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Daniel K Resnick

Publications and source records attributed to Daniel K Resnick.

9 recordsLinked to original sources
PubMed2003

Adult olfactory ensheathing cell transplantation for acute spinal cord injury.

Cellular transplantation strategies have been explored for the treatment of spinal cord injury. In particular, olfactory nerve ensheathing cell (OEC) transplantation has been reported to improve functional outcome following injury. We investigated the effect of OEC transplantation using cells derived from adult animals on the restoration of function following a contusion injury to the spinal cord. The NYU impactor was used to create a moderate to severe spinal cord injury in 17 rats. Hoescht stained cultured OECs derived from adult rats (n = 7) or culture medium alone (n = 10) were injected into the injury site immediately following injury. Histological and functional outcomes were measured using immunohistochemistry and the Basso, Beattie, and Bresnahan (BBB) scale. All animals transplanted with OECs were found to have surviving Hoescht positive cells within the spinal cord when sacrificed 6 weeks following injury. Immunohistochemical staining of the explanted cords revealed that the surviving cells stained positively for nerve growth factor receptor. Functional outcomes were not different between the transplanted and control groups. OECs transplanted immediately following a contusion injury to the spinal cord survive during the first 6 weeks following injury. These cells do not appear to influence functional outcome during the first 6 weeks following injury. Additional studies are required in order to definitively determine the utility of this type of cellular transplantation for spinal cord injury.

Animals↗
PubMed2003

Prospective comparison of virtual fluoroscopy to fluoroscopy and plain radiographs for placement of lumbar pedicle screws.

Fluoroscopy-based frameless stereotactic systems provide feedback to the surgeon using virtual fluoroscopic images. The real-life accuracy of these virtual images has not been compared with traditional fluoroscopy in a clinical setting. We prospectively studied 23 consecutive cases. In two cases, registration errors precluded the use of virtual fluoroscopy. Pedicle probes placed with virtual fluoroscopic imaging were imaged with traditional fluoroscopy in the remaining 21 cases. Position of the probes was judged to be ideal, acceptable but not ideal, or not acceptable based on the traditional fluoroscopic images. Virtual fluoroscopy was used to place probes in for 97 pedicles from L1 to the sacrum. Eighty-eight probes were judged to be in ideal position, eight were judged to be acceptable but not ideal, and one probe was judged to be in an unacceptable position. This probe was angled toward an adjacent disc space. Therefore, 96 of 97 probes placed using virtual fluoroscopy were found to be in an acceptable position. The positive predictive value for acceptable screw placement with virtual fluoroscopy compared with traditional fluoroscopy was 99%. A probe placed with virtual fluoroscopic guidance will be judged to be in an acceptable position when imaged with traditional fluoroscopy 99% of the time.

Adult↗
PubMed2003

Craniocervical anomalies in Dubowitz syndrome. Three cases and a literature review.

Dubowitz syndrome is a disorder involving craniofacial abnormalities, growth retardation and mental retardation. Approximately 142 cases have been reported, with various associated other anomalies. These include cardiovascular, urogenital and endocrine abnormalities, as well as a predisposition to infections and hematological malignancies. Scoliosis has been described in association with this syndrome, as have isolated vertebral abnormalities. There has, however, been no description of craniocervical abnormalities. We describe three Dubowitz patients with significant craniocervical abnormalities.

Adult↗
PubMed2003

Microglia cyclooxygenase-2 activity in experimental gliomas: possible role in cerebral edema formation.

PURPOSE: Cerebral edema is responsible for significant morbidity and mortality in patients harboring malignant gliomas. To examine the role of inflammatory cells in brain edema formation, we studied the expression cyclooxygenase (COX)-2, a key enzyme in arachidonic acid metabolism, by microglia in the C6 rodent glioma model. EXPERIMENTAL DESIGN: The expression of COX-2 in primary microglia cultures obtained from intracranial rat C6 gliomas was examined using reverse transcription-PCR, Western analysis, and prostaglandin E(2) (PGE(2)) enzyme immunoassay. Blood-tumor barrier permeability was studied in the same tumor model using magnetic resonance imaging. RESULTS: In contrast to C6 glioma cells, microglia isolated from intracranial C6 tumors produced high levels of PGE(2) through a COX-2-dependent pathway. To test whether the observed microglia COX-2 activity played a role in brain edema formation in gliomas, tumor-bearing rats were treated with rofecoxib, a selective COX-2 inhibitor. Rofecoxib was as effective as dexamethasone in decreasing the diffusion of contrast material into the brain parenchyma (P = 0.01, rofecoxib versus control animals), suggesting a reduction in blood-tumor barrier permeability. CONCLUSIONS: These findings suggest that glioma-infiltrating microglia are a major source of PGE(2) production through the COX-2 pathway and support the use of COX-2 inhibitors as possible alternatives to glucocorticoids in the treatment of peritumoral edema in patients with malignant brain tumors.

Animals↗
PubMed2002

Anatomic suitability of the C1-C2 complex for pedicle screw fixation.

STUDY DESIGN AND OBJECTIVES: A computed tomography (CT) study of 60 consecutive patients (120 sides) was performed to assess suitability for either transarticular or pedicle screw fixation. SUMMARY OF BACKGROUND DATA: A C1 lateral mass and C2 pedicle screw fixation with a rigid cantilever beam system has been described. The anatomic constraints relevant for this technique have not. METHODS: Fifty consecutive patients underwent standard CT of the cervical spine. Pedicle and transarticular screw trajectories were plotted, and the maximum safe diameter for screw placement was determined for each trajectory. Also, trajectories were plotted in 10 additional patients with known craniocervical junction abnormalities using three-dimensional (3-D) imaging and computer-aided navigation tools. Screw placement was considered feasible if a 4-mm diameter trajectory could be plotted without impingement on neural or vascular structures. RESULTS: Four-millimeter diameter pedicle screws could be placed in 91 of 100 C2 pedicles in the CT studies and in 20 of 20 pedicles in the 3-D studies. Four-millimeter diameter C1-C2 transarticular screws could be placed in 94 of 100 sides in the CT study and in 19 of 20 sides in the 3-D study. Four sides could tolerate a C2 pedicle screw and not a transarticular screw; the opposite situation existed in five sides. Placement of screws into C1 was not an issue in any patient. The mean maximum diameter of potential transarticular screws was 6.5 mm, and the mean maximum diameter of the pedicle screws was 5.3 mm (P < 0.01). CONCLUSIONS: C1-C2 pedicle screw fixation is a technique that appears to be widely applicable and may represent an alternative fixation technique in selected patients.

Bone Screws↗
PubMed2002

C1-C2 pedicle screw fixation with rigid cantilever beam construct: case report and technical note.

OBJECTIVE AND IMPORTANCE: Transarticular screw fixation of the C1-C2 complex provides immediate rigid fixation of the unstable spine. The technique is not feasible in a certain proportion of patients because of the position of the vertebral artery or the patient's body habitus. CLINICAL PRESENTATION: The authors describe a rigid screw technique for the surgical treatment of a woman who was excluded as a candidate for C1-C2 transarticular screw fixation. TECHNIQUE: C1-C2 pedicle screw fixation was achieved using a fixed moment arm cantilever beam system. This system provided immediate rigid fixation of the C1-C2 complex in a patient who was not a candidate for transarticular screw fixation. CONCLUSION: This technique is technically more forgiving than posterior transarticular screw fixation and may be applied to a broader spectrum of patients.

Bone Screws↗
PubMed2002

Measuring the axial rotation of lumbar vertebrae in vivo with MR imaging.

BACKGROUND AND PURPOSE: Flexion-extension radiography is neither sensitive nor specific in the diagnosis of degenerative spinal instability, a presumed cause of back pain and an indication for spinal fusion. We tested the hypothesis that with MR imaging and a device to rotate the torso, axial rotations of lumbar vertebrae can be measured with sufficient accuracy and that significantly different rotations can be detected between lumbar segments with degenerated disks and those with normal disks. METHODS: We studied five volunteers without back pain (group 1), five patients who underwent MR imaging because of back pain but were not considered candidates for fusion (group 2), and five patients in whom diskography identified one or more disks with concordant pain (group 3). Each participant was placed on a specially built table that provided separate supports for the torso and for the hips and legs. Series of sagittal images were acquired with a T2-weighted fast spin-echo sequence, with the torso rotated clockwise and then counterclockwise. The amount of rotation was calculated from axial images with use of an automated program. RESULTS: In the five volunteers, rotations of the lumbar motion segments varied between -1.8 degrees and 5.7 degrees, with an average of 0.8 degrees. The abnormal disks in five patients in group 2 rotated from -0.9 degrees to 5.6 degrees, with an average of 3.2 degrees. In group 3, the disks in which concordant pain was elicited rotated from 0.8 degrees to 4.4 degrees, with an average of 2.2 degrees. Difference in rotation between abnormal and normal disks was statistically significant. CONCLUSION: Measurements of rotations of lumbar vertebrae with MR imaging may have value for determining levels that move abnormally in axial rotation.

Adult↗