Of all sutures used in eye-related surgeries, from a soft tissue approximation in the lids to the anchoring of intraocular lenses, Prolene, and Vicryl remained everyone’s favorite. The absorbable polyglycolic acid-derived monofilaments (Vicryl) holds its tensile strength for at least 2-3 weeks. It runs the show in major oculoplastic, orbital, and ocular surface surgeries. On the other hand, polypropylene (prolene) sutures incite negligible tissue reaction and its durability has the advantage of using it as a permanent anchoring suture for implants like intraocular lenses.
Polytetrafluoroethylene (ePTFE) derived Gore-tex suture is very unique and extensively used in cardiovascular surgeries. The idea of a 1:1 ‘needle to thread’ ratio which completely fills the needle hole, thus minimizing leakage makes it a good choice for vascular anastomosis. (whereas the conventional polyprolene suture has a 3:1 ratio design) What makes it more fascinating is its porous microstructure despite it being a monofilament. The thread is approximately 50% air by volume and in an adequately tensioned knot, the air is forced completely out of the suture securing the knot and with a good knot memory. Apart from conventional qualities of any non-absorbable suture like biocompatibility, minimal tissue reaction, and higher tensile strength, Gore-tex stands above in visibility and easy handling.
Manufacturers provide coding for different thread sizes, thread lengths, needlepoint, and needle-to-thread ratios. In ophthalmology CV-8 TTc-13 has been used extensively for scleral fixation of intraocular lenses with the idea of easy handling and long-lasting sutures. The code CV-8 is the thread size corresponding to the USP size of 7-0. (For sutured SFIOL surgeries, we routinely use 9-0 or 10-0 double-armed polyprolene sutures). This is the smallest size available in the gore-tex catalog. “T” refers to the taper point of the needle and additional “T” refers to a 3/8 circle design and the letter “c” refers to ‘C’ series premium needle. Usually, the thread length is around 76cm and the needle is around 13mm.
Gore-tex has its flaws as well which includes the difficulty in burying the bulky knot in the sclera, its subconjunctival location may lead to suture exposure. Also, the lack of long-term data in ophthalmic use compared to time-tested prolene and the higher cost restricts many surgeons from using it. There seems to have a huge scope to expand its utility in oculoplasty and orbital surgeries as well. Let’s embrace the fact that we have add-on suture now in ophthalmic practice to produce the best surgical results. At this juncture, Gore-tex stands first if one is aware of its limitations and advantages.
Authors
Dr. Steffi Rose Prasad,
Dr. Nagesha C K