Journal of Pediatric Ophthalmology and Strabismus

Original Article Supplemental Data

Single Horizontal Muscle (Medial or Lateral Rectus) Transposition and Inferior Rectus Recession in Monocular Elevation Deficit: A Novel Surgical Technique

Uppal Gandhi, DNB; Ramesh Kekunnaya, MD, FRCS

Abstract

Purpose:

To describe a novel surgical technique for the treatment of monocular elevation deficit and report its short-term outcomes.

Methods:

This was a prospective interventional case series. It was an institutional-based study of 5 patients with monocular elevation deficit. A single horizontal rectus muscle was transposed to 2 mm from the insertion of the superior rectus muscle along the spiral of Tillaux, augmenting it with a non-absorbable suture taken 8 mm behind its insertion. The main outcome measures were primary position hypotropia and elevation deficit at 8 months postoperatively.

Results:

The mean age was 12.4 years (range: 6 to 26 years). Four patients underwent lateral rectus transposition and one underwent medial rectus transposition. Inferior rectus recession was done in all patients. The mean follow-up period was 8 months (range: 6 to 12 months). The mean hypotropia reduced from 34.6 prism diopters (PD) (range: 20 to 48 PD) preoperatively to 0.8 PD (range: −4 to 8 PD) at 8 months postoperatively. Additionally, 3 patients had exotropia with a mean of 12 PD (range: 2 to 20 PD) and 2 had esotropia with a mean of 28.5 PD (range: 12 to 40 PD); 1 underwent lateral rectus recession and 1 medial rectus recession. Three patients did not require any horizontal muscle surgery. The mean elevation deficit in abduction, straight up gaze, and adduction improved from 4.4, 3.2, and 2.8 to 2.0, 2.0, and 1.8, respectively. The mean depression deficit was 0.5. No adverse effects were noted.

Conclusions:

Single horizontal muscle transposition with inferior rectus recession allows sparing of at least one horizontal muscle and achieves adequate elevation effect and primary position deviation correction, at least in the short-term follow-up.

[J Pediatr Ophthalmol Strabismus. 2019;56(3):183–187.]

Abstract

Purpose:

To describe a novel surgical technique for the treatment of monocular elevation deficit and report its short-term outcomes.

Methods:

This was a prospective interventional case series. It was an institutional-based study of 5 patients with monocular elevation deficit. A single horizontal rectus muscle was transposed to 2 mm from the insertion of the superior rectus muscle along the spiral of Tillaux, augmenting it with a non-absorbable suture taken 8 mm behind its insertion. The main outcome measures were primary position hypotropia and elevation deficit at 8 months postoperatively.

Results:

The mean age was 12.4 years (range: 6 to 26 years). Four patients underwent lateral rectus transposition and one underwent medial rectus transposition. Inferior rectus recession was done in all patients. The mean follow-up period was 8 months (range: 6 to 12 months). The mean hypotropia reduced from 34.6 prism diopters (PD) (range: 20 to 48 PD) preoperatively to 0.8 PD (range: −4 to 8 PD) at 8 months postoperatively. Additionally, 3 patients had exotropia with a mean of 12 PD (range: 2 to 20 PD) and 2 had esotropia with a mean of 28.5 PD (range: 12 to 40 PD); 1 underwent lateral rectus recession and 1 medial rectus recession. Three patients did not require any horizontal muscle surgery. The mean elevation deficit in abduction, straight up gaze, and adduction improved from 4.4, 3.2, and 2.8 to 2.0, 2.0, and 1.8, respectively. The mean depression deficit was 0.5. No adverse effects were noted.

Conclusions:

Single horizontal muscle transposition with inferior rectus recession allows sparing of at least one horizontal muscle and achieves adequate elevation effect and primary position deviation correction, at least in the short-term follow-up.

[J Pediatr Ophthalmol Strabismus. 2019;56(3):183–187.]

Introduction

Monocular elevation deficit is classically described as hypotropia of the affected eye with deficiency of elevation in up gaze. However, it is commonly associated with horizontal deviation. The treatment primarily revolves around surgery aiming to correct the hypotropia in primary gaze and to improve the elevation to the extent possible. Currently, monocular elevation deficit is managed by inferior rectus recession or combined with Knapp's procedure or even a staged procedure based on the surgeon's experience. In Knapp's procedure, both horizontal recti are transposed, leaving no alternative to correct any significant horizontal deviation.1 The possibility of anterior segment ischemia is always present with Knapp's procedure, especially when combined with inferior rectus recession.2 There is also evidence of postoperative drift toward overcorrection with time. To overcome these drawbacks, several modifications of Knapp's procedure have been described in the literature with variable success rates, but there is no single technique that can optimize these issues. The purpose of this study was to describe a novel surgical technique for the treatment of monocular elevation deficit and report its 6-month outcomes.

Patients and Methods

A prospective interventional study was conducted at the L.V. Prasad Eye Institute, Hyderabad, India, from March 2017 to March 2018. The study was approved by the institute's review board and adhered to the tenets of the Declaration of Helsinki. Five patients with monocular elevation deficit were included in the study.

Preoperative work-up included a complete history, a systemic examination, and an ocular examination including best corrected visual acuity, a full orthoptic check-up, and measurement of deviation. Ductions, versions, and abnormal head posture were measured. Ptosis and Bell's phenomenon were assessed. Fundus photography was done to document any torsion objectively. Binocular status was assessed by Worth's four-dot and Titmus stereoacuity tests.

Forced duction testing was performed intraoperatively in all cases. Graded inferior rectus recession was done routinely using an inferotemporal Swan incision in all cases. A modified Swan incision was made in the superotemporal or superonasal quadrant depending on whether the lateral rectus or medial rectus muscle was to be transposed. For example, if lateral rectus transposition to the superior rectus muscle was planned, we made a Swan incision in the superotemporal quadrant and extended it toward the superior rectus and lateral rectus muscles. Only one horizontal rectus muscle was transposed upward to 2 mm from the insertion of the superior rectus muscle along the spiral of Tillaux. It was further augmented with a non-absorbable 5-0 Mersilene (Ethicon, Somerville, NJ) suture at 8 mm from the superior rectus insertion incorporating one-quarter width of both the transposed rectus and the superior rectus with a bite taken from the adjacent sclera (Figure 1).The decision to transpose the lateral rectus or medial rectus muscle depended on the type of horizontal deviation. The lateral rectus muscle was transposed to the superior rectus muscle in cases with esotropia and the medial rectus muscle was transposed to the superior rectus muscle in cases of exotropia, leaving the other horizontal muscle for recession. If significant horizontal deviation was present, then the other “spared” rectus muscle was recessed depending on the amount of deviation through the same modified Swan incision. The conjunctiva was closed with either absorbable 6-0 sutures or fibrin glue.

Diagrammatic representation of the surgical technique of lateral rectus transposition (LRT) and augmentation with a nonabsorbable suture at 8 mm from the insertion of the superior rectus (SR) muscle along with inferior rectus (IR) and medical rectus (MR) recession.

Figure 1.

Diagrammatic representation of the surgical technique of lateral rectus transposition (LRT) and augmentation with a nonabsorbable suture at 8 mm from the insertion of the superior rectus (SR) muscle along with inferior rectus (IR) and medical rectus (MR) recession.

The patients were followed up at 1 day, 5 weeks, 3 months, and 6 months postoperatively. The main outcome parameters studied at each follow-up visit were postoperative vertical and horizontal alignment in primary gaze, improvement of elevation, objective and subjective torsional changes, and binocular status. Statistical analysis was done using the SPSS software (SPSS, Inc., Chicago, IL).

Results

Of the 5 patients, 4 were males and 1 was female. The mean age was 12.4 years (range: 6 to 26 years). The mean visual acuity in the involved eye was 0.34 logarithm of the minimum angle of resolution (log-MAR) (range: 0.15 to 0.5 logMAR). All patients had strabismic amblyopia in the involved eye with no binocular single vision preoperatively. Figures AD (available in the online version of this article) show the preoperative and postoperative results.

Patient 1 with monocular elevation deficit. (Top left) The patient has significant hypotropia and esotropia in the primary position preoperatively. (Top right) At 7 months after lateral rectus transposition with Foster's augmentation and medial rectus recession, the patient shows significant improvement in both the horizontal and vertical deviation. (Bottom left) A −3 limitation of elevation is seen preoperatively in primary up gaze. (Bottom right) At 7 months postoperatively, the limitation of elevation has reduced to −1.

Figure A.

Patient 1 with monocular elevation deficit. (Top left) The patient has significant hypotropia and esotropia in the primary position preoperatively. (Top right) At 7 months after lateral rectus transposition with Foster's augmentation and medial rectus recession, the patient shows significant improvement in both the horizontal and vertical deviation. (Bottom left) A −3 limitation of elevation is seen preoperatively in primary up gaze. (Bottom right) At 7 months postoperatively, the limitation of elevation has reduced to −1.

Patient 2 with monocular elevation deficit. Preoperatively the patient has more limitation of elevation in abduction. (Top left) Compared in straight up gaze (top center) and in adduction (top right), postoperatively there is improvement in the elevation, especially in abduction (bottom left), and also in straight up gaze (bottom center) and adduction (bottom right).

Figure B.

Patient 2 with monocular elevation deficit. Preoperatively the patient has more limitation of elevation in abduction. (Top left) Compared in straight up gaze (top center) and in adduction (top right), postoperatively there is improvement in the elevation, especially in abduction (bottom left), and also in straight up gaze (bottom center) and adduction (bottom right).

Patient 3 with monocular elevation deficit. (Top left) The patient has significant hypotropia and moderate esotropia in the primary position preoperatively. (Top right) At 12 months after lateral rectus transposition with Foster's augmentation alone, the patient shows significant improvement in both the vertical and horizontal deviation. (Bottom left) A −4 limitation of elevation is seen preoperatively in primary up gaze. (Bottom right) At 12 months postoperatively, the limitation of elevation has reduced to −3.

Figure C.

Patient 3 with monocular elevation deficit. (Top left) The patient has significant hypotropia and moderate esotropia in the primary position preoperatively. (Top right) At 12 months after lateral rectus transposition with Foster's augmentation alone, the patient shows significant improvement in both the vertical and horizontal deviation. (Bottom left) A −4 limitation of elevation is seen preoperatively in primary up gaze. (Bottom right) At 12 months postoperatively, the limitation of elevation has reduced to −3.

Patient 4 with monocular elevation deficit. Preoperatively the patient has a −5 limitation of elevation in abduction (top left) compared to a −4 limitation in straight up gaze (top center) and a −3 limitation in adduction (top right). Postoperatively there is improvement in the elevation, especially in abduction (bottom left), and also in straight up gaze (bottom center) and adduction (bottom right).

Figure D.

Patient 4 with monocular elevation deficit. Preoperatively the patient has a −5 limitation of elevation in abduction (top left) compared to a −4 limitation in straight up gaze (top center) and a −3 limitation in adduction (top right). Postoperatively there is improvement in the elevation, especially in abduction (bottom left), and also in straight up gaze (bottom center) and adduction (bottom right).

The preoperative mean hypotropia was 34.6 PD (range: 20 to 48 PD). Associated horizontal deviation was seen in all patients, 3 of whom had exotropia with a mean of 12 PD (range: 3 to 20 PD) and 2 of whom had esotropia with a mean of 28.5 PD (range: 12 to 45 PD). The mean elevation deficit in abduction, straight up gaze, and adduction was 4.4, 3.2, and 2.8, respectively (Table 1). Four patients had both true ptosis and pseudoptosis (one of whom also had Marcus Gunn jaw winking phenomenon) and one patient had only pseudoptosis.

Preoperative and Postoperative Data in the Series of 5 Patients With Monocular Elevation Deficit

Table 1:

Preoperative and Postoperative Data in the Series of 5 Patients With Monocular Elevation Deficit

Four patients underwent lateral rectus transposition and 1 patient underwent medial rectus transposition. All patients underwent graded inferior rectus recession ranging from 4 to 6 mm. Patient 1 underwent lateral rectus transposition and inferior rectus recession along with bilateral medial rectus 5-mm recession in the right eye. Patient 4 underwent medial rectus transposition and inferior rectus recession and lateral rectus 8-mm recession in the right eye. Intraoperative forced duction testing revealed inferior rectus muscle tightness in 3 patients (Table 2). The mean follow-up period was 8 months. At the last visit, the mean postoperative hypotropia was 0.8 PD. The mean elevation deficit at the last follow-up visit was 2, 2, and 1.8 in abduction, straight up gaze, and adduction, respectively. The mean depression deficit postoperatively was 0.5 (Table 1).

Vertical Deviation Preoperatively and Postoperatively, Intraoperative FDT (for IR), Amount of IR Recession, and Follow-up Period

Table 2:

Vertical Deviation Preoperatively and Postoperatively, Intraoperative FDT (for IR), Amount of IR Recession, and Follow-up Period

Postoperatively, 4 of the 5 patients had correction of vertical deviation within 5 PD. There were no overcorrections (> 10 PD) or undercorrections (< 10 PD) noted in our series until the last follow-up visit. Three patients achieved orthotropia for vertical deviation, 1 patient had an undercorrection of 6 PD, and 1 patient had an overcorrection of 4 PD at the last follow-up visit (Table 2). Both patients who underwent simultaneous horizontal muscle surgery were corrected to within 10 PD postoperatively. There was inferior scleral show in 2 patients postoperatively. There was no significant gain in the binocularity in any of the patients. No other adverse effects such as torsion or anterior segment ischemia were noted until the last follow-up visit.

Discussion

An average correction of 34 PD of the primary position hypotropia was achieved with single horizontal muscle transposition (augmented with a non-absorbable suture at 8 mm from the insertion of superior rectus muscle) and inferior rectus recession in our series. This was comparable to previous studies of Knapp's procedure with inferior rectus recession. In a series by Bandyopadhyay et al.,2 3 patients underwent inferior rectus recession followed by Knapp's procedure and the average correction of hypotropia reported was 28.6 PD. Kocak-Altintas et al.3 reported an average correction of 25.8 ± 5.6 PD after the combined surgery. Bagheri et al.4 reported a correction of 23.75 PD after the two procedures. On the other hand, Scott and Jackson5 obtained a correction of 38 PD after the combined surgery.

Horizontal deviation is commonly associated with monocular elevation deficit, as noted by Burke et al.6 (58%, 11 of 19 patients), Bandyopadhyay et al.2 (25%, 7 of 28 patients), and Talebnejad et al.7 (28%, 5 of 18 patients). Simultaneous recession and resection in Knapp's procedure has been tried to resolve horizontal deviation without obtaining good results, leading to the need for surgery in the normal fellow eye. This was tried by Cooper and Greenspan8 in one case and they recommended that the horizontal deviation should be corrected by a second surgery on the other eye because this modification was not effective. Dunlap et al.9 reported good results in 10 of 22 patients in whom simultaneous recession-resection with a graded Knapp's procedure was done. However, the outcomes may have been good because these patients with monocular elevation deficit had a small vertical deviation and large accompanying horizontal deviation.

We also believe that the transposed muscles cannot be effectively recessed or resected. A recessed muscle would decrease the effect of the transposed muscle and the resected muscle will cause further stretching to an already stretched muscle.10 Moreover, applying a non-absorbable augmentation suture will be extremely difficult even if a resected muscle is successfully transposed because it will lead to further stretching of the muscle. Our procedure addresses these issues, allows sparing of one horizontal rectus muscle, and thus avoids the need for surgery on the normal eye unless the accompanying horizontal deviation is large (eg, patient 1 in the current series). In their series of 10 patients, Kamlesh and Dadeya10 attempted to overcome this by splitting the horizontal muscles, transposing the superior halves, and performing recession and resection of the inferior halves. They reported a mean correction of 25 PD of vertical deviation and 20 PD of horizontal deviation. Nagpal et al.11 recently applied Challahan's procedure of transposition of the horizontal muscles instead of splitting them and recessing and resecting the lower segments. In our opinion, when an entire horizontal muscle is transposed to the superior rectus muscle along with augmentation by a non-absorbable suture, it will provide more force along the vertical axis, thus improving the elevation further.

The main concern was whether transposing a single horizontal muscle would cause subjective torsion postoperatively. In our series, there were no torsional changes in any of the patients subjectively until the last follow-up visit. This may be because none of the patients had binocular single vision preoperatively. However, the torsion was not studied objectively with fundus photography preoperatively and postoperatively in all patients.

Drift toward overcorrection with time is well known with Knapp's procedure. In a series of 19 patients with monocular elevation deficit, Burke et al.6 observed that overcorrection occurred in 3 of 6 patients who had undergone prior inferior rectus recession and in 2 of 13 patients who had no prior inferior rectus recession. The mean drift postoperatively was 12.2 PD over an average follow-up of 78.2 months. Transposition of a single horizontal muscle may reduce the chances of such overcorrections. In our series, we observed an overcorrection of 4 PD in one patient at the 12-month follow-up visit (Table 2). Although the postoperative results appeared promising at 6 months, longer study periods are required to establish whether single muscle transposition has an advantage over two-muscle transposition (Knapp's procedure) in regard to over-correction with time.

Although rare, the risk of anterior segment ischemia is always there, especially when inferior rectus recession is combined with Knapp's procedure, whether it is done in the same sitting or at a later stage.2 Sparing one rectus muscle, especially the medial rectus, may significantly alleviate the occurrence of this dreaded complication. However, in cases with coexisting horizontal deviation, simultaneous recession of the remaining horizontal muscle (lateral rectus or medial rectus) was done in our series (2 patients), thus involving three rectus muscles. This was supported by a recent study12 in which Tibrewal and Kekunnaya reported their experience of operating on three rectus muscles in the same session in 87 patients over 11 years. In their study, the most common indication for simultaneous surgery on three rectus muscles was monocular elevation deficit (35%). Overall, 2 of 87 (2.3%) patients developed anterior segment ischemia and the surgery involved two vertical rectus muscles and one horizontal muscle. None of the patients who underwent surgery on two horizontal rectus muscles and one vertical rectus muscle developed anterior segment ischemia. One of the possible reasons would be the use of fornicial incisions instead of limbal incisions, which can lead to disruption of the perilimbal conjunctival–Tenon's collateral circulation.

Conclusion

Single horizontal muscle transposition (lateral rectus or medial rectus) along with augmentation by a non-absorbable suture at 8 mm from the insertion of superior rectus muscle and simultaneous inferior rectus recession achieves good correction of hypotropia in the primary position along with good improvement of elevation. An ipsilateral horizontal muscle surgery can be done simultaneously when needed. There were no torsional changes and over-corrections up to 8 months of follow-up. This novel procedure can be considered as a primary procedure in cases of monocular elevation deficit with or without coexisting horizontal deviation as an alternative to the classic Knapp's procedure.

References

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  2. Bandyopadhyay R, Shetty S, Vijayalakshmi P. Surgical outcome in monocular elevation deficit: a retrospective interventional study. Indian J Ophthalmol. 2008;56:127–133. doi:10.4103/0301-4738.39117 [CrossRef]
  3. Kocak-Altintas AG, Kocak-Misirlioglu I, Dibal H, Duman S. Selective management of double elevator palsy by either inferior rectus recession and/or Knapp type transposition surgery. Binocular Vision & Strabismus Quarterly. 2000;15:39–46.
  4. Bagheri A, Sahebghalam R, Abrishami M. Double elevator palsy, subtypes and outcomes of surgery. J Ophthalmic Vis Res. 2008;3:108–113.
  5. Scott WE, Jackson OB. Double elevator palsy: the significance of inferior rectus restriction. Am Orthopt J. 1977;27:5–10. doi:10.1080/0065955X.1977.11982416 [CrossRef]
  6. Burke JP, Ruben JB, Scott WE. Vertical transposition of the horizontal recti (Knapp procedure) for the treatment of double elevator palsy: effectiveness and long-term stability. Br J Ophthalmol. 1992;76:734–737. doi:10.1136/bjo.76.12.734 [CrossRef]
  7. Talebnejad MR, Roustaei GA, Khalili MR. Monocular elevation deficiency: a case series of surgical outcome. Iran J Med Sci. 2014;39:102–106.
  8. Cooper EL, Greenspan J. Operation for double elevator paralysis. J Pediatr Ophthalmol. 1971;8:8–14.
  9. Dunlap EA. Vertical displacement of horizontal recti. Symposium on Strabismus Transactions of the New Orleans Academy of Ophthalmology. St. Louis: Mosby; 1971:307–329.
  10. Kamlesh, Dadeya S. Surgical management of unilateral elevator deficiency associated with horizontal deviation using a modified Knapp's procedure. Ophthalmic Surg Lasers Imaging. 2003;34:230–235. doi:10.3928/1542-8877-20030501-16 [CrossRef]
  11. Nagpal RC, Raj A, Maitreya A. Congenital double elevator palsy with sensory exotropia: a unique surgical management. J Ophthalmic Vis Res. 2017;12:222–224.
  12. Tibrewal S, Kekunnaya R. Risk of anterior segment ischemia following simultaneous three rectus muscle surgery: results from a single tertiary care centre. Strabismus. 2018;26:77–83. doi:10.1080/09273972.2018.1450429 [CrossRef]

Preoperative and Postoperative Data in the Series of 5 Patients With Monocular Elevation Deficit

Patient Preoperative Postoperative Last Visit


Hypo (PD) Exo (PD) Eso (PD) Elevation Limitation Hypo (D) Exo (PD) Eso (PD) Elevation Limitation


Add UG Abd Add UG Abd
1 48 NA 45 2 3 5 0 NA 4 1 1 1
2 25 14 NA 2 2 4 −4 0 NA 2 2 2
3 40 NA 12 4 4 5 8 NA 8 3 3 3
4 40 20 NA 3 3 3 0 8 X′ NA 2 2 2
5 20 3 NA 3 4 5 0 NA 2 2 2 2

Vertical Deviation Preoperatively and Postoperatively, Intraoperative FDT (for IR), Amount of IR Recession, and Follow-up Period

Patient Preoperative Hypotropia (PD) Intraoperative FDT (for IR) Amount of IR Recessiona Done (mm) Postoperative Hypotropia (PD)

1 Day 6 Weeks 6 Months Follow-up (Mo)
1b 48 +2 5 25 8 0 7
2 25 Negative 4 12 −2 −4 12
3 40 Negative 6 6 0 6 8
4c 40 +3 4 5 0 0 6
5 20 +2 5 8 0 0 7
Authors

From the Child Sight Institute, Jasti V. Ramanamma Children's Eye Care Centre, L.V. Prasad Eye Institute, Hyderabad, India.

The authors have no financial or proprietary interest in the materials presented herein.

Correspondence: Ramesh Kekunnaya, MD, FRCS, Child Sight Institute, Jasti V. Ramanamma Children's Eye Care Centre, L.V. Prasad Eye Institute, L.V. Prasad Marg, Banjara Hills, Hyderabad 500034, Telangana, India. E-mail: rameshak@lvpei.org

Received: December 06, 2018
Accepted: February 14, 2019

10.3928/01913913-20190306-01

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