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

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

Differential Diagnoses for Isolated Right Sixth Nerve Palsy in the High Altitude Setting: A Case Report.

This case report describes the presentation and management of a patient with an isolated right sixth nerve palsy while trekking in Nepal. Consideration is made of the anatomy of the sixth nerve and the differential diagnoses afforded to this isolated sign, including high altitude cerebral edema. The case stresses the need to exclude life-threatening pathologies for any symptoms associated with altitude and includes decision-making processes on whether to monitor the patient in the field or evacuate them to a definitive care facility.

A Rare Case of Abducens Nerve Palsy Caused by Primary Squamous Cell Carcinoma of the Middle Ear.

Abducens nerve palsy is the most common ocular motor nerve palsy, and its possible aetiologies are numerous and diverse. Primary malignancy rarely occurs in the middle ear, with most cases associated with long-standing ear discharge and peak age of presentation in the sixties. We report a rare case of a 64-year-old male who presented with right abducens nerve palsy, which led to the diagnosis of primary squamous cell carcinoma of the right middle ear, and to our knowledge, this has not been reported previously in English literature.

Etiologic distribution of isolated abducens nerve palsy: Analysis of 807 patients and literature review.

BACKGROUND AND PURPOSE: The etiologies of abducens nerve palsy have shown a large variability among studies. This study aimed to establish the clinical features and underlying etiologies of isolated abducens nerve palsy by recruiting patients from all departments in a referral-based university hospital. METHODS: We reviewed the medical records of 807 patients with a confirmed diagnosis of isolated abducens nerve palsy at all departments of Seoul National University Bundang Hospital, Seongnam, Republic of Korea, from 2003 to 2020. We also compared the proportion of etiology with that of the patients pooled from the previous studies. RESULTS: The most common etiology was microvascular (n = 296, 36.7%), followed by idiopathic (n = 143, 17.7%), neoplastic (n = 115, 14.3%), vascular anomalies (n = 82, 10.2%), inflammatory (n = 76, 9.4%), and traumatic (n = 35, 4.3%). Patients were mostly managed by ophthalmologists (n = 576, 71.4%), followed by neurologists (n = 479, 59.4%), emergency physicians (n = 278, 34.4%), neurosurgeons (n = 191, 23.7%), and others (n = 72, 8.9%). The proportion of etiology significantly differed according to the age and sex of the patients and the specialties involved in the management (p < 0.001). Compared to the pooled data from the previous reports, the current study showed a higher prevalence of microvascular cause but a lower occurrence of traumatic and neoplastic causes. CONCLUSIONS: The results of previous studies on etiologic distribution of isolated abducens nerve palsy should be interpreted with consideration of the demographic features of patients recruited and the specialties involved.

Bilateral sixth nerve palsy with subdural hematoma: a unique presentation of B12 deficiency.

Vitamin B12 is inextricably associated with the development and maintenance of neuronal functions. It is classically associated with subacute combined degeneration and peripheral neuropathy; however, cranial neuropathy is uncommon. We observed the rarest neurological manifestation of B12 deficiency. A 12 months infant had history of lethargy, irritability, anorexia, paleness, vomiting, and neurodevelopmental delay for 2 months. He also developed inattention and altered sleep pattern. His mother noticed bilateral inward rotation of both eyes. On examination, the infant had bilateral lateral rectus palsy. The infant was found to have anemia (7.7g/dL) and severe B12 deficiency (74pg/mL). On MRI, there was cerebral atrophy, subdural hematoma (SDH) and wide cisternal spaces and sulci. On supplementation with cobalamin, he improved clinically though mild restriction of lateral gaze on the left side persists. Follow up MRI showed significant improvement in cerebral atrophy with resolution of SDH. To date, such clinical presentation of B12 deficiency has never been reported. The authors suggest B12 supplementation for at risk population esp at antenatal stage and lactating mothers in national programs. The treatment of this condition should be initiated early to prevent long term sequelae.

Vertebrobasilar dolichoectasia and other arterial abnormalities leading to abducens nerve palsy.

INTRODUCTION: Dolichoectatic vessels can cause cranial nerve dysfunction by either direct compression or ischemia. Abducens nerve palsy due to neurovascular compression by elongated, enlarged, tortuous or dilated arteries is an uncommon but important cause. AIM: To highlight neurovascular compression as a cause of abducens nerve palsy and discuss various diagnostic techniques. METHODS: Manuscripts were identified using the National Institutes of Health PubMed literature search system. Search terms included abducens nerve palsy, neurovascular compression, dolichoectasia and arterial compression. Inclusion criteria required that the articles were written in English. RESULTS: The literature search identified 21 case reports where abducens nerve palsy was due to vascular compression. Out of these 18 patients were male and the mean age was 54 years. Eight patients had unilateral right abducens nerve involvement; eleven patients had unilateral left nerve involvement and two patients had bilateral involvement. The arteries causing the compression were basilar, vertebral and anterior inferior cerebellar arteries. A compressed abducens nerve is not usually clearly detected on CT (Computed Tomography) or MRI (Magnetic Resonance Imaging). MRA (Magnetic Resonance Angiography), Heavy T2- WI (weighted imaging), CISS (constructive interference in steady state) and FIESTA (Fast Imaging Employing Steady-state Acquisition) are essential to demonstrate vascular compression of the abducens nerve. The various treatment options included controlling hypertension, glasses with prisms, muscle resection and microvascular decompression.

An atypical anatomical variation of the petrosphenoidal ligament in a newborn cadaver.

PURPOSE: To report an atypical anatomical variation of the petrosphenoidal ligament in a newborn cadaver and to discuss its clinical significance. METHODS: During a study of ten newborn cadavers, the skull base was dissected to reveal the anatomy of the petrosphenoidal ligament and its relationship with the abducens nerve. An atypical anatomical variation was observed, and this is described. The length of the right and left ligaments to the point where it splits into two arms, the joint length of the two ligaments at the junction of the clivus, the length of the ligament proceeding to the posterior clinoid process, and the abducens nerve's diameter as it passes below the ligament were measured on ImageJ software. RESULTS: The petrosphenoidal ligaments were y-shaped, and the attachment of the proximal ligaments was bifid. In the midline above the clivus, some ligament bundles joined the contralateral petrosphenoidal ligament, whilst another group of bundles originated at the posterior clinoid process. At the entry to Dorello's canal, the abducens nerve had a diameter of 0.59 mm on the left and 0.65 mm on the right. The part of the ligaments converging on the clivus in the midline after dividing into two arms was 10.68 mm. CONCLUSIONS: We think that this case report will provide useful information for surgical procedures to the petroclival region, transnasal surgical approaches, and surgical interventions involving the carotid artery.

A Case of Mycoplasma Infection with an Atypical Presentation of Abducens Nerve Palsy, Erythema Multiforme and Polyarthritis without Respiratory Manifestations.

Mycoplasma pneumoniae is a self-propagating microorganism that commonly causes respiratory tract infections. It can also cause a variety of extrapulmonary symptoms with or independently of respiratory symptoms, such as skin lesions, arthralgia, myalgia, hemolysis, cardiac lesions, gastrointestinal symptoms, and central nervous system lesions, which are rare manifestations reported in approximately 0.1% of cases. In this study, we present a unique case of Mycoplasma-related abducens nerve palsy, polyarthritis, and erythema multiforme without respiratory disease. The patient was a 69-year-old woman who presented to our hospital with a skin rash, fever, arthralgia, and diplopia without respiratory symptoms. Brain magnetic resonance imaging showed optic neuritis on the right side, suggesting the diplopia was caused by right abducens nerve palsy. However, the etiologies of abducens nerve palsy were not revealed by the physical examination, blood biochemistry tests, or bacteriological examinations, including the cerebrospinal fluid examination obtained at admission. Mycoplasma infection was suspected from erythema multiforme revealed by a skin biopsy and polyarthralgia, and it was finally diagnosed according to elevated Mycoplasma particle agglutination (PA) antibodies in paired serum. Though minocycline did not improve her diplopia, the daily administration of 30 mg of prednisolone gradually improved her symptoms, and the Mycoplasma PA antibody titer, which was regularly measured in the clinical course, also decreased, suggesting a relationship between Mycoplasma infection and abducens nerve palsy. This is the first case of isolated abducens nerve palsy, which was reported as the only central neurological symptom in an adult patient with Mycoplasma infection. The mechanism or pathogenesis of CNS manifestations caused by Mycoplasma pneumoniae remains to be elucidated, and further investigation is needed. Hence, Mycoplasma infection is a common disease. Clinicians should be aware of the diverse manifestations, including abducens nerve palsy, of Mycoplasma infection and should consider Mycoplasma infection even in the absence of typical respiratory symptoms.

Simultaneous Unilateral Abducens Nerve Palsy and Contralateral Anterior Ischaemic Optic Neuropathy as the Presenting Signs of Giant Cell Arteritis.

Ischaemic optic neuropathy is the most common, feared, and recognised ocular manifestation of giant cell arteritis (GCA), while extraocular muscle palsy rarely occurs in the disease. Overlooking the diagnosis of GCA in aged patients with acquired diplopia and strabismus is not only sight- but also life-threatening. Here, we present, for the first time, a case of unilateral abducens nerve palsy and contralateral anterior ischaemic optic neuropathy as the presenting signs of GCA in a 98-year-old woman. Prompt diagnosis and treatment prevented further visual loss and systemic complications and allowed for rapid resolution of the abducens nerve palsy. We also aim to discuss the possible pathophysiological mechanisms of diplopia in GCA and to emphasise that acquired cranial nerve palsy must raise suspicion of this severe disease in elderly patients, particularly in association with ischaemic optic neuropathy.

Persistent Trigeminal Artery Causing an Abducens Nerve Palsy: A Case Report.

We present a case of a 50-year-old female who was diagnosed with an isolated right abducens nerve palsy and was found to have a persistent trigeminal artery (PTA). The trigeminal artery is the most common persistent embryological carotid-vertebrobasilar anastomosis. A PTA can be picked up as an incidental finding on magnetic resonance imaging (MRI) or angiography. It has been reported that a PTA can be found in 0.1 to 0.6% of all cerebral angiograms. PTA has been linked to several rare abnormalities such as vascular aneurysms and cranial nerve compression. Our patient presented with diplopia and was found to have a paresis of the right lateral rectus muscle consistent with a right abducens nerve palsy. MRI found a right-sided PTA indenting the ventral surface of the pons. This case investigates and highlights that neurovascular compression from a PTA can cause an isolated abducens nerve palsy. Further research is required to investigate if surgical intervention for non-aneurysmal PTA would be beneficial for patients.

Traumatic retroclival epidural hematoma associated with reversible ipsilateral internal carotid artery stenosis.

INTRODUCTION: Traumatic retroclival epidural hematoma is rare. It is more common in pediatrics than in adults. Although it has been known that these cases are frequently associated with abducens nerve palsy, internal carotid artery stenosis is rarely found with those hematomas. CASE REPORT: An 8-year-old girl was transferred to our hospital following a traffic accident. She had clear consciousness with right abducens nerve palsy. Computed tomography revealed the left side of both retroclival hematoma without clival fracture and subarachnoid hemorrhage at the Sylvian fissure. She also had a fracture of left femoral neck and ipsilateral lung contusion. Magnetic resonance imaging revealed a retroclival hematoma located in the epidural space and severe stenosis of left internal carotid artery (ICA) from the cavernous to supraclinoid portion without evidence of brain contusion. She was managed conservatively, and her right abducens nerve palsy recovered completely without deterioration of other neurological findings. Neuroradiological findings suggested this ICA stenosis as traumatic dissection. She was discharged home 2 months after the traffic accident. CONCLUSION: Retroclival epidural hematoma without clival fracture associated with ipsilateral ICA stenosis is extremely rare. Although the exact mechanism of the ICA stenosis remains unclear, cerebral vascular events should be considered in the cases with traumatic retroclival hematoma.

Initial Presentation of Granulomatosis with Polyangiitis as Progressive Skull Base Osteomyelitis.

A healthy man in his 30s presented with a 2-week history of severe bitemporal pain and pressure. He was initially treated for presumed acute rhinosinusitis, but his symptoms continued to worsen and underwent endoscopic sinus surgery at an outside community facility. He developed left abducens nerve palsy postoperatively, and magnetic resonance imaging (MRI) demonstrated evidence of extensive skull base osteomyelitis. He was initiated on intravenous (IV) broad-spectrum antibiotics but was subsequently found to have prostatic and submandibular sterile fluid collections. The patient subsequently developed new right abducens and left vagal nerve palsies and underwent revision endoscopic sinus surgery. Pathology revealed extensive inflammation, necrotizing granulomas, and evidence of small and medium vessel vasculitis. Extensive laboratory workup was negative, except for anti-PR-3 antibody positivity. Given the characteristic findings on pathology and laboratory findings, the patient was diagnosed with granulomatosis with polyangiitis (GPA). High-dose glucocorticoid therapy as well as rituximab infusion were promptly initiated. He had marked improvement in his symptoms and resolution of his right CN VI palsy but left-sided CN VI and CN X palsies persisted. This patient presented without the typical rhinologic manifestations of GPA, and rather presented with progressive sinusitis, skull base osteomyelitis with associated cranial neuropathies, and aseptic systemic abscesses. Prompt diagnosis of GPA is particularly important in those with otorhinolaryngological manifestations, as early initial immunosuppressive therapy has been linked to lower relapse and mortality rates. Vigilance and early differentiation between GPA and other forms of sinusitis is of critical importance, particularly when symptoms are refractory to standard rhinosinusitis therapies.

High resolution 3D magnetic resonance imaging of Gruber's ligament: a pilot study.

INTRODUCTION: Gruber's ligament (GL), a surgical landmark, extends from the lateral upper clivus to the petrous apex (PA), forming the superior boundary of Dorello's canal (DC). It overlies the interdural segment of the abducens nerve (CN VI). High-resolution 3D skull base MRI (SB-MRI) demonstrates anatomic details visible to the surgeon, but not well seen on traditional cross-sectional imaging. The aim of this study was to demonstrate visualization of the GL and its relationship to CN VI utilizing contrast enhanced high-resolution SB-MRI. METHODS: Two neuroradiologists retrospectively reviewed in consensus the SB-MRIs of 27 skull base sides, among 14 patients. GL detection rate, confidence of detection, and GL length were recorded. When GL was successfully identified, the position of the interdural segment of CN VI within DC was recorded. RESULTS: GL was readily identified in 16 skull base sides (59%), identified with some difficulty in 2 skull base sides (7%), and failed to be identified in 9 skull base sides (33%). The mean GL length was 7.1 mm (4.5-9.3 mm). Among the 18 cases where GL was successfully identified, CN VI was readily identified in all cases (100%), coursing the lateral third of DC in 72% of sides, and middle third in the remaining 28% of sides. CONCLUSION: GL can be identified in approximately two-thirds of cases utilizing 3D high resolution SB-MRI. CN VI passes most commonly along the lateral third of DC. This is the first report demonstrating visualization of GL and its relation to CN VI, on imaging.

Scrub Typhus Presenting as Unilateral Abducens Nerve Palsy.

Scrub typhus, an acute febrile infectious disease prevalent in the "Tsutsugamushi Triangle", is a mite-born rickettsial zoonosis, caused by Orientia tsutsugamushi. Although the clinical presentation is protean, it rarely causes abducens nerve palsy. We report a 14-year-old previously healthy Indian girl who presented with a recent onset right abducens nerve palsy and headache, but without fever and without the classic dermatological manifestation ("eschar") of the disease. After exclusion of common infectious, autoimmune, and neoplastic causes, she was finally diagnosed with scrub typhus associated with an abducens nerve palsy, which responded to doxycycline therapy.

Association of lateral rectus muscle volume and ocular motility with the abducens nerve in Duane's retraction syndrome.

PURPOSE: To investigate the relationship between ocular motility and lateral rectus (LR) muscle volume according to the presence or absence of the abducens nerve in patients with Duane's retraction syndrome (DRS) using high-resolution magnetic resonance imaging (MRI). METHODS: A total of 54 unilateral DRS patients were divided into two groups according to high-resolution MRI findings: DRS without an abducens nerve on the affected side (absent CN6 group, n = 45) and DRS with symmetric abducens nerves on both sides (present CN6 group, n = 9). Ocular motility was measured by image analysis based on nine gaze photographs. LR volume was measured on T2-weighted coronal MRI of the orbit, and the ratio of paretic/normal side (P/N) LR volume was investigated. Association of the abducens nerve with various parameters including ocular motility, LR volume, and ratios of P/N LR volume were determined. RESULTS: LR volume was smaller in the affected eye than the non-affected eye in both groups. In the present CN6 group, abducens nerve diameter and the ratio of P/N LR volume showed a positive correlation. A smaller LR volume and more limitation of abduction in the affected eye were predictive of an absent abducens nerve in DRS. CONCLUSIONS: LR muscle hypoplasia was apparent in the affected eye of DRS patients. Abducens nerve diameter positively correlated with the ratio of P/N LR volume in the present CN6 group. Graphical abstract.

Location of the abducens nerve stretched by a tortuous vertebrobasilar artery in trigeminal neuralgia.

BACKGROUND: Trigeminal neuralgia (TGN) caused by the vertebrobasilar artery (VBA) is uncommon. The abducens nerve root is frequently dislocated by a tortuous VBA near the trigeminal nerve root. This unusual location of the root is not well known. This study aimed to investigate the location of the stretched abducens nerve root. METHODS: The objective is 26 patients with VBA-related TGN who underwent microvascular decompression (MVD). We retrospectively investigated the course of the abducens nerve root with magnetic resonance imaging (MRI) with three-dimensional (3D) imaging and surgical findings. The displacement of the abducens nerve root on the affected side was compared to the contralateral side. RESULTS: The abducens nerve root was distorted by a tortuous VBA (46.2%) or the anterior inferior cerebellar artery (53.8%). The average length of the cisternal segment was stretched to 23.4 mm versus 12.4 mm on the contralateral side. The peak point of the elevated abducens nerve root was mostly located rostro-medial (65.4%) or caudo-medial (34.6%) to the neurovascular compression site of the trigeminal nerve with a mean distance of 9.1 mm. Contact with the trigeminal nerve root was observed in 7 patients (26.9%). Three-dimensional imaging was consistent with the surgical findings and useful in predicting the location of the abducens nerve root. No abducens nerve palsy was noted in our series. CONCLUSIONS: The abducens nerve root is located near the trigeminal nerve root in VBA-related TGN. Preoperative understanding of the unusual course of the abducens nerve root contributes to avoiding accidental nerve injury during MVD.

Effect of clival bone growth on the localization of the abducens nerve at the petroclival region: a postmortem anatomical study.

PURPOSE: To investigate the effect of the clival bone pattern on the abducens nerve (AN) localization in the petroclival region between the Pediatric and Adult Groups. METHODS: This study used 12 pediatric and 17 adult heads obtained from the autopsy. The length and width of the clivus and the length of the petrosphenoidal ligaments (PSLs) were measured. The ratio of the length and width of the clivus was accepted as the clival index (CI). The localization of the AN at the petroclival region below the PSL, classified as lateral and medial, were recorded. RESULTS: The average length of the clivus was 26.92 ± 2.88 mm in the Pediatric Group, and 40.66 ± 4.17 mm in the Adult Group (p < 0.001). The average width of the clivus was 22.35 ± 2.88 mm in the Pediatric Group, and 29.96 ± 3.86 mm in the Adult Group (p < 0.001). The average value of the CI was 1.20 in the Pediatric Group and 1.36 in the Adult Group (p = 0.003). The length of the PSL was 7.0 ± 1.47 mm in the Pediatric Group and 11.05 ± 2.95 mm in the Adult Group (p < 0.001). The nerve was located below the medial side of the PSL in the Pediatric Group and below the lateral side in the Adult Group (p = 0.002). CONCLUSIONS: The petrous apex localization of the AN in adults compared with pediatric subjects could be related to the increased growth in the length of the clivus than its width.

Intracranial intradural variations of nerve roots.

BACKGROUND: The aim of this paper was to point out the intradural cranial nerve roots variations in their localization and number to establish the incidence and clinical importance of the cranial nerve root variations. METHODS: The anatomical study was performed on 120 sides in 60 cadavers. There were 51 male cadavers with the mean age 43.3 and 9 female cadavers with the mean age of 39.5 years. RESULTS: Abducens nerve variations were observed in 48 cases (80 %). They were more frequently on the left side, in 25 cases (41.66 %). Duplicated abducens nerve was observed in 25 cases (41.66 %). Double and triple abducens nerve variations were also observed. CONCLUSIONS: Cranial nerve variations are rare, but variations of abducens nerve and atypical exit of the hypoglossal nerve from the fossa cranium posterior is not a rare variation. Knowledge of this variation may be important to various fields of medicine (Tab. 3, Fig. 8, Ref. 34).

Case report: Mononeuritis multiplex in the course of dengue fever.

BACKGROUND: Dengue fever usually presents as a self-limiting acute febrile illness with worsening thrombocytopenia, with a small minority of patients developing hemorrhagic or life-threatening complications. Organ specific manifestations like myocarditis, acalculous cholecystitis, encephalitis has been described but are uncommon presentations. Even more rarely, such manifestations are the presenting complaint of Dengue fever. In this case report, we highlight a case of Dengue fever where unrelated neuropathies were the presenting complaint. CASE PRESENTATION: An elderly man presents with 1 day of diplopia and left foot drop, associated with 2 days history of fever. A decreasing white cell count (WBC) and platelet on the 2nd day of admission prompted Dengue virus to be tested and a positive NS-1 antigen was detected, confirming the diagnosis of Dengue fever. He was treated with supportive treatment with a short duration of intravenous fluids recovered uneventfully and was discharged 6 days after admission with almost full resolution of diplopia and partial resolution of left foot drop. Left foot drop recovered completely 2 weeks later. CONCLUSION: Neurological manifestations can be the presenting symptoms in Dengue fever, a diagnosis which should be borne in mind when such symptoms present in patients from endemic areas or in returning travellers from these areas.

A clinical study of ocular motor nerve functions after petroclival meningioma resection.

BACKGROUND: Ocular motor dysfunction is one of the most common postoperative complications of petroclival meningioma. However, its incidence, recovery rate, and independent risk factors remain poorly explored. METHODS: A prospective analysis of 31 petroclival meningiomas was performed. Operative approaches were selected by utilizing a new 6-region classification of petroclival meningiomas we proposed. Two scores were used to evaluate the functions of the oculomotor and abducens nerves. Pearson correlation analysis and binary logistic regression analysis were used to identify independent risk factors for intraoperative oculomotor and abducens nerve injury. RESULTS: Postoperative new-onset dysfunctions in the pupillary light reflex and eye/eyelid movements as well as abducens paralysis were detected in eight (25.8%), ten (32.3%) and twelve (38.7%) cases, respectively. Their corresponding recovery rates after 6 months of follow-up were 75% (6/8), 80% (8/10), and 83.3% (10/12), respectively, and their mean times to start recovery were 4.03, 2.43, and 2.5 months, respectively. Tumor invasion into the suprasellar region/sphenoid sinus was the only risk factor for dysfunctions in both the pupillary light reflex (p = 0.001) and eye/eyelid movements (p = 0.002). Intraoperative utilization of the infratrigeminal interspace was the only risk factor for dysfunction in eyeball abduction movement (p = 0.004). CONCLUSIONS: Dysfunctions of the oculomotor and abducens nerves recovered within 6 months postoperatively. Tumor extension into the suprasellar region/sphenoid sinus was the only risk factor for oculomotor nerve paralysis. Eye/eyelid movements were more sensitive than the pupillary light reflex in reflecting nerve dysfunctions. Intraoperative utilization of the infratrigeminal interspace was the only risk factor for abducens nerve paralysis.