|Year : 2018 | Volume
| Issue : 3 | Page : 123-126
Hang-back technique versus conventional rectus recession in strabismus surgery
Karim A Gaballah
Department of Ophthalmology, Helwan University, Helwan, Egypt
|Date of Submission||19-Aug-2018|
|Date of Acceptance||02-Sep-2018|
|Date of Web Publication||22-Nov-2018|
Dr. Karim A Gaballah
Department of Ophthalmology, Helwan University, 2 Morison street , Rouchdy, Alexandria, 21111
Source of Support: None, Conflict of Interest: None
Purpose The aim of this work was to study a new technique of rectus muscle weakening and compare it with the conventional method of muscle recession.
Patients and methods This was a prospective study performed between February 2015 and June 2016, and follow-up was carried out until June 2017. A total of 54 patients presenting with esotropia underwent medial rectus recession with the hang-back technique, and 30 patients underwent recession with the conventional method. The results of strabismus surgery in these two groups of esotropia, one of them treated with the hang-back technique and the other with conventional recession, are compared.
Results Surgical outcomes were not significantly different in the two treatment groups. The hang-back was found to be technically safer, avoiding the scleral pass, by attaching the muscle into the stump of the tendon.
Conclusion It seems that the modified recession by the hang-back technique can reduce the complications and risks involved in conventional recession, and it is safer and effective for muscle recession. It can decrease the risk of globe perforation, as the sclera behind the insertion of the medial recti is the thinnest part of the sclera.
Keywords: esotropia, hang-back, recession
|How to cite this article:|
Gaballah KA. Hang-back technique versus conventional rectus recession in strabismus surgery. J Egypt Ophthalmol Soc 2018;111:123-6
| Introduction|| |
The recession of the medial rectus is a measured retroplacement of the muscle from its original insertion. It is the easiest and most effective way of weakening the medial rectus and is the most commonly performed procedure in strabismus management .
If a recession is planned for a particular muscle, a suture is placed in the tendinous portion of the muscle, and the muscle is removed from its attachment to the sclera.
It is then recessed or moved backwards several mm and then attached to the sclera. This change from its original position to a new position further back on the sclera effectively relaxes the pull of the muscle and allows the eye to attain a straighter position.
The reported incidence of scleral perforation varies widely. One prospective study found the incidence of scleral perforation to be 5.1% .
The risk of scleral perforation appears to be greatest during reattachment of a muscle to the sclera, wherein the needle must carefully penetrate the sclera. The thinner the sclera, the risk of scleral perforation during conventional recession is more .
Recognition of a perforation is necessary before potential treatment can be considered. Scleral perforation probably goes unrecognized in many cases.
Recognized scleral perforations are often known by a small piece of uvea or a bead of vitreous on the tip of the suture needle. Indirect ophthalmoscopy to inspect the retina underlying the surgical site should be performed when a scleral perforation is suspected.
Most scleral perforations are small, even microscopic
The alternative technique of muscle weakening, the hang-back technique, is performed by starting with a limbal conjunctival incision, exposure, hooking and dissection of the muscle from the check ligaments, dissection of the muscle from the intermuscular septa, taking a central locking knot in the muscle bulk near the insertion, and two locking sutures at the two edges, and then the tendon of insertion is cut from the scleral insertion.
Calipers are used to measure the amount of hang-back along the length of the suture. The needles are entered into the tendon stump instead of the scleral attachment. The sutures are then tied over the needle holder. The needle holder is removed, allowing the muscle to hang-back by the predetermined amount. This technique has the advantage of avoiding scleral pass, removing the potential for the suture knot to slip if superficial and minimizing the risk of perforation if deep, and allows more recession to be planned ([Figure 1],[Figure 2],[Figure 3]).
The aim of this study was to compare an alternative method for rectus muscle weakening procedure, the hang-back technique, with the conventional method of muscle recession, as regards the technique, the expected results, and the possibility of minimizing the risk of complications such as scleral perforation and a lost or slipped muscle.
| Patients and methods|| |
This was a prospective study, including cases of esotropia, operated by two different techniques, presenting and operated between February 2015 and May 2016, in Alex Eye Center, and followed up until May 2017.
Informed written consent was obtained from each patient to be included in this study.
Patients were divided into two groups:
Group A included 48 patients undergoing medial rectus recession with the hang-back technique; in this technique, the medial rectus is exposed, dissected, a central locking knot in made in the muscle bulk, two locking knots at the edges, the muscle is disinserted, the sutures are attached to the stump of the original tendon of insertion, and the muscle is left to be hanged back by the distance in mm needed, avoiding the needle from passing in the sclera. Moreover, conjunctival recession at the end of surgery was carried out to just cover the surgical knot of the hang-back thread in the stump of the original insertion; the aim of this recession of the conjunctiva was to keep the underlying hanging thread straightened, not redundant, to ensure that the site of reattachment of the muscle be at the planned site. The second, group B, included 30 patients who underwent conventional recession. The results of strabismus surgery in these two groups of esotropia treated with two different techniques, the hang-back technique and the conventional recession, are compared.
Informed written consent was obtained from all patients before participating in this study.
| Results|| |
Comparison of preoperative data and postoperative outcomes between the hang-back and conventional recession groups ([Table 1]).
| Discussion|| |
Although the results of both methods of medial rectus muscle recession were comparable and no statistically significant difference was detected in the postoperative results, it seemed that the hang-back technique was more safe, especially when dealing with the needle having to pass through the thin sclera under the medial recti, and with the anatomical findings during surgery, that can direct the surgeon’s preference to pass the needle through the base of the insertion tendon with safety rather than to pass through an abnormally thin sclera underneath the medial recti. Moreover, when the medial rectus has to be recessed as far back as a 6 mm recession or more, the hang-back technique is much easier to perform, wherein the maintenance of parallelism of the spatulated needle to the sclera during muscle reattachment is somewhat difficult in the narrower surgical field, risking perforation if deep, and risking muscle loss or slippage if too superficial, whereas the attachment of the new insertion to the tendon stump, avoiding the scleral pass, seems safer.
Some studies on the comparison of hang-back with conventional bilateral lateral rectus recession for exotropia have not found any significant difference in the surgical success rates (≤10Δ of deviation) between the two techniques ,.
However, Capo et al.  found a significantly greater success rate in the conventional group than in the hang-back group in their patients with intermittent or constant exotropia. They attributed this difference mainly to late overcorrections in the hang-back group .
In the literature, many studies were carried out on the hang-back recession technique of the lateral recti, for correction of exotropia, perhaps to evaluate this procedure in a wider field of lateral recti ,, rather than to evaluate in the narrower field of recessing medial recti in esotropia, wherein the dissection of the medial recti from the intermuscular septum carries the risk of loss of the muscle in case of slipping.
To overcome this risk of muscle loss, a small modification is performed; in this study, a central locking knot is taken in the central part of the muscle bulk, then one locking knot at each edge of the muscle, so that the muscle is totally secured when clearly dissecting the intermuscular septa.
The conjunctival recession at the end of the surgery, to mechanically help straightening of the hang-back and in conventional recession, helps to relieve any conjunctival restrictive element. In a study by Özkan  on restrictive strabismus, she put in consideration the conjunctival element.
| Conclusion|| |
Although the postoperative results of the hang-back and the conventional recession technique are comparable, the hang-back technique seems to be more safe as regards avoiding passing the needle and suture in the sclera, avoiding perforation if deep, and avoiding muscle slippage if superficial, in addition to applying the modifications of a central secured knot in the muscle for safety, and with conjunctival recession at the end of surgery, the postoperative results were satisfactory.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]