Anterior transposition of inferior oblique muscle for treatment of unilateral superior oblique muscle palsy with inferior oblique muscle overaction

Inferior oblique anterior transposition according to a grading scale for hyperdeviation with inferior oblique overaction

OBJECTIVE

To define an inferior oblique anterior transposition (IOAT) grading scale in patients with hyperdeviation and inferior oblique overaction (IOOA), which we planned based on the data we obtained in our previous retrospective study.

DESIGN

Prospective cohort study.

PARTICIPANTS

Thirty-eight patients who underwent graded IOAT.

METHODS

The patients were divided into 5 groups according to the amount of hyperdeviation in the primary position (PPHD). The inferior oblique muscle was transposed 2 mm posterior, 1 mm posterior parallel, 1 mm anterior, and 2 mm anterior to the inferior rectus insertion, respectively. Surgical success was defined as success (PPHD ≤3 PD), partial success (PPHD >3 and ≤6 PD), and nonsuccess (PPHD >6 PD).

RESULTS

The mean amount of hyperdeviation correction in groups after IOAT was 9.50 ± 0.9 PD (range, 8-10 PD), 12.43 ± 1.5 PD (range, 11-14 PD), 16.67 ± 1.4 PD (range, 15-18 PD), 19.57 ± 1.7 PD (range, 16-21 PD), and 22.57 ± 5.8 PD (range, 14-30 PD), respectively. Surgical success was achieved in 34 patients (89.5%) after surgery, partial success was achieved in 3 patients (7.9%), and nonsuccess was observed in 1 patient (2.6%). All patients in our study had unilateral IOOA preoperatively, and IOOA developed in the contralateral eye of 9 patients (23.7%) during postoperative follow-up. In group 5, 4 patients (57.1%) developed -2 upgaze limitation, but surgery was not required.

CONCLUSIONS

A high success rate can be achieved with this grading of IOAT in primary and secondary IOOA cases accompanying hyperdeviation in the primary position.

Inferior Oblique Muscle Overaction: Clinical Features and Surgical Management

Purpose

To further define the clinical features of patients with inferior oblique muscle overaction (IOOA) and evaluate the surgical results in a subgroup of these patients.

Methods

The medical records of 173 patients who underwent inferior oblique muscle (IO) weakening surgery due to primary or secondary IOOA were retrospectively reviewed. The patients were assigned a surgical group based on severity of IOOA and presence of dissociated vertical deviation (DVD) or hypertropia. Patients with +1 or +2 IOOA underwent recession, patients with +3 or +4 IOOA underwent myectomy, and patients with any grade of IOOA and DVD or hypertropia underwent anterior transposition (AT) surgery.

Results

A total of 286 eyes of 173 patients who underwent surgery due to IOOA were included in the study. IOOA was accompanied by esotropia, exotropia, abnormal head posture (AHP), pattern strabismus, convergence insufficiency, DVD, facial asymmetry, and nystagmus. The most common comorbid disorder was esotropia. The recession was used in 173 eyes, myectomy in 64, and AT in 49. Surgical success was obtained in 96.0% of eyes that underwent recession, in 98.4% of eyes that underwent myectomy, and in 93.9% of eyes that underwent AT. In the follow-up, IOOA occurred in the fellow eye in 36.1% of patients who underwent unilateral surgery.

Conclusions

This study is a comprehensive report on the concomitants of the IOOA. Also, it showed that all of the three surgical procedures including recession, myectomy, and AT are effective in the surgical management of IOOA when performed in select patient groups.

When is Isolated Inferior Oblique Muscle Surgery an Appropriate Treatment for Superior Oblique Palsy?

Purpose

To evaluate the efficacy of isolated inferior oblique muscle weakening in the treatment of superior oblique palsy.

Methods

Forty-seven patients with superior oblique palsy underwent either single-muscle surgery (anteriorization or recession of the inferior oblique muscle) or two-muscle surgery (anteriorization of the inferior oblique muscle combined with recession of the contralateral inferior rectus muscle according to the amount of vertical deviation). In a retrospective non-comparative study the objective surgical effect was calculated as the difference between the deviation at the day before surgery and the deviations 6 weeks and at least 1 year after surgery. Pre- and postoperative sensorimotor status and subjective outcome were evaluated.

Results

In patients who underwent isolated inferior oblique muscle surgery the mean preoperative vertical deviation decreased from 15±9 (distance)/16±10 (near) prism diopters (PD) (anteriorization) and 7±5 (distance)/9±8 (near) PD (recession) to 4±4 (distance)/4±6 (near) PD (anteriorization) and 2±2 (distance)/2±3 (near) PD (recession) at the 1-year follow-up. In patients who underwent two-muscle surgery the mean vertical deviation decreased from 20±11 (distance)/21±10 (near) PD preoperatively and 6±7 (distance)/6±6 (near) PD at 1-year follow-up. Subjective assessment showed excellent scores among the patients treated with single-muscle surgery and slightly lower but also favorable scores among the patients treated with combined techniques. A direct comparison of the different outcome scores was not possible because of the more difficult initial situation in patients who underwent combined surgery.

Conclusions

Isolated inferior oblique muscle weakening is an effective treatment option for superior oblique palsy up to 15 PD of vertical deviation in primary position. Two-muscle surgery should be reserved for patients with larger vertical deviations.

Managing Hypoplasia of the Inferior Rectus Muscle by Inferior Oblique Anterior Transposition in Children

Congenital hypoplasia or aplasia of the inferior rectus muscle is an uncommon condition. The authors present two pediatric patients with hypoplasia of the inferior rectus muscle treated by inferior oblique anterior transposition. The long-term follow-up outcomes of eye position and stereopsis acuity development were favorable. [J Pediatr Ophthalmol Strabismus. 2017;54:e50-e53.].

Combined resection and anterior transposition of the inferior oblique muscle for treatment of large primary position hypertropia caused by unilateral superior oblique muscle palsy

PURPOSE

To evaluate the efficacy of combined resection and anterior transposition of the inferior oblique muscle for treatment of unilateral superior oblique muscle palsy with hypertropia from 20(Δ) to 25(Δ) in primary position.

METHODS

The medical records of consecutive patients operated on for unilateral superior oblique muscle palsy and hypertropia from 20(Δ) to 25(Δ) in primary position were retrospectively reviewed. All patients had overaction of the inferior oblique muscle. The inferior oblique muscle was disinserted and 4 mm of its distal end was resected and transposed to the lateral border of the inferior rectus muscle insertion. The prism and alternate cover test was used to measure hypertropia. Surgical results were evaluated at 6 months' follow-up.

RESULTS

A total of 27 patients were included. The mean hypertropia in primary position was 22.6 ± 0.4(Δ) preoperatively, which decreased to 1.4 ± 0.6(Δ) after surgery. None of the patients developed hypotropia in primary position. Mild limitation of elevation was recorded in 1 patient, and 4 patients developed lower eyelid fullness.

CONCLUSIONS

In this patient cohort, combined resection and anterior transposition of the inferior oblique muscle effectively treated unilateral superior oblique muscle palsy with hypertropia from 20(Δ) to 25(Δ) in primary position.

Abnormal expression of seven myogenesis-related genes in extraocular muscles of patients with concomitant strabismus

Hyperplasia or hypoplasia of muscles gradually leads to strabismus. Myogenesis-related genes are involved in extraocular muscle development, including myogenic differentiation 1 (MYOD1), myogenin (MYOG), retinoblastoma 1 (RB1), cyclin-dependent kinase inhibitor 1A (P21), cyclin‑dependent kinase inhibitor 1C (P57), insulin-like growth factor 1 (IGF1) and muscle creatine kinase (MCK). This study evaluated the expression of the above seven myogenesis-related genes by real-time quantitative RT-PCR in 18 resected extrocular muscles of patients with concomitant strabismus and 12 normal control muscle samples from one presumably healthy male 6 h after sudden mortality. We found that although there was a great divergence among the expression levels of 6 myogenesis-related regulatory factors, the relative expression patterns were similar in all the normal muscles, including the synergistic, antagonistic and yoke muscles. However, their expression levels in the 18 diseased extraocular muscles were abnormal; the expression levels of all the genes, with the exception of P57, were reduced in most of the diseased muscle tissues. These results imply that the abnormal expression of these myogenesis-related genes may contribute to concomitant strabismus.

Residual symptoms after surgery for unilateral congenital superior oblique palsy

PURPOSE

To establish the surgical results and residual symptoms in 48 cases with unilateral congenital superior oblique muscle palsy that had surgical intervention to the vertical muscles alone.

METHODS

Myectomy and concomitant disinsertion of the inferior oblique (IO) muscle was performed in 38 cases and myectomy and concomitant IO disinsertion and recession of the superior rectus muscle in the ipsilateral eye was performed in 10 cases. The preoperative and postoperative vertical deviation values and surgical results were compared.

RESULTS

Of the patients who had myectomy and concomitant IO disinsertion, 74% achieved an "excellent" result, 21% a "good" result, and 5% a "poor" result postoperatively. The difference in deviation between preoperative and postoperative values was statistically significant (P < .001). Of the patients who had myectomy and concomitant inferior oblique disinsertion and ipsilateral superior rectus recession, 50% achieved an "excellent" result, 20% a "good" result, and 30% a "poor" result postoperatively. The difference in deviation between preoperative and postoperative values was statistically significant (P < .001).

CONCLUSION

Both procedures are effective and successful in patients with superior oblique muscle palsy, but a secondary surgery may be required.

Anterior transposition of the inferior oblique muscle in the treatment of unilateral superior oblique palsy

PURPOSE

To determine whether unilateral inferior oblique anterior transposition alone could be an effective procedure for treating superior oblique palsy with inferior oblique overaction.

METHODS

The records of 38 patients who underwent unilateral inferior oblique anterior transposition for unilateral superior oblique palsy with inferior oblique overaction were evaluated. A comprehensive ocular examination including best-corrected visual acuity measurements, ductions, versions, and deviations at near and distance, head tilt test, abnormal head position, dilated fundus examination, and Titmus test was performed prior to and after surgery.

RESULTS

The mean patient age was 29 years, the mean follow-up was 32 months, the mean preoperative hypertropia in primary position was 14.29 ± 7.7 prism diopters (PD), and the mean inferior oblique overaction was 3.63 ± 0.67. Anterior transposition of the inferior oblique muscle was effective across a wide range of preoperative primary position hypertropia (4 to 35 PD) with a mean reduction in postoperative hypertropia of 12 PD. Inferior oblique overaction was reduced in all patients. No patient demonstrated postoperative primary position hypotropia. Surgery improved stereoacuity nearly two units using the Titmus stereoacuity scale.

CONCLUSION

Anterior transposition of the inferior oblique muscle is effective in correcting inferior oblique overaction and primary position hypertropia in the treatment of unilateral superior oblique palsy.

Effectiveness of disinsertion-resection and tucking of the inferior oblique muscle in patients with unilateral long-standing superior oblique muscle palsy

PURPOSE

To investigate the effectiveness and safety of disinsertion-resection and tucking of the inferior oblique muscle in patients with unilateral long-standing superior oblique muscle palsy and secondary inferior oblique muscle overaction.

METHODS

Between April 2000 and January 2005, the records of 31 patients who underwent disinsertion-resection and tucking of the inferior oblique muscle for treatment of unilateral long-standing (> 6 months) superior oblique muscle palsy were retrospectively reviewed. A comprehensive ocular examination including best-corrected visual acuity measurements, ductions, versions, and deviations at near and distance in the diagnostic positions of gaze, head tilt test, abnormal head position, dilated fundus, field of binocular fixation, and Lee screen test was performed prior to and after surgery.

RESULTS

All patients had Knapp's class I unilateral superior oblique muscle palsy. The mean preoperative score of inferior oblique muscle overaction was +3.03 and the mean vertical deviation was 15.9 PD in primary position. The follow-up period ranged from 4 to 82 months. Inferior oblique muscle overaction diminished in 29 patients, and 2 patients had +1.0 overaction in adduction of the affected eye. The vertical deviation in these patients had some residual but smaller hypertropia.

CONCLUSIONS

Disinsertion-resection and tucking of the inferior oblique muscle was safe, simple, and effective in eliminating inferior oblique muscle overaction and abnormal head posture, and in reducing the hyperdeviation in patients with unilateral long-standing superior oblique muscle palsy.

Inferior oblique muscle fixation to the orbital wall: a profound weakening procedure

INTRODUCTION

Recurrent or persistent inferior oblique overaction may occur after inferior oblique (IO) recession or anterior transposition. IO nasal and temporal myectomy and anterior-nasal transposition may result in undesirable IO palsy, exotropia, incyclotorsion, or limitation of elevation. Previous studies have shown that a rectus extraocular muscle may be profoundly weakened if the muscle insertion is reattached to adjacent orbital periosteum. We describe a reversible profound weakening surgical procedure of the IO muscle.

METHODS

A total of 10 consecutive subjects with V-pattern strabismus and/or IO overaction underwent IO orbital fixation procedure by attaching its insertion to the periosteum of the lateral orbital wall. One subject was not included because short follow-up. Five subjects with persistent IO overaction after IO anterior transposition underwent bilateral IO orbital wall fixation. Four subjects with no previous IO surgery underwent unilateral IO orbital wall fixation; 3 of these 4 subjects had superior oblique palsy with a large vertical deviation in primary position and 1 had a V pattern with asymmetric IO overaction.

RESULTS

V pattern significantly improved from 22(Delta) preoperatively to 7(Delta) postoperatively (p = 0.002). IO overaction improved from 2.5 (range, + 1.5 to + 4) to 0.1 (range, -2 to +3) postoperatively (p < 0.001). Six of 9 subjects had no residual overelevation in adduction postoperatively. Unilateral IO orbital fixation corrected 7(Delta) of vertical deviation in the primary position and 23(Delta) in adduction. Mean postoperative follow-up was 5 months.

CONCLUSIONS

IO orbital fixation has a profound weakening effect on the IO muscle. Advantages of this procedure include reversibility and that it can be converted into another form of weakening procedure, if required.