Superior Oblique Research Articles

Magnetic Resonance Imaging in 14 Patients with Congenital Oculomotor Nerve Palsy

To elucidate the imaging findings of congenital oculomotor nerve palsy by evaluating the oculomotor nerve and extraocular muscles on magnetic resonance (MR) imaging in arelatively large series of 14patients with congenital oculomotor nerve palsy. Ophthalmologic examination of 14consecutive patients diagnosed with congenital oculomotor nerve palsy, and MR imaging of the orbit and oculomotor nerves were performed. Of the 14patients with congenital oculomotor nerve palsy, 13patients (93%) were unilateral and 12patients (86%) had incomplete palsy. On MR imaging, 5patients (36%) had hypoplasia or aplasia of the oculomotor nerve with variable degrees of extraocular muscle atrophy on the affected side. Of the 14patients, nine (64%) had normal-sized oculomotor nerves with or without muscle atrophy. The most frequently involved muscles were the inferior rectus (64%) and medial rectus (50%), followed by the superior rectus (29%) and inferior oblique muscles (14%). None of the 14patients showed an abnormal abducens nerve. Congenital oculomotor nerve palsy was mostly incomplete and hypoplasia or aplasia of the oculomotor nerve was apparent in one third of patients showing variable degrees of extraocular muscle atrophy, mostly of the medial rectus and inferior rectus muscles.

Первичная гиперфункция нижних косых мышц

In the context of the development of modern strabismology debatable issues still remain, among which the most important and long-term is the choice of tactics for the treatment of primary hyperfunction of the inferior oblique muscle. This article presents a literature review of the most significant publications of national and foreign authors concerning this topic. Criteria of differential diagnostics of primary and secondary hyperfunction of the inferior oblique muscle are presented. The main pathophysiological mechanisms of its occurrence are identified: imbalance between the superior and inferior oblique muscles, horizontal muscle dystopia, as well as prolonged occlusion and prismatic correction. The epidemiology of primary hyperfunction of the inferior oblique muscle, which develops in patients under the age of 4 years in more than half of cases, is summarized. Congenital esotropia operated on toddlers is not a clear guarantee of success in the prevention of the development of the current pathology. Primary hyperfunction occurs equally in patients with accommodative and intermittent forms of esotropia, less often in cases of acquired esotropia. The analysis of different classifications of primary hyperfunction is provided. The indications for surgical treatment and the criteria for evaluation of its efficiency are considered. The mono- or bilaterality of hyper-elevation in adduction, its symmetry, the presence of a V pattern determine the tactics and methods of treatment, the choice of which depends on the degree of hypertropy in combination with horizontal deviation. Positive and negative aspects of the most frequently performed surgical interventions on the inferior oblique muscle; technical features of marginal myotomy, myoectomy, recession and anteriorization were evaluated.

Bilateral Superior Oblique Tenectomy for Exotropia with Vertical and Lateral Incomitance

Bilateral Superior Oblique Tenectomy for Exotropia with Vertical and Lateral Incomitance

A study of superior oblique muscle changes in superior oblique palsy using magnetic resonance imaging

Objective: To observe the magnetic resonance imaging(MRI) changes of superior oblique muscle and to study the relationship between changes and clinical signs in superior oblique muscle palsy. Methods: Cross-sectional study. Data was collected from January 2014 to January 2016 in Tianjin Eye Hospital. Twenty-three(30 eyes) patients who were diagnosed with superior oblique palsy included 15 patients with congenital superior oblique palsy [9 males and 6 females aged (32±13) years (range, 12-53 years)] and 8 cases with acquired superior oblique palsy [3 males and 5 females aged (36±15) years(range, 17-62 years)]. Twenty normal volunteers [11 males and 9 females aged (35±13) years (range, 15-60 years)] were also observed. Coronal MRI was used to detect superior oblique muscle morphological changes, as well as the maximum cross-sectional area and volume changes. The relationship between the morphological changes and vertical deviation and cyclotorsion in the primary gaze was analyzed. Rank sum test, t-test and Person correlation analysis were used for statistical analysis. Results: Two morphological changes were obtained using MRI in superior oblique muscle palsy, including round (19 eyes) and oval changes (11 eyes). The maximum cross-sectional area in eyes with the palsied superior oblique muscle [round, (10.38±1.76) mm(2); oval, (11.16±2.02) mm(2)] was significantly smaller than fellow eyes [(14.16±1.88) mm(2); Z=6.208, 5.178, both P<0.001] and eyes with normal superior oblique muscle [(15.40±1.71) mm(2); Z=8.215, 6.330, both P<0.001], and the volume changes [round, (104.92±13.36) mm(3); oval, (110.43±16.11) mm(3)] were also significantly different from fellow eyes [(254.57±20.15) mm(3); Z=7.511, 5.396, both P<0.001] and eyes with normal superior oblique muscle [(258.04±16.36) mm(3); Z=10.040, 6.936, both P<0.001]. There was no significant difference in vertical deviation between round and oval superior oblique muscle palsies (P>0.05). The cyclotorsion effect of the round change in superior oblique muscle palsy was significantly less than that of the oval change (5.47°±1.05° vs. 7.36°±0.97°, t=3.083, P=0.005). The correlation of the volume changes with vertical deviation angle in the primary gaze was not significantly different (round and oval, both P<0.05), but there was a correlation between the morphological changes and cyclotorsion strabismus (r=0.631, P=0.004; r=0.801, P=0.003). Conclusions: In the patients with superior oblique palsy, MRI scans shows that the maximum cross-sectional area decreased and the volume was smaller, which indicated superior oblique muscle atrophy. Deformation of superior oblique muscle do not significantly affect the vertical deviation, but is in correlation with cyclodeviation. (Chin J Ophthalmol, 2019, 55:20-24).

Superior Oblique Palsy: Efficacy of Isolated Inferior Oblique Recession in Cases with Ipsilateral Hypertropia in Abduction

ABSTRACTPurpose: To evaluate the effects of isolated inferior oblique (IO) muscle recession in patients with superior oblique palsy (SOP) and persistent hypertropia in abduction.Methods: Retrospective review of patients with unilateral SOP who were treated with isolated IO recession by a single surgeon (MCB) between January 2008 and December 2017. We included patients with congenital and acquired fourth nerve palsies, with a hyperdeviation of less than 20 prism diopters in primary position and at least 4 prism diopters in abduction by prism and alternate cover test (PACT) during distance fixation. A minimum follow-up of 4–6 weeks was required. Age at surgery, etiology, presence of head tilt, motor alignment in primary and secondary gaze positions at distance and near using PACT, versions, ductions, and torsion were recorded from the patients’ chart.Results: Seven patients with SOP were included in this study. Four (57.14%) males, with a mean age at presentation of 41.86 years (range: 6–66 years). Mean follow-up was 13.25 months (range: 1.3–52.2 months). A decrease in mean central gaze hypertropia from 11.4 to 1.71 PD was found. A mean contralateral gaze hypertropia that decreased from 22.28 to 5.71 PD and an ipsilateral gaze hypertropia that improved from 5.86 to 1.14 PD were also noted. Torsion had a mean change of 3.4° of incyclodeviation at the final examination.Conclusions: This study confirms the efficacy of isolated maximal IO recession for the treatment of unilateral SOP that is accompanied by a modest hypertropia of the paretic eye in abduction.

Isolated superior oblique palsy as a complication of pansinusitis following root canal treatment – An unusual scenario

Isolated superior oblique (SO) palsy has been reported in cavernous sinus thrombosis, pituitary microadenoma, tuberculous meningitis, following intraoral local anesthesia, and inferior alveolar nerve block. A 14-year-old boy presented with right SO palsy. There was a history of facial cellulitis, following dental root canal treatment (RCT) 2 weeks back. Magnetic resonance imaging revealed right pansinusitis and breach of the lamina papyracea, with extension of inflammation into the orbit. Complete recovery was noted 1 week after functional endoscopic sinus surgery. The association of SO palsy with sinusitis can be explained by the anatomical proximity of the trochlear nerve to the paranasal sinus or by the extension of infection into the superior orbital fissure. Trochlear nerve is particularly vulnerable due to its location outside the annulus of Zinn. Although multiple ocular nerve palsy following sinusitis is well recognized, isolated SO palsy in pansinusitis following dental RCT has not been reported. An inflammatory etiology carries a favorable prognosis.

The Clinical Course of Superior Oblique Tuck Surgery in Patients with Unilateral Superior Oblique Palsy

The Clinical Course of Superior Oblique Tuck Surgery in Patients with Unilateral Superior Oblique Palsy

Superior oblique tuck: evaluation of surgical outcomes

ABSTRACTPurpose: To report the surgical outcomes of the superior oblique tuck procedure in the management of superior oblique palsies performed at a single centre over a 25-year period. Methods: A retrospective study of superior oblique tuck performed as a primary and secondary procedure by a single surgeon over a 25-year period between 1992 and 2016. We evaluated patient demographics, the angle of deviation pre- and post-surgery in prism dioptres (PD), amount of muscle tuck surgery performed (mm), complications (iatrogenic Brown’s Syndrome) and improvement of diplopia post-operatively. Results: 162 eyes from 162 patients were identified. Gender = 108 male patients (66.67%). Mean age at the time of surgery = 45.94 years; laterality = 85 left eyes (52.47%). 110 patients (67.90%) = congenital superior oblique palsy. Mean post-op follow-up time = 7.5 months. Mean pre-operative angle of deviation = 15.88 PD (range = 4–35 PD); mean post-operative angle of deviation = 5.09 PD (range = 0–20 PD; p < 0.0001). 157 patients (96.91%) displayed a reduction in angle of deviation post-operatively. Overall mean reduction in the angle of deviation = 10.79 PD (range = 0–34 PD). Mean amount of muscle tucking = 9.75 mm (range = 3–20 mm). 24 patients (14.82%) experienced post-operative iatrogenic Brown’s syndrome but only two of these required further corrective surgery. 138 patients (85.19%) experienced improvement of diplopia post-operatively. Overall, 54 patients (33.33%) required additional extraocular muscle surgery to reduce diplopia further. Conclusions: This large series of superior oblique tuck procedures performed over a 25-year period, displays excellent surgical outcomes with regards to reduction of the angle of deviation, diplopia and limited complications.

Establishment and clinical significance of vestibular-evoked myogenic potential detection method

Objective: To study the integrity of vestibular brain stem pathway and explore the diagnostic and clinical value of vestibular-evoked myogenic potentials (VEMPs) in central nervous system diseases through the establishment of detection method of VEMPs. Method: Seventy-two normal volunteers (included between April 2016 and July 2017) were divided into 6 groups according to different ages.All subjects were tested with short acoustic stimulation.The superior oblique, masseter and sternocleidomastoid muscles were recorded respectively, and the stable waveform was obtained: (1)the Opposite ocular potential (o- VEMP) N1 and P1; (2)the bilateral masseter potential (m-VEMP) P11; (3)the same side neck potential (c-VEMP) P13 and N23.The three detection methods were used to measure the latency period, the amplitude of the peak value, the ratio of the amplitude before and after the stimulus, and the logarithm value of the ratio. Results: The mean values of latency period of N1, P11 and P13 were 10.9-12.0 ms, 11.3-13.6 ms, 13.2-14.6 ms, among which the occurrence rates of o-vemp, m-vemp and c-vemp were respectively 97.2%, 98.5% and 95.4%.With the increase of age, the latency period of each wave was observed to be prolonged, with significant difference (P<0.05), while no significant difference in the gender and side of each wave (P> 0.05). Conclusions: VEMPs are noninvasive measurement technology, stable and reliable, and can objectively evaluate the integrity of the vestibular brainstem pathway from three segment. This technology has broad application prospects in the central nervous system diseases, especially in neurodegenerative disease.

Quantitative analysis of structure–function relationship between ocular motility and superior oblique muscle hypoplasia in unilateral superior oblique palsy

AimsTo determine the structure–function relationship between the degree of superior oblique (SO) hypoplasia and ocular motility in unilateral SO palsy.MethodsA total of 166 patients with unilateral SO palsy were divided...

Lateral Rectus-Medial Rectus Union: A New Surgical Technique for Treatment of Complete Third Nerve Palsy.

To describe a new surgical technique for the treatment of complete third nerve palsy. This study included patients with chronic complete third nerve palsy. The lateral rectus muscle was split, followed by disinsertion of the superior and inferior halves, which were passed between the sclera and superior and inferior rectus muscles, respectively. Then the medial rectus muscle was sutured as posteriorly as possible from its insertion and cut. Next, the distal stump of the medial rectus muscle was split into two halves and united with the superior and inferior halves of the lateral rectus muscle. Finally, the proximal portion of the medial rectus muscle was sutured back to its original insertion. In cases with hypotropia and a functional superior oblique muscle, superior oblique tenectomy was also performed. Success was defined as postoperative horizontal deviation of 10 prism diopters (PD) or less and vertical deviation of 5 PD or less. Ten patients with a mean age of 32.4 ± 18.4 years had surgery using this technique; 2 of them had a history of strabismus surgery. Mean exotropia was 84 ± 14.9 PD, which reduced to 6.5 ± 8.2 PD. Mean vertical deviation was 16.5 ± 10 PD, which reduced to 2.5 ± 3.5 PD. Mean follow-up was 13.2 ± 7.9 months, and the success rate was 70% and 90% for horizontal and vertical deviations, respectively. The lateral rectus-medial rectus union technique is an effective and long-lasting procedure to overcome large-angle exotropia associated with complete third nerve palsy. This method can also be employed as a reoperation procedure. [J Pediatr Ophthalmol Strabismus. 2019;56(1):10-18.].

Surgical Outcome of Single Inferior Oblique Myectomy in Small and Large Hypertropia of Unilateral Superior Oblique Palsy.

To determine the efficacy of isolated inferior oblique myectomy on hypertropia in primary position, side gazes, and tilts, and its effect on comitancy and abnormal head posture in unilateral superior oblique palsy. Thirty-nine patients with unilateral superior oblique palsy who had inferior oblique overaction underwent inferior oblique myectomy. The hypertropia was measured in primary position, side gazes, and tilts preoperatively and postoperatively. Abnormal head posture was also assessed. Success was defined as primary position hypertropia of 5 prism diopters (PD) or less. The mean distance hypertropia was 15.7 ± 7.7 PD (range: 3 to 30 PD) preoperatively and 1.5 ± 3.3 PD (range: 0 to 16 PD) postoperatively (P < .001). The mean reduction of distance hypertropia postoperatively was 14.2 ± 7.8 PD (range: 3 to 30 PD). The contralateral gaze hypertropia decreased from 21.7 ± 9.0 PD (range: 5 to 45 PD) preoperatively to 3.6 ± 5.1 PD postoperatively (range: 0 to 20 PD) and ipsilateral head tilt hypertropia decreased from 21.9 ± 8.4 PD (range: 8 to 40 PD) preoperatively to 5.0 ± 5.9 PD (range: 0 to 24 PD) postoperatively (P < .000 for both). Incomitance (contralateralipsilateral gaze hypertropia) decreased from 15.0 ± 7.4 PD (range: 3 to 35 PD) preoperatively to 2.8 ± 4.1 PD (range: 0 to 16 PD) postoperatively (P < .001). The success rate between the two groups of patients who had hypertropia of 15 PD or less and greater than 15 PD in primary position was not statistically different (94.7% vs 85%). Two patients underwent a second operation for residual hypertropia. There was no overcorrection. Thirty-two patients had abnormal head posture, which resolved postoperatively in 29 cases. Isolated inferior oblique myectomy is an effective procedure in resolving hypertropia up to 30 PD due to unilateral superior oblique palsy, with a minimal risk of overcorrection and low risk of undercorrection. It decreases incomitancy, is a self-titrating procedure, and resolves abnormal head posture efficiently. [J Pediatr Ophthalmol Strabismus. 2019;56(1):23-27.].

Clinical Features and Surgical Results in Harada-Ito Surgery Patients.

Symptomatic excyclotorsion is an important clinical problem, especially in acquired superior oblique muscle palsy. Excyclotorsion can disrupt the fusion and cause torsional diplopia. Harada-Ito surgery (HI) is a widely used method for treating excyclotorsions. This method relieves the torsional diplopia by increasing the effect of the incyclotorsion. In this study, we aimed to report the clinical features of patients with torsional diplopia due to acquired trochlear nerve palsy and the results of HI surgery in these patients.

Anterior superior oblique tuck: an alternate treatment for excyclotorsion

Excyclotorsion is typically treated with surgical procedures such as the Harada-Ito, rectus muscle transposition, and inferior oblique weakening. We describe an alternative technique, the anterior superior oblique tuck. This procedure is technically simpler than the Harada-Ito and provides similar results.

Functional anatomy of human extraocular muscles during fusional divergence.

We employed magnetic resonance imaging to quantify human extraocular muscle contractility during centered target fusion and fusional divergence repeated with each eye viewing monocularly at 20 cm through 8Δ and at 400 cm through 4Δ base in prism. Contractility, indicated by posterior partial volume (PPV) change, was analyzed in transverse rectus and in medial and lateral superior oblique (SO) muscle compartments and by cross-sectional area change in the inferior oblique (IO). At 20 cm, 3.1 ± 0.5° (SE) diverging eye abduction in 10 subjects was associated with 4.2 ± 1.5% whole lateral rectus (LR) PPV increase ( P < 0.05) and 1.7 ± 1.1% overall medial rectus (MR) PPV decrease attributable to 3.1 ± 1.8% reduction in the superior compartment ( P < 0.025), without change in its inferior compartment or in muscles of the aligned eye. At 400 cm, 2.2 ± 0.5° diverging eye abduction in nine subjects was associated with 6.1 ± 1.3% whole LR PPV increase ( P < 10-5) but no change in MR, with compartmentally similar relaxation in the LR and MR of the aligned eye. Unlike convergence, there were no IO or SO contractile changes for divergence to either target nor any change in rectus pulley positions. Results confirm and extend to proximal divergence the unique role of the superior MR compartment, yet no MR role for far divergence. Corelaxation of aligned eye LR and MR combined with failure of MR relaxation during divergence is consistent with the limited behavioral range of divergence. NEW & NOTEWORTHY Magnetic resonance imaging shows that the lateral rectus muscle must overcome continued contraction by its opponent the medial rectus when humans diverge their visual axes to achieve single, binocular vision. While the upper but not lower compartment of the medial rectus assists by relaxing for near targets, it does not do so when targets are far away. This behavior violates Sherrington's law of reciprocal action of antagonists and conventional assumptions about the ocular motor system.

T2 mapping MRI in prediction of Graves ophthalmopathy activity

Objective To explore the value of T2 mapping MRI in predicting Graves ophthalmopathy (GO) activity. Methods 74 patients with GO and 30 normal individuals underwent coronal T2 mapping MRI were analyzed prospectively from August 2010 to June 2013 in Beijing Tongren Hospital, Capital Medical University. All the GO patients met Mourits criterion, with hyperthyroidism history, and enlargement of extraocular muscles (EOMs) found by MRI. GO patients were grouped by CAS. Of which, 52 patients in CAS ≥ 3, 22 patients in CAS<3, 12 patients in CAS=0, and 10 patients in CAS=0 or 1. T2 values of EOMs (superior rectus muscle, inferior rectus muscle, medial rectus muscle, external rectus muscle and superior oblique muscle) were calculated. The differences of mean T2 values between two eyes, among EOMs, different CAS groups and controls were evaluated by paired-sample t test and one-way ANOVA, respectively. The correlation between maxT2 and CAS was conducted by Spearman rank correlation analysis in GO patients. The cut-off value of maxT2 in predicting GO activity was determined by ROC curve. Results There was no significant difference on T2 values between sides and among EOMs in control (P>0.05), while GO group showed significant difference (P<0.05) . T2 value increased by sequence of superior oblique muscle, external rectus muscle, superior rectus muscle, medial rectus muscle and inferior rectus muscle, failed to show significant difference between medial and superior rectus muscle (P=1.00). T2 value increased by sequence of normal control, CAS=0, CAS=1/2 and CAS≥ 3 group (P<0.05) . Spearman rank correlation revealed positive correlation between maxT2 and CAS (r=0.898, P<0.01). The cut-off value of maxT2 was 138.68 msec, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 63.5% (33/52), 90.9% (20/22), 94.3% (33/35), 51.3% (20/39), 71.6% (53/74), respectively. Conclusion T2 mapping MRI is valuable in predicting GO activity. Key words: Graves ophthalmopathy; Magnetic resonance imaging

Muscular-stage Dissection during Far Lateral Approach and Its Transcondylar Extension.

Background The far lateral approach includes exposure of the C1 transverse process, vertebral artery, posterior arch of the atlas, and occipital condyle. We designed a method for systematic muscular-stage dissection and present our experience with this approach. Operative Methods We used a horseshoe scalp flap that was reflected downward and medially. The lateral muscle layers were separated layer to layer to expose the suboccipital triangle. The medial muscle layers were separated in the midline and reflected in a single layer. At this stage, the midline of the C1 process and the foramen magnum were identified. The rectus capitis posterior major muscle was reflected to expose the posterior arch of the atlas. The C1 transverse process and vertebral artery were identified by reflection of the superior oblique muscle. The occipital condyle was separated accordingly. Results We used this method of muscular dissection in 10 patients (foramen magnum meningioma, n = 5; hypoglossal schwannoma, n = 2; others, n = 3). Systematic muscular-stage dissection facilitates identification of the anatomical landmarks with no vertebral artery injury. Gross total removal was obtained in all 9 patients with complex tumors. The patient with vertebral artery dissection successfully underwent proximal clipping. Conclusion Our muscular-stage dissection could contribute to safe and effective surgery for the far lateral approach.

Outcomes of esotropia surgery in Saudi Arabia: An audit from a single center

PurposeTo monitor the outcomes of surgical correction of esotropia in order to improve preoperative counselling for patients and their families. MethodsA retrospective review audit of the medical charts at King Fahad Medical City. All patients treated surgically to correct esotropia, from January 2007 to December 2013. All operated cases were included regardless of age and esotropia etiology. The study used a goal-determined metric to assess the outcomes of strabismus surgery > 6 months post-operatively, and on last follow-up. The risk factors for poor surgical outcomes were identified using a Pareto chart. ResultsA total of 99 cases with sufficient documentation to determine the surgical goal were included in the analysis. The goal was to improve eye contact (cosmetic correction) in 77.8% cases, to establish binocularity in 15.2% cases, to resolve diplopia for 4% cases, and to improve anomalous head posture for 3%. The overall outcome was excellent for 70.7% at the first follow-up and for 57.6% at the final visit. Simultaneous vertical muscle surgery and/or superior oblique muscle palsy were risk factors for poor outcome (odds ratio 3.15, 95% CI 1.11–8.99). ConclusionsExcellent outcome of esotropia surgery in this study is comparable to outcomes reported internationally using the goal determined metrics. Quality improvement processes like the Pareto chart are simple to use and helpful for determining the risk factors associated with poor surgical outcomes after esotropia correction from different etiology.

Novel surgical approach to superior oblique myokymia

Superior oblique myokymia (SOM) is a rare eye movement disorder that produces debilitating oscillopsia and diplopia. Various medical and surgical techniques have been reported to attempt to alleviate oscillopsia including superior oblique (SO) tenectomy with inferior oblique (IO) myectomy, SO nasal tendon displacement, and intracranial neurovascular decompression. These techniques have inherent risks of iatrogenic vertical strabismus or carry high risk for morbidity. We report a novel surgical approach that alleviates oscillopsia and avoids creating vertical strabismus.

Enlargement of the superior rectus and superior oblique muscles causes intorsion in Graves' eye disease

To review the prevalence of preoperative and postoperative intorsion in patients with strabismus and Graves' eye disease (GED), and to correlate the intorsion with coexisting superior rectus (SR) and superior oblique|(SO) muscle enlargement as a possible mechanism causing intorsion in these patients.