The value of MRI in the diagnosis of postoperative spondylodiscitis.

We evaluated the role of MRI in the diagnosis of postoperative spondylodiscitis. Spondylodiscitis is a serious complication of surgery, and the diagnosis frequently depends on a combination of clinical, laboratory and imaging findings. We compared the MRI findings in six patients with biopsy- or surgery-proven spondylodiscitis with those in 38 asymptomatic postoperative patients. Contrast enhancement and signal changes in the intervertebral disc or the vertebral endplates are not specific for spondylodiscitis, being also seen in the asymptomatic patients. However, absence of Modic type 1 changes, of contrast enhancement of the disc or of enhancing paravertebral soft tissues suggests that the patient does not have spondylodiscitis. MRI appears more useful for exclusion than for confirmation of postoperative spondylodiscitis.

Molecular pathogenesis of astrocytoma and glioblastoma multiforme.

Our understanding of the complexity of genetic abnormalities involved in the tumourigenesis of malignant gliomas is as yet rudimentary. However, we can discern distinctive patterns of loss of genetic material and amplification of chromosomal regions that characterize both the different types of gliomas as well as the different malignancy grades. In this review, we discuss through specific examples of recent work on astrocytomas and glioblastoma multiforme, the importance of several tumour suppressor genes and oncogenes in the development of these glial tumours. In conclusion it would seem that distinct genetic changes in different genes, the protein products of which interact in particular growth control mechanism may lead to the same cellular abnormality. It seems likely that many further genetic abnormalities affecting genes coding for proteins, either involved in the cellular mechanisms yet identified or in new growth control mechanisms. Will be found in the near future.

MRI after successful lumbar discectomy.

Our aim was to establish the normal range of MRI findings after successful lumbar discectomy. We prospectively examined 34 consecutive patients with an excellent clinical outcome by MRI 6 weeks and 6 months after surgery. All examinations included sagittal and axial spin-echo (SE) T1-weighted images before and after intravenous gadolinium-DTPA and fast SE T2-weighted images. Contrast enhancement along the surgical tract was seen in all patients 6 weeks and 6 months after surgery. After 6 months minimal or no mass effect on the dural sac by epidural scar was seen. In 20% of patients there was recurrent disc herniation, with mass effect. Enhancing nerve roots were seen in 20% of patients 6 weeks postoperatively, and half of these were associated with recurrent disc herniation at the same side. None of these patients still showed nerve root enhancement 6 months after surgery. Postoperative MRI studies must be interpreted with great care since the features described in the failed back surgery syndrome are also found, to some extent, in asymptomatic postoperative patients.

Early postoperative gadolinium-DTPA-enhanced MR imaging after successful lumbar discectomy.

A prospective study was undertaken to establish the normal spectrum of early gadolinium-enhanced magnetic resonance (MR) imaging findings in patients who had resolution of symptoms after lumbar discectomy. Thirty-four patients underwent MR examinations 6 weeks and 6 months after lumbar discectomy on a 1.5 T superconducting unit, including sagittal and axial spin-echo (SE) T1-weighted images before and after intravenous administration of gadolinium-DTPA, as well as sagittal turbo (or fast-) SE T2-weighted images. All patients showed soft tissue enhancement along the surgical track in the subcutaneous soft tissue lateral to the spinous process and in the epidural space. There was only minimal (45%) or no (55%) mass effect on the dural sac associated with epidural scar formation 6 months after surgery, but often the nerve root at the operative level was surrounded by this enhancing tissue. Facet joint enhancement was seen in most patients 6 weeks (63%) and 6 months (53%) after surgery. Intrathecal nerve root enhancement was observed in six patients, 6 weeks after surgery. Nine patients (20%) had residual mass effect on the neural elements with an enhancement pattern suggestive of a disc fragment. Enhancement of the intervertebral space was seen in 67% of patients 6 weeks after surgery and in 86% of patients after 6 months. It may be concluded that, despite the use of gadolinium-DTPA, MR studies obtained in the initial postoperative period are difficult to interpret, because of the normal sequence of changes. Consequently, the clinical picture still remains the major indicator for recurrent surgery.

Diagnostic imaging algorithm for cervical soft disc herniation.

MR imaging with surface coils is currently the preferred method for the evaluation of cervical soft disc herniation. However, the differentiation between soft disc herniation and osteophytic spurs in the neural foraminal canal is not always obvious on a 0.5 Tesla unit. Therefore the specificity for neural foraminal canal pathology has been reported not to be very high. We evaluated MRI in selected patients without major foraminal spurs or important spondylosis on plain radiography. This prospective study includes 100 patients with cervical radicular symptoms, not subsiding after conservative treatment. All patients underwent plain radiograms. Patients without spinal instability, spondylosis or major osteophytes on plain radiograms and without clinical findings of myelopathy underwent MRI (n = 59) on a 0.5 Tesla superconducting system. All 41 other patients underwent CT myelography. On MRI, a cervical soft disc herniation was observed in 55 out of 59 investigated patients and the localization corresponded well with the clinical symptoms. CT myelography demonstrated a foraminal herniation in 1 of 4 selected patients with negative MRI. Fifty out of 55 patients underwent anterior cervical discectomy without fusion. All herniations were confirmed at operation, but in two patients there were important foraminal spurs, not seen on MRI. The specificity of MRI in this study is 94%. It is concluded that 0.5 T MRI, combined with plain films offers an accurate, noninvasive test in the assessment of selected patients with cervical radiculopathy.

Instability of microsatellites in human gliomas.

We have analyzed DNA obtained from 10 glioblastomas multiforme and 6 astrocytomas for microsatellite instability, using 17 different microsatellite loci dispersed over 7 different chromosomes. Six of 16 gliomas showed 1 or more microsatellite alterations in tumor DNA as compared to constitutional DNA. We observed microsatellite instability resulting in allelic shifts in 5 of 10 glioblastomas multiforme but not in any of the astrocytomas. Loss of an allele was observed in 3 glioblastomas multiforme. An imbalance in the intensity of alleles was noticed in 1 astrocytoma and in 1 glioblastoma multiforme. In 1 glioblastoma multiforme, an extra allele was present at two distinct loci. Overall, 5.3% of microsatellite analyses showed an abnormality. We conclude that microsatellite instability is present at a low grade in glioblastomas multiforme but to a lesser extent in astrocytomas. Genomic instability in human gliomas, therefore, should not be regarded as a mechanism for tumor initiation but as an evolution in tumor progression.

Early restructuration of consciousness after traumatic coma.

Recovery of consciousness after acute brain injury is a remarkable phenomenon, yet, not completely understood. We describe the early clinical stages of recovery of consciousness in 48 selected patients by means of different items of the Glasgow Coma and Liege Coma Scales. Arousal, expressed by the stimulated opening of the eyes (E2) was correlated with the appearance of the localizing pain response (M5), with the capacity to obey commands (M6), with the opening of the eyes (E4) and with the blink reflex (R5). This study confirms the classical clinical sequence of arousal and recovery of consciousness characterized by the consecutive appearance of E2, R5, E4, M5 and M6. When the appearance of E2 and R5 are considered separately, we noticed a significant difference, suggesting different structural and functional brain recovery processes.

Instability of short tandem repeats (microsatellites) in human gliomas.

OBJECTIVE: Microsatellite instability implying multiple replication errors (RER) characterizes a proportion of familial and sporadic carcinomas. The purpose of this report is to analyze whether microsatellite instability occurred during the development of human gliomas. EXPERIMENTAL DESIGN: We checked prospectively 16 central nervous system tumors, including 10 glioblastomas and 6 astrocytomas of different malignancy grades, for genetic microsatellite instability. Fifteen different microsatellites, located on 6 different chromosomes, were investigated. All microsatellites are dinucleotide CA, repeats except for D11S956,P23 (CTAT) and CYP 19, which are tetranucleotide repeats and P23 (GTTTT) which is a pentanucleotide repeat. The repeats were analysed by PCR amplification, followed by electrophoresis on denaturing 6% polyacrylamide gels. MEASURES: We looked for all kinds of microsatellite alterations. Only microsatellite shifts were considered to represent microsatellite instability. RESULTS: Three out of 10 glioblastomas showed mobility shifts on gel electrophoresis in tumor, compared to corresponding normal DNA samples. In contrast, no microsatellite instability was found in any of the astrocytomas. Besides the presence of larger or smaller alleles, an imbalance in the ratio between alleles was noticed in one astrocytoma and in one glioblastoma multiforme. In addition, loss of heterozygosity (LOH) is observed without a fixed pattern in 3 glioblastomas. CONCLUSIONS: We conclude that genetic instability of microsatellites may be demonstrated in high grade gliomas rather than in their low grade precursors and should be regarded as an evolution in tumor progression rather than as a new mechanism for tumor initiation in gliomas.

Clinical recovery of consciousness after traumatic coma.

OBJECTIVE: To describe early clinical stages in the recovery of consciousness, using selected items from the Glasgow Coma Scale and the Liège Coma Scale. DESIGN: Validation cohort study, conducted in a tertiary care center. SETTING: Neurosurgical intensive therapy unit in a university teaching hospital. PATIENTS: Patients (n = 137) with traumatic coma who were selected according to the following criteria: a) coma due to blunt head trauma with an initial Glasgow Coma Score of < or = 7; b) admission to the neurosurgical intensive therapy unit within the first 24 hrs after trauma; c) patients > 14 yrs of age; requiring endotracheal intubation, mechanical ventilation, and the administration of drugs; and d) survival period allowing analysis of the recovery of consciousness. MEASUREMENTS AND MAIN RESULTS: Arousal, as expressed by stimulated opening of the eyes and recorded as a delay in days, was correlated with the appearance of the localized pain response, capacity to obey commands, blink reflex, and the cessation of drugs in three groups of patients. These groups were defined according to the time in which there was an appearance of the stimulated opening of the eyes: < 8 days (group 1); between 8 and 15 days (group 2); and after 15 days (group 3). When the three groups of patients were compared, significant differences existed between the mean delays of appearance of stimulated eye opening and the appearance of the blink reflex. Extubation coincided with the appearance of spontaneous eye opening, with a mean delay of 13.5 days. CONCLUSIONS: This study confirms the classical clinical sequence of arousal and recovery of consciousness, with the appearance of stimulated eye opening and the blink reflex first, followed by spontaneous eye opening, and the capacity to obey commands in intubated, traumatized, coma patients. A direct correlation existed between the delay of arousal and the complete recovery of consciousness. When groups of patients with various mean delays for the appearance of stimulated eye opening are considered, reappearance of the blink reflex did not always coincide with stimulated eye opening, suggesting differing structural and functional brain recovery processes.

Diagnostic imaging algorithm for cervical soft disc herniation.

MRI with surface coils is currently the preferred method for evaluating degenerative cervical spine disease. The differentiation between soft disc herniation and osteophytic spurs is not always obvious, however, on a 0.5 Tesla unit. The procedure of choice for soft disc herniation, MRI on a 0.5 T superconducting system associated with plain radiography of the cervical spine, in selecting patients for anterior cervical discectomy without interbody fusion (ACD), was evaluated. This prospective study comprised 100 patients with cervical radicular symptoms, not subsiding after conservative treatment. Plain radiographs were obtained for all patients. Patients without spinal instability, spondylosis, or major osteophytes on plain radiographs and without clinical findings of myelopathy underwent MRI (n = 59) on a 0.5 Tesla superconducting system. The other 41 patients underwent CT myelography. On MRI, herniation of a cervical soft disc was seen in 55 patients and the localisation corresponded well with the clinical symptoms. CT myelography showed a foraminal herniation in one of four selected patients with negative MRI. Fifty of 55 patients underwent ACD. All herniations were confirmed at operation, but in two patients there were important foraminal spurs not seen on MRI. It is concluded that 0.5 T MRI combined with plain radiographs offers an accurate, non-invasive test in the assessment of selected patients with cervical radiculopathy.

Disco-computed tomography in extraforaminal and foraminal lumbar disc herniation: influence on surgical approaches.

Between January 1990 and February 1992, a total of 301 patients underwent discectomy for lumbar disc herniation; 29 had an extreme lateral herniation, i.e., foraminal or extraforaminal. The intervertebral foramen is a three-dimensional area demarcated primarily by the pedicles; we call it the lateral interpedicular compartment. The extraforaminal zone is the space outside the lateral border of the pedicles. All patients were evaluated by computed tomography (CT), water soluble myelography, postmyelographic CT scanning, or magnetic resonance imaging. Fifteen patients consecutively underwent disco-enhanced CT to adjust a correct diagnosis and to distinguish extraforaminal from foraminal herniation. In 10 cases of extraforaminal herniation, a selective radicular decompression with good-to-excellent clinical results was achieved by an extra-axial lateral decompression of the interpedicular compartment, with preservation of the facet joint. The operative target was the lateral aspect of the pars interarticularis and not the intertransverse space, as previously described. In two cases of both foraminal and extraforaminal herniation, the same technique was used. Fourteen patients with foraminal disc herniation and three patients with both foraminal and extraforaminal herniation underwent a standard intervertebral foraminotomy. An accurate preoperative diagnosis established by disco-CT is crucial in order to select the most suitable surgical approach.

Long-term pain relief during spinal cord stimulation. The effect of patient selection.

We reviewed our experience with spinal cord stimulation (SCS) in treating 116 patients with pain in one or both legs. All these patients were selected for an initial week of trial stimulation by the criteria: pain due to a known benign organic cause, failure of conventional pain control methods and absence of major personality disorders. Selected patients included 78 with the Failed Back Surgery Syndrome (FBSS), in whom proven correlation existed between the clinical picture and the neuroradiological and electromyogram abnormalities. Eighty-four out of 116 selected patients underwent definitive SCS implantation after 1 week of trial stimulation with excellent results (more than 75% pain relief). They were followed clinically every 3 months for a mean follow-up period of 47 months. Forty-five patients (54%) continued to experience at least 50% of pain relief at the latest follow up. Seventy-seven patients (91%) were able to reduce their medication intake and 50 patients (60%) reported an improvement in lifestyle. FBSS patients responded more positively to the trial stimulation than the other patients. However, the later outcome was not affected by patient selection as long-term benefit was similar in all definitive SCS patients irrespective of aetiology.

The association of meningioma and pituitary adenoma: report of seven cases and review of the literature.

Seven patients with the co-occurrence of meningioma and pituitary adenoma are reported. Diagnosis was based on histological examination and if not available on MR imaging. Extensive review of the literature reveals only 18 other cases with this association if meningiomas appearing after radiation therapy for pituitary tumors are excluded. As in isolated meningiomas, the female-to-male ratio is high. A preponderance of perisellar meningiomas is apparent. Another distinct characteristic of this combination is not revealed, since no specific typing of the meningioma and no specific endocrine syndrome is uncovered. Two patients presented with multiple meningiomas, of which one showed two histologically different tumor types. The presence of other tumors in association with pituitary adenomas and meningiomas in our series is striking and could suggest a genetic dysregulation leading to the development of these tumors.

Postsurgical follow-up by MRI of anterior cervical discectomy without fusion.

Postoperative magnetic resonance imaging (MRI) findings are described in selected patients with cervical radiculopathy and a cervical soft disc herniation, treated by anterior cervical discectomy (ACD) without fusion. Six months postoperatively, 45 patients underwent MRI examination using a 0.5 T superconductive unit. T1- and T2-weighted spin echo sequences were acquired on sagittal and axial planes. A low signal intensity on T2-weighted images was visualized at the ACD level in all patients. Five patients were found to have a slight kyphosis at the discectomy level. There was no residual disc material at any ACD level. In 5 patients, areas of diminished signal intensity on T1- and T2-weighted images on adjacent vertebrae was noticed, indicating sclerosis of the cortical bone adjacent to the ACD level. In 3 patients, cervical disc protrusions without impression on the dura were visualized postoperatively: 2 below and 1 above the ACD level. One patient developed a cervical disc herniation without complaints one level above the operated one. No patient developed infolding or degenerative swelling of the ligamenta flava and no intrinsic cord abnormalities were present. MRI provided useful information on pathology, allowing a non-invasive evaluation following ACD and enabling a better understanding of surgical consequences.

MR imaging of tuberculous spondylitis.

This case report describes a patient presenting with symptoms of progressive paresis of both legs. An X-ray of the thorax demonstrated an aspect consistent with miliary tuberculosis. Magnetic resonance imaging (MRI) of the thoracic spine revealed medullary compression. The patient underwent a laminectomy and the diagnosis of spinal epidural tuberculoma was made. The patient has been treated with isoniazid, rifampicin and pyrazinamide. After a period of six months, she made a complete recovery.

The association of astrocytoma and pituitary adenoma in a patient with alcaptonuria.

A female patient with a juvenile pilocytic astrocytoma and a pituitary adenoma is described. The patient also has alcaptonuria, a rare inborn error of metabolism with autosomal recessive mode of inheritance. The association of these three disorders has never been reported previously. The possible existence of a common genetic factor in the development of both tumors and alcaptonuria is discussed.

Loss of constitutional heterozygosity in human astrocytomas.

Inactivation of tumour suppressor genes or anti-oncogenes as well as activation of dominant acting oncogenes seem to be important mechanisms in the pathogenesis of gliomas. We compared constitutional and tumoural genotypes at different restriction fragment length polymorphism loci (RFLP) on chromosomes 10 and 17 in 15 unrelated individuals. Loss of heterozygosity (LOH) pointing to chromosomal loss or deletions was detected for at least one chromosome 17 marker in 11 gliomas (astrocytomas grades I-III and glioblastoma multiforme), whereas LOH for chromosome 10 loci was only detected in 3 out of 9 cases of glioblastoma multiforme and was not detected in low grade gliomas. Since LOH for chromosome 10 loci seems to be restricted only to glioblastoma multiforme, it is possible that recessive mutations on chromosome 10 are engaged in tumour progression from astrocytomas to glioblastoma multiforme. As LOH of chromosome 17 markers occurs in astrocytomas as in glioblastoma multiforme, chromosome 17 loci probably are involved in early tumour development.

Postpartum dissecting aneurysm of the basilar artery.

BACKGROUND AND PURPOSE: Dissecting aneurysms arising from the vertebrobasilar complex are rare and difficult to manage. More of their natural history needs to be known before treatment can be optimized. CASE DESCRIPTION: We report a postpartum dissecting aneurysm of the right vertebrobasilar artery in a 31-year-old woman that was confirmed by angiographic identification of a double lumen. The intracranial segment of the right vertebral artery was thrombosed proximal to the aneurysm. The patient, managed conservatively, recovered well and, when reexamined 2 months later, was found to be neurologically intact. A repeat angiographic study at that time demonstrated that the aneurysm had resolved. CONCLUSIONS: Proximal occlusion may have protected the aneurysm from rupture and further dissection, thereby making surgery unnecessary.