Torsion and clinical features in patients with acquired fourth cranial nerve palsy.

This retrospective study aimed to compare objective/subjective torsion and other clinical characteristics of patients with acquired trochlear nerve palsy. This study included 82 consecutive patients who were diagnosed with acquired fourth cranial nerve palsy between 2014 and 2021 and who were followed up for ≥ 6 months. The etiologies, ocular deviation, objective and subjective torsions were reviewed. The etiologies were classified as ischemic, traumatic, brain lesion, idiopathic, or other. The patients were classified into two groups according to the recovery state: full recovery and partial/no-recovery. We compared the torsion and clinical features based on the etiology and recovery state. The average age was 59.1 ± 11.1 years, and 58 (71.0%) of the patients were male. The most common cause was ischemic (n = 49, 59.7%) and other common causes included traumatic (n = 16, 19.5%), brain lesion (n = 8, 9.8%), idiopathic (n = 5, 6.1%) and others (n = 4, 4.9%). Of the 82 patients, 56 (68.3%) were assigned to the full recovery group, and 26 (31.7%) were assigned to the partial/no-recovery group. The average age and number of patients with ischemic causes of palsy were greater in the full recovery group (p = 0.026 and p < 0.000, respectively). The vertical deviation angle, tilted angle on the Lancaster red-green test (LRGT), proportion of patients who experienced subjective torsion on the LRGT, and head tilt were smaller in the full recovery group (p = 0.037, 0.042, 0.045, and 0.006, respectively). Ischemic trochlear nerve palsy, advanced age, a small deviation angle at the primary position, and few cases of excyclotorsion on LRGT were characteristic of the full recovery group of acquired unilateral trochlear nerve palsy patients.

Inferior oblique myectomy for postoperative limitation of elevation in abduction.

Antielevation syndrome is commonly described following anteriorization of the inferior oblique muscle. A similar phenomenon may occur following inferior oblique muscle recession, creating a distinct strabismus pattern in the setting of cranial trochlear nerve palsy. We report 3 adult patients, 69-72 years of age, who presented at the Stanford Byers Eye Institute with a similar strabismus pattern-limited elevation in abduction following previous inferior oblique muscle recession for congenital/long-standing trochlear nerve palsy. All 3 patients had a small hypertropia in primary gaze with ipsilateral inferior oblique overaction, limited elevation in abduction, and inferotemporal conjunctival scars. Two patients had a V-pattern strabismus. Following myectomy of the previously recessed inferior oblique muscle, elevation in abduction improved, and symptoms resolved in all 3 patients.

[Significance of accurately interpreting the Bielschowsky tilt test in the differential diagnosis of superior oblique muscle paralysis].

Superior oblique muscle paralysis is a common type of vertical rotatory strabismus with various subtypes. Regardless of the subtype, the Bielschowsky tilt test plays a crucial role in the diagnosis of superior oblique muscle paralysis and is often considered a significant criterion for diagnosis and differential diagnosis. However, the sensitivity and specificity of the Bielschowsky tilt test for diagnosing superior oblique muscle paralysis are not 100% due to the mechanism involved. The test is not solely based on extraocular muscle imbalance but also involves reflex pathways of the vestibular system and central nervous system. Consequently, lesions affecting corresponding areas may yield positive results in the Bielschowsky tilt test. Additionally, vestibular and central nervous system lesions can also cause strabismus, leading to a lack of one-to-one correspondence between a positive Bielschowsky tilt test and superior oblique muscle paralysis. Therefore, correctly interpreting the role of the Bielschowsky tilt test in superior oblique muscle paralysis is of paramount importance for the effective clinical management and treatment of associated conditions.

Teaching Video NeuroImage: Monocular Rotational Nystagmus Caused by Superior Oblique Myokymia.

A 61-year-old man presented with 2 days of "flickering" vision. The symptom resolved with closure of the left eye. Examination demonstrated involuntary high-frequency, low-amplitude intorting movements of the left eye, consistent with superior oblique myokymia (Video 1). Ocular ductions were full, and there were no abnormal movements of the right eye.

The Frequency and Manifestations of Ocular Causes of Abnormal Head Posture.

PURPOSE: To determine the frequency and manifestations of different ocular causes of abnormal head posture (AHP). METHOD: This prospective, consecutive case series study was performed on 149 patients with ocular AHP at Farabi hospital, Iran, from February 2020 to June 2021. All patients underwent routine ophthalmic examinations. The manifestation of AHP was determined by direct observation from three viewing angles, while the patient read the smallest line on the vision chart that they could see. In front, above, and lateral gazes, observations were performed to find head tilt, head turn, and chin abnormal position, respectively. A picture with habitual AHP was taken from all patients. The amount of head tilt was measured by calculating the angle between the line that connects the lips center to the center of the eyebrows and the vertical line using the Corel Draw X7 computer software. RESULTS: The mean age of 149 patients with ocular AHP [101 (67.8%) males and 48 (32.2%) females] was 16.2 ± 12.2 (range, 2-57) years. The most common ocular sources of AHP were found to be superior oblique palsy (SOP) in 66 (44.3%) patients, 54 (36.2%) cases with Duane's retraction syndrome (DRS), and 12 (8.1%) patients with nystagmus. Other frequent causes of ocular AHP were dissociated vertical deviation (DVD) in 5 (3.4%), A and V pattern strabismus in 3 (2.0%), and 2 cases (1.3%) in each of Brown syndrome, inferior rectus (IR) palsy, and congenital fibrosis of the extraocular muscles (CFEOM). The most common manifestations of AHP in all cases were "pure head turn" (48.3%), followed by "pure head tilt" (24.8%), "simultaneous head tilt and head turn" (20.8%), and "chin up" (6.0%). The mean head tilt among all patients with head tilt was 10.4° ± 8.9° (range, 5.0°-31.7°). CONCLUSION: The most frequent ocular sources of AHP were SOP, DRS, and nystagmus, followed by DVD, A and V pattern strabismus, IR palsy, CFEOM, and Brown syndrome. In addition, pure head turn and pure head tilt were the most common manifestations of ocular AHP but were not always seen in the same direction or combination as previously reported with these etiologies.

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

PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Comparison of head tilt test between sagging eye syndrome and acquired unilateral trochlear nerve palsy.

PURPOSE: To investigate the distinction between sagging eye syndrome (SES group) and acquired unilateral trochlear nerve palsy (Trochlear group) in the Bielschowsky head tilt test (BHTT). METHODS: Fifteen patients in the SES group (mean age 74.6 ± 5.2 years) and 14 patients in the Trochlear group (55.2 ± 15.9 years) visited the Department of Ophthalmology, Hyogo Medical University Hospital between November 2016 and October 2022 for treatment of their diplopia. Eye position was measured with the alternate prism cover test, and values for fixation of the dominant eye, or unaffected eye, were used. Cyclodeviation was measured with the synoptophore and the Glaucoma Module Premium Edition of the SPECTRALIS optical coherence tomography. In the BHTT, eye position was measured in three head postures: primary position (PP), head tilt to the side with hypertropia (Hyper), and head tilt to the side with hypotropia (Hypo). The differences in vertical deviation between PP and Hyper (Hyper - PP), PP and Hypo (PP - Hypo) and Hyper - Hypo were measured and compared. RESULTS: Vertical deviation in primary position was 7.3 ± 4.5 PD in the SES group and significantly larger (17.1 ± 8.4 PD) in the Trochlear group (p = 0.002). The vertical deviation in Hyper was significantly larger in the Trochlear group with 7.7 ± 4.7 PD and 22.1 ± 9.4 PD, respectively (p < 0.001), whereas the that in Hypo was not significantly different between the two groups with 6.5 ± 3.4 PD and 8.4 ± 6.6 PD, respectively (p = 0.725). The SES group showed no significant difference according to the 3 head postures (p = 0.311), while the Trochlear group showed a significantly different with smaller mean values in vertical deviation in Hypo (p < 0.001). The difference in the vertical deviation for the 3 head postures was the largest in Hyper - Hypo (1.7 ± 2.1 PD and 13.6 ± 7.1 PD, respectively), and the accuracy of SES was at the cutoff value of 6 PD, and it was considered not to be SES if the value was 6PD or higher. The accuracy of SES determination was 100% sensitivity and 100% specificity, and the area under the curve was 1.0. CONCLUSION: The difference in Hyper - Hypo in the BHTT may be the most useful index in differentiating SES from acquired unilateral trochlear nerve palsy; if the difference was more than 6 PD, the probability of SES was very low.

[Central trochlear nerve palsy treated with inferior oblique muscle weakening]. / Parálisis central del nervio troclear tratada con debilitamiento del músculo oblicuo inferior.

TITLE: Parálisis central del nervio troclear tratada con debilitamiento del músculo oblicuo inferior.

Surgical management of superior oblique palsy with coexisting exotropia.

PURPOSE: To analyze the surgical results of patients treated for superior oblique palsy with coexisting exotropia. METHODS: The medical records of patients with superior oblique palsy and exotropia who underwent inferior oblique weakening and simultaneous lateral rectus recession by a single surgeon from 1996 to 2022 were reviewed retrospectively. Demographics, pre- and postoperative vertical and horizontal deviation, and presence of diplopia were recorded. Surgical success was defined as horizontal deviation <10Δ and vertical deviation ≤4Δ without overcorrection or diplopia. The decision to operate for the horizontal deviation was made based on fusion in free space when the vertical deviation was offset with a prism. RESULTS: A total of 27 patients were included. Mean age was 26.1 ± 22 years (range, 26 months to 78 years). Preoperatively, mean vertical deviation was 15.2Δ ± 7.5Δ (range, 4Δ-30Δ); mean exodeviation, 17Δ ± 5.5Δ (range, 10Δ-35Δ). Of the 27 patients, 25 underwent unilateral and 2 underwent bilateral lateral rectus recession, according to the magnitude of the horizontal deviation. Mean follow-up was 3 ± 3.8 months (range, 2 weeks to 17 months). Postoperative mean vertical alignment was 3.0 ± 5.9, and horizontal alignment was 3.4Δ ± 5.2Δ (esotropia of 7Δ to exotropia of 12Δ; P < 0.0001). Nineteen patients (70%) had a successful result; 2 patients had residual exotropia of >10Δ, 2 had vertical overcorrection (range, 3Δ-4Δ), and 6 had residual vertical deviation ≥4Δ (range, 5Δ-20Δ). None had secondary esotropia >10Δ. Horizontal deviation was corrected successfully with no consecutive esotropia in 25 patients. CONCLUSIONS: In our study cohort, patients with superior oblique palsy and exotropia in whom fusion required both horizontal and vertical prism correction had a high likelihood of successful horizontal alignment after lateral rectus weakening in combination with inferior oblique surgery.

Microsurgical Resection of a Giant Trochlear Nerve Schwannoma: 2-Dimensional Operative Video.

We present the case of a 17-year-old male, who complained of a 1-year onset of pulsatile headache, dysphagia, speech changes, and emotional lability. Neuroimaging revealed a large left-sided contrast-enhancing tumor located at the infratentorial space consistent with a large trochlear nerve schwannoma. The tumor was compressing the brainstem, obstructing the outflow of the third and lateral ventricles causing hydrocephalus, and disturbing the cortico-bulbar pathways bilaterally leading to the diagnosis of pseudobulbar palsy. After the patient consented the surgical procedure, he was operated through a subtemporal transtentorial approach placed in the lateral position. A lumbar drain was used for brain relaxation during the procedure and image guidance to define the limits of surgical exposure. A microsurgical technique was used, aiming to preserve the cranial nerves and the vascular structures running through the perimesencephalic cisterns. Gross total resection was achieved and clinical course remained uneventful aside from a transient third nerve palsy. Symptoms improved and the three-month follow-up revealed an almost complete function of the oculomotor nerve (Video 1). Trochlear nerve schwannomas are the rarest variety of the cranial nerve schwannomas. Depending on tumor size, clinical and neuroimaging signs of mass effect and brainstem compression, treatment can be observation, microsurgical resection through cranial base approaches or radiosurgery.1-5.

Superior oblique palsy after facial feminization surgery.

Facial feminization surgery (FFS), or gender-affirming facial surgery, is a common procedure for patients with gender dysphoria. One goal of FFS involves extensive contouring of the frontal and nasal bones to reduce supraorbital bossing. Ophthalmic complications after FFS have been rarely reported. We report 2 cases of superior oblique palsy after FFS producing persistent vertical and torsional diplopia. One case was successfully treated with prism spectacles; the other required surgical management. Both cases likely involved surgical trauma to or disinsertion of the trochlea during orbital bony reshaping.

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

OBJECTIVES: 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). METHODS: 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. RESULTS: 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 ß = -0.617, p<0.001 in the paretic eye, and standardized ß = -0.517, p<0.001 in the non-paretic eye). CONCLUSIONS: 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.

Case report: isolated trochlear nerve palsy associated with posterior cerebral artery aneurysm.

We describe a case of isolated trochlear nerve palsy caused by an unruptured posterior cerebral artery (PCA) aneurysm in an 82-year-old male who consulted an ophthalmologist after developing diplopia. Magnetic resonance angiography showed a left PCA aneurysm in the ambient cistern, and T2WI showed an aneurysm compressing the left trochlear nerve to the cerebellar tentorium. Digital subtraction angiography revealed that the lesion was located between the left P2a segment. We attributed this isolated trochlear palsy to left PCA unruptured aneurysm pressure. Thus, we performed stent-assisted coil embolization. The aneurysm was obliterated, and trochlear nerve palsy improved completely.

Myositis of the superior oblique muscle in a patient with suspected superior oblique muscle palsy.

Orbital myositis comprises a subtype of idiopathic orbital inflammation. Symptoms and clinical signs include orbital pain, eyelid swelling, ptosis, and conjunctival chemosis, sometimes concurrent with diplopia. Orbital myositis typically occurs in an idiopathic acute form and affects one or more extraocular muscles. It mainly involves the rectus muscles; cases involving the superior oblique muscle have been rarely reported. We report the case of a 57-year-old man with sudden-onset diplopia. Initial examination was suggestive of right superior oblique muscle palsy; however, myositis of the right superior oblique muscle was confirmed on magnetic resonance imaging (MRI). The patient was started on intravenous steroid pulse treatment. The steroid was tapered for 4 months. Diplopia, exotropia, and excyclotorsion of the right eye disappeared after 3 weeks of treatment. Cranial MRI obtained 2 months after starting treatment showed a normal superior oblique muscle. There has been no recurrence with 8 months of follow-up after completing the steroid taper.

Isolated Sudden-Onset Trochlear Nerve Palsy Associated with Mild Novel Coronavirus Disease (COVID-19) Infection.

PURPOSE: To present a case of sudden isolated unilateral trochlear nerve palsy of new onset associated with a COVID-19 infection without a severe course. METHODS: A 49-year-old previously healthy man suddenly noticed seeing double while going down the stairs to go out for the first time the day after the completion of medical treatment and home isolation for COVID-19. There was no systemic disease or history of trauma. RESULTS: Magnetic resonance imaging of the brain and orbits was normal and the neurology examination revealed no pathology. The acute onset of the diplopia, the small vertical fusion amplitude, and the lack of facial asymmetry supported acquired trochlear nerve palsy. CONCLUSIONS: Trochlear nerve palsy has rarely been reported in association with the various types of viral infections. To the best of our knowledge, this is the first case of isolated unilateral trochlear nerve palsy with no additional neurological finding or any radiological finding that is possibly associated with mild SARS-CoV-2 infection.

Disinsertion-distal myectomy and tucking of inferior oblique combined with superior oblique full tendon advancement in superior oblique palsy.

PURPOSE: To assess the preliminary outcomes of inferior oblique (IO) disinsertion-distal myectomy and tucking combined with superior oblique (SO) full tendon advancement in patients with Knapp II or III superior oblique palsy. METHODS: This single-centered retrospective study included 16 eyes from 13 patients with Knapp Class II or III SO palsy. All patients underwent IO disinsertion-distal myectomy and tucking combined with SO full tendon advancement while under general anesthesia. Pre- and post-operative levels of vertical deviation in the primary position, abnormal head position, IO hyperfunction and SO hypofunction, torsion, as well as the presence of diplopia, were all measured, and the differences were statistically compared. RESULTS: Pre-operatively, 12 patients had abnormal head positions, and two had diplopia. The pre-and post-operative levels of IO hyperfunction and SO hypofunction, as well as a vertical deviation in the primary position and torsion, all differed statistically significantly (p < 0.01). CONCLUSIONS: Inferior oblique disinsertion distal myectomy and tucking combined with SO full tendon advancement surgery appears to be an effective procedure in patients with congenital and acquired Knapp Class II or III SO palsy.