Stiffened hang-back: A suggested modification using cyanoacrylate glue.

Sir,

We are sharing our experiment on the use of cyanoacrylate glue in an attempt to prevent the central sag of the muscle edge, a common finding during hang-back recessions.

First introduced by Repka and Guyton, hang-back recessions have been performed for several years as an alternative to conventional strabismus surgery.[1] The hang-back technique is most useful in cases of combined strabismus and retinal detachment surgery, those with risk of scleral perforation such as high myopia and other cases with the thin sclera. Hang-back may be especially useful in children with small globes, where it may be difficult to make a posterior scleral pass in case of large recessions.[2] It is also less time consuming. However, a major problem noticed, is the posterior bowing of the muscle that may lead to overcorrection, with this in mind and considering the increasing use of cyanoacrylate glue in ophthalmology, we thought of using this glue to avoid sagging of the muscle. Cyanoacrylate has been used as an effective, safe and bio-tolerant alternative to sutures for re-attaching rectus muscles in recession surgeries. Studies have shown that the muscle-sclera bond achieved using cyanoacrylate can withstand loads far more than the maximum force of 75 g generated by the human extra-ocular muscles.[34] Cyanoacrylates need minimal hydration to polymerize. The tensile strength of the bond is highest of all glues.[56] They form a solid impermeable mass in situ, a property, which can be used to advantage to stiffen the muscle edge and prevent sagging as we demonstrated in animal eyes. We exposed the rectus muscle of a goat's eye. Prior to dis-insertion, we secured the muscle with a 6–0 double armed Vicryl suture: A single bite through the center, and two locking bites through the edges. The 6–0 Vicryl sutures were passed through the insertion stump, and the edge allowed to hang-back [Figure 1]. At the posterior edge of the muscle increasing traction was applied using gradually increasing weights, up to 50 g over a pulley arrangement to mimic the pulling forces.

Figure 1

Hang-back technique, note the posterior bowing of the muscle edge

In the second eye, a similar procedure was carried out, except for applying a strip of iso-amyl-cyanoacrylate (IAC) glue to the dis-inserted muscle edge and allowing 45 s for the glue to polymerize and stiffen [Figure 2].

Figure 2

Iso-amyl-cyanoacrylate glue applied to the cut edge of the muscle, there is no central sag and the muscle edge appears straight

We found that the muscle edge with the IAC continued to maintain its stiffness and resisted deformation for up to 4 h under a continuous strain of 50 g force.

We are of the opinion that IAC stiffened hang-back recessions will prevent the muscle edge from sagging during muscle-scleral “take,” and thus prevent possible overcorrection. We also believe that the stiffened muscle edge may not favor forward migration to reattach on the sclera, decreasing the possibility of significant under correction. Undoubtedly, this idea needs to be confirmed in a clinical environment.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.