Papers by M. Yashar S. Kalani
Neurosurgery, 2015
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World Neurosurgery, 2012
Given the genetic and proteomic advances of the past decade, understanding of the molecular etiop... more Given the genetic and proteomic advances of the past decade, understanding of the molecular etiopathogenesis of several complex diseases is increasing. Intervertebral disc disease (IVDD) is no different from other complex diseases where both environmental and genetic constituents are considered causes. This concept has challenged the traditional view that age, occupation, smoking, obesity, and primarily wear and tear are the only sources of disc degeneration. We conducted a systematic Medline review of the most current articles related to gene involvement in the development of IVDD in humans. Candidate gene linkage and association studies involving the functional components of the intervertebral disc, including collagen I, collagen IX, collagen XI, aggrecan, extracellular matrix-degrading enzymes, inflammatory cytokines (IL-1, IL-6, and TNFα), Fas/FasL and vitamin D receptors, have had promising results. This review emphasizes the latest advances in gene association with specific degenerated disc phenotypes, single nucleotide polymorphisms, disease heredity, and gene-environmental interactions in relation to IVDD to help improve future studies related to the genetic mechanisms underlying IVDD.
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Pediatric spinal arteriovenous malformations (AVMs) are rare and complex lesions to treat. There ... more Pediatric spinal arteriovenous malformations (AVMs) are rare and complex lesions to treat. There are few reports of the endovascular and microsurgical treatment of these lesions in the pediatric population, and the treatment outcomes of these patients are not well described. The aim of this study was the clinical and radiographic outcomes of spinal AVMs in pediatric patients treated via endovascular and microsurgical modalities. We identified nine children (5 boys, 4 girls; average age 11 years, range 3-17 years) treated for spinal AVMs between 1998 and 2010. Their charts were reviewed. Spinal AVMs most frequently involved the thoracic spinal cord. Four patients had associated Klippel-Trènaunay-Weber syndrome and one had hereditary hemorrhagic telangiectasia. There were two intramedullary, four conus medullaris, and three mixed extradural-intradural lesions. The most common presenting signs and symptoms were subarachnoid hemorrhage (n = 3) and paraparesis (n = 5). Endovascular intervention was used exclusively in two patients, and combined endovascular and microsurgical intervention was used in four patients. Surgery was the sole treatment in three patients with excellent results. There were two treatment-related complications: one case of subarachnoid hemorrhage and one case of scrotal swelling. The mean follow-up was 28.5 months and the median was 8 months (range, 1-65 months). The mean pretreatment World Health Organization (WHO)/Zubrod score was 2.4 (range, 1-4), and the mean post-treatment score was 1.4 (range, 0-4). One patient (11%) had a recurrence. Pediatric spinal AVMs require complex combined microsurgical and endovascular techniques to achieve favorable outcomes.
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Neurosurgery, 2013
The association of carotid body paragangliomas with neurovascular structures can cause cranial ne... more The association of carotid body paragangliomas with neurovascular structures can cause cranial nerve injury and significant intraoperative blood loss. Preoperative embolization may be performed either percutaneously or transarterially. We reviewed our experience with transfemoral transarterial Onyx embolization. We retrospectively reviewed a prospectively maintained database of head and neck tumors embolized between November 2007 and February 2012. Patients were assessed for number of sessions of embolization, number of pedicles embolized, fluoroscopic time, extent of tumor devascularization as assessed by postembolization angiography, and operative blood loss. Eleven patients (5 men, 6 women; mean age, 48.1 years) with 13 paragangliomas (5 right-sided, 9 left-sided, 2 bilateral) underwent preoperative embolization for 12 tumors. Onyx alone was used in 9 cases. In a mean of 1.2 embolization sessions (range, 1-2), an average of 2.8 pedicles (range, 1-7) was embolized. The average fluoroscopic time was 54.3 minutes. In 5 cases, the tumors were completely devascularized by using this strategy. In 5 cases, more than 90% tumor devascularization was achieved. In the remaining 2 cases, tumor devascularization was more than 50%. A partial cranial nerve XII palsy was the only postprocedural complication. The mean surgical blood loss was 191.7 mL (range, 25-600 mL). The arterial supply to carotid body tumors can be catheterized effectively through a transfemoral approach, permitting embolization of feeding pedicles. Transarterial Onyx embolization of these lesions is safe and effective, and it decreases blood loss during surgical resection.
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Neurosurgical FOCUS, 2011
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Journal of Neurosurgery: Spine, 2011
Coccidioides immitis is a dimorphous fungus endemic in the southwestern US and northern Mexico. W... more Coccidioides immitis is a dimorphous fungus endemic in the southwestern US and northern Mexico. While its primary presentation is pulmonary, it can have devastating neurological sequelae. The authors provide a retrospective review with long-term follow-up between 1986 and 2008 at a single institution. The authors identified 27 patients between 13 and 81 years old (mean 41.4 years) with spinal coccidioides who were treated surgically at the Barrow Neurological Institute between 1986 and 2008. There were 24 males (89%) and 3 females (11%). Eleven patients (41%) had cervical spine involvement, 15 (56%) had thoracic involvement, 7 (26%) had lumbar involvement, and 2 (7%) had sacral involvement. All 27 patients presented with localized or radiating pain. Nine patients (33%) had myelopathic symptoms at presentation, 5 (19%) had radiculopathy, 4 (15%) had fever, and 12 (44%) had progressive kyphosis. The disease was most frequently seen among African American patients (14 patients [52%]), followed by Caucasians (5 patients [19%]), Asians (3 patients [11%]), and Hispanics (3 patients [11%]). Ten patients (37%) required multiple operations at the same level. Follow-up was available in 19 patients (70%) (mean 9.8 months, range 1-39 months). Sixteen (84%) of these 19 patients improved from their preoperative baseline states, 1 (5%) was stable on examination, 1 patient's condition (5%) deteriorated compared with the preoperative examination, and 1 patient (5%) died in the postoperative period. Although spinal involvement of coccidioidomycosis is relatively uncommon, a high index of suspicion and aggressive therapy are warranted to prevent devastating neurological injury, and lifelong antifungal therapy is often warranted.
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Journal of Neurosurgery, 2012
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Journal of Clinical Neuroscience, 2013
Low-pressure hydrocephalus is a rare type of hydrocephalus characterized by negative intracranial... more Low-pressure hydrocephalus is a rare type of hydrocephalus characterized by negative intracranial pressure (ICP) and ventriculomegaly. Given the shortcomings of available methods to treat refractory low-pressure hydrocephalus, we set out to develop a new system for evacuation of cerebrospinal fluid (CSF) from the ventricular system where existing shunt systems do not produce the necessary gradient for CSF drainage. We retrospectively reviewed the charts of two patients with the diagnosis of negative-pressure hydrocephalus refractory to traditional treatments. We combined a traditional low-pressure, non-siphoning valve with a pumping chamber placed distal to the valve to create a system that could be actively pumped to remove excess CSF. Treatment of negative-pressure hydrocephalus requires the establishment of a lower ventricular drainage pressure than the drainage pressure in the subarachnoid space. In refractory cases, we propose the use of this active negative-pressure pumping system.
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Journal of neurosurgery. Spine, 2012
Cavernous malformations (CMs) are found throughout the CNS but are relatively uncommon in the spi... more Cavernous malformations (CMs) are found throughout the CNS but are relatively uncommon in the spine. In this report, the authors describe a giant CM with the imaging appearance of an aggressive, invasive, expansive tumor in the cervical spine. The intradural extramedullary portion of the tumor originated from a cervical nerve root; histologically, the lesion was identified as an intraneural CM. Most of the tumor extended into the paraspinal tissues. The tumor was also epidural, intraosseous, and osteolytic and had completely encased cervical nerve roots, peripheral nerves, branches of the brachial plexus, and the vertebral artery on the right side. It became symptomatic during the puerperal period. Gross-total resection was achieved using staged operative procedures, complex dural reconstruction, spinal fixation, and fusion. Clinical, radiographic, and histological details, as well as a discussion of the relevant literature, are provided.
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Child's Nervous System, 2011
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Neurosurgical FOCUS, 2008
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Papers by M. Yashar S. Kalani