the dens fracture. Horizontal fractures of the atlas not associated with dens fractures have been regarded as stable injuries that cause no neurological deficits, and they have been treated successfully with the placement of a cervical collar only. 5 , 9 , 11 , 13 , 15 To our knowledge, horizontal fractures of the C-1 anterior arch in association with unstable ligamentous injuries of the craniocervical junction have yet to be reported. In the present study we report on 5 cases of C-1 horizontal fractures associated with severe distraction injuries of the
Marcelo D. Vilela, Richard J. Bransford, Carlo Bellabarba and Richard G. Ellenbogen
Richard G. Ellenbogen, Rocco A. Armonda, Dennis W. W. Shaw and H. Richard Winn
In patients with Chiari I malformation with and without associated syringomyelia, aberrant cerebrospinal fluid (CSF) dynamics and a spectrum of posterior fossa pathological findings are demonstrated. In this study, the authors test the validity of using prospective cardiac-gated phase-contrast cine-mode magnetic resonance (MR) imaging to define the malformation, delineate its pathophysiology, and assist in implementing a rational treatment plan.
Eighty-five cases were prospectively analyzed using cine MR imaging. Sixty-five patients, adults and children, with symptomatic Chiari malformation, with and without syringomyelia, were surgically treated from 1990 to 1999. All patients underwent pre- and postoperative cine MR evaluation. Ten patients were treated after a previous surgical procedure had failed. To establish CSF flow characteristics and normative CSF profiles, 20 healthy volunteers were examined.
Compared with normal volunteers, in Chiari I malformation patients with and without syringomyelia, uniformly abnormal craniocervical junction CSF flow profiles were revealed. After intradural exploration, nearly all patients with Chiari I malformation experienced clinical improvement and CSF flow profiles, paralleling those of normal volunteers, were shown. In all patients in whom treatment had failed, abnormal preoperative CSF flow profiles, which correlated with suspected physiological abnormalities and the pathological findings noted at reoperation, were demonstrated.
Symptomatic Chiari I malformation is a dynamic process characterized by the impaction of the hindbrain in an abnormal posterior fossa. This compression obstructs the normal venting of CSF in and out of the craniocervical sub-arachnoid space, throughout the cardiac cycle. Therefore, decompression or enlargement of the posterior fossa to establish normal CSF pathways should be the primary goal of surgical intervention. Aberrant CSF flow appears to be only one aspect of the pathological condition found in patients with Chiari I malformation. Arachnoid scarring in the posterior fossa and selective vulnerability of the spinal cord may also be factors in the pathogenesis and maintenance of associated syringomyelia. Phase-contrast cine MR imaging is a useful tool in defining physiological and anatomical problems in patients with Chiari I and syringomyelia, and it can help guide an appropriate primary or salvage surgical therapy.
Ali H. Mesiwala, Christopher I. Shaffrey, Joseph S. Gruss and Richard G. Ellenbogen
zygomatic arch. B: Inferior view of a 3D CT reconstruction of cranium and cervical spine. Several defects of the posterior fossa cranium are seen (black arrows) , as well as the defects of the left middle cranial fossa and left mandibular condyle (white arrow) . C and D: Coronal T 2 -weighted MR images of the head. C: Coronal reconstruction of the craniocervical junction demonstrating hypoplasia of the left occipital condyle and left arch of C-1 (black arrow) , assimilation of the right lateral mass of C-1 with the right occipital condyle (white arrow) , and
Michael R. Levitt, Toba N. Niazi, Richard A. Hopper, Richard G. Ellenbogen and Jeffrey G. Ojemann
orbits ( Fig. 1 ). The posterior fossa appeared crowded, and subsequent MR imaging of the brain demonstrated a CM-I with 11 mm of inferior herniation of the cerebellar tonsils ( Fig. 2A ) and markedly diminished CSF flow at the craniocervical junction ( Video 1 , panel A). V ideo 1. Clips showing pre- and postoperative CSF flow on MR imaging studies. Preoperative sagittal cine-sequence MR imaging (A) demonstrates marked constriction of CSF flow at the ventral brainstem (arrow). Significant improvement in flow ventral to the brainstem (arrow) is seen on
Report of three cases
Saadi Ghatan, David W. Newell, M. Sean Grady, Sohail K. Mirza, Jens R. Chapman, Frederick A. Mann and Richard G. Ellenbogen
✓ Children younger than 3 years of age represent a distinct subpopulation of patients at particular risk for high cervical and craniovertebral injuries. There are few descriptions of survivors of severe craniocervical trauma among the very young, and scarce data exist regarding management after initial emergency stabilization.
The authors describe three children, age 1 to 32 months, who presented with craniocervical junction injuries. Variable neurological findings were observed at presentation (cranial nerve deficits, obtundation, and moderate-to-severe quadriparesis). All three were treated with prolonged immobilization and have recovered with minimal to no neurological deficit.