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Biomedical subjects

L D Lunsford

Publications and source records attributed to L D Lunsford.

At least 73 records · Page 4Linked to original sources
PubMed1999

Use of cytological preparations for the intraoperative diagnosis of stereotactically obtained brain biopsies: a 19-year experience and survey of neuropathologists.

OBJECT: The goals of this study were to analyze the accuracy of cytological techniques, consisting of touch and smear preparations, for the intraoperative diagnosis of stereotactically obtained brain biopsy samples, and to determine the prevalence of the use of these methods among neuropathologists. METHODS: A survey regarding preferred methods for intraoperative diagnosis of stereotactically obtained brain biopsy samples was completed by 92 (62%) of 148 neuropathologists. Twenty-three percent of respondents chose frozen-section examination alone; 13% chose one or more cytological methods alone; and the remainder (64%) chose a combination of frozen-section examination and cytology. At the University of Pittsburgh, the neuropathology records for all stereotactic brain biopsies performed from May 1979 through May 1998 were retrospectively reviewed. Of the 946 stereotactic brain biopsies, 316 cases were excluded because the intraoperative neuropathological consultation was not recorded. Thirty-five cases were excluded because frozen-section examinations were performed. Therefore, a total of 595 cases were suitable for analysis. Intraoperative cytological investigation correlated with the final diagnosis in 90% of cases (52% complete correlation and 38% partial correlation). In 11% of cases there was no correlation between the intraoperative and final diagnoses. Intraoperative diagnoses were most accurate in cases of abscess, germinoma, lymphoma, metastasis, and malignant glioma. Overall, 91% of biopsy specimens were diagnostic when examined using the paraffin-embedded section technique. The sensitivity of cytological preparations in detecting a diagnostic specimen was 96% and the specificity in detecting a nondiagnostic specimen was 75%. CONCLUSIONS: Intraoperative cytological preparations correlated with the final diagnoses in 90% of stereotactic biopsies and had a 96% sensitivity in detecting diagnostic specimens. The highest rate of correlation was noted in cases of abscess, germinoma, lymphoma, metastasis, and malignant glial tumor.

Biopsy↗
PubMed1999

Stereotactic radiosurgery for brainstem metastases.

OBJECT: Brainstem metastases portend a dismal prognosis. Surgical resection is not part of routine management and radiation therapy has offered little clinical benefit. Radiosurgery provides a safe and effective treatment for many patients with brain metastasis, but its role in the brainstem has not been evaluated. In this study the authors examine the role of radiosurgery in the treatment of brainstem metastases. METHODS: The authors reviewed the outcomes after stereotactic radiosurgery in 26 patients with 27 brainstem metastases. Tumor locations included the pons (21 tumors) and midbrain (six tumors): 14 patients had additional tumors in other locations. Twenty patients presented with brainstem signs. The median dose to the tumor margin was 16 Gy (range 12-20 Gy). Twenty-four patients received fractionated whole-brain radiation therapy (WBRT) and 12 underwent additional chemotherapy or immunotherapy. The median follow-up time in these patients was 9.5 months (range 1-43 months). After radiosurgery, the local control rate in brainstem tumors was 95%. In one patient in whom the tumor initially decreased in size, tumor enlargement was seen 7 months later. The median survival time was 11 months after diagnosis and 9 months after radiosurgery. Thirteen patients improved, 10 were stable, and three deteriorated. Eventually, 22 patients died, 18 of progression of their extracranial disease, three of new tumor growth (including one hemorrhage into a new brain metastasis), and one of extracranial disease plus new brain tumor growth. CONCLUSIONS: Although they have slightly lower than the expected survival rates of patients with nonbrainstem tumors, patients with brainstem metastases may achieve effective palliation after stereotactic radiosurgery and WBRT.

Adult↗
PubMed1999

Iatrogenic pneumocephalus secondary to intravenous catheterization. Case report.

The presence of pneumocephalus in a patient without a history of undergoing intracranial or intrathecal procedures is a significant radiographic finding that portends a violation of the dural barrier or the presence of infection. The authors report a case of iatrogenic pneumocephalus that confounded the evaluation of a patient with unrelated neurological disorders, resulting in unnecessary transfer of the patient and utilization of medical resources. A review of 100 sequential computerized tomography scans obtained in patients for any indication in the emergency department revealed a 6% incidence of iatrogenic intravenous pneumocephalus. Computerized tomography scans revealing pneumocephalus had been obtained for altered mental status, focal motor deficit, seizure, and trauma. More careful intravenous catheterization and recognition of the condition on imaging may avoid similar problems.

Catheterization, Peripheral↗
PubMed1999

The radiobiology of radiosurgery.

Radiosurgery is the precise and complete destruction of a chosen target containing healthy or pathological cells, without significant concomitant or late radiation damage to adjacent cells. This article discusses briefly the many uses of radiobiology and considers variables in the treatment, such as dose rate, dose homogeneity, and the issue of possible pharmacological radioprotection for radiosurgery. Comparisons between radiosurgery and fractionation are also made.

Brain↗
PubMed1999

Dose selection in stereotactic radiosurgery.

Selection of the prescription dose for radiosurgery is the final step in treatment planning. Dose selection should take into account the expectation of treatment success (i.e., tumor control, arteriovenous malformation [AVM] obliteration, and so forth) and complication risks at various doses. Accurately predicting complication risks for individual patients is a complex process that is highly dependent on the radiosurgery treatment volume, the target location, and the nature of the target tissue. Dose-response data for desired outcomes of radiosurgery are sparse and difficult to interpret for most indications, with perhaps the exception of AVM obliteration. This article reviews the principles governing dose-selection and the evolving body of data guiding dose selection in radiosurgery.

Brain↗
PubMed1999

Can hearing improve after acoustic tumor radiosurgery?

Advances in noninvasive diagnostic techniques have enabled physicians to diagnose acoustic tumors early, while hearing is still present. Applications of advanced operative techniques have allowed surgeons to decrease progressively the operative mortality to virtually zero, to save facial nerve function in a large number of patients, and even to preserve serviceable hearing in selected patients. Documented improvement in hearing after acoustic tumor surgery is rare. During the last decade, stereotactic radiosurgery has evolved as a noninvasive surgical option for acoustic tumors. Hearing improvement after radiosurgery has not been reported. The authors observed hearing improvement in 21 out of 487 patients who had radiosurgery during a 10-year interval. This article reviews their experience of hearing improvement after radiosurgery and suggests possible reasons that hearing can not only be retained but also improved in selected patients.

Adult↗
PubMed1999

Stereotactic radiosurgery for meningiomas.

The indications for and results after meningioma radiosurgery results are discussed. Particular emphasis is placed on longer-term results, the evolution of technique, complications, and recommendations regarding the role of radiosurgery together with other management strategies.

Adolescent↗
PubMed1999

Stereotactic radiosurgery for management of deep brain cavernous malformations.

The indications for stereotactic radiosurgery for patients with cavernous malformations of the brain are discussed. Specific reference is made to technique and dose selection and to the results and potential complications of this approach. Radiosurgery is an alternative to microsurgical resection for some patients with malformations in high-risk brain locations.

Adolescent↗
PubMed1998

Long-term outcomes after radiosurgery for acoustic neuromas.

BACKGROUND: Stereotactic radiosurgery is the principal alternative to microsurgical resection for acoustic neuromas (vestibular schwannomas). The goals of radiosurgery are the long-term prevention of tumor growth, maintenance of neurologic function, and prevention of new neurologic deficits. Although acceptable short-term outcomes have been reported, long-term outcomes have not been well documented. METHODS: We evaluated 162 consecutive patients who underwent radiosurgery for acoustic neuromas between 1987 and 1992 by means of serial imaging tests, clinical evaluations, and a survey between 5 and 10 years after the procedure. The average dose of radiation to the tumor margin was 16 Gy, and the mean transverse diameter of the tumor was 22 mm (range, 8 to 39). Resection had been performed previously in 42 patients (26 percent); in 13 patients the tumor represented a recurrence of disease after a previous total resection. Facial function was normal in 76 percent of the patients before radiosurgery, and 20 percent had useful hearing. RESULTS: The rate of tumor control (with no resection required) was 98 percent. One hundred tumors (62 percent) became smaller, 53 (33 percent) remained unchanged in size, and 9 (6 percent) became slightly larger. Resection was performed in four patients (2 percent) within four years after radiosurgery. Normal facial function was preserved in 79 percent of the patients after five years (House-Brackmann grade 1), and normal trigeminal function was preserved in 73 percent. Fifty-one percent of the patients had no change in hearing ability. No new neurologic deficits appeared more than 28 months after radiosurgery. An outcomes questionnaire was returned by 115 patients (77 percent of the 149 patients still living). Fifty-four of these patients (47 percent) were employed at the time of radiosurgery, and 37 (69 percent) remained so. Radiosurgery was believed to have been successful by all 30 patients who had undergone surgery previously and by 81 (95 percent) of the 85 who had not. Thirty-six of the 115 patients (31 percent) described at least one complication, which resolved in 56 percent of those cases. CONCLUSIONS: Radiosurgery can provide long-term control of acoustic neuromas while preserving neurologic function.

Adult↗
PubMed1998

Stereotactic radiosurgery for cerebral metastatic melanoma: factors affecting local disease control and survival.

PURPOSE: The development of a brain metastasis represents an ominous event for patients with malignant melanoma. We evaluated results after stereotactic radiosurgery (SR) for patients with metastastic melanoma to identify patient outcomes and factors for survival. METHODS: The authors reviewed the management results of 60 consecutive patients with melanoma metastases, with a total of 118 melanoma brain metastases, undergoing SR during a 9-year interval. Of these, 51 also had whole-brain radiation therapy (WBRT). A total of 118 tumors of mean volume of 2.95 ml (range, 0.1-25.5 ml) were treated by SR with a mean margin dose of 16.4 Gy (range, 10 to 20 Gy). Univariate and multivariate analyses were used to determine significant prognostic factors affecting survival in 60 patients. RESULTS: Median survival was 7 months after SR in all 60 patients and 10 months from brain tumor diagnosis (mean follow-up period, 9.3 months). Lack of active systemic disease and a solitary metastasis were associated with improved survival in multivariate analysis (median, 15 months). The imaging-defined local control rate of evaluable tumors (n = 72) was 90% (disappearance = 11%, shrinkage = 44%, and stable = 35%). Local recurrence developed in 7 patients and remote brain disease developed in 14 patients. WBRT combined with radiosurgery did not improve survival nor local tumor control. New brain metastases developed less often when WBRT was added to SR (23% vs. 44%), but this difference was not significant. Only 4 patients (7%) died from progression of a radiosurgery-managed tumor. No patient developed a delayed radiation-related complication, but 3 patients developed delayed intratumoral hemorrhage at the radiosurgery site, 2 of whom had new symptoms. CONCLUSIONS: Stereotactic radiosurgery for melanoma brain metastasis is effective and is associated with few complications. The use of radiosurgery alone is an appropriate management strategy for many patients with solitary tumors.

Adolescent↗
PubMed1998

Outcomes after gamma knife radiosurgery in solitary acoustic tumors and neurofibromatosis Type 2.

Surgeons perform stereotactic radiosurgery as the main alternative to acoustic tumor (vestibular schwannoma) resection. The goals of radiosurgery include preservation of neurological function and prevention of tumor growth. Longer-term outcomes are not well documented for patients with solitary tumors or those with neurofibromatosis Type 2 (NF2). To define outcomes, the authors evaluated 462 consecutive patients with solitary acoustic tumors and 40 patients with NF2 (total of 45 tumors treated) who underwent radiosurgery between 1987 and 1998. Serial imaging studies, clinical evaluations, and a patient survey were performed. The average tumor margin dose was 15 Gy, and the mean transverse tumor diameter was 22 mm. In patients with solitary tumors, prior resection had been performed in 111 patients (24%); 27 patients experienced tumor recurrence after a "total resection." The clinical tumor control rate (no resection required) was 98%. In non-NF2 patients followed for at least 5 years, 100 tumors (61.7%) were smaller, 53 (32.7%) remained unchanged in size, and nine (5.6%) were slightly larger. Resection was performed in four patients (2.4%). Neurological deficits after radiosurgery all occurred within the first 28 months. The rates of facial and trigeminal neuropathy varied with radiosurgery technique. In patients with NF2, 16 tumors were smaller, 28 remained unchanged, and one enlarged (overall 98% control rate at median 3-year follow up). Resection was performed in three patients (7%). Useful hearing was preserved in six (43%) of 14 NF2 patients who had useful hearing before radiosurgery. Radiosurgery provided long-term tumor control associated with high rates of neurological function preservation. No further tumor surgery was necessary in 98% of patients with solitary tumors followed for a minimum of 5 years.

Journal Article↗
PubMed1998

Stereotactic radiosurgery for brain metastasis from renal cell carcinoma.

BACKGROUND: The authors evaluated results after stereotactic radiosurgery (SR) for brain metastases from renal cell carcinoma (RCC) and identified factors associated with improved survival and tumor control. METHODS: The authors reviewed the management results from a total of 52 RCC brain metastases in 35 consecutive patients who underwent stereotactic radiosurgery (SR) during a 9-year interval. Twenty-eight patients also underwent whole brain radiation therapy (WBRT). The mean tumor volume was 2.4 mL (range, 0.1-14.1 mL). The mean dose delivered to the tumor margin was 17 gray (Gy) (range, 13-20 Gy). Univariate and multivariate testing was performed to determine significant prognostic factors. RESULTS: The median survival was 11 months after SR and 14 months after brain tumor diagnosis. Only 2 patients (8%) died of progression of the irradiated tumor. Age < 55 years, lack of active systemic disease, and use of chemotherapy and/or immunotherapy after SR were significant favorable prognostic factors in multivariate testing. Post-SR imaging was evaluated in 26 patients (39 tumors). The local control rate from the 39 treated tumors imaged was 90% (tumor disappearance, 21%; tumor regression, 44%; and stable disease, 26%). Local recurrence developed in 3 patients (4 lesions) and remote brain disease in 12 patients. No patient developed a new focal neurologic deficit due to SR. Patients were classified into two groups: SR with and SR without WBRT. The addition of WBRT to SR did not improve survival. Distant failure occurred similarly in both groups (46% vs. 50%). WBRT combined with SR may contribute to local control, but did not prevent the development of new remote tumors. CONCLUSIONS: SR for brain metastasis from RCC results in brain disease control in the majority of patients and was associated with few complications. Early detection of brain metastases and treatment with SR provides extended quality survival.

Aged↗
PubMed1998

Stereotactic radiosurgery for chordoma and chondrosarcoma: further experiences.

PURPOSE: Skull base chordomas and chondrosarcomas pose management challenges owing to their critical location, locally aggressive nature, and high recurrence rate despite multimodality treatment. We used stereotactic radiosurgery as primary or adjuvant therapy to achieve safe and effective therapeutic irradiation. METHODS AND MATERIALS: At an average of 4 years (range 1-7), we evaluated 15 patients (nine with chordomas and six with chondrosarcomas) who had gamma-knife radiosurgery as an adjunct (13 patients) or as an alternative to microsurgical resection (two patients). Patient age varied from 7 to 70 years (mean 38). There was a distinct male preponderance (2:1). Thirteen patients had undergone between one and four resections. Using conformal radiosurgical planning, a maximum tumor dose of 24-40 Gy (mean 36) and a tumor margin dose of 12-20 Gy (mean 18) was given to a mean tumor volume of 4.6 ml. RESULTS: Eight patients showed clinical improvement, three remained stable, and four died. Two of the four patients who died had tumor progression remote from the radiosurgery volume; two patients died of unrelated disorders. Among 11 surviving patients, follow-up imaging showed a reduction in tumor size in five, no further tumor growth in five, and an increase in the size of the tumor in one. The patient with further tumor growth after radiosurgery subsequently underwent repeat resection. CONCLUSION: Despite the formidable management challenge posed by these neoplasms, our long-term evaluation has shown that radiosurgery is a safe and effective treatment for patients with small volume tumors.

Adolescent↗
PubMed1998

Analysis of neurological sequelae from radiosurgery of arteriovenous malformations: how location affects outcome.

PURPOSE/OBJECTIVE: To elucidate how the risks of developing temporary and permanent neurological sequelae from radiosurgery for arteriovenous malformations (AVM) are related to AVM location, the addition of stereotactic magnetic resonance (MR) imaging to angiographic targeting, and prior hemorrhage or neurological deficits. MATERIALS AND METHODS: We evaluated follow-up imaging and clinical data in 332 AVM patients who received gamma knife radiosurgery at the University of Pittsburgh between 1987 and 1994. All patients had regular clinical or imaging follow-up for a minimum of 2 years (range: 24-96 months, median = 45 months). There were 83 patients with MR-assisted planning, 187 with prior hemorrhages, and 143 with prior neurological deficits. RESULTS: Symptomatic postradiosurgery sequelae (any neurological problem including headache) developed in 30 (9%) of 332 patients. Symptoms resolved in 58% of patients within 27 months with a significantly greater proportion (p = 0.006) resolving in patients with Dmin < 20 Gy vs. > or = 20 Gy (89 vs. 36%). The 7-year actuarial rate for developing persistent symptomatic sequelae was 3.8%. We first evaluated the relative risks for different locations to construct a postradiosurgery injury expression (PIE) score for AVM location. Multivariate logistic regression analysis of symptomatic postradiosurgery sequelae identified independent significant correlations with PIE location score (p = 0.0007) and 12 Gy volume (p = 0.008), but with none of the other factors tested (p > 0.3), including the addition of MR targeting, average radiation dose in 20 cc, prior hemorrhage, or neurological deficit. We used these results to construct a risk prediction model for symptomatic postradiosurgery sequelae. The risk of radiation necrosis was significantly correlated with PIE score (p < 0.048), but not with 12-Gy volume. CONCLUSION: The risks of developing complications from AVM radiosurgery can be predicted according to location with the PIE score, in conjunction with the 12-Gy treatment volume. Further study of factors affecting persistence of these sequelae (progression to radiation necrosis) is needed.

Analysis of Variance↗
PubMed1998

Gamma knife radiosurgery for trigeminal neuralgia: results and expectations.

BACKGROUND: Trigeminal neuralgia is a disabling pain syndrome responsive to both medical and surgical therapies. Stereotactic radiosurgery using the gamma knife can be used to inactivate a specified volume in the brain by cross firing 201 photon beams. We evaluated pain relief and treatment morbidity after trigeminal neuralgia radiosurgery. METHODS: All evaluable patients (n = 106) had medically or surgically refractory trigeminal neuralgia. A single 4-mm isocenter of radiation was focused on the proximal trigeminal nerve just anterior to the pons. For follow-up an independent physician who was unaware of treatment parameters contacted all patients. RESULTS: After radiosurgery, 64 patients (60%) became free of pain and required no medical therapy (excellent result), 18 (17%) had a 50% to 90% reduction (good result) in pain severity or frequency (some still used medications), and 9 (9%) had slight improvement. At last follow-up (median, 18 months; range, 6-48 months), 77% of patients maintained significant relief (good plus excellent results). Only 6 (10%) of 64 patients who initially attained complete relief had some recurrent pain. Radiosurgery dose (70-90 Gy), age, surgical history, or facial sensory loss did not correlate with pain relief. Poorer results were found in patients with multiple sclerosis. Twelve patients developed new or increased facial paresthesias after radiosurgery (10%). No patient developed anesthesia dolorosa. There was no other procedural morbidity. CONCLUSIONS: Gamma knife radiosurgery is a minimally invasive technique to treat trigeminal neuralgia. It is associated with a low risk of facial paresthesias, an approximate 80% rate of significant pain relief, and a low recurrence rate in patients who initially attain complete relief. Longer-term evaluations are warranted.

Adult↗
PubMed1998

Stereotactic radiosurgery for tentorial meningiomas.

Radical microsurgical resection is the procedure of choice for tentorial meningiomas. Despite advances in microsurgery, tentorial meningiomas continue to challenge surgeons and patients. To evaluate the response of tentorial meningiomas, we evaluated 41 patients who had Gamma knife stereotactic radiosurgery during a 9 year period. Patient age varied from 32 to 79 years. Headache, trigeminal neuralgia, or facial paraesthesia were the most common presenting symptoms. Sensory deficits in the distribution of the trigeminal nerve were the most common finding. Eighteen patients (44%) had undergone between 1 and 5 (mean, 1.9) resections prior to radiosurgery; 23 had tumors diagnosed by neuroimaging. The average tumor diameter in this series was 20 mm. The maximum tumor dose varied from 24 to 40 Gy (mean, 30.5 Gy), and the tumor margin dose varied from 12 to 20 Gy (mean, 15.3 Gy). During the average follow-up interval of 3 years (range, 1-8 years), 19 patients had clinical improvement, 20 remained stable, and 2 patients deteriorated. Follow-up imaging showed a reduction in tumor size in 18 patients, no further tumor growth in 22, and an increase in tumor size in one (overall tumor control rate of 98%). Stereotactic radiosurgery using the Gamma Knife was a safe and effective primary or adjuvant treatment for patients with tentorial meningiomas.

Adult↗