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Biomedical subjects

E Arbit

Publications and source records attributed to E Arbit.

At least 19 recordsLinked to original sources

Craniofacial resection for tumors involving the anterior skull base.

A consecutive series of 71 patients who underwent craniofacial resection between 1974 and 1990 for tumors that involved the anterior cranial base was reviewed. A variety of histologic diagnoses was present in this series. The most prevalent sites of origin included the nasal cavity, ethmoid sinus, and frontal sinus. Gross tumor removal was achieved in all patients, with 29 requiring orbital exenteration. Adjuvant radiation therapy was used in 25 patients. Two patients died of postoperative complications and 26 had complications that increased morbidity and length of the hospitalization. Five-year overall survival was 56%, with a median survival of 4.2 years. Local control was observed in 40 of 56 patients with negative margins and 9 of 15 patients with positive margins. There was no difference in survival between previously treated and untreated patients. Survival varied considerably among the various pathologic diagnoses. Survival was related to the extent of disease. Patients with either dural or brain invasion had significantly decreased survival compared to those with no dural invasion. The operative procedure is safe, with acceptable morbidity and mortality, and offers respectable survival in properly selected patients.

Adolescent

Resection of brain metastases from non-small-cell lung carcinoma. Results of therapy. Memorial Sloan-Kettering Cancer Center Thoracic Surgical Staff.

The treatment of patients with a solitary brain metastasis has been evolving, with most centers recommending resection in patients with good performance status. To evaluate the results of resection of brain metastases from non-small-cell lung cancer, we reviewed our 16-year experience with 185 consecutive patients undergoing resection of brain metastases from 1974 to 1989, inclusive. There were 89 men and 96 women; ages ranged from 34 to 75 years (median 54). Sixty-five (35%) had synchronous and 120 (65%) metachronous brain metastases. Discounting the brain metastasis, 68 patients (37%) had stage I, 13 (7%) stage II, 62 (33%) stage IIIA, 30 (16%) stage IIIB, and 12 (6%) stage IV carcinoma. There was no significant difference in age, locoregional stage (TN), or histologic features in patients with synchronous versus metachronous lesions. The overall survival rates (n = 185) were as follows: 1 year, 55%; 2 years, 27%; 3 years, 18%; 5 years, 13%; and 10 years, 7% (median 14 months). There was no significant difference in survival between patients with synchronous and metachronous lesions. To evaluate the impact of locoregional stage and treatment of the primary site, we analyzed only those patients with synchronous brain metastases. Multivariate analysis demonstrated that locoregional stage had no significant effect on survival (p = 0.97), but complete resection of the primary disease significantly prolonged survival (p = 0.002). Therefore complete resection, and not stage, of the locoregional primary lesion is the primary determinant of survival in patients undergoing resection of brain metastases from non-small-cell lung cancer.

Actuarial Analysis

Measurement of brain tissue specific gravity using pycnometry.

In this paper we introduce and characterize pycnometry, a method used to measure fluid density, for determining a tissue's specific gravity. It uses a 2-ml glass pycnometer filled with distilled water to determine a tissue sample's displacement volume. The tissue's density is determined when it's weight is divided by this volume and specific gravity is computed by dividing the tissue density by the density of water. Pycnometry was validated using pre-calibrated glass, specific gravity standards over the range 1.03-1.26, and compared to the density gradient method using rat brain tissue. We observed that the specific gravity values obtained using pycnometry were highly correlated with the specific gravity standards (slope = 1.0107, r = 0.996) and with the density gradient column when tissue volumes larger than 0.120 ml were used with the pycnometer (slope = 1.0707, r = 0.9826). Good correlation was also observed between percent water content values computed using the Nelson equation with pycnometry or density gradient specific gravity values versus the measured percent water content values obtained with the wet weight/dry weight method. Pycnometry is an accurate, reproducible technique to measure tissue specific gravity and brain edema and is best suited for use in a laboratory that engages sporadically in brain edema measurement.

Animals

Paraspinal tumors: techniques and results of brachytherapy.

Because of their proximity to nerve roots and the spinal cord, it is frequently difficult to achieve complete resection of paraspinal tumors. We have used brachytherapy in an attempt to prevent local recurrence and its associated neurological sequelae. This report analyzes our experience with 35 patients to determine the feasibility, optimal techniques, and efficacy of this approach. The tumor types were non small-cell lung cancer (18), sarcomas (9), and other tumor types (8). Temporary, single plane implants using Ir-192 (median minimum peripheral dose 3000 cGy) were used in 21 patients, and permanent I-125 implants were used in 14 cases (median matched peripheral dose 12,500 cGy). Local control was achieved in 51% (18/35). However, local control was poor when lung cancers were implanted and in cases where the dura was exposed. Radiation myelitis did not occur despite the combined effects of previous external beam radiotherapy (N = 21) and brachytherapy. Our experience demonstrates that combined surgery and paraspinal brachytherapy can be performed with acceptable toxicity and is reasonably effective in preventing local relapse and its neurologic sequelae, particularly for tumors other than lung cancers.

Brachytherapy

Percutaneous radiofrequency neurolysis guided by computed tomography for the treatment of glossopharyngeal neuralgia.

The technique of radiofrequency neurolysis guided by computed tomography for the treatment of glossopharyngeal neuralgia is described. This technique has the advantage of being performed in a neutral head position, affording excellent visualization of the jugular foramen, and also of simulating radiographically the precise trajectory of the electrode. This procedure is of particular value in treating patients with neoplastic disease and those in whom the outlines of the jugular foramen are poorly visualized on fluoroscopy or plain radiography.

Aged

Tension pneumocephalus: treatment with controlled decompression via a closed water-seal drainage system. Case report.

The successful treatment of a patient with tension pneumocephalus by controlled decompression via external drainage is described. The advantage of the technique includes the immediate release of high pressure and the capability of maintaining constant low pressure to enable and facilitate sealing of dural tears. The method has been used in three other patients, leading to resolution of the tension pneumocephalus without recurrence or other complications.

Cerebrospinal Fluid Shunts

Measurement of brain tissue density using pycnometry.

A novel method to measure specific gravity (SG) of tissues, pycnometry (PYC), is described. This method utilizes a 2ml glass pycnometer filled with distilled H2O to determine the displacement volume of a tissue sample and an equation to compute SG from the sample's weight and the pycnometer's weight before and after adding the sample. The PYC method was validated using glass SG standards over the range 1.02-1.26, and against the column density gradient (DG) method using brain tissue from 250-300 g male rats. Factors which affect PYC accuracy, i.e. sample size, were also evaluated. Our results indicate that PYC SG values are highly correlated with the glass SG standards (slope = 1.0107, r = 0.9955, p less than 0.001), and highly correlated with DG when approximately 0.120 ml tissue samples are used in the pycnometer. The DG method was preferable to the PYC method, however, when small tissue samples, i.e. 0.60 ml or less, were used.

Animals

The effect of the aminosteroid U-78517G on peritumoural brain oedema.

U-78517G belongs to a novel group of compounds-aminosteroids (AS) which are potent inhibitors of central nervous system tissue lipid peroxidation and are devoid of classical glucocorticoid and mineralocorticoid activities. The AS have been found to possess cerebral protective properties against ischaemia, ischaemic oedema, trauma to the cerebrum and spinal cord and in sub-arachnoid hemorrhage. The possible efficacy of U-78517G in attenuating peritumoural oedema was examined in rats harbouring cerebral 9L gliosarcomas. 19 Sprague-Dawley rats were implanted intracranially with 9L gliosarcoma cells. On day 14 post implantation rats were randomized to control (no treatment n = 10) and AS treated animals (n = 9). On day 20 animals were sacrificed and six brain samples per rat were examined for the percentage of water content. Oedema was assessed with the wet/dry weight technique. The AS treated animals were found to have a significant increase in peritumoural oedema (+1.38%, P less than 0.001) possibly related to an increase in cerebral blood flow associated with AS treatment. Further studies are, however, underway to precisely clarify this unexpected observation.

Animals

Spinal cord blood flow in the rat under normal physiological conditions.

Regional spinal cord blood flow (SCBF) was measured in a group of rats under conditions of normothermia, normocarbia, normoxia, and normal blood pressure, using the hydrogen clearance technique. Regional SCBF in the cervical white matter was 26.8 +/- 1 (SE) ml/100 g/min and in the cervical gray matter 53.6 +/- 2.5; in the thoracic white matter it was 22.2 +/- 2.4 ml/100 g/min and in the thoracic gray matter 41.2 +/- 12/6 ml/100 g/min; and in the lumbar gray matter it was 52.3 +/- 1.9 ml/100 g/min. The effect of changes in blood pressure on SCBF (autoregulation) was investigated in nine rats. We have observed that SCBF remains relatively constant in the blood pressure range of 45 to 165 mm Hg and assumes a passive flow below or above this range.

Animals

Modified open thoracic rhizotomy for treatment of intractable chest wall pain of malignant etiology.

We describe the surgical technique of modified open thoracic rhizotomy for treatment of intractable chest wall pain of malignant etiology. In a series of 14 patients, 9 (64%) had an excellent result, 4 (29%) had a good result, and 1 (7%) had a poor result. Successful palliation was made possible by identification with computed tomographic scan or magnetic resonance imaging of the nerve roots involved. Pain control lasted in most patients until death (median, 22 weeks; range, 6 to 45 weeks). The extrathecal procedure described has certain advantages over intradural transection of nerve roots. Indications for performing this procedure are discussed along with other therapeutic options.

Adult

Patterns of failure following treatment for glioblastoma multiforme and anaplastic astrocytoma.

Recurrence patterns of glioblastoma multiforme (25) and anaplastic astrocytoma (9) were studied using CT scans of 34 patients who received all or a portion of their surgical treatment at Memorial Sloan-Kettering Cancer Center from January 1983 through February 1987. Thirty-two patients presented with unifocal tumors and two with multifocal tumors. All patients received radiation therapy following initial surgery. Eighteen patients who underwent re-operation following CT evidence of recurrence had histologic verification of recurrent tumor; sixteen patients had radiographic evidence of recurrence only. Seventy-eight percent (25/32) of unifocal tumors recurred within 2.0 cm of the pre-surgical, initial tumor margin, defined as the enhancing edge of the tumor on CT scan. Fifty-six percent (18/32) of tumors recurred within 1.0 cm of the initial tumor margin. Tumors for which a gross total resection was accomplished tended to recur closer to the initial tumor margin than did subtotally resected tumors (p greater than 0.1). Extensive pre-operative edema was associated with a decreased distance between initial and recurrent tumor margins. Large tumors were generally not more likely to recur further from the initial tumor margin than were smaller tumors. No unifocal tumor recurred as a multifocal tumor. Only one tumor (initially near the midline) recurred in the contralateral hemisphere. The findings support the use of partial brain irradiation for post-operative treatment of glioblastoma multiforme and anaplastic astrocytomas, and may help to determine the most appropriate treatment volume for interstitial irradiation.

Adult

Inability of computed tomography appearance of recurrent malignant astrocytoma to predict survival following reoperation.

Computed tomographic (CT) scans of 39 patients who underwent reoperation for recurrent malignant astrocytoma at Memorial Sloan-Kettering Cancer Center from 1980 through 1987 were reviewed and correlated with the patients' clinical course. Histologic diagnosis (anaplastic astrocytoma v glioblastoma multiforme) had a statistically significant impact on survival following reoperation (P = .038). Patients with high preoperative performance status (P = .29), total resection by postoperative CT scan (P = .15), and frontal lobe tumors (P = .17) tended to survive longer following reoperation. The size of the tumor at the time of recurrence did not correlate with survival following reoperation. Patients with a small amount of peritumoral edema at the time of recurrence tended to survive longer, but the effect was small (P = .16). Prognosis following reoperation cannot be accurately predicted on the basis of tumor appearance on CT scan.

Adolescent

Intraoperative measurement of cerebral and tumor blood flow with laser-Doppler flowmetry.

A new technique, laser-Doppler flowmetry, has been used intraoperatively to measure blood flow responses in normal brain tissue and brain tumor to blood pressure and arterial blood gas alterations. We have observed that blood flow is reduced in most cerebral tumors, and that most tumors retain the normal response to changes in arterial blood gas; however, these responses are varied. One group of tumors in our study demonstrated an autoregulatory capacity; a second behaved passively--that is, blood flow changes followed blood pressure--while a third showed no response.

Animals