Download Surgical Procedure Joining the Lateral Rectus and Superior Rectus

Surgical Procedure Joining the Lateral Rectus and
Superior Rectus Muscles With or Without Medial
Rectus Recession for the Treatment of Strabismus
Associated With High Myopia
Serpil Akar, MD; Birsen Gokyigit, MD; Erkin Aribal, MD; Abdulvahit Demir, MD; Yasin Sakir Göker, MD;
Ahmet Demirok
ABSTRACT
Purpose: To evaluate the outcomes of a surgical procedure involving the muscle union of the superior rectus (SR) and lateral rectus (LR) muscles with or without
medial rectus (MR) recession for the treatment of strabismus associated with high myopia and the anatomic
changes from before and after surgery.
Methods: Thirty-five eyes of 20 patients who had undergone a muscle union of the SR and LR muscles with
or without MR recession for treatment of acquired strabismus associated with an inferior displacement of the
LR and nasal displacement of the SR in magnetic resonance imaging of the orbit due to axial high myopia
were observed prospectively. Main outcome measures
were the angles of the dislocation of the globe, angles
of horizontal or vertical deviations, abductions, and supraductions. The angles of the dislocation of the globe
were analyzed using magnetic resonance imaging (1.5
Tesla Magnet; Siemens Symphonia, Munich, Germany).
INTRODUCTION
Adult patients with unilateral or bilateral high
axial myopia may acquire a typical restrictive motility disorder associated with obvious esodeviation
and hypodeviation named strabismus fixus convergens.1-4 The exact mechanism is not well understood, but several studies have noted a superotem-
Results: The axial lengths ranged from 26 to 36 mm
(mean: 30.6 ± 2.8 mm). The angle of dislocation of the
globe changed from 178º ± 10º to 101º ± 6º, the angle
of esotropia changed from 58.6 ± 2.5 to 6.8 ± 1.4 prism
diopters (PD); and the angle of hypotropia changed
from 12.5 ± 1.3 to 3.3 ± 1.1 PD postoperatively. Abduction and supraduction improved significantly after
surgery. At the 4-year follow-up, the postoperative outcomes were stable.
Conclusions: In the treatment of strabismus caused
by high myopia, the surgical procedure involving the
muscle union of the SR and LR muscles with or without
MR recession was effective on both the restoration of
the dislocated globe into the muscle cone and the improvement of ocular motility.
[J Pediatr Ophthalmol Strabismus 20XX;XX(X):XXXX.]
poral herniation of the elongated eyeball beyond the
muscle cone in the orbit.2,3
Surgical management of myopic strabismus fixus
is complex.4 Conventional maneuvers are resectionrecession procedures that mainly affect muscle forces.5,6 Modified procedures include transposition techniques that alter the muscle paths.4,7-10 Yokoyama et
From the Department of Pediatric Ophthalmology and Strabismus (SA, BG), Prof. Dr. N. Resat Belger Beyoglu Education and Research Eye Hospital
(ADemir, YSG, ADemirok), Istanbul, Turkey; and the Department of Radiology, Marmara University Hospital School of Medicine, Istanbul, Turkey (EA).
Submitted: March 6, 2013; Accepted: October 10, 2013; Posted online: November 26, 2013
The authors have no financial or proprietary interest in the materials presented herein.
Correspondence: Serpil Akar, MD, Acibadem cad, Yurtsever sok. Alsancak sitesi, E Blk, Da:19 Acibadem/Kadikoy/ Istanbul, Turkey. E-mail: akarserpil@
yahoo.com
doi: 10.3928/01913913-20131119-01
Journal of Pediatric Ophthalmology & Strabismus • Vol. xx, No. x, 20XX
1
al.8 and Yamaguchi et al.11 described a surgical procedure involving the muscle union of the superior rectus (SR) and lateral rectus (LR) muscles to restore the
dislocated globe back to the muscle cone.
The purpose of this study was to evaluate the
outcomes of a surgical procedure involving the muscle union of the SR and LR muscles with or without medial rectus (MR) recession for the treatment
of strabismus associated with high myopia and the
anatomic changes from before and after surgery.
PATIENTS AND METHODS
This was a single-center, prospective, consecutive cohort study. Approval from the Ethics Committee and the Institutional Review Board at the
Prof. Dr. N. Resat Belger Beyoglu Education and
Research Eye Hospital, Istanbul, Turkey, was obtained. Informed consent was obtained from each
participant. The study and data collection conformed to all local laws and was compliant with the
tenets of the Declaration of Helsinki.
The study population consisted of patients who
underwent surgery to unite the muscle bellies of the
LR and SR muscles with or without MR recession for
treatment of acquired progressive esotropia-hypotropia associated with high myopia. All procedures
were performed at Prof. Dr. N. Resat Belger Beyoglu
Education and Research Eye Hospital between July
2005 and January 2009. Patients fulfilling the following criteria were included in the study: axial high
myopia (axial length longer than 27 mm), acquired
strabismus (esotropia-hypotropia) associated with
an inferior displacement of the LR muscle, and
nasal displacement of the SR muscle in magnetic
resonance imaging (MRI) of the orbit. Patients with
neurological or developmental disorders and those
who had undergone previous strabismus surgery
were excluded from the study. Originally, this study
was designed with a 4-year follow-up after surgery.
No patients meeting the inclusion criteria were excluded from the study during the study period.
Before surgical intervention, all patients received complete ophthalmic and orthoptic examinations. The angle of ocular deviation was measured
by the alternate prism cover test at 6 and 0.33 m
with the patient’s optimum myopic correction.
For patients in whom neither eye could abduct
past the midline, the Krimsky test was used with
prisms placed in front of both eyes. The limitation
of ocular movements was divided into four grades
2
(-1 = minimal limitation, -4 = no movement toward
and/or beyond the primary position).4,9,10 A- and
B-scan echography (Ocuscan; Alcon Laboratories,
Inc., Fort Worth, TX) were performed in all patients
to determine the axial length of the globes.
The orbits of all patients were imaged using
MRI (1.5 Tesla Magnet, Siemens Symphonia, Munich, Germany). High-resolution coronal and axial
T2-weighted spin echo images were obtained with
the following settings: repetition time = 550 ms and
echo time = 15 ms, field of view = 21 3 21 cm, pixel
matrix = 256 3 512, three acquisitions, slice thickness 3 mm, and distance factor 0.25. All patients
were instructed to remain still in the infraducted
eye position. We tried to avoid the influence of gaze
position on the anatomic relationships between the
globe and extraocular muscles. Therefore, we controlled the gaze at the same position in all patients.
As suggested by Yokoyama et al.8 and Yamaguchi et
al.,11 we used infraduction to analyze the results of
MRI for every patient under the same conditions.
For the orbital measurement, we used a coronal
slice image 9-mm anterior to the globe-optic nerve
junction in each orbit to avoid any influence of globe
shape, such as staphyloma. On this slice image, we first
traced the outlines of the cross-sectional orbits and
the SR and LR muscles and then the area centroid of
each object was determined using the XY center tool
of the Syngo via postprocessing software (Siemens
A.G., Munich, Germany). Lines were drawn between
the orbital centroid and each extraocular muscle (LR
and SR) centroid. As recommended by Yokoyama et
al.8 and Yamaguchi et al.11 the angle of dislocation of
the globe was defined as the angle formed by a line
connecting the area centroid of the SR muscle and
the globe and another line connecting the area centroid of the LR muscle and the globe (including the
superior temporal quadrant of the orbit) (Figure 1).
The forced-duction test under general anesthesia for verifying restriction preoperatively was applied for all cases. Forced-duction testing was graded on a 3-point scale as mild, moderate, or severe.12
The forced-duction test was performed again postoperatively.
Surgical Technique
The surgical approach was conducted according
to the previous description by Yokoyama et al.8 All
surgeries were performed under general anesthesia.
As an initial procedure, the forced-duction test was
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A
B
Figure 1. The measurement of the angle of globe dislocation on a
coronal magnetic resonance image in a patient with highly myopic
strabismus (A) before and (B) after muscle union surgery. The angle
of globe dislocation before surgery is 165°, the angle of globe dislocation after surgery is 115°. S = superior rectus, L = lateral rectus,
G = the areas centroid of the globe.
performed on the affected eye. In case of mild or no
restriction of the MR muscle, we only performed
surgery for muscle union of the SR and LR muscles. In this surgery, a fornix-based conjunctival incision was made between the SR and LR muscles.
The SR and LR muscles were isolated and cleared
of the surrounding check ligaments and intermuscular septum. A double-armed 5-0 polybutilate-coated
polyester suture (Ethibond; Johnson & Johnson,
Sint-Stevens-Woluwe, Belgium) was placed by passing a needle through the lateral one-quarter of the
SR muscle and the other needle through the superior one-quarter of the LR muscle, positioning this
suture 14 to 15 mm posterior to the insertion of the
two muscles. The suture was then tied to pull the two
muscles together. The muscles did not split and there
was no attachment to the sclera (Figure 2).8,11 Conjunctiva was closed with an interrupted 8-0 polyglactin suture (Vicryl; Ethicon, Inc., Somerville, NJ). If
esotropia remained after the muscle union of the SR
and LR muscles, we added a MR muscle recession
later. In eyes that had MR contracture during the
forced-duction test, MR muscle recession (8 to 10
mm)4 was performed along with the muscle union.
Examinations were performed 1 week prior to
surgery and were repeated postoperatively at 1, 3,
6, and 12 months; thereafter, examinations were
performed on an annual basis for 4 years. Orbital
MRIs were performed 1 week prior to surgery and
were repeated postoperatively at 1 and 12 months;
thereafter, they were performed on an annual basis
for 4 years.
Statistical Analysis
The data were analyzed with SPSS version 16
for Windows, (SPSS, Inc., Chicago, IL). Descriptive
Figure 2. The superior rectus (SR) and lateral rectus (LR) muscles
joined with small bites from both muscle bellies without splitting.
The junction was made approximately 14 to 15 mm behind their
insertions.
statistics, mean, and standard deviation for numeric
variables were calculated. Differences between preoperative and first postoperative month values were
compared. The paired samples t test was used for
these comparisons. Dunn’s test was used for simultaneous estimation of all pairwise comparisons of
postoperative values at 1 month and 1, 2, 3, and 4
years. A P value less than .05 was considered statistically significant.
RESULTS
The study population consisted of 35 eyes from
20 patients (11 female, 9 male) who underwent the
union of the muscle bellies of the LR and SR muscles with or without recession of the MR muscle for
the treatment of highly myopic strabismus. All 20
patients had acquired progressive esotropia and hypotropia. The mean age of onset for strabismus was
34.8 ± 3.1 years (range: 21 to 44 years). Fifteen of
the 20 patients had bilateral high axial myopia, and
5 patients had unilateral high axial myopia. Their
axial lengths ranged from 26 to 36 mm (mean: 30.6
± 2.8 mm), and their spherical equivalents of refraction ranged from -10.00 to -28.00 diopters (mean:
-19.01 ± 3.1 diopters).
All patients were examined at 1 month and 1, 2,
3, and 4 years postoperatively.
The surgical results of patients with highly myopic strabismus are shown in Table 1. A statistically
significant difference was found between preoperative and first postoperative month values in the angle
Journal of Pediatric Ophthalmology & Strabismus • Vol. xx, No. x, 20XX
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TABLE 1
Surgical Results in Patients With Highly Myopic Strabismus
Variable
Preop
Postop
1 Month
Postop
1 Year
Postop
2 Years
Postop
3 Years
Postop
4 Years
No. of eyes/patients
35/20
35/20
35/20
35/20
35/20
35/20
Angle of dislocation of the globe (°)
(mean ± SD [min to max])
178 ± 10
(160 to 200)
101 ± 6
(90 to 115)
103 ± 5
(90 to 120)
102 ±9
(90 to 120)
101 ± 4
(90 to 120)
103 ± 7
(90 to 120)
Angle of esotropia (PD)
(mean ± SD [min to max])
58.6 ± 2.5
(50 to 90)
6.8 ± 1.4
(0 to 10)
6.7 ± 1
(0 to 10)
6.9 ± 1
(0 to 15)
6.7 ± 1.2
(0 to 15)
6.8 ±0.7
(0 to 15)
Angle of hypotropia (PD)
(mean ± SD [min to max])
12.5 ± 1.3
(8 to 20)
3.3 ± 1.1
(0 to 4)
3.5 ± 0.2
(0 to 5)
3.4 ± 0.1
(0 to 5)
3.2 ± 0.4
(0 to 5)
3.3 ± 0.05
(0 to 5)
Abduction
(mean ± SD [min to max])
-2.9 ± 1.6
(-2 to 4)
-0.7 ± 0.8
(0 to 2)
-0.7 ± 0.1
(0 to 2)
-0.8 ± 0.2
(0 to 2)
-0.9 ± 0.4
(0 to 2)
-0.7 ± 0.5
(0 to 2)
Supraduction
(mean ± SD [min to max])
-2.4 ± 0.9
(-1 to 3)
-0.6 ± 0.1
(0 to 2)
-0.6 ± 0.1
(0 to 2)
-0.7 ± 0.2
(0 to 2)
-0.5 ± 0.05
(0 to 2)
-0.7 ± 0.2
(0 to 2)
Preop = preoperative; postop = postoperative; SD = standard deviation; min = minimum; max = maximum; PD = prism diopter
of globe dislocation (P = .001). Figure 1 shows the
measurement of the angle of globe dislocation in a
patient with highly myopic strabismus. There were
statistically significant differences between preoperative and first postoperative month values in the
angles of horizontal and vertical deviations (P = .001
and .049, respectively). A statistically significant difference was found between preoperative and first
postoperative month values in abduction and supraduction (P = .001 and .038, respectively).
No significant differences were found between
1 month and 1, 2, 3, and 4 years postoperatively,
which reflects the stability of improvements in the
angle of globe dislocation, the angles of horizontal
and vertical deviation abduction, and supraduction
after surgery (P > .05 for each comparison).
The forced-duction test revealed positive results
(severe or moderate restriction) in the abduction of
24 eyes of 13 patients before surgery. The MR recession was performed at the same time as the muscle
union in these 24 eyes. After surgery, a forced-duction test in these eyes demonstrated negative results
in abduction. Nine eyes were cured only by uniting
the SR and LR muscles. We recessed the MR muscle
5 to 9 months later in 2 eyes of 2 patients because
they remained esotropic despite the union of the
SR and LR muscles. Two patients had -1 adduction
after larger MR recession operation.
No intraoperative or postoperative complications occurred in any treated eye.
Figure 3 shows preoperative and postoperative
photographs of one case.
4
DISCUSSION
Many surgical methods to stabilize the globe
in high myopia have been described, including tenotomy, large recession of the MR muscle, recession
of the nasal conjunctiva, recession-resection procedures and/or the traction suture, disinsertion, and
myectomy of MR muscles with LR resection.5,6,13-16
A large amount of the recession of the MR muscle
is effective in some cases, but relapse can occur.4,14,17
Krzizok et al. reported that a common recession and resection procedure may even aggravate
the deviation.13 Recently, several researchers have
paid special attention to the shift in the extraocular muscle paths in myopic strabismus fixus, reporting that these shifts were caused by a posterior
prolapse of an elongated eyeball beyond the muscle
cone in the orbit.2,3,8,14,18-20 Rutar and Demer suggested that LR-SR muscle band degeneration leads
to downward shift of the LR muscle.21 Noting the
displacement of the SR and LR muscles in myopic strabismus fixus, some authors have reported
the superior fixation of the LR muscle belly,13
hemitransposition of the SR and LR muscle,20 and
loop myopexi between the SR and LR muscle.22,23
Yokoyama et al. introduced a surgical procedure
uniting the muscle bellies of the SR and LR muscles
for patients with highly myopic strabismus fixus.8
Some authors reported that patients in whom contracture of the MR muscles was not found were
cured only by this procedure and the recession of
the MR muscle was not essential for treating highly
myopic strabismus.8,11
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Figure 3. (A) Preoperative photograph of a case with the left eye fixed in a position of extreme esotropia and hypodeviation. (B) Postoperative photographs showing the nine positions of gaze 1 month after surgery. Eye position and ocular motility markedly improved in all
directions.
In our study, the deviant paths of the SR and
LR muscles were confirmed with MRI either preoperatively or at the time of operation. We performed
surgical procedures involving the muscle union of
the SR and LR muscles with or without MR recession for the treatment of strabismus associated
with high myopia. To the best of our knowledge,
this study is the largest series in the literature. We
considered previous reports8,11 and recessed the
MR muscle at the same time as performing muscle
union when forced ductions confirm tight muscle.
In cases that had restricted abduction for several
years, contracture of the MR muscle is likely to
have occured.17
Yamaguchi et al.11 and Yokoyama et al.8 performed a surgical procedure involving the muscle
union of the SR and LR muscles with or without MR
recession in 23 eyes of 14 patients who had a diagnosis of highly myopic strabismus. They reported that
the preoperative angle of globe dislocation of 184°
decreased to 100° during the postoperative period
and the angle of ocular deviation of 58.8 prism diopters (PD) decreased to 0.7 PD postoperatively. They
revealed that this procedure was effective for restoring
the dislocated globe into the muscle cone and for improving both ocular motility and deviation.11
In the literature, some authors have presented
this procedure as useful for treating convergent
Journal of Pediatric Ophthalmology & Strabismus • Vol. xx, No. x, 20XX
5
strabismus fixus.24 We achieved satisfactory outcomes from uniting the muscle bellies of the SR and
LR muscles with or without MR recession in myopic strabismus cases. The preoperative mean angle
of globe dislocation of 178º decreased to 101º on
the postoperative period. The angle of horizontal deviation was 58.6 PD and decreased to 6.8 PD postoperatively, and the angle of vertical deviation was
12.5 PD and decreased to 3.3 PD postoperatively.
In all cases, abduction and supraductions were significantly improved after surgery. We observed that
the physiological muscle plane may be reestablished
by this surgery. Postoperatively, the angles of the dislocation of the globe, angles of horizontal or vertical deviations, abductions, and supraductions were
stable for all patients throughout the follow-up period. This procedure has many advantages, including
elimination of the risk of scleral perforation because
no suture is placed in the globe. Additionally, the risk
of anterior segment ischemia is eliminated or minimized because the anterior ciliary circulation would
be less compromised, as the muscles are not cut.
We determined that the surgical procedure involving the muscle union of the SR and LR muscles with or without MR recession was sufficient to
restore the dislocated globe back into the muscle
cone and to achieve improvement of esotropiahypotropia, abduction, and supraduction in patients with highly myopic strabismus. We especially
recommend an additional recession of MR muscle
when forced ductions confirm tight muscle. We observed that the postoperative outcomes remained
stable during the 4 years of follow-up.
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