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Jean-Pierre Farmer, Jack P. Antel, Mark Freedman, Neil R. Cashman, Harold Rode and Jean-Guy Villemure

✓ To analyze the phenotypic profile of lymphoid cells freshly isolated from surgically resected human gliomas, a double-immunostaining technique was developed which permitted the investigators simultaneously to distinguish between hematogenous and tumor cell populations and to detect expression of lymphocyte-mono-cyte subset-specific antigens on hematogenous cells. With this technique, the profiles of tumor-infiltrating lymphocytes (TIL's) derived from high- and low-grade gliomas were compared with phenotypes of lymphocytes concurrently isolated from peripheral blood. The total leukocyte cell yield from high-grade glioma cases exceeded that of low-grade cases. In nine high-grade glioma cases the proportion of CD8-positive cells was increased within the TIL population (41.2% ± 1.9%, mean ± standard error of the mean) as compared to the corresponding peripheral blood lymphocyte (PBL) population (30.8% ± 4.1%, p < 0.05). The proportion of natural killer HNK-positive cells, some of which bear the CD8 antigen (although not necessarily the pan T cell antigens CD2 and CD3), was also increased in the TIL's (41.9% ± 4.2%) compared to that found in PBL's (32.1 ± 5.6%, p < 0.05) of high-grade glioma cases. The observed phenotypic pattern of high-grade glioma TIL's is similar to that reported based on immunohistochemical analysis of tumor tissue sections, suggesting that the techniques described here resulted in isolation of lymphoid cells representative of TIL's.

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Fred J. Epstein, Jean-Pierre Farmer and Steven J. Schneider

✓ The echographic characteristics of 186 suspected intramedullary spinal cord tumors were reviewed. Ultrasonography was found to be specific in distinguishing the tumor type, the extent of the lesion, and the presence and type of associated cysts. Ultrasonography greatly facilitates the selection of respective sites for the placement of a myelotomy, and for initiation of the resection. Additionally, this indispensable adjunct provides ongoing images that allow the preoperative plan to be precisely followed in a surgical field where anatomical landmarks are limited and the margin for error is minimal.

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Fred J. Epstein, Jean-Pierre Farmer and Diana Freed

✓ In this series, 25 adult patients with intramedullary astrocytomas were treated by radical excision alone. Six patients proved to have anaplastic astrocytoma; five of them died within approximately 2 years and the sixth has demonstrated disease progression. The other 19 patients were diagnosed as having low-grade astrocytoma (16 cases) or ganglioglioma (three cases); two of these had advanced preoperative neurological disability and died of medical complications. Fifteen of the remaining 17 patients have no clinical evidence of tumor recurrence after a mean follow-up period of 50.2 months; the other two have a small residual neoplasm that demonstrates no progression. Of these 17 patients, seven had previously received radiation therapy, but had clear evidence of tumor growth subsequently.

This experience suggests that surgery is not beneficial for anaplastic spinal astrocytoma. However, in cases of low-grade tumor, radical excision is associated with minimal morbidity and an excellent long-term prognosis when carried out before significant disability occurs.

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Fred J. Epstein and Jean-Pierre Farmer

✓ During the last decade, several authors have reported that certain brain-stem gliomas may be associated with a better prognosis than others. In this paper, retrospective correlations between the pathological findings and the magnetic resonance (MR) imaging appearance of 88 brain-stem gliomas are established. The authors propose an anatomical hypothesis that helps identify glioma growth patterns in general and that clarifies why cervicomedullary, dorsally exophytic, and focal tumors have a more favorable prognosis. According to this hypothesis, growth of benign gliomas of the brain stem is guided by secondary structures such as the pia, fiber tracts, and the ependyma, which in turn leads to stereotypical growth patterns that are clearly identified on MR images. The authors believe that this hypothesis, in conjunction with clinical data, may help establish selection criteria for the surgical treatment of specific brain-stem lesions.

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Fred J. Epstein, Jean-Pierre Farmer and Diana Freed

✓ Thirty-eight patients underwent surgery for an intramedullary spinal cord ependymoma. In 37 patients, postoperative magnetic resonance imaging confirmed that the tumor was totally removed. The morbidity of surgery was directly related to the preoperative neurological condition. Patients who were normal or nearly normal preoperatively were rarely worse after surgery, and those who had significant disability preoperatively were at greatest risk of being more impaired after surgery. There has been no tumor recurrence in any patient after a mean follow-up period of 24 months, and radiation therapy has not been employed as a surgical adjunct.

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Gordon H. Baltuch, Jean-Pierre Farmer, Kathleen Meagher-Villemure, Augustin M. O'Gorman and José L. Montes

✓ The authors present the case of a 10-year-old boy admitted for evaluation of a generalized seizure and a history of headaches. Computerized tomography (CT) and gadolinium-enhanced magnetic resonance (MR) imaging demonstrated a large nonhomogeneous contrast-enhancing mass of the left frontal lobe, with a large cystic component. Cerebral angiography revealed the lesion to be highly vascular and fed entirely by the internal carotid artery system. The patient underwent craniotomy and the lesion was completely removed. Neuropathological study revealed that the tumor was a ganglioglioma. On review of the literature, it was found that gangliogliomas often present in the second and third decade, are known to have cystic components, and are contrast-enhancing on CT and MR imaging; however, they are classically known to be avascular on angiography. This case of a markedly vascular ganglioglioma emphasizes that these tumors should be included in the differential diagnosis of vascular supratentorial lesions.

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José L. Montes, David B. Clarke and Jean-Pierre Farmer

✓ The authors describe a technique of stereotactic transtentorial hiatus ventriculoperitoneal shunting for the treatment of the sequestered fourth ventricle, used successfully in the care of four patients. They recommend it as a safe, effective treatment of patients suffering from an isolated fourth ventricle.

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Michael Vassilyadi, Jean-Pierre Farmer and José L. Montes

✓ Two cases of children with closed myelodysplasia, Arnold-Chiari malformation, and shunted hydrocephalus who underwent spinal arachnoid cystopleural shunting are presented. Postoperatively, both patients developed craniovertebral symptomatology accompanied by radiologically documented ventricular dilation in spite of negative intracranial pressure and functional ventriculoperitoneal (VP) shunts. Both patients recovered after the cystopleural shunts were revised to increase the resistance to flow within the system. The authors believe that some communication between the arachnoid cyst and the subarachnoid space existed in both cases and that the negative pleural pressure was transmitted preferentially to the spinal and cerebral convexity subarachnoid spaces with relative sparing of the ventricular system. A transmantle pressure gradient was thereby established, leading to ventricular dilation. The authors further suggest that a craniospinal gradient was possibly established as well, leading to craniovertebral symptomatology in the patients. Return of flow in the VP shunts was obtained by correcting this iatrogenic transmantle pressure gradient.

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Olivier Vernet, Jean-Pierre Farmer and José L. Montes

✓ Case records from the Montreal Children's Hospital containing the diagnosis of shunted syringomyelia were retrospectively reviewed. From 1984 to 1994, 31 patients had their syrinx treated by either syringopleural (19 cases, Group A) or syringosubarachnoid (13 cases, Group B) shunting. One patient was included in both groups.

Associated diagnoses included: in Group A, two cases of Chiari I and 14 of Chiari II malformations, 14 cases of shunted hydrocephalus, 13 cases of spina bifida aperta, and three cases of spina bifida occulta; Group B, four cases of Chiari I and two of Chiari II malformations, four cases of shunted hydrocephalus, two cases of spina bifida aperta, and five cases of spina bifida occulta. Eight Group A and six Group B patients had undergone prior posterior fossa decompression. Motor deficits predominated in both groups and arachnoiditis was a uniform operative finding.

Neurological follow-up examinations showed 11 Group A patients improved and eight stabilized, whereas on magnetic resonance imaging, 12 cavities appeared to have collapsed, five were markedly reduced, and one had increased. One patient underwent reoperation for pleural effusions and one for shunt displacement. In Group B, one patient improved, eight stabilized, three worsened neurologically, and one was lost to follow-up review. Radiologically, one cavity appeared to have collapsed, six were significantly reduced, two were unchanged, and three had enlarged.

The authors conclude that syringopleural shunting is a valuable option for controlling syringomyelia in patients without Chiari malformation or in patients who have previously undergone a craniovertebral decompression or are otherwise asymptomatic from their Chiari malformation.

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Olivier Vernet, Jean-Pierre Farmer, Anne-Marie Houle and José L. Montes

✓ To determine the usefulness of urodynamic studies in the management of children with a suspected tethered spinal cord, the authors retrospectively reviewed case records of 25 patients evaluated both pre- and postoperatively using this diagnostic adjunct. All patients were also evaluated with magnetic resonance imaging or computerized tomography myelography. Seven patients who presented initially with orthopedic deformity, skin stigmata, and neurological problems underwent primary cord untethering (Group 1). All seven patients were urologically asymptomatic; all but one had normal findings on urodynamic study. Eighteen patients with prior myelomeningocele closure underwent secondary untethering (Group 2). They presented with urological (11 cases), neurological (three cases), or both urological and neurological (four cases) deterioration. All patients underwent surgery via a microsurgical technique. At a mean follow-up time of 2 years, the only Group 1 patient with preoperative abnormal urodynamic findings normalized following untethering, whereas another asymptomatic patient showed worsened results on his postoperative study. In Group 2, all seven patients with preoperative neurological deterioration improved. Ten of the 15 patients who had isolated or associated preoperative clinical urological deterioration improved or stabilized, whereas five displayed continued deterioration in their bladder function. With respect to urodynamic studies, there was a significant increase in total and pressure-specific bladder capacities following untethering. We conclude that urodynamic studies are useful both diagnostically and in follow-up examinations of patients with tethered cord, that disturbances identified by these studies often precede clinical manifestations of deterioration, and that spinal cord untethering favorably influences the urological status in most patients.