SINGLE-PASS FOUR-THROW PUPILLOPLASTY

Priya Narang, MS; Ashar Agarwal, MS, FRCS; Ashvin Agarwal, MD; and Amar Agarwal, MS, FRCS, FRCOphth

Single-Pass Four-Throw Pupilloplasty Technique

The single-pass four-throw (SFT) pupilloplasty technique involves a single pass in the anterior chamber followed by 4 throws taken through the loop that is withdrawn from the anterior chamber. The procedure is composed of the approximation loop, with no securing loop taken to ensure a traditional knot formation. It works on the principle of creating a helical configuration by intertwining the loop in a self-locking manner to prevent it from opening up.

The SFT technique is applicable in all cases that require a pupil reconstruction following a traumatic or cosmetic disfigurement of the pupil architecture. The technique also has varied applications in other procedures like pre-Descemet’s endothelial keratoplasty (PDEK) or any endothelial keratoplasty procedure, plus diseases such as Urrets-Zavalia syndrome and selected cases of angle-closure glaucoma.

Introduction

Pupil reconstruction is an essential treatment to prevent photophobia and filter the amount of light in cases such as traumatic mydriasis and atonic pupils. Surgical repair is of substantial benefit, as it has the potential to reduce visual glare and light sensitivity. Among various techniques that have been described for pupil reconstruction, SFT is one of the newer techniques that can be employed for pupilloplasty.^1–10 As the name suggests, a single pass of the polypropylene 10-0 suture on a long-arm needle is passed through the iris tissue followed by creation of a loop with 4 throws around it that slides inside the eye like a Siepser sliding knot. 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 is composed of 4 throws, thereby creating an intertwining of sutures that has a self-locking mechanism and prevents loosening of the suture loop.

The following list summarizes the indications for pupilloplasty^11–13:

• Corneal indications
  
  
  
  • Endothelial keratoplasty, especially in aphakic eyes or those with a deficient posterior capsule, to prevent the graft from getting displaced in the posterior segment, and to maintain an adequate anterior chamber for graft unrolling and placement
  
  
• Glaucoma-related indications
  
  
  
  • Angle-closure glaucoma
    
  • Plateau iris syndrome
    
  • Broad peripheral anterior synechiae
  
  
• Pupil-related indications
  
  
  
  • Traumatic mydriasis
    
  • Urrets-Zavalia syndrome
    
  • Iatrogenic iridectomies
    
  • Iris defect (congenital coloboma iris/corectopia/polycoria)

The amount of iris defect should be initially assessed, and an imaginary line drawn from the intended edges of the defect to the limbus. This marks the paracentesis site. Another paracentesis should be made approximately 45 to 90 degrees away (Figure 68-1A). Depending on the indication for surgery, pupillary stretching is performed with end-opening forceps to pull on the iris from every clock hour and break any possible synechiae that might be present. This step also helps in giving the immobile iris some elasticity (Figures 68-1 through 68-4).

It is a good practice to begin such surgeries with a trocar anterior chamber maintainer¹⁴ or an anterior chamber maintainer with infusion of fluid in the eye. Alternatively, the surgeon can also perform the procedure with viscoelastic (if posterior capsule is intact) in the anterior chamber. In the case of glued IOL, aphakic patients, or those with a deficient posterior capsule, the authors would refrain from the use of viscoelastic to prevent any viscoelastic from entering the posterior segment. In such cases, an anterior chamber maintainer can be used with infusion of balanced salt solution in the eye.

With end-opening forceps introduced through the paracentesis, grasp one edge of the iris defect (see Figure 68-1B). With the other hand, enter the eye using a 9-0 or 10-0 polypropylene suture on a straight long needle through the iris. At this time, the needle can be released (see Figure 68-1C). Introduce end-opening forceps through the other paracentesis, and grasp the other edge of the iris defect. Pass a 26-gauge needle through the primary paracentesis, and then pass it through the iris. Now the surgeon can release the iris and dock the suture needle into the 26-gauge needle to externalize the 10-0 suture needle (see Figures 68-1D through F). At this time, the intraocular polypropylene suture can be divided into 3 parts: distal, intermediate, and proximal. Using a dialer or a Sinskey hook, engage the distal part of the suture and form a loop in the anterior chamber (see Figure 68-2A). Externalize this loop using micrograspers, taking care to maintain the externalized loop immediately outside the paracentesis (see Figures 68-2B and C). At this stage, it is important to ensure that none of the suture parts has crossed over each other.

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