CA1258355A - Retinal tack and method for implanting same - Google Patents
Retinal tack and method for implanting sameInfo
- Publication number
- CA1258355A CA1258355A CA000506653A CA506653A CA1258355A CA 1258355 A CA1258355 A CA 1258355A CA 000506653 A CA000506653 A CA 000506653A CA 506653 A CA506653 A CA 506653A CA 1258355 A CA1258355 A CA 1258355A
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- Prior art keywords
- tack
- retina
- retinal
- choroid
- tne
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
The retinal tack includes a generally conical, sharply pointed forward end portion for piercing through the retina, choroid, and sclera, an elongated, generally cylindrical retaining portion having a longitudinal dimension approximating the thickness of a patient's retina, choroid, and sclera and including one or more peripheral grooves for receiving sclera tissue displaced during insertion of the forward end portion, and an enlarged head having a radially extending flange portion for engaging the retina in the area of the opening formed in the retina. The tack is carried in the tip of a tubular probe selectively connected in fluid communication with sources of negative and positive pressures and the head includes a seat portion which sealingly engages a complementary seat in the probe tip when a negative pressure is applied to the probe. The probe is inserted into the vitreous cavity through an opening in the eyeball and the tack is manually pushed through the retina, choroid, and sclera in the vicinity of the retinal tack until the head engages the retina and the retina is moved against the choroid. After a small positive pressure is introduced into the probe, it is moved away from the tack and withdrawn from the vitreous cavity.
The retinal tack includes a generally conical, sharply pointed forward end portion for piercing through the retina, choroid, and sclera, an elongated, generally cylindrical retaining portion having a longitudinal dimension approximating the thickness of a patient's retina, choroid, and sclera and including one or more peripheral grooves for receiving sclera tissue displaced during insertion of the forward end portion, and an enlarged head having a radially extending flange portion for engaging the retina in the area of the opening formed in the retina. The tack is carried in the tip of a tubular probe selectively connected in fluid communication with sources of negative and positive pressures and the head includes a seat portion which sealingly engages a complementary seat in the probe tip when a negative pressure is applied to the probe. The probe is inserted into the vitreous cavity through an opening in the eyeball and the tack is manually pushed through the retina, choroid, and sclera in the vicinity of the retinal tack until the head engages the retina and the retina is moved against the choroid. After a small positive pressure is introduced into the probe, it is moved away from the tack and withdrawn from the vitreous cavity.
Description
35~
RETINAL TACK AND M~THOD FOR IMPLANTIMG SAME
BACKGROUND OF THE INVENTION
-This invention relates to ophthalmological corrective surgery and, more particularly, to devices and methods for reattaching a detached retina.
Various techniques have been proposed for reattaching a detached retina to the choroid.
one approach involves injecting a silicone oil or a ~as into the vitreous cavity of the eye~ Some question remains with respect to the safety of intravitreous silicone oil and gas injection requires the patient to remain prone.
Another approach involves the use of one or more sutures. This approach can be hazardous and, therefore, has not been widely accepted.
~ further approach involves the use of a retinal tack which is held with a mechanical device, such as intraocular forceps, and inserted through the retina into the choroid and sclera.
American Journal of O~hthalmology, vol 9S, No. 2, p.
260 (February 1983) describes a plastic tack including a relatively short barb, a tapered section behind the barb, and a relatively long and massive head including slots to facilitate grasping by the forceps. ThiS retinal tack has been found to have a tendency to ~pop out" of the sclera within a relatively short time after surgery and, therefore, is not being widely used. Retinal tacks including several barbs have been proposed. While retention is improved somewhat, such tacks are difficult to remove in the event of a retinal tear.
~5l5 35~
RETINAL TACK AND M~THOD FOR IMPLANTIMG SAME
BACKGROUND OF THE INVENTION
-This invention relates to ophthalmological corrective surgery and, more particularly, to devices and methods for reattaching a detached retina.
Various techniques have been proposed for reattaching a detached retina to the choroid.
one approach involves injecting a silicone oil or a ~as into the vitreous cavity of the eye~ Some question remains with respect to the safety of intravitreous silicone oil and gas injection requires the patient to remain prone.
Another approach involves the use of one or more sutures. This approach can be hazardous and, therefore, has not been widely accepted.
~ further approach involves the use of a retinal tack which is held with a mechanical device, such as intraocular forceps, and inserted through the retina into the choroid and sclera.
American Journal of O~hthalmology, vol 9S, No. 2, p.
260 (February 1983) describes a plastic tack including a relatively short barb, a tapered section behind the barb, and a relatively long and massive head including slots to facilitate grasping by the forceps. ThiS retinal tack has been found to have a tendency to ~pop out" of the sclera within a relatively short time after surgery and, therefore, is not being widely used. Retinal tacks including several barbs have been proposed. While retention is improved somewhat, such tacks are difficult to remove in the event of a retinal tear.
~5l5 35~
-2- 70557-32 SUMMARY OF THE INVENTION
One of the objects of the invention is to provide a retinal -tack which has improved retention characteristics and can be conveniently inserted through the retina, choroid, and sclera.
The invention provides a retinal tack for securing a human patient's detached retina to the choroid comprising:
a pointed forward end portion for piercing through the patient's retina, choroid, and sclera;
an elongated retaining portion extending rearwardly from said forward end portion and having a longitudinal dimension approximating the thickness of the patient's retina, choroid, and sclera, said retaining portion including one or more circumferen-tially-extending grooves for receiving sclera tissue displaced by said forward end portion during insertion there-through; and an enlarged head extending rearwardly from said re-taining portion and having a radially outwardly extending flange portion for engaging the retina inthe area surrounding the opening formed by said forward end portion. The retinal tack described herein can be removed with minimal trauma to the sclera and choroid in the event of a retinal tear.
Other aspects and advantages of the invention will become apparent to those skilled in the art upon reviewing the following detailed description, the drawing and the appended claims.
In one embodiment, the forward end portion is generally conical, the retaining portion has a generally cylindrical surface, each groove has 35~
cadially outwardly extending forward and rear side walls, and the groove forward side wall forms a shacp corner witn tne outer surface witn tne tetaining por~ion. The reac side wall of each groove preferably i3 outwardly inclined in a rearward direction to facilitate witndrawal of the tack in tne event of a retinal tear or the like.
The retinal ~ack is rel~asably carried on tne tip of a tubular probe Qelectively coQnected in fluid co~nunication wi~n sources of su~atmospheric and -~uperatmosperic pressure and the nead includes a seat portion wnich is received by and sealingly engages a complementary seat in tne probe tip.
In one embodiment, the head includes a collar extending rearwardly fcoln the flange, a reduced stu~ portion which fits inside tne probe tip, and a cnamfered portion wnicn connects the ~tub pottion witn a collac and sealingly engages a seat in the pcobe tip.
The retinal tack is celeasably held in tne probe tip by a negative pressure in tne interior passage of tne probe. Tne probe i5 inserted into the vitreous cavity tbrougn an opening in tne eyeball and tne tack is ma~ually inserted through the cetina, cnocoid, and sclera in tne vlcinity of tne retinal teac until tne nead engage~ the retina ~nd tne retina is moved against the c~oroid. A smaLl positive pcessure then is intcoduced into tne interior passage of tne probe to permit tne pcobe to be moved away 30 from the tack and withdrawn from the vitreous cavity tnrougn the eyeball opening.
~5~35~
BRIE:F DE:SCRIPTION OF THE DRAWING
Fig. 1 is a perspective, partially schematic view of a system for implanting a retinal tack of the invention.
Fig. 2 is a cross-sectional view of a patient's eye with the implantation instrument probe shown in position after implantation o~ a retinal tack.
Fig. 3 is an enlarged sectional view taken generally along-line 3-3 in Fig. 2.
Fig. 4 is an enlarged view of an alternate arrangement for the retinal tack and the implantation instrument probe.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 illustrates a system 10 for implanting a retinal tack of the invention. The system 10 has a conventional pump assembly 11 including a vacuum pump 12 and an air pump 14 (both illustrated schematically) driven by an electric motor (not shown) and suitably housed in a cabinet 16. The vacuum pump 12 and the air pump 14 are connected in fluid communication with an outlet fitting 18. The system 10 also has an implantation instrument 20 including a cylindrical housing 22 having an inte,rior passage which is connected in fluid communication with the outlet fitting 18 via a flexible hose or conduit 24~
The implantation instrument 20 includes a needle-like, tubular probe 26 which resembles a needle for a hypodermic syringe and ucually has an outside diameter of about 0.040 inch or less. The probe 22 has an interior passage 28 (Fig. 3)
One of the objects of the invention is to provide a retinal -tack which has improved retention characteristics and can be conveniently inserted through the retina, choroid, and sclera.
The invention provides a retinal tack for securing a human patient's detached retina to the choroid comprising:
a pointed forward end portion for piercing through the patient's retina, choroid, and sclera;
an elongated retaining portion extending rearwardly from said forward end portion and having a longitudinal dimension approximating the thickness of the patient's retina, choroid, and sclera, said retaining portion including one or more circumferen-tially-extending grooves for receiving sclera tissue displaced by said forward end portion during insertion there-through; and an enlarged head extending rearwardly from said re-taining portion and having a radially outwardly extending flange portion for engaging the retina inthe area surrounding the opening formed by said forward end portion. The retinal tack described herein can be removed with minimal trauma to the sclera and choroid in the event of a retinal tear.
Other aspects and advantages of the invention will become apparent to those skilled in the art upon reviewing the following detailed description, the drawing and the appended claims.
In one embodiment, the forward end portion is generally conical, the retaining portion has a generally cylindrical surface, each groove has 35~
cadially outwardly extending forward and rear side walls, and the groove forward side wall forms a shacp corner witn tne outer surface witn tne tetaining por~ion. The reac side wall of each groove preferably i3 outwardly inclined in a rearward direction to facilitate witndrawal of the tack in tne event of a retinal tear or the like.
The retinal ~ack is rel~asably carried on tne tip of a tubular probe Qelectively coQnected in fluid co~nunication wi~n sources of su~atmospheric and -~uperatmosperic pressure and the nead includes a seat portion wnich is received by and sealingly engages a complementary seat in tne probe tip.
In one embodiment, the head includes a collar extending rearwardly fcoln the flange, a reduced stu~ portion which fits inside tne probe tip, and a cnamfered portion wnicn connects the ~tub pottion witn a collac and sealingly engages a seat in the pcobe tip.
The retinal tack is celeasably held in tne probe tip by a negative pressure in tne interior passage of tne probe. Tne probe i5 inserted into the vitreous cavity tbrougn an opening in tne eyeball and tne tack is ma~ually inserted through the cetina, cnocoid, and sclera in tne vlcinity of tne retinal teac until tne nead engage~ the retina ~nd tne retina is moved against the c~oroid. A smaLl positive pcessure then is intcoduced into tne interior passage of tne probe to permit tne pcobe to be moved away 30 from the tack and withdrawn from the vitreous cavity tnrougn the eyeball opening.
~5~35~
BRIE:F DE:SCRIPTION OF THE DRAWING
Fig. 1 is a perspective, partially schematic view of a system for implanting a retinal tack of the invention.
Fig. 2 is a cross-sectional view of a patient's eye with the implantation instrument probe shown in position after implantation o~ a retinal tack.
Fig. 3 is an enlarged sectional view taken generally along-line 3-3 in Fig. 2.
Fig. 4 is an enlarged view of an alternate arrangement for the retinal tack and the implantation instrument probe.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 illustrates a system 10 for implanting a retinal tack of the invention. The system 10 has a conventional pump assembly 11 including a vacuum pump 12 and an air pump 14 (both illustrated schematically) driven by an electric motor (not shown) and suitably housed in a cabinet 16. The vacuum pump 12 and the air pump 14 are connected in fluid communication with an outlet fitting 18. The system 10 also has an implantation instrument 20 including a cylindrical housing 22 having an inte,rior passage which is connected in fluid communication with the outlet fitting 18 via a flexible hose or conduit 24~
The implantation instrument 20 includes a needle-like, tubular probe 26 which resembles a needle for a hypodermic syringe and ucually has an outside diameter of about 0.040 inch or less. The probe 22 has an interior passage 28 (Fig. 3)
3~;
connected in fluid communication with the interior passage of the housing 22 and, thus, with the outlet fitting 18 of the pump assembly 11.
The interior passage 28 of the pro~e 26 is selec~ively connected in 1uid sommunication with the vacuum pump 12 and ~he air pump 14 by an electrically-operated control valve 30 (illus~rated schematically~. The control valve 30 is moved between "vacuum" and "pressure" positions by operation of a suitable hand- or foot-operated switch ~not shown). The outlet pressure of the vacuum pump 12 and the air pump 14 is i~dicated respectively by pressure gauges 32 and 34 on the front of the cabinet 18.
The vacuum pump 12 is adjusted to provide a negative or subatmospheric pressure in the - order of 19 in. Hg at the tip 35 of the probe 26.
The air pump 14 is adjusted to provide a small positive or superatmospheric pressure in the order of 20 mm Hg at the tip 35 of the probe 26. Referring to Figs. 2 and 3, a retinal tack 36, including a piercing portion and a retaining portion described in more detail below, is carried by the probe tip 35 and is releasably held therein by a negative pressure in the order of 19 in Hg created in the interior passage 28 of the probe 26 by moving the control valve 28 to the "vacuum" position~
Referring to Fig. 2, a 20-gauge wound is made in the eyeball 40 at an appropriate location and a standard cannula 42 i~ inserted therein and sutured in place to serve as a port. While observing the interior of the eyeball through a ophthalmosope or surgical microscope, a probe having a blunt end (not shown) is introduced into the vitreous cavity 44 through the cannula 42 and manipulated to lay the detached retina 46 back into place against the choroid 48. This probe is withdrawn from the vitreous cavi~y and the implantation instrument probe 26 carrying a retinal tack 36, with the control valve 23 in the "vacuum" position, is introduced into the vitreous cavity 44 through the cannula 42.
The retinal tack 36 is positioned against the retina 46 at a location close to the tear and the piercing portion of the retinal tack 36 is manually pushed through the re~ina 46, choroid 48 and the sclera 50 until the retina 46 is moved against the choroid 48. The control valve 30 is then moved to the "pressure" position to create a positive pressure in the order of 20 mm ~ in the interior passage 28 of the probe 26. This small positive pressure assists in releasing the probe 26 from the retinal tack 36 and prevents the intraocular pressure in the vitreous cavity 44 from forcing vitreous fluids out through the probe 26. However, this pressure is low enough to prevent the retinal tack 36 from being driven further into the choroid 48 and/or the sclera 50.
Depending on the e~tent of the retinal tear, two or more retinal tacks 36 may be required to hold the detached retina 46 in place.
~ig. 3 illustrates a preferred embodiment of the retinal tack 36, The tack 36 include~ a piercing portion 52 in the form of a sharply pointed forward end, an elongated retaining protion 54 extending rearwardly from the ~orward end 52 and an enlarged head 56 extending rearwardly from the retaining portion 54.
8 ~5 The forward end portion 52 preferably i5 generally concial and nas a point which is as -~narp a~ po~3ible in ordec to minimize teacing of tne retina 46, cnocoid 48 and scle~a 50 during insertion therethroug~.
The retaining portion 54 has a longitudinal dimension approximating tne tnickness of the retina 46, choroid 48 and sclera 50 and includes one ot more peripnerial groove fo~ receiving ~lera tissue displaced during insertion of the ~oeward end portion 52 tnerethrougn. Tn~ retaining portion 54 preferably has a generally cylindrical outer sur~ace 60. Tne outermo~t diameter of tne retaining portion 54 pteferably is su~stantially constant along the lengtn tnereof and i3 equal to or greater ~nan the maximum outer diame~er of the forward end por~ion 52.
The sclera 50 tends to conform to tne exterior of the retaining portion 54 and portions of tne tis~ue extending into the grooves 58 assist in ~ .. . .. .. .
retaininy the tack 36 in place. Each groove 58 has radially extending front and rear side wall~ 62 and 64. To further enhance retention, the forward ~ide wall 62 preferably extend3 generally perpendicularly to the longitudinal axis 66 of tne tack 36 and forms a sharp corner 68 with tbe outer surface 60. Tne included angle of tne corner 68 between tne outer ~urface 60 and th@ forward ~ide wall 62 prefera~ly is about 90 or le~s. It has been found that rounded corner~ or cotners of an obtu~e angle generally provide poorer eetention. It also ba~ been found tnat providing the retaining pottion 54 witn a generally cylindrical outer ~urf w e provides better retention, pro~ably becau~e tne sclera ti~sue applie~
a more uniform pr~ure on a larger ~uface area.
3~
To facilitate removal o~ tne tack 36 after implantation iQ the event of a retinal tear or tne like, tne rear wall 64 of eacn groove 58 pceferably is outwardly inclined in a rearward direction.
The head 56 include~ a radially outwardly extending flange 70 whicn engages tne retina 46 in tne area ~urcounding the opening formed ~y tne piercing portion 52. T~e head 56 preferably nas a circular cros~ 3ection and tne flange 70 prefera~ly extendc generally perpendicularly to the longitudinal axis 66 of tne tack 36~ The head 56 also include3 an annular seat portion adap~ed to be received by and sealingly engage a complementary seat on tne probe tip 35.
In the embodiment illustrated in Fig.
3, the nead 56 has a circular collar 72 extending rearwardly from tne flange 70, a red~ced, generally cylindrical stub poction 74 extending ~earwardly ~rom the collar 72 and an annular, chamfered ~eat portion 76 connecting the stu~ po~tion 74 witn tne collar 72. The seat portion 76 i~ tapered ~adialLy inwardly in a rearward diraction.
Tne stub portion 74 fit~ snugly inside the interior passage 28 of the probe 26 and tne seat portion 76 3ealingly engage-~ a complementary annular ~eat 78 in ~ne pro~e tip 35 w~e~ a n~gative pressure exi~ts in tne intetior pa3~age 28,. Surface contact ~etwe~n tne outer end 80 of the pro~e tip 35 and the collar 72 and between the wall 82 of the probe interior pa~sage 26 ~nd the ~tub portion 74 provides lateral ~upport li~e., resi~tance to torque applied on the forward end of the tack 36~ again~t breaking tne ~eal between the tack ~ea~ portion 76 and the 5~
probe seat 78 wnen tne tack 36 is ~eing implanted.
Breakage of thi seal could cause the tack 36 to fall away from the pto~e 26 and drop into tne vitreous cavity 44.
Tne ceduced diameter of tne stub poction 74 facilitates gtasping with a foceign body foreceps in the event the tack 36 is accidentally dropped into tne vitreous cavity 44.
The ou~er dimension of tne head 56 is l9-guage (about 0.040 inch) or less ~o tnat it can fit through a standard cannula for a 20-gauge wound.
Tne overall lengtn of tne tack 36 will vary and depends primarily on tne thickness of the retina, cnoroid, and sclera of a particular patient. Tnat lS is, tne retaining portion 54 of tacks u~ed in adult patients is lon~er than that for tack~ used in c~ildren. As a guide, tne overall length of the tack 36 can be in tne ocder of about 0.060 to 0.110 incn.
The retaining portion 54 can have ~ length of about 0. 01 to 0 . 02 and an ou~er dimension about 0. 020 incn. Tne piercing Rection 52 can nave a lengtn of about 0.025 to 0.045 inch. The overall lengtn of the head 56 can be about 0. 02 to 0 . 03 incn and tne lengtn of tne stu~ portion 74 can be a~out 0.015 to 0. 02 inch.
Fig. 4 illustrates an alternate embodiment of tne retinal tac~ designed for use in children and otner patients having thinner cetina, choroid, and sclera In tni~ embodiment, the length of the piercing section 52a of tne retinal tack 36a i~ sligntly less, the length of the retaining portion 54a is shorter (but still approxim~tely tne thickne o the retina, cnoroid, and ~clera), tne retaining portion 54a includes a single groove 58 ~nd the head nas a different 3eating arCang~meQt.
More specifically, the entice outer sueface 84 of tne head 56 is tapered radially inwardly in a rearward direction and serves ag a seat which ~ealinyly engages a complementary seat 86 in tne pro~e tip 36a when a negative pressure exists in the p~o~e interioc passage 28a. In tnis embodiment, lateral ~upport for tne tac~ 56a depends entirely on 3urface contact between the tapered surface 84 of tne n~ad 56a and tne probe seat 86. Tnese two surfaces are configured to provide a tight taper-to-tapec fit.
Tne angle of ~aper for t~e head surface 84 and the probe seat preferably i5 about 10 to 20.
Witn an angle of taper ~reater than about 20, applica~ion of celatively small torques on tne forward end of tne tack 36a will ~reak tne ~eal ~etw~en tne head surface 84 and tne probe seat 86.
On tne otner hand, witn an angle of taper les~ tnan about 10, tne wall3 of the pcobe tip 36a become quite fragile and make it more difficult to pick up tacks.
It ShOUld be under~tood that both tne head arrangements illu~trated in Figs. 3 and 4 can be used on retinal t~cks having a retaining section including one or a plucality of grooves.
~5 The retinal tack can be fabricated from various celatively hard, inert, non-blood corrosive materials suit~ble for u~e in ~ numan body, iw luding commercially pure titanium and plastlc materials such as polyacetal3 and polyetnylmethacrylate. At the pre~ent time, commercially pure, Gr~d~ 4 titaminum is prefered because it can be macnined to provide tne de ired configurational featuEes, particarly a ~narp point on the piercing portion, the sharp co~ner ~etween the front side walls of tne grooves and tne jjl5 3~
;11-outer sucface of tne retaining portion and tne tapered seat on tne head.
From tne foregoing description, one skilled in the art can easily ~scectain the essential cnaracteristics of tne invention and, without departing from the spirit and scope tnereof, make various cnanges and modifications to adapt it to various usages.
connected in fluid communication with the interior passage of the housing 22 and, thus, with the outlet fitting 18 of the pump assembly 11.
The interior passage 28 of the pro~e 26 is selec~ively connected in 1uid sommunication with the vacuum pump 12 and ~he air pump 14 by an electrically-operated control valve 30 (illus~rated schematically~. The control valve 30 is moved between "vacuum" and "pressure" positions by operation of a suitable hand- or foot-operated switch ~not shown). The outlet pressure of the vacuum pump 12 and the air pump 14 is i~dicated respectively by pressure gauges 32 and 34 on the front of the cabinet 18.
The vacuum pump 12 is adjusted to provide a negative or subatmospheric pressure in the - order of 19 in. Hg at the tip 35 of the probe 26.
The air pump 14 is adjusted to provide a small positive or superatmospheric pressure in the order of 20 mm Hg at the tip 35 of the probe 26. Referring to Figs. 2 and 3, a retinal tack 36, including a piercing portion and a retaining portion described in more detail below, is carried by the probe tip 35 and is releasably held therein by a negative pressure in the order of 19 in Hg created in the interior passage 28 of the probe 26 by moving the control valve 28 to the "vacuum" position~
Referring to Fig. 2, a 20-gauge wound is made in the eyeball 40 at an appropriate location and a standard cannula 42 i~ inserted therein and sutured in place to serve as a port. While observing the interior of the eyeball through a ophthalmosope or surgical microscope, a probe having a blunt end (not shown) is introduced into the vitreous cavity 44 through the cannula 42 and manipulated to lay the detached retina 46 back into place against the choroid 48. This probe is withdrawn from the vitreous cavi~y and the implantation instrument probe 26 carrying a retinal tack 36, with the control valve 23 in the "vacuum" position, is introduced into the vitreous cavity 44 through the cannula 42.
The retinal tack 36 is positioned against the retina 46 at a location close to the tear and the piercing portion of the retinal tack 36 is manually pushed through the re~ina 46, choroid 48 and the sclera 50 until the retina 46 is moved against the choroid 48. The control valve 30 is then moved to the "pressure" position to create a positive pressure in the order of 20 mm ~ in the interior passage 28 of the probe 26. This small positive pressure assists in releasing the probe 26 from the retinal tack 36 and prevents the intraocular pressure in the vitreous cavity 44 from forcing vitreous fluids out through the probe 26. However, this pressure is low enough to prevent the retinal tack 36 from being driven further into the choroid 48 and/or the sclera 50.
Depending on the e~tent of the retinal tear, two or more retinal tacks 36 may be required to hold the detached retina 46 in place.
~ig. 3 illustrates a preferred embodiment of the retinal tack 36, The tack 36 include~ a piercing portion 52 in the form of a sharply pointed forward end, an elongated retaining protion 54 extending rearwardly from the ~orward end 52 and an enlarged head 56 extending rearwardly from the retaining portion 54.
8 ~5 The forward end portion 52 preferably i5 generally concial and nas a point which is as -~narp a~ po~3ible in ordec to minimize teacing of tne retina 46, cnocoid 48 and scle~a 50 during insertion therethroug~.
The retaining portion 54 has a longitudinal dimension approximating tne tnickness of the retina 46, choroid 48 and sclera 50 and includes one ot more peripnerial groove fo~ receiving ~lera tissue displaced during insertion of the ~oeward end portion 52 tnerethrougn. Tn~ retaining portion 54 preferably has a generally cylindrical outer sur~ace 60. Tne outermo~t diameter of tne retaining portion 54 pteferably is su~stantially constant along the lengtn tnereof and i3 equal to or greater ~nan the maximum outer diame~er of the forward end por~ion 52.
The sclera 50 tends to conform to tne exterior of the retaining portion 54 and portions of tne tis~ue extending into the grooves 58 assist in ~ .. . .. .. .
retaininy the tack 36 in place. Each groove 58 has radially extending front and rear side wall~ 62 and 64. To further enhance retention, the forward ~ide wall 62 preferably extend3 generally perpendicularly to the longitudinal axis 66 of tne tack 36 and forms a sharp corner 68 with tbe outer surface 60. Tne included angle of tne corner 68 between tne outer ~urface 60 and th@ forward ~ide wall 62 prefera~ly is about 90 or le~s. It has been found that rounded corner~ or cotners of an obtu~e angle generally provide poorer eetention. It also ba~ been found tnat providing the retaining pottion 54 witn a generally cylindrical outer ~urf w e provides better retention, pro~ably becau~e tne sclera ti~sue applie~
a more uniform pr~ure on a larger ~uface area.
3~
To facilitate removal o~ tne tack 36 after implantation iQ the event of a retinal tear or tne like, tne rear wall 64 of eacn groove 58 pceferably is outwardly inclined in a rearward direction.
The head 56 include~ a radially outwardly extending flange 70 whicn engages tne retina 46 in tne area ~urcounding the opening formed ~y tne piercing portion 52. T~e head 56 preferably nas a circular cros~ 3ection and tne flange 70 prefera~ly extendc generally perpendicularly to the longitudinal axis 66 of tne tack 36~ The head 56 also include3 an annular seat portion adap~ed to be received by and sealingly engage a complementary seat on tne probe tip 35.
In the embodiment illustrated in Fig.
3, the nead 56 has a circular collar 72 extending rearwardly from tne flange 70, a red~ced, generally cylindrical stub poction 74 extending ~earwardly ~rom the collar 72 and an annular, chamfered ~eat portion 76 connecting the stu~ po~tion 74 witn tne collar 72. The seat portion 76 i~ tapered ~adialLy inwardly in a rearward diraction.
Tne stub portion 74 fit~ snugly inside the interior passage 28 of the probe 26 and tne seat portion 76 3ealingly engage-~ a complementary annular ~eat 78 in ~ne pro~e tip 35 w~e~ a n~gative pressure exi~ts in tne intetior pa3~age 28,. Surface contact ~etwe~n tne outer end 80 of the pro~e tip 35 and the collar 72 and between the wall 82 of the probe interior pa~sage 26 ~nd the ~tub portion 74 provides lateral ~upport li~e., resi~tance to torque applied on the forward end of the tack 36~ again~t breaking tne ~eal between the tack ~ea~ portion 76 and the 5~
probe seat 78 wnen tne tack 36 is ~eing implanted.
Breakage of thi seal could cause the tack 36 to fall away from the pto~e 26 and drop into tne vitreous cavity 44.
Tne ceduced diameter of tne stub poction 74 facilitates gtasping with a foceign body foreceps in the event the tack 36 is accidentally dropped into tne vitreous cavity 44.
The ou~er dimension of tne head 56 is l9-guage (about 0.040 inch) or less ~o tnat it can fit through a standard cannula for a 20-gauge wound.
Tne overall lengtn of tne tack 36 will vary and depends primarily on tne thickness of the retina, cnoroid, and sclera of a particular patient. Tnat lS is, tne retaining portion 54 of tacks u~ed in adult patients is lon~er than that for tack~ used in c~ildren. As a guide, tne overall length of the tack 36 can be in tne ocder of about 0.060 to 0.110 incn.
The retaining portion 54 can have ~ length of about 0. 01 to 0 . 02 and an ou~er dimension about 0. 020 incn. Tne piercing Rection 52 can nave a lengtn of about 0.025 to 0.045 inch. The overall lengtn of the head 56 can be about 0. 02 to 0 . 03 incn and tne lengtn of tne stu~ portion 74 can be a~out 0.015 to 0. 02 inch.
Fig. 4 illustrates an alternate embodiment of tne retinal tac~ designed for use in children and otner patients having thinner cetina, choroid, and sclera In tni~ embodiment, the length of the piercing section 52a of tne retinal tack 36a i~ sligntly less, the length of the retaining portion 54a is shorter (but still approxim~tely tne thickne o the retina, cnoroid, and ~clera), tne retaining portion 54a includes a single groove 58 ~nd the head nas a different 3eating arCang~meQt.
More specifically, the entice outer sueface 84 of tne head 56 is tapered radially inwardly in a rearward direction and serves ag a seat which ~ealinyly engages a complementary seat 86 in tne pro~e tip 36a when a negative pressure exists in the p~o~e interioc passage 28a. In tnis embodiment, lateral ~upport for tne tac~ 56a depends entirely on 3urface contact between the tapered surface 84 of tne n~ad 56a and tne probe seat 86. Tnese two surfaces are configured to provide a tight taper-to-tapec fit.
Tne angle of ~aper for t~e head surface 84 and the probe seat preferably i5 about 10 to 20.
Witn an angle of taper ~reater than about 20, applica~ion of celatively small torques on tne forward end of tne tack 36a will ~reak tne ~eal ~etw~en tne head surface 84 and tne probe seat 86.
On tne otner hand, witn an angle of taper les~ tnan about 10, tne wall3 of the pcobe tip 36a become quite fragile and make it more difficult to pick up tacks.
It ShOUld be under~tood that both tne head arrangements illu~trated in Figs. 3 and 4 can be used on retinal t~cks having a retaining section including one or a plucality of grooves.
~5 The retinal tack can be fabricated from various celatively hard, inert, non-blood corrosive materials suit~ble for u~e in ~ numan body, iw luding commercially pure titanium and plastlc materials such as polyacetal3 and polyetnylmethacrylate. At the pre~ent time, commercially pure, Gr~d~ 4 titaminum is prefered because it can be macnined to provide tne de ired configurational featuEes, particarly a ~narp point on the piercing portion, the sharp co~ner ~etween the front side walls of tne grooves and tne jjl5 3~
;11-outer sucface of tne retaining portion and tne tapered seat on tne head.
From tne foregoing description, one skilled in the art can easily ~scectain the essential cnaracteristics of tne invention and, without departing from the spirit and scope tnereof, make various cnanges and modifications to adapt it to various usages.
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A retinal tack for securing a human patient's de-tached retina to the choroid comprising:
a pointed forward end portion for piercing through the patent's retina, choroid, and sclera;
an elongated retaining portion extending rearwardly from said forward end portion and having a longitudinal dimension approximating the thickness of the patient's retina, choroid, and sclera, said retaining portion including one or more circumferen-tially-extending grooves for receiving sclera tissue displaced by said forward end portion during insertion therethrough; and an enlarged head extending rearwardly from said retaining portion and having a radially outwardly extending flange portion for engaging the retina in the area surrounding the opening formed by said forward end portion.
a pointed forward end portion for piercing through the patent's retina, choroid, and sclera;
an elongated retaining portion extending rearwardly from said forward end portion and having a longitudinal dimension approximating the thickness of the patient's retina, choroid, and sclera, said retaining portion including one or more circumferen-tially-extending grooves for receiving sclera tissue displaced by said forward end portion during insertion therethrough; and an enlarged head extending rearwardly from said retaining portion and having a radially outwardly extending flange portion for engaging the retina in the area surrounding the opening formed by said forward end portion.
2. A retinal tack according to claim 1, in combination with a tubular probe having a tip including a seat for receiving a portion of said tack head and an interior passage adapted for connection in fluid communication with a source of subatmospheric pressure; and wherein said head includes a seat portion which is received by and sealingly engages the seat in the probe tip.
3. A retinal tack according to claim 2, wherein said head includes a collar extending rearwardly from said flange and a reduced stub portion extending rearwardly from said collar; and said tack seat portion includes a tapered portion which is tapered radially inwardly in a rearward direction and connects said stub portion with said collar.
4. A retinal tack according to claim 2, wherein said tack has a longitudinal axis and said flange extends generally perpendicularly to said longitudinal axis.
5. A retinal tack according to claim 2, wherein said head includes a tapered outer surface which comprises said tack seat portion.
6. A retinal tack according to claim 5, wherein the taper of said outer surface extends at an angle of about 10° to about 20° to said longitudinal axis.
7. A retinal tack according to claim 1, wherein said forward end portion is generally conical;
said retaining portion has a generally cylindrical outer surface; and each of said grooves has radially outwardly extending forward and rear side walls and said forward side wall forms a sharp corner with said outer surface of said retaining portion.
said retaining portion has a generally cylindrical outer surface; and each of said grooves has radially outwardly extending forward and rear side walls and said forward side wall forms a sharp corner with said outer surface of said retaining portion.
8. A retinal tack according to claim 3, wherein said rear side wall of each of said grooves is outwardly inclined in a rearward direction.
9. A retinal tack according to claim 1, wherein said retaining portion includes a plurality of said grooves in long-itudinally spaced relationship.
10. A retinal tack according to claim 1, made from a commercially pure grade titanium.
11. A retinal tack for securing a patient's detached retina to the choroid comprising:
a generally conical, pointed, forward end portion for piercing through the patient's retina, choroid, and sclera;
an elongated retaining portion having a generally cylindrical outer surface extending rearwardly from said forward end portion and having a longitudinal dimension approximating the thickness of the patient's retina, choroid, and sclera, said retaining portion including one or more circumferentially-extending grooves for receiving sclera tissue displaced by said forward end portion during insertion therethrough; and an enlarged head extending rearwardly from said retaining portion and having a radially outwardly extending flange portion for engaging the retina of the area surrounding the open-ing formed by said forward end portion, said head having a rear portion including an annular seat;
in combination with a tubular probe having a tip including a seat for receiving and sealingly engaging said tack annular seat and an interior passage adapted for connection in fluid communication with a source of subatmospheric pressure.
a generally conical, pointed, forward end portion for piercing through the patient's retina, choroid, and sclera;
an elongated retaining portion having a generally cylindrical outer surface extending rearwardly from said forward end portion and having a longitudinal dimension approximating the thickness of the patient's retina, choroid, and sclera, said retaining portion including one or more circumferentially-extending grooves for receiving sclera tissue displaced by said forward end portion during insertion therethrough; and an enlarged head extending rearwardly from said retaining portion and having a radially outwardly extending flange portion for engaging the retina of the area surrounding the open-ing formed by said forward end portion, said head having a rear portion including an annular seat;
in combination with a tubular probe having a tip including a seat for receiving and sealingly engaging said tack annular seat and an interior passage adapted for connection in fluid communication with a source of subatmospheric pressure.
12. A retinal tack according to claim 11, wherein the outermost diameter of said retaining portion is substantially constant along the length thereof.
13. A retinal tack according to claim 12, wherein said head includes a collar extending rearwardly from said flange and a reduced stub portion extending rearwardly from said collar; and said tack seat includes a tapered portion which is tapered radially inwardly in a rearward direction and connects said stub portion with said collar.
14. A retinal tack according to claim 12, wherein said head includes a tapered outer surface which comprises said tack seat portion.
15. A retinal tack according to claim 12, wherein said retaining portion includes a plurality of said grooves in long-itudinally spaced relationship, each of said grooves having radially outwardly extending forward and rear sidewalls, said forward sidewall forming a sharp corner with said outer surface of said retaining portion and said rear sidewall being outwardly inclined in a rearward direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000506653A CA1258355A (en) | 1986-04-15 | 1986-04-15 | Retinal tack and method for implanting same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000506653A CA1258355A (en) | 1986-04-15 | 1986-04-15 | Retinal tack and method for implanting same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1258355A true CA1258355A (en) | 1989-08-15 |
Family
ID=4132890
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000506653A Expired CA1258355A (en) | 1986-04-15 | 1986-04-15 | Retinal tack and method for implanting same |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1258355A (en) |
-
1986
- 1986-04-15 CA CA000506653A patent/CA1258355A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |