Indian Journal of Ophthalmology - Case Reports

: 2021  |  Volume : 1  |  Issue : 3  |  Page : 577--579

True muscle transplantation surgery for large angle exotropia: A case series

Sonali Rao, Atulyakruti Gupta 
 Department of Ophthalmology, Pediatric and Squint Services, B. W. Lion's Super-Speciality Eye Hospital, Bengaluru, Karnataka, India

Correspondence Address:
Dr. Sonali Rao
SA 601, Shriram Surabhi Apts, Mallasandra Village, Holiday Village Road, Off Kanakpura Road, Bangalore - 560062, Karnataka


Managing large-angle exotropia (>70 PD) can be challenging with the various techniques available. In this case series, we present “True Muscle Transplantation"––a simple technique––to manage large-angle sensory exotropia as a possible alternative. Seven patients (four women and three men) of mean age 39.71 ± 17.38 years with sensory large-angle exotropia (>70 PD) underwent proposed surgery after detailed preoperative workup. The stump resected from MR was transplanted to LR and recessed. The mean preoperative deviation of 77.14 ± 4.52 PD base-in reduced to mean postoperative angle of 4.71 ± 4.42 PD at 6 months with good ocular alignment, no lateral incommittance, and no limitation of ductions in all patients. Stable results were maintained beyond 6 months. True Muscle Transplantation, therefore, has the potential of being a possible alternative.

How to cite this article:
Rao S, Gupta A. True muscle transplantation surgery for large angle exotropia: A case series.Indian J Ophthalmol Case Rep 2021;1:577-579

How to cite this URL:
Rao S, Gupta A. True muscle transplantation surgery for large angle exotropia: A case series. Indian J Ophthalmol Case Rep [serial online] 2021 [cited 2023 Jun 1 ];1:577-579
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Full Text

Management of very large angle horizontal strabismus is quite challenging.[1] For large-angle exotropia treatment, some have sponsored large bilateral lateral rectus (LR) recession as it leaves the medial rectus untouched for subsequent surgery,[2] whereas others have advocated a simultaneous three or four muscles surgery.[2] Techniques such as medial rectus resection with LR recession; bilateral medial rectus resection; botulinum toxin injection combined with recession-resection procedures, or along with augmented bilateral LR recession; combination of rectus muscle recessions with a central tenectomy[1]; supramaximal recession-resection; hangback-hemihangback recession and muscle recession with spacer have also been performed. However, deliberation still exists as to what would be the best management.[2]

We therefore present a simple technique––'True muscle transplantation'––as a possible alternative to manage large-angle sensory exotropia which gives promising stable results.

 Case Series

In this case series, 7 patients (four women + three men) with large angle sensory exotropia (>70 PD) who were insistent on single eye surgery were included. With IRB approval, informed consent from all patients was taken and these patients were subjected to detailed preoperative evaluation and refraction followed by true muscle transplantation surgery. Follow-up was done at 1 week, 1 month, 3 months, and 6 months.

The medial rectus was approached through a limbal conjunctival incision and hooked from the inferotemporal aspect. A double arm 6-0 vicryl suture was passed through its insertion followed by a 5-0 ethilon suture––passed at a desired distance from insertion as per standard resection procedure [details in [Table 1]], and the muscle was cut. The resected muscle was kept aside in saline and the retained medial rectus was anchored back at its original insertion with 6-0 vicryl sutures [Figure 1]a and [Figure 1]b.{Table 1}{Figure 1}

The LR was then approached through a limbal conjunctival incision - hooked and disinserted. The distal end of the resected medial rectus stump was sutured to the disinserted LR at its original insertion and secured with 5-0 ethilon suture. The now elongated muscle complex was anchored to sclera with 6-0 vicryl suture as per standard recession procedure [Table 1]c[Figure 1]c. Conjunctiva was closed with 8-0 vicryl sutures.

The mean preoperative angle of 77.14 ± 4.52 PD in the seven patients of mean age 39.71 ± 17.38 years [Table 1] was reduced to mean postoperative angle of 4.71 ± 4.42 PD at 6 months and the results were stable beyond the 6 months follow-up [Figure 2]. There was also no limitation of extraocular movements postoperatively [Figure 3], in all patients.{Figure 2}{Figure 3}


The usefulness of true muscle transplantation surgery in managing large-angle strabismus––primarily esotropia––has already been demonstrated with desirable results.[3],[4],[5],[6],[7],[8] However, a better understanding of its application in managing large-angle exotropia is yet to be explored.

The existing surgical techniques have limitations of their own. Excessive amount of resection or recession may lead to several disfigurements such as significant limitation of abduction, enophthalmos, and palpebral fissure narrowing in >6 mm medial rectus resection.[9] The hang back muscle recession may cause muscle collapse which increases the effective recession making results less predictable.[10] Spacers used to elongate the muscle also poses a threat of extrusion.[4] And the prolonged surgical time along with surgical scars at the operation site when three or more muscles are operated bilaterally decreases the interest of surgeons in these methods.[1]

We therefore present true muscle transplantation as a possible alternative in managing large-angle sensory exotropia which gave us desirable outcomes in our study.

Apart from the advantage of being a simple uniocular procedure that gives prolonged stable results; since muscle transplantation effectively increases the muscle length, results can be improved; and being an autograft chance of the transplanted muscle getting rejected are also virtually nil.[4] Although a study with a larger sample size and longer study duration is needed to understand its long-term outcomes. In the meantime, true muscle transplantation for managing large-angle sensory exotropia is a technique worthy of consideration.


True muscle transplantation surgery, a simple uniocular procedure giving long-term stable results, is a technique worth considering while managing large-angle sensory exotropia.

Declaration of patient consent

An informed consent has been given by all the patients to be included in this study and for the use of their photographs.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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