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Trabeculectomy: A modified surgical technique
Trabeculectomy: A modified surgical technique Maurice H. Luntz, M.D., Abraham Schlossman, M.D.
ABSTRACT A modified surgical technique is described for trabeculectomy using contemporary limbal incisional techniques for a simplified dissection of the lamellar scleral flap, a technically easier operation, with smoothly dissected surfaces. The results and complications are comparable to those using the standard method. Key Words: trabeculectomy, tunnel incision
The surgical technique for trabeculectomy has remained essentially unaltered since Cairns' first described it in 1968. 2- 14 The procedure is highly effective, but performing a perfect, smooth dissection of the lamellar scleral flap and lamellar scleral corneal bed is technically difficult. The modified method described here, which uses contemporary limbal incisional techniques, allows for a simplified dissection of the lamellar scleral flap and a technically easier operation with extremely smooth surfaces. The procedure is based on the tunnel incision used for cataract surgery with phacoem ulsification.
SURGICAL TECHNIQUE
Conjunctival Flap (5x suggested magnification)
A 5.0 mm wide, fornix-based conjunctival flap is raised at the limbus, preferably in the superonasal quadrant. The advantages of a fornix-based conjunctival flap for trabeculectomy, as previously documented, 15 are ( 1) the Tenon's fascia is minimally traumatized, (2) there is better exposure of the limbal area, and (3) thinning of the limbal conjunctiva and overhang of the cornea are avoided. With the conjunctival flap pushed posteriorly, hemostasis of the exposed sclera is obtained.
Tunnel Incision
(1 Ox suggested magnification) With a crescent knife (Alcon), an incision is made parallel to the limbus and 2.0 mm posterior to the limbus, extending for 3.0 mm in width. The incision is carried down to approximately one-third of the scleral thickness. The same crescent knife is introduced at the base of this incision and dissects anteriorly toward the limbus, extending into the cornea just anterior to the
vascular arcade and forming a transscleral and intracorneal pocket at about one-third scleral depth with a width of3.0 mm. A 3.1 mm keratome is introduced into the scleral pocket and advanced to its anterior edge immediately anterior to the limbal-corneal vessels. The point of the keratome is then depressed and the keratome directed parallel to the plane of the iris and advanced into the anterior chamber for its full width, producing a 3.1 mm wide incision. This maneuver completes the tunnel incision into the anterior chamber (Figure 1).
Lifting the Lamellar Scleral Flap (5x suggested magnification)
A radial incision is fashioned at each side of this tunnel with a Vannas scissors. One blade of the Vannas scissors is introduced into the scleral tunnel at each side; the other blade lies over the sclera. The sclera is then incised, with the blade moving anteriorly just to within the limbus in clear cornea. The two radial incisions fashioned at each edge of the tunnel complete a 3.1 mm wide lamellar scleral flap hinged at the limbus (Figure 2). This dissection produces a smooth inner surface for the lamellar scleral flap and the adjacent sclerocorneal bed.
The Trabeculectomy (1 Ox suggested magnification)
The lamellar scleral flap is raised, exposing the underlying sclerocorneal bed. A Kelly Descemet's punch is advanced to the anterior cut edge of the sclerocorneal bed, and corneoscleral tissue is removed until a 2.0 mm x 2.0 mm trabeculectomy opening is fashioned (Figure 3). The iris will generally herniate through tbis opening, and an iridectomy is performed, ensuring that the base of the iridectomy is wider than the trabeculectomy opening.
From the Manhattan Eye, Ear, and Throat Hospital and the Mount Sinai School of Medicine, New York, New York. Reprint requests to Maurice H. Luntz, M.D., 121 East 60th Street, New York, New York 10022. 350
J CATARACT REFRACT SURG-VOL 20, MAY 1994
Fig. l.
(Luntz) A 3.1 mm keratome is advanced into the scleral pocket. The point ofthe keratome is depressed, and the keratome, directed parallel to the plane of the iris, is advanced into the anterior chamber for its full width, producing a 3.1 mm wide incision.
Fig. 2.
(Luntz) The sclera is incised with a Vannas scissors introduced into the scleral tunnel at each end, producing two radial incisions fashioned at each edge of the tunnel, producing a 3.1 mm wide lamellar scleral flap hinged at the limbus.
Fig. 3.
(Luntz) A Kelly punch is advanced to the anterior cut edge of the sclerocorneal bed and corneal scleral tissue is removed, producing a 2 mm X 2 mm trabeculectomy opening.
Fig. 4.
(Luntz) A 10-0 nylon suture is placed at each posterior comer of the lamellar scleral flap. The second bite is taken into the posterior lip of the scleral incision at the junction of the inner and middle third on either side; when the two sutures are tied, a scleral tunnel results.
Suturing the Lamellar Scleral Flap (5x suggested magnification)
A 10-0 nylon suture is placed at each posterior comer of the lamellar scleral flap. A bite is then taken in the posterior lip of the scleral incision at the junction of the outer and middle third of the incision on either side. When the two sutures are tied, each posterior comer of the lamellar scleral flap is moved slightly inward, and a scleral tunnel results (Figure 4).
Suturing the Conjunctival Flap (5x suggested magnification)
The fornix-based conjunctival flap is then anteriorly rotated and sutured to the sclera at the limbus with a continuous 10-0 nylon suture.
DISCUSSION This modified trabeculectomy has been performed in 19 eyes with open-angle glaucoma (Table 1). These eyes were followed for three months to one year (average 6.8 months). Preoperative intraocular pressure (lOP) ranged from 24 mm Hg to 42 mm Hg (average 36 mm Hg). Postoperatively, lOP ranged from 10 mm Hg to 18 mm Hg (average 14.3 mm Hg). No medication was required in eight eyes. In the remaining 11 eyes, fewer postoperative medications were needed. Complications in the 19 eyes evaluated have been minimal (hyphema in two eyes). There were no flat anterior chambers. These results are at least comparable to those
J CATARACT REFRACT SURG-VOL 20, MAY 1994
351
Table 1. Nineteen eyes with open-angle glaucoma.
Patient 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Intraocular Pressure (mm Hg) Follow-Up (Months) Preoperative Postoperative 4.2 42 18 37 24
14 16
39 38 42 31
12 13 10 15 17 14 11 17
29 41 25 38 40 39 35 32 42 29 41 36
18 15 15 13 12
14 12 16
6.0 10.0 5.4 3.0 12.0 3.2 9.4 8.4 12.0 6.1 4.0 4.0 8.4 10.2 6.0 5.2 7.5 4.5
obtained using the standard trabeculectomy technique originally described by Cairns. 1 REFERENCES 1. Cairns JE. Trabeculectomy-preliminary report of a new method. Am J Ophthalmol 1968; 66:673-679
352
2. Watson PG. Trabeculectomy. Dev Ophthalmol 1981; 1: 61-70 3. Freedman J, Shen E, Ahrens M. Trabeculectomy in a black American glaucoma population. Br J Ophthalmol 1976; 60:573-574 4. Galin MA, Boniuk V, Robbins RM. Surgical landmarks in trabecular surgery. Am J Ophthalmol 1975; 80:696701 5. Gressel MG, Heuer OK, Parrish RK II. Trabeculectomy in young patients. Ophthalmology 1984; 91:1242-1246 6. Kapetansky FM. Trabeculectomy or trabeculectomy plus tenectomy: a comparative study. Glaucoma 1980; 2:451453 7. Kimbrough RL, Stewart RH, Decker WL, Praeger TC. Trabeculectomy: square or triangular scleral flap. Ophthalmic Surg 1982; 13:753 8. Murray SB, Jay JL. Trabeculectomy: its role in the management of glaucoma. Trans Ophthalmol Soc UK 1979; 99:492-494 9. Nesterov AP, Egorov EA, Kolesnikova LN. Valve trabeculotomy and filtering iridocycloretraction in glaucoma. Doc Ophthalmol Proc Ser 1985; 43:253-257 10. Prasad VN, Narain M, Bist HK, Khan MM. Trepanotrabeculectomy (a combined operation for glaucoma). Indian J Ophthalmol 1984; 32:73-75 11. Scuderi G, Balestrazzi E, Recupero SM, Scorcia G. Modifications oftrabeculectomy. Glaucoma 1980; 2:500-506 12. Shin DH. Removable-suture closure of the lamellar scleral flap in trabeculectomy. Ann Ophthalmol1987; 19:51-53 13. Shuster JN, Krupin T, Kolker AE, Becker B. Limbus- v fornix-based conjunctival flap in trabeculectomy: a longterm randomized study. Arch Ophthalmol 1984; 102: 361-362 14. Sugar HS. Experimental trabeculectomy in glaucoma. Am J Ophthalmol 1961; 51:623-627 15. Luntz MH. Trabeculectomy using a fornix-based conjunctival flap and tightly sutured scleral flap. Ophthalmology·1980; 87:985-989
J CATARACT REFRACT SURG-VOL 20, MAY 1994
ABSTRACT A modified surgical technique is described for trabeculectomy using contemporary limbal incisional techniques for a simplified dissection of the lamellar scleral flap, a technically easier operation, with smoothly dissected surfaces. The results and complications are comparable to those using the standard method. Key Words: trabeculectomy, tunnel incision
The surgical technique for trabeculectomy has remained essentially unaltered since Cairns' first described it in 1968. 2- 14 The procedure is highly effective, but performing a perfect, smooth dissection of the lamellar scleral flap and lamellar scleral corneal bed is technically difficult. The modified method described here, which uses contemporary limbal incisional techniques, allows for a simplified dissection of the lamellar scleral flap and a technically easier operation with extremely smooth surfaces. The procedure is based on the tunnel incision used for cataract surgery with phacoem ulsification.
SURGICAL TECHNIQUE
Conjunctival Flap (5x suggested magnification)
A 5.0 mm wide, fornix-based conjunctival flap is raised at the limbus, preferably in the superonasal quadrant. The advantages of a fornix-based conjunctival flap for trabeculectomy, as previously documented, 15 are ( 1) the Tenon's fascia is minimally traumatized, (2) there is better exposure of the limbal area, and (3) thinning of the limbal conjunctiva and overhang of the cornea are avoided. With the conjunctival flap pushed posteriorly, hemostasis of the exposed sclera is obtained.
Tunnel Incision
(1 Ox suggested magnification) With a crescent knife (Alcon), an incision is made parallel to the limbus and 2.0 mm posterior to the limbus, extending for 3.0 mm in width. The incision is carried down to approximately one-third of the scleral thickness. The same crescent knife is introduced at the base of this incision and dissects anteriorly toward the limbus, extending into the cornea just anterior to the
vascular arcade and forming a transscleral and intracorneal pocket at about one-third scleral depth with a width of3.0 mm. A 3.1 mm keratome is introduced into the scleral pocket and advanced to its anterior edge immediately anterior to the limbal-corneal vessels. The point of the keratome is then depressed and the keratome directed parallel to the plane of the iris and advanced into the anterior chamber for its full width, producing a 3.1 mm wide incision. This maneuver completes the tunnel incision into the anterior chamber (Figure 1).
Lifting the Lamellar Scleral Flap (5x suggested magnification)
A radial incision is fashioned at each side of this tunnel with a Vannas scissors. One blade of the Vannas scissors is introduced into the scleral tunnel at each side; the other blade lies over the sclera. The sclera is then incised, with the blade moving anteriorly just to within the limbus in clear cornea. The two radial incisions fashioned at each edge of the tunnel complete a 3.1 mm wide lamellar scleral flap hinged at the limbus (Figure 2). This dissection produces a smooth inner surface for the lamellar scleral flap and the adjacent sclerocorneal bed.
The Trabeculectomy (1 Ox suggested magnification)
The lamellar scleral flap is raised, exposing the underlying sclerocorneal bed. A Kelly Descemet's punch is advanced to the anterior cut edge of the sclerocorneal bed, and corneoscleral tissue is removed until a 2.0 mm x 2.0 mm trabeculectomy opening is fashioned (Figure 3). The iris will generally herniate through tbis opening, and an iridectomy is performed, ensuring that the base of the iridectomy is wider than the trabeculectomy opening.
From the Manhattan Eye, Ear, and Throat Hospital and the Mount Sinai School of Medicine, New York, New York. Reprint requests to Maurice H. Luntz, M.D., 121 East 60th Street, New York, New York 10022. 350
J CATARACT REFRACT SURG-VOL 20, MAY 1994
Fig. l.
(Luntz) A 3.1 mm keratome is advanced into the scleral pocket. The point ofthe keratome is depressed, and the keratome, directed parallel to the plane of the iris, is advanced into the anterior chamber for its full width, producing a 3.1 mm wide incision.
Fig. 2.
(Luntz) The sclera is incised with a Vannas scissors introduced into the scleral tunnel at each end, producing two radial incisions fashioned at each edge of the tunnel, producing a 3.1 mm wide lamellar scleral flap hinged at the limbus.
Fig. 3.
(Luntz) A Kelly punch is advanced to the anterior cut edge of the sclerocorneal bed and corneal scleral tissue is removed, producing a 2 mm X 2 mm trabeculectomy opening.
Fig. 4.
(Luntz) A 10-0 nylon suture is placed at each posterior comer of the lamellar scleral flap. The second bite is taken into the posterior lip of the scleral incision at the junction of the inner and middle third on either side; when the two sutures are tied, a scleral tunnel results.
Suturing the Lamellar Scleral Flap (5x suggested magnification)
A 10-0 nylon suture is placed at each posterior comer of the lamellar scleral flap. A bite is then taken in the posterior lip of the scleral incision at the junction of the outer and middle third of the incision on either side. When the two sutures are tied, each posterior comer of the lamellar scleral flap is moved slightly inward, and a scleral tunnel results (Figure 4).
Suturing the Conjunctival Flap (5x suggested magnification)
The fornix-based conjunctival flap is then anteriorly rotated and sutured to the sclera at the limbus with a continuous 10-0 nylon suture.
DISCUSSION This modified trabeculectomy has been performed in 19 eyes with open-angle glaucoma (Table 1). These eyes were followed for three months to one year (average 6.8 months). Preoperative intraocular pressure (lOP) ranged from 24 mm Hg to 42 mm Hg (average 36 mm Hg). Postoperatively, lOP ranged from 10 mm Hg to 18 mm Hg (average 14.3 mm Hg). No medication was required in eight eyes. In the remaining 11 eyes, fewer postoperative medications were needed. Complications in the 19 eyes evaluated have been minimal (hyphema in two eyes). There were no flat anterior chambers. These results are at least comparable to those
J CATARACT REFRACT SURG-VOL 20, MAY 1994
351
Table 1. Nineteen eyes with open-angle glaucoma.
Patient 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Intraocular Pressure (mm Hg) Follow-Up (Months) Preoperative Postoperative 4.2 42 18 37 24
14 16
39 38 42 31
12 13 10 15 17 14 11 17
29 41 25 38 40 39 35 32 42 29 41 36
18 15 15 13 12
14 12 16
6.0 10.0 5.4 3.0 12.0 3.2 9.4 8.4 12.0 6.1 4.0 4.0 8.4 10.2 6.0 5.2 7.5 4.5
obtained using the standard trabeculectomy technique originally described by Cairns. 1 REFERENCES 1. Cairns JE. Trabeculectomy-preliminary report of a new method. Am J Ophthalmol 1968; 66:673-679
352
2. Watson PG. Trabeculectomy. Dev Ophthalmol 1981; 1: 61-70 3. Freedman J, Shen E, Ahrens M. Trabeculectomy in a black American glaucoma population. Br J Ophthalmol 1976; 60:573-574 4. Galin MA, Boniuk V, Robbins RM. Surgical landmarks in trabecular surgery. Am J Ophthalmol 1975; 80:696701 5. Gressel MG, Heuer OK, Parrish RK II. Trabeculectomy in young patients. Ophthalmology 1984; 91:1242-1246 6. Kapetansky FM. Trabeculectomy or trabeculectomy plus tenectomy: a comparative study. Glaucoma 1980; 2:451453 7. Kimbrough RL, Stewart RH, Decker WL, Praeger TC. Trabeculectomy: square or triangular scleral flap. Ophthalmic Surg 1982; 13:753 8. Murray SB, Jay JL. Trabeculectomy: its role in the management of glaucoma. Trans Ophthalmol Soc UK 1979; 99:492-494 9. Nesterov AP, Egorov EA, Kolesnikova LN. Valve trabeculotomy and filtering iridocycloretraction in glaucoma. Doc Ophthalmol Proc Ser 1985; 43:253-257 10. Prasad VN, Narain M, Bist HK, Khan MM. Trepanotrabeculectomy (a combined operation for glaucoma). Indian J Ophthalmol 1984; 32:73-75 11. Scuderi G, Balestrazzi E, Recupero SM, Scorcia G. Modifications oftrabeculectomy. Glaucoma 1980; 2:500-506 12. Shin DH. Removable-suture closure of the lamellar scleral flap in trabeculectomy. Ann Ophthalmol1987; 19:51-53 13. Shuster JN, Krupin T, Kolker AE, Becker B. Limbus- v fornix-based conjunctival flap in trabeculectomy: a longterm randomized study. Arch Ophthalmol 1984; 102: 361-362 14. Sugar HS. Experimental trabeculectomy in glaucoma. Am J Ophthalmol 1961; 51:623-627 15. Luntz MH. Trabeculectomy using a fornix-based conjunctival flap and tightly sutured scleral flap. Ophthalmology·1980; 87:985-989
J CATARACT REFRACT SURG-VOL 20, MAY 1994