Computer-assisted measurement of lumbar spine radiographs.

RATIONALE AND OBJECTIVES: The authors evaluated a method for obtaining reproducible, reliable measurements from standard lumbar spine radiographs for determining the degree of spondylolisthesis, vertebral body height, intervertebral disk space height, disk space angle, and degree of vertebral body wedging. MATERIALS AND METHODS: Four to six easily defined points were identified on each vertebral body on anteroposterior and lateral plain radiographs of the lumbosacral spine of patients. From these points, the degree of spondylolisthesis, the vertebral body height, the intervertebral disk space height, the disk space angle, and the degree of vertebral body wedging were easily calculated by using well-known geometric relationships. This method requires the use of a personal computer and a standard spreadsheet program but does not require the use of any other specialized radiographic equipment, computer hardware, or custom software. RESULTS: Calculations of intra- and interobserver variability for the measurement of spondylolisthesis, disk space height, disk space angle, and vertebral body height measurement showed that the technique is extremely reproducible. CONCLUSION: This technique may prove useful in the prospective evaluation of potential candidates for lumbar spinal stenosis surgery.

Internal fixation of the spine using a braided titanium cable: clinical results and postoperative magnetic resonance imaging.

Segmental spinal fixation using sublaminar or interspinous stainless steel wire has been successfully used for many years. Stainless steel cables have been developed that are stronger and more flexible, allowing for shorter operative time and decreased risk of neurological deficit. However, stainless steel implants create significant artifact on magnetic resonance imaging (MRI), reducing the postoperative usefulness of this imaging modality. Titanium instrumentation has the advantage of producing minimal MRI artifact. Recently, a braided titanium cable has been developed that has the advantages of strength and flexibility as well as minimal production of MRI artifact. We present a series of 50 patients who underwent internal fixation of the spine using a braided titanium cable either alone or in combination with supplementary titanium instrumentation. No instrument failures have occurred to date. Postoperative MRI scans have revealed minimal implant-related artifact, allowing for high-resolution, noninvasive postoperative imaging of the neuraxis. We conclude that braided titanium cable has significant advantages over stainless steel cable or monofilament wire and is a valuable instrument for segmental spine fixation.

Dolichoectasia of the anterior cerebral arteries in an adolescent.

We report a case of bilateral dolichoectasia of the anterior cerebral arteries in a 14-year-old girl as documented by MR imaging and cerebral angiography. Concurrent thickening of the adjacent medial frontal lobes was found, suggesting either a neuronal migrational abnormality or secondary changes attributable to vascular insufficiency.

Gene expression from recombinant viral vectors in the central nervous system after blood-brain barrier disruption.

Direct intracerebral injection of recombinant adenoviral vectors within the brain parenchyma or the ventricular system results in a limited volume of distribution of virus, as demonstrated by transgene expression. Global delivery to the central nervous system may increase the use of these vectors but only if the viral vectors can cross the blood-brain barrier and result in transduction of the underlying cells. This short-term study examines whether osmotic disruption with mannitol can result in sufficient opening of the vascular endothelium to allow for passage of replication-defective adenovirus containing the Escherichia coli beta-galactosidase gene (lacZ). Virus was injected into the carotid artery of rats after blood-brain barrier disruption with intracarotid hypertonic mannitol, and the animals were killed and analyzed after 4 days. Histochemical analysis and electron microscopy confirmed expression of the E. coli lacZ gene in the pericapillary astrocytes of the ipsilateral cerebral cortex and deep grey matter. Furthermore, the extent of gene transfer and expression correlated with the degree of barrier opening, as measured by Evans blue staining. Transgene expression was not seen in control animals that received intracarotid saline before recombinant virus injection. These data demonstrate, for the first time, that blood-brain barrier disruption can allow for the delivery of functional viral vectors to the central nervous system.

Bone formation within a choroid plexus papilloma.

Bone formation within the choroid plexus papillomas is rare, with only 4 previous cases reported. We present a case of a 12-year-old boy who presented with papilledema, visual loss and hydrocephalus who was found to have a choroid plexus papilloma. Histological analysis of the tumor revealed foci of cancellous bone formation with hematopoietic cells within the marrow spaces. We review the proposed mechanisms for bone formation within neuroepithelial brain tumors.

Characterization of naturally occurring cutaneous neurofibromatosis in Holstein cattle. A disorder resembling neurofibromatosis type 1 in humans.

Neurofibromatosis in cattle is typically a noncutaneous disease. A small group of cows in a Holstein dairy herd developed cutaneous neurofibromatosis. This unique condition was investigated and compared with neurofibromatosis type 1 (NF1) in humans. All cutaneous lesions but one were consistent with neurofibromas in noncutaneous sites in cattle and neurofibromas in patients with NF1. One bovine lesion was classified as a neurofibrosarcoma. Immunohistochemistry and electron microscopy supported Schwannian differentiation in benign and malignant lesions. Linkage analysis with a polymorphism in the bovine NF1 gene confirmed that two affected animals from the same sire inherited the same paternal NF1 allele. Bovine cutaneous neurofibromatosis is a naturally occurring disease in this group of animals, characterized by skin tumors morphologically identical to those of NF1. An informative polymorphism at the NF1 locus of two animals and their sire suggests this disorder may be caused by hereditary mutations at the bovine NF1 locus.

Outcome after laminectomy for lumbar spinal stenosis. Part I: Clinical correlations.

All patients who underwent decompressive lumbar laminectomy in the Washtenaw County, Michigan metropolitan area during a 7-year period were studied for the purpose of defining long-term outcome, clinical correlations, and the need for subsequent fusion. Outcome was determined by questionnaire and physical examination from a cohort of 119 patients with an average follow-up evaluation interval of 4.6 years. Patients graded their outcome as much improved (37%), somewhat improved (29%), unchanged (17%), somewhat worse (5%), and much worse (12%) compared to their condition before surgery. Poor outcome correlated with the need for additional surgery, but there were few additional significant correlations. No patient had a lumbar fusion during the study interval. The outcome after laminectomy was found to be less favorable than previously reported, based on a patient questionnaire administered to an unbiased patient population. Further randomized, controlled trials are therefore necessary to determine the efficacy of lumbar fusion as an adjunct to decompressive lumbar laminectomy.

Outcome after laminectomy for lumbar spinal stenosis. Part II: Radiographic changes and clinical correlations.

The pre- and postoperative lumbar spine radiographs of 119 patients who underwent decompressive lumbar laminectomy were studied to evaluate radiographic changes and to correlate them with clinical outcome. An accurate and reproducible method was used for measuring pre- and postoperative radiographs that were separated by an average interval of 4.6 years. Levels of the spine that underwent laminectomy showed greater change in spondylolisthesis, disc space angle, and disc space height than unoperated levels. Outcome correlated with radiographic changes at operated and unoperated levels. This study demonstrates that radiographic changes are greater at operated than at unoperated levels and that some postoperative symptoms do correlate with these changes. Lumbar fusion should be considered in some patients who undergo decompressive laminectomy. The efficacy of and unequivocal indications for lumbar fusion can only be determined from randomized, prospective, controlled trials, however, and these studies have not yet been undertaken.

Uncomplicated stereotactic and open neurosurgical procedures in patients with factor VII deficiency.

Factor VII deficiency is characterized by epistaxis, bruising, hemarthrosis, menorrhagia, gastrointestinal bleeding, hematuria, and intracranial hemorrhage during infancy. Causes of acquired factor VII deficiency include liver disease, Vitamin K deficiency, and warfarin administration. Congenital factor VII deficiency is an autosomal recessive disorder, with the homozygotes having a severe deficiency and the heterozygotes a moderate deficiency of factor VII. Orthopedic, gynecological, cardiothoracic, and abdominal surgical procedures have been successfully performed in patients with factor VII deficiency both with and without factor VII replacement. We present two patients with moderate and moderately severe factor VII deficiency who successfully underwent intracranial procedures using plasma during the perioperative period for factor VII replacement. One patient successfully underwent stereotactic placement of mesial temporal lobe depth electrodes and subdural strip electrodes followed by anterior temporal lobectomy for medically refractory seizures. The second patient successfully underwent craniotomy for an olfactory groove meningioma. No bleeding complications were encountered with any of the three intracranial procedures performed. These cases represent the first reported cases of successful intracranial procedures in patients with factor VII deficiency, other than shunting procedures performed for intraventricular hemorrhage during infancy.

Expression of Escherichia coli beta-galactosidase and rat HPRT in the CNS of Macaca mulatta following adenoviral mediated gene transfer.

Adenoviral-mediated gene transfer to the caudate nucleus of Macaca mulatta was accomplished using stereotactic injection of two distinct recombinant Ad5 vectors containing the gene for Escherichia coli beta-galactosidase and the cDNA for rat hypoxanthine-guanine phosphoribosylphosphotransferase (HPRT), respectively. Multiple analyses (including immunohistochemistry, histochemistry, transmission electron microscopy, RNA in situ hybridization, nucleotide pool analysis, and enzyme assay) confirmed efficient expression of beta-galactosidase and rat HPRT. Transgene expression was evident in both neurons and glia. Clinically, no evidence of meningitis or cerebritis was observed and no focal neurological deficits were detected in the animal. These preliminary studies indicate that recombinant adenovirus is capable of mediating high level transgene expression to the brains of higher order mammals.

Magnetic resonance imaging documentation of coexistent traumatic locked facets of the cervical spine and disc herniation.

The coexistence of traumatic locked facets of the cervical spine and a herniated disc is not well described. The authors present a series of patients with traumatic locked facets who demonstrated a high incidence of associated disc herniation documented on magnetic resonance (MR) imaging. Thirteen patients with either unilateral (four cases) of bilateral (nine cases) locked facets of the cervical spine were analyzed retrospectively. Immediate closed reduction using traction and/or manipulation was attempted in the first nine cases treated and was successful in only three; however, the procedure was abandoned in three cases due to deterioration in the patient's clinical status. In the subsequent four patients, an MR image was obtained prior to attempts at closed reduction. All patients underwent MR imaging of the cervical spine. Of eight consecutive cases treated at the University of Michigan, frank disc herniation with fragmented disc in the canal was found in five while pathological disc bulging was found in the other three. All five cases contributed by other institutions had concurrent disc herniation. This series illustrates the importance of using MR imaging to document the presence of a herniated disc during the initial evaluation of a patient with traumatic locked facets of the cervical spine and prior to attempted reduction of the locked facets. Experience indicates that closed reduction of facet dislocation associated with disc rupture may result in increased spinal cord compression and neurological deficit. If a herniated disc is discovered, anterior discectomy and fusion would be favored as the initial therapy over attempts at closed reduction or operative posterior reduction.