bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic resonance imaging-monitored conservative management of traumatic spinal epidural hematomas
Authors: La Rosa Giovanni , d'Avella Domenico , Conti Alfredo , Cardali Salvatore , La Torre Domenico , Cacciola Fabio , Longo Marcello , Tomasello Francesco
Published: January 2008

Spinal epidural hematomas (SEHs) are uncommon complications caused by traumatic injuries to the spine. Emergency surgical evacuation is the standard treatment. Although recognized in the literature, the possibility of nonsurgical treatment of traumatic SEHs is far from being codified. The authors report on the treatment of four patients whose traumatic SEHs were diagnosed by magnetic resonance (MRI) imaging and managed conservatively with excellent results.

All patients had suffered severe spine injury with fracture of a lumbar vertebral body, were admitted within 12 hours of trauma, and exhibited only minimal neurological disturbances on admission. Magnetic resonance imaging studies were performed within 24 hours of trauma. Hematomas appeared isointense/slightly hyperintense on T1- and heterogeneous on T2-weighted MR images. Clot thickness varied between 0.8 cm and 1 cm, width between 1 cm and 1.8 cm, and length between 2.7 and 9 cm. In light of each patient's fairly good neurological condition a conservative approach was taken. In all cases serial MR imaging documented progressive clot resolution, which was completed within 8 to 10 days of trauma. At discharge all patients were neurologically intact.

The conservative treatment option of traumatic SEH should be reserved for exceptional cases whose deficits are minimal, when neurological deterioration is followed by early and sustained spontaneous recovery, and when there are clear medical contraindications for surgery. The results of the present study confirm that nonsurgical treatment is feasible in a subgroup of minimally symptomatic patients who harbor moderate-sized SEHs. Although the authors' experience shows a good spontaneous outcome of some traumatic SEH, further studies are necessary to understand the real spectrum of nonsurgical treatment of such lesions.
Surgery in epilepsy associated with focal lesions in childhood
Authors: Bourgeois Marie , Sainte-Rose Christian , Lellouch-Tubiana Arielle , Malucci Conor , Brunelle Francis , Maixner Wirginia , Cinalli Giuseppe , Pierre-Kahn Alain , Renier Dominique , Zerah Michel , Hirsch Jean-François , Goutières Francoise , Aicardi Jean
Published: January 2008

Surgery in children with epilepsy is a new, evolving field. The important practical issues have been to define strategies for choosing the most suitable candidates, as well as the type and the optimum timing of epilepsy surgery. This study was undertaken to illustrate these points.

To identify the factors that correlated with outcome, the authors analyzed a series of 200 children (aged 1–15 years, mean 8.7 years) who underwent surgery at the Hôpital Necker-Enfants Malades between 1981 and 1996. In 171 cases (85.5%) the epilepsy was medically refractory and was associated with focal cortical lesions. Surgery consisted of resection of the lesion without specifically attempting to identify and remove the "epileptogenic area."

In the group of children whose seizures were medically refractory, the mean follow-up period was 5.8 years. According to Engel's classification, 71.3% of these children became seizure free (Ia), whereas 82% were in Class I. A multivariate statistical analysis revealed that among all the factors studied, the success of surgery in a patient in whom there was a good clinical-electroencephalogram-imaging correlation, depended on the patients' having undergone a minimally traumatic operation, a complete resection of the lesion, and a short preoperative seizure duration.

After the surgical control of epilepsy, behavior disorders were more improved (31% of all patients) than cognitive function (25%). The patient age at onset, duration and frequency of seizures, intractability of the disease to therapy, and seizure characteristics, were correlated with cognitive, behavioral, and academic performance pre- and postoperatively. Multivariate statistical analysis revealed that cognitive dysfunction correlated highly with the duration of epilepsy prior to surgery, whereas behavioral disorders correlated more with seizure frequency.

These data must be taken into account when selecting patients for surgical treatment and when deciding the timing of surgery. Early surgical intervention allows for optimum brain development.
A mobile high-field magnetic resonance imaging system for neurosurgery
Authors: Sutherland Garnette R. , Kaibara Taro , Louw Deon , Saunders John
Published: January 2008

The authors' goal was to place a mobile, 1.5 tesla magnetic resonance (MR) imaging system into a neurosurgical operating room without adversely affecting established neurosurgical management. The system would help to plan accurate surgical corridors, confirm the accomplishment of operative objectives, and detect acute complications such as hemorrhage or ischemia.

The authors used an actively shielded 1.5 tesla magnet, together with 15 m tesla/m gradients, MR console computers, gradient amplifiers, a titanium, hydraulic-controlled operating table, and a radio frequency coil that can be disassembled. The magnet is moved to and from the surgical field by using overhead crane technology. To date, the system has provided unfettered access to 46 neurosurgical patients.

In all patients, high-definition T1- and/or T2-weighted images were rapidly and reproducibly acquired at various stages of the surgical procedures. Eleven patients underwent craniotomy that was optimized after pre-incisional imaging. In four patients who harbored subtotally resected tumor, intraoperative MR imaging allowed removal of remaining tumor. Interestingly, the intraoperative administration of gadolinium in the management of patients with malignant glioma demonstrated a dynamic expansion of enhancement beyond the preoperative contrast contour. These zones of new enhancement proved, on examination of biopsy sample, to be tumor.

The authors have demonstrated that high-quality MR images can be obtained within reasonable time constraints in the operating room. Procedures can be conducted without compromising or altering traditional neurosurgical, nursing, or anesthetic techniques. It is feasible that within the next decade intraoperative MR imaging may become the standard of care in neurosurgery.
Neuroendoscopic approach to intraventricular lesions
Authors: Gaab Michael R. , Schroeder Henry W. S.
Published: January 2008

Object

The purpose of this study was to determine the efficacy of endoscopic treatment in patients with intraventricular tumors.

Methods

A series of 30 patients with endoscopically treated intraventricular lesions is reported. The lesions included seven colloid cysts, six astrocytomas, three subependymomas, two ependymomas, and one each of the following: pineoblastoma, pineocytoma/pineoblastoma (intermediate type), epidermoid cyst, pineal cyst, medulloblastoma, arteriovenous hemangioma, cavernoma, choroid plexus papilloma, pituitary adenoma, craniopharyngioma, melanoma, and germinoma. Total tumor resections, partial resections, biopsies, stent implantations, septostomies, and third ventriculostomies were performed. In two cases (two subependymomas > 2 cm in diameter), piecemeal endoscopic resection was ineffective because of the very firm consistency of the tumors. Therefore the endoscopic procedure was discontinued and the tumors were removed microsurgically. In the remaining cases the procedures were completed as planned. Even in the presence of difficulties such as poor orientation or significant bleeding, there was no need to abandon the endoscopic procedure. A total of 28 strictly endoscopic interventions were performed, in which the average duration was 85 minutes (range 35–170 minutes). All colloid cysts and the epidermoid lesion were completely evacuated and the capsules were widely resected. Total extirpation of solid tumors was achieved in five cases, whereas most astrocytomas were partially resected. The hydrocephalus-related symptoms resolved in all of the 22 patients with cerebrospinal fluid pathway obstruction. There were no endoscopy-related deaths. In two cases, major bleeding occurred and was controlled endoscopically. The authors observed one case of meningitis, one of mutism, two of memory loss attributed to forniceal injury, one of transient trochlear palsy after a biopsy specimen of an aqueductal tumor was obtained, and one of transient confusion after a biopsy specimen of a germinoma was obtained.

Conclusions

In the authors' preliminary experience, the endoscopic approach was found to be safe and effective. In this series, it was possible to achieve relief of noncommunicating hydrocephalus, tumor resections, and even complete tumor removals by using endoscopic techniques. Based on the results, the authors believe that endoscopic techniques should be considered in the treatment of selected intraventricular lesions.
Combined fetal neural transplantation and nerve growth factor infusion: effects on neurological outcome following fluid-percussion brain injury in the rat
Authors: Sinson Grant , Voddi Madhu , McIntosh Tracy K.
Published: January 2008

This study was designed to evaluate the histological and behavioral impact of fetal neural transplantation with and without neurotrophin infusion in rats subjected to traumatic brain injury using a clinically relevant model of lateral fluid-percussion brain injury. Adult male Sprague-Dawley rats received lateral fluid-percussion brain injury of moderate severity (2.1-2.3 atm). Twenty-four hours after injury, minced fetal cortical grafts (E16) were stereotactically transplanted into the site of injury cavity formation (in 32 rats). Ten control animals received injections of saline. A third group of 29 animals that received transplants also underwent placement of a miniosmotic pump (immediately after transplantation) to continuously infuse nerve growth factor (NGF) directly into the region of graft placement for the duration of the experiment. A fourth group of eight animals underwent transplantation of fetal cortical cells that had been dissociated and placed in suspension. Animals were evaluated at 72 hours, 1 week, and 2 weeks after injury for cognitive function (using the Morris water maze), posttraumatic motor dysfunction, and transplant survival and morphology (using Nissl and modified Palmgren's silver staining techniques). Robust survival of whole-tissue transplants was seen in 65.6% of animals and was not increased in animals receiving NGF infusion. Animals receiving transplants of cell suspension had no surviving grafts. Brain-injured animals receiving transplants showed significant cognitive improvements compared with controls at the 2-week evaluation. Significantly improved memory scores were seen at all evaluation times in animals receiving both NGF and transplants compared with injured controls and compared with animals receiving transplants alone at the 72-hour and 1-week evaluations. Neurological motor function scores were significantly improved in animals receiving transplants alone and those receiving transplants with NGF infusion. Histological evaluation demonstrated differentiation of grafted cells, decreased glial scarring around transplants when compared with control animals, and the presence of neuronal fibers bridging the interface between graft and host. This study demonstrates that fetal cortical cells transplanted into the injured cortex of the adult rat can improve both posttraumatic cognitive and motor function and interact with the injured host brain.
Motor nerve transplantation
Authors: Gray William P. , Keohane Catherine , Kirwan William O.
Published: January 2008

The motor nerve transplantation (MNT) technique is used to transfer an intact nerve into a denervated muscle by harvesting a neurovascular pedicle of muscle containing motor endplates from the motor endplate zone of a donor muscle and implanting it into a denervated muscle. Thirty-six adult New Zealand White rabbits underwent reinnervation of the left long peroneal (LP) muscle (fast twitch) with a motor nerve graft from the soleus muscle (slow twitch). The right LP muscle served as a control. Reinnervation was assessed using microstimulatory single-fiber electromyography (SFEMG), alterations in muscle fiber typing and grouping, and isometric response curves. Neurofilament antibody was used for axon staining. The neurofilament studies provided direct evidence of nerve growth from the motor nerve graft into the adjacent denervated muscle. Median motor endplate jitter was 13 μsec preoperatively, and 26 μsec at 2 months, 29.5 μsec at 4 months, and 14 μsec at 6 months postoperatively (p < 0.001). Isometric tetanic tension studies showed a progressive functional recovery in the reinnervated muscle over 6 months. There was no histological evidence of aberrant reinnervation from any source outside the nerve pedicle. Isometric twitch responses and adenosine triphosphatase studies confirmed the conversion of the reinnervated LP muscle to a slow-type muscle. Acetylcholinesterase studies confirmed the presence of functioning motor endplates beneath the insertion of the motor nerve graft. It is concluded that the MNT technique achieves motor reinnervation by growth of new nerve fibers across the pedicle graft into the recipient muscle.
Characterization of a model of hydrocephalus in transgenic mice
Authors: Cohen Alan R. , Leifer David , Zechel Marc , Flaningan Daniel P. , Lewin Jonathan S. , Lust W. David
Published: January 2008

The purpose of this study was to elucidate the pathophysiology of hydrocephalus in a new transgenic model of mice created to overproduce the cytokine, transforming growth factor-ß1 (TGFß1), in the central nervous system (CNS).

Galbreath and colleagues generated transgenic mice that overexpressed TGFß1 in the CNS in an effort to examine the role of this cytokine in the astrocytic response to injury. Unexpectedly, the animals developed severe hydrocephalus and died. The authors perpetuated this transgenic colony to serve as a model of congenital hydrocephalus, breeding asymptomatic carrier males that were heterozygous for the transgene with wild-type females.

One hundred twelve (49.6%) of 226 mice developed clinical manifestations of hydrocephalus, which was characterized by dorsal doming of the calvaria, spasticity, limb tremors, ataxia, and ultimately death. The presence of the TGFß1 transgene was determined by performing polymerase chain reaction (PCR) analysis of sample cuts of tail. The animals with the hydrocephalic phenotype consistently carried the transgene, although some animals with the transgene did not develop hydrocephalus. Animals without the transgene did not develope hydrocephalus.

Alterations in brain structure were characterized using magnetic resonance (MR) imaging, gross and light microscopic analysis, and immunocytochemistry. Magnetic resonance imaging readily distinguished hydrocephalic animals from nonhydrocephalic controls, and it demonstrated an obstruction at the outlets of the fourth ventricle. Gross and light microscopic examination confirmed the MR findings. The results of immunofluorescent staining of brain tissue slices revealed the presence of the TGFß1 cytokine and its receptor preferentially in the meninges and subarachnoid space in both hydrocephalic and control mice. Reverse transcriptase-PCR analysis demonstrated tissue-specific expression of the TGFß1 gene in the brains of transgenic mice, and enzyme-linked immunosorbent assay confirmed the occurrence of overexpression of the TGFß1 cytokine in brain, cerebrospinal fluid, and plasma.

The transgenic murine model provides a reproducible representation of congenital hydrocephalus. The authors hypothesize that overexpression of TGFß1 in the CNS causes hyrdocephalus by altering the environment of the extracellular matrix and interfering with the circulation of cerebrospinal fluid. A model of hydrocephalus in which the genetic basis is known should be useful for evaluating hypotheses regarding the pathogenesis of this disorder and additionally, should help in the search for novel treatment strategies.
Microendoscopic posterior cervical foraminotomy: a cadaveric model and clinical application for cervical radiculopathy
Authors: Burke Timothy G. , Caputy Anthony
Published: January 2008

Cervical radiculopathy that is caused by either soft herniated disc material or foraminal stenosis is a common problem. Anterior and posterior surgical approaches are commonly performed to decompress the nerve root. The authors describe an endoscopic posterior foraminotomy procedure in which they use a rigid endoscope, in both a cadaveric model and in three clinical cases, including a multiple level case.

Postoperatively, all patients returned to functional work status within 4 weeks. The mean length of hospitalization was 1.3 days.

The advantages of this technique include improved visualization, a smaller incision, and significantly less postoperative discomfort when compared with a matched group of patients in whom open nonendoscopic foraminotomy has been performed.
Microendoscopic approach to far-lateral lumbar disc herniation
Authors: Foley Kevin T. , Smith Maurice M. , Rampersaud Y. Raja
Published: January 2008

The purpose of this study was to determine the feasibility of performing far-lateral lumbar discectomy by using the microendoscopic discectomy (MED) technique. The authors studied 11 consecutive patients with unilateral, single-level radiculopathy secondary to far-lateral disc herniation. There were eight men and three women, with an average age of 43 years. In all patients magnetic resonance imaging and/or computerized tomography scanning documented far-lateral disc herniations. Six patients experienced motor deficits, nine patients sensory abnormalities, and five depressed reflexes. All patients complained of radicular pain, which failed to improve with conservative care.

After induction of epidural anesthesia, single-level, unilateral percutaneous discectomies were performed using the MED technique. Five discectomies were performed at L3-4 and six at L4-5. There were four contained and seven sequestered disc herniations. All surgeries were performed on an outpatient basis. Follow up ranged from for 12 to 27 months. Improvement was shown in all patients postoperatively. Using modified Macnab criteria to assess results of surgery, there were 10 excellent results and one good result. None of the patients experienced residual motor deficits, four had residual decreased sensation, and one still had some degree of nonradicular pain. There were no complications.

Although various open techniques exist for the treatment of far-lateral disc herniation, MED is unique in that far-lateral pathological entities can be directly visualized and removed via a 15-mm paramedian incision. The percutaneous approach avoids larger, potentially denervating and destabilizing procedures. The need for general anesthesia can be avoided, and surgery is performed on an outpatient basis, thereby reducing hospital cost and length of stay.
Idiopathic spinal cord herniation
Authors: Miyake Shigeru , Tamaki Norihiko , Nagashima Tatsuya , Kurata Hiromitsu , Eguchi Takahiro , Kimura Hidehiko
Published: January 2008

The authors describe two occurrences of idiopathic spinal cord herniation, an entity that has been reported previously in only 11 cases. The patients described in this report presented in midlife with Brown-Séquard syndrome. Computerized tomography myelography and magnetic resonance (MR) imaging showed ventral displacement of the spinal cord with no apparent dorsal mass. Intraspinal cerebrospinal fluid (CSF) flow studies in which phase-contrast pulse sequence cine MR imaging was used displayed a normal pattern dorsal to the spinal cord. Percutaneous intrathecal endoscopic observation did not disclose dorsal intradural cysts, but ventral adhesions were seen between the spinal cord and the dura. Microsurgical intradural exploration revealed ventrolateral herniation of the cord and a ventral root through a dural defect into an epidural arachnoid cyst. The adhesions were released, the cord was repositioned intradurally, and the dural defect was patched. The patients showed gradual improvement postsurgery, as did most of the patients in the previously reported cases. The CSF flow and endoscopic studies were found to be particularly informative, and dural patching with surgical membrane is recommended.
Complications during anterior surgery of the lumbar spine: an anatomically based study and review
Authors: Samudrala Srinath , Khoo Larry T. , Rhim Seung C. , Fessler Richard G.
Published: January 2008

Procedures involving anterior surgical decompression and fusion are being performed with increasing frequency for the treatment of a variety of pathological processes of the spine including trauma, deformity, infection, degenerative disease, failed-back syndrome, discogenic pain, metastases, and primary spinal neoplasms. Because these operations involve anatomy that is often unfamiliar to many neurological and orthopedic surgeons, a significant proportion of the associated complications are not related to the actual decompressive or fusion procedure but instead to the actual exposure itself. To understand the nature of these injuries, a detailed anatomical study and dissection was undertaken in six cadaveric specimens. Critical structures at risk in the abdomen and retroperitoneum were identified, and their anatomical relationships were categorized and photographed. These structures included the psoas muscle, kidneys, ureters, diaphragm and crura, esophageal hiatus, thoracic duct, greater splanchnic nerves, phrenic nerves, sympathetic chains, medial arcuate ligament, superior and inferior hypogastric plexus, segmental and radicular vertebral vessels, aorta, vena cava, median sacral artery, common iliac vessels, iliolumbar veins, lumbosacral plexus, and presacral hypogastric plexus. Based on these dissections and an extensive review of the literature, the authors provide a detailed anatomically based discussion of the complications associated with anterior lumbar surgery.
The Magnetic Resonance Angiography in Relatives of Patients With Subarachnoid Hemorrhage Study Group
Authors: Couldwell William T.
Published: January 2008

Background: The first-degree relatives of patients who have subarachnoid hemorrhage from ruptured intracranial aneurysms are themselves at risk for subarachnoid hemorrhage. We studied the benefits and risks of screening for aneurysms in the first-degree relatives of patients with sporadic subarachnoid hemorrhage. Methods: We screened 626 first-degree relatives (parents, siblings, or children) of 160 patients with sporadic subarachnoid hemorrhage, from a prospective series of 193 consecutive index patients. Magnetic resonance angiography was the screening tool, and conventional angiography was used as the reference test in subjects thought to have aneurysms. Six months after elective operation, outcome was assessed by means of the modified Rankin scale of neurologic function. This observational study design was combined with a decision-analysis model to estimate the effectiveness of screening. The efficiency of screening was defined by the number of relatives who needed to be screened in order to prevent one subarachnoid hemorrhage. Results: Aneurysms were found in 25 of 626 first-degree relatives (4.0 percent; 95 percent confidence interval, 2.6 to 5.8 percent). Eighteen underwent surgery, which resulted in a decrease in function in 11 (disabling in 1). Five had medium-sized aneurysms that were 5 to 11 mm in diameter, 11 had small aneurysms that were less than 5 mm, and 2 had both small and medium-sized aneurysms. On average, surgery increased estimated life expectancy by 2.5 years for these 18 subjects (or by 0.9 month per person screened), at the expense of 19 years of decreased function per person. The number of relatives who would need to be screened in order to prevent 1 subarachnoid hemorrhage on a lifetime basis was 149, and 298 would have to be screened in order to prevent 1 fatal subarachnoid hemorrhage. Conclusions: Implementation of a screening program for the first-degree relatives of patients with sporadic subarachnoid hemorrhage does not seem warranted at this time, since the resulting slight increase in life expectancy does not offset the risk of postoperative sequelae.
Posterior fusion and implantation of the SOCON-SRI system in the treatment of adult spondylolisthesis
Authors: La Rosa Giovanni , Germanò Antonino , Conti Alfredo , Cacciola Fabio , Caruso Gerardo , Tomasello Francesco
Published: January 2008

Surgery for adult patients with lumbar and lumbosacral spondylolisthesis is reserved for those with intractable radiculopathy, claudication, or symptomatic spinal instability. Internal fixation, in which posterior fusion, transpedicular screw fixation, and implantation of titanium devices are performed, has been advocated to improve fusion rates and clinical results. Fourteen consecutive patients with Grade II to III lumbar and lumbosacral spondylolisthesis who underwent posterior decompression, reduction, autologous posterior facet joint arthrodesis, and SOCON-SRI implantation are retrospectively reviewed.

All patients underwent complete preoperative clinical and neuroradiological evaluation. Treatment consisted of posterior decompressive surgery and implantation of the SOCON-SRI system (transpedicular screws, prebent longitudinal rods, and one locking-screw clamps). Distraction of the interbody space and rotation were performed to achieve an optimum spinal realignment. The facet joints were fused by using autologous bone graft. The authors obtained detailed clinical, functional, economic, and neuroradiological follow-up data for up to 14 months (range 8–18 months).

The efficacy of the treatment was evaluated by comparing pre- and postoperative data. Pain was decreased in all cases, neurological dysfunction ameliorated in 50%, and functional and economic status was improved in 78% and 100%, respectively. No cases of fusion failure or instrumentation-related complications occurred. The authors describe their results of treating patients with spondylolisthesis in the light of the rationale for surgery and the more recent pertinent literature.
Lumbosacral junction fixation and fusion after complete L-5 spondylectomy
Authors: Detwiler Paul W. , Porter Randall W. , Crawford Neil R. , Apostolides Paul J. , Dickman Curtis A.
Published: January 2008

The goals of surgery for metastatic disease of the lumbosacral spine are to relieve compression of the thecal sac and nerve roots, to resect malignant tissue, and to create a stable reconstruction of the spine. Reconstruction of the lumbosacral junction, specifically the L-5 vertebral body, is particularly challenging because the biomechanical properties of this level differ from other areas of the spine.

A 40-year-old woman with intraductal breast carcinoma that metastasized to the L-5 vertebral body presented with progressive low-back pain, right-sided L-5 radiculopathy, and weakness. Magnetic resonance imaging revealed a pathological fracture of the L-5 vertebral body with compression of the cauda equina. The L-5 posterior arch, both facet joints and pedicles, and the posterior third of the vertebral body were removed via a posterior approach. A pedicle screw fixation system was applied from L-4 to S-1. The patient was repositioned, and a transabdominal approach was used to resect the anterior two thirds of the L-5 body, which was reconstructed using an allograft bone strut. An interference bone screw was placed through the inferior aspect of the allograft and screwed into the body of S-1 to provide stability for the reconstructive graft.

The patient's clinical recovery was excellent. She was ambulating without difficulty when seen at 19-month follow-up examination.

Complete spondylectomy by using this novel fusion technique was efficacious in the treatment of metastatic disease to the vertebral column.
Stabilizing effect of posterior lumbar interbody fusion cages before and after cyclic loading
Authors: Kettler Annette , Wilke Hans-Joachim , Dietl Rupert , Krammer Matthias , Lumenta Christianto , Claes Lutz
Published: January 2008

The function of interbody fusion cages is to stabilize spinal segments primarily by distracting them as well as by allowing bone ingrowth and fusion. An important condition for efficient formation of bone tissue is achieving adequate spinal stability. However, the initial stability may be reduced due to repeated movements of the spine during everyday activity. Therefore, in addition to immediate stability, stability after cyclic loading is of remarkable relevance; however, this has not yet been investigated. The object of this study was to investigate the immediate stabilizing effect of three different posterior lumbar interbody fusion cages and to clarify the effect of cyclic loading on the stabilization.

Before and directly after implantation of a Zientek, Stryker, or Ray posterior lumbar interbody fusion cage, 24 lumbar spine segment specimens were each evaluated in a spine tester. Pure lateral bending, flexion-extension, and axial rotation moments (± 7.5 Nm) were applied continuously. The motion in each specimen was measured simultaneously. The specimens were then loaded cyclically (40,000 cycles, 5 Hz) with an axial compression force ranging from 200 to 1000 N. Finally, they were tested once again in the spine tester.

In general, a decrease of movement in all loading directions was noted after insertion of the Zientek and Ray cages and an increase of movement after implantation of a Stryker cage. In all three cage groups greater stability was demonstrated in lateral bending and flexion than in extension and axial rotation. Reduced stability during cyclic loading was observed in all three cage groups; however, loss of stability was most pronounced when the Ray cage was used.
Do women fare worse? A metaanalysis of gender differences in outcome after traumatic brain injury
Authors: Farace Elana , Alves Wayne M.
Published: January 2008

The purpose of this metaanalysis was to investigate possible gender differences in TBI sequelae. The case fatality rates in patients after TBI have previously been shown to be significantly higher in women as compared with men. A quantitative review of published studies of TBI outcome revealed eight studies (20 outcome variables) of TBI in which outcome was reported separately for men and women. Outcome was worse in women than in men for 85% of the measured variables, with an average effect size of −0.15. Although clinical opinion is often that women tend to experience better outcomes than do men after TBI, the opposite pattern was suggested in the results of this metaanalysis. However, this conclusion is limited by the fact that in only a small percentage of the total published reports on TBI outcome was outcome described separately for each sex. A careful, prospective study of sex differences in TBI outcome is clearly needed.
Outcome prediction following penetrating craniocerebral injury in a civilian population: aggressive surgical management in patients with admission Glasgow Coma Scale scores of 6 to 15
Authors: Levy Michael L.
Published: January 2008

In an attempt to assess admission Glasgow Coma Scale (GCS) scores and other radiographic variables after penetrating craniocerebral injury in relationship to outcome, the author evaluated a series of 294 patients with penetrating injuries who presented with a GCS score of 6 to 15 over a 6-year period. Entrance criteria required a replicable neurological examination that was not altered by the presence of hypotension, drugs/toxins, or systemic injury. All patients underwent surgical intervention and aggressive perioperative management, including resuscitative protocols, in the neurosurgical intensive care unit.

The author previously devised prospective models of outcome remained unchanged in this series. The variables most predictive of death include admission GCS score and subarachnoid hemorrhage in one model and admission GCS score and pupillary changes in a second when pupillary response was definitive at admission (p ≤ 0.00005). Other important variables related to morbidity include admission GCS, bihemispheric injury when associated with intraventricular hemorrhage, and diffuse fragmentation (p ≤ 0.001).

In this study a significant relationship between operative intervention and survival (p ≤ 0.01) was found in patients with an admission GCS scores of 6 to 8. No significant relationships between operative intervention and survival were found in patients with admission GCS scores of 9 to 12 and 13 to 15. A significant relationship between operative intervention and morbidity (p ≤ 0.01) was also demonstrated in patients with an admission GCS score of 12 to 15. No significant relationships between operative intervention and morbidity were found in patients with an admission GCS score of 6 to 8 and 9 to 12.
Activation of the anterior cingulate cortex by thalamic stimulation in patients with chronic pain: a positron emission tomography study
Authors: Davis Karen D. , Taub Ethan , Duffner Frank , Lozano Andres M. , Tasker Ronald R. , Houle Sylvain , Dostrovsky Jonathan O.
Published: January 2008

Object

Deep brain stimulation (DBS) of the sensory thalamus has been used to treat chronic, intractable pain. The goal of this study was to investigate the thalamocortical pathways activated during thalamic DBS.

Methods

The authors compared positron emission tomography (PET) images obtained before, during, and after DBS in five patients with chronic pain. Two of the five patients reported significant DBS-induced pain relief during PET scanning, and the remaining three patients did not report any analgesic effect of DBS during scanning. The most robust effect associated with DBS was activation of the anterior cingulate cortex (ACC). An anterior ACC activation was sustained throughout the 40 minutes of DBS, whereas a more posteriorly located ACC activation occurred at a delay after onset of DBS, although these activations were not dependent on the degree of pain relief reported during DBS. However, implications specific to the analgesic effect of DBS require further study of a larger, more homogeneous patient population. Additional effects of thalamic DBS were detected in motor-related regions (the globus pallidus, cortical area 4, and the cerebellum) and visual and association cortical areas.

Conclusions

The authors demonstrate that the ACC is activated during thalamic DBS in patients with chronic pain.
A positron emission tomography study of cerebrovascular reserve before and after shunt surgery in patients with idiopathic chronic hydrocephalus
Authors: Klinge Petra M. , Berding Georg , Brinker Thomas , Knapp Wolfram H. , Samii Madjid
Published: January 2008

Object

In this study the authors use positron emission tomography (PET) to investigate cerebral blood flow (CBF) and cerebrovascular reserve (CVR) in chronic hydrocephalus.

Methods

Ten patients whose mean age was 67 ± 10 years (mean ± standard deviation [SD]) were compared with 10 healthy volunteers who were 25 ±3 years of age. Global CBF and CVR were determined using 15O–H2O and PET prior to shunt placement and 7 days and 7 months thereafter. The CVR was measured using 1 g acetazolamide. Neurological status was assessed based on a score assigned according to the methods of Stein and Langfitt.

Seven months after shunt placement, five patients showed clinical improvement (Group A) and five did not (Group B). The average global CBF before shunt deployment was significantly reduced in comparison with the control group (40 ± 8 compared with 61 ± 7 ml/100 ml/minute; mean ± SD, p < 0.01). In Group A the CBF values were significantly lower than in Group B (36 ± 7 compared with 44 ± 8 ml/100 ml/minute; p < 0.05). The CVR before surgery, however, was not significantly different between groups (Group A = 43 ± 21%, Group B = 37 ± 29%). After shunt placement, there was an increase in the CVR in Group A to 52 ± 37% after 7 days and to 68 ± 47% after 7 months (p < 0.05), whereas in Group B the CVR decreased to 14 ± 18% (p < 0.05) after 7 days and returned to the preoperative level (39 ± 6%) 7 months after shunt placement.

Conclusions

The preliminary results indicate that a reduced baseline CBF before surgery does not indicate a poor prognosis. Baseline CBF before shunt placement and preoperative CVR are not predictive of clinical outcome. A decrease in the CVR early after shunt placement, however, is related to poor late clinical outcome, whereas early improvement in the CVR after shunt placement indicates a good prognosis.
Pain and syringomyelia: a review
Authors: Todor D. Roxanne , Mu Harrison T. M. , Milhorat Thomas H.
Published: January 2008

The pathophysiological basis of chronic pain syndromes remains poorly defined. Central and dysesthetic pain are probably the most disabling of sensory disturbances associated with syringomyelia, and, unfortunately, effective treatment remains elusive. In this paper, the authors review their institutional experience with both clinical and laboratory studies of patients with syringomyelia, and they review the relevant literature. To date, there is no consensus as to the best treatment for central cord pain syndromes, although there are many promising areas of current research involving the use of neurochemicals in the spinal cord.
Hypoxia-inducible expression of BAX: application in tumor-targeted gene therapy
Authors: Ruan Hangjun , Hu Lily , Wang Jingli , Ozawa Tomoko , Sanai Nader , Zhang Michael , Lamborn Kathleen R. , Deen Dennis F.
Published: January 2008

Object

The presence of hypoxic cells in human brain tumors contributes to the resistance of these tumors to radiation therapy. However, because normal tissues are not hypoxic, the presence of hypoxic cells also provides the potential for designing cancer-specific gene therapy. Suicide genes can be expressed specifically in hypoxic conditions by hypoxia-responsive elements (HREs), which are activated through the transcriptional complex hypoxia-inducible factor–1 (HIF-1).

Methods

The authors have transfected the murine BAX–green fluorescent protein (GFP) fusion gene under the regulation of three copies of HRE into U-87 MG and U-251 MG cells and selected stably transfected clones. Even though BAX was expressed under both oxic and anoxic conditions in these clones, cell survival assays demonstrated increased cell killing under anoxic as compared with oxic conditions. Cells obtained from most of these clones did not grow in vivo, or the tumors exhibited highly variable growth rates. However, cells obtained from the U-251 MG clone A produced tumors that grew as well as tumors derived from parental cells, and examination of the tumor sections under fluorescent microscopy revealed GFP expression in localized regions. Western blot analyses confirmed an increased BAX expression in these tumors. Analysis of the results suggests that HRE-regulated BAX can be a promising tool to target hypoxic brain tumor cells. However, there are measurable levels of BAX-GFP expression in this three-copy HRE–mediated expression system under oxia, suggesting promoter leakage. In addition, most clones did not show significant induction of BAX-GFP under anoxia. Therefore, the parameters of this HRE-mediated expression system, including HRE copy number and the basal promoter, need to be optimized to produce preferential and predictable gene expression in hypoxic cells.
Update on therapies for acute ischemic stroke
Authors: Kindler Dean D. , Lopez George A. , Worrall Bradford B. , Johnston Karen C.
Published: January 2008

Acute ischemic stroke is now considered a neurological emergency for which there are new therapies. Neurosurgeons and neurologists need to remain apprised of advances in this field. The authors discuss approved and emerging therapies for patients suffering from acute ischemic stroke, based on a review of recent publications. Currently, intravenous tissue-type plasminogen activator is the only Food and Drug Administration–approved therapy for acute ischemic stroke. Intraarterial delivery of thrombolytics is a promising treatment and may be effective in selected patients. Other therapies for acute cerebral ischemia are intriguing but still in the investigational stages.
Direct anterior screw fixation for recent and remote odontoid fractures
Authors: Apfelbaum Ronald I. , Lonser Russell R. , Veres Robert , Casey Adrian
Published: January 2008

Object

The management of odontoid fractures remains controversial. Only direct anterior screw fixation provides immediate stabilization of the spine and may preserve normal C1–2 motion. To determine the indications, optimum timing, and results for direct anterior screw fixation of odontoid fractures, the authors reviewed the surgery-related outcome of patients who underwent this procedure at two institutions.

Methods

One hundred forty-seven consecutive patients (98 males and 49 females) who underwent direct anterior screw fixation for a recent fracture (< 6 months postinjury [129 patients]) or remote (≥ 18 months postinjury [18 patients]) Type II (138 cases) or III (nine cases) odontoid fractures at the University of Utah (94 patients) and National Institute of Traumatology in Budapest, Hungary (53 patients) between 1986 and 1998 are included in this study (mean follow-up period 18.2 months). Data obtained from clinical examination, review of hospital charts, operative findings, and imaging studies were used to analyze the surgery-related results in these patients.

In patients with recent fractures there was an overall bone fusion rate of 88%. The rate of anatomical bone fusion of recent fractures was significantly (p ≤ 0.05) higher in fractures oriented in the horizontal and posterior oblique direction (as compared with anterior oblique), but this finding was independent (p ≥ 0.05) of age, sex, number of screws placed (one or two), and the degree or the direction of odontoid displacement. In patients with remote fractures there was a significantly lower rate of bone fusion (25%). Overall, complications related to hardware failure occurred in 14 patients (10%) and unrelated to hardware in three patients (2%). There was one death (1%) related to surgery.

Conclusions

Direct anterior screw fixation is an effective and safe method for treating recent odontoid fractures (< 6 months postinjury). It confers immediate stability, preserves C1–2 rotatory motion, and achieves a fusion rate that compares favorably with alternative treatment methods. In contradistinction, in patients with remote fractures (≥ 18 months postinjury) a significantly lower rate of fusion is found when using this technique, and these patients are believed to be poor candidates for this procedure.
Management of acute odontoid fractures: operative techniques and complication avoidance
Authors: SK Shushil Shilpakar , McLaughlin Mark R. , Haid Regis W. , Rodts Gerald E. , Subach Brian R.
Published: January 2008

In this article the authors describe the management of Type II odontoid fractures with special attention to operative technique and avoidance of complication. Anterior odontoid screw fixation is a procedure the authors have performed over the last 8 years in cases with acute Type II and rostral Type III odontoid fractures. In cases of Chronic Type II odontoid fractures and in patients with transverse ligament disruption, the authors prefer to undertake posterior transarticular facet screw fixation supplemented by bone graft and interspinous C1–2 wiring.

The technical aspects of these procedures are described with a focus on operative nuances. Selection criteria and techniques that the authors have refined over the years have helped them to optimize success rates and minimize complications.
Persistent posttraumatic cerebrospinal fluid leakage
Authors: Friedman Jonathan A. , Ebersold Michael J. , Quast Lynn M.
Published: January 2008

Object

Persistent posttraumatic cerebrospinal fluid (CSF) leakage frequently complicates skull base fractures. Although many CSF leaks will cease without treatment, patients with CSF leaks that persist greater than 24 hours may be at increased risk for meningitis, and many will require surgical intervention. The authors reviewed their 15-year experience with posttraumatic CSF leaks that persisted longer than 24 hours.

Methods

The authors reviewed the medical records of 51 patients treated between 1984 and 1998 with CSF leaks that persisted for 24 hours or longer after traumatic head injury. In 27 patients (55%) spontaneous resolution of CSF leakage occurred at an average of 5 days posttrauma. In 23 patients (45%) surgery was required to resolve the leakage. Eight patients (16%) with occult CSF leaks presented with recurrent meningitis at an average of 6.5 years post-trauma. Forty-three (84%) patients with CSF leaks sustained a skull fracture, most commonly involving the frontal sinus, whereas parenchymal brain injury or extraaxial hematoma was demonstrated in only 18 patients (35%). Delayed CSF leaks, with an average onset of 13 days posttrauma, were observed in eight patients (16%).

Among patients with clinically evident CSF leakage, the frequency of meningitis was 10% with antibiotic prophylaxis, and 21% without antibiotic prophylaxis. Thus, prophylactic antibiotic administration halved the risk of meningitis. A variety of surgical approaches was used, and no significant neurological morbidity occurred. Three (13%) of 23 surgically treated patients required additional surgery to treat continued CSF leakage.

Conclusions

A significant proportion of patients with CSF leaks that persist greater than 24 hours will require surgical intervention. Prophylactic antibiotic therapy may be effective in this group of patients. Patients with skull base or frontal sinus fractures should be followed to detect the occurrence of delayed leakage. Surgery-related outcome is excellent.
Diagnosis and management of posttraumatic oculorrhea
Authors: Salame Khalil , Segev Yoram , Fliss Dan M. , Ouaknine Georges E.
Published: January 2008

Posttraumatic cranio-orbital cerebrospinal fluid (CSF) fistula is very rare. Diagnosis of these fistulas may be difficult, and it is possible that this complication of craniofacial injury is underdiagnosed. Early recognition and adequate treatment is of paramount importance to prevent hazardous complications. The authors report the case of a 20-year-old woman in whom a CSF leak developed through the medial canthus area of her eye after she sustained a mild sports-related injury. Clinical examination and chemical analysis of the fluid led to the correct diagnosis, and the leak was stopped with conservative treatment. It is proposed that a CSF leak through the eye be termed “oculorrhea” as compared with otorrhea and rhinorrhea. The mechanism of the fistula in this patient is discussed, as is the pertinent radiologically demonstrated anatomy and the mechanism of injury. Management and controversies are also discussed.