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Hideyuki Kano, Antonio Meola, Huai-che Yang, Wan-Yuo Guo, Roberto Martínez-Alvarez, Nuria Martínez-Moreno, Dusan Urgosik, Roman Liscak, Or Cohen-Inbar, Jason Sheehan, John Y. K. Lee, Mahmoud Abbassy, Gene H. Barnett, David Mathieu, Douglas Kondziolka, and L. Dade Lunsford

OBJECTIVE

For some jugular foramen schwannomas (JFSs), complete resection is possible but may be associated with significant morbidity. Stereotactic radiosurgery (SRS) is a minimally invasive alternative or adjunct to microsurgery for JFSs. The authors reviewed clinical and imaging outcomes of SRS for patients with these tumors.

METHODS

Nine participating centers of the International Gamma Knife Research Foundation identified 92 patients who underwent SRS between 1990 and 2013. Forty-one patients had prior subtotal microsurgical resection. The median interval between previous surgery and SRS was 15 months (range 0.5–144 months). Eighty-four patients had preexisting cranial nerve (CN) symptoms and signs. The median tumor volume was 4.1 cm3 (range 0.8–22.6 cm3), and the median margin dose was 12.5 Gy (range 10–18 Gy). Patients with neurofibromatosis were excluded from this study.

RESULTS

The median follow-up was 51 months (range 6–266 months). Tumors regressed in 47 patients, remained stable in 33, and progressed in 12. The progression-free survival (PFS) was 93% at 3 years, 87% at 5 years, and 82% at 10 years. In the entire series, only a dumbbell shape (extension extracranially via the jugular foramen) was significantly associated with worse PFS. In the group of patients without prior microsurgery (n = 51), factors associated with better PFS included tumor volume < 6 cm3 (p = 0.037) and non–dumbbell-shaped tumors (p = 0.015). Preexisting cranial neuropathies improved in 27 patients, remained stable in 51, and worsened in 14. The CN function improved after SRS in 12% of patients at 1 year, 24% at 2 years, 27% at 3 years, and 32% at 5 years. Symptomatic adverse radiation effects occurred in 7 patients at a median of 7 months after SRS (range 5–38 months). Six patients underwent repeat SRS at a median of 64 months (range 44–134 months). Four patients underwent resection at a median of 14 months after SRS (range 8–30 months).

CONCLUSIONS

Stereotactic radiosurgery proved to be a safe and effective primary or adjuvant management approach for JFSs. Long-term tumor control rates and stability or improvement in CN function were confirmed.

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I. Jonathan Pomeraniec, Hideyuki Kano, Zhiyuan Xu, Brandon Nguyen, Zaid A. Siddiqui, Danilo Silva, Mayur Sharma, Hesham Radwan, Jonathan A. Cohen, Robert F. Dallapiazza, Christian Iorio-Morin, Amparo Wolf, John A. Jane Jr., Inga S. Grills, David Mathieu, Douglas Kondziolka, Cheng-Chia Lee, Chih-Chun Wu, Christopher P. Cifarelli, Tomas Chytka, Gene H. Barnett, L. Dade Lunsford, and Jason P. Sheehan

OBJECTIVE

Gamma Knife radiosurgery (GKRS) is frequently used to treat residual or recurrent nonfunctioning pituitary macroadenomas. There is no consensus as to whether GKRS should be used early after surgery or if radiosurgery should be withheld until there is evidence of imaging-defined progression of tumor. Given the high incidence of adenoma progression after subtotal resection over time, the present study intended to evaluate the effect of timing of radiosurgery on outcome.

METHODS

This is a multicenter retrospective review of patients with nonfunctioning pituitary macroadenomas who underwent transsphenoidal surgery followed by GKRS from 1987 to 2015 at 9 institutions affiliated with the International Gamma Knife Research Foundation. Patients were matched by adenoma and radiosurgical parameters and stratified based on the interval between last resection and radiosurgery. Operative results, imaging data, and clinical outcomes were compared across groups following early (≤ 6 months after resection) or late (> 6 months after resection) radiosurgery.

RESULTS

After matching, 222 patients met the authors’ study criteria (from an initial collection of 496 patients) and were grouped based on early (n = 111) or late (n = 111) GKRS following transsphenoidal surgery. There was a greater risk of tumor progression after GKRS (p = 0.013) and residual tumor (p = 0.038) in the late radiosurgical group over a median imaging follow-up period of 68.5 months. No significant difference in the occurrence of post-GKRS endocrinopathy was observed (p = 0.68). Thirty percent of patients without endocrinopathy in the early cohort developed new endocrinopathies during the follow-up period versus 27% in the late cohort (p = 0.84). Fourteen percent of the patients in the early group and 25% of the patients in the late group experienced the resolution of endocrine dysfunction after original presentation (p = 0.32).

CONCLUSIONS

In this study, early GKRS was associated with a lower risk of radiological progression of subtotally resected nonfunctioning pituitary macroadenomas compared with expectant management followed by late radiosurgery. Delaying radiosurgery may increase patient risk for long-term adenoma progression. The timing of radiosurgery does not appear to significantly affect the rate of delayed endocrinopathy.

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Mohana Rao Patibandla, Dale Ding, Hideyuki Kano, Zhiyuan Xu, John Y. K. Lee, David Mathieu, Jamie Whitesell, John T. Pierce, Paul P. Huang, Douglas Kondziolka, Caleb Feliciano, Rafael Rodriguez-Mercado, Luis Almodovar, Inga S. Grills, Danilo Silva, Mahmoud Abbassy, Symeon Missios, Gene H. Barnett, L. Dade Lunsford, and Jason P. Sheehan

OBJECTIVE

Due to the complexity of Spetzler-Martin (SM) Grade IV–V arteriovenous malformations (AVMs), the management of these lesions remains controversial. The aims of this multicenter, retrospective cohort study were to evaluate the outcomes after single-session stereotactic radiosurgery (SRS) for SM Grade IV–V AVMs and determine predictive factors.

METHODS

The authors retrospectively pooled data from 233 patients (mean age 33 years) with SM Grade IV (94.4%) or V AVMs (5.6%) treated with single-session SRS at 8 participating centers in the International Gamma Knife Research Foundation. Pre-SRS embolization was performed in 71 AVMs (30.5%). The mean nidus volume, SRS margin dose, and follow-up duration were 9.7 cm3, 17.3 Gy, and 84.5 months, respectively. Statistical analyses were performed to identify factors associated with post-SRS outcomes.

RESULTS

At a mean follow-up interval of 84.5 months, favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RIC) and was achieved in 26.2% of patients. The actuarial obliteration rates at 3, 7, 10, and 12 years were 15%, 34%, 37%, and 42%, respectively. The annual post-SRS hemorrhage rate was 3.0%. Symptomatic and permanent RIC occurred in 10.7% and 4% of the patients, respectively. Only larger AVM diameter (p = 0.04) was found to be an independent predictor of unfavorable outcome in the multivariate logistic regression analysis. The rate of favorable outcome was significantly lower for unruptured SM Grade IV–V AVMs compared with ruptured ones (p = 0.042). Prior embolization was a negative independent predictor of AVM obliteration (p = 0.024) and radiologically evident RIC (p = 0.05) in the respective multivariate analyses.

CONCLUSIONS

In this multi-institutional study, single-session SRS had limited efficacy in the management of SM Grade IV–V AVMs. Favorable outcome was only achieved in a minority of unruptured SM Grade IV–V AVMs, which supports less frequent utilization of SRS for the management of these lesions. A volume-staged SRS approach for large AVMs represents an alternative approach for high-grade AVMs, but it requires further investigation.

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Gautam U. Mehta, Georgios Zenonos, Mohana Rao Patibandla, Chung Jung Lin, Amparo Wolf, Inga Grills, David Mathieu, Brendan McShane, John Y. Lee, Kevin Blas, Douglas Kondziolka, Cheng-Chia Lee, L. Dade Lunsford, and Jason P. Sheehan

OBJECTIVE

Meningiomas are the most common benign extramedullary lesions of the foramen magnum; however, their optimal management remains undefined. Given their location, foramen magnum meningiomas (FMMs) can cause significant morbidity, and complete microsurgical removal can be challenging. Anterior and anterolateral FMMs carry greater risks with surgery, but they comprise the majority of these lesions. As an alternative to resection, stereotactic radiosurgery (SRS) has been used to treat FMMs in small case series. To more clearly define the outcomes of SRS and to delineate a rational management paradigm for these lesions, the authors analyzed the safety and efficacy of SRS for FMM in an international multicenter trial.

METHODS

Seven medical centers participating in the International Gamma Knife Research Foundation (IGKRF) provided data for this retrospective cohort study. Patients who were treated with Gamma Knife radiosurgery and whose clinical and radiological follow-up was longer than 6 months were eligible for study inclusion. Data from pre- and post-SRS radiological and clinical evaluations were analyzed. Stereotactic radiosurgery treatment variables were recorded.

RESULTS

Fifty-seven patients (39 females and 18 males, with a median age of 64 years) met the study inclusion criteria. Thirty-two percent had undergone prior microsurgical resection. Patients most frequently presented with cranial neuropathy (39%), headache (35%), numbness (32%), and ataxia (30%). Median pre-SRS tumor volume was 2.9 cm3. Median SRS margin dose was 12.5 Gy (range 10–16 Gy). At the last follow-up after SRS, 49% of tumors were stable, 44% had regressed, and 7% had progressed. Progression-free survival rates at 5 and 10 years were each 92%. A greater margin dose was associated with a significantly increased likelihood of tumor regression, with 53% of tumors treated with > 12 Gy regressing. Fifty-two percent of symptomatic patients noted some clinical improvement. Adverse radiation effects were limited to hearing loss and numbness in 1 patient (2%).

CONCLUSIONS

Stereotactic radiosurgery for FMM frequently results in tumor control or tumor regression, as well as symptom improvement. Margin doses > 12 Gy were associated with increased rates of tumor regression. Stereotactic radiosurgery was generally safe and well tolerated. Given its risk-benefit profile, SRS may be particularly useful in the management of small- to moderate-volume anterior and anterolateral FMMs.

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Daniel A. Tonetti, Bradley A. Gross, Kyle M. Atcheson, Brian T. Jankowitz, Hideyuki Kano, Edward A. Monaco III, Ajay Niranjan, John C. Flickinger, and L. Dade Lunsford

OBJECTIVE

The authors of this study found that, given the latency period required for arteriovenous malformation (AVM) obliteration after stereotactic radiosurgery (SRS), a study with limited follow-up cannot assess the benefit of SRS for unruptured AVMs.

METHODS

The authors reviewed their institutional experience with “ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations)–eligible” AVMs treated with SRS between 1987 and 2016, with the primary outcome defined as stroke (ischemic or hemorrhagic) or death (AVM related or AVM unrelated). Patients with at least 3 years of follow-up in addition to those who experienced stroke or died during the latency period were included. Secondary outcome measures included obliteration rates, patients with new seizure disorders, and those with new focal deficits without stroke.

RESULTS

Of 233 patients included in this study, 32 had a stroke or died after SRS over the mean 8.4-year follow-up (14%). Utilizing the 10% stroke or death rate at a mean 2.8-year follow-up for untreated AVMs in ARUBA, the rate in the authors’ study is significantly lower than that anticipated at the 8.4-year follow-up for an untreated cohort (14% vs 30%, p = 0.0003). Notwithstanding obliteration, in this study, annualized rates of hemorrhage and stroke or death after 3 years following SRS were 0.4% and 0.8%, respectively. The overall obliteration rate was 72%; new seizure disorders, temporary new focal deficits without stroke, and permanent new focal deficits without stroke occurred in 2% of patients each.

CONCLUSIONS

After a sensible follow-up period exceeding the latency period, there is a lower rate of stroke/death for patients with treated, unruptured AVMs with SRS than for patients with untreated AVMs.

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Cheng-Chia Lee, Jason P. Sheehan, Hideyuki Kano, Berkcan Akpinar, Roberto Martinez-Alvarez, Nuria Martinez-Moreno, Wan-Yuo Guo, L. Dade Lunsford, and Kang-Du Liu

OBJECTIVE

Cavernous sinus hemangiomas (CSHs) are rare vascular tumors. A direct microsurgical approach usually results in massive hemorrhage and incomplete tumor resection. Although stereotactic radiosurgery (SRS) has emerged as a therapeutic alternative to microsurgery, outcome studies are few. Authors of the present study evaluated the role of SRS for CSH.

METHODS

An international multicenter study was conducted to review outcome data in 31 patients with CSH. Eleven patients had initial microsurgery before SRS, and the other 20 patients (64.5%) underwent Gamma Knife SRS as the primary management for their CSH. Median age at the time of radiosurgery was 47 years, and 77.4% of patients had cranial nerve dysfunction before SRS. Patients received a median tumor margin dose of 12.6 Gy (range 12–19 Gy) at a median isodose of 55%.

RESULTS

Tumor regression was confirmed by imaging in all 31 patients, and all patients had greater than 50% reduction in tumor volume at 6 months post-SRS. No patient had delayed tumor growth, new cranial neuropathy, visual function deterioration, adverse radiation effects, or hypopituitarism after SRS. Twenty-four patients had presented with cranial nerve disorders before SRS, and 6 (25%) of them had gradual improvement. Four (66.7%) of the 6 patients with orbital symptoms had symptomatic relief at the last follow-up.

CONCLUSIONS

Stereotactic radiosurgery was effective in reducing the volume of CSH and attaining long-term tumor control in all patients at a median of 40 months. The authors' experience suggests that SRS is a reasonable primary and adjuvant treatment modality for patients in whom a CSH is diagnosed.

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Marshall J. Huang, Hideyuki Kano, Seyed H. Mousavi, Ajay Niranjan, Edward A. Monaco III, Yoshio Arai, John C. Flickinger, and L. Dade Lunsford

OBJECTIVE

The goal of this retrospective cohort study was to assess long-term outcomes in patients with vestibular schwannoma (VS) who underwent stereotactic radiosurgery (SRS) after initial microsurgical resection.

METHODS

From the authors' database of 1770 patients with VS, the authors retrospectively analyzed data from 173 Gamma Knife SRS procedures for VS after 1 (128 procedures) or multiple (45 procedures) microsurgical resections. The median length of the interval between the last resection and SRS was 42 months (range 2–329 months). The median length of clinical follow-up was 74 months (range 6–285 months). Progression-free survival after SRS was determined with Kaplan-Meier analysis.

RESULTS

At the time of SRS, the hearing of 161 patients (93%) was Gardner-Robertson Class V, and 81 patients (47%) had facial neuropathy (i.e., facial function with House-Brackmann [HB] grades of III–VI), 87 (50%) had trigeminal neuropathy, and 71 (41%) reported imbalance or disequilibrium disorders. The median tumor volume was 2.7 cm3 (range 0.2–21.6 cm3), and the median dose to the tumor margin was 13 Gy (range 11–20 Gy). Radiosurgery controlled growth of 163 (94%) tumors. Progression-free survival after SRS was 97% at 3 years, 95% at 5 years, and 90% at 10 years. Four patients with delayed tumor progression underwent repeat SRS at a median of 35 months (range 23–64 months) after the first SRS. Four patients (2.3%) with tumor progression underwent repeat resection at a median of 25 months (range 19–33 months). Among the patients with any facial dysfunction (indicated by HB grades of II–VI), 19% had improvement in this condition after SRS, and 5.5% with some facial function (indicated by HB grades of I–V) developed more facial weakness. Among patients with trigeminal neuropathy, 20% had improvement in this condition, and 5.8% developed or had worsened trigeminal neuropathy after SRS.

CONCLUSIONS

Stereotactic radiosurgery offered a safe and effective long-term management strategy for VS patients whose tumors remained or recurred after initial microsurgery.

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Ajay Niranjan, Sudesh S. Raju, Edward A. Monaco III, John C. Flickinger, and L. Dade Lunsford

OBJECTIVE

Unilateral Gamma Knife thalamotomy (GKT) is a well-established treatment for patients with medically refractory tremor who are not eligible for invasive procedures due to increased risk of compications. The purpose of this study was to evaluate whether staged bilateral GKT provides benefit with acceptable risk to patients suffering from disabling medically refractory bilateral tremor.

METHODS

Eleven patients underwent staged bilateral GKT during a 17-year period (1999–2016). Eight patients had essential tremor (ET), 2 had Parkinson's disease (PD)–related tremor, and 1 had multiple-sclerosis (MS)–related tremor. For the first GKT, a median maximum dose of 140 Gy was delivered to the posterior-inferior region of the nucleus ventralis intermedius (VIM) through a single isocenter with 4-mm collimators. Patients who benefitted from unilateral GKT were eligible for a contralateral GKT 1–2 years later (median 22 months). For the second GKT, a median maximum dose of 130 Gy was delivered to the opposite VIM nucleus to a single 4-mm isocenter. The Fahn-Tolosa-Marin (FTM) clinical tremor rating scale was used to score tremor, drawing, and drinking before and after each GKT. The FTM writing score was assessed only for the dominant hand before and after the first GKT. The Karnofsky Performance Status (KPS) was used to assess quality of life and activities of daily living before and after the first and second GKT.

RESULTS

The median time to last follow-up after the first GKT was 35 months (range 11–70 months). All patients had improvement in at least 1 FTM score after the first GKT. Three patients (27.3%) had tremor arrest and complete restoration of function (noted via FTM tremor, writing, drawing, and drinking scores equaling zero). No patient had tremor recurrence or diminished tremor relief after the first GKT. One patient experienced new temporary neurological deficit (contralateral lower-extremity hemiparesis) from the first GKT. The median time to last follow-up after the second GKT was 12 months (range 2–70 months). Nine patients had improvement in at least 1 FTM score after the second GKT. Two patients had tremor arrest and complete restoration of function. No patient experienced tremor recurrence or diminished tremor relief after the second GKT. No patient experienced new neurological or radiological adverse effect from the second GKT. Statistically significant improvements were noted in the KPS score following the first and second GKT.

CONCLUSIONS

Staged bilateral GKT provided effective relief for medically refractory, disabling, bilateral tremor without increased risk of neurological complications. It is an appropriate strategy for carefully selected patients with medically refractory bilateral tremor who are not eligible for deep brain stimulation.

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Nitin Agarwal, Sumana S. Kommana, David R. Hansberry, Ahmed I. Kashkoush, Robert M. Friedlander, and L. Dade Lunsford

OBJECTIVE

Closing the knowledge gap that exists between patients and health care providers is essential and is facilitated by easy access to patient education materials. Although such information has the potential to be an effective resource, it must be written in a user-friendly and understandable manner, especially when such material pertains to specialized and highly technical fields such as neurological surgery. The authors evaluated the accessibility, usability, and reliability of current educational resources provided by the American Association of Neurological Surgeons (AANS), Healthwise, and the National Institute for Neurological Disorders and Stroke (NINDS).

METHODS

Online neurosurgical patient education information provided by AANS, Healthwise, and NINDS was evaluated using the LIDA scale, a website quality assessment tool, by medical professionals and nonmedical professionals. A high achieving score is regarded as 90% or greater using the LIDA scale.

RESULTS

Accessibility scores were 76.7% (AANS), 83.3% (Healthwise), and 75.0% (NINDS). Average usability scores for the AANS, Healthwise, and NINDS were 73.3%, 82.6%, and 82.9%, respectively, when evaluated by medical professionals and 78.5%, 80.7%, and 75.9%, respectively, for nonmedical professionals, respectively. Average reliability scores were 58.5%, 53.3%, 72.6%, respectively, for medical professionals and 70.4%, 66.7%, and 78.5%, respectively, for nonmedical professionals when evaluating the AANS, Healthwise, and NINDS websites.

CONCLUSIONS

Although organizations like AANS, Healthwise, and NINDS should be commended for their ongoing commitment to provide health care–oriented materials, modification of this material is suggested to improve the patient education value.