Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/70—Spinal positioners or stabilisers, e.g. stabilisers comprising fluid filler in an implant
  • A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
  • A61B17/7002—Longitudinal elements, e.g. rods
  • A61B17/7011—Longitudinal element being non-straight, e.g. curved, angled or branched
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/16—Instruments for performing osteoclasis; Drills or chisels for bones; Trepans
  • A61B17/17—Guides or aligning means for drills, mills, pins or wires
  • A61B17/1703—Guides or aligning means for drills, mills, pins or wires using imaging means, e.g. by X-rays
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
  • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/72—Intramedullary devices, e.g. pins or nails
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/16—Instruments for performing osteoclasis; Drills or chisels for bones; Trepans
  • A61B17/17—Guides or aligning means for drills, mills, pins or wires
  • A61B17/1725—Guides or aligning means for drills, mills, pins or wires for applying transverse screws or pins through intramedullary nails or pins

Definitions

• the present invention relates to apparatus for high intensity illumination with a light wand. More particularly, it relates to a light delivery structure useful in apparatus for efficient delivery of light by an intramedullary transillumination apparatus for accurate placement of distal locking screws during the procedure of long bone intramedullary nailing (also known as intramedullary rodding) .
• the invention also relates to methods for producing such light delivery structures .
• the distal locking light is a medical device designed for use in orthopedic surgery where a hollow pin is inserted into a fractured bone and then anchored in place by insertion of a screw from the side through both bone and pin .
• Pins used in this application have pre-drilled screw holes which are concealed within the bone . Up until the introduction of the distal locking light, x-rays taken on two axes were required to reveal the location of the hole so that the bone could be drilled and the pin inserted.
• the distal locking light allows the hole to be illuminated from behind by inserting this thin rod into the hollow pin with light emitting from a small aperture on one side.
• the bent fiber design can suffer from significant loss of fiber due to breakage in manufacturing, corresponding to an inconsistent and low light output . Since it is
• the fibers may intersect the aperture angled toward the end of the device .
• the resulting light pattern on the surface of the bone may be offset from the actual hole location in the pin, providing deceptive information about its exact location.
• individual fibers intersecting the cylindrical surface of the aperture may thus be polished at an angle, rather than the optimal flat preferred for controlled light distribution in fiber optics .
• the mirror design suffers a loss at the reflective interface formed by the optical fiber epoxy and the stainless steel mirror. Performance of this reflective surface is highly dependent on its texture and any residual films . Adhesion between the epoxy and the mirror is critical to light transmission, but also results in internal stresses . Epoxy has a much higher coefficient of thermal expansion than stainless steel, so that stresses built up during autoclave sterilization, which is required before use in surgery, can degrade the interface at the mirror reducing light output. Further, selection of an epoxy from the commercially available materials to optimize this bond to the mirror is limited by the requirements for light transmission and medical compatibility .
• This new design utilizes total internal reflection to direct the light from its axial path down the housing to a new path at 90 degrees through the aperture in the side of the housing.
• Using reflection within an optical element eliminates the inefficiencies and variations inherent in bending optical fiber or sealing epoxy to a metallic mirror surface .
• the optical element is formed from an epoxy which provides filling and sealing of the light emitting window such that no additional light losses occur by passing light through separate lenses or interfaces .
• the required angle of impingement of the light on the internal surface to create the 90 degree turn is 45 degrees, more than the substantially 40 degree or 40.4 degrees minimum of the embodiment described herein, based on Snell's law and the epoxy used, that will cause light rays to reflect internally.
• the limiting value is calculated from the ratio of the index of refraction properties of the optical element and air.
• the invention is directed to an apparatus, for use with, for example, a surgical drill, in the repair of bones using an intramedullary nail insertable into a patient's bone, the intramedullary nail having a hollow body portion and a distal transverse hole, the apparatus comprising a tube like device for insertion into the intramedullary nail, the device having an opening through which light from a light source emitting electromagnetic non-ionizing radiation in the infrared or visible portions of the electromagnetic spectrum is emitted, an optical conduit, such as a bundle of optical fibers, or a somewhat flexible light pipe, in the tube for conducting light from a light source to the proximity of the opening; and an optical element providing total internal reflection, which may be a light transparent reflector, generally having a surface which crosses the light path at an angle, appearing as wedge shaped in cross section, disposed in the tube, and which is sized, shaped and positioned to receive light from the optical conduit and to internally reflect the light so that the light exits the tube through the tube opening.
• the end of the optical conduit, or the ends of the fibers can be embedded in the optical element .
• the optical element can comprise a hardened resin.
• the end of the optical conduit, or the ends of the fibers, are embedded in the optical element before the resin is hardened, and the resin is solidified around the ends of the optical conduit or fibers .
• the optical element may comprise a hardened epoxy, wherein the epoxy fills the opening and seals to the tube .
• the reflective surface of the optical element can be made to act as a beam shaping mirror by designing it as a convex or concave shape, or by adding facets.
• the external surface of the optical element serves as a lens . In this embodiment it is a convex cylindrical lens focusing the light beam as it leaves the tube opening.
• the resin, and in particular the two part epoxy resin, from which the optical element is formed should have high spectral transmission, should be medically acceptable or compatible, should be able to withstand the temperature range required for steam sterilization, and have good adhesion to steel and glass .
• the reflector may be a molded or machined element of a polymer or a glass, and the optical conduit may extend from an external surface of the optical element .
• An end cap may seal an end of the tube closest to the opening, to preserve the cleanliness and integrity of an air pocket behind the optical element's reflective surface.
• the invention is also directed to a method for producing an apparatus for use with, for example, a surgical drill in the repair of bones using an intramedullary nail insertable into a patient's bone, comprising providing a tube like device for insertion into the intramedullary nail, the device having an opening through which light from a light source emitting electromagnetic non-ionizing radiation in the infrared or visible portions of the electromagnetic spectrum is emitted, placing an optical conduit, such as a bundle of optical fibers, or a somewhat flexible light pipe, in the tube for conducting light from a light source to the proximity of the opening; and disposing in the tube an optical element providing total internal reflection, which may be a light transparent reflector, generally having a surface which crosses the light path at an angle, appearing as wedge shaped in cross section, and sized, shaped and positioned to receive light from the optical fibers and to internally reflect the light so that the light exits the tube through the tube opening.
• an optical conduit such as a bundle of optical fibers, or a somewhat flexible light pipe
• the end of the optical conduit can be embedded in the optical element .
• the optical element can be formed of a hardened resin .
• the end of the optical conduit or optical fibers are embedded in the optical element before the resin is hardened, and the resin is solidified around the ends of the optical conduit or fibers .
• the optical element can be formed of a hardened epoxy, wherein the epoxy fills the opening and seals to the tube.
• the reflective surface of the optical element may be formed in place in the tube by placing a removable plug in an end of the tube closest to the opening, the plug having an end with a shape complimentary to the shape of an internally reflective surface of the optical element; placing a resin which can harden in place in the tube between the end of the plug and ends of the optical fibers; and hardening the resin in place.
• the method may further comprise removing the plug from the tube; and placing an end cap on the tube so as to seal the end of the tube closest to the opening, to preserve the cleanliness and integrity of an air pocket behind the optical element's reflective surface.
• the method can further comprise capturing ends of the optical fibers in a ferrule to form an optical fiber subassembly; and embedding ends of the optical fibers of the subassembly in the optical element before the epoxy hardens .
• the ends of said optical fibers can be captured in the ferrule by applying an epoxy resin in the spaces between the optical fibers and between the optical fibers and the ferrule; and applying heat treatment to harden and relieve stresses in the epoxy.
• Fig. 1 is a plan view of an apparatus in accordance with the invention mounted.
• Fig. 2 is an end view of the apparatus of Fig. 1.
• Fig. 3 is an enlarged cross-sectional view of a portion of the apparatus of Fig. 1.
• FIG. 1 there is shown a plan view of an apparatus 10, incorporating features of the present invention.
• the present invention will be described with reference to the single embodiment shown in the drawings, it should be understood that the present invention can be embodied in many alternate forms of embodiments.
• any suitable size, shape or type of elements or materials could be used.
• apparatus 10 of Fig. 1 useful for intramedullary transillumination, is described generally in the abovementioned United States Published Patent Application 20070270864 of James P. Gurtowski, and will not be discussed in detail herein, but instead is incorporated herein by reference for all purposes.
• apparatus 10 has a light coupling 12 to which a commercial fiber optic light source, of a type well known in the art, and used in medical applications, may be coupled to provide light to a conduit for light, such as a bundle of optical fibers which run along the length of a tubular housing or tube 14, of apparatus 10, tube 14 being generally formed of thin walled, medically compatible stainless steel .
• the internal reflection design in a current embodiment utilizes a fiber subassembly 16 that is terminated with a stainless steel ferrule 18 at either end into which the fibers of the subassembly 16 have been inserted, epoxied, and polished flush.
• the epoxy is EPO-
• TEK 353ND available from Epoxy Technology Inc. of Billerica, MA, USA. It is first cured using, for example a heat gun, as the temperature of initial cure is not believed to be critical. However, these subassemblies 16 are then cured or annealed for 5 minutes at 250 degrees
• the high temperature cure reduces internal stresses within the stainless steel ferrule containing the glass fibers and raises the glass transition temperature of the epoxy.
• the optical fiber subassembly 16 is assembled into the tubular housing or tube 14 through its light collecting end such that the emitting end points straight down the axis of the housing away from the source connected to apparatus 10 by connector 12 after a temporary plug (not shown) including a surface for directing and shaping light at roughly 45 degrees is inserted into the emitting end of the housing.
• the temporary plug is positioned so that the angled surface faces the fiber assembly and also the light emitting aperture 20 in the side of the tubular housing or tube 14.
• This temporary plug may be made of a variety of materials, including Teflon® or Delrin® (or other material to which the epoxy does not strongly adhere, preferably such as a high density polyethylene (HDPE)) in order to facilitate removal later. It may also be gasketted with an O-ring, or other compliant material such as a tape, to contain the liquid epoxy.
• HDPE high density polyethylene
• a light transparent and medically acceptable epoxy such as EPO-TEK 302-3M, available from Epoxy Technology Inc. of Billerica, MA, USA, is applied to the device through the aperture 20 in the side of the tubular housing 10.
• the epoxy fills the cavity in the tubular housing or tube 14 formed by fiber subassembly 16 and the temporary plug, bonding to and constraining the emitting end of the optical conduit (the optical fibers in the ferrule 18, in this embodiment of the invention) and taking the shape of the bottom of the temporary plug.
• the epoxy hardens for 24 hours at room temperature forming the optical element, the fiber assembly at the light input end of the device is glued using the same 302-3M epoxy, for example.
• the fiber assembly is compressed slightly during this gluing operation to prevent lengthwise tensile forces from being imposed on the fiber assembly during the intense heat of steam sterilization.
• the plug is removed and the assembled unit is heat treated for 1 hour at 125 degrees C.
• the temporary plug is then replaced with a mechanical end cap 24 to protect the reflecting surface and the required air gap behind it, and also to finish the housing assembly.
• the optical element or reflector 22 may also be modified in shape or through its reflective surface to distribute the light in other patterns, including a version which distributes light at up to 360 degrees around the tubular housing.
• the temporary plug may be shaped with a generally conical end, and may be inserted with the tip pointing toward the fiber subassembly 16.
• the temporary plug may have a size and shape similar to end cap 24, but will extend close to the tube opening and will have a further extending sloping surface which is complementary to, and thus defines, the internally reflecting surface of optical element 22, when the resin of element 22 is cast into tube 14.
• the optical element or reflector 22 may also be designed in as a molded or machined polymer or glass component and the fiber subassembly 16 may be modified to be integral with the optical element or reflector 22 or can be bonded to it in some manner as to insure maximum light transmission.
• a light pipe may also be used as a light conductive element.
• such light pipe should be flexible enough to bend with the thin walled stainless steel of tube 14 sufficiently to allow it to be inserted into and removed from an intramedullary nail, which is often bent slightly in accordance with how a patient's bone is formed.

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• Health & Medical Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Surgery (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Molecular Biology (AREA)
• General Health & Medical Sciences (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• Neurology (AREA)
• Animal Behavior & Ethology (AREA)
• Engineering & Computer Science (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Pathology (AREA)
• Radiology & Medical Imaging (AREA)
• Dentistry (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Surgical Instruments (AREA)

Applications Claiming Priority (2)

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• 2009
  • 2009-04-21 EP EP09733847.9A patent/EP2285302A4/de not_active Withdrawn
  • 2009-04-21 WO PCT/US2009/041248 patent/WO2009131999A2/en not_active Ceased
  • 2009-04-21 JP JP2011506393A patent/JP2011518022A/ja active Pending
• 2010
  • 2010-10-21 IL IL208885A patent/IL208885A0/en unknown

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