A neuropsychological outcome study of a child's left pericallosal arteriovenous malformation with occult fornix lesion.

Pericallosal arteriovenous malformations are rarely reported, particularly in children. Moreover, few arteriovenous malformation studies report thorough neuropsychological outcome data for assessing post-surgical functioning. This case report provides a longitudinal study of a boy who initially presented for neuropsychological testing at the age of 8 years and 1 month, following polyvinyl alcohol embolization, two craniotomies and resections and stereotactic radiosurgery for a pericallosal arteriovenous malformation involving nearly all of the corpus callosum. Follow-up magnetic resonance imaging also indicated absence of the left fornix. Functioning has been assessed over 7 years. Neuropsychological measures identified a consistent pattern of verbally mediated cognitive and memory deficits, with relatively spared visual perceptual and visual motor functioning. No evidence of a split-brain syndrome was found. The findings are consistent with insult to dominant hemisphere language and memory systems, provide an interesting example of neurodevelopmental compensation for significant early brain insult, and may provide insight into functions subserved by the fornix.

Incidence of venous air embolism during craniectomy for craniosynostosis repair.

BACKGROUND: Investigations to determine the incidence of venous air embolism in children undergoing craniectomy for craniosynostosis repair have been limited, although venous air embolism has been suspected as the cause of hemodynamic instability and sometimes death. A precordial Doppler ultrasonic probe is an accepted method for detection of venous air embolism and is readily available at most institutions. METHODS: A prospective study was conducted using a precordial Doppler ultrasonic probe in children undergoing craniectomy for craniosynostosis repair. The Doppler signal was continuously monitored intraoperatively for characteristic changes of venous air embolism. A recording was made of the precordial Doppler probe pulses, which was later reviewed by a neuroanesthesiologist, blinded to the intraoperative events. This information was correlated with the intraoperative events and episodes of venous air embolism were graded. RESULTS: Twenty-three patients were enrolled in the study during the 2-yr study period. Nineteen patients (82.6%) demonstrated 64 episodes of venous air embolism; six patients (31.6%) had hypotension associated with venous air embolism. Thirty-two episodes of hypotension were demonstrated in eight patients (34.7%). None of the patients developed cardiovascular collapse. CONCLUSION: The incidence of venous air embolism in our study of 23 children undergoing craniectomy for craniosynostosis was 82.6%. Though most episodes of venous air embolism during craniosynostosis repair are without hemodynamic consequences, the preemptive placement of a precordial Doppler ultrasonic probe is a noninvasive, economic, and safe method for the detection of venous air embolism. Prompt recognition may allow for the early initiation of therapy, thereby decreasing morbidity and mortality rates related to venous air embolism.

Blood loss and transfusion practice in the perioperative management of craniosynostosis repair.

During the past 5 years, the surgical repair for sagittal synostosis has been modified to a more complex and involved procedure. This led to a retrospective evaluation of the current transfusion practice in a large series of craniosynostosis repairs. The charts of 76 patients (81 surgical procedures) undergoing craniosynostosis repair from January 1990 to November 1996 were examined. The calculated volume of blood loss (BL) was determined for each surgical procedure and related to the estimated blood volume (EBV) and acceptable blood loss (ABL). The anesthesiologist's ability to estimate BL was compared with the calculated blood loss (CBL). In most surgical procedures for craniosynostosis, especially in the complex sagittal repairs, CBL was underestimated and exceeded ABL. Packed red blood cell transfusion occurred in 96.3% of the patients and was appropriate for most procedures based on ABL. Thus, transfusion for craniosynostosis repair is almost inevitable, and the preventive preparation of blood on the order of the mean estimated blood loss (EBL) plus 2 SD is appropriate. With the increased complexity of sagittal repair and its performance in a younger population, the cosmetic benefit of surgical repair has major implications for management of blood and fluids.

Preliminary experience with frameless stereotactic radiotherapy.

PURPOSE: To report initial clinical experience with a novel high-precision stereotactic radiotherapy system. METHODS AND MATERIALS: Sixty patients ranging in age from 2 to 82 years received a total of 1426 treatments with the University of Florida frameless stereotactic radiotherapy system. Of the total, 39 (65%) were treated with stereotactic radiotherapy (SRT) alone, and 21 (35%) received SRT as a component of radiotherapy. Pathologic diagnoses included meningiomas (15 patients), low-grade astrocytomas (11 patients), germinomas (9 patients), and craniopharyngiomas (5 patients). The technique was used as means of dose escalation in 11 patients (18%) with aggressive tumors. Treatment reproducibility was measured by comparing bite plate positioning registered by infrared light-emitting diodes (IRLEDs) with the stereotactic radiosurgery reference system, and with measurements from each treatment arc for the 1426 daily treatments (5808 positions). We chose 0.3 mm vector translation error and 0.3 degrees rotation about each axis as the maximum tolerated misalignment before treating each arc. RESULTS: With a mean follow-up of 11 months, 3 patients had recurrence of malignant disease. Acute side effects were minimal. Of 11 patients with low grade astrocytomas, 4 (36%) had cerebral edema and increased enhancement on MR scans in the first year, and 2 required steroids. All had resolution and marked tumor involution on follow-up imaging. Bite plate reproducibility was as follows. Translational errors: anterior-posterior, 0.01 +/- 0.10; lateral, 0.02 +/- 0.07; axial, 0.01 +/- 0.10. Rotational errors (degrees): anterior-posterior, 0.00 +/- 0.03; lateral, 0.00 +/- 0.06; axial, 0.01 +/- 0.04. No patient treatment was delivered beyond the maximum tolerated misalignment. Daily treatment was delivered in approximately 15 min per patient. CONCLUSION: Our initial experience with stereotactic radiotherapy using the infrared camera guidance system was good. Patient selection and treatment strategies are evolving rapidly. Treatment accuracy was the best reported, and the treatment approach was practical.

Medulloblastoma: time-dose relationship based on a 30-year review.

PURPOSE: Time-dose relationships have proven important in many cancer sites. This study evaluates the time factors involved in the successful postoperative radiotherapy of medulloblastoma, based on a 30-year experience in a single institution. METHODS AND MATERIALS: Fifty-three patients with medulloblastoma received postoperative craniospinal radiotherapy with curative intent between 1963 and 1993. Seven patients (13%) underwent biopsy alone, 28 patients (53%) had subtotal excision, and 18 patients (34%) had gross total excision. Eleven patients received adjuvant chemotherapy. The mean posterior fossa dose was 53.1 Gy; most patients received 54.0 Gy (range, 34.3 to 69.6 Gy). For 41 patients receiving once-a-day therapy, the mean dose was 50.6 Gy (range, 34.3 to 56.0 Gy). For 12 patients receiving twice-a-day therapy, the mean dose was 61.8 Gy (range, 52.6 to 69.6 Gy). Minimum follow-up was 2 years, and median follow-up was 10.7 years. Survival, freedom from relapse, and disease control in the posterior fossa were calculated using the Kaplan-Meier method, and multivariate analysis was performed for prognostic factors. Variables related to radiotherapy were examined, including dose to the craniospinal axis, dose to the posterior fossa, fractionation (once-a-day vs. twice-a-day), use of adjuvant chemotherapy, risk group [high (> or =T3b or > or =M1) or low (< or =T3a and M0-MX)], interval between surgery and radiotherapy (excluding patients receiving chemotherapy before radiotherapy), and duration of radiotherapy. RESULTS: At 5 and 10 years, overall survival rates were 68 and 64%, respectively, and freedom-from-relapse rates were 61 and 52%, respectively. Rates of disease control in the posterior fossa at 5 and 10 years were 79 and 68%, respectively. At 5 years, absolute survival rates after biopsy alone, subtotal excision, and gross total excision were 43, 67, and 78%, respectively (p=0.04), and posterior fossa control rates were 27, 89, and 83%, respectively (p=0.004). Duration of the treatment course was the only radiotherapy-related variable with a significant impact on freedom from relapse and posterior fossa control. For patients whose radiation treatment duration was < or =45 days, posterior fossa control was 89% at 5 years, compared with 68% for those treated for >45 days (p=0.01). Duration of treatment also affected freedom from relapse at 5 years: < or =45 days (76%) compared with >45 days (43%), p=0.004. CONCLUSION: Our study demonstrates that if adequate doses are used, then radiotherapy treatment duration will significantly affect the outcome in terms of control of disease in the posterior fossa and freedom from relapse. Fractions of at least 1.75 Gy given once a day, or a twice-a-day regimen should yield optimal local control results.

Retrorectal cyst-hamartomas and sacral dysplasia: MR appearance.

Retrorectal cyst-hamartoma, an uncommon lesion, arises from hindgut embryonic remnants and may be associated with sacral anomalies. Such a lesion is presacral, multicystic, and lined with glandular or transitional epithelium. Malignant transformation of these lesions has been reported. We describe the clinical, pathologic, and imaging findings in an infant.

Ependymoma: results, prognostic factors and treatment recommendations.

PURPOSE: To review the University of Florida experience in treating ependymomas, analyze prognostic factors, and provide treatment recommendations. METHODS AND MATERIALS: Forty-one patients with ependymoma and no metastases outside the central nervous system received postoperative radiotherapy with curative intent between 1966 and 1989. Ten patients had supratentorial lesions, 22 had infratentorial lesions, and 9 had spinal cord lesions. All patients had surgery (stereotactic biopsy, subtotal resection, or gross total resection). Most patients with high-grade lesions received radiotherapy to the craniospinal axis. Low-grade intracranial lesions received more limited treatment. Spinal cord lesions were treated using either partial spine or whole spine fields. RESULTS: Of 32 intracranial tumors, 21 recurred, all at the primary site; no spinal cord tumors recurred. Overall 10-year survival rates were 51% (absolute) and 46% (relapse-free); by tumor site: spinal cord, 100%; infratentorial, 45%; supratentorial, 20% (p = 0.002). On multivariate analysis, tumor site was the only factor that influenced absolute survival (p = 0.0004); other factors evaluated included grade, gender, age, duration of symptoms, resection extent, primary tumor dose, treatment field extent, surgery-to-radiotherapy interval, and days under radiotherapy treatment. CONCLUSIONS: Patients with supratentorial or infratentorial tumors receive irradiation, regardless of grade. Craniospinal-axis fields are used when spinal seeding is radiographically or pathologically evident. Spinal cord tumors are treated using localized fields to the primary site if not completely resected. Failure to control disease at the primary site remains the main impediment to cure.

Primary intracranial germ cell tumors: clinicopathologic review of 32 cases.

Primary intracranial germ cell neoplasms are rare tumors and constitute a heterogeneous group. We have reviewed 32 cases, over a 21-year period, from the University of Florida. The cases include 22 germinomas, 6 mixed germ cell tumors, and 4 teratomas. The clinical presentations in these cases were more closely related to the location of the tumor, that is, pineal or suprasellar, rather than the histologic subtype. Neuroimaging evaluation was useful in distinguishing between germinomas, teratomas, and other mixed germ cell tumors (MGCTs), primarily by evaluation of cystic versus solid lesions (teratoma versus germinoma), contents of cysts (teratoma versus MGCT), and infiltrative nature of the tumors (MGCT), although cytologic-histopathologic confirmation remains necessary. Germinomas responded favorably to radiation therapy with survival periods of over 16 years; MGCTs were treated with combination chemotherapy and radiation, with a markedly poorer prognosis. This study underlines the critical significance of histopathologic evaluation of the tumor in determining therapeutic interventions as well as prognosis.

Neurosurgery for pediatric brain tumors.

Pediatric brain tumors should be treated at multispecialty centers where the pediatric neurosurgeon constitutes a critical component to the team. Pediatric brain tumors are relatively rare, and diagnosis is often delayed because of the protean manifestations of these tumors clinically. The tumors can occur anywhere along the neuraxis but most commonly in the posterior fossa. The neurosurgeon's role in the care of pediatric patients with brain tumors entails establishing an accurate diagnosis, the treatment of hydrocephalus, the radical and total removal of the offending lesions initially, and the establishment of diagnosis at the time of recurrence. Because of rapid advances in neuroradiology, neuro-oncology, and radiation therapy, most brain tumors in childhood can be eliminated with a high chance for cure and minimal morbidity. The neurosurgeon must be technically adept at radical resection of these tumors even in eloquent areas.

Long-term access to cystic brain stem lesions using the Ommaya reservoir: technical case report.

OBJECTIVE AND IMPORTANCE: Unresectable cystic brain stem lesions are often responsible for neurological dysfunction. Stereotactic aspiration of such lesions can lead to clinical improvement, but cyst recurrence is common and multiple aspirations may be necessary. CLINICAL PRESENTATION: Three children with unresectable cystic brain stem lesions were treated at the University of Florida. Two patients initially underwent stereotactic biopsy and cystic aspiration, both improving after cystic decompression. Both patients returned 3 months later with symptomatic cyst recurrences requiring further intervention. Six years after surgical resection of a posterior fossa medulloblastoma, the third patient presented with a dorsal midbrain cyst. INTERVENTION: All three patients had catheters placed into the cyst cavities under stereotactic guidance. A subcutaneous Ommaya reservoir was attached to the existing catheter. In the event of symptomatic cyst recurrence, the Ommaya reservoir can be tapped in an outpatient setting. CONCLUSION: Cystic decompression resulted in clinical improvement in all three children. Multiple aspirations were necessary in two patients for symptomatic cyst recurrences. The Ommaya reservoir allows for cyst aspiration in an outpatient setting and avoids multiple stereotactic manipulations. This system may also be used to instill radioisotopes or it may be converted to a cyst-peritoneal shunt if multiple aspirations fail to achieve cystic control.

Delayed occurrence of cerebellar pleomorphic xanthoastrocytoma after supratentorial pleomorphic xanthoastrocytoma removal. Case report.

The authors report the case of a 36-year-old woman who underwent gross total resection of a right cerebellar pleomorphic xanthoastrocytoma with atypical features. She had undergone surgery 16 years previously for what was thought to be a right frontal glioblastoma multiforme. In retrospect, based on the histopathology and the clinical course, both lesions were considered to represent atypical variants of pleomorphic xanthoastrocytoma. This report examines the histological and clinical characteristics of this posterior fossa lesion, which exhibited histologically malignant features but has run a relatively indolent course.

Myelinoclastic diffuse sclerosis presenting as a mass lesion in a child with Turner's syndrome.

A rare case of myelinoclastic diffuse sclerosis (MDS), occasionally referred to as Schilder's disease, is reported in a child with Turner's syndrome. The child originally presented with a 3-week history of nausea, vomiting and frontal headaches. Magnetic resonance imaging showed a large, contrast-enhancing, right frontal lobe mass which was ultimately resected uneventfully. Complete laboratory investigations and pathological evaluation of the resected specimen verified the case to be MDS. The clinical presentation, laboratory evaluation, imaging characteristics and diagnosis are discussed in this review of the disease. The importance of including demyelinating diseases in the differential diagnosis for newly discovered mass lesions in the pediatric population is underscored by this case.

Percutaneous transcatheter occlusion of coronary artery fistulas using detachable balloons.

Three pediatric patients underwent successful transcatheter coronary artery fistula occlusion using the Debrun system. This latex balloon system offers several advantages over other occlusion systems. First, the balloon delivery and release is controlled. Second, "test occlusions" can be performed that allow simultaneous balloon inflation, coronary cineangiography, and electrocardiographic monitoring. Third, because the balloons are flow-directed, they are easily positioned in properly chosen locations. Finally, the balloons can be constructed to suit the size of the fistula. In this study, two patients received only one balloon; in the other patient two balloons were placed in the same fistula. All fistulas drained into either the right atrium or ventricle and were successfully occluded. After a follow-up period of up to 3 years, no local or systemic reactions to the balloons were recognized. We conclude that detachable balloon occlusion of coronary artery fistulas is a safe, effective alternative to surgical ligation in selected pediatric patients.

Vein of Galen fistulas.

The vein of Galen malformations continue to be challenging lesions for the neurosurgeon. Evolving therapies, including transvenous and transarterial embolotherapies, have dramatically changed our approach to these lesions over the past 5 years. The neurosurgeon remains the physician in charge of the care of these individuals. In neonates suffering from severe progressive cardiac failure, about a 50% survival rate can be expected. Those patients demonstrating significant injury to the central nervous system prior to therapy should probably be excluded from the aggressive treatment category. Low morbidity and mortality can be expected in the infant and older childhood group of patients harboring vein of Galen malformations treated interventionally. The tendency today is toward a combined transvenous transarterial approach to these lesions, no matter which clinical category is treated. Aggressive therapy is indicated in the control of hydrocephalus and seizures before, during, and after treatment. The overall philosophy, especially in the transvenous approach to these lesions, remains the careful and repeated embolization of these lesions in a staged fashion to encourage a graded thrombosis in an attempt to minimize the risk of hemorrhage and injury to the central nervous system. The overall prognosis is difficult to predict at this time, but it would appear to be better than with standard surgical treatment of these lesions. These therapies are evolving, and further improvements in the techniques and outcome are anticipated.

Temporal characteristics of radiosurgical lesions in an animal model.

To characterize the temporal course of radiosurgical lesions, 19 cats were irradiated in an animal linear accelerator radiosurgical device. The animals were followed clinically and, at 3.5, 6, 12, 18, 23, 29, and 63 weeks, were studied with gadolinium-enhanced magnetic resonance (MR) imaging. They were then sacrificed after Evans blue dye perfusion, and gross pathological and histopathological studies were performed. Mild neurological deficits developed between 3.5 and 4.5 weeks, correlating with the onset of mass effect both grossly and radiographically and with the maximum amount of white matter edema on T2-weighted MR imaging and microscopic examination. Clinical improvement occurred within several weeks as these resolved. The lesions were of similar size at all time intervals. Gadolinium-enhanced MR imaging demonstrated lesions with peripheral areas of enhancement and central nonenhancing regions which correlated histologically with areas of vascular proliferation and radiation necrosis, respectively. In the early lesions at 3.5 and 6 weeks, necrosis and edema were predominant. From 12 to 29 weeks, an intermediate stage was observed, with resorption of the necrotic debris as evidenced by progressive cavitation and microglial response and by increased perilesional vascularity. At 63 weeks, resorption was still taking place, but gliosis and diminution of the vascular response were seen.

Granulomatous angiitis of the spinal cord: a case report.

A 12-year-old caucasian boy presented with a thoracic myelopathy. Magnetic resonance T1-weighted images revealed an enhancing lesion infiltrating the lower thoracic spinal cord to the level of the conus. Evaluation of the lesion by open biopsy revealed granulomatous angiitis of the spinal cord. Granulomatous angiitis is a rare vasculitic process that typically involves the brain and, less frequently, the spinal cord. Diagnosis must be established early by histopathological examination so that treatment with corticosteroids and/or cytotoxic agents may be instituted. When left untreated, patients with granulomatous angiitis of the spinal cord have developed fatal intracranial manifestations.

High-dose chemotherapy with marrow reinfusion and hyperfractionated irradiation for children with high-risk brain tumors.

Between November 1990 and March 1993, nine pediatric patients with newly diagnosed brain tumors having a high risk of failure with standard treatment received high-dose thiotepa/cyclophosphamide chemotherapy followed by autologous bone marrow infusion and involved-field hyperfractionated radiation therapy. The presenting diagnoses were brainstem glioma (BSG) [6], parietal mixed high-grade oligodendroglioma-astrocytoma [1], thalamic anaplastic astrocytoma [1], and high-grade parietal glioma [1]. Following chemotherapy there were two partial responses, one minor response, three with stable disease, and one with progressive disease. Responses were not evaluated in two patients who had toxic deaths. Following radiation two patients, one with brainstem glioma and one with anaplastic mixed glioma, achieved complete remission. The overall survival is no better than conventional therapy.

Value of thallium-201 SPECT imaging in childhood brain tumors.

Thallium-201 chloride single photon emission computed tomography (201Tl SPECT) has been proposed as a diagnostic tool in the assessment of patients with brain tumors. We performed SPECT scans coupled with magnetic resonance imaging (MRI) in children with brain tumors to determine the sensitivity and potential value of SPECT in neuro-oncology. Each patient was injected with 2.5-3.0 mCi of thallium chloride, followed by technetium-99m HMPAO (5-15 mCi) to assess cerebral perfusion. 201Tl uptake was imaged with triple-headed SPECT in 20/24 (83%) histologically and anatomically diverse neoplasms with MRI-measurable residual disease, including 13/16 (80%) posterior fossa tumors. 201Tl SPECT demonstrated uptake in tumors with MRI volumes ranging from 0.03 to 60 cm3. 201Tl SPECT imaging was not correlated with the following MRI features: gadolinium enhancement, necrosis, exophytic, unicentric and multicentric. 201Tl uptake was not detectable in patients with tumors of maldevelopmental origin or radionecrosis. It is suggested that 201Tl SPECT is an important imaging adjunct in the assessment of children with brain tumors.