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Isaac Yang, Won Kim, Antonio De Salles and Marvin Bergsneider

Object

Stereotactic radiosurgery (SRS) has emerged as an adjuvant radiation-based therapy for pituitary adenomas. Here, the authors present a systematic analysis of SRS for growth hormone–secreting adenomas to characterize the efficacy of SRS in the treatment of acromegaly.

Methods

A comprehensive search of the English language literature revealed 970 patients with new, recurrent, or persistent acromegaly that had been treated using SRS along with assessable and quantifiable outcome data. Articles published between June 1998 and September 2009 were included in the analysis. Patient outcome data were aggregated and investigated based on tumor size, radiosurgery dose, and clinical outcomes both with and without medication.

Results

The overall disease control rate without medication was 48%–53%, and the overall disease control rate with or without medication was 73%. The overall mean duration of the reported follow-up was 48.5 ± 25.8 months. The mean overall tumor volume in this analysis was 2.11 ± 1.16 cm3. The Pearson product-moment correlation coefficient for tumor volume and cure rate was not significant (r = 0.0668, p = 0.8546).

Conclusions

Data from this analysis suggest that tumor size may not be a significant prognostic factor in disease control after radiosurgery for acromegaly. The overall disease control rate was approximately 48% without suppressive medications after radiosurgery for acromegaly. With the advancement of increasingly sophisticated stereotactic planning and tumor targeting, the precision of radiosurgery may continue to improve in the treatment of acromegaly.

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Daniel T. Nagasawa, Zachary A. Smith, Nicole Cremer, Christina Fong, Daniel C. Lu and Isaac Yang

Spinal cord ependymomas are rare neoplasms, comprising approximately 5% of all CNS tumors and 15% of all spinal cord tumors. Although surgery was once reserved for diagnosis alone, the evolution of surgical practices has elevated resection to the treatment of choice for these lesions. While technological advances continue to improve the capacity for gross-total resections and thus decrease the risk of recurrence, ependymoma spinal surgery still contains a variety of potential complications. The presence of neurological deficits and deterioration are not uncommonly associated with spinal cord ependymoma surgery, including sensory loss, dorsal column dysfunction, dysesthetic syndrome, and bowel and bladder dysfunction, particularly in the immediate postoperative period. Surgical treatment may also lead to wound complications and CSF leaks, with increased risk when radiotherapy has been involved. Radiation therapy may also predispose patients to radiation myelopathy and ultimately result in neurological damage. Additionally, resections of spinal ependymomas have been associated with postoperative spinal instability and deformities, particularly in the pediatric population. Despite the advances in microsurgical techniques and intraoperative cord monitoring modalities, there remain a number of serious complications related to the treatment of spinal ependymoma tumors. Identification and acknowledgment of these potential problems may assist in their prevention, early detection, and increased quality of life for patients afflicted with this disease.

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Winward Choy, Won Kim, Daniel Nagasawa, Stephanie Stramotas, Andrew Yew, Quinton Gopen, Andrew T. Parsa and Isaac Yang

Meningiomas are mostly benign, slow-growing tumors of the CNS that originate from arachnoidal cap cells. While monosomy 22 is the most frequent genetic abnormality found in meningiomas, a multitude of other aberrant chromosomal alterations, signaling pathways, and growth factors have been implicated in its pathogenesis. Losses on 22q12.2, a region encoding the tumor suppressor gene merlin, represent the most common genetic alterations in early meningioma formation. Malignant meningioma progression, however, is associated with more complex karyotypes and greater genetic instability. Cytogenetic studies of atypical and anaplastic meningiomas revealed gains and losses on chromosomes 9, 10, 14, and 18, with amplifications on chromosome 17. However, the specific gene targets in a majority of these chromosomal abnormalities remain elusive.

Studies have also implicated a myriad of aberrant signaling pathways involved with meningioma tumorigenesis, including those involved with proliferation, angiogenesis, and autocrine loops. Understanding these disrupted pathways will aid in deciphering the relationship between various genetic changes and their downstream effects on meningioma pathogenesis.

Despite advancements in our understanding of meningioma pathogenesis, the conventional treatments, including surgery, radiotherapy, and stereotactic radiosurgery, have remained largely stagnant. Surgery and radiation therapy are curative in the majority of lesions, yet treatment remains challenging for meningiomas that are recurrent, aggressive, or refractory to conventional treatments. Future therapies will include combinations of targeted molecular agents as a result of continued progress in the understanding of genetic and biological changes associated with meningiomas.

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Carlito Lagman, Vera Ong, Lawrance K. Chung, Lekaa Elhajjmoussa, Christina Fong, Anthony C. Wang, Quinton Gopen and Isaac Yang

OBJECTIVE

The purpose of this study is to present an illustrative case of pediatric superior semicircular canal dehiscence (SSCD) and to systematically review the current published literature in the pediatric population.

METHODS

An electronic search of the Scopus, Web of Science, PsycINFO, Cochrane, and Embase databases was performed by 2 independent authors through January 2017. Search term combinations included “pediatrics,” “children,” “canal,” and “dehiscence.” Inclusion criteria were as follows: English, full-text clinical studies, case reports, and case series describing pediatric patient(s) (younger than 18 years) with CT evidence of SSCD. Baseline patient demographic characteristics, clinical presentations, dehiscence characteristics, management strategies, and outcome data were extracted.

RESULTS

A total of 14 studies involving 122 patients were included in the quantitative synthesis. The patients’ mean age was 7.22 years. Male predominance was observed (approximate male-to-female ratio of 1.65:1). Neurodevelopmental disorders were common (n = 14, 11.5%). Auditory signs and symptoms were more common than vestibular signs and symptoms. Hearing loss (n = 62, 50.8%) was the most common auditory symptom and an indicator for imaging evaluation. Vertigo was the most common vestibular symptom (n = 8, 6.6%). Hearing aids were recommended in 8 cases (6.6%), and surgical repair was performed in 1 case (0.8%). Symptom outcomes and follow-up durations were infrequently reported.

CONCLUSIONS

The authors’ data suggest that in pediatric SSCD, males are more commonly affected than females. This is different than the adult population in which females are predominantly affected. A history of otologic and/or neurodevelopmental abnormalities was common. There was a preponderance of auditory symptoms in this age group. Conservative management was favored in the majority.

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Taemin Oh, Daniel T. Nagasawa, Brendan M. Fong, Andy Trang, Quinton Gopen, Andrew T. Parsa and Isaac Yang

Unfavorable outcomes such as facial paralysis and deafness were once unfortunate probable complications following resection of acoustic neuromas. However, the implementation of intraoperative neuromonitoring during acoustic neuroma surgery has demonstrated placing more emphasis on quality of life and preserving neurological function. A modern review demonstrates a great degree of recent success in this regard. In facial nerve monitoring, the use of modern electromyography along with improvements in microneurosurgery has significantly improved preservation. Recent studies have evaluated the use of video monitoring as an adjunctive tool to further improve outcomes for patients undergoing surgery. Vestibulocochlear nerve monitoring has also been extensively studied, with the most popular techniques including brainstem auditory evoked potential monitoring, electrocochleography, and direct compound nerve action potential monitoring. Among them, direct recording remains the most promising and preferred monitoring method for functional acoustic preservation. However, when compared with postoperative facial nerve function, the hearing preservation is only maintained at a lower rate. Here, the authors analyze the major intraoperative neuromonitoring techniques available for acoustic neuroma resection.

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Isaac Yang, Michael E. Sughrue, Martin J. Rutkowski, Rajwant Kaur, Michael E. Ivan, Derick Aranda, Igor J. Barani and Andrew T. Parsa

Object

Craniopharyngiomas have a propensity to recur after resection, potentially causing death through their aggressive local behavior in their critical site of origin. Recent data suggest that subtotal resection (STR) followed by adjuvant radiotherapy (XRT) may be an appealing substitute for gross-total resection (GTR), providing similar rates of tumor control without the morbidity associated with aggressive resection. Here, the authors summarize the published literature regarding rates of tumor control with various treatment modalities for craniopharyngiomas.

Methods

The authors performed a comprehensive search of the English language literature to identify studies publishing outcome data on patients undergoing surgery for craniopharyngioma. Rates of progression-free survival (PFS) and overall survival (OS) were determined through Kaplan-Meier analysis.

Results

There were 442 patients who underwent tumor resection. Among these patients, GTR was achieved in 256 cases (58%), STR in 101 cases (23%), and STR+XRT in 85 cases (19%). The 2- and 5-year PFS rates for the GTR group versus the STR+XRT group were 88 versus 91%, and 67 versus 69%, respectively. The 5- and 10-year OS rates for the GTR group versus the STR+XRT group were 98 versus 99%, and 98 versus 95%, respectively. There was no significant difference in PFS (log-rank test) or OS with GTR (log-rank test).

Conclusions

Given the relative rarity of craniopharyngioma, this study provides estimates of outcome for a variety of treatment combinations, as not all treatments are an option for all patients with these tumors.

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Michael E. Sughrue, Isaac Yang, Seunggu J. Han, Derick Aranda, Ari J. Kane, Misha Amoils, Zachary A. Smith and Andrew T. Parsa

Object

While many studies have been published outlining morbidity following radiosurgical treatment of vestibular schwannomas, significant interpractitioner and institutional variability still exists. For this reason, the authors conducted a systematic review of the literature for non-audiofacial-related morbidity after the treatment of vestibular schwannoma with radiosurgery.

Methods

The authors performed a comprehensive search of the English-language literature to identify studies that published outcome data of patients undergoing radiosurgery treatment for vestibular schwannomas. In total, 254 articles were found that described more than 50,000 patients and were analyzed for satisfying the authors' inclusion criteria. Patients from these studies were then separated into 2 cohorts based on the marginal dose of radiation: ≤ 13 Gy and > 13 Gy. All tumors included in this study were < 25 mm in their largest diameter.

Results

A total of 63 articles met the criteria of the established search protocol, which combined for a total of 5631 patients. Patients receiving > 13 Gy were significantly more likely to develop trigeminal nerve neuropathy than those receiving < 13 Gy (p < 0.001). While we found no relationship between radiation dose and the rate of developing hydrocephalus (0.6% for both cohorts), patients with hydrocephalus who received doses > 13 Gy appeared to have a higher rate of symptomatic hydrocephalus requiring shunt treatment (96% [> 13 Gy] vs 56% [≤ 13 Gy], p < 0.001). The rates of vertigo or balance disturbance (1.1% [> 13 Gy] vs 1.8% [≤ 13 Gy], p = 0.001) and tinnitus (0.1% [> 13 Gy] vs 0.7% [≤ 13 Gy], p = 0.001) were significantly higher in the lower dose cohort than those in the higher dose cohort.

Conclusions

The results of our review of the literature provide a systematic summary of the published rates of nonaudiofacial morbidity following radiosurgery for vestibular schwannoma.

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Thu-Trang Hickman, Matthew E. Shuman, Tatyana A. Johnson, Felix Yang, Rebecca R. Rice, Isaac M. Rice, Esther H. Chung, Robert Wiemann, Megan Tinl, Christine Iracheta, Grace Chen, Patricia Flynn, Mary Beth Mondello, Jillian Thompson, Mary-Ellen Meadows, Rona S. Carroll, Hong Wei Yang, Hongyan Xing, David Pilgrim, E. Antonio Chiocca, Ian F. Dunn, Alexandra J. Golby and Mark D. Johnson

OBJECTIVE

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by ventriculomegaly, gait difficulty, incontinence, and dementia. The symptoms can be ameliorated by CSF drainage. The object of this study was to identify factors associated with shunt-responsive iNPH.

METHODS

The authors reviewed the medical records of 529 patients who underwent shunt placement for iNPH at their institution between July 2001 and March 2015. Variables associated with shunt-responsive iNPH were identified using bivariate and multivariate analyses. Detailed alcohol consumption information was obtained for 328 patients and was used to examine the relationship between alcohol and shunt-responsive iNPH. A computerized patient registry from 2 academic medical centers was queried to determine the prevalence of alcohol abuse among 1665 iNPH patients.

RESULTS

Bivariate analysis identified associations between shunt-responsive iNPH and gait difficulty (OR 4.59, 95% CI 2.32–9.09; p < 0.0001), dementia (OR 1.79, 95% CI 1.14–2.80; p = 0.01), incontinence (OR 1.77, 95% CI 1.13–2.76; p = 0.01), and alcohol use (OR 1.98, 95% CI 1.23–3.16; p = 0.03). Borderline significance was observed for hyperlipidemia (OR 1.56, 95% CI 0.99–2.45; p = 0.054), a family history of hyperlipidemia (OR 3.09, 95% CI 0.93–10.26, p = 0.054), and diabetes (OR 1.83, 95% CI 0.96–3.51; p = 0.064). Multivariate analysis identified associations with gait difficulty (OR 3.98, 95% CI 1.81–8.77; p = 0.0006) and alcohol (OR 1.94, 95% CI 1.10–3.39; p = 0.04). Increased alcohol intake correlated with greater improvement after CSF drainage. Alcohol abuse was 2.5 times more prevalent among iNPH patients than matched controls.

CONCLUSIONS

Alcohol consumption is associated with the development of shunt-responsive iNPH.