Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/42—Joints for wrists or ankles; for hands, e.g. fingers; for feet, e.g. toes
  • A61F2/4202—Joints for wrists or ankles; for hands, e.g. fingers; for feet, e.g. toes for ankles
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
  • A61F2002/30316—The prosthesis having different structural features at different locations within the same prosthesis; Connections between prosthetic parts; Special structural features of bone or joint prostheses not otherwise provided for
  • A61F2002/30535—Special structural features of bone or joint prostheses not otherwise provided for
  • A61F2002/30579—Special structural features of bone or joint prostheses not otherwise provided for with mechanically expandable devices, e.g. fixation devices
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/30—Joints
  • A61F2/42—Joints for wrists or ankles; for hands, e.g. fingers; for feet, e.g. toes
  • A61F2/4202—Joints for wrists or ankles; for hands, e.g. fingers; for feet, e.g. toes for ankles
  • A61F2002/4223—Implants for correcting a flat foot

Definitions

• the present invention generally regards the devices used in medicine in surgical operations, and more particularly those devices which remain inside the body of the patient after the operation, in order to treat specific undesired characteristics, in the present case an incorrect position of the bones of the foot.
• the present invention regards an improvement of the so-called endo-sinus-tarsal screws, which are implanted in the body of the patient (child or even adult) in order to treat the deformity of the so-called "flat foot”.
• tarsal sinus which is substantially cylindrical-shaped and located between two bones, i.e. between the calcaneum and the astralagus.
• various (titanium) metal screws are provided, with different caliber/diameter (e.g.: from 9 to 14 mm) and a certain subset thereof is used on the basis of the size of the enlargement to be carried out in said channel.
• the enlargement of the tarsal sinus in fact produces a lifting of the astragalus which consequently cancels the flat shape of the arch of the foot.
• the object of the present invention is to eliminate the problems of the prior art.
• the endo-sinus-tarsal screw of the invention is globally substantially cylindrical- shaped, though conical at least in the proximal part.
• Such configuration of the screw of the invention allows it to be immediately adapted to the shape - also substantially cylindrical but slightly conical - of the tarsal sinus, so as to avoid an excessive insertion thereof.
• the radiation doses deriving from the use of the luminance amplifier will be considerably lower, since the (final) position of the endo-sinus-tarsal screw shall be verified only at the end of the operation.
• the screw of the present invention has an expansion function. It must be inserted only once in the tarsal sinus, and the expansion - similar to a stop to be inserted in a wall - will occur gradually by allowing the surgeon to visually observe the variation of the valgus angle of the hindfoot.
• the screw of the invention externally (or laterally) has a flexible sleeve that is uniformly expanded, it is impossible that the expansion will occur in just some zones, as it unfortunately used to occur in the case of several types of expansion screws of the prior type, with expansion tabs separate from each other.
• the screw of the invention is substantially expanded in a uniform manner even with respect to the axial direction, i.e. both in the proximal part and in the distal part, due to the fact that a second component thereof - which is movable with respect to a first component and couplable to a screwer - pushes, by means of a tapered portion (3 c) thereof, the flexible sleeve against the proximal conical part (2a) of the first component, causing a lateral expansion of the flexible sleeve (6).
• a preferred embodiment of the invention provides for a kind of stop (7) of the sleeve.
• the stop is preferably formed by an annular projection (7) provided on the conical part (2a) of the first component (2).
• Such stop (7) besides improving the expansion of the sleeve, also prevents, in this preferred embodiment of the invention, a possible unthreading of the flexible sleeve from the central metallic body of the screw (formed by the two components that are movable with respect to each other).
• the two metallic components normally made of titanium alloy
• the distal cylindrical part of the screw has structures (6c) (ribs or the like) for facilitating the adherence of the expandable sleeve to the wall of the channel (tarsal sinus).
• structures (6c) ribs or the like
• the conical proximal part (6a) of the sleeve there will be elements for anchoring to the wall of the tarsal sinus.
• anchoring elements are constituted by one or more oblique tabs (8), directed towards the proximal end of the endo-sinus-tarsal screw.
• the obliqueness of the tabs ensures that the more the sleeve tends to exit, the more the tabs tend to penetrate in the tissues, thus ensuring the reliability of the screw (which is not "spit" out of the channel).
• the first component is threaded on the second component.
• the second component (3) By acting with a screwer on the second component (3), the latter is axially moved with respect to the first component (2), by pushing on the expandable sleeve.
• the use of other mechanical means can also be assumed, in order to obtain the same relative axial movement between the two components (2, 3). Nevertheless, this would probably complicate the screw production process.
• the two components (2, 3) are monolithic (single cast pieces) and are preferably metallic.
• the flexible sleeve is preferably obtained by molding preferably plastic material in a single piece.
• the present invention also comprises a set, or instruments, constituted by the screwer, the endo-sinus-tarsal screw described above, and by a support that is coupled to the endo-sinus- tarsal screw and serves to introduce and laterally support the stem with hexagonal tip of the screwer which is engaged in a hexagonal hole of the second component of the screw.
• Said support, part of the instruments provided to the surgeon obviously serves to avoid that the whole screw rotates around its own axis (it is driven in rotation) when the screwer is used, i.e. to ensure the rotation of only the second component that pushes against the front distal part of the expandable sleeve.
• Fig. la shows a vertical axial section of the endo-sinus-tarsal screw of the present invention, according to a first embodiment
• Fig. lb shows a perspective view in partial section of the endo-sinus-tarsal screw of the present invention, according to the first embodiment
• Fig. 1 c shows the relative top plan view
• Fig. 2a shows a vertical axial section of the endo-sinus-tarsal screw of the present invention, for the second embodiment
• Fig. 2b shows a partial section perspective view of the endo-sinus-tarsal screw of the present invention, for the second embodiment
• Fig. 2c shows the top plan view of the endo-sinus-tarsal screw of the second embodiment of the invention
• Fig. 3 shows two instruments used for the correction operation according to the present invention, also part of the object of the invention
• Fig. 4 shows the two instruments of Fig. 3 inserted inside each other and in the endo-sinus- tarsal screw of the invention. Description of the preferred embodiments of the invention
• the endo-sinus-tarsal screw 1 comprises a first component 2 made of rigid, resistant, biocompatible and preferably metallic material, normally made of titanium alloy, and a second component 3, also made of rigid, resistant and biocompatible material and preferably made of titanium alloy.
• the first component 2 comprises a proximal conical part 2a and a distal substantially cylindrical part 2b which forms various steps (different diameters).
• the first component 2 has an axial through hole, indicated in its entirety with the reference number 4.
• the through hole 4 constitutes a hexagonal hole 4a, the intermediate part of the through hole 4 is indicated with 4b and it is cylindrical, whereas the "lower" part (in Fig. la) of the through hole 4 is threaded and it is indicated with 4c. It is observed that the holes 4a, 4b, 4c have progressively decreasing diameters, forming respective steps.
• the second component 3 has a form similar to the shank 3 a of a nail (constant diameter) whose head 3b (lower part 3b in Fig. la) has a tapered lateral surface 3c and a convex frontal surface 3d.
• the component 3 has a hole 5, comprising a cylindrical hole 5a and a hexagonal hole 5b with a smaller diameter with respect to the cylindrical hole 5a.
• the hexagonal hole 5b in one embodiment of the invention ends on the lower part with the through hole 3e which centrally traverses the entire component 3, until it reaches the front convex surface 3d.
• the through hole 3e serves for inserting and guiding the endo- sinus-tarsal screw along a previously positioned common rigid guide wire.
• This endo-sinus- tarsal screw in this embodiment of the invention, is screwed with a cannulated screwdriver 10 in a manner so as to receive at its interior the rigid guide wire which will be inserted inside the through hole 3e upon the positioning of said screw. "On the upper part" (still with reference to Fig. la), the shank 3a is externally threaded in order to be screwed in the threaded hole 4c of the first component 2.
• a sleeve 6 is fit on the two components 2, 3; such sleeve is made of material having a certain flexibility that allows the same to be expanded within certain predetermined limits.
• the sleeve 6 can be made of high-density polyethylene (HDPE) for an improved distribution of the load forces that act on the sleeve 6 (see below).
• the sleeve 6 has an overall cylindrical shape with "upper” conical part 6a and intermediate cylindrical part 6b equipped "on the lower part” with ribs 6c or other structures that allow a grip/anchorage of the sleeve 6 on the tissues of the walls of the tarsal sinus.
• the sleeve 6 In its "lower" conical-converging part 6d, opposite its conical part 6a, the sleeve 6 has a flared frontal hole 6e for receiving and housing the head 3b of the second component 3 substantially shaped as a nail. It is observed that the tapered lateral surface 3c is in contact or comes into contact, i.e. interacts, with the flared frontal hole 6e of the flexible sleeve 6. This is of fundamental importance, as will be seen, for causing the expansion of the flexible sleeve 6.
• annular projection 7 for the abutment of the sleeve 6) which enlarges the "upper" diameter of the conical part 2a of the first metallic component 2 (e.g. made of titanium alloy), such annular projection 7 preferably being made integral with the conical part 2a itself when casting the first component 2.
• the elements 7 and 8 provide further very significant advantages with respect to the first embodiment, as will be clear from the description of the functioning of the screw (the prime indicates the screw of the second embodiment, while the screw of the first embodiment was indicated by the reference number 1).
• a special metallic support tool (Fig. 3, reference 9), provided with grip handle 9a and tubular part 9b for coupling and insertion, integral with the same grip handle 9a, the surgeon draws the endo-sinus-tarsal screw 1 (or 1 ') from a loader and inserts it into the tarsal sinus after the operation preparatory steps (anesthesia, incision etc.).
• the surgeon grasps the tool or instrument 9 by the handle 9a and introduces the end with hexagonal tip 9b (tube for coupling and insertion of the screw, Fig. 3) in the hexagonal hole 4a of the first component 2.
• the tapered lateral surface 3c of the second component 3 pushes against the wall of the flared frontal hole 6e or better yet (as in the drawing) against the innermost circumference of the hole 6e itself.
• the flexible sleeve 6 is expanded, being anchored to the internal wall of the tissues of the tarsal sinus and pressing against such wall. The anchorage occurs due to the circular ribs 6c. Once the desired expansion diameter has been attained, the instruments 9 and 10 are extracted.
• the expansion diameter of the flexible sleeve 6 is clearly correlated to the number of complete turns of the (possibly cannulated) screwer 10.
• a mechanical revolution counter device 10b could be provided (with rigid disc connected to the screwer 10 and cooperating with a reference needle 9c on the tool 9) or the like (encoder: magnetic, with Hall effect, optical or potentiometric) adapted to determine the absolute rotation angle of the screwer 10, possibly displaying it on a display together with the relative value of the temporary diameter of the sleeve.
• Other mechanical systems could serve for the same purpose as revolution counter devices according to the present invention.
• the arrangement of the reference needle 9c and the rigid disc 10b could naturally also be reversed.
• the preferred and less expensive method simply consists of obtaining (by means of incision, coloring etc.) a graduated scale of values on the stem of the screwer 10, to be compared with the reference point fixed on the instrument 9 at the entrance of the tubular part 9b.
• the endo-sinus-tarsal screw of the present invention has the particular characteristic that with only one device, it is possible to correct the deformity of the foot and immediately control the correction, either visually (graduated scale) or by means of a suitable revolution counter (encoder, or the like).
• Another particular characteristic is that the screw reproduces the substantially cylindrical but more particularly conical form of the tarsal sinus, so that by being uniformly expanded (both distally and proximally) it is able to be anchored to the walls of the tarsal sinus, ensuring an optimal grip, thus preventing its exit and consequent loss of the correction.
• the tab (or tabs) 8 is/are fixed in the wall of the tarsal sinus in proximal position; in addition, it is clear that the proximal expansion of the flexible sleeve 6 (and hence the anchorage to the wall of the channel) is optimized by the presence of the annular projection 7 on the head 2a of the screw 1 ', when the flexible sleeve 6 abuts against the annular projection 7 itself. It is thus evincible that the elements 7 (annular projection) and 8 (tab or tabs) of the second embodiment constitute improvements with respect to the first embodiment.
• the endo-sinus-tarsal screw according to the present invention could be defined "double expansion screw" since it ensures - unlike the prior art - a uniform distal as well as proximal expansion.
• the screw of the invention eliminates the entire drawback of an expansion screw type of the prior art which only expanded at the intermediate part.
• the screw of the invention is adapted to raise the astralagus on the calcaneum (correcting the foot deformity) as if it were a jack for vehicles, whereas the expansion as such is similar to that obtained by inserting a stop in a wall.
• a possible further development of the present invention consists of equipping the screwer with a dynamometric electronic instrument, i.e. a torque transducer, with setting of the final torque and continuous detection of the instantaneous torque (twisting moment) acting on the conical head 2a of the endo-sinus-tarsal screw.
• a dynamometric electronic instrument i.e. a torque transducer

Landscapes

• Health & Medical Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Cardiology (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Transplantation (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Vascular Medicine (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Surgical Instruments (AREA)
• Orthopedics, Nursing, And Contraception (AREA)
• Portable Nailing Machines And Staplers (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=45814606

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (4)

• 2012
  • 2012-01-12 IT IT000009A patent/ITRM20120009A1/it unknown
• 2013
  • 2013-01-11 WO PCT/IT2013/000012 patent/WO2013105123A1/en not_active Ceased

Patent Citations (4)

Also Published As

Similar Documents

Legal Events