Hideki Ogiwara

Long-term Follow-up of Pediatric Benign Cerebellar Astrocytomas

BACKGROUND The long-term prognosis of cerebellar astrocytomas needs to be reviewed. OBJECTIVE To elucidate the factors influencing tumor recurrence or progression and to determine how long these patient with cerebellar astrocytomas require surveillance with neuroimaging. METHODS A retrospective review of 101 children surgically treated for a cerebellar astrocytoma and followed up for > 10 years was performed. RESULTS Mean follow-up was 18.4 years. Total resection confirmed by postoperative imaging was performed in 51 patients (50.5%; group A). Twenty-three patients (22.8%) had surgical total resection; however, equivocal residual tumor was found on postoperative imaging (group B). Subtotal resection leaving a portion of brainstem or cerebellar peduncle was performed in 27 patients (26.7; group C). Of these 50 residual tumors, 16 (32%) showed spontaneous regression and 8 (16%) showed arrested growth. Radiographic recurrence or progression was noted in 29 patients (28.7%). Only 3 of 51 patients (5.9%) of group A with total resection had recurrence, whereas 26 of 50 residual tumors (52%; groups B and C) progressed. The only factor affecting recurrence or progression by multivariate analysis was the extent of surgical resection. All tumor recurrence or progression except for 1 (96.6%) occurred within 8 years from the original surgery (range, 2-132 months). CONCLUSIONS Overall prognosis of cerebellar astrocytomas is good; the 10-year survival rate was 100% and recurrence- or progression-free rate was 71.3% in our cohort. Almost half of residual tumors showed spontaneous regression or arrested growth in the long term. Eight to 10 years is considered to be a reasonable follow-up period by neuroimaging.

Choroid plexus tumors in pediatric patients.

Abstract Objective. Choroid plexus tumors are rare intraventricular tumors, accounting for less than 1% of all intracranial tumors and 2–4% of brain tumors in children. The authors present their experience in the management of these lesions, and a review of the literature is performed. Methods. We retrospectively analyzed the outcome of pediatric patients with choroid plexus tumors treated with surgical resection. The patients’ charts were reviewed for demographic data, clinical presentation, surgical therapy and follow-up. Results. This study involves 18 consecutive choroid plexus tumors: 14 papillomas, 2 atypical papillomas and 2 carcinomas. The tumor was located in the lateral ventricles (12), the fourth ventricle (4) and the third ventricle (2). The mean age at presentation was 4.6 years. Surgical resection was performed in all cases and no patients died perioperatively. Survival rate of papilloma patients was 100% without evidence of recurrent disease (mean follow-up for 73 months). Survival rate of carcinoma patients was 50% (mean follow-up for 23.5 months). One carcinoma patient died of disseminated disease 13 months after surgery. The functional outcome in long-term survivors after papilloma surgery was excellent. Postoperative extraventricular drainage (EVD) was performed in 12 patients. Five patients (27.8%) had persistent hydrocephalus after tumor resection and required a ventriculoperitoneal shunt. Conclusion. Choroid plexus papilloma is a surgically curable disease. Postoperative EVD was considered effective in lowering the rate of shunt requirement through releasing the blood-tinged CSF and small particles of tumor residue.

New classification of spinal lipomas based on embryonic stage

OBJECTIVE Spinal lipomas are generally thought to occur as a result of failed primary neurulation. However, some clinical features cannot be explained by this theory. The authors propose a novel classification of spinal lipomas based on embryonic changes seen during primary and secondary neurulation. METHODS A total of 677 patients with occult spinal dysraphism underwent 699 surgeries between August 2002 and May 2015 at the National Center for Child Health and Development and Tokyo Metropolitan Childrens Medical Center. This group of patients had 378 spinal lipomas, including 119 conus spinal lipomas, 27 lipomyelomeningoceles, and 232 filum lipomas, which the authors classified into 4 types based on neural tube formation during embryonic development. Type 1 is defined as pure primary neurulation failure; Type 2 ranges from primary to secondary neurulation failure; Type 3 consists of secondary neurulation failure (early phase); and Type 4 is defined as secondary neurulation failure (late phase). The authors also review embryogenesis in secondary neurulation and analyze the clinical utility of the new classification. RESULTS There were 55 Type 1 spinal lipomas, 29 Type 2, 62 Type 3, and 232 Type 4. All filum lipomas fell into the Type 4 spinal lipoma category. Association with anorectal and/or sacral anomalies was seen in none of the Type 1 cases, 15 (52%) of Type 2, 35 (56%) of Type 3, and 31 (13%) of Type 4. Urogenital anomalies were observed in none of the Type 1 or Type 2 cases, 1 (2%) of Type 3, and 28 (12%) of Type 4. Anomaly syndromes were present in none of the Type 1 cases, 6 (21%) of Type 2, 3 (5%) of Type 3, and 16 (7%) of Type 4. Associated anomalies or anomaly syndromes were clearly observed only for Type 2-4 spinal lipomas encompassing failed secondary neurulation. Radical resection was feasible for Type 1 spinal lipomas. CONCLUSIONS Secondary neurulation of the spinal cord gives rise to the conus medullaris and filum terminale, which are often involved in spinal lipomas. Formation of spinal lipomas seems to be a continuous process overlapping primary and secondary neurulation in some cases. Association with other anomalies was higher in Type 2-4 spinal lipomas, which included failed secondary neurulation, than in Type 1 lipomas, with failed primary neurulation. On the other hand, radical resection was indicated for Type 1, but not for Type 2, spinal lipomas. The new classification of spinal lipomas based on embryonic stage has the potential for clinical use and agrees well with both clinical and surgical findings. The classification proposed here is still preliminary. Further studies and verification are necessary to establish its clinical utility.

Endoscopic fenestrations for suprasellar arachnoid cysts

OBJECT The endoscopic treatment of a suprasellar arachnoid cyst (SAC) consists mainly of ventriculocystostomy (VC) and ventriculocystocisternostomy (VCC). However, the most appropriate treatment for these cysts has not been fully determined yet. The authors report on the effectiveness of endoscopic VC for SACs communicating with the basal cisterns, which is demonstrated by preoperative CT cisternography. METHODS The authors retrospectively analyzed the surgical results of patients with an SAC treated using endoscopic fenestration. The patient charts were reviewed for demographic data, clinical presentations, surgical therapies, and clinical outcomes. RESULTS Six consecutive patients with SAC were surgically treated using endoscopic fenestration (VC or VCC) between March 2004 and February 2011. The mean age was 18.5 months (range 5 days to 37 months). Five patients were previously untreated, and 1 patient had previously undergone ventriculoperitoneal shunt placement. Five patients underwent preoperative CT cisternography, and communication between the SAC and the basal cisterns was demonstrated in 3 patients, very slight communication in 1, and no communication in 1. Four patients, including the 3 with communication between the SAC and basal cisterns, underwent VC. Two patients with very slight or no communication underwent VCC. In all patients the SAC decreased in size and hydrocephalus improved postoperatively. Five patients (3 treated with VC and 2 with VCC [83%]) have been stable without reoperation (mean follow-up 32.7 months). All 3 patients with an SAC communicating with the basal cisterns have been stable without reoperation following VC. CONCLUSIONS Preoperative cisternography may be useful for selecting the optimal endoscopic treatment method for SAC. If an SAC communicates with the basal cisterns, a VC could be an effective, safe, and simpler treatment option.

Obliteration of the choroid plexus after endoscopic coagulation

OBJECT Endoscopic choroid plexus coagulation (CPC) with or without endoscopic third ventriculostomy (ETV) has been shown to be effective for selected patients with hydrocephalus. However, whether the effect of the coagulation is temporary and the choroid plexus regenerates or can be obliterated has remained largely unknown. The authors evaluate the effectiveness of CPC and report 3 cases of obliteration demonstrated by direct endoscopic observation. METHODS The authors retrospectively analyzed the surgical results of patients with hydrocephalus primarily treated by CPC with or without ETV. Charts were reviewed for demographic data, clinical presentations, surgical therapies, and clinical outcomes. RESULTS Eighteen patients with hydrocephalus were surgically treated using endoscopic CPC between July 2002 and July 2012. In 12 patients, ETV was concurrently performed. The etiology of hydrocephalus was posthemorrhagic in 5 patients, myelomeningocele in 3, postmeningitis in 2, congenital aqueductal stenosis in 1, hydranencephaly in 1, porencephaly in 1, and idiopathic in 5. The mean age at surgery was 8 months (range 0.3-24 months). The mean follow-up was 64 months. In 9 cases (50%), control of hydrocephalus was successful and the patients did not require further surgeries. In 9 patients (50%), treatment failed. Of these, 3 patients underwent repeat ETV 2, 3, and 38 months after the initial surgery. Endoscopic observation of the previous coagulation site revealed no regeneration of the choroid plexus in 2 patients, who underwent repeat ETV 2 and 3 months after CPC. In 1 patient who underwent repeat ETV 38 months after CPC, no regeneration of the choroid plexus, except for that in the proximity of the foramen of Monro, was observed. CONCLUSIONS Endoscopic CPC with or without ETV can be a safe and effective treatment alternative to shunt placement in infantile hydrocephalus. Obliteration of the choroid plexus can persist in the relatively long term following CPC, which may contribute to the long-term control of hydrocephalus in successful cases.

Flexible endoscopy for management of intraventricular brain tumors in patients with small ventricles

OBJECT Endoscopic surgery is generally withheld in patients with small ventricles due to difficulties in ventricular cannulation and intraventricular manipulation. The effectiveness of flexible endoscopy for management of intraventricular brain tumors in patients with small ventricles was evaluated. METHODS Forty-five patients who underwent endoscopic surgery with a flexible endoscope for intraventricular brain tumors were divided into small-ventricle and ventriculomegaly groups according to the frontal and occipital horn ratio (FOR). Retrospective review of these cases was performed and achievement of surgical goals and morbidity were assessed. RESULTS Among the 45 patients, there were 14 with small ventricles and 31 with ventriculomegaly. In the smallventricle group, targeted tumors were located in the suprasellar region in 12 patients and in the pineal region in 2. In the ventriculomegaly group, tumors were located in the pineal region in 15 patients, in the suprasellar region in 9, in the lateral ventricle in 4, in the midbrain in 2, and in the fourth ventricle in 1. In the small-ventricle group, ventricular cannulation was successful and the surgical goals were accomplished in all patients. In ventriculomegaly group, sampling of the tumor was not diagnostic due to intraoperative hemorrhage in 1 patient. There were no significant differences in the rate of achieving the surgical goals or the morbidity between the 2 groups. CONCLUSIONS Endoscopic surgery using a flexible endoscope is useful for management of intraventricular brain tumors in patients with small ventricles. A flexible endoscope allows excellent maneuverability in introducing the device into the lateral ventricle and manipulating through small ventricles.

Second-look surgery for intracranial germ cell tumors.

BACKGROUND The role of second-look surgery in intracranial germ cell tumors (GCTs) needs to be reviewed. OBJECTIVE To present our experience of second-look surgery in patients with intracranial GCTs who showed less than complete response despite normalizing or decreasing tumor markers after chemotherapy. METHODS Retrospective review of 7 patients who underwent second-look surgery for an intracranial GCT was performed. RESULTS Of 23 consecutive patients with newly diagnosed intracranial GCTs treated between August 2003 and August 2013, 7 patients (30%) underwent second-look surgery. The mean age was 9.4 years. The initial diagnoses were mixed germ cell tumor in 5 and immature teratoma in 2. Second-look surgery was performed after 1 to 3 courses of chemotherapy. Magnetic resonance imaging at the surgery demonstrated increasing residual tumor in 4 and stable residual tumor in 3. Tumor markers were normalized in 5 and nearly normalized in 2. Gross total resection was achieved in all patients. Histopathology at second-look surgery revealed mature teratoma in 5, fibrosis with atypical cells in 1, and fibrosis in 1. All patients subsequently underwent additional chemoradiation therapy according to the initial diagnosis. All patients are alive with no evidence of recurrence, with a mean follow-up of 48 months. CONCLUSION Second-look surgery plays an important role in the treatment of intracranial GCTs. Surgery may be encouraged at a relatively early phase after chemotherapy when the residual tumor increases or does not change size despite normalized or nearly normalized tumor markers in order to achieve complete resection and improve outcome.

Subependymal giant cell astrocytoma with intratumoral hemorrhage

The authors report on 2 cases of subependymal giant cell astrocytoma (SEGA) with intratumoral hemorrhage causing acute hydrocephalus, necessitating emergent resection of the tumor. They review the literature and present their insights on the management of SEGA showing growth on serial imaging. Intratumoral hemorrhage causing acute hydrocephalus can occur not only in the pediatric ages but also in the early 20s in patients with SEGA. Awareness of this sequela is considered to be important in addressing surgical timing. The authors suggest early resection of the lesions when the evidence of growth has been confirmed, to prevent possible morbidity and mortality.

Pudendal afferents mapping in posterior sacral rhizotomies.

BACKGROUND The effectiveness of pudendal afferents mapping in posterior sacral rhizotomies needs to be reviewed. OBJECTIVE To evaluate the effectiveness of pudendal afferents mapping for both the dorsal penile or clitoral nerve and the inferior anal nerve to decrease the risk of postoperative bowel and bladder dysfunction when the sacral nerve roots are candidates for rhizotomies. METHODS A retrospective review of 101 Asian children who underwent functional posterior rhizotomies with pudendal afferents mapping for spastic paresis was performed. RESULTS Pudendal mapping was successful in 75 of 81 patients. The highest activity of afferent fibers of the dorsal penile or clitoral nerve was demonstrated at the S1 roots in 13.3%, at the S2 in 79.3%, and at the S3-5 in 7.3%. Considerable activity of the dorsal penile or clitoral nerve was recorded at 40% of the S1 roots, at 99.3% of the S2 roots, and at 52% of the S3-5 roots. The highest activity of afferent fibers of the inferior anal nerve was demonstrated at S2 roots in 42% and at S3-5 roots in 58%. Considerable activity of the inferior anal nerve was recorded at 10.7% of S1 roots, at 89.3% of S2 roots, and at 76.7% of S3-5 roots. The pathological S1 roots were divided into 3 to 4 rootlets, and the rootlets with significant afferent activity were preserved. None of the 75 patients experienced long-term bowel or bladder complications. CONCLUSION Pudendal afferent mapping identified the sacral rootlets involved with genital and anal sensation. The preservation of such rootlets in sacral rhizotomies is considered to be important for minimizing postoperative bladder and bowel dysfunction.

Diffuse postoperative cerebellar swelling in medulloblastoma: report of two cases

BackgroundWe report two cases of diffuse cerebellar swelling with upward transtentorial herniation following medulloblastoma resection. We present our insight for managing medulloblastoma with aggressive clinical behavior.Review summaryCase 1 is a 32-month-old boy. Magnetic resonance imaging (MRI) revealed fourth ventricular mass with diffuse leptomeningeal metastasis. He underwent gross total resectioning of the tumor and histopathology revealed a large cell medulloblastoma. A ventriculoperitoneal shunt was placed on the 25th postoperative day. Ten days after he developed lethargy, and MRI showed diffuse cerebellar swelling with upward herniation. He underwent emergent posterior fossa decompression; however, he remained unresponsive since then. Case 2 is a 31-month-old boy. MRI revealed a fourth ventricular mass with diffuse leptomeningeal metastasis. He underwent gross total resection and histopathology was a large cell medulloblastoma. Due to developing ventriculomegaly, extraventricular drainage was reinserted on the 11th postoperative day. Four days after, he developed lethargy and decerebrate posturing. MRI showed diffuse cerebellar swelling with upward herniation. He underwent aggressive posterior fossa decompression. Chemotherapy was started postoperatively. Gradually, his movement of extremities improved. On the 79th postoperative day, he started to follow commands and talk some words. He was discharged to a rehabilitation institute and has continued to improve since then.ConclusionDiffuse cerebellar swelling with upward herniation could occur in patients with aggressive medulloblastoma postoperatively. Our patients had diffuse leptomeningeal dissemination of the tumor at the initial presentation. Close monitoring and prompt diagnosis with earlier surgical posterior fossa decompression and administration of chemotherapy may prevent irreversible neurologic deterioration.