Abstract:
The intervertebral disc contains no blood vessels. Nutrients and waste are diffused mainly through adjacent vertebral bodies. As we age, calcified layers form between the disc and vertebral bodies, blocking diffusion. The disc begins to starve and flatten. The weight shifts abnormally from disc to the facet joints causing strain and back pain. Under anaerobic conditions, lactic acid is produced causing acidic irritation and unspecific pain. A U-shaped disc shunt ( 126 ) is delivered into and sealed within the degenerated disc simply by needle puncturing and withdrawal, to draw nutrients from bodily circulation into the avascular disc. A continual supply of nutrients increases biosynthesis of the water-retaining sulfated glycosaminoglycans, hence swelling pressure within the disc. The weight is re-shifted from the facet joints to the regenerated disc, alleviating back pain. With oxygen transported through the shunt, anaerobic production of lactic acid is minimized. In addition, the residual lactic acid is expelled through the U-shaped shunt during disc compression into bodily circulation to alleviate unspecific pain.

Description:
FIELD OF INVENTION 
       [0001]    The disc shunt is used to re-establish the exchange of nutrients and waste between the avascular disc and bodily circulation to alleviate back pain. This invention relates to a U-shaped disc shunt and delivery device to preserve hydrostatic disc pressure, simplify delivery and increase permeability of nutrients into the avascular disc. 
       BACKGROUND 
       [0002]    Low back pain is a leading cause of disability and lost productivity. Up to 90% of adults experience back pain at some time during their lives. For frequency of physician visits, back pain is second only to upper respiratory infections. In the United States, this malady disables 5.2 million people, and the economic impact has been reported to be as high as $100 billion each year. Though the sources of low back pain are varied, in most cases the intervertebral disc is thought to play a central role. Degeneration of the disc initiates pain in other tissues by altering spinal mechanics and producing non-physiologic stress in surrounding tissues. 
         [0003]    The intervertebral disc absorbs most of the compressive load of the spine, but the facet joints of the vertebral bodies share 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 absorbing sulfated glycosaminoglycans (chondroitin and keratan sulfate), creating the swelling pressure to provide tensile stress within the collagen fibers of the annulus. The swelling pressure produced by high water content is crucial to supporting the annular layers for sustaining compressive loads. 
         [0004]    In adults, the intervertebral disc is avascular. Survival of the disc cells depends on diffusion of nutrients from external blood vessels and capillaries through the cartilage of the endplates. Diffusion of nutrients also permeates from peripheral blood vessels adjacent to the outer annulus, but these nutrients can only permeate up to 1 cm into the annular layers of the disc. An adult disc can be as large as 5 cm in diameter; hence diffusion through the cranial and caudal endplates is crucial for maintaining the health of the nucleus pulposus and inner annular layers of the disc. 
         [0005]    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, which form into bone. Bone formation at the endplate increases with age. 
         [0006]    When the endplate is obliterated by bone, diffusion of nutrients through the calcified endplate is greatly limited. In addition to hindering the diffusion of nutrients, calcified endplates further limit the permeation of oxygen into the disc. Oxygen concentration at the central part of the nucleus is extremely low. Cellularity of the disc is already low compared to most tissues. To obtain necessary nutrients and oxygen, cell activity is restricted to being on or in very close proximity to the cartilaginous endplate. Furthermore, oxygen concentrations are very sensitive to changes in cell density or consumption rate per cell. 
         [0007]    The supply of sulfate into the nucleus pulposus for biosynthesizing sulfated glycosaminoglycans is also restricted by the calcified endplates. As a result, the sulfated glycosaminoglycan concentration 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 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. 
         [0008]    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. 
         [0009]    When oxygen concentration in the disc falls below 0.25 kPa (1.9 mmHg), production of lactic acid dramatically increases with increasing distance from the endplate. The pH within the disc falls as lactic acid concentration increases. Lactic acid diffuses through micro-tears of the annulus irritating the richly innervated posterior longitudinal ligament, facet joint and/or nerve root. Studies indicate that lumbar pain correlates well with high lactate levels and low pH. The mean pH of symptomatic discs was significantly lower than the mean pH of normal discs. Acid concentration is three times higher in symptomatic discs than normal discs. In symptomatic discs with pH 6.65, the acid concentration within the disc is 5.6 times the plasma level. In some preoperative symptomatic discs, nerve roots were found to be surrounded by dense fibrous scars and adhesions with remarkably low pH 5.7-6.30. The acid concentration within these discs was 50 times the plasma level. 
         [0010]    Approximately 85% of patients with low back pain cannot be given a precise pathoanatomical diagnosis. This type of pain is generally classified under “non-specific pain”. Back pain and sciatica can be recapitulated by maneuvers that do not affect the nerve root, such as intradiscal saline injection, discography, and compression of the posterior longitudinal ligaments. It is possible that some of the non-specific pain is caused by lactic acid irritation secreted from the disc. Injection into the disc can flush out the lactic acid. Maneuvering and compression can also drive out the irritating acid to produce non-specific pain. Currently, no intervention other than discectomy can halt the production of lactic acid. 
         [0011]    In the presence of oxygen, metabolism of each glucose molecule produces 36 adenosine triphosphates, ATP, through glycolysis, citric acid cycle and electron transport chain. ATP is a high-energy compound essential for driving biosynthesis of the water-retaining proteoglycans. Under anaerobic conditions, the metabolism of each glucose molecule produces only 2 ATP and two lactic acids. Hence, production of high-energy compound ATP is low under anaerobic conditions within the disc. 
         [0012]    The nucleus pulposus is thought to function as “the air in a tire” to pressurize the disc. To support the load, the pressure effectively distributes the forces evenly along the circumference of the inner annulus and keeps the lamellae bulging outward. The process of disc degeneration begins with calcification of the endplates, which hinders diffusion of sulfate and oxygen into the nucleus pulposus. As a result, production of the water absorbing sulfated glycosaminoglycans is significantly reduced, and the water content within the nucleus decreases. The inner annular lamellae begin to sag inward, and the tension on collagen fibers within the annulus is lost. The degenerated disc exhibits unstable movement, similar to 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. In addition, pH within the disc becomes acidic from the anaerobic production of lactic acid, which irritates adjacent nerves and tissues. 
         [0013]    The method of endplate puncturing for drawing nutrients from the vertebral body to regenerate the degenerated disc is described in PCT/US2002/04301 (WO 2002/064044) by J. Yeung and T. Yeung filed on Feb. 13, 2002 with US Provisional application 60/268666 filed on Feb. 13, 2001. 
         [0014]    Shunts or 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. Nos. 10/840,816 by J. Yeung and T. Yeung, both applications filed on May 7, 2004. U.S. provisional patent application 60/626,644, filed on Nov. 10, 2004 by Jeffrey E. Yeung also described several disc shunt (conduit) configurations and delivery devices. 
         [0015]    Discs L4-5 and L5-S1 are shielded by the iliac, inaccessible 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/US2005/22749 (WO 2006/002417), filed on Jun. 22, 2005 by J. Yeung, can puncture through the calcified endplate to deliver the shunt or conduit for exchanging nutrients and lactate between the avascular disc and bodily circulation. 
         [0016]    Chemical or physical modification of the disc shunt was proposed in PCT/US2006/44795, filed on Nov. 17, 2006 by James E. Kemler and Jeffrey E. Yeung for enhancing, selecting or delaying molecular transport into and out of the avascular disc. 
         [0017]    By re-supplying the disc cells with nutrients and oxygen through disc shunt or conduit, biosynthesis of sulfated glycosaminoglycans may increase to retain additional water and sustain compressive loading. Hence, segmental instability and excessive loading of facet joints are minimized to alleviate back pain. With the presence of additional oxygen, production of lactic acid may decrease to minimize acidic irritation and increase production of ATP, driving biosynthesis of the water-retaining proteoglycans. 
       SUMMARY OF INVENTION 
       [0018]    One end of a U-shaped shunt is inserted into the lumen of a needle while the other end is draped outside the needle. As the needle punctures into a disc, the outside strand of the shunt is squeezed beside the outside wall of the needle, pressing into the annulus through a very small punctured hole. During needle withdrawal, the friction between the outside strand and the annulus grips the U-shaped shunt, allowing the inside strand to slide out the lumen of the needle to deploy the U-shaped shunt within the disc. Since the U-shaped shunt is tightly press-fitted into the elastic annulus, hydrostatic pressure is preserved within the shunted disc. 
         [0019]    Another U-shaped shunt can be linked to the outside strand to increase (1) friction for shunt deployment, (2) press-fit capacity, and (3) rate of nutrient and waste exchange to regenerate the intervertebral disc. Additives, buffer, nutrients, growth factor and cells can also be incorporated into the U-shaped shunts to expedite disc regeneration and alleviate back pain. 
       REFERENCE NUMBER 
       [0000]    
       
           100  Intervertebral disc 
           101  Needle 
           103  Trocar 
           105  Endplate 
           108  Calcified layer or blockade 
           114  Annular delamination 
           126  U-shaped disc shunt or conduit 
           128  Nucleus pulposus 
           129  Facet joint 
           150  Drill 
           159  Vertebral body 
           230  Sleeve needle 
           269  Lumen of needle 
           278  Pedicle 
           279  Drill stop or step 
           360  Stem 
           362  Indentation of the stem 
           363  Bevel of the stem 
           364  Body of the stem 
           366  Edge of the stem 
           367  Restriction device 
           368  Sharp inner wall of needle 
           369  Damage portion of the shunt 
           370  Dull, round or blunt inner wall of the needle 
           371  Slit of the needle 
           372  Protrusion or anchor of U-shaped shunt 
           373  Link or attached shunt 
           403  Prong 
       
     
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0048]      FIG. 1  shows a portion of disc shunt  126  extending from the lumen  269  and draping over the outside wall of a needle  101 . 
           [0049]      FIG. 2  depicts needle  101  puncturing to press-fit the shunt  126  into annular layers of the intervertebral disc  100  to preserve hydrostatic disc pressure. 
           [0050]      FIG. 3  shows withdrawal of the needle  101  to deploy the shunt  126  within and extending from the disc  100 . 
           [0051]      FIG. 4  depicts a longitudinal view of the shunt  126  with a damaged portion  369  cut by the sharp inner wall  368  of the needle  101  during disc  100  puncturing. 
           [0052]      FIG. 5  shows a rounded or blunt inner wall  370  at the lumen  269  opening to prevent shearing or damaging the shunt  126  during disc  100  puncturing. 
           [0053]      FIG. 6  shows a slit  371  opened from the lumen  269 , forming a step or indentation to shield the shunt  126  from shearing during disc  100  puncturing. 
           [0054]      FIG. 7  shows a cross section of the disc shunt  126 , inside and outside the needle  101 . Deployment of disc shunt  126  depends primary on the friction between the annulus and the section of disc shunt  126  outside the needle  101 . 
           [0055]      FIG. 8  shows an anchor or tapered protrusion  372  on the outside portion of the shunt  126  to add friction and assist shunt  126  deployment during withdrawal of the needle  101 . 
           [0056]      FIG. 9  shows a needle  101  with a triangular cross section. The needle  101  is sharpened, beveling to one side of the triangle. 
           [0057]      FIG. 10  shows a cross section of the triangular needle  101  and disc shunt  126  extending from the lumen  269  and draping over a vertex of the triangle to minimize friction between the shunt  126  and needle  101 . 
           [0058]      FIG. 11  shows a link shunt  373  threaded through or connected to the portion of disc shunt  126  outside the needle  101 . 
           [0059]      FIG. 12  shows a cross section of the needle  101 , shunt  126  and link shunt  373  to increase transport of nutrients into the avascular disc and friction essential for shunt deployment. 
           [0060]      FIG. 13  shows the needle  101 , shunt  126  and link shunt  373  puncturing and press-fitting into the annular layers to preserve hydrostatic pressure of the disc  100 . 
           [0061]      FIG. 14  depicts spreading or kinking of the link shunt  373  to add friction between the link shunt  373  and annulus during withdrawal of the needle  101 . 
           [0062]      FIG. 15  shows deployment of the shunt  126  and link shunt  373  by withdrawing the needle  101  to re-establish the exchange of nutrients and waste between the avascular disc  100  and bodily circulation. 
           [0063]      FIG. 16  shows a guided trocar  103  puncturing through soft tissue into the pedicle  278 . 
           [0064]      FIG. 17  shows a sleeve needle  230  inserted over the trocar  103  into the pedicle  278 . 
           [0065]      FIG. 18  shows replacement of the trocar  103  with a drill  150  in the sleeve needle  230 , drilling through the calcified endplate  105  into the degenerated disc  100 . 
           [0066]      FIG. 19  shows advancement of the sleeve needle  230  sliding over the drill bit  150  into the drilled hole of the calcified endplate  105 . 
           [0067]      FIG. 20  shows withdrawal of the drill  150 , leaving the tip of the sleeve needle  230  within the drilled hole of the calcified endplate  105 . 
           [0068]      FIG. 21  shows endplate  105  puncture through the sleeve needle  230  by a needle  101  to press-fit the linked shunts  126 ,  373  into the disc  100 . 
           [0069]      FIG. 22  shows withdrawal of the sleeve needle  230  to allow tissue contact with the linked shunts  126 ,  373  for friction assisted shunt deployment. 
           [0070]      FIG. 23  shows deployment of the linked shunts  126 ,  373  by withdrawing the needle  101  to connect the avascular disc  100  with the interior of the vertebral body  159  to re-establish nutrients and waste exchange. 
           [0071]      FIG. 24  shows an anterior approach using similar drilling procedure to puncture and deploy the linked shunts  126 ,  373  connecting the avascular disc  100  and the vertebral body  159 . 
           [0072]      FIG. 25  shows a U-shaped shunt  126  supported between prongs  403  extended from a stem  360 . 
           [0073]      FIG. 26  shows the lumen  269  of a needle  101  housing the U-shaped shunt  126 , prongs  403  and stem  360 , for puncturing and delivering the shunt  126  into a disc  100 . 
           [0074]      FIG. 27  shows a U-shaped shunt  126  delivered by disc  100  puncturing and withdrawing the needle  101  shown in  FIG. 26 , while holding the stem  360  stationary. 
           [0075]      FIG. 28  shows an indentation  362  at the distal end of the stem  360  to support the U-portion of the shunt  126 . 
           [0076]      FIG. 29  shows a U-shaped shunt  126  supported by the flexible stem  360  within the lumen  269  of an elastically curved needle  101  puncturing through the calcified endplate  105 . 
           [0077]      FIG. 30  shows a cross section of two U-shaped shunts  126  supported by a square-like stem  360  within the lumen  269  of a needle  101 . 
           [0078]      FIG. 31  shows a restriction device  367  holding the two U-shaped shunts together within a needle  101 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0079]    Disc shunt  126  is a flexible and semi-permeable conduit transporting nutrients, waste and oxygen between bodily circulation and the avascular disc  100 . The disc shunt  126  is bent into a U- or V-configuration. The lengths of the bent portions do not have to be equal. One end of the U-shaped shunt  126  is inserted into the lumen  269  of a thin needle  101  while the other end of the U-shaped shunt  126  is draped over the outside wall of the thin needle  101 , as shown in  FIG. 1 . 
         [0080]    Since diffusion of nutrients can only penetrate up to 1 cm into the annular layers, the U-shaped disc shunt  126  is delivered deep into the annulus by puncturing the disc  100  with the needle  101 , as shown in  FIG. 2 . As the needle  101  punctures into the disc  100 , the outside strand of the U-shaped shunt  126  is pulled, dragged and tightly pressed against the annular layers beside the outside wall of the needle  101  through a small puncture hole. During needle  101  withdrawal, the contact friction between the annulus and the outside strand of the U-shaped shunt  126  holds or anchors the shunt  126 , allowing the inside strand to slide out the lumen  269  of the needle  101 , as shown in  FIG. 3 . Since one strand is press-fitted within a small puncture, the U-shaped shunt  126  is well sealed within the elastic annular layers to preserve the hydrostatic pressure of the disc  100 . 
         [0081]      FIG. 3  shows that the U-loop of the shunt  126  is deployed within the disc  100  with the proximal ends of the shunt  126  extending outside the disc  100 , in contact with bodily circulation. As a result, the exchange of nutrients, oxygen and lactic acid between the avascular disc  100  and bodily circulation is re-established to (1) increase biosynthesis of the water-retaining sulfated glycosaminoglycans and swelling pressure for sustaining disc compression, (2) decrease strain on the facet joints and pain from segmental instability, (3) lower production of the irritating lactic acid by converting anaerobic to aerobic metabolism, (4) increase production of ATP through the aerobic metabolism pathway to energize disc  100  regeneration, and (5) expel lactic acid through the shunt  126  to minimize irritation. In essence, the U-shaped disc shunt  126  is deployed to halt disc  100  degeneration and alleviate back pain. 
         [0082]    One leg, portion or end of the U-shaped shunt  126  occupies the lumen  269  inside the needle  101  while the other leg, portion or end hangs outside the needle  101 . The inside portion of the shunt  126  is free to exit the lumen  269  of the needle  101 . The wall of the needle  101  at the distal end provides support to the U-loop of the shunt  126  for disc  100  puncturing. In addition to providing friction for shunt  126  deployment, the outside portion of the shunt  126  is pressed or squeezed beside or along the needle  101  wall as it enters the annulus. Hence, the U-shaped shunt  126  is delivered through a very small needle puncture hole. After needle  101  withdrawal, the elastic annular layers seal around the deployed and press-fitted shunt  126  to preserve the hydrostatic pressure of the disc  100 . 
         [0083]    The sharp distal end of the needle  101  usually contains a sharp knife-like edge  368  formed by the inner wall of the beveled lumen  269 , as shown in  FIG. 4 . When the disc  100  is punctured during implantation of the press-fitting U-shaped shunt  126 , the knife-like edge of the inner wall  368  inevitably shears and damages the U-loop of the shunt  126 . The damaged portion  369  of the shunt  126  forms small fibers or shedding debris, which causes significant tissue reaction to the otherwise inert material. During in-vitro studies, shearing was so serious that many U-shaped shunts  126  were severed at the U-loops during press-fit disc  100  puncturing. As a result, the inside portion of the shunt  126  remained within the lumen  269  of the withdrawn needle  101 . With only one strand of the U, the shunt  126  was no longer press-fitting into the intervertebral disc  100 , so it decreased its ability to preserve the hydrostatic pressure of the disc  100 . 
         [0084]      FIG. 5  shows a rounded or blunt inner wall  370  at the beveled lumen  269  of a needle  101 . The rounded or blunt inner wall  370  can be formed by machining to prevent damage to the shunt  126  during press-fit disc  100  puncturing, as shown in  FIG. 5 . It is also possible to pad, cover, coat or fortify the U-loop of the U-shaped shunt  126  to minimize damage by the sharp inner wall  368  of the needle  101 . In addition, the U-loop can be made with a shear-proof material to avoid damage during press-fit puncturing. 
         [0085]      FIG. 6  shows a slit  371  opened into the lumen  269  placing the U-loop of the shunt  126  further away from the sharp tip of the needle  101 . The additional separation between the sharp tip and the U-loop facilitates disc  100  puncture by setting up sequential press-fit positions to gradually enlarge the puncture site. The needle  101  tip spearheads the entry followed by the U-loop into the annular layers of the intervertebral disc  100 . In addition, gradual enlargement of the puncture site may minimize shearing or damage to the U-shaped shunt  126  during disc  100  puncture. Entrenching or shielding the U-loop in the slit  371  may further protect the shunt  126  from shearing during press-fit entry into the disc  100 . In addition, the sharp knife-like edge  368  formed by inner wall of the indented lumen  269  of the needle  101  can also be rounded or made blunt to further prevent damage to the U-shaped shunt  126 . 
         [0086]    Deployment of the U-shaped shunt  126  is driven by the friction between the annulus and the outside portion of the shunt  126 .  FIG. 7  shows a cross section of the inside and outside portions of the shunt  126  relative to the needle  101 . The friction between the annulus and the outside portion of the shunt  126  can increase significantly by attaching an anchor or tapered protrusion  372  on the outside portion of the shunt  126 , as shown in  FIG. 8 . The tapered protrusion  372  functions as a barb, allowing entry but preventing shunt  126  pull out from the disc  100 . 
         [0087]    Deployment of the U-shaped shunt  126  also depends on the friction between the outside portion of the shunt  126  and outside wall of the needle  101 .  FIG. 9  shows a needle  101  with a triangular cross section. The triangular needle  101  is sharpened to bevel toward one vertex of the triangle. The outside strand of U-shape shunt  126  is aligned with the outside edge of this vertex of the triangular needle  101 .  FIG. 10  shows a cross section of the triangular needle  101  and the U-shaped shunt  126  extending from the lumen  269  and draping over the triangular vertex to minimize contact surface and friction between the shunt  126  and needle  101 . The needle  101  with a round or non-round cross section can also be lubricated inside and outside to decrease friction between the needle  101  and the shunt  126  for facilitating shunt  126  deployment during withdrawal of the needle  101 . In addition, the outside portion of the shunt  126  can be coated with adhesive, swelling agent or crosslinking agent for disc  100  anchoring prior to needle  101  withdrawal. 
         [0088]      FIG. 11  shows a link shunt  373  threaded through or attached to the outside portion of the U-shaped shunt  126 . The combination of U-shaped shunt  126  and link shunt  373  increases mass to (1) allow rapid exchange of nutrients and waste between the degenerative disc  100  and bodily circulation, (2) seal and preserve hydrostatic disc  100  pressure, and/or (3) anchor within the disc  100  for deployment during needle  101  withdrawal.  FIG. 12  shows a cross section of the needle  101 , shunt  126  and link shunt  373 . The linked shunt  373  can differ from the U-shaped shunt  126  by having different (1) material, (2) pore size, (3) coating, (4) additives, (5) configuration, (6) diameter, (7) length, (8) shape, (9) texture, and/or (10) degradation profile. 
         [0089]      FIG. 13  shows the needle  101  delivering the shunt  126  and link shunt  373  to press-fit into the annular layers and preserve hydrostatic pressure of the disc  100 . The link shunt  373  can attach anywhere along the outside portion of the shunt  126 . To position the sequential press-fit, attachment of the link shunt  373  should be slightly behind or away from the U-loop of the shunt to ease disc  100  puncture. In addition to aiding shunt  126  deployment, the link shunt  373  provides additional sealing capacity within the annulus to preserve hydrostatic pressure of the repaired disc  100 . 
         [0090]    The link shunt  126  is likely to shift, buckle, kink and/or spread to add friction to the disc  100  during needle  101  withdrawal, as shown in  FIG. 14 . Similar movement and friction may apply to the outside portion of the U-shaped shunt  126 . As a result, the inside portion of the shunt  126  slides and exits from the lumen  269  of the withdrawn needle  101 , deploying both the linked shunts  126 ,  373  as shown in  FIG. 15 , to re-establish the exchange of nutrients and waste between the avascular disc  100  and surrounding circulation. 
         [0091]      FIG. 16  shows a trocar  103 , guided by fluoroscopes, puncturing soft tissue into the pedicle  278 . The trocar  103  can be coated with radiopaque, echogenic or MRI visible coating to assist guidance and enhance imaging.  FIG. 17  shows a sleeve needle  230  inserted over the trocar  103  sliding into the pedicle  278 . The sleeve needle  230  can also be coated with radiopaque, echogenic, MRI coating or other coating for image enhancement. 
         [0092]    The sleeve needle  230  is held stationary, while the trocar  103  is withdrawn and replaced with a drill bit  150 , drilling through the vertebral body  159  and calcified endplate  105 , as shown in  FIG. 18 . The drill bit  150  contains a step or stop  279  to prevent excessive drilling through both endplates  105  of the disc  100 . The drill bit  150  can also be coated with radiopaque, echogenic, MRI coating or other coating for image enhancement. The sleeve needle  230  is then advanced to slide over the drill bit  150  into the drilled hole of the calcified endplate  105 , as shown in  FIG. 19 . 
         [0093]    The drill bit  150  is withdrawn from the sleeve needle  230 , leaving the tip of the sleeve needle  230  within the drilled hole of the calcified endplate  105 , as shown in  FIG. 20 . The needle  101  of the linked shunts  126 ,  373  is inserted through the sleeve needle  230 , puncturing and enlarging the drilled hole of the calcified endplate  105  and press-fitting into the degenerative disc  100 , as shown in  FIG. 21 . Both the needle  101  and linked shunts  126 ,  373  can be coated with radiopaque, echogenic, MRI coating or other coating for image enhancement.  FIG. 22  shows withdrawal of the sleeve needle  230  to allow tissue contact with the linked shunts  126 ,  373  for friction assisted shunt deployment.  FIG. 23  shows deployment of the linked shunts  126 ,  373  by withdrawing the needle  101 , thus connecting the avascular disc  100  to the interior circulation of the vertebral body  159  and re-establishing the exchange of nutrients, oxygen and waste. 
         [0094]    Recurrent back pain is common among post-surgical patients. The pain often comes from progressive disc degeneration adjacent to the surgical levels. During surgeries for anterior spinal fusion or disc replacement, degeneration of the adjacent disc  100  can be minimized or halted by implanting disc shunts  126 ,  373  through the endplate  105 .  FIG. 24  shows an anterior approach using a drilling procedure similar to the pedicle approach. The linked shunts  126 ,  373  are implanted through the vertebral body  159  into the avascular disc  100  adjacent to the surgical level. Since the patient is already undergoing an open surgery, implantation of disc shunts  126 ,  373  through the endplate  105  or through the annulus is straight forward, low risk and cost effective to minimize recurrent pain or future surgery. Similarly, laminectomy or other posterior open surgical approaches also provide easy access for implanting annular or endplate shunts  126  into multiple degenerative discs  100 . 
         [0095]    The vertebral body  159  and endplate  105  of the patient may be soft enough for trocar  103  puncture. The trocar  103  can be tapped or lightly hammered through the vertebral body  159  and endplate  105  into the disc  100 . The sleeve needle  230  is then inserted over the trocar  103 , advanced into the endplate  105  and the disc  100 . The trocar  103  is replaced by the U-shaped shunts  126 ,  373  and needle  101 , as shown in  FIG. 21 . 
         [0096]    The U-shaped shunt  126  can also be delivered completely within the lumen  269  of a needle  101 .  FIG. 25  shows a U-shaped shunt  126  supported between prongs  403  extending from a stem  360 . The U-shaped shunt  126 , prongs  403  and stem  360  are housed within the lumen  269  of a needle  101 , as shown in  FIG. 26 , capable of puncturing an intervertebral disc  100 . After disc  100  puncturing, the needle  101  is withdrawn while holding the stem  360  stationary to deploy the U-shaped shunt  126  within the disc  100 , as shown in  FIG. 27 . Annular delamination  114  from decreased swelling disc pressure is also shown in  FIG. 27 . 
         [0097]      FIG. 28  shows an indentation  362  for supporting the U-loop of the shunt  126 . The ribbon-like stem  360  is thin to minimize space within the lumen  269  of the needle  101 . The body  364  is thickened beyond the bevels  363  to strengthen the stem  363 .  FIG. 29  shows a U-shaped shunt  126  supported by a flexible stem  360  housed within the lumen  269  of an elastically curved needle  101  puncturing through a calcified layer  108  and cartilaginous endplate  105 . The disc shunt  126  is deployed across the calcified endplate  105  from the vertebral body  159  into the disc  100  by withdrawing the needle  101  while holding the stem  360  stationary. 
         [0098]    Multiple U-shaped shunts  126  can be delivered from the lumen  269  of the needle  101  and supported by a shape conforming stem  360 , as shown in  FIG. 30 . The stem  360  can have longitudinal edges  366  to align the shunts  126  and prevent intertwining or tangling within the lumen  269 . The distal ends or the U-loops of the multiple shunts  126  can have a restriction device  367 , as shown in  FIG. 31 , to keep the U-shaped shunts  126  from unraveling and jamming within the lumen  269  of the needle  101 . Similarly, multiple U-shaped shunts  126  can also be housed both inside and outside of the lumen  269  of the needle  101  to press-fit multiple U-shaped shunts  126  into a degenerative disc  100 . 
         [0099]    It is generally accepted that disc  100  degeneration is largely related to nutritional and oxygen deficiency. Especially in the supine position, disc pressure is low. During sleep, fluid from circulatory containing nutrients and oxygen is drawn through the shunt  126 ,  373  by (1) capillary action, (2) water absorbency of the shunt, (3) imbibing pull of the water-absorbing sulfated glycosaminoglycans within the disc  100 , and/or (4) low pressure within the disc  100 . 
         [0100]    As a result, nutrients are drawn into the disc  100  through the semi-permeable shunt  126 ,  373  to biosynthesize the water retaining sulfated glycosaminoglycans and increase the swelling pressure within the disc  100 . Restoration of swelling pressure in the nucleus pulposus  128  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 minimize strain, wear and pain. Disc  100  height may also increase to reverse spinal stenosis. 
         [0101]    Furthermore, adenosine triphosphate, ATP, is the high-energy compound essential for driving or energizing biochemical reactions, including the biosynthesis of the water retaining proteoglycans for sustaining compressive loads on the disc  100 . Under anaerobic conditions, metabolism of each glucose molecule produces only two ATP and two lactic acids, which irritate the adjacent nerves. When oxygen permeates through the U-shaped shunt  126  and/or link shunt  373 , thirty-six ATP are produced from each glucose molecule through glycolysis, citric acid cycle and electron transport chain under aerobic conditions to energize disc  100  regeneration and alleviate back pain. 
         [0102]    In daily activities, such as walking, lifting and bending, pressure within the disc  100  greatly increases. The direction of the flow within the disc shunt  126 ,  373  is likely to reverse and flow from high pressure within the disc  100  to low pressure within vertebral bodies  159  or external fluid surrounding the disc  100 . The lactic acid and carbon dioxide dissolved in the fluid within the nucleus pulposus  128  will slowly expel through the shunt  126  into bodily circulation. As a result, the lactic acid concentration will decrease, and pH within the disc  100  will normalize to reduce or alleviate pain from acid irritation. 
         [0103]    Sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, calcium carbonate, barium carbonate, potassium phosphate, sodium phosphate or other buffering agent can be loaded in or coated on the shunt  126 ,  373  to neutralize lactic acid and spontaneously alleviate pain caused by acid irritation. 
         [0104]    Similarly, magnesium oxide, magnesium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide, cesium hydroxide, strontium hydroxide, calcium hydroxide, lithium hydroxide, rubidium hydroxide, neutral amines or other alkaline agent can be loaded in or coated on the shunt  126 ,  373  to neutralize lactic acid and spontaneously alleviate pain caused by acid irritation. 
         [0105]    In addition, an initial supply of nutrients, such as sulfate, glucose, glucuronic acid, galactose, galactosamine, glucosamine, hydroxylysine, hydroxylproline, serine, threonine, chondroitin sulfate, keratan sulfate, hyaluronate, magnesium trisilicate, magnesium mesotrisilicate, magnesium oxide, Magnosil, Pentimin, Trisomin, orthosilicic acid, magnesium trisilicate pentahydrate, Serpentine, sodium metasilicate, silanolates, silanol group, sialic acid, silicic acid, boron, boric acid, minerals and/or other amino acids can be used to coat or load the shunts  126 ,  373  as additives to enhance or initiate the production of sulfated glycosaminoglycans and collagen within the degenerative disc  100 . Growth factor, antibiotic, analgesic may also be helpful to load into or coat on the shunts  126 ,  373 . 
         [0106]    Hydrostatic pressure within the shunted disc  100  can be further preserved by a swellable and semi-permeable coating over the U-shaped shunts  126 ,  373  to seal the gap between the shunt  126 ,  373  and annulus or between the shunt  126 ,  373  and endplate  105 . The swellable coating can be polyethylene glycol, crosslinked polyethylene glycol, polyurethane, swellable or elastic materials. 
         [0107]    Fibrous formation over the shunts  126 ,  373  may affect the exchange of nutrients and waste between the disc  100  and bodily circulation. Immuno inhibitor can be coated or incorporated into the shunts  126 ,  373  to minimize fibrous formation or tissue response. Examples of immuno inhibitors include but are not limited to: actinomycin-D, aminopterin, azathioprine, chlorambucil, corticosteroids, crosslinked polyethylene glycol, cyclophosphamide, cyclosporin A, 6-mercaptopurine, methylprednisolone, methotrexate, niridazole, oxisuran, paclitaxel, polyethylene glycol, prednisolone, prednisone, procarbazine, prostaglandin, prostaglandin E 1 , sirolimus, steroids, other immune suppressant drugs or other immune suppressant coatings. 
         [0108]    The U-shaped shunts  126 ,  373  can be loaded or coated with a calcium channel blocker to minimize calcification, mineralization or blockade of the shunts  126 ,  373 . The calcium channel blocker can also disperse from the shunt  126 ,  373  to prevent formation of or even open calcified layers of the cartilaginous endplate  105 , to enhance diffusion of nutrients and waste between the disc  100  and bodily circulation. The calcium channel blocker can be one of the dihydropyridines, phenylalkylamines, benzothiazepines or others. The calcium channel blocker for loading into the shunt  126 ,  373  can be Amlodipine, Felodipine, Isradipine, Lacidipine, Lercanidipine, Nicardipine, Nifedipine, Nimodipine, Nisoldipine, Verapamil, Diltiazem or other calcium channel blocker. 
         [0109]    The U-shaped shunts  126 ,  373  can be loaded or coated with a chelating agent to minimize calcification, mineralization or blockade of the shunts  126 ,  373 . The chelating agent can also disperse from the shunt  126 ,  373  to extract calcium ion, opening calcified layers of the cartilaginous endplate  105  to enhance diffusion of nutrients and waste between the disc  100  and bodily circulation. The chelating agent can be ethylene diamine tetra acetate, diethylene triamine penta acetate, meso-2,3-dimercapto succinic acid, desferoxamine, 2,3-dimercapto-1-propane sulfonate, D-penicillamine, defarasirox, dimercaprol, N,N-bis(carboxymethyl)glycine, morpholine dithiocarbamate, tetra ammonium ethylene diamine diacetic acid dithiocarbamate, ammonium diethanolamine dithiocarbamate, sodium diethyl dithio carbamate, N-benzyl-D-glucamine dithio carbamate, alpha lipoic acid, tartaric acid, glutathione, methionine and/or L-arginine. In general, the coating of chelating agent of the shunts  126 ,  373  can contain a carboxylated group, amine group or thiol group. Sodium or potassium carboxylate is preferred to minimize acidic irritation during extraction of calcium ion from the calcified endplate  105 . 
         [0110]    The U-shaped shunts  126 ,  373  may have pore sizes ranging from 301 μm to 1 nm. The U-shaped shunts  126 ,  373  may also have a length-wise gradient of various pore sizes to limit permeability. The pore sizes of the permeable gradient of the shunts  126 ,  373  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 triggering an immune reaction. 
         [0111]    In addition, the U-shaped shunts  126 ,  373  may have sections containing different pore sizes to create regions of size exclusion or permeabilities along the shunts  126 ,  373 . The pore sizes of the shunts  126 ,  373  may decrease toward the section near the nucleus pulposus  128  to minimize immune responses to the nucleus pulposus  128  without excluding large nutrients from coming into or metabolites from going out of the middle portion of the annulus. Hence, the shunts  126 ,  373  can have permeable regions ranging from 200000, 100000, 70000, 50000, 30000, 10000, 5000, 3000, 1000, 700, 400 to 200 gram per mole of solutes. 
         [0112]    Healthy intervertebral discs  100  are avascular and immuno-isolated. To ensure avascular and immuno-isolated conditions, the shunts  126 ,  373  can be incorporated, coated or partially coated with an anti-angiogenic compound. Examples of anti-angiogenic compounds include, 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 inhibitor. Tetracycline® derivative), Neovastat from Aeterna, 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), Squal amine 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 XVII fragment from EntreMed (an inhibition of en dothelial 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 (inhibition of bFGF and VEGF production), Interferon-alpha (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, TNP470, 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). 
         [0113]    A wide range of non-degradable materials can be used to fabricate the U-shaped shunt  126  and link shunt  373 . Biocompatible polymers, such as Nylon, polytetrafluoroethylene, polypropylene, polyethylene, polyamide, polyester, polyurethane, silicon, poly-ether-ether-ketone, acetal resin, polysulfone, polycarbonate, silk, cotton, or linen are possible candidates. Fiberglass can also be a part of the shunt  126 ,  373  to provide capillarity for transporting nutrients and waste. 
         [0114]    Part of the shunt  126 ,  373  can include one of the following materials, but is not limited to carboxymethyl cellulose, cellulose acetate, cellulose sulfate, cellulose triacetate, chitin, chitosan, chloroprene, ethylenevinyl acetate, fluoro-silicon hydrogel, hyaluronan, hyaluronate, neoprene, polyacrylamide, polyacrylate, polyamide, 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. 
         [0115]    For investigative purposes, a biodegradable shunt  126 ,  373  may show efficacy within weeks or months. Since the shunt  126 ,  373  degrades within months, any unforeseen adverse outcome would be nullified or negated. If the investigative-degradable shunt  126 ,  373  shows efficacy, a permanent or non-degradable shunt  126 ,  373  can then be installed to provide continuous treatment or benefits. The biodegradable shunt  126 ,  373  can be made with polylactate, polyglycolic, poly-lactide-co-glycolide, polycaprolactone, trimethylene carbonate, silk, catgut, collagen, poly-p-dioxanone or combinations of these materials. Other degradable polymers, such as polydioxanone, polyanhydride, trimethylene carbonate, poly-beta-hydroxybutyrate, polyhydroxyvalerate, poly-gama-ethyl-glutamate, poly-DTH-iminocarbonate, poly-bisphenol-A-iminocarbonate, poly-ortho-ester, polycyanoacrylate or polyphosphazene can also be used. 
         [0116]    The shunt  126 ,  373  can be a suture with a proven safety record. The shunt  126 ,  373  can be formed by molding, extruding, braiding, weaving, coiling, spiraling or machining. The shunt  126 ,  373  can also be called or classified as a conduit, wick, tube, braided suture, braided filaments, thread or sponge. The disc  100  installed with the shunt  126 ,  373  can be called the shunted disc  100 . 
         [0117]    The needle  101 , trocar  103 , sleeve needle  230  and stem  360  can be made with stainless steel, titanium, nickel-titanium or other alloy. The needle  101 , trocar  103 , sleeve needle  230 , stem  360  or shunt  126 ,  373  can be coated with lubricant, analgesic, antibiotic, radiopaque, echogenic or MRI visible agent. 
         [0118]    Disc cells can be drawn from another disc  100  within the patient to inject with a syringe into the shunted disc  100  to expedite disc regeneration. Gene therapy can also be done in the shunted disc  100  to promote disc regeneration. 
         [0119]    Since cellularity within discs  100  is always low, the shunted disc  100  can be further revitalized by injection of donor cells from an external source to expedite regeneration. The avascular disc  100  is well sealed. Even small ions, such as sulfate, and small molecules, such as proline, are greatly limited from diffusing into the nucleus pulposus  128 . The well-sealed disc  100  may be able to encapsulate donor cells from a disc  100  of a human cadaver without triggering an immune response. For disc  100  regeneration, the donor cells can also be stem cells, notochord or chondrocytes from tissue cultures, animals or biotechnology. Cells sensitive to sterilization can be loaded aseptically. The method for injecting donor cells into a shunted disc  100  can be done in multiple stages, separated by days, weeks, months or even years. Initial shunt  126 ,  373  deployment prepares the biological conditions, including pH, electrolytic balance and nutrients, to favor cell proliferation before cell injection. Donor cells can also be encapsulated within biodegradable capsules, seeded within the shunt  126 ,  373  and released after suitable biological conditions have been attained or achieved by the U-shaped shunt  126 ,  373 . 
         [0120]    In recent years, cell transplants from cadavers or live donors have been successful in providing therapeutic benefits. For example, islet cells from a donor pancreas are injected into a type I diabetic patient&#39;s portal vein leading into the liver. The islets begin to function as they normally do in the pancreas by producing insulin to regulate blood sugar. However, to keep the donor cells alive, the diabetic patient requires a lifetime supply of anti-rejection medication, such as cyclosporin A. In addition to the cost of anti-rejection medication, the long-term side effects of these immuno-suppressive drugs include cancer. The benefit of cell transplant may not out weigh the potential side effects. 
         [0121]    The shunted disc  100  with the semi-permeable shunt  126 ,  373  can be used as a semi-permeable capsule to encapsulate therapeutic donor cells. The shunted disc  100  maintains immuno-isolation for the donor cells to evade immuno-response of the patient. In addition, nutrients and oxygen essential for the donor cells are supplied through the U-shaped shunts  126 ,  373 . Hence, the need for immuno-suppressive medication is avoided. A variety of donor cells can be harvested and/or cultured from the pituitary gland (anterior, intermediate or posterior lobe), hypothalamus, adrenal gland, adrenal medulla, fat cells, thyroid, parathyroid, pancreas, testes, ovary, pineal gland, adrenal cortex, liver, renal cortex, kidney, thalamus, parathyroid gland, ovary, corpus luteum, placenta, small intestine, skin cells, stem cells, gene therapy, tissue engineering, cell culture, other glands or tissues. The donor cells can be from humans, animals or cell cultures. In supine sleeping position, nutrients and oxygen are supplied through the shunt  126 ,  373  to the donor cells. During waking hours while the pressure within the disc  100  is high, products biosynthesized by these cells are expelled through the shunt  126 ,  373  into the vertebral bodies  159  or outer annulus, then into the veins, bodily circulation and target sites, when and where the demands are high during waking hours. 
         [0122]    The product biosynthesized by the donor cells within the shunted disc  100  can be adrenaline, adrenocorticotropic hormone, aldosterone, androgens, angiotensinogen (angiotensin I and II), antidiuretic hormone, atrial-natriuretic peptide, calcitonin, calciferol, cholecalciferol, calcitriol, cholecystokinin, corticotropin-releasing hormone, cortisol, dehydroepiandrosterone, dopamine, endorphin, enkephalin, ergocalciferol, erythropoietin, follicle stimulating hormone, γ-aminobutyrate, gastrin, ghrelin, glucagon, glucocorticoids, gonadotropin-releasing hormone, growth hormone-releasing hormone, human chorionic gonadotrophin, human growth hormone, insulin, insulin-like growth factor, leptin, lipotropin, luteinizing hormone, melanocyte-stimulating hormone, melatonin, mineralocorticoids, neuropeptide Y, neurotransmitter, noradrenaline, oestrogens, oxytocin, parathyroid hormone, peptide, pregnenolone, progesterone, prolactin, pro-opiomelanocortin, PYY-336, renin, secretin, somatostatin, testosterone, thrombopoietin, thyroid-stimulating hormone, thyrotropin-releasing hormone, thyroxine, triiodothyronine, trophic hormone, serotonin, vasopressin, or other therapeutic products. 
         [0123]    The products (hormones, peptides, neurotransmitter, enzymes, catalysis or substrates) generated within the shunted disc  100  may be able to regulate body functions including blood pressure, energy, neuro-activity, metabolism, activation and suppression of gland activities. Some hormones and enzymes govern, influence or control eating habits and utilization of fat or carbohydrates. These hormones or enzymes may provide weight loss or gain benefits. Producing neurotransmitters, such as dopamine, adrenaline, noradrenaline, serotonin or γ-aminobutyrate from the donor cells within the shunted disc  100  can treat depression, Parkinson&#39;s disease, learning disability, memory loss, attention deficit, behavior problems, metal or neuro-related disease. 
         [0124]    Release of the products biosynthesized by the donor cells within the shunted disc  100  is synchronized with body activity. During activities of daily living, the pressure within the shunted disc  100  is mostly high to expel the products biosynthesized by the donor cells into circulation to meet the demands of the body. In the supine position, the flow within the shunt  126 ,  373  reverses, bringing nutrients and oxygen into the disc  100  to nourish the cells. Using islets of Langerhans from the donor&#39;s pancreas as an example, production of insulin will be induced in the shunted disc  100  during sleeping hours when glucose enters into the disc  100 . During waking hours when disc pressure is high, insulin will be expelled through the shunt  126 ,  373  into circulation to draw sugars into cell membranes for energy production. At night, the insulin released from the shunted disc  100  will be minimal to prevent hypoglycemia. In essence, products biosynthesized by the donor cells will be released concurrent with physical activity to meet the demands of the body. 
         [0125]    Some biosynthesized products from the donor cells are appropriately deposited through the vertebral body  159 , then into bodily circulation. Other products may be more effectively transported through the outer annulus and diffused through the abdomen into bodily circulation. Some other products may be far more effective by entering into the muscles connected to the U-shaped disc shunt  126 ,  373 . 
         [0126]    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. 
         [0127]    It should be clear to one skilled in the art that the current chemicals, biochemicals, drugs, methods, embodiments, materials, constructions, cells, tissues or incision sites are not the only uses for which the invention may be used. Different chemicals, constructions, methods, coating or designs for the modified U-shaped disc shunt  126 ,  373  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.