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Editors Selection IGR 13-2
Surgical Treatment: Adjustable sutures versus laser suturelysis
Comment by Paul Schacknow on:
46035 A comparison of the intraocular pressure lowering effect of adjustable suture versus laser suture lysis for trabeculectomy, Kobayashi H; Kobayashi K, Journal of Glaucoma, 2011; 20: 228-233
Intra-operative and post-surgical wound manipulation techniques have been developed to both lower IOP as well as to minimize the complications caused by overfiltration after trabeculectomy surgery for glaucoma. Kobayashi et al. (1000) report on a prospective clinical trial where 50 Japanese patients with POAG with IOP of ≥ 22 mmHg on medical therapy were randomized to undergo trabeculectomy performed by a single surgeon using two different scleral flap suturing techniques. All patients had fornix-based conjunctival flaps supplemented with mitomycin C (0.04% soaked sponges were placed under the flap for 3 min, followed by irrigation with 250 mL of balanced salt solution.). All eyes had the 4 x 4 mm scleral flap closed with two 3-1-1 corner sutures of 10-0 nylon, then the three sides of the flap were closed with either 4-loop 'adjustable sutures' of 10-0 nylon, or 3-1-1 'standard' 10-0 nylon sutures. Twenty-five eyes were randomly assigned to each group. All glaucoma medications were discontinued after surgery. Patients received postoperative antibiotic and steroid drops which were tapered and discontinued after three months. If the bleb was flat or the IOP was not low enough, the operated eyes first underwent ocular massage, followed by either loosening of the adjustable sutures with forceps in the 'adjustable suture' group, or laser suture lysis for the group with 'standard sutures'. Patients were followed for 12 months unless their IOPs were > 21 mmHg on two consecutive visits and unresponsive to suture manipulation and thus requiring glaucoma medication or further surgery.
As reported, no significant difference was found in patient demographic characteristics or baseline IOPs for the two groups or the difference in mean IOP between the two groups at any visit (three, six, 12 months). At 12 months, in the adjustable suture group, 96% of the eyes achieved IOPs ≤20 mmHg and 88% IOP ≤16 mmHg. In the laser lysis standard suture group 92% had IOPs ≤20 mmHg and 84% IOP ≤16 mmHg. These differences in achieved IOPs between the groups were not statistically significant.
Placing and manipulating adjustable sutures is more complex than tying and subsequent laser lysis of standard sutures
Most importantly, none of the eyes with adjustable sutures manipulated by forceps exhibited flat/shallow anterior chambers, whereas 24% of the eyes which underwent laser suture lysis did have this complication. The authors speculate that the more gradual reduction in IOP achievable by manipulating adjustable sutures is less likely to rapidly shallow the anterior chamber, as compared to the sudden reduction in IOP caused by laser suture lysis. They also feel that laser suture lysis can cause inadvertent conjunctival burning and scarring perhaps resulting in a compromised bleb.
Placing and manipulating adjustable sutures is more complex than tying and subsequent laser lysis of standard sutures thus less likely to be done by comprehensive ophthalmologists vs. glaucoma specialists. Forceps manipulation of sutures post-operatively increases the risk of infection. Nonetheless with this relatively small series of patients the authors have demonstrated the utility of adjustable trabeculectomy sutures in minimizing hypotony and flat anterior chambers.
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