Akademik Veri Yönetim Sistemi
RANZCO Australian&NewZealand Strabismus Society Meeting 2021, Christchurch, Yeni Zelanda, 21 Mart 2021, ss.13-15
Purpose: To evaluate the algorithms, results and discuss some unspoken complications of
surgical treatments of vertical strabismus and diplopia associated with thyroid orbitopathy.
Methods: A retrospective case series, Patients who underwent TO-related vertical
strabismus surgery between January 2017 and February 2020 and were followed for at least
six months were included in the study. Preoperative activity scores of the cases (The VISA
classification), previous treatments; Pulse steroid and/or other immunosuppressive
treatments, External radiotherapy (ERT), orbital decompression surgeries (wall number)
were recorded. Hertel exophthalmometer was used for exophthalmos measurements; the
angle and Hertel scores were recorded. The interpalpebral fissures were measured. The
lower (scleral show) and upper eyelid retraction amounts were calculated in millimeters by
measuring the distance between the limbus and the lid edge while each eye was on central
fixation.
All surgical treatments were performed by a single experienced surgeon (KTÖ) in the
inactive period (VISA score <3) after at least six months of stability. Patients who operated
on for horizontal deviation in the same session were also included in the study. Surgeries
were applied to patients with diplopia, whose deviation amount was more than 10 prism
diopters (PD) and could not compensate with prisms. Expanded muscle is determined with
MRI, and surgery is planned with eye movements and a squint examination, and a forcedduction test. As a priority, when the deviation under 20 PD, recession was planned to only
the inferior rectus muscle (IR) by the maximum of 6 mm. However, superior rectus muscle
(SR) recession of the fellow eye was added if 20 PD or greater deviations. Calculations were
made assuming that the amount of recession would be 1 mm=3 PD correction in vertical
deviations. All surgeries were performed under general anesthesia, the muscles were
recessed with a fixed suture technique. In horizontal deviations, the medial rectus (MR)
muscles' recession was performed using a similar technique by an appropriate amount. Postoperative full ophthalmological examinations were performed at the 1st week, first
month, sixth month, and then annually, and the final strabismus examination findings in
stable condition, and additional treatments were recorded. 6th-month findings of the
eyelids and exophthalmos were used in the study. Non-parametric, Wilcoxon signed rank
test and chi-square tests were performed.
Results: A total of 11 patients, seven females and four males, were included in the study.
The mean age was 43.9 ± 7.9 (32-56) years, and the mean follow-up time was 22.3 ± 9.7 (9-
36) months. All patients had received pulse steroid therapy, and the mean total
prednisolone dose was 6.14 ± 1.96 (4.5-11) grams. Moreover, four patients had additionally
received ERT. Two wall (medial + inferior) orbital decompression had been performed in one
patient. No patient had preoperative signs of compressive optic neuropathy or severe
exposure keratopathy. Average preoperative VISA scores were 1.1 ± 0.7 (0-2).
Following transactions were performed to correct vertical deviations: IR recession in only
one eye (range: 4.5-6 mm) in 7 patients. In 3 patients, an IR recession (range: 4.5-5.5 mm) in
one eye and an SR recession in fellow eye (range: 4-7 mm). In one patient, due to
asymmetric IR involvement and severe upward gaze restriction, a bilateral but asymmetric
IR recession (6 and 3 mm). In 5 cases, due to accompanying esotropia, MR recession was
performed simultaneously (4 bilateral, one unilateral, range: 4-5.5 mm). The average
amount of vertical muscle recession was 7.23 ± 2.7 mm. With each 1 mm recession, 3.1 PD
vertical deviation was improved (calculated by taking the recession difference in the case
with bilateral IR recession). All patients, preoperative strabismic findings, surgeries
performed, and results are summarized in Table 1.
A minimal but insignificant increase was observed in the interpalpebral fissure in the eyes
undergoing surgery (p =0.180). However, the exophthalmos-Hertel scores increased
significantly in all eyes performed surgery (p =0.001). Scleral show was found to be
increased in all eyes performed surgery (p =0.004), besides this increase was more in eyes
performed IR recession (p =0.002). The average values in the preoperative and
postoperative examination findings and their comparison are summarized in Table 2.
Postoperative diplopia was corrected in 9 patients statistically significantly (82%, p=0.035) in
the primary position and downward gaze and tolerated with small prismatic glasses in 2
patients. As a result, one patient under-correction (4 PD) and one patient overcorrection (6
PD) in vertical squint, and one patient under-correction (6 PD) in horizontal squint were
observed. However, an acceptable cosmetic improvement was achieved in all patients.
One male patient, who continued to smoke and had previously taken ERT, developed TO
recurrence after the 1st year. The patient, who had wide-angle esotropia, increased
exophthalmos and eyelid retraction, was controlled with medical treatment, followed by
bilateral MR recession, followed by blepharoplasty with fat decompression, and
blepharotomy on the upper eyelids. Last, lower eyelid retraction on the side with excess
scleral show was treated with helical cartilage graft. Additional surgical interventions and
sequelae treatments are summarized in Table 3.
Conclusion: In thyroid orbitopathy, if vertical strabismus and diplopia cannot be eliminated
with conservative methods, performing a recession to vertical rectus muscles with a fixed
suture technique is quite effective and safe and has predictable results in a long period.
However, after surgery, an increase in exophthalmos and scleral show may become
noticeable, even if minimal. It would be better to warn patients about this regard.