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Biomedical subjects

C Sen

Publications and source records attributed to C Sen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Surgical management of cavernous malformations of the brain stem.

Different surgical approaches to the brain stem with results of excision of brain stem cavernous malformations are reported. Nine patients with brain stem cavernous malformations were operated with six different approaches. The patients were evaluated neurologically, and by magnetic resonance imaging (MRI) examination. All patients had at least one and often more episodes of haemorrhage. Seven patients underwent the total removal of the malformation, without recurrence. One patient with a large medullary cavernoma had recurrence, but without further growth. One patient with a large pontomesencephalic malformation and partial resection, suffered rebleeding due to residual cavernoma. The mean follow-up period was 49 months (range 3-112). The results of surgery were excellent or good in eight patients, and poor (worsening) in one. It is concluded that surgical resection is recommended for the cavernous malformations of the brain stem which are symptomatic, have bled or are growing, and are approachable through one of the pial surfaces of the brain stem. Different skull base approaches are useful for this procedure. Radiosurgery is not recommended in such cases.

Adult↗
PubMed1997

Loss of heterozygosity in the retinoblastoma tumor suppressor gene in skull base chordomas and chondrosarcomas.

BACKGROUND: The retinoblastoma (Rb) gene is a well characterized tumor suppressor gene in which loss of heterozygosity has been implicated in a number of malignancies including osteosarcoma and breast carcinoma. Chordomas and chondrosarcomas are rare skull base neoplasms with a propensity for local recurrences, resistance to conventional radiotherapy, and a 5%-30% incidence of metastases. Except for the so called "chondroid chordoma," histologic features do not correlate with the clinical behavior or growth patterns of these tumors. No study to date has investigated what role tumor suppressor genes or oncogenes play in the development and continued growth of these rare neoplasms. METHODS: In order to evaluate the role of the retinoblastoma tumor suppressor gene in chordomas and chondrosarcomas we screened seven chordomas and two chondrosarcomas located at the skull base for loss of heterozygosity (LOH) of the Rb gene. Genomic DNA was extracted from tumor specimens as well as matched control tissue and utilizing a polymerase chain reaction technique, intron 17 and 20 were amplified from each specimen. The intron 17 product was then digested with the restriction endonuclease X ba1 followed by electrophoresis on a 1% agrose gel. The intron 20 amplified products were electrophoresed on a nondenaturing 6% polyacrylamide gel. RESULTS: We demonstrated LOH at intron 17 of the retinoblastoma gene in 2/7 chordomas and in 0/2 chondrosarcomas. The two chordomas possessing LOH were particularly aggressive tumors demonstrating extensive involvement of the skull base and rapid recurrences following radical resections. CONCLUSIONS: Alterations of the Rb gene may play a role in the growth of skull base chordomas with LOH of the Rb gene serving as a marker for more aggressive tumors. This report represents the first study evaluating the Rb gene in chordomas or chondrosarcomas and is the first report of allelic loss of the Rb gene in skull base chordomas.

Adolescent↗
PubMed1997

Results of surgery for head and neck tumors that involve the carotid artery at the skull base.

To evaluate the results of surgery in patients with head and neck cancers that involved the internal carotid artery at the skull base the authors retrospectively reviewed a consecutive series of 17 patients who underwent surgery at Mount Sinai Hospital over a 4-year period. In general, patients who underwent tumor resection with carotid preservation had less advanced disease (two of seven tumors were recurrences) than patients who underwent tumor resection with carotid sacrifice (seven of 10 tumors were recurrences). Of seven patients who underwent resection with carotid preservation, six had good outcomes (five patients alive in good condition, one dead at 2.2 years) and none had strokes. Of seven patients who underwent resection with carotid sacrifice and bypass, five had good outcomes (four alive in good condition, one dead at 2.5 years with no local recurrence) and two suffered graft occlusions that led to strokes, one of which was major and permanently disabling. Of three patients who underwent resection with carotid sacrifice and ligation without revascularization, there were no good outcomes: all three patients died within 6 months of surgery, two having suffered major permanently disabling strokes. The overall results (11 [65%] of 17 with good outcomes at an average follow-up period of 2.1 years) compared very favorably with historical nonsurgical controls. The authors conclude that tumor resection with carotid preservation carries the lowest risk of stroke and should usually be the treatment of choice. For patients with more advanced and recurrent disease, in whom it is believed that carotid preservation would prevent a safe and oncologically meaningful resection, carotid sacrifice with carotid bypass may be a useful treatment option. Carotid sacrifice without revascularization seems to be the treatment option with the least favorable results.

Aged↗
PubMed1997

Meningiomas involving the cavernous sinus: histological factors affecting the degree of resection.

Despite advances in the surgical treatment of meningiomas located at the skull base, surgery for meningiomas involving the cavernous sinus remains controversial. The controversy centers on whether complete resection of such a meningioma is possible while preserving cranial nerve function. To evaluate this question, the authors examined six patients with benign meningiomas involving the cavernous sinus. The pathological features of these tumors were evaluated and compared with the normal histoarchitecture of the cavernous sinus. The tendency of these tumors to be infiltrative is evident and this seems to occur along connective tissue planes within the cavernous sinus. This invasiveness can be explained by the peculiar structure of this region. The trigeminal nerve and ganglion seem to be particularly prone to invasion; this does not correlate with the degree of preoperative impairment of nerve function. Internal carotid artery invasion occurs frequently and can be seen even when there is no narrowing of the artery on arteriography. The pituitary gland can also be invaded by the tumor, which penetrates the thin dural barrier.

Adult↗
PubMed1997

Lipid metabolism alterations in patients with gestational diabetes mellitus associated fetal macrosomia.

Fetal macrosomia is commonly associated with gestational diabetes mellitus (GDM) which may lead to various complications. It has been suggested that some other metabolites apart from maternal hyperglycemia are responsible for the genesis of macrosomia. Lipid metabolism changes in GDM patients having macrosomic fetuses were studied. A lipid tolerance test (10% Lipovenous solution) was performed in 14 GDM. Pre- and post-infusion plasma lipid levels and their elimination rates were measured and compared to the ones of 8 non diabetic control pregnant women. HbA1c, basal glucose and triglyceride levels were found to be higher in GDM group and significantly higher levels of triglycerides persisted throughout the infusion. FFA, glycerol and phospholipid levels increased following infusion in both groups without significant differences. Glucose, C-peptide and insulin levels remained unchanged after the infusion. Increased basal triglycerides with slowed triglyceride metabolism may be responsible for the fetal macrosomia in mild GDM patients whose fasting blood glucose are below 105 mg/dl. A better metabolic control that provides plasma lipid regulation as well as glucose control may forestall the occurrence of fetal macrosomia.

Adult↗
PubMed1996

Brain perfusion imaging during preoperative temporary balloon occlusion of the internal carotid artery.

UNLABELLED: The main objective of this study was to assess whether 99mTc-HMPAO brain SPECT imaging can identify patients at high risk of developing an infarct following permanent carotid occlusion in the course of brain surgery. METHODS: Test balloon occlusion of the internal carotid artery was performed in 44 patients with a variety of head and neck tumors or aneurysms. Technetium-99m-HMPAO was injected intravenously while the balloon was initiated and a SPECT study was obtained 30 min later. Follow-up CT scans were obtained routinely for all patients at 2 wk and 1 mo following surgery, or earlier when necessary. Thirty patients and five normal volunteers had semiquantitative analysis of cerebral perfusion. RESULTS: Twenty-six patients demonstrated ipsilateral perfusion abnormalities during trial occlusion. Eight patients in this group underwent bypass grafting prior to sacrifice of the artery: two resulting in infarcts. Eighteen patients had symmetric cerebral perfusion during occlusion and four of these patients underwent permanent therapeutic carotid occlusion; three patients had subsequent infarcts and the fourth patient had an impending stroke. CONCLUSION: Patients with symmetric cerebral perfusion measured by 99mTc-HMPAO SPECT may still have a high long-term complication rate following carotid sacrifice. The scan findings in these patients were not predictive of the outcome. Patients with asymmetric cerebral perfusion had alternative therapeutic approach to carotid sacrifice and most of them had good surgical outcomes.

Brain↗
PubMed1996

Preoperative facial nerve studies predict paresis following cerebellopontine angle surgery.

Facial paresis or paralysis following resection of cerebellopontine angle tumors can occur despite intraoperative cranial nerve monitoring. In an attempt to identify preoperatively those patients at greatest risk for postoperative facial nerve dysfunction, we have prospectively evaluated 30 patients with clinically normal facial function using preoperative facial nerve conduction, electromyography, and the blink reflex. Surgical approach, tumor size, tumor histology, and postoperative facial nerve function were correlated with the preoperative electrophysiologic data to determine the utility of preoperative facial nerve tests as predictors of postoperative facial nerve function. Nineteen patients (Group 1) had normal preoperative facial nerve studies, while 11 patients (Group 2) had abnormal results. Fourteen patients in Group 1 were Grade I immediately after surgery, and five were Grade II. All 19 patients were Grade 1 at 6 months. The 11 patients in Group 2 had immediate postoperative facial nerve function graded as follows: I, three patients; II, five patients; III, one patient; VI, two patients. After 6 months, facial nerve function was graded as follows: I, six patients; II, two patients; III, one patient; VI, two patients. The blink reflex was the single most accurate predictor of facial nerve involvement preoperatively.

Adult↗
PubMed1995

Antenatal diagnosis of lethal osteopetrosis.

We describe a case of the lethal form of osteopetrosis diagnosed prenatally by ultrasonography. Anomalies detected on ultrasound examination at 18 weeks' gestation included skeletal hyperdensity, communicating hydrocephalus and short long bones. At 21 weeks' gestation, cordocentesis was performed to measure the levels of calcium, phosphorus and alkaline phosphatase. The fetus was aborted at 22 weeks' gestation. The diagnosis of osteopetrosis was confirmed by postmortem radiological and histopathological analysis.

Abortion, Induced↗
PubMed1995

Predictive value of balloon test occlusion of the internal carotid artery.

Balloon test occlusion (BTO) of the internal carotid artery (ICA) is used in conjunction with single-photon emission computed tomography (SPECT) imaging to assess the cerebrovascular collateral reserve prior to surgical manipulation of the artery. The present report reviews 56 consecutive patients with tumors or vascular lesions at the base of the skull who underwent BTO and subsequent treatment on that basis within a 3-year period. Four patients underwent carotid sacrifice, since they tolerated the BTO and had normal SPECT imaging. Postoperatively, one patient had patchy infarcts in the frontal lobe, another a middle cerebral artery territory infarction, a third had a lacunar infarct, and the fourth had an impending stroke and was treated with an emergent revascularization procedure. There were 15 patients who underwent saphenous vein bypass grafting, of these there were three graft occlusions, one of which resulted in an infarction. There were two other infarctions due to technical difficulties, one being related to the revascularization procedure. Based on these results, we suggest that passing BTO with a normal SPECT study does not necessarily indicate that the patient is immune to stroke following carotid sacrifice. Revascularization should be considered, when ICA sacrifice is deemed necessary to treat the pathologic condition adequately, to minimize the likelihood of a stroke.

Journal Article↗
PubMed1995

Management of the vertebral artery in excision of extradural tumors of the cervical spine.

Extradural tumors of the cervical spine may involve the vertebral artery on one or both sides, posing one of the limiting factors toward the radical resection of such neoplasms. A standard anterior approach may be inadequate for the management of such tumors. An anterolateral approach allows the dissection and mobilization of the vessel, which can then be preserved, resected, or reconstructed with a vein graft. An anterior approach can be supplemented with this for tumor resection and stabilization. This management strategy is described in 10 patients with a variety of tumors.

Adolescent↗
PubMed1995

Chordomas and chondrosarcomas of the cranial base: results and follow-up of 60 patients.

The management of chordomas and chondrosarcomas involving the cranial base remains controversial. The options for therapy include biopsy, partial resection, radical resection, and various forms of radiotherapy. In this article, we analyze the outcome of 60 patients with cranial base chordoma or chondrosarcoma treated with extensive surgical resection between 1984 and 1993. Forty-six patients had chordomas, and 14 had low-grade chondrosarcomas; 50% of these patients had been treated previously. Preoperative studies included computed tomography, magnetic resonance imaging, cerebral angiography, and balloon occlusion test of the internal carotid artery, as indicated. Magnetic resonance imaging was performed on all patients during follow-up. The surgical approaches used for tumor resection were predominantly the following: subtemporal, transzygomatic, transcavernous, and transpetrous apex; subtemporal and infratemporal; extended frontal; and extreme lateral transcondylar. Staged operations with a combination of approaches were used when necessary (52% of cases) to remove a tumor more completely. Statistical analysis was done by the chi 2 test and correlation matrix. Sixty-seven percent of the patients had total or near-total resection. Twenty percent of the patients received postoperative radiotherapy. Eleven patients died during the postoperative follow-up period, nine with chordomas and two with chondrosarcomas. Three patients died because of systemic complications within 3 months after surgery, five died because of tumor recurrence, one died from unrelated causes, and two died from late complications of radiotherapy. The recurrence-free survival rate for all tumors was 80% at 3 years and 76% at 5 years. Chondrosarcomas had a better prognosis than chordomas (recurrence-free survival rates, 90% at 5 years and 65% at 5 years, respectively; P = 0.09). Patients who had undergone previous surgery had a greater risk of recurrence (5-year recurrence-free survival rate, 64%) than did patients who had not undergone previous surgery (5-year recurrence-free survival rate, 93%; P < 0.05). Patients with total or near-total resection had a better 5-year recurrence-free survival rate (84%) than did patients with partial or subtotal resection (64%) (P < 0.05). Postoperative leakage of cerebrospinal fluid was the most frequent complication (30% of patients) and was found to increase the risk of permanent disability. Patients who had undergone previous radiotherapy had a greater risk of death in the postoperative period (within 3 months of their operations) and during follow-up. However, total or near-total resection did not increase the rate of postoperative disability.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1995

Avid uptake of technetium-99m-HMPAO by an intracranial plasmacytoma during carotid balloon test occlusion.

A 56-yr-old woman was evaluated for removal of a tumor at the base of the skull. A test to determine the risk of carotid artery sacrifice was performed prior to surgery using carotid balloon occlusion of the left internal carotid artery and 99mTc-HMPAO perfusion scintigraphy during the occlusion. An unusual intense focus of increased uptake was seen at the site of the primary tumor in the left cavernous sinus. The tumor, found to be plasmacytoma at surgery, demonstrated only mild washout from 30 min to 2 hr after administration of 99mTc-HMPAO, with a tumor-to-cerebellum ratio of 1.6 and 1.5, respectively, and a tumor-to-contralateral cranial ratio of 2.5 and 2.4, respectively. Intracranial plasmacytoma shows good response to radiation therapy, and the differentiation of this tumor from other neoplasms is pertinent to the mode of treatment and surgical approach. Technetium-99m-HMPAO SPECT imaging may be a useful tool in distinguishing these tumors from other neoplasms at the base of the skull.

Brain Neoplasms↗
PubMed1995

Cranial neuropathy secondary to perineural spread of cutaneous malignancies.

Skin cancers of the head and neck are common lesions that rarely metastasize or invade cranial nerves. Perineural spread, when present, typically involves cranial nerves V and VII, because of their extensive subcutaneous distributions. Partial or complete facial palsy, facial hypesthesia, and/or pain may occur months to years after excision of a cutaneous malignancy and is often the first manifestation of regional metastasis. Too often, a history of facial skin cancer is not elicited in the evaluation of patients who present with fifth and/or seventh cranial nerve neuropathies. The initial yield from computerized tomography and magnetic resonance imaging is often limited, leaving most patients with the diagnosis of Bell's palsy. The authors herein present their experience with the diagnosis and management of seven patients who developed a fifth or seventh cranial nerve neuropathy an average of 13.4 months following "complete" excision of a regional skin cancer.

Aged↗
PubMed1995

Is carotid artery reconstruction mandatory?

The risks and benefits of carotid artery sacrifice should be carefully weighed in every patient individually. The balloon test occlusion with CBF measurement is an important part of the decision process and can guide the surgeon regarding the treatment options most suitable in a particular situation. Although a patient may tolerate temporary occlusion with no CBF disturbance, there is a small risk of stroke on carotid sacrifice. Once the patient suffers a stroke, there is little that can be done. Therefore, if carotid sacrifice is deemed necessary in a patient, some type of revascularization should be considered. Revascularization should be performed with meticulous attention to detail, because it is not without risk. Intraoperative neurophysiologic monitoring and intraoperative arteriography are important adjuncts in such operations.

Adolescent↗