Robin P. Humphreys

The Tethered Spinal Cord: Its Protean Manifestations, Diagnosis and Surgical Correction

31 children with spina bifida occulta who have presented with back pain, scoliosis, a progressive neurological deficit involving lower limbs or a neurogenic bladder have been found to have a tethered spinal cord. Release of the tethered spinal cord has always relieved pain, frequently occrected a progressive scoliosis, and arrested or improved neurogenic foot deformities as well as neurogenic bladder.

Arteriovenous malformations of the brain in children : a forty year experience

Despite the great capacity for the pediatric brain to recover from stroke, the morbidity and mortality in children who harbor an arteriovenous malformation (AVM) remains high. This study examines the clinical data and management experience with 132 patients with brain AVM from 1949 to 1989. Although the high tendency for a childhood AVM to present with hemorrhage (79%) remained constant for the forty year study period, the associated morbidity and mortality of hemorrhage changed. The mortality rate from hemorrhage for the entire series was 25%, which was reduced from 39% to 16% after the introduction of computed tomography. The mortality from AVM hemorrhage since 1975 was dependent on location; 8 of 14 patients (57%) with a cerebellar AVM died from hemorrhage while only 2 of 44 patients (4.5%) with a cerebral hemisphere AVM died (p less than 0.0001). Sixteen children (12%) presented with a chronic seizure disorder. Surgical excision of the malformation resulted in complete seizure control off anti-convulsant medication in 73% of patients. Although 21% of patients were treated non-operatively (many with terminal poor-grade hemorrhage), 79% had a surgical procedure with total AVM excision achieved in 70 patients (53.1%). Complete AVM resection was followed by a normal neurological outcome in 47 children (67%). Most partial excisions (n = 9) and clipping of feeding arteries (n = 7) were performed in the early years of this study, and did not provide protection from rehemorrhage. Although conservative management has been advocated for selected non-hemorrhagic AVMs, we conclude that essentially all children with an AVM should be treated in order to eliminate the risk of hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of Anaplastic Changes in Low-Grade Astrocytomas of Childhood

The authors present their experience with six children who developed anaplastic astrocytomas after receiving treatment for low-grade astrocytomas. Five children were from a series of 55 children with optic chiasmatic-hypothalamic gliomas who have been studied since 1976. The sixth child initially had a low-grade astrocytoma of the thalamus. The mean age of the children at initial presentation was 5.3 years. Five children were treated with surgery and radiation therapy; one child with a chiasmatic-hypothalamic glioma received radiation therapy alone. The amount of external radiation therapy used in all children was 50-52.5 Gy delivered in standard fractionations over approximately 6 weeks to include the volume of the original tumor plus a margin of 2 cm. The time to anaplastic transformation varied between 2 and 10 years (mean, 6.4 years). At tumor recurrence, the children had seizures or symptoms and signs of raised intracranial pressure. The location of the second tumor in all patients was either at the primary site or within the field of radiation therapy. Five of the six children underwent a second craniotomy and subtotal resection of their malignant gliomas. One child had positive cerebrospinal fluid cytology and multiple intraspinal metastatic tumor nodules detected by magnetic resonance imaging. On histopathological examination, four children had anaplastic astrocytoma, and two had glioblastoma multiforme. Four of the six children have died of their anaplastic astrocytomas (mean time from diagnosis of anaplastic astrocytoma to death, 10 months). Two children underwent chemotherapy and spinal irradiation for their anaplastic astrocytomas, and are currently alive and undergoing treatment. The possible mechanisms by which anaplastic tumors have developed in children treated previously for low-grade astrocytomas is discussed. The data suggest that radiation therapy may have played an integral role in the genesis of anaplastic astrocytomas in these children.

Posterior fossa medulloblastoma in childhood: Treatment results and a proposal for a new staging system

Seventy-two children with posterior fossa medulloblastoma were diagnosed at the Hospital for Sick Children, Toronto, from 1977 to 1987 and treated by standard methods. The 5- and 10-year survival and disease-free survival rates were 71% and 63%, and 64% and 63%, respectively. Total tumor resection, as determined by the surgeon was the most significant favorable prognostic factor. Post-operative meningitis, a residual enhancing mass lesion on the post-operative, pre irradiation CT scan and dissemination to the brain or cord at diagnosis were unfavorable factors. These four easily definable factors were used to define a staging system with prognostic significance. Five-year disease-free survival rates were for Stage I (total resection, no adverse factor) 100%, Stage II (total resection with one or more adverse factor or less than total resection with no other adverse factor) 78%, and Stage III (less than total resection with one or more adverse factor) 18%. Evaluation of treatment results in medulloblastoma requires that these prognostic factors be known.

Combined utility of functional MRI, cortical mapping, and frameless stereotaxy in the resection of lesions in eloquent areas of brain in children.

We studied 16 children with lesions in the eloquent brain to determine if the amalgamation of information from functional magnetic resonance imaging (fMRI), frameless stereotaxy, and direct cortical mapping and recording could facilitate the excision of these lesions while minimizing potential neurological deficits. The mean age of the children was 10 years. Fourteen children presented with seizures. All lesions were located in or near eloquent cerebral cortex. fMRI was successful in all patients in delineating the relationship between the lesion and regions of task-activated cortex. The ISG wand was utilized in all cases for scalp and bone flap placement, and for intraoperative localization of the lesion. Direct cortical stimulation or recording of phase reversals with somatosensory evoked potentials helped delineate the central sulcus and language cortex in patients with lesions near the motor or language cortex. Intraoperative electrocorticography (ECoG) was utilized in all patients who presented with seizures to guide the extent of resection of the epileptiform cortex. Ten children had benign cerebral neoplasms, nine of which were totally resected. The other diagnoses included vascular malformations, Sturge-Weber, tuberous sclerosis, Rasmussens encephalitis, and primitive neuroectodermal tumor. Only 1 patient with a left Rolandic AVM developed a new neurological deficit postoperatively. Thirteen of fourteen patients who presented with seizure disorders were rendered either seizure free or improved in terms of seizure control postoperatively. Follow-up has ranged from 12 to 18 months, with a mean follow-up of 15 months. We conclude that the techniques of fMRI, frameless stereotaxy, direct cortical stimulation and recording can be utilized in sequence to accurately localize intracerebral lesions in eloquent brain, and to reduce the morbidity of resecting these lesions in children.

Optic glioma in children : surveillance, resection, or irradiation ?

Eighty-seven consecutive children with newly diagnosed optic glioma were managed at University of Toronto hospitals 1958-1990. Overall the 10-year survival, relapse-free survival and freedom from second relapse rates were 84%, 68% and 85%. Twenty-seven patients relapsed or progressed, of whom 40% were free of a second relapse 10 years after the first relapse. Fourteen patients had a second relapse. Thirteen are dead. None survived 5 years after second relapse. Patients with anteriorly located tumors (N = 35), which involved the optic nerve, or chiasm and optic nerves, fared better than those with posteriorly located tumors (N = 52) with spread beyond the chiasm, 10-year survival 95% versus 76%, (p = .02), 10-year relapse-free survival 80% versus 59% (p = .02), respectively. For posterior tumors primary irradiation was more effective than primary subtotal resection for prevention of subsequent relapse, 10-year relapse-free survival 75% versus 41% (p = .02), but salvage therapy was, in part, successful and multivariate analysis of prognostic factors influencing survival for posterior tumors indicated that neither primary resection nor primary irradiation were significant factors. For first relapse, primary irradiation and the presence of neurofibromatosis were the significant favorable factors. Since 1977 and for posterior optic glioma subtotal resection or surveillance were used in 21/29 (72%) patients compared with 4/23 (17%) previously. Ten-year survival rates before and after 1977 were 78% and 67% and 10-year relapse-free survival 64% and 56%, respectively.

Supratentorial primitive neuroectodermal tumors in children.

A retrospective review of 36 children diagnosed with a supratentorial primitive neuroectodermal tumor (PNET) at the Hospital for Sick Children was performed for the period 1970-1995. All children but one received their initial treatment at our institution. There were 18 males and 18 females and the median age at diagnosis was 35 months. Twenty-two PNETs were lobar, 3 were deep in the hemisphere, and 10 were located in the pineal region. One child presented with intracranial leptomeningeal disseminated disease. The tumors were mostly undifferentiated although 22 had some evidence of differentiation along one or more neuroepithelial lines. Five children had a biopsy, 24 had subtotal resection, and 7 had gross total resection. Twenty-six children had adjuvant radiotherapy and 13 had chemotherapy. At last follow-up 30 patients were dead and 6 were alive. The median survival was 23 months and the 2, 3, and 5 year survivals were 50%, 34%, and 18% respectively. All of the survivors received craniospinal radiation and 4 received chemotherapy. There was a statistically significantly worse survival in young children. There was a trend to better survival in children treated since 1984, and in children undergoing gross total resection. Because of the extremely poor survival, we recommended that all children undergo gross total resection followed by chemotherapy. For children older than 3 years of age craniospinal radiation should also be given.

Optic pathway/hypothalamic gliomas : A dilemma in management

Optic pathway gliomas follow an unpredictable course. Some remain static for years; others increase rapidly in size and often lead to death. This unpredictability, along with the histological similarity of these tumors, has resulted in controversy about their management. We have reviewed the results of management of all 62 patients with a diagnosis of optic pathway/hypothalamic glioma treated at The Hospital for Sick Children during the years 1976-1990. Twelve patients received no direct treatment, and 3 only a biopsy. Six patients were treated with radiotherapy alone. Eight patients received radiotherapy following a biopsy. Seventeen patients were treated by resection alone and 16 had a resection followed by radiotherapy. Eight patients received chemotherapy in addition to other therapy, and in 5 of them the chemotherapy was given as an initial therapy. Forty-eight patients are well with their visual deficits but 7 of them are receiving hormone replacement therapy. Six patients have significant neurologic deficits and 8 have died.

Choices in the 1990s for the management of pediatric cerebral arteriovenous malformations

A retrospective 45-year analysis of the management of 160 children with intracranial arteriovenous malformations at The Hospital for Sick Children, Toronto, reveals substantially improving outcomes which relate to more efficient diagnoses and treatments. 80% of children will declare their malformation by means of spontaneous intracranial hemorrhage. For those children who present with hemorrhage or epilepsy, 80% will require an operation. The overall mortality rate has declined to 12% since 1975 and that for the cerebellar lesions from 67 to 42%. 53% of the patients operated upon will be neurologically normal. Endovascular embolization of a childs AVM is a customized, partial solution for a limited number of children. Stereotactic radiosurgery will be used increasingly to obliterate those small lesions in children which are unassociated with hemorrhage or are the residua of an operation. As many as 10% of children (15/160) with diagnosed AVMs cannot be helped with operative or other interventional therapies. The recognition of the pediatric stroke syndromes, the early triage and diagnosis of a childs cerebral hemorrhage, the operative and anaesthetic technologies and the adjunct therapies - choices of the nineties - have resulted in a 66% decline in the overall mortality from this vascular lesion as well as greater assuredness that for most the lesion can be permanently obliterated.

Experience with Surgical Decompression of the Arnold-Chiari Malformation in Young Infants with Myelomeningocele

Forty-five infants with myelomeningocele in whom hydrocephalus was absent or adequately controlled developed signs and symptoms of the Arnold-Chiari malformation before the age of 3 months. All of them underwent laminectomy and opening of the dura mater for hindbrain decompression. The clinical presentation included swallowing difficulty, apneic episodes, stridor, bronchial aspiration, arm weakness, and opisthotonos. Within 2 weeks of the initial clinical presentation, the neurological status of 14 patients (31%) deteriorated dramatically and culminated in irreversible neurological deficits. In all patients, compression of the brain stem occurred in the spinal canal. A transverse dural band constricting the dural sac at the C-1 level was noted in 41% of the patients, and a mild degree of arachnoidal adhesion was noted in 23%. The lowermost level of the cerebellar tongue or medullary kink was located at C-1 to C-4 in 28 cases and at C-5 to T-1 in 17 cases. Twenty-eight (62%) of the patients were alive and 17 (38%) had died at the last follow-up assessment. All survivors showed improvement of their overall neurological function. Twenty-four made a complete recovery. The majority of deaths were attributed to respiratory failure. Early recognition of symptoms and prompt decompressive laminectomy are essential for successful management of the Arnold-Chiari malformation in infants.