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Objective: Skull base chordomas (SBCs) often present with cranial nerve (CN) VI deficits. Studies have not assessed the prognosis and predictive factors for CN VI recovery among patients presenting with CN VI deficits., Methods: The medical records of patients who underwent resection for primary chordoma from 2001 to 2020 were reviewed. Those presenting with CN VI palsy were identified. The extent of CN VI deficit was determined to be partial or complete based on the Scott-Kraft score. The change in deficit from baseline was recorded within 3 days of surgery and at the 6-month follow-up. The postoperative course was followed until partial and/or complete deficit recovery. Univariate logistic regression models were created to predict improvement or resolution of CN VI deficit., Results: A total of 113 patients with primary SBC were identified, 34 of whom presented with CN VI deficits: 24 (73%) with partial and 9 (27%) with complete deficits. The extent of deficit in 1 patient was unable to be determined. The median duration of deficit preoperatively was 3.6 months, and CN VI was most commonly radiographically abutted at the prepontine cistern and Dorello's canal. Twenty-three (68%) patients experienced at least partial CN VI recovery (mean 61 days, range 2-174 days). Nineteen (56%) patients experienced complete CN VI recovery (mean 162 days, range 2-469 days). No patients whose CN VI deficit worsened immediately after surgery achieved improvement in CN VI function at 6 months (p = 0.001). Preoperative partial (relative to complete) CN VI deficit was associated with greater odds of CN VI deficit improvement by 6 months (OR 7.7, p = 0.028). Factors not associated with deficit resolution included duration of deficit, CN VI involvement by tumor, total segments abutted by tumor, sex, age at diagnosis, gross-total resection, tumor volume, and adjuvant radiation therapy, although this analysis may have been underpowered to detect small differences., Conclusions: Overall, 68% of patients achieved at least partial recovery in CN VI function after endoscopic skull base surgery. Among patients with partial CN VI palsy at baseline, 83% achieved CN VI recovery within 6 months and 75% achieved complete recovery within 14 months. For patients who presented with a complete CN VI deficit, within those same time frames, 33% and 11% achieved partial and complete recovery, respectively. Complete preoperative CN VI deficit was associated with lower odds of CN VI recovery by 6 months. The duration of preoperative deficit does not predict functional CN VI recovery.

An isolated cranial nerve VI palsy is a rare initial manifestation of undiagnosed neurosyphilis. A 33-year-old male presented with a one month history of progressive headache and diplopia. Neurologic examination only revealed an isolated abducens palsy on the left. Cranial imaging was unremarkable. Examination of his cerebrospinal fluid revealed lymphocytic predominant leukocytosis and elevated protein. Microbiologic work-up were all negative. Further work-up revealed the patient to be serum Rapid Plasma Reagin and Enzyme Immunoassay reactive. Enzyme-linked immunosorbent assay for Human Immunodeficiency Virus also tested positive. His cerebrospinal fluid was then sent for Rapid Plasma Reagin to confirm the diagnosis of neurosyphilis. He completed 14 days of intravenous penicillin and was eventually discharged with partial resolution of the abducens palsy. We describe the second case of neurosyphilis presenting only with an isolated cranial nerve VI involvement. On further review, ours was the first case documented on an individual who had an undiagnosed Human Immunodeficiency Virus infection. There are various differentials for an isolated cranial neuritis but infectious causes, particularly neurosyphilis, should be considered among young individuals with known risk factors despite their apparently benign medical history.

The clinical and radiological findings of a patient affected by apoplexy of an adenoma located within cavernous sinus and presenting isolated Cranial Nerve (CN) VI palsy are reported. The differential diagnosis with other pathologies is debated, and pathogenesis of isolated abducens nerve palsy is investigated. The pertinent literature of this uncommon case of apoplexy is reviewed. A 59-year-old female presented sudden appearance of CN VI palsy associated to violent headache. Endocrinological assessment did not show pituitary insufficiency; MRI depicted an adenoma located within the left CS. She underwent an endoscopic endonasal procedure with extensive opening of the cavernous sinus, occupied by an ischemic adenoma. Afterward, neurological symptoms promptly resolved and the patient was discharged after 5 days. At 3 months follow-up MRI radical tumor removal was assessed, and the patient resulted neurologically intact. The review of the pertinent literature shows that apoplexy of pituitary tumor exclusively located within the Cavernous Sinus is a very uncommon event. The distinctive clinical presentation is represented by the sudden abducens nerve palsy and the absence of pituitary insufficiency and it could be explained by the vulnerability of the nerve along its course within the cavernous sinus, and by the sparing of the sellar content by the adenoma. [ABSTRACT FROM AUTHOR]

Abstract: Nonpharmacologic and nonsurgical transcranial modulation of the nerve function may provide new opportunities in evaluation and treatment of cranial nerve diseases. This study investigates the possibility of using low-intensity transcranial focused ultrasound (FUS) to selectively stimulate the rat abducens nerve located above the base of the skull. FUS (frequencies of 350 kHz and 650 kHz) operating in a pulsed mode was applied to the abducens nerve of Sprague-Dawley rats under stereotactic guidance. The abductive eyeball movement ipsilateral to the side of sonication was observed at 350 kHz, using the 0.36-msec tone burst duration (TBD), 1.5-kHz pulse repetition frequency (PRF), and the overall sonication duration of 200 msec. Histologic and behavioral monitoring showed no signs of disruption in the blood brain barrier (BBB), as well as no damage to the nerves and adjacent brain tissue resulting from the sonication. As a novel functional neuro-modulatory modality, the pulsed application of FUS has potential for diagnostic and therapeutic applications in diseases of the peripheral nervous system. [Copyright &y& Elsevier]

Abstract: We report the case of a previously healthy 4 year-old African American female who presented to the emergency department with acute onset of unilateral abducens nerve palsy and torticollis. Within 12 h of presentation, the patient’s symptoms progressed to include ipsilateral facial nerve palsy and gait ataxia. On exam, the patient demonstrated right cranial nerve VI and VII palsies, ataxic gait with left lateropulsion, spasticity of bilateral lower extremities with clonus, and the presence of bilateral Babinski sign. MRI of the brain and spinal cord revealed severe Chiari I malformation with associated extensive holochord syringomyelia and syringobulbia. The patient underwent successful surgical decompression 72 h after initial presentation. We review the literature on Chiari malformations and syringomyelia, including epidemiology, presentation and neurological manifestations, and treatment recommendations. As our patient had a very acute presentation, we additionally review the previously reported cases of acute and atypical presentation of patients with Chiari I malformation and syringomyelia. The aim of this report is to make practitioners aware of the acuteness with which children with Chiari malformation type I with syringomyelia and syringobulbia can present. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]