✓ Giant-cell tumor rarely affects the sphenoid bone. Ten cases of this tumor seen at the Mayo Clinic are reviewed, bringing the number of cases in the world literature to 31. These tumors, which present in the second and third decades of life and are slightly more frequent in women than in men, may present with various symptoms, including headache, visual field defects, blindness, and diplopia. The symptom complex and roentgenographic findings are seldom, if ever, sufficiently characteristic to allow preoperative diagnosis. The microscopic differential diagnosis of giant-cell tumor of the sphenoid region includes giant-cell reparative granuloma, aneurysmal bone cyst, fibrous dysplasia, and “brown tumor” of hyperparathyroidism. Interesting features of this series include the presence of multifocal giant-cell tumor in one case, and the absence of Paget's disease of bone in every case. Complete follow-up review in these cases allowed a discussion of therapy and prognosis; it appears that subtotal excision with postoperative radiation therapy is the treatment of choice. While the histological appearance of giant-cell tumor is characteristic, caution must be exercised in interpreting small samples, and various reparative and metabolic disorders must be considered in the differential diagnosis.
Review of 10 cases
James T. Wolfe III, Bernd W. Scheithauer and David C. Dahlin
Case report and review of the literature
James C. Robinson, Scott E. Kilpatrick and David L. Kelly Jr.
✓ The authors report a case of glomus tumor originating within the lumbar spine. Glomus tumors of intraosseous origin are rare, with the only case reported in the spine arising in the sacrum. The patient presented with the solitary complaint of radiating back pain that resolved postoperatively. The histopathological and radiographic findings are reviewed. To the authors' knowledge, this represents the first case report of a glomus tumor of the spine originating above the sacrum.
David F. James and Spencer Braden
Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2005
Jeremy C. Wang, David Spenciner and James C. Robinson
The authors studied the biomechanical properties of a novel spinous process stabilization plate (CD HORIZON SPIRE Spinal System) and present the results in comparison with those of other posterior fixation methods.
Ten functional cadaveric lumbar segments were subjected to nondestructive quasistatic loading forces in 10 different conditions: intact, destabilized (discectomy), fitted with spinous process plate (SPP) alone, with anterior-column support (ACS) alone, ACS with SPP, ACS with posterior translaminar facet screw (PTFS) fixation, ACS with unilateral pedicle screw and rod (UPSR) fixation, ACS with bilateral pedicle screw and rod (BPSR) fixation, UPSR alone, or BPSR alone. Stiffness and range of motion (ROM) data were compared using a repeated-measures, one-way analysis of variance.
The construct with greatest mean limitation of flexion–extension ROM was ACS/SPP at 4.14° whereas it was 5.75° for ACS/UPSR fixation, 5.03° for ACS/BPSR fixation, and 10.13° for the intact spine. The SPIRE plate alone also provided greater flexion and extension stiffness, with less ROM than other posterior stabilization options. Fixation with BPSR with or without ACS resulted in the stiffest construct in lateral bending and axial rotation. The SPP and UPSR fixation groups were equivalent in resisting lateral bending and axial rotation forces with or without ACS.
The SPIRE plate effectively stabilized the spine, and the test results compare favorably with other fixation techniques that are more time consuming to perform and have greater inherent risks.
John D. Pickard, Margaret Matheson, James Patterson and David Wyper
✓ The response of cerebral blood flow (CBF) to drug-induced hypotension was measured in 20 patients who underwent craniotomy for clipping of a cerebral aneurysm following subarachnoid hemorrhage. A modified intravenous xenon-133 injection technique was used to monitor CBF. In 15 patients, CBF increased significantly with hypotension, and only one developed a late neurological deficit. In five patients, CBF fell with halothane-induced hypotension, and four developed delayed neurological deficits. Measurement of the intraoperative CBF response to halothane-induced hypotension may reveal those patients at greatest risk of developing late neurological deficits and who require more intensive postoperative monitoring and early use of the induced hypertension technique.
Report of two cases with autopsy correlation
Andrew J. Molyneux, David W. Ellison, James Morris and James V. Byrne
✓ The authors report the pathological and histological findings in two patients with giant partially thrombosed aneurysms who were treated by means of Guglielmi detachable coils with subtotal occlusion of the aneurysms. Autopsies of these patients were performed 2 and 6 months after endovascular treatment. The histological findings revealed coils embedded in largely unorganized thrombus in the aneurysms; there was no clear reduction in size of the aneurysms over the period. There was no evidence of endothelialization of the aneurysm neck demonstrated in either case. The significance of these findings is discussed.
Joseph Petronio, Ju He, Daniel Fults, Carolyn Pedone, C. David James and James R. Allen
✓ Alterations in P16ink4 or in the gene encoding one of its ligands, cyclin-dependent kinase 4 (CDK4), have been reported in human glioma cell lines and primary tumors but not in primitive neuroectodermal tumors (PNETs), the most common malignant brain tumor of childhood. In this study the authors have examined DNA from 20 primary PNETs in children and from 20 malignant astrocytomas to assess the frequency of P16ink4 and CDK4 gene alterations associated with each type of tumor. Southern hybridization analysis revealed homozygous P16ink4 deletions in one (5%) of 20 PNETs and in seven (35%) of 20 malignant astrocytomas. The CDK4 gene amplification was evident in two additional astrocytomas, but not in any of the PNETs. In total, nine astrocytomas (45%) exhibited homozygous P16ink4 deletion or CDK4 gene amplification, but only one PNET (5%) demonstrated either gene alteration. These results indicate that the incidence of P16ink4 and CDK4 gene alterations in these two groups of tumors is different and suggest distinct pathogenetic etiologies may be associated with each neoplasm.
James T. Rutka
Neil L. Dorward, Olaf Alberti, James D. Palmer, Neil D. Kitchen and David G. T. Thomas
✓ The authors present the results of accuracy measurements, obtained in both laboratory phantom studies and an in vivo assessment, for a technique of frameless stereotaxy. An instrument holder was developed to facilitate stereotactic guidance and enable introduction of frameless methods to traditional frame-based procedures. The accuracy of frameless stereotaxy was assessed for images acquired using 0.5-tesla or 1.5-tesla magnetic resonance (MR) imaging or 2-mm axial, 3-mm axial, or 3-mm helical computerized tomography (CT) scanning. A clinical series is reported in which biopsy samples were obtained using a frameless stereotactic procedure, and the accuracy of these procedures was assessed using postoperative MR images and image fusion.
The overall mean error of phantom frameless stereotaxy was found to be 1.3 mm (standard deviation [SD] 0.6 mm). The mean error for CT-directed frameless stereotaxy was 1.1 mm (SD 0.5 mm) and that for MR image—directed procedures was 1.4 mm (SD 0.7 mm). The CT-guided frameless stereotaxy was significantly more accurate than MR image—directed stereotaxy (p = 0.0001). In addition, 2-mm axial CT-guided stereotaxy was significantly more accurate than 3-mm axial CT-guided stereotaxy (p = 0.025). In the clinical series of 21 frameless stereotactically obtained biopsies, all specimens yielded the appropriate diagnosis and no complications ensued. Early postoperative MR images were obtained in 16 of these cases and displacement of the biopsy site from the intraoperative target was determined by fusion of pre- and postoperative image data sets. The mean in vivo linear error of frameless stereotactic biopsy sampling was 2.3 mm (SD 1.9 mm). The mean in vivo Euclidean error was 4.8 mm (SD 2 mm). The implications of these accuracy measurements and of error in stereotaxy are discussed.
Case report and review of the literature
Alister J. Hart, James Allibone, Adrian T. H. Casey and David G. T. Thomas
✓ Meningiomas, thought to arise from arachnoid cap cells, are usually attached to the dura. Malignancy is present in approximately 1% of these tumors. The authors report the case of a patient with a malignant meningioma arising from the oculomotor nerve with no dural attachment. The patient presented with a 7-month history of left-sided ptosis and diplopia. Magnetic resonance imaging demonstrated an extrinsic mass compressing the root of the oculomotor nerve at its exit from the midbrain. During surgery, a left-sided subtemporal approach revealed the tumor to be arising from the oculomotor nerve. Histological investigation showed a malignant spindle cell lesion with an immunohistochemical profile that was consistent with malignant meningioma. To the authors' knowledge, this is the first documented case of a malignant meningioma arising from the oculomotor nerve.