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.

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.

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.

[CASE SERIES OF EARLY NEUROIMAGING IN PATIENTS WITH VASCULAR RISK FACTORS AND ISOLATED SIX CRANIAL NERVE PALSY, DEMONSTRATING THE DILEMMA OF EARLY IMAGING].

INTRODUCTION: There are various etiologies for isolated third, fourth and sixth cranial nerve palsies. The most common etiology in adults aged 50 years and older with vascular risk factors such as diabetes, hyperlipidemia, and hyperlipidemia, is microvascular ischemia. The role of early neuroimaging in older patients with vascular risk factors presenting with acute isolated ocular motor nerve palsy is controversial. AIMS: We present six cases of patients aged 50 years and older, with vascular risk factors, who suffered from acute isolated paralysis of the sixth nerve. All cases were diagnosed with a non-microvascular ischemia etiology. RESULTS: The identified etiologies included petroclival meningioma with involvement of the cavernous sinus, metastatic hepatoma, plasmacytoma, venous thrombosis, arterial-venous malformation and aneurysm. CONCLUSIONS: Despite the high cost and presumed low yield, early neuroimaging can change the clinical management in certain cases. DISCUSSION: Previous studies have found the yield of early neuroimaging in older vasculopathic patients with acute 4th or 6th cranial nerve palsies to be 1-15%. In spite of these reports, our cases demonstrate the need for early onset imaging in these cases.

Can Binocular Alignment Distinguish Hypertropia in Sagging Eye Syndrome From Superior Oblique Palsy?

Purpose: Although the three-step test (3ST) is typically used to diagnose superior oblique palsy (SOP), sagging eye syndrome (SES) has clinical similarities. We sought to determine if alignment measurements can distinguish unilateral SOP from hypertropia in SES. Methods: We studied hypertropic subjects who underwent surface-coil magnetic resonance imaging (MRI) demonstrating either SO cross-section reduction indicative of congenital or acquired palsy (SOP group) or lateral rectus muscle sag (SES group). Alignment was measured by Hess screen and prism-cover testing. Multiple supervised machine learning methods were employed to evaluate diagnostic accuracy. Rectus pulley coordinates were determined in SES cases fulfilling the 3ST. Results: Twenty-three subjects had unilateral SOP manifested by SO atrophy. Eighteen others had normal SO size but MRI findings of SES. Maximum cross-section of the palsied SO was much smaller than contralaterally and in SES (P < 2 × 10-5). Inferior oblique cross-sections were similar in SOP and SES. In both SOP and SES, hypertropia increased in contralateral and decreased in ipsilateral gaze and was greater in ipsilateral than contralateral head tilt. In SES, nine subjects (50%) fulfilled the 3ST and had greater infraplacement of the lateral than medial rectus pulleys in the hypotropic orbit. Supervised machine learning of alignment data distinguished the diagnoses with areas under the receiver operating curves up to 0.93, representing excellent yet imperfect differential diagnosis. Conclusions: Because the 3ST is often positive in SES, clinical alignment patterns may confound SES with unilateral SOP, particularly acquired SOP. Machine learning substantially but imperfectly improves classification accuracy.

Abducens and Trochlear Nerve Palsies After COVID-19 Vaccination: Report of Two Cases.

The authors report two cases of an abducens palsy and a trochlear nerve palsy, respectively, in two patients who received a coronavirus disease 2019 (COVID-19) vaccine 2 weeks previously. Given the lack of other symptoms, normal test results, and spontaneous resolution of the diplopia, a likely association with the COVID-19 vaccine was suggested. [J Pediatr Ophthalmol Strabismus. 2022;59(5):e50-e53.].

Recurrent Painful Ophthalmoplegic Neuropathy with Unilateral Oculomotor and Trochlear Nerve Palsy in an 8-year-old Girl.

BACKGROUND: Recurrent painful ophthalmoplegic neuropathy (RPON) is a rare disorder with a unilateral headache accompanied by ipsilateral episodes of painful ocular cranial nerve neuropathy, which typically occurs in childhood. CASE REPORT: We report an 8-year-old female with four episodes of RPON involving unilateral third and fourth cranial nerves. Right eye exotropia and complete ptosis were detected on examination. Brain MRI images revealed right third nerve enhancement where it exits from the brainstem. She completely recovered after 5 weeks with the administration of prednisolone and indomethacin. DISCUSSION AND CONCLUSION: Due to the rarity of this condition in children, recurrent painful ophthalmoplegic neuropathy should be considered as a differential diagnosis of unilateral or bilateral painful ophthalmoplegia, particularly with a history of migrainous headache. Since it is a treatable entity, and repeated attacks may lead to permanent sequela, early intervention is crucial.

Pseudonystagmus in trochlear nerve palsy.

We present the case report of a patient who presented with intermittent diplopia and left hypertropia associated with an apparent left superior oblique palsy. After dissociation with cover testing, he showed conjugate rhythmic vertical eye movements present in all gazes, thought to represent rapid rhythmically alternating fixation. The vertical rhythmic movement resolved after strabismus surgery.

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

BACKGROUND: To 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). METHODS: A 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. RESULTS: Ninety-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). CONCLUSION: Preoperative 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.

Clinical outcomes and etiology of acquired sixth cranial nerve palsy.

ABSTRACT: The objective of this study was to investigate the difference in clinical features according to age and factors affecting recovery of acquired sixth cranial nerve (CN6) palsy.A total of 156 patients with acute CN6 palsy between March 2016 and August 2021 who were followed up for at least 3 months were included in this study. Etiology, rate of recovery, and factors associated with recovery were retrospectively investigated.The average age of patients with CN6 palsy was about 60years and the mean duration of recovery was about 2.5 months. Of 156 patients, 72 (46.15%) had a microvascular etiology and 25 (16.03%) patients had a brain vascular lesions. Brain neoplasm, trauma, and "others" were found in 10 (6.41%), 11 (7.05%), and 15 (9.62%) patients, respectively. Among the total of 156 patients, 28 (17.95%) failed to completely recover. Non-isolated CN6 palsy with other cranial nerve palsies were recorded in 29 (18.59%) cases. Comparison of age (<50years vs ≥50years), between recovery and non-recovery groups showed that etiology was significantly different.The recovery rate of acquired CN6 palsy was about 82% and about 27% of patients had brain lesions. Also, varying rates and duration of recovery were found according to etiology, so we should be pay attention to diagnosis of causative disease in CN6 palsy patients.

Neuro-Behçe Disease Causing Nuclear/Fascicular Forth Nerve Palsy.

ABSTRACT: Neuro-Behçe disease (NBD) has a predilection for affecting the parenchyma of the upper brainstem; however, involvement of the fourth nerve nucleus or fascicle by NBD has not been previously described. We report a case of a young man with acute right fourth nerve palsy and history of Behçet disease with an enhancing lesion in the left caudal midbrain corresponding to the left trochlear nerve nucleus/fascicle. This is the first described case of NBD producing nuclear/fascicular fourth nerve palsy. It also demonstrates an important clinicoanatomical correlate of decussation of fourth nerve fibers to the opposite side after exiting the midbrain.

Vertical Comitance of Hypertropia in Congenital and Acquired Superior Oblique Palsy.

BACKGROUND: Ivanir and Trobe have claimed that hypertropia (HT) that is greater in upgaze than downgaze, or equal to it, is characteristic of decompensated congenital superior oblique (SO) palsy and never present in ischemic, traumatic, or tumorous SO palsy. The reliability of this claim was tested in patients with SO palsy confirmed by MRI demonstration of subnormal ipsilesional SO size. METHODS: Quasi-coronal, surface coil MRI was performed in target-controlled central gaze to identify patients with a unilateral reduction in SO cross section indicative of palsy. Nine patients gave an unequivocal history or had markedly increased vertical fusional amplitudes indicative of congenital onset (mean age 38 ± 16 years, SD). Seven patients had unequivocal acquired onset (age 47 ± 14 years and symptom duration 5.4 ± 4.8 years), including 2 with demonstrated trochlear Schwannoma and 5 with onset after severe head trauma. Fifteen patients had gradually progressive onset unequivocally not congenital yet not associated with any identifiable precipitating event (age 52 ± 20 years and symptom duration 13 ± 14 years). RESULTS: Maximum SO cross section averaged 8.6 ± 3.9 mm2 in congenital palsy, not significantly different from 11.3 ± 3.5 mm2 in acquired palsy (P = 0.08) either unequivocally or progressively acquired, but significantly less than about 19 mm2 contralesionally in SO palsy (P < 10-4). Although mean central gaze HT was greater at 20.6 ± 8.0Δ in 9 cases of congenital than that in 22 acquired cases at 11.4 ± 6.8Δ (P = 0.002), HT was 8.4 ± 16.3Δ less in upgaze than downgaze in congenital SO palsy and 3.7 ± 11.2Δ less in acquired SO palsy. In congenital palsy, 33% of patients had HT greater in upgaze than downgaze while in 67% HT was greater in downgaze (by up to 42Δ). In acquired SO palsy, HT was greater in upgaze than downgaze or equal to it in 8 cases (36%, P = 0.87, X2). In acquired SO palsy, HT was greater in upgaze than downgaze in 37% and greater in downgaze than upgaze in 59% of cases. The HT was equal in upgaze and centralgaze in no congenital and 3 acquired cases of SO palsy. Trends were similar in unequivocal acquired and progressive acquired (noncongenital) SO palsy (P > 0.4). CONCLUSIONS: Hypertropia is not characteristically greater in upgaze than downgaze in congenital SO palsy proven by SO atrophy on MRI. In fact, average HT is greater in downgaze than upgaze in both acquired and congenital palsy, sometimes strikingly so in the latter. The finding of HT greater in upgaze than downgaze, or equal to it, does not reliably indicate that SO palsy is congenital, nor does maximum SO cross section.

Clinical Characteristics for Predicting Recovery of Acquired Fourth Cranial Nerve Palsy.

BACKGROUND: Fourth cranial nerve palsy is the most common disease diagnosed in patients with vertical diplopia. Although it is reported to present a good prognosis, there are currently no agreed on prognostic factors that anticipate the recovery of the palsy other than the etiology. The purpose of this study was to investigate the prognostic factors of acquired fourth cranial nerve palsy. METHODS: The medical records of consecutive patients diagnosed with acquired unilateral fourth cranial nerve palsy from 2010 to 2020 and followed up for ≥6 months were retrospectively reviewed. The cause and degree of palsy, ocular deviation (horizontal, vertical, and cyclo), and fundus torsion were reviewed. The cause of palsy was classified as ischemic, traumatic, intracranial mass, others, or idiopathic. Patients were divided into 2 groups according to palsy recovery: complete recovery (group CR) or not CR (group NCR). The clinical characteristics of the 2 groups were compared, and the risk factors for incomplete recovery were investigated. RESULTS: Thirty-five patients (25 men) were included in the study. The average age was 55.94 ± 16.11 years. CR was achieved in 23 patients (65.7%), and the time to recovery was 3.91 ± 4.03 months. The most common cause was traumatic (40.0%), followed by ischemia (37.1%), intracranial mass (11.4%), others (8.6%), and idiopathic (2.9%). The degree of palsy and fundus torsion was significantly higher in group NCR (P = 0.010 and P = 0.001). Severe oculomotor limitation, large fundus torsion, and intracranial mass cause rather than ischemic cause indicated a higher risk of incomplete or no recovery (P = 0.016, P = 0.009, and P = 0.043). CONCLUSION: Identifying whether a patient has an intracranial mass, severe oculomotor limitation, or large fundus excyclotorsion may be useful for predicting the recovery of acquired unilateral fourth cranial nerve palsy.

The spectrum and differential diagnosis of acquired ocular motor nerve palsies: a clinical study of 502 patients.

BACKGROUND: Ocular motor nerve palsies (OMNP) frequently cause patients to present in an emergency room. In the following study, we report the differential diagnosis of OMNP by use of magnetic resonance imaging (MRI) and CSF examination as a standard. METHOD: We performed a data analysis of N = 502 patients who presented with oculomotor, trochlear, and/or abducens nerve palsy in the emergency room of the Department of Neurology, University of Ulm, between January 2006 and December 2019. We report clinical and MRI scan findings in all patients; furthermore, the CSF of 398 patients has been analysed. RESULTS: Abducens nerve palsies were most common (45%), followed by palsies of the oculomotor (31%) (CNP III) and trochlear nerve (15%). Multiple OMNPs were seen in 9% of our cohort. The most common causes included inflammations (32.7%), space-occupying lesions, such as aneurysms or neoplasms (17.3%), diabetes mellitus (13.3%), and brainstem infarctions (11%). Still 23.4% of the patients could not be assigned to any specific cause after differential diagnostic procedures and were described as idiopathic. One of three patients with an inflammation and 39% of the patients with space-occupying lesions showed additional cranial nerve deficits. CONCLUSION: Inflammation and space-occupying processes were the most frequent causes of OMNP, although brainstem infarctions also play a significant role, in particular in CNP III. The presence of additional CNPs increases the probability of an inflammatory or space-occupying cause.

Skull Base Metastasis of Breast Cancer With Oculomotor and Trochlear Nerve Palsy.

Skull base metastatic tumors are rare. Breast cancer in particular can cause bone metastases after a long period of time. A 70-year-old woman presented with multiple cranial nerve palsy. Magnetic resonance imaging revealed a lesion that extended from the orbit to the base of the skull, and the patient was referred to our department. Ophthalmological evaluation showed left visual acuity impairment, left oculomotor nerve palsy, and left trochlear nerve palsy. Endoscopic biopsy performed 5 years after the completion of breast cancer treatment revealed skull base metastases. In unilateral multiple cranial nerve palsy, the possibility of skull base metastases should be considered.

Torsional incomitance after asymmetrically adjusted Harada-Ito procedures for the simultaneous correction of vertical and torsional deviations in bilateral trochlear nerve palsy.

BACKGROUND: Adjustable bilateral Harada-Ito procedures have been described, sometimes with asymmetric adjustment used to correct vertical misalignment when coexisting with torsional strabismus. We investigated the causes of significant postoperative torsional incomitance noted in some patients undergoing these procedures. METHODS: The medical records of patients who underwent bilateral Harada-Ito procedures for bilateral trochlear nerve palsy between 1980 and 2018 were reviewed retrospectively. Cases with simultaneous operation on any other oblique or vertical rectus muscle were excluded. Surgical results, especially using Lancaster red-green (Lan R-G) plots, were correlated with the procedures performed. RESULTS: A total of 17 patients were included. At their last follow-up visit (mean, 12 months after surgery), 9 were diplopia free. Of the 8 with continuing diplopia, 2 had undercorrection and 1 had Brown syndrome. In 5 patients with continuing diplopia, there was relative intorsion of the eye movement paths in upgaze and relative extorsion of these paths in downgaze, a type of torsional incomitance. Asymmetric adjustment with tightening of one superior oblique tendon, and often loosening of the contralateral superior oblique tendon, had been performed in those 5 cases. Only 1 of the successful cases had the same type of asymmetric adjustment. There was a positive association between the severity of the preoperative Lan R-G pattern and postoperative diplopia. CONCLUSIONS: Asymmetric adjustment of bilateral Harada-Ito procedures when attempting to correct the coexisting vertical misalignment can cause significant torsional incomitance with incomplete correction of extorsion in downgaze and intorsion in upgaze. This pattern may result in postoperative diplopia that is surgically challenging to correct.

Special features of superior oblique hypofunction due to tendon abnormalities.

While most cases of superior oblique (SO) hypofunction represent contractile weakness due to denervation, sometimes the lesion is exclusively in the tendon. This study sought to distinguish the pattern of incomitant strabismus caused by deficiency of SO oculorotary force caused by tendon abnormalities versus that of neurogenic palsy. Clinical and magnetic resonance imaging (MRI) findings of 7 cases of unilateral SO tendon interruption or extirpation were compared with 11 cases of age matched unilateral SO palsy having intact tendons. We compared angles of misalignment with high-resolution MRI in central gaze and deorsumversion. Muscle bellies in neurogenic palsy were markedly atrophic with maximal cross sections averaging 6.5 ± 2.7 mm2, in contrast with 13.5 ± 3.0 mm2 contralesionally (P < .0001). In contrast, SO muscle bellies ipsilateral to tendon interruption had maximum cross sections averaging 15.1 ± 3.0 mm2 occurring more posterior than on the contralesional side whose maximum averaged 12.1 ± 2.4 mm2. While cross sections of SO bellies ipsilateral to tendon interruption exhibited normal contractile increase in infraduction (P < .0005), there was nevertheless strabismus with incomitance similar to that in SO atrophy. Binocular alignment was statistically similar (P > .5) in the two groups for all diagnostic positions, including head tilt, except in deorsumversion, where cases with SO tendon abnormalities averaged 20.5 ± 6.9Δ ipsilateral hypertropia, significantly more than 8.5 ± 6.6Δ in neurogenic SO atrophy (P = .001). The average difference in hypertropia Hypertropia averaged 9D greater in deorsumversion than central gaze in tendon abnormalities, but 4.1Δ less in SO atrophy (P< .019). In contralesional version, average overelevation in adduction was 1.7 (scale of 0-4) in tendon abnormalities, and 2.6 in SO atrophy (P = .23), while average underdepression in adduction was -2.3 in cases of tendon abnormalities and -1.6 in SO atrophy (P = .82). Repair of the SO tendon in three cases was effective, while alternative procedures were performed when repair was infeasible. While both denervation and tendon interruption impair SO oculorotary function, interruption causes greater hypertropia in infraversion. Surgical tightening of interrupted SO tendons may have particularly gratifying effects. Posterior SO thickening and large hypertropia in infraversion suggest SO tendon interruption that may guide a surgical strategy of tendon repair.

Frequency of Diplopia after Intraoperative Nerve Disturbance in Trochlear Nerve Schwannoma: A Case Report and Systematic Review.

Schwannomas of the trochlear nerve are relatively rare, and most patients present with preoperative diplopia because of trochlear nerve palsy. We describe the case of a 61-year-old male patient with a trochlear nerve schwannoma and no pre- and postoperative diplopia, despite his trochlear nerve being cut during the operation. We aimed to investigate the frequency of postoperative diplopia associated with intraoperative trochlear nerve disturbance by reviewing previous case reports, wherein postoperative diplopia did not occur after the trochlear nerve was cut intraoperatively. We recorded the frequency of diplopia because of intraoperative trochlear nerve disturbance, such as the trochlear nerve being cut, in cases without pre- and postoperative diplopia. We searched the PubMed, Medline, and Google Scholar databases for works published from 1976 to 2020 and followed the preferred reporting items for systematic reviews and meta-analyses guidelines. We reviewed 36 publications and found 92 cases of trochlear nerve schwannoma. Surgical resection was performed for 43 patients, of whom 40 were kept under observation and 9 were treated with radiation therapy. Of the 43 cases, 9 without preoperative diplopia underwent gross total resection. We analyzed ten cases (including ours) without preoperative diplopia to check for postoperative diplopia. In total, four cases, including ours, did not display postoperative diplopia despite the trochlear nerve being cut. This may be attributed to the preoperatively acquired motor and sensory fusion in the patient's vision because of tumor progression. Our findings may benefit neurosurgeons who treat patients with schwannomas and help them predict patients' outcomes.