Placement of “silicone oil retention sutures” sulcus to sulcus in the iris plane in a variety of geometric patterns provides an effective method for keeping the oil out of the anterior chamber.
Take-home message: Placement of “silicone oil retention sutures” sulcus to sulcus in the iris plane in a variety of geometric patterns provides an effective method for keeping the oil out of the anterior chamber.
Reviewed by Ronald C. Gentile, MD
New York-Silicone oil is commonly used as a long-term intraocular tamponade, and can be a retina specialist’s best friend. In eyes with retinal injury secondary to severe trauma with associated iris loss, however, the use of silicone oil can become surgeon’s worst enemy, said Ronald C. Gentile, MD.
In aphakic eyes with iris loss, placement of 10-0 polypropylene (Prolene, Ethicon) sutures across the anterior chamber from sulcus to sulcus, simulating the iris diaphragm, is an effective method for preventing silicone oil from entering the anterior chamber, said Dr. Gentile, professor of ophthalmology, Icahn School of Medicine at Mount Sinai, and director of the Ocular Trauma Service (posterior segment) and surgeon director, The New York Eye and Ear Infirmary, New York.
Dr. Gentile and Dean Eliott, MD, first described the technique for creating these “silicone oil retention sutures” and its success in a paper [Arch Ophthalmol. 2010;128:1596-1599]. The report presented three cases and used high-frequency ultrasound biomicroscopy to document the ability of the sutures to prevent silicone oil-corneal touch.
To watch procedure, click here.
Evolving suture patterns
The sutures in the initial cases were passed to create a square pattern. The technique has been adopted by others [Arch Ophthalmol. 2012;130:1231-1232], and over time, the created shape has evolved to include a triangle, “H”, trapezoid, and star, which is configured by creating two interlocking triangles.
The technique has been used in eyes with marked and complete iris loss and as a method for retaining an artificial iris-IOL complex, as described by Dr. Gentile, Vittorio De Grande, MD, Ken Rosenthal, MD, and Michele Reibaldi, MD [J Cataract Refract Surg. 2012;38:2045-2048].
Choosing a specific suture pattern depends on the clinical scenario and the surgeon’s preference. Drs. Gentile and Eliott have found the triangular pattern to be most surgically efficient by providing the greatest suture surface area with the least number of needle passes. Retention sutures usually are placed before the silicone oil is injected-just before a fluid-air, perfluorooctane (PFO)-air, or PFO-silicone oil exchange.
“Placement of polypropylene sutures in the iris plane in eyes with partial or total aniridia creates an effective barrier between the oil and aqueous humor,” Dr. Gentile said. “It thereby keeps the silicone oil away from the trabecular meshwork and cornea to prevent the development of glaucoma and keratopathy.”
Silicone oil retention sutures have been adopted by other surgeons. Besides the triangle, created shape also has evolved to include “H”, trapezoid, and a star (above). The star shape is configured by creating two interlocking triangles. (Photo courtesy of Ronald C. Gentile, MD)The suturing is performed using 10-0 polypropylene suture on a 16 mm STC-6 needle (Ethicon). To create the square pattern, the needle is inserted 1 mm posterior to the limbus, passed across the anterior chamber, and retrieved on the opposite side using a short, 5/8-inch, 25-gauge needle attached to a 1-mL syringe.
Each side of the square is created by passing the suture across twice. The second pass being parallel and 1 mm away from the first. The knot is rotated through the 25-gauge suture tract, and the external suture is covered with conjunctiva.
To create the triangular pattern, a double-armed suture is used. Starting superiorly at the apex, the first suture is placed from 12:15 to 7:45. Using the other needle, the next suture is passed from 11:45 to 4:15, and it is then taken back through, entering at 3:45 position and exiting at 8:15 position. The two suture arms are centered and tied at the 8:00 position, and the knot is rotated through the 25-gauge needle tract.
Genesis and mechanism
The idea for using sutures to retain silicone oil in the posterior segment in aphakic eyes with iris loss was based on Dr. Gentile’s observation of an eye in which silicone oil was held back by a fibrin strand across the pupil.
“I reasoned, if a fibrin strand can act on the silicone oil aqueous interface and prevent the oil from, entering the anterior chamber, why not a 10-0 polypropylene suture,” Dr. Gentile said.
The efficacy of this procedure is explained by the fact that the surface tension of silicone oil in water, 50 erg/cm2, is relatively high, and the force needed for the sutures to disrupt the silicone oil aqueous interface exceeds the buoyant force of the oil in aqueous, even in the supine position.
“Because use of silicone oil retention sutures depends on an intact silicone-oil interface,” Dr. Gentile added, “its success requires the presence of sufficient aqueous production and that surgeons avoid overfilling the eye with silicone oil.”
Ronald C. Gentile, MD
This article was adapted from Dr. Gentile’s presentation at Retina Subspecialty Day during the 2015 meeting of the American Academy of Ophthalmology. Dr. Gentile has no relevant financial interests to disclose.