Abstract:
An orthopedic surgical kit for inserting a biological material into the cancellous portion of bone by a minimally invasive technique has several components which are manually operated using a universal handle. The kit includes a docking needle used as a guide for placing a cannula in a bone. The cannula is filled with a biological material, for support or treatment of the bone, and the material is expressed from the cannula by a plunger.

Description:
FIELD OF THE INVENTION 
     This invention relates to the orthopedic field of vertebroplasty and to the apparatus and process for injecting biological material into the cancellous portion of bones for treatment and support. 
     BACKGROUND OF THE INVENTION 
     Vertebroplasty was introduced to the medical arts as a percutaneous technique for repairing spinal compression fractures by injecting bone cement into the vertebral body. However, the technique quickly expanded to osteoporotic individuals that had been treated with narcotics and immobilization. The bone cement is used to shore up the collapsing vertebrae for support which relieves the pain associated with undue pressure on the nerves. 
     Radiologists and surgeons are involved in the procedure since the process is monitored by fluoroscopy and has the potential for leakage of the cement into the local blood stream. Some of the critical parameters of the procedure involve the mixing of the cement to an appropriate viscosity, ensuring that the cement is radio-dense for viewing, properly placing the injector inside the cancellous portion of a vertebra, and rigorously controlling injection pressure and quantity. See “Vertebroplasty: Dangerous Learning Curve,” START-UP, Jun. 2001. 
     DESCRIPTION OF THE PRIOR ART 
     U.S. Pat. No. 6,273,916 to Murphy describes vertebroplasty, generally, as performed on a prepped and draped prone patient who has been injected with a local anaesthetic. A skin incision is made over the selected vertebrae and a needle is inserted in a posterior approach to engage the vertebral body. A suitable cement is prepared using a contrast medium, such as barium powder, mixed with methylmethacrylate powder, and a monomer liquid. The cement (PMMA) becomes unworkable within 4 to 11 minutes from mixing. 
     Cement is injected into the vertebrae, while visualized by lateral and anterior- posterior X-ray projection fluoroscopy imaging. The injection is halted if the cement starts to extend into unwanted locations, such as the disc space or towards the posterior quarter of the vertebral body where the risk of epidural venous filling and spinal cord compression is greatest. If no unwanted migration is detected, the injection continues until the vertebrae is adequately filled. The amount of cement injected may vary considerably, e.g. from 4 to 36 cc. 
     Reiley et al, U.S. Pat. No. 6,048,346, teach a posterior-lateral approach for accessing the interior of the vertebrae for injecting bone cement or treatment substances or a combination of both. The bone cement is injected using a caulking gun-like device with a ram rod in the barrel. 
     Goldenberg et al, U.S. Pat. No. 5,634,473, and Goldenberg, U.S. Pat. No. 5,843,001, both teach a removable handle for biopsy needles used for bone biopsy. 
     What is needed in the art is a simple apparatus having several components operated by the same handle to perform biopsy and inject high viscosity cement or other biological material or a combination of both in precisely measured quantities. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an objective of the instant invention to teach a kit for biopsy and injection of biological materials having a guide needle, cannulas, several different cannula tips, a plunger, a clearing tool, a connector and a universal tool. 
     It is a further objective of the instant invention to teach a kit for biopsy and injection of biological materials which is sized to deliver a precise amount of biological material. 
     It is another objective to teach a kit with several interchangeable tips to be fitted on the leading end of the cannula for different penetrations of the bone. 
     It is yet another objective of the instant invention to teach a procedure for delivery of a biological material at high viscosity and low pressure. 
     It is a still further objective of the invention to teach a kit for orthopedic use to perform bone biopsy and to deliver a biological material to the cancellous portion of bone. 
     Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES 
     FIG. 1 is a perspective of the docking needle and a cannula removably telescoped together; 
     FIG. 2 is a cross section of the telescoped docking needle and cannula taken along line A—A of FIG. 1; 
     FIG. 3 is a longitudinal cross section of a cannula and a plunger; 
     FIG. 4 is a perspective of the cannula and clearing tool assembly; 
     FIG. 5 is a longitudinal cross section of the cannula and clearing tool taken along line B—B of FIG. 4; 
     FIG. 6 is a perspective of the biopsy instrument; 
     FIG. 7 is a side view of the hex Luer-type fitting; 
     FIG. 8 is a top plan view of the handle with the docking needle engaged; 
     FIG. 9 is a perspective of the handle with the needle and plunger engaged; 
     FIG. 10 is a perspective of the handle with the docking needle engaged; 
     FIG. 11 is a perspective of a modification of the delivery cannula tip; 
     FIG. 12 is a perspective of another modification of the delivery cannula tip; and 
     FIG. 13 is a perspective of another modification of the delivery cannula tip. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The orthopedic system of this invention is in the form of a kit which includes a docking needle  10  with an elongated shaft  11 , shown in FIGS. 1 and 2, having an insertion point  12  for penetration through the cutaneous layer of a patient. The point  12  passes through the skin, muscle and the hard shell of a bone into the softer cancellous bone material. The point  12  forms a tapered end portion with the base of the taper  13  smoothly merging into the shaft  11 . 
     The needle is of a size and material to withstand the compression required for insertion without deformation. The needle may be made of stainless steel, other metals, or suitable polymers. Normally, the insertion is performed manually by axial pressure at the trailing end  14  of the needle to include striking the needle with a surgical hammer. The tool or handle  50 , shown in FIGS. 8,  9 , and  10  is designed to fit on the trailing end  14  of the needle for translating the manual axial pressure to the needle  10 . 
     Preferably, in vertebroplasty, the needle  10  is inserted on a posterior-lateral tract, using X-ray fluoroscopy, to dock in a vertebrae anteriorly of the lateral process. Other approaches may be chosen by the surgeon. Regardless, of the orthopedic surgical procedure involved, the docked needle serves as a guide for the subsequent insertion of the cannulas of the system. Of course, in some applications, the needle and cannula may be inserted simultaneously. 
     In operation, a cannula is telescoped over the docking needle  10  to provide a pathway for removal or delivery of material from the bone. The surgeon removes the handle  50  from the trailing end of the docking needle and connects the handle with the trailing end of the cannula. The leading end of the cannula is then placed over the trailing end of the needle. Axial pressure is applied to the cannula to slide the cannula along the needle to the desired location. Using fluoroscopy, the surgeon telescopes the cannula over the docking needle until the leading end of cannula and the leading end of the docking needle are flush or superimposed within the bone site thereby designating proper placement of the delivery cannula. 
     FIGS. 1 and 2 show a delivery cannula  15  telescoped over the docking needle. The leading end  16  of the cannula may be tapered to form a smooth transition from the needle point to the cannula shaft  17 . In one embodiment, the delivery cannula is included in a kit without an attached leading end. The leading end  16  is selected and placed on the shaft to provide a range of choices to the surgeon. The trailing end  18  of the cannula has a connector  80  either removably affixed by internal threads  82 , in the nature of a Leur-type fitting, or permanently connected to the shaft. The connector  80  has external planar surfaces  81  which provide a gripping surface for manipulating the cannula. In one embodiment, the connector has a hex-nut outer surface to prevent rotation within handle  50  although other configurations are a matter of choice. The connector  80  has a reduced diameter portion  83  between a shoulder  84  and a flange  85  to prevent longitudinal movement within the handle  50 . 
     Once the cannula is telescoped over the needle to the desired location within the bone, the handle is removed from the trailing end of the cannula and re-attached to the trailing end of the needle which extends beyond the trailing end of the cannula. Axial force is then applied in the opposite direction to remove the needle from the bone and the cannula. After the needle has been removed, the cannula bore  19  is open for either removing material for biopsy or for dispensing a biological material for treatment. 
     FIG. 6 shows a biopsy cannula  20  with a leading end having serrations  21 . Of course, the leading end  16  of the delivery cannula  15  may be modified to enhance the ability to cut through bone, also, as shown in FIGS. 11-13. Once the biopsy cannula  20  has been manipulated either rotationally or longitudinally or both by the handle  50  engaged with the connector  80 , the handle is used to withdraw the cannula from the patient&#39;s body. A clearing tool  22 , shown in FIGS. 4 and 5, is inserted into the bore  23 . The clearing tool  22  is advanced through the bore to push the tissue sample from the cannula. 
     If a biopsy is not required or after removal of the biopsy cannula, a delivery cannula  15  is telescoped over the docking needle, as described above. The delivery cannula is provided with a connector  80  at its trailing end. The longitudinal dimension of the connector is such that it fits within a recess  61  in the handle  50 . 
     The tool or handle  50 , illustrated in FIGS. 8,  9  and  10 , is made from surgical stainless steel or other magnetizable or non-magnetizable metals, or, preferably, molded from a high impact polymer, such as polyethylene, polypropylene, NYLON or similar compositions capable of withstanding repeated sterilizations. The handle is flexible and, preferably, resilient. The handle has a top surface  51 , a bottom surface  52  and side walls defining a periphery  53 . A slit  54  extends through the side walls from the periphery toward the center portion  60 . The slit has opposing jaws  55  and  56  which pivot about the center portion. The jaws  55  and  56  each have a bore  63  and  64 , respectively, oriented in the same plane in which each jaw pivots. 
     Another slit  57  extends through the side walls from the periphery toward the center portion. Slit  57  has opposing jaws  58  and  59  which pivot about the center portion  60 . The jaws  58  and  59  each have a flange for engaging the reduced diameter portion of the connector  80 . 
     By applying pressure on the opposing pairs of jaws of each slit, the jaws may approach with each other. When pressure is released, the respective pairs of jaws resiliently move away from each other. As illustrated, the slits are arranged to oppose each other. 
     A blind bore  62  is formed in the periphery of the handle for the purpose of engaging the trailing end of the docking needle. The shaft of the blind bore  62  is shaped to cooperate with the trailing end of the needle to provide rotation of the needle upon rotation of the handle. The surgeon manually grips the handle and applies longitudinal and/or rotational force through the handle to the needle to penetrate the soft tissue and bone of the patient. The handle may also provide a striking plate for receiving blows from a surgical hammer for driving the needle into the bone. Once the needle is properly docked in the bone, the handle is removed from the needle. 
     Blind bore  65  is of suitable size to accommodate the trailing end of the cannula fitted with a connector  80 . As shown in FIG. 8, the blind bore  65  has a larger diameter terminating with a shoulder  66  which will engage and stop the connector  80 . A smaller diameter portion  67  of the bore continues above the shoulder to allow the trailing end of the docking needle to extend beyond the trailing end of the connector  80 . Because the cannula is somewhat larger than the docking needle, the tip of the cannula may be sharpened to cut through the bone. A surgical hammer may be used to drive the delivery cannula, at least, through the hard outer shell of the bone. Once the cannula is located in the cancellous portion of the bone, the cannula may be removed from the blind bore  65 . 
     The cannula with an attached connector  80  may then placed in the slit  57 , of the handle, with the connector  80  in recess  61 . The connector  80  is engaged with the jaws  58  and  59  to prevent longitudinal or rotational movement of the cannula within the handle. The surgeon telescopes the leading end of the cannula over the trailing end of the needle and again applies longitudinal force through the handle to the cannula to force the cannula through soft tissue and into the bone. As the cannula approaches the proper position in the bone, the trailing end  14  of the telescoped docking needle emerges from the trailing end of the cannula. When the trailing end of the needle  14  is level with the top surface  51  of the handle, the leading end  16  of the cannula is flush with the end of the needle. The top surface  51  of the handle and the trailing end  14  of the needle serve as a visual and tactile gauge, in the surgeon&#39;s hand, for properly placing the leading end of the cannula in the bone. 
     The handle  50  is then removed from the cannula and the jaws of slit  54  are pivoted to place the bores  63  and  64  in parallel. The trailing end of the needle is then inserted through bores  63  and  64 . The pivoting pressure on jaws  55  and  56  is then released causing the bores to resiliently intersect engaging the shaft of the needle, as shown in FIG.  8 . Of course, the tool  50  may operate in reverse, with the pivoting pressure causing the jaws to close, in another embodiment. The needle is then removed from the cannula by use of the handle  50 . After the needle is removed from the cannula the jaws are pivoted to release the shaft of the needle and free the handle. 
     In FIGS. 11,  12 , and  13 , alternate removable tips  16 A,  16 B and  16 C are shown. The kit may be supplied with several interchangeable tips to provide the surgeon with flexibility in dealing with anomalies of the bones or individual preference. Also, if a larger diameter delivery cannula is needed for the proper amount of biological substance, a relatively smaller tip can be used to penetrate the bone. In FIG. 11, the delivery cannula  15  has a removable tip  91  with a necked down portion  92  and a smaller leading end portion  93  that penetrates the hard outer shell of the bone. 
     FIG. 12 shows another tip  16 B that is tapered to a leading end  94  with serrations  95  which may be necessary to cut through the dense bone. 
     FIG. 13 illustrates another tip  16 C which has a tapered leading end and a closed point  98 . The tapered tip has screw threads  96  for auguring into bone. The delivery port  97  is on the lateral aspect of the leading end. 
     Other replaceable tips  16  may have other shapes or a variety of cannulas may be furnished with permanent tips. 
     The delivery cannula is now positioned to transmit the biological material to the bone. In general, the biological substance may be either structural or a treating agent or a combination of both. 
     For example, the material may be selected from such groups of substances as BMP, bone morphogenic proteins, DBM, demineralized bone matrix, BOTOX and other viral vectors, any bone marrow aspirate, platelet rich plasma, composite ceramic hydroxyapatite, tricalcium phosphate, glass resin mixtures, resorbable highly purified polylacttides/polylactides-co-glycolides and others. The treating agent may include hormonal, antibiotic, anti-cancer, or growth factor substances, among others. In vertebroplasty, polymethylmethacrylate (PMMA) is the customary bone cement though other compounds may be used. 
     Regardless of the chemical make-up of the biological substance, this system preferably uses a high viscosity biological material delivered through the cannula at a low pressure. To accomplish this objective, after the delivery cannula is properly placed in the bone, it is filled with a biological material having a viscosity allowing it to flow into the cannula. The viscosity of some of the materials continues to increase within the cannula to reach a consistency acceptable to the surgeon. Other materials may be ready for use, when loaded in the cannula. 
     When the material is sufficiently stiff, the surgeon inserts a plunger  24  into the cannula  15  to express the biological substance into the cancellous portion of the bone. The plunger  24  is fitted with a connector  80  and manipulated by handle  50 . As shown in FIG. 3, both the plunger  24  and the cannula  15  are telescoped together and the plunger is sized to substantially co-terminate with the leading end of the delivery cannula when both the connectors  80  are in contact. The diameter of the plunger is slightly less than the diameter of the cannula to provide a vent for the system. The viscosity of the biological material will be such that the entire amount of the material will be expressed from the cannula. In this instance, the amount of biological material delivered is precisely measured to be the corresponding volume of the delivery cannula, for example, 4 cc. 
     Of course, the amount of biological material may be adjusted to a particular patient. This is accomplished through the continued fluoroscopic observance of the procedure. If more material is necessary in a particular procedure, the syringe used to load the delivery cannula may be utilized to pre-load the bone cavity before the plunger is inserted into the delivery cannula. 
     When the appropriate amount of biological material has been injected into the bone, the handle  50  is used to rotate and withdraw the plunger  24 . Once the biological substance has begun to solidify, the handle is placed on the delivery cannula and twisted to rotate the cannula thereby separating the cannula from the substance. The cannula is subsequently withdrawn from the bone. 
     It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and drawings.