Publications by authors named "Koby M"

Craniocervical instability (CCI) is increasingly recognized in hereditary disorders of connective tissue and in some patients following suboccipital decompression for Chiari malformation (CMI) or low-lying cerebellar tonsils (LLCT). CCI is characterized by severe headache and neck pain, cervical medullary syndrome, lower cranial nerve deficits, myelopathy, and radiological metrics, for which occipital cervical fusion (OCF) has been advocated. We conducted a retrospective analysis of patients with CCI and Ehlers-Danlos syndrome (EDS) to determine whether the surgical outcomes supported the criteria by which patients were selected for OCF.

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Article Synopsis
  • The study identifies a surprising link between atlantoaxial instability (AAI) and hereditary connective tissue disorders, noting that AAI is often associated with symptoms like syncope and lightheadedness.
  • It involved 20 subjects who underwent surgical procedures to stabilize the affected spine segments, with improvements reported in autonomic symptoms post-surgery.
  • The findings highlight the importance of recognizing AAI-related symptoms that may not respond to standard medical treatments, indicating surgery can significantly alleviate these issues.
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Atlanto-axial instability (AAI) is common in the connective tissue disorders, such as rheumatoid arthritis, and increasingly recognized in the heritable disorders of Stickler, Loeys-Dietz, Marfan, Morquio, and Ehlers-Danlos (EDS) syndromes, where it typically presents as a rotary subluxation due to incompetence of the alar ligament. This retrospective, IRB-approved study examines 20 subjects with Fielding type 1 rotary subluxation, characterized by anterior subluxation of the facet on one side, with a normal atlanto-dental interval. Subjects diagnosed with a heritable connective tissue disorder, and AAI had failed non-operative treatment and presented with severe headache, neck pain, and characteristic neurological findings.

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Proper craniocervical alignment during craniocervical reduction, stabilization, and fusion optimizes cerebrospinal fluid (CSF) flow through the foramen magnum, establishes the appropriate "gaze angle", avoids dysphagia and dyspnea, and, most importantly, normalizes the clival-axial angle (CXA) to reduce ventral brainstem compression. To illustrate the metrics of reduction that include CXA, posterior occipital cervical angle, orbital-axial or "gaze angle", and mandible-axial angle, we present a video illustration of a patient presenting with signs and symptoms of the cervical medullary syndrome along with concordant radiographic findings of craniocervical instability as identified on dynamic imaging and through assessment of the CXA, Harris, and Grabb-Oakes measurements.

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A great deal of literature has drawn attention to the "complex Chiari," wherein the presence of instability or ventral brainstem compression prompts consideration for addressing both concerns at the time of surgery. This report addresses the clinical and radiological features and surgical outcomes in a consecutive series of subjects with hereditary connective tissue disorders (HCTD) and Chiari malformation. In 2011 and 2012, 22 consecutive patients with cervical medullary syndrome and geneticist-confirmed hereditary connective tissue disorder (HCTD), with Chiari malformation (type 1 or 0) and kyphotic clivo-axial angle (CXA) enrolled in the IRB-approved study (IRB# 10-036-06: GBMC).

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There is growing recognition of the kyphotic clivo-axial angle (CXA) as an index of risk of brainstem deformity and craniocervical instability. This review of literature and prospective pilot study is the first to address the potential correlation between correction of the pathological CXA and postoperative clinical outcome. The CXA is a useful sentinel to alert the radiologist and surgeon to the possibility of brainstem deformity or instability.

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The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of heritable connective tissue disorders characterized by joint hypermobility, skin extensibility, and tissue fragility. This communication briefly reports upon the neurological manifestations that arise including the weakness of the ligaments of the craniocervical junction and spine, early disc degeneration, and the weakness of the epineurium and perineurium surrounding peripheral nerves. Entrapment, deformation, and biophysical deformative stresses exerted upon the nervous system may alter gene expression, neuronal function and phenotypic expression.

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An 83-year-old male presented with bilateral carotid stenosis. Stenosis on the left side was reported to be greater than 70%. A left carotid endarterectomy was undertaken to increase the lumen size and remove the atherosclerotic plaque.

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The authors compared hemisphere-based and cognitive-domain-based hypotheses for visual-spatial deficits in children with stroke (n = 33) and children without stroke (n = 43). Children with unilateral left (n = 14) or right (n = 7) injury showed less efficient search for the visual field contralateral to their injury. Right-hemisphere injury was associated with deficient global-level processing and coordinate spatial judgments.

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Anterior brain insults during development have been shown to result in visual orienting deficits; however, the type of orienting deficit has varied across studies. Performance on an orienting task was examined in relation to the location and volume of injury on magnetic resonance exams in 15 children with cerebral infarction and 32 control children. Contralateral lesions including the parietal lobe were associated with larger validity effects, suggesting difficulties disengaging attention.

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We describe two cases of pituitary involvement by Wegener's granulomatosis. At initial presentation, or during subsequent disease "flares," a pattern of pituitary abnormality was suggested. During periods of remission, we found the pituitary returned to a nearly normal appearance.

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Objective: In children with sickle cell disease (SCD), silent cerebral infarcts are the most frequent cause of neurologic injury. We determined the sensitivity and specificity of selective neurocognitive measures when separating children with silent cerebral infarcts and SCD from sibling controls. Additionally, we tested the validity of the same cognitive measures to identify patients with overt strokes.

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Associate learning for visual nonverbal and auditory verbal items was examined in 21 children with spastic diplegic cerebral palsy (SDCP) and 28 healthy children using four paired associate tasks. SDCP children showed poorer performance than the comparison group for learning pairs that required visual nonverbal responses, regardless of the stimulus modality. Within the SDCP group, lesion severity was assessed in 17 of the children.

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Hearing impairment was anecdotally reported in resistance to thyroid hormone (RTH), a condition caused by mutations in the beta-thyroid hormone receptor (beta TR) gene. Because of its ontogenic distribution in the cochlea, the beta TR may have a pivotal role in the development of auditory function. To assess the prevalence and mechanisms of hearing impairment in RTH, 82 RTH-positive (RTH+) patients and 55 unaffected relatives (RTH-) underwent systematic audiological examination, including puretone and speech reception thresholds, and tests studying middle ear (tympanometry and acoustic reflexes), cochlear (otoacoustic emissions), and retrocochlear integrity (brain stem auditory evoked potentials).

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Objective: Morphing is an image processing technology that transforms one image into another by generating a series of intermediate synthetic images. The ability to perform morphing, once restricted to high-end graphics workstations, is now widely available for desktop computers. We investigated the potential use of morphing for displaying radiographic images.

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Background: Intrasellar abscess following transsphenoidal surgery has been described only twice in the English language medical literature. Overall mortality associated with intrasellar abscesses is 51%, while mortality in reported cases not treated surgically is 100%.

Methods: Two cases of intrasellar abscess following uncomplicated transsphenoidal surgery for pituitary pathology are reported.

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Neurosurgical management of birth-related brachial plexus palsy involves observing the patient for a period of several months. Operative intervention is usually undertaken at 3 to 6 months of age or more in infants who have shown little or no improvement in affected muscle groups. Ancillary tests such as electromyography and nerve conduction studies are occasionally useful.

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Objective: Esthesioneuroblastomas are uncommon tumors originating in the olfactory epithelium of the superior nasal cavity. Accurate staging appropriately guides therapy and predicts survival. The MR appearance and pattern of contrast enhancement in these tumors have not been well described.

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We evaluated a topical formulation of timolol in an anionic heteropolysaccharide gellan gum (Gelrite). Fifty-five white patients with ocular hypertension entered a double-masked, placebo-controlled, four-period, incomplete block crossover study. After washout of any ocular hypotensive medications, the intraocular pressure of both eyes of all patients was measured at 0 (09:00 h), 2, 4, 6, 8, 12, and 24 h (diurnal baseline).

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