Central neurocytoma: case report of an 81-year-old and histopathologic findings.

Central Neurocytomas are rare and usually benign tumors found primarily in the lateral ventricles of the brain. Central Neurocytomas are composed of uniform round cells exhibiting neuronal differentiation and are found almost exclusively in young adults between 15 and 60 years of age. The authors report the case of an 81-year-old man with a history of severe psychosis and depression, who presented with progressive confusion and ataxia likely unrelated to a central neurocytoma of his right lateral ventricle. The patient underwent a stereotactic biopsy of the lesion, followed by Gamma Knife radiosurgery. Histopathology showed immunohistological staining for synaptophysin, neuron specific enolase (NSE) and neuronal nuclear antigen (NeuN). A review of published literature on central neurocytomas revealed that this tumor occurs most frequently in young adults with a median age between 25 and 30 years. This pathology has never been reported in patients over the age of 80. Gamma Knife radiosurgery was successful in decreasing the tumor volume by 20% at the four month follow-up, but the fact that the patient died of unrelated occurrences in the elderly cannot be ruled out. Patients with central neurocytomas commonly present with obstructive hydrocephalus and immediate treatment may be necessary to tide over urgent situations.

The treatment of movement disorders using Gamma Knife stereotactic radiosurgery.

In this era of modern neurosurgery, we are able to provide adequate amelioration of disabling symptoms for the small subset of patients who have conditions that may make them unacceptable candidates for invasive stereotactic neurosurgical intervention. Gamma Knife radiosurgical thalamotomy is an effective and useful alternative to invasive radiofrequency techniques for patients at high surgical risk. The mechanical accuracy of the gamma unit combined with the anatomical accuracy of high-resolution magnetic resonance imaging makes radiosurgical lesioning safe and precise.

Gamma knife radiosurgery for thalamotomy in parkinsonian tremor: a five-year experience.

OBJECT: Certain patients, for example, elderly high-risk surgical patients, may be unfit for radiofrequency thalamotomy to treat parkinsonian tremor. Some patients, when given the opportunity, may choose to avoid an invasive surgical procedure. The authors retrospectively reviewed their experience using gamma knife radiosurgery for thalamotomies in this patient subpopulation: 1) to determine the efficacy of the procedure; 2) to see if there is a dose-response relationship; 3) to review radiological findings of radiosurgical lesioning; and 4) to assess the risks of complications. METHODS: Radiosurgical nucleus ventralis intermedius thalamotomy using the gamma knife unit was performed to make 38 lesions in 24 men and 10 women (median age 73 years, range 58-87 years) over a 5-year period. A median radiation dose of 130 Gy (range 100-165 Gy) was delivered to 38 nuclei (four patients underwent bilateral thalamotomy) using a single 4-mm collimator following classic anatomical landmarks. Twenty-nine lesions were made in the left nucleus ventralis intermedius thalamus for right-sided tremor. Patients were followed for a median of 28 months (range 6-58 months). Independent neurological evaluation of tremor based on the change in the Unified Parkinson's Disease Rating Scale tremor score was correlated with subjective patient evaluation. Comparison was made between a subgroup of patients in whom "low-dose" lesions were made (range 110-135 Gy, mean 120 Gy) and those in whom "high-dose" lesions were made (range 140-165 Gy, mean 160 Gy) for purposes of dose-response information. Four thalamotomies (10.5%) failed, four (10.5%) produced mild improvement, 11 (29%) produced good improvement, and 10 (26%) produced excellent relief of tremor. In nine thalamotomies (24%) the tremor was eliminated completely. The median time to onset of improvement was 2 months (range 1 week-8 months). Concordance between an independent neurologist's evaluation and that of the patient was statistically significant (p < 0.001). Two patients who underwent unilateral thalamotomy experienced bilateral improvement in their tremor. There were no neurological complications. There was better tremor reduction in the high-dose group than in the low-dose group (p < 0.04). CONCLUSIONS: Although less effective than other stereotactic techniques, gamma knife radiosurgery for thalamotomy offers tremor control with minimal risk to patients unsuited for open surgery.

Safety of intrastriatal neurotransplantation for Huntington's disease patients.

Fetal neural transplantation has been shown to be a feasible, safe, and according to a number of recent reports, effective treatment for Parkinson's disease (PD). Fetal striatal transplantation may be as feasible, safe, and effective a treatment for Huntington's disease (HD), a disorder for which there is currently no effective treatment. This report describes our experience with fetal striatal transplantation to adult striatum in three HD patients. Three moderately advanced, nondemented HD patients received transplantation of fetal striatal tissue. The striatal precursor was selectively obtained from the lateral ganglionic eminence. Each patient received bilateral grafts from five to eight donors, placed into the caudate nucleus (one graft on each side) and the putamen (four grafts on each side). All three patients had HD as documented by family history, DNA heterozygosity (17-20 and 48-51 repeats), magnetic resonance imaging (MRI) revealing striatal atrophy, and 2-deoxyglucose positron emission tomography revealing striatal hypometabolism. All patients had been evaluated using the Unified Huntington's Disease Rating Scale and appropriate neuropsychological tests for at least 3 months prior to transplantation. One year following transplantation, MRI of all three patients revealed that the grafts survived and grew within the striatum without displacing the surrounding tissue. No patients demonstrated adverse effects of the surgery or the associated cyclosporin immunosuppression, nor did any patient exhibit deterioration following the procedure. The limited experience provided by these three patients indicates that fetal tissue transplantation can be performed in HD patients without unexpected complications.

Outcome following intrastriatal fetal mesencephalic grafts for Parkinson's patients is directly related to the volume of grafted tissue.

The effect of varying the volume of grafted fetal mesencephalic tissue was studied in patients with idiopathic Parkinson's disease in a single-blinded study. Evaluations were performed according to the Core Assessment Program for Intracerebral Transplantation and videotaped both prior to transplantation and in 3-month intervals after transplantation. One group, low-volume grafts (six subjects; mean age, 57.2 years), received ventral mesencephalon grafts from one to two donors with an approximate volume up to 20 mm3, while the second group, high-volume grafts (seven subjects; mean age, 59.5 years), received ventral mesencephalon grafts from three or more donors with an approximate volume of 24 mm3. Both groups of patients demonstrated significant improvement over presurgical baseline scores on all major parameters. The high-volume group had significantly greater improvements on all the UPDRS scores and also better performance on a variety of motor performance tasks over that seen among low-volume patients. These results indicate that variations of fetal graft volume do have an impact on clinical outcome.

Neuropsychological functioning following fetal striatal transplantation in Huntington's chorea: three case presentations.

Neurotransplantation has been proposed as a potential treatment for the neurodegenerative disorder of Huntington's disease (HD), which currently has no effective therapy. While patients with Parkinson's disease have received neurotransplantation, until recently no HD patients have undergone transplantation for HD with standardized evaluations of their progress following surgery. The current report presents the cognitive changes in three patients with HD who underwent bilateral transplantation of human fetal striatal tissue. As part of the pre- and postsurgical evaluation, all three patients were administered a neuropsychological battery sensitive to the cognitive effects of HD within 2 mo prior to surgery and at 4-6 mo following transplantation. Four to 6 mo subsequent to surgery, all patients demonstrated increased scores on some measures of cognitive functioning. However, the pattern of changes was not uniform across subjects. These findings suggest that fetal striatal transplantation may improve some of the cognitive symptoms associated with HD in the three reported patients.

Stereotactic radiosurgery for trigeminal neuralgia: a multiinstitutional study using the gamma unit.

A multiinstitutional study was conducted to evaluate the technique, dose-selection parameters, and results of gamma knife stereotactic radiosurgery in the management of trigeminal neuralgia. Fifty patients at five centers underwent radio-surgery performed with a single 4-mm isocenter targeted at the nerve root entry zone. Thirty-two patients had undergone prior surgery, and the mean number of procedures that had been performed was 2.8 (range 1-7). The target dose of the radiosurgery used in the current study varied from 60 to 90 Gy. The median follow-up period after radiosurgery was 18 months (range 11-36 months). Twenty-nine patients (58%) responded with excellent control (pain free), 18 (36%) obtained good control (50%-90% relief), and three (6%) experienced treatment failure. The median time to pain relief was 1 month (range 1 day-6.7 months). Responses remained consistent for up to 3 years postradiosurgery in all cases except three (6%) in which the patients had pain recurrence at 5, 7, and 10 months. At 2 years, 54% of patients were pain free and 88% had 50% to 100% relief. A maximum radiosurgical dose of 70 Gy or greater was associated with a significantly greater chance of complete pain relief (72% vs. 9%, p = 0.0003). Three patients (6%) developed increased facial paresthesia after radiosurgery, which resolved totally in one case and improved in another. No patient developed other deficits or deafferentation pain. The proximal trigeminal nerve and root entry zone, which is well defined on magnetic resonance imaging, is an appropriate anatomical target for radiosurgery. Radiosurgery using the gamma unit is an additional effective surgical approach for the management of medically or surgically refractory trigeminal neuralgia. A longer-term follow-up review is warranted.

Clinical study of fetal mesencephalic intracerebral transplants for the treatment of Parkinson's disease.

This study reports our findings from 22 patients (ages ranging from 42 to 73 yr; mean = 55.2) with recalcitrant idiopathic Parkinson's disease (PD) who received implants of fetal ventral mesencephalic tissue using an MRI-guided stereotactic procedure and who have been followed for at least 6 mo postoperatively, employing the guidelines established by the Core Assessment Program for Intracerebral Transplantations. Evaluations were videotaped and were performed both on and off levodopa medications. To date, we have seven patients with 24 mo, three with 18 mo, three with 12 mo, and nine with 6 mo post-surgical assessments. Comparing surgical outcomes to levels prior to fetal transplants we found: 1) mean levodopa levels were reduced 46% at 6 mo, 12% at 12 mo, 20% at 18 mo, and 54% at 24 mo; 2) Unified Parkinson's Disease Rating Scale (UPDRS) scores with patients on levodopa were improved by an average of 38% (6 mo), 50.2% (12 mo), 69.3% (18 mo), and 73.9% (24 mo), while off medication scores showed reductions ranging from 24.7% at 6 mo to 55.1% at 24 mo. Other measures, including Hoehn-Yahr staging, Activities of Daily Living, and dyskinesia rating scales, were also significantly improved following fetal transplants. Timed motor tasks (finger dexterity, supination-pronation, foot tapping, and Stand-Walk-Sit) performance also demonstrated highly significant improvements. Patient's self-rating scores indicated that the patients typically perceived substantial improvements in their condition. However, substantial variability in the improvements following surgery still persists and range from nominal improvements in performance to significant changes that can be classified as altering the overall lifestyle of the patients. To date, 4 of the 22 subjects were considered by the physicians to be nonresponders; that is, there were no clinically relevant improvements in these patients' conditions.

Lesion size following Gamma Knife treatment for functional disorders.

In this study we investigated the reproducibility and consistency of the size of radiosurgical lesions produced for functional disorders. The T1 gadolinium-enhanced magnetic resonance (MR) images of 56 patients treated for parkinsonism, pain, or other functional diseases were used to measure 140 lesion sizes at various times after radiosurgical treatment (1-26 months, mean: 11.3 months). Only the 4-mm collimator was used to create the lesions. The maximum dose ranged from 110 to 180 Gy (mean: 145 Gy). In 42 cases (78%), one isocenter was used to create the lesion. Thirteen lesions (20%) were created with two isocenters and in 1 case, three isocenters were used. Lesions were detectable on MR images as early as 30 days after treatment. The maximum lesion volume was reached after 6-12 months and ranged from nondetectable to more than 4,000 mm3. Larger lesion volumes were strongly associated with the use of more than one isocenter. In addition, maximum doses of 160 Gy or more increased the likelihood of producing lesions larger than expected. It is therefore concluded that the use of the Gamma Knife for the treatment of functional disorders is safest when single-isocenter shots with the 4-mm collimator and a maximum dose of less than 160 Gy are used.

Factors that enhance the likelihood of successful stereotactic treatment of brain abscesses.

Successful clinical outcomes are not achieved in all patients who undergo image-guided stereotactic surgery as the initial procedure in the management of brain abscess. We sought to define those factors related to management failure, so that the initial surgical approach could be selected using preoperative clinical or imaging criteria. We reviewed our twelve-year experience in 29 consecutive patients. Twenty-two (76%) patients had drainage of abscesses with purulent centers. Seven (24%) underwent lesion biopsy for diagnosis. Twelve patients (with abscesses > 3 cm in average diameter) underwent stereotactic insertion of drainage catheters. Ten patients (34%) had adverse risk factors including immunologic suppression after prior organ transplantation, chronic steroid therapy, prior antineoplastic chemotherapy, or retained foreign body. Microbiological identification of the causative organism was obtained in 22 patients; 6 patients had positive Gram stains without growth in culture (bacteriological diagnosis = 97%). Long-term clinical evaluation (up to 8.5 years, median 3 years) confirmed disease resolution after initial single-procedure stereotactic management in 21 patients (72%). Eventual abscess resolution occurred in an additional 6 patients (21%), all of whom required multiple procedures. Five patients died of complications of their systemic disease during the follow-up period. Fifteen of the 18 (83%) surviving patients who had no associated risk factors returned to their premorbid functional capacity. Factors associated with initial treatment failure included inadequate aspiration, lack of catheter drainage of larger abscesses, chronic immunosuppression, and insufficient antibiotic therapy.

Gamma knife radiosurgery for acoustic tumors: multivariate analysis of four year results.

In order to evaluate the results of radiosurgery for acoustic tumors and to identify optimum treatment parameters, an analysis of tumor control, as well as incidences of hearing loss, facial and trigeminal neuropathies was undertaken. Between August 1987 and August 1991, 134 patients with 136 acoustic tumors received stereotactic gamma knife radiosurgery at the University of Pittsburgh. Median follow-up was 24 months (range: 6-56 months). Tumor volumes ranged from 0.10 to 17.00 cm3 (median = 2.75 cm3). From one to ten isocenters were utilized per tumor treated (median = 3). Minimum tumor doses varied from 12 to 20 Gy (median = 17 Gy). The 4-year actuarial tumor control rate was 89.2 +/- 6.0%. Some degree of hearing (by pure tone audiometry) was preserved in 71.0 +/- 4.4% of patients. The actuarial rates for preservation of either pretreatment hearing level or useful hearing were 34.4 +/- 6.6% and 35.1 +/- 97% respectively. Respectively, the actuarial incidences of postradiosurgery facial and trigeminal neuropathies were 29.0 +/- 4.4% and 32.9 +/- 4.5%, respectively. No significant factors affecting tumor control were identified. Multivariate analysis identified a significantly increased risk of hearing loss in patients with neurofibromatosis (p = 0.0003) as well as decreased risks of facial and trigeminal neuropathies with both decreasing tumor diameter (p = 0.001) and increasing number of isocenters treated (p = 0.003). Radiosurgery is a safe and effective treatment for acoustic neuromas with acceptable morbidity that may be lowered by the use of multiple isocenter treatment techniques and by earlier treatment of small tumors.

Stereotactic radiosurgery of cavernous sinus meningiomas as an addition or alternative to microsurgery.

To evaluate the response of cavernous sinus meningiomas to stereotactic radiosurgery, we reviewed our 54-month experience with 34 patients. All patients underwent radiosurgery with a 201-source cobalt-60 gamma unit. Twenty-eight patients (82%) had previous histological confirmation of a meningioma (1 to 5 cranial base craniotomies per patient); 6 (18%) were treated on the basis of neuroimaging criteria alone. The single-fraction radiation tumor margin dose (10 to 20 Gy) was designed to conform to the irregular tumor volumes in all patients. The maximum radiation dose to the optic nerve or tract was reduced to 9 Gy in 31 patients. No patient had tumor growth (100% tumor control) during the follow-up interval (median, 26 mo). Tumor regression was observed in 56% of patients imaged at an average of 18 months. Eight patients (24%) improved clinically at follow-up examinations. Four patients developed new or worsened cranial nerve deficits during the follow-up interval; two had subsequent full improvement. No patient developed an endocrinopathy or new extraocular muscle paresis. Stereotactic radiosurgery, using multiple isocenter dosimetry facilitated by the gamma unit, is an accurate, safe, and effective technique to prevent the growth of tumors involving the cavernous sinus. Despite the proximity of such tumors to adjacent cranial nerves, complications were rare. The maximum length of hospital stay was 36 hours, and all patients returned to their preoperative employment status within 3 to 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiosurgery for vascular malformations of the brain stem.

The challenges associated with microsurgery of vascular malformations located in the midbrain, pons and medulla have promoted the development of alternative therapeutic techniques. To assess the efficacy and safety of radiosurgery in the management of brain stem vascular malformations we reviewed our 5-year experience in 50 patients evaluated between 4 and 51 months (mean, 25 months) after radiosurgery. Twenty-eight patients (56%) underwent gamma unit radiosurgery for symptomatic arteriovenous malformations (AVMs), and 22 patients (44%) for angiographically occult vascular malformations (AOVMs). Patients varied in age from 7 to 76 years (mean, 39 years). Forty-one patients (82%) had from 1 to 5 hemorrhages prior to gamma knife radiosurgery. Ten (20%) had one or two prior unsuccessful operations, and 37 (74%) presented with a neurological deficit. Of the patients with AVMs, 6 were considered Spetzler Grade III, and 22 (79%) Grade VI (inoperable: major component within the brain stem parenchyma). Forty-four malformations (88%) were adjacent to or within the midbrain and pons; the remainder involved the medulla. Average malformation diameters varied from 6 to 30.4 m (mean, 20.6; mean volume 4614 mm3). The minimal radiation dose to the margin of the malformations ranged from 12 to 25.6 Gy (mean, 18.9 Gy). Of the 28 patients with AVMs, 8 had follow-up angiograms at a minimum of 2-years after radiosurgery (or sooner if their MRIs suggested obliteration). Of these patients, 7 (88%) showed complete obliteration of their malformations. No patients with AOVMs rehemorrhaged if more than 15 months elapsed after radiosurgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Image-guided stereotactic management of non-AIDS-related cerebral infection.

Every neurosurgeon can appreciate Dandy's recognition that the drainage of brain abscesses causes trauma to the delicate parenchyma. Over the years, brain surgery has evolved toward management of problems by using less and less invasive techniques and thus gaining ever lower morbidity. Clearly, the advent of better imaging techniques has improved the outcome in patients afflicted with intracerebral infections. The combination of stereotaxy with these imaging techniques is contributing a "zero mortality" in the treatment of these infections. In our series of 29 consecutive patients with non-AIDS-related infections, no patient died as a direct result of a stereotactic surgical procedure. Two patients (7%) had new neurologic deficits after surgery. The only patient left with a permanent disability had a kidney allograft and subacute bacterial endocarditis. His condition deteriorated 6 hours after aspiration of a sterile abscess, when an intra-abscess hematoma was diagnosed and evacuated. In retrospect, this complication may have been avoided by less vigorous aspiration. Three of the four patients with nonviral infections who died were iatrogenically immunosuppressed for their organ transplants. These patients are difficult to treat, and given the current popularity of transplantation procedures, neurosurgeons will face more and more opportunistic infections. In general, the patients with abscesses did well. On the other hand, nonoperative mortality was extremely high for patients with viral encephalitides. This high mortality may have resulted from a delay in diagnosis and treatment or from the unavailability of highly effective antiviral agents at the time the biopsies were performed. The importance of early diagnosis and treatment of infection cannot be overemphasized. T.H. Flewett's warning about the management of HSE applies to the management of all cerebral infections: "It seems clear from everybody's published results [in the papers already given] if we wait to do biopsy until the clinical indications are unmistakable, we have waited so long that the patient, if he survives, will be left a severe neurological cripple." Because it is relatively noninvasive, stereotactic neurosurgery has been used increasingly to diagnose brain masses in patients with AIDS. We recommend its use for establishing diagnoses in all suspected cases of cerebral infection. We agree with Rosenblum et al: Empiric treatment of brain infections should be regarded as "radical." Such treatment should be reserved for patients who have an identifiable source of infection and causative organism or for patients who are clinically too unstable to undergo surgery.(ABSTRACT TRUNCATED AT 400 WORDS)