CA1193936A - Microsurgical instrument - Google Patents
Microsurgical instrumentInfo
- Publication number
- CA1193936A CA1193936A CA000399412A CA399412A CA1193936A CA 1193936 A CA1193936 A CA 1193936A CA 000399412 A CA000399412 A CA 000399412A CA 399412 A CA399412 A CA 399412A CA 1193936 A CA1193936 A CA 1193936A
- Authority
- CA
- Canada
- Prior art keywords
- instrument
- probe means
- cutting member
- probe
- canal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
Abstract.
A microsurgical instrument for performing selective trabeculectomy in surgical treatment of glaucoma includes flexible probe means (A) and a cutting member (C) fixed to the same, The cutting member comprises two knife blades (C1,C2) protruding in different directions from the probe means and each providing at least one sharp edge (E1,E2) turned towards a free end of the probe means.
The instrument is designed to be pulled between two incisions in the eye wall with the probe means foremost through the Canal of Schlemm at the transition between cornea and sclera, thereby cutting away the inner wall of the canal and the corresponding part of the trabecular mesh-work located in the canal. The aqueous humour of the eye then gains access to the outer wall of the Canal of Schlemm with its drainage outlets leading out of the eye.
A microsurgical instrument for performing selective trabeculectomy in surgical treatment of glaucoma includes flexible probe means (A) and a cutting member (C) fixed to the same, The cutting member comprises two knife blades (C1,C2) protruding in different directions from the probe means and each providing at least one sharp edge (E1,E2) turned towards a free end of the probe means.
The instrument is designed to be pulled between two incisions in the eye wall with the probe means foremost through the Canal of Schlemm at the transition between cornea and sclera, thereby cutting away the inner wall of the canal and the corresponding part of the trabecular mesh-work located in the canal. The aqueous humour of the eye then gains access to the outer wall of the Canal of Schlemm with its drainage outlets leading out of the eye.
Description
3~3~
Microsurgical instrument.
The present invention rela-tes -to a microsurgical cutting ins-trumen-t to be used in surgical -treatmen-t of glaucoma by means of a novel opera-tional procedure, which significantly may be called "selec-tive -trabeculectomy".
Glaucoma is an ailment which enhanced inner pressure in the eyeball. Within the eye aqueou.shumour is produced at a fairly constant rate. This liquld is drained out through filterlike tissue (trabecular meshwork) in the angle be-tween iris and cornea into a collector canal running sircularly along the transi-tion between cornea and sclera (Canal of Schlemm), and from this canal through 20-30 drainage outlets in the eye wall into blood vessels (water veins).
The cause of ylaucoma is believed -to be a type of "clogging" of the trabecular rneshwork, so that the out-flow resistance increases. Then, also the pressure ir.-crease.s to allow the SaMe volurne of liquid to be drained out per tirne unit. All treatment aims at reducing the eye pressure. Such treatment is primarily medical, but when this is intolerable and/or :insufficient, surglcal treatment is used.
The surgical treatment may be subdivided according to three principles,.. namely:
1. Operations aiming at reduced production of aqueous humour.
Microsurgical instrument.
The present invention rela-tes -to a microsurgical cutting ins-trumen-t to be used in surgical -treatmen-t of glaucoma by means of a novel opera-tional procedure, which significantly may be called "selec-tive -trabeculectomy".
Glaucoma is an ailment which enhanced inner pressure in the eyeball. Within the eye aqueou.shumour is produced at a fairly constant rate. This liquld is drained out through filterlike tissue (trabecular meshwork) in the angle be-tween iris and cornea into a collector canal running sircularly along the transi-tion between cornea and sclera (Canal of Schlemm), and from this canal through 20-30 drainage outlets in the eye wall into blood vessels (water veins).
The cause of ylaucoma is believed -to be a type of "clogging" of the trabecular rneshwork, so that the out-flow resistance increases. Then, also the pressure ir.-crease.s to allow the SaMe volurne of liquid to be drained out per tirne unit. All treatment aims at reducing the eye pressure. Such treatment is primarily medical, but when this is intolerable and/or :insufficient, surglcal treatment is used.
The surgical treatment may be subdivided according to three principles,.. namely:
1. Operations aiming at reduced production of aqueous humour.
2. Fistulizing procedures, i.e. surgical provision of artificial slits in the eye walls, through which the liquid may sip out of the eye.
.~
.~
3~3~
3. Operations on the trabecular meshwork. ~xisting procedures of this kind are of two types, i.e.:
a) Approach through -the anterior chamber of -the eye by means of goniotomy or cautery of the trabecular mesh-work with laser beams.
b) Approach through the Canal of Sc}llemm. Such approach consi.sts in opening this canal through a radial incision in the eye wall ahove -the canal and insertio oE a blunt p~;obe or probe means with a cutting edye (trabeculotome). This instrument is then manipulated in such a way that it tears open or cuts through the trabe-cular meshwork into the anterior chamber of the eye. With such procedure a narrow slitlike opening is formed through the trabecular meshwork. Such slits exhibit, however, a considerable tendency -to close.
In order to inhibit such closure it is an object of the invention to provide a microsurgical instrumen-t, which through appropriate use may form a permanent opening from the anterior chamber of the eye to the Canal of Schle.rnm by selective removal of the lnner wall of this canal along a certain sector. Irl this manner the aqueous humour gains direc-t access to the outer wall of the Canal o~ Schlemm, which has outlets or drainage canals, so tha-t normal drainage of aqueous humour may be re-established.
Thus, the invention concerns a mucrosurgical instrument for performing selective traveculectomy in surgical treat-ment of glaucoma, the instrument including flexible probe means and a cutting member fixed to the same. On this background the general inventive fea-ture of the instru-ment is that the cutting member comprises two ]cnife blades protruding in different directions from -the probe and each p~oviding at least one sharp cutting edge turned towards ~3~
a Eree end of the prohe means.
ThiS instrumen-t may be called a trabeculectome, clS it is designed to be pulled -through the Canal of: Schlemm along a certain peripherlal sector of the eye. By this the inner wall of t'he cana~ and the correspondin~ por-tion of the 0.1 mm thic]c trabeular meshwor]c are cu-t away.
As indicated, the trabeculec-tome consists of probe means and a cutting member. The probe means is preferably knob-shaped at the extreme end and made of fle~ible material, but -this still sufficiently rigid to be insert-ed into and direc-ted through the Canal of Schlemm. The cutting member has a double-cutting knife, the two cutting edges of which are angularly separated to such extent that the issuing V-orm fits into the scleral yroove in the eye wall, in which -the trabecular meshwork is embedded. Advantageously, the cuttinc~ rnember is assyme-trical ln such a manner -that the knife blade that projects perpendicularly in-to the anterior chamber to-wards the iris, is short, whereas the blade that pro-5ects obli~uely into the anterior chamber and forms a small angle with the back side of -the cornea, is longer.
Th~s feature stabilizes the correct position of the knie.
The probe means of the trabeculectome i.s directed through an incision in the eye wa].l into and along -the Canal of Schlemm, and is pulled out through another incision at a certain distance rom the first one. The cut-ting member of the trabeculectome is pulled after the probe means through the Canal of Schlemm w.ith the two ~niEe edges pro5ecting into the anterior chamber of the eye and thereby cutting away a strip of the trabecular tissue and the inner wall of the Canal of Schlemm which are located between the cutting edges. This tissue strip is prefer-3~3~
ably removed together with the trabeculectome when itis pulled ou-t through the seconcl incision in the eye wall. Such removal of -the tissue strip rnay be secured by mountiny one or more hooks :in the angle be-tween the two knife edges in order to catch -the cut away strip and carry it out of -the eye.
The microsurgical instrumen-t accordiny to the in~ention allows a surgical procedure which secures a permanent broad opening be-tween the an-terior chamher o the eye and the ou-tlets from the Canal of Schlemm by removing -the trabecular meshwor~< and the inner wall of the canal.
Tissue removal together with maintained cell casing on the outer wall of the Canal of Schlemm make a closure of this opening improbable, even in -the long run. `
Experiences with this method up to now suggest a low rate of complications, so that the operational indica-tions probably may be extended. I'his means that the patients may be operated a-t an earlier stage and thus expensive and troublesome medical treatrnent is avoided.
The invention will now be explained in more de-tail with reference to exemplified embodiments as shown in the accompanying drawings, in which ~igure 1 shows a first embodiment of -the instrument in a cross-section throuyh the cutting member at righ-t angle to the longitudinal axis of the probe means.
Figure 2 is a side elevation oE the instrument shown in Figure 1.
Fiyure 3 shows the instrument in Figures 1 and 2 in perspective view.
i ~93~6 Figure 4 is a side elevation of another embodirnent of the instrument, and Figure 5 shows a cross-section through the cutting member at right angle to the longitudinal axis o~ the probe means in the embodiment of Figure 4.
The probe means A is in the embodiment shown in Fig. 1-3 a monofilament of nylon, which is fused at one end to Eorm a rounded knob. The other end of the probe is inserted into a hole in s-teel member B and rigidly clamped to this member. The knife member C is formed from a 1/100 - 5/100 mm thick stainless steel foil, which is finely sharpened at the front side and bent into an approximate V-form adapted to the local anatomical featuresof the eye at the Canal of Schlemm and the trabecular meshwork. The member C is fixed to the member B and thereby also the probe A by means of a two-component epoxy glue. Point welding technique ma~ also be used, if the probe means is mounted on the member B after the welding s-tep. An arrow above the probe in Fig. 2 shows the pulling direction in use.
Between the knife blades a barbed hook is fixed to the steel member B in order to catch the tissue strip which is cut free between the knives. This hook is also fastened by means of epoxy resin. Finally, a layer of epoxy resin is applied to the joints and transitions between the steel member B and the ~robe ~ to provide a completely smooth surface. Tefl~ and similar polymers may also be used as covering layer and silicone is considered particularly advantageous for this purpose.
Another embodiment is illustrated in the Figures 4 and 5.
In this case the probe is made of flexible metal and welded to the knife member. The extreme rear end of the probe is bent forward between the knife blades to form a small sharp *) a trademark 3a~3~
hook. All joints are provided with a cover of epoxy resin and the probe is furnished with a layer of resin at the end to form a ~inely rounded knob.
The knife blades C1, C2 need not necessarily have a free end. Thus, the extreme ends of the knife blades may well be interconnected to form a closed knife blade ring, e.g.
of approximate triangular shape. The cut-away tissue strip may then be captured by closing the rear opening of the knife ring, thereby catching the strip in the "container"
thus formed.
The instrument must necessarily be quite small to allow the intended surgical treatment of the eye. Thus, in the illustrated embodiments the probe has a diameter of approximately 0.25 mm and a length of t,-he order of magni-tude 4-8 crn and rather freely adaptable to the requirements of the eye surgeon. The shorter knife of the cutting member may suitably have a length of about 0.7 - 1.~ mm, while the longer, preferably curved knife may have a length of 1.5 -1.8 mm. I'he width of the knives may be of the order of magnitude 0.3 - 0.5 rnm.
In the embodiments shown in the drawings and described above the cutting member is fixed at one end of the probe means.
However, as indicated in the following patent claims, the cutting member may well be fixed to the probe at another location, e~g. on the central part of the same. The portion of the probe projecting from the rear side of the cutting member may then be used for improved steering of the instrument, when it is guided between the two incisions in the eye wall. If the cutting member is located approximate-ly centrally on the probe, the protruding knife blades may further be provided with a cutting edge on both sides, so that the ins-trument may be effectively pulled in both directions through the Canal oE Schlernm.
Although the cutting edges are shown in -the drawing to form essentially right angles with the longitudinal axes of the probe means, the edges may a:Lso according -to the invention advantageously be inclined at an angle of 45 -90 in the pulling direction with respect -to the probe axis. An inwards directed radlal force is tllell exercised against the tissue strip during -the movernen-t of the cutting member through the Canal of Schlemrn.
3. Operations on the trabecular meshwork. ~xisting procedures of this kind are of two types, i.e.:
a) Approach through -the anterior chamber of -the eye by means of goniotomy or cautery of the trabecular mesh-work with laser beams.
b) Approach through the Canal of Sc}llemm. Such approach consi.sts in opening this canal through a radial incision in the eye wall ahove -the canal and insertio oE a blunt p~;obe or probe means with a cutting edye (trabeculotome). This instrument is then manipulated in such a way that it tears open or cuts through the trabe-cular meshwork into the anterior chamber of the eye. With such procedure a narrow slitlike opening is formed through the trabecular meshwork. Such slits exhibit, however, a considerable tendency -to close.
In order to inhibit such closure it is an object of the invention to provide a microsurgical instrumen-t, which through appropriate use may form a permanent opening from the anterior chamber of the eye to the Canal of Schle.rnm by selective removal of the lnner wall of this canal along a certain sector. Irl this manner the aqueous humour gains direc-t access to the outer wall of the Canal o~ Schlemm, which has outlets or drainage canals, so tha-t normal drainage of aqueous humour may be re-established.
Thus, the invention concerns a mucrosurgical instrument for performing selective traveculectomy in surgical treat-ment of glaucoma, the instrument including flexible probe means and a cutting member fixed to the same. On this background the general inventive fea-ture of the instru-ment is that the cutting member comprises two ]cnife blades protruding in different directions from -the probe and each p~oviding at least one sharp cutting edge turned towards ~3~
a Eree end of the prohe means.
ThiS instrumen-t may be called a trabeculectome, clS it is designed to be pulled -through the Canal of: Schlemm along a certain peripherlal sector of the eye. By this the inner wall of t'he cana~ and the correspondin~ por-tion of the 0.1 mm thic]c trabeular meshwor]c are cu-t away.
As indicated, the trabeculec-tome consists of probe means and a cutting member. The probe means is preferably knob-shaped at the extreme end and made of fle~ible material, but -this still sufficiently rigid to be insert-ed into and direc-ted through the Canal of Schlemm. The cutting member has a double-cutting knife, the two cutting edges of which are angularly separated to such extent that the issuing V-orm fits into the scleral yroove in the eye wall, in which -the trabecular meshwork is embedded. Advantageously, the cuttinc~ rnember is assyme-trical ln such a manner -that the knife blade that projects perpendicularly in-to the anterior chamber to-wards the iris, is short, whereas the blade that pro-5ects obli~uely into the anterior chamber and forms a small angle with the back side of -the cornea, is longer.
Th~s feature stabilizes the correct position of the knie.
The probe means of the trabeculectome i.s directed through an incision in the eye wa].l into and along -the Canal of Schlemm, and is pulled out through another incision at a certain distance rom the first one. The cut-ting member of the trabeculectome is pulled after the probe means through the Canal of Schlemm w.ith the two ~niEe edges pro5ecting into the anterior chamber of the eye and thereby cutting away a strip of the trabecular tissue and the inner wall of the Canal of Schlemm which are located between the cutting edges. This tissue strip is prefer-3~3~
ably removed together with the trabeculectome when itis pulled ou-t through the seconcl incision in the eye wall. Such removal of -the tissue strip rnay be secured by mountiny one or more hooks :in the angle be-tween the two knife edges in order to catch -the cut away strip and carry it out of -the eye.
The microsurgical instrumen-t accordiny to the in~ention allows a surgical procedure which secures a permanent broad opening be-tween the an-terior chamher o the eye and the ou-tlets from the Canal of Schlemm by removing -the trabecular meshwor~< and the inner wall of the canal.
Tissue removal together with maintained cell casing on the outer wall of the Canal of Schlemm make a closure of this opening improbable, even in -the long run. `
Experiences with this method up to now suggest a low rate of complications, so that the operational indica-tions probably may be extended. I'his means that the patients may be operated a-t an earlier stage and thus expensive and troublesome medical treatrnent is avoided.
The invention will now be explained in more de-tail with reference to exemplified embodiments as shown in the accompanying drawings, in which ~igure 1 shows a first embodiment of -the instrument in a cross-section throuyh the cutting member at righ-t angle to the longitudinal axis of the probe means.
Figure 2 is a side elevation oE the instrument shown in Figure 1.
Fiyure 3 shows the instrument in Figures 1 and 2 in perspective view.
i ~93~6 Figure 4 is a side elevation of another embodirnent of the instrument, and Figure 5 shows a cross-section through the cutting member at right angle to the longitudinal axis o~ the probe means in the embodiment of Figure 4.
The probe means A is in the embodiment shown in Fig. 1-3 a monofilament of nylon, which is fused at one end to Eorm a rounded knob. The other end of the probe is inserted into a hole in s-teel member B and rigidly clamped to this member. The knife member C is formed from a 1/100 - 5/100 mm thick stainless steel foil, which is finely sharpened at the front side and bent into an approximate V-form adapted to the local anatomical featuresof the eye at the Canal of Schlemm and the trabecular meshwork. The member C is fixed to the member B and thereby also the probe A by means of a two-component epoxy glue. Point welding technique ma~ also be used, if the probe means is mounted on the member B after the welding s-tep. An arrow above the probe in Fig. 2 shows the pulling direction in use.
Between the knife blades a barbed hook is fixed to the steel member B in order to catch the tissue strip which is cut free between the knives. This hook is also fastened by means of epoxy resin. Finally, a layer of epoxy resin is applied to the joints and transitions between the steel member B and the ~robe ~ to provide a completely smooth surface. Tefl~ and similar polymers may also be used as covering layer and silicone is considered particularly advantageous for this purpose.
Another embodiment is illustrated in the Figures 4 and 5.
In this case the probe is made of flexible metal and welded to the knife member. The extreme rear end of the probe is bent forward between the knife blades to form a small sharp *) a trademark 3a~3~
hook. All joints are provided with a cover of epoxy resin and the probe is furnished with a layer of resin at the end to form a ~inely rounded knob.
The knife blades C1, C2 need not necessarily have a free end. Thus, the extreme ends of the knife blades may well be interconnected to form a closed knife blade ring, e.g.
of approximate triangular shape. The cut-away tissue strip may then be captured by closing the rear opening of the knife ring, thereby catching the strip in the "container"
thus formed.
The instrument must necessarily be quite small to allow the intended surgical treatment of the eye. Thus, in the illustrated embodiments the probe has a diameter of approximately 0.25 mm and a length of t,-he order of magni-tude 4-8 crn and rather freely adaptable to the requirements of the eye surgeon. The shorter knife of the cutting member may suitably have a length of about 0.7 - 1.~ mm, while the longer, preferably curved knife may have a length of 1.5 -1.8 mm. I'he width of the knives may be of the order of magnitude 0.3 - 0.5 rnm.
In the embodiments shown in the drawings and described above the cutting member is fixed at one end of the probe means.
However, as indicated in the following patent claims, the cutting member may well be fixed to the probe at another location, e~g. on the central part of the same. The portion of the probe projecting from the rear side of the cutting member may then be used for improved steering of the instrument, when it is guided between the two incisions in the eye wall. If the cutting member is located approximate-ly centrally on the probe, the protruding knife blades may further be provided with a cutting edge on both sides, so that the ins-trument may be effectively pulled in both directions through the Canal oE Schlernm.
Although the cutting edges are shown in -the drawing to form essentially right angles with the longitudinal axes of the probe means, the edges may a:Lso according -to the invention advantageously be inclined at an angle of 45 -90 in the pulling direction with respect -to the probe axis. An inwards directed radlal force is tllell exercised against the tissue strip during -the movernen-t of the cutting member through the Canal of Schlemrn.
Claims (12)
1. Microsurgical instrument for performing selective trabeculectomy in surgical treatment of glaucoma, the instrument including flexible probe means and a cutting member fixed to the same, characterized in that the cutting member comprises two knife blades protruding in different directions from the probe and each providing at least one sharp cutting edge turned towards a free end of the probe means.
2. Instrument as claimed in claim 1, characterized in that at least one catching device for cut-away tissue is mounted on the cutting member behind the sharp cutting edges.
3. Instrument as claimed in claim 1, characterized in that the two knife edges protrude in different length from the probe means, the shorter blade being straight and the longer having a pre-determined curvature.
4. Instrument as claimed in claim 3, wherein said curvature is complementary with the shape of the surface of the tissue to be cut away.
5. Instrument as claimed in claim 1 or 2, characterized in that the ends of the two knife blades remote from the probe are interconnected to form a closed knife blade ring.
6. Instrument as claimed in claim 2, characterized in that the catching device is constituted by one or more hooks with the hook opening turned towards a free end of the probe means.
7. Instrument as claimed in claim 2, characterized in that the catching device is constituted by a plate member connected with an edgefree rim of the knife blades and formed as a trapping hook, covering at least a part of the interspace between the knife blades.
8. Instrument as claimed in claims 1, 2 or 3, characterized in that the cutting edges of the knife blades for an angle of 45-90° with the longitudinal axis of the probe means.
9. Instrument as claimed in claims 1, 2 or 3, characterized in that the probe means is constituted by a synthetic fibre suture with a metallic holder clamped to the suture, e.g. at one end of the same, the cutting member being glued or welded to the holder.
10. Instrument as claimed in claims 1, 2 or 3, characterized in that the probe means is made from an elongated flexible metallic material one end of which is welded to the cutting member.
11. Instrument as claimed in claims 1, 2 or 3, characterized in that the probe means is made from an elongated, flexible metallic material covered with a layer of a plastics material, one end of the metallic material being moulded to the cutting member.
12. Instrument as claimed in claims 1, 2 or 3 characterized in that the cutting member is moulded in hard plastics material integrated with or assembled with the probe means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000399412A CA1193936A (en) | 1982-03-25 | 1982-03-25 | Microsurgical instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000399412A CA1193936A (en) | 1982-03-25 | 1982-03-25 | Microsurgical instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1193936A true CA1193936A (en) | 1985-09-24 |
Family
ID=4122413
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000399412A Expired CA1193936A (en) | 1982-03-25 | 1982-03-25 | Microsurgical instrument |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1193936A (en) |
-
1982
- 1982-03-25 CA CA000399412A patent/CA1193936A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |