|Year : 1993 | Volume
| Issue : 2 | Page : 81-82
Releasable suture technique for trabeculectomy
Pushpa Jacob, Ravi Thomas, Anuradha Mahajan, Annie Mathai, Stephen C Gieser, Renu Raju
Schell Eye Hospital, Christian Medical College, Vellore, Tamil Nadu, India
Schell Eye Hospital, Vellore 632 001, Tamil Nadu
Source of Support: None, Conflict of Interest: None
We studied the effect of the releasable suture technique on immediate postoperative intraocular pressure (IOP). Nine eyes of nine patients with glaucoma had trabeculectomy with a releasable suture. In the six eyes that did not receive antimitotics, the suture was released by the fifth postoperative day; in the others suture release was delayed up to the fourteenth day. Of the nine patients, one had an acceptable postoperative IOP and did not need suture release; in another the suture broke and could not be released. In the remaining seven patients, the difference between the pre-release and post-release IOP was statistically significant (p < 0.001). The complications of this technique include failed suture release, subconjunctival hematoma and a distinctive "windshield wiper" keratopathy.
Keywords: Trabeculectomy, release suture, intraocular pressure
|How to cite this article:|
Jacob P, Thomas R, Mahajan A, Mathai A, Gieser SC, Raju R. Releasable suture technique for trabeculectomy. Indian J Ophthalmol 1993;41:81-2
|How to cite this URL:|
Jacob P, Thomas R, Mahajan A, Mathai A, Gieser SC, Raju R. Releasable suture technique for trabeculectomy. Indian J Ophthalmol [serial online] 1993 [cited 2020 Nov 24];41:81-2. Available from: https://www.ijo.in/text.asp?1993/41/2/81/25617
Titration of postoperative filtration following trabeculectomy can be achieved by various means. While shell tamponade with full thickness filtration is outmoded and the methods such as digital massage are still used, the recent emphasis has been on post operative argon laser suturolysis.  This method, though effective, requires access to an argon laser, a special lens, and compression of the filtration area soon after operation. Furthermore, failure of laser suturolysis , remains a possibility. The releasable suture technique has been described by various authors as an alternative to laser suturolysis. 2 This technique is advantageous because it is easy and does not depend on the availability of sophisticated equipment. Additionally, laser suturolysis may be unsuccessful if there is a thick overlying Tenon's capsule, postoperative inflammation, edema, or subconjunctival haemorrhage.
This study was designed to determine whether releasable sutures could reliably lower intraocular pressure in the immediate postoperative period.
| Materials and methods|| |
Nine eyes of nine patients with advanced glaucoma were selected to undergo trabeculectomy with a releasable suture. The target intraocular pressure was fixed below 15mm Hg in each patient. The technique we used is a modification of the method described by Cohen.  A Cairns-type trabeculectomy with a fornix based conjunctival flap was performed in the usual manner.  A 10-0 monofilament nylon suture was passed intra stromally through the cornea, onto the scleral flap, and looped out. A standard scleral flap suture was then taken. The suture end [Figure - 1], suture "a") was tied to the loop [Figure - 1]. loop "b") with four throws to form a slip knot. The corneal end was trimmed to about 3mm and the trabeculectomy was completed. To release the suture, the corneal end was grasped with a forceps and pulled gently.
Antimitotics were used in six of the nine patients. In patients that did not receive antimitotics, the suture was released by the fifth postoperative day. In the others, the release was delayed up to the fourteenth dav. We assumed that like laser suturolvsis,  release of the suture after the fourth week did not produce any significant effect. Of the nine patients, one patient had an acceptable IOP and there was no need to release the suture. In another, the suture broke and so could not be released.
| Results|| |
[Figure - 2][Figure - 3] show the pre-release and the postrelease intraocular pressure. This drop was statistically highly significant (p < 0.001).
We had one case of failed suture release. In this case subsequent laser suturolysis successfully lowered the TOP. In one paient, a small subconjunctival hematoma appeared at the suture site after release in one patient but resolved without short term detrimental effect. None of the eyes developed shallow or flat anterior chamber. A distinctive wedge-shaped epithelial defect which resembles the pattern left on the windscreen by the wiper blade occurred in three patients [Figure - 4]. We coined the term "windshield wiper keratopathy"  for this characteristic complication. Only one of the three patients with this complication was treated with antimitotics.
| Discussion|| |
The releasable suture technique for trabeculectomy is advantageous because it is easy and does not depend on the availability of sophisticated equipment. Additionally laser suturolvsis may be unsuccessful in specific instances.
The TOP in all patients was successfully lowered after removing the releasable suture. Despite the small sample size in our study, the difference in TOP before and after release of the suture was so large that statistical significance was very high (p < 0.001) using analysis by the paired t-test. The drop in TOP following suture release was clinically significant since the target pressure was achieved (at least temporarily), in all cases, and the bleb increased in size.
The most frequent complication encountered was 'windshield wiper keratopathy'. It occurs due to the rubbing of the suture on the cornea with the movement of the lids. This complication occurred in three patients. As only one of the three patients was treated with antimitotics, it seemed to occur irrespective of their use. Although we did not encounter any residual, the occurrence of such a keratopathy with the concurrent use of antimitotics would seem alarming.
In our prospective study, the releasable suture technique effectively titrated postoperative filtration. We found that expensive instrumentation was not required and the complications encountered were minimal. Care should be exercised if antimitotics are used concurrently. We suggest releasable sutures as a satisfactory alternative to laser suturolysis.
| References|| |
Savage JA, Condon GP, Lvtle RA and Simmons RJ. Laser suturolysis after trabeculectomv_ , Ophthalmology 95: 1631-1637, 1988.
Wilson RP. Techinical advances in filtration surgery. In McAllister JA, Wilson RP. (eds). Glaucoma. Butterworths,243, 1986.
Cohen JS and Osher RH Releasable scleral flap suture. Ophthalmol. Clin. North America. 1: 187-197, 1988.
Cairns JE. Trabeculectomv. preliminary report of a new procedure. Am J Ophthalmol. 66: 673-679, 1968.
Thomas R, Sen S, Mahajan A and Gieser SC. Windshield wiper keratopathy. A complication of releasable suture technique for trabeculectomv. Submitted: Aust NZJ Ophthalmol.
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]