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Eric M. Horn, Ruth E. Bristol, Iman Feiz-Erfan, Elisa J. Beres, Nicholas C. Bambakidis and Nicholas Theodore

✓Pseudomeningoceles rarely develop after cervical trauma; in all reported cases the lesions have extended outside the spinal canal.

The authors report the first known cases of anterior cervical pseudomeningoceles contained entirely within the spinal canal and causing cord compression and neurological injury. The authors retrospectively reviewed the cases of three patients with traumatic cervical spine injuries and concomitant compressive anterior pseudomeningoceles. The lesion was recognized in the first case when the patient’s neurological status declined after he sustained a severe atlantoaxial injury; the pseudomeningocele was identified intraoperatively and decompressed. After the decompressive surgery, the patient’s severe tetraparesis partially resolved. In the other two patients diagnoses of similar pseudomeningoceles were established by magnetic resonance imaging. Both patients were treated conservatively, and their mild to moderate hemiparesis due to the pseudomeningocele-induced compression abated.

The high incidence of anterior cervical pseudomeningoceles seen at the authors’ institution within a relatively brief period suggests that this lesion is not rare. The authors believe that it is important to recognize the compressive nature of these lesions and their potential to cause devastating neurological injury.

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Eric M. Horn, Jonathan S. Hott, Randall W. Porter, Nicholas Theodore, Stephen M. Papadopoulos and Volker K. H. Sonntag

✓ Atlantoaxial stabilization has evolved from simple posterior wiring to transarticular screw fixation. In some patients, however, the course of the vertebral artery (VA) through the axis varies, and therefore transarticular screw placement is not always feasible. For these patients, the authors have developed a novel method of atlantoaxial stabilization that does not require axial screws. In this paper, they describe the use of this technique in the first 10 cases.

Ten consecutive patients underwent the combined C1–3 lateral mass–sublaminar axis cable fixation technique. The mean age of the patients was 62.6 years (range 23–84 years). There were six men and four women. Eight patients were treated after traumatic atlantoaxial instability developed (four had remote trauma and previous nonunion), whereas in the other two atlantoaxial instability was caused by arthritic degeneration. All had VA anatomy unsuitable to traditional transarticular screw fixation.

There were no intraoperative complications in any of the patients. Postoperative computed tomography studies demonstrated excellent screw positioning in each patient. Nine patients were treated postoperatively with the aid of a rigid cervical orthosis. The remaining patient was treated using a halo fixation device. One patient died of respiratory failure 2 months after surgery. Follow-up data (mean follow-up duration 13.1 months) were available for seven of the remaining nine patients and demonstrated a stable construct with fusion in each patient.

The authors present an effective alternative method in which C1–3 lateral mass screw fixation is used to treat patients with unfavorable anatomy for atlantoaxial transarticular screw fixation. In this series of 10 patients, the method was a safe and effective way to provide stabilization in these anatomically difficult patients.

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Eric M. Horn, Nicholas Theodore, Iman Feiz-Erfan, Gregory P. Lekovic, Curtis A. Dickman and Volker K. H. Sonntag


The risk factors of halo fixation in elderly patients have never been analyzed. The authors therefore retrospectively reviewed data obtained in the treatment of such cases.


A discharge database was searched for patients 70 years of age or older who had undergone placement of a halo device. In a search of cases managed between April 1999 and February 2005, data pertaining to 53 patients (mean age 79.9 years [range 70–97 years]) met these criteria. Forty-one patients were treated for traumatic injuries. Ten patients had deficits ranging from radiculopathy to quadriparesis, and 43 had no neurological deficit. Adequate follow-up material was available in 42 patients (mean treatment duration 91 days). Halo immobilization was the only treatment in 21 patients, and adjunctive surgical fixation was undertaken in the other 21 patients. There were 31 complications in 22 patients: respiratory distress in four patients, dysphagia in six, and pin-related complications in 10. Eight patients died; in two of these cases, the cause of death was clearly unrelated to the halo brace. The other six patients died of respiratory failure and cardiovascular collapse (perioperative mortality rate 14%). Three patients who died had sustained acute trauma and three had undergone surgical stabilization.


External halo fixation can be used safely to treat cervical instability in elderly patients. The high complication rate in this population may reflect the significant incidence of underlying disease processes.

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Rudolf Ludwig Karl Virchow: pathologist, physician, anthropologist, and politician

Implications of his work for the understanding of cerebrovascular pathology and stroke

Sam Safavi-Abbasi, Cassius Reis, Melanie C. Talley, Nicholas Theodore, Peter Nakaji, Robert F. Spetzler and Mark C. Preul

✓ The history of apoplexy and descriptions of stroke symptoms date back to ancient times. It was not until the mid-nineteenth century, however, that the contributions of Rudolf Ludwig Karl Virchow, including his descriptions of the phenomena he called “embolism” and “thrombosis” as well as the origins of ischemia, changed the understanding of stroke. He suggested three main factors that conduce to venous thrombosis, which are now known as the Virchow triad. He also showed that portions of what he called a “thrombus” could detach and form an “embolus.” Thus, Virchow coined these terms to describe the pathogenesis of the disorder. It was also not until 1863 that Virchow recognized and differentiated almost all of the common types of intracranial malformations: telangiectatic venous malformations, arterial malformations, arteriovenous malformations, cystic angiomas (possibly what are now called hemangioblastomas), and transitional types of these lesions. This article is a review of the contributions of Rudolf Virchow to the current understanding of cerebrovascular pathology, and a summary of the life of this extraordinary personality in his many roles as physician, pathologist, anthropologist, ethnologist, and politician.

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Seref Dogan, Sam Safavi-Abbasi, Nicholas Theodore, Eric Horn, Harold L. Rekate and Volker K. H. Sonntag


In this study the authors evaluated the mechanisms and patterns of injury and the factors affecting management and outcome of pediatric subaxial cervical spine injuries (C3–7).


Fifty-one pediatric patients (38 boys and 13 girls; mean age 12.4 years, range 10 months–16 years) with subaxial cervical spine injuries were reviewed retrospectively. Motor vehicle accidents (MVAs) were the most common cause of injury. Overall, 12% presented with a dislocation, 63% with a fracture, 19% with a fracture–dislocation, and 6% with a ligamentous injury. The most frequently injured level was C6–7 (33%); C3–4 (6%) was least frequently involved. Sixty-four percent of patients were neurologically intact, 16% had incomplete spinal cord injuries (SCIs), 14% had complete SCIs, and three patients (6%) died after admission and before assessment. Treatment was conservative in 64%: seven (13%) wore a halo vest and 26 (51%) wore a rigid cervical orthosis. Surgery was performed in the other 18 patients (36%), with the breakdown as follows: 15 (30%) underwent an anterior approach, two (4%) had posterior approaches, and one (2%) had a combined approach. Postoperatively, four patients (8%) who had a neurological deficit improved. The overall mortality rate was 8%; all deaths were related to MVAs. There were no surgery-related deaths or complications.


Subaxial cervical spine injuries are common in children 9 to 16 years of age, and occur principally between C-5 and C-7. Multilevel injury is more common in children 8 years of age and older than in younger children and infants. Most patients with subaxial cervical spine injuries can be treated conservatively. Both anterior and posterior approaches are safe and effective.

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Skeletal dysplasia involving the subaxial cervical spine

Report of two cases and review of the literature

Gregory P. Lekovic, Nitin R. Mariwalla, Eric M. Horn, Steven Chang, Harold L. Rekate and Nicholas Theodore

✓ Because skeletal dysplasias are primary disorders of bone, they have not been commonly understood as neurosurgical diseases. Nevertheless, neurosurgical complications are commonly encountered in many cases of dysplasia syndromes. The authors present two cases of skeletal dysplasia that caused overt instability of the cervical spine. One patient with a diagnosis of Gorham disease of the cervical spine was treated with prolonged fixation in a halo brace after an initial attempt at instrumentation with a posterior occiput–C4 fusion. The other patient, who at birth was identified to have camptomelic dysplasia, has been treated conservatively from the outset. Although these two patients presented with different disorders—in one patient adequate mature bone never formed and in the other patient progressive bone loss became apparent after a seemingly normal initial development—these cases demonstrate unequivocally that surgical options for fusion are ultimately limited by the quality of the underlying bone. In patients in whom the bone itself is inadequate for use as a substrate for fusion, there are currently limited treatment options. Future improvements in our understanding of chondrogenesis and ossification may lead to the design of superior methods of encouraging fusion in these patients; however, at the present time, long-term maintenance in a halo brace may, in fact, be the only treatment.

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Nicholas Theodore and Harold L. Rekate

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Nicholas C. Bambakidis, Nicholas Theodore, Peter Nakaji, Adrian Harvey, Volker K. H. Sonntag, Mark C. Preul and Robert H. Miller

The continuous regeneration of glial cells arising from endogenous stem cell populations in the central nervous system (CNS) occurs throughout life in mammals. In the ongoing research to apply stem cell therapy to neurological diseases, the capacity to harness the multipotential ability of endogenous stem cell populations has become apparent. Such cell populations proliferate in response to a variety of injury states in the CNS, but in the absence of a supportive microenvironment they contribute little to any significant behavioral recovery. In the authors' laboratory and elsewhere, recent research on the regenerative potential of these stem cells in disease states such as spinal cord injury has demonstrated that the cells' proliferative potential may be greatly upregulated in response to appropriate growth signals and exogenously applied trophic factors. Further understanding of the potential of such multipotent cells and the mechanisms responsible for creating a favorable microenvironment for them may lead to additional therapeutic alternatives in the setting of neurological diseases. These therapies would require no exogenous stem cell sources and thus would avoid the ethical and moral considerations regarding their use. In this review the authors provide a brief overview of the enhancement of endogenous stem cell proliferation following neurological insult.

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Cervical magnetic resonance imaging abnormalities not predictive of cervical spine instability in traumatically injured patients

Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004

Eric M. Horn, Gregory P. Lekovic, Iman Feiz-Erfan, Volker K. H. Sonntag and Nicholas Theodore

Object. Identifying instability of the cervical spine can be difficult in traumatically injured patients. The goal of this study was to determine whether cervical abnormalities demonstrated on magnetic resonance (MR) imaging are predictive of spinal instability.

Methods. Data in all patients admitted through the Level I trauma service at the authors' institution who had undergone cervical MR imaging were retrospectively reviewed. The reasons for MR imaging screening were neurological deficit, fracture, neck pain, and indeterminate clinical examination (for example, coma). Abnormal soft-tissue (prevertebral or paraspinal) findings on MR imaging were correlated with those revealed on computerized tomography (CT) scanning and plain and dynamic radiography to determine the presence/absence of cervical instability.

Of 6328 patients admitted through the trauma service, 314 underwent MR imaging of the cervical spine. Of 166 patients in whom CT scanning or radiography demonstrated normal findings, 70 had undergone MR imaging that revealed abnormal findings. Of these 70 patients, 23 underwent dynamic imaging, the findings of which were normal. In each case of cervical instability (65 patients) CT, radiographic, and MR imaging studies demonstrated abnormalities. Furthermore, there were 143 patients with abnormal CT or radiographic study findings, in 13 of whom MR imaging revealed normal findings. Six of the latter underwent dynamic testing, which demonstrated normal results.

Conclusions. Magnetic resonance imaging is sensitive to soft-tissue injuries of the cervical spine. When CT scanning and radiography detect no fractures or signs of instability, MR imaging does not help in determining cervical stability and may lead to unnecessary testing when not otherwise indicated.