WO2013009986A1

WO2013009986A1 - Flexible guide tube and methods of use thereof

Info

Publication number: WO2013009986A1
Application number: PCT/US2012/046474
Authority: WO
Inventors: Gary L. Graham; Erik Martz
Original assignee: Dgimed Ortho, Inc.
Priority date: 2011-07-14
Filing date: 2012-07-12
Publication date: 2013-01-17

Abstract

A flexible guide device is provided. The flexible guide device includes a housing having an internal channel, the internal channel including a first arcuate portion and a second linear portion; and a retractable guide tube assembly including an arcuate guide tube having a first portion and a second portion, the first portion slidingly positioned in the arcuate portion of the channel of the housing, the second portion being an actuating tube slidingly positioned in the linear portion of the channel of the housing, wherein the arcuate guide tube is controllably advanceable from the housing and retractable into the housing.

Description

FLEXIBLE GUIDE TUBE AND METHODS OF USE THEREOF

FIELD OF THE INVENTION

[0001] The present invention relates to a flexible guide tube that may be utilized in surgical procedures alone or in combination with a drill assembly.

BACKGROUND OF THE INVENTION

[0002] Surgical procedures often require the cutting or drilling of holes or channels into bone, teeth, or soft tissue, such as can be used for securing components made of metal or other materials to the bone of a patient. For example, these holes may be used to receive screws, sutures, or bone anchors, thereby allowing for implants or other devices to be secured to the bone, or to provide for reattachment of ligaments or tendons to a bone. Surgical procedures may also require the guidance of instruments and/or positioning of devices.

[0003] Among other uses, drilling devices may be used with intramedullary rods, commonly used in orthopedic surgery for breaks in the long bones of the extremities, such as the femur and tibia. These rods are used to align and stabilize fractures or breaks of bones and to maintain the bone fragments in their proper alignment relative to each other during the healing process. In order to maintain the intramedullary rod in the proper relationship relative to the bone fragments, it is often desirable to insert bone screws or other fasteners through the distal and proximal portions of the intramedullary rod and one or both fragments of the bone. In order to fix the rod to the bone, intramedullary rods are commonly provided with at least one aperture through each of their proximal and distal end portions for receiving screws or fasteners of various configurations. To insert such screws, the objective is to drill holes through the tissue and bone in proper alignment with the holes in the intramedullary rod, and to insert the screws through the holes to lock the intramedullary rod in place. Two primary reasons for failure in distal locking of the intramedullary rod to the bone using conventional drilling systems include using an incorrect entry point on the bone and having the wrong orientation of the drill. If either of these two factors exists, the drill bit may not go through the nail hole. An inaccurate entry point also compounds the problem if the rounded end of the drill bit is slightly out of position, thereby weakening the bone and sometimes making it difficult to find a strong point in the bone in which to place the correct drill hole. Inaccurate distal locking can lead to premature failure with breakage of the nail through the nail hole, breakage of the screw, or the breaking of the drill bit within the bone. In addition, if the distal end of the rod is not properly secured, bone misalignment and/or improper healing of the bone may occur.

[0004] A number of different surgical drilling devices are available for the purposes of drilling bone, teeth and/or soft tissue, many of which include a motor and a drill bit that can provide a hole of the desired depth and diameter. Examples of such devices are described in U.S. Pat. No. 5,695,513 to Johnson et al. and U.S. Pat. Publn. No. 2008/0114365 to Sasing et al, the disclosures of which are incorporated by reference herein for all purposes.

[0005] The Johnson et al. reference describes a helically wound cable made of a superelastic alloy. In this device, the cable is bent to a predetermined bend radius and rotated in a direction that tends to tighten the helically wound fibers of the cable. Drilling with this device is performed while continuously maintaining the cutting means at least partially within the hole being drilled and advancing the cable through its holder. However, the flexible cutting cable of Johnson et al. is received within a tubular support that is not capable of being slidingly advanced relative to its housing but rather is axially constrained within the housing. In addition, the element which guides the flexible cable into position is rigid so as to properly orient the cable as it emerges from the tubular support.

[0006] Sasing et al. improves upon the Johnson et al. device. Sasing et al. describe a surgical drilling device having a flexible cable drill and a retractable arcuate guide tube. The arcuate guide tube is capable of being slidingly advanced relative to the housing. However, the arcuate guide tube of the Sasing et al. device relies on a complicated structure that includes a spring that allows for a flexible connection with an actuating tube. If the spring is eliminated and the arcuate tube linked directly to the actuating tube it would permanently deform when slidingly retracted into the housing. Moreover, the arcuate guide tube has a limited diameter and thus the flexible cable can only drill holes which themselves are quite narrow. Simply increasing the diameter of the arcuate tube and spring is not feasible because the tube would no longer be able to guide the drill cable around the required angle and be centered in a hole in a standard intramedulary nail leading to failure in distal locking. Alternatively, the angle could be increased but the inner diameter of the nail would also need to increase in order to accommodate the larger outer diameter of the drill thus compromising the strength of the nail itself. As noted previously, inaccurate distal locking may lead to premature failure with breakage of the nail through the nail hole, breakage of the screw, or the breaking of the drill bit within the bone, bone misalignment and/or improper healing of the bone.

[0007] In addition to the foregoing, devices on the market today that facilitate distal locking of intramedullary nails rely on an additional control box or other power supply as the source of rotary power for the drilling device. This requires an additional capital expenditure by the surgeon, clinic and/or hospital that use drilling devices, adds to preparation and disassembly time for surgical staff and adds to the manufacturing cost of the drilling devices themselves.

[0008] Thus, there is a continued need for improving surgical drilling tools and methods for surgical procedures in which they are used that overcome the problems of conventional drilling devices outlined above.

BRIEF SUMMARY OF THE INVENTION

[0009] One aspect of the invention provides surgical drilling device including a housing, a retractable, flexible, pre-set guide tube assembly, and a flexible cable or wire drill. As used herein, "cable" is used synonymously with "wire." The cable or wire (such as Nitinol or other flexible material) drill may be solid or hollow. The retractable, flexible guide tube may comprise a full diameter or partial diameter assembly. Those skilled in the art will appreciate that if a partial diameter assembly is used the overall diameter of the guide tube assembly is reduced. The retractable, flexible guide tube assembly comprises an arcuate guide tube slidingly positioned in a first arcuate channel of the housing. The arcuate flexible guide tube is operably coupled to an actuating rod slidingly positioned in the first or a second channel of the housing wherein the actuating rod controllably advances and retracts the arcuate guide tube. The flexible cable drill is slidingly positioned in the arcuate flexible guide tube. The angle of the arcuate flexible guide tube is pre-set to an optimal angle depending on the particular surgical application. Having a retractable, flexible guide tube with a pre-set angle minimizes manufacturing costs and facilitates the navigation/advancement of the cable drill around various bend radius and angles to aid surgeons in orthopaedic, dental and other medical surgeons.

[0010] In a second aspect of the invention, a surgical drilling device is provided that includes a flexible, guide tube, a flexible cable drill received within the guide tube and operably coupled to a drill. The flexible guide tube may be connected to an actuating rod that is manually advanced by a surgeon. The actuating rod controllably advances and retracts the arcuate guide tube into position. In the case of an intramedullary rod, the arcuate guide tube is positioned adjacent the screw holes. The flexible guide tube may be formed from a shape memory material that causes the guide tube to expand to a "pre-determined" or "pre-set" shape when it is released from a sleeve or other type of housing. Suitable shape-memory materials may include copper-zinc-aluminium-nickel, copper-aluminum-nickel, and nickel-titanium (NiTi or Nitinol) alloys but those of skill in the art will appreciate that shape memory materials may also be created by alloying zinc, copper, gold and iron. The elasticity of the shape memory material causes the guide tube to assume a predetermined shape and angle when outside of the sleeve or housing and to contract to a collapsed state when restrained within the lumen of the sleeve or housing. The flexible cable or wire drill is slidingly received in the arcuate, flexible guide tube. In position and after the guide tube assumes its preset or pre-determined shape the flexible cable or wire is actuated to drill through adjacent bone to form a hole.

[0011] In a third aspect of the invention and in its simplest form, a flexible, guide tube or wire is provided. The flexible guide tube or wire may be used in a variety of surgical applications including using the flexible guide tube as the locking device; in dental applications such as oral surgery to access hard to reach molar areas; and in spinal surgery as a guide wire for pedical screw placement of rods. The flexible guide tube may formed from a shape memory material, such as Nitinol, that causes the guide tube to expand to a "pre-determined" or "pre-set" shape when it is released from a sleeve or other type of housing. The elasticity of the material causes the guide tube to assume a predetermined shape and angle when outside of the sleeve or housing and to contract to a collapsed state when restrained within the lumen of the sleeve or housing.

[0012] In a fourth aspect of the invention, the flexible guide tube may house a wire that can be deployed, optionally after drilling, to provide means to guide cannulated instruments or implants to a desired location.

[0013] The flexible guide tube and drill assembly may be adapted to fit standard intramedullary nails including femoral, tibial, humeral and the like. Further aspects of the invention are hereinafter described in the Detailed Description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

[0015] FIG. 1 is a perspective view of an exemplary surgical drilling device having a flexible arcuate retractable guide tube in accordance with the present invention.

[0016] FIG. 2 is a cross-sectional view of an exemplary surgical drilling device having a flexible arcuate guide tube in accordance with the present invention showing the flexible arcuate guide tube in an extended position and a cable drill extended from the arcuate guide tube.

[0017] FIG. 3 is a cross-section view of the surgical drilling device of FIG. 2 showing the flexible arcuate guide tube in a retracted position.

[0018] FIG. 4a is a cross-sectional view of another exemplary surgical drilling device having a flexible arcuate guide tube in which the guide tube exits the housing at an angle generally perpendicular to the exit channel.

[0019] FIG. 4b is a cross-sectional view of the surgical drilling device of FIG. 4a showing the flexible arcuate guide tube in a retracted position. [0020] FIG. 5 a is a cross-section view of a surgical drilling device in accordance with a further embodiment of the invention showing a sheath covering the flexible arcuate guide tube.

[0021] FIG. 5b is a cross-sectional view of the surgical drilling device of FIG. 5a depicting the sheath of FIG. 5 a in a retracted position and the pre-formed flexible arcuate guide tube passively exiting the sheath.

[0022] FIG. 6 illustrates a surgical drilling device in accordance with a further embodiment of the invention in which an internal diameter of an intramedullary rod serves as a sheath with the holes in the rod serving to release and deploy the flexible arcuate tube.

[0023] FIG. 7 illustrates a surgical drilling device in accordance with a further embodiment of the invention in which the drilling device includes two flexible arcuate guide tubes and an internal diameter of an intramedullary rod serves as a sheath with the holes in the rod serving to release and deploy the flexible arcuate tubes.

[0024] FIGS. 8a - 8e illustrates a flexible drill cable that is used as an implant with a cervical fracture.

[0025] FIGS. 9a - 9b illustrate an arcuate, flexible guide tube with flexible cable with drill bit head.

[0026] FIGS. 10a - 10b illustrate a flexible cable that is used as a locking screw with an intramedullary rod.

[0027] FIGS. 11a - l ib depicts the flexible guide tube assembly used in dental applications.

[0028] FIGS. 12a - 12b depicts the flexible guide tube assembly used in a discectomy or spinal applications.

[0029] FIGS. 13a - 13b illustrate the flexible guide tube assembly used in minimally invasive spine stabilization procedures. DETAILED DESCRIPTION

[0030] Referring now to the Figures, wherein the components are labeled with like numerals throughout the several Figures, and initially to FIGS. 1-3, an exemplary configuration of a surgical drilling device 10 comprising a retractable, flexible cable guide assembly is illustrated. The device 10, as shown, generally includes a housing 12, a retractable, flexible arcuate guide tube 14, a push rod 16 which is concentrically operably coupled with guide tube 14, a cable drill 18, and optionally a cable carrier 20. Housing 12, as shown, is generally cylindrical and comprises four channels that house the various components. Channel 22, through which the arcuate, flexible guide tube exits may be shaped generally like a section of a torus, for example, and is used for slidingly guiding the retractable, flexible arcuate guide tube 14. The torus shape functions to slidingly guide the retractable, flexible, arcuate guide tube 14 (which, as will be explained in detail, advantageously does not need to be similarly shaped). The flexible, arcuate guide tube 14 may be made from shape-memory metal, such as Nitinol, that is pre-set to the appropriate bend radius and angle for the specific surgical application desired. The shape of channel 22 may also be used to force the shape of guide tube 14 in addition to the pre-set shape attributable to the shape-memory material from which it is made. As an alternative to the "pre-determined" shape of the guide tube, the proximal end of the drill may include means for controllably advancing the flexible guide tube to deploy the flexible guide tube at the desired angle or at a multiplicity of angles that would be ideal for complex fractures. FIG. 2 depicts the flexible, arcuate guide tube in the extended position while FIG. 3 depicts the flexible, arcuate guide tube in the retracted position within channel 22. In the preferred embodiment, the flexible, arcuate guide tube is pre-set in a serpentine shape that allows it to easily exit channel 22. Due to its flexibility, when in the retracted position flexible, arcuate guide tube easily bends to accommodate the shape of channel 22.

[0031] The flexible arcuate guide tube assembly 14 of the present invention is directly operably coupled to actuating rod 24 by welding, glue, mechanical tabs, and/or crimping thereby advantageously eliminating the need for a spring as required by prior art devices. [0032] FIGS. 4a and 4b are cross-sectional views of another exemplary surgical drilling device having a flexible, arcuate guide tube. FIG. 4a depicts the flexible, arcuate guide tube in the extended position while FIG. 4b shows the flexible, arcuate guide tube in a retracted position. As seen, channel 22 has been modified in which the flexible, arcuate guide tube exits the channel 22 at a pre-set angle, which is generally perpendicular to a longitudinal axis of the housing.

[0033] FIGS. 5a and 5b depict another exemplary embodiment of a flexible, arcuate guide tube in accordance with the invention. A surgical drilling device, such as depicted in FIG. 1, may include an internal channel that accommodates a sheath 30 in accordance with a further embodiment of the invention. Alternatively, the exemplary surgical drilling device may eliminate the housing 12 depicted in FIG. 1 and solely include a sheath 30 having a lumen 31 in accordance with a further embodiment of the invention The flexible arcuate guide tube 14 is received within lumen 31 and is controllably retractable. The flexible arcuate guide tube 14 in accordance with this exemplary embodiment may again be formed from a shape memory material that causes the guide tube to assume to a "pre-determined" or "pre-set" shape when it is released from sheath 30. The elasticity of the material causes the guide tube to assume a predetermined shape and angle when outside of the sheath 30 and to contract to a collapsed state when restrained within the lumen 31 of the sheath 30. As sheath 30 retracts pre-formed flexible, arcuate guide tube passively exits the sheath allowing it to be deployed into its "pre-set" position. As those of ordinary skill in the art will appreciate the tip of flexible, arcuate guide tube may be pre-formed or pre-set to any desired angle depending on the use and/or application.

[0034] FIGS. 6 and 7 illustrate yet additional exemplary embodiments of the flexible, arcuate guide tube assembly. FIG. 6 illustrates a surgical drilling device in accordance with a further embodiment of the invention in which an internal diameter of an intramedullary rod 12 serves as a sheath which maintains the flexible, arcuate guide tube 14 in a loaded position. The screw holes 22 in the intramedullary rod 12 serve to release and deploy the tip of the flexible, arcuate guide tube 14 into the released or pre-set angle. It is contemplated that the guide tube 14 will be inserted toward the distal end of the internal channel of the intramedullary rod. To ensure that the guide tube does not deploy prematurely when being advance initially, the distal tip of the arcuate guide tube 14 can be oriented rotationally away from the locking screw 22 hole so that the distal tip will always be in contact with the inner wall of the intramedullary rod. As the flexible, arcuate guide tube is retracted proximally the tube is rotated to the correct orientation and deployed through the locking screw hole 22 where it assumes its pre-set angle.

[0035] In a further aspect of the invention FIG. 7 illustrates a surgical drilling device in which the drilling device includes two flexible arcuate guide tubes 14 and an internal diameter of an intramedullary rod 12 serves as a sheath with the locking screw holes 22 in the rod 12 serving to release and deploy the flexible arcuate tubes. Those of ordinary skill in the art will appreciate that any number of flexible guide tubes may be used to suit the specific medical application. Those of ordinary skill in the art will also appreciate that the flexible, arcuate guide tube coupled with the flexible cable of the invention can be used in surgical procedures that drill through bone, soft tissue or both.

[0036] In an exemplary method of using the flexible, arcuate guide tube in accordance with the invention, after drilling bone (by way of example) with the flexible cable, wire or drill bit the cable is removed from the drill and replaced with an exchange wire/stylet. In another aspect of the invention the cable and exchange wire are both contained within the arcuate guide tube. The exchange wire provides means to guide cannulated instruments or implants to a desired location. In an exemplary embodiment the wire cable of the invention is used to drill through bone and/or tissue. It is then retracted and the cable removed. The exchange wire is deployed from the flexible guide tube or alternatively the cable is removed from the drill and replaced with the exchange wire. The exchange wire may be advanced through the pre-drilled bone and through soft tissue. The wire can be used as a guide to drill back through the soft tissue using a cannulated drill bit sized to be received over the exchange wire and sized for locking screws to be inserted into, for example, the holes of an intramedullary rod. In other exemplary embodiments, cannulas, other instruments, and/or implants may be inserted over the wire or through tissue and/or bone. Those of ordinary skill in the art will appreciate that by varying the stiffness of the flexible cable drill it can be used in place of the exchange wire and the cannulated drill bit can drill over the flexible cable.

[0037] In one aspect of the invention, the need for a control box that supplies power or some degree of operational control to conventional drill assemblies is eliminated. A standard, hand-held power drill may be used to power the drilling by operably connecting the flexible drill cable to the drill. The feedback loop of conventional control boxes is replaced with tactile, visual and/or audible feedback and/or any combination of the foregoing. Thus, when the flexible cable drill drills though and exits the bone the user will feel a change in resistance and/or feel, see and/or hear the changes indicating that the drilling is complete. Linear advancement of the cable is provided by pushing and/or pulling the cable via the hand-held drill.

[0038] FIGS. 8a - 8e depict a flexible, arcuate guide tube and drill cable 810 that may be used as an implant to secure bone fragments, for example in a clavicle fracture 800. The arcuate, flexible guide tube 810 is advanced through the intramedullary space 812 of the clavicle and the flexible drill cable 814 drills through the intramedullary space until it exits the bone 816. The arcuate flexible guide tube is then removed, as shown in FIG. 8d, and the cable 814 remains. The two ends 818, 820 of the cable 814 may include a threaded coupling to receive a nut 822 which secures it in place. Alternatively, a crimp washer may be used at the first and second ends to secure the cable in place.

[0039] In yet another aspect of the invention and referring to FIG. 9, flexible drill cable 910 may include a drill bit 912 operably coupled to the distal end. The drill bit may be trocar shaped, fluted, cannulated, flat, flared and other shapes known to those skilled in the art. Pre-set, arcuate flexible guide tube 914 is advanced through housing 918. Those skilled in the art will realize that arcuate, flexible guide tube 914 can be used with a housing or without a housing as hereinbefore explained. Guide tube 910 is advanced though housing 918. As arcuate, flexible guide tube 914 reaches the screw hole 920 in intramedullary nail it assumes its preformed shape as it exits hold 920. In one aspect of the invention the drill cable is advanced and drill bit 912 exits screw hole 920 and drill through bone (not shown) and/or tissue (not shown). The drill bit is retracted and the surgeon using techniques known to those skilled in the art or described herein may fasten screws through the screw holes to secure the intramedullary rod in place.

[0040] Alternatively, as seen in FIG. 10, the flexible drill cable 1012 can be used alone or in combination with a pre-formed, flexible, arcuate guide tube. As shown, flexible drill cable 1012 is advanced through housing 1014, screw opening 1015 in intramedullary nail 1016 and through bone 1018. Drill cable 1012 includes washer 1020 coupled to a mid-point thereof. Drill cable 1012 is advanced through the bone until washer 1020, which has an outer diameter that is greater than the diameter of screw opening 1015, lays adjacent screw opening 1015. The distal end of drill cable 1012 is capped with like washer 1021. The portion of flexible drill cable 1012 that lies proximal to washer 1020 is then cut and intramedullary rod is secured in position.

[0041] FIG. l la-l lb depict the present invention for use in dental applications such as root canal, cavity repair, tooth reconstruction and for use in hard to reach areas such as molars thereby preserving as much natural tooth structure as possible. As depicted in FIG. 1 1a, the tooth 1100 generally includes an enamel portion (the outer coating of the tooth) 1112, dentin (the inner layer of the tooth) 1114, a pulp chamber 11 16 and a root canal 1118. Cavities 1120 occur as a result of tooth decay. Tooth decay is the destruction of tooth structure. Tooth decay can affect both the enamel 1 112 and the dentin (the inner layer of the tooth) 1114. Tooth decay occurs when foods containing carbohydrates (sugars and starches) such as breads, cereals, milk, soda, fruits, cakes, or candy are left on the teeth. Bacteria that live in the mouth digest these foods, turning them into acids. The bacteria, acid, food debris, and saliva combine to form plaque, which clings to the teeth. The acids in plaque dissolve the enamel surface of the teeth, creating holes in the teeth called cavities, or caries.

[0042] If decay is not extensive, the decayed portion 1120 of the tooth is removed by drilling and replaced with a filling made of silver alloy, gold, porcelain, or a composite resin. A dentist may insert the arcuate flexible tube assembly 1122 near the surface of the tooth and the drill cable or wire 1124 exits at a preformed angle (as hereinbefore explained) and advanced into the tooth structure at the precise angle as the cavity is located. FIG. 1 1a also depicts the arcuate flexible guide tube and drill assembly used in a hard to reach molar area to repair a cavity.

[0043] FIG. l ib depicts the flexible arcuate guide tube assembly used in a root canal 11 18. A root canal is the space within the root of a tooth. It is part of a naturally occurring space within a tooth that consists of the pulp chamber 1 1 16 (within the coronal part of the tooth), the main canal(s) 1118, and more intricate anatomical branches that may connect the root canals to each other or to the surface of the root (not shown). The smaller branches, referred to as accessory canals, are most frequently found near the root end (apex) but may be encountered anywhere along the root length. There may be one or two main canals within each root, which is filled with a highly vascularized, loose connective tissue, the dental pulp. The dental pulp is the tissue of which the dentin portion of the tooth is composed. The dental pulp helps complete formation of the secondary teeth (adult teeth) one to two years after eruption into the mouth. The dental pulp also nourishes and hydrates the tooth structure which makes the tooth more resilient, less brittle and less prone to fracture from chewing hard foods. Additionally, the dental pulp provides a hot and cold sensory function. In a root canal, the pulp is cleaned out, the space disinfected and then filled. As depicted in FIG. l ib the arcuate flexible guide tube 1122 is introduced in to the canal. The drill cable or wire exits the arcuate flexible guide tube at a predetermined angle and rotatably advanced to clean out the pulp. The pulp is suctioned out, the resulting space in the root canal 1118 is disinfected and then filled.

[0044]. FIG. 12 depicts the flexible guide tube assembly used in spinal applications. In a first embodiment, the flexible guide tube assembly may be used in a discectomy. A discectomy (also called "open discectomy") is the surgical removal of herniated intervertebral disc material that presses on a nerve root or the spinal cord. Normally, the disc 1210, with it gelatinous nucleus pulposus 1212, functions as a cushion. The nucleus pulposus 1212 is the central gelatinous part of the intervertebral disc 1210 which sometimes hardens as it ages. When it hardens it may impinge on spinal or radiating nerves causing pain. A discectomy procedure involves removing the nucleus pulposus 1212. In conjunction with the traditional discectomy, a laminectomy may sometimes be done in conjunction with the discectomy to permit access to the intervertebral disc. In this procedure, a small piece of bone (the lamina) is removed from the affected vertebra, allowing the surgeon to better see and access the area of disc herniation. Referring to FIG. 12a 12-b, disc cutting means such as hooks, curettes, wire brushes, laser, ultrasound, water jets and the like, are deployed through the flexible guide tube and controllably released at the desired angle (by means previously discussed) to reach the targeted areas of the disc. The disc cutting means may be used in conjunction with irrigation and/or suction means known to those of skill in the art. After the material is removed from the disc the disc cutting means are retracted into the flexible guide tube and the flexible guide tube removed from the intervertebral disc.

[0045] Referring now to FIGS. 13a - 13b the flexible guide tube is depicted being used in a minimally invasive spinal fusion procedure. Each spinal segment includes two adjacent vertebrae, their posterior bony elements, an intervertebral disc between the two vertebrae, ligaments, and two facet joint capsules. Each vertebra has a posterior vertebral element which, when removed, leaves first and second pedicles on each of the vertebra. Stabilizing two or more vertebrae together is done in an attempt to improve spinal stability and prevent the occurrence of "slipped disks" and other related spinal problems, and to treat disability due to pain and/or pinched nerves. Spinal fusion is a process using bone graft to cause two opposing vertebrae to grow, or weld, together. To ensure position and rigid alignment while fusion takes place, surgeons apply spinal instruments, or implants, such as screws and rods to the spine in particular to the pedicles. These implants are joined together to maintain spinal stability and are rarely removed. Spinal fusion and implants are used to restore stability to the spine, correct deformity and bridge spaces created by the removal of damaged spinal elements such as discs.

[0046] Referring to FIGS. 13a and 13b, a first vertebra 1310 and a second vertebrae 1311 (also known as vertebral bodies) separated by disc 1312 are shown. By first and second vertebrae we mean any vertebrae that are adjacent to each other. Each vertebra has a posterior element (not shown). When the posterior element (not shown) is removed from a vertebra the pedicles 1314a - 1314d are exposed. Pedicle screws 1316 are used as anchoring devices in spinal stabilization procedures and are placed into pedicles 1314a - 1314d by procedures known to those skilled in the art. After placement of the pedicle screw 1316 the drill assembly 1317 of the present invention is advanced to the site of the pedicle screw 1316. The flexible arcuate guide tube 1319 is advanced from the drill and the wire or cable 1320 is advanced through the guide tube at the appropriate predetermined angle (or at multiple angles as hereinbefore explained) drilling a hole through the head/end cap 1318a of the pedicle screw 1316. The wire 1320 is advanced further and drills into the second end cap 1318b of the adjacent pedicle screw and exits through soft tissue 1322 and skin 1324. After the cable/wire has exited the skin 1324 a cannulated rod 1325 is introduced over the wire 1320, back through the soft tissue 1322. Wire 1320 is retracted from second end cap 1318b and through first end cap 1318a of the adjacent pedical screws into the flexible guide tube 1319. Flexible guide tube 1319 is retracted into drill housing 1317. Cannulated rod 1325 is advanced from the soft tissue 1322 through end cap 1318b and end cap 1318a. The rod is then locked into place by a threaded coupling, nut, crimp washer or other means known to those skilled in the art, which secures the rod in place and stabilizes the vertebrae.

[0047] Although the description provided above is directed primarily to procedures that involve drilling into bone, the same concepts are equally intended to be applicable to other tissues and body structures, such as cartilage, skin, muscle, fat, and the like. In addition, combinations of any of these various structures with each other and/or in combination with bone structures are intended to be encompassed by the descriptions provided herein.

[0048] The present invention has now been described with reference to several embodiments thereof. The entire disclosure of any patent or patent application identified herein is hereby incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Thus, the scope of the present invention should not be limited to the structures described herein, but only by the structures described by the language of the claims and the equivalents of those structures.

Claims

A flexible guide device comprising: a housing having an internal channel, the internal channel including a first arcuate portion and a second linear portion; a retractable guide tube assembly comprising an arcuate guide tube having a first portion and a second portion, said first portion slidingly positioned in the arcuate portion of the channel of the housing, the second portion comprising an actuating tube slidingly positioned in the linear portion of the channel of the housing, wherein the arcuate guide tube is controllably advanceable from the housing and retractable into the housing.

The flexible guide device of claim 1 further comprising a flexible cable drill having a cutting end and having a first portion slidingly positioned in the arcuate guide tube and a second portion slidingly positioned in the actuating tube.

The flexible guide device of claim 1 wherein an angle of the arcuate flexible guide tube is set to a predetermined bend radius.

The flexible guide device of claim 1 wherein the arcuate flexible guide tube comprises a full diameter or a partial diameter guide tube.

The flexible guide device of claim 1 wherein the arcuate flexible guide tube comprises a shape-memory material.

The flexible guide device of claim 4 wherein the arcuate flexible guide tube has a predetermined shape and angel when located outside the housing and is configured to contract to a collapsed state when restrained within the housing.

The flexible guide device of claim 1 further comprising a wire positioned within said arcuate flexible guide tube for guiding cannulated instruments or implants.

8. The flexible guide device of claim 1 wherein the first arcuate portion and the second linear portion of the internal channel are integrally formed.

9. The flexible guide device of claim 1 wherein the first arcuate portion and the second linear portion of the internal channel are operably coupled to the fist arcuate portion by welding, glue, mechanical tabs or crimping.

10. The flexible guide device of claim 1 wherein the first arcuate portion of the internal channel is generally perpendicular to a longitudinal axis of the housing.

1 1. A flexible guide device comprising: a housing having an internal channel; a retractable sheath slidingly positioned within said internal

channel a flexible guide tube assembly positioned with said sheath, said flexible guide tube assembly having a first portion for exiting said sheath and a second portion, said first portion including a predetermined bend radius wherein when said sheath is slidingly retracted in said internal channel the first portion of said flexible guide tube assumes the

predetermined bend radius.

12. A flexible guide device comprising: an intramedullary rod having an internal channel and a plurality of screws holes; a flexible guide tube positioned with said internal channel, said flexible guide tube assembly including a distal tip having a first configuration and a predetermined second

configuration wherein when said flexible guide tube is . adjacent one of said plurality of screw holes the distal tip is configured to expand into said second configuration.

13. The flexible guide device of claim 12 wherein said predetermined second configuration comprises a predetermined bend radius.

14. The flexible guide device of claim 2 wherein said flexible cable is operably connected to a hand-held power drill.

15. The flexible guide device of claim 14 further including tactile, visual or audible feedback.

16. The flexible guide device of claim 2 wherein said cutting end is trocar shaped, fluted, cannulated, flat, or flared.