Publications by authors named "Benzel E"

Object: The authors conducted a study to assess the anatomical appropriateness of using the S-2 dorsal neuroforamina as a hook fixation point, and they present the results of their clinical experience of using a nonscrew alternative for the surgical management of low lumbar (L-4 or L-5) burst fractures.

Methods: The technique used involves lumbar laminar fixation, rod contouring (to preserve lordosis), S- sublaminar wire fixation, S-2 dorsal neuroforaminal hook fixation, cross-fixation, and distraction. Because the S-2 dorsal neuroforamina was used as a unique fixation point, anatomical data obtained in 10 cadavers supporting the technique's utility are provided.

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Rheumatoid arthritis is associated with several pathologic changes in the cervical spine, including loss of articular cartilage, ligamentous destruction, and bone erosion. These changes may lead to one or a combination of complications, including atlantoaxial subluxation, cranial settling, subaxial cervical subluxation, and periodontoid pannus formation. Surgical management of these problems should focus on relieving pain, stabilizing the spine, and decompressing neural elements.

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Object: The availability of large-array biomagnetometers has led to advances in magnetoencephalography that permit scientists and clinicians to map selected brain functions onto magnetic resonance images. This merging of technologies is termed magnetic source (MS) imaging. The present study was undertaken to assess the role of MS imaging for the guidance of presurgical planning and intraoperative neurosurgical technique used in patients with intracranial mass lesions.

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Object: To demonstrate the safety and utility of one surgical approach, the authors reviewed their experience with the ventral surgical approach for decompression, reduction, and stabilization in 10 patients with either unilateral or bilateral cervical facet dislocation.

Methods: Six patients presented with unilateral cervical facet dislocation and four patients with bilateral cervical facet dislocation. There were six male and four female patients who ranged in age from 17 to 72 years (average 37.

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Neurotoxic intrathecal chemotherapy for childhood acute lymphoblastic leukemia (ALL) affects developing structures and functions of memory and learning subsystems selectively. Results show significant reductions in magnetic resonance imaging morphometry of mamillary bodies, components of the corticolimbic-diencephalic subsystem subserving functionally later developing, single-trial memory, nonsignificant changes in bilateral heads of the caudate nuclei, components of the corticostriatal subsystem subserving functionally earlier developing, multitrial learning, significant reductions in prefrontal cortical volume, visual and verbal single-trial memory deficits, and visuospatial, but not verbal, multitrial learning deficits. Multiple regression models provide evidence for partial dissociation and connectivity between the subsystems, and suggest that greater involvement of caudate may compensate for inefficient corticolimbic-diencephalic components.

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Object: Confirmation of cervical spine stability is difficult to obtain in the comatose or obtunded trauma patient. Concurrent therapies such as endotracheal intubation and the application of rigid cervical collars diminish the utility of plain radiographs. Bony as well as supportive soft-tissue structures must be evaluated before the cervical spine can be determined to be uninjured.

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Study Design: A multicenter, retrospective study using computed tomographic and magnetic resonance imaging data to establish quantitative, reliable criteria of canal compromise and cord compression in patients with cervical spinal cord injury.

Objectives: To develop and validate a radiologic assessment tool of spinal canal compromise and cord compression in cervical spinal cord injury for use in clinical trials.

Summary Of Background Data: There are few quantitative, reliable criteria for radiologic measurement of cervical spinal canal compromise or cord compression after acute spinal cord injury.

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Background: Following brain insult in early childhood, the later maturing neocerebellum and frontal lobes frequently show abnormalities.

Objective: To investigate the morphologic characteristics and function of a proposed cerebellar-frontal subsystem in children treated for acute lymphoblastic leukemia (ALL) with intrathecal methotrexate using quantitative magnetic resonance imaging, neuropsychological measures, nonlinear multiple regression analysis, and a statistical effect size model that augments interpretive validity of nonsignificant statistical findings, particularly from small sample size studies.

Design: Comparison and relationship of magnetic resonance imaging morphometry of cerebellar lobuli I-V and VI-VII and prefrontal cortices, and performance on 5 neuropsychological tests assessing visual-spatial attention, short-term memory, and visuomotor organization and coordination between childhood survivors of ALL and a matched control group.

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Background: The lateral extracavitary approach (LECA) to the thoracic and thoracolumbar spine allows ventral decompression and dorsal fixation of the spine through the same incision during a single procedure. The approach, however, is technically demanding and time-consuming. We sought to determine the incidence of complications associated with the LECA in patients with acute thoracolumbar spine injuries.

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Study Design: Retrospective review of the clinical course and cervical spine plain radiographs, computed tomography, and magnetic resonance imaging of 24 consecutive patients for a 2-year period with a unilateral lateral mass/facet fracture.

Objective: To propose a treatment algorithm for the management of unilateral lateral mass/facet fractures of the subaxial cervical spine based on ligamentous injury detected by magnetic resonance imaging.

Summary Of Background Data: There have been no previous reports of the use of magnetic resonance imaging to predict clinical instability.

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The thoracolumbar spine is the principal load-bearing structure of the body. As such, it is subject to a wide variety of forces that can be described by biomechanical principles. Forces act through vectors, depending on the direction of force and the relative location of the instantaneous axis of rotation.

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The metabolic response to trauma, including neurotrauma in general, has been studied extensively, but the acute metabolic response to spinal cord injury (SCI) has not. Therefore, 12 patients with SCI are presented in whom intensive nutrition assessment and management were instituted immediately after injury. Nitrogen balance (NB), predicted energy expenditure (PEE), and actual energy expenditure (MEE) were calculated or measured in each patient.

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Forty-four patients with cervical spondylotic myelopathy who underwent a ventral surgical approach were evaluated with respect to the results of surgery. The neurological status of the patients was categorized according to the modified Japanese Orthopedic Association scale (0-18). Three patients had a functional score of 8, one patient 9, five patients 10, five patients 11, seven patients 12, seven patients 13, seven patients 14, and nine patients had a functional score of 15, preoperatively.

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Cervical spondylotic myelopathy can produce a variety of clinical signs and symptoms secondary to neural compromise and biomechanical involvement of the spine. The surgical treatment of cervical spondylotic myelopathy remains a controversial issue after many years of study, evolution, and refinement. Several ventral, dorsal, or combined approaches have been defined.

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Because it is often difficult to diagnose accurately the structurally intact cervical spine after acute trauma, a series of patients was evaluated with magnetic resonance (MR) imaging to assess its efficacy for the evaluation and clearance of the cervical spine in a trauma victim in the early posttrauma period. Ultralow-field MR imaging was used to evaluate 174 posttraumatic patients in whom physical findings indicated the potential for spine injury or minor radiographic findings indicated injury. This series includes only those patients who did not appear to harbor disruption of spinal integrity on the basis of a routine x-ray film.

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Objective: The interface between a surgical needle and forceps affects needle-forceps stability. Stability has become more important with the introduction of blunt-point surgical needles. The stability at the needle-forceps interface can be assessed by quantitating resistance to both rotation and twisting.

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Background: Previous studies have suggested that diagnostic laparoscopy may be contraindicated in multiple trauma patients with closed head injuries because of the detrimental effects of carbon dioxide (CO2) pneumoperitoneum on intracranial pressure (ICP). In this study we compared the effects of two alternative inflation gases, helium (He) and nitrous oxide (N2O), against the standard agent used in most hospitals, CO2. ICP was monitored in experimental animals both with and without a space occupying intracranial lesion designed to simulate a closed head injury.

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We present an unusual radiographic manifestation of subclavian steal seen in six patients. These cases differ from the classic form of subclavian steal in that antegrade and bidirectional blood flow in the vertebral-subclavian artery system is seen, resulting in the steal phenomenon.

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Holographic technology has recently been modified in such a manner that it may now provide clinical use. It allows the visualization of complex structures in three dimensions and permits clinician interaction with the image, which, in turn, provides significant additional geometric and anatomic information. To objectively assess the potential clinical applicability of holography in pedicle screw placement, we studied 11 elderly human cadavers.

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