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Single-pass four-throw technique a new option for pupilloplasty
A helical configuration inside the eye prevents the suture from opening up.
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Various techniques have been described for pupil reconstruction, and single-pass four-throw, or SFT, is one of the newer techniques that can be employed for pupilloplasty. As the name suggests, a single pass of a 10-0 suture on a long arm needle is passed through the iris tissue followed by creation of a loop with four throws around it that slides inside the eye. This creates a helical configuration that prevents the suture from opening up.
A knot essentially consists of an initial approximating loop followed by a second throw of sutures that creates a securing loop. The SFT technique employs the creation of only the initial approximating loop, but it comprises four throws, thereby creating an intertwining of sutures that has a self-locking mechanism and prevents loosening of the suture loop.
Technique
Two side-port incisions are created on opposite sides along the line of iris defect that is to be repaired. A single-arm 10-0 polypropylene suture threaded on a long arm needle is introduced from the incision in a way that engages the proximal part of the iris defect (Figure 1) that needs to be corrected. A 26-gauge needle is introduced from the opposite end and is passed so that it engages the distal part of the iris defect (Figure 2) that needs to be approximated. End-opening forceps are introduced and used to grab the edge of the iris defect so that the 26-gauge needle can pass through it easily (Figures 1 and 2).
Figure 1. The proximal end of the iris leaflet is held with end-opening forceps, and a 10-0 long arm needle is passed through it from the side-port incision.
Figure 2. A 26-gauge needle is passed through the opposite side, and it passes from the distal edge of the iris tissue.
Images: Narang P, Agarwal A
Figure 3. The long arm needle is passed into the barrel of the 26-gauge needle and is pulled out of the eye.
Figure 4. A Sinskey hook is passed, and it engages the suture that is pulled inside the anterior chamber, creating a loop.
Figure 5. The loop is pulled out, and the suture end is passed four times through the loop.
Figure 6. Both ends of the suture are pulled, and this leads to the sliding of the loops inside the anterior chamber. After the loops are secured, the suture is cut in a way that it leaves 1 mm on either side.
The tip of the long arm needle is then passed into the barrel of the 26-gauge needle that is then withdrawn from the eye, thereby pulling the needle and the suture along with it (Figure 3). A Sinskey hook is introduced from the side-port incision, a loop is created (Figure 4) and pulled out, and the cut end of the suture is passed four times through the loop (Figure 5). Both ends of the suture are pulled, and as it is done, the loops slip inside the eye, as in a modified Siepser technique. This creates an intertwining, interlocking mechanism that secures the loop and prevents it from opening. Micro-scissors are then introduced into the anterior chamber, and the sutures are cut, leaving behind a bud of 1 mm on either side of the loop (Figure 6).
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, is director of Dr. Agarwal’s Eye Hospital and Eye Research Centre. Agarwal is the author of several books published by SLACK Incorporated, publisher of Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at 19 Cathedral Road, Chennai 600 086, India; email: dragarwal@vsnl.com; website: www.dragarwal.com.
- Priya Narang, MS, is the director of Narang Eye Care & Laser Centre, Ahmedabad, India. She can be reached at email: narangpriya19@gmail.com.
Disclosure: The authors report no relevant financial disclosures.