Antielevation Syndrome Research Articles

Clinical outcomes of inferior oblique myectomy in age categorized patients with unilateral superior oblique palsy

BackgroundUnilateral superior oblique palsy (SOP) is the most common isolated cranial nerve palsy. This report looks at the results and safety of inferior oblique (IO) myectomy for SOP. MethodsA retrospective chart review of patients with fusional ability who underwent IO myectomy for unilateral SOP over a 15-year period, at one of our university-associated health care centers. Primary outcomes were: distance hypertropia and excyclotropia in primary position, inferior oblique overaction (IOOA) and the correlation between the age at surgery and the residual distance hypertropia. ResultsA total of 73 patients with unilateral SOP who underwent IO myectomy were included in the analysis. Mean pre-operative values were: distance hypertropia: 15.41 ± 6.8 Prism Diopters (range 4–30 PD), IOOA: +2.2 ± 0.7 (range 0–3.5) and excyclotropia: +5.34 ± 3.6° (range 0–12°). Mean post-operative values were: distance hypertropia: 3.7 ± 3.4PD [0-14PD], IOOA: −0.1 ± 0.8 [(-2)-2] and excyclotropia: +1.1 ± 2.3°[(-5)-10]. The younger age group (0–20 years old) had a trend toward smaller preoperative distance hypertropia (P = 0.051), and a significantly smaller distance hypertropia post-operatively (p = 0.007). There was no case of ocular complication. ConclusionsOn average, IO myectomy results in a 11.7PD reduction of the distance hypertropia, and 4° reduction of excyclotropia, with an effective reduction of IOOA. While these results are comparable to other surgical methods reported in the literature, they underline an efficacy without the risks of complications such as anti-elevation syndrome and possible scleral perforation. The younger age group had a trend toward smaller preoperative deviation, and better outcomes compared to the older age group.

Anterior transposition of the inferior oblique and anti-elevation syndrome – how far to go?

ABSTRACT Purpose: To study the incidence of postoperative anti-elevation syndrome in relation to the magnitude of anterior transposition of the inferior oblique. Methods: A retrospective chart review was conducted for all patients submitted to anterior transposition of the inferior oblique from 2000 to 2020. Anti-elevation syndrome was defined as limitation of elevation of the abducting eye, resulting in a secondary upshoot of the contralateral adducting eye. Results: A total of 312 eyes of 170 patients were enrolled in the study. The incidence of anti-elevation syndrome was 20.4% when the inferior oblique was positioned 4 mm posterior to the temporal border of the inferior rectus insertion; 23.5% when sutured 2 mm posterior to the temporal border of the inferior rectus insertion and 32.8% when placed at the same level of the inferior rectus insertion with two sutures vertically aligned. When the posterior border of the inferior oblique was horizontally aligned with the anterior border and positioned adjacent to the inferior rectus insertion, in a “J shape” fashion, the incidence of anti-elevation was 41.8%. Conclusions: The anterior transposition of the inferior oblique with “J” deformity increases the risk of anti-elevation syndrome. Additionally, placing the sutures more anteriorly than 2 mm posterior to the inferior rectus insertion increases the incidence of this finding.

Surgical Outcome of Inferior Oblique Myectomy versus Recession-Anteriorization in the Treatment of Inferior Oblique Overaction.

This study aimed to compare the surgical outcome of inferior oblique myectomy, IOM versus inferior oblique recession-anteriorization, IORA in the treatment of inferior oblique overaction, IOOA. A retrospective chart review was performed over a 12-year period, from 2009 to 2021. Eighty-nine patients diagnosed with IOOA who underwent IOM or IORA were included. The primary outcome was postoperative residual IOOA (grade 0 to +4) and percentage favorable outcome, defined as IOOA grade ≤1+ at 6 months post operation, in each group. The outcomes were compared between the two surgical procedures (IOM and IORA). The secondary outcome was the percentage of postoperative anti-elevation syndrome cases for each surgical procedure. The median age at the time of surgery was 10.50 years (interquartile range, IQR: 2.83 to 28.33) in the IOM group and 5.08 years (IQR: 2.75 to 29.42) in the IORA group. The favorable outcome at 6 months was 90.91% in the IOM group, which was lower than the 95.74% in the IORA group but the difference was not statistically significant (P-value = 0.390, 95% CI: 0.07-2.82). The only surgical complication, anti-elevation syndrome, was detected in 3.77% of IOM cases and 5.80% of IORA cases, with an odds ratio of 0.64 on comparing the IOM group to the IORA group (P-value = 0.611, 95% CI: 0.11-3.62). These two weakening procedures are effective for treating IOOA. Although IORA seemed slightly superior to IOM in terms of favorable outcomes, the difference was not statistically significant. Moreover, the myectomy procedure was easier, was less time-consuming, had a lower risk of globe perforation and presented fewer complications such as anti-elevation syndrome.

Long-Term Efficacy of Inferior Oblique Myectomy Accompanied with Tenon’s Capsule Closure: Objective Analysis Using Nine-Gaze Photographs

Background: The aim is to evaluate the long-term efficacy of inferior oblique (IO) myectomy combined with Tenon's capsule closure to prevent muscle reattachment to the sclera. Methods: We retrospectively reviewed the medical records of 18 patients with primary and secondary IO overaction who underwent IO myectomy accompanied by Tenon's capsule closure. Patients were followed up for at least 1 year after the surgery. The main outcome measures included oblique muscle dysfunction, which was objectively graded through computerized analysis of nine-gaze photographs, and the amount of vertical deviation in the primary position using alternate prism cover testing. Results: After a mean follow up of 2.5 years, the grade of IO overaction decreased from +2.2 ± 1.0 to -0.8 ± 1.0 (p < 0.001). In patients with secondary IO overaction with superior oblique (SO) palsy, SO underaction improved from -2.2 ± 1.5 to -0.2 ± 1.8 (p = 0.006). Successful vertical deviation in the primary position of seven prism diopters or less was achieved in 83.3% of the patients. Underaction of the IO was observed in 11.1% of patients, whereas none of the patients showed antielevation syndrome. Conclusion: IO myectomy combined with Tenon's capsule closure might be safe and effective for the treatment of primary and secondary IO overaction in the long term.

Inferior Oblique Anterior Transposition versus Myectomy for Inferior Oblique Overaction: Systematic Review and Meta Analysis.

The objective of this study was to compare the outcomes of inferior oblique anterior transposition (IOAT) versus inferior oblique myectomy (IOM) in patients with primary inferior oblique overaction (IOOA) or secondary IOOA to superior nerve palsy. A systematic review and meta-analysis were performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines and an electronic search was conducted to identify studies comparing IOAT versus IOM for IOOA. Residual inferior oblique function, reduction in hypertropia and post-operative complications were identified as primary outcomes. Secondary outcomes included superior oblique function, head tilt improvement, effect on the contralateral eye, operation time and macular changes. The analysis was based on fixed or random-effects modelling. Eleven studies enrolling 729 patients were identified. Inferior oblique function was not significantly different between both interventions, namely the elimination of IOOA (Odds Ratio[OR] = 0.97, P = 0.97), reduction in IOOA (Mean Difference[MD] = -0.06, P = 0.68), post-operative inferior oblique under-action (OR = 1.06, P = 0.83) and residual overaction (OR = 0.71, P = 0.15). Similarly, no significant difference was noted between both groups in reducing hypertropia. Regarding post-operative complications, no significant difference was observed, including the incidence of anti-elevation syndrome (P = 0.10). No significant difference was noted regarding superior oblique function, improvement in head tilt, effect on the contralateral eye and macular changes, although surgical time was shorter in the IOM group. In conclusion, IOAT and IOM are both effective surgical procedures in the management of IOOA as they produced comparable outcomes in the improvement in hypertropia, post-operative inferior oblique function and incidence of complications.

Novel Inferior Oblique Muscle Y Splitting Procedure to Minimize the Anti-Elevation Syndrome: A Pilot Study.

PurposeTo describe novel Y splitting procedure of inferior oblique muscle to mitigate the anti-elevation syndrome.MethodsA pilot, prospective interventional study was undertaken to assess the effect of inferior oblique muscle Y-splitting in patients with unilateral 3+ or more overaction. To correct primary gaze hypertropia and the excyclotorsion, a Y-splitting procedure was performed (along with routine horizontal muscle surgery as per the deviation) in 14 subjects. The effect of surgery was assessed at baseline and at 6 months post-intervention.ResultsThe mean age of 14 subjects was 25.14±7.70 years. The mean pre-operative hypertropia, excyclotorsion and inferior oblique muscle over-action was 18.42±3.50 PD, 14.14±2.65 degrees, and +3.21±0.42 respectively. Following surgery, this was reduced to 1.57±1.74 PD of residual hypertropia (a net correction of 16.85±2.31 PD, p = 0.005), 3.85±1.46 degrees of residual excyclotorsion (a net correction of 10.28±1.72 degrees, p < 0.05), and +0.28±0.46 of residual inferior oblique over-action (a net correction ~+3) at the end of 6 months. Amongst fourteen patients, three patients still experienced residual/variable anti-elevation effect, and during the study period none of them experienced any adverse event and none of them required any additional surgeries.ConclusionWhile anteriorizing the inferior oblique muscle to correct primary gaze hypertropia and the excyclotorsion, a novel “Y splitting” procedure can be followed to achieve the desired results with mitigated anti-elevation effect.

Effect of bilateral inferior oblique partial myectomy on V pattern exotropia with inferior oblique overaction

PurposeTo compare the effect of bilateral inferior oblique partial myectomy on V-pattern exotropia patients with bilateral symmetric inferior oblique overaction (IOOA) and asymmetric IOOA.MethodsThis was a retrospective study including 53 V-pattern exotropia patients with bilateral IOOA of all grades who underwent bilateral inferior oblique partial myectomy. Success was defined as the elimination of the IOOA and the collapse of the V pattern at the final follow-up. The fovea-disc angle (FDA) and V-pattern exotropia were compared before and after surgery.ResultsThis study included 53 V-pattern exotropia patients, containing 29 patients with symmetric IOOA (Group I) and 24 patients with asymmetric IOOA (Group II). The last follow-up ranged from 3 to 16 months (mean of 5 months). After myectomy, 3 eyes in Group I and 2 eyes in Group II were observed with residual grade 1 IOOA. The surgical success rates of IOOA correction in Group I and Group II were 96% and 95%, respectively. The difference was not statistically significant (P = 0.808). V-pattern exotropia collapsed with residual 2 (min. 0, max. 6) PD for Group I and 2 (min. 0, max. 10) PD for Group II, and there was a statistically significant difference between pre- and postoperative V-pattern exotropia in the two groups (P = 0.000). No inferior oblique (IO) underaction or antielevation syndrome (AES) was found in either group. The average preoperative FDA of the right eye and the left eye was (8.93 ± 4.34)° and (10.86 ± 4.27)° in Group I and (9.08 ± 4.92)° and (11.00 ± 5.69)° in Group II. There was a significant difference in preoperative FDA between the right eye and the left eye in the two groups (Group I p = 0.029; Group II p = 0.038).ConclusionsBilateral inferior oblique partial myectomy can bring “symmetric” effectiveness in the correction of IOOA and FDA. It can potentially be used as a safe and successful treatment for V-pattern exotropia with bilateral IOOA. In addition, the FDA may be a promising index for evaluating fundus extorsion.

Effect of inferior oblique muscle belly transposition on versions and vertical alignment in primary position.

To evaluate the effect of inferior oblique muscle belly transposition (IOBT) on vertical deviation (VD) in primary position and inferior oblique overaction (IOOA). Twenty-eight patients who underwent unilateral IOBT for mild hypertropia (≤ 10△) due to unilateral IOOA were included. Surgical results regarding the correction of hypertropia, IOOA, and fovea disc angle (FDA) were analyzed and compared between groups A (VD ≤ 5△) and B (5△ < VD ≤ 10△). IOBT showed an overall reduction of 5.86△ (± 2.24△) of primary position VD, a mean correction of 1.00 (± 0.27) of IOOA, and an average change of 1.83° (± 3.02°) of FDA. The surgical success rate of IOBT for VD correction and IOOA elimination in all patients was 68% and 71%, respectively. The correction of VD was correlated with preoperative VD significantly (r = 0.86, p < 0.001). Consistently, IOBT demonstrated comparable efficacy in reduction of VD between group A and group B (p = 0.507). Furthermore, the two groups were comparable in the success rates for correcting VD and IOOA (both p > 0.05). None of the patients developed consecutive hypotropia, postoperative contralateral IOOA, or anti-elevation syndrome postoperatively. IOBT achieved satisfactory outcomes in patients with mild primary position VD (≤ 10△) that is associated with unilateral IOOA, without any risk of overcorrection of VD and contralateral IOOA for a follow-up period of up to 12months. This procedure is considered effective and safe alternative for weakening the IO in patients with appropriate surgical indications.

Efficacy of isolated inferior oblique anteriorization on large-angle hypertropia associated with unilateral superior oblique palsy

To evaluate the results of inferior oblique anteriorization for the treatment of large-angle hypertropia secondary to superior oblique palsy and to determine predictors of success and the occurrence of antielevation syndrome. In this prospective study, 25 patients with unilateral congenital and acquired superior oblique palsy who had a primary position hypertropia of at least 25Δ underwent inferior oblique anteriorization in the paretic eye. Postoperative changes in vertical deviation of primary position and contralateral gaze, abnormal head posture, extorsion, associated horizontal deviation, inferior oblique overaction, superior oblique underaction, and elevation in abduction were examined. Surgical success was defined as residual hypertropia in primary position of ≤4Δ at final examination. The mean age of patients at surgery was 19.8±11.9years (range, 4-49). The mean preoperative deviation in the primary position was 27.6Δ ± 3.2Δ; in contralateral gaze, 35.0Δ ± 3.8Δ; these measurements decreased postoperatively to 4.7Δ ± 5.6Δ and 7.0Δ ± 5.5Δ, respectively, after a median follow-up of 8months. The success rate was 72%, with no difference between patients with a preoperative deviation of 25Δ-29Δ and those with deviation of 30Δ-35Δ. In a multivariate logistic regression, preoperative extorsion was negatively related to success (OR=8.01; P=0.03). At the final follow-up, 4 patients (16%) showed antielevation syndrome and were clinically asymptomatic. In unilateral superior oblique palsy, one-muscle surgery, including inferior oblique anteriorization, can be conducted to resolve large-angle hypertropia of >25Δ. Excyotorsion is a risk factor that increases the likelihood of failure.

Surgical outcomes of three different weakening procedures of inferior oblique muscle in the treatment of unilateral superior oblique palsy

BackgroundTo compare surgical outcomes and complications of three inferior oblique weakening procedures; Inferior Oblique Myectomy (IOM), Inferior Oblique combined Resection-Anterior Transposition (IORAT) and Inferior Oblique Anterior Transposition (IOAT) in the management of unilateral Superior Oblique (SO) palsy.MethodsRetrospective review of medical records of all patients with unilateral SO palsy who underwent one of the aforementioned IO weakening procedures at Benha University hospital was performed. Patients were excluded if surgery was bilateral or combined with other vertical muscle surgery. Primary outcome parameters were improvement of Hypertropia (HT) in primary gaze, side gazes, on alternate head turn, Inferior Oblique Overaction (IOOA), Superior Oblique Underaction (SOUA), correction of head tilt and postoperative complications.ResultsThe review reveals a total of 65 patients with unilateral SO palsy; 54 congenital and 11 acquired, who met the study criteria and were classified into 3 groups; IOM group (24cases), IORAT group (19cases) and IOAT group (22cases). Compared with IOM, both IORAT and IOAT induced significant correction of HT in primary position, ipsilateral gaze, contralateral head tilt and IOOA. IORAT was significantly more effective than IOAT in correction of HT in ipsilateral gaze and contralateral head tilt while there was no statistical difference between the three groups in correction of HT in ipsilateral gaze, contralateral head tilt and SOUA. Postoperative Anti-elevation was significantly recorded following IORAT (6 cases, 31%) than IOAT (3 cases, 13%) and IOM (one cases, 4%).ConclusionsThe IORAT and IOAT were more superior to IOM in correction of IOOA and HT in the primary position and some other gaze positions. However, superiority of IORAT over the other two procedures should be weighed against its significant association with postoperative underaction of IO muscle and anti-elevation syndrome.

Unilateral inferior oblique anterior transposition for markedly asymmetric dissociated vertical deviation with unilateral inferior oblique over-action

BackgroundTo evaluate the results of unilateral inferior oblique anterior transposition (IOAT) for markedly asymmetric dissociated vertical deviation (DVD) combined with inferior oblique over-action (IOOA).MethodsRetrospective chart review of the records of all patients with asymmetric DVD combined with unilateral IOOA in the non-dominant eye who received unilateral IOAT on the non-dominant eye. No other muscles were operated on simultaneously. The amount of DVD and IOOA were measured before and after the operation and statistically analysed.ResultsSeventeen patients were included. The mean age at surgery was 23.5 ± 8.4 (range 12–38) years old. The mean postoperative follow-up period was 15.7 ± 7.2 (range 6–32) months. The primary position DVD was 19.6 ± 5.4 (range 14–36) PD preoperatively and decreased significantly to 2.9 ± 2.0 (range 0–8) PD postoperatively (P < 0.01). Preoperatively, there were 2, 7, and 8 patients with + 1, + 2, and + 3 IOOA, respectively, and these were reduced from 2.4 ± 0.7 to 0.3 ± 0.4 postoperatively (P < 0.01). None of the patients were complicated obvious hypotropia, anti-elevation syndrome or IOOA in the contralateral eye.ConclusionsUnilateral IOAT was recommended in patients with asymmetric DVD coexists with unilateral IOOA.

A novel mechanism for apparent inferior oblique overactions (IOOA)

Over elevation of the adducted eye during versions (apparent IOOA) are seen in dissociated vertical deviations, orbital anomalies, Duane syndrome, antielevation syndrome, mechanical restriction of IR, pulley heterotopia and silent sinus syndrome. We present a novel mechanism for apparent IOOA.

Comparison Between Temporal Versus Nasal Anterior Transposition of the Inferior Oblique Muscle for Management of Dissociated Vertical Deviation with Inferior Oblique over Action: Two Years Follow Up

Background: anterior nasal transposition (ANT) is a relatively new procedure which can be used to eliminate inferior oblique over action. An advantage of this procedure over temporal anterior transposition is that it avoids ante-elevation syndrome. Objective: to compare anterior temporal transposition (ATIO) of the inferior oblique muscles versus anterior nasal transposition (ANT) in management dissociated vertical deviation (DVD) with inferior oblique muscle over action (IOOA). Patients and Methods: The study included 50 eyes of 28 patients with DVD of at least 10 prism dioptres ? in the eye involved. The patients were divided into two groups. Group A (25 eyes of 15 patients) managed by temporal anterior transposition (ATIO) of the inferior oblique muscles and Group B (25 eyes of 13 patients) managed by nasal anterior transposition (ANT) of the inferior oblique muscles. All patients were followed for at least 24 months postoperatively. The size of preoperative and postoperative angle of DVD, grade of IOOA preoperative and postoperative, need for repeated surgeries and complications were recorded and evaluated. Results: In group A the mean DVD angle was decreased in primary positions from 21.11±4.32 ? to 9.5 ±4.7 ? (P<0.001) and from 19.5±4.6 ? to 5.51 ±2.65? (P<0.001) in group B mean IOOA grade was decreased from +2.0 ±0.7 to +0.18±0.4 in group A (P<0.001) and from +2.5 ±0.7 to +0.1±0.5 (P<0.001) in group B. In group B, two patients developed hypotropia of 5 and 6 PD. Persistent IOOA (+1) was observed postoperatively in two eyes in each group. Limited elevations in abduction developed in 3 patients in group A, the incidence of recurrence rate after 24 months was 2 eyes 10% in group A and one eye 5% in group B. Conclusion: Anterior transpositions either temporal or nasal of the inferior oblique muscles are safe and effective in management of DVD with inferior oblique muscle over action. Anterior nasal transposition (ANT) is more effective in correction of DVD with less incidence of antielevation syndrome and recurrence of DVD, however may induce persistent hypotropia.

Modified anterior transposition of the inferior oblique muscle

To introduce a modified method of anterior transposition of inferior oblique (ATIO) and compare with traditional method in terms of efficacy and complications. The medical records of patients who had undergone unilateral ATIO and were followed for at least 6months were reviewed retrospectively. The patients were divided into two groups according to the surgical method: modified ATIO (modified group, n=16) and traditional ATIO (traditional group, n=15). In modified ATIO, the anterior nasal fibers of the inferior oblique muscle were anchored to the sclera and the posterior temporal fibers were folded and buried under the fixed anterior nasal fiber of inferior oblique muscle. In the traditional method, both the anterior and posterior fibers were fixed with individual suturing. Postoperative change in vertical deviation and grade of inferior oblique overaction (IOOA) were analyzed. Complications, including antielevation syndrome, fat adherence syndrome, and lower lid deformity were assessed. Both modified and traditional methods effectively weakened the action of the inferior oblique muscle. The efficacy of the two methods did not differ in terms of change in vertical deviation (P=0.225) and grade of IOOA (P=0.169). Antielevation syndrome occurred more frequently in the traditional group than in the modified group (8/15 vs 2/16, resp. [P=0.019]). Incidences of fat adherence syndrome (0/15 vs 0/16 [P=1.0]) and lid deformity (3/15 vs 1/15 [P=0.678]) were not different. Modified ATIO was comparable to traditional ATIO in correcting vertical deviation and IOOA and had a lower risk of antielevation syndrome compared with traditional ATIO.

Infrequent Complications of Inferior Oblique Recession Surgery

ABSTRACTPurpose: To report the infrequent complications, including antielevation and adherence syndrome, after a unilateral and bilateral inferior oblique (IO) recession procedure and to discuss the possible causes. Methods: A retrospective chart review was conducted for patients on whom unilateral or bilateral IO weakening surgeries were performed. Results: Forty-three patients were included in the study. In 23 patients unilateral and in 20 patients bilateral IO weakening was performed. All patients underwent IO recession surgery. Mild limitation of elevation developed in two patients and adherence syndrome developed in one patient. All occurred after unilateral IO recession. No duction deficiency was observed in patients after bilateral IO recession. Conclusion: Antielevation and adherence syndrome can develop after unilateral IO recession surgery. Care should be taken not to tighten the neurofibrovascular bundle of the IO muscle during surgery.

Inferior Oblique Anterior Transposition in the Treatment of Upshoot in Duane Syndrome

Purpose: We report the procedure of inferior oblique anterior transposition (IOAT) in the treatment of upshoot in patients with Duane retraction syndrome (DRS). Methods: Two patients with DRS underwent surgery for severe up-shoot. For both patients, the inferior oblique (IO) was transposed to the temporal border of IO insertion. Approximately 64 months of periodic follow-ups for Case 1 and 7 months of periodic follow-ups for Case 2 were conducted. Results: After surgery, both patients showed a marked decrease in upshoot without noticeable anti-elevation syndrome. Conclusions: IOAT is an effective procedure in the treatment of significant upshoot in DRS

Surgical management of superior oblique paresis using inferior oblique anterior transposition.

Inferior oblique anterior transposition (IOAT) is an effective surgical procedure for weakening the inferior oblique muscle. The purpose of this study was to assess the effectiveness and complications of IOAT for superior oblique paresis at a single center over a period of 11 years. The medical records of consecutive patients treated for congenital and acquired fourth nerve paresis with IOAT procedures at Addenbrookes Hospital, Cambridge, from 2001 to 2012 were retrospectively reviewed. All patients were examined before and after surgery: the vertical deviation in primary position and on contralateral gaze was measured, as were versions. The data collected included patient sex and age, presenting complaint, follow-up period, abnormal head position before and after surgery, postoperative complications, and further operative procedures. A total of 98 IOAT procedures were reviewed, with a mean follow-up of 5.8 months. The technique produced a mean correction of 9.5(Δ) in primary position and 17(Δ) in contralateral gaze. Inferior oblique overaction was reduced in all cases, with 20% having a residual overaction and 47% having an underaction. No patients had symptomatic antielevation syndrome. In this patient cohort, IOAT effectively managed appropriately selected patients with superior oblique paresis, improving the vertical deviation in primary position and contralateral gaze. The procedure induced limitation of elevation in some patients. No patient experienced major postoperative symptoms.

Surgical management of long-standing antielevation syndrome after unilateral anterior transposition of the inferior oblique muscle

To investigate surgical management of patients with long-standing antielevation syndrome following unilateral anterior transposition of inferior oblique muscle. We present a series of 3 consecutive patients with significant hypotropia several years after unilateral anterior transposition surgery. An approach combining denervation-extirpation of the inferior oblique muscle and subsequent inferior rectus muscle recession and contralateral superior rectus muscle recession was used to manage all 3 patients. Denervation-extirpation surgery alone or with ipsilateral inferior rectus muscle recession were not enough to improve vertical misalignment in these patients. All 3 patients achieved successful results after denervation-extirpation surgery, ipsilateral inferior rectus muscle recession, and contralateral superior rectus muscle recession. In this case series, devervation-extirpation surgery on the inferior oblique muscle, ipsilateral inferior rectus recession, and contralateral superior rectus recession improved vertical misalignment in patients with long-standing antielevation syndrome after unilateral anterior transposition of the inferior oblique.

Modified Inferior Oblique Transposition Considering the Equator for Primary Inferior Oblique Overaction (IOOA) Associated with Dissociated Vertical Deviation (DVD)

Purpose: Inferior oblique anterior transposition (IOAT) should be done only in patients with inferior oblique overaction (IOOA) and dissociated vertical deviation (DVD) without fusional potential because the procedure can cause anti-elevation syndrome. This study reports the results of modified inferior oblique transposition onto the equator in 7 patients diagnosed with infantile exotropia or esotropia associated with IOOA and DVD.Methods: We performed modified inferior oblique (IO) transposition onto or considering the equator on 7 patients who had infantile exotropia or esotropia associated with IOOA and DVD. Five patients had infantile exotropia, and the other two patients had infantile esotropia. Six patients had undergone bilateral rectus -- Bilateral Lateral Rectus (BLR) or Bilateral Medial Rectus (BMR) -- recession previously and one patient underwent BLR recession and IO transposition simultaneously. They had more than +1.5 IOOA with DVD in both eyes. IO was transposed vertically onto the equator in this study. The mean distance between the lateral border of the inferior rectus insertion and the equator was 5.6 mm (range: 4.5 to 6.5 mm). Three months after the operation, degree of IOOA and DVD in each eye was evaluated.Results: IOOA and DVD were markedly reduced in all patients (+0.5 ∼+1 for IOOA postoperatively). Mild contralateral IOOA was noted but the motility disturbance was successfully corrected in all cases postoperatively.Conclusion: Bilateral IO transposition onto the equator could minimize antielevation and corrected IOOA and DVD successfully in patients with infantile exotropia or esotropia.

Inferior Oblique Transposition Onto the Equator: The Role of the Equator in Development of Contralateral Inferior Oblique Overaction

To investigate the role of the location of the equator and orientation of newly attached inferior oblique (IO) muscle in the development of contralateral inferior oblique overaction (IOOA). Fourteen patients (14 eyes) with 5 to 12 prism diopters (PD) of hyperdeviation in primary position with unilateral, congenital, superior oblique palsy were included. Seven patients underwent modified IO transposition onto the equator (equator group) and seven patients underwent modified IO 14-mm recession (14-mm group). IOOA in the contralateral eye and the angle of strabismus were assessed at 3 months postoperatively. Mean angles of hyperdeviation in primary gaze and sursoadduction were 0.7 and 2.1 PD in the equator group and 0.6 and 2.4 PD in the 14-mm group, respectively. Six patients (86%) developed anti-elevation syndrome and four patients (57%) showed definite 2+ or higher IOOA in the contralateral eye in the equator group. Three patients (43%) in the 14-mm group also developed contralateral IOOA, although it was 1+ or less. The postoperative difference in contra-lateral IOOA between groups was statistically significant (P = .04). This finding suggests that vertical orientation of the IO muscle is another important contributor in the development of contralateral IOOA in addition to the location of the newly attached IO muscle.