摘要:

SEVERAL SURGICAL APPROACHES to the cerebellopontine angle and internal auditory canal have been developed for the removal of acoustic neuromas. The choice of an approach may be influenced by hearing levels and tumor size. We reviewed the records of the primary translabyrinthine removal of 167 large (≥ 4 cm) acoustic neuromas performed between 1982 and 1990. Patients ranged in age from 15 to 83 years, with a mean of 43 years (male, 49%; female, 51%). Total removal was achieved in 95%. The facial nerve was preserved anatomically intact in 91%. At follow-up (mean, 2.1 yr), facial nerve function was acceptable (Grades I-IV) in 75% and good (Grades I-II) in 42%. Vascular complications occurred in 4.8%; however, there were no deaths. A cerebrospinal fluid leak occurred in 9.6% of cases, and meningitis occurred in 8.3%. In patients with large tumors where there is little chance to preserve preoperative hearing, we have successfully used the translabyrinthine approach for total tumor removal. The advantages and disadvantages of both the translabyrinthine and suboccipital approaches are discussed.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

WITH REFERENCE TO vascular malformations, the termcavernoushas architectural as well as histologic connotations. It refers to a compact pattern of growth wherein no intervening brain parenchyma is evident, as well as to the histological nature of the vessels, which are hyaline and collagenous in appearance, lacking the microscopic features of arteries or veins. Historically,cavernous angiomahas been defined as exhibiting both features. Twenty-five patients with neurological symptoms and neuroimaging abnormalities who underwent surgery for cerebral vascular malformations between 1987 and 1990 satisfied the following study criteria: their lesions were angiographically occult and both magnetic resonance imaging (MRI) and histological sections were available for review. The patients' ages ranged from 4 to 49 years (mean, 30 years), the male to female ratio being 1:2. Two thirds of the lesions were supratentorial in location and all were intraparenchymal. All patients had clinical improvement after resection. In 24 of the 25 lesions, the vascular channels were histologically cavernous in nature; one inadequate specimen precluded classification. Three demonstrated a purely compact or cavernous pattern, 20 a mixed cavernous and racemose pattern, and one a purely racemose pattern. The authors conclude that 1) histologically cavernous lesions are the commonest form of occult vascular malformation; 2) a purely compact or cavernous architectural pattern is uncommon, most lesions showing a partially racemose architecture; 3) some histologically cavernous malformations possess a capillary component; 4) clinical growth of cavernous malformations may have its basis in intraluminal thrombosis and subsequent recanalization; 5) the T2-weighted MRI pattern of cavernous malformations varies, the most common being a multifocal hyperintense center surrounded by a hypointense ring; 6) the MRI pattern reflects the histological appearance; 7) since no thrombosed arteriovenous malformations were encountered, such lesions must be rare; 8) in that the pathophysiological hallmark of a cavernous lesion is recurrent thrombosis and hemorrhage, a resolving hematoma cannot always be distinguished from a cavernous lesion; 9) MRI is the examination of choice in evaluating occult vascular malformations; and 10) microsurgical excision is a satisfactory method of treatment. Lastly, in that occult vascular malformations nearly always exhibit cavernous histology, we suggest the termcavernous angiomabe based upon the histological appearance of the vessels and that the somewhat artificial requirement of architectural compactness be abandoned, at least as far as central nervous system lesions are concerned.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

THE PHYSIOLOGICAL AND anatomical aberrations that result in hemorrhage from cerebral arteriovenous malformations (AVMs) remain unclear. In an attempt to clarify which conditions may predispose to hemorrhage, we examined clinical and physiological indices on presentation groups of either hemorrhage or nonhemorrhage in a large cohort of patients (n = 449). Variables examined included AVM size, type of venous drainage, transcranial Doppler (TCD) velocities, feeding mean arterial pressure (FMAP), and draining vein pressure. TCD and pressure data were obtained before any treatment. Age (mean ± standard deviation) at the time of presentation was 33 ± 13 years and did not differ between groups. Patients with small (≤ 2.5 cm) AVMs presented more frequently with hemorrhage (90%) than did patients with medium (> 2.5 and ≤ 5.0 cm; 52%) or large (> 5.0 cm; 50%) AVMs (P= 0.0001). The 48 of 94 AVMs (51%) with deep venous drainage were more likely to have hemorrhage (P= 0.0219) than were those with superficial drainage (24 of 73 [33%]). Deep drainage was a predictor of hemorrhage even in the subgroup of medium and large supratentorial AVMs (P= 0.005). There was no difference in draining vein pressure (n = 18) between groups (21 ± 10 and 19 ± 11 mm Hg, respectively;P= 0.7812). FMAP (n = 52) was higher in the hemorrhage than in the nonhemorrhage group (44 ± 13 versus 34 ± 10 mm Hg;P= 0.0007) but was only weakly related to the size of the lesion (largest dimension) (y= -0.74x + 40;r= 0.09). Unlike FMAP, TCD velocities correlated well with largest dimension (n = 76;y= 15x+ 86;r= 0.55). Although the hemorrhage group demonstrated lower mean flow velocities (94 ± 40 versus 114 ± 33;P= 0.0236), the absolute differences were small, suggesting that TCD indices are more related to size than propensity for hemorrhage. By the use of a multiple logistic regression model, in the subset of patients with medium or large AVMs and superficial venous drainage (the group with the lowest identified risk of intracerebral hemorrhage), FMAP had a strong influence on the incidence of intracerebral hemorrhage, (P= 0.0086), but TCD velocities did not. In summary, smaller nidus size and the presence of deep venous drainage are independent predictive factors that may increase the risk of hemorrhage from AVMs. Finally, higher FMAP is an important factor in the pathophysiology of hemorrhage from AVMs and not just a consequence of lesion size.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

RECENT EXPERIMENTAL AND clinical reports suggest that the intracisternal administration of recombinant tissue plasminogen activator (tPA) within 72 hours of subarachnoid hemorrhage decreases the incidence of severe angiographic and clinical vasospasm. In this report, we present four of eight patients with aneurysmal subarachnoid hemorrhage who developed angiographic and clinical vasospasm with delayed neurological deterioration, despite the use of intracisternal tPA after early aneurysm clipping. One patient did not clear her massive subarachnoid hemorrhage with tPA; one patient had extremely poor collateral flow with occlusion of one cervical internal carotid artery and 80% stenosis of the other cervical internal carotid artery; the other two patients had a subarachnoid hemorrhage 7 to 12 days after their sentinel hemorrhage. Three patients ultimately made excellent or good recoveries, and one was left with hemiparesis. The four other patients treated by this protocol did not develop vasospasm. We conclude that intracisternal tPA may not prevent vasospasm in certain patients. This may relate to inadequate clearing of the subarachnoid clot, pre-existing poor collateral supply, or the occurrence of prior subarachnoid hemorrhage.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

THE AUTHORS STUDIED 65 patients with intractable seizures and glial tumors who were treated between 1978 and 1991. Most of the tumors were in the temporal (63%) or occipital lobe (18%) and were commonly found in limbic or perilimbic neocortical locations. The majority of these gliomas (83%) involved the gray matter of allocortex, neocortex, or transitional cortex. These tumors spanned a wide range of glial differentiation: Most (61%) were low-grade astrocytomas, but 17% were histologically malignant. However, their biological behavior was strikingly indolent, as suggested by a stable clinical history during many years of chronic seizures (mean, 15 yr). The median follow-up time since the onset of symptoms in these patients was 17.2 years, and only one patient in the entire series died from the tumor. The mainstay of the surgical treatment was resection of the gliomas to histologically confirmed, tumor-free margins. The resection was not guided by intraoperative electrocorticography. Of the 60 patients who had a postoperative follow-up of more than 1 year, 82% were seizure free. Of the 31 patients who had auras with their seizures, 87% did not retain their auras postoperatively. Of the patients who were rendered seizure free, only one patient continued to have auras. Failure in seizure control was associated with an incomplete resection of the lesion. In patients with temporal lobe tumors, seizure outcome was not significantly related to the extent of medial temporal resection. It is suggested that limbic and perilimbic gliomas associated with intractable seizures constitute a distinct clinicopathologic group of glial tumors that involve the gray matter, arise in a young host, and exhibit stable biological behavior over many years. Surgical treatment that includes complete resection of these tumors can achieve excellent seizure control.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

WE MEASURED THE level of myelin basic protein (MBP) in the cerebrospinal fluid (CSF) of patients with various kinds of tumors, including malignant tumors, using radioimmunoassay. The CSF had been obtained by lumbar puncture through an Ommaya reservoir or a shunt device placed in the lateral ventricle. The level of MBP was high (> 4 ng/ml) in the patients with meningeal dissemination of malignant tumors, but in those who showed a good response to chemotherapy and/or radiation, it decreased or returned to the normal level, with improvement on the computed tomography and magnetic resonance imaging, cytological, general CSF, and neurological findings. Of seven malignant gliomas without CSF dissemination, six showed an elevated level of MBP before selective intra-arterial chemotherapy with a combination of etoposide and cisplatin administered via a microcatheter placed at A1, M1, P1-P2, and the basilar top. All CSF specimens obtained during the period of the intra-arterial chemotherapy showed an abnormally high (> 4 ng/ml) level of MBP that exceeded the prechemotherapy level. The MBP level decreased or returned to normal in the patients with a good response to chemotherapy after intra-arterial chemotherapy. In some patients with multiple metastatic brain tumors, the MBP level was elevated before treatment and returned to normal after treatment (surgical removal, chemotherapy, and/or irradiation) in all except one. Thus, there was a clear correlation between the timing of treatment and changes in imaging studies and MBP levels. Only 3 of the 18 patients who had received irradiation and demonstrated no brain tumors on magnetic resonance imaging after radiation therapy showed an abnormal MBP level; one developed brain atrophy 1 month after chemotherapy and radiation therapy for multiple metastatic brain tumor, one had massive edema after the macroscopically total removal of a recurrent anaplastic meningioma, and the other had necrotizing encephalopathy, which developed 6 months after the complete disappearance of anaplastic astrocytoma by chemotherapy and radiation therapy. Patients with benign brain tumors generally showed a normal MBP level; only 2 of 22 patients, one with meningioma with very extensive edema and the other with an unstable postoperative condition after the total removal of a large craniopharyngioma, showed a high MBP level. These findings suggest that the MBP level reflects not only brain damage in the acute stage but also the effect of treatment, including surgery, radiation, and/or chemotherapy, in malignant brain tumors.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

PROLACTIN (PRL) LEVELS ARE frequently elevated in patients with non-PRL-secreting adenomas or other intrasellar and parasellar diseases (“pseudoprolactinomas”). This phenomenon is believed to result from a loss of dopaminergic inhibition on pituitary lactotrophs and is known as the “stalk-section effect.” Using magnetic resonance imaging scans and a high-magnification sella technique, we measured a number of parameters indicative of the disruption of normal sellar structures. The investigator was blind to the patient's diagnosis and PRL level while collecting the data. Parameters measured were the tumor size, the angular deviation of the pituitary stalk, and the degree of compression of the pituitary stalk. Measurements were obtained from 44 patients with pathologically confirmed tumors that had no immunohistochemical reactivity to PRL. PRL levels were often higher than expected. Four patients (9%) had a PRL level of more than 150 ng/ml, and three patients (7%) had a PRL level of 200 ng/ml or more. One patient with a plasmacytoma eroding the sella floor had a PRL level as high as 504 ng/ml. There was no significant correlation of PRL level and the degree of pituitary stalk compression, stalk deviation, or tumor size. PRL levels were found to be markedly elevated in some patients with a tumor causing little distortion of the pituitary stalk. Conversely, PRL levels were often normal despite evidence of massive distortion of the stalk. Therefore, magnetic resonance imaging evidence of pituitary stalk distortion cannot be used to determine the diagnosis of prolactinoma versus pseudoprolactinoma in most cases. The lack of correlation of PRL level in patients with nonprolactinomas is important in view of recent doubts concerning the role of the “stalk-section effect.” A number of illustrative cases are presented.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

RELIABLE ASSESSMENT OF the probability that a head injury patient harbors a surgical intracranial lesion is critical to both triage and treatment. The authors analyzed data from 608 patients with severe head injuries (Glasgow Coma Scale score, ≤ 8) in the Traumatic Coma Data Bank to assess the reliability of pupillary asymmetry in predicting the presence and location of an intracranial mass lesion. Of 210 patients with pupillary asymmetry of ≥ 1 mm, 63 (30%) had intracranial mass lesions, 52 (25%) of which were extra-axial in location, 38 (73%) of these located ipsilateral to the larger pupil. Of 51 patients with asymmetry of ≥ 3 mm, 22 (43%) had intracranial mass lesions, 18 (35%) of which were extra-axial in location, 14 (64%) of these located ipsilateral to the larger pupil. For both asymmetry categories, strong interactions were found with age and mechanism of injury, the highest incidence of extra-axial lesions occurring in older patients injured other than as occupants of motor vehicles. The authors developed regression equations that provide a graphic means to predict the presence of an intracranial hematoma using data on pupillary asymmetry, age, and mechanism of injury. This predictive model, interpreted in a hospital- and patient-specific fashion, should be of significant use in directing triage, activating diagnostic and therapeutic resources, and evaluating the utility of exploratory trephination.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

MANY NEUROSURGEONS HAVE made a practice of sectioning the S2 dorsal roots during selective posterior rhizotomy for the treatment of spasticity in children with cerebral palsy, but the efficacy of this treatment has not previously been proven. S2 afferents are involved in reflex arcs of the plantar flexors (PFs), so that S2 lesioning should in theory reduce PF spasticity. To test this assumption, we determined the frequency of postoperative residual spasticity in the PFs when S2 lesioning was or was not performed. We assessed 85 children for whom 6-month follow-up was available. Functional rhizotomy from L2-S1 was performed on 13 of them (26 legs with PF spasticity) and from L2-S2 on 72 (141 legs with PF spasticity). Rootlets were lesioned if there was an abnormal response to intraoperative electrical stimulation. In 20 patients, lesioning of the S2 rootlets was assisted by the “pudendal neurogram,” a technique previously shown to prevent bladder dysfunction during sectioning of the sacral roots. When S2 roots were excluded from the lesioning process, residual PF spasticity was detected in 35% of the legs that had it preoperatively, leaving 5 (38%) of 13 children with functionally impairing spasticity. When S2 roots were included, 6% of legs that had PF spasticity retained it postoperatively (P< 0.001), leaving 8 (11%) of 72 patients with functionally limiting spasticity (P< 0.05). Thus, the addition of the S2 roots to the procedure resulted in an 81% reduction in the number of legs with residual PF spasticity and a 71% reduction in the number of patients with residual PF spasticity. The use of the pudendal neurogram did not alter the incidence of residual spasticity. We conclude that including the S2 roots in selective functional rhizotomy significantly reduces PF spasticity.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

THORACIC OSSIFICATION OF the posterior longitudinal ligament (OPLL) is a rare entity causing thoracic myelopathy. Its surgical decompression is still challenging. Three patients admitted with progressive myelopathy due to thoracic OPLL are described. A transthoracic anterolateral approach was used in the first and second cases, in which OPLL was located at the T3-T4 and T5-T6 and at the T7-T8 levels, respectively. In the third case, a transsternal approach was adopted for OPLL at the T1-T2 level. The OPLL, including dural ossification, was removed by microsurgical techniques as extensively as possible. Myelopathy in all three cases became relieved or stable postoperatively. Operative procedures are described in detail. From the viewpoint of surgical anatomy, the selection of operative approach depends on the level of the OPLL. The authors emphasize that a transthoracic anterolateral approach is the treatment of choice for extensive anterior pathology such as OPLL involving more than two thoracic bodies below the T4. A transsternal approach can provide excellent access to a lesion at the upper three thoracic bodies.

ISSN:0148-396X    

出版商:OVID    

年代:1994

数据来源: OVID