Neurophysiologic assessment of urinary dysfunction in children with thoracic syringomyelia

Isolated syringomyelia of the thoracic portion of the spinal cord is relatively uncommon. In children, signs and symptoms may involve only the urinary system. Five children who presented for evaluation of urinary tract dysfunction were found to have syringomyelia of the thoracic cord not associated with any other central nervous system abnormality on radiographic imaging. Each child underwent a complete neurologic examination and a complete electrophysiologic/urodynamic evaluation. One patient underwent surgical drainage of the syrinx due to progression of neurologic deficit, with slight improvement; three patients were treated pharmacologically to control the urinary dysfunction.

Nonrandom chromosomal gains in pilocytic astrocytomas of childhood

Low-grade astrocytomas are the most common central nervous system (CNS) tumor occurring in the pediatric age group. Although many of these tumors are karyotypically normal, various studies have reported gains of chromosomes in a significant proportion of cases. We have the opportunity to karyotype two pilocytic astrocytomas occurring in 5- and 15-year-old children. These tumors were characterized by stemlines of 49,XY,+4,+7,+8 and 48,XX,+7,+8. Using these patients as index cases and based on additional karyotypic data that have been published, we performed fluorescence in situ hybridization on 25 additional cases of low-grade astrocytomas in children using pericentromeric probes for chromosomes 4, 6, 7, 8, 9, 10, 11, 12, 15, and 17. Six of 18 (excluding the two index cases), or one third, of the pilocytic astrocytomas were characterized by chromosomal gains, most commonly chromosomes 7 and 8, suggesting that trisomy 7 and 8 are relatively common events in the tumorigenesis of pilocytic astrocytomas. In contrast, chromosomal trisomies were not detected in seven well-differentiated fibrillary astrocytomas with any of the probes chosen.

Nitrous oxide depresses the H-reflex in children with cerebral palsy

Hoffmann's reflex or H-reflex (HR) is an electrically elicited reflex that measures excitability of motoneurons and shares some physiologic properties with the deep tendon reflex. Children with tendon hyperreflexia due to cerebral palsy usually have higher amplitude HRs. Nitrous oxide (N2O) depresses the HR in patients with normal spinal reflexes, although the effect of N2O in conditions with hyperreflexia such as cerebral palsy is not known. We propose to determine the effect of N2O on the amplitude of the HR under general anesthesia in children with hyperreflexia due to cerebral palsy. We studied eight children undergoing selective dorsal rhizotomy (SDR) for the relief of spasticity. The maximum amplitudes of the HR (HRmax) and direct motor response (MRmax) were routinely evoked under the following anesthetic conditions: 1) sufentanil and 66% N2O/33% oxygen; and 2) sufentanil and 100% oxygen. The HRmax amplitude was significantly lower when N2O was part of the inspired gas mixture. The differences between the no N2O and the 66% N2O groups were significant. The MRmax did not change significantly. Abnormal spinal reflexes seen in spastic diplegia can be abolished by inhaled N2O. This finding also suggests that N2O-induced depression of spinal reflexes should be a consideration during physiologic monitoring of the spinal cord under general anesthesia.

De novo Chiari-I malformation in infants demonstrated by sequential magnetic resonance imaging scans. Report of two cases

In this report we demonstrate the de novo development of Chiari-I malformation with hydrosyringomyelia in 2 toddlers on serial brain magnetic resonance imaging scans. We speculate that a mismatch in bony and neural development is the underlying mechanism of these de novo Chiari malformations.

Pial synangiosis for moyamoya syndrome in children

The authors describe a modification of the encephalo-duro-arterio-synangiosis (EDAS) surgical technique for patients with moyamoya syndrome in which the arachnoid is widely opened over the exposed brain and the donor superficial temporal artery adventitia is sutured directly to the pia with 10-O nylon suture ('pial synangiosis'). The procedure has been performed in 34 patients over a 10-year period, with follow-up arteriograms 1 year following the procedure demonstrating markedly enhanced middle cerebral artery flow through the surgical site. Operative morbidity has been limited to two postoperative strokes, both in patients who were neurologically unstable preoperatively; and the clinical stability of the operated patients has thus far been excellent.

Stereotactic radiotherapy for pediatric and adult brain tumors: preliminary report

PURPOSE

Stereotactic radiotherapy is a new modality that combines the accurate focal dose delivery of stereotactic radiosurgery with the biological advantages of conventional radiotherapy (1.8-2.0 Gy/day using 25-30 fractions). The modality requires sophisticated treatment planning, dedicated high-energy linear accelerator, and relocatable immobilization devices. We report here our early experience using stereotactic radiotherapy for intracranial neoplasms.

METHODS AND MATERIALS

Between June 1992 and September 1993, we treated 82 patients with central nervous system lesions using stereotactic radiotherapy, delivered from a dedicated 6 MV stereotactic linear accelerator. A head fixation frame provided daily relocatable setup using a dental plate for all patients over 8 years of age. A modified head frame, which does not require a mouthpiece, was used for children requiring anesthesia. The patients ranged in age from 9 months to 76 years. Thirty-three patients were children less than 21 years of age. Selection criteria for the protocol included: (a) focal, small (< 5 cm) radiographically distinct lesions known to be radiocurable (pituitary adenoma, craniopharyngioma, meningioma, acoustic neuroma, pilocytic astrocytoma, retinoblastoma), and (b) lesions located in regions not amenable to surgery or radiosurgery such as the brain stem or chiasm. Standard fractionation and conventional doses were delivered. Patients with low-grade astrocytoma, oligodendroglioma, or ependymoma were treated using a dose escalation regime consisting of conventional doses plus a 10% increase.

RESULTS

Although follow-up is 16 months (range 3-16 months), posttreatment radiographic studies in 77 patients have been consistent with changes similar to those found after conventional radiation therapy. To date, reduction of up to 50% of the original volume has been noted in 19 out of 77 patients, and 4 patients had a complete response, 2 with dysgerminoma, and 1 each with astrocytoma and retinoblastoma. In 56 patients disease was either stable or the follow-up was too short for evaluation. While the follow-up is relatively short, there have been no in-field or marginal recurrences. The only unexpected radiographic findings were in three patients with pilocytic astrocytomas, who developed asymptomatic edema in the treatment volume. Accuracy in daily fractionation was excellent. In over 2000 patient setups with 41,000 scalp measurements, reproducibility was found to be within 0.41 mm (median) of baseline readings, allowing for precise immobilization throughout the treatment course. The treatment in all cases was well tolerated with minimal acute effects. Our stereotactic radiotherapy facility can provide fractionated therapy for 10-12 patients a day efficiently and accurately.

CONCLUSIONS

The treatment and relocatable stereotactic head frames were well tolerated with minimal acute effects. No long-term sequelae have been noted, although the observation period is short. To fully define the role of stereotactic radiotherapy, we are conducting prospective studies to evaluate neurocognitive and neuroendocrine effects. We expect that this innovative approach will make a significant impact on the treatment of intracranial neoplasms, particularly in children.

A framework for the evaluation of vaccines for use in the expanded programme on immunization

Since 1974, the Expanded Programme on Immunization (EPI) has provided technical support for the immunization of the world's children and women of childbearing age. Today, the vast majority of vaccines administered to these groups are delivered through the immunization programmes that have been established in developing countries. As these national programmes share many characteristics, the global use of a new or improved vaccine could be largely dependent on its compatibility with the priorities, existing antigens and vaccine delivery system of this network. Consequently, a framework has been developed for the systematic evaluation of candidate vaccines for use in EPI.

Microvessel count and cerebrospinal fluid basic fibroblast growth factor in children with brain tumours

Tumour growth is angiogenesis-dependent; brain tumours have more intense neovascularisation than other tumours and produce basic fibroblast growth factor, a potent angiogenic mediator. Because little is known about the release of basic fibroblast growth factor from brain tumours into extracellular fluids, we tested cerebrospinal fluid (CSF) from 26 children and young adults with brain tumours and 18 controls for basic fibroblast growth factor and for proliferative activity on cultured capillary endothelial cells. We also measured the density of microvessels in tumours by immunohistochemical staining. Basic fibroblast growth factor was detected in the CSF of 62% (16 of 26) patients with brain tumours but in none of the controls. Specimens with basic fibroblast growth factor stimulated DNA synthesis of capillary endothelial cells in vitro. Endothelial proliferative activity was blocked by neutralising antibodies to basic fibroblast growth factor. Basic fibroblast growth factor correlated with mitogenic activity in CSF in vitro (p < or = 0.0001), and with density of microvessels in histological sections (p < or = 0.005). A microvessel count of > or = 68 per 200 x field was associated with tumour recurrence (p = 0.005) and with mortality (p = 0.02). Basic fibroblast growth factor in brain tumours may mediate angiogenesis as measured by microvessel density in histological sections, so has potential as both a marker for neoplasia and a target for tumour treatments. Furthermore, evaluation of cerebrospinal fluid basic fibroblast growth factor, along with microvessel quantitation in biopsied tumours, may provide improved prognostic information for the management of patients with brain tumours.

Doppler sensor placement during neurosurgical procedures for children in the prone position

Precordial ultrasonic Doppler devices are effective monitors for detecting venous air emboli (VAE). However, placing an ultrasonic probe on the anterior part of the chest of a prone patient can lead to dislodgment or pressure sores and makes the probe inaccessible to the anesthesiologist. The purpose of this study was to compare placement of a Doppler probe on the patient's back with the traditional precordial site for the ability to detect VAE. We enrolled infants and children undergoing neurosurgical procedures in the prone position in the study. After establishment of general anesthesia and endotracheal intubation, we applied an ultrasonic Doppler probe to the right sternal border of the patient's chest. Anterior insonation was performed with the patient in the supine position. Saline was rapidly injected to verify the efficacy of the monitor (injection test). The patient was turned to the prone position and we placed the Doppler probe between the right scapula and spine. Posterior insonation with saline injection was performed with the patient in the prone position. We obtained positive tests in all patients from the anterior site. Positive tests were obtained from the posterior site in 23 of 24 (96%) children < 10 kilograms (group I), 28 of 39 (72%) children between 10 and 20 kg (group II), and 6 of 22 (27%) children > 20 kilograms (group III). This study demonstrates that a posterior Doppler probe can be effective for monitoring infants at risk of VAE. However, this method is not reliable in children weighting > 10 kg.

H reflex studies in cerebral palsy patients undergoing partial dorsal rhizotomy

H reflex studies were performed in ten spastic children with cerebral palsy who underwent partial dorsal rhizotomy (PDR). Under anesthesia prior to PDR, H reflex amplitude evoked by percutaneous peripheral nerve stimulation gradually declined in all patients and became unobtainable in five. Motor responses could still be evoked by apparent dorsal root stimulation in these five, but since it was shown that they were M responses and not reflexes, PDR was performed randomly. In the other five patients, in whom H reflexes were still evokable, dorsal root stimulation evoked motor responses which were true reflex responses, and PDR was performed "selectively." Compared to preoperative values, postoperative Hmax/Mmax ratios declined, but no more so in selective than in random PDR. We conclude that current intraoperative methods for selection of "abnormal" dorsal rootlets for section may be invalid and may have no bearing on successful outcome, since spasticity improves even with random PDR.

Surgery, radiation, and combination therapy in the treatment of childhood craniopharyngioma--a 20-year experience

The records of 61 children treated for primary craniopharyngioma at the Children's Hospital in Boston and The Joint Center for Radiation Therapy from 1970 to 1990 were reviewed to determine if any information could be obtained regarding the efficacy of surgery versus radiotherapy or a combination of these modalities for this tumor. A select group of 9 children treated without biopsy by radiation therapy alone were all alive without disease progression at follow-up. Although 9 of the 15 children who underwent surgery alone had tumor recurrence, 7 of the 37 children treated with radiotherapy following surgery have also recurred. Treatment morbidity occurred in all groups, but the 10-year actuarial survival for all patients was 91%. Early postoperative imaging and pre- and posttreatment endocrine and neuropsychologic evaluations need to be carried out in all prospective studies of the treatment of craniopharyngioma in children.

Seizures in children with supratentorial astroglial neoplasms

We reviewed the records of 98 consecutive patients, 18 years of age or younger, with pathologically confirmed supratentorial astroglial neoplasms at the Children's Hospital, Boston, to evaluate the importance of seizures in their presentation and natural history. Tumors were diagnosed using the WHO criteria as pilocytic astrocytomas, astrocytomas, anaplastic astrocytomas, glioblastomas, giant cell glioblastomas, oligoastrocytomas and gangliogliomas. Our results were as follows. (1) Fifty percent of children had seizures as part of their presentation and 30% had seizures as their only presenting phenomenon. (2) The seizures varied in nature, but complex (55%) or simple (28%) partial seizures were by far the most common types, occurring in 77% of cases. (3) Preoperative electroencephalography (EEG) accurately lateralized to the tumor side in 88% of the cases and localized to the correct lobe in 56%. (4) Tumors involving cerebral cortex significantly correlated with seizures at presentation as compared to noncortical locations; 59% of patients with cortical tumors presented with seizures, and only 15% of patients with noncortical tumors experienced seizures. Lesions in the temporal and frontal lobes had the highest incidence of seizures. (5) Patients with gangliogliomas and oligoastrocytomas had the highest incidence of seizures, 88 and 86%, respectively, whereas patients with anaplastic astrocytoma had the lowest incidence, 21%. (6) Histopathologic calcification was associated with seizures at presentation approaching significance (p = 0.06). (7) Seizures at presentation were significantly associated with good prognosis (p = 0.02).

Advances in radiation therapy for craniopharyngiomas

The overall survival for patients with craniopharyngioma is excellent. However, conventional treatments that include aggressive surgery and standard irradiation have been associated with significant morbidity. Focal radiation treatment with stereotactic radiosurgery has a role in selected cases, but may also be damaging to sensitive normal tissues such as the optic chiasm. Stereotactic radiotherapy (SRT) is a technique that allows for conventionally fractionated radiation under stereotactic guidance. Thus, highly focal and precise radiotherapy is now coupled with fractionation, enabling the treatment of selected tumors with a potentially improved therapeutic index. Dose optimization with SRT for focally discrete tumors should result in equivalent local control and survival compared to patients treated with conventional irradiation. We anticipate a significant decrease in late effects, especially neuropsychological and neuroendocrine sequelae.

The neurosurgical implications of continuous neurourological surveillance of children with myelodysplasia

Between 1979 and 1990, 148 newborns with myelodysplasia were followed with serial urodynamic studies and neurological assessment. Of the patients 59 (40%) exhibited changes in neurological status by age 5 years, of whom 28 (19%) showed signs of deterioration. Most changes occurred before age 2 years. A total of 22 children underwent repeat neurosurgical exploration because of a change in urethral sphincter innervation (17), deterioration of function of the lower extremities (3), or changes on computerized tomography or magnetic resonance imaging (2). Postoperative urodynamic evaluation demonstrated improvement in 11 children, stabilization in 9 and further deterioration in 2. The earlier that a change was detected and secondary surgery was performed, the better the outcome. These findings indicate that the neurological lesion in myelodysplasia is a dynamic disease process requiring continuous neurological, orthopedic and urodynamic surveillance. Early identification and prompt neurosurgical reexploration seem to arrest and even reverse the neurological deterioration that takes place in a substantial number of these children.

20-year experience in childhood craniopharyngioma

PURPOSE

The management of craniopharyngioma is controversial, and surgery alone is frequently advocated. The purpose of this study was to assess the long-term impact of various treatments in childhood craniopharyngioma.

METHODS AND MATERIALS

Sixty-one children < or = 21 years of age at diagnosis were treated for craniopharyngioma at Children's Hospital and the Joint Center for Radiation Therapy in Boston from 1970 to 1990. The median age was 7.5 years (range 10 months-21 years). There were 33 females and 28 males. The median follow-up was 10 years (range 2-20.5 years). Neuroimaging was available for detailed review in 53. Nine children were treated with radiotherapy alone, 15 were treated with surgery alone, and 37 were treated with both surgery and radiotherapy. All patients in the radiotherapy and surgery plus radiotherapy groups were treated with megavoltage radiation with a median dose of 5464 cGy.

RESULTS

All nine of the children treated with radiation therapy alone are alive; none have recurred. Nine of the 15 children treated with surgery alone have recurred (p = 0.007 Fisher exact test). Two are alive with disease, and seven are alive without disease after treatment at relapse with radiation therapy, surgery, or both. Seven of the 37 patients treated with surgery plus radiotherapy have recurred. Three of the seven patients are dead of disease, three patients are alive with disease, and one patient is alive without disease after further treatment. The 10-year actuarial overall survival was 91% for all patients. The 10-year actuarial freedom from progression for the surgery group was 31% compared with 100% for patients treated with radiation therapy only (log rank p = 0.01), and 86% for patients treated with surgery plus radiotherapy at diagnosis (p = 0.001). There were two treatment related deaths, both in the surgery plus radiotherapy group. A higher incidence of visual loss and diabetes insipidus was associated with the use of aggressive surgery. The size of the tumor at presentation correlated with an increased risk of recurrence; 5 of 6 patients with tumors > or = 5 cm experienced recurrences while only 6 of 30 recurred when the tumor was < 5 cm.

CONCLUSIONS

Overall survival in childhood craniopharyngioma is excellent. However, patients treated with surgery alone have a significantly worse freedom from progression when compared to patients treated with surgery and radiation therapy or radiation therapy alone.

Effect of surgical repair on the neurologic function in infants with lipomeningocele

Eighteen children under the age of 1 year underwent surgery for lipomeningocele at our institution between 1983 and 1991. All the patients had neurologic exams and urodynamic studies (UDS) including a cystometrogram and electromyography of the external urethral sphincter pre- and postoperatively. The surgical procedure performed included an untethering of the spinal cord, laser debulking of the lipoma and placement of a dural graft. All the infants presented with a lesion on their back. Two of 10 infants with a normal neurological exam had abnormal UDS preoperatively. Early surgery normalized abnormal preoperative UDS in 5 of 6 (83%) infants with abnormal UDS. Moreover, 3 of 8 (38%) infants with an abnormal neurological exam preoperatively improved after surgery and none worsened. These observations suggest that abnormal urinary tract function in infants with lipomeningocele may be reversible with early prophylactic surgery.

Chiari malformations, syringomyelia, and intramedullary spinal cord tumors

Optimal management of congenital and acquired spinal cord lesions, such as Chiari malformations, syringomyelia, and intramedullary spinal cord tumors, depends on an understanding of the pathogenesis and natural history of these lesions. Magnetic resonance imaging and detailed physiologic investigations are shedding new light on these difficult-to-diagnose entities, and new surgical techniques are aiding in their management.

Thallium-201 versus technetium-99m-MIBI SPECT in evaluation of childhood brain tumors: a within-subject comparison

We previously found that 201TI SPECT is a highly specific agent for detection of metabolic activity of childhood brain tumors. To compare the relative diagnostic accuracy of 201TI and a technetium-based tumor-avid agent, we have obtained SPECT in 19 children using 201TI (37-111 MBq) followed immediately by 99mTc-methoxyisobutylisonitrile (MIBI) (370-740 MBq) intravenously. Moderate to intense focal uptake of both tracers characterized true positive cases (n = 6). Lesion boundaries were better defined by MIBI. Uptake of MIBI by choroid plexus occurred despite pretreatment with potassium perchlorate (6 mg/kg) and complicated interpretation of deep/paraventricular lesions. Preliminary assessment indicated sensitivity approximately 67% (TI and MIBI); specificity approximately 91% (TI); approximately 100% (MIBI). Two tumors (medulloblastoma, dysgerminoma) were TI/MIBI nonavid. Semi-quantitative assessment of tracer uptake was made using a ratio of radioactivity in tumor-containing areas compared to uninvolved brain. Ratio values were (mean +/- s.d.) 7.88 +/- 7.70 (TI) and 27.1 +/- 36.41 (MIBI). The spectrum of tumor avidity is similar for TI and MIBI. Clearer identification of boundaries by MIBI may be an advantage in applications, e.g., radiotherapy port planning.