Biomedical subjects

Daniel K Resnick

Publications and source records attributed to Daniel K Resnick.

At least 37 records · Page 2Linked to original sources

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 9: fusion in patients with stenosis and spondylolisthesis.

The best medical evidence available in the literature confirms the utility of fusion for improving patient outcomes following decompression for stenosis associated with spondylolisthesis. The majority of evidence from other studies comparing outcomes after decompression alone or decompression combined with PLF in patients with stenosis and spondylolisthesis also favors the performance of PLF. The medical evidence regarding the use of pedicle screw fixation in this patient population is rated as Class III and is inconsistent. A consistent benefit associated with the use of pedicle screw fixation has been reported in patients with preoperative instability or kyphosis. Iatrogenic instability following decompression is associated with poor outcomes and may also be treated with PLF involving supplemental instrumentation. The precise definition of instability or kyphosis has varied among researchers and requires further study.

Humans↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 10: fusion following decompression in patients with stenosis without spondylolisthesis.

Based on the medical evidence derived from the scientific literature on this topic, there does not appear to be evidence to support the hypothesis that fusion (with or without instrumentation) provides any benefit over decompression alone in the treatment of lumbar stenosis in patients in whom there is no evidence of preoperative deformity or instability. A single report provides Class II medical evidence and several papers provide Class III medical evidence suggesting that the addition of fusion to decompression in patients with lumbar stenosis and instability evidenced by movement on preoperative flexion-extension radiographs does improve outcome. There are also reports (Class III medical evidence) indicating that patients with lumbar stenosis, without deformity or instability, treated with wide decompression or facetectomy may suffer iatrogenic lumbar instability. Fusion in these patients may improve outcome. There is conflicting Class III medical evidence regarding the application of instrumentation in addition to PLF in patients treated for lumbar stenosis without deformity or preoperative instability.

Decompression, Surgical↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 11: interbody techniques for lumbar fusion.

The majority of reviewed medical evidence suggests that interbody techniques are associated with higher fusion rates compared with PLF when applied to patients with low-back pain due to DDD limited to one or two levels. The evidence is generally of poor quality and retrospective in nature. Conflicting evidence exists supporting the role of interbody graft placement for improvement of functional outcomes; however, there is no Class I or II evidence to suggest that the use of an interbody graft is associated with worse outcomes, and Class II evidence exists to suggest that outcomes are improved. Complication rates of interbody graft placement, particularly of circumferential procedures, are higher in most series. Many complications, however, are associated with pedicle screw fixation and not with interbody graft placement per se. In the context of a single-level stand-alone ALIF or ALIF with posterior instrumentation, there does not appear to be a substantial benefit to the addition of a PLF. The addition of a PLF to a construct that already includes an interbody graft is, however, associated with increased costs and complications. Therefore, although the addition of supplemental fixation (a 270 degrees fusion) may be necessary for biomechanical reasons, it may not be appropriate to subject the patient to the morbidity of a full posterior exposure for placement of graft material. Significant differences in clinical outcomes between the various interbody techniques have not been convincingly demonstrated. No general recommendation can therefore be made regarding the technique that should be used to achieve interbody fusion.

Humans↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 12: pedicle screw fixation as an adjunct to posterolateral fusion for low-back pain.

This review focused on an examination of the literature on the surgical treatment of low-back pain in patients with DDD or low-grade degenerative spondylolisthesis treated with PLF, with or without the use of pedicle screw fixation. All Class I and the majority of Class II and Class III medical evidence on this topic indicates that the addition of pedicle screw fixation to PLF increases fusion success rates when assessed based on plain x-ray films with dynamic imaging. Although there does appear to be a positive relationship between radiographic fusion and clinical outcome, no convincing correlation has been demonstrated. Although several reports suggest that clinical outcomes are improved with the addition of pedicle screw fixation, there are conflicting findings from similarly classified evidence sources (primarily Class II and III). Furthermore, the largest contemporary randomized controlled study on this topic failed to demonstrate a significant beneficial effect for the use of pedicle screw fixation in patients treated with PLF for chronic low-back pain. This absence of proof should not, however, be interpreted as a proof of absence. For example, in this same study, patient satisfaction scores improved from approximately 60% to approximately 70% with the addition of pedicle screw fixation. This difference in outcome may be clinically relevant. Similarly, the improvement in ODI scores was 40% greater in the group of patients treated with pedicle screw fixation compared with those treated with PLF alone. If an analysis to determine the sample size necessary to ensure a power of 0.8 (or an 80% chance of detecting a significant effect) in a study in which the good outcome rate is 60% in the control group and 70% in the treatment group is performed, approximately 355 patients would be needed in each treatment group (http://department.obg.cuhk.edu.hk). Alternatively, if a similar analysis is performed using the differential scores obtained in the ODI measurements reported in the paper by Fritzell, et al., approximately 225 patients would be needed per treatment group (http://calculators.stat.ucla.edu/powercalc). Although Fritzell, et al., did not detect a significant benefit associated with the use of pedicle screw fixation as an adjunct to PLF, their sample size severely limited the power of their study to detect such a benefit. All studies reviewed suffer from similar lack of power. Therefore, no definitive statement regarding the efficacy of pedicle screw fixation as a means to improve functional outcomes in patients undergoing PLF for chronic low-back pain can be made. There appears to be consistent evidence suggesting that pedicle screw fixation increases the costs and complication rate of PLF. It is recommended, therefore, that the use of pedicle screw fixation as a supplement to PLF be reserved for those patients in whom there is an increased risk of nonunion when treated with PLF. High-risk patients include, but are not limited to patients who smoke, who are undergoing revision surgery, or who suffer systemic diseases known to be associated with poor bone healing.

Bone Screws↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 13: injection therapies, low-back pain, and lumbar fusion.

In summary, there is no meaningful evidence in the medical literature that the use of epidural injections is of any long-term value in the treatment of patients with chronic low-back pain. The literature does indicate that the use of lumbar epidural injections can provide short-term relief in selected patients with chronic low-back pain. There is evidence that suggests that facet joint injections can be used to predict outcome after RF ablation of a facet joint. The predictive ability of facet joint injections does not appear to apply to lumbar fusion surgery. No evidence exists to support the effectiveness of facet injections in the treatment of patients with chronic low-back pain. There is conflicting evidence suggesting that the use of local TPIs can be effective for the short-term relief of low-back pain. There are no data to suggest that TPIs with either steroids or anesthetics alone provide lasting benefit for patients suffering from chronic low-back pain.

Anesthetics↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 14: brace therapy as an adjunct to or substitute for lumbar fusion.

Although conflicting reports have been presented in the literature regarding the utility of lumbar braces for the prevention of low-back pain, most Class III medical evidence suggests that these supports used prophylactically do not reduce the incidence of low-back pain or decrease the amount of time lost from work in the general working population. Among workers with a history of a back injury, their use appears to decrease the number of work days lost due to back pain. Lumbar braces appear to be an effective treatment for acute low-back pain in some populations. They do not appear to be effective in the chronic low-back pain population. If a brace is used, rigid braces offer some benefit over soft braces. There are no data to suggest that relief of low-back pain with preoperative external bracing predicts a favorable outcome following lumbar spinal fusion. No information is available on the benefit of bracing for improving fusion rates or clinical outcomes following instrumented lumbar fusion for degenerative disease.

Braces↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 15: electrophysiological monitoring and lumbar fusion.

Based on the medical evidence provided by the literature reviewed, there does not appear to be support for the hypothesis that any form of intraoperative monitoring improves patient outcomes following lumbar decompression or fusion procedures for degenerative spinal disease. Evidence does indicate that a normal evoked EMG response is predictive for intrapedicular screw placement (high NPV for breakout). The presence of an abnormal EMG response does not, however, exclude intrapedicular screw placement (low PPV). The majority of clinically apparent postoperative nerve injuries are associated with intraoperative changes in SSEP and/or DSEP monitoring. For this reason, changes in DSEP/SSEP monitoring appear to be sensitive to nerve root injury. There is a high-false positive rate, however, and changes in DSEP and SSEP recordings are frequently not related to nerve injury. A normal study has been shown to correlate with the lack of a significant postoperative nerve injury. There is no substantial evidence to indicate that the use of intraoperative monitoring of any kind provides useful information to the surgeon in terms of assessing the adequacy of nerve root decompression at the time of surgery.

Electromyography↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 16: bone graft extenders and substitutes.

Despite the large volume of animal data regarding the use of synthetic bone graft substitutes or extenders, there are very few data regarding the use of these substances for fusion in lumbar degenerative disease. The best available data indicate that rhBMP-2 is a viable alternative to autograft bone for interbody fusion procedures. This same substance may also be a viable alternative to autograft for PLF; however, definitive medical evidence is not yet available. There is little, if any, medical evidence to support the use of other biological agents at the present time. As promising new compounds are brought to market, well-designed cohort studies and randomized trials will be required to determine the actual usefulness of these compounds in clinical practice. It is important not to generalize the results obtained with one preparation or application to different preparations or applications. The use of synthetic calcium phosphate ceramics as graft extenders appears to be reasonable in certain situations. The medical evidence available regarding their use is limited and of poor quality. Further study will be required to establish their utility for use in spinal fusion.

Bone Substitutes↗

PubMed2005

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 17: bone growth stimulators and lumbar fusion.

There have been a number of randomized studies supporting the use of ES for the promotion of bone healing following lumbar fusion. All of the published studies have methodological flaws that prevent the studies from providing Class I medical evidence. There is, however, Class II and III evidence to support the use of direct current stimulation or CCS for enhancing fusion rates in high-risk patients undergoing lumbar PLF. A beneficial effect on fusion rates in patients not at "high risk" has not been convincingly demonstrated, nor has an effect been shown for these modalities in patients treated with interbody fusion. There is limited evidence both for and against the use of PEMFS for enhancing fusion rates following PLE Class II and III medical evidence supports the use of PEMFS for promoting arthrodesis following interbody fusion. Although some studies have purported to demonstrate functional improvement in some patient subgroups, other studies have not detected differences. All of the reviewed studies are significantly flawed by the use of a four-point patient satisfaction scale as the primary outcome measure. This outcome measure is not validated. Because of the use of this flawed outcome measure and because of the conflicting results reported in the better-designed studies that assess functional outcome, there is no consistent medical evidence to support or refute use of these devices for improving patient outcomes.

Combined Modality Therapy↗

PubMed2004

Molecular evidence of repair and plasticity following spinal cord injury.

Investigations into the genetic basis of neuronal damage following spinal cord injury have thus far been limited to the acute phase after the injury. Using microarray analysis, the present study compared the spinal-cord-injury-induced gene expression changes in adult rats at the epicenter and rostral segments of spinal cord at acute (12 h) and delayed (42 days) time points. We have previously reported that the acute response to spinal cord injury involves alterations in genes responsible for inflammation, cell cycle alteration, and altered receptor function. In contrast, the delayed response includes changes in the expression of HSP27, MAG, MAP-2, IGF-1 and ApoE. The alteration in expression of these genes suggests an ongoing repair process in animals whose functional recovery has reached a plateau.

Animals↗

PubMed2003

Evidence-based review of the surgical management of vertebral column metastatic disease.

OBJECT: Significant controversy exists over the most appropriate treatment for patients with metastatic disease of the vertebral column. Treatment options include surgical intervention, radiotherapy, or a combination of the two; nevertheless, a standard of care that yields the best survival, outcome, and quality of life has not been established. The purpose of this review was to determine the foundation in the literature of views favoring surgical intervention for spinal metastatic disease. METHODS: A search of the English-language literature published between 1964 and 2003 was performed for the subject of spinal metastatic disease. Papers were selected based on the inclusion criteria described, and evidentiary information was compiled and graded using previously described methods. CONCLUSIONS: Although there is insufficient evidence to support a standard for surgical treatment in patients with metastatic spinal disease, the authors present guidelines and recommendations based on the evidence provided by the current literature.

Combined Modality Therapy↗

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

Delayed esophageal injury without instrumentation failure: complication of anterior cervical instrumentation.

The authors describe a case of a 67-year-old man who presented with a delayed esophageal perforation 4 years after anterior cervical spine surgery for spondylotic myelopathy. Diagnosis was made with esophagoscopic visualization of the lesion and repair performed with hardware removal and esophageal closure utilizing a sternocleidomastoid muscle flap. The pertinent literature is reviewed and the therapeutic implications discussed.

Aged↗

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

Guidelines for the use of discography for the diagnosis of painful degenerative lumbar disc disease.

OBJECT: Discography has been used as a diagnostic test in the evaluation of patients with recalcitrant low-back pain. Recently, its usefulness has been questioned because of the occurrence of false-positive results as well as the influence of psychological factors on test results. The purpose of this review is to establish the literature support for and against the use of discography. A search of the English-language literature published between 1966 and 2001 was performed. Papers were selected based on inclusion criteria described in the text, and the quality of information was graded using previously described methods. CONCLUSIONS: The authors propose a set of practice parameters based on the literature. Although the data were not judged adequate for the determination of a treatment standard, parameters for the use of discography are provided at a guideline and option level.

Humans↗

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↗