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Year : 1982  |  Volume : 30  |  Issue : 2  |  Page : 99-101

Revision of trepano-trabeculectomy

Department of Ophthalmology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
D N Gangwar
Department of Ophthalmology, Postgraduate Institute of Medical Education & Research, Chandigarh
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Source of Support: None, Conflict of Interest: None

PMID: 7141602

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How to cite this article:
Gangwar D N, Bansal S L, Jain I S, Murthy G V. Revision of trepano-trabeculectomy. Indian J Ophthalmol 1982;30:99-101

How to cite this URL:
Gangwar D N, Bansal S L, Jain I S, Murthy G V. Revision of trepano-trabeculectomy. Indian J Ophthalmol [serial online] 1982 [cited 2021 Jun 24];30:99-101. Available from: https://www.ijo.in/text.asp?1982/30/2/99/28087

With the presently available filtering procedures, a satisfactory intraocular pressure control can be expected in 60%-85% of eyes[1]. In case of trabeculectomy, this percentage rises to 90% because it provides a uniformly sustained pressure control and the flat and diffuse bleb lies about five millimeters behind the limbus[2]. The causes of failure of filtering procedures have been discussed by Maumenee[3] but sub-scleral surgery singles out in this respect because of additional scleral flap complications are likely to occur.

Recently we observed two cases of failure of trepano-trabeculectomy because of scleral flap problems which could be dealt wit' successfully by revision surgery.

  Case reports Top

Case No. 1

45 M, presented to us with recurrent episodes of pain, redness and watering in right eye since last two months & left eye for 5 years with the result that he had lost all vision in left eye.

Examination revealed an accurate light projection RE and defective projection LE. The right eye had lid oedema, moderate ciliary congestion, central irregular epithelial defect in cornea with diffuse haze so that no details of anterior chamber could be made out..

Biomicroscopy showed pigment clumps on the back of cornea, posterior synechiae all along the pupillary margin and pigment deposits on anterior lens surface. Corneal sensitivity was markedly diminished and it showed four con­fluent staining spots with fluorescein.

Digital tonometry gave an impression of + + tension. Left eye was quiet with vascularised corneal leucoma, irregular anterior chamber and high intraocular pre­ssure. He was diagnosed as having herpetic kerateo-uveitis with secondary bacterial infection and glaucoma, the right eye being active. Accordingly he was given sub­conjunctival myricin 0.2 ml. RE and was put on G. Homatropine thrice daily and G. Chloramphenicol 1 % two hourly. Systemi­cally administered tablet Diamox six hourly could not control intra-ocular pressure and a paracentesis was done which also failed. The intra-ocular pressure at this stage was 24 mm Hg. with tablet Diamox given eight hourly along with potassium supplements. The corneal lesion had healed.

A trepano-trabeculectomy RE using 1.5 mm trephine was done along with synechia lysis and complete iridectomy. He had a mild operative hyphaema which absor­bed spontaneously. Otherwise post-operative period was uneventful. The intra-ocular pressure remained controlled and the bleb functioned well till one month. Thereafter, he was found to have an intraocular pressure of 29 mm of Hg with bleb still functioning and by 2 months the pressure rose to 41 mm Hg.

At this stage, an exploration of the operative site was undertaken. The conjunctival flap could be re-dissected with minimal effort but it was found that the scleral flap was bound down to its bed all over. It was re-dissected through the original plane only to find a patent trephine hole. The deep, surface of scleral flap and its bed were made smooth with a Bard-Parker knife and the flap was resutured in its place slightly loosely with two 10.0 monofilament sutures. Post- operatively, he had a shallow anterior chamber for which an air injection was sufficient. After this, the patient has been maintaining normal intraocular pressure and an accurate projec­tion of light.

Case 2

44 M, presented with a corneal ulcer LE of five months duration. At the time of presentation, the corneal ulcer was already perforated but he had an accurate light projection. The right eye was lost in childhood trauma.

A lower half conjunctival flap was given to the left eye to support the cornea. This took care of the ulcer but he was found to have secondary glaucoma and was put on tablet Diamox eight hourly. This could not control his intraocular pressure (59 mm of Hg) and the eye was subjected to a trepano-trabeculectomy with a 1.5 mm trephine along with a complete iridectomy. Post- operatively he was all well with controlled pressure and a visual acuity of HM close to face and a good, functioning bleb for 6 months. When he was found to have an intraocular pressure of 41 mm of Hg and absent bleb. Resurgery done, revealed a scleral flap densely adherent to its bed. As soon as these adhesions were dissected away, aqueous flowed out in the form of a gush. The trephine opening itself was patent. The scleral flap was resutured in place with two 10-0 sutures given slightly loosely and the conjun­ctiva closed. Since then he has maintained an intra-ocular pressure within normal limits and an accurate projection of light. He has a flat and diffuse bleb.

  Discussion Top

Maumenee[3] has classified the causes of failure of filtering operations into intra-ocular, scleral and extra-scleral. The scleral causes of failure may result from the inadequacy of scleral opening due to retention of Descemet's membrane or scleral tissue. This would con­veniently apply to Scheie's thermosclerostomy. Depending upon the appearance of the filtering bleb and its functional status, bleb surgery has been advocated by McCulloch[4] and Cohen et a1[5]. The latter group of workers goes further in advising the enlargement of previous sclerostomy site in under filtering eyes

The scleral causes of under filtration in case of sub-scleral procedures like trabeculectomy, trepano-trabeculectomy and subscleral Scheie's cautery have not been properly attended to previously. In addition to inade­quacy of scleral opening, there may be scarring of scleral flap to its bed. To antici­pate this, Kottow[6] devised trabeculectomy with a scleral wick, the total evaluation of this procedure is under way.

Our two cases were advanced post-inflam­matory glaucomas. The intra-ocular pressure could not be controlled with carbonic anhydrase inhibitors and hence they were subjected to trepano-trabeculectomy. This procedure controlled the glaucoma for a time. Neither of the two cases had significant post­operative inflammation. With the passage of time, the development of adhesions led to complete plastering of scleral flap to its bed. These scleral flaps could be raised again and the trephine openings were found patent. A relatively loose suturing of the scleral flap maintained the bleb after revision surgery. Both the cases are behaving well. Such an exploratory procedure in a failing filtration appears advisable.

The success rate of trepano-trabeculectomy in secondary glaucomas is around 60%7. And here we have seen two failures occurring in post-inflammatory glaucomas. It seems that scarring in the scleral flap-bed interface is more likely in such cases. Sugars advises the use of topical steroids when the belb starts to shrink and fibrose. This may well be applicable to sub-scleral procedures.

In passing it may be said that the present two cases confirm that drainage in trabecule­ctomy is subconjunctival and not through the cut ends of Schlemm's canal. Otherwise the closure of the flap bed interface with a patent trephine opening in sclera would not have led to failures. Likewise, the finding of patent scleral holes made by 1.5 mm trephine inspite of flap-bed adhesion suggests that this size of trephine is not smaller, rather it is adequate.

  Summary Top

Two cases of failed trepano-trabeculectomy in postinflammatory glaucomas are reported. Revision surgery consisting of re-raising of scleral flap at the initial site of surgery has controlled the tension. The cleavage between the scleral flap and its bed due to original surgery was barely perceptible. The trephine hole in both the cases was patent and needed no alteration. Consideration of such a revision surgery for failing sub-scleral filtering pro­cedures is recommended.[8]

  References Top

Kolker, A.E. and Hetherington, J. Jr., 1970, Diagnosis and Therapy of Glaucomas 3rd Ed. P. 356. The C.V. Mosby Company, Saint Louis.  Back to cited text no. 1
Elkington, A.R., 1975, Recent Advances in Ophthalmology No. 5, P. 83, Churchill Livingstone. New York.  Back to cited text no. 2
Maumence. A.E., 1960, Trans. Amer. Ophthal­mol. Soc. 58 : 319.  Back to cited text no. 3
McCulloch, L., 1967, Int. Ophthalmol. Clin., 7 (1): 125.  Back to cited text no. 4
Cohen, J.S., Shaffer, R.N ; Hethrington, J. Jr. and Hoskins, D., 1977, Arch. Ophthalmol. 95 : 1612.  Back to cited text no. 5
Kottow, M. H., 1979, Ophthalmologica, 179 99.  Back to cited text no. 6
Cvet Kovic. D., Blagojevic, M. and Dodic. V., 1978, Acta.Ophthalmol. 56:150.  Back to cited text no. 7
Sugar H.S., Amer J. Ophthalmol 59 :854.  Back to cited text no. 8


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