Search Results

You are looking at 1 - 10 of 34 items for

  • Author or Editor: William A. Friedman x
  • Refine by Access: all x
Clear All Modify Search
Restricted access

Obituary: Albert Loren Rhoton Jr., MD, 1932–2016

William A. Friedman

Restricted access

Temporary ventricular drainage and emergency radiotherapy in the management of hydrocephalus associated with germinoma

John M. Buatti and William A. Friedman

Object. The authors used an alternative strategy to avoid shunt placement for hydrocephalus associated with germinoma, and the ensuing complications.

Methods. Between 1998 and 2000, five patients presenting with germinomas of the pineal area and symptomatic obstructive hydrocephalus were treated with a novel strategy. On arrival, they underwent ventriculostomy placement and one of several surgical procedures to obtain tissue for diagnosis. Within several days of the initial diagnosis, stereotactically guided fractionated radiotherapy was started. All patients experienced rapid tumor shrinkage and resolution of hydrocephalus, allowing discontinuation of external ventricular drainage without the need for permanent shunting of cerebrospinal fluid. To date, follow up reveals 100% radiographically and clinically confirmed tumor control.

Conclusions. Prompt resolution of hydrocephalus and absence of complications make this a potentially valuable therapy for control of germinomas and their symptoms.

Restricted access

Stereotactic suboccipital transcerebellar biopsy under local anesthesia using the Cosman-Roberts-Wells frame

Technical note

Roberto Spiegelmann and William A. Friedman

✓ Previously reported suboccipital transcerebellar stereotactic biopsy methods, performed with the patient in the prone position, have required general endotracheal anesthesia. A technique is described for performing such biopsies with the patient in the lateral decubitus position, under local anesthesia. Phantom planning and routine computerized tomography graphics allow the selection of a safe entry point and intra-axial trajectory to the lesion. The time required for data acquisition and the operative procedure itself compares well with that of more routine biopsy techniques.

Restricted access

Percutaneous tunnel ventriculostomy

Summary of 100 procedures

William A. Friedman and John K. Vries

✓ External ventricular drainage is an important therapeutic adjunct in neurosurgical practice. Unfortunately, this procedure has been associated with a significant incidence of ventriculitis. A major source for many of these infections has been bacterial contamination of the tract of the ventricular catheter, at the site where it enters the scalp. To prevent this problem, the authors have devised a new ventriculostomy technique that involves tunneling the ventricular catheter through the scalp, between the dermis and the galea. One hundred consecutive procedures in 66 patients are analyzed in this paper. The average duration of drainage was 6.2 days. There were no infections subsequent to the insertion of the ventricular catheter in this group of patients.

Full access

Linear accelerator–based radiosurgery for vestibular schwannoma

William A. Friedman and Kelly D. Foote

Despite major advances in skull base surgery and microsurgical techniques, surgery for vestibular schwannoma (VS) carries a risk of complications. Some are inherent to general anesthesia and surgery of any type and include myocardial infarction, pneumonia, pulmonary embolism, and infection. Some are specific to neurosurgery in this area of the brain, and include hydrocephalus, cerebrospinal fluid leak, facial nerve paralysis, facial numbness, hearing loss, ataxia, dysphagia, and major stroke. Even in the hands of very experienced acoustic surgeons, these risks cannot be eliminated.

Radiosurgery provides an outpatient, noninvasive alternative for the treatment of small acoustic schwannomas. Initially radiosurgery was undertaken in “high-risk” patients, including the elderly, those with severe medical comorbidities, and those in whom tumors recurred after surgery. Additionally, a high rate of cranial nerve morbidity was reported. With improvements in dosimetry planning and dose selection, however, authors practicing at radiosurgical centers now report very low complication rates, as well as high tumor control rates.

In this report the authors specifically review the results of linear accelerator–based radiosurgery for VS and compare these outcomes with the best surgical alternatives.

Restricted access

Linear accelerator radiosurgery for arteriovenous malformations

William A. Friedman and Frank J. Bova

✓ Between May, 1988, and August, 1991, 80 patients with arteriovenous malformations (AVM's) were treated radiosurgically at the University of Florida. A mean dose of 1650 cGy was directed to the periphery of the lesion, which almost always corresponded to the 80% isodose line. The mean lesion diameter was 23 mm. Seventy-six patients were treated with one isocenter. Angiography, performed at 1 year after radiosurgery in 41 of the 48 eligible patients, revealed an overall complete thrombosis rate of 39%. The 1-year thrombosis rate was highest in those patients with relatively small AVM's. Angiography was performed at 2 years posttreatment in 21 of the 25 eligible patients, demonstrating an overall complete thrombosis rate of 81%. This incidence did not correlate with lesion size: that is, large lesions (up to 35 mm in diameter) seemed just as likely to thrombose. Two patients (2.5%) experienced hemorrhage at some time after radiosurgical treatment, and both recovered. Two patients (2.5%) have sustained mild, but permanent, radiation-induced neurological complications.

Restricted access

Linear accelerator radiosurgery for vestibular schwannomas

Jason P. Sheehan

Restricted access

Automatic artifact rejection during intraoperative recording of somatosensory evoked potentials

Technical note

J. Marc Simard and William A. Friedman

✓ A device is described that performs automatic artifact rejection for somatosensory evoked response analysis in intraoperative and other electrically noisy environments. Although based on amplitude discrimination, rejection is not triggered by the large stimulus-dependent voltage transients associated with somatosensory evoked potentials. The device readily interfaces with commercially available evoked potential equipment.

Restricted access

Radiosurgery for AVMs: Evaluating the Risks and Benefits

Restricted access

Linear accelerator radiosurgery for arteriovenous malformations: the relationship of size to outcome

William A. Friedman, Frank J. Bova, and William M. Mendenhall

✓ Between May, 1988 and August, 1993, 158 patients with arteriovenous malformations (AVMs) were treated radiosurgically at the University of Florida. A mean dose of 1560 cGy was directed to the periphery of the lesions, which had a mean volume of 9 cc (0.5 to 45.3 cc). One hundred thirty-nine of these individuals were treated with one isocenter. The mean follow-up interval was 33 months with clinical information available on 153 of these patients. Patients were followed until magnetic resonance (MR) studies suggested complete AVM thrombosis. An arteriogram was then performed, if possible, to verify occlusion status. If arteriography revealed any persistent nidus at 36 months posttreatment, the residual nidus was re-treated.

Outcome categories of AVMs analyzed included the following possibilities: 1) angiographic cure; 2) angiographic failure; 3) re-treatment; 4) MR image suggested cure; 5) MR image suggested failure; 6) patient refused follow-up evaluation; 7) patient lost to follow-up study; or 8) patient deceased. The endpoints for success or failure of radiosurgery were as follows: angiographic occlusion (success), re-treatment (failure), and death due to AVM hemorrhage (failure). Fifty-six patients in this series reached one of the endpoints. Successful endpoints were seen in 91% of AVMs between 1 and 4 cc in volume, 100% of AVMs 4 to 10 cc in volume, and 79% of AVMs greater than 10 cc in volume.

The more traditional measure of radiosurgical success, percentage of angiograms showing complete obliteration, was obtained in 81% of AVMs between 1 and 4 cc in volume, 89% of AVMs between 4 and 10 cc in volume, and 69% of AVMs greater than 10 cc in volume. A detailed analysis of the relationship of all outcome categories to size is presented.