Brain and Spinal Tumors Originating from the Germ Line Cells.

Primary central nervous system germ cell tumors (CNS GCTs) are part of the GCTs in children and adults. This tumor entity presents with geographic variation, age, and sex predilection. There are two age peaks of incidence distribution at the first few months of life and in adolescence. CNS GCTs are heterogeneous in histopathological subtypes, locations, and tumor marker (AFP, ß-hCG) secretions. In the WHO CNS tumor classification, GCTS are classified as germinoma and nongerminomatous GCT (NGGCT) with different subtypes (including teratoma). Excluding mature teratoma, the remaining NGGCTs are malignant (NGMGCT). In teratoma, growing teratoma syndrome and teratoma with somatic-type malignancy should be highlighted. The common intracranial locations are pineal region, neurohypophysis (NH), bifocal pineal-NH, basal ganglia, and cerebral ventricle. Above 50% of intracranial GCTs (IGCTs) present obstructive hydrocephalus. Spinal tumors are rare. Age, locations, hydrocephalus, and serum/CSF titer of ß-hCG correlate with clinical manifestations. Delayed diagnosis is common in tumors arising in neurohypophysis, bifocal, and basal ganglia resulting in the increasing of physical dysfunction and hormonal deficits. Staging work-up includes CSF cytology for tumor cells and contrast-enhanced MRI of brain and spine for macroscopic metastasis before treatment commences. The therapeutic approach of CNS GCTs integrates locations, histopathology, staging, tumor marker level, and therapeutic classification. Treatment strategies include surgical biopsy/excision, chemotherapy, radiotherapy (single or combination). Secreting tumors with consistent imaging may not require histopathological diagnosis. Primary germinomas are highly radiosensitive and the therapeutic aim is to maintain high survival rate using optimal radiotherapy regimen with/without chemotherapy combination. Primary NGNGCTs are less radiosensitive. The therapeutic aim is to increase survival utilizing more intensive chemotherapy and radiotherapy. The negative prognostic factors are residue disease at the end of treatment and serum or CSF AFP level >1000 ng/mL at diagnosis. In refractory or recurrent NMGGCTs, besides high-dose chemotherapy, new therapy is necessary. Molecular profiling and analysis help for translational research. Survivors of pediatric brain tumors frequently experience cancer-related cognitive dysfunction, physical disability, pituitary hormone deficiency, and other CNS complications after cranial radiotherapy. Continuous surveillance and assessment may lead to improvements in treatment protocols, transdisciplinary interventions, after-treatment rehabilitation, and quality of life.

Correlation between intraoperative mapping and monitoring and functional outcomes following supratentorial glioma surgery.

OBJECTIVES: Intraoperative neurophysiological monitoring (IONM) has long been regarded as the "gold standard" when resecting a supratentorial glioma, as it facilitates the goals of maximal tumor resection and preservation of sensorimotor function. The purpose of the present study was to evaluate the ability of motor evoked potentials (MEPs) monitoring or subcortical mapping (SCM), alone or in combination, to predict postoperative functional outcomes in glioma surgery. MATERIALS AND METHODS: We retrospectively reviewed patients with supratentorial glioma that underwent craniotomy for tumor removal with IONM. Statistical analyses were used to evaluate whether the following criteria correlated with postoperative functional outcomes: Reduced amplitude (>50% reduction) or disappearance of MEPs (criterion 1), SCM with a stimulation intensity threshold less than 3 mA (criterion 2), the presence of both two phenomena (criterion 3), or either one of the two phenomena (criterion 4). RESULTS: Ninety-two patients were included in this study, of whom 15 sustained new postoperative deficits, 4 experienced improved functional status, and 73 were unchanged. Postoperative functional status correlated significantly with all four criteria, and especially with criterion 3 (r = 0.647, P = 0.000). Sensitivity of IONM was better if using criteria 2 and 4, but specificity was better if using criteria 1 and 3. Criterion 3 had the most favorable overall results. CONCLUSION: Using statistical methodology, our study indicates that concomitant interpretation of MEPs and SCM is the most accurate predictor of functional outcomes following supratentorial glioma surgery. However, accurate interpretations of the monitoring results by experienced neurophysiologists are essential.

Impact of extent of internal acoustic meatus tumor removal using translabyrinthine approach for acoustic neuroma surgery.

OBJECTIVES: Many studies have investigated the surgical outcome and predictive factors of acoustic neuroma using different approaches. The present study focused on large tumors due to the greater likelihood of internal acoustic meatus involvement and the greater application of surgical intervention than radiosurgery. There have been no previous reports on outcomes of internal acoustic meatus tumor removal. We investigated the impact of the extent of internal acoustic meatus tumor removal using a translabyrinthine approach for large acoustic neuroma surgery and predictive factors of tumor control. METHODS: This retrospective study reviewed 104 patients with large cerebellopontine angle tumor >3 cm treated by translabyrinthine approach microsurgery. Predictive factors of postoperative facial palsy, tumor control, and extent of internal acoustic meatus tumor removal were assessed. RESULTS: The mean tumor size was 38.95 ± 6.83 mm. Postoperative facial function showed 76.9% acceptable function (House-Brackmann grade 1 or 2) six months after surgery. The extent of internal acoustic meatus tumor removal was a statistically significant predictor factor of poor postoperative facial function. Younger age, larger tumor size needing radiosurgery, and more extensive removal of tumor were associated with better tumor control. CONCLUSION: More extensive internal acoustic meatus tumor removal was associated with poor postoperative facial function and better tumor control.

Blink synkinesis monitoring during microvascular decompression for hemifacial spasm.

BACKGROUND: In the present study, we investigated whether blink synkinesis monitoring during microvascular decompression (MVD) is effective for predicting long-term outcomes in patients with hemifacial spasm (HFS). METHODS: This retrospective study included 69 patients who had undergone MVD for HFS at a tertiary hospital. All patients underwent intraoperative monitoring of blink synkinesis, lateral spread responses (LSRs), and facial nerve motor-evoked potentials (FNMEPs). Baseline signals were compared to those obtained following decompression with Teflon, and postoperative outcomes were recorded. RESULTS: A total of 65 patients were observed with complete relief of symptoms after 1 year after MVD, while 61 patients were observed with initial disappearance of blink synkinesis, 57 patients were observed with initial elimination of the LSR, and 45 patients with initial decreases in FNMEP amplitude (>50%). The highest sensitivity and accuracy values were observed for blink synkinesis. Chi-square tests comparing the sensitivity of the three methods revealed that FNMEP monitoring was associated with significantly lower sensitivity values than the remaining methods. Combined use of blink synkinesis and LSRs did not significantly increase sensitivity (61/65 vs 62/65) or accuracy (62/69 vs 63/69). CONCLUSION: Our results demonstrate that blink synkinesis monitoring is safe during MVD for HFS. Furthermore, blink synkinesis was associated with the highest sensitivity and predictive values among the three methods evaluated. These findings suggest that blink synkinesis can be regarded as the first choice for intraoperative monitoring during MVD. Concurrent use of blink synkinesis and LSR monitoring may maximize the ability to predict patient prognosis and determine the extent of decompression.

Using subdural strip electrodes to define functional sensory nerves and the most inferior functional portion of the conus medullaris during detethering surgeries for tethered cord syndrome: a pilot study.

OBJECTIVE: The aim of this study was to investigate the feasibility of using subdural strip electrodes, placed just rostral to the surgical field, to record sensory evoked potentials (SEPs) from the lumbosacral sensory nerves and define the most inferior functional portion of the conus medullaris during detethering surgery for spinal dysraphism and/or tethered cord syndrome (TCS). METHODS: Six patients, 2 boys and 4 girls, aged 0.5 to 16 years, were enrolled in this study. One patient had lipomyelomeningocele-related, 4 had myelomeningocele-related, and 1 had diastematomyelia and lipomyelomeningocele-related TCS. In addition to the routine preparations that are needed for performing functional mapping and monitoring during surgery for spinal dysraphism and TCS, the patients had a 1 × 4 strip of electrodes placed rostral to the surgical field, where it was secured by a surgeon after opening the dura. With the patient under total intravenous anesthesia, the sensory nerves and conus medullaris were stimulated with a concentric bipolar electrode over the surgical field while SEPs were recorded with the strip electrodes to identify any possible sensory roots with remaining function and the most inferior functional portion of the conus medullaris. RESULTS: The SEP amplitudes that were recorded with the subdural strip electrodes ranged from 4 to 400 µV, and the responses to sensory nerve stimulation were frequently much larger than were those to conus stimulation. Use of the SEP recordings for sensory mapping along with the routine mapping and monitoring techniques allowed detethering to be completed such that none of the patients sustained any new functional deficit after surgery. CONCLUSIONS: Recording SEPs from the functional sensory nerves and conus medullaris through subdural strip electrodes proved to be a feasible and valuable tool during detethering surgery in young patients. This approach may help surgeons achieve maximal detethering while preserving important sensory functions, consequently retaining the patient's quality of life.

Pattern of Corticospinal Projections Defined by Brain Mapping During Resective Epilepsy Surgery in a Patient with Congenital Hemiparesis and Intractable Epilepsy.

BACKGROUND: Congenital or early-onset brain structural lesions often cause contralateral hemiparesis, cognitive deficits, developmental delays, and seizures. Seizure is the most debilitating condition, as it greatly impairs quality of life in both the affected individuals and their caregivers and prevents them from active social participation. CASE DESCRIPTION: A 34-year-old man with hemiparesis and early-onset seizures since childhood owing to a congenital brain lesion developed intractable seizures in the last 2 years and was subsequently admitted for resective epileptic surgery. During the operation, we employed an innovative intraoperative neurophysiologic monitoring technique. In contrast to routine application for transcranial stimulation, we recorded compound muscle action potentials over the bilateral limb muscles simultaneously, instead of over the contralateral muscles only, to determine the patterns of the corticospinal projections. Transcranial stimulation over the bilateral hemispheres was applied before craniotomy, and direct cortical stimulation over the lesioned hemisphere was applied after craniotomy. By integrating both approaches, we could first identify the pattern of corticospinal projections before craniotomy and then accurately define the noneloquent area, which guided the resection to successfully accomplish the surgical goal. CONCLUSIONS: This technique is simple because no patient participation is required. We believe that it has the potential to replace conventional preoperative functional magnetic resonance imaging and transcranial magnetic stimulation in resective epilepsy surgery, particularly for young patients. Not only can it improve the safety of surgical procedures, but also it can help predict functional outcome.

Localization of the trunk muscles using musculoskeletal ultrasound guidance for pedicle screw stimulation during spine surgery.

The precise placement of recording electrodes at the relevant myotome is mandatory while performing pedicle screw stimulation (PSS) during spine surgery; however, their placement at trunk muscles is challenging. This study aimed to determine whether ultrasound guidance is useful for trunk muscle localization for PSS during spine surgery. A retrospective clinical study was conducted from a prospective database. Eighty-four patients eligible for spine surgery were recruited. Ultrasound was used to localize the intercostal, rectus abdominis, and internal oblique and psoas muscles if pedicle screw placement was performed at T3 to L1. After the operation, patients were examined for any new neurological deficits related to this procedure, and computed tomography was performed to check screw position if indicated. Four to 22 pedicle screws were used for spinal fixation. The threshold of stimulus to obtain a compound muscle action potential ranged from 1.29 to >20mA during PSS. Six of our patients sustained new postoperative deficits, and only one case was related directly to pedicel screw misplacement. Loss of motor evoked potential (MEP) over both the lower limbs was noted during pedicle screw placement, and the stimulus threshold during PSS were 1.29mA at the left T9 and 3.8mA at the right T5 level. MEP remained absent at the end of surgery despite removal of those two screws. The patient woke with significant weakness in both lower limbs (muscle power 0/0) and voiding difficulty. Fortunately, he regained walking ability 4.5months later after intensive rehabilitation therapy.

Localization of the cricothyroid muscle under ultrasound guidance for vagal nerve mapping.

During surgical removal of tumors of the skull base or cerebellopontine angle with brainstem compression, the vagus nerve is at a high risk for injury that can result in permanent or transient swallowing and speech dysfunction. Intramuscular recording of cricothyroid muscle can be used for vagal nerve mapping during intraoperative neurophysiologic monitoring so as to prevent the above complications. However, it is a small muscle that lies beneath the strap muscles over the anterior neck and is not easily accessible by a blind approach. Here, we present a case in which cricothyroid muscle was identified for precise electrode placement under ultrasound guidance during preparation for intraoperative monitoring. We concluded that localization of the cricothyroid muscle by ultrasonography proved to be a feasible and easy technique, and the compound muscle action potential recorded by this approach is clearly recognizable during intraoperative vagal nerve mapping.

Fluorescence-assisted visualization of facial nerve during mastoidectomy: A novel technique for preventing iatrogenic facial paralysis.

OBJECTIVE: Mastoidectomy can be risky due to the chance of iatrogenic facial nerve dysfunction. Avoiding injuries to the mastoid segment of the facial nerve is mandatory when drilling the bone. With advancements in intraoperative near-infrared indocyanine green (ICG) video angiography, we describe the application of a novel fluorescent guidance technique during mastoidectomies to identify the facial canal with safety. METHODS: Mastoidectomies were performed as the key step in the presigmoid, petrosal or translabyrinthine approaches in 16 patients with different pathologies located at the cerebellopontine angle or petroclival region. After the facial canal was drilled to paper thin, ICG was injected via the central venous catheter. Compared with the dark bony portion, the vessels inside the vasa nervorum were highlighted as a result. The fluorescence guides the operator through the course of the facial nerve and facilitates opening of the internal auditory canal and the dissection of tumors. RESULTS: All 16 facial nerves were recognized during mastoidectomies under fluorescence guidance for varied periods of enhancing time (range, 23-50s). In all, one to four attempts after repeated drilling works to enhance the facial nerve were required before these nerves could be clearly seen. The tumor resection procedure yielded the following results: grossly total removal in seven patients, near total removal in five, and subtotal removal in three. Complete obliteration of a giant vertebral artery aneurysm in one patient was seen in the follow-up angiogram. The post-mastoidectomy facial nerve function, examined by triggered EMG, was preserved in all 16 patients, and no patients had postoperative facial palsy worse than House-Brackmann grade IV after 6 months of follow-up. CONCLUSION: With this novel technique, the course of the facial nerve can be confirmed during mastoidectomy, which reduces the possibility of iatrogenic facial nerve dysfunction. This fluorescence technique is especially helpful in establishing confidence and shortening the learning curve for beginners at mastoidectomies.

Cognitive and epilepsy outcomes after epilepsy surgery caused by focal cortical dysplasia in children: early intervention maybe better.

BACKGROUND: Focal cortical dysplasia (FCD) is a specific malformation of cortical development harboring intrinsic epileptogenicity, and most of the patients develop drug-resistant epilepsy in early childhood. The detrimental effects of early and frequent seizures on cognitive function in children are significant clinical issues. In this study, we evaluate the effects of early surgical intervention of FCD on epilepsy outcome and cognitive development. METHODS: From 2006 to 2013, 30 children younger than 18 years old underwent resective surgery for FCDs at Taipei Veterans General Hospital. The mean age at surgery was 10.0 years (range 1.7 to 17.6 years). There were 21 boys and 9 girls. In this retrospective clinical study, seizure outcome, cognitive function, and quality of life were evaluated. To evaluate the effects to outcomes on early interventions, the patients were categorized into four groups according to age of seizure onset, duration of seizure before surgery, and severity of cognitive deficits. RESULTS: Eleven of 22 (50 %) patients demonstrated developmental delay preoperatively. The Engel seizure outcome achievements were class I in 21 (70 %), class II in 2 (7 %), class III in 6 (20 %), and class IV in 1 (3 %) patients. The locations of FCDs resected were in the frontal lobe in 18 cases, temporal lobe in 7, parietal lobe in 2, and in bilobes including frontoparietal lobe in 2 and parieto-occipital lobes in 1. Eight cases that had FCDs involved in the rolandic cortex presented hemiparesis before surgical resection. Motor function in four of them improved after operation. The histopathological types of FCDs were type Ia in 1, type Ib in 7, type IIa in 7, type IIb in 12, and type III in 3 patients. FCDs were completely resected in 20 patients. Eighteen (90 %) of them were seizure free (p < 0.001) with three patients that received more than one surgery to accomplish complete resection. The patients who had early seizure onset, no significant cognitive function deficit, and early surgical intervention with complete resection in less than 2 years of seizure duration showed best outcomes on seizure control, cognitive function, and quality of life. CONCLUSION: Delay in cognitive development and poor quality of life is common in children treated for FCDs. Early surgical intervention and complete resection of the lesion help for a better seizure control, cognitive function development, and quality of life. FCDs involved eloquent cortex may not prohibit complete resection for better outcomes.

Intraoperative brain mapping to identify corticospinal projections during resective epilepsy surgery in children with congenital hemiparesis.

PURPOSE: The purpose of the study is to determine corticospinal organization using intraoperative neurophysiologic monitoring (IONM) during resective epilepsy surgery for patients with congenital hemiparesis and intractable epilepsy. METHODS: Ten patients, aged 3-17, with intractable epilepsy underwent resective surgery. Transcranial stimulation (TCS) was achieved using a pair of cork screws at Cz and C3/C4, respectively. A 1 × 4 stimulating electrode strip was placed on the presumed motor cortex of the affected hemisphere for direct cortical stimulation (DCS) after craniotomy. Multipulse TCS and DCS train stimulation was delivered, with simultaneous recordings from bilateral abductor pollicis brevis and abductor halluces, to determine the corticospinal projection pattern of the paretic limbs. RESULTS: The above mapping techniques revealed ipsilateral corticospinal projections from the contralesional hemisphere to target muscles in the paretic limbs in three patients, projections from both hemispheres to target muscles in three, and preserved crossed projections from the affected hemisphere in four. Nine patients were seizure free after surgery. Five had unchanged postoperative functional status, and three showed minimally improved use of the paretic hand. Two developed new motor deficits after surgery, which may have been due to a premotor syndrome in one patient, since it completely resolved within 2 weeks. The other experienced increased weakness of the paretic lower limb because a small part of the eloquent cortex was removed for better seizure control. CONCLUSIONS: Using IONM to define the corticospinal projection pattern is a valuable technique that can potentially replace preoperative fMRI and transcranial magnetic stimulation in resective epilepsy surgery, particularly for younger patients.

Brainstem auditory evoked potential monitoring and neuro-endoscopy: two tools to ensure hearing preservation and surgical success during microvascular decompression.

BACKGROUND: The effectiveness of microvascular decompression (MVD) has made trigeminal neuralgia (TN), hemifacial spasm (HFS), glossopharyngeal neuralgia, and other cranial nerve rhizopathy diseases treatable by surgery. To ensure hearing preservation and surgical success, we have presented our experience in the application of brainstem auditory evoked potential (BAEP) monitoring and neuro-endoscopy during MVD. METHODS: From July 2007 to October 2012, a total of 93 patients in our institution received MVD for cranial nerve rhizopathies. Among these patients, 43 had both BAEP monitoring and endoscope-assisted microsurgery for their MVD. None of the patients had undergone previous surgical treatment. Postoperative outcomes were assessed based on the medical records and clinical follow-up. RESULTS: This study included 32 women and 11 men. There were 36 HFS cases and seven TN cases, and the median patient age at the time of MVD was 48 years. The median duration of symptoms before MVD was 4.2 years, and the median follow-up duration was 3.5 years (range 1.5 months-5 years). All of the patients had either immediate or delayed complete relief from the symptoms after MVD. One TN patient underwent gamma knife radiosurgery 3 years after MVD, and two HFS cases had recurrent slight spasms, which warranted no further treatment. There was no surgical mortality. The major complications included one HFS patient with delayed and permanent hearing loss and facial palsy, which occurred 1 week after MVD. The surgical success rate was 100%, and the hearing complication rate was 2%. CONCLUSION: The results of this retrospective study emphasized the importance of BAEP monitoring and neuro-endoscopy during MVD. It is well known that BAEP monitoring can preserve hearing function, and the endoscope offers neurosurgeons a second look to identify the nerve root entry zone and confirms the position of the Teflon felt. These two tools are especially useful in difficult cases.

Clinical manifestation and neurosurgical intervention of encephalocraniocutaneous lipomatosis--a case report and review of the literature.

INTRODUCTION: Currently, there are only a few reported cases of symptomatic or asymptomatic subpial (intramedullary) spinal lipoma, and therefore no guidelines are available to indicate surgery. These lesions are infrequently associated with spina bifida. CASE REPORT: Herein, we provide our experience in the neurosurgical intervention of compressive myeloradiculopathy for encephalocraniocutaneous lipomatosis (ECCL). The patient initially presented with bilateral upper hand paralysis, then regained muscle power after surgery and during 1 year of follow-up. We discuss the neurosurgical indications and intervention, imaging studies, other associated symptoms, and the pathogenesis of ECCL in an infant.

Neuropsychological functions and quality of life in survived patients with intracranial germ cell tumors after treatment.

BACKGROUND: The notable survival chances of intracranial germ cell tumors (icGCTs) lead to a rising concern over long-term neurocognitive outcome. Yet, prior evidence related to this issue fails to provide a comprehensive examination of the effects of tumor location and radiotherapy. We attempt to explore their impacts on the neuropsychological functions and life quality in children with icGCT after multimodality treatments. METHODS: A retrospective review of 56 patients diagnosed with icGCTs at age <20 and treated at the Taipei Veterans General Hospital was provided. Intelligence, memory, visual organization, attention, and executive function were assessed by neurocognitive tests; adaptation to life, emotional and behavioral changes, interpersonal relationships, and impact on the family were evaluated by parent-report instruments. Effects of tumor locations (germinomas and nongerminomatous malignant germ cell tumors in the pineal, suprasellar, and basal ganglia) and irradiation on these measurements were examined. RESULTS: Patients with tumors in the basal ganglia region had lower full-scale IQs than those with tumors in the pineal or suprasellar regions. Subscores of intelligence scale and short-term retention of verbal and visual stimuli showed evident group differences, as did the quality of life and adaptive skills, particularly in psychosocial domains. Patients treated with whole-ventricular irradiation had better outcomes. Extensive irradiation field and high irradiation dosage influenced intellectual functions, concept crystallization, executive function, and memory. CONCLUSIONS: Tumor location and irradiation field/dosage appear to be the crucial factors related to certain neuropsychological, emotional, and behavioral dysfunctions that in turn alter the quality of life in children with icGCTs who survive after treatment.

Ultrasound-guided perineural steroid injection to treat intractable pain due to sciatic nerve injury.

PURPOSE: Sciatic neuropathy is a rare but serious complication of cardiac surgery. Neuropathic pain following nerve injury can be severely debilitating and largely resistant to treatment. We present a case of this complication where ultrasound-guided perineural steroid injection at the site of the sciatic nerve injury provided excellent pain relief and facilitated subsequent rehabilitation. CLINICAL FEATURES: A 17-yr-old boy developed bilateral sciatic neuropathy after a nine-hour cardiac surgical procedure in the supine position, resulting in debilitating dysesthesia refractory to neuropathic pain therapies and leading to severe functional limitation. With magnetic resonance imaging of the lower extremities, the location of the lesion was determined to be from the level of the superior gemellus to the level of the quadratus femoris. An ultrasound-guided injection of triamcinolone 20 mg and lidocaine 40 mg around both sciatic nerves at the level of the lesion was administered two months after the surgery, and the pain score (rated on a scale 0-10) at rest decreased from 9-10 to 1 two weeks after the injection. CONCLUSIONS: There are a limited number of reports in the literature on sciatic nerve injuries associated with cardiac surgery. This case illustrates the efficacy of ultrasound-guided steroid injection around sciatic nerves at the level of superior gemellus in treating our patient's neuropathic pain.

Telovelar approach for choroid plexus papilloma in the foramen of Luschka: a safe way using a neuromonitor.

BACKGROUND: Tumors located in the 4th ventricle are always challenging to neurosurgeons, especially tumors that extend to the cerebellopontine (CP) angle by the foramen of Luschka. Recent advances in microsurgical technique, including the neuromonitor and brainstem mapping, facilitate the surgical resection of tumors located in the foramen of Luschka. Herein, we present the use of the telovelar approach to access a choroid plexus papilloma within the right foramen of Luschka. CASE PRESENTATION: A 28-year-old female presented with a history of sudden onset pulsatile headache and syncope twice without prodrome. The brain MRI revealed a 4th ventricular tumor deviated to the right foramen of Luschka and extending to the CP angle, 2.2 cm in diameter. There was no secondary hydrocephalus due to the patent foramen of Magendie and left foramen of Luschka. The patient underwent suboccipital craniotomy and C1 laminectomy with a telovelar approach. The right tonsil was elevated and teal chloride was incised from the foramen of Magendie to the telovelar junction. The tumor was centrally decompressed, and the margin was gently dissected from the brainstem and cerebellum peduncles. Functions of the facial, cochlear, glossopharyngeal, vagus, and hypoglossal nerves and nuclei were monitored. Mapping of the facial nucleus, ambiguous nucleus, and hypoglossal nucleus was also done. Total tumor removal was achieved and the histology showed choroid plexus papilloma. No functional neurological disorientation was observed after surgery. CONCLUSION: The report demonstrated a safe and effective surgical approach to the foramen of Luschka. The approach yielded a better view of the foramen of Luschka laterally, and up to the middle cerebellar peduncle superiorly. Also, it minimized neural damage, and preserved the function of the cranial nerves and nucleus.

Bilateral sciatic neuropathy as a complication of craniotomy performed in the sitting position: localization of nerve injury by using magnetic resonance imaging.

INTRODUCTION: Sciatic neuropathy is a rare but serious complication following surgery performed in the sitting position. METHODS: We report a case of a 12-year-old boy who developed bilateral sciatic neuropathy after a 9-h-long craniotomy while in the sitting position. RESULTS: Magnetic resonance imaging for the lower extremities revealed bilateral swelling of the sciatic nerves near the ischial tuberosities. CONCLUSION: A heightened awareness of sciatic nerve injury during prolonged surgery in the sitting position may make early diagnosis possible and allow prevention of further neurologic injury.

Corpus callosotomy in children.

INTRODUCTION: For children of medical resistant epilepsy without resectable epileptogenic zone, corpus callosotomy and vagus nerve stimulation (VNS) therapy are the two commonly used palliative epilepsy surgeries that can be considered. Although their routes and mechanisms to control epilepsy are different, both surgeries have shown their efficacy in selected candidates. The most common candidates for palliative surgery are in infants and children with organic encephalopathic types of epilepsy including infantile spasms/West syndrome, Lennox-Gastaut syndrome (LGS), severe epilepsy with multiple independent spike foci (SE-MISF) and selected symptomatic partial epilepsy to relief seizures and to stabilize co morbidities (Hirsch and Arzimanoglou, Revue Neurologique [Hirsch E and Arzimanoglou A, Rev Neurol (Paris). 160 Spec No 1:5S210-S219, (2004); Ohtahara S and Yamatogi Y, J Clin Neurophysiol 20(6):398-407, (2003); Wheless JW and Epilepsia 45(Suppl 5):17-22, (2004); Trevathan E, J Child Neurol 17 Suppl 2:2S9-2S22, (2002)]. DISCUSSION: Callosotomy is a major and destructive but affordable surgical procedure as compare to the relative simple but costly extracranial procedure of VNS therapy. However, callosotomy is a safe and effective palliative operation in neurosurgeons familiar with the surgical procedure. Equipments for callosotomy can be as simple as headlight and binocular loupes, self-retention brain retractor, bipolar cauterization, and simple microinstruments.