Trochlear Nerve Research Articles

Extracranial transport of brain lymphatics via cranial nerve in human

Extracranial waste transport from the brain interstitial fluid to the deep cervical lymph node (dCLN) is not extensively understood. The present study aims to show the cranial nerves that have a role in the transport of brain lymphatics vessels (LVs), their localization, diameter, and number using podoplanin (PDPN) and CD31 immunohistochemistry (IHC) and Western blotting. Cranial nerve samples from 6 human cases (3 cadavers, and 3 autopsies) were evaluated for IHC and 3 autopsies for Western blotting. The IHC staining showed LVs along the optic, olfactory, oculomotor, trigeminal, facial, glossopharyngeal, accessory, and vagus nerves. However, no LVs present along the trochlear, abducens, vestibulocochlear, and hypoglossal nerves. The LVs were predominantly localized at the endoneurium of the cranial nerve that has motor components, and LVs in the cranial nerves that had sensory components were present in all 3 layers. The number of LVs accompanying the olfactory, optic, and trigeminal nerves was classified as numerous; oculomotor, glossopharyngeal, vagus, and accessory was moderate; and facial nerves was few. The largest diameter of LVs was in the epineurium and the smallest one was in the endoneurium.The majority of Western blotting results correlated with the IHC. The present findings suggest that specific cranial nerves with variable quantities provide a pathway for the transport of wastes from the brain to dCLN. Thus, the knowledge of the transport of brain lymphatics along cranial nerves may help understand the pathophysiology of various neurological diseases.

Basic and Advanced Techniques of Anastomosis in Deep Surgical Fields:STA-SCA Anastomosis

This article detailly describes the subtemporal-transtentorial STA-SCA bypass technique. Through temporal base drilling, copious cerebrospinal fluid evacuation before retraction, and sufficient retraction of the temporal lobe preserving the veins of the temporal base would be primodial to obtain an appropriate surgical field. Refrection of the tentrial free edge and identification of recipient SCA posterior to the entry point of the trochlear nerve into the cavernous sinus is a micro-anatomical key. Bilateral bayonet-type needle holders and forceps should be used not to shadow the surgical corridor with one's hands.

Evolution and development of extraocular motor neurons, nerves and muscles in vertebrates

The purpose of this review is to analyze the origin of ocular motor neurons, define the pattern of innervation of nerve fibers that project to the extraocular eye muscles (EOMs), describe congenital disorders that alter the development of ocular motor neurons, and provide an overview of vestibular pathway inputs to ocular motor nuclei. Six eye muscles are innervated by axons of three ocular motor neurons, the oculomotor (CNIII), trochlear (CNIV), and abducens (CNVI) neurons. Ocular motor neurons (CNIII) originate in the midbrain and innervate the ipsilateral orbit, except for the superior rectus and the levator palpebrae, which are contralaterally innervated. Trochlear motor neurons (CNIV) originate at the midbrain-hindbrain junction and innervate the contralateral superior oblique muscle. Abducens motor neurons (CNVI) originate variously in the hindbrain of rhombomeres r4–6 that innervate the posterior (or lateral) rectus muscle and innervate the retractor bulbi. Genes allow a distinction between special somatic (CNIII, IV) and somatic (CNVI) ocular motor neurons. Development of ocular motor neurons and their axonal projections to the EOMs may be derailed by various genetic causes, resulting in the congenital cranial dysinnervation disorders. The ocular motor neurons innervate EOMs while the vestibular nuclei connect with the midbrain-brainstem motor neurons.

Selective plication and grading of plication for correction of torsion in superior oblique palsy

Abstract: Acquired palsy of the trochlear nerve has been associated with closed-head injuries. We report the case of a 33-year-old male patient, who presented with complaints of torsional diplopia in the straight gaze which increased in the down gaze following head trauma. After a detailed ophthalmic evaluation, the patient was diagnosed with bilateral superior oblique (SO) palsy causing torsional diplopia. To counteract excyclotorsion, we have plicated the anterior one-third of the fibers of the SO in both eyes. Postoperatively, the patient was diplopia free and orthophoric, which maintained up to 3-month follow-up. Correction of excyclotorsion by selective plication of anterior fibers of the SO has already been reported in literature. However, the amount of plication to be performed for various degrees of torsion has not been appropriately described in the previously reported articles. We aim to improve the efficacy of plication anterior fibers of the SO by objective gradation.

Pituitary metastasis arising from hepatocellular carcinoma: a case report and update of the literature.

Hepatocellular carcinoma (HCC) is the sixth most common neoplasia and the third leading cause of cancer-associated deaths worldwide. Most cases arise in patients with cirrhosis, and early detection through periodic screening can make it potentially curable. The presence of extrahepatic metastases (EHM) affects treatment decisions and curability. The lungs are the most common site for EHM, followed by lymph nodes, bones, and the adrenal glands. Interestingly, approximately only 15 cases of HCC metastasizing to the pituitary gland have been reported so far.The most common symptoms of pituitary metastasis (PM) arising from HCC are nerve palsies affecting the third, fourth, and sixth cranial nerves. Other symptoms, such as diabetes insipidus or pituitary insufficiencies, are present in a minority of cases. Detecting PM is difficult given its rarity. Gold-standard treatments for these patients have not yet been established, but the prognosis is dismal, with a median overall survival of only 4.5 months. In this paper, we present an interesting case of PM as the first symptom of an HCC in a 75-year-old female. We also present an overview of all cases reported to date with emphasis on symptom presentation and survival after diagnosis.Given the improvement of systemic therapy, more cases are diagnosed in both oligometastatic and palliative conditions. Therefore, better approaches and treatment modalities for extrahepatic metastases due to HCC should be defined.

Microsurgical Procedures of Microvascular Decompression for Trigeminal Neuralgia

Microvascular decompression for trigeminal neuralgia was successfully performed following the secure surgical steps. The most crucial step involves creating a safe operative field in the dural opening. The petrotentorial junction should be identified without cerebellar retraction before proceeding to the deeper areas. Dissecting the petrosal vein and opening the horizontal fissure contributed to the expansion of the operative field. Bleeding often occurs from the dorsal cerebellar bridging vein and junction of the petrosal vein into the superior petrosal sinus. Transposition of the most common offenders, the superior and anterior inferior cerebellar arteries, is effectively achieved by dissecting both the proximal and distal sides of the neurovascular compression site. Teflon should be placed at a sufficient distance to prevent contact with the nerve, which can lead to recurrence. Treating vertebrobasilar artery-related cases is challenging and involves the risk of cranial nerve injuries. Multiple offending vessels are commonly involved. In such cases, it is essential to be aware of the course of the trochlear and abducens nerves during decompression. Applying the most effective and least risky maneuver is necessary for treating cases involving the vertebrobasilar artery.

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

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

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

Congenital trochlear nerve palsy is the most common cause of vertical strabismus. The goal of this study was to investigate surgical outcomes after superior oblique tendon plication with or without inferior oblique recession in children and adults with unilateral congenital trochlear nerve palsy. Data and outcomes were collected in patients with a diagnosis of unilateral congenital superior oblique palsy during a retrospective single-center study conducted at the University Hospital of Tours. A reproducible, standard ophthalmological and oculomotor examination was performed pre- and postoperatively at 1 year, including presence or absence of diplopia, vertical and horizontal deviations, and compensatory head posture. Surgical success, defined as an endpoint including absence of diplopia in primary position, absence of head tilt, and vertical deviation at distance fixation<5 prism diopters (PD), was analyzed. A total of fifty-seven patients (median [IQR] age of 11 years [5-42]) were analyzed. Patients experienced a significant reduction in vertical distance and near deviations (p<0.001), compensatory head tilt (p<0.001), and diplopia after surgery (p<0.001). Surgical success was higher in adults (17/24, 70.8%) than in children (15/33, 45.5%), although this did not reach statistical significance (p=0.0657). This study suggests that plication of the superior oblique muscle tendon, with or without recession of the inferior oblique muscle, can be effective in treating unilateral congenital trochlear nerve palsy. Further studies are necessary to compare surgical procedures and investigate their efficacy in adults compared to children in the short and long term.

The Use of the Suboccipital Transtentorial Approach to the Posterior Inferior Incisural Space.

Objective To describe our experience with the microsurgical technique of the suboccipital transtentorial (SOTT) approach in the removal of posterior fossa lesions located in the posterior incisural space. Method Between 2002 and 2020 we reviewed all patients who underwent microsurgical resection of lesions of the posterior incisural space at the Department of Neurosurgery, Essex Neuroscience Centre, London, England (eight patients, male to female 3:5, mean age: 51, range 35-69). We describe the preoperative symptoms, radiological findings, surgical techniques, histologyand postoperative outcomes in this cohort of patients. Results Eight patients with tumours located in the posterior incisural space underwent surgery during the study period including four meningiomas (50%), two haemangioblastomas (25%), one metastasis (13%) and one giant prolactinoma (13%). Gross or near total resection was achieved in six patients (75%): the giant prolactinoma could not be radically removed and one of the meningiomas required a small fragment to be left in place to protect the Vein of Galen.No patient developed a visual field deficit due to occipital lobe retraction.One patient developed a temporary trochlear nerve palsy (13%). Five patients had mild disability (Glasgow Outcome Scale (GOS) = 5), and four had moderate disability (GOS = 4). Conclusion In our series, the SOTT approach provided excellent access for all cases of tumours in the posterior incisural space. The tumour's size and relationship to the deep venous system contributed to the choice of approach and in one patient who had previously undergone surgery via the supracerebellar route, the SOTT approach enabled the avoidance of gliotic scar tissue. Success is dependent on careful case selection, though from our series of 8 patients, we conclude that this approach allows safe access to the posterior incisural space, with acceptable outcomes with regard to postoperative disability and cranial nerve palsy. As such, the approach should be in the armamentarium of any neurosurgeon who regularly deals with posterior fossa pathology.

Trapping and side-to-end superior cerebellar artery to superior cerebellar artery bypass for treatment of fusiform superior cerebellar artery aneurysm

We describe the technical nuances of in-situ bypass for treatment of a fusiform superior cerebellar artery (SCA) aneurysm via surgical trapping and a side-to-end in-situ bypass between duplicated SCAs. Our patient is a 40-year-old male who presented with an incidental aneurysm of the proximal right superior cerebellar artery (SCA). Formal angiography was performed that demonstrated a fusiform morphology of the aneurysm, as well as a duplicated SCA on that side. After extensive counseling, the patient elected to undergo surgical clip reconstruction with possible bypass. A large frontotemporal craniotomy was performed and a combined transsylvian-subtemporal approach to the ventral anterolateral brainstem was performed. After identifying the aneurysm, the tentorium was incised posterior to the insertion of the trochlear nerve to widen the operative field. An end-to-side anastomosis between the duplicated SCAs was performed, followed by trapping of the diseased arterial segment. The patient had an oculomotor nerve palsy post-operatively, however this resolved by his six-month follow-up. In-situ bypass is a viable technique for revascularizing the SCA territory during clip reconstruction of fusiform aneurysms. A duplicated SCA allows for an SCA to SCA bypass. Incising the tentorium can increase visualization of donor and recipient vessels and facilitate performance of the anastomosis.

Maxillary Sinus Carcinoma Presenting as Trochlear Nerve Palsy

We present a case of 21-year old gentleman presented with diplopia for last 4 months. There was history of protrusion of left eye ball, abnormal head posture causing head tilt and turning face towards right side and a painless lump in mouth over hard palate on left side. On examination, there was torticollis of the head with proptosis and partial ptosis of the left eye. There was impairment of intorsion, depression and adduction of the left eye with binocular diplopia which worsened when the left eye was directed downwards and medially. There was sensory loss in ophthalmic and maxillary divisions of the left Trigeminal nerve. CT scan of the paranasal sinuses revealed a locally aggressive mass in the left maxillary sinus with erosion and extension to left temporal bone. Biopsy confirmed it as Maxillary Sinus Carcinoma and a multidisciplinary management with ENT, neurosurgery and oncology was planned.

Recovery of Third, Fourth, and Sixth Cranial Nerve Palsies in Pituitary Adenoma and Meningioma Patients.

This retrospective, observational cohort study aimed to determine recovery rate and recovery time of ocular motor nerve palsies (OMP) of third (CN III), fourth (CN IV), or sixth cranial nerves (CN VI)-and associated prognostic factors-in meningioma and pituitary adenoma (PA) patients. A total of 25 meningioma (28 eyes) and 33 PA patients (36 eyes), treated at the Leiden University Medical Center in the Netherlands from January 1, 1978 to January 31, 2021, were included. OMPs were evaluated according to a newly created recovery scale using on-clinical and orthoptic examinations, which were performed every 3-4 months until palsy recovery, or at 18 months follow-up. Recovery rates of CN III (meningioma 23.5% vs PA 92.3%), CN IV (meningioma 20% vs PA 100%), and CN VI (meningioma 60% vs PA 100%) palsies were observed at 18 months follow-up, with differences between the 2 tumor types being observed in the treated patients only. Median recovery time of all OMPs combined was significantly longer in meningioma patients (37.9 ± 14.3 months vs 3.3 ± 0.1 months; P < 0.001). No significant protective or risk factors for recovery rate or time were identified. OMP recovery rates in treated patients were more favorable in patients with PA compared with patients with meningiomas, independent of OMP cause. With these new insights in OMP recovery, more accurate prognoses and appropriate follow-up strategies can be determined for meningioma and PA patients with OMPs.

The Superior Cerebellar Artery: Variability and Clinical Significance.

The superior cerebellar artery (SCA) arises from the distal part of the basilar artery and passes by the oculomotor, trochlear, and trigeminal nerves. SCA is known to play a crucial role in the development of trigeminal neuralgia. However, due to its anatomical variability, it may also trigger other neurovascular compression (NVC), including hemifacial spasm, oculomotor nerve palsy, and ocular neuromyotonia. Additionally, it may be associated with ischemic syndromes and aneurysm development, highlighting its clinical significance. The most common anatomical variations of the SCA include duplication, a single vessel origin from the posterior cerebral artery (PCA), and a common trunk with PCA. Rarely observed variants include bifurcation and origin from the internal carotid artery. Certain anatomical variants such as early bifurcation and caudal course of duplicated SCA trunk may increase the risk of NVC. In this narrative review, we aimed to examine the impact of the anatomical variations of SCA on the NVCs based on papers published in Pubmed, Scopus, and Web of Science databases with a snowballing approach. Our review emphasizes the importance of a thorough understanding of the anatomical variability of SCA to optimize the management of patients with NVCs associated with this artery.

Excision of massive orbital schwannoma through anterior orbital approach

Orbital schwannomas are rare, benign, slowly progressing, encapsulated tumors arising from Schwann cells of the peripheral sheath of the third, fourth, and sixth cranial nerves and ciliary ganglion. The present case is of a 32-year-old male with painless protrusion of left eye for 4 years. It was radiologically diagnosed as retro-orbital hemangioma, but histopathologic examination of the orbital tumor showed orbital schwannoma. The rarity of orbital schwannomas among orbital tumors and improvement in vision along with retained eyelid functions despite excision of a massive tumor make this a unique case.

Etiology of Isolated Third, Fourth, and Sixth Cranial Nerve Palsies with a Cancer History

Purpose: To investigate the causes of isolated ocular motor nerve palsy in patients with a history of cancer.Methods: The charts of 30 patients with cancer diagnosed with isolated acquired third, fourth, and sixth cranial nerve palsies from March 2013 to December 2021 were retrospectively reviewed. Sex, age of onset, underlying disease and causes of cranial nerve palsy were analyzed.Results: Sixth cranial nerve palsy (n = 18, 60.0%) was the most common. Brain metastasis (n = 13, 43.3%) was the most common etiology, followed by microvascular causes (n = 11, 36.7%), radiation-induced neuropathy (n = 2, 6.7%), and undetermined (n = 4, 13.3%). Among the 13 patients with palsies due to brain metastasis, only one (7.7%) had been in complete remission for more than 1 year. Of the remaining 17 patients with other causes, seven (41.2%) had been in complete remission of a previously diagnosed cancer for more than 1 year.Conclusions: In patients with a history of cancer, cranial nerve palsy due to brain metastasis was the most common cause, and it was more likely if the primary cancer had not been in remission for more than 1 year. Brain magnetic resonance imaging should be performed as soon as possible to confirm brain metastasis and a differential diagnosis including various other causes is also important.

From WEMINO To WEBINO With Unilateral LMN Facial Palsy (P5-4.002)

<h3>Objective:</h3> To describe a case of progression from apparent trochlear nerve palsy, to wall-eyed monocular internuclear ophthalmoplegia (WEMINO), to wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) with unilateral lower motor neuron (LMN) facial palsy. <h3>Background:</h3> Various descriptions of INO with cranial nerve palsies are in the literature, but we report a patient with a remarkably instructive stepwise evolution. <h3>Design/Methods:</h3> Review of records of a patient with diplopia at our institution. <h3>Results:</h3> A 42-year-old woman presented acutely with oblique binocular diplopia worsening on right gaze and left head tilt, with left hypertropia. Trochlear nerve palsy was suspected but contrasted MRI brain with orbits, and initial CSF testing were unrevealing. On day 3, the hypertropia partly improved but she developed left eye adduction deficit. Given the fluctuation, myasthenia gravis was considered high in the differential diagnosis while test results were awaited. On day 7, she developed LMN left facial palsy and bilateral adduction deficit with abducting eye nystagmus, leading to the realization that a single progressing lesion in the pontine tegmentum could explain her entire sequence of events. Repeat MRI confirmed a minute enhancing lesion in the floor of the fourth ventricle corresponding to the dorsomedial surface of the left facial colliculus and bilateral medial longitudinal fasciculi (MLF), likely of demyelinating etiology. Her pending CSF tests returned with 7 oligoclonal bands. She received intravenous methylprednisolone and her symptoms nearly resolved by day 14. <h3>Conclusions:</h3> This patient presented with evolving symptoms that appeared to localize to the trochlear nerve initially, but lacked imaging correlate. It is clear in retrospect that her initial presentation represented a skew deviation from early INO, progressing to WEMINO and eventually WEBINO with unilateral fascicular facial palsy. The anatomical correlate was confirmed on repeated imaging. Her clinical course beautifully illustrates the importance of lesion localization for etiological diagnosis. <b>Disclosure:</b> Dr. Senthamarai Siddharthan has nothing to disclose. Dr. Witt has nothing to disclose. Dr. Kini has nothing to disclose. Dr. Vasireddy has nothing to disclose. The institution of Dr. Mathur Kumaraswamy has received research support from Woolsey Pharmaceuticals.

Clinical Features of Pituitary or Parasellar Tumor Onset with Cranial Nerve Palsy: Surgical Intervention Considerations

This study aimed to clarify the symptoms of pituitary or parasellar tumor onset with cranial nerve palsy (CNP) and to improve our knowledge of this rare symptom and its most appropriate treatment. Among 1281 patients with pituitary or parasellar tumors surgically treated from 2003 to 2020, 30 cases (2.34%; 15 men and 15 women; mean age: 55.6years, range: 6-83years) first presenting with CNP were reviewed to evaluate the neurological symptoms, histological diagnosis, interval from onset to surgery, and time before complete CNP recovery. Pathological diagnoses comprised 17 pituitary adenomas, including 10 pituitary apoplexies and 4 adrenocorticotropic hormone-positive adenomas, and 13 other tumors, including 3 chordomas, 2 xanthogranulomas, 2 malignant lymphomas, 2 metastatic tumors, 1 Rathke cleft cyst, 1 plasmacytoma, 1 craniopharyngioma, and 1 neuroendocrine carcinoma. The mechanisms causing CNP were pituitary apoplexy (n= 10), cranial nerve compression or involvement (n= 17), and inflammatory changes (n= 9). As the first manifestation, 20 (66.7%) patients presented with oculomotor nerve palsy, 2 (6.7%) with trochlear nerve palsy, and 13 (43.3%) with abducens nerve palsy. Full recovery of CNP was obtained in 25 patients (83.3%) after surgery alone and in 2 patients (6.7%) after adjuvant therapy. Early surgery provided no significant difference in full recovery rates although it reduced the time to reach full recovery. It is critical to determine the mechanisms of CNP and intervene surgically to improve symptoms, shorten the duration of the disorder, prevent relapses, and obtain the correct pathological diagnosis to select the proper adjuvant therapy.

COVID-19 and sudden-onset ocular neurogenic palsy in prior healthy patients: a systematic review

ABSTRACT Background The aim of this systematic review is to identify cases of neurogenic ocular palsy in the presence of COVID-19 and to document patient characteristics, type of palsy and possible aetiologies. Methods A systematic search of PubMed, Medline and CINAHL databases was conducted on the 6th of January 2023 to identify cases of neurogenic ocular palsy in patients with current or previous COVID-19 infection. Data were pooled to summarise the neurogenic palsy, patient clinical characteristics and proposed palsy mechanisms. Results The combined database search yielded 1197 articles. Of these, 23 publications consisting of 25 patients met the inclusion criteria. Most patients were male (68%) and ranged in age from 2 to 71 years (median=32.7, SD=21.4). Seven patients (28%) were children aged 2 to 10 years old. Abducens palsies were most common (68%) and the most common ocular presentation was diplopia (76%) with an average time of onset 15 days from testing positive to COVID-19 or having symptoms of the virus. Proposed mechanism of development of a neurogenic palsy secondary to COVID-19 infection was classified into one of three categories: vascular/thrombotic, a viral neuro-invasive or inflammatory virus-mediated immune response. Discussion This study suggests that COVID-19 infection may be linked to oculomotor, trochlear and abducens nerve palsies and the underlying mechanisms may vary but are difficult to definitively establish. Further studies investigating the onset of neurogenic palsy secondary to COVID-19 infection is required.

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

To evaluate the effect of inferior oblique (IO) myectomy on ocular torsion according to the absence of the trochlear nerve in unilateral congenital superior oblique palsy (UCSOP). We retrospectively reviewed the clinical data of patients who had been diagnosed with UCSOP and underwent ipsilateral IO myectomy (n = 43). Patients were classified into the present and absent groups according to the absence of the trochlear nerve and superior oblique hypoplasia on magnetic resonance imaging (MRI). For quantitative analysis of ocular torsion, disc-fovea angles (DFA) were collected in both eyes using fundus photographs taken within three months before surgery and one month after surgery. DFA of the paretic eye did not differ according to the absence of the trochlear nerve (9.4±5.6° in the present group vs. 11.0±5.4° in the absent group, p = 0.508). However, the present group had a larger DFA in the non-paretic eye than the absent group (14.1±6.7° in the present group vs. 8.0±5.0° in the absent group, p = 0.003). The change of ocular torsion after IO myectomy in the paretic eye was -5.3±3.7° in the present group and -4.8±3.5° in the absent group, respectively (p = 0.801). In the non-paretic eye, the change in DFA was -1.5±3.0° in the present group, which was larger than that in the absent group (0.7±2.6°, p = 0.047). In the multivariate analysis, the change in DFA was correlated with only the preoperative DFA (standardized β = -0.617, p<0.001 in the paretic eye, and standardized β = -0.517, p<0.001 in the non-paretic eye). In the paretic eye, there was no significant difference in the change of ocular torsion between both groups, whereas in the non-paretic eye, the present group had a larger change in DFA after IO myectomy than the absent group. However, in the multivariable analysis, the change in ocular torsion was significantly correlated with preoperative excyclotorsion but not with the presence of the trochlear nerve itself.

Abstract Number ‐ 70: Combined Trans‐arterial Flow Diversion and Trans‐venous Embolization Management of High‐Flow Traumatic Cavernous‐Carotid Fistula (CCF)

Introduction Carotid‐Cavernous fistulas (CCF) are abnormal vascular shunts between the internal carotid artery (ICA) and the cavernous sinus. Most commonly due to trauma (75%), CCF occurs in 4%(1) of skull‐base fracture patients. Visual impairment, diplopia, and headache are typical presenting symptoms (88%). Proptosis, chemosis, ophthalmoparesis, and orbital bruits are notable exam findings. Cerebral angiography is the gold standard for diagnosis, showing cavernous sinus enlargement and ophthalmic vein or leptomeningeal vessel dilatation. CCF is typically treated endovascularly andballoon embolization has achieved cure rates of 88–99%(2). Successful obliteration using stents, however, has been reported(3, 4). While both trans‐arterial and the trans‐venous approach embolization are feasible depending on local vascular anatomy and accessibility of fistula points, the combination of trans‐arterial and trans‐venous approach is rarely employed.We present a case of traumatic, high‐flow CCF treated with combined trans‐arterial and trans‐venous coiling embolization and telescoped flow‐diverting stents. Methods A case report of successful treatment of traumatic high‐flow CCF with a combined trans‐arterial and trans‐venous coiling embolization with telescoped flow‐diverting stents. Results A 26‐year‐old woman presented with right eye proptosis, periorbital ecchymosis, and chemosistwo weeks after severe closed head injury treated with decompressive hemicraniectomy and subdural hematoma evacuation. Examination was notable for right eye blindness without light perception and right‐sided third, fourth, and sixth cranial nerve palsies and elevated intraocular pressure. CT head showed a skull base fracture involving the right carotid canal and angiography of ICA confirmed a high‐flow multi‐channel right CCF with diminished intracranial arterial flow and engorged bilateral ophthalmic veins. After unsuccessful attempts to catheterize the fistula via arterial approach, superior‐segment coil embolization was performed using an inferior petrosal venous approach; but further embolization of the cavernous sinus was unsuccessful. Using the cavernous‐petrous segment of the right ICA, a flow‐diversion stent was placed that significantly decreased cross‐fistula blood flow, improved intracranial arterial flow, and reduced bilateral ophthalmic vein congestion. After two months, intraocular pressure normalized and right eye vision returned, though moderate exophthalmos persisted. Angiography showed decreased but persistent residual CCF flow. Another flow‐diversion stent was successfully placed via trans‐arterial approach, covering the previous pipeline stent through petrous‐to‐ophthalmic right ICA. Three‐month follow‐up angiogram showed closure of the CCF with complete restoration of right eye vision. She ultimately underwent right cranioplasty and was able to return to work. Conclusions A combined trans‐venous coiling embolization and trans‐arterial flow‐diversion stenting may be effectively employed in the treatment of CCF with reversal of clinical symptoms and restoration of visual loss. Larger studies are needed to explore the role of this combined approach in the management of CCF.