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Biomedical subjects

D K Resnick

Publications and source records attributed to D K Resnick.

18 recordsLinked to original sources
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↗
PubMed1997

Biomechanics of the thoracolumbar spine.

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. Patterns of failure due to supraphysiologic loading or through the loss of structural integrity may be predicted based on the applied force vectors and the stabilization components lost. An understanding of these forces and their effects on the spine is crucial for the safe and efficacious treatment of spinal deformities.

Biomechanical Phenomena↗
PubMed1996

Rosai-Dorfman disease presenting with multiple orbital and intracranial masses.

Rosai-Dorfman disease is an idiopathic histocytic proliferative disorder typically characterized by painless cervical adenopathy, fever, and weight loss. Extranodal manifestations are responsible for presentation in approximately 25% of patients. Orbital involvement has been described in about 10% of patients. There have been only 16 reported cases of Rosai-Dorfman disease presenting with an intracranial mass. We report an unusual case of a patient presenting with bilateral orbital tumors as well as multiple intracranial masses. Clinical, magnetic resonance imaging, and histopathological features are discussed.

Adult↗
PubMed1996

Microvascular decompression for trigeminal neuralgia in patients with multiple sclerosis.

BACKGROUND: Microvascular decompression (MVD) of the trigeminal nerve is a well-established procedure for the treatment of idiopathic trigeminal neuralgia. Multiple sclerosis (MS) has long been considered a contraindication for this procedure, due to the known polycentric nature of the disease. Medical treatment followed by percutaneous procedures provide relief for the great majority of these patients. There exists a small subgroup of patients with trigeminal neuralgia who are diagnosed with MS only after a microvascular decompression procedure has been performed. Furthermore, management of the patient with known MS whose pain continues to recur, despite maximal medical therapy and multiple percutaneous procedures, can be exceedingly difficult. METHODS: Five patients with MS, three who had undergone multiple unsuccessful percutaneous procedures and two in whom the diagnosis of MS had not been established, underwent exploration of the cerebellopontine angle. Three patients underwent MVD alone, and two (both with known MS) underwent MVD and partial section of the trigeminal nerve. RESULTS: Patients who underwent microvascular decompression alone did not have satisfactory relief of pain. Patients who underwent partial sectioning of the nerve did better. CONCLUSIONS: Patients with MS and symptoms of typical trigeminal neuralgia may benefit from exploration of the cerebellopontine angle and partial sectioning of the nerve. MVD alone fails to provide adequate or reliable relief of pain.

Adult↗
PubMed1996

The relationship of blood velocity as measured by transcranial doppler ultrasonography to cerebral blood flow as determined by stable xenon computed tomographic studies after aneurysmal subarachnoid hemorrhage.

Transcranial doppler (TCD) ultrasonography is often used to guide the management of patients with subarachnoid hemorrhage (SAH). However, the correlation between increased blood velocity as measured by TCD ultrasonography and angiographic vasospasm was established before the routine use of hypervolemia/hemodilution and administration of nimodipine and did not address blood flow. The relationship of blood velocity as measured by TCD ultrasonography and local cerebral blood flow (LCBF) in SAH managed with these modalities is unknown. Patients presenting with aneurysmal SAH between January 1992 and September 1993 who underwent TCD ultrasonography and xenon computed tomographic (Xe/CT) LCBF studies within 12 hours were retrospectively studied. Fifty patients underwent a total of 94 paired studies, encompassing 709 vascular territories. All were treated with nimodipine and hypervolemia/hemodilution. Hematocrit, blood pressure, and partial carbon dioxide pressure were similar at the time of TCD ultrasonography and Xe/CT measurement of LCBF. When LCBF in the middle cerebral artery (MCA) was < or = 31 ml/100 g/min, the corresponding peak systolic velocity measured by TCD ultrasonography was 119 cm/s, whereas those > 31 ml/100 g/min had a velocity of 169 cm/s (P = 0.006). High LCBF was associated with high velocity in all vascular territories, reaching significance in all but the internal carotid artery. At the time of each study, 41 neurological examinations were focal and 53 were nonfocal. The Xe/CT measurement of LCBF in the MCA contralateral to a deficit was significantly less than in territories without corresponding clinical deficits (P = 0.01), whereas peak systolic velocities in the MCA were not significantly different (P = 0.71). Territories with increases in blood velocity in the MCA of > 50 cm/s/24 h did not have statistically different LCBF (P = 0.183). Our results suggest that increased blood velocity revealed by TCD ultrasonography correlates with increased LCBF and not with ischemia. No difference in LCBF was found in territories with and without rapid increases in blood velocity in the MCA. Furthermore, although focal neurological deficits corresponded with decreased contralateral LCBF in the MCA, increased velocity did not correlate with neurological findings. Therapeutic decisions based solely on blood velocity revealed by TCD ultrasonography might be inappropriate and potentially harmful. Xe/CT studies of LCBF are useful in guiding the management of SAH.

Aneurysm, Ruptured↗
PubMed1995

Surgical management of the cloverleaf skull deformity.

The cloverleaf skull deformity, or Kleeblattschädel, is a rare malformation caused by synostosis of multiple cranial sutures. This anomaly has been reported to carry a dismal prognosis both in terms of neurological outcome as well as cosmetic appearance if treatment is delayed. Due to the paucity of data concerning the results of early operative intervention, it remains uncertain whether aggressive craniofacial decompressive/reconstructive procedures are effective in ameliorating the effects of the malformation on both neurological development and cosmetic appearance. This paper reports the treatment and outcome of 7 children with the cloverleaf skull malformation treated at our institution between 1981 and 1993. All children underwent an initial decompressive craniectomy with the removal of at least 50% of the cranial vault for relief of high intracranial pressure in early infancy. Our first 4 patients underwent near total calvariectomy whereas the 3 children treated subsequently have undergone a staged approach with anterior followed by posterior craniectomies with bone morcellation and replacement. Subsequent reconstructions, intended to further improve the cosmetic appearance, were performed later in infancy or in early childhood. Follow-up ranges from 17 months to 9 years, with a mean of 61 months. Long-term results are reported with regard to neurological outcome as well as normalization of skull shape in terms of both the cephalic indices and general cosmetic appearance. Of the 4 children initially treated with total calvariectomy, only 1 child is neurologically normal and has a good cosmetic appearance. One child is severely impaired neurologically following a sagittal sinus thrombosis suffered during a secondary reconstructive procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Cephalometry↗
PubMed1995

Microvascular decompression for glossopharyngeal neuralgia.

Glossopharyngeal neuralgia is an uncommon cause of facial pain with a relative frequency of 0.2 to 1.3% when compared with trigeminal neuralgia. It is characterized by intermittent, lancinating pain involving the posterior tongue and pharynx, often with radiation to deep ear structures. Since its first description in 1910 by Weisenburg, a variety of destructive procedures have been performed to provide relief in patients whose pain was refractory to medical treatment. These procedures all necessitated the sacrifice of the glossopharyngeal nerve and, in most cases, also involved the destruction of at least part of the vagus nerve as well. In 1977, Laha and Jannetta reported good results in four patients who underwent microvascular decompression of the glossopharyngeal and vagus nerves for glossopharyngeal neuralgia. Since 1971, 40 patients have undergone microvascular decompression of the glossopharyngeal and vagus nerves for treatment of typical glossopharyngeal neuralgia. This procedure provided excellent immediate results (complete or > 95% relief of pain) in 79%, with an additional 10% having a substantial (> 50%) reduction in pain. Long-term follow-up (mean, 48 mo; range, 6-170 mo) reveals excellent results (complete or > 95% reduction in pain without any medication) in 76% of the patients and substantial improvement in an additional 16%. There were two deaths at surgery (5%) both occurring early in the series as the result of hemodynamic lability causing intracranial hemorrhage. Three patients (8%) suffered permanent 9th nerve palsy. (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Isolated toxoplasmosis of the thoracic spinal cord in a patient with acquired immunodeficiency syndrome. Case report.

Toxoplasmosis and lymphoma are the two most common causes of intraparenchymal cerebral mass lesions in patients with acquired immunodeficiency syndrome (AIDS). The clinical and radiographic features of the intracranial lesions have been well described. Because of the high frequency of toxoplasmosis in the AIDS population, common therapy for patients presenting with intracranial mass lesions consists of an empirical trial of anti-Toxoplasma chemotherapy, with biopsy reserved for cases demonstrating features considered to be more consistent with lymphoma, or for lesions that do not improve despite adequate anti-Toxoplasma treatment. A similar treatment algorithm does not exist for intramedullary lesions of the spinal cord. The authors describe a patient who presented with paraparesis resulting from an isolated thoracic intramedullary lesion. An open biopsy of the lesion revealed characteristic structures containing Toxoplasma tachyzoites. The clinical and radiographic presentation of the lesion is discussed, the available literature is reviewed, and a treatment strategy for spinal cord lesions in AIDS patients is proposed.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The effect of hypothermia on the incidence of delayed traumatic intracerebral hemorrhage.

Hypothermia has been shown to cause coagulation abnormalities, primarily related to platelet dysfunction. We reviewed coagulation function and the incidence of delayed traumatic intracerebral hemorrhage in a series of 36 patients with severe head injuries (Glasgow Coma Scale 3-7) enrolled in a prospective, randomized, clinical trial of therapeutic moderate hypothermia. Patients were randomized to a normothermic group (n = 16) or to a group cooled to 32 to 33 degrees C within 6 hours of injury (n = 20). Prothrombin times, partial thromboplastin times, and platelet counts were obtained in the emergency room and then again within 24 hours of randomization. Delayed traumatic intracerebral hemorrhage occurred in 6 of 20 (30%) hypothermic patients and 5 of 16 (31%) normothermic patients. In the hypothermic group, 9 of 17 patients had an increased prothrombin time during hypothermic therapy, as opposed to 11 of 16 in the normothermic group during the corresponding time period. The partial thromboplastin time was prolonged in 2 of 17 hypothermic patients and 2 of 16 normothermic patients. Three patients in the hypothermic group and one in the normothermic group developed thrombocytopenia (a platelet count of less than 100,000). There were no significant differences between the two groups in the incidence of delayed traumatic intracerebral hemorrhage, in measured coagulopathy, or in the mean values of measured coagulation parameters. Although the possibility of a hypothermia-induced coagulopathy has not yet been excluded, the short-term use of hypothermia does not appear to increase the risk for intracranial hemorrhagic complications in head injuries.

Adolescent↗
PubMed1993

Delayed pulmonary perforation. A rare complication of tube thoracostomy.

Tube thoracostomy is a standard therapy for a number of pulmonary disorders. The procedure is associated with a certain incidence of morbidity related to the technique of insertion, the patient population selected, and the length of time the tube remains in place. Complications of tube placement previously described include empyema, residual pneumothorax, lung perforation, placement of the tube in the chest wall, diaphragmatic perforation, perforation of intraabdominal organs (such as spleen, liver and stomach), unilateral pulmonary edema, bronchopleural fistula, hemothorax, cardiogenic shock and Horner syndrome. A case of a delayed pulmonary perforation developing several days after placement of a chest tube is described with a discussion of the clinical and radiographic findings associated with this complication. A possible pathophysiologic mechanism by which this complication may have occurred is proposed.

Aged↗