herein. The blades of the retractor can be moved (e.g., using knobs, release levers and/or other controllers) so as to snugly or substantially snugly surround the exterior of the alignment device 3000, as illustrated in FIG. 18. In some embodiments, the blades can be adjusted so their interior surfaces substantially contact the exterior surface of the alignment device 3000. As shown, the surgeon can hold the blades of the retractor 2000 in place around the alignment device 3000 and align the alignment device over the largest dilator positioned within the subject. With the device 3000 aligned with the dilator, the surgeon can advance the retractor 2000 into the patient, such that the blades move along the outside surface of the largest dilator. This provides a convenient, consistent and reliable method of inserting the retractor blades into the subject. As the blades move downwardly into the subject's anatomy, the alignment device 3000 will stay in place, effectively allowing the device 3000 to be moved relative to the blades and the rest of the retractor. As discussed herein, once the retractor blades have been properly advanced into the subject, the alignment device 3000 and/or any dilators can be removed from the subject.
According to some embodiments, the alignment device 3000 comprises one or more plastic and/or other materials. For example, the device 3000 can comprise polyoxymethylene (POM), also known as acetal, polyacetal or polyformaldehyde. However, any other plastic, composite, metal, alloy and/or other material can be included in the device 3000, as desired or required. The device 3000 is advantageously configured to withstand the forces, moments and/or other elements to which it may be exposed, both during a procedure and during related tasks (e.g., cleaning or sterilization, transport, etc.).
With further reference to FIG. 18, a light or illumination device or component 4000 can be sized, shaped and/or otherwise configured to secure to one or more blades and/or another portion of the retractor 2000. A detailed view of the embodiment of the illumination device 4000 of FIG. 18 is illustrated in FIG. 19. As shown, the illumination device 4000 can comprise a hub or other coupling 4040 (e.g., for attachment to a light source), a flexible cable 4020 and the illumination output portion 4010. In some embodiments, the illumination output portion 4010 is sized, shaped and/or otherwise configured to be releasably inserted (e.g., at least partially) within a slot, channel or other receiving feature or portion of a blade, as illustrated in FIG. 18. Thus, one or more illumination devices 4000 can be secured to a retractor device 2000 to provide light to the anatomical area of the subject being accessed. According to some embodiments, the light device 4000 comprises fiber optic technology, LED and/or any other source to generate light.
Although the subject matter provided in this application has been disclosed in the context of certain specific embodiments and examples, it will be understood by those skilled in the art that the inventions disclosed in this application extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the subject matter disclosed herein and obvious modifications and equivalents thereof. In addition, while a number of variations of the inventions have been shown and described in detail, other modifications, which are within the scope of these inventions, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the inventions disclosed herein. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combine with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of the subject matter provided in the present application should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.

Claims

1-20. (canceled)

21. A retractor device for selectively moving anatomical tissue of a subject during a minimally invasive procedure, comprising:

a main body comprising a generally rectangular shape, said main body defining a central opening, said central opening comprising a center-point positioned along a centerline of said central opening;

a plurality of movable members secured to the main body;

a blade secured to each movable member and configured to be moved together with a corresponding movable member to which said blade is secured;

wherein each blade extends generally perpendicular to the main body, said blade comprising a distal end configured to extend into an anatomy of the subject;

wherein each movable member is configured to move laterally relative to the main body, such that the blades secured to the movable members can be moved within the central opening defined by the main body;

wherein each of the blades is configured to be selectively moved laterally past the center-point of the central opening;

wherein each of the blades is configured to be selectively independently rotated relative to: (i) an axis generally perpendicular to the main body, and (ii) each of the other blades; and

wherein the movable members are configured to be moved relative to one another so that the blades attached to said movable members generally form a cylindrical opening within the central opening defined by the main body.

22. The retractor device of claim 21, wherein each of the blades is removably secured to a corresponding movable member.

23. The retractor device of claim 21, wherein each movable member is operatively coupled to a first controller and a second controller, said first controller being configured to selectively adjust a lateral position of the movable member, and said second controller being configured to selectively rotate the blade attached to said movable member.

24. The retractor device of claim 23, wherein at least one of the first controller and the second controller comprises a rotatable knob.

25. The retractor device of claim 21, wherein the movable members are moved using a rack and pinion mechanism.

26. The retractor device of claim 21, wherein the blade comprises at least one slot.

27. The retractor device of claim 26, wherein the at least one slot of the blade is configured to slidably receive a shim, said shim being configured to generally extend a distal end of said blade.

28. The retractor device of claim 26, wherein the at least one slot of the blade is configured to slidably receive an illumination device, said illumination device being configured to provide light to a portion of the subject's anatomy being accessed.

29. The retractor device of claim 28, wherein the illumination device comprises a fiber-optic or LED light source.

30. The retractor device of claim 21, wherein the main body forms a diamond or square shape.

31. A retractor device for selectively moving anatomical tissue of a subject during a minimally invasive procedure, comprising:

a main body comprising at least three sides, said main body defining a central opening, said central opening comprising a center-point positioned along a centerline of said central opening;

a plurality of movable members secured to the main body;

32. The retractor device of claim 31, wherein the main body comprises four or more sides.

33. The retractor device of claim 31, wherein each of the blades is removably secured to a corresponding movable member.

34. The retractor device of claim 31, wherein each movable member is operatively coupled to a first controller and a second controller, said first controller being configured to selectively adjust a lateral position of the movable member, and said second controller being configured to selectively rotate the blade attached to said movable member.

35. The retractor device of claim 34, wherein at least one of the first controller and the second controller comprises a rotatable knob.

36. The retractor device of claim 31, wherein the movable members are moved using a rack and pinion mechanism.

37. The retractor device of claim 31, wherein the blade comprises at least one slot.

38. The retractor device of claim 37, wherein the at least one slot of the blade is configured to slidably receive a shim, said shim being configured to generally extend a distal end of said blade.

39. The retractor device of claim 37, wherein the at least one slot of the blade is configured to slidably receive an illumination device, said illumination device being configured to provide light to a portion of the subject's anatomy being accessed.

40. A method for selectively moving anatomical tissue of a subject during a minimally invasive procedure, comprising:

positioning a retractor device adjacent a subject, the retractor device comprising a main body comprising a generally rectangular shape, said main body defining a central opening, the central opening comprising a center-point positioned along a centerline of said central opening;

wherein the retractor device further comprises:

a plurality of movable members secured to the main body;

wherein each of the blades is configured to be selectively moved laterally past the center-point of the central opening; and

moving the movable member relative to one another so that the blades attached to said movable members generally form a cylindrical opening within the central opening defined by the main body.