Solitary fibrous tumor of the spinal cord.

We report a case of primary solitary fibrous tumor occurring in the intramedullary thoracic spinal cord in a 47-year-old man. The tumor predominately consisted of spindle cells separated by abundant collagen; a few areas of hemangiopericytomatous morphology were also present. The diagnosis was confirmed by immunohistochemistry and electron microscopy. The tumor was reactive to vimentin and CD34 but was negative for glial fibrillary acid protein (GFAP), S-100, smooth muscle actin, epithelial membrane antigen, HMB-45, myelin basic protein, and keratin; ultrastructural examination showed fairly undifferentiated cells within a collagenous matrix, few tight junctions, and sparse extravascular basement membrane. The occurrence of this tumor within the spinal cord parenchyma and in other extraserosal sites emphasizes the current belief that solitary fibrous tumors arise from mesenchymal tissues and are not restricted to the pleura and other serosal surfaces. Furthermore, solitary fibrous tumor is an entity that must be considered in the differential diagnosis of spindle cell central nervous system neoplasms.

Bradykinin and neuronal injury.

Bradykinin, a nine-amino-acid peptide formed from a large precursor polypeptide (kininogen) by the action of the enzyme kallikrein (kininogenase), is the initial mediator of inflammation, and, in particular, bradykinin induces pain and alters vascular permeability. Bradykinin is one of the first compounds produced at the site of tissue injury and subsequently initiates a cascade of reactions that produce the cardinal features of inflammation. We will explore the role that bradykinin plays in various types of neuronal injury. In particular, we will focus on the role that bradykinin and other kinins play in brain and spinal cord trauma, in the pathophysiology of subarachnoid and intraparenchymal hemorrhage and ischemia, and in the initiation of nociceptive pain. This role suggests that bradykinin antagonists may be clinically useful in the therapeutic management of neurosurgical patients.

Operative positioning for patients undergoing repair of craniosynostosis.

A further modification of our operative positioning protocol is presented, with several novel approaches to positioning that give only slightly less exposure than that obtained with the modified prone position, but that enable the entire cranial vault remodeling to be done in one operation. The addition of two techniques has obviated both the need to use the modified prone position (except in certain difficult cases) in recent years and the need to get preoperative cervical spine film evaluation. Two new operative positioning techniques that enable a large calvarial exposure are described: one (the gel-filled collar technique) focuses on the more anterior portion of the cranial vault, and the other (the angled horseshoe technique) focuses on the posterior portion; both provide an extensive exposure of the opposite portion of the calvarium.

Acrylic cranioplasty using miniplate struts.

OBJECTIVE: Cranioplasty using acrylic is a common procedure in patients with cranial defects secondary to trauma, infection, or tumor. The limitations of this technique include poor adherence of the acrylic to surrounding bone and difficulty in achieving a proper cosmetic contour in complicated cranial defects, especially those involving the orbital rim. The authors have been continually developing techniques of cranioplasty. METHODS: Ten consecutive cranioplasties were performed over the past 5 years using this new technique. TECHNIQUE: The authors describe a technique using miniplates as struts to which the acrylic is applied using a "reinforced concrete" principle. RESULTS/CONCLUSION: All patients achieved excellent cosmetic results with no complications. This technique allows contour of the repair site while the acrylic is curing and provides a more resilient resulting prosthesis.

Enhancing nerve regeneration across a silicone tube conduit by using interposed short-segment nerve grafts.

Isolated nerve segments may inherently contain all of the necessary factors required to support regeneration within a silicone tube conduit placed across a nerve gap. Thirty-six adult Lewis rats each weighing approximately 250 g were randomized into three groups. A sciatic nerve gap (13-15 mm in length) was bridged by an empty silicone tube (Group I), a silicone tube containing a short 2-mm interposed nerve segment (Group II), or a nerve autograft (Group III). At 16 weeks postoperatively, no regeneration was observed through the empty silicone tube. In contrast, regeneration across the silicone tube containing the isolated nerve segment was equivalent to that noted through nerve autografts as assessed by histological, electrophysiological, and functional criteria. Thus, an interposed nerve segment will extend the length of successful nerve regeneration through a silicone tube conduit.

Frontal plagiocephaly secondary to synostosis of the frontosphenoidal suture. Case report.

Frontal plagiocephaly may arise from either synostotic or deformational forces. Deformational causes of frontal plagiocephaly can be distinguished from synostotic causes by differences seen on physical examination, which can then be confirmed by skull x-ray films and if necessary three-dimensional computerized tomography (CT). Unilateral coronal synostosis is the main synostotic cause of frontal plagiocephaly, although it has also been seen with fusion of the frontozygomatic suture. In several syndromes presenting with bilateral coronal synostosis, fusion of the frontosphenoidal and frontoethmoidal sutures is also present. The authors report, for perhaps the first time, a case showing synostotic frontal plagiocephaly secondary to fusion of the frontosphenoidal suture alone. Although the phenotypic appearance is superficially similar to that seen in unilateral coronal synostosis, analysis of the cranial base shows markedly different effects: angulation of the anterior cranial base with respect to the posterior cranial base away from the synostotic side and angulation of the posterior cranial base with respect to the midpalatal suture also away from the synostotic side. In unilateral coronal synostosis, both angulations are toward the synostotic side. These effects on the cranial base alter its relationship to the cranial vault and the facial skeleton. Most important, frontal plagiocephaly secondary to fusion of the frontosphenoidal suture should not be overlooked as being deformational. Because this fusion is difficult or impossible to visualize by skull x-ray films, three dimensional CT must be obtained in cases that are not clearly identified as deformational plagiocephaly by physical examination.

Optimizing accuracy in magnetic resonance imaging-guided stereotaxis: a technique with validation based on the anterior commissure-posterior commissure line.

OBJECT: Some of the earliest successful frame-based stereotactic interventions directed toward the thalamus and basal ganglia depended on identifying the anterior commissure (AC) and posterior commissure (PC) in a sagittal ventriculogram and defining the intercommissural line that connects them in the midsagittal plane. The AC-PC line became the essential landmark for the localization of neuroanatomical targets in the basal ganglia and diencephalon and for relating them to stereotactic atlases. Stereotactic/functional neurosurgery has come to rely increasingly on magnetic resonance (MR) imaging guidance, and methods for accurately determining the AC-PC line on MR imaging are being developed. The goal of the present article is to present the authors' technique. METHODS: The technique described uses MR sequences that minimize geometric distortion and registration error, thereby maximizing accuracy in AC-PC line determinations from axially displayed MR data. The technique is based on the authors' experience with the Leksell G-frame but can be generalized to other MR imaging-based stereotactic systems. This methodology has been used in a series of 62 stereotactic procedures in 47 adults (55 pallidotomies and seven thalamotomies) with preliminary results that compare favorably with results reported when using microelectrode recordings. The measurements of the AC-PC line reported here also compare favorably with those based on ventriculography and computerized tomography scanning. CONCLUSIONS: The methodology reported here is critical in maintaining the accuracy and utility of MR imaging as its role in modern stereotaxy expands. Accurate parameters such as these aid in ensuring the safety, efficacy, and reproducibility of MR-guided stereotactic procedures.

Limiting ischemic spinal cord injury using a free radical scavenger 21-aminosteroid and/or cerebrospinal fluid drainage.

Traumatic spinal cord injury occurs in two phases: biomechanical injury, followed by ischemia and reperfusion injury. Biomechanical injury to the spinal cord, preceded or followed by various pharmaceutical manipulations or interventions, has been studied, but the ischemia/reperfusion aspect of spinal cord injury isolated from the biomechanical injury has not been previously evaluated. In the current study, ischemia to the lumbar spinal cord was induced in albino rabbits via infrarenal aortic occlusion, and two interventions were analyzed: the use of U74006F (Tirilazad mesylate), a 21-aminosteroid, and cerebrospinal fluid (CSF) drainage. These treatment modalities were tested alone or in combination. In Phase 1 of this study, the rabbits received 1.0 mg/kg of Tirilazad or an equal volume of vehicle (controls) prior to the actual occlusion, three doses of Tirilazad (1 mg/kg each) during the occlusion, then several doses after the occlusion. Of the Tirilazad-treated animals, 30% became paraplegic while 70% of the control animals became paraplegic. Phase 2 involved the same doses of Tirilazad as in Phase 1 and, in addition, CSF pressure monitoring and drainage were performed. The paraplegia rate was 79% in the control animals, 36% in the group receiving Tirilazad alone, 25% in the group with CSF drainage alone, and 20% in the Tirilazad plus CSF drainage group. This rate also correlated with changes noted in CSF pressure; both Tirilazad administration alone and CSF drainage alone induced a decrease in CSF pressure and the two combined produced a further decrease. There was marked improvement in the perfusion pressure when using Tirilazad alone, CSF drainage alone, and Tirilazad therapy in combination with CSF drainage, with the last group producing the largest increase. This change in CSF pressure and perfusion pressure correlated with improved functional neurological outcome. Pathological examination revealed that Tirilazad therapy reduced the extensive and diffuse neuronal, glial, and endothelial damage to (in its most severe form) a more patchy focal region of damage in the gray matter. Cerebrospinal fluid drainage resulted in pyknosis of some motor neurons, and some eosinophilia. The combination of CSF drainage and Tirilazad administration resulted in the least abnormality, with either normal or near-normal spinal cords. It is concluded that Tirilazad administration decreased CSF pressure during spinal cord ischemia and reperfusion and, like CSF drainage, increased and improved the perfusion pressure to the spinal cord, decreased spinal cord damage, and improved functional outcome.(ABSTRACT TRUNCATED AT 400 WORDS)

Fast spin-echo magnetic resonance imaging for radiological assessment of neonatal brachial plexus injury.

Neurosurgical management of birth-related brachial plexus palsy involves observing the patient for a period of several months. Operative intervention is usually undertaken at 3 to 6 months of age or more in infants who have shown little or no improvement in affected muscle groups. Ancillary tests such as electromyography and nerve conduction studies are occasionally useful. No radiological study has been consistently helpful in operative planning, except for contrast computerized tomography (CT) myelography, which requires general anesthesia in infants. This is because the infant's small size exceeds the functional resolution of the imaging modalities. This report describes the use of a special sequence of magnetic resonance (MR) imaging entitled "fast spin echo" (FSE-MR). Unlike CT myelography, this technique provides high-speed noninvasive imaging that allows clinicians to evaluate preganglionic nerve root injuries without the use of general anesthesia and lumbar puncture. The utility of this technique is illustrated in three cases, two involving either infraclavicular exploration or a combination of infraclavicular and supraclavicular exposure based on FSE-MR findings. The FSE-MR imaging offers an excellent alternative to contrast CT myelography in evaluation of infants with birth-related brachial plexus injuries.

Neurodevelopment in children with single-suture craniosynostosis and plagiocephaly without synostosis.

The objective of this study was to determine whether children with nonsyndromic craniosynostosis and plagiocephaly without synostosis demonstrated cognitive and psychomotor delays when compared with a standardized population sample. This was the initial assessment of a larger prospective study, which involved 21 subjects with nonsyndromic craniosynostosis (mean age, 10.9 months) and 42 subjects with plagiocephaly without synostosis (mean age, 8.4 months). Each child was assessed using the Bayley Scales of Infant Development-II (BSID-II) for cognitive and psychomotor development before therapeutic intervention (surgery for craniosynostosis and molding-helmet therapy for plagiocephaly without synostosis). The distribution of the scores was divided into four groups: accelerated, normal, mild delay, and significant delay. The distributions of the mental developmental index (MDI) and the psychomotor developmental index (PDI) were then compared with a standardized Bayley's age-matched population, using Fisher's exact chi-square test. Within the craniosynostosis group, the PDI scores were significantly different from the standardized distribution (p < 0.001). With regard to the PDI scores, 0 percent of the subjects in the craniosynostosis group were accelerated, 43 percent were normal, 48 percent had mild delay, and 9 percent had significant delay. In contrast, the MDI scores were not statistically different (p = 0.08). Within the group with plagiocephaly without synostosis, both the PDI and MDI scores were significantly different from the normal curve distribution (p < 0.001). With regard to the PDI scores, 0 percent of the subjects in the group with plagiocephaly without synostosis were accelerated, 67 percent were normal, 20 percent had mild delay, and 13 percent had significant delay. With regard to the MDI scores, 0 percent of the subjects in this group were accelerated, 83 percent were normal, 8 percent had mild delay and 9 percent had significant delay. This study indicates that before any intervention, subjects with single-suture syndromic craniosynostosis and plagiocephaly without synostosis demonstrate delays in cognitive and psychomotor development. Continued postintervention assessments are needed to determine whether these developmental delays can be ameliorated with treatment.