WO2011112748A2 - Spinal surgical apparatus and method of treating an abnormally shaped spine - Google Patents

Abstract

A spinal surgical apparatus is described. The spinal surgical apparatus may include a first member having an adjustable length, wherein the first member allows increase in the length thereof but prevents decrease in the length thereof. Optionally, the spinal surgical apparatus may also include a second member allowing rotation in a first rotational direction but preventing rotation in a second rotational direction opposed to the first rotational direction. A method of treating an abnormally shaped spine is also described.

Description

Spinal Surgical Apparatus and Method of Treating an Abnormally Shaped Spine

Cross Reference to Related Applications

[0001] This international patent application claims priority to and benefit from, currently pending U.S. Provisional Patent Application serial No. 61/312,539, filed 10 March 2010.

Technical Field

[0002] Embodiments of the invention pertain to spinal surgery.

Background

[0003] Spinal surgery for conditions such as scoliosis is often performed on children who have not finished growing. Because of normal ongoing growth of the patient, it is sometimes necessary to perform repeat surgeries. Also, treatment of conditions such as scoliosis sometimes requires that previously implanted spinal hardware be adjusted in terms of its anchoring or shape so that treatment can be performed in a gradual manner. Again, this requires the patient to undergo repeated surgeries. Even though the follow-up surgeries may be less traumatic than the original surgery that initially implanted the hardware, it still would be preferable for the patient if such surgeries could be minimized or even avoided altogether.

Summary

[0004] In an embodiment of a spinal surgical apparatus, there may be provided, in any

combination, some or all of the following: a lengthenable first member and/or a rotatable second member. Either of these members may optionally include a ratchet. The first member may include a centrally located extendible member and two ends connected to the extendible member. In some embodiments of such a first member, the first end and the second end may have respective longitudinal axes that may optionally be collinear with each other. Optionally, the two ends may be detachable from the extendible central member, even after the ends are implanted in a patient, so that the extendible member may be replaced with a differently- sized extendible member. It is possible to use a first member either on one side of the spine or on both sides of the spine. It is possible that either a first member or a second member may be connected to a rib, or to a pedicle screw, at one end or at the other end of the member, in any combination. The first member and/or the second member may be a passive mechanical apparatus that permits motion in one direction and resists motion in the opposite direction. The positions at which the apparatus resists motion may be continuously variable or may comprise a finite number of discrete positions. In some embodiments members which operate with a finite number of discrete positions may still permit bidirectional motion in the small distance between adjacent discrete positions. Also, in some embodiments the first member and/or the second member may include a release element that may be selectively actuated to allow motion in the direction that motion is usually not permitted.

[0005] In some embodiments a pedicle screw may be provided whose head is rotatable with respect to its shaft even when the spinal rod is tightened into the pedicle screw head. An apparatus that incorporates such a pedicle screw may comprise a spinal rod that, when the apparatus is tightened, bears against the bottom of a U-shaped groove in a pedicle screw head, with or without bearing against the screw head. In some alternative embodiments, the pedicle screw may comprise separate but interconnected screw head and screw shaft.

[0006] An embodiment of treating an abnormally shaped spine in a patient may include

implanting a first member and a second member on opposite sides of the spine. Optionally, implanted spinal hardware may be adjusted at some time after the implantation, merely by manipulating the patient' s body in an appropriate manner, without requiring the patient to undergo additional surgery and/or without requiring puncturing of the patient's skin. Such adjustment may cause the first member to lengthen and/or the second member to rotate. Embodiments of the method also include the corresponding methods of surgery and treatment. In still other embodiments, it is possible that the members (first and/or second) may be adjusted during subsequent surgical procedures. In an embodiment of the method, it is possible that a follow-up surgery may be performed, during which the centrally-located extendible member may be replaced with a differently-sized extendible member. For example, by disconnecting the previously-implanted ends from the extendible member and re-connecting them to a new differently-dimensioned extendible member. In embodiments of the method, it is possible to perform distraction during implantation of any of the described apparatus. [0007] Generally, in one aspect a spinal surgical apparatus is provided that includes a first member and a second member. The first member has an adjustable length, allows increase in the length, and has at least one stop that at least selectively prevents decrease in the length. The second member allows rotation in a first rotational direction but at least selectively prevents rotation in a second rotational direction that is opposed to the first rotational direction.

[0008] In some embodiments the first member includes a ratchet to control motion in a linear direction.

[0009] In some embodiments the second member includes a ratchet to control motion in the first rotational direction.

[0010] In some embodiments the first member has a first end and a second end. In some versions of those embodiments at least one of the first end and the second end is hingedly attached. In some versions of those embodiments at least one of the first end and the second end is hingedly attached and fixable at a desired hinged orientation.

[0011] In some versions of the embodiments having a first end and a second end, the

apparatus further includes a pedicle screw configured to attach to a vertebra and receive at least one of the first end and the second end of said first member. In some versions of those embodiments the pedicle screw includes a head and a shaft and the head is rotatable with respect to the shaft after implantation of the shaft. Optionally, the head may be a polyaxial head movably attached over a screw head attached to the shaft. In other embodiments the head may be a screw head. The screw head may optionally include a plurality of interior splines interfacing with a plurality of exterior splines of the shaft

[0012] In some embodiments the first member has a first end and a second end, and at least one of the ends is removably attached to an adjustment mechanism of the first member.

[0013] In some embodiments the second member has a first end and a second end, and at least one of the ends is configured to be received by a pedicle screw.

[0014] In some embodiments the first member is lengthenable after surgical implantation in a patient by manipulating the patient non- surgically. [0015] In some embodiments the second member is rotatable after surgical implantation in a patient by manipulating the patient non- surgically.

[0016] Generally, in another aspect, a method of treating an abnormally shaped spine in a patient is provided. The method includes the steps of surgically implanting a first member into the patient adjacent a concave portion of the spine and surgically implanting a second member into the patient adjacent a convex portion of the spine. The first member may have an adjustable length, allow an increase in the length, and include at least one stop that selectively prevents decrease in the length. The second member may allow rotation in one rotational direction but at least selectively prevent rotation in an opposed direction.

[0017] Generally, in another aspect, a spinal surgical apparatus is provided that includes a first member comprising an extendible mechanism, a first end extending from the extendible mechanism, and a second end extending from the extendible mechanism. The first end has a first end axis and the second end has a second end axis. The first end axis and the second end axis optionally coincide with each other. The apparatus also includes a first pedicle screw which grasps the first end of the first member. The pedicle screw optionally allows for rotation of the first end about an axis generally defined by a shaft of the pedicle screw.

[0018] Generally, in another aspect, a method of treating an abnormally shaped spine in a patient is provided. The method includes the steps of implanting, during a first surgery, a first member in the patient. The first member includes a first extendible mechanism, a first end detachably connected to the first extendible mechanism, and a second end detachably connected to the first extendible mechanism opposite the first end. The method further includes allowing or causing the first member to lengthen after the first surgery and, during a subsequent surgery: removing the first extendible mechanism while leaving at least one of the first end and the second end in the patient's body; and connecting a second extendible mechanism to the first end and the second end.

[0019] Generally, in another aspect, a spinal surgical apparatus is provided that includes a first extendible mechanism, a first end detachably connectable to the first extendible mechanism, a second end detachably connectable to the first extendible mechanism opposite the first end, and a second extendible mechanism that is detachably connectable to the first end and the second end. The second extendible mechanism has at least one dimension different from a corresponding dimension of the first extendible mechanism. [0020] Generally, in another aspect, a spinal surgical apparatus is provided that includes a screw shaft having external threads, a screw head integrally connected to the screw shaft, and a polyaxial head partly surrounding the screw head and movable with respect to the screw head. The polyaxial head has a recess for accepting a spinal rod. The screw head has at least a portion that is generally externally spherical and the polyaxial head has a portion that is generally internally spherical complementary to the screw head spherical portion. The apparatus also includes a rod that is fixedly receivable in the polyaxial head. When the rod is held tightly in the polyaxial head, the screw head is movable with respect to the polyaxial head.

[0021] Generally, in another aspect, a method of treating an abnormally shaped spine in a patient is provided. The method includes the steps of implanting, during a first surgery, a first member in the patient. The first member may include a first extendible mechanism connected to a first end and a second end connected to the first extendible mechanism generally opposite the first end. The method further includes the steps of connecting the first end to a first vertebra or rib; connecting the second end to a second vertebra or rib; and after the first surgery, allowing or causing the first member to lengthen by applying forces or motions to the patient non-surgically.

[0022] Generally, in another aspect, a spinal surgical apparatus is provided that includes a first member having an extendible mechanism and a first end extending from the extendible mechanism and a second end extending from the extendible mechanism, wherein at least one of the first end and the second end is a spinal rod; and a pedicle screw which grasps the spinal rod. Optionally, the pedicle screw may include a head that is rotatable with respect to a shaft thereof after implantation of the screw.

[0023] Generally, in another aspect, a spinal surgical apparatus is provided that includes a first member comprising an extendible mechanism and a first end extending from the extendible mechanism and a second end extending from the extendible mechanism, wherein at least one of the first end and the second end is a spinal rod having a means for grasping a rib. Optionally, the means for grasping a rib may enable pivotable movement of the spinal rod relative thereto.

Brief Description of the Illustrations

[0024] Embodiments of the invention are further described in the following illustrations. [0025] Figure 1 illustrates schematically a scoliotic spine, viewed from the posterior.

[0026] Figure 2 is a sectional view of a prior art pedicle screw.

[0027] Figure 3 illustrates an adjustable corpectomy device.

[0028] Figure 4A is an illustration, looking at the posterior of a spine, of an apparatus of an embodiment of the invention, involving connections of the apparatus to pedicle screws, before expansion of the apparatus.

[0029] Figure 4B is an illustration of the apparatus of Figure 4A after expansion of the

apparatus.

[0030] Figure 5A is an illustration of a linear ratchet device.

[0031] Figure 5B is a perspective illustration of a second embodiment of a first member.

[0032] Figure 5C is a section of Figure 5B taken along the line 5C-5C of Figure 5B.

[0033] Figure 5D is a perspective view of only some components of the second embodiment of the first member of Figure 5B.

[0034] Figure 5E is a perspective view of only certain components of the second embodiment of the first member of Figure 5B, namely the inner cage and the ring.

[0035] Figure 5F is a perspective view of only the inner cage component of the second

embodiment of the first member of Figure 5B.

[0036] Figure 5G is a perspective view of half of the ring component of the second

embodiment of the first member of Figure 5B.

[0037] Figure 6A is an illustration of a rotary ratchet that includes teeth on a perimeter of a disc, and a pawl.

[0038] Figure 6B is an illustration of a rotary ratchet involving ratcheting comprising certain geometries on the faces of two interacting discs. [0039] Figure 7 is an illustration, looking at the posterior of a spine, of an apparatus of an embodiment of the invention, involving connections of the apparatus to ribs, before expansion.

[0040] Figure 8A shows a prior art pedicle screw in which the spinal rod presses on the

spherical head of the screw.

[0041] Figure 8B shows a pedicle screw of an embodiment of the invention, in which there is a gap between the spinal rod and the spherical head of the screw.

[0042] Figure 9A is a sectional view of a pedicle screw of an embodiment of the invention gripping a rod.

[0043] Figure 9B is a view similar to Figure 9A with some parts removed for clarity.

[0044] Figure 9C is a section view taken along line 9C-C in Figure 9B, showing spline

interactions.

[0045] Figure 9D shows a sectional view of a pedicle screw of an embodiment of the

invention gripping a rod.

[0046] Figure 10 is a three-dimensional exploded view of a screw shaft and a spherical head of the embodiment of the pedicle screw of Figure 9 A, illustrating spline interactions.

[0047] Figure 11 is a three-dimensional perspective view of a third embodiment of a first member. The first member includes two different extendible members, each of which can accept the same end pieces.

[0048] Figure 12A is a sequence of views of the third embodiment of the first member of

Figure 11. The views illustrate use of an extendible member having demountable end pieces, and replacement of the extendible member with a larger extendible member, connecting to the same end pieces.

[0049] Figure 12B is the same sequence as Figure 12A, shown in cross-section.

[0050] Figure 13 is an anterior-posterior view showing the use of extendible members on both sides of a slightly deformed spine. [0051] Figure 14A is an illustration, looking at the posterior of a spine, of an apparatus of an embodiment of the invention, involving connections of the apparatus to pedicle screws, before expansion of the apparatus. The apparatus includes a fourth embodiment of the first member.

[0052] Figure 14B is an illustration of the apparatus of Figure 14A after expansion of the apparatus.

[0053] Figure 15 is an illustration of a sagital view of the fourth embodiment of the first member adjacent a spine.

Detailed Description

[0054] Embodiments of the invention may further be understood with reference to Figure 1, which illustrates the anatomical situation of a typical scoliotic spine, in which some vertebra 10 are displaced from a normal position at least in a lateral direction. Figure 1 is a view from the rear, and in this illustration vertebrae 10 are displaced to the patient's right. At the extreme of the abnormal displacement, there is, as labeled in Figure 1, a convex portion 40 and a concave portion 50 opposed to the convex portion 40.

[0055] Figure 2 illustrates a typical prior art polyaxial pedicle screw. In such a typical

pedicle screw, when the setscrew 31 presses against the spinal rod 29, the spinal rod 29 in turn presses on the at least partially spherical screw head 4 which in turn presses the screw head 4 against the interior surface of the polyaxial head 5, thereby locking the position of the screw shaft 1 with respect to the polyaxial head 5.

[0056] Figure 3 is an illustration of a corpectomy device that is lengthenable.

[0057] Referring now to Figure 4A and 4B, it is illustrated that embodiments of the invention may comprise a first member 100 implanted along a patient's spine. Figure 4A is an illustration prior to expansion, and Figure 4B is an illustration after expansion.

[0058] The first member 100 may comprise an extendible mechanism 120 which further may have coupled to it a first end 130 and a second end 140 generally opposed to the first end 130. Such a device may be ratchetable for the described displacement. As illustrated in Figures 4A and 4B, the ends 130, 140 may be rods that are receivable in pedicle screws. The pedicle screws may be, for example, any of the various pedicle screws described herein. For example, the pedicle screw associated with first end 130 may be a first of the pedicle screws described herein and the pedicle screw associated with second end 140 may be a second of the pedicle screws described herein. Similarly, other pedicle screws in the Figures that are depicted but unlabeled may optionally be any of the various pedicle screws described herein. A specific possible arrangement may be that first end 130 may have a first longitudinal axis, and second end 140 may have a second longitudinal axis, and the first longitudinal axis and the second longitudinal axis are collinear with each other.

[0059] The first member 100 may be such that if force or motion is imposed such as to

increase the length of the member 100, such lengthening occurs, but if a compressive force is applied to the first member 100, the member 100 experiences a stopping point beyond which the member 100 does not compress or shorten to any significant extent. The extendible mechanism 120 further may be such that when the extendible mechanism 120 extends, it retains its configuration at the maximum extension that it has experienced. It is also possible that the extendible mechanism 120 may be such that if it is extended from an initial position to a more-lengthened position, the extendible mechanism 120 retains its configuration at an extension which is more extended than its initial configuration. It is possible that such resistance to compression may occur at any one of an infinite number of positions

(continuously variable) such as gripping by friction on the surface of a smooth rod.

Alternatively, it is possible that the extendible mechanism 120 may have increments of acceptable length positions, such that if the extendible mechanism 120 is lengthened, it can slip back to the nearest incremental stopping position and thereafter resists further compression. Alternatively, the member 100 may be lengthenable in a continuous manner and may experience no slip-back at all.

[0060] An example of ratchet device for governing the length of member 100 is illustrated in

Figure 5A. As illustrated, such a ratchet device may comprise a rack and a pawl 520 engageable with teeth 510 of the rack. The teeth 510 may have a preferred direction as illustrate in the example of Figure 5A Such a ratchet device may be placed, in whole or in part, for example, interiorly of extendable mechanism 120. For example, the teeth 510 may be placed on an exterior surface of the upper half of extendable mechanism 120 and one or more pawls 520 may be placed on an interior surface of the lower half of extendable mechanism 120. [0061] A second embodiment of first member 1100, which is based on the design of a corpectomy device, is illustrated in Figures 5B through 5G. First rod end 1130 and second rod end 1140 may be connected to an extendible device 1160 to form first member 1100. An example of such a corpectomy device is the X-POD sold by Integra Spine (formerly Theken Spine) (Akron, OH and Plainsboro, NJ). Other examples of such a corpectomy device are described in Patent No. 7,544,208, U.S. Patent Application Serial No. 12/202,878, and U.S. Patent Application Serial No. 11/327,621. The preceding patent (7,554,208) and patent applications (12/202,878 and 11/327, 621) are hereby incorporated by reference. As illustrated, first end 1130 may have a first longitudinal axis, and second end 1140 may have a second longitudinal axis. The first longitudinal axis and the second longitudinal axis are optionally collinear with each other. Alternatively, it would also be possible to use any of various other types of extendable devices that allow adjustment of the length of two rods. For example, it would be possible to use a device as described in published US Patent Application 2009/0204156 (Automatic Lengthening Bone Fixation Device), which is incorporated herein by reference.

[0062] In the device as illustrated in Figures 5B through 5G, there is an inner cage 1162 received within an outer cage 1164. Inner cage 1162 and outer cage 1164 may be generally cylindrical and may be coaxial with each other. On an external surface of the inner cage 1162 there may be provided at least one or a plurality of helical grooves 366. There also may be provided, trapped within the outer cage 1164, a rotatable ring 1168 whose interior has helical features 1169 that engage the helical grooves 1166. As a result, translation of the inner cage 1162 relative to the outer cage 1164 causes rotation of the ring 1168. On an external surface of ring 1168 there may be provided teeth 1172 or similar features that can be engaged to stop rotation of ring 1168. Stoppage of rotation of ring 1168 in turn causes stoppage of translation of inner cage 1162 with respect to outer cage 1164.

[0063] Associated with outer cage 1164 may be a locking component 1176 that in certain positions engages teeth 1172 of ring 1168 so as to prevent rotation of ring 1168 and thereby prevent translation of inner cage 1162 with respect to outer cage 1164. Locking component 1176 may be movable between a locking position and a non-locking position and may be spring-biased to a locking position. It is further possible that even when locking component 1176 is in its locking position, it only locks against motion in one direction, while motion in the other direction is permitted. For example, the apparatus may be such that when locking component 1176 is in the locking position there is locking so as to resist compression or shortening of the device. On the other hand, if a lengthening motion or tensile force is applied to the device, such motion disengages teeth 1172 of ring 1168 from locking component 1176, thereby permitting rotation of ring 1168 and permitting translation of inner cage 1162 away from outer cage 1164. This may occur, for example, if teeth 1172 only engage locking component 1176 for force applied compressively (bringing inner cage 1162 and outer cage 1164 towards each other) and do not engage locking component 1176 for force that tends to move inner cage 1162 away from outer cage 1164. The teeth 1172 of ring 1168, and the complementary features of locking component 1176, could be shaped to provide slippage in one direction and not the opposite direction. There may also be provided slack space that allows ring 1168 to move away from locking component 1176 and thereby disengage teeth 1172 from locking component 1176 when inner cage 1162 and outer cage 1164 are moved away from each other. In such a device there are a finite number of discrete positions in which inner cage 1162 can lock relative to outer cage 1164. This may be due to the constraint between linear displacement of inner cage 1162 relative to outer cage 1164 and rotation of ring 1168 and/or because of the discreteness of teeth 1172 on ring 1168.

However, the number of those discrete positions is rather large and the increments between those positions is fairly fine, compared to the situation that might occur for a conventional rack and pawl (Figure 5A) for comparable overall dimensions.

[0064] Figure 14A is an illustration, looking at the posterior of a spine, of an apparatus of an embodiment of the invention, involving connections of the apparatus to pedicle screws, before expansion of the apparatus. Figure 14B is an illustration of the apparatus of Figure 14A after expansion of the apparatus.

[0065] The apparatus includes a fourth embodiment of the first member 3100 having an extendable mechanism 3120. A hinge 3123 is provided on a first end of the extendable mechanism 3120 and is coupled to a first end 3130. Similarly, a hinge 3124 is provided on a second end of the extendable mechanism 3120 and is coupled to a second end 3140. The hinges 3123 and/or 3124 may be selectively or permanently locked in some embodiments to fix the angular displacement of respective of ends 3130 and/or 3140 to a desired angular displacement. In some embodiments the hinges 3123 and/or 3124 may be selectively or permanently unlocked. The lockable and/or unlockable hinges 3123 and/or 3124 may in some embodiments enable adjustability for kyphosis and/or allow correction in the sagittal plane as the spine lengthens. For example, in some embodiments the hinges 3123 and/or 3124 may enable movement of the ends 3130 and/or 3140 generally along the sagittal plane only. In some embodiments the hinges 3123 and/or 3124 may allow rotation or advancement in one direction but prevent rotation or advancement in the opposite direction. Such a device may optionally be ratchetable for the desired angular rotation.

[0066] Adjacent a portion of the first end 3130 is a rod 3136 that is coupled to an opposite side of the spine than first end 3130 and that utilizes pedicle screws for attachment to the spine. A cross connector 3133 extends between the first end 3130 and the rod 3136. The rod 3136 and cross connector 3133 may in some embodiments strengthen first end 3130 and/or prevent or minimize the risk of tilting of a patient's shoulders with growth. Similarly, a rod 3146 is coupled to an opposite side of the spine than the second end 3140 and is adjacent to the second end 3140. The rod 3146 is attached with pedicle screws and is attached to a cross connector 3143 that is also attached to second end 3140. The rod 3146 may similarly strengthen second end 3140 and/or minimize the risk of shoulder tilt in some embodiments.

[0067] In other embodiments a rod and cross connector may only be provided in combination with one of first end 3130 and second end 3140. Also, in other embodiments, the rods 3136 and/or 3146 may be alternatively connected utilizing other connection structure such as, for example, hooks or clamps. Also, in other embodiments the rods 3136 and/or 3146 may be non-parallel with ends 3130 and/or 3140.

[0068] Figure 15 is a sagittal view of the fourth embodiment of the first member 3100

adjacent a spine. The first end 3130 has been rotated about hinge 3123 such that it is not collinear with extendable mechanism 3120 and is not collinear with the second end 3140. Similarly, second end 3140 has been rotated about the hinge 3124 such that it is not collinear with extendable mechanism 3120 and is not collinear with the first end 3130. As discussed, the first end 3130 and/or the second end 3140 may optionally be locked in position in some embodiments and unlocked in other embodiments. The first member 3100 may be attached to the spine with the first end 3130 and/or second end 3140 non-collinear with one another and/or non-collinear with the extendable mechanism 3120. Optionally, the hinges 3123 and/or 3124 may allow rotation or advancement in one direction but prevent rotation or advancement in the opposite direction. For example, hinge 3123 may allow rotation in a first direction but prevent rotation in a generally opposite second direction and hinge 3124 may allow rotation in the second direction but prevent rotation in the first direction. First member 3100 is not depicted attached to the spine or a rib in Figure 15, but it is understood that first member may be attached to a spine and/or a rib as desired.

Second member

[0069] Referring again to Figures 4A, 4B, 14A, and 14B embodiments of the invention may comprise a second member 200. The second member 200 may comprise a first end 230, and a second end 240, and a hinge 220 between the two ends 230, 240. Optionally, the hinge 220 may be located generally at the apex of the concave portion of the spine. The hinge 220 may allow rotation or advancement in one direction but prevent rotation or advancement in the opposite direction. Such a device may optionally be ratchetable for the described angular rotation. Either or both of the first end 230 and the second end 240 may comprise a rod receivable in a pedicle screw. Alternatively, either or both of first end 230 and second end 240 may engage with or grip a rib.

[0070] It is further possible that the second member 200 may have increments of acceptable angular positions and may have stops at those positions, such that if the member is rotated in the permitted direction, it can slip back to the nearest incremental rotational stop position and thereafter resists further rotation in the non-permitted direction. Alternatively, the member 200 may be rotatable in a continuous manner, experiencing no slip-back at all.

[0071] An example of ratchet device for angular rotation is illustrated in Figure 6A. As illustrated, such a ratchet device may comprise a disc having teeth 610 on a circumference thereof. It is possible although not necessary that the teeth 610 may have an orientation that is oriented asymmetrically with respect to a radial line so as to be oriented toward one direction of rotation and away from the opposite direction of rotation. Such a device may further comprise a pawl 620 engageable with the teeth 610 to prevent rotation in the non- desired direction.

[0072] Yet another type of ratchet device for angular rotation is illustrated in Figure 6B. As illustrated, such a ratchet device may comprise a disc 670 facing another disc 672, and there may be teeth 680 on the facing surfaces of one or both discs. Discs 670, 672 may optionally be coaxial with each other. Teeth 680 may optionally be shaped so as to preferentially permit one direction of rotation and resist the opposite direction of rotation of discs 670, 672 relative to each other. [0073] It can be noted that devices described so far, i.e., the first member 100 and the second member 200, are passive mechanical devices. They do not generate any force, but rather they merely resist certain forces or motions under certain conditions and allow certain other motions under certain other conditions.

End anchor feature

[0074] Although ends 130, 140, 230, 240 have been illustrated as being spinal rods

receivable in pedicle screws, that is not the only possibility. For example, another alternative is available given that scoliosis often involves at least partially the thoracic region of the spine. In the thoracic region, the vertebrae 10 have ribs extending laterally from them.

Accordingly, it is possible that an end 130, 140 of the first member 100 may comprise a hook or gripping means 500 suitable to grip a rib. Such gripping may be done near the junction between a rib and a vertebra. There may be any desired combination of an end attaching to a pedicle screw, or an end that grips a rib, or both. Gripping of a rib by gripping means 500 is illustrated in Figure 7. Similarly, an end 230, 240 of the second member 200 may comprise a hook or gripping means 500 suitable to grip a rib. Such gripping may be done near the junction between a rib and a vertebra. There may be any desired combination of an end attaching to a pedicle screw, or an end that grips a rib, or both. In embodiments of the invention that involve grasping a rib, the device may comprise any of a variety of hooks, clamps and/or other devices. It is also possible that the rib gripping means 500 may in some embodiments be rotatable with respect to the first member 100 or the second member 200.

[0075] The first member 100 and/or the second member 200, as described herein, may be passive mechanical devices. Such passive mechanical devices change their configuration or dimension in the permitted direction and resist any change in the non-permitted direction, but do not actively generate force or motion and do not receive power from any external source. In other embodiments it would be possible to use some form of motorized device for either linear extension (corresponding to first member 100) or rotation (corresponding to second member 200). Such devices have been known to operate by transmitting an electrical or magnetic or electromagnetic signal or coupling through the intact skin without an incision or puncture. Such a device would typically comprise a motor or some sort of actuator. Swivelable pedicle screw

[0076] In connection with either the first member 100 or the second member 200, there may be provided a polyaxial pedicle screw that permits rotation of the members 100, 200 relative to the screw shaft even after the apparatus has been tightened so that the polyaxial head firmly grasps the members 100, 200.

[0077] For some embodiments, as change of position occurs in the first member 100 and/or the second member 200, if either of those members 100, 200 is attached to a pedicle screw, it may be necessary for there to be a change in the position of the member 100, 200 relative to the pedicle screw. This change may be required after the apparatus has been in the patient for some time, in which situation the shaft of the pedicle screw may have become firmly integrated with bone. If the shaft of the screw is embedded immovably in bone, which is what is generally desired, then it may be necessary for some part of the remainder of the assembly to move relative to the screw shaft. For example, it may be necessary for part of the assembly to rotate around the axis of the screw shaft. If the spine is becoming generally straighter as a result of the treatment or natural growth, or both, such rotation may be desired and/or required.

[0078] An embodiment of the invention that can provide such freedom is illustrated in Figure

8B. In a conventional polyaxial screw, as illustrated in Figure 8 A, upon tightening, the spinal rod 29 bottoms against the top of the screw head 8 which is at the end of the screw shaft 1. This locks all of the components involved, against all degrees of freedom of motion.

[0079] In the embodiment of the invention illustrated in Figure 8B, the spinal rod 29 bottoms against the U-shaped groove 6, which provides for tight locking of the spinal rod 29 with respect to the polyaxial head 5. However, the dimensions of the various components are chosen such that even in a tightened condition, the spinal rod 29 does not contact the screw head 8. This allows continued freedom of motion for all degrees of freedom associated with the seating of the screw head 8 within the polyaxial head 5. In particular, it allows rotation of the first member 100 or the second member 200 with respect to the screw shaft 1. This design provides the desired ability that after the setscrew 31 has been tightened, the polyaxial head 5 is able to rotate around the lengthwise axis of the screw shaft 1. This design also allows the polyaxial head 5 to tilt in all of the various other directions with respect to the screw shaft 1 even after everything is tightened. [0080] Referring now to Figures 9A-9C and 10, there is illustrated yet another embodiment of the invention. This embodiment allows essentially only one degree of freedom of motion with respect to the screw shaft 901, which is a more restricted form of motion than was allowed by the embodiment illustrated in Figure 8B. In this embodiment, there may be provided, as separate parts, a screw shaft 901 and a screw head 910. The screw head 910 may be at least partly spherical on its exterior surface. Internally, the screw head 910 may comprise a cavity 912, and screw shaft 901 may comprise an end feature 902 which fits into cavity 912 with certain constraints. The interrelationship between the cavity 912 and the end feature 902 of screw shaft 901 may be such that screw head 910 is permitted to rotate, within a limited range, with respect to screw shaft 901.

[0081] With continued reference to Figures 9A-9C and 10, the end feature 902 of screw shaft

901 may have, in cross-section perpendicular to a long direction of screw shaft 901, a screw head spline shape having external spline teeth 906. Similarly, the cavity 912 in screw head 910 may have a cavity spline shape having internal spline teeth 916. The screw head spline shape and the cavity spline shape may interact so that the screw head 910 is connected to screw shaft 901 firmly enough to prevent "rocking" of the screw head 910 with respect to the screw shaft 901. In order to prevent "rocking", dimensions may be chosen so that the outer diameter 941 of the spline teeth 906 on the screw shaft end is a close fit with the

corresponding inside diameter 942 of the cavity in the screw head 910. Similarly, the inside diameter 932 of the internal spline teeth 916 inside the cavity 912 in the screw head 910 may be a close fit with the corresponding dimension 931 on the end feature 902 on the end of screw shaft 901. However, in the circumferential direction with respect to rotation around the long direction of screw shaft 901, there may be gaps such that some amount of relative rotation is possible between the screw shaft 901 and the screw head 910.

[0082] With the illustrated design, it is possible for the screw head 910 to transmit torque to the screw shaft 901, if the respective splines are rotationally oriented relative to each other such that the respective spline teeth 906, 916 rotationally contact each other and transmit torque from the screw head 910 to the screw shaft 901 in the appropriate direction. This can occur for screwing the screw into bone. In the event that the screw is twisted in the reverse direction such as for backing the screw out, the spline teeth 906, 916 also would rotationally contact each other so as to transmit torque from the screw head 910 to the screw shaft 901 in the reverse direction. [0083] In this approach, the spinal rod tightens down against the screw head 910, which locks the screw head 910 with respect to all degrees/directions of rotation of the sphere itself.

Then, separately, rotation is provided around the axis of the screw shaft 901 via the interface between screw head 910 and screw shaft 901. This is because the screw shaft 901 is a physically separate part from the screw head 910. The screw shaft 901 would be connected to the screw head 910 with some degree of constraint and yet some degree of looseness as described herein.

[0084] The screw head 910 may be attached to the screw shaft 901 such that movement of the screw head 910 along a vertical axis of the screw shaft 901 is restrained. For example, in some embodiments the screw head 910 may be snapped onto screw shaft 901 such that once snapped on, removal of the screw head 910 is restricted. For example, an interior portion of the screw head 910 proximal the opening of cavity 912 may have stop structure extending interiorly therefrom that engages stop structure extending exteriorly from screw shaft 901. Also, for example, in some embodiments a clip may be provided that engages a recess in screw head 910 and/or polyaxial head 5 and also engages a recess in screw shaft 901 to thereby fix the vertical position of screw head 910 relative to screw shaft 901.

[0085] Referring to Figure 9D, a sectional view of another embodiment of a pedicle screw is shown gripping a rod 29. The pedicle screw includes a screw head 91 OA that is semi- spherical in shape and includes a cavity that receives screw shaft 901 A. Optionally, the cavity of the screw head 91 OA may have interior spline features that interact with

corresponding exterior spline features of the portion of the screw shaft 901 A received therein. The screw shaft 901 A includes a recess 907 therein that is keyed to interface with a driving mechanism such as a multi-sided driving bit. Extending upwardly from the recess 907 is an interiorly threaded section 908 that threadedly receives a portion of a set screw 922. Set screw 922 includes a flange portion that engages screw head 91 OA and restricts vertical movement thereof and also includes a bulbous extension that engages the rod 29. The bulbous extension may optionally include a plurality of recesses therearound to facilitate screwing of the set screw 922 into the threaded section 908.

[0086] The pedicle screw of Figure 9D may be installed by driving screw shaft 901 A into bone utilizing recess 907. The screw head 91 OA and polyaxial head 5 A may then be placed over screw shaft 901 A. The set screw 922 may then be received in threaded section 908 to thereby vertically restrain screw head 91 OA and polyaxial head 5 A. The rod 29 and larger set screw above the rod 29 may then be installed. In alternative embodiments the set screw 922 may be cohesively and integrally formed with the screw shaft 901 A and include driving structure integrated therein. In some of those embodiments the screw head 91 OA may be sized and configured so that it may be placed over the screw shaft 901 A from the bone engaging end thereof until it engages set screw 922. The screw shaft 901 A, with the screw head 91 OA attached, may then be driven into bone. The polyaxial head 5 A may be attached prior to driving the screw shaft 901 A into bone in some of those embodiments and/or may be configured for attachment to the screw head 91 OA after driving the screw shaft 901 A into bone in other of those embodiments. Although various structures and methods for restraining vertical movement of a screw head that is separate from a screw shaft have been described herein, it is understood that additional or alternative structure and/or methods may be utilized in alternative embodiments.

[0087] It can be appreciated that for some embodiments of the first member described herein, the required range of motion (change of angular position of the screw head relative to the screw shaft) is not likely to be very large. The ends of the first member 100 would be attached to vertebrae that are not severely displaced from normal orientation, meaning that the growth rod mostly lengthens and has little need for change of angle.

[0088] For some embodiments of the second member, the required amount of rotation may be greater than what is required with the first member. However, the rotation needed would still be less than the worst angle of scoliosis. Even if the spine were perfectly straightened from its scoliotic configuration, such angular change would not be larger than the maximum angle of the scoliotic deviation of the spine prior to treatment. If the improvement to the scoliosis is less than perfect correction, then the angular change would be less.

[0089] Other additional features may be added. For example, it would be possible to provide a snap-in or lock- in feature so that when the screw shaft 901 is inserted into the cavity 912 in the screw head 910, the screw shaft 901 becomes captured and stays in the cavity 912. Also, for example, it would also be possible to provide a spring-like centering feature so that, in the absence of any externally imposed angular position, the spline on the screw shaft 901 and the spline on the interior of screw head 910 sphere tend to assume an angular position as illustrated in Figure 9C. In other words, a position such that spline teeth 906 are located, in an angular sense, midway between spline teeth 916. Surgical Method

[0090] Embodiments of the invention may also include a surgical method. A surgical

method embodiment may comprise attaching the first end 130 of the first member 100 to a first vertebra and attaching the second end 140 of the first member 100 to a second vertebra, wherein the first vertebra and the second vertebra are separated by at least one vertebra having no connection to the first member 100. Such attachment may be achieved, for example, through the use of pedicle screws screwed into appropriate vertebrae.

[0091] It is possible that both ends 130, 140 of the first member 100 may be attached to pedicle screws as described. It is alternatively possible that an end of the first member 100 could involve grasping a rib using a hook, clamp, or other device, rather than attaching to a pedicle screw that is screwed into a vertebra. It is possible that both ends of the first member 100 could involve grasping ribs. It is possible that one end of the first member 100 could screw into a pedicle screw and the other end could clamp around a rib.

[0092] In some embodiments of the invention, there may be provided the second member

200. It is possible that ends 230, 240 of the second member 200 may be attached to a vertebra using a pedicle screw, or may be attached to a rib using a hook, clamp or similar device, or any combination thereof. It is further possible that the hinge region 220 of the second member 200 may optionally be at least loosely attached to some portion of the spine.

[0093] Referring now to Figures 11 and 12, in an embodiment of the invention, there may be provided a first member 2100 comprising extendible mechanism 2120 A which further may have coupled to it a first end 2130 and a second end 2140 generally opposed to the first end 2130. Ends 2130, 2140 may be such that first end 2130 and/or second end 2140 are removably connected to extendible mechanism 2120A. There may further be provided a variety of sizes of extendible mechanism. For example, extendible mechanism 2120B, which has a shorter length dimension that extendible mechanisms 2120A. The length dimension may be the minimum dimension in some embodiments or the maximum dimension of the member in other embodiments. It is further possible that the removable connection between the extendible mechanism 2120A and the first end 2130 and/or the second end 2140 may be such that a connection can be made or broken by a surgeon working at a surgical site with the first end 2130 or second end 2140 already attached to a part, such as a bone, of a patient's body. For example, such connection may comprise a close fit between a cavity in extendible mechanisms 2120A, 2120B in relation to end 2130, 2140. Such connection further may comprise a snap-in mechanism that may help retain ends 2130, 2140 in engagement with extendible mechanisms 2120 A, 2120B. Such connection could alternatively comprise a fractional-turn locking mechanism. Other connection designs are also possible.

[0094] Figure 12A is a sequence of plan views of the first member 2100 of Figure 11. The leftmost portion of Figure 12A illustrates extendable member 2120B in its retracted state removably coupled to ends 2130, 2140. The next portion of Figure 12A illustrates extendable member 2120B in a more extended state. The next portion of Figure 12A illustrates extendable member 2120 A, having replaced extendable member 2120B, in its retracted state and removably coupled to ends 2130, 2140. The next portion of Figure 12A illustrates extendable member 2120A in a more extended state. Figure 12B is the same sequence as Figure 12A, shown in cross-section.

Method of treatment

[0095] It can be understood that there are at least two types of change of configuration that can be experienced by the described apparatus after completion of surgery.

[0096] One such change in the configuration of the members may be associated with normal growth of the patient. In regard to normal growth, embodiments of the described devices allow normal growth to occur with no increase in scoliotic deviation and possibly with some reduction of scoliotic deviation. If the various components of the spine generally grow or lengthen as a result of normal growth, the first member 100/1100/2100/3100 allows an increase in the distance between the two places where it is attached to the spine, which essentially accommodates normal growth. Also, upon such growth, the second member 200, which may be attached to vertebrae at least at its two ends, may undergo angular change in its permitted angular direction, such that a general lengthening of the spine at least does not increase scoliotic deviation and may actually result in the spine becoming straighter.

[0097] Another type of change in the configuration of the members 100/1100/2100/3100, 200 may involve manipulation by a physician or other treatment provider. Such treatment may be performed without surgical intervention such as puncturing of the patient's skin. For example, the patient's spine may be stretched or manipulated in such a way as to extend the length of the first member 100/1100/2100/3100, or to change the angular position of the second member 200, or both, in any combination.

[0098] For example, manipulation so as to change the physical characteristics of either the first member 100/1100/2100/3100 or the second member 200 or both may be done periodically so as to move the spine into a closer-to-normal configuration. Such

manipulation may be followed by a period of time for tissues of the patient's body to adjust and accommodate the new configuration, and potentially followed by another manipulation. Again, it is possible to perform such manipulation without puncturing or penetrating through the skin of the patient or performing any surgical procedure.

[0099] It is also possible that the apparatus can be expanded or reconfigured using surgery, which may be minimally invasive surgery. For example, during such surgery, it might only be necessary to expose a portion of the first member 100/1100/2100/3100. For example, it might be possible to expand the apparatus by exposing only the inner cage 1162 of the first member 1100. It might not be necessary to expose or access the entire first member

100/1100/2100/3100 during such surgery. It is also possible that minimally invasive surgery could be used to reconfigure the second member 200, and it might be sufficient to expose only a portion of second member 200 during such surgery.

[00100] A method of use for one of the particular embodiments may be described here. In this embodiment, the first member 100 may be implanted in a patient, either on one side or on both sides of the spine, with ends 130, 140 attached to pedicle screws or to ribs in any combination. It is possible, for example, to implant the first member 100 on both sides of the spine if the scoliotic condition involves rotational malpositioning of the vertebrae more so than it involves lateral deformation of the spine. This is illustrated in Figure 13. It may be desirable to implant the first member 100 on both sides of the spine if the spine is fairly flexible and deformation correction can substantially occur at the time of implantation.

[00101] Yet another possibility is that the first member 100/1100/2100/3100 or the second member 200 or both may have a release latch that allows them to be released if, for some reason, they lengthen or rotate farther than desired, such as if a patient stretches or bends in such a way as to cause slippage of the member in the permitted direction but farther than is desired. For example, such a release latch could be actuated in response to an applied magnetic field. For example, if the member 100/1100/2100/3100 or 200 comprises a pawl, the pawl or a member associated with the pawl could be responsive to an applied magnetic field. With such an apparatus, if an appropriate magnet were brought sufficiently close to the apparatus, which could be done with the magnet outside the patient's body, the first member 100/1100/2100/3100 or the second member 200 could release and be able to contract or rotate in the direction that usually is not permitted.

[00102] It has been illustrated that in first member 100, first end piece 130 has a first end piece axis and second end piece 140 has a second end piece axis, and the two axes are essentially collinear with each other. It has also been illustrated that end pieces 130, 140 are spinal rods that are substantially straight. However, none of these features are essential. It is possible that end pieces 130, 140 could be non-aligned with each other, or offset with respect to each other, or could be curved, or any combination thereof.

[00103] One or more of the apparatus described herein may manufactured of materials that are suitable for implantation in the human body. Many such materials are known presently. In some embodiments one or more apparatus are made of titanium alloy, such as, for example, Ti-4Al-6Va.

[00104] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[00105] All definitions, as defined and used herein, should be understood to control over

dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

[00106] The indefinite articles "a" and "an," as used herein in the specification and in the

claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[00107] The phrase "and/or," as used herein in the specification and in the claims, should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with "and/or" should be construed in the same fashion, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the "and/or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and/or B", when used in conjunction with open-ended language such as "comprising" can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[00108] As used herein in the specification and in the claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when separating items in a list, "or" or "and/or" shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as "only one of or "exactly one of," or, when used in the claims, "consisting of," will refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein shall only be interpreted as indicating exclusive alternatives (i.e. "one or the other but not both") when preceded by terms of exclusivity, such as "either," "one of," "only one of," or "exactly one of." "Consisting essentially of," when used in the claims, shall have its ordinary meaning as used in the field of patent law. [00109] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently "at least one of A and/or B") can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another

embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[00110] It should also be understood that, unless clearly indicated to the contrary, in any

methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[00111] In the claims, as well as in the specification above, all transitional phrases such as

"comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of and "consisting essentially of shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

[00112] We claim:

Claims

Claims:

1. A spinal surgical apparatus, comprising:

a first member having an adjustable length, wherein said first member allows increase in said length and has at least one stop that at least selectively prevents decrease in said length of said first member; and

a second member allowing rotation in a first rotational direction but at least selectively preventing rotation in a second rotational direction opposed to said first rotational direction.

2. The apparatus of claim 1 , wherein said first member comprises a ratchet to control motion in a linear direction.

3. The apparatus of claim 1, wherein said second member comprises a ratchet to control motion in said first rotational direction.

4. The apparatus of claim 1 , wherein said first member has a first end and a second end.

5. The apparatus of claim 4, wherein at least one of said first end and said second end is hingedly attached.

6. The apparatus of claim 4, wherein at least one of said first end and said second end is hingedly attached and fixable at a desired hinged orientation.

7. The apparatus of claim 4, further comprising a pedicle screw configured to attach to a vertebra and receive at least one of said first end and said second end of said first member.

8. The apparatus of claim 7, wherein said pedicle screw includes a head and a shaft and wherein said head is rotatable with respect to said shaft after implantation of said shaft.

9. The apparatus of claim 8, wherein said head is a polyaxial head movably attached over a screw head attached to said shaft.

10. The apparatus of claim 8, wherein said head is a screw head.

11. The apparatus of claim 10, wherein said screw head includes a plurality of interior splines interfacing with a plurality of exterior splines of said shaft.

12. The apparatus of claim 1, wherein said first member has a first end and a second end, and at least one of said ends is removably attached to an adjustment mechanism of said first member.

13. The apparatus of claim 1, wherein said second member has a first end and a second end, and at least one of said ends is configured to be received by a pedicle screw.

14. The apparatus of claim 1, wherein said first member is lengthenable after surgical implantation in a patient by manipulating said patient non-surgically.

15. The apparatus of claim 14, wherein said second member is rotatable after surgical implantation in a patient by manipulating said patient non-surgically.

16. A method of treating an abnormally shaped spine in a patient, said spine having a concave portion and an opposed convex portion, said method comprising:

surgically implanting a first member into said patient adjacent said concave portion of said spine, said first member having an adjustable length, wherein said first member allows increase in said length and has at least one stop that at least selectively prevents decrease in said length of said first member;

surgically implanting a second member into said patient adjacent said convex portion of said spine, said second member allowing rotation in one rotational direction but at least selectively preventing rotation in an opposed direction.

17. The method of claim 16, wherein said first member has a first end and a second end, and at least one of said ends contacts a pedicle screw attached to a vertebra.

18. The method of claim 17, wherein said first end of said first member is connected to a first vertebra and said second end of said first member is connected to a second vertebra, and wherein said first vertebra and said second vertebra are separated by at least one vertebra not connected to said first member.

19. The method of claim 17, wherein said pedicle screw includes a head and a shaft and wherein said head is rotatable with respect to said shaft.

20. The method of claim 19, wherein said head is a screw head.

21. The method of claim 20, wherein said screw head includes a plurality of interior splines interfacing with a plurality of exterior splines of said shaft.

22. The method of claim 16, wherein said first member has a first end and a second end, and at least one of said ends grips a rib of said patient.

23. The method of claim 16, wherein said second member has a first end and a second end, and at least one of said ends contacts a pedicle screw attached to a vertebra.

24. The method of claim 16, wherein said second member has a first end and a second end, and at least one of said ends grips a rib of said patient.

25. The method of claim 16, further comprising manipulating said patient non-surgically to cause at least one of a lengthening of said first member and a rotation of said second member after said patient has substantially healed from said surgical implantation.

26. The method of claim 25, further comprising manipulating said patient non-surgically to cause a lengthening of said first member and a rotation of said second member after said patient has substantially healed from said surgical implantation.

27. The method of claim 16, wherein said manipulating step comprises positioning a patient's body.

28. The method of claim 16, further comprising manipulating at least one of said first member said second member non-surgically after said surgical implantation.

29. The method of claim 26, wherein said manipulating step comprises positioning a magnet proximal to at least one of said first member and said second member.

30. The method of claim 16, wherein said first member includes a rack and interfacing pawl.

31. A spinal surgical apparatus, comprising:

a first member comprising an extendible mechanism, a first end extending from said extendible mechanism, and a second end extending from said extendible mechanism, wherein said first end has a first end axis and said second end has a second end axis and said first end axis and said second end axis coincide with each other; and

a first pedicle screw which grasps said first end of said first member.

32. The apparatus of claim 31 , wherein said extendible mechanism allows an increase in a length of said first member but has stops which, at defined locations, prevent a decrease in said length of said first member.

33. The apparatus of claim 31, further comprising a second pedicle screw which grasps said second end of said first member.

34. The apparatus of claim 31 , wherein said first member provides a finite number of discrete positions at which it can resist compression, and said first member can advance from a shorter-length one of said discrete positions to a longer-length one of said discrete positions, but cannot advance from said longer-length one of said discrete positions to said shorter-length one of said discrete positions.

35. A method of treating an abnormally shaped spine in a patient, said spine having a concave portion and an opposed convex portion, said method comprising:

implanting, during a first surgery, a first member in said patient, wherein said first member comprises a first extendible mechanism, a first end detachably connected to said first extendible mechanism, and a second end detachably connected to said first extendible mechanism opposite said first end;

after said first surgery, allowing or causing said first member to lengthen;

during a subsequent surgery, removing said first extendible mechanism while leaving at least one of said first end and said second end in said patient's body; and

connecting a second extendible mechanism to said first end and said second end.

36. A spinal surgical apparatus, comprising:

a first extendible mechanism;

a first end detachably connectable to said first extendible mechanism;

a second end detachably connectable to said first extendible mechanism opposite said first end; and

a second extendible mechanism that is detachably connectable to said first end and said second end,

said second extendible mechanism having at least one dimension different from a corresponding dimension of said first extendible mechanism.

37. The apparatus of claim 36, wherein said first extendible mechanism allows increase in a length of said first extendible mechanism and has stops at defined locations that prevent decrease in said length of said first extendible mechanism

38. A spinal surgical apparatus, comprising:

a screw shaft having external threads;

a screw head integrally connected to said screw shaft;

a polyaxial head partly surrounding said screw head and movable with respect to said screw head, said polyaxial head having a recess for accepting a spinal rod;

wherein said screw head has at least a portion that is externally spherical and said polyaxial head has a portion that is internally spherical complementary to said screw head spherical portion; and

a rod fixedly receivable in said polyaxial head,

wherein, when said rod is held tightly in said polyaxial head, said screw head is movable with respect to said polyaxial head.

39. The spinal surgical apparatus of claim 38, wherein, when said rod is held tightly in said polyaxial head, said screw head is able to rotate around an axis coinciding with a longitudinal axis of said screw shaft.

40. The spinal surgical apparatus of claim 38, wherein, when said rod is held tightly in said polyaxial head, said screw head is able to rotate around three different mutually perpendicular axes of rotation.

41. The spinal surgical apparatus of claim 38, wherein, when said rod is held tightly in said polyaxial head, there is a gap between said spinal rod and said screw head.

42. A method of treating an abnormally shaped spine in a patient, said spine having a concave portion and an opposed convex portion, said method comprising:

implanting, during a first surgery, a first member in said patient, wherein said first member comprises a first extendible mechanism connected to a first end and a second end connected to said first extendible mechanism generally opposite said first end; connecting said first end to a first vertebra or rib;

connecting said second end to a second vertebra or rib; and

after said first surgery, allowing or causing said first member to lengthen by applying forces or motions to said patient non-surgically.

43. A spinal surgical apparatus, comprising:

a first member comprising an extendible mechanism and a first end extending from said extendible mechanism and a second end extending from said extendible mechanism, wherein at least one of said first end and said second end is a spinal rod; and

a pedicle screw which grasps said spinal rod.

44. A spinal surgical apparatus, comprising:

a first member comprising an extendible mechanism and a first end extending from said extendible mechanism and a second end extending from said extendible mechanism, wherein at least one of said first end and said second end is a spinal rod having a means for grasping a rib.

45. The spinal surgical apparatus of claim 44 wherein said means for grasping a rib comprises a hook.