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Biomedical subjects

R Michael Scott

Publications and source records attributed to R Michael Scott.

At least 19 recordsLinked to original sources
PubMed2006

Phase II study of thalidomide and radiation in children with newly diagnosed brain stem gliomas and glioblastoma multiforme.

A phase II study was conducted to assess the efficacy of administering daily thalidomide concomitantly with radiation and continuing for up to 1 year following radiation in children with brain stem gliomas (BSG) or glioblastoma multiforme (GBM). Secondary objectives were to obtain preliminary evidence of biologic activity of thalidomide and to evaluate toxicities from chronic administration of thalidomide in this population. Thirteen patients (2-14 years old) with newly diagnosed BSG (12 patients) or GBM (one patient) were enrolled between July 1999 and June 2000. All patients received focal radiotherapy to a total dose of 5,580 cGy. Thalidomide was administered once daily beginning on the first day of radiation and continued for 12 months or until the patient came off study. The starting dose was 12 mg/kg (rounded down to the nearest 50 mg) and was increased by 20% weekly, if tolerated, to 24 mg/kg or 1,000 mg (whichever was lower). Advanced imaging techniques and urine and serum analysis for anti-angiogenic markers were performed in some patients in an attempt to correlate changes with clinical effect of therapy. No patients completed the planned 12 months of thalidomide therapy and all have since died of disease progression. The median duration of therapy was 5 months (range 2-11 months). Nine patients came off study for progressive disease (PD), three patients due to toxicity and one patient withdrew consent. Several patients on this study required more extended courses of high dose steroids than would have been otherwise expected for this population due to significant peritumoral edema and necrosis. No consistent pattern emerged from the biologic correlative studies from 11 patients. However, advanced imaging with techniques such as MR spectroscopy, MR perfusion and 18-fluorodeoxyglucose positron emission tomography (FDG-PET) were helpful in distinguishing growing tumor from treatment effect and necrosis in some patients. The median time to progression (TTP) was 5 months (range 2-11 months) and the median time to death (TTD) was 9 months (range 5-17 months). In this small patient sample adding thalidomide to radiation did not improve TTP or TTD from historical controls, however, toxicity appeared to be increased.

Adolescent↗
PubMed2006

Everyday cognitive function after craniopharyngioma in childhood.

Despite clinical impressions that cognitive complaints are prominent in patients with a history of craniopharyngioma, formal neuropsychologic documentation is inconsistent. This study assessed everyday cognitive complaints and neuropsychologic test performance to evaluate the prevalence of problems and the relationship of these domains to one another in patients treated for craniopharyngioma in childhood or adolescence. Ten patients treated for craniopharyngioma completed measures of everyday cognitive function (Cognitive Failures Questionnaire, Rivermead Behavioural Memory Test) and a battery of standard neuropsychologic tests. The prevalence of problems was ascertained for each measure. Most patients demonstrated significant deficits in everyday memory (Cognitive Failures Questionnaire, 9/10 patients; Rivermead Behavioural Memory Test, 7/10 patients). Scores were within normal limits, however, for intelligence quotient, achievement, attention, verbal memory, and spatial working memory. Processing speed was slow (5/10 patients). Spatial working memory predicted Cognitive Failures Questionnaire (P < 0.07), as did somatic symptoms from the Beck Depression Inventory (P < 0.01), but these associations appeared independent. Adolescents and young adults with treated craniopharyngioma experience deficits in everyday cognitive functions, many involving memory, that are not easily detected by standard neuropsychologic testing. The extent of self-rated cognitive problems is related to spatial working memory and somatic concerns.

Activities of Daily Living↗
PubMed2006

Transverse myelitis after therapy for primitive neuroectodermal tumors.

Traditional therapy for malignant primitive neuroectodermal tumors in children includes surgery, multi-agent chemotherapy, and radiation. Given the poor prognosis with conventional therapy alone, newer treatment approaches have incorporated high-dose chemotherapy followed by autologous stem cell rescue. Treatment with chemotherapy and radiation is not without unanticipated and unwanted side effects. Specifically, radiation-induced damage to the central nervous system can occur, though the frequency is thought to be acceptably low. This report describes two cases of treatment-related transverse myelitis in patients who received induction chemotherapy and craniospinal irradiation followed by high-dose chemotherapy with autologous stem cell rescue. Other patients treated with a similar strategy but different sequence and timing of treatment did not experience symptoms of myelitis, suggesting that the specific timing of radiation in relationship to the chemotherapy may be of critical importance.

Adolescent↗
PubMed2006

Anesthetic management of pial synangiosis and intracranial hemorrhage with a Fontan circulation.

We report the case of a 11-year-old girl with Moyamoya syndrome, who had undergone staged-repair of tricuspid atresia to a Fontan circulation, scheduled to undergo bilateral pial synangiosis. Surgery for the first hemisphere was complicated by intracranial hemorrhage requiring an emergency craniotomy. The case highlights the importance of understanding Fontan physiology and its interrelationship with the cerebral circulation in the setting of cerebrovascular insufficiency and raised intracranial pressure.

Anesthesia, Intravenous↗
PubMed2006

Summer shunt surgery.

Explore the source record for details and available documents.

Cerebrospinal Fluid Shunts↗
PubMed2005

Craniopharyngioma: a personal (Boston) experience.

BACKGROUND: The author reports his experience with 79 craniopharyngiomas operated since 1988. The review demonstrates that the biological behavior of these tumors is extremely variable, and that surgical management requires resourcefulness, judgement, and flexibility in the operating room. RESULTS: Tumors will recur after total resection (15% in this series) and after subtotal resection and radiation therapy (22%) and adjuvant treatments of all types, and no treatment guarantees a cure. CONCLUSION: The invasiveness of the tumor leads to difficult-to-treat long-term complications, particularly obesity and behavior disturbances. An extremely long-term follow-up of up to 20 years is necessary in many patients in order to determine the ultimate outcome of treatment.

Behavioral Symptoms↗
PubMed2005

Stereotactic radiotherapy for localized low-grade gliomas in children: final results of a prospective trial.

PURPOSE: To evaluate the efficacy of stereotactic radiotherapy (SRT) for small, localized, pediatric brain tumors and to determine the patterns of failure. METHODS AND MATERIALS: A total of 81 patients were enrolled in an institutional review board-approved prospective Dana-Farber Cancer Institute protocol between 1992 and 1998. Of the 81 patients, 50 had low-grade astrocytoma, 23 had residual or recurrent craniopharyngioma, 4 had posterior fossa ependymoma, and 4 had other histologic types. All patients underwent biopsy for diagnosis, with the exception of patients with neurofibromatosis and radiographic evidence of an optic system tumor. The neurocognitive outcome for all patients was also an endpoint of the study and will be reported separately. This report focused on the patients with low-grade gliomas only. Of the 50 patients, 26 were males and 24 females; the median age was 9 years (range, 2-26 years). The indications for treatment of patients with low-grade gliomas were progression during or after chemotherapy or progression after surgery alone. SRT was delivered using a dedicated 6-MV linear accelerator. Immobilization was accomplished with a removable head-frame. CT and MRI fusion was used for treatment planning. The target volume generally included the preoperative tumor plus a 2-mm margin for the planning target volume. The median collimator size was 47.25 mm (range, 30-60 mm). Three to nine arcs were used to deliver a mean total dose of 52.2 Gy in 1.8-Gy daily fractions. RESULTS: With a median follow-up of 6.9 years (range, 0.9-10.2 years), the progression-free survival rate was 82.5% at 5 years and 65% at 8 years. The overall survival was 97.8% at 5 years and 82% at 8 years. Six patients had local progression. Two of the patients with local progression had pathologic progression to anaplastic astrocytoma 3 and 7 years after initial SRT. Five patients, all with optic system/hypothalamic primary tumors, developed central nervous system dissemination 1.0-7.4 years after SRT. One patient developed a presumed radiation-induced primitive neuroectodermal tumor 6 years after initial treatment. Six patients died, three of dissemination, two of progression to higher grade tumors, and one of a secondary radiation-induced tumor. All 6 cases of local progression were within the primary tumor bed at the time of progression and had received the full prescription dose. No marginal failures occurred. CONCLUSION: Stereotactic radiotherapy provides excellent local control for children with small, localized low-grade glial tumors. Marginal failures have not been observed, supporting the use of limited margins to minimize late sequelae using stereotactic immobilization and planning techniques.

Adolescent↗
PubMed2005

Continuous remission of newly diagnosed and relapsed central nervous system atypical teratoid/rhabdoid tumor.

Atypical teratoid/rhabdoid tumors (AT/RT) are highly malignant lesions of childhood that carry a very poor prognosis. AT/RT can occur in the central nervous system (CNS AT/RT) and disease in this location carries an even worse prognosis with a median survival of 7 months. In spite of multiple treatment regimens consisting of maximal surgical resection (including second look surgery), radiation therapy (focal and craniospinal), and multi-agent intravenous, oral and intrathecal chemotherapy, with or without high-dose therapy and stem cell rescue, only seven long-term survivors of CNS AT/RT have been reported, all in patients with newly diagnosed disease. For this reason, many centers now direct such patients, particularly those under 5 years of age, or those with recurrent disease, towards comfort care rather than attempt curative therapy. We now report on four children, two with newly diagnosed CNS AT/RT and two with progressive disease after multi-agent chemotherapy who are long term survivors (median follow-up of 37 months) using a combination of surgery, radiation therapy, and intensive chemotherapy. The chemotherapy component was modified from the Intergroup Rhabdomyosarcoma Study Group (IRS III) parameningeal protocol as three of the seven reported survivors in the literature were treated using this type of therapy. Our four patients, when added to the three reported survivors in the literature using this approach, suggest that patients provided this aggressive therapy can significantly alter the course of their disease. More importantly, we report on the first two survivors after relapse with multi-agent intravenous and intrathecal chemotherapy treated with this modified regimen.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Surgical management of moyamoya syndrome.

Moyamoya syndrome, a vasculopathy characterized by chronic progressive stenosis at the apices of the intracranial internal carotid arteries, is an increasingly recognized entity which is associated with cerebral ischemia. Diagnosis is made on the basis of clinical and radiographic findings, including a characteristic stenosis of the internal carotid arteries in conjunction with abundant collateral vessel development. Adult moyamoya patients often present with hemorrhage, leading to rapid diagnosis. In contrast, children usually present with transient ischemic attacks or strokes, which may prove more difficult to diagnose because of patient's inadequate verbal and other skills, leading to delayed recognition of the underlying moyamoya. The progression of disease can be slow, with rare, intermittent events, or it can be fulminant, with rapid neurologic decline. However, regardless of the course, it is apparent that moyamoya syndrome, both in terms of arteriopathy and clinical symptoms, inevitably progresses in untreated patients. Surgery is generally recommended for the treatment of patients with recurrent or progressive cerebral ischemic events and associated reduced cerebral perfusion reserve. Many different operative techniques have been described, all with the main goal of preventing further ischemic injury by increasing collateral blood flow to hypoperfused areas of the cortex, using the external carotid circulation as a donor supply. This article discusses the various treatment approaches, with an emphasis on the use of pial synangiosis, a method of indirect revascularization. The use of pial synangiosis is a safe, effective, and durable method of cerebral revascularization in moyamoya syndrome and should be considered as a primary treatment for moyamoya, especially in the pediatric population.

Journal Article↗
PubMed2005

Craniopharyngioma therapy: long-term effects on hypothalamic function.

BACKGROUND: Craniopharyngiomas are the most common intracranial tumor of extraneural origin in childhood. REVIEW SUMMARY: In this review, we discuss the presentation, diagnosis, and treatment of craniopharyngioma. As the survival prognosis of patients with craniopharyngioma is quite optimistic, long-term side effects of both the tumor and its treatment are now better appreciated. Aside from well-recognized hormonal deficiencies and visual deficits related to tumor location, patients are now acknowledged to experience pathologic obesity and deficits of higher cortical function, memory, and behavior. The combination of these deficits can have profoundly detrimental effects on quality of life. CONCLUSIONS: Careful attention to issues related to hormonal balance, visual field defects, cognitive function, and mood disorders is essential to optimize long-term outcome of patients with craniopharyngioma.

Craniopharyngioma↗
PubMed2005

Diencephalic syndrome: a cause of failure to thrive and a model of partial growth hormone resistance.

Diencephalic syndrome is a rare but potentially lethal cause of failure to thrive in infants and young children. The diencephalic syndrome includes clinical characteristics of severe emaciation, normal linear growth, and normal or precocious intellectual development in association with central nervous system tumors. Our group initially described a series of 9 patients with diencephalic syndrome and found a reduced prevalence of emesis, hyperalertness, or hyperactivity compared with previous reports. Also, the tumors were found to be larger, occur at a younger age, and behave more aggressively than similarly located tumors without diencephalic syndrome. We have been able to extend our follow-up of the original patients, as well as describe 2 additional cases. Because the mechanism of the growth and endocrinologic findings in diencephalic syndrome has not been explained, we report on these patients in light of current research on hypothalamic factors that affect growth and weight. This study emphasizes diencephalic syndrome as a model for additional study of growth hormone resistance and metabolic regulation of adiposity.

Astrocytoma↗
PubMed2005

Moyamoya syndrome associated with Down syndrome: outcome after surgical revascularization.

OBJECTIVES: This study was undertaken to describe the clinical, radiologic, and angiographic features of moyamoya syndrome in a surgical series of children and adults with Down syndrome. We wished to define the features of moyamoya syndrome associated with Down syndrome and to determine the results of surgical revascularization among these patients at early and late follow-up times. METHODS: We reviewed the clinical, radiologic, and angiographic records of all patients with moyamoya syndrome associated with Down syndrome, as a subset of a previously reported, consecutive series of patients who underwent cerebral revascularization surgery with a standardized surgical procedure, pial synangiosis, between January 1, 1985, and June 30, 2004. RESULTS: Of 181 patients with moyamoya syndrome from the initial series who were treated surgically during the study period, 16 patients had Down syndrome (10 female patients and 6 male patients). The average age at onset was 9.3 years (range: 1-29 years); the average age at the time of surgery was 9.8 years (range: 2-29 years). Although the presenting symptoms were transient ischemic attacks for 10 patients and strokes for 6 patients, computed tomographic and/or MRI scans demonstrated bilateral infarctions for 9 patients and unilateral infarctions for 6, with only 1 patient having no imaging evidence of a previous stroke. No cases presented with intracerebral hemorrhage. Preoperative angiography showed the presence of bilateral moyamoya syndrome changes for all patients, including posterior circulation involvement for 8 patients. Surgical treatment included pial synangiosis for all patients, although 1 patient underwent a superficial temporal artery-middle cerebral artery bypass in the contralateral hemisphere. Surgical complications included symptomatic subdural hematomas requiring evacuation, at 48 days and 54 days postoperatively (2 cases), seizures (2 cases), and strokes within 30 days after surgery, at 1 day and 7 days postoperatively (2 cases). Late clinical and radiologic follow-up data (average: 67.6 months; range: 6-146 months) demonstrated no worsening in neurologic status for any patient except for 1 patient who developed a seizure disorder with associated chronic hypocalcemia; she was totally dependent at the 10-year follow-up evaluation, despite no evidence of new infarction since her surgery. There was no clinical or radiologic evidence of new infarction for any patient in late follow-up evaluations. Postoperative angiography, conducted 1 year after surgery for 11 patients, revealed radiologic evidence of good to excellent cerebral revascularization in 85% of the surgically treated hemispheres. Patients were maintained on lifetime aspirin therapy. CONCLUSIONS: The clinical, radiologic, and angiographic features of moyamoya syndrome associated with Down syndrome seem comparable to those of primary moyamoya disease. Cerebral revascularization surgery with the pial synangiosis technique seems to confer long-lasting protection against additional strokes in this patient population. The presence of moyamoya syndrome should be considered in the evaluation of patients with Down syndrome who present with transient ischemic attack-like symptoms.

Adolescent↗
PubMed2004

Perioperative management of diabetes insipidus in children [corrected].

Managing children with diabetes insipidus (DI) in the perioperative period is complicated and frequently associated with electrolyte imbalance compounded by over- or underhydration. In this study the authors developed and prospectively evaluated a multidisciplinary approach to the perioperative management of DI with a comparison to 19 historical control children. Eighteen children either with preoperative DI or undergoing neurosurgical operations associated with a high risk for developing postoperative DI were identified and managed using a standardized protocol. In all patients in whom DI occurred during or after surgery, a continuous intravenous infusion of aqueous vasopressin was initiated and titrated until antidiuresis was established. Intravenous fluids were given as normal saline and restricted to two thirds of the estimated maintenance rate plus amounts necessary to replace blood losses and maintain hemodynamic stability. In all children managed in this fashion, perioperative serum sodium concentrations were generally maintained between 130 and 150 mEq/L, and no adverse consequences of this therapy developed. In the 24-hour period evaluated, the mean change in serum sodium concentrations between the historical controls was 17.6 +/- 9.2 mEq/L versus 8.36 +/- 6.43 mEq/L in those children managed by the protocol. Hyponatremia occurred less frequently in the children managed with this protocol compared with historical controls.

Adolescent↗
PubMed2004

Perioperative management of diabetes insipidus in children.

Managing children with diabetes insipidus (DI) in the perioperative period is complicated and frequently associated with electrolyte imbalance compounded by over- or underhydration. In this study the authors developed and prospectively evaluated a multidisciplinary approach to the perioperative management of DI with a comparison to 19 historical control children. Eighteen children either with preoperative DI or undergoing neurosurgical operations associated with a high risk for developing postoperative DI were identified and managed using a standardized protocol. In all patients in whom DI occurred during or after surgery, a continuous intravenous infusion of aqueous vasopressin was initiated and titrated until antidiuresis was established. Intravenous fluids were given as normal saline and restricted to two thirds of the estimated maintenance rate plus amounts necessary to replace blood losses and maintain hemodynamic stability. In all children managed in this fashion, perioperative serum sodium concentrations were generally maintained between 130 and 150 mEq/L, and no adverse consequences of this therapy developed. In the 24-hour period evaluated, the mean change in serum sodium concentrations between the historical controls was 17.6 +/- 9.2 mEq/L versus 8.36 +/- 6.43 mEq/L in those children managed by the protocol. Hyponatremia occurred less frequently in the children managed with this protocol compared with historical controls.

Adolescent↗
PubMed2004

Long-term outcome in children with moyamoya syndrome after cranial revascularization by pial synangiosis.

OBJECT: Moyamoya syndrome, a narrowing of the basal intracranial vessels accompanied by the development of a cloud of collateral "moyamoya" vasculature, causes cerebral ischemia and stroke. This study was undertaken to determine if a standardized neurosurgical revascularization procedure, pial synangiosis, conferred long-term benefit in pediatric patients. METHODS: The authors reviewed the clinical and radiographic records obtained in a consecutive series of patients with moyamoya syndrome. Patients were 21 years of age or younger and underwent surgery performed by a single neurosurgeon during a 17-year period. There were 143 patients (89 females and 54 males). Sixteen patients were Asian. Neurofibromatosis was present in 16 patients, 13 had undergone therapeutic cranial irradiation, and Down syndrome was present in 10. In 66 there was no known predisposing condition. Stroke had occurred in 67.8% of the population and transient ischemic attacks (TIAs) in 43.4% prior to surgery. Within the first 30 days following 271 craniotomies for pial synangiosis, there were 11 episodes of stroke (7.7% per patient; 4% per surgically treated hemisphere) and three severe TIAs. Follow-up evaluation was performed in all but one patient (mean period 5.1 years). In 126 patients followed for more than 1 year, four suffered a late-onset stroke, one suffered a severe reversible TIA without magnetic resonance imaging-documented evidence of stroke, and two experienced persistent TIAs. In 46 patients followed for more than 5 years in whom the major initial presentation was stroke alone, only two late-onset strokes have occurred. Functional status at the time of surgery determined long-term functional status. CONCLUSIONS: Following pial synangiosis, the majority of pediatric patients with moyamoya syndrome stop having strokes and TIAs, and they appear to experience an excellent long-term prognosis.

Adolescent↗
PubMed2003

Primary medulla oblongata germinoma: a case report and review of the literature.

We describe a case of primary intracranial medulla oblongata germinoma in a 16-year-old girl who presented with progressive headache and blurred vision. Magnetic resonance imaging demonstrated a heterogeneous exophytic mass arising from dorsal aspect of medulla oblongata with extension into fourth ventricle. The differential diagnosis for this patient had included ependymoma, exophytic glioma, medulloblastoma and choroid plexus papilloma. After surgical resection and radiation therapy, she remains alive and recurrence-free for 7 years.

Adolescent↗