Prevalence of dysphagia following posterior fossa tumor resection: a systematic review and meta­analysis.

OBJECTIVE: Dysphagia is common in individuals who have undergone posterior fossa tumor (PFT) resection and negatively impacts on the individual's quality of life, nutritional status, and overall health. We aimed to quantitatively synthesize data from studies of the prevalence of dysphagia following PFT resection. METHODS: PubMed, Web of Science, the Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Wanfang database, and VIP database were searched for case-control and cross-sectional studies that evaluated the prevalence of dysphagia after PFT surgery. Meta-analyses were performed to determine the prevalence of dysphagia. Subgroup and meta-regression analyses were performed to determine the sources of heterogeneity among the studies. RESULTS: A total of 22 studies were included, involving 20,921 cases. A meta-analysis of the random-effects model showed that the pooled global prevalence of dysphagia following PFT resection was 21.7% (95% confidence interval: 16.9-26.6). The subgroup and meta-regression analyses demonstrated that participant age (P < 0.001), assessment methods (P = 0.004), and geographical region of the study participants (P = 0.001) were sources of heterogeneity among the studies. CONCLUSIONS: Dysphagia has a high prevalence following PFT resection. Individuals with PFTs who are at a high risk for dysphagia should be identified early through screening. Multidisciplinary diagnosis and treatment of dysphagia are required to improve the outcomes in the early stages after PFT resection.

Effects of cognitive-motor intervention for pediatric posterior fossa tumor survivors: results of a pilot study.

The purpose of this prospective pilot study was to evaluate the feasibility and effects of cognitive-motor intervention on the cognitive and motor abilities of pediatric survivors of posterior fossa tumors. The study involved patients aged 7 to 18 years with cognitive deficits who had completed primary treatment for posterior fossa tumors. 25 participants (Mage=11.3 ± 2.93, 64% male; 17 medulloblastoma, 1 ependymoma, 1 desmoplastic medulloblastoma, 6 piloid astrocytoma; 22 in remission (Mmonths =45), 3 in stabilization (Mmonths=49)) were recruited from the Research Institute for Brain Development and Peak Performance. The intervention consisted of two phases with a 3-month break for home training, and a total duration of 6 months. Each phase lasted 7 weeks and included two assessment procedures (pre- and post-intervention) and 10 training sessions over a period of 5 weeks (two 3-hour sessions per week). At baseline and pre- and post-intervention, all participants underwent a battery of cognitive and motor tests. Each training session included gross motor training (GMT), graphomotor training (GT), and cognitive-motor training (CMT). Statistical analysis was performed using the Friedman test for repeated measures and post-hoc Durbin-Conover test. The results indicated significant improvements in visuospatial working memory, visual attention, eye-hand coordination, semantic verbal fluency, auditory-motor synchronization, reaction time, and a decrease in the rate of ataxia. These improvements remained stable even in the absence of direct intervention. The findings demonstrate positive effects and feasibility of the intervention and suggest the need for further research in this area including randomized controlled feasibility studies with a larger sample.

Treatment of hydrocephalus following posterior fossa tumor resection: a multicenter collaboration from the Hydrocephalus Clinical Research Network.

OBJECTIVE: Persistent hydrocephalus following posterior fossa brain tumor (PFBT) resection is a common cause of morbidity in pediatric brain tumor patients, for which the optimal treatment is debated. The purpose of this study was to compare treatment outcomes between VPS and ETV in patients with persistent hydrocephalus following surgical resection of a PFBT. METHODS: A post-hoc analysis was performed of the Hydrocephalus Clinical Research Network (HCRN) prospective observational study evaluating VPS and ETV for pediatric patients. Children who experienced hydrocephalus secondary to PFBT from 2008 to 2021 were included. Primary outcomes were VPS/ETV treatment failure and time-to-failure (TTF). RESULTS: Among 241 patients, the VPS (183) and ETV (58) groups were similar in age, extent of tumor resection, and preoperative ETV Success Score. There was no difference in overall treatment failure between VPS and ETV (33.9% vs 31.0%, p = 0.751). However, mean TTF was shorter for ETV than VPS (0.45 years vs 1.30 years, p = 0.001). While major complication profiles were similar, compared to VPS, ETV patients had relatively higher incidence of minor CSF leak (10.3% vs. 1.1%, p = 0.003) and pseudomeningocele (12.1% vs 3.3%, p = 0.02). No ETV failures were identified beyond 3 years, while shunt failures occurred beyond 5 years. Shunt infections occurred in 5.5% of the VPS cohort. CONCLUSIONS: ETV and VPS offer similar overall success rates for PFBT-related postoperative hydrocephalus. ETV failure occurs earlier, while susceptibility to VPS failure persists beyond 5 years. Tumor histology and grade may be considered when selecting the optimal means of CSF diversion.

Diencephalic syndrome-like presentation of brainstem tumor: a series case-based review.

PURPOSE: Russel described a rare clinical entity known as diencephalic syndrome (DS) in 1951, which was traditionally caused by a neoplasm in the hypothalamic-optic chiasmatic region. DS is characterized by severe emaciation despite adequate or slightly reduced caloric intake, locomotor hyperactivity, euphoria and other minor features. Current evidence suggests that a rare population of children with a similar phenotype may have their tumor located in the posterior fossa instead, defining the DS-like presentation, a rare entity with few cases reported in the literature. METHODS: A thorough search of three databases (PubMed, Ovid Medline, and Ovid Embase) was conducted to identify relevant papers reporting children with DS associated with brainstem tumors. To our knowledge, only seven cases have been documented in the literature. Moreover, we present four of our own cases, focusing on the unusual clinical presentation, the diagnosis process, and the lag time between the initial symptoms and the definitive diagnosis. RESULTS: In this review, the mean lag time between the onset of symptoms and diagnosis was 20.9 months (median: 16 months; range: 1.5-72 months), whereas in our series of cases, the time was 32.5 months (median: 33 months; range: 7-57 months). CONCLUSION: Despite recent significant advances in neuro-oncology diagnostic tools, this mean lag time did not improve when compared with the previous literature review from 1976. Throughout these data, we aim to raise awareness in the hopes of detecting intracranial neoplasms earlier in cases of children with profound emaciation of unknown cause.

Occipital interhemispheric transtentorial approach in pediatric patients for lesions of the superomedial cerebellum: operative findings and results.

BACKGROUND: The occipital interhemispheric transtentorial (OITT) approach is frequently used for accessing the pineal region. There are scarce reports of using the OITT to access superior cerebellar lesions. This approach affords the patient several advantages over traditional posterior fossa approaches. PURPOSE: This study is to describe and evaluate clinical outcomes in a single surgeon case series of the OITT approach for pediatric patients with lesions of the superior cerebellum. METHODS: All pediatric patients who underwent an OITT craniotomy for a superior cerebellar lesion by a single surgeon over a 5-year period were included in this retrospective analysis. Patient demographics and clinical data were collected. RESULTS: Thirteen pediatric patients were identified. Cases included twelve tumors and one arteriovenous malformation. Gross total resection was achieved in 92% of cases. No patients developed posterior fossa syndrome. Two patients had transient homonymous hemianopsia that resolved by 1 month post-operatively. There were no permanent neurological deficits. CONCLUSION: For superomedial cerebellar lesions presenting to the tentorial surface of the superior cerebellum in patients with normal to steep tentorial angles, the OITT approach is effective and safe. This approach has a low risk of posterior fossa syndrome and permanent visual deficits when applied appropriately. Patient selection is critical for maximizing the advantages of the OITT for superior cerebellar lesions.

Perioperative external ventricular drainage vs. no-EVD strategy in pediatric posterior fossa tumors-pilot study results.

INTRODUCTION: Pediatric brain tumors of the posterior fossa often present with occlusive hydrocephalus. Endoscopic third ventriculostomy (ETV) or ventriculoperitoneal shunting (VPS) has been established for definite hydrocephalus treatment. The aim of the study was to analyze the impact and safety of perioperative temporary external ventricular CSF drainage (EVD) placement on postoperative hydrocephalus outcome compared to a no-EVD strategy. PATIENTS AND METHODS: In a prospective database, 36 posterior fossa tumor patients of 2-18 years were included with a follow-up of 1 year. Fifty-eight percent presented with preoperative hydrocephalus. Patients were assigned to non-hydrocephalus group: group I (n = 15) and to preoperative hydrocephalus, group IIa with EVD placement (n = 9), and group IIb without EVD (n = 12). RESULTS: Median age of patients was 8.1 years (range 3.17 to 16.58 years). One-third of 21 hydrocephalus patients required ETV or VPS (n = 7). Occurrence of de novo hydrocephalus in group I after surgery was not observed in our cohort. Age and histology were no confounding factor for EVD placement between group IIa and IIb (p = 0.34). The use of EVD did not result in better control of hydrocephalus compared to no-EVD patients considering pre- and postoperative MRI ventricular indices (p = 0.4). Perioperative placement of an EVD resulted in a threefold risk for subsequent VPS or ETV (group IIa 55.5% vs group IIb 16.6%): relative risk for EVD patients compared to no-EVD patients with hydrocephalus was 3.3 (CI = 1.06-13.43, p = 0.09). CONCLUSION: Perioperative EVD placement appears to harbor a threefold relative risk of requiring subsequent permanent CSF diversion in children above 2 years. EVD was not more effective to control ventricular enlargement compared to tumor removal alone. The no-EVD strategy was safe and did not result in postoperative complications. Thus, to evaluate potential adverse effects on hydrocephalus outcome by EVD placement, a prospective study is warranted to falsify the results.

Phonological Verbal Fluency Test for Russian-Speaking Children.

INTRODUCTION: Verbal fluency tasks are mainly used for assessment of verbal fluency and have proven useful for differential diagnosis. The first objective of the study was to provide normative data on phonemic verbal fluency (for letters "Π" [p], "O" [o], "C" [s]) in children population. The second objective of the study was to establish diagnostic validity of the present task and to collect normative data on participants who survived posterior fossa tumor (PFT) and participants with treated hemoblastosis. METHOD: For diagnostics, we used verbal fluency test. The normative sample consisted of 746 participants aged 7-16 years. A linear multiple regression analysis was implemented for each dependent variable with age, gender, disease for all participants and academic achievement as predictors in normative sample. The performance of 746 healthy participants was compared to the performance of 118 participants who survived PFT and 492 participants who survived hemoblastosis using one-way ANOVA analysis. RESULTS: Healthy children have better verbal fluency than their peers who survived cancer. In the group of healthy children, we assessed the relationship between verbal fluency and school performance. A significant correlation with the "Russian language" subject (r = 0.127; p < 0.001) emerged. In all three groups of children, age and gender turned out to be significant factors that affected the characteristics of verbal fluency. CONCLUSION: Our data will contribute to increasing the accuracy of verbal fluency deficit detection in Russian speakers and will be useful for differential diagnosis of cognitive impairment for children who have survived oncological diseases of various geneses.

Structural damage burden and hypertrophic olivary degeneration in pediatric postoperative cerebellar mutism syndrome.

Cerebellar mutism syndrome (CMS) occurs in one out of four children after posterior fossa tumor surgery, with open questions regarding risk factors, pathophysiology, and prevention strategies. Because of similarities between several cerebellar syndromes, a common pathophysiology with damage to the dentato-thalamo-cortical and dentato-rubro-olivary pathways has been proposed. Hypertrophic olivary degeneration (HOD) is an imaging correlate of cerebellar injury observed for instance in stroke patients. Aim of this study was to investigate whether the occurrence and severity of CMS correlates with the extent of damage to the relevant anatomical structures and whether HOD is a time-dependent postoperative neuroimaging correlate of CMS. We performed a retrospective single center study of CMS patients compared with matched non-CMS controls. CMS occurred in 10 children (13% of the overall cohort) with a median age of 8 years. Dentate nucleus (DN) injury significantly correlated with CMS, and superior cerebellar peduncle (SCP) injury was associated by tendency. HOD was observed as a dynamic neuroimaging phenomenon in the postoperative course and its presence significantly correlated with CMS and DN injury. Children who later developed HOD had an earlier onset and tended to have longer persistence of CMS. These findings can guide surgical measures to protect the DN and SCP during posterior fossa tumor resections and to avoid a high damage burden (i.e., bilateral damage). Development of intraoperative neuromonitoring of the cerebellar efferent pathways as well as improved preoperative risk stratification could help to establish a patient-specific strategy with optimal balance between degree of resection and functional integrity.

Maximizing the subtonsillar transcerebellomedullary approach to suprasellar cistern: how I do it.

BACKGROUND: The subtonsillar transcerebellomedullary approach (STA) has been well established as one of the surgical options to access lesions in the foramen of Luschka. The middle cerebellar peduncle has been defined as the superior limit of this corridor, and tumors extending beyond this landmark were often approached through combined accesses. METHOD: We illustrate the access to the suprasellar cistern, from a purely STA for a large tumor arising from the foramen of Luschka. CONCLUSION: This manuscript demonstrates the STA as a valid alternative for certain tumors of the foramen of Luschka, which extend into crural and suprasellar cisterns.

Risk factors for surgical site infection in pediatric posterior fossa tumors.

PURPOSE: Posterior fossa tumors are the most frequent pediatric solid tumor. Its main treatment is a surgical resection. Being a frequent procedure does not mean that it is exempt from complications, such as surgical site infections (SSI). The main objective of this paper is to study the risk factors associated with SSI following a resection of posterior fossa tumors in a purely pediatric population. METHODS: A retrospective case-control study including all posterior fossa tumor surgeries performed at our hospital between January 2014 and December 2019 was conducted. All patients with a diagnosis of a postoperative SSI have been included as cases, and those who had surgery and no infectious complications have been considered as controls. RESULTS: When analyzing risk factors, we have found that patients with ventriculoperitoneal shunt (VPS) (p = 0.03) or external ventricular drainage (EVD) (p = 0.005) placement had a greater chance of presenting a postoperative surgical site infection. Prolonged operative time (p < 0.001) and cerebrospinal fluid (CSF) leak through the wound (p = 0.002) also caused an increase in the risk of SSI in the postoperative period. A higher hemoglobin value (p = 0.002) would seem to be a preventive factor. CONCLUSIONS: Some strategies that could help to reduce the risk of infections are managing hydrocephalus preferably with endoscopic third ventriculostomy, minimizing the needed operative time to perform the procedure, obtaining an adequate serum hemoglobin level, and avoiding CSF leak through the wound.

Pediatric takotsubo syndrome caused by hydrocephalus after posterior fossa tumor surgery.

Takotsubo syndrome (TTS) can develop after intense physical or emotional stress and is uncommon in children. We report a 2-year-old girl who developed TTS caused by acute hydrocephalus after posterior fossa tumor resection and required mechanical ventilation and administration of vasopressor/inotropic agents. Her cardiac function gradually recovered over the course of 2 weeks. Hydrocephalus after posterior fossa surgery can cause compression of the medulla oblongata, resulting in solitary nucleus dysfunction and TTS, a potentially life-threatening complication.

Surgical management of sporadic hemangioblastomas located in the posterior fossa of brain.

PURPOSE: Hemangioblastomas (HBs) are highly vascular tumors, constituting 2%-3% of central nervous system (CNS) tumors. Surgery is a treatment option for HBs. The purpose of this study was to evaluate the demographic, clinical, and radiological findings of patients with HBs who were operated on via microsurgical technique at our clinic and to determine the findings specific to HBs and evaluate their pathological findings and confirmation. METHODS: We evaluated age, gender, initial complaints and duration of 100 patients (50 female and 50 male patients), presence of cranial nerve deficits, magnetic resonance imaging, data (localization, presence of hydrocephalus, tumor size, enhancement pattern, and cystic and solid component features), resection rates, pathological findings (grade, Ki-67 ratio, and staining results), recurrence, special conditions of patients, and the final status of patients in this study. RESULTS: Mean age was 39.08 ± 14.77 years and 66.7% of the patients presented with cerebellar findings. Five of the cases were located in the brainstem, five were located in the cerebellopontine angle, and two were in the cerebellar cortex. In all patients, gross total resection was performed using arteriovenous malformation repair. CONCLUSIONS: Surgical intervention of small and cystic tumors can be performed safely with en bloc resection along with preoperative detailed imaging, improved microsurgical techniques, and an extensive understanding of anatomical and vascular structures. On the contrary, patients with a brainstem invasion and solid structure present surgical difficulties due to arteriovenous malformation-like vascularizations; therefore, gross total resection is the optimal treatment in HBs.

Predicting dysphagia in children undergoing surgery for posterior fossa tumors.

PURPOSE: Posterior fossa tumors (PFTs) are the most common type of brain tumor in children. Dysphagia is a known complication of PFT resection in children, but data regarding risk factors and clinical course are sparse. METHODS: The records of all children who underwent resection of posterior fossa tumor between April 2007 and May 2017 at our institution were analyzed. Clinical, radiographic, histologic data were gathered. Swallowing function was assessed immediately postoperatively and at 1-year follow-up. RESULTS: A total of 197 patients were included. Forty-three (21.8%) patients developed dysphagia after surgery. Patients who developed dysphagia were younger (4.5 vs. 7.2 years, p < 0.01), were more likely to have brainstem compression (74.4% vs. 57.8%, p < 0.03) or invasion (14.0 vs. 9.7%, p < 0.03), and were more likely to have ependymoma (27.9% vs. 13.6%, p < 0.01) or ATRT (atypical teratoid/rhabdoid tumor) (9.3% vs. 3.9%, p < 0.01). Patients with postoperative dysphagia also had a longer length of stay (33.7 vs. 12.7 days, p < 0.01) and were more likely to be discharged to inpatient rehabilitation (25.6% vs. 9.1%, p < 0.01). Ten patients (5.1%) were PEG-dependent by 1-year follow-up. These patients were younger (2.7 vs. 5.6 years, p < 0.01), had a longer length of stay (55.5 vs. 27.4 days, p < 0.01), and were more likely to have ATRT (30.0% vs. 0.0%, p < 0.01). Recovery was not associated with tumor grade or extent of resection. CONCLUSIONS: Dysphagia after PFT resection is associated with younger age, aggressive tumor histology, and increased healthcare utilization. While most patients recover, a small percentage are still dependent on enteral feeding at 1-year follow-up. Further research is needed to identify factors associated with persistent deficits.

Pediatric posterior fossa incidentalomas.

PURPOSE: Pediatric brain incidentalomas are increasingly being diagnosed. As the posterior fossa (PF) is the location of most brain tumors in children, lesions of this region are of special interest. Currently, the natural history of incidental lesions in the PF is unknown. We present our experience treating such lesions. METHODS: A retrospective study was carried out in two large tertiary pediatric centers. Patients were included if they had an incidental PF lesion suspected of being a tumor, and diagnosed before the age of 20 years. We analyzed treatment strategy, pathology, and outcome of operated and non-operated cases. RESULTS: Seventy children (31 females) with a mean age of 8.4 ± 6.1 years were included. The three most common indications for imaging were headaches (16, assumed to be unrelated to the lesions), workup of unrelated conditions (14), and unspecified reasons (14). Twenty-seven patients (39%) were operated immediately, and 43 followed, of which 12 were eventually operated due to radiological changes, 28.9 ± 16.2 months after diagnosis. The most commonly found pathology was pilocytic astrocytomas (21 of 39 operated cases). Almost 10% were found to be malignant tumors including medulloblastomas (5) and ATRT (1). CONCLUSION: Incidental PF lesions in children include both benign and malignant tumors. While certain lesions may be followed, others may require surgical treatment. Specific treatment decisions are based on initial radiological appearance, change in radiological characteristics over time, location, and evolving symptoms. The surgical risks must be balanced vis-à-vis the risk of missing a high-grade tumor and the very rare risk of malignant transformation.

Cerebellar mutism after posterior fossa tumor resection in children: a multicenter international retrospective study to determine possible modifiable factors.

PURPOSE: A preliminary survey of pediatric neurosurgeons working at different centers around the world suggested differences in clinical practice resulting in variation in the risk of pediatric cerebellar mutism (CM) and cerebellar mutism syndrome (CMS) after posterior fossa (PF) tumor resection. The purposes of this study were (1) to determine the incidence and severity of CM and CMS after midline PF tumor resection in children treated at these centers and (2) to identify potentially modifiable factors related to surgical management (rather than tumor biology) that correlate with the incidence of CM/CMS. METHODS: Attending pediatric neurosurgeons at British Columbia's Children's Hospital (BCCH) and neurosurgeons who completed a pediatric neurosurgery fellowship at BCCH were invited to provide data from the center where they currently practiced. Children aged from birth to less than 18 years who underwent initial midline PF tumor resection within a contemporary, center-selected 2-year period were included. Data was obtained by retrospective chart and imaging review. Modifiable surgical factors that were assessed included pre-resection surgical hydrocephalus treatment, surgical positioning, ultrasonic aspirator use, intraoperative external ventricular drain (EVD) use, surgical access route to the tumor, and extent of resection. CM was defined as decreased or absent speech output postoperatively and CMS as CM plus new or worsened irritability. RESULTS: There were 263 patients from 11 centers in 6 countries (Canada, Germany, the Netherlands, India, Indonesia, and the USA). Median age at surgery was 6 years (range < 1 to 17 years). The overall incidence of postoperative CM was 23.5% (range 14.7-47.6% for centers with data on ≥ 20 patients). The overall incidence of CMS was 6.5% (range 0-10.3% for centers contributing data on ≥ 20 patients). A multivariate logistic regression on the full data set showed no significant association between pre-resection surgical hydrocephalus treatment, prone position, ultrasonic aspirator use, EVD use, telovelar approach, complete or near total resection, or treating center and either postoperative CM or CMS. CONCLUSIONS: While there was variation in surgical management of midline PF tumors among centers participating in this study, the factors in management that were examined did not predict postoperative CM or CMS.

Cerebellar mutism: the predictive role of preoperative language evaluation.

BACKGROUND: The association between preoperative language impairment and development of cerebellar mutism after surgical treatment of posterior fossa tumors has gained increasing interest in recent years based on the concept that both local compression/infiltration of the infratentorial periventricular anatomical structures involved in speech and language, as well as an increased distraction of supratentorial periventricular anatomical structures, due to an associated hydrocephalus, involved in the coordination of speech circuits, might lead to the subclinical presence of language disturbances already at diagnosis, predicting the development of a cerebellar mutism syndrome after tumor removal. METHODS: A thorough review of the literature on the subject has been performed, together with a review of our institutional experience reporting the related long-term (10 years) results. RESULTS AND CONCLUSIONS: According to our institutional experience, 20/70 (28.5%) children presented preoperative language impairment and developed cerebellar mutism after surgery. A residual impairment persists in 75% of the cases at a follow-up of 2 years, and in 50% of the cases at 10 years, a finding which actually depicts cerebellar mutism no more as a transient deficit but among long-term sequelae. The appearance of complex dysarthria in the postoperative period is a negative prognostic factor for the long-term persistence of speech disturbances.

Predicting postoperative tracheostomy requirement in children undergoing surgery for posterior fossa tumors.

PURPOSE: Posterior fossa tumor (PFT) resection can be associated with postoperative respiratory failure. We aimed to identify risk factors predicting tracheostomy dependence in children after PFT resection. METHODS: Retrospective chart review of all children undergoing PFT resection from April 2007 to May 2017 at our institution was performed. RESULTS: A total of 197 patients were included; 12 (6.1%) required tracheostomy placement at a mean 69.1 days postoperatively (SD 112.7, range 7-388). Patients requiring tracheostomy were younger (3.4 vs. 6.8 years, p < 0.01), more likely to have postoperative dysphagia (91.7% vs. 17.3%, p < 0.01), and more likely to have an ependymoma (41.7% vs. 15.1%, p < 0.01) or astrocytoma (25.0% vs. 8.1%, p < 0.01). Patients with eventual tracheostomy were less likely extubated immediately postoperatively (45.5% vs. 79.6%, p < 0.01), had longer intubation duration postoperatively (5.7 vs. 0.5 days, p < 0.01), and had higher rates of reintubation within 48 h (63.6% vs. 1.3%, p < 0.01). Patients requiring tracheostomy had longer hospital length of stay (45.8 vs. 15.3 days, p < 0.01) and ICU stay postoperatively (13.5 vs. 2.1 days, p < 0.01). Of those requiring tracheostomy, three (25.0%) were decannulated by 1 year postoperatively. Decannulation rates did not vary by age (p < 0.47), extubation failure (p < 0.24), duration of intubation (p < 0.10), tumor histology (p < 0.23), or tumor grade (p < 0.13). CONCLUSION: Lower cranial neuropathy following PFT resection is common. Identifying risk factors correlated with need for tracheostomy can help identify patients who may benefit from early tracheostomy, reducing prolonged intubation trauma, time on mechanical ventilation, and length of stay.

Management of hydrocephalus after resection of posterior fossa lesions in pediatric and adult patients-predictors for development of hydrocephalus.

The surgical management of hydrocephalus in patients with posterior fossa lesions (PFL) is critical for optimal patient outcome(s). Accordingly, it is prudent to identify patients in need of aggressive surgical intervention (i.e., ventriculoperitoneal [VP] shunting). To analyze prevalence of, and risk factors associated with, the development of post-operative hydrocephalus in both pediatrics and adults. A retrospective institutional analysis and review of patient records in those who had undergone PFL surgery was performed. In so doing, the authors identified patients that went on to develop post-operative hydrocephalus. The study included pediatric and adult patients treated between 2009 and 2017. Fifteen of 40 pediatric (37.5%) and 18 of 262 adult (6.9%) patients developed hydrocephalus after PFL surgery. The most common tumor entity in pediatrics was medulloblastoma (34%), astrocytoma (24.4%), and pilocytic astrocytoma (22%), whereas in adults, metastasis (29.5%), meningioma (22%), and acoustic neuroma (17.8%) were most common. Young age ≤ 2 years, medulloblastoma (OR 13.9), and brain stem compression (OR 5.4) were confirmed as independent predictors for hydrocephalus in pediatrics and pilocytic astrocytoma (OR 15.4) and pre-operative hydrocephalus (OR 3.6) in adults, respectively. All patients received VP shunts for hydrocephalus management and the mean follow-up was 29.5 months in pediatrics vs 19.2 months in adults. Overall complication rates related to VP shunts were 33.3% in pediatrics and 16.7% in adults, respectively. Shunt dependency and associated complications in pediatrics were noted to be higher than in adults. Given the identification of predictors for hydrocephalus, it is authors' contention that certain patients with those predictors may ultimately benefit from an alternative treatment regimen (e.g., pre-operative interventions) prior to PFT surgery.

A Rare Case of Intra-Fourth-Ventricular Germinoma, Derived from the Medulla Oblongata.

INTRODUCTION: Extragonadal germinomas rarely emerge from the brain stem; however, proper diagnosis and treatment can result in favorable prognosis. Unfortunately, the preoperative diagnosis of medulla oblongata germinoma is difficult due to insufficient clinical signs and symptoms that are specific to this diagnosis. Case Representation: We present a 12-year-old male patient with an intra-fourth-ventricular germinoma, derived from the medulla oblongata, with no abnormalities in the supratentorial region. The germinoma was initially assessed by advance MRI sequences, including diffusion-weighted imaging, T1 perfusion, and spectroscopy. CONCLUSION: In summary, although existing imaging technologies cannot completely distinguish germinomas from other primary brain neoplasms in the fourth ventricle, in patients aged between 12 and 40 years, a small mass on the dorsal side of medulla oblongata that emerges into the fourth ventricle and is characterized by homogeneous contrast enhancement, the absence of calcification and hemorrhage, and the lack of hydrocephalus should be considered for a potential medulla oblongata germinoma diagnosis.

Endoscopic third ventriculostomy prior to resection of posterior fossa tumors in children.

OBJECTIVE: Hydrocephalus is a common presenting symptom of pediatric posterior fossa tumors and often requires permanent cerebrospinal fluid diversion even after resection. Endoscopic third ventriculostomy (ETV) is a well-established treatment of obstructive hydrocephalus in children. The objective of this study is to demonstrate that ETV prior to posterior fossa tumor resection decreases the rate of postoperative ventriculoperitonal shunt (VPS) placement. METHODS: We performed a retrospective analysis of patients who presented with hydrocephalus and underwent posterior fossa tumor resection between 2005 and 2016 excluding pineal and tectal tumors. The rate of postoperative VPS placement was compared in patients who underwent resection and had a VPS placed perioperatively (historical controls) with patients who underwent ETV prior to resection. The two groups were matched for demographics, tumor histology, and tumor location. We also performed a literature review of prior studies that examined the role of ETV in pediatric posterior fossa tumors. RESULTS: Thirty-six patients in the control group were compared to 38 patients in our study. The patients were matched across all variables (age, gender, tumor histology, and tumor locations). The rate of postoperative VPS placement was 31% in the control group compared to 16% in the ETV group. No complications were encountered during ETV. CONCLUSIONS: Endoscopic third ventriculostomy prior to posterior fossa tumor resection in children appears to decrease the rate of postoperative VPS placement. Given its efficacy and safety, ETV should be considered prior to tumor resection in these patients.