A New Way to Close Clear-Corneal or Limbal Incisions

This reversed needle pass uses the three-throw adjustable knot.

JULIO NARVÁEZ, MD

In the traditional technique for placing a single radial suture for a non-sealing corneal or limbal incision, the needle enters on the corneal side of the limbal incision and exits toward the scleral side, and the suture is tied with a 3-1-1 surgical knot. Here, I present an improved suturing technique that reverses the needle path. The needle enters on the scleral side of the limbal incision, exits on the corneal side toward the apex, and is tied with an adjustable 1-1-1 knot.¹

Self-sealing clear-corneal incisions have become the most common incision type for cataract and other anterior segment surgeries.² Failure of the corneal incision to seal raises the risk for endophthalmitis.³ When the incision fails to seal after stromal hydration, a suture is required. The most common method of suturing is passing the needle from the corneal apex side of the incision and aiming it toward the scleral side (Figures A, B). The suture is then tightened and tied, most often with a 3-1-1 knot.

Figures 1 – 4. The first throw is wrapped as in the traditional 3-1-1 technique but with one loop instead of 3.

Figures A, B. In the traditional approach the needle with the suture passes through the wound from corneal to the scleral side (A). In our modified approach, the needle enters on the scleral side (B).

Problems With Traditional Approach

However, this traditional suturing method has inherent problems. Inaccurate suture tension may result from the technique. The 3-1-1 knot is not adjustable and can cause over- or under-tightening of the suture, which induces excessive astigmatism or requires replacement. The knot is large and can break during burial. Anterior chamber shallowing or collapse often occurs because, as the needle penetrates the roof of the corneal incision, it pushes on and opens the inner lip of the leaking but often partially sealed incision. Loss of aqueous humor then ensues.

In routine cataract surgery, the ideal technique achieves two goals:

• Avoids anterior chamber collapse while suturing to prevent anterior IOL vaulting with possible dislodgement of the optic anterior to the capsule rim.

• Prevents endothelial trauma that occurs when the chamber collapses completely.

Figure C. Detail showing the primary knots the reversed needle path employs.

The technique for suturing non-sealing clear-corneal or limbal incisions I present prevents these potential problems, is more efficient for surgeons and creates a much smaller, easier to bury knot.

The Three-Throw Technique

A 10-0 nylon suture enters at the periphery of the cornea beyond the base of the incision on the scleral side and exits on the corneal side toward the apex. The reversed-needle pass travels from the bottom of the inner lip of the incision and apposes the lip to the roof of the incision, allowing the wound to maintain partial closure to avoid collapse of the anterior chamber.

An adjustable 1-1-1 knot then ties off the suture. Creating the adjustable knot is a simple: Tie a granny knot that slides and then lock it with a square knot (Figure C). This can be accomplished in a variety of ways; we present one. The first two throws of the knot are done with single loops creating a granny knot which is adjustable and optimizes tension. The third throw creates a square knot, wrapping the suture in the opposite direction to lock the knot securely (Figures 1 to 11).

Figures 5 – 8. The second throw is wrapped around the needle holder in the opposite direction of the traditional 3-1-1, creating a granny knot (or a cow hitch), instead of a square locking knot. After the second throw, the tension in the resulting granny knot is adjustable.

Advantages of 1-1-1 Knot

Tying a suture with a 1-1-1 adjustable knot is not a new technique, but has been underused in ophthalmology.^4-6 To our knowledge, no author has described the application of this adjustable knot to corneal or limbal incisions combined with passing the needle in the reverse direction. The two significant differences between this technique and the traditional technique for suturing corneal and limbal incisions are the reversed-needle path and the adjustable square knot, both of which provide important advantages.

Figures 9 – 11. The final throw is wrapped in the usual manner to create a square knot and lock the 1-1-1 adjustable knot into place. The knot is complete. The tails of the knot may now be trimmed, and the suture buried.

Tying the suture is especially important because the knot tension seals the incision while preventing excessive induced astigmatism from an overly tight suture.⁷ The 1-1-1 knot has three advantages over the traditional 3-1-1 knot:

• On the second throw, the 1-1-1 knot is easy to adjust so the suture tension does not induce excessive astigmatism. Once the third throw locks the knot, studies have shown, it has excellent resistance to breaking and slipping.⁸

• The knot can be tied more quickly than the traditional knot because it requires only three loops instead of five with the 3-1-1 knot.

• The knot is smaller, so it is considerably easier to bury and less likely to break when rotated.

Corneal Laceration Repair

The advantages of the 1-1-1 knot are significant in corneal laceration repair. Edema results when the exposed stroma of the wound absorbs aqueous humor or tears, or both. During repair, the first suture placed often loosens with time as the apposed tissue becomes less edematous and the suture has to be replaced.

Moreover, burying knots in weakened lacerated tissues can be difficult, not infrequently causing breakage. Leaving the 1-1-1 knot untied after the second adjustable throw allows further tightening later on, when the endothelium reduces corneal edema. The smaller knot is easier to bury, preventing broken sutures, which when replaced, may increase suture track leaks.

Advantages of Reversed Needle Pass

The reversed needle-pass suture technique also has two significant advantages over the traditional approach. First, the reversed pass maintains chamber stability by keeping the inner lip of the incision apposed to the roof of the tunnel, which keeps the incision partially sealed until the suture is tied and achieves complete closure. In contrast, the traditional suture entry separates the inner lip of the incision, leading to partial or complete anterior chamber collapse.

The reversed needle–pass technique is particularly helpful with toric, accommodating or multifocal IOLs, in which collapse of the anterior chamber would shift the IOL position or orientation. It is also helpful in cases of endothelial keratoplasty surgery, in which chamber collapse would lead to dislodgement or endothelial cell loss in the donor tissue.

The second advantage is that the needle exits the roof of the corneal tunnel pointing toward the apex of the cornea and away from adnexal tissues. If the patient moves the eye, the tip of the needle is pointing away from the eyelids, preventing a painful puncture of the lid margin.

Conclusion

The reversed-needle pass combined with the 1-1-1 knot is a deceptively simple technique with several significant advantages: It maintains chamber stability, allows suture tension adjustment and promotes easy burial of the suture knot in the tissue while preventing suture breakage. It also increases the surgeon’s efficiency. OM

References

1. Narváez J, Zumwalt M, Jones J, Mahdavi P. Reversed needle pass clear-corneal or limbal incision suturing technique using the 3-throw (1-1-1) adjustable square knot. J Cataract Refract Surg. 2012;38:929-932.

2. Leaming DV. Practice styles and preferences of ASCRS members—2003 survey. J Cataract Refract Surg. 2004; 30:892-900.

3. Sarayba MA, Taban M, Ignacio TS, Berens A, McDonnell PJ. Inflow of ocular surface fluid through clear corneal cataract incisions: a laboratory model. Am J Ophthalmol 2004; 138:206-210.

4. Harris DJ, Waring GO. A granny-style slip knot for use in eye surgery. Refract Corneal Surg. 1992;8:396-398.

5. Dangel ME, Keates RH. The adjustable slide knot—an alternate technique. Ophthalmic Surg. 1980;12:843-846.

6. Terry C. The differentially adjustable slide knot. Am Intraocular Implant Soc J. 1977; 3:197-198.

7. Chipont-Benabent E, Artola Roig A, Pérez-Santonja JJ, Guisbert Medel M, Alió Sanz JL. Astigmatism induced by intrastromal corneal suture after small incision phacoemulsification. J Cataract Refract Surg. 1998; 24:519-523.

8. Brouwers JE, Oosting H, de Hass D, Klopper PJ. Dynamic loading of surgical knots. Surg Gynecol Obstet. 1991; 173:443–448.

Julio Narváez, MD, practices with Delta Eye Medical Group, Stockton, Calif., and is professor of ophthalmology at Loma Linda University in California. His e-mail is narvaezjd@gmail.com. Disclosure: Dr. Narváez has no relevant relationships to disclose.