Reverse four-throw pupilloplasty allows knot formation on posterior surface of iris
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In this column, we will describe a simple and novel method of performing a pupilloplasty procedure that allows adequate pupil reconstruction.
The technique of reverse four-throw (RFT) pupilloplasty works on the principle of formulating four throws, which allows a self-sealing and self-locking knot to form as in the single-pass four-throw technique of pupilloplasty. RFT pupilloplasty allows knot formation on the posterior surface of the iris, unlike other techniques that have the knot lying on the anterior iris surface with the suture ends protruding in the anterior chamber.
Source: Rhea Narang, Priya Narang, MS, and Amar Agarwal, MS, FRCS, FRCOphth
Technique
Two paracentesis incisions are made: one at the distal end and another midway between the proximal and distal iris defect. The placement of the incision depends on the surgeon’s preference.
End-opening forceps introduced from the proximal paracentesis incision hold the proximal iris defect. A 9-0 polypropylene suture on a long arm needle is introduced, engaging the proximal iris from the posterior surface to emerge on the anterior surface of the iris. Meanwhile, a 27- or 30-gauge needle is introduced from the distal paracentesis incision, and it pierces the distal defect from the posterior side to emerge on the anterior surface of the iris (Figures 1a to 1d). The suture needle is threaded into the barrel of the needle and eventually pulled out of the anterior chamber.
A Sinskey hook is passed through the distal paracentesis, and the suture loop is withdrawn. The suture end is passed through the loop four times (in the same direction), and both suture ends are pulled (Figures 2a to 2d). The suture knot eventually slides inside the anterior chamber approximating the iris defect, with a difference that the knot lies on the posterior surface of the iris. The suture ends are cut with end-opening scissors.
Discussion
This technique could be especially beneficial for cases scheduled for endothelial keratoplasty. Absence of suture knots and tails in the anterior chamber can be helpful as the endothelial graft typically lands in the center of the pupil that harbors the suture knots and tails, which can potentially harm the endothelial cells of the donor graft. During the process of graft unrolling, the anterior chamber is kept shallow. At this stage, further manipulation can debride the endothelial cells as the suture knots and tails can rub against the graft. The suture knot in RFT is not detected on anterior segment OCT, and the iris plane is depicted as a flat surface.
- References:
- Narang P, et al. Eur J Ophthalmol. 2017;doi:10.5301/ejo.5000922.
- Narang R, et al. Eur J Ophthalmol. 2023;doi:10.1177/11206721231165452.
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, director of Dr. Agarwal’s Eye Hospital and Eye Research Centre, is the author of several books published by SLACK Books, sister company of Healio publisher 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 aehl19c@gmail.com; website: www.dragarwal.com.
- Priya Narang, MS, of Narang Eye Care & Laser Centre, Ahmedabad, India, can be reached at narangpriya19@gmail.com.
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