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
  • A61F2/14—Eye parts, e.g. lenses or corneal implants; Artificial eyes
• • 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
  • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting in contact-lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
  • A61F9/007—Methods or devices for eye surgery
  • A61F9/00772—Apparatus for restoration of tear ducts

Definitions

• the present invention relates to a medical device that has its main application in corrective tear-duct surgery.
• the improvements provided by the device greatly help to overcome the numerous disadvantages of previous approaches in this field.
• tear fluid that is "lacrimal” fluid
• lachrymal glands each being located in a lateral and superior relation to the respective eye.
• Upper lacrimal ducts feed the fluid from each gland to a respective conjunctival sac, in which the relevant eyeball is partially encased.
• the lacrimal fluid subsequently washes the sclera and other conjunctival components of the eye, as well as its cornea.
• the resultant permanent closure can require a corrective surgical procedure known as a dacryocystorhinostomy (DCR).
• DCR dacryocystorhinostomy
• the sole blockage occurs in, for example, the nasolacrimal duct, the latter can be removed, and the remaining lacrimal sac cavity can then be joined directly with the mucosa of the nasal fossa. This is typically achieved by removing tissue, including the intervening segment of nasal bone and periosteum, so that the drainage of tear liquid into the nose can be more or less restored.
• the nasal bone heals around the lower end portion of the inserted replacement tube, the latter is gradually rejected from the bone and flesh of the patient. And secondly, the patient's flesh also tends to heal over the external end of the replacement tube at the inner-canthus (1), which therefore requires appropriate surgical reopening from time to time.
• the replacement tube utilised in tear-duct surgery has been a small tube constructed of PyrexTM glass, stiff plastic or some other relatively rigid material.
• PyrexTM-type glass that has been preferred, since this can neither be destroyed, nor corroded or otherwise affected by a patient's bodily fluids.
• double-flanged Jones-type tubes have also been previously made available. These have two opposing flanges at either end of a hollow shank, with the aim of attempting to prevent their rejection.
• these tubes tend not to be particularly effective either since, in practice, they have at least the following extra disadvantages:
• This leading flange is furthermore positioned at a relatively sub-optimal site along the shank, being right at its internal tip and, therefore, after insertion the orifice at this tip is prone to blockage by the normal growth of the nasal mucosa that closely surrounds it.
• FR- A-2, 813, 522 discloses the use of a tubular lacrimal drain (11, 12) having one or more parts, one of which is an internal fixing unit. This allows anchoring of the drain (11,12), typically by providing a screw-threaded attachment means (10, 12a).
• CN-A-I 5 650, 824 also provides an artificial tear duct, in this case being in the form of a spiral spring-like structure, typically used as a temporary stent to allow scar tissue to become stable before the spring is softened and thereafter pulled out as an unravelled metal wire.
• US-B-5, 062, 831 discloses the use of a solid tubing (16), having no lumen, for temporarily removing excess lacrimal fluid by capillary action.
• a conventional DCR is performed, by removing adjacent bone so that the remaining sac communicates with the internal nasal meatus (7).
• a catheter (13), with enlarged portions (15) at either end of an elongate shank portion (14), is used simply as a temporary stent to prevent scarring over of the newly opened hole between the sac and the nose.
• the present invention aims to provide an improved device for correcting tear-duct obstructions and, in particular, for the correction of canalicular obstructions.
• the latter have previously tended to be even less successfully treated than blockages of other tear- duct system parts.
• the present invention provides a tear-duct drain comprising: (a) a hollow rigid tube, being elongate and having a first flange at one extremity; and (b) a flexible, resilient and collapsible second flange, being bonded to said tube at a predetermined distance away from, and so providing a leading edge at, the opposite extremity of said tube.
• the device of the present invention has the advantages that it can be more accurately placed in situ and with greater ease than previous devices, as well as being able to be left more stably in situ afterwards. This befits the relatively more permanent correction that it can provide, if such permanency is required.
• Potentially permanent devices of this type also need to be easily removeable, at least temporarily, so that they can be cleansed along with the patient's consequently vacated tissue passageway. This helps to avoid, for example, microbial contamination, so that tissue damage resulting from inflammation is less likely to occur. If left unchecked, however, such damage would tend to increase the likelihood of rejection of the device from the patient.
• the elongated tube of each of these improved devices may be made of any suitably inert material that promotes a high level of biocompatibility with patient tissue, as well as the preferred ease of cleaning the device as a whole upon its temporary withdrawal.
• the tube of the present device has a first enlarged external portion at one end that is designed to act as an anchor at the corner of the patient's eye, it also has a collapsible second flange that is preferably positioned towards the opposite end of the tube. Because of its resilience and, typically, relatively large diameter, this second flange tends to prevent the device from slipping.
• the tube may be indented on either side of the site of bonding to provide recesses (in the tube's surface) that can accommodate the second flange when flexed.
• Figure 1 schematically illustrates the functional anatomy of a normal and healthy tear- duct system
• Figures 2-5 depict known devices attempting, as described above, to correct various obstructions of unhealthy tear-duct passages;
• Figures 6A-D show an improved device according to one embodiment of the present invention
• Figures 7A-D illustrate an improved device according to a further embodiment of the present invention.
• Figures 8A-B show an enlarged view of one embodiment of the device of the present invention, in which the site of bonding of the second flange to the tube is schematically highlighted;
• Figures 9A-E depict some variations of possible shapes for the second flange of the device of the present invention.
• the tear-duct drain (21) shown in Figure 6A has a first flange (28) at the external (that is, inner-canthal) opening (23) of its tube (24).
• a second flange (25) is also provided and is positioned close to - but not at - the internal (that is, nasal) opening (26) of the leading edge (27) of the tube (24).
• the tube (24) and first flange (28) are composed of a rigid material, for example a glass or a plastics material. Glass is generally a preferred material, since it has excellent capillary characteristics and is very biocompatible.
• the relative dimensions, and relative resilience, of the second flange (25) are predetermined to allow the tube (24), when in situ, to be stable to any potentially destabilising forces that might otherwise cause either its movement inwards into the nose or outwards towards the eye. Patients are therefore provided with a significant safety benefit to their eyes. Complete loss of the device (21) is also reduced.
• the relative resilience of the second flange (25) can be defined in terms of the degree of the relative shear forces involved. That is, for example, the maximum shear force that the flange (25) can withstand before it collapses; and, the respective minimum that it can overcome before it bounces back into shape.
• the flexibility of the second flange (25) also ensures that it can collapse in both directions. That is, both; (i) towards the external end (28) of the tube (24) [a “first flush position”]; and, (i ⁇ ) towards the leading edge (27) of the tube (24) [a "second flush position”].
• the position adopted depends upon the direction in which the tube is being urged by the surgeon.
• the second flange (25) can thus adopt the first flush position during the tube's insertion (that is, in direction I, as shown in Figure 6B).
• the resilience of the second flange (25) enables it to spring open.
• This springing open can if necessary be facilitated by the surgeon, for example by applying a degree of manual pressure against the elasticity of the tissue area surrounding the nasal (inner) orifice of the lumen of the passageway, so as to aid release of folded flange into nasal meatus (7).
• the collapsible flange is typically bonded to the inert material of the tube (24) by a suitable adhesive.
• a suitable adhesive for example, any glue that can bond potential collapsible flange (25) material, such as silicone, to the material of the tube (24), for example glass, can be used.
• the chosen glue should also preferably be able to withstand high temperatures for autoclaving, as well as being generally tissue biocompatible.
• the shape of the flange (25) at its site of bonding to the tube may be splayed to allow greater strength.
• the splaying (34, 35, 36) may advantageously allow the flange (25) to have a greater surface area that can be adhered to the tube (24).
• the bonded second flange (25) can be made of any appropriately flexible material that retains its memory after deformation, such as, for example a silicone or a rubber, or indeed alternatively any suitable plastics material.
• the exact shape of the second flange (25) can be chosen to suit the needs of each specific patient and so it need not necessarily be circular (as shown in Figure 6A) in cross-section.
• Figures 9A-E further non-limiting examples of the many different types that can be appropriately utilised are shown in Figures 9A-E.
• the second flange (25) comprises a plurality of arms radiating from the central lumen (26), it is preferable that an odd number of arms are incorporated. This allows the arms to fold into a more compact arrangement as the flange (25) collapses, thus minimising the cross-sectional diameter of the device (21) as it is inserted into place or temporally withdrawn for cleaning.
• the outer circumferential profile of the second flange (25) is preferably as uniformly smooth as possible, for example any arms should preferably have rounded extremities.
• the second flange (25) is pre-bonded at a predetermined set distance (22) from the internal end (27) of the glass tube (24), and so the clinician need not actually bond the second flange (25) to the tube (24) at any stage.
• the glass tubes are also typically manufactured to predetermined lengths, so that, the length required to match each patient's anatomy can be chosen by the surgeon before the corrective procedure is commenced.
• the improvements provided by the device (21) of the present invention allow it to be inserted, if necessary, as a relatively permanent system, often as an independent bypass of a patient's natural tear-duct system.
• the chosen parameters of the device (21) and particularly those of its second flange (25), greatly enhance its ability to efficiently provide this permanent type of treatment, by avoiding counterproductive complications (such as inflammation of the nearby tissues, and so forth) that, as mentioned above, might otherwise arise.
• the present device (21) is particularly suited to correction of canalicular obstructions.
• the device (21) can easily be placed into the correct in situ position (as shown in Figure 6C). By making use of the slight elasticity of the intervening tissue, this can be achieved by inserting it inwardly into the passage (see Figure 6B) until the leading edge (27) of the tube is sufficiently inside the nasal meatus (7). This allows the internal second flange (25) to have already flexibly opened out due to its inherent resilience. The device (21) can then be withdrawn slightly until the opened second flange (25) abuts the nasal mucosa surrounding the internal orifice of the bypass passage.
• the positioning of the internal second flange (25), and thus the in situ placement of the device (21) as a whole, can therefore be accurately controlled by the clinician.
• the bonding of the second flange (25) to the tube (24) at a predetermined distance from the internal end (27) of the tube ensures that a section (22) of the tube is proud of the second flange (25). Being proud, its obstruction (for example by the formation of scar tissue from the nasal mucosa) is much less likely when it is in situ, so helping to promote a more continuous drainage of the excess lacrimal fluid.
• Devices according to the present invention may, of course, differ in their absolute dimensions from case to case, with these being specifically chosen so as to maximise the above-described advantages for each individual patient.
• the outer diameter of the first, rigid flange (28) might be chosen to be between about 3 to 4mm, whilst that of the tube (24) would then suitably be about 2-2.5mm.
• the diameter of the second flange (25) would typically be of the order of 7.5mm or less, and preferably about 5mm.
• Its thickness (29) would consequently be of the order of lmm or less, and the tube's proud section (22) would also generally have a chosen length of about lmm.
• any recesses (31) as mentioned above - for example see Figure 7 - can also be varied to accommodate the associated dimensions chosen for the second flange (25).
• portion of the tube (24) adjacent to the edges of the flange (25) can be raised slightly to provide support.
• the device does not depend upon gravity, by having the relatively large weight flanges that are used in some known devices.
• the device also does not rely upon its tube having to be cut to size or glued during its insertion, or its flanges being cut off to allow its withdrawal.

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• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Animal Behavior & Ethology (AREA)
• Veterinary Medicine (AREA)
• Public Health (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Vascular Medicine (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Plastic & Reconstructive Surgery (AREA)
• Surgery (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Cardiology (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Transplantation (AREA)
• External Artificial Organs (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Materials For Medical Uses (AREA)
• Prostheses (AREA)
• Infusion, Injection, And Reservoir Apparatuses (AREA)
• Surgical Instruments (AREA)

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Publications (1)

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• 2006
  • 2006-09-29 GB GB0619305A patent/GB2442205B/en active Active
• 2007
  • 2007-04-02 US US11/695,300 patent/US7758534B2/en active Active
  • 2007-09-11 EP EP07804206A patent/EP2073769B1/en active Active
  • 2007-09-11 WO PCT/GB2007/003408 patent/WO2008037951A1/en not_active Ceased
  • 2007-09-11 AT AT07804206T patent/ATE487448T1/de not_active IP Right Cessation
  • 2007-09-11 DE DE602007010497T patent/DE602007010497D1/de active Active
  • 2007-09-11 JP JP2009529750A patent/JP5197608B2/ja not_active Expired - Fee Related

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