PubMed Health⌕ Search

Biomedical subjects

M G Siqueira

Publications and source records attributed to M G Siqueira.

13 recordsLinked to original sources
PubMed2003

Prognostic factors and treatment of penetrating gunshot wounds to the head.

BACKGROUND: In an attempt to evaluate the predictive factors of morbidity and mortality in patients who suffered from civilian gunshot wounds to the head, we reviewed a series of 319 patients admitted to the Hospital Santa Marcelina, São Paulo, Brazil, between 1994 and 2000. METHODS: Clinical and cranial computed tomography (CT) results are described. The initial Glasgow Coma Scale (GCS), the presence of an unilateral dilated pupil or medium fixed pupils, and five different findings in the CT scan were considered as variables. The Qui-Square Fisher test was utilized to verify the correlation between the presence of the variables and the occurrence of an increased mortality rate and of an unfavorable outcome (Glasgow Outcome Scale = 2 and 3). RESULTS: In 265 cases the missile penetrated the dura (83%). In our study there was a significant correlation between the low GCS scores on admission and a higher mortality (p < 0.001). This kind of correlation was also noted with patients admitted with unilateral dilated pupil and medium fixed pupil. There were 187 patients (70.5%) evaluated by CT scan. There was a significant correlation between the presence of transventricular or bihemispheric central type trajectory and high mortality. The patients admitted with unilobar supratentorial wounds resulted in better outcome when compared to those with bilobar or multilobar wounds (p < 0.001). A group of 156 patients was submitted to an aggressive surgical protocol. The best results were seen in patients admitted with initial GCS score higher than 8. CONCLUSIONS: We conclude that low GCS scores at admission, unilateral dilated pupil or medium fixed pupil, transventricular or bihemispheric central type trajectory, and bilobar or multilobar wounds noted through CT scan are predictive factors of high morbidity and mortality in patients with gunshot wounds to the head, in our clinical experience. We also conclude that surgical treatment is not recommended for patients with penetrating wounds and GCS score of 3 to 5 in the absence of hematoma causing a mass effect.

Adolescent↗
PubMed2001

Naso-ethmoid schwannoma with intracranial extension: case report.

Intranasal schwannomas are rare lesions, specially when they present with an intracranial extension. The fifth case in the medical literature of a naso-ethmoid schwannoma with extension into the anterior cranial fossa is presented. The magnetic resonance findings and the details of the combined intracranial / transfacial operative approach used are described. The possible origin and the clinical characteristics of this rare lesion are reviewed.

Adult↗
PubMed2000

[Intraspinal dermoid tumor associated with diastematomyelia: case report].

Intraspinal dermoid tumor and diastematomyelia is a rare combination of pathologies and only eight cases were priorly published. We report a new case in an adult with clinical presentation of progressive paresis and sensitive deficit in the lower limbs, associated with a thoraco-lombar kyphoscoliosis. The diagnosis based on the CT scan and MR images was confirmed at surgery. Pathophysiologic and clinical aspects as well as the radiological characteristics of these pathologies are dicussed and the importance of the early diagnosis is emphasized.

Adult↗
PubMed1997

Management strategies for posterior cerebral artery aneurysms: a proposed new surgical classification.

In a period of 10 years fifteen patients bearing sixteen aneurysms arising at the posterior cerebral artery were operated at our institution. Based on the approaches selected for each location a division of the posterior cerebral artery into three surgical segments is proposed. The first segment (S1), or anterior extends from the basilar artery bifurcation to the point where the artery reaches the level of the most lateral edge of the cerebral peduncle, the second segment (S2), or middle extends from the posterior limit of S1 to a point located just before the most medial extent of the artery in the quadrigeminal cistern (collicular point), and the third segment (S3), or posterior corresponds to the collicular point and to the portions of the posterior cerebral artery distal to it. Utilizing the concept of surgical segments all aneurysms in our series were satisfactorily exposed. Those arising at the S1 segment (8 cases) were operated either through a pterional or a pretemporal approaches; those from the S2 segment (6 cases) were operated either via the subtemporal or the subtemporal transventricular routes; and that arising from the S3 segment (1 case) was managed through the occipital interhemispheric approach. Among the aneurysms eleven were small, one was large, and four were large or giant. Ten of these aneurysms were surgically clipped, two coagulated, three treated by trapping and in one case the aneurysm was resected and the posterior cerebral artery was reconstructed by a termino-terminal anastomosis. The surgical results were considered good in all cases but one, where the patient died due to clinical complications three months after surgery. It is our belief that the use of this classification can provide the means to best select the most appropriate surgical approach to treat aneurysms arising at the posterior cerebral artery.

Adolescent↗
PubMed1997

Arteriovenous malformations of the basal ganglia region: rationale for surgical management.

Surgical indications for arteriovenous malformations (AVMs) arising at the region of the basal ganglia are questionable and the majority of cases are considered inoperable. Albeit not free from risks of morbidity and mortality, the treatment of choice is usually radiosurgery for small lesions, and embolization plus radiosurgery for larger lesions. Nevertheless, some lesions may be amenable for surgical resection due to their favorable location. Eighteen cases of such AVMs were selected for a direct approach in our series. Seventeen cases were classified as Spetzler and Martin [22] grade III, and one case was a grade V. Ten patients were males and eight females. The mean age was 28.3 years (ranged from 2 to 43 years). Sixteen patients had had previous hemorrhagic events prior to hospital admission. Eleven patients had pre-operative well established neurological deficits, and seven patients although symptomatic had a normal neurological exam at admission. Fifteen patients had their AVMs completely resected. Among the eleven patients with previous neurological deficits nine had no change in their pre-operative condition and two experienced postoperative neurological worsening. In the long-term follow-up six patients had a complete recovery and five recovered only partially. Among the seven patients whose neurological examination was normal pre-operatively five remained unchanged, one had a transient motor deficit, and one died due to a thalamic venous infarction and massive bleeding into the thalamus. The anatomical knowledge and the precise localization of the arteriovenous malformation through the aid of neuroimage studies has provided the means to classify these AVMs and plan operative strategies for some small selected cases with relatively low morbidity.

Adolescent↗
PubMed1997

Indications for, contraindications to, and interruption of craniofacial procedures.

In spite of increasing experience with skull base surgery, some of the guidelines for indications for operations may vary according to the institution. One-hundred two patients underwent craniofacial oncologic resections at our institution from 1982 to 1995. A retrospective analysis of the indications for and contraindications to these procedures was undertaken. The main indications for malignant tumors were skin lesions with direct invasion of the anterior or lateral skull base (69%) and nasal-paranasal sinus tumors (21%). The main indications for benign tumors were glomus lesions (26%), menigiomas (22%), and fibro-osseous lesions of the anterior skull base (19%). The main contraindications were extensive invasion of the central nervous system, invasion of the cavernous sinus and/or internal carotid artery by aggressive malignancies, and bilateral orbital invasion in a nonblind patient. Also, 6 patients had their procedures interrupted during craniotomy for several reasons - extensive central nervous system invasion (2 cases), bilateral orbital invasion (1), lack of brain retraction (1), lack of histologic diagnosis during the operation (1), and purulent discharge at the frontal sinus (1). Craniofacial oncologic operations are extensive surgical procedures that have to be properly indicated in order to obtain low levels of morbidity and mortality. The selection of cases is of paramount importance. In some instances, it seems advisable even to interrupt these operations in the first phase.

Adult↗
PubMed1996

Anatomical and technical aspects of the contralateral approach for multiple aneurysms.

Microsurgery of multiple aneurysms is still a controversial subject. In order to avoid the risk of rebleeding and the consequent increase in morbidity in such cases all aneurysms or at least as many aneurysms as possible should be treated in the first operative procedure. To reach that goal aneurysms located on the contralateral side should also be considered for clipping during the first operation. Between 1984 and 1994 a series of 51 patients harboring multiple aneurysms of which 55 aneurysms were located on the contralateral side of the craniotomy were operated at our institution. No mortality or morbidity could be directly ascribed to the aneurysm that was clipped contralaterally. Based on that series we have described the anatomical features, technical aspects and surgical difficulties of approaching bilateral aneurysms through the same craniotomy.

Aneurysm, Ruptured↗
PubMed1995

The pretemporal approach to the interpeduncular and petroclival regions.

A pretemporal approach to the interpeduncular and petroclival regions is described. Through a frontotemporal craniotomy based very low in the middle fossa the temporal lobe is completely exposed. The Sylvian, carotid, chiasmatic, and lamina terminalis cisterns are widely opened. The arachnoid fibers between the uncus and the frontal lobe, as well as those binding the temporal lobe to the tentorial edge and to the oculomotor nerve are also separated. The bridging veins from the temporal pole to the spheno-parietal sinus are usually coagulated and sacrificed allowing for posterior displacement of the temporal lobe. The approach combines the advantages of both the classical pterional and subtemporal approaches providing unhindered exposure of the anterior portion of the tentorial incisura in dealing with vascular and tumoural lesions arising at the sellar, parasellar, and interpeduncular regions, and at the superior aspect of the petroclival region.

Basilar Artery↗
PubMed1994

Results and prognostic factors in skull base surgery.

The charts of 81 patients who underwent skull base surgery between 1982 and 1993 were reviewed retrospectively. Data relative to demographic aspects, clinical stage, previous treatment, surgical approach, type of reconstruction, histology, extent of disease, complications, and follow-up were analyzed. The craniofacial approach for the anterior fossa was used in 53% of patients, the lateral skull base approach in 12%, and a combination of both in 17. Malignant tumors were diagnosed in 58 patients (72%), and histologically benign tumors in the remaining 23 (28%). Forty-one patients (51%) had skin cancer. There was dural invasion in 31 patients (38%), and 32 (40%) underwent microsurgical flap reconstruction. From the malignant group, 31 (53%) were alive with no evidence of disease (NED), and 6 (10%) were alive with disease. From the benign group, 19 (83%) were alive NED. The most common complications were cerebrospinal-fluid fistula (10%) and flap necrosis (9%). Statistical analyses of survival showed significantly different rates associated with histologic types (P = 0.0002), type of reconstruction (P = 0.0039), and previous treatment (P = 0.0018).

Adolescent↗
PubMed1984

Subclinical pituitary microadenomas.

To analyze the incidence as well as the natural history of asymptomatic pituitary microadenomas, 450 pituitary glands obtained during routine autopsies were studied. The series consisted of patients of both sexes, without any evidence of pituitary dysfunction, in a broad age range. Thirty-nine tumors were found in 36 pituitary glands, with a peak incidence in the seventh decade of life and an evident predominance in male patients. The medical records and available x-ray films of the skull of these patients with subclinical microadenomas were reviewed for clinical evidence of endocrinopathy and to detect minor radiologic abnormalities of the sella turcica. No significant differences were found in comparing the histologic aspect of these tumors with symptomatic cases. The possibility of these tumors as a preclinical stage of pituitary adenoma or a separate entity is discussed.

Adenoma↗
PubMed1980

[Experimental aneurysms: proposal for a new technic].

The authors present a critical analysis of the various methods of experimental production of aneurysms and report their own method in which saccular aneurysms were produced at the bifurcation of the common carotid artery in dogs with vein patch grafts. The objective point of this study was the creation of an experimental model to evaluate the efficacy of a therapeutic procedure. These aneurysms have a low incidence of thrombosis and a tendency to enlarge and to become spherical. They closely simulate the saccular aneurysms developing spontaneously in the cerebral arteries of man, and as such are useful models for experimental purposes.

Animals↗
PubMed1980

[Intracranial saccular aneurysms: experimental evaluation of intravascular therapeutic procedures].

Studies were performed on adult mongrel dogs to evaluate the possibility of occluding saccular aneurysms with an intravascular injection of the tissue adhesive Bucrylat (isobutyl-2-cyanoacrylate). Fourteen surgically constructed carotid aneurysms were occluded by the injection of Bucrylat through a fluoroscopically positioned intra-arterial catheter. Angiography performed immediately before and after injection and up to 1 month following treatment revealed progressive and persistent occlusion of the aneurysms. The specimens examined histologically 1 month after the injection showed an endothelialized fibrous tissue bridge crossing the neck of the aneurysm what appear to indicate a permanent occlusion of the structures treated. A similar approach to treat intracranial aneurysms will depend on advances in the field of selective intracranial catheterization that will permit safe and accurate catheterization of the aneurysm sac.

Animals↗