Preliminary results of linear accelerator radiosurgery for acoustic schwannomas

1996 ◽  
Vol 85 (6) ◽  
pp. 1013-1019 ◽  
Author(s):  
William M. Mendenhall ◽  
William A. Friedman ◽  
John M. Buatti ◽  
Francis J. Bova
Keyword(s):  
Stereotactic Radiosurgery ◽  
Local Control ◽  
Linear Accelerator ◽  
Local Control Rate ◽  
Magnetic Resonance Images ◽  
High Rate ◽  
Content Type ◽  
Treatment Volume ◽  
Fine Print

✓ In this paper the authors evaluate the results of linear accelerator (LINAC)—based stereotactic radiosurgery for acoustic schwannomas. Fifty-six patients underwent LINAC-based stereotactic radiosurgery for acoustic schwannomas at the University of Florida between July 1988 and November 1994. Each patient was followed for a minimum of 1 year or until death; no patient was lost to follow up. One or more follow-up magnetic resonance images or computerized tomography scans were obtained in 52 of the 56 patients. Doses ranged between 10 and 22.5 Gy with 69.6% of patients receiving 12.5 to 15 Gy. Thirty-eight patients (68%) were treated with one isocenter and the dose was specified to the 80% isodose line in 71% of patients. Fifty-five patients (98%) achieved local control after treatment. The 5-year actuarial local control rate was 95%. At the time of analysis, 48 patients were alive and free of disease, seven had died of intercurrent disease, and one was alive with disease. Complications developed in 13 patients (23%). The likelihood of complications was related to the dose and treatment volume: 10 to 12.5 Gy to all volumes, three (13%) of 23 patients; 15 to 17.5 Gy to 5.5 cm3 or less, two (9%) of 23 patients; 15 to 17.5 Gy to more than 5.5 cm3, five (71%) of seven patients; and 20 to 22.5 Gy to all volumes, three (100%) of three patients. Linear accelerator—based stereotactic radiosurgery results in a high rate of local control at 5 years. The risk of complications is related to the dose and treatment volume.

Linear accelerator surgery for meningiomas

2005 ◽  
Vol 103 (2) ◽  
pp. 206-209 ◽  
Author(s):  
William A. Friedman ◽  
Gregory J. Murad ◽  
Patrick Bradshaw ◽  
Robert J. Amdur ◽  
William M. Mendenhall ◽  
...  
Keyword(s):  
Local Control ◽  
Linear Accelerator ◽  
Malignant Tumors ◽  
Local Control Rate ◽  
Benign Tumors ◽  
Content Type ◽  
Single Center Experience ◽  
Study Interval ◽  
Radiation Induced ◽  
Fine Print

Object. In this paper the authors review the results of a single-center experience in the use of linear accelerator (LINAC) surgery for radiosurgical treatment of meningiomas. Methods. A retrospective analysis of all patients treated with LINAC surgery for meningiomas between May 1989 and December 2001 was performed. All patients participated in follow-up review for a minimum of 2 years, and no patients were excluded. Two hundred ten patients were treated during the study interval. The actuarial local control rate for benign tumors was 100% at both 1 and 2 years, and 96% at 5 years. The actuarial local control rate for atypical tumors was 100% at 1 year, 92% at 2 years, and 77% at 5 years; and that for malignant tumors was 100% at both 1 and 2 years, and only 19% at 5 years. Of the 210 patients 13 (6.2%) experienced temporary radiation-induced complications, and only five (2.3%) experienced permanent complications. In all patients with a permanent complication the histological characteristics of the meningioma were malignant. Conclusions. Linear accelerator surgery produced high local control rates and very low rates of permanent morbidity in patients harboring benign meningiomas.

Functional stereotactic radiosurgery involving a dedicated linear accelerator and gamma unit: a comparison study

2004 ◽  
pp. 373-380 ◽  
Author(s):  
Timothy D. Solberg ◽  
Steven J. Goetsch ◽  
Michael T. Selch ◽  
William Melega ◽  
Goran Lacan ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Linear Accelerator ◽  
Treatment Plan ◽  
Single Shot ◽  
Submillimeter Range ◽  
Primate Model ◽  
Content Type ◽  
Stereotactic Frame ◽  
Targeting Ability ◽  
Fine Print

Object. The purpose of this work was to investigate the targeting and dosimetric characteristics of a linear accelerator (LINAC) system dedicated for stereotactic radiosurgery compared with those of a commercial gamma knife (GK) unit. Methods. A phantom was rigidly affixed within a Leksell stereotactic frame and axial computerized tomography scans were obtained using an appropriate stereotactic localization device. Treatment plans were performed, film was inserted into a recessed area, and the phantom was positioned and treated according to each treatment plan. In the case of the LINAC system, four 140° arcs, spanning ± 60° of couch rotation, were used. In the case of the GK unit, all 201 sources were left unplugged. Radiation was delivered using 3- and 8-mm LINAC collimators and 4- and 8-mm collimators of the GK unit. Targeting ability was investigated independently on the dedicated LINAC by using a primate model. Measured 50% spot widths for multisource, single-shot radiation exceeded nominal values in all cases by 38 to 70% for the GK unit and 11 to 33% for the LINAC system. Measured offsets were indicative of submillimeter targeting precision on both devices. In primate studies, the appearance of an magnetic resonance imaging—enhancing lesion coincided with the intended target. Conclusions. Radiosurgery performed using the 3-mm collimator of the dedicated LINAC exhibited characteristics that compared favorably with those of a dedicated GK unit. Overall targeting accuracy in the submillimeter range can be achieved, and dose distributions with sharp falloff can be expected for both devices.

Long-term hearing preservation after surgery for vestibular schwannoma

2005 ◽  
Vol 102 (1) ◽  
pp. 6-9 ◽  
Author(s):  
Simone A. Betchen ◽  
Jane Walsh ◽  
Kalmon D. Post
Keyword(s):  
Hearing Preservation ◽  
Magnetic Resonance Images ◽  
Class I ◽  
Repeated Testing ◽  
Content Type ◽  
Factors Influencing ◽  
Long Term Preservation ◽  
Fine Print

Object. Vestibular schwannomas (VSs) are now amenable to resection with excellent hearing preservation rates. It remains unclear whether immediately postoperative hearing is a durable result and will not diminish over time. The aim of this study was to determine the rate of long-term preservation of functional hearing following surgery for a VS and to examine factors influencing hearing preservation. Methods. All patients eligible for hearing preservation (Gardner—Robertson Class I or II) who had undergone resection of a VS by a single surgeon were reviewed retrospectively. Follow-up audiograms and magnetic resonance images were obtained. Of 142 patients deemed eligible for hearing preservation surgery, 38 had immediate postoperative hearing confirmed by an audiogram. In these patients with preserved hearing, the audiographic results demonstrated functional hearing in 30 (85.7%) of 35 patients who underwent repeated testing at a mean follow-up time of 7 years. Delayed hearing loss occurred in five (14.3%) of the 35 patients and did not correlate significantly with the size of the tumor. Hearing improved one Gardner—Robertson class postoperatively in three (7.9%) of the 38 patients. Conclusions. Long-term functional hearing was maintained in 85.7% of patients when it was preserved immediately postoperatively and the result was independent of tumor size. The results of this study emphasize that long-term preservation of functional hearing is a realistic goal following VS surgery and should be attempted in all patients in whom preoperative hearing is determined to be Gardner—Robertson Class I or II.

Dose—response tolerance of the visual pathways and cranial nerves of the cavernous sinus to stereotactic radiosurgery

1998 ◽  
Vol 88 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Klaus A. Leber ◽  
Jutta Berglöff ◽  
Gerhard Pendl
Keyword(s):  
Stereotactic Radiosurgery ◽  
Cavernous Sinus ◽  
Dose Response ◽  
Cranial Nerves ◽  
Visual Pathways ◽  
Content Type ◽  
Number Of Patients ◽  
Response Tolerance ◽  
Fine Print

As the number of patients treated with stereotactic radiosurgery increases, it becomes particularly important to define with precision adverse effects on distinct structures of the nervous system. Object. This study was designed to assess the dose—response tolerance of the visual pathways and cranial nerves after exposure of the cavernous sinus to radiation. Methods. A total of 66 sites in the visual system and 210 cranial nerves of the middle cranial fossa were investigated in 50 patients who had undergone gamma knife treatment for benign skull base tumors. The mean follow-up period was 40 months (range 24–60 months). Follow-up examinations consisted of neurological, neuroradiological, and neuroophthalmological evaluations. The actuarial incidence of optic neuropathy was zero for patients who received a radiation dose of less than 10 Gy, 26.7% for patients receiving a dose in the range of 10 to less than 15 Gy, and 77.8% for those who received doses of 15 Gy or more (p < 0.0001). Previously impaired vision improved in 25.8% and was unchanged in 51.5% of patients. No sign of neuropathy was seen in patients whose cranial nerves of the cavernous sinus received radiation doses of between 5 and 30 Gy. Because tumor control appeared to have been achieved in 98% of the patients, the deterioration in visual function cannot be attributed to tumor progression. Conclusions. The structures of the visual pathways (the optic nerve, chiasm, and tract) exhibit a much higher sensitivity to single-fraction radiation than other cranial nerves, and their particular dose—response characteristics can be defined. In contrast, the oculomotor and trigeminal nerves have a much higher dose tolerance.

Results of combined stereotactic radiosurgery and transarterial embolization for dural arteriovenous fistulas of the transverse and sigmoid sinuses

2001 ◽  
Vol 94 (6) ◽  
pp. 886-891 ◽  
Author(s):  
Jonathan A. Friedman ◽  
Bruce E. Pollock ◽  
Douglas A. Nichols ◽  
Deborah A. Gorman ◽  
Robert L. Foote ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Transarterial Embolization ◽  
Symptom Relief ◽  
Related Complication ◽  
Content Type ◽  
Arteriovenous Fistulas ◽  
Dural Arteriovenous Fistulas ◽  
Lost To Follow Up ◽  
Fine Print

Object. Most dural arteriovenous fistulas (DAVFs) of the transverse and sigmoid sinuses do not have angiographically demonstrated features associated with intracranial hemorrhage and, therefore, may be treated nonsurgically. The authors report their experience using a staged combination of radiosurgery and transarterial embolization for treating DAVFs involving the transverse and sigmoid sinuses. Methods. Between 1991 and 1998, 25 patients with DAVFs of the transverse and/or sigmoid sinuses were treated using stereotactic radiosurgery; 22 of these patients also underwent transarterial embolization. Two patients were lost to follow-up review. Clinical data, angiographic findings, and follow-up records for the remaining 23 patients were collected prospectively. The mean duration of clinical follow up after radiosurgery was 50 months (range 20–99 months). The 18 women and five men included in this series had a mean age of 57 years (range 33–79 years). Twenty-two (96%) of 23 patients presented with pulsatile tinnitus as the primary symptom; two patients had experienced an earlier intracerebral hemorrhage (ICH). Cognard classifications of the DAVFs included the following: I in 12 patients (52%), IIa in seven patients (30%), and III in four patients (17%). After treatment, symptoms resolved (20 patients) or improved significantly (two patients) in 96% of patients. One patient was clinically unchanged. No patient sustained an ICH or irradiation-related complication during the follow-up period. Seventeen patients underwent follow-up angiographic studies at a mean of 21 months after radiosurgery (range 11–38 months). Total or near-total obliteration (> 90%) was seen in 11 patients (65%), and more than a 50% reduction in six patients (35%). Two patients experienced recurrent tinnitus and underwent repeated radiosurgery and embolization at 21 and 38 months, respectively, after the first procedure. Conclusions. A staged combination of radiosurgery and transarterial embolization provides excellent symptom relief and a good angiographically verified cure rate for patients harboring low-risk DAVFs of the transverse and sigmoid sinuses. This combined approach is a safe and effective treatment strategy for patients without angiographically determined risk factors for hemorrhage and for elderly patients with significant comorbidities.

Radiosurgery for Cushing's disease after failed transsphenoidal surgery

2000 ◽  
Vol 93 (5) ◽  
pp. 738-742 ◽  
Author(s):  
Jonas M. Sheehan ◽  
Mary L. Vance ◽  
Jason P. Sheehan ◽  
Dilantha B. Ellegala ◽  
Edward R. Laws
Keyword(s):  
Gamma Knife ◽  
Cushing’S Disease ◽  
Tumor Size ◽  
Transsphenoidal Surgery ◽  
Gamma Knife Radiosurgery ◽  
Magnetic Resonance Images ◽  
Cushing's Disease ◽  
Content Type ◽  
Fine Print

Object. Although transsphenoidal surgery has become the standard of care for Cushing's disease, it is often unsuccessful in normalizing cortisol production. In this study the authors investigate the safety and efficacy of gamma knife radiosurgery (GKRS) for Cushing's disease after failed transsphenoidal surgery.Methods. The records of all patients who underwent GKRS at the authors' institution after unsuccessful transsphenoidal surgery for Cushing's disease were retrospectively reviewed. Successful treatment was considered a normal or below-normal 24-hour urinary free cortisol (UFC) level. Records were also evaluated for relapse, new-onset endocrine deficiencies, interval change in tumor size, and visual complications.Forty-three patients underwent 44 gamma knife procedures with follow up ranging from 18 to 113 months (mean 39.1, median 44 months). Normal 24-hour UFC levels were achieved in 27 patients (63%) at an average time from treatment of 12.1 months (range 3–48 months). Three patients had a recurrence of Cushing's disease at 19, 37, and 38 months, respectively, after radiosurgery. New endocrine deficiencies were noted in seven patients (16%). Follow-up magnetic resonance images obtained in 33 patients revealed a decrease in tumor size in 24, no change in nine, and an increase in size in none of the patients. One patient developed a quadrantanopsia 14 months after radiosurgery despite having received a dose of only 0.7 Gy to the optic tract.Conclusions. Gamma knife radiosurgery appears to be safe and effective for the treatment of Cushing's disease refractory to pituitary surgery. Delayed recurrences and new hormone deficiencies may occur, indicating the necessity for regular long-term follow up.

Is gross-total resection sufficient treatment for posterior fossa ependymomas?

2005 ◽  
Vol 102 (4) ◽  
pp. 629-636 ◽  
Author(s):  
Leland Rogers ◽  
Jeanette Pueschel ◽  
Robert Spetzler ◽  
William Shapiro ◽  
Stephen Coons ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Posterior Fossa ◽  
Local Control ◽  
Median Duration ◽  
Local Control Rate ◽  
Gross Total Resection ◽  
Total Resection ◽  
Content Type ◽  
Significant Difference ◽  
Fine Print

Object. The goals of this study were to analyze outcomes in patients with posterior fossa ependymomas, determine whether gross-total resection (GTR) alone is appropriate treatment, and evaluate the role of radiation therapy. Methods. All patients with newly diagnosed intracranial ependymomas treated at Barrow Neurological Institute between 1983 and 2002 were identified. Those with supratentorial primary lesions, subependymomas, or neuraxis dissemination were excluded. Forty-five patients met the criteria for the study. Gross-total resection was accomplished in 32 patients (71%) and subtotal resection (STR) in 13 (29%). Radiation therapy was given to 25 patients: 13 following GTR and 12 after STR. The radiation fields were craniospinal followed by a posterior fossa boost in six patients and posterior fossa or local only in the remaining patients. With a median follow-up period of 66 months, the median duration of local control was 73.5 months with GTR alone, but has not yet been reached for patients with both GTR and radiotherapy (p = 0.020). The median duration of local control following STR and radiotherapy was 79.6 months. The 10-year actuarial local control rate was 100% for patients who underwent GTR and radiotherapy, 50% for those who underwent GTR alone, and 36% for those who underwent both STR and radiotherapy, representing significant differences between the GTR-plus-radiotherapy and GTR-alone cohorts (p = 0.018), and between the GTR-plus-radiotherapy and the STR-plus-radiotherapy group (p = 0.003). There was no significant difference in the 10-year actuarial local control rate between the GTR-alone and STR-plus-radiotherapy cohorts (p = 0.370). The 10-year overall survival was numerically superior in patients who underwent both GTR and radiotherapy: 83% compared with 67% in those who underwent GTR alone and 43% in those who underwent both STR and radiotherapy. These differences did not achieve statistical significance. Univariate analyses revealed that radiotherapy, tumor grade, and extent of resection were significant predictors of local control. Conclusions. Gross-total resection should be the intent of surgery when it can be accomplished with an acceptable degree of morbidity. Even after GTR has been confirmed with postoperative imaging, however, adjuvant radiotherapy significantly improves local control. The authors currently recommend the use of postoperative radiotherapy, regardless of whether the resection is gross total or subtotal.

Multiple schwannomas: schwannomatosis or neurofibromatosis type 2?

1998 ◽  
Vol 89 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Matti Tapio Seppälä ◽  
Markku Alarik Sainio ◽  
Matti Jouko Johannes Haltia ◽  
Jaakko Jyri Kinnunen ◽  
Kirsi Hannele Setälä ◽  
...  
Keyword(s):  
Clinical Course ◽  
Positive Family History ◽  
Neurofibromatosis Type ◽  
Magnetic Resonance Images ◽  
Neurofibromatosis Type 2 ◽  
Long Term Outcome ◽  
Content Type ◽  
Fine Print

Object. The aim of this study was to clarify the clinical outcome of schwannomatosis, a rare condition characterized by multiple nonvestibular schwannomas in the absence of meningiomas, intraspinal ependymomas, and other clinical signs of neurofibromatosis type 2 (NF2). Methods. Nine patients with schwannomatosis treated at one institution are presented and their clinical course during a median follow-up time of 9.9 years is discussed. The patients were typically middle-aged at the time of their first operation (median 43.5 years), none had a positive family history of schwannomatosis or NF2, and none showed cutaneous or ocular signs of NF2. On histopathological examination the tumors from the patients with schwannomatosis showed a lobular appearance and frequent Verocay bodies, signs indicating NF2, more often than 20 sporadic schwannomas that were investigated as controls. Two patients died of unrelated causes at 3.2 and 9.9 years, respectively, of follow up. Magnetic resonance images of the head and spine were obtained in seven patients at the end of the follow-up period. New spinal schwannomas were detected in one patient and a residual schwannoma in three. No germline mutations of the NF2 gene were found in these seven patients. Two additional patients originally included in the schwannomatosis group who were 8.6 and 11.7 years old at initial surgery had NF2. One was diagnosed at follow-up review and the other developed a fulminant disease that led to death in 4 years. Conclusions. The clinical course, long-term outcome, and genetic mechanism of schwannomatosis differ from that of NF2.

Spinal lesions treated with Novalis shaped beam intensity-modulated radiosurgery and stereotactic radiotherapy

2004 ◽  
Vol 101 (Supplement3) ◽  
pp. 435-440 ◽  
Author(s):  
Antonio A. F. De Salles ◽  
Alessandra G. Pedroso ◽  
Paul Medin ◽  
Nzhde Agazaryan ◽  
Timothy Solberg ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Stereotactic Radiotherapy ◽  
Systemic Disease ◽  
Content Type ◽  
Shaped Beam ◽  
Intensity Modulated ◽  
Asymptomatic Patients ◽  
The Mean ◽  
Fine Print

Object. Spinal radiosurgery was implemented to improve quality of life (QOL) in patients with malignancies. It may also be applicable to the treatment of benign lesions. Methods. Between July 2002 and January 2004, 14 patients harboring 22 lesions were treated; 13 received single-dose stereotactic radiosurgery. Six were women. The mean age was 60.2 years (range 48–82 years). There were 11 metastases, two neurofibromas, and one meningioma. Six lesions were cervical, 10 thoracic, and six lumbar. Ten patients suffered pain, three paresthesias, two weakness, and three were asymptomatic. Seven patients underwent spinal surgery, with four receiving instrumentation. Twelve patients underwent conventional irradiation before stereotactic radiosurgery/stereotactic radiotherapy. A mean dose of 12 ± 2.7 Gy (range 8–21 Gy) was prescribed to the 91% isodose line (range 85–97%). The mean tumor volume was 25 ± 27.1 ml (range 0.75–91.8 ml). Treatment was planned using intensity-modulated radiosurgery (IMRS) fields in 15 cases, dynamic arcs in five, and conformal beams in two. The mean follow-up period was 6.1 ± 3.9 months (range 1–16 months). Three patients became pain free and four experienced considerable relief. Weakness improved in the two patients with this preoperative symptom and the asymptomatic patients remained so. Four lesions decreased in size, five remained stable, seven progressed, and six were not followed up (two patients died before follow up). Four patients in all died, three of systemic disease and one of thoracic lesion progression. No complications due to shaped beam and IMRS/intensity-modulated radiotherapy (IMRT) techniques were observed. Conclusions. Shaped beam and IMRS/IMRT involving the Novalis system may delay neurological deterioration, improving QOL. The lack of complication suggests that higher doses can be delivered to improve the control rate in patients with metastases.

Resolution of central pain after embolization of an arteriovenous malformation

1999 ◽  
Vol 90 (3) ◽  
pp. 575-579 ◽  
Author(s):  
Toru Fukuhara ◽  
Guy M. McKhann ◽  
Paul Santiago ◽  
Joseph M. Eskridge ◽  
John D. Loeser ◽  
...  
Keyword(s):  
Arteriovenous Malformation ◽  
Stereotactic Radiosurgery ◽  
Complete Resolution ◽  
Pain Syndrome ◽  
Central Pain ◽  
Content Type ◽  
Fine Print

✓ The authors describe a patient with right-sided central pain resulting from a left parietal arteriovenous malformation (AVM). The AVM was treated with staged embolization and stereotactic radiosurgery, and its obliteration was documented on follow-up angiographic studies. Surprisingly, the patient noted complete resolution of her pain syndrome after embolization, which is an extremely rare result. Central pain and its proposed mechanisms are discussed.

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