Biomedical subjects

D K Resnick

Publications and source records attributed to D K Resnick.

At least 37 records · Page 2Linked to original sources

PubMed2002

Treatment of subaxial cervical spinal injuries.

UNLABELLED: SUBAXIAL CERVICAL FACET DISLOCATION INJURIES: STANDARDS: There is insufficient evidence to recommend treatment standards. GUIDELINES: There is insufficient evidence to recommend treatment guidelines. OPTIONS: Closed or open reduction of subaxial cervical facet dislocation injuries is recommended. Treatment of subaxial cervical facet dislocation injuries with rigid external immobilization, anterior arthrodesis with plate fixation, or posterior arthrodesis with plate or rod or interlaminar clamp fixation is recommended. Treatment of subaxial cervical facet dislocation injuries with prolonged bedrest in traction is recommended if more contemporary treatment options are not available. SUBAXIAL CERVICAL INJURIES EXCLUDING FACET DISLOCATION INJURIES: STANDARDS: There is insufficient evidence to recommend treatment standards. GUIDELINES: There is insufficient evidence to recommend treatment guidelines. OPTIONS: Closed or open reduction of subluxations or displaced subaxial cervical spinal fractures is recommended. Treatment of subaxial cervical spinal injuries with external immobilization, anterior arthrodesis with plate fixation, or posterior arthrodesis with plate or rod fixation is recommended.

Cervical Vertebrae↗

PubMed2002

Management of acute central cervical spinal cord injuries.

STANDARDS: There is insufficient evidence to support treatment standards. GUIDELINES: There is insufficient evidence to support treatment guidelines. OPTIONS: Intensive care unit (or other monitored setting) management of patients with acute central cervical spinal cord injuries, particularly patients with severe neurological deficits, is recommended. Medical management, including cardiac, hemodynamic, and respiratory monitoring, and maintenance of mean arterial blood pressure at 85 to 90 mmHg for the first week after injury to improve spinal cord perfusion is recommended. Early reduction of fracture-dislocation injuries is recommended. Surgical decompression of the compressed spinal cord, particularly if the compression is focal and anterior, is recommended.

Acute Disease↗

PubMed2002

Management of vertebral artery injuries after nonpenetrating cervical trauma.

DIAGNOSTIC STANDARDS: There is insufficient evidence to support diagnostic standards. GUIDELINES: There is insufficient evidence to support diagnostic guidelines. OPTIONS: Conventional angiography or magnetic resonance angiography is recommended for the diagnosis of vertebral artery injury after nonpenetrating cervical trauma in patients who have complete cervical spinal cord injuries, fracture through the foramen transversarium, facet dislocation, and/or vertebral subluxation. TREATMENT STANDARDS: There is insufficient evidence to support treatment standards. GUIDELINES: There is insufficient evidence to support treatment guidelines. OPTIONS: Anticoagulation with intravenous heparin is recommended for patients with vertebral artery injury who have evidence of posterior circulation stroke. Either observation or treatment with anticoagulation in patients with vertebral artery injuries and evidence of posterior circulation ischemia is recommended. Observation in patients with vertebral artery injuries and no evidence of posterior circulation ischemia is recommended.

Evidence-Based Medicine↗

PubMed2001

GeneChip analysis after acute spinal cord injury in rat.

Spinal cord injury (SCI) leads to induction and/or suppression of several genes, the interplay of which governs the neuronal death and subsequent loss of motor function. Using GeneChip, the present study analyzed changes in the mRNA abundance at 3 and 24 h after SCI in adult rats. SCI was induced at T9 level by the New York University impactor by dropping a 10-g weight from a height of 25 mm. Several transcription factors, immediate early genes, heat-shock proteins, pro-inflammatory genes were up-regulated by 3 h, and persisted at 24 h, after SCI. On the other hand, some neurotransmitter receptors and transporters, ion channels, kinases and structural proteins were down-regulated by 3 h, and persisted at 24 h, after SCI. Several genes that play a role in growth/differentiation, survival and neuroprotection were up-regulated at 24 h after SCI. Using real-time quantitative PCR, the changes observed by GeneChip were confirmed for seven up-regulated (interleukin-6, heat-shock protein-70, heme oxygenase-1, suppressor of cytokine signaling 2, suppressor of cytokine signaling 3, interferon regulatory factor-1, neuropeptide Y), two down-regulated (vesicular GABA transporter and cholecystokinin precursor) and two unchanged (Cu/Zn-superoxide dismutase and phosphatidyl inositol-3-kinase) genes. The present study shows that inflammation, neurotransmitter dysfunction, increased transcription, ionic imbalance and cytoskeletal damage starts as early as 3 h after SCI. In addition to these effects, 24 h after SCI the repair and regeneration process begins in an attempt to stabilize the injured spinal cord.

Acute Disease↗

PubMed2000

Gliosarcoma metastatic to the cervical spinal cord: case report and review of the literature.

BACKGROUND: We describe a case of an intramedullary metastasis to the cervical spinal cord from a temporal gliosarcoma. CASE DESCRIPTION: A 48-year-old man with known temporal lobe gliosarcoma presented with a new onset of ipsilateral hemiparesis. A MRI scan revealed the presence of an intramedullary lesion in the spinal cord behind the body of C2. Despite repeated craniotomy, radiation, and chemotherapy, the patient succumbed to a rapidly progressive disease. CONCLUSION: The case illustrates the ability of gliosarcoma to metastasize to other locations in the neuroaxis. We believe this to be the first case report of an intramedullary spinal cord metastasis from a gliosarcoma. The pathological features and available literature are reviewed.

Brain Neoplasms↗

PubMed2000

Neuroscience education of undergraduate medical students. Part I: role of neurosurgeons as educators.

OBJECT: Economic, demographic, and political pressures have mandated that medical schools increase the number of primary care physicians. The goal of this study was to determine the nature of the average medical student's exposure to neurosurgical issues. METHODS: Surveys were sent to every neurosurgical program director in the United States and to the dean of every medical school in North America, querying the extent of neurosurgical involvement in medical student education. Specifically, the respondents were asked how medical students were educated about the management of low-back pain and radiculopathy, carotid artery disease, head and spine trauma, and headache. Survey results were obtained from 65 (67%) of 97 neurosurgery program directors and from 57 (40%) of 143 medical school deans. Only one program in North America reported having a required neurosurgical rotation for all medical students, and just over 50% (29 of 57 deans and 34 of 65 program directors) reported that neurosurgery was an option in a required neuroscience or surgical subspecialty course. Neurosurgeons were not listed among the top three sources for medical student education in the topics of low-back pain and radiculopathy or carotid artery disease. Neurosurgeons were the most frequently cited source of education regarding head and spinal injuries, despite the fact that the majority of medical schools do not have any required medical student exposure to neurosurgery. CONCLUSIONS: With rare exceptions, neurosurgeons are not significantly involved in the education of medical students concerning the management of common neurosurgical issues. As a result, most emerging primary care physicians are taught about these issues by other specialists or not at all. The implications of this situation are discussed.

Carotid Artery Diseases↗

PubMed2000

Neuroscience education of undergraduate medical students. Part II: outcome improvement.

OBJECT: Because of political and economic pressures, primary care physicians are now charged with greater responsibility for the care of patients with disease processes definitively managed by neurosurgeons. The goal of this study was to establish the feasibility and efficacy of a neurosurgical curriculum designed to teach future primary care physicians about these diseases. METHODS: A compact, seven-lecture curriculum was developed to teach 3rd-year medical students about degenerative spine disease, stroke, tumor- and hydrocephalus-related raised intracranial pressure, head and spine injury, and subarachnoid hemorrhage. This curriculum was given as part of a 6-week pilot course that included neurology, neurosurgery, ophthalmology, and rehabilitation medicine components. This course was administered to two groups of 18 medical students, and an examination was administered at the end of the pilot course. The same examination was administered to an additional 19 students immediately after their completion of the neurology course currently required. Students enrolled in the pilot neuroscience course performed significantly better (p<0.001) on the examination than those who had completed the standard neurology course. Striking improvements were noted in the recognition and management of head injury, hydrocephalus, and radiculopathy. CONCLUSIONS: Inclusion of a short neurosurgery-related curriculum in a combined neuroscience course significantly improved student performance on an examination focusing on the recognition and management of common neurosurgical disorders. Because primary care physicians are responsible for the initial recognition and management of these disorders, the knowledge gained may lead to improved patient care.

Brain Neoplasms↗

PubMed1999

Differential expressions of CD44 variants in tumors affecting the central nervous system.

BACKGROUND: The polymorphic cell adhesion molecule CD44 exists as a family of proteins generated by extensive alternative splicing of the CD44 pre-messenger RNA and marked posttranslational modification. The differential expression of CD44 isoforms in a variety of human cancers has been proposed to influence tumorigenesis and metastasis. In this study, CD44 gene expression was analyzed in primary and metastatic tumors and in cell lines derived from tumors that affect the central nervous system (CNS), including tumors metastatic to the spine. MATERIALS AND METHODS: Fifty-four samples were subjected to semiquantitative reverse-transcriptase polymerase chain reaction with CD44-specific primers and hybridized individually with probes specific for the CD44 variant (CD44v) exons v3 to v10. RESULTS: Compared with CD44v-positive breast cancer cell lines and CD44v-negative normal brain tissue, CD44v expression was weak in primary brain tumors and cell lines derived from normal brain and tumor tissue. However, high levels of isoforms encoding multiple-variant exons were shown in all metastatic brain tumors. In contrast, tumors metastatic to the spine were virtually negative for CD44v expression. Several rare CD44 isoforms composed of single-variant exons v3, v4, v6, or v9 were identified in primary brain tumors and may reflect their invasive potential or culturability in vitro. CONCLUSION: These data suggest differential expression of CD44v may substantially influence the end-organ site of metastasis for tumor cells destined for the CNS.

Antigens, Neoplasm↗

PubMed1999

Cervical spine evaluation in obtunded or comatose pediatric trauma patients: A pilot study.

A uniformly accepted protocol for evaluation and clearance of the cervical spine of pediatric trauma patients with altered mental status does not currently exist. We sought to detect cervical spine injuries in this group with minimal risk. Patients were evaluated with standard three-view cervical spine radiographs and CT when necessary. Those patients without radiographic abnormality and altered mental status underwent flexion-extension of the cervical spine using fluoroscopy with somatosensory evoked potential (SSEP) monitoring. Those with abnormal movement by fluoroscopy or changes in SSEP underwent MRI. Fifteen patients were evaluated with this protocol. Two patients had movement on flexion-extension of the cervical spine and 5 had SSEP changes. Three patients had an MRI with only 1 showing injury. Five patients had residual hemiparesis. Evaluation of the cervical spine in obtunded or comatose pediatric trauma patients can be done safely with flexion-extension under fluoroscopy and SSEP monitoring. Further prospective studies are required to determine the efficacy of SSEP monitoring for cervical spine clearance in this select population.

Adolescent↗

PubMed1999

Microvascular decompression of cranial nerves: lessons learned after 4400 operations.

OBJECT: Microvascular decompression has become an accepted surgical technique for the treatment of trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia, and other cranial nerve rhizopathies. The senior author (P.J.J.) began performing this procedure in 1969 and has performed more than 4400 operations. The purpose of this article is to review some of the nuances of the technical aspects of this procedure. METHODS: A review of 4415 operations shows that numerous modifications to the technique of microvascular decompression have occurred during the last 29 years. Of the 2420 operations performed for trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia before 1990, cerebellar injury occurred in 21 cases (0.87%), hearing loss in 48 (1.98%), and cerebrospinal fluid (CSF) leakage in 59 cases (2.44%). Of the 1995 operations performed since 1990, cerebellar injuries declined to nine cases (0.45%), hearing loss to 16 (0.8%), and CSF leakage to 37 (1.85% p < 0.01, test for equality of distributions). The authors describe slight variations made to maximize surgical exposure and minimize potential complications in each of the six principal steps of this operation. These modifications have led to decreasing complication rates in recent years. CONCLUSIONS: Using the techniques described in this report, microvascular decompression is an extremely safe and effective treatment for many cranial nerve rhizopathies.

Arteries↗

PubMed1999

Hyperactive rhizopathy of the vagus nerve and microvascular decompression. Case report.

A 37-year-old woman underwent microvascular decompression of the superior vestibular nerve for disabling positional vertigo. Immediately following the operation, she noted severe and spontaneous gagging and dysphagia. Multiple magnetic resonance images were obtained but failed to demonstrate a brainstem lesion and attempts at medical management failed. Two years later she underwent exploration of the posterior fossa. At the second operation, the vertebral artery as well as the posterior inferior cerebellar artery were noted to be compressing the vagus nerve. The vessels were mobilized and held away from the nerve with Teflon felt. The patient's symptoms resolved immediately after the second operation and she has remained symptom free. The authors hypothesize that at least one artery was shifted at the time of her first operation, or immediately thereafter, which resulted in vascular compression of the vagus nerve. To the authors' knowledge, this is the first reported case of a hyperactive gagging response treated with microvascular decompression. The case also illustrates the occurrence of a possibly iatrogenic neurovascular compression syndrome.

Adult↗

PubMed1998

Role of cyclooxygenase 2 in acute spinal cord injury.

Cyclooxygenase, or prostaglandin G/H synthase, is the rate-limiting step in the production of prostaglandins. A new isoform, cyclooxygenase-2 (COX-2), has been cloned that is induced during inflammation in leukocytes and by synaptic activity in neurons. The objectives of this study are to determine the nature of COX-2 expression in normal and traumatized rat spinal cord, and to determine the effects of selective COX-2 inhibition on functional recovery following spinal cord injury. Using a weight-drop model of spinal cord injury, COX-2 mRNA expression was studied with in situ hybridization. COX-2 protein expression was examined by immunohistochemistry and Western analysis. Finally, using the highly selective COX-2 inhibitor, 1-[(4-methylsufonyl)phenyl]-3-tri-fluro-methyl-5-[(4-flur o)phenyl]prazole (SC58125), the effect of COX-2 inhibition on functional outcome following a spinal cord injury was determined. COX-2 was expressed in the normal adult rat spinal cord. COX-2 mRNA and protein production were increased following injury with increases in COX-2 mRNA production detectable at 2 h following injury. Increased levels of COX-2 protein were detectable for at least 48 h following traumatic spinal cord injury. Selective inhibition of COX-2 activity with SC58125 resulted in improved mean Basso, Beattie, and Bresnahan scores in animals with 12.5- and 25-g/cm spinal cord injuries; however, the effect was significant only for the 12.5g/cm injury group (p=0.0001 vs. p=0.0643 in the 25-g/cm group). These data demonstrate that COX-2 mRNA and protein expression are induced by spinal cord injury, and that selective inhibition of COX-2 improves functional outcome following experimental spinal cord injury.

Acute Disease↗

PubMed1998

Lateral extracavitary approach for thoracic and thoracolumbar spine trauma: operative complications.

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. PATIENTS AND METHODS: A retrospective chart review of all patients with acute fractures or dislocations of the thoracic or thoracolumbar spine who underwent surgery via the LECA was conducted to assess the incidence and type of perioperative complications associated with the LECA. RESULTS: Thirty-three patients with thoracic or thoracolumbar spine injuries treated using the LECA between June 1990 and June 1996 were identified and had available medical records. Complications occurred in 18 of these patients. Pulmonary complications predominated. Eleven patients required tube thoracostomy for hemothorax or persistent pleural effusions, and seven patients developed postoperative pneumonia. There were no cases of neurological worsening. There was no mortality. CONCLUSION: Decompression and stabilization of acute thoracolumbar fractures with the LECA in the acute setting is associated with a 55% incidence of morbidity. Whereas some of this morbidity may be attributed to the effects of the injury, there is a certain intrinsic morbidity associated with the LECA. Although this morbidity may compare favorably with that of sequential ventral/dorsal approaches, the biomechanical advantages obtained with a combined ventral and dorsal construct must be balanced against the inherent morbidity of such approaches.

Decompression, Surgical↗

PubMed1998

Microvascular decompression for pediatric onset trigeminal neuralgia.

BACKGROUND: Trigeminal neuralgia (TGN) is generally a disease of the elderly. Vascular compression, the causative agent in the majority of cases, is thought to result from atherosclerotic changes within the vessels of the posterior fossa. Rarely, the disease presents during childhood, before the onset of severe atherosclerotic changes. We therefore sought to explore the role of vascular compression in pediatric patients with medically refractory TGN. PATIENTS AND METHODS: Twenty-three patients were identified in whom the onset of typical TGN had occurred during childhood (age 18 yr or younger) and who underwent exploration of the cerebellopontine angle. Twenty-two of 23 underwent microvascular decompression (MVD) of the trigeminal nerve. Twenty-one of these patients were followed for more than 1 year. A retrospective chart review was conducted to determine the efficacy of MVD for the treatment of TGN in this select population. Operative findings were recorded and correlated with patient outcome. RESULTS: Twenty-two of 23 patients (96%) were found to have vascular compression of the trigeminal nerve at the time of exploration. One patient was found to have an epidermoid tumor. MVD resulted in complete pain relief at the time of discharge in 16 of 22 patients (73%), with an additional 4 patients (18%) having a greater than 75% diminution of pain. The 21 patients who were followed for at least 1 year were followed for a mean of 105 months. At the time of their last follow-up, 9 of these patients (43%) continued to have complete pain relief and 3 (14%) had a greater than 75% diminution of pain. The most common operative finding was a vein compressing the nerve, often in combination with a branch of the superior cerebellar artery. DISCUSSION: MVD has been demonstrated to be a safe and efficacious treatment for TGN in the adult population. Patients whose symptoms begin in childhood do not enjoy the same therapeutic response to MVD as do patients with TGN onset in adulthood. An increased incidence of venous compression was noted in this population, as was a longer duration of symptoms before MVD. These factors may be responsible for the decreased efficacy of MVD in this patient population.

Adolescent↗

PubMed1997

Outcome analysis of patients with severe head injuries and prolonged intracranial hypertension.

OBJECTIVE: To describe the functional outcome of a select group of patients with severe head injuries who would a priori be assumed to have a dismal outcome and to determine prognostic factors that can be used for effective family counseling and rational utilization of scarce resources. METHODS: Thirty-seven patients with severe head injuries (admission Glasgow Coma Scale (GCS) score < 8) with prolonged (> 96 hours) intracranial hypertension were studied. Parameters recorded included admission age, GCS, evidence of prehospital hypotension, initial computed tomography findings, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and therapeutic intensity level. RESULTS: Thirty-eight percent of patients in this study achieved a Glasgow Outcome Scale score (GOS) of 4 (moderate disability) or better when assessed 1 year after injury. Patients who achieved these good outcomes were significantly younger (mean 23.6 +/- 8.8 years) than patients who were severely disabled or worse (GOS 1-3) (34.3 +/- 15.0 years) (p = 0.0098). The mean admission GCS in the good-outcome group tended to be higher than that of the poor-outcome group (5.8 +/- 1.5 vs 4.8 +/- 1.6, p = 0.065). When patients with good outcomes (GOS 4 or 5) were compared with those with poor outcomes (GOS 1-3), no significant differences in mean or peak ICP, percentage of time intervals with elevated ICP, lowest recorded CPP, or length of ICP monitoring were detected. CONCLUSION: Younger patients, particularly those with GCS > 5, have the potential for excellent recovery despite prolonged (> 96 hours) intracranial hypertension. These patients will benefit from continued aggressive ICP and CPP management.

Adult↗

PubMed1997

The significance of carotid canal involvement in basilar cranial fracture.

OBJECTIVE: Basilar cranial fractures have been associated with injury to the carotid artery. We sought to determine whether fracture through the carotid canal was a significant risk factor for carotid injury. METHODS: A retrospective chart review was performed, and 230 patients with basilar cranial fractures were identified. Fifty-five of the 230 patients had visible fractures that extended through one or both carotid canals (CC fx group). Evidence for vascular injury, based on medical records, angiography, magnetic resonance imaging, and other studies, was compiled. The anatomic characteristics of the fractures were also noted and recorded. RESULTS: Ten patients in the CC fx group suffered vascular complications; for six of them, the complications were directly related to the intracranial carotid artery. This compares to four patients in the non-CC fx group with vascular complications (P < 0.005), only one of which was carotid-specific (P < 0.005). The most common site of fracture through the canal was at the junction of the lacerum and cavernous portions of the canal (the spheno-occipital suture) (62% of all carotid canal fractures occurred at that site); however, vascular injury was seen most often in patients who sustained fractures through the petrous segment (67% of carotid canal-specific injuries occurred in that group, and 25% of patients with petrous canal fractures suffered carotid injury, [P = not significant]). The mean Glasgow Coma Scale score and the mean age were both lower (P < 0.05) in the CC fx group. CONCLUSION: Vascular complications are more frequently observed after basilar cranial fractures when there is involvement of the carotid canal. The lacerum-cavernous junction, which is partly formed by the spheno-occipital suture, is the most frequently fractured segment of the carotid canal. Fracture through the petrous segment of the carotid canal is associated with a relatively high incidence of carotid injury. Fracture through the carotid canal may serve as an index of injury severity, because patients with these fractures suffered more severe head injuries.

Adolescent↗

PubMed1997

Pediatric hemifacial spasm: the efficacy of microvascular decompression.

Hemifacial spasm (HFS), generally a disease of the elderly, is caused by vascular compression of the seventh nerve. Vascular compression is thought to result from atherosclerotic changes within the vessels of the posterior fossa, and therefore rarely presents in childhood. Here we describe our experience with 12 patients with onset of HFS during childhood (age 18 or less) and who had surgical exploration of the cerebellopontine angle. These patients represent less than 1.2% of the patient population with HFS operated upon at this institution during the study period. Nine patients had follow-up data extending over 83 months. All 12 patients were found to have microvascular compression of the seventh nerve at the time of surgery. The most common operative finding was compression of the seventh nerve by a vein, alone or in combination with a branch of the anterior inferior cerebellar artery. At the time of discharge and after a mean follow-up period of 125 months, microvascular decompression resulted in complete relief of spasm in 67% of the patients.

Adolescent↗

PubMed1997

Primary endodermal sinus tumor presenting with spinal cord compression. Case report.

Endodermal sinus tumor is an uncommon malignant germ-cell neoplasm. These tumors usually present in childhood or young adulthood as testicular or ovarian masses; however, mediastinal and intracranial tumors have been described. The authors report the occurrence of a primary paraspinal endodermal sinus tumor in a 21-month-old boy who presented with thoracic spinal cord compression. A review of the literature failed to reveal a similar case. The clinical presentation, radiographic characteristics, operative findings, and patient outcome are discussed.

Endodermal Sinus Tumor↗