Endoscopic resection of colloid cysts: indications, technique, and results during a 13-year period.

OBJECTIVE: Questions of recurrence and inadequacy of follow-up length persist regarding endoscopic treatment of colloid cysts. In this retrospective review, we report our long-term follow-up during a 13-year period in 35 patients who underwent endoscopic resection of colloid cysts. METHODS: The 19 males and 16 females (age range 14 to 58 years, mean 35.9 years) who had symptomatic colloid cysts that ranged in size from 5 mm to 4 cm underwent endoscopic resection in the period from 1991 to 2004. RESULTS: Of 2 patients who developed recurrences at 5.9 years and 4.3 years (1 and 6 mm, respectively) both remain asymptomatic. The rate of late asymptomatic recurrence in this series is 6.3%. Three endoscopic resections were converted to an open craniotomy. Three operative complications occurred (i.e., introducer tract hemorrhage, thalamic stroke secondary to thermal injury, epidural hematoma that required evacuation). Four patients noted minimal short-term memory loss without interference in daily living. Of 3 patients with shunts preoperatively, all have no evidence of hydrocephalus after shunt removal. Two patients have asymptomatic ventriculomegaly. Prophylactic anticonvulsants were not prescribed and no seizures were reported. No infections were recorded with antibiotic administration preoperatively, and 24 hours postoperatively. CONCLUSIONS: Our series represents the longest follow-up (mean of 7.8 years) of colloid cysts after endoscopic resection. We now use this technique as the first line of treatment for colloid cysts. The risk of recurrence is minimal with gross total resection and/or coagulation of the cyst wall.

Gradual formation of an operative corridor by balloon dilation for resection of subependymal giant cell astrocytomas in children with tuberous sclerosis: specialized minimal access technique of balloon dilation.

BACKGROUND: Major sources of morbidity and mortality in patients with tuberous sclerosis who develop subependymal giant cell astrocytomas (SEGAs) relate to tumor growth and resultant hydrocephalus. We describe a modification of a specialized minimal access resection technique in which an operative corridor is formed with balloon dilation over the course of a week prior to tumor resection. METHODS: Three patients with tuberous sclerosis who had an enlarging SEGA and concomitant hydrocephalus underwent surgical resection with this modified technique. A frontal craniotomy was performed and the optimal trajectory for tumor resection was confirmed by image guidance. After initial insertion of the deflated balloon into the ventricle and removal of the peel-away sheath, inflation of the balloon with a 1-mL saline injection sealed the tract. Additional 1-mL saline injections were continued during the next week until the balloon reached a 15-mm diameter, thus creating the operative corridor. One week after the first operation, the balloon was deflated and removed, and the patient underwent tumor resection via the newly formed operative corridor. RESULTS: Three patients with tuberous sclerosis underwent gross total resections of SEGAs and experienced subsequent resolution of ventricular dilation. Postoperative imaging confirmed minimal cortical disruption. CONCLUSIONS: Use of balloon dilation for the gradual formation of an operative corridor eliminated the need for additional retraction during SEGA resection, potentially decreasing injury to the surrounding neural tissue. In our three patients, the dilation tract retained its integrity during the operation and had sealed completely on postoperative imaging.

Children with macrocrania: clinical and imaging predictors of disorders requiring surgery.

BACKGROUND AND PURPOSE: Macrocrania is a common pediatric clinical condition affecting up to 5% of the population. The purpose of this study was to determine clinical and imaging predictors that are useful in the differentiation of disorders requiring surgical treatment from those that can be treated medically in children with macrocrania. METHODS: In a 3-year 7-month retrospective study, 88 patients (median age, 8 months; interquartile range, 5--13 months) with macrocrania and no known underlying neurologic disorder underwent imaging of the brain (sonography, n = 36; CT, n = 31; MR imaging = 21). The study was conducted in a pediatric tertiary care referral center. Clinical and imaging data were correlated to final diagnosis by means of logistic regression and receiver operating characteristic curves. RESULTS: Sixteen (18%) of the patients had disorders requiring surgery: communicating hydrocephalus, n = 7; noncommunicating hydrocephalus, n = 3; hemorrhagic subdural collections, n = 3; neoplasm, n = 1; encysted cavum septi pellucidi, n = 1; and vein of Galen malformation, n = 1. Clinical predictors of disorders requiring surgery included vomiting (P =.007), labor instrumentation (P =.026), developmental delay (P =.008), and abnormal neurologic findings (P =.028). Imaging predictors of disorders requiring surgery included a focal space-occupying lesion (P <.0001) and moderate-to-severe ventriculomegaly (P <.0001). The diagnostic sensitivity of the combination of independent clinical and imaging predictors was higher than that of independent clinical predictors alone, being 100% (95% confidence interval = 96.9%, 100%) and 93.8% (95% confidence interval = 88.7%, 98.8%), respectively. A trend indicated that the area under the receiver operating characteristic curve for clinical plus imaging findings (0.95) was greater than that for clinical findings alone (0.85) (P =.09). An increase in the number of clinical and imaging predictors was highly correlated with an increased risk of a disorder requiring surgery (P <.0001). CONCLUSION: Baseline neuroimaging is indicated for children with macrocrania because the combination of clinical and imaging predictors has the best diagnostic performance in determining the need for surgical versus nonsurgical management.

Achondroplasia and cervicomedullary compression: prospective evaluation and surgical treatment.

The association between sudden death and cervicomedullary compression in infants with achondroplasia has been well described. Prospective clinical and imaging evaluations have been recommended to identify those infants with achondroplasia who are at risk of dying suddenly from respiratory arrest secondary to unrecognized cervicomedullary compression. Since 1988, we have prospectively evaluated 11 infants (average age 13 weeks) with achondroplasia who were asymptomatic for cervicomedullary compression on initial clinical evaluation. Craniocervical magnetic resonance imaging (MRI) findings included narrowing of the foramen magnum, effacement of the subarachnoid spaces at the cervicomedullary junction, abnormal intrinsic cord signal intensity and mild to moderate ventriculomegaly. Two patients with severe cord compression underwent immediate decompression. Two patients developed opisthotonic posturing within 3 months of evaluation and underwent foramen magnum decompression, including suboccipital craniectomy and atlantal laminectomy. Surgery in all cases revealed forward extension of the squamous portion of the occipital bone, thickened posterior rim of the foramen magnum and a dense fibrotic epidural band. There were no complications from surgery. Seven patients did not require surgery and were followed closely. All 11 patients remain asymptomatic at follow-up (mean 4.6 years; range 16 months to 7.3 years), and no patient has required a diversionary shunt procedure. The results of this prospective study confirm that early clinical and MRI evaluations are necessary to determine whether infants with achondroplasia have cervicomedullary compression. With early recognition, an immediate decompression can be performed safely to avoid serious complications associated with cervicomedullary compression, including sudden death.

Atretic parietal cephaloceles revisited: an enlarging clinical and imaging spectrum?

PURPOSE: We describe imaging features that are clues to the diagnosis of atretic cephaloceles and discuss clinical findings and a possible mechanism by which these lesions develop. METHODS: Eight children (five girls and three boys) ranging in age from 1 day to 3 years 4 months with midline subscalp lesions underwent radiologic examination with CT or MR imaging. In all cases, the lesions were surgically excised and subjected to pathologic examination. Imaging studies and medical records were reviewed retrospectively. RESULTS: Six of eight children had vertical embryonic positioning of the straight sinus with a prominent superior cerebellar cistern. A "spinning-top" configuration of the tentorial incisura, a "cigar-shaped" CSF tract within the interhemispheric fissure, fenestration of the superior sagittal sinus, and "peaking" of the tentorium were associated findings helpful in making this diagnosis. Two of the eight children had findings indistinguishable from focal dermoid, six were developmentally normal, one had mild motor delay, and one died at the age of 3 years. Pathologic examination revealed glial, meningeal (arachnoid), fibrous, and dermal elements. CONCLUSION: Characteristic findings on MR images and CT scans provide clues to the diagnosis of atretic cephalocele. However, even in the presence of abnormal imaging findings, these children may be developmentally normal.

Formation of intracerebral cavernous malformations after radiation treatment for central nervous system neoplasia in children.

OBJECT: Radiation is a common treatment modality for pediatric brain tumors. The authors present a retrospective review of six children who developed cerebral cavernous malformations after they underwent radiation treatment for central nervous system (CNS) neoplasia and propose two possible models to explain the formation of cavernous malformations. METHODS: Three boys, aged 13, 9, and 17 years, suffered intracerebral hemorrhages from cerebral cavernous malformations 87, 94, and 120 months, respectively, after they received whole-brain radiation therapy (WBRT) for acute lymphocytic leukemia. A 10-year-old girl and a 19-year-old man developed temporal lobe cavernous malformations 46 and 48 months, respectively, after they received radiation therapy for posterior fossa astrocytomas. A 12-year-old girl developed a temporal lobe cavernous malformation 45 months after WBRT was administered for a medulloblastoma. In all of these cases the cavernous malformation appeared in the irradiated field, was not known to be present prior to radiation therapy, and developed after a latency period following treatment. The incidence of cavernous malformations in these patients suggests that children who undergo radiation therapy of the brain may have an increased risk of hemorrhage. CONCLUSIONS: Two possible models may explain the formation of cavernous malformations following brain radiation in these patients. First, the cavernous malformations may form de novo in response to the radiation. Second, the cavernous malformations may have been present, but radiographically occult, at the time of radiation therapy and may have hemorrhaged in response to the radiation. The authors conclude that cavernous malformations may develop after brain radiation and propose a possible mechanism for this formation.

Transpalatal approach for the extracranial surgical repair of transsphenoidal cephaloceles in children.

The surgical treatment of transsphenoidal cephaloceles in children is controversial. Reduction and repair via a transcranial approach are associated with high postoperative rates of morbidity, mortality, and hypothalamic dysfunction. In this study, four patients, aged 3 to 35 months at surgery, underwent successful transpalatal repair of two encephaloceles and two meningoceles. Two patients presented with nasal obstruction in infancy, one presented with unexplained meningitis, and in one patient the lesion was found incidentally during evaluation for seizures. Two children had median cleft face syndrome, another had an associated Arnold-Chiari type I malformation, and the fourth had no other cranial abnormalities. All patients underwent preoperative evaluation including magnetic resonance (MR) imaging. Auditory, ophthalmological, genetic, endocrinological, or other evaluation was undertaken as indicated. Lesions were approached through the median raphe of the hard and soft palates. All cephaloceles were easily visualized and dissected after division of the nasal palatal mucosa. The dural sac and its contents were reduced by surface coagulation after division and dissection of the overlying mucosa. Once reduced, the bone defect was obliterated in three of four patients. The dura was not opened and anomalous neural elements were not resected. At follow-up evaluation, all patients demonstrated resolution of preoperative symptoms without evidence of infection or lasting morbidity. Follow-up MR imaging showed reduction in all cases. The authors conclude that this transpalatal approach is safe and reliable for the treatment of transsphenoidal cephaloceles in young children.

Endoscopic treatment of loculated hydrocephalus.

Loculated hydrocephalus remains a difficult neurosurgical problem and endoscopes designed to navigate through the ventricular system provide a new option for treatment. The authors review their experience, during the period March 1990 to June 1993, using a steerable fiberscope in 34 cases of loculated hydrocephalus to evaluate the efficacy of endoscopic cyst fenestration. The goals of treatment were to control hydrocephalus, simplify preexisting shunt systems, and reduce operative morbidity. Endoscopic cyst fenestrations reduced the shunt revision rate from 3.04 per year prior to endoscopy to 0.25 per year after the procedure, during a follow-up period ranging from 8 to 45 months, mean 26 months. However, eight patients (23.5%) required 14 repeat operations to control loculated hydrocephalus. After endoscopy, patients with multiloculated hydrocephalus had a nearly fivefold increased risk (relative risk 4.85) for shunt malfunction and more than a twofold increased risk (relative risk 2.43) for cyst recurrence versus patients with uniloculated hydrocephalus. Similarly, six (50%) of 12 patients shunted prior to endoscopy required a repeat endoscopic procedure (relative risk 5.56). Although repeat endoscopic procedures may be required to control hydrocephalus, endoscopic cyst fenestration avoided placement of a shunt in seven (33%) of 21 patients with uniloculated hydrocephalus. One patient, encountered early in the authors' experience, required a craniotomy for fenestration of multiple ventricular cysts. Endoscopic complications included cerebrospinal fluid leakage in one case and ventriculitis in another. The authors conclude that endoscopic treatment of loculated hydrocephalus is a safe, minimally invasive technique that should be considered as the initial treatment option.

Surgical resection of third ventricle colloid cysts. Preliminary results comparing transcallosal microsurgery with endoscopy.

It is still not determined which is the best surgical option for third ventricle colloid cysts. Since 1990, the authors have used a steerable fiberscope to remove colloid cysts in seven patients and have performed microsurgery via a transcallosal approach in eight patients. The two techniques were compared for operating time, length of hospital stay, incidence of complications, recurrence, and hydrocephalus, and days spent recuperating before return to work to determine if endoscopic removal of colloid cysts is a safe and effective alternative to microsurgery. Statistical analysis was adjusted for age, sex, and presenting symptoms. Microsurgical cases averaged 206 minutes of operating time whereas endoscopic cases averaged 127 minutes (p = 0.01). For combined days spent in the intensive care unit and on the ward, the patients averaged 9.5 days after microsurgery and 4 days after endoscopy (p = 0.05). Postoperative complications occurred in five of eight patients after microsurgery and in one of seven patients after endoscopy (p = 0.09); complications were transient and primarily related to short-term memory loss. In all patients, preoperative symptoms resolved and the cysts have not recurred. Postoperatively, one patient required a ventriculoperitoneal shunt after microsurgery but all patients were shunt-independent after endoscopy. Patients returned to work an average of 59 days after discharge following microsurgery compared with an average of 26 days after endoscopy (p = 0.05). Compared with transcallosal microsurgery for the removal of colloid cysts, these preliminary results show that a steerable endoscope reduced operating time and that patients spent fewer days in the hospital and returned to work sooner after endoscopy.

The role of hemispherectomy in the treatment of holohemispheric hemimegaloencephaly.

The role of hemispherectomy in treating holohemispheric hemimegaloencephaly, a unilateral brain malformation, is still not well defined. The authors describe the cases of five infants presenting with intractable seizures, progressive neurological deficits, and severe developmental delay. Electroencephalography (EEG) showed generalized polyspikes from the megaloencephalic hemisphere and progressive slowing on the opposite side in all children; contralateral seizure spikes occurred in three children. Three of the five children underwent hemispherectomy for intractable seizures before 2 years of age, after which the seizures subsided completely in two children and improved remarkably in the third. Preoperative Wada testing proved useful in evaluating pharmacologically the effect of hemispherectomy on contralateral polyspikes. Postoperative EEG revealed the absence of polyspikes in the operated hemisphere and decreased slowing on the contralateral side. Psychomotor development in the surgically treated infants exceeded that of the children not undergoing hemispherectomy. Of the two children treated medically, one died at 4 years of age in status epilepticus and the other (now 5 years old) has frequent seizures and severe developmental delay. Based on these results, hemispherectomy appears to be a useful procedure for controlling seizures and improving psychomotor development in children with hemimegaloencephaly involving the entire hemisphere. Surgery in infancy can prevent or minimize seizure foci and encephalopathic changes that may develop in the contralateral hemisphere. Staging the procedure and exercising meticulous hemostasis make surgery relatively safe in infants who otherwise may have significant blood loss associated with increased blood flow to the megaloencephalic hemisphere.

Meningioangiomatosis of the brain stem. Case report.

The case is reported of meningioangiomatosis of the brain stem in a 3 1/2-year-old girl who suffered from vomiting, left facial weakness, difficulty in swallowing, and ataxia. This is believed to be the first reported case of meningioangiomatosis in the brain stem. Computerized tomography showed an intensely enhancing hyperdense mass in the left restiform body. Magnetic resonance imaging revealed that the lesion was isointense to gray matter on the T1-weighted image and hypointense on the T2-weighted image, with a surrounding zone of high T2 signal and intense enhancement. Angiography was normal. Surgical exploration demonstrated an intramedullary firm mass that was partially resected. Histologically, the mass consisted of a low-grade lesion of meningeal origin with spindle cells in a whorling pattern that were occasionally focused around small vessels. On 2-year follow-up imaging, the lesion remains unchanged in size. Certain particularities of this lesion are discussed in the context of the literature.

Acquired Chiari malformations: incidence, diagnosis, and management.

The acquired descent of the cerebellar tonsils radiographically indistinguishable from Chiari I malformations has been previously reported. The relationship between lumbar shunting procedures for hydrocephalus and symptomatic Chiari malformations has been established. We report the cases of 10 children with lumboperitoneal shunts in whom previous radiographic studies had confirmed a normal hindbrain configuration. Seven of the 10 patients acquired tonsillar descent into the foramen magnum, detected by magnetic resonance imaging, whereas the others remained normal. Four of seven patients were symptomatic; two underwent the removal of the lumboperitoneal shunt and conversion to a ventriculoperitoneal shunt, and two underwent posterior fossa decompression. Further magnetic resonance imaging revealed that one of the two patients who underwent conversion shows ascent of the cerebellar tonsils. All four patients became asymptomatic less than 6 months after treatment. In this article, we discuss seven cases of acquired Chiari malformations and the complete reversal of an acquired Chiari malformation after surgical treatment, as documented by magnetic resonance imaging. Cases of asymptomatic acquired Chiari malformations are reported, including those resulting from shunting for intracranial hypertension without hydrocephalus. We conclude that a craniospinal pressure gradient creates a potential for cerebellar tonsil descent and recommend that ventriculoperitoneal shunting be performed in children with communicating hydrocephalus to avoid this potential complication. We also recommend annual surveillance of the cervicomedullary junction in children with lumboperitoneal shunting. Finally, if symptomatic tonsillar descent occurs from lumbar shunting, a trial conversion to ventriculoperitoneal shunting may eliminate the need for posterior fossa decompression.

Intraoperative uses of ultrasound in the pediatric neurosurgical patient.

Ultrasound imaging has become a common method for intraoperative evaluation of the central nervous system. Real-time monitoring aids in guidance for aspiration of fluid collections and placement of catheters as well as the localization and evaluation of masses, and confirmation of their complete removal. Color Doppler is useful in the evaluation of blood flow in arteriovenous malformations, aneurysms, and neoplasms. Consultation among the ultrasound staff, neuroradiologists, and neurosurgeons before the operative procedure maximizes the usefulness of ultrasound, thus aiding in the success of surgery.

Color Doppler US imaging during pediatric neurosurgical and neuroradiologic procedures.

Experience with color Doppler imaging (CDI) during 16 pediatric intraoperative and one percutaneous neuro-radiologic procedures was reviewed to assess whether CDI increased the success rate or decreased the procedure time, thus contributing substantially to procedure performance. Intraoperative CDI was used to rapidly identify abnormal vessels or displacement of normal vessels and correlated with preoperative studies. In six cases (four vascular malformations, one mycotic aneurysm, and one hamartoma), surgical resection was altered on the basis of flow information obtained. In one case of percutaneous embolization of a Galenic malformation, CDI provided information contributing to the cessation of the procedure. In six cases (debulking of three gliomas, resection of one vascular malformation, and two biopsies of nonneoplastic conditions), information was added but did not alter the surgical approach. In the remaining four cases (three cerebrospinal fluid drainage procedures, one posterior fossa decompression), no additional information was obtained. Consultation among the ultrasound staff, neuroradiologists, and neurosurgeons before the operative procedure maximized the usefulness of CDI, thus aiding in the success of surgery.

Bilateral congenital ocular cysts.

This report presents an unusual case of bilateral congenital ocular cysts. These are in the spectrum of congenital cystic eye and microphthalmos with cysts. Diagnostic evaluation, including orbital B-scan ultrasonography, computed tomography and magnetic resonance imaging is described. Pathologic evaluation of the orbital cysts was consistent with congenital cystic eye. An associated microphthalmic eye was not detected with serial sectioning of both specimens. Examination of the orbit at exploration as well as pre- and post-operative MRI scans failed to demonstrate the presence of a microphthalmic eye in either orbit. Failure to detect a microphthalmic eye clinically, by diagnostic imaging studies, or serial microscopic sections of the cysts supports the diagnosis of congenital cystic eye. This child has associated mild facial clefting (median cleft lip and cleft palate) and basal cephalocele. Histopathologically documented cases of ocular abnormalities associated with basal encephalocele have not been reported. To the authors' knowledge, MRI findings of congenital ocular cysts have been reported once previously in a case of microphthalmos with cyst, however, histopathologic correlation has not been reported previously.

Magnetic resonance imaging of fourth ventricular choroid plexus neoplasms in childhood. A report of two cases.

Choroid plexus neoplasms (CPN) are rare tumors occurring with a relative incidence of 0.5% of intracranial neoplasms in all age groups and 1.5-6.4% of all pediatric brain tumors. In children, the most common site of origin is the atria of the lateral ventricles where the CPN may represent either a carcinoma or a benign papilloma. CPN arising in the fourth ventricle are more common in adults, and are more likely to represent a benign papilloma. We present 2 children with CPN arising from the inferior fourth ventricle with similar features on MRI, one of which represented a benign papilloma and the other a malignant carcinoma. CPN should be included, even in young children, in the differential diagnosis of any infratentorial, intraventricular tumor.

Management of cerebral cavernous angiomas in children presenting with seizures.

Until recently intracranial cavernous angiomas were thought to be rare vascular malformations that usually presented in adulthood as an intracerebral hemorrhage, an expanding mass lesion, or with the new onset of seizures. Prior to the advent of computed tomography (CT), and more recently magnetic resonance imaging (MRI), their diagnosis in childhood was extremely rare. However, the CT and MRI features of cavernous angioma are quite distinctive and allow early diagnosis and treatment. Advances in surgical techniques permit successful removal of these potentially devastating lesions and amelioration of the associated seizure disorder. Seven children with cerebral cavernous angiomas have been treated at the Children's Hospital Medical Center since 1980. Six children presented with seizures and one with an intracerebral hemorrhage. All had characteristic findings on CT and/or MRI and underwent surgical excision of symptomatic lesions. Intraoperative sonography, electrocorticography, and cortical mapping were used when indicated and were found to be helpful in the surgical management of these patients. Our experience suggests that symptomatic cerebral cavernous angiomas in children are not as rare as previously thought and that surgical treatment using modern neurosurgical techniques is both safe and appropriate and can be helpful in the management of associated seizures.

Relationship between flow cytometric features and clinical behavior of meningiomas.

Meningiomas have a wide range of biological potential and clinical behavior. Histological findings are helpful in recognizing the malignant potential of a given tumor, but often fail to correlate with gross features, liability of recurrence, and extent of associated cerebral edema. To find alternate approaches to improve the correlation between biological and clinical behavior, 20 meningiomas were studied by flow cytometry (FC), an assessment that has been applied to meningiomas previously. Such FC features as DNA index (DI) and proliferative index (PI, %G2 + %S) were correlated with size, location, brain invasion, associated edema, and recurrence. Tumors with severe edema had significantly higher PIs (19.5 +/- 4.1) than those with moderate (12.6 +/- 4.5) or minimal (8 +/- 0) edema (P less than 0.05). The PI was greater than 16 in those tumors that recurred (n = 3) or invaded the brain (n = 3). Six tumors were aneuploid (DI, 1.33 +/- 0.17; PI, 17.1 +/- 5.3). These were uniformly large when compared with the diploid tumors, which were more variable in size. All of the aneuploid tumors were associated with moderate to severe cerebral edema. Two partly psammomatous tumors with high PIs and foci of high cellularity suggesting recent growth were associated with severe edema. One of these exhibited brain invasion. These preliminary data indicate that FC may have a potential use in the clinical management of meningiomas.

Chronic vermal herniation in a case of osteosarcoma of the occipital bone.

Upward projection of the cerebellar vermis through the tentorial hiatus is called upward vermal herniation (UVH). UVH is less common in clinical practice than uncal herniation. Even more uncommon is chronic vermal herniation and impaction in the tentorial hiatus. To illustrate this phenomenon, we present the clinical, radiological, and morphological features of vermal impaction in a patient with a postradiation osteosarcoma of the occipital bone. In spite of nearly total excision of the tumor pushing the cerebellum upward, his postoperative course was complicated by respiratory problems and an altered level of consciousness, finally resulting in death. His clinical status paralleled the computed tomographic (CT) demonstration of persistent obliteration of the supramesencephalic cistern. CT makes more reliable the detection and management of UVH, but a high index of suspicion is necessary for prevention of this complication.