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
  • 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 prosthetic lacrimal sac apparatus.
• the dacryocystitis or inflammation of the lacrimal sac, is a very common condition due to an inflammatory process of the medial nasal meatus or to the blockage of the tear ducts, with stagnation of secretions and infection thereof.
• the chronic dacryocystitis presents with an excessive lacrimation and oozing of mucous secretions and can be complicated by a catarrhal conjunctivitis or by a keratitis.
• the chronic dacryocystitis usually due to an obstruction of the tear ducts (stenosis), requires a surgical treatment (dacryocystorhinostomy) to remove the lacrimal sac or to restore the drainage into the nasal cavity.
• Object of the present invention is to overcome the drawbacks of the prior art, by providing a lacrimal sac prosthesis that is extremely efficient and effective in reestablishing the drainage into the nasal cavity and at the same time is able to ensure a long life with the maximum efficiency.
• Another object of the present invention is to provide such a prosthesis that is versatile and simple to implant in the nasal sac.
• Yet another object of the present invention is to provide such prosthesis that is cheap and simple to make.
• the lacrimal sac prosthesis comprises: - a central pump defining a pumping chamber adapted to be placed in the lacrimal sac,
• proximal tube connected to the pump and adapted to be inserted into a canaliculus of the lacrimal apparatus so that its end communicates with the lacrimal punctum of the eye
• a distal tube connected to the pump and adapted to be inserted into the naso-lacrimal duct so that its end communicates with the nasal cavity.
• Figure 1 is a side view of the lacrimal sac prosthesis according to the invention
• Figure 2 is a top plan view of the prosthesis of Figure 1 ;
• Figure 3 is an axial sectional view of the pump of the prosthesis of Figure 1;
• Figures 3A and 3B are two enlargements of the parts enclosed in circles A and B of
• Figure 3 showing an outlet valve and an inlet valve, respectively;
• Figure 4 is a diagrammatic view showing the anatomy of the lacrimal apparatus;
• Figures 5-10 are diagrammatic views like Figure 4, showing the various stages of the surgical procedure for the implantation of the prosthesis according to the invention.
• the lacrimal sac prosthesis designated as a whole with the reference numeral 1, is described with the aid of Figures 1-3.
• the prosthesis 1 comprises a pump 2, substantially ogival in shape, which forms a chamber 20 with a substantially elliptical section.
• the size and the shape of the pump 2 have been designed to allow it to be inserted and positioned inside the nasal sac.
• the pump 2 has a major axis of about 15 mm, a minor axis of about 4 mm and a thickness of 0.5 mm.
• a proximal tube 3 and a distal tube 4 are connected to the pump 2.
• the distal tube 4 is coaxial with the major axis of the pump 2; the proximal tube 3, on the other hand, has an axis inclined by an angle ⁇ of between 90° and 150°, preferably 120°, with respect to the axis of the distal tube 4.
• the proximal tube 3 is slightly smaller than the distal tube 4. In fact the proximal tube 3 is destined to be inserted into the canaliculi of the lacrimal sac, whereas the distal tube 4 is destined to be inserted into the tear duct.
• the proximal tube 3 is about 60 mm long with an outer diameter of 1 mm and an inner diameter of 0.75 mm.
• the distal tube 4, on the other hand, is about 77 mm long with an outer diameter of 1.5 mm and an inner diameter of 1 mm.
• a guide wire 5 with a length of 80 mm and a diameter of 0.3-0.5 mm is fixed to the distal end of the distal tube 4.
• the guide wire 5 has a rigid tip 50 of greater thickness that is round or tapered to facilitate the entry thereof into a cavity of the patient, as will be described hereunder.
• the dimensions of the various elements of the prosthesis are entirely indicative and can vary with a tolerance of about 50% according to the patient's anatomical sizes.
• the pump 2 comprises an inlet duct 21 communicating with the proximal tube 3 and an outlet duct 22 communicating with the distal tube 4.
• a one-way valve 6 is provided that allows the fluid to pass only from the proximal tube 3 towards the inlet duct 21 of the pump, in the direction of the arrow I, and does not allow the liquid to return from the pump chamber 20 to the proximal tube 3.
• a one-way valve 7 is provided that allows the fluid to pass only from the pump chamber 20 towards the distal duct 4 of the pump, in the direction of the arrow O, and does not allow liquid to return from the distal tube 4 to the pump chamber 20.
• the pump 2, the proximal tube 3 and distal tube 4 are made of a plastic material that is biocompatible and at the same time is sufficiently flexible and deformable to adapt to the implantation site and to allow a pumping effect through compression of the body of the pump 2.
• the pump 2 and the tubes 3 and 4 are preferably made of silicone, but they may also be made of polysulphone or polyethylene.
• the guide wire 5 is preferably made of stainless steel, but it can also be made of Nitinol.
• the ends of the tubes 3 and 4 are vulcanized into the body of the pump 2 at the inlet and outlet ducts 21, 22 and the valves 6 and 7 are integrated into the tubes 3 and 4.
• the pump 2 and the two tubes 3 and 4 may be coated with a biocompatible material, such as, for example, turbostratic pyrolytic carbon.
• Figure 4 shows diagrammatically the anatomy of the lacrimal apparatus.
• the lacrimal apparatus comprises a superior canaliculus 10 and an inferior canaliculus 1 1 which lead from the lacrimal punctum 15 of the eye to the lacrimal sac 12.
• the canaliculi 10 and 11 are about 10-12 mm in length and are disposed in a substantially inverted V-shaped configuration, forming an angle of about 50° with each other.
• the lacrimal sac 12 is situated below the medial palpebral ligament 13 and is substantially cylindrical in shape with a length of 12-15 mm and a diameter of 3-5 mm. Beneath the lacrimal sac 12 there is the naso-lacrimal duct 14 which is frusto-conical in shape with a length of about 15-18 mm. The end 16 of the lacrimal duct 14 communicates with the cavity 17.
• the patient Before the surgical procedure, the patient is given locoregional anaesthesia by terminal infiltration with Marcaine and Carbocaine and by a possible anterior packing of the nostril with Novesine-soaked gauze.
• a vertical skin incision 30 about 2 cm long is made, in the region of the lacrimal sac, at the root of the nose, at a distance of about 2 cm from the medial canthus.
• the incision 30 is made with blunt dissection of the muscle structures below the internal palpebral ligament 13, so as to obtain a good exposure of the palpebral ligament 13 and to be able to visualise the lacrimal sac 12.
• a stiffened guide wire 40 with a rigid tip 41, is inserted into the lacrimal punctum 15 of the eye in the direction of the arrow F and is passed through the superior canaliculus 10 or the inferior canaliculus 1 1 , until the rigid tip 41 of the guide wire is seen to emerge into the cavity of the lacrimal sac 12.
• the rigid tip 41 of the guide wire 40 is recovered from the lacrimal sac 12 and passed through the incisions 31 and 30, pulling it in the direction of the arrow R, until it exits the surgical site.
• the rigid tip 41 of the guide wire is then cut and the guide wire 40 is left in situ.
• a Bowman probe 50 is inserted through the surgical openings 30 and 31 and is oriented so as to probe the lacrimal duct 14. The correctness of this procedure can be verified by rhinoscopy or by direct flushing of the lacrimal duct 14, inviting the patient to swallow.
• curettage with a Tartuferi probe can be performed to facilitate the introduction of the prosthesis 1 according to the invention.
• the tip 50 of the guide wire 5 of the prosthesis 1 is inserted into the surgical openings 30 and 31, intubating the naso-lacrimal duct 14 with the distal tube 4, until the guide wire 5 is seen to exit the nasal cavity 17.
• the body of the prosthesis 1 is pushed in the direction of the arrow F and the guide wire 5 is pulled in the direction of the arrow R.
• the end 42 of the guide wire 40 that passes through the canaliculus 10 and exits from the surgical opening 30 is tied to the free end of the proximal tube 3, as far as said end of the proximal tube of the prosthesis protrudes from the surgical opening 30.
• the guide wire 5 of the prosthesis is pulled again, until the end of the proximal tube 3 is at the level of the superior canaliculus 10.
• the other guide wire 40 is pulled in the direction of the arrow W.
• the guide wire 40 pulls with it the proximal tube 3 which is introduced retrogradely into the superior canaliculus 10, thus also obtaining the intubation of the upper canaliculus 10, as shown in Figure 10.
• the correct placement of the prosthesis 1 can be confirmed by flushing the lacrimal duct 14 again.
• the Bowman probe 50 can be removed from the surgical site.
• the protruding ends of the distal tube 4 and of the proximal tube 3, which are tied to the respective guide wires 5 and 40, are cut.
• a silicone or collagen punctum plug that is a tapered, funnel shaped element, per se known in ophthalmology, which serves to favour the lacrimal drainage into the proximal tube 3, is placed a the end of the proximal tube 3.
• the body of the pump 2 is perfectly housed within the lacrimal sac 12 and sutures which might cause scar formation are not needed to fix it.
• the pumping action of the prosthesis 1 can take place by a simple batting of the eyelids.
• a compression of the pump 2 obtained by means of the palpebral ligament 13, causes the emptying of the pump chamber 20 and the drainage of the liquid through the distal outlet duct 4 which passes through the lacrimal duct 14.
• the pump 2 After the compression, the pump 2 returns to its initial configuration, sucking the liquid through the proximal inlet duct 3 and filling the chamber 20 again.
• the above described surgical technique serves to restore a normal drainage path, instead of creating a new one, respecting the anatomy of the bony structures and of the soft tissues.
• the lacrimal pump mechanism is left practically intact, by restoring the angular ligament.
• the natural defences of the lacrimal sac with respect to the nasal cavity are also maintained.

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• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Biomedical Technology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Surgery (AREA)
• Engineering & Computer Science (AREA)
• Plastic & Reconstructive Surgery (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)
• Prostheses (AREA)

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Citations (5)

• 2007
  • 2007-07-25 IT ITMI20071496 patent/ITMI20071496A1/it unknown
• 2008
  • 2008-07-07 WO PCT/EP2008/005518 patent/WO2009012879A1/en active Application Filing

Patent Citations (5)

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