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  • Author or Editor: Antonio A. F. De Salles x
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Zachary A. Smith, Antonio A. F. De Salles, Leonardo Frighetto, Bryan Goss, Steve P. Lee, Michael Selch, Robert E. Wallace, Cynthia Cabatan-Awang and Timothy Solberg

Object. In this study the authors evaluate the efficacy of and complications associated with dedicated linear accelerator (LINAC) radiosurgery for trigeminal neuralgia (TN).

Methods. Between August 1995 and February 2001, 60 patients whose median age was 66.1 years (range 45–88 years) were treated with dedicated LINAC radiosurgery for TN. Forty-one patients (68.3%) had essential TN, 12 (20%) had secondary facial pain, and seven (11.7%) had atypical features. Twenty-nine patients (48.3%) had undergone previous surgical procedures. Radiation doses varied between 70 and 90 Gy (mean 83.3 Gy) at the isocenter, with the last 35 patients (58.3%) treated with a 90-Gy dose. A 5-mm collimator was used in 45 patients (75%) and a 7.5-mm collimator in 15 patients (25%). Treatment was focused at the nerve root entry zone.

At last follow up (mean follow-up period 23 months, range 2–70 months), 36 (87.8%) of the 41 patients with essential TN had sustained significant pain relief (good plus excellent results). Twenty-three patients (56.1%) were pain free without medication (excellent outcome), 13 (31.7%) had a 50 to 90% reduction in pain with or without medication (good outcome), and five (12.2%) had minor improvement or no relief. Of 12 patients with secondary facial pain, significant relief was sustained in seven patients (58.3%); worse results were found with atypical pain. Fifteen (25%) of the 60 patients experienced new numbness postprocedure; no other significant complications were found. Pain relief was experienced at a mean of 2.7 months (range 0–12 months).

Conclusions. Dedicated LINAC radiosurgery is a precise and effective treatment for TN.

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Antonio A. F. De Salles, Alessandra G. Pedroso, Paul Medin, Nzhde Agazaryan, Timothy Solberg, Cynthia Cabatan-Awang, Dulce M. Espinosa, Judith Ford and Michael T. Selch

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.

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Rodrigo Couto Torres, Leonardo Frighetto, Antonio A. F. De Salles, Brian Goss, Paul Medin, Timothy Solberg, Judith Marianne Ford and Michael Selch

Object

The authors report the evolution of linear accelerator (LINAC)–based radiosurgery in the treatment of patients with intracranial meningiomas. They describe the technical aspects as well as clinical and radiological outcomes.

Methods

The authors performed a retrospective review of 161 patients harboring 194 intracranial meningiomas treated with various types of stereotactic irradiation at their institution between May 1991 and July 2002. Clinical and radiological follow-up data (mean follow-up period 32.5 months, range 6–125 months) were obtained in 128 patients (79.5%) with 156 meningiomas (80.4%). There were 88 women and 40 men whose mean age was 57.2 years (range 18–87 years). Stereotactic irradiation was the primary treatment in 44 patients, and 84 patients underwent resection prior to radiosurgery. Stereotactic radiosurgery (SRS) was used to treat 79 lesions and fractionated stereotactic radiotherapy (SRT) was used to treat 77. The mean dose for SRS was 1567 cGy (range 1200–2285 cGy) prescribed to a mean isodose line of 66.6% (range 50–90%). Stereotactic radiotherapy was delivered using a mean dose of 4839 cGy (range 2380–5400 cGy), prescribed to a mean isodose line of 89% (range 50–90%).

The mean follow-up periods were 40 and 24 months in SRS- and SRT-treated patients, respectively. Tumor control was achieved in 58 SRT-treated benign meningiomas (90%) and in 70 SRT-treated lesions (97.2%). In patients with atypical meningiomas a considerably poorer prognosis was seen. Clinical improvement or stabilization of symptoms was observed in the majority of patients. Symptomatic complications were limited to four patients (5%) treated with SRS and four (5.2%) treated with SRT.

Conclusions

Stereotactic irradiation techniques have changed the neurosurgical approach to intracranial meningiomas. Either SRS or SRT delivered as a primary treatment in selected cases of skull base lesions or as an adjuvant after conservative resection has improved the management of these complex intracranial tumors.

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Alessandra G. Pedroso, Antonio A. F. De Salles, Katayoun Tajik, Raymond Golish, Zachary Smith, Leonardo Frighetto, Timothy Solberg, Cynthia Cabatan-Awang and Michael T. Selch

Object. The authors studied outcomes and complications in patients who harbored arteriovenous malformations (AVMs) and underwent stereotactic radiosurgery involving the Novalis shaped beam unit.

Methods. Between January 1998 and January 2002, 83 patients were treated with radiosurgery at University of California, Los Angeles. The mean patient age was 37.8 years. Forty-four patients completed follow up. There were 24 women. Sixteen patients underwent repeated radiosurgery. Embolization was performed in 13 patients and radiosurgery alone in 31. The mean follow-up period after embolization was 54.4 ± 21.9 months and 37.4 ± 14.6 months for radiosurgery alone. The mean peripheral dose was 15 Gy (range 12–18 Gy). The mean preradiosurgery lesion volume was 9.7 ± 11.9 ml for radiosurgery alone and 16.2 ± 11.3 ml for embolization. The AVMs in 13 patients (29.8%) were Spetzler—Martin Grade II, 12 (27.5%) were Grade III, eight (18.2%) Grade IV, and five (11.3%) were Grade V and VI each. Spetzler—Martin grade, volume, and peripheral dose were analyzed in consideration to outcome.

A positive trend (p = 0.086) was observed between Spetzler—Martin grade and obliteration rate. Volume per se did not predict obliteration (p = 0.48). A peripheral dose of 18 Gy was shown to be the most important predictor for occlusion (p = 0.007). The overall obliteration rate was 52.5%. A transient complication was noticed in one case (2.3%) and but no permanent deficits due to radiosurgery have been detected so far. Three patients (6.8%) bled after radiosurgery.

Conclusions. The range of the prescribed peripheral dose was narrow. An association between the mean peripheral dose of 15 Gy, high conformality, and homogeneous dose distribution permitted no permanent complications. Volume per se did not correlate with outcome. The next step will be to increase the peripheral dose shaping the beam and to achieve higher obliteration rates without increasing complications.