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Hirokazu Takami, Nikki Khoshnood and Mark Bernstein

OBJECTIVE

Awake surgery is becoming more standard and widely practiced for neurosurgical cases, including but not limited to brain tumors. The optimal selection of patients who can tolerate awake surgery remains a challenge. The authors performed an updated cohort study, with particular attention to preoperative clinical and imaging characteristics that may have an impact on the viability of awake craniotomy in individual patients.

METHODS

The authors conducted a single-institution cohort study of 609 awake craniotomies performed in 562 patients. All craniotomies were performed by the same surgeon at Toronto Western Hospital during the period from 2006 to 2018. Analyses of preoperative clinical and imaging characteristics that may have an impact on the viability of awake craniotomy in individual patients were performed.

RESULTS

Twenty-one patients were recorded as having experienced intraoperative adverse events necessitating deeper sedation, which made the surgery no longer “awake.” In 2 of these patients, conversion to general anesthesia was performed. The adverse events included emotional intolerance of awake surgery (n = 13), air embolism (n = 3), generalized seizure (n = 4), and unexpected subarachnoid hemorrhage (n = 1). Preoperative cognitive decline, dysphasia, and low performance status, as indicated by the Karnofsky Performance Status (KPS) score, were significantly associated with emotional intolerance on univariate analysis. Only a preoperative KPS score < 70 was significantly associated with this event on multivariate analysis (p = 0.0057). Compared with patients who did not experience intraoperative adverse events, patients who did were more likely to undergo inpatient admission (p = 0.0004 for all cases; p = 0.0036 for cases originally planned as day surgery), longer hospital stay (p < 0.0001), and discharge to a location other than home (p = 0.032).

CONCLUSIONS

Preoperative physical status was found to be the most decisive factor in predicting whether patients can tolerate an awake craniotomy without complications, whereas older age and history of psychiatric treatment were not necessarily associated with adverse events. Patients who had intraoperative adverse events often had reduced chances of same-day discharge and discharge to home. Preoperative careful selection of patients who are most likely to tolerate the procedure is the key to success for awake surgery.

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Hirokazu Takami, Christopher S. Graffeo, Avital Perry, Caterina Giannini and David J. Daniels

OBJECTIVE

Intracranial germ cell tumors (iGCTs) often arise at the neurohypophysis, their second most common origination, following the pineal region. Neurohypophyseal iGCTs present with stereotypical symptoms, including pituitary dysfunction and visual field deficit, due to their suprasellar location. The goal of this study was to present a large, longitudinal single-institution experience with neurohypophyseal iGCTs to better understand their natural history and identify opportunities for further improvement in treatment outcomes.

METHODS

This is a retrospective, single-institution cohort study of neurohypophyseal iGCTs treated between 1988 and 2017, with a focus on the epidemiology, presentation, natural history, and treatment.

RESULTS

Thirty-five neurosurgically managed patients met inclusion criteria; the median age was 18 years (3 months to 49 years), and 74% of patients were male (n = 26). Thirty-one tumors were germinomas, and 4 were nongerminomatous iGCTs. Presenting symptoms included pituitary insufficiency in 76% (n = 25), visual deficit in 45% (n = 15), and diabetes insipidus (DI) in 61% (n = 20) of patients. Index symptoms included isolated DI in 10 (36%), isolated hormone deficiency in 14 (50%), and concomitant DI and hormone deficiency symptoms in 4 (14%). Radiographic diagnostic latency was common, occurring at a median of 363 days (range 9–2626 days) after onset of the first symptoms and was significantly associated with both DI and hormone deficiency as the index symptoms (no DI vs DI: 360 vs 1083 days, p = 0.009; no hormone deficiency vs hormone deficiency: 245 vs 953 days, p = 0.004). Biochemical abnormalities were heterogeneous; each pituitary axis was dysfunctional in at least 1 patient, with most patients demonstrating at least 2 abnormalities, and pretreatment dysfunction demonstrating a nonsignificant trend toward association with long-term posttreatment hormone supplementation. Among germinomas, whole-brain or whole-ventricle radiotherapy demonstrated significantly improved progression-free and overall survival compared with local therapy (p = 0.009 and p = 0.004, respectively).

CONCLUSIONS

Neurohypophyseal iGCTs are insidious tumors that may pose a diagnostic dilemma, as evidenced by the prolonged latency before radiographic confirmation. Serial imaging and close endocrine follow-up are recommended in patients with a characteristic clinical syndrome and negative imaging, due to the propensity for radiographic latency. Pretreatment biochemical abnormalities may indicate higher risk of posttreatment pituitary insufficiency, and all patients should receive careful endocrine follow-up. Local radiotherapy is prone to treatment failure, while whole-ventricle treatment is associated with improved survival in germinomas.

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Mohammed J. Asha, Hirokazu Takami, Carlos Velasquez, Selfy Oswari, Joao Paulo Almeida, Gelareh Zadeh and Fred Gentili

OBJECTIVE

Transsphenoidal surgery is advocated as the first-line management of growth hormone (GH)–secreting adenomas. Although disease control is defined by strict criteria for biochemical remission, the length of follow-up needed is not well defined in literature. In this report, the authors present their long-term remission rate and identify various predictive factors that might influence the clinical outcome.

METHODS

The authors conducted a single-institute retrospective analysis of all transsphenoidal procedures for GH-secreting adenomas performed from January 2000 to June 2016. The primary outcome was defined as biochemical remission according to the 2010 consensus criteria and measured at the 1-year postoperative mark as well as on the last recorded follow-up appointment.

Secondary variables included recurrence rate, patterns of clinical presentation, and outcome of adjuvant therapy (including repeat surgery). Subgroup analysis was performed for patients who had biochemical or radiological “discordance”—patients who achieved biochemical remission but with incongruent insulin-like growth factor 1 (IGF-1)/GH or residual tumor on MRI. Recurrence-free survival analysis was conducted for patients who achieved remission at 1 year after surgery.

RESULTS

Eighty-one patients (45 female and 36 male) with confirmed acromegaly treated with transsphenoidal surgery were included. In 62 cases the patients were treated with a pure endoscopic approach and in 19 cases an endoscopically assisted microscopic approach was used.

Primary biochemical remission after surgery was achieved in 59 cases (73%) at 1 year after surgery. However, only 41 patients (51%) remained in primary surgical remission (without any adjuvant treatment) at their last follow-up appointment, indicating a recurrence rate of 31% (18 of 59 patients) over the duration of follow-up (mean 100 ± 61 months). Long-term remission rates for pure endoscopic and endoscopically assisted cases were not significantly different (48% vs 52%, p = 0.6). Similarly, no significant difference in long-term remission was detected between primary surgery and repeat surgery (54% vs 33%, p = 0.22).

Long-term remission was significantly influenced by extent of resection, cavernous sinus invasion (radiologically as well as surgically reported), and preoperative and early postoperative GH and IGF-1 levels (within 24–48 hours after surgery) as well as by clinical grade, with lower remission rates in patients with dysmorphic features and/or medical comorbidities (grade 2–3) compared to minimally symptomatic or silent cases (grade 1).

CONCLUSIONS

The long-term surgical remission rate appears to be significantly less than “early” remission rates and is highly dependent on the extent of tumor resection. The authors advocate a long-term follow-up regimen and propose a clinical grading system that may aid in predicting long-term outcome in addition to the previously reported anatomical factors. The role of repeat surgery is highlighted.

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Hirokazu Takami, Christoph M. Prummer, Christopher S. Graffeo, Maria Peris-Celda, Caterina Giannini, Colin L. Driscoll and Michael J. Link

Glioblastoma (GBM) of the internal auditory canal (IAC) is exceedingly rare, with only 3 prior cases reported in the literature. The authors present the fourth case of cerebellopontine angle (CPA) and IAC GBM, and the first in which the lesion mimicked a vestibular schwannoma (VS) early in its natural history. A 55-year-old man presented with tinnitus, hearing loss, and imbalance. MRI identified a left IAC/CPA lesion measuring 8 mm, most consistent with a benign VS. Over the subsequent 4 months he developed facial weakness. The tumor grew remarkably to 24 mm and surgery was recommended; the main preoperative diagnosis was malignant peripheral nerve sheath tumor (MPNST). Resection proceeded via a translabyrinthine approach with resection of cranial nerves VII and VIII, followed by facial-hypoglossal nerve anastomosis. Intraoperative frozen section suggested malignant spindle cell neoplasm, but final histopathological and molecular testing confirmed the lesion to be a GBM. The authors report the first case in which absence of any brainstem interface effectively excluded a primary parenchymal tumor, in particular GBM, from the differential diagnosis. Given the dramatic differences in treatment and prognoses between malignant glioma and MPNST, this case emphasizes the importance of surgical intervention on an aggressively growing lesion, which provides both the best probability of local control and the critical tissue diagnosis.

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Hirokazu Takami, Masahiro Shin, Masafumi Kuroiwa, Ayako Isoo, Kan Takahashi and Nobuhito Saito

Cystic malformations in the posterior cranial fossa result from developmental failure in the paleocerebellum and meninges. The authors present the case of an infant with hydrocephalus associated with cystic dilation of the foramina of Magendie and Luschka.

This 7-month-old female infant presented with sudden onset of tonic-clonic seizures. Computed tomography revealed tetraventricular hydrocephalus. Magnetic resonance imaging demonstrated a cyst communicating with the fourth ventricle and projecting to the cisterna magna and the cerebellopontine cisterns through the foramina of Magendie and Luschka. A suboccipital craniotomy was performed for removal of the cyst wall, and the transparent membrane covering the foramen of Magendie was removed under a microscope. After the surgery, the patient's hydrocephalus improved and a phase contrast cine MR imaging study showed evidence of normal CSF flow at the level of the third and fourth ventricles. Three weeks later, however, the hydrocephalus recurred. An endoscopic third ventriculocisternostomy was performed to address the possibility of stagnant CSF flow in the posterior cranial fossa, but the hydrocephalus continued. Finally the patient underwent placement of a ventriculoperitoneal shunt, resulting in improvement of her symptoms and resolution of the hydrocephalus.

On the basis of this experience and previously published reports, the authors speculate that the cystic malformation in their patient could be classified in a continuum of persistent Blake pouch cysts. Hydrocephalus was caused by a combination of obstruction of CSF flow at the outlets of the fourth ventricle and disequilibrium between CSF production and absorption capacity.

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Hirokazu Takami, Avital Perry, Christopher S. Graffeo, Caterina Giannini, Yoshitaka Narita, Yoichi Nakazato, Nobuhito Saito, Ryo Nishikawa, Masao Matsutani, Koichi Ichimura and David J. Daniels

OBJECTIVE

Central nervous system (CNS) germ cell tumors (GCTs) are rare malignant neoplasms that arise predominantly in adolescents and young adults. CNS GCTs demonstrate characteristic trends in national associations, with implications for both tumor incidence and genetics. Although the incidence of CNS GCTs is markedly higher in East Asia than Western countries, direct comparative analyses between these CNS GCT populations are limited.

METHODS

In Japan, to facilitate the genomic analyses of CNS GCTs, the Intracranial Germ Cell Tumor Genome Analysis Consortium was established in 2011, and more than 200 cases of GCTs are available for both tumor tissue and clinical data, which is organized by the National Cancer Center (NCC) Japan. At the Mayo Clinic, there have been 98 cases of intracranial GCTs treated by the Department of Neurologic Surgery since 1988. In this paper, the authors compared the epidemiology, clinical presentation including location and histology, and prognosis between cases treated in the US and Japan.

RESULTS

There was no significant difference in age and sex distributions between the databases. However, there was a significant difference in the tumor locations; specifically, the frequency of basal ganglia was higher in the NCC database compared with the Mayo Clinic (8.4% vs 0%, p = 0.008), and bifocal location (neurohypophysis and pineal gland) was higher at the Mayo Clinic than at the NCC (18.8% vs 5.8%, p = 0.002). There was no difference in histological subdivisions between the databases. There was no difference in progression-free survival (PFS) and overall survival (OS) of germinoma cases and OS of nongerminomatous GCT (NGGCT) cases treated with chemotherapy and radiation therapy covering whole ventricles. However, PFS of NGGCTs differed significantly, and was better in the NCC cohorts (p = 0.04).

CONCLUSIONS

There appears to be a differential distribution of GCTs by neuroanatomical location between major geographic and national groups. Further study is warranted to better characterize any underlying genomic, epigenetic, or environmental factors that may be driving the phenotypic differences.