Surgical management of dissociated vertical deviation associated with A-pattern strabismus

Surgical management of Helveston syndrome (Triad exotropia)

Purpose

To evaluate and compare different surgical approaches for the treatment of Helveston syndrome and provide further information for preoperative planning.

Methods

From February 2008 to December 2018, data of 52 patients with Helveston syndrome were retrospectively reviewed. Different surgical approaches were selected based on the extent of A-pattern exotropia, dissociated vertical deviation (DVD), and both superior oblique muscle overaction (SOOA) with fundus photograph intorsion. Eye position, A-pattern, DVD, superior oblique muscle function, and binocular vision function were evaluated pre- and postoperatively. The average follow-up duration was 20.5 months.

Results

Nine cases underwent simultaneous horizontal deviation correction with bilateral superior rectus recession, 24 underwent simultaneous horizontal deviation correction with bilateral superior oblique muscle lengthening, and 19 underwent two stages of horizontal deviation correction with superior oblique muscle lengthening, and later bilateral superior rectus recession. A-pattern, DVD, SOOA, and fundus intorsion were all collapsed in all patients postoperatively. Forty-five patients had an orthophoric eye position with considerably aligned ocular movements postoperatively. The total success rate was 86.5%. Postoperatively, eight of the 10 patients with diplopia experienced a recovery of binocular single vision and three had a recovery of rudimentary stereopsis (Titmus 3000–400 s of arc). The compensatory head posture of patients improved significantly postoperatively.

Conclusions

The surgical planning of Helveston syndrome should be designed based on the degree of the A-pattern, SOOA, DVD, and the intorsion in fundus photographs, and the appropriate approach should be selected to improve patient satisfaction.

Graded superior oblique tendon suture lengthening: A novel procedure

PURPOSE

Literature regarding different superior oblique (SO) weakening procedures showed variable results. Here, we aim to evaluate the effect of a novel superior oblique tendon suture lengthening (SOSL) procedure on weakening of SO in patients with A-pattern exotropia associated with dissociated vertical deviation and SO overaction (triad exotropia).

METHODS

The medical records of triad exotropia patients who underwent SOSL or SO tenotomy were reviewed. Surgical results of SOSL procedure mainly regarding the correction of A pattern, SO overaction, and fundus intorsion were analyzed and compared with those of SO tenotomy procedure.

RESULTS

SOSL demonstrated comparable efficacy in correction of A pattern (20.2^△ ± 10.7^△ vs 29.2^△ ± 16.1^△, p = 0.172), normalization of SO overaction (1.9 ± 0.9 vs 2.4 ± 1.5, p = 0.349), and conversion of fundus intorsion (11.1° ± 7.0° vs 11.3° ± 4.4°, p = 0.691) as SO tenotomy. Moreover, the success rate of A pattern collapse was significantly higher in the SOSL group than in the SO tenotomy group (86% vs 40%, p = 0.028). None of the patients in the SOSL group, but two in the SO tenotomy group, presented SO palsy postoperatively. In the SOSL group, the corrected magnitude of SO overaction strongly correlated with the dosage of suture lengthening (p < 0.001).

CONCLUSION

SOSL procedure could effectively eliminate the clinical manifestations associated with SO overaction. The graded dosage of SOSL leads to more controllable and predictable results compared to SO tenotomy, which makes SOSL a good alternative choice for SO weakening.

Surgical management of Helveston syndrome (triad of A- pattern exotropia, superior oblique overaction and dissociated vertical deviation) using 'Four Oblique' procedure

Purpose:

To report the surgical outcomes in six patients of Helveston syndrome using a “four oblique” procedure. The popular methods for surgical management include superior rectus recessions alone or combined with superior oblique tenectomy. However, large angle exotropia correction would entail a higher risk of anterior segment ischemia when the superior rectus needs to be operated along with the horizontal recti. Hence, we evaluated the long-term results of this uncommon procedure.

Methods:

This was a retrospective review of six patients diagnosed to have manifest dissociated vertical deviation (DVD) with A pattern exotropia with bilateral superior oblique over action. All patients underwent horizontal muscle recessions/resections for exotropia along with bilateral posterior tenectomy of the superior oblique with inferior oblique anterior transpositioning.

Results:

The median age was 10 years (Range 5–26 years). The mean postoperative follow-up was 26 ± 14.02 months (Range 12–48 months). The mean reduction in exotropia was from 36.5 ± 21.06 PD (Range 15–65 PD) to 6.1 ± 3.06 PD (Range 3–10 PD). The procedure corrected the A pattern from a mean 23 ± 7 PD (Range 15–35 PD) to 7.6 ± 3.2 PD (Range 3–10 PD). The average DVD in the right eye reduced from 14 ± 4.3 PD (Range 8–20 PD) to 5.3 ± 1.2 PD and in the left eye from 14.33 ± 3.6 PD (Range 10–18 PD) to 4.1 ± 1.1 PD. The DVD asymmetry reduced from 6.33 ± 3.4 PD to 1.5 ± 1.3 PD.

Conclusion:

”Four oblique” procedure with horizontal muscle surgery seems to be an effective method for significantly correcting the A pattern as well as reducing the DVD with good long-term outcome in our case series.

The effects of simultaneous operation on dissociated vertical deviation with horizontal and torsional strabismus

AIM

To investigate the therapeutic effects of simultaneous horizontal and vertical operations on dissociated vertical deviation (DVD) associated with other deviations.

METHODS

Forty-five cases of DVD with horizontal and torsional strabismus underwent combined operation were collected retrospectively. All clinical records were analyzed. All patients were followed up for 6 to 24mo. Wilcoxon signed-ranks test was performed to evaluate the changes of vertical and horizontal deviation. χ ² test was used to evaluate the changes of binocular visual function.

RESULTS

Forty-five cases included 36 patients with intermittent exotropia and binocular inferior oblique overaction (IOOA), 5 patients with concomitant esotropia and binocular IOOA, 4 patients with intermittent exotropia and monocular superior oblique palsy. The superior rectus recession (SRR) combined with horizontal rectus recession and the myectomy of inferior oblique or anterior transposition were operated simultaneously to correct all types of strabismus. There were 43 cases who achieved normal eye position in vertical direction, while 2 cases were with undercorrection of 5^Δ to 6^Δ. In patients with horizontal strabismus, 2 cases of exotropia were with overcorrection of 6^Δ to 8^Δ, 1 case of esotropia was with undercorrection of 6^Δ, and 1 case of monocular superior oblique palsy with compensatory head posture was not significantly improved. The binocular visual function of most patients recovered after operation. The difference of the binocular visual function and eye position were significant compared with that before operation (P<0.05).

CONCLUSION

The simultaneous operation on DVD with horizontal and torsional strabismus is successful.

The stability of horizontal ocular alignment of triad exotropia after one-step triple surgery

PURPOSE

A-pattern exotropia, superior oblique muscle overaction, and dissociated vertical deviation may coexist and are referred to as triad exotropia. The present study evaluated the postoperative stability of horizontal ocular alignment of triad exotropia and possible prognostic factors.

METHODS

Medical records of patients with triad exotropia who had one-step triple surgery of superior oblique muscle weakening, superior rectus muscle recession, and lateral rectus muscle recession were reviewed. The horizontal alignment and postoperative drift of triad exotropia were analyzed and compared with constant exotropia.

RESULTS

The triad exotropia showed a mean of 7.7^△ (± 8.5^△) eso-drift, while the constant exotropia was (3.5^△ ± 3.4^△) exo-drift. Multiple linear regression analysis showed that the degree of superior oblique muscle overaction after surgery (P = 0.011) was the only factor associated with horizontal drift. Patients with superior oblique muscle underaction showed larger eso-drift when compared to patients without superior oblique muscle underaction (- 18.0^△ ± 11.1^△ vs. - 5.1^△ ± 5.7^△; P = 0.024). The final success rates of the triad exotropia and constant exotropia groups were 53.3% and 69.2%, respectively, and the overcorrection rates were 26.7% and 2.6% (P = 0.035).

CONCLUSIONS

An overall trend of eso-drift in primary position occurred in triad exotropia after triple surgery up to a follow-up of 25 months. Patients presenting superior oblique muscle underaction after surgery seemed to have large angles of eso-drift, which might be taken into account in surgical planning and follow-up.

Repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography macular metrics in healthy subjects

Purpose

To investigate the repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography (SS-OCTA) metrics in healthy subjects.

Methods

Thirty-three healthy normal subjects were enrolled. The macula was scanned four times by an SS-OCTA system using the 3 mm×3 mm mode. The superficial capillary map images were analysed using a MATLAB program. A series of parameters were measured: foveal avascular zone (FAZ) area, FAZ perimeter, FAZ circularity, parafoveal vessel density, fractal dimension and vessel diameter index (VDI). The repeatability of four scans was determined by intraclass correlation coefficient (ICC). Then the averaged results were analysed for intereye difference, correlation and agreement using paired t-test, Pearson’s correlation coefficient (r), ICC and Bland-Altman plot.

Results

The repeatability assessment of the macular metrics exported high ICC values (ranged from 0.853 to 0.996). There is no statistically significant difference in the OCTA metrics between the two eyes. FAZ area (ICC=0.961, r=0.929) and FAZ perimeter (ICC=0.884, r=0.802) showed excellent binocular correlation. Fractal dimension (ICC=0.732, r=0.578) and VDI (ICC=0.707, r=0.547) showed moderate binocular correlation, while parafoveal vessel density had poor binocular correlation. Bland-Altman plots showed the range of agreement was from −0.0763 to 0.0954 mm2 for FAZ area and from −0.0491 to 0.1136 for parafoveal vessel density.

Conclusions

The macular metrics obtained using SS-OCTA showed excellent repeatability in healthy subjects. We showed high intereye correlation in FAZ area and perimeter, moderate correlation in fractal dimension and VDI, while vessel density had poor correlation in normal healthy subjects.

Two cases of hypotropia and dissociated vertical deviation treated with oblique muscle surgery

The authors report two cases with vertical deviations. The first patient had right exotropia and hypotropia and left inferior oblique overaction and was treated with left inferior oblique muscle weakening and bilateral lateral rectus muscle recession. The second patient had chin-up posture and right dissociated vertical deviation and was treated with bilateral superior oblique posterior tenotomy.

Asymmetric inferior oblique anterior transposition for incomitant asymmetric dissociated vertical deviation

BACKGROUND

Inferior oblique anterior transposition (IOAT) is indicated in patients with incomitant dissociated vertical deviation (DVD) larger in adduction. In general, bilateral surgery is recommended in patients with DVD unless there is deep monocular amblyopia. The purpose of this study is to evaluate the results of asymmetric IOAT in patients with asymmetric incomitant DVD larger in adduction.

METHODS

Retrospective chart review of the records of all patients with incomitant asymmetric DVD associated with inferior oblique (IO) overaction who underwent asymmetric IO weakening procedure. In all patients, the eye with more DVD in adduction underwent IOAT to the temporal corner of the insertion of the inferior rectus (IR) muscle, and the eye with less DVD underwent IOAT to a position 3-4 mm posterior to the insertion of the IR. No other muscles were operated simultaneously. No patient had previous surgery on any cyclovertical extracular muscle.

RESULTS

Fourteen patients were included. Mean age at surgery was 10.3 ± 8.8 years (range 4-33). Primary position DVD preoperatively was 18 ± 2 PD in the eye with the larger DVD compared to 1.1 ± 1.0 PD postoperatively (p < 0.0001). DVD asymmetry between the lateral gaze with the largest DVD and the lateral gaze with the smallest DVD was 9.8 ± 3.1 PD (range 5-14 PD) preoperatively vs 1.1 ± 1.0 PD (range 0-2 PD), (p < 0.0001). Ten patients had preoperative V-pattern >10 PD (24.7 ± 8.7 PD, range 12-50 PD) preoperatively vs no patients postoperatively (mean V-pattern 4.4 ± 2.0 PD), (p < 0.0001). Postoperative follow up was 1.6 ± 0.7 years (range 1-3 years).

CONCLUSION

In patients with asymmetric incomitant DVD, asymmetric IOAT improves lateral incomitance without increasing the risk of antielevation, limitation in upgaze rotation, or hypertropia, or worsening the DVD in the eye with less deviation preoperatively.

Contralateral superior oblique posterior tenotomy (SOPT): a primary treatment for diplopia in downgaze following blowout orbital fracture

PURPOSE

Superior oblique posterior tenotomy (SOPT) is a recognized surgical treatment to weaken the depressor effect of the superior oblique muscle without causing excyclotropia. We analyzed its use in the management of diplopia in downgaze due to contralateral blowout orbital fracture.

METHODS

We performed a retrospective case note review of patients that had undergone an SOPT as a primary surgical option in the management of diplopia in down gaze caused by contralateral blowout orbital fracture. The study covered a 17-year period from 1993 and 2010. These cases had diplopia maximal to the side of the orbital blowout. Pre- and postoperative orthoptic measurements were compared. Surgical complications were noted.

RESULTS

Five patients who fulfilled the entry criteria were identified. The mean follow-up period was 15.2 months (range 6-20 months). Preoperatively, the median |dev| was 2 prism diopters (PD) in primary position (range, 0-2) and 8 PD in downgaze (range, 2-18). At the final follow-up, the median |dev| in primary position was 0 PD (range, 0-2) and 2 PD in downgaze (range, 0-12). There were no significant differences pre- and postoperatively in both the primary position (p=0.19) or in downgaze (p=0.25) despite the large reduction in deviation size. Two patients needed a second procedure following SOPT. No patients complained of torsion, not in the primary position or in downgaze following the surgery.

CONCLUSION

Contralateral SOPT can be a useful and simple primary treatment option for patients with moderate vertical deviations in downgaze to the same side of the orbital fracture. Larger deviations may require second surgeries. SOPT does not cause iatrogenic excyclotorsion and avoids surgery to a potentially much scarred inferior rectus area.