H. Warren Goldman

Stereotactic radiosurgery and fractionated stereotactic radiotherapy for the treatment of acoustic schwannomas: comparative observations of 125 patients treated at one institution

BACKGROUND Stereotactic radiosurgery (SRS) and, more recently, fractionated stereotactic radiotherapy (SRT) have been recognized as noninvasive alternatives to surgery for the treatment of acoustic schwannomas. We review our experience of acoustic tumor treatments at one institution using a gamma knife for SRS and the first commercial world installation of a dedicated linac for SRT. METHODS Patients were treated with SRS on the gamma knife or SRT on the linac from October 1994 through August 2000. Gamma knife technique involved a fixed-frame multiple shot/high conformality single treatment, whereas linac technique involved daily conventional fraction treatments involving a relocatable frame, fewer isocenters, and high conformality established by noncoplanar arc beam shaping and differential beam weighting. RESULTS Sixty-nine patients were treated on the gamma knife, and 56 patients were treated on the linac, with 1 NF-2 patient common to both units. Three patients were lost to follow-up, and in the remaining 122 patients, mean follow-up was 119 +/- 67 weeks for SRS patients and 115 +/- 96 weeks for SRT patients. Tumor control rates were high (> or =97%) for sporadic tumors in both groups but lower for NF-2 tumors in the SRT group. Cranial nerve morbidities were comparably low in both groups, with the exception of functional hearing preservation, which was 2.5-fold higher in patients who received conventional fraction SRT. CONCLUSION SRS and SRT represent comparable noninvasive treatments for acoustic schwannomas in both sporadic and NF-2 patient groups. At 1-year follow-up, a significantly higher rate of serviceable hearing preservation was achieved in SRT sporadic tumor patients and may therefore be preferable to alternatives including surgery, SRS, or possibly observation in patients with serviceable hearing.

Fractionated stereotactic radiotherapy for the treatment of optic nerve sheath meningiomas: preliminary observations of 33 optic nerves in 30 patients with historical comparison to observation with or without prior surgery.

OBJECTIVE We investigated the safety and efficacy of stereotactic radiotherapy as an alternative therapy to surgical resection for optic nerve sheath meningiomas (ONSMs). METHODS Thirty patients and 33 optic nerves with ONSMs were treated with conventional fractionated stereotactic radiotherapy treatment (CF-SRT) between July 1996 and May 2001 with the use of a 6-MeV LINAC designed for and dedicated to radiosurgery. The LINAC technique involved daily CF-SRT involving a relocatable frame, an average of three isocenters, and high-radiation dose conformality established by noncoplanar arc beam shaping and differential beam weighting. The patients who were treated with CF-SRT were followed clinically with serial visual fields and radiographically with both magnetic resonance imaging and functional 111In-octreotide single-photon emission computed tomography. The results of treatment were compared with a historical control group of ONSM patients who were either observed or treated surgically and then observed. RESULTS Our study population comprised 18 women and 12 men with a median age of 44 years (age range, 20–76 yr). The median isosurface radiation dose was 51 Gy (dose range, 50–54.0 Gy), and the median clinical follow-up time was 89 weeks (range, 9–284 wk). Of 22 optic nerves with vision before CF-SRT, 20 nerves (92%) demonstrated preserved vision, and 42% manifested improvement in visual acuity and/or visual field at follow-up. Comparison of our patients with a historical control group revealed preserved vision in only 16% of patients in a comparable period of observation, along with a 150% greater probability of visual improvement. Four patients (13%) had posttreatment morbidities, including visual loss (two patients), optic neuritis (one patient), and transient orbital pain (one patient). On magnetic resonance imaging studies, there was no evidence of tumor progression or recurrence in all patients, including tumor volume reductions noted in four patients. All six patients monitored with 111In-octreotide scintigraphy demonstrated significant decreases in tumor activity after CF-SRT. CONCLUSION To date, this article describes the largest reported series of ONSMs. Although longer follow-up is necessary, we think that CF-SRT represents a safe alternative to surgery and offers a higher likelihood of preserved or improved vision in patients with ONSM. Our analysis suggests that CF-SRT is also preferable to observation. Functional 111In-octreotide single-photon emission computed tomographic scintigraphy provides a useful technique for the assessment of tumor control that complements serial posttreatment magnetic resonance imaging in patients with ONSMs.

Endoscopic treatment of a symptomatic pineal cyst: technical case report.

Symptomatic pineal cysts are rare and typically managed with an open surgical approach. We report the successful treatment of a symptomatic pineal cyst using a stereotactic endoscopic technique.

Endoscopic Treatment of a Symptomatic Pineal Cyst

Symptomatic pineal cysts are rare and typically managed with an open surgical approach. We report the successful treatment of a symptomatic pineal cyst using a stereotactic endoscopic technique.

Role of enhanced MRI in the follow-up of patients with medically refractory trigeminal neuralgia undergoing stereotactic radiosurgery using the gamma knife: initial experience.

Purpose The purpose of this work was to evaluate the early posttreatment MR findings, and their clinical utility, in patients with trigeminal neuralgia undergoing stereotactic radiosurgery using the gamma knife. Method Twenty-six patients with medically refractory trigeminal neuralgia underwent stereotactic radiosurgery. A single dose of 70–90 Gy was administered to the proximal root entry zone (n = 21) or the retrogasserian portion (n = 5) of the trigeminal nerve. Posttreatment enhanced MRI and clinical assessment were performed at 3–6 months. Results Five patients did not have radiologic follow-up. There were no changes identified in the treated trigeminal nerve or adjacent brainstem in 19 of 21 patients. Two patients with multiple sclerosis developed abnormal signal and enhancement in the brainstem and/or trigeminal nerve; neither had clinical complications. Onset of therapeutic effect ranged from 3 weeks to 3 months; 19 patients had a beneficial response. Conclusion Results of enhanced MRI 3–6 months after stereotactic radiosurgical treatment of trigeminal neuralgia do not correlate with the clinical response. Because beneficial clinical responses or treatment failures are apparent by 3 months, routine posttreatment MRI in these patients is not warranted.

Transorbital craniotomy through a suprabrow approach: A case series.

Six cases of posterior orbital mass lesions are described in which a suprabrow approach was utilized for transorbital craniotomy. This technique offers several advantages over traditional supraorbital and transcranial approaches to deep orbital tumors. The results were anatomically and cosmetically excellent in all cases. The surgical technique for transorbital craniotomy, along with its advantages and potential complications, are explained in detail. The clinical presentation, radiological features of the lesions, postoperative outcome, and complications are discussed.