Abstract:
The intervertebral disc is avascular. With aging, nutrients and oxygen transporting through the endplates diminish. The disc degenerates, and pain ensues. Delivery devices are used to deliver a conduit through a pedicle or vertebral body into the intervertebral disc to re-establish the exchange of nutrients and waste between the disc and bodily circulation to slow, stop or reverse disc degeneration and relieve pain.

Description:
CROSS-REFERENCES TO OTHER APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 10/840,816 filed on May 7, 2004. This application also claims priority of U.S. Provisional Application 60/582,228 filed on Jun. 22, 2004; 60/587,837 filed on Jul. 14, 2004; and 60/660,120 filed on Mar. 8, 2005.  
         [0002]     This application is also a continuation-in-part of U.S. patent application Ser. No. 10/470,181, filed on Jul. 21, 2003, which is a National Stage Application of PCT/US02/04301-filed Feb. 13, 2002, which claimed priority of U.S. Provisional Application 60/268,666 filed on Feb. 13, 2001; 60/297,556 filed on Jun. 11, 2001; 60/310,131 filed on Aug. 3, 2001; 60/325,111 filed on Sep. 26, 2001; and 60/330,260 filed on Oct. 17, 2001. This application also claims priority of U.S. Provisional Application 60/468,770 filed on May 7, 2003; 60/480,057 filed on Jun. 20, 2003; 60/503,553 filed on Sep. 16, 2003; and 60/529,065 filed on Dec. 12, 2003. 
     
    
     FIELD OF INVENTION  
       [0003]     This invention relates to delivery devices and methods to implant a disc shunt to re-establish the transport of nutrients and waste between the disc and vertebral body to halt, decrease or reverse disc degeneration. As a result, back pain is reduced or alleviated.  
       BACKGROUND  
       [0004]     The intervertebral disc absorbs most of the compressive load of the spine with the facet joints of the vertebral bodies sharing approximately 16%. The disc consists of three distinct parts: the nucleus pulposus, the annular layers and the cartilaginous endplates. The disc maintains its structural properties largely through its ability to attract and retain water. A normal disc contains 80% water in the nucleus pulposus. The nucleus pulposus within a normal disc is rich in water retaining sulfated glycosaminoglycans, which create the swelling pressure necessary to provide tensile stress within the collagen fibers of the annulus. The swelling pressure produced by high water content is crucial to support the annular layers and sustain compressive loads.  
         [0005]     In adults, the intervertebral disc is avascular. Survival of the disc cells depends on nutrients supplied from external blood vessels. Penetration of nutrients and oxygen into the disc can be diffusion or pressure driven. Diffusion of nutrients flows from high to low concentration. Nutrients also flow from high to low pressure area. The sources of nutrients and oxygen are from (1) peripheral blood vessels adjacent to the outer annulus, and (2) vertebral body through the endplate into the disc. Diffusion of nutrients from peripheral blood vessels can only reach up to 1 cm into the annular layers of the disc. However, an adult disc can be as large as 5 cm in diameter, leaving the inner disc inadequately supplied with nutrients from the peripheral blood vessels. Hence permeation of nutrients and oxygen through cranial and caudal cartilaginous endplates is crucial for maintaining the health of the nucleus pulposus and inner annular layers of the disc.  
         [0006]     Calcium pyrophosphate and hydroxyapatite are commonly found in the endplate and nucleus pulposus. Beginning as young as 18 years of age, calcified layers begin to accumulate in the cartilaginous endplate. The blood vessels and capillaries at the bone-cartilage interface are gradually occluded by the build-up of the calcified layers. When the endplate is obliterated by the calcified layers, nutrient transport through the endplate is greatly hindered. Sulfate is one of the restricted nutrients for biosynthesizing the water-retaining sulfated glycosaminoglycans. As a result, the concentration of sulfated glycosaminoglycans decreases, leading to lower water content and swelling pressure within the nucleus pulposus. During normal daily compressive loading on the spine, the reduced pressure within the nucleus pulposus can no longer distribute the forces evenly along the circumference of the inner annulus to keep the lamellae bulging outward. As a result, the inner lamellae sag inward while the outer annulus continues to bulge outward, causing delamination of the annular layers.  
         [0007]     The shear stresses causing annular delamination and bulging are highest at the posteriolateral portions adjacent to the neuroforamen. The nerve is confined within the neuroforamen between the disc and the facet joint. Hence, the nerve at the neuroforamen is vulnerable to impingement by the bulging disc or bone spurs.  
         [0008]     The nucleus pulposus is thought to function as “the air in a tire” to pressurize the disc. With inadequate swelling pressure, the degenerated disc exhibits unstable movements, similar to that of a flat tire. Approximately 20-30% of low-back-pain patients have been diagnosed as having spinal segmental instability. The pain may originate from stress and increased load on the facet joints and/or surrounding ligaments.  
         [0009]     In addition, the calcified endplate also hinders permeation of oxygen into the disc. Oxygen concentration in the central part of the nucleus is extremely low. Under anaerobic conditions, metabolic production of lactic acid increases, leading to acidic conditions within the disc. Lactic acid diffuses through micro-tears in the annulus and irritates the richly innervated posterior longitudinal ligament, facet joint and/or nerve root. Studies indicate that lumbar pain correlates well with low pH. The mean pH of symptomatic discs was significantly lower than the mean pH of normal discs. Currently, no intervention other than discectomy stops or reduces the production of lactic acid.  
         [0010]     Conduits for re-establishing the exchange of nutrients and waste between the degenerative disc and bodily circulation is described in PCT/US2004/14368 (WO 2004/101015), and U.S. application Ser. No. 10/840,816 by J. Yeung and T. Yeung, both applications filed on May 7, 2004. The U.S. Ser. No. 10/840,816 is a continuation-in-part application to U.S. Ser. No. 10/470,181 by J. Yeung and T. Yeung on Jul. 21, 2003 from PCT/US2002/04301 on Feb. 13, 2002 with priorities dated on Feb. 13, 2001, Jun. 11, 2001, Aug. 3, 2001, Sep. 26, 2001 and Oct. 17, 2001. By re-supplying the cells within the disc with nutrients, biosynthesis of sulfated glycosaminoglycans may increase to retain additional water and sustain compressive loading. Hence, segmental instability and excessive loading on facet joints are minimized. With the presence of additional oxygen, production of lactic acid may decrease to minimize acidic irritation. Both retaining additional water and minimizing lactic acid build-up within the disc may halt or reverse disc degeneration and alleviate back pain.  
         [0011]     A method providing nutrients to an intervertebral disc through a porous stent or a cannulated element is proposed in U.S. Pat. No. 6,685,695 by Bret Ferree on Feb. 3, 2004. U.S. Pat. No. 6,685,695 and related applications have not mentioned specific method, delivery device or specification of the porous stent or cannulated element. Due to surrounding nerves, shielding of spinal structure and adjacent blood vessels, the method and delivery device for implanting the stent or cannulated element at the endplate are far from obvious. In addition, endplate punctures to provide passages for nutrients entering into the disc have been proposed in PCT/US2002/04301 by J. Yeung and T. Yeung on Feb. 13, 2002 with provisional application filed on Feb. 13, 2001. Furthermore, nucleus content of the disc is immunologic. Large pores in a stent or cannulated element provide sizable entries for IgG, IgM, interleukins-6, prostaglandin E 2 , giant cells or other immune responsive component to enter into the disc, which can cause significant immunologic reactions. Through large pores, the nucleus content can also be extruded from the disc and cause immunological response, as seen around herniated discs.  
         [0012]     Discs L4-5 and L5-S1 are shielded by the iliac, not accessible by straight needle from outside to deliver the conduit into the disc. However, through the pedicle of the vertebral body, the elastically curved needle proposed in PCT/US2004/14368 (WO 2004/11015) can puncture through the calcified endplate to deliver the conduit for nutrient and lactate exchange.  
       SUMMARY OF INVENTION  
       [0013]     This invention includes new methods and devices for implanting a conduit and a plug to seal the gap between the conduit and the endplate. Since discs L4-5 and L5-S1 are shielded by the iliac, a method using an elastically curved needle through the pedicle to puncture and deliver the conduit at the endplate is proposed. In addition, another proposed method is to drill through the sacrum into lumbar vertebral bodies to implant a conduit through multiple discs.  
         [0014]     In the supine position, the pressure within the shunted disc is low. Nutrients and oxygen from the vertebral body are transported through the conduit into the deprived cells within the disc. Biosynthesis of sulfated glycosaminoglycans may substantially increase to retain additional water to sustain the compressive load, ease strain on the facet joint and minimize segmental instability. In addition, anaerobic production of lactic acid may decrease with the presence of oxygen. During daily activities, pressure within the shunted disc is high. Lactic acid, carbon dioxide and metabolic waste within the disc are expelled through the conduit into bodily circulation. As a result, metabolic conditions within the shunted disc is normalized. The disc degenerative process is halted or reversed to reduce or alleviate back pain.  
       REFERENCE NUMBER  
       [0000]    
       
           100  Intervertebral disc  
           101  Needle  
           105  Endplate  
           106  Cartilage  
           108  Calcified layer or blockade  
           109  Plunger  
           111  Rectum  
           112  Blood vessels  
           117  Endoscope  
           118  Nerve  
           119  Colon  
           120  Inferior fascia pelvic diaphragm  
           121  Neuroforamen  
           123  Spinal cord  
           126  Conduit or shunt  
           128  Nucleus pulposus  
           129  Facet joint  
           136  External anal sphincter muscle  
           137  Coccyx  
           138  Anococcygeal body  
           139  Gluteus maximus muscle  
           140  Sacrum  
           141  Blunt obturator  
           142  Superior articular process  
           143  Inferior articular process  
           144  Blunt rod  
           145  Colon positioner  
           146  Suction cup  
           147  Positioner body  
           148  Positioner handle  
           149  Vacuum line  
           150  Drill  
           151  Genital  
           152  Puncture site  
           159  Vertebral body  
           163  Coating  
           191  Strain relieving element  
           194  Nerve root  
           195  Posterior longitudinal ligament  
           220  Rigid needle  
           230  Sheath  
           269  Lumen of needle  
           271  Plug sleeve  
           278  Pedicle  
           279  Drill stop  
           290  Cutting groove  
           292  Endplate plug  
           293  Plug slit  
           294  Plug thread  
           295  Plug lumen  
           296  Plug nut  
           297  Drill base  
           298  Drill grip  
           299  Drill fastener  
           300  Drill shaft  
           301  Gear A  
           302  Second gear  
           303  Drive hole  
           304  Fastening nut  
           305  Crank handle  
           306  Drill housing  
           307  Bolt  
           308  Nut  
           309  Needle slit  
           310  Bevel  
           311  Slide  
           312  Slide lumen  
           313  Drill sleeve  
           314  Lumen of drill or core  
           315  Cutting element 
       
     
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0085]      FIG. 1  shows a pedicle  278  punctured by a rigid needle  220  carrying an elastically curved needle  101  containing a conduit  126  (not shown) and a plunger  109 .  
         [0086]      FIG. 2  depicts the superior view of the vertebral body  159  with the rigid needle  220  puncturing through the pedicle  278 .  
         [0087]      FIG. 3  shows insertion of the rigid needle  220 , elastically curved needle  101 , conduit  126  and plunger  109  through the pedicle  278  of the vertebral body  159 .  
         [0088]      FIG. 4  shows deployment of the elastically curved needle  101  from the rigid needle  220 , puncturing through the calcified endplate  105  into the intervertebral disc  100 .  
         [0089]      FIG. 5  shows the superior view of an endplate  105  punctured by the elastically curved needle  101  carrying the conduit  126 .  
         [0090]      FIG. 6  shows retrieval of the elastically curved needle  101  into the rigid needle  220 . The plunger  109  has been held stationary to deploy the conduit or shunt  126  bridging the vertebral body  159  to the disc  100 .  
         [0091]      FIG. 7  shows the top view of the endplate shunt or conduit  126  after retrieval of the elastically curved needle  101  into the rigid needle  220 .  
         [0092]      FIG. 8  depicts an anterior approach for implanting the endplate shunt  126  by retracting the blood vessels  112  and drilling-through the vertebral body  159  toward the middle of the endplate  105 .  
         [0093]      FIG. 9  shows the side view of the drilling of the vertebral body  159  toward the center of the endplate  105 . The drill bit  150  contains a drill stop  279  to prevent excessive drilled depth.  
         [0094]      FIG. 10  shows a needle  101  carrying a conduit  126  and plunger  109  puncturing through the endplate  105  into the disc  100  to deliver the endplate shunt  126 .  
         [0095]      FIG. 11  shows the endplate shunt  126  bridged between interior of the vertebral body  159  and the disc  100 .  
         [0096]      FIG. 12  shows a flexible drill bit  150  with cutting grooves  290 , strain-relieving elements  191 , shaft  300 , base  297 , grip  298  and fastener  299 .  
         [0097]      FIG. 13  shows another flexible drill bit  150  with a thin flexible shaft  300 .  
         [0098]      FIG. 14  shows another flexible drill bit  150  with a flexible coil as the shaft  300 .  
         [0099]      FIG. 15  depicts a gear  301  with a drive hole  303  sized and configured to fit the grip  298  of the flexible drill bit  150 .  
         [0100]      FIG. 16  depicts a flexible drill bit  150  attached to the gear  301  driven by a second gear  302  connected to a crank handle  305 .  
         [0101]      FIG. 17  shows slits  309  at the distal end of the elastically curved needle  101 .  
         [0102]      FIG. 18  shows drilling of the calcified endplate  105  by the flexible drill bit  150  positioned, guided or directed by the elastically curved needle  101 .  
         [0103]      FIG. 19  shows entry of the collapsible slit needle  101  into the drilled hole of the endplate  105 .  
         [0104]      FIG. 20  depicts a beveled  310  tip of the slit needle  101  to facilitate endplate  105  entry.  
         [0105]      FIG. 21  shows multiple slits  309  at the distal end of the elastically curved needle  101 .  
         [0106]      FIG. 22  shows a conduit  126  and a plunger  109  on a flexible slide  311  with a sharpened tip.  
         [0107]      FIG. 23  depicts insertion of the flexible slide  311  carrying the conduit  126  into the pre-drilled hole.  
         [0108]      FIG. 24  depicts deployment of endplate conduit  126  by withdrawing the slide  311  and holding the plunger  109  stationary.  
         [0109]      FIG. 25  shows a thin drill sleeve  313  over the drill bit  150 .  
         [0110]      FIG. 26  shows a conduit  126  abutting a plunger  109  exiting from a lumen  312  of a tubular portion of the slide  311 .  
         [0111]      FIG. 27  depicts advancement of the drill sleeve  313  over the drill  150  after endplate  105  drilling, as shown in  FIG. 18 .  
         [0112]      FIG. 28  shows replacement of the drill  150  with the conduit  126  and slide  311 , as shown in  FIG. 26 , being inserted into the drill sleeve  313 .  
         [0113]      FIG. 29  shows withdrawal of the drill sleeve  313  into the curved needle  101 , exposing the conduit  126  on the slide  311 . The conduit  126  is then deployed by withdrawing the slide  311 , while holding the plunger  109  stationary.  
         [0114]      FIG. 30  shows a drill  150  with cutting elements  315  and a lumen  314  containing the conduit  126  and slide  311 .  
         [0115]      FIG. 31  shows the slide  311  and plunger  109  extending proximally from the fastener  299  and the grip  298  of the drill  150 , shown in  FIG. 30 .  
         [0116]      FIG. 32  shows drilling of the endplate  105  with the cutting elements  315 , then the conduit  126  and slide  311  are inserted into the lumen  314  of the drill  150 .  
         [0117]      FIG. 33  shows horizontally oriented strain-relieving elements  191  of the drill  150 .  
         [0118]      FIG. 34  shows longitudinally oriented strain-relieving elements  191 .  
         [0119]      FIG. 35  shows insertion of a trocar  103  to clear debris cored by the cutting elements  315 .  
         [0120]      FIG. 36  depicts a swellable coating  163  for sealing the gap between the conduit  126  and endplate  105 .  
         [0121]      FIG. 37  depicts a cone-shaped endplate plug  292  with a lumen  295 .  
         [0122]      FIG. 38  shows the plug  292  capable of sliding over the needle  101  punctured through the endplate  105 .  
         [0123]      FIG. 39  shows a plug sleeve  271  pushing the plug  292  into the punctured hole of the calcified endplate  105 .  
         [0124]      FIG. 40  shows withdrawal of the needle  101  while the sleeve  271  further advancing the plug  292  to seal between the conduit  126  and endplate  105 , while the plunger  109  is held stationary to deploy the conduit  126 .  
         [0125]      FIG. 41  depicts hydration and swelling of the plug  292  sealing the gap between the conduit  126  and the calcified endplate  105 .  
         [0126]      FIG. 42  shows a cone-shaped endplate plug  292  with a closable slit  293 .  
         [0127]      FIG. 43  shows the endplate plug  292  being slid over the needle  101  by the plug sleeve  271 .  
         [0128]      FIG. 44  shows closing of the slit  293  after being slid off the needle  101  to seal the gap between the plug  292  and the calcified endplate  105 .  
         [0129]      FIG. 45  shows an endplate plug  292  with self-tapping thread  294 .  
         [0130]      FIG. 46  shows a nut  296  portion for rotating and advancing the plug  292  into the endplate  105 .  
         [0131]      FIG. 47  shows that a flexible sleeve  271  fits over the nut  296  for advancing the plug  292  over the needle  101 .  
         [0132]      FIG. 48  shows a cross-section of the plug  292 , nut  296 , plug lumen  295 , slit  293 , needle  101  and conduit  126 .  
         [0133]      FIG. 49  shows the cross-section after withdrawal of the needle  101  and closure of the slit  293  to seal the conduit  126  within the lumen  295  of the plug  292  in the endplate  105 .  
         [0134]      FIG. 50  shows shape distortion of the nut  296  after slit  293  closure, creating free spinning of the sleeve  271  to prevent excessive plug  292  tightening into the endplate  105 .  
         [0135]      FIG. 51  shows puncture sites  152 , marked by two “X” marks, for implanting an endplate shunt  126  through multiple discs  100 .  
         [0136]      FIG. 52  depicts the compliant nature of the colon  119 . A rod  144  through the rectum  111  cannot reposition the colon  119  to allow insertion of the obturators  141 .  
         [0137]      FIG. 53  shows a colon positioner  145  equipped with a vacuum line  149  and a suction cup  146  for holding or lifting the inner lining of the colon  119 .  
         [0138]      FIG. 54  shows vacuum suction of the positioner  145  lifting the colon  119  to provide entries to the obturators  141  within the sheaths  230 .  
         [0139]      FIG. 55  shows replacements of obturators  141  with a drill  150  and an endoscope  117 , drilling superiorly into vertebral bodies S1 to as high as L3.  
         [0140]      FIG. 56  shows replacement of the drill with a needle  101  containing a long conduit  126  abutted against a plunger  109 .  
         [0141]      FIG. 57  shows deployment of the conduit  126  by withdrawing the needle  101  while holding the plunger  109  stationary. The conduit  126  reestablishes exchange of nutrients and waste for multiple discs  100 . 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0142]     Pedicle  278  puncturing with a trocar can be guided by a fluoroscope, ultrasound or MRI. The trocar can also be coated with radiopaque, echogenic or magnetic coating to intensify the image. A tubular dilator is inserted over the trocar. The trocar is then replaced with a drill, which drills into the pedicle  278  toward the center of the vertebral body  159 .  
         [0143]     The drill is replaced with a conduit  126  delivery device. The delivery device contains a conduit  126  abutted against a plunger  109  within an elastically curved needle  101 . The elastically curved needle  101  is resiliently straightened within a rigid needle  220 .  FIG. 1  shows insertion of the conduit  126  delivery device through the dilator, not shown, into the pedicle  278 . The pedicle  278  puncturing circumvents the iliac blockage and prevents potential injury to the nerve  194 , as shown in  FIG. 2 .  FIG. 3  shows a side view of a pedicle  278  puncture into the vertebral body  159  with the rigid needle  220  containing the elastically curved needle  101 , conduit  126  and plunger  109 .  FIG. 4  shows deployment of the elastically curved needle  101  from the rigid needle  220 . The elastically curved needle  101  resumes the curvature when deployed from the rigid needle  220  and punctures through the calcified endplate  105  into the intervertebral disc  100 . The center of the calcified endplate  105  is usually the thinnest portion; therefore it is a good location for puncturing.  FIG. 5  shows the superior view of endplate  105  puncture by the elastically curved needle  101  housing or carrying the conduit  126 . The conduit  126  is deployed by retrieving the elastically curved needle  101  into the rigid needle  220  while holding the plunger  109  stationary, as shown in  FIG. 6 . The conduit  126  is deployed at the endplate  105  bridging between the intervertebral disc  100  and the interior of the vertebral body  159 .  FIG. 7  shows the superior view of the endplate shunt  126  after retrieval of the elastically curved needle  101  into the rigid needle  220  to deploy the conduit  126 . The disc  100  is not shown in  FIG. 7 .  
         [0144]     Discs adjacent to spinal fusion often show rapid degeneration leading to recurrent back pain. Similarly, discs adjacent to a disc replacement may not have degenerated enough to be replaced, but may be vulnerable to becoming a source of recurrent back pain. Disc shunts or conduits  126  can be used in discs  100  adjacent to spinal fusions or disc replacements to slow, stop or reverse disc  100  degeneration.  
         [0145]     Many spinal fusion and disc replacement procedures use anterior approaches. Since the patient is already open, blood vessels  112  can be retracted to expose the vertebral body  159 , as shown in  FIG. 8 . A drill  150  is used to penetrate through the vertebral body  159  toward the center of the adjacent endplate  105 . The drill bit  150  contains a drill stop  279  to prevent drilling too deeply.  FIG. 9  shows a side view of a vertebral body  159  being drilled toward the center of the endplate  105 . The drill bit  150  is replaced by a straight needle  101  containing a conduit  126  abutted by a plunger  109 , as shown in  FIG. 10 . The conduit  126  is deployed, as shown in  FIG. 11 , by withdrawing the needle  101  while holding the plunger  109  stationary. The conduit  126  becomes an endplate shunt  126  for re-establishing the exchange of nutrients and waste between the interior of the vertebral body  159  and the disc  100 .  
         [0146]     PCT/US04/14368 (WO 2004/101015) by J. Yeung and T. Yeung on May 7, 2004, also proposed annular shunts  126  across the disc  100  to draw nutrients from the outer annulus into the inner annulus to feed the deprived cells. Annular shunts  126  can also be used to slow, stop or reverse degeneration of discs  100  adjacent to spinal fusion, disc replacement or vertebroplasty to minimize or prevent recurrent back pain.  
         [0147]     Pedicle  278  entry is currently being used to infuse bone cement or inflatable devices with a straight needle to repair vertebral fracture. The straight needle is as large as 11-gauge, about 3 mm diameter. The repair with bone cement is called vertebroplasty, which can be an out-patient procedure. Since the passage into the pedicle  278  can be as large as 3 mm in diameter, a stacking of a rigid needle  220 , an elastically curved needle  101 , a drill bit  150 , an endplate plug  292 , a plug sleeve  271  and conduit  126  can enter through the pedicle  278 . The elastically curved needle  101  is used to carve through the spongy cancellous bone within the vertebral body  159 , toward the calcified endplate  105 . The elastically curved needle  101  can curve superiorly or inferiorly to implant conduits  126  in the endplates  105  above and below the pedicle  278 .  
         [0148]     Calcified endplates  105  can be hard to puncture with a needle  101 . Flexible drill bits  150  are proposed for drilling through the endplate  105  prior to conduit  126  insertion. Since the thickness of cartilaginous endplate  105  is only between 0.5 and 2.5 mm, drilling through the endplate  105  is not difficult.  FIG. 12  shows a flexible drill bit  150  with cutting grooves  290 , strain-relieving elements  191 , shaft  300 , base  297 , grip  298  and fastener  299 . The strain-relieving elements  191  provide stress and strain relief when operating under curved or flexed conditions. The shaft  300  can be made thin to improve flexibility, as shown in  FIG. 13 . The shaft  300  can also be a coil, as shown in  FIG. 14 , to improve drilling capability in a curved condition. The base  297 , grip  298  and fastener  299  are used to mount the drill bit  150  to a drilling mechanism. The flexible drill bit  150  may also contain a widened section as a drill stop to prevent excessive depth of drilling. Drill depth can also be limited by the length of the drill bit  150 .  
         [0149]      FIG. 15  depicts a gear  301  with a drive hole  303  sized and configured to fit the grip  298  of the flexible drill bit  150 . The base  297  of the drill bit  150  is used to rest or press against the gear  301 . The grip  298  is inserted into the drive hole  303  of gear  301  and fastened by a wing nut  304  onto the fastener  299  of the drill bit  150 , as shown in  FIG. 16 . The gear  301  can be driven by a second gear  302  connecting to a crank handle  305 . Both gear  301  and the second gear  302  are engaged within a drill housing  306  held together by bolts  307  and nuts  308 , as shown in  FIG. 16 .  
         [0150]     The flexible drill bits  150  can be made with elastic alloy, such as nickel-titanium or spring tempered stainless steel. Since endplate  105  drilling is light duty, the drill bit  150  can be made with a polymer, such as poly-ether-ether-ketone, acetal resin, polysulfone, polycarbonate, polypropylene, polyethylene, polyamide or other suitable material.  
         [0151]     The drill bits  150  can be made by molding, CNC machining, water jet machining, grinding, centerless grinding or other technique. If the drill bit material is metallic, electric discharging machining can be used. The drill bit  150  can also be assembled from modular parts. The parts can be made with different materials to meet various physical requirements.  
         [0152]     Slits  309  are open at the distal end of the elastically curved needle  101 , as shown in  FIG. 17 . The curved needle  101  is deployed and positioned at the calcified endplate  105 . The flexible drill bit  150  is inserted into and guided by the curved needle  101  to drill through the calcified endplate  105 , as shown in  FIG. 18 . After drilling, the curved needle  101  advances into the drilled hole as the flexible drill bit  150  is withdrawn from the drilled hole. The slits  309  allow the diameter of the distal end of the needle  101  to partially collapse or narrow. The needle  101  is positioned at the drilled hole and partially penetrates into the endplate  105 , as shown in  FIG. 19 . A beveled  310  tip tapering or thinning at the outer surface, as shown in  FIG. 20 , facilitates needle  101  insertion into the drilled hole of the calcified endplate  105 . After fixation of the needle  101  at the endplate  105 , the drill bit  150  is withdrawn from the needle  101 .  FIG. 21  shows multiple slits  309  and a beveled  310  tip to further facilitate insertion into and fixation at the hole created at the calcified endplate  105 .  
         [0153]      FIG. 22  shows a conduit  126  abutting a flexible plunger  109  on a flexible slide  311  with a sharp distal end. The assembly of the conduit  126 , plunger  109  and flexible slide  311  is inserted into the curved needle  101  leading into the drilled hole of the calcified endplate  105  into the intervertebral disc  100 , as shown in  FIG. 23 . The conduit  126  is deployed at the calcified endplate  105  by withdrawing the slide  311  while holding the plunger  109  stationary, as shown in  FIG. 24 . The deployed conduit  126  bridges between the interior of the vertebral body  159  and the disc  100  to draw nutrients and oxygen from the vertebral body  159  and to feed the deprived cells in the disc  100 . In addition, during compressive loading, lactic acid produced within the disc  100  is expelled through the conduit  126  into bodily circulation to normalize the pH within the degenerative disc  100 .  
         [0154]     The slide  311  provides dual functions: (1) punctures the drill hole into the intervertebral disc  100 , and (2) smoothly deploys the conduit  126 . Braided material of the conduit  126  can bunch up and jam within a tubular structure, such as the needle  101 . The slide  311  provides a stationary semi-cylindrical surface for the conduit  126 , reducing the friction between the braided conduit  126  and the needle  101 . Hence, the possibility of bunching and jamming of the conduit  126  within the needle  101  is minimized. In addition, jamming of the conduit  126  within the needle  101  can be freed by rotating the slide  311 . The slide  311  can be made from a thin metal or alloy, such as nickel-titanium, stainless steel or spring tempered stainless steel. The slide  311  can also be made with polymer. The cross-section of the slide  311  can be a fraction of a circle, elliptical or another shape.  
         [0155]     An ultra thin and flexible tube can also be used to contain the conduit  126 , slide  311  and plunger  109 . The assembly of the ultra thin tube, conduit  126 , slide  311  and plunger  109  inserts into the needle  101 , through the drilled hole of the calcified endplate  105  into the disc  100 . The conduit  126  is deployed by withdrawing the ultra thin tube, followed by the slide  311  while holding the plunger  109  stationary.  
         [0156]     A thin, flexible drill sleeve  313  can be used to maintain the drilled position at the endplate  105 .  FIG. 25  shows the flexible drill sleeve  313  with a sharp distal end, sliding over the drill bit  150 .  FIG. 26  shows a modified slide  311  with a trough at the distal end, a plunger  109  within the lumen  312  of the tubular, proximal end of the slide  311 . After endplate  105  drilling, the flexible drill sleeve  313  slides over the drill bit  150  through the drilled hole into the disc  100 , as shown in  FIG. 27 . The drill bit  150  is replaced by the assembly of the conduit  126 , slide  311  and plunger  109 , as shown in  FIG. 28 . The drill sleeve  313  is retrieved, exposing the conduit  126  and the slide  311 , as shown in  FIG. 29 . The conduit  126  is then deployed at the calcified endplate  105  by withdrawing the slide  311  while holding the plunger  109  stationary.  
         [0157]     The flexible drill bit  150  can also contain cutting elements  315  and a lumen  314  for passing the conduit  126 , slide  311  and plunger  109 , as shown in  FIG. 30 .  FIG. 31  shows the proximal ends of the slide  311  and plunger  109  extending from the proximal end of the drill  150  assembly. The flexible drill  150  is guided by the elastically curved needle  101  to drill and cut through the calcified endplate  105  into the intervertebral disc  100 . The assembly of conduit  126 , slide  311  and plunger  109  inserts into the lumen  314  of the drill bit  150 , as shown in  FIG. 32 . The drill  150  is withdrawn, followed by the slide  311  while holding the plunger  109  stationary to deploy the conduit  126  at the calcified endplate  105 .  
         [0158]     Indentations of the drill shaft  300  in  FIG. 12  form the strain-relieving elements  191  for operating under curved or flexed conditions. The strain-relieving elements  191  of the drill  150  can also be a variety of openings.  FIG. 33  shows horizontal openings as strain-relieving elements  191 .  FIG. 34  shows longitudinal openings as strain-relieving elements  191 . The strain-relieving elements  191  can also be oriented in other directions.  FIG. 35  shows a trocar  103  clearing the debris cored out by the cutting elements  315  of the drill  150 . The trocar  103  or the assembly of conduit  126  and slide  311  can advance through the lumen  314  of the drill  150  by rotation to avoid snagging of the strain-relieving element  191 .  
         [0159]     Sealing the gap between the conduit  126  and the endplate  105  prevents immune responses to the nucleus content of the disc  100 . In addition, the sealing also preserves the hydrostatic pressure of the disc  100 , funneling the flow of nutrients and oxygen through the semi-permeable conduit  126  deep into the avascular disc  100 .  FIG. 36  shows a swellable coating  163  during hydration to seal the gap between the conduit  126  and the calcified endplate  105 .  FIG. 37  depicts an elastic or compressible cone-shaped endplate plug  292  with a lumen  295 . The wall of the plug  292  is tapered. The lumen  295  of the endplate plug  292  is sized to fit over the elastically curved needle  101 , as shown in  FIG. 38 . After the endplate  105  is punctured, a plug sleeve  271  pushes the plug  292  into the punctured hole of the calcified endplate  105 , as shown in  FIG. 39 . The needle is withdrawn while the sleeve  271  further advances the plug  292  to seal the gap between the conduit  126  and endplate  105 , as shown in  FIG. 40 . The conduit  126  is deployed by retrieving the elastically curved needle  101  while holding the plunger  109  stationary.  FIG. 41  depicts hydration and swelling of the plug  292  sealing the gap between the conduit  126  and the calcified endplate  105  to maintain isolation of the nucleus pulposus and preserve the hydrostatic pressure within the disc  100 .  
         [0160]      FIG. 42  shows another cone-shaped endplate plug  292  with a closable slit  293 . The plug  292  with the slit  293  can also be elastic, compressible and able to slide over the needle  101  by the plug sleeve  271 , as shown in  FIG. 43 . As the plug  292  slides off from the needle  101  into the hole of the endplate  105 , the slit  293  closes to provide a tight seal between the conduit  126  and the plug  292 , as shown in  FIG. 44 . The cone-shape and elasticity of the plug  292  provide a tight seal between the plug  292  and the calcified endplate  105 .  
         [0161]     The plug  292  can also contain ridges or self-tapping threads  294  and the slit  293 , as shown in  FIG. 45 . For plug  292  tightening, a nut  296  is formed at the proximal end of the plug  292 , as shown in  FIG. 46 . The slit  293  and lumen  295  extend the entire length of the endplate plug  292 , including the nut  296  portion. A plug sleeve  271  is sized and configured to fit over the nut  296  of the plug  292 , as shown in  FIG. 47 , to advance the plug  292  over the needle  101  by rotation into the calcified endplate  105 .  
         [0162]     The cross-section of the plug  292 , nut  296 , plug lumen  295 , needle  101  and conduit  126  is depicted in  FIG. 48 . After the plug  292  is advanced into the endplate  105 , the needle  101  is withdrawn and the slit  293  is closed, the lumen  295  of the plug  292  seals around the conduit  126 , as depicted in  FIG. 49 . Upon closure of the slit  293 , the cross-section of the nut  296  collapses or shrinks The cross-sectional shape of the nut  296  also becomes distorted or deformed, so the tight fit within the plug sleeve  271  is lost, as shown in  FIG. 50 . Hence continual rotation of the sleeve  271  will not excessively tighten or advance the plug  292  too deeply into the calcified endplate  105 . The cross-section of the nut  296  can be a triangle, square, pentagon, hexagon or other shape along with a matching shape for the sleeve  271  to prevent excessive endplate  105  tightening. The endplate plug  292  can be made with non-degradable or degradable material similar to the one used for the conduit  126 .  
         [0163]     Back pain may be caused by degeneration of multiple discs  100 , which may also explain the common recurrence of back pain shortly after spinal surgery. Many patients experience no pain relief at all after their surgeries. The sacral approach is proposed to implant a conduit  126  through multiple discs  100  using a minimally invasive technique. Punctures  152  can be made through the inferior fascia of the pelvic diaphragm  120 , anterior to the coccyx  137  and gluteus maximus muscle  139 . Two punctures  152  can be made at both sides of the anococcygeal body  138 , as shown in  FIG. 51 . The nerves  118  and blood vessels  112  are more abundant near the rectum  111 , anterior to the punctures  152 .  
         [0164]     The colon  119  above the inferior fascia of pelvic diaphragm  120  blocks instruments from entering into the pelvic. The colon  119  is supple, compliant and stretchable. Hence, repositioning of the colon  119  for insertion of instruments, with a blunt rod  144  through the rectum  111  is difficult, as shown in  FIG. 52 . A colon positioner  145  contains a tubular body  147 , a handle  148  connected to a vacuum line  149 , a suction cup  146  at or near a blunt and curved distal end, as depicted in  FIG. 53 . A channel within the body  147  connects the suction cup  146  to the vacuum line  149 . The suction cup  146  is located at the concave side of the distal curved portion of the positioner  145  for conforming to the direction and inner tissue of the colon  119 .  FIG. 54  shows the vacuum of the suction cup  146 , holding the inner lining of the colon  119  and lifting the colon  119  to provide entry to the blunt obturators  141  within the sheaths  230 . The obturators  141  advance with intermittent vacuum releases and advancements of the colon positioner  145 . The obturators  141  are replaced with a drill  150  and an endoscope  117 , as depicted in  FIG. 55 , drilling into vertebral bodies from S1 to possibly L3. The endoscope  117  is used to avoid puncturing of the median sacral artery and vein beneath the S1 vertebral body. The drill  150  is then replaced with a straight needle  101  containing a long conduit  126  abutting a plunger  109 , as depicted in  FIG. 56 . The conduit  126  is deployed by withdrawing the needle  101  while holding the plunger  109  stationary. Hence, the conduit  126  re-establishes the exchange of nutrients and waste for multiple discs  100 , as shown in  FIG. 57 .  
         [0165]     It is generally accepted that disc  100  degeneration is largely related to nutritional and oxygen deficiency. In the supine position, disc pressure is low. Nutrients are drawn into the disc  100  through the semi-permeable conduit  126  to produce the water retaining sulfated glycosaminoglycans and increase the swelling pressure within the disc  100 . Restoration of swelling pressure in the nucleus pulposus reinstates the tensile stresses within the collagen fibers of the annulus, thus reducing the inner bulging and shear stresses between annular layers. Similar to a re-inflated tire, disc  100  bulging is reduced and nerve impingement is minimized. The load on the facet joints  129  and segmental instability are reduced to ease wear and pain. Disc  100  height may increase to reverse spinal stenosis.  
         [0166]     In daily activities, such as walking and lifting, pressure within the disc  100  greatly increases. The direction of the flow is then reversed within the conduit  126 , flowing from high pressure within the disc  100  to low pressure within vertebral bodies  159 . The lactic acid and carbon dioxide dissolved in the fluid within the nucleus pulposus is slowly expelled through the conduit  126  into the vertebral bodies  159 , then to bodily circulation. As a result, the lactic acid concentration decreases, and pH within the disc  100  is normalized.  
         [0167]     Furthermore, due to the continual supply of oxygen into the disc  100  through the conduit  126 , lactic acid normally produced under anaerobic conditions may drastically decrease. Hence, the pain caused by acidic irritation to tissues, such as the posterior longitudinal ligament, superior  142  and inferior  143  articular processes of the facet joint  129 , may quickly dissipate. Buffering agents, such as bicarbonate, carbonate or other, can be loaded or coated on the conduits  126  to neutralize lactic acid upon contact and spontaneously ease the pain.  
         [0168]     Examples of conduit  126  material are included but are not limited to carboxymethyl cellulose, cellulose acetate, cellulose sulfate, cellulose triacetate, chitin, chitosan, chloroprene, ethylene-vinyl acetate, fluro-silicon hydrogel, hyaluronan, hyaluronate, neoprene, polyacrylamide, polyacrylate, polyacrylonitrile, poly-butylene terephthalate, poly-dimethyl-siloxane, poly-hydroxy-ethyl-acrylate, poly-hydroxy-ethyl-methacrylate, poly-hydroxy-methyl methacrylate, polymethacrylate, polymethylmethacrylate, polypropylene oxide, poly-siloxane, polyvinyl alcohol, poly-vinylpyrrolidone, silanol and vinyl methyl ether.  
         [0169]     The endplate conduit  126  and the annular conduit  126  described in PCT/US2004/14368 (WO 2004/101015) may have different pore sizes to limit permeability. In addition, pore sizes may differ creating various permeabilities within sections of the conduit  126 . The pore sizes of the conduit  126  may decrease toward the section near the nucleus pulposus  128  to minimize immune responses to the nucleus pulposus without excluding large nutrients from coming into or metabolites from going out of the middle portion of the annulus. Hence, the conduit  126  can have a permeable gradient from 200000, 100000, 70000, 50000, 30000, 10000, 5000, 3000, 1000 to 700 molecular weights of solutes. The pore sizes of the permeable gradient of the conduit  126  can range from 301 μm, 100 μm, 50 μm, 10 μm, 1 μm, 700 nm, 500 nm, 300 nm, 100 nm, 50 nm, 30 nm, 10 nm, 5 nm to 1 nm to prevent infiltration of IgA, IgD, IgE, IgG, IgM, cytokines or other initiators.  
         [0170]     Excessive immune response to the conduit  126  and/or the nucleus pulposus  128  is often undesirable. Fibrous formation over the conduit  126  may affect the exchange of nutrients and waste between the disc  100  and bodily circulation. Exposure of the nucleus pulposus  128  may cause inflammation. Immuno inhibitor can be coated or incorporated into the conduit  126  to minimize fibrous formation or tissue response. Examples of immuno inhibitors include but are not limited to: aminopterin, azathioprine, chlorambucil, corticosteroids, crosslinked polyethylene glycol, cyclophosphamide, cyclosporin A, 6-mercaptopurine, methylprednisolone, methotrexate, niridazole, oxisuran, polyethylene glycol, prednisolone, prednisone, procarbazine, prostaglandin, prostaglandin E 1 , steroids, other immune suppressant drug or other immune suppressant coating.  
         [0171]     Hydrostatic pressure within the shunted disc  100  can be preserved by a swellable and semi-permeable coating over the conduit  126  to seal around the gap between the conduit  126  and annulus or between the conduit  126  and endplate  105 . The swellable coating can be polyethylene glycol, crosslinked polyethylene glycol, polyurethane or other swellable material.  
         [0172]     In addition, an initial supply of nutrients, such as magnesium trisilicate, magnesium mesotrisilicate, magnesium oxide, Magnosil, Pentimin, Trisomin, orthosilicic acid, magnesium trisilicate pentahydrate, Serpentine, sodium metasilicate, silanolates, silanol group, sialic acid, silicic acid, hydroxylysine, hydroxylproline, serine, threonine, boron, boric acid, glucose, glucuronic acid, galactose, galactosamine and/or glucosamine, can be used to coat the conduit  126  to enhance or initiate the production of sulfated glycosaminoglycans and collagen within the degenerative disc  100 .  
         [0173]     Healthy intervertebral discs  100  are avascular and immuno-isolated. To ensure the avascular and immuno-isolated conditions, conduits  126  can be incorporated, coated or partially coated with an anti-angiogenic compound. Examples of anti-angiogenic compounds are included but are not limited to Marimastat from British Biotech [a synthetic inhibitor of matrix metalloproteinases (MMPs)], Bay 12-9566 from Bayer (a synthetic inhibitor of tumor growth), AG3340 from Agouron (a synthetic MMP inhibitor), CGS 27023A from Novartis (a synthetic MMP inhibitor), COL-3 from Collagenex (a synthetic MMP inihibitor. Tetracycline® derivative), Neovastat from Aetema, Sainte-Foy (a naturally occurring MMP inhibitor), BMS-275291 from Bristol-Myers Squib (a synthetic MMP inhibitor), TNP-470 from TAP Pharmaceuticals, (a synthetic analogue of fumagillin; inhibits endothelial cell growth), Thalidomide from Celgene (targets VEGF, bFGF), Squalamine from Magainin Pharmaceuticals (Extract from dogfish shark liver; inhibits sodium-hydrogen exchanger, NHE3), Combretastatin A-4 (CA4P) from Oxigene, (induction of apoptosis in proliferating endothelial cells), Endostatin collagen XVIII fragment from EntreMed (an inhibition of endothelial cells), Anti-VEGF Antibody from Genentech, [Monoclonal antibody to vascular endothelial growth factor (VEGF)], SU5416 from Sugen (blocks VEGF receptor signaling), SU6668 from Sugen (blocks VEGF, FGF, and EGF receptor signaling), PTK787/ZK 22584 from Novartis (blocks VEGF receptor signaling), Interferon-alpha from (inhibition of bFGF and VEGF production), Interferon-alpha from (inhibition of bFGF and VEGF production), EMD121974 from Merck KcgaA (small molecule blocker of integrin present on endothelial cell surface), CAI from NCI (inhibitor of calcium influx), Interleukin-12 from Genetics Institute (Up-regulation of interferon gamma and IP-10), IM862 from Cytran, Avastin, Celebrex, Erbitux, Herceptin, Iressa, Taxol, Velcade, TNP-470, CM101, Carboxyamido-triazole, Anti-neoplastic urinary protein, Isotretionin, Interferon-alpha, Tamoxifen, Tecogalan combrestatin, Squalamine, Cyclophosphamide, Angiostatin, Platelet factor-4, Anginex, Eponemycin, Epoxomicin, Epoxy-β-aminoketone, Antiangiogenic antithrombin III, Canstatin, Cartilage-derived inhibitor, CD59 complement fragment, Fibronectin fragment, Gro-beta, Heparinases, heparin hexasaccharide fragment, Human chorinonic gonadotropin, Interferon (alpha, beta or gamma), Interferon inducible protein (IP-10), Interleukin-12 (IL-12), Kringle 5 (plasminogen fragment), Tissue inhibitors of metalloproteinases, 2-Methoxyestradiol (Panzem), Placental ribonuclease inhibitor, Plasminogen activator inhibitor, Prolactin 16 kD fragment, Retinoids, Tetrahydrocortisol-S, Thrombospondin-1, Transforming growth factor beta, Vasculostatin, and Vasostatin (calreticulin fragment).  
         [0174]     It is to be understood that the present invention is by no means limited to the particular constructions disclosed herein and/or shown in the drawings, but also includes any other modification, changes or equivalents within the scope of the claims. Many features have been listed with particular configurations, curvatures, options, and embodiments. Any one or more of the features described may be added to or combined with any of the other embodiments or other standard devices to create alternate combinations and embodiments. The elastically curved needle  101  can be called the resilient needle  101 . The rigid needle  220 , needle  101  or drill sleeve  313  can be generally described in the claims as a sheath with a lumen. The vertebral body  159  can be called vertebrae.  
         [0175]     It should be clear to one skilled in the art that the current embodiments, materials, constructions, methods, tissues or incision sites are not the only uses for which the invention may be used. Different materials, constructions, methods, coating or designs for the conduit  126  can be substituted and used. Nothing in the preceding description should be taken to limit the scope of the present invention. The full scope of the invention is to be determined by the appended claims.