Cerebral Venous Sinus Thrombosis with Bilateral Optic Disc Swelling and Bilateral Sixth Nerve Palsies in the Absence of Headache: A Case Report.

Introduction: We report a case of cerebral venous sinus thrombosis (CVST) that presented with bilateral optic disc swelling and diplopia in the absence of headaches. Case Presentation: A 54-year-old woman with no relevant medical history presented with a 2-week history of diplopia and no loss of visual acuity in each eye. Eye movements revealed bilateral abduction deficits, and fundoscopic examination revealed bilateral optic disc swelling. Non-contrast computed tomography of the head showed no abnormalities. Magnetic resonance venography revealed the absence of flow in the superior sagittal and left transverse sinuses as a consequence of thrombosis. The patient was diagnosed with intracranial hypertension associated with abducens nerve palsies secondary to CVST and was initiated on anticoagulant therapy. CVST can lead to stroke even in younger individuals. Conclusion: CVST should be considered in differential diagnosis when bilateral papilledema and abducens nerve palsies are present, even in the absence of headache or other neurological findings.

Isolated Abducens Nerve Palsy: A Rare Manifestation of Recurrent Extramedullary Myeloma.

Multiple myeloma is a plasma cell neoplasm, which may present as a solitary plasmacytoma and, uncommonly, as an extramedullary plasmacytoma. Intracranial plasmacytomas may manifest in central nervous system involvement as cranial nerve palsies. Cranial nerve six palsy is the most common in cases of malignancy. However, isolated abducens palsy presenting as multiple myeloma recurrence is very uncommon. Here, we detail two cases in which intracranial plasmacytoma lesions were present within the region of the Dorello canal, resulting in acute isolated unilateral diplopia from disease recurrence in the absence of systemic marrow involvement.

Intradural anatomy and mobilization techniques of oculomotor, trochlear and abducens nerve after microsurgical dissection: a cadaveric study.

BACKGROUND: This study investigates the mobilization of cranial nerves in the upper clival region to improve surgical approaches. Cadaveric specimens (n = 20) were dissected to examine the oculomotor, trochlear, and abducens nerves. Dissection techniques focused on the nerves' intradural course and their relationship to surrounding structures. METHODS: Pre-dissection revealed the nerves' entry points into the clival dura and their proximity to each other. Measurements were taken to quantify these distances. Following intradural dissection, measurements were again obtained to assess the degree of nerve mobilization. RESULTS: Dissection showed that the abducens nerve takes three folds during its course: at the dural foramen, towards the posterior cavernous sinus, and lastly within the cavernous sinus. The trochlear nerve enters the dura and makes two bends before entering the cavernous sinus. The oculomotor nerve enters the cavernous sinus directly and runs parallel to the trochlear nerve. Importantly, intradural dissection increased the space between the abducens nerves (by 4.21 mm) and between the oculomotor and trochlear nerves (by 3.09 mm on average). This indicates that nerve mobilization can create wider surgical corridors for approaching lesions in the upper clivus region. CONCLUSIONS: This study provides a detailed anatomical analysis of the oculomotor, trochlear, and abducens nerves in the upper clivus. The cadaveric dissections and measurements demonstrate the feasibility of mobilizing these nerves to achieve wider surgical corridors. This information can be valuable for surgeons planning endoscopic or microscopic approaches to lesions in the upper clivus region.

Endoscopic transsphenoidal resection of parasellar abducens nerve schwannoma: A video demonstration.

Background: The abducens nerve schwannoma (ANS) in the sellar and parasellar region are extremely rare. Only around two dozen of ANS have been described in the world literature. These cases were, however, operated through the transcranial approach. We demonstrate, with the help of an edited video, that ANS located in the sellar and parasellar region can be safely and effectively operated through a transsphenoidal approach under endoscopic visualization. Case Description: Here, we present a case of a 30-year-old male who presented with a nine-month history of diplopia, weight gain, and loss of sexual functions. On neuro-opthalmological examination, a mild abducens palsy on the left side. Other cranial nerves were intact. On endocrinological testing, mild hypopituitarism on gonadal and thyroid axes. Magnetic resonance imaging (MRI) scan showed a contrast-enhanced cystic lesion in the sellar and parasellar region extending into the left temporal fossa. The patient underwent endonasal transsphenoidal endoscopic resection. A binostril standard approach was used, the left middle concha resected, and the nasoseptal flap was raised [Video 1]. The tumor was relatively soft and avascular yet invasive and could be removed with straight and curved suctions and gentle curettage. Subcapsular dissection was the key to saving the sixth nerve. Only minimal remnant posterior to the left internal carotid artery was assumed to be left behind. No cerebrospinal fluid (CSF) leakage was noted during the surgery. The skull base defect was reconstructed with the left-sided nasoseptal flap [Video 1]. Postoperatively, no new cranial nerve deficits. Diplopia is preoperative. Endocrine functions were unchanged. No CSF leak was observed. Postoperative MRI scan showed a near total resection. There was no operation-relevant complication. Diplopia resolved completely in a follow-up period of 6 months. Conclusion: The endoscopic transsphenoidal route is safe and effective for the resection of parasellar ANS. Subcapsular dissection is key to keep the sixth nerve intact.

Abducens Nerve Palsy in a Patient with COVID-19: A Case Report.

Numerous neurological manifestations associated with COVID-19 have been reported. However, abducens nerve palsy (ANP) associated with COVID-19 is very rare and mostly related to accompanying respiratory symptoms. Here we present a 29-year-old woman with unilateral ANP manifesting with diplopia and positive SARS-CoV-2 S antibodies, which were checked later. On admission, she had signs of viral pneumonia in thorax CT without any respiratory symptoms. Her cranial neuroimaging revealed no abnormality. Following treatment with favipiravir 2x1600 mg loading dose and then 2x600mg daily maintenance, dexamethasone 8 mg/day and enoxaparin 6000 IU/day, her CT findings recovered completely whereas her ANP only partially resolved. One week after the end of COVID-19 treatment, she also developed Herpes simplex keratitis which was successfully treated with valacyclovir. It should be kept in mind that isolated abducens nerve palsy may be the only finding of COVID-19 cases without any respiratory symptoms.

Unveiling the vulnerability of the human abducens nerve: insights from comparative cranial base anatomy in mammals and primates.

The topographic anatomy of the abducens nerve has been the subject of research for more than 150 years. Although its vulnerability was initially attributed to its length, this hypothesis has largely lost prominence. Instead, attention has shifted toward its intricate anatomical relations along the cranial base. Contrary to the extensive anatomical and neurosurgical literature on abducens nerve anatomy in humans, its complex anatomy in other species has received less emphasis. The main question addressed here is why the human abducens nerve is predisposed to injury. Specifically, we aim to perform a comparative analysis of the basicranial pathway of the abducens nerve in mammals and primates. Our hypothesis links its vulnerability to cranial base flexion, particularly around the sphenooccipital synchondrosis. We examined the abducens nerve pathway in various mammals, including primates, humans (N = 40; 60% males; 40% females), and human fetuses (N = 5; 60% males; 40% females). The findings are presented at both the macroscopic and histological levels. To associate our findings with basicranial flexion, we measured the cranial base angles in the species included in this study and compared them to data in the available literature. Our findings show that the primitive state of the abducens nerve pathway follows a nearly flat (unflexed) cranial base from the pontomedullary sulcus to the superior orbital fissure. Only the gulfar segment, where the nerve passes through Dorello's canal, demonstrates some degree of variation. We present evidence indicating that the derived state of the abducens pathway, which is most pronounced in humans from an early stage of development, is characterized by following the significantly more flexed basicranium. Overall, the present study elucidates the evolutionary basis for the vulnerability of the abducens nerve, especially within its gulfar and cavernous segments, which are situated at the main synchondroses between the anterior, middle, and posterior cranial fossae-a unique anatomical relation exclusive to the abducens nerve. The principal differences between the pathways of this nerve and those of other cranial nerves are discussed. The findings suggest that the highly flexed human cranial base plays a pivotal role in the intricate anatomical relations and resulting vulnerability of the abducens nerve.

A child with unilateral abducens nerve palsy and neurovascular compression in Chiari malformation type 1 resolved with posterior fossa decompression: illustrative case.

BACKGROUND: Unilateral cranial nerve (CN) VI, or abducens nerve, palsy is rare in children and has not been reported in association with Chiari malformation type 1 (CM1) in the absence of other classic CM1 symptoms. OBSERVATIONS: A 3-year-old male presented with acute incomitant esotropia consistent with a unilateral, left CN VI palsy and no additional neurological symptoms. Imaging demonstrated CM1 without hydrocephalus or papilledema, as well as an anterior inferior cerebellar artery (AICA) vessel loop in the immediate vicinity of the left abducens nerve. Given the high risk of a skull base approach for direct microvascular decompression of the abducens nerve and the absence of other classic Chiari symptoms, the patient was initially observed. However, as his palsy progressed, he underwent posterior fossa decompression with duraplasty (PFDD), with the aim of restoring global cerebrospinal fluid dynamics and decreasing possible AICA compression of the left abducens nerve. Postoperatively, his symptoms completely resolved. LESSONS: In this first reported case of CM1 presenting as a unilateral abducens palsy in a young child, possibly caused by neurovascular compression, the patient's symptoms resolved after indirect surgical decompression via PFDD.

A Male Patient Presents With Isolated Abducens Nerve Palsy: An Atypical Presentation of Ocular Myasthenia Gravis.

Myasthenia gravis is an autoimmune disease of the neuromuscular junction caused by autoantibodies directed against the acetylcholine receptors. It presents with skeletal muscle weakness, often initially presenting with ocular symptoms such as ptosis and diplopia. When myasthenia gravis is isolated to only ocular symptoms, it is referred to as ocular myasthenia gravis (OMG). Here, we present an atypical initial presentation of OMG in a 68-year-old male patient presenting with isolated abducens nerve palsy at the initial onset. With this case report, we highlight the importance of a thorough history and clinical assessment necessary for a timely diagnosis of OMG in patients who present with isolated abducens nerve palsy.

Abducens Nerve Palsy as a Rare Complication of Herpes Zoster Ophthalmicus: A Case Report.

Herpes zoster ophthalmicus (HZO) is a condition resulting from the reactivation of dormant varicella zoster virus within the sensory nerve ganglion in the ophthalmic branch of the trigeminal nerve. The tell-tale rash along one side of the nerve tract accompanied by pain, a burning sensation, and itching alerts health practitioners on the right path to diagnosis. Conversely, HZO can present with other rarer complications such as intraocular and extraocular manifestations. This case report deals with a seemingly healthy 45-year-old female who developed left abducens nerve palsy within one week of developing a vesicular rash on the same side. Curiously, those afflicted are usually of an advanced age or suffer from an immunocompromised state; this patient however suffered from no other comorbidities nor did she report having been in contact with anyone of a similar affliction. In this case, the classical treatment regime of antivirals and corticosteroids resulted in the complete resolution of the infection and the return of full ocular function. Being able to recognize and appreciate these typical and atypical signs and symptoms of HZO can aid in the further propagation of good outcomes and timely resolutions.

High-flow carotid cavernous fistula and 'white eye': A rare and easily misdiagnosed presentation - A case report and literature review.

The three classic symptoms of carotid cavernous fistula (CCF) are pulsating exophthalmos, bruit and conjunctival chemosis. Here, we present a clinical case of isolated abducens nerve palsy due to a high-flow CCF in an 84-year-old woman, without the typical congestive orbito-ocular features. It was a diagnostic challenge because, for patients older than 50 years with cardiovascular risk factors, ischaemic mononeuropathy is the most frequent aetiology. This case illustrates the least common type of CCF that can be easily misdiagnosed. Physicians should consider fistula as a possible diagnosis in a patient with isolated abducens nerve palsy even without the classic triad.

A Rare Case of Isolated Abducens Nerve Palsy With Contemporaneous Thalamic Infarct.

We report a case of isolated left abducens nerve palsy accompanying a right thalamic infarct. The patient, a 43-year-old Malay male with newly diagnosed hypertension, diabetes mellitus, and dyslipidemia, initially reported binocular diplopia on left lateral gaze persisting for five weeks. Subsequently, he experienced acute left-sided body weakness and slurred speech for over one day. Clinical examination revealed restricted left eye lateral gaze (-3) with no relative afferent pupillary defect. Additionally, decreased power (4/5) was noted in the left upper and lower limbs. Brain magnetic resonance imaging (MRI) revealed restricted diffusion in the right thalamus extending to the right posterior internal capsule, left anterior cingulate gyrus, and left caudate nucleus. The patient was initiated on antiplatelet, antihypertensive, and oral hypoglycemic agents, resulting in symptom improvement. This rare neuroophthalmological finding has not been reported previously.

Refractory Pseudomonas Osteomyelitis of the Skull Base With Gradenigo's Syndrome: Early Dysphagia and Late Abducens Nerve Palsy.

Gradenigo's syndrome (GS) is a rare entity characterized by otitis media, pain in the trigeminal nerve distribution and abducens nerve palsy. The classic triad is uncommon, making the diagnostic workup challenging. Specifically, the diagnostic approach includes medical history, a complete otorhinolaryngological examination, a pure-tone audiogram and radiological investigation such as contrast-enhanced computed tomography scan and magnetic resonance imaging of head and neck. Broad-spectrum antibiotics are the first-line treatment, such as intravenous (IV) ceftriaxone and IV metronidazole. Here, we present the case of a 71-year-old man with a previous history of otitis media and poorly controlled type 2 diabetes mellitus. He presented to our attention with facial pain, left hemilarynx paralysis, dysphagia and otorrhea. The patient was treated with broad-spectrum antibiotics without any clinical improvement. Imaging evaluations demonstrated the presence of wide and poorly defined pathological material with epicenter in the masticatory space, involving all nearby structures. The patient underwent multiple biopsies without obtaining a definitive tissue diagnosis of neoplasia. After 2 months, the patient developed delayed VI cranial nerve palsy, providing evidence of GS. Although incomplete, GS has been described in the literature; however, none of the cases exhibited a latent abducent deficit. To the best of our knowledge, this is the only case with a delayed onset of abducens nerve palsy.

Transient recurrent episodes of abducens nerve palsy and cheiro-oral syndrome in a sub-occlusive carotid bulb atherosclerotic stenosis.

We report the case of a male in his 50s with a history of smoking admitted to our hospital for three transient recurrent episodes of less than 60 min of cheiro-oral paresthesias and binocular horizontal diplopia with convergent strabismus. On admission, his neurological examination was normal. Cerebral magnetic resonance imaging showed no cerebral lesion. Computed tomography angiography showed a sub-occlusive right carotid bulb atherosclerotic stenosis, the absence of abnormality of the subclavian arteries and the origin of the vertebral arteries, and no stenosis of the basilar artery or posterior cerebral arteries. Routine blood tests were normal with glycated hemoglobin of 6.5%. The patient underwent right carotid endarterectomy. One year after carotid endarterectomy, the patient has had no other cerebrovascular events.

Further investigation of the lateral approach for the resection of Knosp grade 4 pituitary adenomas in endoscopic endonasal surgery.

OBJECTIVE: The authors performed a further in-depth study of the lateral compartment of the cavernous sinus (LCCS) by the endoscopic endonasal approach to improve the safety and efficacy of the lateral approach for the removal of Knosp grade 4 pituitary adenomas (KG4PAs). METHODS: Twenty-three cadaveric specimens were used for endoscopic endonasal dissection, and the LCCS was exposed to observe the neurovascular and fibrous structures within. A subclassification of the lateral approach based on further knowledge of the LCCS was proposed and used to resect 86 KG4PAs, and the surgical outcomes of these cases were reviewed. Type A KG4PAs represent tumor that was mainly distributed in the posterosuperior and superolateral compartments, type B KG4PAs represent tumor that was mainly distributed in the anteroinferior compartments, and type AB KG4PAs represent tumor that extended into each compartment with characteristics of types 4A and 4B. RESULTS: The authors identified multiple fibers that anchored the horizontal segment of the internal carotid artery (ICA) to the abducens nerve. The fibers, the sympathetic nerve, and the inferior lateral trunk form a partition-like structure in the LCCS named the abducens nerve-ICA complex (AIC), and the LCCS can be divided into the superolateral and inferolateral compartments by the AIC. Accordingly, the lateral approach was subclassified into the lateral superior (LS) approach and the anterior inferior (AI) approach. The LS approach was mainly used to resect type A KG4PAs, whereas the AI approach was used to resect type B KG4PAs, and a combination of the two was used to resect type AB KG4PAs. The gross-total, subtotal, and partial resection rates were 81.4%, 12.8%, and 5.8%, respectively. The numbers of cases of postoperative transient cranial nerve palsy, postoperative permanent cranial nerve palsy, ICA injury, and CSF leakage were 6 (6.9%), 2 (2.3%), 1 (1.2%), and 1 (1.2%), respectively. CONCLUSIONS: This study revealed that the LCCS is divided by the AIC into the superolateral and inferolateral compartments, avoiding the misconception that the LCCS has vertical communication. Therefore, the lateral approach was subclassified into the LS approach and the AI approach for the resection of KG4PAs, which allowed a high gross-total resection rate with acceptable safety in the surgical treatment of KG4PAs.

Bilateral Sequential Abducens Nerve Palsy After Pfizer-BioNTech COVID-19 Vaccine (BNT162b2): A Case Report and Literature Review.

This case report details the occurrence of bilateral sequential abducens nerve palsy in a previously healthy 42-year-old woman two days after receiving her first dose of the Pfizer-BioNTech COVID-19 vaccine (BNT162b2). Despite the widespread global administration of COVID-19 vaccines, instances of abducens palsy following vaccination are limited in the available literature. Considering the temporal association between vaccination and symptom onset, the absence of underlying medical conditions predisposing to such neurological manifestations, normal brain imaging results, the occurrence of other cranial palsies post-vaccination, and analogous occurrences after different vaccinations, we propose a plausible connection between the patient's abducens palsy and the COVID-19 vaccination. Our findings contribute to the growing body of evidence regarding the side effects and safety profile of COVID-19 vaccines. Importantly, the resolution of symptoms with conservative management and the uneventful administration of the second vaccine dose suggest that the observed abducens palsy may be a transient and isolated reaction.

Gradenigo Syndrome: A Case Report of a Rare Complication of Otitis Media.

Otitis media, a common inflammation of the middle ear, frequently complicates upper respiratory infections. Gradenigo's syndrome, a rare complication, manifests as suppurative otitis media, abducens nerve palsy, and severe trigeminal nerve pain. Prompt recognition is vital because of the proximity of the infection to critical neurovascular structures. We present the case of a 38-year-old female who presented with facial pain, otalgia, and diplopia following an upper respiratory infection. Examination revealed facial weakness and abducens nerve palsy. Laboratory results showed elevated inflammatory markers. Imaging confirmed middle ear involvement. Antibiotics were initiated, and myringotomy was performed, resulting in a successful outcome. This case report contributes to understanding Gradenigo's syndrome's clinical nuances, emphasizing the necessity of a structured diagnostic and therapeutic approach. Ongoing research is crucial for refining diagnostic criteria, optimizing treatment, and enhancing pathophysiological understanding. Increased medical education is imperative to ensure early detection and improved patient outcomes.

Rare Combination of Abducens Nerve Palsy and Optic Neuritis on the Same Side: Case Report and Review of 8 Patients in Literature.

The concurrent development of abducens nerve palsy and optic neuritis on the same side is rare. Here we presented an 82-year-old man who developed the combination of abducens nerve palsy and optic neuritis on the left side 2 months after the sixth inoculation of COVID-19 mRNA vaccine. In past history at 45 years old, he experienced subarachnoid hemorrhage and underwent surgery for the clipping of intracranial aneurysm. The patient had no systemic symptoms, such as general fatigue, fever, arthralgia, and skin rashes. Physical and neurological examinations were also unremarkable. Since the aneurysmal metal clip used at that time was not compatible with magnetic resonance imaging, he underwent computed tomographic (CT) scan of the head and showed no space-occupying lesion in the orbit, paranasal sinuses, and brain. As an old lesion, the anterior temporal lobe on the left side had low-density area with metallic artifact on the left side of the skull base, indicative of metal clipping. In 4 weeks of observation from the initial visit, he showed complete recovery of visual acuity and became capable of abducting the left eye in full degrees. We also reviewed 8 patients with the combination of abducens nerve palsy and optic neuritis in the literature to reveal that the combination of signs did occur in mild meningitis with rare infectious diseases and in association with preceding herpes zoster in the first branch of the trigeminal nerve. The course of the present patient suggested that the combination of signs might be vaccine-associated.

Isolated ipsilateral abducens nerve palsy and contralateral homonymous hemianopsia associated with unruptured posterior cerebral artery aneurysm: A rare neurological finding.

Cranial nerve palsies can be presenting signs of intracranial aneurysms. There is a classic pairing between an aneurysmal vessel and adjacent nerves leading to cranial neuropathy. Isolated abducens nerve palsy can be a localizing sign of an unruptured vertebrobasilar circulation aneurysm. Aneurysms involving Anterior Inferior Cerebellar Artery (AICA) and Posterior Inferior Cerebellar Artery (PICA) have been reported to be associated with abducens nerve palsy. The symptoms in unruptured aneurysms are due to the mass effect on adjacent neurovascular structures. Most of the abducens nerve palsy resolves following microsurgical clipping. Here, we present a rare case of an unruptured Posterior Cerebral Artery (PCA) aneurysm presenting with abducens nerve palsy and diplopia associated with contralateral hemianopsia which markedly improved following endovascular coil embolization.

Occurrence of the ossification of petrosphenoid ligament: a retrospective radiologic study from computed tomographic images.

BACKGROUND: Various ligaments present in the skull base are of clinical and surgical importance. One among them, is the petrosphenoid ligament (PSL). PSL may ossify either in a partial or complete form and forms the roof of Dorello's canal underneath which the abducens nerve passes. Studies argued both protective and adverse effects of the ossified PSL. Hence, the incidence of PSL ossification has become a relevant subject in clinical practice to radiologists, neurologists and neurosurgeons for understanding its potential role in abducens nerve compression. MATERIALS AND METHODS: We have undertaken this study to investigate the incidence of PSL ossification from multidetector computed tomography (MDCT) images of the patients who had been referred to the Medical Imaging Department of Mubarak Al-Kabeer Hospital in Kuwait. We retrospectively assessed a total of 200 patients' head CT scans (400 petroclival regions) between January 2021 and June 2022 in which 59% were males (n = 118) and 41% were females (n = 82) aged between 18 and 91 years. RESULTS: A total of 37 patients (26 male, 11 female) aged between 18-84 years were presented with ossification of PSL. Among these 37 patients, 28 patients were presented with unilateral ossified PSL, and 9 patients were presented with bilateral ossified PSL, amounting to the total of 46 ossified PSL from 400 CT images of the petroclival regions (11.5%). The genderwise and sidewise occurrence of the PSL ossification seen in different age groups were not statistically significant (p > 0.05). Among all the ossified cases, there was no patient presented with abducens nerve palsy. CONCLUSIONS: We believe our results provide baseline data in the region for understanding PSL ossification and its impact on the abducens nerve palsy.

Do infants with isolated congenital sixth nerve palsy require comprehensive work-up? A retrospective cohort and review of the literature.

PURPOSE: The purpose of this study is to describe a case series of infants with isolated congenital sixth nerve palsy (ICSNP) and suggest a management algorithm based on our experience and a review of the literature. METHODS: A retrospective cohort design was used. The clinical database of a single tertiary medical center was reviewed to identify all patients diagnosed with ICSNP from January 2020 to November 2022. Data were collected as follows: demographic parameters, age at initial presentation, presenting symptoms and signs, findings on ophthalmic and neurologic examinations, findings on follow-up, and outcome. RESULTS: Six patients were included. All were born at term. The average gestational weight was 3675.7 ± 262.7 g. Three mothers had gestational diabetes. Five deliveries necessitated labor induction either by oxytocin (n = 4) or by membrane stripping followed by oxytocin (n = 1). One had also gone a forceps assisted delivery. Symptoms were noticed in all newborns by their parents within the first week of life. Ophthalmological and neurological examinations were otherwise unremarkable apart of one patient with a head turn to the side of the involved eye. Four patients underwent brain imaging that were unremarkable. All abduction deficits resolved by 1 to 3 months of age. Follow up examinations were unremarkable (mean follow up 14.3 ± 5.0 months, range 4-23). CONCLUSIONS: This case series, together with previous reports, support ICSNP's benign nature. We suggest an initial basic work-up that solely includes ophthalmological and neurological examinations which will be elaborated in case of any additional pathologic findings or if ICSNP does not fully resolve by 3 months.