Unilateral Congenital Superior Oblique Palsy Research Articles

Surgical outcomes in patients with congenital superior oblique palsy: A comparison between clinical and radiological diagnosis

PurposeThe diagnosis of superior oblique (SO) palsy can be achieved by examining the radiological and clinical characteristics. Despite their usefulness, the radiological and clinical methods are not always aligned to each other. The objective of this research is to analyze the surgical results of eyes with SO palsy, based on whether the diagnosis was made radiologically or clinically. DesignA prospective study, conducted at a single tertiary hospital. MethodsFollowing the diagnosis of SO palsy, either through clinical assessment or radiological imaging, the patients were categorized into three distinct groups according to their clinical measurements and MRI findings. Group 1 exhibited consistent clinical measurements and MRI findings indicating SO palsy, whereas Group 2 displayed clinical measurements without MRI confirmation. In contrast, Group 3 presented inconclusive measurements, but MRI scans revealed signs of atrophy. Patients underwent inferior oblique (IO) myectomy with and without contralateral inferior rectus recession and ocular deviation before and after myectomy were collected. ResultsThe study included 49 patients with congenital unilateral SO palsy (average age: 30 years). Out of 35 patients who tested positive across all three stages of the test, 15 did not show notable muscle atrophy in their MRI findings. In contrast, among those who displayed muscle atrophy in their MRI scans, 58.8 % had positive outcomes in all steps of the three-step assessment. Group 1 and 3 displayed a reduced muscle volume measuring 110.988 ± 42.49 mm³ and 91.5 ± 56.8 mm³, respectively, on the affected side. Group 2 showcased a muscle volume of 184.1 ± 44.64 mm³ on the affected side. In all three groups with SO palsy eyes who underwent IO myectomy, there was a reduction in hypertropia in the primary position, with no statistically significant differences observed among the groups (P = 0.1). All five patients with SO palsy who underwent IO myectomy with contralateral inferior rectus recession were classified in group 3, and they exhibited a significant reduction in hypertropia postoperatively. ConclusionComparable results can be attained through IO surgery in patients with SO palsy, regardless of whether they are diagnosed through clinical or radiological means.

Postoperative outcomes for unilateral congenital trochlear nerve palsy: A retrospective cohort study

Congenital trochlear nerve palsy is the most common cause of vertical strabismus. The goal of this study was to investigate surgical outcomes after superior oblique tendon plication with or without inferior oblique recession in children and adults with unilateral congenital trochlear nerve palsy. Data and outcomes were collected in patients with a diagnosis of unilateral congenital superior oblique palsy during a retrospective single-center study conducted at the University Hospital of Tours. A reproducible, standard ophthalmological and oculomotor examination was performed pre- and postoperatively at 1 year, including presence or absence of diplopia, vertical and horizontal deviations, and compensatory head posture. Surgical success, defined as an endpoint including absence of diplopia in primary position, absence of head tilt, and vertical deviation at distance fixation<5 prism diopters (PD), was analyzed. A total of fifty-seven patients (median [IQR] age of 11 years [5-42]) were analyzed. Patients experienced a significant reduction in vertical distance and near deviations (p<0.001), compensatory head tilt (p<0.001), and diplopia after surgery (p<0.001). Surgical success was higher in adults (17/24, 70.8%) than in children (15/33, 45.5%), although this did not reach statistical significance (p=0.0657). This study suggests that plication of the superior oblique muscle tendon, with or without recession of the inferior oblique muscle, can be effective in treating unilateral congenital trochlear nerve palsy. Further studies are necessary to compare surgical procedures and investigate their efficacy in adults compared to children in the short and long term.

Effect of inferior oblique myectomy on ocular torsion according to the absence of the trochlear nerve in unilateral congenital superior oblique palsy.

To evaluate the effect of inferior oblique (IO) myectomy on ocular torsion according to the absence of the trochlear nerve in unilateral congenital superior oblique palsy (UCSOP). We retrospectively reviewed the clinical data of patients who had been diagnosed with UCSOP and underwent ipsilateral IO myectomy (n = 43). Patients were classified into the present and absent groups according to the absence of the trochlear nerve and superior oblique hypoplasia on magnetic resonance imaging (MRI). For quantitative analysis of ocular torsion, disc-fovea angles (DFA) were collected in both eyes using fundus photographs taken within three months before surgery and one month after surgery. DFA of the paretic eye did not differ according to the absence of the trochlear nerve (9.4±5.6° in the present group vs. 11.0±5.4° in the absent group, p = 0.508). However, the present group had a larger DFA in the non-paretic eye than the absent group (14.1±6.7° in the present group vs. 8.0±5.0° in the absent group, p = 0.003). The change of ocular torsion after IO myectomy in the paretic eye was -5.3±3.7° in the present group and -4.8±3.5° in the absent group, respectively (p = 0.801). In the non-paretic eye, the change in DFA was -1.5±3.0° in the present group, which was larger than that in the absent group (0.7±2.6°, p = 0.047). In the multivariate analysis, the change in DFA was correlated with only the preoperative DFA (standardized β = -0.617, p<0.001 in the paretic eye, and standardized β = -0.517, p<0.001 in the non-paretic eye). In the paretic eye, there was no significant difference in the change of ocular torsion between both groups, whereas in the non-paretic eye, the present group had a larger change in DFA after IO myectomy than the absent group. However, in the multivariable analysis, the change in ocular torsion was significantly correlated with preoperative excyclotorsion but not with the presence of the trochlear nerve itself.

Clinical features of excyclotorsion in the non-paretic eye of patients with congenital unilateral superior oblique palsy

BackgroundTo investigate preoperative clinical features and postoperative results according to the correspondence between excyclotorsion and the paretic eye in patients with congenital unilateral superior oblique palsy (USOP).MethodsA retrospective review of medical charts was performed. The patients were divided into the accordance (ocular excyclotorsion in the paretic eye) and disaccordance (ocular excyclotorsion in the non-paretic eye) groups. The degree of excyclotorsion (scale, 0–4) was measured. Age, sex, hypertropia at the primary position, fixation preference, inferior oblique overaction, and degree of excyclotorsion were measured.ResultsNinety-eight patients were included in this study. There were 70 (71.4%) and 28 patients (28.6%) in the accordance and disaccordance groups. Sixteen patients (22.9%) in the accordance group and 12 patients (42.9%) in the disaccordance group were aged under 2 years (p = 0.04). A fixation preference of the paretic eye was observed in 2 (2.9%) and 8 (28.6%) patients in the accordance and disaccordance groups (p < 0.01). The postoperative degree of excyclotorsion in the accordance group (0.14 ± 0.39) was lower than that in the disaccordance group (0.28 ± 0.71) (p = 0.01). The residual postoperative excyclotorsion (> 1) were observed in the disaccordance group (14 patients, 50%) and accordance group (16 patients, 22.9%) (p = 0.01).ConclusionPreoperative disaccordance between excyclotorsion and the paretic eye was observed in patients who were under 2 years of age and preferred fixation of the paretic eye. The postoperative degree of excyclotorsion was lower in the accordance group.

Facial Asymmetry in Unilateral Congenital Superior Oblique Muscle Palsy.

This study was conducted to evaluate facial asymmetry in unilateral congenital superior oblique muscle palsy (SOP). The results showed that all facial asymmetry parameters had a higher frequency in SOP patients compared with orthotropic individuals. This study aimed to evaluate the characteristics of facial asymmetry in unilateral congenital SOP and compare with orthotropic individuals. This cross-sectional comparative case series was conducted in 58 patients with ocular torticollis caused by SOP (mean ± standard deviation age, 18 ± 12 years) and 58 orthotropic individuals (mean ± standard deviation age, 19 ± 13 years). The exact form of torticollis was determined by direct observation from yaw, roll, and pitch axes. Four photographs were taken from patients: (1) with torticollis to calculate the amount of head tilt; (2) with the head in the straight position to calculate the facial angle and relative facial size (RFS); and (3 and 4) with the head positioned downward (to compare the cheek size) and upward (to assess columella deviation and nostril asymmetry). Twenty-nine patients (50%) had a head tilt, 23 (39.66%) had combined head tilt and a face turn, and 6 (10.44%) had a pure face turn. The mean ± standard deviation of head tilt, facial angle, and RFS was 10.11 ± 6.31°, 1.11 ± 1.67°, and 1.003 ± 0.126 in SOP patients, respectively, and the mean RFS and facial angle were significantly higher in SOP patients compared with orthotropic individuals (both P < .001). Facial hemihypoplasia, unilateral cheek compression, nostril asymmetry, and columella deviation were observed in 43 (74.1%), 31 (53.4%), 39 (67.2%), and 38 patients (65.5%), respectively, which were all significantly more common compared orthotropic individuals (P < .001). Facial asymmetry was seen in 52 patients (91.2%) and 17 orthotropic subjects (29.3%), respectively (P < .001). All quantitative and qualitative facial asymmetry parameters had a higher frequency in SOP patients compared with orthotropic subjects.

Inferior oblique recession associated to partial temporal inferior rectus recession in unilateral congenital superior oblique palsy.

To evaluate the effectiveness of inferior oblique recession with contralateral partial temporal inferior rectus recession in patients with decompensated congenital unilateral superior oblique palsy (SOP) in correcting moderate vertical deviations in primary position. The medical records of patients with SOP who underwent inferior oblique recession with contralateral partial temporal inferior rectus recession were reviewed retrospectively. Vertical deviation in primary position, subjective torsion, diplopia, residual deviation, and the deviation decrease were evaluated. Four patients (three males and one female, age range 29-56 years) with congenital unilateral SOP and mean vertical deviation of 21.0 ± 5.3PD (range 14-25D) in primary position were included. Mean correction of hypertropia in primary position with this technique was 15.5 ± 5.3PD (range 10-20PD). The mean hypertropia on gaze to the contralateral side changed from 30.0 ± 10.8D before surgery to 9.3 ± 7.9D after surgery. Torsion had a mean change of 4.8° of incyclodeviation. Preoperatively, all patients had head tilt and diplopia, which was resolved in all but one patient, who will need surgery. Patients were followed an average of 18 months. No adverse events were reported in any subjects. When performing recession of inferior oblique muscles in SOP associated to a full recession of the contralateral inferior rectus, there is a risk of overcorrection in those with moderate angles. Performing a partial recession in the contralateral inferior rectus eye corrected up to 20PD in primary position in our series, reducing this risk.

Characteristics of Facial Asymmetry in Congenital Superior Oblique Palsy according to Trochlear Nerve Absence.

Methods A total of 287 consecutive patients diagnosed with congenital SOP and 82 control subjects were included. Congenital SOP patients were grouped according to the presence (present group) or absence (absent group) of the trochlear nerve using thin-section high-resolution MRI of cranial nerves. We developed a computer-aided detection (CAD) system that could automatically analyze objective indices of facial asymmetry using frontal face photographs. Results Of the 287 patients with congenital SOP, 60% of patients had ipsilateral trochlear nerve absence and superior oblique muscle (SO) hypoplasia (absent group), while the remaining 40% had a normal SO and trochlear nerve (present group). All but one objective indices related to facial asymmetry were significantly different between congenital SOP patients and controls (all P < 0.05). Among these features, the angle of nose deviation was significantly larger in the absent group compared to the present group (P < 0.001). Conclusion Objective analysis of facial asymmetry using our novel CAD system was useful for identifying distinct features of congenital SOP. Deviation of the nose was more prominent in congenital SOP patients with trochlear nerve absence.

Effect of unilateral inferior oblique weakening on fundus torsion in bilateral eyes of children with congenital superior oblique palsy.

To study the change of torsion in both eyes after unilateral inferior oblique (IO) weakening on children with congenital superior oblique palsy (SOP). This retrospective study enrolled all patients diagnosed with unilateral congenital superior oblique palsy (UCSOP) accompanied by inferior oblique overaction (IOOA). A total of 120 eyes of 60 patients were divided into group 1 (more extorted paretic eye) and group 2 (more extorted nonparetic eye). The degree of fundus torsion was evaluated before and 1mo after the IO weakening procedure. The torsion of the fundus was recorded by measuring the disk-foveal angle (DFA) using fundus photography. Group 1 included 26 cases and group 2 included 34 cases, thus the rate of extorsion was insignificantly higher in the nonparetic eye (P=0.10). The preoperative DFA in the paretic and nonparetic eyes was 13.21±5.95, 7.97±4.25 in group 1, and 4.65±3.79, 13.16±5.35 in group 2 (both P<0.001). The postoperative DFA in the paretic and nonparetic eyes was 8.57±4.87, 7.32±4.27 in group 1 (P=0.24), and 3.85±6.00 and 9.94±5.45 in group 2 (P<0.001). The amount of postoperative reduction of the DFA in the paretic and nonparetic eyes was 4.64±3.90, 0.65±0.76 in group 1 (P=0.002), and 0.80±0.81, 3.21±5.50 in group 2 (P=0.01). The difference in the amount of reduction of DFA in the more extorted eye in group 1 (paretic eye) vs group 2 (nonparetic eye) was insignificant (P=0.30). Excyclotorsion in the nonparetic eye has a similar probability in the paretic eye in UCSOP children, and weakening of the ipsilateral IO has a more obvious effect on the decrement of extorsion in the more extorted eye regardless of which eye is paretic.

Sternocleidomastoid muscle asymmetry in unilateral congenital superior oblique palsy

To determine whether there is an asymmetry in bilateral sternocleidomastoid muscle (SCM) thickness in patients with unilateral congenital superior oblique palsy (SOP) and its association with surgical results. The medical records of 186 patients with head tilt secondary to unilateral SOP, who were evaluated for the status of the SCM with neck ultrasound or magnetic resonance imaging, were reviewed. The SCM asymmetry index was calculated as a bilateral difference in the maximal muscle thickness divided by each tilted-side SCM thickness. The presence of SCM asymmetry, defined as an index of >10%, and its relationship to residual torticollis ≥5° after SOP surgery were assessed. Of 186 patients with a median age of 1.2 years, SCM asymmetry was present in 102 (54.8%) patients (6.8 ± 1.9 mm for the SOP side vs. 6.6 ± 2.1 mm for the tilted side). The SCM asymmetry did not differ according to age, amount of head tilt or hypertropia. In the patients with SCM asymmetry, more patients (87.3%) underwent physiotherapy than those without asymmetry (61.9%) (P = 0.021). In 99 patients who underwent surgery for SOP, the resolution of torticollis was not significantly different between patients with and without SCM asymmetry (87.2% vs. 76.9%, P = 0.184). Nearly half of the patients with congenital SOP had SCM thickness asymmetry that was already determined at a young age. However, the surgical results did not differ significantly with respect to SCM asymmetry when physiotherapy was combined. Thus, SOP surgery can be considered despite preoperative SCM asymmetry.

Outcome of inferior oblique disinsertion versus myectomy in the surgical treatment of unilateral congenital superior oblique palsy

To compare the outcome of inferior oblique disinsertion and myectomy in patients with unilateral congenital superior oblique palsy. In this prospective study, consecutive patients with superior oblique palsy underwent either myectomy or disinsertion of the inferior oblique muscle. Success was defined as postoperative hypertropia of ≤5Δ in primary position and no hypotropia. In cases with preoperative hypertropia of ≤5Δ, success was defined as improved hypertropia and resolution of abnormal head position (AHP). A total of 62 patients were included: 34 underwent myectomy; 28, disinsertion. Preoperative primary position hypertropia was 15.8Δ ± 7.4Δ in the myectomy group and 14.5Δ ± 7.3Δ in the disinsertion (P=0.756). AHP was present in 85.3% and 85.7% of patients, respectively (P=1). Mean follow-up was in the myectomy group 7.5±6.7months and 6.9±3.0months in the disinsertion group (P=0.637). Correction of hypertropia in primary position was more pronounced in the myectomy group (14.3Δ±7.4Δ vs 10.0Δ±5.4Δ; P=0.013). Success was achieved in 91.2% of myectomy and 60.7% of disinsertion patients (P=0.006). Persistence of AHP did not differ between groups (8.8% in the myectomy group vs 7.1% in the disinsertion group [P=1]). Comparison of patients with preoperative hypertropia of ≤15Δ revealed nonsignificant differences between groups in rate of success (100% vs 81.3% [P=0.226]) and correction of primary position hypertropia (8.8Δ±3.2Δ vs 7.6Δ±4.0Δ [P=0.336]). In our study cohort, inferior oblique myectomy had a greater effect in reduction of primary position hypertropia; however, disinsertion proved as effective as myectomy if preoperative vertical deviation was ≤15Δ. Both procedures effectively corrected AHP and demonstrated self-adjustment.

Predictive factors for corrective effect of inferior rectus recession for congenital superior oblique palsy.

To identify preoperative factors associated with the surgical corrective effect of contralateral inferior rectus recession (IRR) for vertical deviation in patients with congenital superior oblique palsy (SOP). This retrospective study included 20 treatment-naïve patients with unilateral congenital SOP (age range, 6-79years) who underwent contralateral IRR according to our basic policy to select IRR for paretic eye fixation. The corrective effect (°/mm) of IRR was defined as the difference in the vertical deviation at the primary gaze position between before and 6-18months after surgery per distance of recession. We also measured the preoperative vertical deviation at primary and secondary gaze positions, and vertical deviation with head-tilting, and calculated the difference in vertical deviation between these positions. We analyzed the correlation between the corrective effect of IRR and these study parameters. The mean corrective effect of IRR was 2.4±1.6°/mm, which had a significant correlation with preoperative differences in vertical deviation between the primary gaze position and the downward (P=0.004, r=-0.61) and contralateral gaze positions (P=0.03, r=-0.48); and the presence of preoperative stereopsis (P=0.02, r=-0.51). After excluding a statistical outlier, the correlation between the corrective effect and the difference between the primary and contralateral gaze positions was no longer significant (P=0.07), while the other two relationships remained significant. Our findings suggest that preoperative differences in vertical deviation between the primary and downward gaze positions and the presence of preoperative stereopsis are important considerations prior to performing IRR for congenital SOP, particularly with paretic eye fixation.

The influence of ocular sighting dominance on Fundus torsion in patients with unilateral congenital superior oblique palsy.

The purpose of our study was to determine whether ocular sighting dominance may influence the ocular torsion in patients with unilateral congenital superior oblique palsy (UCSOP). This retrospective study included 22 UCSOP patients with radiologic evidence of unilateral superior oblique muscle hypoplasia on orbital magnetic resonance imaging and 66 healthy individuals with normal ocular motility as controls. Ocular torsion was assessed both quantitatively and qualitatively using digital fundus photography. The disc-fovea angle (DFA) was measured quantitatively using image software on a computer screen. All fundus photographs were qualitatively graded as normal torsion, extorsion, or intorsion in all subjects, based on the location of the optic disc relative to the fovea, according to the Bixenman and von Noorden's criteria. Ocular sighting dominance was assessed by the hole-in-the-card test and the pointing test. The Mann-Whitney U test and Fisher's exact test were used to determine the association between the ocular sighting dominance and the ocular torsion. The median DFA was significantly larger in the eyes of patients with UCSOP (9.1° in the paretic eyes and 9.3° in the non-paretic eyes) than the eyes of the control group (4.3°, p<0.001 for both). Ocular dominance tests displayed that, among 22 patients, 11 were paretic eye dominant and the other 11 were non-paretic eye dominant. The sighting-dominant eyes demonstrated significantly smaller median DFA than the non-dominant eyes (8.3° and 10.7°, respectively, p=0.033), regardless of which eyes were paretic. Ten eyes of ten patients had extorsion, none had intorsion, and all the eyes of remaining 12 patients had no abnormal torsion, qualitatively. All the eyes showing extorsion in fundus photography were non-dominant eyes, regardless of whether the eyes were paretic or non-paretic. Our findings illuminate the importance of considering ocular sighting dominance for properly assessing ocular torsion in patients with UCSOP. Ocular sighting dominance may have an influence on objective ocular torsion in a way that decreases the torsion in the dominant eye, thereby hindering the abnormal ocular torsion from appearing in that eye.

The observation on efficacy of surgery for congenital unilateral superior oblique palsy

Objective To observe the efficacy of the surgery for congenital unilateral superior oblique palsy. Methods The medical records of 124 patients that underwent surgery for congennital unilateral superior oblique palsy from Oct. 2014 to Dec.2015 at Shanxi Eye Hospital were retrospectively reviewed. The chinical feature, the surgical procedures and efficacy were analyzed. Results The patients were followed up for 5-14 months after surgery. There were 110 cases recovered(88.71%), 12 cases improved(9.68%), and 2 cases invalid(1.61%). Conclusion Surgery is an effective method for congenital superior oblique palsy, the effectiveness rate is over 98%. Key words: Superior oblique palsy, congenital, unilateral; Surgery; efficacy

The effect of superior oblique tucking on the Bielschowsky head tilt test

To investigate the effect of superior oblique tucking on the Bielschowsky head tilt test. A retrospective analysis of 22 patients with congenital unilateral superior oblique palsy, who underwent tucking of the superior oblique tendon in Tianjin Eye Hospital, depending on vertical deviation in the primary position, ocular motility, objective cyclotorsion and abnormal head posture. Bielschowsky head tilt test was evaluated quantitatively by the prism cover test. Α positive Bielschowsky head tilt test was defined as one in which the vertical deviation when the head tilt to the side of the paresis was at least 5. 0(△) greater than that on tilt to the uninvolved side. The follow-up period ranged from 3 to 12 months (mean 4.6 months). Kolmogorov-Smirnov (K-S), Rank sum test and Spearman correlation analysis statistical methods were used in this study. All patients had vertical deviation and significant abnormal head posture before operation. After the procedure of superior oblique tucking,vertical deviation and symptom of unacceptable abnormal head posture were ameliorated or disappeared. OBJECTIVE torsion was 15.62°±7.36° before the surgery, 9.91°±10.09°1d after the surgery and 11.25°±9.17°at the last follow-up visit, respectively (P<0.05). We found that there were positive correlations between the objective cyclotorsion and the vertical deviation difference value between the paralyzed side and uninvolved side at 1 d after the surgery and last follow-up visit(P<0.05). The vertical deviation of the paresised eye when the head tilted to the side of paresis side and uninvolved side difference were 5.00(△)-17.00(△), average 8.68(△)±3.23(△), 1.00(△)-8.00(△),average 3.36(△)±2.01(△) and 0.00(△)-14.00(△),average 3.77(△)±3.01(△), preoperatively, 1d after the surgery and at the last follow-up visit respectively. Using Rank sum test, the pre-and postoperative difference was statistically significant (Z=-4.64, P<0.01). A positive Bielschowsky head tilt test was found in all cases preoperatively. The results of Bielschowsky tilt test was still positive in 5 cases and negative in 17 cases (77.3%). In most cases with unilateral superior oblique paresis, the results of Bielschowsky tilt test became negative after superior oblique tucking. The long-standing results is worthy of observation. (Chin J Ophthalmol, 2016, 52: 589-595).

Surgical Outcomes of Inferior Oblique Myectomy in Unilateral Congenital Superior Oblique Palsy with or without Trochlear Nerve

ObjectivesTo compare the surgical outcomes of inferior oblique (IO) myectomy in congenital superior oblique palsy (SOP) according to the presence of the trochlear nerve identified with high-resolution MRI.Data ExtractionForty-one congenital SOP patients without a trochlear nerve (absent group) and 23 patients with a trochlear nerve (present group) who underwent IO myectomy as the primary surgical treatment were retrospectively reviewed. “Motor success” was defined as postoperative ipsilateral hypertropia ≤ 4 prism diopter (PD). “Head tilt improvement” was regarded as postoperative angle of head tilt < 5 degrees (°). Success rates for motor alignment and head tilt improvement, cumulative probabilities of success, and factors influencing surgical responses were evaluated.ResultsThe cumulative probabilities of motor success at 2 years after IO myectomy were 92% in patients with a trochlear nerve and 86% in patients without a trochlear nerve (P = 0.138). The cumulative probabilities of undercorrection and recurrence of hypertropia after 2 years were 0% in the present group versus 21% in the absent group (P = 0.014). The cumulative probabilities of persistent head tilt after 2 years were 14% in the present group and 20% in the absent group (P = 0.486). A younger age at operation was associated with reduced probabilities of motor success and head tilt improvement (P = 0.009, P = 0.022 respectively). A greater preoperative angle of head tilt was associated with persistent head tilt after surgery (P = 0.038).ConclusionsCongenital SOP without a trochlear nerve had a higher risk of hypertropia undercorrection after IO myectomy compared to patients with a trochlear nerve. A younger age at operation and larger preoperative head tilt was related to poor outcomes.

Graded recession with or without anterior transposition of the inferior oblique muscle for treatment of unilateral congenital superior oblique palsy

Graded recession with or without anterior transposition of the inferior oblique muscle for treatment of unilateral congenital superior oblique palsy

Association of superior oblique muscle volumes with the presence or absence of the trochlear nerve on high-resolution MR imaging in congenital superior oblique palsy.

Congenital superior oblique palsy is known to relate to trochlear nerve absence and a variable degree of superior oblique muscle hypoplasia. The purpose of this study was to determine whether superior oblique muscle volume predicts trochlear nerve absence in congenital superior oblique palsy. A retrospective study of high-resolution MR imaging to evaluate the presence of the trochlear nerve and to measure superior oblique muscle areas and volumes with the image analysis tools of a PACS was performed in 128 consecutive patients with unilateral congenital superior oblique palsy and 34 age-matched healthy controls. Of the 128 patients with congenital superior oblique palsy, 88 had an ipsilateral trochlear nerve absence (absent group) and 40 had both trochlear nerves (present group). In patients with congenital superior oblique palsy, the paretic side superior oblique muscle volume was significantly smaller compared with the normal side only in the absent group (P < .001). The left and right side superior oblique muscle volumes were not significantly different in controls (P = .750), and the paretic and normal side superior oblique muscle volumes were not significantly different in the present group (P = .536). The cutoff value of the paretic/normal side superior oblique muscle volume ratio for diagnosing trochlear nerve absence was ≤0.75 (sensitivity 98.9%, specificity 95.0%) in patients with congenital superior oblique palsy. The ratio of paretic/normal side superior oblique muscle area and volume has an excellent predictability in diagnosing trochlear nerve absence in congenital superior oblique palsy.

Morphometry of the trochlear nerve and superior oblique muscle volume in congenital superior oblique palsy.

To infer the pathogenic mechanism of congenital superior oblique palsy (SOP) by evaluating trochlear nerve diameter (CN4D) and superior oblique muscle (SO) volume in patients with congenital SOP. The medical records of 125 patients diagnosed with unilateral congenital SOP and 34 age-matched healthy controls were reviewed retrospectively. Using thin-section high-resolution magnetic resonance imaging, we evaluated the presence of the trochlear nerve, CN4D, SO volume, and their relationship. Of the 125 patients with congenital SOP, 87 showed absence of the trochlear nerve (n = 87, 70%, absent group) and 38 showed bilateral presence of the trochlear nerve (n = 38, 30%, present group). The nonparetic side CN4D was smaller than controls in the absent group (P = 0.001), and larger than controls in the present group (P = 0.001). Trochlear nerve diameter positively correlated with SO volume in controls (P = 0.014, R(2) = 0.174) and in the nonparetic sides of congenital SOP (present group P = 0.023, R(2) = 0.135; absent group, P = 0.008, R(2) = 0.079). The paretic side SO volume did not show a linear correlation between CN4D and SO volume in the present group (P = 0.243). In congenital SOP patients without a trochlear nerve, the nonparetic side CN4D was also reduced in contrast to those with a trochlear nerve. The relatively weaker relationship of CN4D and nonparetic side SO volume in the absent group than that of the present group suggests different pathogenic mechanisms underlying these two entities of congenital SOP.

Superior oblique tucking for treatment of superior oblique palsy.

To investigate the efficacy and safety of isolated superior oblique tucking in the treatment of congenital superior oblique palsy. Twenty-one patients with unilateral congenital superior oblique palsy and lax superior oblique tendon underwent isolated superior oblique tucking and retrospective analysis of the amount of tucking procedure, preoperative and postoperative vertical deviation in the primary position and reading position, abnormal head posture, ocular motility, and corrected objective torsion. Patients were evaluated before and 6 to 12 months after surgery. The average vertical deviation in the primary position was 10.9 ± 3.3 prism diopters (PD) before surgery and 1.5 ± 2.6 PD after surgery (n = 21, P < .05). The average vertical deviation in the reading position was 15.6 ± 3.6 PD before surgery and 2.6 ± 3.1 PD after surgery (P < .05). The average corrected vertical deviation was 9.9 ± 3.2 PD in the primary position and 13.0 ± 3.4 PD in the reading position (P < .05). The amount of tucking ranged from 5 to 12 mm (mean: 8.3 ± 2.3 mm), which was not related to the corrected vertical deviation in the primary and reading positions, the preoperative vertical deviation in the reading position, or the corrected objective torsion. After surgery, all patients had head posture that was normal or less than 5°. Unremarkable superior oblique underaction and negative head tilt test were found in all patients after surgery. All patients had mild Brown syndrome after surgery, but none were symptomatic. Isolated superior oblique tucking is an efficient and safe procedure for treatment of superior oblique palsy with hyperdeviation less than 15 PD in the primary position and remarkable superior oblique underaction. The superior oblique forced duction test was the most important criterion for planning surgery.

Effects of vertical muscle surgery on differences in the orientation of Listing’s plane in patients with superior oblique palsy

Although scleral search coils are widely and accurately used for the measurement of Listing's plane in both eyes, they require specialized equipment and are invasive. In this study, we describe a convenient and less invasive method that uses a synoptometer to analyze the differences in orientation of Listing's plane (difLP), and the effects of vertical muscle surgery on the difLP tilt in patients with superior oblique palsy (SOP). Seventeen patients with unilateral congenital SOP (CSOP) and four patients with unilateral acquired SOP (ASOP) who had not undergone any strabismus surgeries were examined. Cyclodeviations of 13 vertical and horizontal gaze points within 30° were measured with a synoptometer, and the difLP tilts in the yaw and pitch planes were analyzed before and after vertical muscle surgery. The difLP tilt in the CSOP patients was significantly tilted nasally (p = 0.02) and forward on the lower side (p = 0.001), whereas that in ASOP patients tended to tilt temporally (p = 0.15). Ipsilateral inferior oblique recession (IOR) performed in seven CSOP patients tended to improve the difLP tilt in both the yaw (p = 0.07) and pitch (p = 0.09) planes, whereas contralateral inferior rectus recession (IRR) performed in three CSOP patients significantly improved the difLP tilt in the pitch plane (p = 0.015). The mean excyclodeviations in the 13 gaze points were significantly improved with both procedures (p < 0.0001 for both). The difLP tilt in the SOP patients could be analyzed with a convenient and less invasive method using a synoptometer, and dissimilar difLP tilts were confirmed in the ASOP and CSOP patients. The results of this study suggest that both IOR and IRR are reasonable treatments for improving the difLP tilt in CSOP patients. IOR should be selected for patients with a steep preoperative difLP tilt to the nasal side, whereas IRR should be selected for patients with a gentle preoperative difLP tilt.