Browse

You are looking at 81 - 90 of 105 items for

  • Refine by Access: all x
  • By Author: Kano, Hideyuki x
Clear All
Restricted access

Hideyuki Kano, L. Dade Lunsford, John C. Flickinger, Huai-che Yang, Thomas J. Flannery, Nasir R. Awan, Ajay Niranjan, Josef Novotny Jr., and Douglas Kondziolka

Object

The aim of this paper was to define the outcomes and risks of stereotactic radiosurgery (SRS) for Spetzler-Martin Grade I and II arteriovenous malformations (AVMs).

Methods

Between 1987 and 2006, the authors performed Gamma Knife surgery in 996 patients with brain AVMs, including 217 patients with AVMs classified as Spetzler-Martin Grade I or II. The median maximum diameter and target volumes were 1.9 cm (range 0.5–3.8 cm) and 2.3 cm3 (range 0.1–14.1 cm3), respectively. The median margin dose was 22 Gy (range 15–27 Gy).

Results

Arteriovenous malformation obliteration was confirmed by MR imaging in 148 patients and by angiography in 100 patients with a median follow-up of 64 months (range 6–247 months). The actuarial rates of total obliteration determined by angiography or MR imaging after 1 SRS procedure were 58%, 87%, 90%, and 93% at 3, 4, 5, and 10 years, respectively. The median time to complete MR imaging–determined obliteration was 30 months. Factors associated with higher AVM obliteration rates were smaller AVM target volume, smaller maximum diameter, and greater marginal dose. Thirteen patients (6%) suffered hemorrhages during the latency period, and 6 patients died. Cumulative rates of AVM hemorrhage 1, 2, 3, 5, and 10 years after SRS were 3.7%, 4.2%, 4.2%, 5.0%, and 6.1%, respectively. This corresponded to rates of annual bleeding risk of 3.7%, 0.3%, and 0.2% for Years 0–1, 1–5, and 5–10, respectively, after SRS. The presence of a coexisting aneurysm proximal to the AVM correlated with a significantly higher hemorrhage risk. Temporary symptomatic adverse radiation effects developed in 5 patients (2.3%) after SRS, and 2 patients (1%) developed delayed cysts.

Conclusions

Stereotactic radiosurgery is a gradually effective and relatively safe option for patients with smaller volume Spetzler-Martin Grade I or II AVMs who decline initial resection. Hemorrhage after obliteration did not occur in this series. Patients remain at risk for a bleeding event during the latency interval until obliteration occurs. Patients with aneurysms and an AVM warrant more aggressive surgical or endovascular treatment to reduce the risk of a hemorrhage in the latency period after SRS.

Restricted access

Hideyuki Kano, Douglas Kondziolka, John C. Flickinger, Huai-che Yang, Thomas J. Flannery, Nasir R. Awan, Ajay Niranjan, Josef Novotny Jr., and L. Dade Lunsford

Object

The authors conducted a study to define the long-term outcomes and risks of stereotactic radiosurgery (SRS) for pediatric arteriovenous malformations (AVMs).

Methods

Between 1987 and 2006, the authors performed Gamma Knife surgery in 996 patients with brain AVMs; 135 patients were younger than 18 years of age. The median maximum diameter and target volumes were 2.0 cm (range 0.6–5.2 cm) and 2.5 cm3 (range 0.1–17.5 cm3), respectively. The median margin dose was 20 Gy (range 15–25 Gy).

Results

The actuarial rates of total obliteration documented by angiography or MR imaging at 71.3 months (range 6–264 months) were 45%, 64%, 67%, and 72% at 3, 4, 5, and 10 years, respectively. The median time to complete angiographically documented obliteration was 48.9 months. Of 81 patients with 4 or more years of follow-up, 57 patients (70%) had total obliteration documented by angiography. Factors associated with a higher rate of documented AVM obliteration were smaller AVM target volume, smaller maximum diameter, and larger margin dose. In 8 patients (6%) a hemorrhage occurred during the latency interval, and 1 patient died. The rates of AVM hemorrhage after SRS were 0%, 1.6%, 2.4%, 5.5%, and 10.0% at 1, 2, 3, 5, and 10 years, respectively. The overall annual hemorrhage rate was 1.8%. Larger volume AVMs were associated with a significantly higher risk of hemorrhage after SRS. Permanent neurological deficits due to adverse radiation effects developed in 2 patients (1.5%) after SRS, and in 1 patient (0.7%) delayed cyst formation occurred.

Conclusions

Stereotactic radiosurgery is a gradually effective and relatively safe management option for pediatric patients in whom surgery is considered to pose excessive risks. Although hemorrhage after AVM obliteration did not occur in the present series, patients remain at risk during the latency interval until obliteration is complete. The best candidates for SRS are pediatric patients with smaller volume AVMs located in critical brain regions.

Restricted access

Hideyuki Kano, Douglas Kondziolka, John C. Flickinger, Huai-che Yang, Thomas J. Flannery, Nasir R. Awan, Ajay Niranjan, Josef Novotny Jr., and L. Dade Lunsford

Object

The object of this study was to evaluate the outcomes and risks of repeat stereotactic radiosurgery (SRS) for incompletely obliterated cerebral arteriovenous malformations (AVMs).

Methods

Between 1987 and 2006, Gamma Knife surgery was performed in 996 patients with AVMs. During this period, repeat SRS was performed in 105 patients who had incompletely obliterated AVMs at a median of 40.9 months after initial SRS (range 27.5–139 months). The median AVM target volume was 6.4 cm3 (range 0.2–26.3 cm3) at initial SRS but was reduced to 2.3 cm3 (range 0.1–18.2 cm3) at the time of the second procedure. The median margin dose at both initial SRS and repeat SRS was 18 Gy.

Results

The actuarial rate of total obliteration by angiography or MR imaging after repeat SRS was 35%, 68%, 77%, and 80% at 3, 4, 5, and 10 years, respectively. The median time to complete angiographic or MR imaging obliteration after repeat SRS was 39 months. Factors associated with a higher rate of AVM obliteration were smaller residual AVM target volume (p = 0.038) and a volume reduction of 50% or more after the initial procedure (p = 0.014). Seven patients (7%) had a hemorrhage in the interval between initial SRS and repeat SRS. Seventeen patients (16%) had hemorrhage after repeat SRS and 6 patients died. The cumulative actuarial rates of new AVM hemorrhage after repeat SRS were 1.9%, 8.1%, 10.1%, 10.1%, and 22.4% at 1, 2, 3, 5, and 10 years, respectively, which translate to annual hemorrhage rates of 4.05% and 1.79% of patients developing new post–repeat-SRS hemorrhages per year for Years 0–2 and 2–10 following repeat SRS. Factors associated with a higher risk of hemorrhage after repeat SRS were a greater number of prior hemorrhages (p = 0.008), larger AVM target volume at initial SRS (p = 0.010), larger target volume at repeat SRS (p = 0.002), initial AVM volume reduction less than 50% (p = 0.019), and a higher Pollock-Flickinger score (p = 0.010). Symptomatic adverse radiation effects developed in 5 patients (4.8%) after initial SRS and in 10 patients (9.5%) after repeat SRS. Prior embolization (p = 0.022) and a higher Spetzler-Martin grade (p = 0.004) were significantly associated with higher rates of adverse radiation effects after repeat SRS. Delayed cyst formation occurred in 5 patients (4.8%) at a median of 108 months after repeat SRS (range 47–184 months).

Conclusions

Repeat SRS for incompletely obliterated AVMs increases the eventual obliteration rate. Hemorrhage after obliteration did not occur in this series. The best results for patients with incompletely obliterated AVMs were seen in patients with a smaller residual nidus volume and no prior hemorrhages.

Restricted access

Hideyuki Kano, Douglas Kondziolka, John C. Flickinger, Huai-che Yang, Thomas J. Flannery, Ajay Niranjan, Josef Novotny Jr., and L. Dade Lunsford

Object

The authors conducted a study to define the long-term outcomes and risks of stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMs) of the basal ganglia and thalamus.

Methods

Between 1987 and 2006, the authors performed Gamma Knife surgery in 996 patients with brain AVMs; 56 patients had AVMs of the basal ganglia and 77 had AVMs of the thalamus. In this series, 113 (85%) of 133 patients had a prior hemorrhage. The median target volume was 2.7 cm3 (range 0.1–20.7 cm3) and the median margin dose was 20 Gy (range 15–25 Gy).

Results

Obliteration of the AVM eventually was documented on MR imaging in 78 patients and on angiography in 63 patients in a median follow-up period of 61 months (range 2–265 months). The actuarial rates documenting total obliteration after radiosurgery were 57%, 70%, 72%, and 72% at 3, 4, 5, and 10 years, respectively. Factors associated with a higher rate of AVM obliteration included AVMs located in the basal ganglia, a smaller target volume, a smaller maximum diameter, and a higher margin dose. Fifteen (11%) of 133 patients suffered a hemorrhage during the latency period and 7 patients died. The rate of post-SRS AVM hemorrhage was 4.5%, 6.2%, 9.0%, 11.2%, and 15.4% at 1, 2, 3, 5, and 10 years, respectively. The overall annual hemorrhage rate was 4.7%. When 5 patients with 7 hemorrhages occurring earlier than 6 months after SRS were removed from this analysis, the annual hemorrhage rate decreased to 2.7%. Larger volume AVMs had a higher risk of hemorrhage after SRS. Permanent neurological deficits due to adverse radiation effects (AREs) developed in 6 patients (4.5%), and in 1 patient a delayed cyst developed 56 months after SRS. No patient died of AREs. Factors associated with a higher risk of symptomatic AREs were larger target volume, larger maximum diameter, lower margin dose, and a higher Pollock-Flickinger score.

Conclusions

Stereotactic radiosurgery is a gradually effective and relatively safe management option for deep-seated AVMs in the basal ganglia and thalamus. Although hemorrhage after obliteration did not occur in the present series, patients remain at risk during the latency interval between SRS and obliteration. The best candidates for SRS are patients with smaller volume AVMs located in the basal ganglia.

Restricted access

Hideyuki Kano, Douglas Kondziolka, John C. Flickinger, Huai-che Yang, Thomas J. Flannery, Ajay Niranjan, Josef Novotny Jr., and L. Dade Lunsford

Object

In this paper, the authors' goal was to define the long-term outcomes and risks of stereotactic radiosurgery (SRS) for arteriovenous malformations (AVMs) of the medulla, pons, and midbrain.

Methods

Between 1987 and 2006, the authors performed Gamma Knife surgery in 996 patients with brain AVMs; 67 patients had AVMs in the brainstem. In this series, 51 patients (76%) had a prior hemorrhage. The median target volume was 1.4 cm3 (range 0.1–13.4 cm3). The median margin dose was 20 Gy (range 14–25.6 Gy).

Results

Obliteration of the AVMs was eventually documented in 35 patients at a median follow-up of 73 months (range 6–269 months). The actuarial rates of documentation of total obliteration were 41%, 70%, 70%, and 76% at 3, 4, 5, and 10 years, respectively. Higher rates of AVM obliteration were associated only with a higher margin dose. Four patients (6%) suffered a hemorrhage during the latency period, and 2 patients died. The rate of AVM hemorrhage after SRS was 3.0%, 3.0%, and 5.8% at 1, 5, and 10 years, respectively. The overall annual hemorrhage rate was 1.9%. Permanent neurological deficits due to adverse radiation effects (AREs) developed in 7 patients (10%) after SRS, and a delayed cyst developed in 2 patients (3%). One patient died at an outside institution with symptoms of AREs and unrecognized hydrocephalus. Higher 12-Gy volumes and higher Spetzler-Martin grades were associated with a higher risk of symptomatic AREs. Ten of 22 patients who had ocular dysfunction before SRS had improvement, 9 were unchanged, and 3 were worse due to AREs. Eight of 14 patients who had hemiparesis before SRS improved, 5 were unchanged, and 1 was worse.

Conclusions

Although hemorrhage after obliteration did not occur in this series, patients remained at risk during the latency interval until obliteration occurred. Thirty-eight percent of the patients who had neurological deficits due to prior hemorrhage improved. Higher dose delivery in association with conformal and highly selective SRS is required for safe and effective radiosurgery.

Restricted access

Hideyuki Kano, Douglas Kondziolka, John C. Flickinger, Kyung-Jae Park, Phillip V. Parry, Huai-che Yang, Sait Sirin, Ajay Niranjan, Josef Novotny Jr., and L. Dade Lunsford

Object

The object of this study was to define the long-term outcomes and risks of arteriovenous malformation (AVM) management using 2 or more stages of stereotactic radiosurgery (SRS) for symptomatic large-volume lesions unsuitable for surgery.

Methods

In 1992, the authors prospectively began to stage the treatment of anatomical components to deliver higher single doses to AVMs with a volume of more than 10 cm3. Forty-seven patients with such AVMs underwent volume-staged SRS. In this series, 18 patients (38%) had a prior hemorrhage and 21 patients (45%) underwent prior embolization. The median interval between the first-stage SRS and the second-stage SRS was 4.9 months (range 2.8–13.8 months). The median target volume was 11.5 cm3 (range 4.0–26 cm3) in the first-stage SRS and 9.5 cm3 in the second-stage SRS. The median margin dose was 16 Gy (range 13–18 Gy) for both stages.

Results

In 17 patients, AVM obliteration was confirmed after 2–4 SRS procedures at a median follow-up of 87 months (range 0.4–209 months). Five patients had near-total obliteration (volume reduction > 75% but residual AVM). The actuarial rates of total obliteration after 2-stage SRS were 7%, 20%, 28%, and 36% at 3, 4, 5, and 10 years, respectively. The 5-year total obliteration rate after the initial staged volumetric SRS with a margin dose of 17 Gy or more was 62% (p = 0.001). Sixteen patients underwent additional SRS at a median interval of 61 months (range 33–113 months) after the initial 2-stage SRS. The overall rates of total obliteration after staged and repeat SRS were 18%, 45%, and 56% at 5, 7, and 10 years, respectively. Ten patients sustained hemorrhage after staged SRS, and 5 of these patients died. Three of 16 patients who underwent repeat SRS sustained hemorrhage after the procedure and died. Based on Kaplan-Meier analysis (excluding the second hemorrhage in the patient who had 2 hemorrhages), the cumulative rates of AVM hemorrhage after SRS were 4.3%, 8.6%, 13.5%, and 36.0% at 1, 2, 5, and 10 years, respectively. This corresponded to annual hemorrhage risks of 4.3%, 2.3%, and 5.6% for Years 0–1, 1–5, and 5–10 after SRS. Multiple hemorrhages before SRS correlated with a significantly higher risk of hemorrhage after SRS. Symptomatic adverse radiation effects were detected in 13% of patients, but no patient died as a result of an adverse radiation effect. Delayed cyst formation did not occur in any patient after SRS.

Conclusions

Prospective volume-staged SRS for large AVMs unsuitable for surgery has potential benefit but often requires more than 2 procedures to complete the obliteration process. To have a reasonable chance of benefit, the minimum margin dose should be 17 Gy or greater, depending on the AVM location. In the future, prospective volume-staged SRS followed by embolization (to reduce flow, obliterate fistulas, and occlude associated aneurysms) may improve obliteration results and further reduce the risk of hemorrhage after SRS.

Restricted access

Hideyuki Kano, Douglas Kondziolka, David Mathieu, Scott L. Stafford, Thomas J. Flannery, Ajay Niranjan, Bruce E. Pollock, Anthony M. Kaufmann, John C. Flickinger, and L. Dade Lunsford

Object

The aim of this study was to evaluate the outcomes of Gamma Knife surgery (GKS) when used for patients with intractable cluster headache (CH).

Methods

Four participating centers of the North American Gamma Knife Consortium identified 17 patients who underwent GKS for intractable CH between 1996 and 2008. The median patient age was 47 years (range 26–83 years). The median duration of pain before GKS was 10 years (range 1.3–40 years). Seven patients underwent unsuccessful prior surgical procedures, including microvascular decompression (2 patients), microvascular decompression with glycerol rhizotomy (2 patients), deep brain stimulation (1 patient), trigeminal ganglion stimulation (1 patient), and prior GKS (1 patient). Fourteen patients had associated autonomic symptoms. The radiosurgical target was the trigeminal nerve (TN) root and the sphenopalatine ganglion (SPG) in 8 patients, only the TN in 8 patients, and only the SPG in 1 patient. The median maximum TN and SPG dose was 80 Gy.

Results

Favorable pain relief (Barrow Neurological Institute Grades I–IIIb) was achieved and maintained in 10 (59%) of 17 patients at a median follow-up of 34 months. Three patients required additional procedures (repeat GKS in 2 patients, hypothalamic deep brain stimulation in 1 patient). Eight (50%) of 16 patients who had their TN irradiated developed facial sensory dysfunction after GKS.

Conclusions

Gamma Knife surgery for intractable, medically refractory CH provided lasting pain reduction in approximately 60% of patients, but was associated with a significantly greater chance of facial sensory disturbances than GKS used for trigeminal neuralgia.

Restricted access

Huai-che Yang, Hideyuki Kano, Nasir Raza Awan, L. Dade Lunsford, Ajay Niranjan, John C. Flickinger, Josef Novotny Jr., Jagdish P. Bhatnagar, and Douglas Kondziolka

Object

Stereotactic radiosurgery (SRS) is an important management option for patients with small- and medium-sized vestibular schwannomas. To assess the potential role of SRS in larger tumors, the authors reviewed their recent experience.

Methods

Between 1994 and 2008, 65 patients with vestibular schwannomas between 3 and 4 cm in one extracanalicular maximum diameter (median tumor volume 9 ml) underwent Gamma Knife surgery. Seventeen patients (26%) had previously undergone resection.

Results

The median follow-up duration was 36 months (range 1–146 months). At the first planned imaging follow-up at 6 months, 5 tumors (8%) were slightly expanded, 53 (82%) were stable in size, and 7 (11%) were smaller. Two patients (3%) underwent resection within 6 months due to progressive symptoms. Two years later, with 63 tumors overall after the 2 post-SRS resections, 16 tumors (25%) had a volume reduction of more than 50%, 22 (35%) tumors had a volume reduction of 10–50%, 18 (29%) were stable in volume (volume change < 10%), and 7 (11%) had larger volumes (5 of the 7 patients underwent resection and 1 of the 7 underwent repeat SRS). Eighteen (82%) of 22 patients with serviceable hearing before SRS still had serviceable hearing after SRS more than 2 years later. Three patients (5%) developed symptomatic hydrocephalus and underwent placement of a ventriculoperitoneal shunt. In 4 patients (6%) trigeminal sensory dysfunction developed, and in 1 patient (2%) mild facial weakness (House-Brackmann Grade II) developed after SRS. In univariate analysis, patients who had a previous resection (p = 0.010), those with a tumor volume exceeding 10 ml (p = 0.05), and those with Koos Grade 4 tumors (p = 0.02) had less likelihood of tumor control after SRS.

Conclusions

Although microsurgical resection remains the primary management choice in patients with low comorbidities, most vestibular schwannomas with a maximum diameter less than 4 cm and without significant mass effect can be managed satisfactorily with Gamma Knife radiosurgery.

Restricted access

Kyung-Jae Park, Hideyuki Kano, Douglas Kondziolka, Ajay Niranjan, John C. Flickinger, and L. Dade Lunsford

Object

The authors report their experience of using Gamma Knife surgery (GKS) in patients with subependymal giant cell astrocytoma (SEGA).

Methods

Over a 20-year period, the authors identified 6 patients with SEGAs who were eligible for GKS. The median patient age was 16.5 years (range 7–55 years). In 4 patients, GKS was used as a primary management therapy. One patient underwent radiosurgery for recurrent tumors after prior resection, and in 1 patient GKS was used as an adjunct after subtotal resection. The median tumor volume at GKS was 2.75 cm3 (range 0.7–5.9 cm3). A median radiation dose of 14 Gy (range 11–20 Gy) was delivered to the tumor margin.

Results

The median follow-up duration was 73 months (range 42–90 months). Overall local tumor control was achieved in 4 tumors (67%) with progression-free periods of 24, 42, 57, and 66 months. Three tumors regressed and one remained unchanged. In 2 patients the tumors progressed, and in 1 of these patients the lesion was managed by repeated GKS with subsequent tumor regression. The other relatively large tumor (5.9 cm3) was excised 9 months after GKS. The progression-free period for all GKS-managed tumors varied from 9 to 66 months. There were no cases of hydrocephalus or GKS-related morbidity.

Conclusions

Gamma Knife surgery may be an additional minimally invasive management option for SEGA in a patient who harbors a small but progressively enlarging tumor when complete resection is not safely achievable. It may also benefit patients with a residual or recurrent tumor that has progressed after surgery.

Restricted access

Donald N. Liew, Hideyuki Kano, Douglas Kondziolka, David Mathieu, Ajay Niranjan, John C. Flickinger, John M. Kirkwood, Ahmad Tarhini, Stergios Moschos, and L. Dade Lunsford

Object

To evaluate the role of stereotactic radiosurgery (SRS) in the management of brain metastases from melanoma, the authors assessed clinical outcomes and prognostic factors for survival and tumor control.

Methods

The authors reviewed 333 consecutive patients with melanoma who underwent SRS for 1570 brain metastases from cutaneous and mucosal/acral melanoma. The patient population consisted of 109 female and 224 male patients with a median age of 53 years. Two hundred eleven patients (63%) had multiple metastases. One hundred eighteen patients (35%) underwent whole-brain radiation therapy (WBRT). The target volume ranged from 0.1 cm3 to 37.2 cm3. The median marginal dose was 18 Gy.

Results

Actuarial survival rates were 70% at 3 months, 47% at 6 months, 25% at 12 months, and 10% at 24 months after radiosurgery. Factors associated with longer survival included controlled extracranial disease, better Karnofsky Performance Scale score, fewer brain metastases, no prior WBRT, no prior chemotherapy, administration of immunotherapy, and no intratumoral hemorrhage before radiosurgery. The median survival for patients with a solitary brain metastasis, controlled extracranial disease, and administration of immunotherapy after radiosurgery was 22 months. Sustained local tumor control was achieved in 73% of the patients. Sixty-four (25%) of 259 patients who had follow-up imaging after SRS had evidence of delayed intratumoral hemorrhage. Sixteen patients underwent a craniotomy due to intratumoral hemorrhage. Seventeen patients (6%) had asymptomatic and 21 patients (7%) had symptomatic radiation effects. Patients with ≤ 8 brain metastases, no prior WBRT, and the recursive partitioning analysis Class I had extended survivals (median 54.3 months).

Conclusions

Stereotactic radiosurgery is an especially valuable option for patients with controlled systemic disease even if they have multiple metastatic brain tumors.