WO2003043505A1

WO2003043505A1 - Methods and instrumentation for disc space distraction

Info

Publication number: WO2003043505A1
Application number: PCT/US2002/037151
Authority: WO
Inventors: Eric Martz; Brian Ruffner
Original assignee: Osteotech, Inc.
Priority date: 2001-11-19
Filing date: 2002-11-19
Publication date: 2003-05-30
Also published as: AU2002346448A1

Abstract

An instrumentation system for use in spine surgery includes a distractor configured to be inserted in a disc space and to rotate therein to gradually distract the disc space, and a retractor detachably coupled to distractor to provide a support surface for a retracted blood vessel, or other such internal structure, and formed with a guide channel for directing surgical instruments and an implant into the distracted and prepared disc space.

Description

METHODS AND INSTRUMENTATION FOR DISC SPACE DISTRACTION

CROSS REFERENCE TO RELATED APPLICATION

The application is based on and claims priority to U.S. Provisional Application No. 60/334,279 filed on November 19, 2001.

BACKGROUND

1. Technical Field

[0001] The present invention relates to an instrumentation system for performing spine surgery through an anterior, lateral, and/or anterolateral approach. In addition, the present invention relates to a method for spinal distraction and, more particularly to a method of using an instrumentation system, configured in accordance with the present disclosure, for performing retraction and accessing of the disc space, distraction of the vertebral bodies, and preparation of the vertebral endplates for spine surgery.

2. Background of Related Art

[0002] Currently during spinal surgery and in particular during the performance of an interbody fusion procedure, an orthopedic surgeon will require the assistance of a vascular surgeon when approaching the spine from the anterior direction. In general, an orthopedic surgeon specializes in the medical and surgical treatment of disorders and injuries to bones (i.e., the spine), muscles and joints, while a vascular surgeon deals with diseases of all the blood vessels of the body (i.e., arteries and veins).

[0003] The technique of spinal surgery associated with an anterior surgical approach has not substantially changed since its original performance but the instruments designed for this procedure have been modified and improved upon to make the operation easier and safer. While these instruments are effective for their respective use, none of them is configured to conveniently support an internal structure including, but not limited, to a blood vessel during an interbody fusion procedure.

[0004] During an anterior interbody fusion, once a vertebral disc space is accessed by the orthopedic surgeon, blood vessels are kept out of the surgical field in order for the orthopedic surgeon to be able to operate. Most typically, these blood vessels must be kept away during a distraction done in the lumbar region of the spine._The presence of the vascular surgeon within a confined surgical space as well as the fatigue and other human factors associated with manually holding the retracted blood vessel may cause substantial inconvenience for the orthopedic surgeon.

[0005] Therefore, the need exists for an instrumentation system which eliminates the need for the vascular surgeon to manually maintain the retraction of the blood vessels out of the surgical field during a spinal distraction. In addition, the need exists for a method of performing anterior spinal fusion without the need of a vascular surgeon holding the blood vessels out of the surgical field.

SUMMARY OF THE INVENTION

[0006] An instrumentation system configured in accordance with the invention maintains blood vessels, initially retracted by a vascular specialist, out of a surgical site during the entire spinal surgery without the use of an external aid rendered by the vascular specialist.

[0007] In accordance with one aspect of the invention, the instrumentation system includes a distractor shaped and dimensioned to penetrate into the disc space and to rotate within it to displace adjacent vertebra away from one anther. Furthermore, upon distracting the disc space, the distractor provides a support for a retractor removably mounted on the distractor and configured to maintain the blood vessel out of an operational site or surgical field.

[0008] The retractor is shaped to prevent excessive compression of the blood vessel and its damage during the spinal surgery while maintaining the retracted blood vessel of the incision from interfering with the surgeon's view and instruments.

[0009] In accordance with yet another aspect of the invention, the retractor is configured with an inner surface allowing multiple endplate preparatory instruments and an interbody fusion spinal implant to be guided into the disc space. Multiple implementations of the retractor allowing guidance of the instrument into the disc space are envisioned within the scope of the invention.

[0010] One of the inventive embodiments of the retractor includes a monolithic body having the inner surface dimensioned to closely approximate a width of the various disc preparation instruments. Alternatively, the retractor may be formed with a single half or a pair of halves, which are used together as a combination or individually. Each of the halves has the inner surface configured to minimally obstruct the view of the surgical field during the spinal surgery and to guide the instruments into the disc space.

[0011] Accordingly, the retractor vessel attached to the distractor already in place within the disc space will allow the surgeon to not only implant the interbody fusion implant, but will also allow the surgeon open access to the vertebral bodies to implant a fixation plate. Such a fixation plate could enhance the stability of the operated motion segment, and its implantation would be greatly facilitated by a retractor / distractor spinal instrument system described.

[0012] Yet a further aspect of the invention relates to a guide assembly configured to stabilize the retractor in a desired position in which the latter can be used both as the blood vessel supporter and as a guide for the endplate preparatory instruments and the spinal implant. The guide assembly allows the retractor to linearly move along the distractor. In accordance with different embodiments implementing this inventive aspect, the guide assembly includes a slot, which is formed on one of the opposing surfaces of the retractor and distractor, and a keyed formation, which is provided on the other opposing surface and is shaped complementary to the inner surface of the slot to allow the retractor to slide, but not to rotate.

[0013] According to another aspect of the invention, the guide assembly is so dimensioned that when the retractor is mounted on the distractor and moves therealong, the cooperating opposing surfaces lie flush with one another. The advantage of such a structure is that the entire inner surface of the sidewall of the retractor can be provided with various guide surfaces and guides tracks directing a variety of endplate preparatory instruments into the disc space.

[0014] Still a further aspect of the invention relates to an anchoring structure formed on the distal surface of the retractor, which opposes the anterior faces of the vertebra, and the outer surface of the distractor, which faces one of the opposite end plates. The anchoring structure is configured to facilitate engagement between the vertebra and the components of the inventive instrumentation system and to prevent rotational motion between the adjacent vertebra and each of the distractor and the retractor, as well as between the retractor and distractor. As a result of such a stabilized structure, the disc space is properly prepared, and the spinal implant is correctly inserted into the prepared disc space.

[0015] It is, therefore, a principle object of the invention to provide an instrumentation system including a retractor configured to maintain a blood vessel out of the surgical field during a spinal surgery without the use of an external aid, while simultaneously allowing open access to the intervertebral disc space. [0016] Still another object of the invention is to provide the instrumentation system with a distractor configured to rotate within and distract a disc space and to support the retractor so as to facilitate insertion of various end plate preparatory instruments and a spinal implant into a distracted disc space.

[0017] Yet a further object of the invention is to provide the instrumentation system configured to reliably engage surrounding and opposing surfaces of the disc space and, as a consequence, to enhance preparation of the disc space leading to the correct placement of the spinal implant in the prepared spinal space.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages will become more readily apparent from the following specific description of the inventive anterior instrumentation system described below with reference to the drawings, wherein:

[0019] FIG. 1 is a perspective view of a spinal instrumentation system in accordance with the present disclosure;

[0020] FIG. 2 is a perspective view of a pair of paddle distractors in accordance with the present disclosure;

[0021 ] FIG. 3 is a perspective view of a vessel retractor in accordance with the present disclosure;

[0022] FIG. 4 is an anterior view of a disc between a pair of adjacent vertebral bodies;

[0023] FIG. 5 is an anterior view of the disc space of FIG. 4 with a first paddle distractor, according to the present disclosure, positioned into the disc space prior to rotating the first paddle distractor 90° in the disc space; [0024] FIG. 6 is a partial anterior view of the disc space of FIG. 4 with the first paddle distractor rotated 90° into position;

[0025] FIG. 7 is a partial anterior view of the disc space of FIG. 6 with a second paddle distractor, according to the present disclosure, positioned into the disc space on a side opposite the first paddle distractor;

[0026] FIG. 8 is a partial anterior view of a spinal column with a vessel retractor, according to the present disclosure, in position over the paddle distractors;

[0027] FIG. 9 is an anterior view of the spinal column, with the vessel retractor in position and depicting the placement of the blood vessels;

[0028] FIG. 10 is a perspective view of the spinal column with the vessel retractor in place and in combination with a surgical instrument;

[0029] FIG. 11 is a front perspective view of a vessel retractor according to an alternative embodiment of the present disclosure;

[0030] FIG. 12 is perspective view of the vessel retractor of FIG. 11 in combination with a paddle distractor shown in place;

[0031 ] FIG. 13 is a front perspective view of a pair of vessel retractors as shown in FIG. 11 in combination with a pair of paddle distractors; arid

[0032] FIG. 14 is a rear perspective view of the pair of vessel retractors as retractors as shown in FIG. 13.

[0032'] FIG. 15 is a front elevational view of a fixation plate. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0033] With reference now to the drawings, wherein like reference numerals represent like elements throughout the several views, and initially to FIGS. 1-3, there is disclosed a preferred embodiment of an anterior ramp instrument system 100. The anterior ramp instrument 100 includes a left and a right paddle distractor 102 and 104 respectively and a vessel retractor 200.

[0034] In particular, with reference to FIG. 2, each paddle distractor 102 and 104 is provided to distract a disc space. Each paddle distractor 102 and 104 generally includes a distal portion formed with a body 106 having a rounded upper surface 108 and a planar lower surface 110. The rounded upper surface 108 extends from an outer surface 112 to an inner surface 114 of each paddle distractor 102 and 104 such that the outer surface 112 has a height which is less than a height of the inner surface 114. The rounded upper surface 108 has its radius of curvature located within the body portion 106 such that the arcuate portion of the rounded upper surface 108 extends outwardly from the body portion 106. The rounded surface 108 allows more gradual and easier distraction of the vertebral endplates and, structurally, can be formed as a continuous surface extending between the outer 112 and inner 114 surfaces. Alternatively, the surface 108 may have a flat region 103 interrupting the continuity of the rounded region and extending parallel to lower planar surface 110.

[0035] The planar lower surface 110 is provided with a pointed ridge 116 extending therefrom and running along at least part of the length of the body portion 106. While a pointed ridge 116 has been disclosed, it is envisioned that any pointed or keyed projection can extend from the lower surface 110 of the body portion 106, e.g., spikes, cones, etc. Rotation of the paddle distractor causes the projection 116 to engage one of the end plates of a respective vertebrae and, thus, anchor the paddle distractor therein in a manner preventing relative rotation motion between the vertebrae and the distractor.

[0036] The geometry of the paddle distractor can vary. For example, instead of the upper surface 108, the lower surface 110 of the paddle distractor can be rounded. To prevent relative rotational motion between the vertebrae and the paddle distractor, the keyed projection can be formed on the surface 108. Alternatively, both the upper 108 and lower 110 portions each can have the keyed projection engaging a respective end plate to ensure the position of the paddle distractor within the disc space.

[0037] The body portion 106 is configured and adapted such that the dimension between the rounded upper surface 108 and the planar lower surface 110 is greater than the dimension between the outer surface 112 and the inner surface 114.

[0038] Each paddle distractor 102 and 104 includes an arm 118 extending from a rear surface thereof. Arm 118 includes a ridge 120 formed on one of the opposite sides of the arm and projecting upwardly, downwardly or in opposite directions along at least a portion of the entire length thereof. Arm 118 has a thickness substantially equal to the dimension between the outer surface 112 and the inner surface 114 of the body portion 106. A height of the arm 118 is less than the dimension between the rounded upper surface 108 and the planar lower surface 110 of the body portion 106.

[0039] Each paddle distractor 102, 104 may be formed as an assembly typically including a body portion, an arm, a shaft dimensioned to advance the body portion and the arm from an entry point to a vertebral structure, and a T-shaped handle attached to the shaft. Advantageously, the distractor is formed as a modular unit including a first modification wherein the shaft and the handle form one sub-unit and the arm and the distal body constitute another unit detachably attached to the one unit. These units are detached after the disc space is decompressed so that only a structure, as shown in FIG. 2 and including the distal body portion 106 and the arm 118, remains available during the rest of the surgery.

[0040] Still another modification of the modular distractor may include the distal body 106 formed as a separate unit detachably engaged with the arm 118, which is in turn, is an integral part with the shaft and the handle. Similarly to the previously discussed structural modification, upon the distraction of the disc space by the distal body 106, the rest of the distractor including the arm 118 is detached and removed from the surgical site. Attachment between the units of the distractor may include, for example, variously shaped and dimensioned mating protrusions and detents formed on engaging surfaces of the distractor's units.

[0041] To control penetration of the body 106 into the disc space, an outer surface 105 of the arm 118, whether the latter is or is not detachable from the body, has a protrusion or protrusions 107 configured to engage outer surfaces of the adjacent vertebra and to prevent further displacement. The protrusion(s) 107 is placed on the outer surfaces 105 so that when it comes into contact with the outer surfaces of the vertebra, the body portion 106 would be advanced into the disc space at a desired depth.

[0042] Turning now in particular to FIG.3, vessel retractor 200 includes a base wall 202 and a pair of integrally formed upstanding parallel vertical side walls 204. Each side wall includes an elongated slot 206 formed therein and including a channel 208 formed along the upper surface thereof. In practice, the cross section of the slot 206 is configured and adapted to correspond to the cross section of the arm 118 of each paddle distractor 102 and 104, if the body 106 and the arm 118 are configured as an one-piece body. Although not shown, the retractor may have a surface extending complementary to the protrusion 107 (FIG. 2) configured to stop uncontrollable penetration of the distractor 102, 104 into the disc space. In this manner, each arm 118 is configured and adapted to be slidingly received into each slot 206 and is prevented from twisting, once inserted into a respective slot 206 upon the engagement between the ridge 120 and the channel 208.

[0043] Numerous modifications of the above-disclosed structure are envisioned within the scope of the invention. For instance, the channel 208 can be formed along the lower portion of the slot 206. The criticality of the slot 206 and the channel 208 lies in their respective shapes. The slot 206 can have a U-shape or V-shape requiring, thus, that the ami 118 of the paddle distractor 102, 104 be formed with a complementary shape. To prevent twisting between the paddle distractor 102, 104 and the vessel retractor 200, the channel 208, slidingly receiving the ridge 120 of the arm 118, is configured to prevent rotational motion of the components therebetween. In particular, the channel 208 and the ridge 120 are formed with complementary U- shaped cross-sections or dovetail cross-sections.

[0044] Furthermore, as shown in FIGS. 1 and 3, the slots 206 are formed on the inner faces of the sidewalls 204. Alternatively, as shown in FIG. 3, the outer faces of the sidewalls can be provided with the slots 206. Still another alternative configuration includes the slot 221 formed in the outer face 209 (FIG. 3) of the retractor 200 and a projection 223, which extends from the bottom of the slot 221 and can slide along a recess formed in the opposing surface of the arm 118 (not shown). To assure that the arms 118 and the retractor 200 are rotationally fixed, the projection 223 can be formed with a ridge 225 provided with one of U-, dovetail- and T-shaped cross sections. Accordingly, the arms 118 of the paddle distractors 102, 104 each have a recess (not shown) receiving the projection 223 and having a channel, which is shaped complementary to and receives the ridge 225.

[0045] To provide engagement between the retractor and the distractor provided with the distal bo'dy 206 detachable from the arm 118, the retractor may have projections 231 (FIG. 3) receivable in slots 133 formed either in the inner 114 or outer 112 surfaces of the body 106 (FIG. 2). Alternatively, the slots 133 may be formed within the body and open into its rear side (not shown) to receive respective projections 231 shaped complementary to the surfaces of the slots 231 after the arm(s) 118 has been detached from the body 106.

[0046] To ensure a fixed position between the retractor vessel 200 and distractor 104, 106, each of the arms 118 can be provided with a mechanical means for fixedly engaging the retractor vessel. As shown in FIG. 2, at least one of the opposite sides 113 of the arm 118 may have a spring loaded ball assembly 115 biased upwards and/or downwards to engage a respective detend (not shown) formed in the opposing surface of the slot 206 of the retractor vessel. As long as the surface of the retractor vessel presses against the side(s) 113 of the arm 118, the ball would remain withdrawn allowing, thus, the vessel retractor 200 to slide relative to the arms 118. Once the detent formed on the surface of the retractor vessel 200 reaches the ball assembly 115, the ball of the latter pops up into the detent to stop displacement of the retractor in a desired position.

[0047] It is critical to configure the retractor 200 such that a central channel 211 defined between inner faces of the sidewalls 204 would be shaped and dimensioned to allow numerous end plate preparation instruments to be inserted through this channel into the disc space. If the slots 206 are formed in the inner faces of the sidewall 204, each of them is so configured that inner surfaces 119 (FIG. 1) of the arms 118 lie flush with the inner faces of the sidewalls 204. Hence, the channel 211 is unobstructed and serves as a guide channel for numerous instruments including a spinal implant. Turning momentarily to FIG. 10, to facilitate insertion of various end plate preparation instruments into the disc space, the inner faces of the of the retractor can be provided with guides 304, which direct these instruments through the channel 211 into the disc space.

[0048] Returning to FIG. 3, base wall 202 is provided with an arcuate distal surface 210 projecting into the base wall 202, which arcuate distal surface 210 is provided with a central spike or multiple spikes 212 projecting distally therefrom. The arcuate surface 210 is configured and adapted to cooperate with the arcuate anterior surface of a vertebral body, while spike 212 is provided to engage the vertebral body and prevent relative movement of the vessel retractor 200 with respect to the vertebral body.

[0049] A method according to the present disclosure of using the spinal instrument system 100 according to the present disclosure will now be described with particular reference to FIGS. 4-10. As seen in FIG.4, an upper and a lower vertebral body 300 and 302 respectively, are shown in which a disc space 304 between the vertebral bodies 300 and 302.

[0050] In FIGs. 5 and 6, the body portion 106 of left paddle distractor 102 has been inserted between the upper and lower vertebral bodies 300 and 302 while in a flattened orientation with the rounded upper surface 108 directed toward the center of the disc space (i.e., rotated 90° along a longitudinal axis of the arm 118 as shown in FIG.2). In order to facilitate insertion of the paddle distractors 102 and 104 into the disc space, a quick release handle (not shown) can be coupled to the arm 118. Left paddle distractor 102 is then rotated 90° counter clockwise in order to distract the disc space (i.e., separate the upper vertebral body 300 from the lower vertebral body 302). Left paddle distractor 102 is rotated counter clockwise so that the pointed ridge 116 formed on the planar portion 110 digs into the upper surface of the end plate of the lower vertebral body 302 and so that the rounded upper surface 108 passes smoothly over the lower surface of end plate of the upper vertebral body 300 thus not damaging or digging into the lower surface of the upper vertebral body 300.

[0051] As seen in FIG. 7, the body portion 106 of the right paddle distractor 104 is then inserted into the distracted disc space and then rotated 90° clockwise until the right paddle distractor 104 is in the vertical upright position. With the respective arms 118 of the left and right paddle distractors 102, 104 projecting outwardly from the anterior surface of the vertebral bodies 300 and 302, as seen in FIG. 7, the vessel retractor 200 is operatively coupled to the arms 118. The arms 118 are slidingly received into the slots 206 until the spike 212 of the vessel retractor 200 engages the anterior surface of the lower vertebral body 302 thereby stabilizing the vessel retractor 200 against the anterior face of the vertebral bodies.

[0052] As seen in FIG. 9, with the vessel retractor 200 in place, major blood vessels "V", in particular in the lumbar region of the spine, can be retracted around the vessel retractor 200 thereby providing the orthopedic surgeon with a cleared surgical field in which to operate and whereby the need for a vascular surgeon to manually maintain the major blood vessels "N" retracted during the surgical procedure has been eliminated.

[0053] Turning now to FIG.10, with the vessel retractor 200 in place, the orthopedic surgeon can use a surgical end plate preparation instrument (e.g., a rasp, chisel, box chisel, curette, etc.) inserted through the vessel retractor 200 into the disc space in order to prepare the lower surface of the vertebral body 300 and the upper surface of the lower vertebral body 302 for receipt of a spinal implant (not shown) therein. Furthermore, the retractor vessel 200 may be dimensioned so that it will span multiple vertebral levels to allow the surgeon to access these levels simultaneously for a variety of tasks. For example, a fixation plate 350, as shown in FIG. 15, can be juxtaposed with and attached to outer faces of the vertebra to enhance the stability of the operated motion segment. It is envisioned that a series of surgical rasps, or box chisels, having varying heights can be provided in order to prepare the end plates of vertebral bodies and which varying heights accommodate various locations along the spinal column.

[0054] After the surfaces of the disc space have been prepared, the surgeon inserts a series of surgical trials in order to assess the height, width and depth of the disc space so that a properly sized implant is selected. With the implant inserted into the disc space, the vessel retractor 200 is removed and the quick release handles (not shown) are reattached to the arms 118 of the left and right paddle distractor 102 and 104 in order to facilitate removal of the paddle distractors 102 and 104 therefrom.

[0055] Turning now to FIG. 11 , an alternative embodiment of a vessel retractor according to the present disclosure is generally shown as 400. Vessel retractor 400 includes a side wall 402 having an upper and a lower wall 404 and 406 respectively, which upper and lower walls 404 and 406 are orthogonal to and integrally formed with the side wall 402 and are substantially parallel to one another. The vessel retractor 400 includes a flange 408 formed at a distal end thereof and extending from a distal end of upper wall 404 down a distal end of the side wall 402 and along a distal end of the lower wall 406. A pair of spikes 410 are provided which project from end of the upper wall 404 and the distal end of the lower wall 406 respectively. The spikes 410 are configured and adapted to engage the anterior surface of a vertebral body and thereby stabilize the vessel retractor 400 against the vertebral body. The side wall 402 is provided with a slot 412 having a pair of channels 414 formed along the upper and lower surfaces thereof. The slot 41^"2 is oriented such that the slot 412 extends from the distal surface to the proximal surface of the side wall 402 and is opened on either end. Depending on a specific situation, each half 400 can be used individually. To provide a support for various organs during the spinal surgery and/or a support for the blood vessel, the half 400, if used individually, can have its opposite upper 404 and/or lower 406 walls provided with an extension 411 projecting inwards from the sidewall 402 along with a respective extension of the flange 408. Note that the retractor 200 shown in FIGS. 1 and 3 also can be provided with a flange identical to the flange 408.

[0056] As seen in FIGS. 13 and 14, by providing the slot 412 of the vessel retractor 400 with upper and lower channels 414, a single vessel retractor 400 can be used on either the left or the right paddle distractor 102 and 104 by rotating or inverting the vessel retractor 400 about the slot 412. In addition, vessel retractor 400 provides a surgeon with increased flexibility when positioning the paddle distractors in the disc space because the surgeon does not have to precisely position the location of a first paddle distractor with respect to a second paddle distractor in order to accommodate the vessel retractor. Instead, the surgeon can place the second paddle distractor as close to or as far from the first paddle distractor as needed or desired without worrying about having to align the slots of the vessel retractor with the arms of the paddle distractors.

[0057] As with vessel retractor 200, vessel retractor 400 provides a surgeon with a clear and free surgical field in which to operate. In use, after the pair of paddle distractors have been inserted into place, a first vessel retractor 400 is operatively coupled to the first paddle distractor and a second vessel retractor 400 is operatively coupled to the second paddle distractor such that the upper and lower walls 404 and 406 of the vessel retractor 400 are oriented towards one another. In this manner, as seen in FIGS. 13 and 14, the vessel retractors 400 define an operative space 416 for the surgeon to use in order to introduce surgical instruments and the like. Once again, the major blood vessels are retracted around the side wall 402 of the individual retractor thereby eliminating the need of a vascular surgeon to manually retract the blood vessels from the operative region during the surgical procedure.

[0058] It will be understood that various modifications may be made to the embodiments disclosed herein. It is envisioned that the arms of the paddle distractors can be provided with other means for engaging the slot of the vessel retractor such that the paddle distractor does not rotate once coupled to the vessel retractor. In addition, it is envisioned that the upper surface of the body portion of the paddle distractor can be semi-circular such that the same paddle distractor can be used on either the right or left side of the disc space and such that the paddle distractor can be rotated either clockwise or counter-clockwise without digging into the surface of the vertebral body. Likewise, it is envisioned that a single universal paddle distractor can be used on either side of the disc space and which is configured and adapted to cooperate with a universal slot formed in the vessel retractor. Therefore, the above description should not be construed as limiting, but merely as exemplification of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure.

Claims

WHAT WE CLAIM IS: 1. An instrumentation system for performing a spinal surgery through an anterior, anterolateral, or lateral approach, comprising: at least one distractor removably insertable into a disc space and configured to rotate within the disc space so the disc space is gradually distracted; and a retractor coupled to the at least one distractor upon distraction of the disc space and having an outer surface configured to retract and maintain a blood vessel or other internal structures so as to keep the surgical field during the spinal surgery unobstructed.

2. The instrumentation system of claim 1, further comprising another distractor in addition to the at least one distractor, the retractor having a monolithic body removably mounted to and slidable along the distractors towards anterior faces of adjacent vertebra and configured to abut the anterior faces, end plates of which define the disc space therebetween.

3. The instrumentation system of claim 2, wherein the monolithic body of the retractor is formed with a U cross-section configured by spaced sidewalls and a base wall bridging the sidewalls, each of the sidewalls having respective inner and outer faces and respective proximal and distal sides bridging the inner and outer faces, the distal sides being juxtaposed with the anterior faces of the vertebra to prevent further displacement of the retractor along the distractors, whereas the outer surfaces of the sidewalls each are configured to provide the smooth retraction of the blood vessel or other internal structures, and to maintain retraction of the structures during the spinal surgery.

4. The instrumentation system of claim 3 further comprising a guide assembly located between the inner or outer faces of each of the sidewalls and a respective one of the distractors and including a projection/slot mechanism, wherein the protrusion/detent mechanism has a slot and a projection engageable with one another to provide displacement of the retractor and distractors relative to one another upon distracting the disc space.

5. The instrumentation system of claim 4, wherein the slot is provided on each of the distractors and receives a projection of the guide assembly formed on the sidewalls of the retractor.

6. The instrumentation system of claim 4, wherein the slot of the guide assembly is formed on each of the sidewalls of the retractor and configured to slidably receive the projection, the projection being an arm of a respective distractor extending rearwards from the disc space, the slot having an inner surface extending complementary to and surrounding an outer surface of the arm.

7. The instrumentation system of claim 6, wherein the inner surface of each slot provided in the sidewalls of the retractor has a respective channel configured to slidably engage a ridge formed on the outer surface of the arm of the distractors and to prevent rotational displacement of the distractors and retractor relative to one another.

8. The instrumentation system of claim 4, wherein the sidewalls of the retractor each are formed with a respective slot of the guide assembly extending rearwards from the distal side and either terminating at a distance from the proximal side of or opening into the proximal side of the sidewalls.

9. The instrumentation system of claim 6, wherein the slot of the guide assembly is provided on the inner face of the sidewalls of the retractor.

10. The instrumentation system of claim 6, wherein the slot of the guide assembly is provided on an outer side of the sidewalls of the retractor.

11. The instrumentation system of claim 7, wherein the channels each extend from a respective slot of the guide assembly and have a U cross-section, a dovetail cross section , rectangular cross section, or a T cross-section, the ridge, which is formed on the arm of each distractor, being provided with a cross-section formed complementary to the cross-section of the channel.

12. The instrumentation system of claim 6, wherein each of the slots of the guide assembly is shaped and dimensioned so that when the arm of a respective distractor is received in the slot, an outer surface of the arm lies flush with the inner or outer face of the sidewall of the retractor.

13. The instrumentation system of claim 6, wherein the slot of the guide assembly is provided with a U cross-section or a dovetail cross-section.

14. The instrumentation system of claim 3 , wherein the outer face of the of each sidewall has a top rounded flange extending parallel to the base wall and shaped to guide the retracted blood vessel, or other internal structures, downwards along the outer face.

15. The instrumentation system of claim 3, wherein at least one of the distal sides of the sidewalls and a distal side of the base wall has at least one fastener extending therefrom toward and engaging the faces of the adjacent vertebra so that relative displacement of the retractor and the vertebra is prevented during the spinal surgery.

16. The instrumentation system of claim 14, wherein the distal side of the base wall of the retractor has a rearwardly concave cross section to conform to a shape of the faces of the vertebra.

17. The instrumentation system of claim 2, wherein the retractor includes at least one C-shaped body configured to removably engage the at least one distractor while sliding therealong towards and away from the faces of the adjacent vertebra, the at least one C-shaped body being provided with spaced apart distal and proximal sides defining therebetween oppositely located inner and outer faces of the sidewalls of the retractor, wherein the outer face is shaped to retract and maintain the blood vessel or other internal structures , during the spinal surgery.

18. The instrumentation system of claim 17, wherein the distal side of the retractor has a respective C-shaped flange extending laterally outwards from the sidewall of the at least one C- shaped body of the retractor and abuts the faces of the adjacent vertebra to prevent further displacement of the retractor along the at least one distractor.

19. The instrumentation system of claim 18, further comprising a plurality of fastener^'s extending from the C-shaped flange of the retractor and engaging the faces of the adjacent vertebra to prevent relative rotational motion between the at least one body and the adjacent vertebra during the spinal surgery.

20. The instrumentation system of claim 17, wherein the C-shaped body of the retractor has upper and lower sides coextending with the inner and outer faces between distal and proximal sides, at least one of the upper and lower sides of the retractor extends laterally further than the opposite one of the upper and lower sides, 404 and 406 are the same inwards.

21. The instrumentation system of claim 17, further comprising a guide assembly located between the retractor and the at least one distractor and configured to slidably guide the at least one body of the retractor and the at least one body relative to one another.

22. The instrumentation system of claim 21 , wherein a slot of the guide assembly is provided on either the inner face of or the outer face of the sidewall of the retractor and slidably receives an arm of the at least one distractor, which extends rearwards from the disc space.

23. The instrumentation system of claim 22, wherein the slot has a channel configured to engage a ridge formed on the arm of the at least one distractor as the at least one body slides along the arm to prevent relative rotational motion between the at least one distractor and the retractor.

24. The instrumentation system of claim 23, wherein the ridge and the channel have juxtaposed surfaces extending complementary to one another and formed with a U cross-section, rectangular cross section, or a dovetail cross-section.

25. The instrumentation system of claim 21 , wherein the guide assembly has a slot provided on one of opposite lateral sides of the at least one distractor and slidably engages a projection extending laterally outwards from either the inner or outer surface of the sidewall of the retractor, which opposes the slot as the at least one C-shaped body of the retractor slides relative the at least one distractor.

26. The instrumentation system of claim 17, wherein the retractor has a second C-shaped body cooperating with the other distractor independently from the cooperation between the at least one C- shaped body of the retractor and the at least one distractor.

27. The instrumentation system of claim 2, wherein the at least one distractor is a paddle distractor cooperating with the retractor and having a body formed with: inner and outer surfaces defining therebetween a thickness of the body, and side surfaces bridging the inner and outer surfaces and defining therebetween a height of the body, wherein the height of the body is greater than the width of the body which is configured to be inserted into the disc space in a flattened configuration, in which the inner and outer surfaces are juxtaposed with the end plates of the adjacent vertebral endplates after the body has been inserted into the disc space.

28. The instrumentation system of claim 27, wherein the at least one distractor has an arm dimensioned to have a width substantially equal to the width of the body and extending from the body beyond the disc space.

29. The instrumentation system of claim 28, wherein the arm and the body form a unitary integral structure of the at least one distractor, the arm being dimensioned to have a width substantially equal to the width of the body and providing a slidable support for the retractor.

30. The instrumentation system of claim 28, wherein the arm of the at least one distractor is detachably coupled with the body thereof and detachable therefrom after the at least one distractor has been inserted into and rotated within the disc space.

31. The instrumentation system of claim 28, wherein the arm has at least one projection extending outwards and configured to abut outer faces of the adjacent vertebra in an inserted position of the body, in which the body has penetrated into the disc space at a desired depth, the retractor being configured so that the at least one projection mates with a key surface formed on the retractor and shaped complementary to the at least one projection, as the retractor slides toward the vertebra.

32. The instrumentation system of claim 27, wherein the at least one distractor rotates approximately 90 degrees to displace the vertebra apart at a distance corresponding to the height of the body upon insertion of the body into the disc space in the flattened configuration.

33. The instrumentation system of claim 27, wherein at least one of the side surfaces of the body of the at least one distractor is rounded or slanted, said partially rounded or slanted side surface extends from an edge of one of the inner and outer side surfaces of the body towards the other one of the inner and outer surfaces of the body.

34. The instrumentation system of claim 33, wherein the at least one rounded side surface has a flat interrupting the continuity of the rounded surface.

35. The instrumentation system of claim 33, wherein the other one of the side surfaces of the body is planar and has a pointed projection or a keyed projection extending therefrom to engage a respective endplate of the adjacent vertebra upon rotation of the at least one distractor.

36. The instrumentation system of claim 35, wherein the pointed projection is selected from the group consisting of a pointed rib, at least one spike, at least one cone and a combination of these.

37. The instrumentation system of claim 29, wherein the arm of the at least one distractor has at least one ridge configured to slidably engage the retractor and to prevent rotational motion between the at least one distractor and retractor upon engagement thereof.

38. The instrumentation system of claim 29, wherein the arm of the at least one distractor has a spring-loaded ball assembly including a spring and a ball biased by the spring toward and engaging the retractor so that the retractor and the at least one distractor are locked relative to one another.

39. The instrumentation system of claim 37, wherein the ridge extends along at least a portion of the arm and is narrower than the arm, the arm being configured to have a height smaller than the height of the body.

40. The instrumentation system of claims 39, wherein the ridge has a U cross- section, a rectangular cross-section, a N cross-section, or a dovetail cross-section.

41. The instrumentation system of claim 2, wherein the retractor is configured to provide the surgeon open access to the outer surfaces of the adjacent vertebra, the instrumentation system further comprising a fixation plate guidable through the retractor to be attached to the outer surfaces of the adjacent vertebra, and at least one surgical instrument guided through the retractor into the disc space to prepare the end plates of the adjacent vertebra so as to accommodate a spinal implant.

42. The instrumentation system of claim 41 , further comprising an implant inserter configured to insert the spinal implant through the retractor into the prepared disc space.

43. A kit including a variety of instruments used in a spinal surgery, comprising: at least one distractor configured to penetrate into a disc space, which is defined between adjacent vertebra, and operative to rotate therein so that the adjacent vertebra are displaced from one another and to define a distracted disc space; a retractor removably mounted on the at least one distractor upon distracting the disc space and operative to slide therealong to abut faces of the adjacent vertebra, the retractor having an outer face configured to retract a blood vessel, or other internal structures, around the retractor and maintain the retraction of the blood vessel, or other internal structures; and a plurality of trials configured to be used to access the distracted disc space so as to determine the correct size of a spinal implant.

44. The kit of claim 43, wherein the at least one distractor includes a body having spaced inner and outer surfaces defining a thickness of the body and spaced side surfaces extending between the inner and outer surfaces and defining therebetween a height of the body, wherein the height of the body is larger than the thickness of the body, the body further including an arm extending from the body and beyond the disc space upon insertion of the at least one distractor into the disc space, whereas the distractor is operative to rotate after insertion into the disc space so that the adjacent vertebra are displaced away from one another at a distance corresponding to the height of the body.

45. The kit of claim 44, wherein the retractor is configured to have at least one sidewall cooperating with the arm of the at least one distractor and to slide therealong toward and away from the adjacent vertebra, one of the side surfaces of the body of the at least one distractor being provided with at least one projection configured to engage the end plate of one of the adjacent vertebra upon distraction of the disc space and preventing further rotation of the body relative tot he vertebra, the retractor having a distal wall facing the face of the adjacent vertebra and being formed with a formations configured to penetrate the anterior face and to rotatably fix the retractor to the adjacent vertebra.

46. A method of performing spinal surgery, comprising the steps of: introducing at least one distractor into the disc space between adjacent anterior faces of adjacent vertebra through an anterior, anterolateral, or lateral approach, end plates of the adjacent vertebra define the disc space, the at least one distractor being configured to have a height greater than a thickness; rotating the at least one distractor, thereby displacing the adjacent vertebra away from one another at a distance corresponding to the height of the at least one distractor to distract the disc space; slidably mounting a retractor on and displacing the retractor along the at least one distractor toward the anterior faces of the adjacent vertebra; and retracting a blood vessel, or other internal structures, along an outer surface of the retractor configured so that the blood vessel, or other internal structure, is supported by the outer surface during the spinal surgery.

47. The method of claim 46 further comprising the steps of: anchoring the at least one distractor in one of the end plates of the adjacent vertebra to prevent displacement therebetween during the spinal surgery; and rotatably fixing the retractor to the faces of the vertebrae to prevent relative displacement of the retractor and the vertebrae during the spinal surgery.

48. A method of operating a system of spinal instruments comprising at least one distractor removably insertable into the disc space defined between end plates of adjacent vertebra, and a retractor; the method comprising the steps of: configuring the at least one distractor so that the at least one distractor has a distal body shaped and dimensioned to have a thickness greater than a width; inserting the distractor into the disc space in a flattened orientation so that opposite surfaces of the distal body defining the width thereof face the end plates of the adjacent vertebra; rotating the at least one distractor to displace the adjacent vertebra away from one another at a distance corresponding to the thickness of the distractor, thereby distracting the disc space; providing the retractor with an outer surface shaped and dimensioned to provide a support for a blood vessel, or other internal structure; and mounting the retractor to the at least one distractor and retracting the blood vessel, or other internal structure, around the outer surface of the retractor so as to maintain the blood vessel, or other internal structure while rotatably fixing the at least one distractor and the retractor.

49. The method of claim 48, wherein the step of configuring the distractor includes providing an arm detachably or permanently coupled to the body and having a ridge extending along a portion of and being thinner than the arm.

50. The method of claim 49, wherein the arm of the at least one distractor slidably supports the retractor, the method further comprising the steps of: providing a sidewall of the retractor with a slot having a peripheral surface, and forming a channel in the peripheral surface of the slot, wherein the slot is configured to receive the arm of the distractor and the channel is configured to receive • the ridge of the arm to linearly guide the retractor along the arm toward and away from the anterior faces of the vertebra, the sidewall of the retractor being formed with the outer surface shaped to support the blood vessel, or other internal structures.

51. The method of claim 50, wherein the step of forming the channel includes providing the channel with a cross-section which is complementary to a cross section of the ridge and configured to prevent relative rotation of the retractor and distractor upon engagement of the arm of the distractor within the slot of the sidewall of the retractor.

52. The method of claim 51 , wherein the outer surface of the retractor is provided with an upper rounded, slanted, or curved surface providing a smooth retraction of the blood vessel, or other internal structures.

53. The method of claim 52, wherein the retractor is configured to have an inner peripheral surface dimensioned to guide a plurality of instrument adapted to treat the end plates or dimensionally assess the disc space of the vertebra so as to prepare the disc space for receiving a spinal implant.

54. The method of claim 51 , wherein the retractor is formed as a monolithic U-shaped body or as an assembly having two separate C-shaped bodies.

55. The method of claim 48 further comprising the steps of forming at least one fastener on the body of the distractor and engaging the end plate of one of the vertebra upon distraction of the disc space, thereby fixing the distractor and the engaged vertebra relative to one another, and forming at least one fastener on a distal end of the retractor configured to engage the face of the vertebra, thereby fixing the vertebra and the retractor relative to one another.