the primary cause. 3 , 11 Pathological CSF flow at the foramen magnum and cervical spinal canal has been demonstrated by PC-cine MRI studies in patients with CM-I and syringomyelia. 7 , 10 Phase contrast–cine MRI enables analysis of CSF flow patterns and dynamic changes during a cardiac cycle. Research using PC-cine MRI has shown that patients with CM-I have significantly abnormal CSF flow in the spinal subarachnoid space of the craniocervical junction. 2 , 20 Indeed, presenting symptomatology has been defined to correlate with the degree of hindbrain CSF flow
Yingsong Wang, Jingming Xie, Zhi Zhao, Ying Zhang, Tao Li and Yongyu Si
Uwe Max Mauer, Andreas Gottschalk, Ulrich Kunz and Chris Schulz
associated with a wide variety of diseases. Obstruction of CSF flow either at the craniocervical junction or in the spinal subarachnoid space is a factor common to all conditions that cause syringomyelia. 3 The CSF pulsations are a result of the flow of blood into the nervous system, which leads to a volume shift from cranial to spinal spaces and from the extracellular to the subarachnoid space. Syringomyelia is thus not a disease in itself, but a symptom of a wide variety of diseases that are associated with an obstruction of pulsatile CSF flow. Spinal intradural CSF
Taro Kaibara, R. John Hurlbert and Garnette R. Sutherland
T he surgical treatment of anterior upper cervical spine and skull base disease remains challenging because of their anatomical complexity and limited surgical accessibility. The transoral pathway provides a direct and useful route to lesions involving the craniocervical junction. Described in the surgical treatment of a variety of extra- and intradural lesions, 1, 3–7, 11–14, 18–23 including rheumatoid disease, glomus tumors, chordomas, meningiomas, schwannomas, platybasia, fractures, and metastasis, at this location, its popularity has grown as
Tien V. Le, Elias Dakwar, Shannon Hann, Euclides Effio, Ali A. Baaj, Carlos Martinez, Fernando L. Vale and Juan S. Uribe
O ccipitocervical fixation remains a challenge due to the anatomical complexity of the craniocervical junction. Occipital plates are commonly used as the cephalad fixation point in these constructs, but issues such as the need for multiple points of fixation within a limited area, limited surface area for grafting, and potential for intracranial injuries have led to investigations for alternatives. 14 We have recently described a novel surgical technique that is performed using the occipital condyles as the sole cephalad fixation points for
Ibrahim H. Al-Ahmed, Mohamed Boughamoura, Peter Dirks, Abhaya V. Kulkarni, James T. Rutka and James M. Drake
N eurenteric cysts are endodermal or enterogenic cysts that are considered to be rare endotheliumlined structures. 18 They have been classified into 3 types. The simpler forms (Type 1) are thin walled, with a layer of stratified or a pseudostratified cuboidal or columnar epithelium on a basement membrane. More complex varieties are less common and have additional mesodermal elements such as smooth muscle and fat (Type 2) and sometimes also ependymal or glial tissue (Type 3). Neurenteric cysts appear to be exceptionally rare at the craniocervical junction
G. Edward Vates, Kevin C. Wang, David Bonovich, Christopher F. Dowd and Michael T. Lawton
craniocervical junction or external compression of a VA by ligamentous insertions or deep fascia at the scalenovertebral angle, although other structural abnormalities that can compress a VA anywhere along its course have been described. 2 Although osteophytes and other degenerative changes in the cervical spine have been found to cause bow hunter stroke, 1, 5, 9, 11 our case is unique because it is the first in which a case of bow hunter stroke that can, to the best of our knowledge, be linked to a lateral disc herniation in the cervical spine. The anatomy of the
Report of two cases and review of the literature
Gary L. Gallia, Nirit Weiss, James N. Campbell, Edward F. McCarthy, Anthony P. Tufaro and Ziya L. Gokaslan
approach and was removed during the second stage. An occipitocervical fusion was performed using bilateral occipital screws and C-3, C-4, and C-5 lateral mass screws. Morselized cancellous allograft and demineralized bone matrix were used to promote bone fusion. The second stage was performed 2 days later. Following a tracheostomy, the patient underwent a left-sided transmandibular circumglossal approach to the anterior craniocervical junction. 8 After exposure of the anterior clival/C1–2 region, the tumor anterior to the C-1 and C-2 VBs was removed. Because tumor
Wayne M. Gluf and Douglas L. Brockmeyer
Object. In this, the second of two articles regarding C1–2 transarticular screw fixation, the authors discuss their surgical experience in treating patients 16 years of age and younger, detailing the rate of fusion, complication avoidance, and lessons learned in the pediatric population.
Methods. The authors retrospectively reviewed 67 consecutive patients (23 girls and 44 boys) younger than 16 years of age in whom at least one C1–2 transarticular screw fixation procedure was performed. A total of 127 transarticular screws were placed in these 67 patients whose mean age at time of surgery was 9 years (range 1.7–16 years). The indications for surgery were trauma in 24 patients, os odontoideum in 22 patients, and congenital anomaly in 17 patients. Forty-four patients underwent atlantoaxial fusion and 23 patients underwent occipitocervical fusion. Two of the 67 patients underwent halo therapy postoperatively.
All patients were followed for a minimum of 3 months. In all 67 patients successful fusion was achieved.Complications occurred in seven patients (10.4%), including two vertebral artery injuries.
Conclusions. The use of C1–2 transarticular screw fixation, combined with appropriate atlantoaxial and craniovertebral bone/graft constructs, resulted in a 100% fusion rate in a large consecutive series of pediatric patients. The risks of C1–2 transarticular screw fixation can be minimized in this population by undertaking careful patient selection and meticulous preoperative planning.
Russ P. Nockels, Christopher I. Shaffrey, Adam S. Kanter, Syed Azeem and Julie E. York
Instability of the occipitocervical junction may result from degenerative disease, infection, tumor, and trauma. Surgical stabilization involving screw fixation and rigid implants has been found to be biomechanically superior to wire-based implants. To evaluate the long-term results in a large and diverse patient population, the authors prospectively studied a consecutive group of 69 patients.
All patients underwent occipitocervical fusion in which rigid posterior instrumentation included either plates or rods and screws. Patients ranged in age from 11 to 90 years (mean 51.4 years); there were 34 female and 35 male patients. The mean follow-up duration was 37 months (range 6–66 months). Fifty-seven (83%) of the 69 patients had long-standing occipitocervical anomalies, whereas the remainder presented with acute instability. Basilar invagination was present in 20 patients.
Correction of a severe cervical kyphotic deformity was accomplished in six patients. There were no fatalities or medical complications associated with the procedures. During the follow-up period, 87% of the patients exhibited improvement in their myelopathic symptoms; in 13% the symptoms were unchanged. Complications were minimal. Stability was demonstrated on flexion/extension studies in all cases. There were no treatment-related deaths, although four patients died within the follow-up period, all due to progression of metastatic disease.
The authors found that rigid internal fixation of the occipitocervical complex was safe, effective, and technically possible for spine surgeons familiar with occipital bone anatomy and lateral mass fixation.
L. Fernando Gonzalez, Neil R. Crawford, Robert H. Chamberlain, Luis E. Perez Garza, Mark C. Preul, Volker K. H. Sonntag and Curtis A. Dickman
Object. The authors compared the biomechanical stability resulting from the use of a new technique for occipitoatlantal motion segment fixation with an established method and assessed the additional stability provided by combining the two techniques.
Methods. Specimens were loaded using nonconstraining pure moments while recording the three-dimensional angular movement at occiput (Oc)—C1 and C1–2. Specimens were tested intact and after destabilization and fixation as follows: 1) Oc—C1 transarticular screws plus C1–2 transarticular screws; 2) occipitocervical transarticular (OCTA) plate in which C1–2 transarticular screws attach to a loop from Oc to C-2; and (3) OCTA plate plus Oc—C1 transarticular screws.
Occipitoatlantal transarticular screws reduced motion to well within the normal range. The OCTA loop and transarticular screws allowed a very small neutral zone, elastic zone, and range of motion during lateral bending and axial rotation. The transarticular screws, however, were less effective than the OCTA loop in resisting flexion and extension.
Conclusions. Biomechanically, Oc—C1 transarticular screws performed well enough to be considered as an alternative for Oc—C1 fixation, especially when instability at C1–2 is minimal. Techniques for augmenting these screws posteriorly by using a wired bone graft buttress, as is currently undertaken with C1–2 transarticular screws, may be needed for optimal performance.