Browse

You are looking at 1 - 10 of 46 items for

  • By Author: Kano, Hideyuki x
  • By Author: Niranjan, Ajay x
Clear All
Restricted access

Ajay Niranjan, Ahmed Kashkoush, Hideyuki Kano, Edward A. Monaco III, John C. Flickinger and L. Dade Lunsford

OBJECTIVE

Seizures are the second-most common presenting symptom in patients with lobar arteriovenous malformations (AVMs). However, few studies have assessed the long-term effect of stereotactic radiosurgery (SRS) on seizure control. The authors of this study assess the outcome of SRS for these patients to identify prognostic factors associated with seizure control.

METHODS

Patients with AVM who presented with a history of seizure and underwent SRS at the authors’ institution between 1987 and 2012 were retrospectively assessed. The total cohort included 155 patients with a mean follow-up of 86 months (range 6–295 months). Primary outcomes assessed were seizure frequency, antiepileptic drug regimen, and seizure freedom for 6 months prior to last follow-up.

RESULTS

Seizure-free status was achieved in 108 patients (70%), with an additional 23 patients (15%) reporting improved seizure frequency as compared to their pre-SRS status. The median time to seizure-free status was estimated to be 12 months (95% CI 0–27 months) as evaluated via Kaplan-Meier survival analysis. The mean seizure frequency prior to SRS was 14.2 (95% CI 5.4–23.1) episodes per year. Although not all patients tried, the proportion of patients successfully weaned off all antiepileptic drugs was 18% (28/155 patients). On multivariate logistic regression, focal impaired awareness seizure type (also known as complex partial seizures) and superficial venous drainage were significantly associated with a decreased odds ratio for seizure-free status at last follow-up (OR 0.37 [95% CI 0.15–0.92] for focal impaired awareness seizures; OR 0.36 [95% CI 0.16–0.81] for superficial venous drainage). The effects of superficial venous drainage on seizure outcome were nonsignificant when excluding patients with < 2 years of follow-up. AVM obliteration did not correlate with long-term seizure freedom (p = 0.202, chi-square test).

CONCLUSIONS

This study suggests that SRS improves long-term seizure control and increases the likelihood of being medication free, independently of AVM obliteration. Patients with focal impaired awareness seizures were less likely to obtain long-term seizure relief.

Restricted access

Kyung-Jae Park, Hideyuki Kano, Aditya Iyer, Xiaomin Liu, Daniel A. Tonetti, Craig Lehocky, Andrew Faramand, Ajay Niranjan, John C. Flickinger, Douglas Kondziolka and L. Dade Lunsford

OBJECTIVE

The authors of this study evaluate the long-term outcomes of stereotactic radiosurgery (SRS) for cavernous sinus meningioma (CSM).

METHODS

The authors retrospectively assessed treatment outcomes 5–18 years after SRS in 200 patients with CSM. The median patient age was 57 years (range 22–83 years). In total, 120 (60%) patients underwent Gamma Knife SRS as primary management, 46 (23%) for residual tumors, and 34 (17%) for recurrent tumors after one or more surgical procedures. The median tumor target volume was 7.5 cm3 (range 0.1–37.3 cm3), and the median margin dose was 13.0 Gy (range 10–20 Gy).

RESULTS

Tumor volume regressed in 121 (61%) patients, was unchanged in 49 (25%), and increased over time in 30 (15%) during a median imaging follow-up of 101 months. Actuarial tumor control rates at the 5-, 10-, and 15-year follow-ups were 92%, 84%, and 75%, respectively. Of the 120 patients who had undergone SRS as a primary treatment (primary SRS), tumor progression was observed in 14 (11.7%) patients at a median of 48.9 months (range 4.8–120.0 months) after SRS, and actuarial tumor control rates were 98%, 93%, 85%, and 85% at the 1-, 5-, 10-, and 15-year follow-ups post-SRS. A history of tumor progression after microsurgery was an independent predictor of an unfavorable response to radiosurgery (p = 0.009, HR = 4.161, 95% CI 1.438–12.045). Forty-four (26%) of 170 patients who had presented with at least one cranial nerve (CN) deficit improved after SRS. Development of new CN deficits after initial microsurgical resection was an unfavorable factor for improvement after SRS (p = 0.014, HR = 0.169, 95% CI 0.041–0.702). Fifteen (7.5%) patients experienced permanent CN deficits without evidence of tumor progression at a median onset of 9 months (range 2.3–85 months) after SRS. Patients with larger tumor volumes (≥ 10 cm3) were more likely to develop permanent CN complications (p = 0.046, HR = 3.629, 95% CI 1.026–12.838). Three patients (1.5%) developed delayed pituitary dysfunction after SRS.

CONCLUSIONS

This long-term study showed that Gamma Knife radiosurgery provided long-term tumor control for most patients with CSM. Patients who underwent SRS for progressive tumors after prior microsurgery had a greater chance of tumor growth than the patients without prior surgery or those with residual tumor treated after microsurgery.

Restricted access

Hideyuki Kano, John C. Flickinger, Aya Nakamura, Rachel C. Jacobs, Daniel A. Tonetti, Craig Lehocky, Kyung-Jae Park, Huai-che Yang, Ajay Niranjan and L. Dade Lunsford

OBJECTIVE

The management of large-volume arteriovenous malformations (AVMs) with stereotactic radiosurgery (SRS) remains challenging. The authors retrospectively tested the hypothesis that AVM obliteration rates can be improved by increasing the percentage volume of an AVM that receives a minimal threshold dose of radiation.

METHODS

In 1992, the authors prospectively began to stage anatomical components in order to deliver higher single doses to AVMs > 15 cm3 in volume. Since that time 60 patients with large AVMs have undergone volume-staged SRS (VS-SRS). The median interval between the first stage and the second stage was 4.5 months (2.8–13.8 months). The median target volume was 11.6 cm3 (range 4.3–26 cm3) in the first-stage SRS and 10.6 cm3 (range 2.8–33.7 cm3) in the second-stage SRS. The median margin dose was 16 Gy (range 13–18 Gy) for both SRS stages.

RESULTS

AVM obliteration after the initial two staged volumetric SRS treatments was confirmed by MRI alone in 4 patients and by angiography in 11 patients at a median follow-up of 82 months (range 0.4–206 months) after VS-SRS. The post–VS-SRS obliteration rates on angiography were 4% at 3 years, 13% at 4 years, 23% at 5 years, and 27% at 10 years. In multivariate analysis, only ≥ 20-Gy volume coverage was significantly associated with higher total obliteration rates confirmed by angiography. When the margin dose is ≥ 17 Gy and the 20-Gy SRS volume included ≥ 63% of the total target volume, the angiographically confirmed obliteration rates increased to 61% at 5 years and 70% at 10 years.

CONCLUSIONS

The outcomes of prospective VS-SRS for large AVMs can be improved by prescribing an AVM margin dose of ≥ 17 Gy and adding additional isocenters so that ≥ 63% of the internal AVM dose receives more than 20 Gy.

Restricted access

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

OBJECTIVE

Aggressive dural arteriovenous fistulas (dAVFs) with cortical venous drainage (CVD) are known for their relatively high risk of recurrent neurological events or hemorrhage. However, recent natural history literature has indicated that nonaggressive dAVFs with CVD have a significantly lower prospective risk of hemorrhage. These nonaggressive dAVFs are typically diagnosed because of symptomatic headache, pulsatile tinnitus, or ocular symptoms, as in low-risk dAVFs. Therefore, the viability of stereotactic radiosurgery (SRS) as a treatment for this lesion subclass should be investigated.

METHODS

The authors evaluated their institutional experience with SRS for dAVFs with CVD for the period from 1991 to 2016, assessing angiographic outcomes and posttreatment hemorrhage rates. They subsequently pooled their results with those published in the literature and stratified the results based on the mode of clinical presentation.

RESULTS

In an institutional cohort of 42 dAVFs with CVD treated using SRS, there were no complications or hemorrhages after treatment in 19 patients with nonaggressive dAVFs, but there was 1 radiation-induced complication and 1 hemorrhage among the 23 patients with aggressive dAVFs. In pooling these cases with 155 additional cases from the literature, the authors found that the hemorrhage rate after SRS was significantly lower among the patients with nonaggressive dAVFs (0% vs 6.8%, p = 0.003). Similarly, the number of radiation-related complications was 0/124 in nonaggressive dAVF cases versus 6/73 in aggressive dAVF cases (p = 0.001). The annual rate of hemorrhage after SRS for aggressive fistulas was 3.0% over 164.5 patient-years, whereas none of the nonaggressive fistulas bled after radiosurgery over 279.4 patient-years of follow-up despite the presence of CVD.

CONCLUSIONS

Cortical venous drainage is thought to be a significant risk factor in all dAVFs. In the institutional experience described here, SRS proved to be a low-risk strategy associated with a very low risk of subsequent hemorrhage or radiation-related complications in nonaggressive dAVFs with CVD.

Restricted access

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.

Free access

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.

Free access

Seyed H. Mousavi, Ajay Niranjan, Berkcan Akpinar, Edward A. Monaco III, Jonathan Cohen, Jagdish Bhatnagar, Yue-Fang Chang, Hideyuki Kano, Sakibul Huq, John C. Flickinger and L. Dade Lunsford

OBJECTIVE

During the last 25 years, more than 100,000 patients worldwide with trigeminal neuralgia (TN) have undergone stereotactic radiosurgery (SRS) with a standard dose of radiation. However, the radiobiological effect of radiation is determined by the amount of energy delivered to the tissue (integral dose [ID] = mean dose × target volume) and is directly associated with the nerve volume. Although the trigeminal nerve volume varies among patients with TN, the clinical impact of this variation in delivered energy is unknown. The objective of this study was to evaluate the effect of delivered ID on the outcome of TN radiosurgery.

METHODS

The authors evaluated 155 patients with unilateral TN who had undergone SRS as their initial surgical management over a 13-year period. The authors measured the postganglionic ID within the SRS target and retrospectively stratified patients into 3 groups: low (< 1.4 mJ), medium (1.4–2.7 mJ), and high (> 2.7 mJ) ID. Clinical outcomes, which included pain status (scored using the Barrow Neurological Institute Pain Scale) and sensory dysfunction (scored using the Barrow Neurological Institute Numbness Scale), were evaluated at a median follow-up of 71 months.

RESULTS

Patients who were treated with a medium ID had superior pain relief either with or without medications (p = 0.006). In the medium ID group, the rates of complete pain relief without medications at 1, 3, and 6 years after SRS were 67%, 54%, and 33%, respectively, while the rates in the rest of the cohort were 55%, 36%, and 19%, respectively. Patients given a high ID had a higher rate of post-SRS trigeminal sensory deterioration (p < 0.0001). At 1, 3, and 6 years after SRS, the high ID group had an estimated rate for developing sensory dysfunction of 35%, 45%, and 50%, respectively, while the rates in patients receiving low and medium IDs were 3%, 4%, and 9%, respectively. The optimal clinical outcome (maximum pain relief and minimal trigeminal sensory dysfunction) was obtained in patients who had received a medium ID.

CONCLUSIONS

With current dose selection methods, nerve volume affects long-term clinical outcomes in patients with TN who have undergone SRS. This study suggests that the prescribed SRS dose should be customized for each TN patient based on the nerve volume.

Full access

Seyed H. Mousavi, Ajay Niranjan, Berkcan Akpinar, Marshall Huang, Hideyuki Kano, Daniel Tonetti, John C. Flickinger and L. Dade Lunsford

OBJECTIVE

In the era of MRI, vestibular schwannomas are often recognized when patients still have excellent hearing. Besides success in tumor control rate, hearing preservation is a main goal in any procedure for management of this population. The authors evaluated whether modified auditory subclassification prior to radiosurgery could predict long-term hearing outcome in this population.

METHODS

The authors reviewed a quality assessment registry that included the records of 1134 vestibular schwannoma patients who had undergone stereotactic radiosurgery during a 15-year period (1997–2011). The authors identified 166 patients who had Gardner-Robertson Class I hearing prior to stereotactic radiosurgery. Fifty-three patients were classified as having Class I-A (no subjective hearing loss) and 113 patients as Class I-B (subjective hearing loss). Class I-B patients were further stratified into Class I-B1 (pure tone average ≤ 10 dB in comparison with the contralateral ear; 56 patients), and I-B2 (> 10 dB compared with the normal ear; 57 patients). At a median follow-up of 65 months, the authors evaluated patients' hearing outcomes and tumor control.

RESULTS

The median pure tone average elevations after stereotactic radiosurgery were 5 dB, 13.5 dB, and 28 dB in Classes I-A, I-B1, and I-B2, respectively. The median declines in speech discrimination scores after stereotactic radiosurgery were 0% for Class I-A (p = 0.33), 8% for Class I-B1 (p < 0.0001), and 40% for Class I-B2 (p < 0.0001). Serviceable hearing preservation rates were 98%, 73%, and 33% for Classes I-A, I-B1, and I-B2, respectively. Gardner-Robertson Class I hearing was preserved in 87%, 43%, and 5% of patients in Classes I-A, I-B1, and I-B2, respectively.

CONCLUSIONS

Long-term hearing preservation was significantly better if radiosurgery was performed prior to subjective hearing loss. In patients with subjective hearing loss, the difference in pure tone average between the affected ear and the unaffected ear was an important factor in long-term hearing preservation.