Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
  • 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, setting implements or the like
  • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
  • A61B17/72—Intramedullary pins, nails or other devices
  • A61B17/7208—Flexible pins, e.g. ENDER pins

Definitions

• the invention relates to an intramedullary spindle, and in particular an intramedullary spindle for the elastic and stable support of long bones for osteosynthesis.
• an elastic intramedullary spindle consisting of a rod of biocompatible material, of section adapted to the bone to be treated.
• osteosynthesis of long bones is limited by the fragility of the bone structure, in particular the cortical bone of the elderly. Osteoporosis facilitates perforation of the bone by the intramedullary spindle, leading to compaction of the fracture site and secondary displacement of the fractured bone despite the presence of the reducing pin (s).
• an intramedullary pin usable both in childhood trauma and in the elderly, where elastic and stable support is sought in order to promote osteosynthesis, reducing the risk of perforation bone epiphysis or growth cartilage, while effectively preventing secondary compaction of the bone.
• An object of the invention is therefore to provide an intramedullary pin, implantable in the bone with a view to
• the rod is folded back on itself, so as to form at least one branch ending in a loop at one head end of the spindle.
• the rod is folded back on itself, substantially at 180 °, approximately in the middle of its length, so as to form two branches substantially of the same length, connected by the head portion in a loop.
• the mean plane of the loop makes an angle relative to the longitudinal axis of the pin, in order to facilitate the intramedullary insertion of the pin.
• FIG. 1 schematically represents an intramedullary pin according to the invention
• FIG. 2 schematically represents another embodiment of the pin of FIG. 1,
• Figure 3 schematically shows a variant of the pin of Figure 2
• FIG. 4 schematically represents in longitudinal section, a long bone presenting a multiple fracture, provided with an intramedullary pin according to the invention
• FIG. 5 is a view, similar to FIG. 4, of a bone presenting an oblique fracture
• FIG. 6 is a view, similar to FIG. 5, of a bone presenting a multiple fracture, provided with an intramedullary pin of the known technique.
• the pin 1 according to the invention consists of a rod 2 folded back to form a loop 3 at one end, which is the head end, to be inserted substantially up to the cortical wall, at the epiphysis of the fractured bone.
• the terminal part of loop 3 is presented set back from the maximum width "d 'of the loop 3. Although this is not shown in the drawing, the loop 3 can be closed, in the form of a ring.
• the pin 1 is formed of a rod folded substantially in the middle, to form two branches 2, 2 ′ connected at the head by a loop 3.
• the variant of FIG. 3 differs from the embodiment of FIG. 2 in that the head part comprising the loop 3 makes an angle ⁇ with respect to the rest of the longitudinal extent of the spindle.
• the purpose of this variant is simply to facilitate the initial insertion of the head of the spindle into the bone, as will be seen below.
• the branches 2, 2 ′ are shown to be substantially rectilinear, with the exception of the elbow at the angle ⁇ in FIG. 3, and parallel, but it is obvious that this does not constitute a parameter of l 'invention.
• the spacing between the branches may not be constant, and they may if necessary be braided together if this has an advantage, for example for reasons of mechanical strength, or convenience of insertion, but at the expense of elasticity.
• the surface defined by the branches 2, 2 ′ and the loop 3 will generally be a left surface, taking into account the deformability of the rod constituting the spindle.
• the deflection angle ⁇ marked in the drawing therefore represents the angle of the mean plane of the head portion, with respect to the mean plane of the branches 2, 2 ', rather than the actual angle of curvature of the branches 2, 2'.
• the aim of this angle is to facilitate the insertion of the head of the spindle into the medullary canal, and its value is therefore not critical for the invention.
• Figures 4 and 5 show a pin of the invention in position in a long bone
• Figure 6 is a view similar to Figure 4, but with a straight pin of the known technique, represented as having perforated the cortical wall.
• FIG. 4 to 6 there is shown a pin 1, 1 'inserted in a long bone 10 shown in schematic section, with two epiphyses 11, 12 connected by the diaphysis 13, and a medullary canal 14.
• the surgeon folds the end of the foot 16 into the opening 15, to block this end relative to the bone.
• the angle ⁇ of the head part of FIG. 3 facilitates the initial crossing of the elbow between the opening 15 and the medullary canal 14, during the passage of the head 3; for the remainder of the operation, the spindle is flexible enough to be flexed elastically as said elbow passes.
• FIGS. 4 to 6 also indicate by arrows "A" the direction of the forces exerted by the muscles and tendons on a long bone, forces which go in the direction of a longitudinal compression of the bone.
• the loop 3 of the pin of the invention provides a greater contact surface between the pin and the bone, and therefore reduces the pressure on the bone, and the risk of perforation.
• This effect is further reinforced by the fact that, unlike the steep end of the known spindle, which tends by nature to have a perforating effect (force in the axis of the rod), the loop 3 of the spindle the invention with its curved contact surface has no perforating effect.
• the two branches (2, 2 ') have substantially the same length, which means that they must both reach the opening 15 for insertion into the 'bone, to allow the need to remove the pin.
• the embodiment of the broach with two branches, according to FIGS. 2 and 3, is preferred compared to the embodiment with a branch of FIG. 1. Indeed, the surgeon is frequently required to place several pins in the same bone , and the loops of crooked pins according to FIG. 1 are more likely to become entangled, making possible extraction difficult. Also, with equal cross section, the size of two pins in the stock according to FIG. 1 is greater than that of a pin with two branches according to FIGS. 2 and 3, and the placement will therefore be more difficult. Finally, the two branches 2, 2 ′ of a spindle according to FIGS. 2 and 3 will each be thinner, and will therefore have greater elasticity than the single branch 2 of the embodiment of FIG. 1, with equal total section .
• an effective pin has been provided for the elastic consolidation of long bones, while avoiding or reducing the risk of perforation, in a simple and economical manner, since it suffices to fold back on itself, preferably substantially at mid-length, a conventional pin rod.
• the spinal cord of the invention is useful in long bones, including small bones, such as those of the hand.
• the diameter of the loop 3 is not in itself a parameter of the invention, and it can in particular be as large as the fractured bone allows.
• the effectiveness of the solution of the invention seems to result from the combination of an increase in the contact surface between the end of the pin and the bone epiphysis, which reduces the maximum local pressure on the bone tissue, and an increase in the elasticity of the spindle, resulting from its curvature.

Landscapes

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

Applications Claiming Priority (1)

Publications (1)

Family

ID=3888738

Family Applications (1)

Country Status (2)

Families Citing this family (4)

Family Cites Families (4)

• 1995
  • 1995-06-30 WO PCT/BE1995/000062 patent/WO1997001990A1/fr not_active Application Discontinuation
  • 1995-06-30 EP EP95924116A patent/EP0835080A1/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events