The surgical techniques for reducing intraocular pressure (IOP) that were available prior to the invention of the trabeculectomy shows high incidence of severe side effects.
The guarded filtering process was created to increase the safety of IOP-lowering surgery. In 1968, Cairns were the first to declare success with the trabeculectomy.
The process of creating a fistula between the subconjunctival area and anterior chamber is known as trabeculectomy.
When glaucoma patients have a blocked or malfunctioning natural trabecular outflow route, this gives alternate ways of aqueous fluid filtration. The objective is to provide the ideal flow rate without leading to over-filtration.
Its effectiveness depends on the fistula’s continuing patency and filtering bleb’s continued capacity to absorb water.
Both the surgical technique and the intraoperative and postoperative wound healing modulation methods are critical to the procedure’s effectiveness.
Indications
Primary open-angle glaucoma
Secondary open-angle glaucoma
Primary angle-closure glaucoma not responsive to iridotomy
Childhood glaucomas
Secondary angle-closure glaucoma
Contraindications
Eyes with previous failed trabeculectomy
Neovascular glaucoma with active neovascularization
Uveitic glaucoma
Eyes with severely scarred conjunctiva
Blind eyes
Outcomes
Equipment required
Speculum
Forceps
Scissors
Needle holders
operating microscope
Electrocautery or diathermy
Anterior chamber opening/sclerostomy
Patient Preparation:
Depending on the patient and surgeon’s preferences, the patient’s overall health, and the anticipated length of the treatment for that specific case, a tracheculectomy can be carried out under either local or general anesthesia.
Patient Positioning:
If the operation is done at the superior or superonasal limbus, the patient is in a supine position, and the surgeon sits overhead.
The surgeon may decide to sit superotemporal to the patient’s head if the surgery is performed at the superotemporal limbus.
Figure 1. Damages eye for Trabeculectomy
Technique
Step 1: Globe fixation
The eye must be moved away from the surgical site to increase the exposure of the limbus and conjunctiva at the location. Even while a very willing patient under topical or subconjunctival anesthetic might be able to perform this on their own is usually required.
A corneal traction suture can be attached in several places and pull the eye in different directions without puncturing the conjunctiva.
Placing a corneal traction suture involves passing a 7-0 or 8-0 non-slippery suture through half to two-thirds of the corneal thickness parallel to the surgical site, around 1-2 mm from the limbus using a spatulated needle.
After the eye has been moved in the proper direction, sterile tape or a clamp is used to secure the suture to the drapes.
For those who do extracapsular cataract extraction, the application of a superior rectus traction suture is not unfamiliar. With large-toothed forceps, the superior rectus muscle is grabbed close to its insertion and pushed away from the sclera to introduce a superior rectus traction suture.
The globe is then made to rotate downward by passing a 4-0 or 5-0 non-slippery suture on a round needle beneath the muscle and securing it above the eye.
Step 2: Anterior chamber access
It is necessary to establish anterior chamber (AC) access before accessing the AC at the surgical site. By injecting or withdrawing fluid, the surgeon may control the IOP and the AC depth.
A needle or blade can be used to create the side port or paracentesis site. To prevent unintentional lens damage, the winding track should be parallel to the iris and away from the lens.
Step 3: Conjunctival incision and dissection
The freshly formed fistula closes and scars because of inflammation. To lessen irritation, the conjunctiva must be handled gently. The conjunctiva must be cut with sharp scissors and grasped with nontoothed forceps.
A fornix-based flap requires cutting the conjunctiva near the limbus, but not so close as to damage the limbal stem cells. Keep in mind that leaving big, asymmetrical conjunctival tags might make it difficult to dissect the scleral flap.
At one or both ends of the limbal incision, a little radial relaxing incision may be created if necessary. Approximately 2 mm from the limbus, the Tenon capsule insertion is revealed, and the Tenon capsule is freed from its insertion without causing undue dissection of the conjunctiva.
The sub-Tenon plane is then used for the dissection. The conjunctiva and Tenon capsule do not need to be separated.
The conjunctiva and Tenon capsule are cut as far away from the limbus as feasible when a limbus-based flap is performed. This should ideally be done 8-10 mm away from the limbus.
Step 4: Scleral flap dissection
The cautery tip is used to define a partial thickness limbus-based scleral flap, or the sclera is indented. At an angle perpendicular to the globe, a sharp blade is used to cut the flap’s edges. To reach the limbus, the flap is subsequently raised and divided between the scleral lamellae.
To prevent premature entrance into the AC, the flap dissection blade should be oriented somewhat anteriorly as it approaches the cornea, following the curve of the peripheral cornea.
The thickness of the flap should be between one-third and one-half of the scleral thickness. A flap that is too thin might become extremely brittle, whereas a flap that is too thick could impede aqueous flow.
The flap’s dimensions vary, but it should ideally be 3–4 mm broad and 2-3 mm radially. The scleral flap must be at least one sclerostomy broad for the outside edge of the flap and the sclerostomy edge to be separated.
Step 5: Anterior chamber entry
For the sclerostomy to be made well anterior to the iris plane, the internal scleral flap dissection should reach the peripheral cornea. In eyes with shallow ACs, this is particularly crucial to avoid the iris or ciliary body being trapped in the sclerostomy.
A blade is used to penetrate the AC near the scleral flap’s anterior limit. The angle of the blade should be more posterior than the flap’s plane of dissection. To avoid excessive AC shallowing, try not to cause the wound to gape during this procedure.
Step 6: Sclerostomy (sclerectomy) and peripheral iridectomy
A punch, blade, or pair of scissors is then used to remove the posterior edge of the incision made into the AC. To prevent a lamellar or imperforate sclerostomy, make sure that the whole thickness of the tissue is trapped between the punch blades.
The iris is then gripped with forceps via the freshly formed aperture, and tiny, sharp scissors are used to make a peripheral iridectomy. For the iridectomy to avoid incarcerating the iris into the incision, the base should be broader than the sclerostomy.
Step 7: Scleral flap closure
A mix of basic interrupted, releasable, or adjustable 10-0 nylon sutures is used to seal the scleral flap. The flap portion covering the sclerostomy is carefully avoided by placing the sutures at the flap boundaries.
Avoid areas with an excessively narrow flap. The suture “whiskers” should not protrude through the bleb; therefore, the knots should be concealed.
Numerous ways for sutures that are adjustable and releasable have been reported. Simple interrupted sutures are easier to put than releasable or adjustable sutures. Without the use of an argon laser, the surgeon can remove sutures at the slit lamp using releasable sutures (laser suture lysis). If the postoperative IOP is more than would be preferred, this is used to reduce it.
Assessment of the aqueous flow through the flap is done following the insertion of the initial flap sutures. Fluid is injected through the paracentesis track to first reconstruct the AC. A little sponge is then used to dry the flap edges, and the stability of the AC and the quantity of water leakage are noted.
Because there are several non-invasive and successful treatments for postoperatively high IOP but very few for postoperatively low IOP.
Step 8: Conjunctival closure
When the flap suture knots are buried and there is adequate aqueous flow through the flap, conjunctival closure can start. The conjunctiva should be handled carefully, and just the Tenon capsule should be gripped when it is feasible, much like when it is first dissected.
Preferred are circular (vascular) needles and nylon 10-0 sutures. Although they may cause irritation of the conjunctiva, absorbable sutures can be utilized. When suturing the conjunctiva to the limbus, spatulated (side-cutting) needles can also be utilized.
A simple running suture or an interlocking running suture can be used to sew limbus-based conjunctival flaps. The conjunctiva and Tenon capsule can be closed concurrently, or it can be closed in layers. Tenon capsule tags that protrude from the incision should be avoided as they may result in leaking or the creation of a fistula.
Conjunctiva-to-cornea closure occurs when the conjunctiva is cut flush with the limbus, while conjunctiva-to-conjunctiva closure occurs when a narrow conjunctival skirt remains connected to the limbus.
An indented line from the nasal to the temporal wing sutures indicates that the conjunctiva has expanded between them.
All sutures must to be positioned or knotted such that the knots are buried in the limbal tissue or beneath the conjunctiva. If it is not feasible to conceal the knots, the suture ends might be left a little bit longer to lessen the feeling of a foreign body that would result from short suture whiskers sticking out.
The surgical techniques for reducing intraocular pressure (IOP) that were available prior to the invention of the trabeculectomy shows high incidence of severe side effects.
The guarded filtering process was created to increase the safety of IOP-lowering surgery. In 1968, Cairns were the first to declare success with the trabeculectomy.
The process of creating a fistula between the subconjunctival area and anterior chamber is known as trabeculectomy.
When glaucoma patients have a blocked or malfunctioning natural trabecular outflow route, this gives alternate ways of aqueous fluid filtration. The objective is to provide the ideal flow rate without leading to over-filtration.
Its effectiveness depends on the fistula’s continuing patency and filtering bleb’s continued capacity to absorb water.
Both the surgical technique and the intraoperative and postoperative wound healing modulation methods are critical to the procedure’s effectiveness.
Primary open-angle glaucoma
Secondary open-angle glaucoma
Primary angle-closure glaucoma not responsive to iridotomy
Childhood glaucomas
Secondary angle-closure glaucoma
Eyes with previous failed trabeculectomy
Neovascular glaucoma with active neovascularization
Uveitic glaucoma
Eyes with severely scarred conjunctiva
Blind eyes
Speculum
Forceps
Scissors
Needle holders
operating microscope
Electrocautery or diathermy
Anterior chamber opening/sclerostomy
Patient Preparation:
Depending on the patient and surgeon’s preferences, the patient’s overall health, and the anticipated length of the treatment for that specific case, a tracheculectomy can be carried out under either local or general anesthesia.
Patient Positioning:
If the operation is done at the superior or superonasal limbus, the patient is in a supine position, and the surgeon sits overhead.
The surgeon may decide to sit superotemporal to the patient’s head if the surgery is performed at the superotemporal limbus.
Figure 1. Damages eye for Trabeculectomy
Step 1: Globe fixation
The eye must be moved away from the surgical site to increase the exposure of the limbus and conjunctiva at the location. Even while a very willing patient under topical or subconjunctival anesthetic might be able to perform this on their own is usually required.
A corneal traction suture can be attached in several places and pull the eye in different directions without puncturing the conjunctiva.
Placing a corneal traction suture involves passing a 7-0 or 8-0 non-slippery suture through half to two-thirds of the corneal thickness parallel to the surgical site, around 1-2 mm from the limbus using a spatulated needle.
After the eye has been moved in the proper direction, sterile tape or a clamp is used to secure the suture to the drapes.
For those who do extracapsular cataract extraction, the application of a superior rectus traction suture is not unfamiliar. With large-toothed forceps, the superior rectus muscle is grabbed close to its insertion and pushed away from the sclera to introduce a superior rectus traction suture.
The globe is then made to rotate downward by passing a 4-0 or 5-0 non-slippery suture on a round needle beneath the muscle and securing it above the eye.
Step 2: Anterior chamber access
It is necessary to establish anterior chamber (AC) access before accessing the AC at the surgical site. By injecting or withdrawing fluid, the surgeon may control the IOP and the AC depth.
A needle or blade can be used to create the side port or paracentesis site. To prevent unintentional lens damage, the winding track should be parallel to the iris and away from the lens.
Step 3: Conjunctival incision and dissection
The freshly formed fistula closes and scars because of inflammation. To lessen irritation, the conjunctiva must be handled gently. The conjunctiva must be cut with sharp scissors and grasped with nontoothed forceps.
A fornix-based flap requires cutting the conjunctiva near the limbus, but not so close as to damage the limbal stem cells. Keep in mind that leaving big, asymmetrical conjunctival tags might make it difficult to dissect the scleral flap.
At one or both ends of the limbal incision, a little radial relaxing incision may be created if necessary. Approximately 2 mm from the limbus, the Tenon capsule insertion is revealed, and the Tenon capsule is freed from its insertion without causing undue dissection of the conjunctiva.
The sub-Tenon plane is then used for the dissection. The conjunctiva and Tenon capsule do not need to be separated.
The conjunctiva and Tenon capsule are cut as far away from the limbus as feasible when a limbus-based flap is performed. This should ideally be done 8-10 mm away from the limbus.
Step 4: Scleral flap dissection
The cautery tip is used to define a partial thickness limbus-based scleral flap, or the sclera is indented. At an angle perpendicular to the globe, a sharp blade is used to cut the flap’s edges. To reach the limbus, the flap is subsequently raised and divided between the scleral lamellae.
To prevent premature entrance into the AC, the flap dissection blade should be oriented somewhat anteriorly as it approaches the cornea, following the curve of the peripheral cornea.
The thickness of the flap should be between one-third and one-half of the scleral thickness. A flap that is too thin might become extremely brittle, whereas a flap that is too thick could impede aqueous flow.
The flap’s dimensions vary, but it should ideally be 3–4 mm broad and 2-3 mm radially. The scleral flap must be at least one sclerostomy broad for the outside edge of the flap and the sclerostomy edge to be separated.
Step 5: Anterior chamber entry
For the sclerostomy to be made well anterior to the iris plane, the internal scleral flap dissection should reach the peripheral cornea. In eyes with shallow ACs, this is particularly crucial to avoid the iris or ciliary body being trapped in the sclerostomy.
A blade is used to penetrate the AC near the scleral flap’s anterior limit. The angle of the blade should be more posterior than the flap’s plane of dissection. To avoid excessive AC shallowing, try not to cause the wound to gape during this procedure.
Step 6: Sclerostomy (sclerectomy) and peripheral iridectomy
A punch, blade, or pair of scissors is then used to remove the posterior edge of the incision made into the AC. To prevent a lamellar or imperforate sclerostomy, make sure that the whole thickness of the tissue is trapped between the punch blades.
The iris is then gripped with forceps via the freshly formed aperture, and tiny, sharp scissors are used to make a peripheral iridectomy. For the iridectomy to avoid incarcerating the iris into the incision, the base should be broader than the sclerostomy.
Step 7: Scleral flap closure
A mix of basic interrupted, releasable, or adjustable 10-0 nylon sutures is used to seal the scleral flap. The flap portion covering the sclerostomy is carefully avoided by placing the sutures at the flap boundaries.
Avoid areas with an excessively narrow flap. The suture “whiskers” should not protrude through the bleb; therefore, the knots should be concealed.
Numerous ways for sutures that are adjustable and releasable have been reported. Simple interrupted sutures are easier to put than releasable or adjustable sutures. Without the use of an argon laser, the surgeon can remove sutures at the slit lamp using releasable sutures (laser suture lysis). If the postoperative IOP is more than would be preferred, this is used to reduce it.
Assessment of the aqueous flow through the flap is done following the insertion of the initial flap sutures. Fluid is injected through the paracentesis track to first reconstruct the AC. A little sponge is then used to dry the flap edges, and the stability of the AC and the quantity of water leakage are noted.
Because there are several non-invasive and successful treatments for postoperatively high IOP but very few for postoperatively low IOP.
Step 8: Conjunctival closure
When the flap suture knots are buried and there is adequate aqueous flow through the flap, conjunctival closure can start. The conjunctiva should be handled carefully, and just the Tenon capsule should be gripped when it is feasible, much like when it is first dissected.
Preferred are circular (vascular) needles and nylon 10-0 sutures. Although they may cause irritation of the conjunctiva, absorbable sutures can be utilized. When suturing the conjunctiva to the limbus, spatulated (side-cutting) needles can also be utilized.
A simple running suture or an interlocking running suture can be used to sew limbus-based conjunctival flaps. The conjunctiva and Tenon capsule can be closed concurrently, or it can be closed in layers. Tenon capsule tags that protrude from the incision should be avoided as they may result in leaking or the creation of a fistula.
Conjunctiva-to-cornea closure occurs when the conjunctiva is cut flush with the limbus, while conjunctiva-to-conjunctiva closure occurs when a narrow conjunctival skirt remains connected to the limbus.
An indented line from the nasal to the temporal wing sutures indicates that the conjunctiva has expanded between them.
All sutures must to be positioned or knotted such that the knots are buried in the limbal tissue or beneath the conjunctiva. If it is not feasible to conceal the knots, the suture ends might be left a little bit longer to lessen the feeling of a foreign body that would result from short suture whiskers sticking out.
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