Recurrent Third Nerve Paresis with Migraine: A Case Report and Review of the Literature

Ophthalmoplegic migraine (OM), first described by Charcot in 1870, is a disorder characterised by recurrent episodes of migraine associated with ophthalmoplegia. It has been extensively described in children and is rarer in adults. Commonly, the third nerve is affected with pupillary involvement and, more rarely, the fourth or the sixth nerve. OM is now believed to be an inflammatory demyelinating neuropathy. However, in the largest series of OM so far, by Lal et al. it most commonly involved the sixth nerve, started with a crescendo migraine and was accompanied by no enhancement of the cranial nerves. This has led to a rethink about the role of migraine, in the pathogenesis of OM. We describe a 14-year-old boy, with a 10-year history of intermittent headache followed by drooping of right eyelid and diplopia. The current episode started with a migrainous headache, which increased in severity over 3 days, followed by right third nerve paresis with pupillary involvement. Contrast-enhanced magnetic resonance imaging (MRI) of the brain with contrast showed nodular thickening at the root entry zone of the right oculomotor nerve with bright enhancement. The child responded to oral prednisolone, which was tapered over a month. Migraine prophylaxis with propranolol was concurrently added. His repeat MRI brain showed complete disappearance of enhancement of the lesion at 1 year.

Glioblastoma multiforme with oculomotor nerve involvement: case report and literature review

Gliomas involving the cranial nerves III-XIII are rare. Even rarer are glioblastomas multiforme (GBMs) with only 10 cases previously reported. Oculomotor nerve involvement was described in only 2 patients. The mechanisms proposed so far include an origin from the nerve itself or an extension within the nerve of a midbrain tumor. We report the case of a 69-year-old man who presented with an isolated left oculomotor nerve palsy. He was found to have a left temporal GBM extended to the frontal lobe. Diagnostics and intraoperative and pathological findings clearly demonstrated a massive infiltration of the cisternal portion of the left oculomotor nerve. We suppose this could be the first case of direct oculomotor nerve invasion by exophytic spread of a supratentorial GBM or by subarachnoid seeding from a temporal tumor. Less probably, it could be the first case of an oculomotor nerve GBM with a temporal lobe invasion.

Radiologic Imaging in Third Nerve Palsy: A Case Series Investigating Etiology, Patterns, and Clinical Implications

Third nerve palsy (TNP) is a neurologic condition characterized by dysfunction of the oculomotor nerve, leading to various ocular manifestations. Optic nerve evaluation is of utmost important among all cranial nerve palsies affecting the eye. Dysfunction of the third nerve can indicate an underlying neurologic emergency, such as cavernous arteriovenous fistula or giant cell arteritis. Early recognition and prompt treatment are vital in reversing the clinical and visual impairments associated with oculomotor nerve palsy. The typical presentation of isolated TNP involves deviation of the eye in a downward and outward direction, accompanied by ptosis (drooping of the eyelid) and, potentially, pupil involvement. The decision to use vascular imaging is influenced by factors such as age and clinical risk for an aneurysm. If TNP is isolated or partially present with pupil involvement, it suggests compression of the third nerve and necessitates immediate imaging. Given the serious implications of an intracranial aneurysm, physicians often prioritize vascular imaging during the initial evaluation, if available. However, if clinical findings indicate underlying microvascular ischemia, a delay in imaging may be considered. This case series aims to explore the role of radiologic imaging in understanding the etiology, patterns, and clinical implications of TNP.

An unexpected case report of epidermoid cyst at the oculomotor nerve: mimicking a common cyst on MRI

Intracranial epidermoid cysts are benign lesions and are rarely seen in clinical practice. Owing to similarities in imaging findings to those of common cystic lesions, the preoperative diagnosis is rendered challenging. Here, we present a case report of an epidermoid cyst at the right oculomotor nerve, which was initially misdiagnosed as a common cyst. A 14-year-old female child was admitted to our department due to a previous magnetic resonance imaging scan of a cystic lesion on the right side of the saddle that was suspected to be an oculomotor nerve cyst. In our department, this patient underwent a complete surgical resection of the tumor, and the pathology results revealed an epidermoid cyst. This is the first study that reported an epidermoid cyst at the right oculomotor nerve entering the orbit, mimicking a common cyst in imaging. We hope that this study would allow clinicians to consider this type of lesion as a differential diagnosis. Moreover, we suggest that specific diffusion-weighted imaging scan should be performed to aid in the diagnosis.

An overview of third, fourth and sixth cranial nerve palsies in the setting of COVID-19: A case report and systematic review

BACKGROUND

Covid-19 has serious sequelae that may be poorly understood, underreported, and, as a result, not diagnosed promptly, such as variations in clinical manifestations of hyperinflammation among people infected with SARS-CoV-2. ophthalmoplegia can be one of these manifestations.

METHODS

We are reporting a 55-year-old male patient with unilateral diplopia considering it as a case of multisystem inflammatory syndrome in adults. We also reviewed the literature systematically for the previously reported studies/cases with third, fourth and sixth cranial nerve palsies due to or after Covid-19.

RESULTS

The literature search yielded 17 studies reporting 29 patients. 71.4% of the patients were males with a mean age of 42.23 years. Ophthalmological symptoms took 9.7 days to appear after the respiratory involvement. All patients had diplopia as part of their visual symptoms. 41.4% of the patients had unilateral sixth nerve palsy, 24% had bilateral sixth nerve involvement, 17% had fourth nerve involvement, and 27.6% had third nerve involvement.

CONCLUSION

Ophthalmoplegia is considered presenting symptom of Covid-19. Further research is needed to detect all neuro-ophthalmological manifestations of Covid-19.

Microanatomy of the central myelin portion and transitional zone of the oculomotor and abducens nerves

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.

Post-traumatic Oculomotor Nerve Palsy due to Intraneural Hemorrhage: A Case Report

Oculomotor nerve palsy following traumatic brain injury is a rare entity. A head injury can result in diffuse neuronal axonal injury with subsequent microbleed within the nerve tissue. We report an unusual case of a patient who presented with complete isolated right third nerve palsy following a road traffic accident. In this patient, magnetic resonance imaging (MRI) revealed swelling and edema of the right oculomotor nerve along its cisternal segment with contrast enhancement. The acquisition of susceptibility-weighted images on MRI helped to clinch the diagnosis of intraneural hemorrhage as a cause of post-traumatic oculomotor nerve palsy.

The trajectory of the medial longitudinal fasciculus in the human brain: A diffusion imaging-based tractography study

The aim of this study is to investigate the trajectory of medial longitudinal fasciculus (MLF) and explore its anatomical relationship with the oculomotor nerve using tractography technique. The MLF and oculomotor nerve were reconstructed at the same time with preset three region of interests (ROIs): one set at the area of rostral midbrain, one placed on the MLF area at the upper pons, and one placed at the cisternal part of the oculomotor nerve. This mapping protocol was tested in an HCP‐1065 template, 35 health subjects from Massachusetts General Hospital (MGH), 20 healthy adults and 6 brainstem cavernous malformation (BCM) patients with generalized q‐sampling imaging (GQI)‐based tractography. Finally, the 200 μm brainstem template from Center for In Vivo Microscopy, Duke University (Duke CIVM), was used to validate the trajectory of reconstructed MLF. The MLF and oculomotor nerve were reconstructed in the HCP‐1065 template, 35 MGH health subjects, 20 healthy adults and 6 BCM patients. The MLF was in conjunction with the ipsilateral mesencephalic part of the oculomotor nerve. The displacement of MLF was identified in all BCM patients. Decreased QA, RDI and FA were found in the MLF of lesion side, indicating axonal loss and/or edema of displaced MLF. The reconstructed MLF in Duke CIVM brainstem 200 μm template corresponded well with histological anatomy. The MLF and oculomotor nerve were visualized accurately with our protocol using GQI‐based fiber tracking. This GQI‐based tractography is an important tool in the reconstruction and evaluation of MLF.

Blood Supply of Cranial Nerves Passing Through the Cavernous Sinus: An Anatomical Study and Its Implications for Microsurgical and Endoscopic Cavernous Sinus Surgery

Background

Despite improvements in surgical techniques, cranial nerve (CN) deficits remain the most frequent cause of disability following cavernous sinus (CS) surgery. The most common tumor affecting the CS is meningioma. They originate from lateral wall and have their blood supply from meningohypophyseal trunk (MHT) and inferolateral trunk (ILT). Pituitary adenomas commonly invade the CS through its medial wall and receive blood supply form medial branches of the internal carotid artery (ICA) (superior and inferior hypophyseal arteries). Some tumors may grow within the CS (e.g. trigeminal schwannomas, hemangiomas). These tumors are fed by all the intracavernous ICA branches. Tumors involving the CS may also displace the neurovascular structures, therefore, a better understanding of intracavernous neurovascular anatomy may reduce the postoperative morbidity associated with approaching CS tumors. In this anatomical study, the anatomic variations and their clinical implications of the intracavernous CNs' blood supply were evaluated through transcranial and endonasal routes.

Methods

Twenty sides of ten adult cadaveric formalin-fixed, latex-injected specimens were dissected in stepwise fashion under microscopic and endoscopic magnification. The origin and course of the intracavernous ICA branches supplying the intracavernous CNs are studied.

Results

The proximal segment of the oculomotor nerve receives blood supply from the ILT in 85%, and the tentorial artery of the MHT in 15% of specimens. The distal segment is exclusively supplied by the ILT. The proximal trochlear nerve receives blood supply from the ILT (75%) and the tentorial artery (25%); the distal segment is exclusively supplied by the superior orbital branch. The proximal third of the abducens nerve receives its vascularity exclusively from the dorsal meningeal artery, and its middle and distal thirds from the ILT. The ophthalmic and proximal maxillary segments of the trigeminal nerve also receive blood supply from the ILT. The distal maxillary segment is supplied by the artery of the foramen rotundum. All ILT branches terminate on the inferomedial aspects of the intra-cavernous CNs. Extensive anastomoses are found between ILT branches and the branches arising from external carotid artery.

Conclusion

Understanding the anatomy of the intracavernous ICA's branches is important to improving surgical outcomes with tumors involving the CS.

Recurrent painful ophthalmoplegic neuropathy revealing oculomotor nerve schwannoma

Painful ophthalmoplegia is a common presenting symptom in neuro-ophthalmology emergencies. We report an unusual case of a recurrent painful ophthalmoplegia due to a third nerve schwannoma mimicking « ophthalmoplegic migraine ». A 18 year-old girl had presented 4 episodes of left eye painful ophthalmoplegia respectively in 8, 13, 16 and 17 years old. One year after the last episode, neurological examination was normal. Brain MRI focused on the oculomotor nerve showed an enhancing nodular lesion suggesting a third nerve schwannoma. Thus, recurrent painful ophthalmoplegia revealing oculomotor nerve schwannoma, as described in our case, is exceptional. To our knowledge, only thirteen cases have been reported in the literature. Third nerve schwannoma is a rare cranial nerve tumor, typically revealed by progressive palsy of the oculomotor nerve. Recurrent painful ophthalmoplegia with persistent headache and enhancement in brain imaging should suggest tumoral lesions.

Acute-onset binocular diplopia in neurological unit: Aetiological factors and diagnostic assessment

OBJECTIVES

To investigate the aetiology of acute-onset binocular diplopia (AOBD) in neurological units and identify the key diagnostic procedures in this setting.

MATERIALS AND METHODS

Clinico-demographic data from patients hospitalized for AOBD from 2008 to 2019 were retrospectively reviewed. AOBD due to an underlying neurological disorder known to cause diplopia was addressed as secondary diplopia. Ophthalmoparesis plus was defined when subtle neurological signs/symptoms other than ophthalmoparesis were detected during neurological examination.

RESULTS

A total of 171 patients (mean age 57.6 years) were included in the study. A total of 89 subjects (52%) had an oculomotor disturbance consistent with sixth nerve palsy, and 42 (24.6%) showed multiple oculomotor nerve involvement. The most common cause of AOBD was presumed to be microvascular in 56 patients (32.7%), while a secondary aetiology was identified in 102 (59.6%). Ophthalmoparesis plus and multiple oculomotor nerve involvement significantly predicted a secondary aetiology in multivariable logistic regression analysis. Brain CT was never diagnostic in isolated ophthalmoparesis. A combination of neuroimaging examinations established AOBD diagnosis in 54.9% of subjects, whereas rachicentesis and neurophysiological examinations were found to be performant in the remaining cases.

CONCLUSIONS

AOBD may herald insidious neurological disease, and an extensive diagnostic workup is often needed to establish a diagnosis. Neurological examination was pivotal in identifying patients at higher risk of secondary aetiology. Even in cases of apparently benign presentation, a serious underlying disease cannot be excluded. Brain MRI was found to perform well in all clinical scenarios, and it should be always considered when managing AOBD.

Pupil-sparing cranial nerve III palsy after intranasal cocaine treatment for cluster headache

This case report discusses a cranial nerve III palsy in a 47-year-old, type II diabetic man that originally presented with a cluster headache that was treated with 100% oxygen by nasal cannula, 975 mg Tylenol, and 100 mg of Imitrex without any symptom relief. He then received a sphenopalatine fossa block using 1 ampule of 4% cocaine. Three days after medicinal, intranasal cocaine for treatment of a cluster headache, the patient presented with a cranial nerve III palsy with spontaneous resolution in 4 months without any intervention. Previously, intranasal cocaine had been standard treatment for cluster headaches; however, recently lidocaine has come into favor for the sphenopalatine block. Intranasal cocaine has been associated with cerebrovascular accidents, even in young adults. The time from cocaine use to cerebrovascular accident can range from hours to years. This known side effect of intranasal cocaine in young, otherwise healthy individuals should be considered when this medication is being used to treat headache, especially in higher risk patients. Therefore, when considering a sphenopalatine nerve block for treatment of headaches, both cluster and migraine, lidocaine should be the preferential treatment over intra-nasal cocaine.

Anatomy of the Orbit

The orbit is a paired, transversely oval, and cone-shaped osseous cavity bounded and formed by the anterior and middle cranial base as well as the viscerocranium. Its main contents are the anterior part of the visual system, globe and optic nerve, and the associated neural, vascular, muscular, glandular, and ligamentous structures required for oculomotion, lacrimation, accommodation, and sensation. A complex stream of afferent and efferent information passes through the orbit, which necessitates a direct communication with the anterior and middle cranial fossae, the pterygopalatine and infratemporal fossae, as well as the aerated adjacent frontal, sphenoidal, and maxillary sinuses and the nasal cavity. This article provides a detailed illustration and description of the microsurgical anatomy of the orbit, with a focus on the intrinsically complex spatial relationships around the annular tendon and the superior orbital fissure, the transition from cavernous sinus to the orbital apex. Sparse reference will be made to surgical approaches, their indications or limitations, since they are addressed elsewhere in this special issue. Instead, an attempt has been made to highlight anatomical structures and elucidate concepts most relevant to safe and effective transcranial, transfacial, transorbital, or transnasal surgery of orbital, periorbital, and skull base pathologies.

Intramuscular Nerves of the Inferior Rectus Muscle: Distribution and Characteristics

PURPOSE

Knowledge of the distribution of intramuscular nerves of the extraocular muscles is crucial for understanding their function. The purpose of this study was to elucidate the intramuscular distribution of the oculomotor nerve within the inferior rectus muscle (IRM) using Sihler's staining.

METHOD

Ninety-three IRM from 50 formalin-embalmed cadavers were investigated. The IRM including its branches of the oculomotor nerve was finely dissected from its origin to the point where it inserted into the sclera. The intramuscular nerve course was investigated after performing Sihler's whole-mount nerve staining technique that stains the nerves while rendering other soft tissues either translucent or transparent.

RESULTS

The oculomotor nerve enters the IRM around the distal one-fourth of the muscle and then divides into multiple smaller branches. The intramuscular nerve course finishes around the distal three-fifth of the IRM in gross observations. The types of branching patterns of the IRM could be divided into two subcategories based on whether or not topographic segregation was present: (1) no significant compartmental segregation (55.9% of cases) and (2) a several-zone pattern with possible segregation (44.1% of cases). Possible compartmentalization was less clear for the IRM, which contained overlapping mixed branches between different trunks.

CONCLUSION

Sihler's staining is a useful technique for visualizing the gross nerve distribution of the IRM. The new information about the nerve distribution and morphological features provided by this study will improve the understanding of the biomechanics of the IRM, and could be useful for strabismus surgery.

Anatomical study on branching pattern and variations of orbital segment of the oculomotor nerve

BACKGROUND

This study aims to revisit the anatomy of orbital segment of the third cranial nerve (CN III). The study also involved morphometric measurements of CN III muscular branches. Detailed description of observed anatomical variations and their incidence was also included. The study supplements earlier findings with detailed observations of the neuromuscular relations.

MATERIALS AND METHODS

The study was conducted on 52 orbits taken from 26 cadaveric heads (10 males and 16 females; Central European population).

RESULTS

Anatomical variations of the orbital segment of the CN III observed on the examined material involved both the superior and inferior branch of this nerve. The muscular branch innervating the levator palpebrae superioris muscle occasionally pierces the superior rectus muscle. The nerve to the inferior oblique muscle may pierce and innervate the inferior rectus muscle. In rare instances, duplication of the parasympathetic root of the ciliary ganglion may also occur. Among the muscular branches, the smallest diameter reached the branch to the levator palpebrae superioris muscle. Among the three muscular branches derived from the inferior branch of the CN III, the nerve to the inferior oblique was the longest one. Its length varied from 28.9 mm to 37.4 mm. The shortest was the muscular branch to the inferior rectus muscle. Its length varied from 0 mm (when muscular sub-branches arose directly from the nerve to the inferior oblique muscle) to 7.58 mm.

CONCLUSIONS

This study presented the characteristic of orbital segment of the CN III, including anatomical variations and morphometric measurements relevant to intraorbital procedures.

Oculomotor Nerve Palsy in the Emergency Department: A Complication of Epidural Injection

BACKGROUND

Epidural injections are routinely used for management of radicular pain and are prevalent nonsurgical interventions for chronic low back pain. Pneumocephalus is a rare complication that may occur as a result of inadvertent dural puncture with an epidural needle. Pneumocephalus-induced cranial nerve deficit is also rare, with only a few reported cases.

CASE REPORT

We report a case of a 61-year-old woman with a chief complaint of diplopia after she underwent epidural injection for chronic lumbar pain. Her examination was remarkable for a partial right oculomotor nerve palsy. We obtained a computed tomography brain scan, which revealed pneumocephalus. She was managed conservatively and reported complete symptom resolution after 2 weeks. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Pneumocephalus is an uncommon complication of epidural spinal injections. Emergency physicians should include this on the differential for a patient presenting with cranial nerve deficit after this procedure.

Intramuscular Nerve Distribution of the Inferior Oblique Muscle

Purpose: The intramuscular nerve distribution in the extraocular muscles is important for understanding their function. This study aimed to determine the intramuscular nerve distribution of the oculomotor nerve within the inferior oblique muscle (IO) using Sihler's staining.Method: Seventy-two IOs from 50 formalin-embalmed cadavers were investigated. The IO including its branch of the oculomotor nerve was finely dissected from its origin to its insertion point into the sclera. The total length of the muscle and its width were measured. The intramuscular nerve course was investigated after performing Sihler's staining, which is a whole-mount nerve-staining technique that stains the nerves while rendering other soft tissues either translucent or transparent.Results: The total length of the muscle and muscle width were 30.0 ± 2.8 mm (mean±standard deviation), 8.8 ± 1.2 mm, respectively. The oculomotor nerve enters the IO around the middle of the muscle and then divides into multiple smaller branches without distinct subdivisions. The intramuscular nerve distribution within the IO has a root-like arborization and supplies the entire width of the muscle. The Sihler's stained intramuscular nerve course (covering a length of 7.6 ± 1.2 mm) finishes around the distal one-third of the IO in gross observations.Conclusion: Sihler's staining is a useful technique for visualizing the gross nerve distribution of the IO. This new information about the nerve distribution and morphological features will improve the understanding of the biomechanics of the IO.

Don't Miss This! Red Flags in the Pediatric Eye Examination: Ophthalmoplegia in Childhood

Paralytic strabismus in children is rare, occurring in about 0.1% of children. This rate is far less common than the 3% rate usually noted for comitant strabismus. The relative rates of ocular motor pareses were fourth nerve palsies in 36%, sixth in 33%, third in 22%, with multiple ocular motor nerve palsies in 9%. In a single population series from Minnesota, few cases were associated with neoplasm. However, institutional case series reports a high rate of neoplasm for acquired third nerve and sixth nerve palsies after excluding trauma and congenital causes. Tumor is rare in children with fourth cranial nerve palsies, usually associated with other neurologic disease. Rare causes of external ophthalmoplegia, to be considered when the motility pattern is variable or not fitting an ocular motor nerve pattern, include myasthenia gravis and congenital fibrosis of the extraocular muscles. Myasthenia most often presents as ptosis with exotropia. Rarer still is involvement of the extraocular muscles in childhood thyroid disease.

Ocular Motor Cranial Nerve Palsy as an Indicator of Neglected Systemic Disease in Nigeria: Perspective from a Neuro-Ophthalmology Clinic

The aim of this article from Nigeria is to draw attention to public health issues in medical care using ocular motor cranial nerve palsy (OMCNP) presenting to a neuro-ophthalmology clinic as a case study. All patients presenting with OMCNP between November 2007 and October 2016 were retrospectively reviewed. Demographic details as well as information regarding the clinical presentation, clinical course, investigation, and treatment outcomes were extracted from case records. Phone calls were made to the contact numbers of patients who had been lost to follow-up. Data were analysed using SPSS version 22 (IBM, Corp. Armonk, NY, USA). Cranial nerve palsies other than oculomotor, trochlear, and abducens palsies were excluded. Fifty-nine patients, comprising 28 males and 31 females, were identified. Age range was 1-84 years (median 43.0 ± 19.7 years). Fifty-one cases (93.2%) were mono neuropathies, while four (6.8%) affected multiple nerves. Oculomotor nerve palsy was most common, accounting for 57.6% of cases. Microvascular angiopathy was the commonest identifiable cause (25.6%). Aetiology was not identified in 16 cases. There were three (5.1%) deaths. Undiagnosed systemic disease appears to be a major risk factor for this patient group in this African setting. Patient investigation was problematic. Poor patient compliance and follow-up resulted in preventable deaths. Neuro-ophthalmologists practicing in low resource settings should be aware of these risks.

Acute Oculomotor Nerve Palsy Caused by Compression from an Aberrant Posterior Communicating Artery

Oculomotor nerve palsy (ONP) is a rare neurological deficit associated with numerous underlying pathologies. Of these, aneurysm of the posterior communicating artery (PCOM) has been described due to the intimate association with the third cranial nerve in the basal cistern. Less described are other vascular abnormalities and their contribution to ONP. We describe a case of ONP thought to result from a PCOM aneurysm, per the associated magnetic resonance imaging (MRI) scan, yet found intraoperatively to be caused by a congenital vascular aberrancy. This is the first case, to our knowledge, of this presentation.

Sporadic Cisternal Oculomotor Nerve Schwannoma: A Rare Case with Review of Literature

Cranial nerve schwannomas usually arise from sensory nerve and the occurrence of schwannoma in a motor nerve is rare, especially in sporadic cases. Oculomotor nerve schwannomas (ONS) are rare and they are unique as they arise from motor nerve. ONS palsy may or may not be the presenting feature of oculomotor schwannoma. We present the case of a young male with ONS, presenting with oculomotor nerve palsy along with features of raised intracranial pressure. Oculomotor schwannoma is described in literature only as case reports, and oculomotor nerve is also a rare site for schwannoma as being a motor nerve. In this article, we describe a case of cisternal ONS with review of pertinent literature.

Spontaneous resolution of isolated neurogenic blepharoptosis after blunt trauma: A case report and literature review

RATIONALE

Complete isolated neurogenic blepharoptosis caused by blunt trauma is a sporadically reported rare entity and there is no consensus regarding the optimal treatment. We would like to report a rare case of isolated neurogenic blepharoptosis secondary to eyelid trauma with spontaneous recovery occurring within 4 weeks.

PATIENT CONCERNS

A previously healthy 47-year-old man presented with blepharoptosis in the right eye after eyelid trauma.

DIAGNOSIS

At presentation, visual acuity in both eyes was 20/20, and intraocular pressure was within the normal limits. Physical examination showed unilateral ptosis; magnetic resonance imaging (MRI) showed hematoma in the right frontal sinus. No intracranial lesions were observed and the pupillary reactions were normal. The remainder of the examination was unremarkable with full ocular motility. He was diagnosed with an isolated neurogenic blepharoptosis.

INTERVENTION AND OUTCOMES

He was managed conservatively without any specific treatment. Four weeks later, the patient had normal, symmetric lid height, and levator function was completely restored.

LESSONS

Isolated neurogenic blepharoptosis can be caused by blunt trauma, which might cause injury to the terminal branch of the oculomotor nerve. In this case, no special treatment was required, and complete resolution was achieved within 4 weeks.

Infantile Dermoid Cyst in the Lateral Wall of the Cavernous Sinus: A Case Report and Literature Review

Dermoid tumors originating from the cavernous sinus are typically intradural, and thus, presentation with ophthalmoplegia is uncommon. Infantile dermoid tumors originating from the interdural space of the lateral wall of the cavernous sinus are also very rare. We herein present a 4-year-old infantile case of a dermoid cyst that was embedded in the lateral wall of the cavernous sinus. The patient presented with oculomotor nerve palsy. Magnetic resonance image demonstrated a well-circumscribed oval lesion inside the lateral wall of the left cavernous sinus. The lesion had two solid components that were hyperintense on T1- and T2-weighted images and was associated with a cystic mass that included fluid with the same signal intensity as cerebrospinal fluid. Gross total removal via a frontotemporal approach was performed. The symptoms markedly recovered in the 6-month follow-up. To the best of our knowledge, there have only been two reports of infantile dermoid cysts in the lateral wall of the cavernous sinus. We herein describe their clinical characteristics with the previous review and introduce surgical tips for the resection.

Acute Transient Oculomotor Nerve Palsy from Presumed Cavernous Angioma in an Infant

Cavernous angiomas of the cranial nerves are extremely rare, and those of the oculomotor (third) cranial nerve are rarer still, with no previous cases having been reported in the literature. We report herein the first case of a presumed cavernous angioma involving the subarachnoid portion of the left third nerve presenting as an acute left third nerve palsy in an infant. The child was followed without intervention and the palsy completely resolved. Given the poor functional results with attempted surgical excision and the potential for spontaneous improvement in oculomotor nerve function, it is reasonable to follow patients with these lesions without intervention.

Angiographic Findings in the Tolosa-Hunt Syndrome and Resolution after Corticosteroid Treatment

The Tolosa-Hunt syndrome is a rare clinical condition characterized by painful opthalmoparesis associated with idiopathic granulomatous inflammation of the orbital apex and cavernous sinus. Historically, this condition was thought to result from arteritic changes in the internal carotid artery and cavernous sinus. Modern digital angiographic techniques were unavailable when THS was initially described, and few reports exist on its high-resolution angiographic findings. Painful ophthalmoparesis, especially of the oculomotor nerve, warrants vascular imaging because of the concern for an underlying aneurysm. Here, we describe angiographic findings of THS which may be useful for clinicians when encountering patients presenting with painful ophthalmoplegia.

Lessons from Amphioxus Bauplan About Origin of Cranial Nerves of Vertebrates That Innervates Extrinsic Eye Muscles

Amphioxus is the living chordate closest to the ancestral form of vertebrates, and in a key position to reveal essential aspects of the evolution of the brain Bauplan of vertebrates. The dorsal neural cord of this species at the larval stage is characterized by a small cerebral vesicle at its anterior end and a large posterior region. The latter is comparable in some aspects to the hindbrain and spinal cord regions of vertebrates. The rostral end of the cerebral vesicle contains a median pigment spot and associated rows of photoreceptor and other nerve cells; this complex is known as "the frontal eye." However, this is not a complete eye in the sense that it has neither eye muscles nor lens (only a primitive retina-like tissue). Cranial nerves III, IV, and VI take part in the motor control of eye muscles in all vertebrates. Using a recent model that postulates distinct molecularly characterized hypothalamo-prethalamic and mesodiencephalic domains in the early cerebral vesicle of amphioxus, we analyze here possible scenarios for the origin from the common ancestor of cephalochordates and vertebrates of the cranial nerves related with extrinsic eye muscle innervations. Anat Rec, 302:452-462, 2019. © 2018 Wiley Periodicals, Inc.

Asymptomatic Penetration of Oculomotor Nerve by Internal Carotid-Posterior Communicating Artery Aneurysm Presenting Pure Acute Subdural Hematoma: A Case Report

To present a unique case of the internal carotid artery-posterior communicating artery (ICA-PcomA) aneurysm penetrating the oculomotor nerve presenting a pure acute subdural hematoma (ASDH) without any oculomotor dysfunction. A 71-year-old woman presented with a sudden headache and drowsiness. She had no history of head trauma and did not manifest any neurological deficits including oculomotor nerve palsy. Computed tomography (CT) of her head revealed left ASDH. Subsequent CT angiography showed an aneurysm originating from the left ICA with an inferior projection having continuity with the hematoma. Intraoperative inspection revealed ASDH observed mainly in middle fossa and no subarachnoid hemorrhage, while the aneurysm was confirmed to split the oculomotor nerve and to be fixed with the middle fossa. The aneurysm was obliterated by direct clip application and the patient’s postoperative course was uneventful. Oculomotor nerve palsy is an important warning sign of imminent rupture of ICA-PcomA aneurysm. However, we should consider that the ICA-PcomA aneurysm could rupture causing ASDH without any oculomotor nerve palsy, even though the aneurysm penetrated the oculomotor nerve.

Ruptured posterior cerebral artery aneurysm presenting with a contralateral cranial nerve III palsy: A case report

Background:

Posterior cerebral artery aneurysms can frequently present with an ipsilateral cranial nerve III palsy.

Case Description:

We report the first case of a posterior cerebral artery aneurysm associated with a contralateral cranial nerve III palsy. A 64-year-old male presented with acute subarachnoid hemorrhage, Hunt and Hess grade 3, and a left-sided fixed and dilated pupil. Computed tomography scan showed hemorrhage, mainly within the left basal cisterns. Digital subtraction angiography revealed a right-sided P1–P2 junction aneurysm.

Conclusions:

This case demonstrates that, although the neurological exam can help pinpoint the location of a lesion, false localizing signs should be recognized.

Unilateral Oculomotor Nerve Palsy Following Campylobacter Infection: A Mild Form of Miller Fisher Syndrome without Ataxia

Unilateral oculomotor nerve palsy can result from various neurological disorders. We herein report the case of a 68-year-old man with complete unilateral oculomotor nerve palsy following campylobacter infection. Based on the antecedent infection and the patient's decreased tendon reflexes, incomplete Miller Fisher syndrome (MFS) without ataxia was suspected. His serum tested positive for anti-GQ1b antibodies. He recovered over a period of 87 days without immunotherapy. We conclude that incomplete MFS following campylobacter infection can cause unilateral oculomotor nerve palsy without ataxia. Mild MFS should be considered in patients presenting with unilateral isolated ophthalmoplegia and decreased tendon reflexes.

Ptosis as the only manifestation of diabetic superior division oculomotor nerve palsy: A case report

RATIONALE

Diabetic oculomotor nerve palsies, also called ischemic third nerve palsies, are the most common etiologic subset of oculomotor nerve palsy in adults. Diabetic oculomotor nerve palsies typically present with ptosis and diplopia, but pupillary function is often spared. The oculomotor nerve separates into superior division and inferior division, with the superior division innervating the superior rectus and levator palpebrae superioris. The diabetic oculomotor nerve palsy may affect isolated superior or inferior division of the oculomotor nerve, but diplopia usually exists.

PATIENT CONCERNS

A 56-year-old female was admitted to our hospital for acute onset right upper lid ptosis. The patient denied diplopia or other new focal neurologic symptoms. The neurological examination revealed ptosis of the right upper eyelid only, and other neurological examination revealed negative findings.

DIAGNOSES

The diagnosis of diabetes-associated oculomotor nerve palsy was made, with acute ptosis as its only manifestation.

INTERVENTIONS

We controlled her blood sugar aggressively with insulin.

OUTCOMES

After the hyperglycemia improved, the right side ptosis recovered partially within one week.

LESSONS

From this case, we suggest that when evaluating patients with acute onset ptosis as the only manifestation, diabetic-vasculopathic neuropathy should be considered. This case also implies that the most interior portion of the third cranial nerve may consist of nerve fibers mainly innervating the levator palpebrae superioris.

Compartmental Endoscopic Surgical Anatomy of the Inferior Intraconal Orbital Space

Objectives  This study aims to define the endoscopic anatomy of inferior intraconal space, in terms of its neurovascular structures and relationship to fixed anatomic landmarks. Design  A cadaveric anatomical study was conducted. Setting  This study was conducted at an academic cranial base center. Participants  Cadaveric subjects have been investigated. Main Outcome Measures  After dissection of the inferior intraconal space, the number and position of ophthalmic artery (OA) and oculomotor nerve (OMN) branches to the inferior rectus muscle (IRM) were quantified relative to the fixed landmark of the posterior maxillary wall. The point where the OMN branch to the inferior oblique muscle (IOM) crossed the lateral IRM margin was quantified. Results  A total of 18 OA branches were identified with a mean ± standard deviation of 2.6 ± 0.53 branches. The mean distance of the OA branch insertion from the posterior maxillary wall was 7.11 ± 5.65 mm. The average number of OMN branches to the IRM was 1.63 ± 0.74 with a mean insertion distance of 1.88 ± 1.89 mm. The OMN branch to the IOM crossed the lateral IRM margin 5.38 ± 5.42 mm from the posterior maxillary wall. Conclusions  This cadaveric study quantifies the variability of two critical neurovascular structures salient to endoscopic approaches to the inferior intraconal space, the OMN, and OA contributions to the IRM. Knowledge of the interrelationship between these structures is essential in safe technique for dissection.

Electrical stimulation promotes regeneration of injured oculomotor nerves in dogs

Functional recovery after oculomotor nerve injury is very poor. Electrical stimulation has been shown to promote regeneration of injured nerves. We hypothesized that electrical stimulation would improve the functional recovery of injured oculomotor nerves. Oculomotor nerve injury models were created by crushing the right oculomotor nerves of adult dogs. Stimulating electrodes were positioned in both proximal and distal locations of the lesion, and non-continuous rectangular, biphasic current pulses (0.7 V, 5 Hz) were administered 1 hour daily for 2 consecutive weeks. Analysis of the results showed that electrophysiological and morphological recovery of the injured oculomotor nerve was enhanced, indicating that electrical stimulation improved neural regeneration. Thus, this therapy has the potential to promote the recovery of oculomotor nerve dysfunction.

Bidirectional Synergistic Vergence

A 14-year-old boy presented with left ptosis and squint since his childhood. In primary position he had left hypotropia with ptosis (levator function 2 mm). With elevation of the right eye, the left eye depresses and adducts; with depression of the right eye, the left eye elevates and abducts. Forced duction test revealed no restrictive pattern. The synergistic divergence described in the literature was unidirectional and wholly compatible with inferior rectus co-contraction. But this case is bidirectional, and the aberrant upward movement cannot be explained by rectus muscle co-contraction. The two vertical rectus muscles show reciprocal misinnervation, or this effect could be coming from co-contraction of one of the oblique muscles for the movement in one direction.

Detection of third and sixth cranial nerve palsies with a novel method for eye tracking while watching a short film clip

OBJECT

Automated eye movement tracking may provide clues to nervous system function at many levels. Spatial calibration of the eye tracking device requires the subject to have relatively intact ocular motility that implies function of cranial nerves (CNs) III (oculomotor), IV (trochlear), and VI (abducent) and their associated nuclei, along with the multiple regions of the brain imparting cognition and volition. The authors have developed a technique for eye tracking that uses temporal rather than spatial calibration, enabling detection of impaired ability to move the pupil relative to normal (neurologically healthy) control volunteers. This work was performed to demonstrate that this technique may detect CN palsies related to brain compression and to provide insight into how the technique may be of value for evaluating neuropathological conditions associated with CN palsy, such as hydrocephalus or acute mass effect.

METHODS

The authors recorded subjects' eye movements by using an Eyelink 1000 eye tracker sampling at 500 Hz over 200 seconds while the subject viewed a music video playing inside an aperture on a computer monitor. The aperture moved in a rectangular pattern over a fixed time period. This technique was used to assess ocular motility in 157 neurologically healthy control subjects and 12 patients with either clinical CN III or VI palsy confirmed by neuro-ophthalmological examination, or surgically treatable pathological conditions potentially impacting these nerves. The authors compared the ratio of vertical to horizontal eye movement (height/width defined as aspect ratio) in normal and test subjects.

RESULTS

In 157 normal controls, the aspect ratio (height/width) for the left eye had a mean value ± SD of 1.0117 ± 0.0706. For the right eye, the aspect ratio had a mean of 1.0077 ± 0.0679 in these 157 subjects. There was no difference between sexes or ages. A patient with known CN VI palsy had a significantly increased aspect ratio (1.39), whereas 2 patients with known CN III palsy had significantly decreased ratios of 0.19 and 0.06, respectively. Three patients with surgically treatable pathological conditions impacting CN VI, such as infratentorial mass effect or hydrocephalus, had significantly increased ratios (1.84, 1.44, and 1.34, respectively) relative to normal controls, and 6 patients with supratentorial mass effect had significantly decreased ratios (0.27, 0.53, 0.62, 0.45, 0.49, and 0.41, respectively). These alterations in eye tracking all reverted to normal ranges after surgical treatment of underlying pathological conditions in these 9 neurosurgical cases.

CONCLUSIONS

This proof of concept series of cases suggests that the use of eye tracking to detect CN palsy while the patient watches television or its equivalent represents a new capacity for this technology. It may provide a new tool for the assessment of multiple CNS functions that can potentially be useful in the assessment of awake patients with elevated intracranial pressure from hydrocephalus or trauma.

Intracranial tuberculoma presenting as an isolated oculomotor nerve paresis

BACKGROUND

The differential diagnosis of isolated oculomotor nerve paresis ranges from benign to potentially lethal pathologies. Intracranial tuberculosis (TB), as in the case of this patient, carries a high morbidity and mortality. Early diagnosis is crucial to improve patient outcomes.

CASE REPORT

We present the case of a 46-year-old man with a chief complaint of 5 days of diplopia. His examination was remarkable for right inferolateral exotropia and weakness of the right medial rectus. Due to the neurologic findings, we obtained a computed tomography brain scan, which revealed a ring-enhancing lesion within the central midbrain with vasogenic edema causing mass effect on the cerebral aqueduct. Further evaluation revealed tuberculosis (TB) as the underlying etiology. He was placed on steroids and a four-drug anti-TB regimen with resultant improvement of his symptoms. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Intracranial tuberculoma can present with an isolated oculomotor nerve paresis in the absence of pulmonary or systemic symptoms. This case emphasizes the importance of maintaining a broad differential when investigating isolated oculomotor nerve paresis.

Whole courses of the oculomotor, trochlear, and abducens nerves, identified in sectioned images and surface models

In medicine, the neuroanatomy of the oculomotor (III), trochlear (IV), and abducens nerves (VI) is learned essentially by cadaver dissection, histological specimens, and MRI. However, these methods have many limitations and it is necessary to compensate for the insufficiencies of previous methods. The aim of this research was to present sectioned images and surface models that allow the whole courses of III, IV, and VI and circumjacent structures to be observed in detail. To achieve this, the structures of whole courses of III, IV, and VI were traced on the sectioned images, and surface models of the structures were reconstructed. As a result, nucleus of III, Edinger-Westphal nucleus, nucleus of IV, and nucleus of VI and their fibers were identified on brainstem in the sectioned images. In the sectioned images, III, IV, and VI passed both sides of the cavernous sinus and entered at the orbit through the superior orbital fissure. In the sectioned images, III, IV, and VI innervated extraocular muscles in orbit. In surface models, the whole courses of III, IV, and VI and circumjacent structures could be explored freely three-dimensionally. The greatest advantage of the sectioned images was that they allowed the whole courses of III, IV, and VI and circumjacent structures to be observed as real colored in an unbroken line. In addition, the surface models allowed the stereoscopic shapes and positions of III, IV, and VI to be comprehended. The sectioned images and surface models could be applied for medical education purposes or training tools. All data generated during this study is available free of charge at anatomy.dongguk.ac.kr/cn/.

Unruptured internal carotid-posterior communicating artery aneurysm splitting the oculomotor nerve: a case report and literature review

Objective To report a rare case of unruptured internal carotid-posterior communicating artery (IC-PC) aneurysm splitting the oculomotor nerve treated by clipping and to review the previously published cases.

Case Presentation A 42-year-old man suddenly presented with left oculomotor paresis. Three-dimensional digital subtraction angiography (3D DSA) demonstrated a left IC-PC aneurysm with a bulging part. During surgery, it was confirmed that the bulging part split the oculomotor nerve. After the fenestrated oculomotor nerve was dissected from the bulging part with a careful microsurgical technique, neck clipping was performed. After the operation, the symptoms of oculomotor nerve paresis disappeared within 2 weeks.

Conclusions We must keep in mind the possibility of an anomaly of the oculomotor nerve, including fenestration, and careful observation and manipulation should be performed to preserve the nerve function during surgery, even though it is very rare.

Oculomotor nerve schwannoma associated with acute hydrocephalus: case report

A 37-year-old woman presented with an extremely rare large oculomotor schwannoma associated with acute hydrocephalus manifesting as semicoma and anisocoria. Brain computed tomography and magnetic resonance imaging revealed a tumor in the oculomotor cistern. Cerebral angiography revealed separation of the posterior cerebral artery (PCA) and superior cerebellar artery (SCA). The tumor was removed subtotally by two stage surgery. Histological examination revealed ordinary schwannoma. The diagnosis of oculomotor nerve schwannoma was based on the intraoperative finding of the tumor origin in the oculomotor nerve. Oculomotor nerve schwannoma can cause acute hydrocephalus and manifest as impaired consciousness. The angiographical separation of the PCA and SCA was very useful for the preoperative diagnosis of oculomotor nerve schwannoma.

Factors Predicting the Oculomotor Nerve Palsy following Surgical Clipping of Distal Vertebrobasilar Aneurysms: A Single-Institution Experience

Background The aim of our study was to identify various clinical and radiologic factors that correlate with the oculomotor nerve palsy following clipping of distal vertebrobasilar aneurysms. Methods A total of 48 patients with 51 aneurysms were included in this retrospective study . Patient's age, gender, size, location, and projection of the aneurysm, preoperative Hunt and Hess (H&H) grade, presence of subarachnoid hemorrhage (SAH), temporary clipping, preoperative third nerve palsy, and Glasgow Outcome Scale were included in the model for analysis. Results A total of 15 patients (31.25%) developed oculomotor nerve palsy following clipping of basilar apex aneurysms. 38 patients (79.2%) presented with SAH and 35 patients (72.9%) had poor H&H grades at presentation. The size of the aneurysm (p = 0.03), preoperative H&H grade (p = 0.04), preoperative oculomotor nerve dysfunction (p = 0.007), and projection of an aneurysm (p = 0.004) had shown a significant correlation with the oculomotor nerve palsy. The size of the aneurysm (p = 0.030, odds ratio: 0.381; 95% confidence interval, 0.175-0.827] was an independent predictor of postoperative nerve dysfunction. Conclusion The size of the aneurysm, clinical grade at presentation, and projection of the aneurysm correlated with the oculomotor nerve dysfunction following clipping. These clinical and radiologic parameters can be used to predict the oculomotor nerve outcome.

Resection of an oculomotor nerve cavernous angioma

BACKGROUND

Cavernous angiomas (CAs) of cranial nerves are rare, and their occurrence on the third cranial nerve is particularly rare. Surgical management of such CAs involving the third nerve is controversial. We describe a case of a symptomatic CA of the oculomotor nerve and review the literature in order to ascertain the relevance of surgical intervention.

CASE DESCRIPTION

A 71-year-old male patient presented with a 2-month history of progressive oculomotor nerve paralysis. CA of the oculomotor nerve was suspected on magnetic resonance imaging (MRI). The patient underwent complete resection of the CA through a subtemporal approach, preserving the integrity of the nerve. Histopathological analysis confirmed the diagnosis of CA. Despite optimal resection, the patient did not improve postoperatively.

CONCLUSION

CAs of cranial nerves can cause rapid or progressive neurological deterioration. Whereas delayed treatment often leads to irreversible deficits, early nerve-sparing surgical excision of the CAs may potentially restore function.

Compartmental endoscopic surgical anatomy of the medial intraconal orbital space

BACKGROUND

Surgical management of intraconal pathology represents the next frontier in endoscopic endonasal surgery. Despite this, the medial intraconal space remains a relatively unexplored region, secondary to its variable and technically demanding anatomy. The purpose of this study is to define the neurovascular structures in this region and introduce a compartmentalized approach to enhance surgical planning.

METHODS

This study was an institutional review board (IRB)-exempt endoscopic anatomic study in 10 cadaveric orbits. After dissection of the medial intraconal space, the pattern and trajectory of the oculomotor nerve and ophthalmic arterial arborizations were analyzed. The position of all vessels as well as the length of the oculomotor trunk and branches relative to the sphenoid face were calculated.

RESULTS

A mean of 1.5 arterial branches were identified (n = 15; range, 1-4) at a mean of 8.8 mm from the sphenoid face (range, 4-15 mm). The majority of the arteries (n = 7) inserted adjacent to the midline of medial rectus. The oculomotor nerve inserted at the level of the sphenoid face and arborized with a large proximal trunk 5.5 ± 1.1 mm in length and multiple branches extending 13.2 ± 2.7 mm from the sphenoid face. The most anterior nerve and vascular pedicle were identified at 17.0 and 15.0 mm from the sphenoid face, respectively.

CONCLUSION

The neurovascular supply to the medial rectus muscle describes a varied but predictable pattern. This data allows the compartmentalization of the medial intraconal space into 3 zones relative to the neurovascular supply. These zones inform the complexity of the dissection and provide a guideline for safe medial rectus retraction relative to the fixed landmark of the sphenoid face.

Microsurgical Relations between Internal Carotid Artery-Posterior Communicating Artery (ICA-PComA) Segment Aneurysms and Skull Base: An Anatomoclinical Study

Purpose The study of the clinical, anatomic, imaging, and microsurgical characteristics of the aneurysms of the internal carotid-posterior communicating artery (ICA-PComA) segment and their relationships with the skull base structures. Methods The anatomic relationships of PComA with neurovascular elements and skull base structures were studied in cadavers. The clinical, imaging, and microsurgical findings of 84 microsurgically treated ICA-PComA aneurysms compiled in a prospective database were reviewed. Results The most important anatomic relations of the PComA and ICA-PComA aneurysms are with the oculomotor nerve around the oculomotor triangle that forms the roof of the cavernous sinus. Aneurysms of the ICA-PComA are classified according to the orientation of the aneurysmal sac in infratentorial, supratentorial, and tentorial. Infratentorial aneurysms frequently present with subarachnoid hemorrhage (SAH) and oculomotor nerve paralysis. They have relations with skull base structures that often make it necessary to totally or partially resect the anterior clinoid process (6.7%) or anterior petroclinoid dural fold (15%). Supratentorial aneurysms course with SAH and without oculomotor nerve involvement, but they often are associated with intracranial hematoma. Conclusion ICA-PComA aneurysms have complex anatomic relations. The orientation of the aneurysmal fundus induces relevant differences in the anatomic relations, clinical presentation, and microsurgical approach to ICA-PComA aneurysms.

A standardized method to create peripheral nerve injury in dogs using an automatic non-serrated forceps

This study describes a method that not only generates an automatic and standardized crush injury in the skull base, but also provides investigators with the option to choose from a range of varying pressure levels. We designed an automatic, non-serrated forceps that exerts a varying force of 0 to 100 g and lasts for a defined period of 0 to 60 seconds. This device was then used to generate a crush injury to the right oculomotor nerve of dogs with a force of 10 g for 15 seconds, resulting in a deficit in the pupil-light reflex and ptosis. Further testing of our model with Toluidine-blue staining demonstrated that, at 2 weeks post-surgery disordered oculomotor nerve fibers, axonal loss, and a thinner than normal myelin sheath were visible. Electrophysiological examination showed occasional spontaneous potentials. Together, these data verified that the model for oculomotor nerve injury was successful, and that the forceps we designed can be used to establish standard mechanical injury models of peripheral nerves.

Posterior clinoidectomy: dural tailoring technique and clinical application

The posterior clinoid process, a bony prominence at the superolateral aspect of the dorsum sellae, has a strategic importance in a transcavernous approach to basilar tip aneurysms. To further optimize this microsurgical technique during posterior clinoidectomy, we performed a cadaveric study of this regional anatomy, describe a technique called dural tailoring, and report initial results in the surgical treatment of upper basilar artery (BA) aneurysm. After 10 adult cadaver heads (silicone-injected) were prepared for dissection, a posterior clinoidectomy with dural tailoring was performed. The dura overlying the upper clivus was coagulated with bipolar electrocoagulation and incised. Stripping dura off the clivus and lateral reflection then exposed the ipsilateral posterior clinoid process and dorsum sellae, thus creating a dural flap. Posterior clinoidectomy with dural tailoring was then used in seven patients with upper BA aneurysms. Our stepwise modification of the posterior clinoidectomy with dural tailoring created a flap that afforded protection of the cavernous sinus and oculomotor nerve. During surgery, there were no recorded intraoperative injuries to neurovascular structures. One patient died postoperatively from morbidity related to severe-grade subarachnoid hemorrhage. Postoperative oculomotor nerve palsy occurred in 3 patients (43%). In all cases, the nerve was anatomically preserved and partial to complete recovery was recorded during the first postoperative year. This technique effectively provided exposure of retrosellar upper basilar aneurysms in seven patients (basilar tip 43% and superior cerebellar artery aneurysms 57%). Outcomes and safety are at least equivalent to or better than basilar aneurysm surgery performed without surgical adjuncts, presumably a less complex subset.

Cranial Nerves III, IV, and VI: Oculomotor Function

Motor activity affecting the direction of gaze, the position of the eyelids, and the size of the pupils are served by cranial nerves III, IV, and VI. Unusual oculomotor activity is often encountered in psychiatric patients and can be quite informative. Evaluation techniques include casual observation and simple tests that require no equipment in addition to the sophisticated methods used in specialty clinics and research labs. This article reviews pupil size, extraocular movements, nystagmus, lid retraction, lid lag, and ptosis. Beyond screening for diseases and localizing lesions, these tests yield useful information about the individual's higher cortical function, extrapyramidal motor functioning, and toxic/pharmacologic state.

Ruptured anterior communicating artery aneurysm causing bilateral oculomotor nerve palsy: a case report

A rare case of bilateral third cranial nerve palsy due to a ruptured anterior communicating artery aneurysm is presented. A 68-yr-old woman was semicomatose with bilaterally fixed dilated pupil, abducted eyes, and ptosis. A computed tomography demonstrated extensive hemorrhage spreading around the both Sylvian and interhemisheric fissure without focal mass effect. Intracranial pressure via extraventricular drainage before surgery was 15-50 mmHg. Three months later, brain MRI showed infarction of left posterior cerebral artery territory and lacuna infarction of the pons. Eleven months after aneurysm repair, nerve palsy improved slowly and recovered partially. The patient communicated well with simple words. The author reviewed and discussed the possible mechanism of this rare neuro-ophthalmological manifestation in view of a false localizing sign.