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Cranial bone repair is one of the oldest neurosurgical practices. Reconstructing the natural contours of the skull has challenged the ingenuity of surgeons from antiquity to the present day. Given the continuous improvement of neurosurgical and emergency care over the past century, more patients survive such head injuries, thus necessitating more than ever before a simple, safe, and durable means of correcting skull defects. In response, numerous techniques and materials have been devised as the art of cranioplasty has progressed. Although the goals of cranioplasty remain the same, the evolution of techniques and diversity of materials used serves as testimony to the complexity of this task. This paper highlights the evolution of these materials and techniques, with a particular focus on the implications for managing pediatric calvarial repair and emerging trends within the field.

Object: The authors describe the application of a flexible CO2 laser for corpus callosotomy in children with epilepsy., Methods: This retrospective case series reviews all cases in which pediatric patients underwent a corpus callosotomy performed using the CO2 OmniGuide laser between May 2005 and October 2012. Data were collected from 8 corpus callosotomy procedures in 6 pediatric patients presenting with medically refractory epilepsy marked by drop attacks., Results: Complete corpus callosotomies were performed in 6 patients (3 boys, 3 girls; ages 5-14 years). In 4 patients the complete callosotomy occurred as a single procedure, and in 2 patients an anterior two-thirds callosotomy was performed first. These 2 patients subsequently required a complete callosotomy due to inadequate control of their drop attacks. In all cases there was clean lesioning of the tract with preservation of the ependymal plane and less inadvertent thermal tissue damage due to low penetration of the laser through cerebrospinal fluid. All patients had resolution or improvement of drop attacks after surgery. No complications were encountered, and imaging demonstrated a clean sectioning of callosal fibers with preservation of normal ventricular anatomy., Conclusions: These cases illustrate the use of this device in completing corpus callosotomy in pediatric patients. The low-profile laser fiber tip was well suited for working in the depths of the interhemispheric fissure with minimal brain retraction. The flexible CO2 laser allows a precise callosal lesioning through an interhemispheric approach and is a useful adjunct to be employed in these cases.

Object: Focal hemosiderin deposition (FHD) is commonly observed on brain MRI scans of patients treated for childhood medulloblastoma (MB). The authors sought to determine the clinical significance of FHD and its relationship to patient age, radiation dose, and cognitive outcomes., Methods: A single-institution retrospective study of 93 MB patients at Lucile Packard Children's Hospital at Stanford from 1998 to 2011 identified 41 patients with a negative baseline MRI scan and at least 2 posttreatment MRI scans obtained with T2* gradient recalled echo (GRE). The number and cumulative rate of FHDs detectable by GRE were compared between patients aged 6 years and younger (early age) and aged 7-21 years (late age) at the time of radiotherapy (RT) and between low-dose (1800-2340 cGy) and high-dose (2920-3960 cGy) RT., Results: The median age at MB diagnosis was 7.3 years (range 0.9-21.0 years), the median clinical follow-up period was 5.8 years (range 0.8-13.4 years), and the median 5-year overall survival was 81% ± 7%. Of 30 school-aged children with MB, 21 (70%) required special education, and the median IQ of 10 tested patients was 100 (range 50-118). Thirty-three patients (80%) had FHD after a median latency of 1.9 years (range 0.1-5.9 years). Ninety-four percent (436 of 466) of the lesions arose in the supratentorial region of the brain, whereas 29 (6%) resided in the brainstem or the cerebellum. No spinal lesions were observed on routine spine MRI scans using T2 fast spin echo imaging. The mean cumulative lesion rate per year was 2.23 ± 3.05, and this rate was higher in older children at the time of RT compared with younger children (3.23 vs 0.67 per year, p = 0.002) but did not differ among different RT doses (p = 0.395). A child's IQ or need for special education showed no significant correlation with the rate of lesion development or number of lesions. None of the lesions resulted in symptomatic hemorrhage that required surgical intervention., Conclusions: More FHD was observed in children treated for MB at the older ages than in those treated at the younger ages. There was no significant association of the incidence of FHD with radiation dose or cognitive outcomes, and none of the lesions required surgical intervention.

Object: Pediatric primary spinal cord tumors (PSCTs) are rare, with limited comprehensive data regarding incidence and patterns of diagnosis and treatment. The authors evaluated trends in the diagnosis and treatment of PSCTs using a nationwide database., Methods: The Surveillance, Epidemiology, and End Results (SEER) registry was queried for the years 1975-2007, evaluating clinical patterns in 330 patients 19 years of age or younger in whom a pediatric PSCT had been diagnosed. Histological diagnoses were grouped into pilocytic astrocytoma, other low-grade astrocytoma, ependymoma, and high-grade glioma. Patient demographics, tumor pathology, use of external beam radiation (EBR), and overall survival were analyzed., Results: The incidence of pediatric PSCT was 0.09 case per 100,000 person-years and did not change over time. Males were more commonly affected than females (58% vs 42%, respectively; p < 0.006). Over the last 3 decades, the specific diagnoses of pilocytic astrocytoma and ependymoma increased, whereas the use of EBR decreased (60.6% from 1975 to 1989 vs 31.3% from 1990 to 2007; p < 0.0001). The 5- and 10-year survival rates did not differ between these time periods., Conclusions: While the incidence of pediatric PSCT has not changed over time, the pattern of pathological diagnoses has shifted, and pilocytic astrocytoma and ependymoma have been increasingly diagnosed. The use of EBR over time has declined. Relative survival of patients with low-grade PSCT has remained high regardless of the pathological diagnosis.

Object: Magnetic resonance imaging is commonly used in diagnosis and surveillance for optic pathway glioma (OPG). The authors investigated the role of diffusion tensor (DT) tractography in assessing the location of visual pathway fibers in the presence of tumor., Methods: Data in 10 children with OPG were acquired using a 3T MRI generalized autocalibrating parallel acquisitions DT-echo planar imaging sequence (25 isotropic directions with a b value of 1000 seconds/mm(2), slice thickness 3 mm). Fiber tractography was performed, with seed regions placed within the optic chiasm and bilateral nerves on the coronal plane, including the tumor and surrounding normal-appearing tissue. Tracking was performed with a curvature threshold of 30°., Results: For prechiasmatic lesions, fibers either stopped abruptly at the tumor or traversed abnormally dilated nerve segments. Similar findings were seen with chiasmatic lesions, with an additional arrangement in which fibers diverged around the tumor. For each patient, DT tractography provided additional information about visual fiber arrangement in relation to the tumor that was not evident by using conventional MRI methods. Retrospective reconstruction of visual fibers in 1 patient with new postoperative hemianopia revealed an unexpected superior displacement of the optic tract that might have been helpful information had it been applied to preoperative planning or surgical navigation., Conclusions: Optic pathway DT tractography is feasible in patients with OPG and provides new information about the arrangement of visual fibers in relation to tumors that could be incorporated into surgical navigation for tumor biopsy or debulking procedures.

Object: Intractable epilepsy following successful brain tumor surgery in children may have several underlying causes such as residual tumor, cortical dysplasia, and gliosis. The authors reviewed the cases of children who had previously undergone resection of a brain tumor only to have medically refractory seizures postoperatively., Methods: The authors performed a retrospective case review of 9 children who underwent brain tumor surgery 2-13 years before undergoing a second surgery to try and control their seizures., Results: Eight of 9 children had seizures at the time of tumor presentation. Tumor types included ganglioglioma, dysembryoplastic neuroepithelial tumor, pilocytic astrocytoma, oligodendroglioma, ependymoma, and choroid plexus papilloma. All patients achieved a seizure-free interval before intractable seizures recurred. After the second operation, 3 children were seizure free, 1 only had auras, 2 had rare complex partial seizures, and 3 continued to have relatively frequent seizures, although the frequency and severity were reduced. Seven of 9 patients had pathology showing residual tumor., Conclusions: Epilepsy surgery following earlier brain tumor surgery can provide substantial benefit with reduced seizure number and severity. Despite reassuring brain imaging results, residual tumor was present more often than expected in pathological specimens.

Posterior reversible encephalopathy syndrome (PRES) has been described in pediatric neurooncology patients, although it has not been documented perioperatively in pediatric neurosurgery patients not actively receiving chemotherapy. Recently at the authors' facility, 2 cases of PRES were diagnosed perioperatively in children with brainstem ependymoma. Both patients had presented with hypertension, altered mental status, and seizures and demonstrated MR imaging features consistent with PRES. The patients were treated with antiseizure and antihypertension medications, leading to improvement in both clinical symptoms and neuroimaging findings. These cases are the first to document PRES in perioperative pediatric neurosurgery patients not actively receiving chemotherapy. Both patients had ependymoma involving the brainstem, which may have led to intra- and perioperative hemodynamic instability (including hypertension) and predisposed them to this syndrome. An awareness of PRES in similar scenarios will aid in the prevention, diagnosis, and treatment of pediatric neurosurgery patients with this syndrome.

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder that occurs most commonly in the pediatric population as a result of pathological clonal proliferation of Langerhans cells with subsequent damage and destruction to surrounding tissue. Clinically, LCH presents in a variety of ways, which often results in prolonged time to diagnosis and subsequently poorer outcomes. In this case report, the authors describe an unusually early presentation of multisystem LCH in a patient at birth, which resulted in a 5-month delay to diagnosis and treatment. This patient presented both atypically young and with an uncommon initial manifestation of multisystem disease with multiple soft-tissue swellings rather than early skin involvement. Additionally, this patient had an unusual radiographic appearance with biparietal skull destruction on initial skull radiographs and biparietal soft-tissue lesions on CT resembling cephalohematoma at 3 months of age. The clinical and radiological evaluation, pathology, and treatment strategies are discussed, with particular attention paid to the importance of further workup of atypical nonresolving cephalohematomas to prevent disease progression and poorer outcomes.

This 8-year-old girl presented with a papillary ependymoma in the thoracic spinal cord. Resection was followed by recurrence at the primary site and later in the lumbosacral thecal sac, followed by cerebrospinal fluid dissemination to the brain approximately 5 years after her initial presentation. The tumor showed cytological and immunohistochemical features overlapping those of classic ependymomas and choroid plexus tumors similar to those seen in uncommon supratentorial papillary ependymomas, also known as papillary tumors of the pineal region. The histopathological and clinical courses of this rare spinal papillary ependymoma exhibiting mixed ependymal and choroid plexus-like differentiation are discussed.

The authors describe the case of a 13-year-old boy who presented with an intraventricular hemorrhage caused by a left trigonal arteriovenous malformation. After an initial recovery, the patient experienced complete right-sided paresis on posthemorrhage Day 6. Severe cerebral vasospasm was found on MR angiography and confirmed on conventional cerebral angiography. Intraarterial nicardipine injection and balloon angioplasty were successfully performed with improved vasospasm and subsequent neurological recovery. Cerebral vasospasm should be considered in the differential diagnosis for neurological deterioration following an arteriovenous malformation hemorrhage, and aggressive treatment can be administered to prevent ischemia and further neurological deficits.

Object: Previous investigations of health outcome after spinal surgery for tethered cord syndrome (TCS) have been single-institution studies. The aim of this study was to report inpatient complications and outcomes on a nationwide level., Methods: The Nationwide Inpatient Sample (NIS) was used to identify patients who underwent spinal surgery for TCS in the US between 1993 and 2002. Patients who had a primary diagnosis of TCS (ICD-9 742.59) and also underwent spinal laminectomies were included in this study. Multivariate analysis was performed to analyze the effects of patient and hospital characteristics on variables such as mortality rate, nonfatal complications, LOS, and adverse outcomes in general (defined as death or discharge to an institution rather than home)., Results: The NIS sample included data on 9733 patients with TCS who underwent surgery. The means for mortality rate, complication rate, and LOS, respectively, were 0.0005%, 9.48%, and 5.6 days. Postoperative hemorrhages or hematomas (mean rate 2.3%) were the most common complications reported. Age and complications were the only significant predictors of adverse outcome on multivariate analysis. Patients older than 65 years had a threefold increase in risk of adverse outcome compared with patients 18 to 44 years of age. On average, one postoperative complication led to a 3-day increase in mean LOS and added more than $9000 to hospital charges., Conclusions: This study provides a national perspective on inpatient complications and outcomes after spinal surgery for TCS in the United States. The authors have demonstrated the impact of age, complications, and medical comorbidities on the outcome of surgery for patients with this common disorder.

Object: Stereotactic radiosurgery for arteriovenous malformations (AVMs) is an accepted treatment option, but few reports have been published on the results of this treatment in children. In this study the authors describe a series of pediatric patients with a minimum follow-up duration of 36 months., Methods: From 1991 to 1997, 40 children (26 boys and 14 girls) with AVMs were treated with radiosurgery at the University of California at San Francisco (UCSF). Follow-up information was available for 31 children (20 boys and 11 girls) in whom the median age at initial treatment was 11.2 years (range 3.4-17.5 years). The median follow-up duration was 60 months (range 6-99 months). Sixteen percent of the AVMs were Spetzler-Martin Grade II; 68%, Grade III; 10%, Grade IV; and 6%, Grade V. The mean volume of the AVMs was 5.37 cm3 and the median volume was 1.6 cm3. The mean marginal dose of radiation was 16.7 Gy and the median dose was 18 Gy (range 12-19 Gy). Angiography performed in 26 children confirmed obliteration of the AVM nidus in nine patients (35%), partial response in 16 patients (62%), and no response in one patient (4%). In five patients who refused angiography, magnetic resonance (MR) imaging revealed obliteration in two patients and partial response in three patients, bringing the overall obliteration rate associated with initial radiosurgery to 35%. Logistic regression analysis confirmed a significant correlation between marginal dose prescription and response (p = 0.025); in AVMs that received at least 18 Gy there was a 10-fold increase in the obliteration rate (63%) over AVMs that received a lower dose. Lesions smaller than 3 cm3 were associated with a six-fold increased obliteration rate (53%) over lesions larger than 3 cm3 (8%), but AVM volume was not a statistically significant predictor of response (p = 0.09). Twelve patients have since undergone repeated radiosurgery and are currently being followed up with serial MR imaging studies (in five cases, the AVM is now obliterated). During the follow-up period (1918 patient-months) there were eight hemorrhages in five patients, with a cumulative posttreatment hemorrhage rate of 3.2%/patient/year in the 1st year and a rate of 4.3%/patient/year over the first 3 years. There were two permanent neurological complications (6%) and no deaths in this study., Conclusions: The lower overall obliteration rate reported in this series is most likely due to the larger mean AVM volumes treated at UCSF as well as conservative dose-volume prescriptions delivered to children. Significantly higher obliteration rates were observed when a marginal radiation dose of at least 18 Gy was delivered. The permanent complication rate is low and should encourage those treating children to use doses similar to those used in adults.

Object: In this study the authors report on the results of endovascular treatment for mural-type vein of Galen malformations (VGMs) in a group of infants., Methods: Eight children (six infants and two neonates) who suffered from symptoms caused by a mural-type VGM were treated by means of endovascular therapy. Their age at the time of treatment ranged from 13 days to 19 months (mean 7.6 months). Two neonates and three infants who presented with hydrocephalus and increased head circumference, one of whom was stabilized with a shunt, underwent elective closure of the malformations 3, 4, 6, 6, and 13 months later, respectively. Two patients presented with hemorrhage; one had an intraventricular hemorrhage (IVH) on the 1st day of life and one, a 5-month-old infant, suffered a large parenchymal hemorrhage and an IVH; both patients were immediately cured by means of endovascular techniques. One child presented with a seizure and cortical venous drainage that were treated immediately. Eleven separate treatment sessions were conducted; eight via transarterial femoral access and the remaining three via a transvenous approach. Two patients were treated by using transfemoral transvenous embolization with fibered coils, and one patient required a transtorcular transvenous approach to permit complete closure of the fistula with electrolytically detachable coils. The embolic devices used included silk suture emboli (three patients), electrolytically detachable coils (three patients), and fibered platinum coils (seven patients). In seven patients, complete closure was demonstrated on postembolization arteriographic studies. The eighth patient had stagnant flow in a giant 6-cm varix treated with arterial and venous coils but has not yet undergone follow-up studies. Late follow-up arteriography was performed in four patients at times ranging from 11 to 24 months postprocedure. In one patient, thrombosis of the malformation and shrinkage of the varix were confirmed on follow-up computerized tomography scanning. The remaining three patients have not yet undergone follow-up angiographic examination. Two asymptomatic complications occurred, including separation of the distal catheter, which was removed with a snare device, and a single platinum coil that embolized to the lung, producing no symptoms in 101 months of clinical follow up. The follow-up period ranged from 3 to 105 months, with a mean of 52 months., Conclusions: Endovascular therapy is the treatment of choice for mural-type VGMs and offers a high rate of cure with low morbidity.

The case of a young girl with a pericallosal venous malformation associated with multiple cryptic vascular malformations (CVM's) is described. The presenting cryptic malformation, which hemorrhaged, was completely excised, but the venous malformation was not. Routine follow-up magnetic resonance images obtained over the past 9 years have documented the development of multiple new cryptic malformations along the radicles of the venous malformation. Magnetic resonance imaging and cerebral angiography revealed venous outflow obstruction at the junction of the venous malformation with the straight sinus. The association of CVM's with anomalous venous drainage patterns and the role of venous hypertension in the pathogenesis of cryptic malformations are discussed. This case suggests that CVM's associated with a venous malformation may recur and new ones may develop if the venous malformation is not excised, particularly if venous hypertension is also present. The likelihood of a surgical cure in these patients may depend on complete excision of both anomalies, which is rarely feasible because of the potentially devastating results of resecting a venous malformation. Alternative treatments for patients with both types of lesions are discussed.

Little is known about the risk of developing multicentric disease in patients with juvenile pilocytic astrocytoma (JPA), and even less about its prognosis. Only five cases have been reported. Between 1986 and 1992, the authors treated 90 patients with either primary or recurrent JPA, 11 of whom developed multicentric spread. Ten patients had primary tumors in the hypothalamic region, eight were under 4 years of age at initial diagnosis, all had initially undergone a subtotal resection or biopsy, and 10 received postoperative multiagent chemotherapy or irradiation for residual disease. Multicentric spread was discovered immediately to 108 months after initial diagnosis; nine patients were asymptomatic at the time. Most patients received chemotherapy for the multicentric disease, which was found throughout the craniospinal axis. During 21 to 148 months of follow-up monitoring, seven patients had stabilization or regression of multicentric disease and four died. Patients with hypothalamic region tumors were 23 times more likely to develop multicentric spread than were those with primary tumors located elsewhere (p < 0.001). Based on this review, it is concluded that multicentric spread of JPA occurs more frequently than was previously recognized. In patients with subtotally resected JPA and several years of follow-up review via magnetic resonance imaging, the incidence of recurrence in a site different from the original was 12%. Patients with subtotally resected JPA in the hypothalamic region should be considered to be at high risk for developing multicentric spread. Chemotherapy appears useful in stabilizing multicentric disease. Earlier detection and intervention may result in longer disease-free survival in patients with multicentric spread of JPA.

Meningiomas arising in the first two decades of life are uncommon and their characteristics are controversial. Some authors believe meningiomas in younger patients occur in different locations, have more malignant histological features, and have a worse prognosis than those in adults. To address this controversy, the authors retrospectively reviewed 23 cases of meningiomas in patients under 21 years of age at diagnosis who were operated on at the University of Turin (1948 to 1990) or at the University of California, San Francisco (1970 to 1989). These tumors represented 2.9% of all tumors in this age group and 1.8% of all meningiomas during the study period at the two institutions. There were 14 males and nine females. The mean age at surgery was 13.3 +/- 5.6 years; nine cases occurred in the first decade and 14 in the second. The most common neurological symptoms were a focal neurological deficit (33%) and seizures (25%). Seventy percent of the tumors were supratentorial. A gross total resection was performed in 60% of the cases. Histologically, the majority (74%) of the tumors were meningothelial or mixed. An increased number of mitoses was observed in 33% of the tumors, focal necrosis in 29%, and invasion of adjacent brain in 14%; however, none of the tumors was classified as a Grade III (anaplastic) meningioma. All patients are alive without evidence of recurrent disease 3 to 22 years (mean +/- standard deviation: 10 +/- 7.3 years) after surgery. This study confirms the rarity of meningiomas of the first two decades of life and the absence of the female predominance associated with meningiomas in adults. The location and histological features of these tumors are similar to those in adults; they have a low recurrence rate, and the outcome and survival rate are excellent.

Six children with a history of isolated facial nerve dysfunction or dizziness and nausea were treated for brain-stem glioma between 1984 and 1992. Computerized tomography and/or magnetic resonance (MR) imaging showed a focal, uniformly enhancing mass involving the facial nerve nucleus of the pons. All patients underwent biopsy; the histological diagnosis was juvenile pilocytic astrocytoma in five cases. In the remaining case the biopsy was nondiagnostic, although the surgeon believed that the lesion was a glioma. Postoperatively, five patients underwent conventional focal megavoltage radiation therapy (180 to 200 cGy/day) over a period of 5 1/2 weeks to a total dose of approximately 5400 cGy. One child's family refused radiation therapy; she remained well and stable for 4 years, despite persistent facial weakness, and was eventually lost to follow-up review. Four irradiation-treated patients had complete resolution of their tumors on MR images and have had no evidence of neuropsychological or neuroendocrinological deficits during 4 1/2 to 8 years of follow-up evaluation. Patients whose neuroradiological studies show a lesion resembling those in this series should undergo biopsy and, if the histology of a low-grade tumor (in particular, a juvenile pilocytic astrocytoma) is confirmed, should then receive focal radiation therapy with conventional megavoltage dosages.

The authors report the case of a metastatic juvenile pilocytic astrocytoma of the hypothalamic region in a 10-year-old boy. Eight years after craniotomy and radiation therapy, the tumor spread via cerebrospinal fluid pathways to the left cerebellar tonsil and the lumbosacral region. Histological evaluation of both the original hypothalamic and the new lumbosacral masses showed features of a slow-growing juvenile pilocytic astrocytoma with no evidence of malignant transformation. The clinical implications and possible mechanisms of metastatic spread are discussed.

Between March, 1983, and February, 1989, 19 infants or children with chiasmal/hypothalamic gliomas were treated with chemotherapy after either surgical or radiological diagnosis. The patients ranged in age from 15 weeks to 15.6 years (median 3.2 years) at the start of therapy. Twelve patients were treated immediately after diagnosis because of progressive symptoms, and seven received chemotherapy after either radiographic progression or clinical deterioration, including progressive visual loss or intracranial hypertension. Based on biopsy results, seven of these tumors were classified as juvenile pilocytic astrocytomas, two as astrocytomas, two as highly anaplastic astrocytomas, and one as a subependymal giant-cell astrocytoma. There was associated neurofibromatosis in four patients. The two initial patients were treated with either actinomycin D and vincristine or 5-fluorouracil, hydroxyurea, and 6-thioguanine. The remaining patients received nitrosourea-based therapy; 15 evaluable patients were treated with a five-drug regimen that included 6-thioguanine, procarbazine, dibromodulcitol, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), and vincristine and one received 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 5-fluorouracil. Fifteen of the 18 evaluable patients initially managed with chemotherapy either responded to therapy or their condition stabilized. Median time to tumor progression has not been reached at a median follow-up period of 79 weeks (range 6.6 to 303 weeks), and no tumor-related death has occurred with a median follow-up period of 79 weeks (range 18 to 322 weeks) from the initiation of therapy. The four patients who failed therapy or whose disease progressed after chemotherapy were treated satisfactorily with radiation therapy. Initial improvement or stabilization of visual function was obtained in 16 patients. Endocrine function remained stable in all patients during treatment, although three patients required pharmacological treatment for endocrinopathy that was present at diagnosis. These preliminary results suggest that nitrosourea-based cytotoxic regimens are useful for the initial treatment of children with chiasmal/hypothalamic gliomas, and allow potentially harmful radiation therapy to be deferred until progression of disease.

The best operative intervention for children with arachnoid cysts remains the subject of controversy. Recent reports stress that craniotomy for cyst fenestration is associated with a low incidence of morbidity and mortality and may leave the child shunt-independent. The cases of 40 pediatric patients with arachnoid cysts treated between 1978 and 1989 are reported. Five children with mild symptoms and small cysts that remained stable on follow-up studies have not required surgical intervention. Of 15 patients with cysts initially treated by fenestration, 10 (67%) showed no clinical or radiographic improvement postoperatively and have undergone cyst-peritoneal (eight patients) or ventriculoperitoneal (VP) shunting (one patient), or revision of a VP shunt placed for hydrocephalus before cyst fenestration (one patient). Two other patients with existing VP shunts required no further procedures. Thus, only three (20%) of 15 patients initially treated by fenestration remain shunt-independent after a median follow-up period of 8 years. The 20 other patients were initially treated by cysts shunting and all improved postoperatively; shunt revision has been necessary in six (30%) of these 20 patients because of cysts recurrence. Cyst location influenced the success of shunt treatment; none of the seven middle cranial fossa cysts treated by shunting have required revision, but results with cysts in other locations were less favorable. In all locations, though, shunting was more successful than fenestration. It is concluded that cyst-peritoneal or cyst-VP shunting is the procedure of choice for arachnoid cysts in most locations, including those in the middle cranial fossa.

The cases of seven patients with intramedullary, cryptic vascular malformations of the spinal cord are reported. In all patients, the clinical course was progressive; a Brown-Séquard syndrome was the most common presenting symptom complex. Magnetic resonance (MR) imaging was performed in all patients. The pattern seen most often was a focus of high signal (on both T1- and T2-weighted MR images) surrounded by a larger zone of low signal (best seen on T2-weighted images), and was remarkably similar for all patients. Six patients underwent surgical exploration; removal of the lesions halted the progression of symptoms in five patients, and one patient had worsened sensory function after surgery. Motor function did not decrease postoperatively in any patient. The one patient who refused surgery has continued to decline neurologically. Histopathological examination of surgical specimens showed a cavernous malformation in one patient, a venous malformation in one, venous varices in two, and organizing hematomas in two; these findings are markedly different from those in previously reported cases of cryptic vascular malformations.

Using a CO2 laser, discrete thoracic spinal cord lesions were made in cats anesthetized with ketamine and xylazine (Rompun). Differences in cortical somatosensory evoked potentials (SEP's) produced with high-intensity stimulation (20 times the motor threshold) of each posterior tibial nerve determined for nine different combinations of unilateral spinal cord lesions. The results of these studies show that nerve fibers in the ipsilateral dorsal column, the ipsilateral dorsal spinocerebellar tract, and the contralateral ventrolateral tracts with respect to the side of leg stimulation, contribute to cortical SEP's. A lesion of the dorsal spinocerebellar tract affected only the early waves (less than 30 msec) of the SEP from leg stimulation ipsilateral to the side of the lesion, whereas a solitary lesion of the ventrolateral tract caused changes primarily in the amplitude of later waves (greater than 30 msec) of the SEP produced by contralateral leg stimulation. Lesions involving one-half of the dorsal column caused changes in the amplitude of both the early and late waves produced by stimulation ipsilateral to the side of the lesion. The effects of various combinations of lesions on the cortical SEP's were not additive, which indicates significant interaction between afferent pathways. These findings suggest that high-intensity peripheral nerve stimulation, which activates both C and A fibers, could be used intraoperatively to assess spinal cord function with more accuracy than the current practice of using a stimulus strength of twice the motor threshold. The importance of using anesthetic agents that do not depress cortical activity (which may affect the later components of the SEP) is also emphasized.

Preoperative computerized tomographic (CT) scans of 24 children who had surgery for either single or multiple craniosynostoses were compared with skull radiographs and operative and pathological findings. In addition to providing accurate imaging of calvarial and skull base deformities secondary to premature suture closure, high-resolution CT with bone definition algorithms supplied valuable detail of anatomical changes at the abnormally developed suture. The CT findings varied with the location of the suture. Thickened bony ridges predominated at the sagittal suture, focal bone thickening and erosions were more likely to be found at the metopic suture, and parasutural sclerosis was the prevalent finding on one side of the lambdoid suture. No evidence of the suture could be detected in the majority of patients with complete coronal craniosynostosis. Radiographs of the skull were shown to be a relatively insensitive means of imaging the zone of limited fusion, especially the lambdoid suture. An excellent correlation was found between the CT scan and the operative and pathological findings. There was histological evidence of progressive suture fusion in virtually all patients. An asymmetrically narrowed lucent zone with parasutural sclerosis or bony ridges seen on CT scans correlated well with fibrous union of the suture found on histological examination. The authors conclude that high-definition CT used in conjunction with bone windows and thin and coronal slices for the evaluation of sagittal sutures is a useful imaging method for the evaluation of craniosynostosis.

The authors have conducted a Phase II trial to evaluate orally administered dibromodulcitol in the treatment of 40 evaluable patients with recurrent medulloblastoma, ependymoma, and malignant astrocytoma. Ten of 20 patients harboring medulloblastoma responded to therapy with a median time to tumor progression (MTP) of 40 weeks, and four of 20 patients had no sign of progression of disease 4 years after treatment was begun. The MTP for all 12 patients with ependymoma was 30 weeks. Nine of these 12 patients had stabilization of their disease with an MTP of 67 weeks; three of these 12 patients had no signs of progression for 1 to 3 years after treatment was begun. Of six patients harboring supratentorial gliomas, none responded to dibromodulcitol. Two patients, one with a primitive neuroectodermal tumor and the other with a metastatic carcinoma of the breast, had stabilization of disease for more than 4 and 2 years, respectively.

A digital video fluorescence microscopy technique was used to evaluate the distribution of hematoporphyrin derivative (HPD) in the rat intracerebral 9L gliosarcoma brain-tumor model at 4, 24, 48, and 72 hours after intravenous administration of 10 mg/kg of the drug. Compared to surrounding normal brain, there was significant preferential uptake of HPD into the tumor. In sections surveyed, fluorescence reached a maximum value by 24 hours; however, only 33% to 44% of the tumor was fluorescent. In contrast, fluorescence within the surrounding normal brain was maximum at 4 hours, but was present in less than 1% of the brain tissue evaluated. The effect of HPD sensitization to a laser light dose (633 nm) of 30 joules/sq cm delivered through the intact skull was evaluated histologically in 10 rats. A patchy coagulation necrosis, possibly corresponding to the distribution of HPD fluorescence seen within the tumor, was observed. There was evidence that photoradiation therapy (PRT) affects defective tumor vasculature and that a direct tumor cell toxicity spared normal brain tissue. Despite these findings, limited uptake of HPD in tumor and the brain adjacent to tumor may decrease the effectiveness of PRT in the 9L gliosarcoma brain-tumor model. Because of the similarity between the capillary system of the 9L tumor and human brain tumors, PRT may have a limited therapeutic effect in patients with malignant brain tumors.

The authors reviewed the clinical findings, radiological evaluation, and operative therapy of 39 patients with syringomyelia. Syringoperitoneal (SP) shunting was used in 15 patients and other procedures were used in 24 patients. Follow-up periods ranged from 1 1/2 to 12 years. During the period of this study, metrizamide myelography in conjunction with early and delayed computerized tomography scanning replaced all other diagnostic procedures in patients with syringomyelia. Preoperative accuracy for the two procedures was 87%. The most common symptoms were weakness (79%), sensory loss (67%), pain (38%), and leg stiffness (28%). Surgery was most effective in stabilizing or alleviating pain (100%), sensory loss (81%), and weakness (74%); spasticity, headache, and bowel or bladder dysfunction were less likely to be reversed. Approximately 80% of patients with idiopathic and posttraumatic syringomyelia and 70% of those with arachnoiditis improved or stabilized. Better results were obtained in patients with less severe neurological deficits, suggesting the need for early operative intervention. A higher percentage of patients had neurological improvement with SP shunting than with any other procedure, especially when SP shunting was the first operation performed. Patients treated with SP shunts also had the highest complication rate, most often shunt malfunction. These results indicate that SP shunting is effective in reversing or arresting neurological deterioration in patients with syringomyelia.

Seventeen patients with recurrent medulloblastoma were treated with a combination of three drugs: procarbazine, CCNU, and vincristine (PCV). Tumor recurrence was documented at varying periods following surgery and radiotherapy. Among 16 evaluable patients, ten showed a response to PCV on the basis of subjective neurological improvement and a decrease in tumor size by radiological criteria. Five patients were designated as having stable disease on the basis of no change in neurological status and tumor size. One patient showed uninterrupted progression of disease. The median time to progression for all patients was 45 weeks. Significnat myelotoxicity, exacerbated by prior spinal irradiation, compromised therapy. After an initial response, it was often necessary to reduce the higher doses of CCNU and procarbazine that caused concomitant bone-marrow toxicity; as a consequence of the lowered doses, tumor progression was then frequently observed. The authors conclude that PCV is an effective form of palliative therapy for recurrent medulloblastoma.

Spontaneous thrombosis of aneurysms occurs rarely in children, and, to our knowledge, there are no reports of aneurysms presenting as an embolic event in a child. We describe the case of a 3-year-old boy whose symptoms initially suggested an ischemic event to the dominant hemisphere. Initial computerized tomography scans indicated an intracranial hemorrhage. Subsequent radiographic study revealed evidence of emboli and, at exploration, a large acutely thrombosed aneurysm of the left middle cerebral artery associated with arterial occlusion was found. Entrapment of the aneurysm and thrombectomy provided excellent operative results.

The argon surgical laser has been used in 68 neurosurgical procedures that included the removal of intracranial and intraspinal tumors, spinal cord fenestration for syringomyelia, and the production of dorsal root entry zone lesions. Characteristics that make the argon surgical laser a useful microneurosurgical instrument include the availability of a fiberoptic delivery system, a laser spot size that can be varied continuously between 0.15 and 1.5 mm, a single laser-aiming and treatment beam, the transmission of argon laser light through aqueous media such as irrigating or cerebrospinal fluids, and improved hemostasis compared to conventional techniques. The argon laser is limited primarily by its relatively low power output (less than 16 W), which makes the excision of large tumors difficult. However, even with these limitations, which can be used to advantage in the proper setting, the authors' laboratory and clinical experience suggests that the argon surgical laser may be useful in certain microneurosurgical operations.

Thirty-eight patients undergoing surgical removal of neuroectodermal tumors of the central nervous system were given a 1-hour intravenous infusion of bromodeoxyuridine (BUdR), 150 to 200 mg/sq m, to label tumor cells in the deoxyribonucleic acid (DNA) synthesis phase (S-phase). The excised tumor specimens were divided into two portions: one was fixed with 70% ethanol and embedded in paraffin and the other was digested with an enzyme cocktail to make a single-cell suspension. The paraffin-embedded tissues were stained by an indirect peroxidase method using anti-BUdR monoclonal antibody (MA) as the first antibody. Single-cell suspensions were reacted with fluorescein isothiocyanate (FITC)-conjugated anti-BUdR MA's for flow cytometric analysis. S-phase cells that had incorporated BUdR into their DNA were well stained by both methods. The percentage of BUdR-labeled cells, or S-phase fraction, was calculated in tissue sections by microscopic examination and in single-cell suspensions by flow cytometric analysis. The biological malignancy of the tumors was reflected in the S-phase fractions, which were 5% to 20% for glioblastoma multiforme, medulloblastoma, and highly anaplastic astrocytoma, but less than 1% in most moderately anaplastic astrocytomas, ependymomas, and mixed gliomas. Two juvenile pilocytic astrocytomas and two low-grade astrocytomas from children had high S-phase fraction despite the fairly benign and slow-growing nature of these tumors. These results indicate that the S-phase fraction obtained immunocytochemically with anti-BUdR MA's may provide useful information in estimating the biological malignancy of human central nervous system tumors in situ.

The photo- and radiosensitizing properties of bromodeoxyuridine (BUdR) were assessed in vitro using the 9L rat brain tumor cell line. Pretreatment of 9L cells with 10 microM BUdR for 24 hours followed by irradiation with ultraviolet (UV) light resulted in a dose-enhancement ratio of 3.8:1 compared with UV radiation alone. X-radiation of BUdR-pretreated cells produced a dose-enhancement ratio of 1.7:1. Alkaline elution analysis of deoxyribonucleic acid (DNA) from cells treated with BUdR and UV irradiation showed the presence of DNA single-strand breaks and DNA-protein cross-links. Analysis of DNA from cells treated with BUdR and then x-irradiated showed no increase in DNA single-strand breaks compared with cells treated with x-radiation alone; no DNA-protein cross-links could be detected. The possible clinical relevance of these findings is discussed.

Treatment results for 36 patients with juvenile pilocytic astrocytoma treated from 1942 through 1985 at the University of California, San Francisco, were reviewed. Twenty-two tumors were located in the posterior fossa, 10 were in the hypothalamic region, and four were in the cerebral hemispheres. Twenty-eight patients were less than 18 years of age. The overall survival rate was 83% and 70% at 10 and 20 years, respectively. All 12 patients who had total tumor resection remain disease-free; only two of the 12 received postoperative irradiation. The 10- and 20-year freedom-from-progression for the 19 patients who had incomplete resection and received at least 40 Gy of postoperative irradiation was 74% and 41%, respectively. All patients who failed treatment had local recurrence. One patient developed diffuse meningeal seeding, after four local recurrences in the posterior fossa over a 23-year period. Six patients failed treatment and had a repeat biopsy at the time of recurrence or at postmortem examination, and three showed histological progression of the tumor to an anaplastic astrocytoma. Based on this study and others in the literature, a protocol has been adopted whereby patients who have total tumor resection are not treated with postoperative irradiation. Patients who have incomplete tumor resection and are older than 3 years of age are currently treated with postoperative partial-brain irradiation, to a dose of 45 to 60 Gy. In general, young children with incomplete resection are followed closely with computerized tomography or magnetic resonance imaging and are treated with chemotherapy or irradiation if tumor progression is documented.

Argon and carbon dioxide microsurgical lasers were used to produce lesions in the dorsal root entry zone (DREZ) experimentally in six cats and surgically in 21 patients who had denervation pain syndromes. The technique of producing lesions, the histological and physiological changes seen in the cat spinal cord, and the results of treatment in the clinical series are discussed. Lesions were produced within the DREZ without new involvement of the dorsal column system or corticospinal tract in all but one patient. Based on their subjective evaluation, two-thirds of the patients were relieved of more than 50% of their preoperative pain. These experimental results and clinical experience suggest that the argon and carbon dioxide lasers effectively produce localized microsurgical lesions in the DREZ. The concept that an abnormality involving either neurons in the substantia gelatinosa or internuncial fibers in Lissauer's tract is responsible for pain in patients with primary sensory nerve deafferentation is discussed.

A model of congenital hydrocephalus in utero in fetal lambs and rhesus monkeys has been produced by the intracisternal injection of kaolin. Initial attempts to produce hydrocephalus using silicone oil were unrewarding. Hydrocephalus had developed by 2 weeks post-injection and could be followed by ultrasonography. The pathological findings were similar to those reported using kaolin in other species. Ventriculoamniotic shunting, when successful, was capable of partially reversing the deleterious effects of hydrocephalus. The major drawback of the present model is that hydrocephalus is produced during the second rather than the first trimester of pregnancy. However, kaolin produces mainly an obstructive hydrocephalus without other associated brain or systemic anomalies.

The case of an 11-year-old boy is reported in whom two intramedullary lesions developed at the thoracic-cervical and thoracic-lumbar junctions 2 1/2 years after resection and irradiation of a medulloblastoma in the posterior fossa. There was no evidence of subarachnoid spread of the tumor. Magnetic resonance imaging was used to localize these lesions, and provided much better diagnostic information than either computerized tomography scans or myelograms.

Knowledge of normal suture anatomy and development is vital in order to understand abnormal suture development and to be able to distinguish sutures radiographically from normal anatomical structures and possible skull fractures. The anatomy of the sutures and synchondroses of 150 normal pediatric and adult patients was studied using high-resolution computerized tomography scanning. Sutures of both the calvaria and skull base were most accurately identified in axial and coronal high-resolution thin-section scans when bone window algorithms were used. Developmental changes of the sutures and synchodroses , the inner and outer tables, and the diploic space were all well delineated. Vault sutures could be identified routinely in children, but their presence in adults varied considerably. With increasing age, parasutural sclerosis developed and sutures were more closely apposed.

Nine patients with a peripheral nerve lesion (six intrinsic and three extrinsic) were evaluated with computerized tomography (CT). In all but one instance, the CT scans gave useful information regarding the anatomical location, size, and relationship of the lesion to surrounding structures. These cases illustrate the usefulness of CT as a diagnostic tool in the evaluation of peripheral nerve lesions.

Forty-five children harboring brain-stem tumors were treated at the University of California, San Francisco, between 1969 and 1979. Pathological diagnoses were made in 19 patients. All patients received radiation therapy (RT). Thirteen patients received chemotherapy before, during, or immediately after RT. Twenty-four patients were treated with chemotherapy at the time of tumor progression, after initial treatment with RT alone. No statistically significant difference in time to tumor progression or survival was found for treatment with chemotherapy as an adjuvant to RT compared to treatment with RT alone followed by chemotherapy administered at the time of tumor progression. There were, however, more long-term survivors in the group that was first treated with chemotherapy at the time of tumor progression. There was no statistically significant correlation between survival and tumor pathology or location, although there were more long-term survivors among patients harboring low-grade gliomas and among patients with tumors confined to the midbrain. The authors documented the response of some brain-stem tumors to chemotherapy; however, cooperative controlled studies will be required to determine the optimum treatment for this disease.

To determine the percentage of patients who developed multiple central nervous system (CNS) gliomas during postoperative radiation therapy and chemotherapy, the authors reviewed the records of 1047 patients treated between December 2, 1976, and August 16, 1985, who had an original diagnosis of supratentorial glioblastoma multiforme or other anaplastic glioma. The occurrence of multiple lesions was verified by neurodiagnostic studies (computerized tomography or myelography) or by findings at operation or autopsy. Twelve patients (1.1%) who presented with multiple lesions were excluded from this analysis. There were 405 patients with glioblastoma multiforme; their median age was 46.5 years (range 22 to 70 years). Eighteen (5%) of these patients had multiple CNS lesions, five of which were in the spinal cord. The median time from diagnosis to detection of the second lesion in this group was 59.5 weeks (range 10 to 182 weeks). There were 630 patients with anaplastic glioma (which included mixed malignant glioma and highly anaplastic, gemistocytic, moderately anaplastic, and anaplastic astrocytomas); their median age was 30 years (range 2 to 62 years). Fifty-four (8.6%) of these patients had multiple lesions, 10 of which were in the spinal cord; only one case of extraneural metastasis was found. The median time from diagnosis to detection of the second lesion in this group was 101 weeks (range 14 to 459 weeks). These results show that more than 90% of CNS gliomas recur at the site of the original tumor. Considering the high frequency of intellectual dysfunction after whole-brain radiation therapy, the use of focal radiation fields appears to be the most judicious approach to the treatment of patients with gliomas.

A consecutive series of 37 children (17 years old and under) with severe head injury is presented. The data confirm that morbidity and mortality are lower in children than in adults: 51% of these young patients had a good recovery or moderate disability at 6 months. The mortality rate in this series (33%) is higher than in some reports, but probably more closely approximates the death rate from these injuries in an unselected pediatric population than do statistics from tertiary care hospitals. There was no significant relationship between age and outcome in this age group, but mass lesions and uncontrolled intracranial hypertension adversely affected outcome. Diffuse cerebral swelling was commonly seen on computerized tomography scans, and generally was associated with a satisfactory outcome (75%). Two of 13 deaths were considered preventable, emphasizing the narrow therapeutic safety margin and extreme care required in treating these patients.

Twenty-seven patients aged 1 to 18 years harboring supratentorial (20 in the cerebrum and seven in the thalamus) malignant gliomas were treated between 1975 and 1982. There were four glioblastomas multiforme, 14 anaplastic astrocytomas, and nine malignant gliomas. All patients had a subtotal resection or biopsy as the initial procedure and received postoperative radiation therapy (RT). Fifteen of 27 patients were treated by RT alone; 14 had tumor progression with a median time to tumor progression (MTP) of 65 weeks. Twelve patients were treated with chemotherapy as an adjuvant to RT; only seven had tumor recurrence, with an MTP of 130 weeks. Of the 21 patients with recurrent tumors in both groups, 18 were treated with chemotherapy alone, or chemotherapy with a second surgical procedure or second course of RT. For all histological grades of tumor, the MTP for first recurrence was 75 weeks and the median survival time was 180 weeks. Age at initial diagnosis was found to be a statistically significant prognostic factor, with patients younger than 10 years of age surviving longer than patients aged over 10 years (p = 0.02).

The authors report survival data for the first 41 patients treated for recurrent malignant gliomas with interstitial brachytherapy at the University of California, San Francisco (1980-1984). Iodine-125 (125I) sources were temporarily implanted using stereotaxic techniques. The median survival period for 18 patients with recurrent glioblastomas was 52 weeks after brachytherapy; two patients are alive more than 5 years after brachytherapy. The median survival period for 23 patients with recurrent anaplastic astrocytomas is 153 weeks after brachytherapy, with 10 patients alive more than 3 years and four patients alive more than 4 years after brachytherapy. Both groups did significantly better (p less than 0.01) than groups of patients with the same diagnoses and similar general characteristics who were treated at recurrence with chemotherapy alone. Because of deterioration of their clinical condition and evidence of recurrence from computerized tomographic scans, 17 (41%) of 41 patients required reoperation 20 to 72 weeks after brachytherapy. Despite the invariable presence of apparently viable tumor cells mixed with necrotic tissue in the resected specimen, nine patients have survived more than 2 years after reoperation and two of the nine are still alive 4 years after reoperation. The authors conclude that brachytherapy with temporarily implanted 125I sources for well-circumscribed, hemispheric, recurrent malignant gliomas is effective and offers a chance for long-term survival even though focal radiation necrosis can seriously degrade the quality of survival in a minority of patients.

Intracerebral tumors were produced in 99 rats by stereotaxic implantation of 9L gliosarcoma brain-tumor cells. Hematoporphyrin derivative (HPD), 10 or 20 mg/kg, was administered as an intravenous bolus 24 or 48 hours before irradiation of the tumor region with light from an argon pumped-dye laser (632 nm). Laser light, at a dose of 30, 60, or 200 joules/sq cm, was delivered through a craniectomy 10 or 13 days after tumor implantation. Survival times were significantly prolonged in rats exposed to laser light at a dose of 200 joules/sq cm 24 hours after administration of HPD, 20 mg/kg.

The proliferative potential of low-grade astrocytomas was estimated in 47 patients. Each patient received an intravenous infusion of bromodeoxyuridine (BUdR), 150 to 200 mg/sq m, at the time of craniotomy to label cells in deoxyribonucleic acid (DNA) synthesis; the percentage of S-phase cells, or BUdR labeling index (LI), of each tumor was determined immunohistochemically. In 29 patients (60%), the tumors had BUdR LI's of less than 1%, indicating a slow growth rate; only three (10%) of these patients died of recurrent tumor during a follow-up period of up to 3 1/2 years. In contrast, of the 18 patients (40%) whose tumors had BUdR LI's of 1% or more, 12 (67%) had a recurrence and nine died during the same follow-up period. These results show that the proliferative potential, as reflected by the BUdR LI, is an important prognostic factor that separates low-grade astrocytomas into two groups and provides a more scientific rationale for selecting treatment for individual patients.

Primary cerebral neuroblastoma is a distinct pathological and clinical entity that differs from other primitive neuroectodermal tumors. To characterize the clinical course of this lesion, the authors performed a retrospective analysis in 11 patients who ranged in age from 17 months to 26 years. The tumor had no predilection for either sex. Signs and symptoms were mostly those associated with increased intracranial pressure. The lesions commonly involved the parietal and occipital lobes. Computerized tomography scans of nine patients showed five solid and four cystic lesions; calcifications were found more commonly in the solid lesions. Contrast enhancement was seen in all tumors, yet angiograms typically showed an avascular mass. Total removal of tumor was possible in only two patients, both with cystic tumors. The remaining nine underwent subtotal resection of a solid lesion (in five) or a cystic lesion (in four). All 11 patients underwent postoperative irradiation that included the spinal axis in two cases; only one received adjuvant chemotherapy (solid tumor). Four patients, all with solid tumors that initially were subtotally resected, had evidence of tumor recurrence. The only patient with a subtotally resected solid lesion who did not have recurrence received adjuvant chemotherapy. The six patients who had cystic lesions are free of recurrent tumor at 26 to 109 months after surgery. Based on follow-up analysis of the 11 patients, recommendations are proposed for the treatment of primary cerebral neuroblastomas.

A 13-year-old girl developed an anaplastic astrocytoma of the cerebellum 7 years after irradiation of the central nervous system and prophylactic chemotherapy for acute lymphocytic leukemia. The fact that the astrocytoma was anaplastic and infiltrative was unusual for astroglial tumors at this site. It is proposed that this is a radiation-induced glioma.

The use of lasers in neurosurgical procedures has received a great deal of attention recently. Surgical use of lasers has been viewed with suspicion and skepticism, probably because of (justified) apprehensions about the misuse of lasers in early work and about the ways in which laser light affects tissues, and a lack of understanding of the basic physics and practical operation of lasers. The authors review the physics, biophysics, experimental findings, and operative use of lasers in current neurosurgical practice, and discuss briefly their experience gained in over 150 neurosurgical procedures using the carbon dioxide and argon surgical lasers.