-
Journal of Current Ophthalmology 2021To review various types of extraocular muscle transposition procedures for management of strabismus in sixth cranial nerve palsy with little lateral rectus (LR) muscle... (Review)
Review
PURPOSE
To review various types of extraocular muscle transposition procedures for management of strabismus in sixth cranial nerve palsy with little lateral rectus (LR) muscle function, along with their pros and cons.
METHODS
We performed a comprehensive review of transposition procedures in sixth cranial nerve palsy, based on literature published anytime up to March 2021. A thorough search through PubMed and Cochrane databases was performed. All types of clinical studies on different transposition procedures in LR palsy, were included.
RESULTS
Eighty-six original articles in English, with full text or abstracts available, were included in the review, among which 16 are prospective studies, 48 retrospective, 3 review articles, 1 randomized clinical trial, 17 case reports, and 1 letter. Vertical rectus transposition has demonstrated promising results, especially in abduction improvement and expansion of binocular diplopia-free visual field, albeit the possible adverse effects such as anterior segment ischemia, especially in the presence of medial rectus contracture, and induced vertical deviation may become troublesome. Partial muscle transposition, single muscle transposition, and also transposition without tenotomy have all been introduced to reduce the risk of multiple muscle manipulation and ischemia. On the other hand, different adjustable transpositions are being utilized to manage concomitant or induced vertical deviations.
CONCLUSION
Transposition procedures are highly effective in the treatment of esotropia caused by complete LR palsy. Various techniques for vertical muscle transposition have been proposed, with each of them having certain advantages and disadvantages.
PubMed: 34765809
DOI: 10.4103/joco.joco_42_21 -
Oman Journal of Ophthalmology 2022To describe the clinical profile and magnetic resonance imaging findings of the brain in Duane retraction syndrome (DRS) and determine whether there is an association...
PURPOSE
To describe the clinical profile and magnetic resonance imaging findings of the brain in Duane retraction syndrome (DRS) and determine whether there is an association between clinical presentation and magnetic resonance imaging (MRI) brain characteristics.
MATERIALS AND METHODS
This was a cross-sectional study done at a tertiary care center in South India. We recruited and analyzed the clinical characteristics of 54 patients with DRS. MRI of the brain with fast imaging employing steady-state acquisition (FIESTA) was performed in 41 cases, and the cisternal segment of the sixth nerve was studied. Statistical analysis was done to determine any association between the radiological and clinical features.
RESULTS
Type 1 DRS was predominant, followed by Type 3 DRS and Type 2 DRS. 9.3% of cases were bilateral and 11.1% were familial. Orthotropia was most common, followed by esotropia and exotropia. The MRI brain showed the absence of the cisternal part of the sixth nerve on the affected side in 82% of Type 1 and 75% of Type 3 unilateral DRS. Both the abducens nerves were visualized in 19.5% of the patients with unilateral DRS. There was no statistically significant association between MRI brain findings and the clinical features.
CONCLUSIONS
MRI brain with FIESTA shows absent or hypoplastic sixth nerve in most cases of Type 1 and Type 3 DRS. However, around 20% of DRS cases may show the presence of the cisternal part of the sixth nerve. Hence, clinicians must be cautious when ruling out DRS on the basis of MRI brain findings. Although aplasia of the sixth nerve is the most frequent MRI finding, it may not be the sole etiologic factor.
PubMed: 35937749
DOI: 10.4103/ojo.ojo_133_21 -
Brain Structure & Function Sep 2021Extraocular motoneurons initiate dynamically different eye movements, including saccades, smooth pursuit and vestibulo-ocular reflexes. These motoneurons subdivide into...
Extraocular motoneurons initiate dynamically different eye movements, including saccades, smooth pursuit and vestibulo-ocular reflexes. These motoneurons subdivide into two main types based on the structure of the neuro-muscular interface: motoneurons of singly-innervated (SIF), and motoneurons of multiply-innervated muscle fibers (MIF). SIF motoneurons are thought to provoke strong and brief/fast muscle contractions, whereas MIF motoneurons initiate prolonged, slow contractions. While relevant for adequate functionality, transmitter and ion channel profiles associated with the morpho-physiological differences between these motoneuron types, have not been elucidated so far. This prompted us to investigate the expression of voltage-gated potassium, sodium and calcium ion channels (Kv1.1, Kv3.1b, Nav1.6, Cav3.1-3.3, KCC2), the transmitter profiles of their presynaptic terminals (vGlut1 and 2, GlyT2 and GAD) and transmitter receptors (GluR2/3, NMDAR1, GlyR1α) using immunohistochemical analyses of abducens and trochlear motoneurons and of abducens internuclear neurons (INTs) in macaque monkeys. The main findings were: (1) MIF and SIF motoneurons express unique voltage-gated ion channel profiles, respectively, likely accounting for differences in intrinsic membrane properties. (2) Presynaptic glutamatergic synapses utilize vGlut2, but not vGlut1. (3) Trochlear motoneurons receive GABAergic inputs, abducens neurons receive both GABAergic and glycinergic inputs. (4) Synaptic densities differ between MIF and SIF motoneurons, with MIF motoneurons receiving fewer terminals. (5) Glutamatergic receptor subtypes differ between MIF and SIF motoneurons. While NMDAR1 is intensely expressed in INTs, MIF motoneurons lack this receptor subtype entirely. The obtained cell-type-specific transmitter and conductance profiles illuminate the structural substrates responsible for differential contributions of neurons in the abducens and trochlear nuclei to eye movements.
Topics: Abducens Nerve; Animals; Eye Movements; Ion Channels; Macaca; Motor Neurons; Oculomotor Muscles; Reflex, Vestibulo-Ocular; Trochlear Nerve
PubMed: 34181058
DOI: 10.1007/s00429-021-02315-7 -
Indian Journal of Ophthalmology May 2021The aim of this study was to describe epidemiological and clinical characteristics of pediatric ocular motor cranial nerve palsy.
PURPOSE
The aim of this study was to describe epidemiological and clinical characteristics of pediatric ocular motor cranial nerve palsy.
METHODS
This was a retrospective record-based study, carried out at a tertiary eye care hospital in India, between January 2011 and January 2015 and included patients up to 16 years of age at the time of presentation, diagnosed with third, fourth, sixth nerve palsy or a combination of these with other cranial nerve palsy. Data analyzed included demographic details, etiologies, presence or absence of amblyopia, relevant investigations, and management.
RESULTS
A total of 90 cases were included in the study. Eighty patients (88.88%) presented with isolated nerve palsy. Forty-three patients (47.77%) had congenital nerve palsy. The most common nerve involved was third (n = 35, 38.88%) followed by sixth (n = 23, 25.55%) and fourth nerve (n = 22, 24.44%). Most common cause of third and fourth cranial nerve palsy was congenital (n = 18, 51.42% and n = 17, 77.30%, respectively), while it was trauma for the sixth nerve (n = 7, 30.40%). Amblyopia was most frequently associated with third cranial nerve palsy (n = 27, 77.14%). The radio-imaging yield was maximum (n = 7, 70%) for combined cranial nerve palsy. Overall 44 (48.88%) patients were managed conservatively, while 46 (51.11%) patients needed squint with or without ptosis surgery.
CONCLUSION
The most common ocular motor cranial nerve involved in the pediatric population was the third cranial nerve, and it was found to be the most amblyogenic in this age group. The neuroimaging yield was maximum for combined cranial nerve palsy. The most common conservatively managed nerve palsy in this study group was the fourth nerve palsy.
Topics: Abducens Nerve Diseases; Child; Cranial Nerve Diseases; Demography; Humans; India; Oculomotor Nerve Diseases; Retrospective Studies; Trochlear Nerve Diseases
PubMed: 33913847
DOI: 10.4103/ijo.IJO_1803_20 -
Journal of Ophthalmic Inflammation and... Mar 2021To report a case of abducens nerve palsy with associated retinal involvement due to rickettsia typhi infection.
OBJECTIVE
To report a case of abducens nerve palsy with associated retinal involvement due to rickettsia typhi infection.
MATERIAL AND METHODS
A single case report documented with multimodal imaging.
RESULTS
A 18-year-old woman with a history of high-grade fever was initially diagnosed with typhoid fever and treated with fluoroquinolone. She presented with a 5-day history of diplopia and headaches. Her best-corrected visual acuity was 20/20 in both eyes. Ocular motility examination showed left lateral gaze restriction. Lancaster test confirmed the presence of left abducens palsy. Fundus examination showed optic disc swelling in both eyes associated with superotemporal retinal hemorrhage and a small retinal infiltrate with retinal hemorrhage in the nasal periphery in the left eye. Magnetic resonance imaging (MRI) of the brain and orbits showed no abnormalities. A diagnosis of rickettsial disease was suspected and the serologic test for Richettsia Typhi was positive. The patient was treated with doxycycline (100 mg every 12 h) for 15 days with complete recovery of the left lateral rectus motility and resolution of optic disc swelling, retinal hemorrhages, and retinal infiltrate.
CONCLUSION
Rickettsial disease should be considered in the differential diagnosis of abducens nerve palsy in any patient with unexplained fever from endemic area. Fundus examination may help establish an early diagnosis and to start an appropriate rickettsial treatment.
PubMed: 33748920
DOI: 10.1186/s12348-021-00239-1 -
Singapore Medical Journal Nov 2023
PubMed: 38037779
DOI: 10.4103/singaporemedj.SMJ-2022-222 -
Romanian Journal of Ophthalmology 2022A 36-year-old female patient presented to our clinic with a two months history of diplopia and dizziness. The symptoms appeared gradually and increased in frequency and...
A 36-year-old female patient presented to our clinic with a two months history of diplopia and dizziness. The symptoms appeared gradually and increased in frequency and intensity. She had no significant medical history and she did not take any medication. A full ophthalmological consult was performed, which revealed restricted ocular motility in the left eye (LE), in left gaze. Otherwise, the examination showed no pathological findings: best corrected visual acuity (BCVA) both eyes (OU) 1 (Snellen chart), normal slit lamp examination and pupillary reflexes, normal intraocular pressure (IOP) and fundus aspect. Diplopia tests revealed a horizontal diplopia, exacerbated in left gaze. Sixth nerve palsy suspicion was raised and the patient was directed to the neurology department. Following magnetic resonance imaging, with angiographic sequence, a complex intracerebral vascular malformation that interacted with the cranial nerves and determined horizontal diplopia, was found. For a correct diagnosis, we needed a good collaboration between various medical specialties, especially ophthalmology and neurology, because patients with diplopia often present for the first time at the ophthalmologist. BCVA = best corrected visual acuity, IOP = intraocular pressure, LE = left eye, RE = right eye.
Topics: Abducens Nerve Diseases; Adult; Diplopia; Female; Humans; Intraocular Pressure; Tonometry, Ocular; Visual Acuity
PubMed: 35531446
DOI: 10.22336/rjo.2022.15 -
Journal of Neuroendovascular Therapy 2022There are few detailed reports on abducens nerve palsy due to a ruptured vertebral artery dissecting aneurysm (VADA). We investigated the clinical characteristics and...
OBJECTIVE
There are few detailed reports on abducens nerve palsy due to a ruptured vertebral artery dissecting aneurysm (VADA). We investigated the clinical characteristics and long-term course of abducens nerve palsy in ruptured VADA patients treated by endovascular surgery.
METHODS
Of the 51 cases of ruptured VADA treated by endovascular intervention from 2011 to 2019, 31 with a good/fair outcome, in which ocular motility disorder was able to be followed, were included and investigated.
RESULTS
In all, 11 patients (35.5%) had abducens nerve palsy, and the World Federation of Neurological Surgeons (WFNS) grade and Hunt & Hess (H&H) grade at the time of arrival of patients with abducens nerve palsy were significantly higher than those of patients without abducens nerve palsy. Of the 10 patients who were able to be followed, abducens nerve palsy in 3 completely recovered in 7-180 days. Abducens nerve palsy improved in five patients and remained in two patients.
CONCLUSION
More severe neurological findings on admission reflect a higher rate of abducens nerve palsy. Diplopia induced by abducens nerve palsy is one of the most important sequelae of ruptured VADA, which impairs the daily activities of the patients. Some cases of abducens nerve palsy improve over a long period. Therefore, appropriate diagnosis and follow-up should be concerned.
PubMed: 37502345
DOI: 10.5797/jnet.oa.2021-0060 -
Folia Morphologica 2023The microanatomy of the central myelin portion and transitional zone of several cranial nerves including trigeminal, facial, vestibulocochlear, glossopharyngeal, and...
BACKGROUND
The microanatomy of the central myelin portion and transitional zone of several cranial nerves including trigeminal, facial, vestibulocochlear, glossopharyngeal, and vagus nerves have been clearly demonstrated to provide information for neurovascular compression syndrome such as trigeminal neuralgia and hemifacial spasm. However, the study of oculomotor and abducens nerve is limited.
MATERIALS AND METHODS
Oculomotor and abducens nerves were harvested with a portion of brainstem and embedded in paraffin. Longitudinal and serial sections from ten of each cranial nerve were stained and a photomicrograph was taken to make the following observations and measurements: 1) patterns of central myelin portion, 2) length of central myelin portion, and 3) depth of central myelin- peripheral myelin transitional zone.
RESULTS
For oculomotor nerve, the longest central myelin bundle was always seen on the first nerve bundle and that the length of central myelin decreased gradually. For abducens nerve, morphological patterns were classified into four types based on number of nerve rootlets emerging from the brainstem and number of nerve bundles in each rootlet. Length of central myelin portion was between 0.36-6.10 mm (2.75 ± 0.83 mm) and 0.13-5.01 mm (1.66 ± 1.39 mm) for oculomotor and abducens nerves, respectively. The oculomotor nerve transitional zone depth was 0.07-058 mm (0.23 ± 0.07 mm), while for abducens nerve, depth was 0.05-0.40 mm (0.16 ± 0.07 mm). Positive weak correlations between central myelin and depth of TZ were found in oculomotor nerve (r +0.310, p < 0.05) and abducens nerves (r +0.413, p < 0.05).
CONCLUSIONS
Detailed microanatomy of the central myelin and transitional zone might be beneficial for locating the site of compression in neurovascular conflicts at oculomotor and abducens nerves.
Topics: Humans; Abducens Nerve; Myelin Sheath; Brain Stem; Trigeminal Neuralgia; Spinal Nerve Roots
PubMed: 35692113
DOI: 10.5603/FM.a2022.0057 -
Turkish Journal of Ophthalmology Aug 2022Multiple sclerosis (MS) is a chronic disorder characterized by demyelination of the central nervous system. It often presents in women aged 18-35 with neurological...
Multiple sclerosis (MS) is a chronic disorder characterized by demyelination of the central nervous system. It often presents in women aged 18-35 with neurological symptoms such as visual loss, paresthesia, focal weakness, and ataxia. Demyelination in the brainstem can result in internuclear ophthalmoplegia causing binocular horizontal diplopia. Our report details a patient with horizontal diplopia from an isolated abducens (sixth) nerve palsy as the initial symptom of MS. While rare, this demonstrates the importance of including MS in the differential diagnosis for an isolated abducens nerve palsy, especially in younger patients with no known vascular risk factors.
Topics: Abducens Nerve Diseases; Brain Stem; Diplopia; Female; Humans; Multiple Sclerosis; Ocular Motility Disorders
PubMed: 36017545
DOI: 10.4274/tjo.galenos.2022.13245