significance historically ascribed to the apical ligament so that clinicians will know whether to focus on disease or disruption of the ligament when considering the craniocervical junction. Materials and Methods Twenty formalin-fixed adult human cadavers were placed in the prone position, and their apical ligaments dissected. Twelve specimens were from males and eight from females. The age range of the patients from whom the specimens were obtained was from 59 to 87 years of age (mean 73 years). No pathological entities were noted at the craniocervical junction in any
R. Shane Tubbs, Paul Grabb, Alan Spooner, Wally Wilson and W. Jerry Oakes
R. Shane Tubbs, John C. Wellons III, Jason Banks, Jeffrey P. Blount and W. Jerry Oakes
clinicians who appreciate the craniocervical junction as part of their discipline. Materials and Methods Fifty dried adult human C-1 vertebrae were used in this study. Twenty-nine specimens were obtained in male cadavers and 21 in female cadavers. All specimens were obtained in elderly caucasian individuals. Three male specimens were from C-1 vertebrae that had assimilated into the occiput. All dimensions were measured using calipers, and No. 2.5 surgical loupes were used for magnification. Measurements were made on both the left and right tubercles of each vertebra
R. Shane Tubbs, John C. Wellons III, Jeffrey P. Blount, Paul A. Grabb and W. Jerry Oakes
the craniocervical junction does not correlate with the presence of syringomyelia in the Chiari I malformation and that this compression was seemingly due to a posteriorly oriented odontoid, not true basilar invagination. Our present results show that higher grades of odontoid angulation do indeed correlate with syringomyelia: a syrinx was apparent in 74% of patients with a Grade II or Grade III odontoid angulation. Of holocord syringes, 70% were demonstrated in patients with a Grade III odontoid angulation. Curiously, no single grade of odontoid angulation
R. Shane Tubbs, Philip C. Johnson, Mohammadali M. Shoja, Marios Loukas and W. Jerry Oakes
position, the overlying muscles (trapezius, splenius capitis, semispinalis capitis) covering the posterior craniocervical junction were removed. Once the muscles that form the suboccipital triangle (that is, the rectus capitis posterior major) were identified, they were removed and the posterior arch of the atlas identified. If a foramen arcuale was present in the cadaveric specimen, the diameter of the VA was measured just before, within, and immediately after it traversed the foramen arcuale. All measurements including the length and thickness of the osseous strut were
R. Shane Tubbs, George Salter and W. Jerry Oakes
Object. The purpose of this anatomical study is to identify reliable external landmarks that can be used to determine accurately the lower border of the proximal segment of the transverse sinus (TS).
Methods. The authors used 15 formalin-fixed cadaveric specimens for this project. Various anatomical structures were dissected and measurements of the distance between these structures and the proximal TS were obtained.
The data collected in this study demonstrate that the inion is not always a reliable external landmark to use when determining the internal location of the very proximal TS and its drainage into the area of the torcular herophili. In addition, the authors found that the most accurate external landmark to use in reliably estimating the internal placement of the proximal TS is the point of insertion of the musculus semispinalis capitus and not the superior nuchal line. In the present study, this muscle never covered more than 5 mm of the inferior edge of the TS and was found to be a reliable anatomical structure for avoiding the medial segment of the TS.
Conclusions. These findings could aid the surgeon in localizing the TS with various midline approaches to the posterior fossa and the craniocervical junction.
study, this muscle never covered more than 5 mm of the inferior edge of the TS and was found to be a reliable anatomical structure for avoiding the medial segment of the TS. Conclusions. These findings could aid the surgeon in localizing the TS with various midline approaches to the posterior fossa and the craniocervical junction. We read with interest the paper by Tubbs and colleagues (Tubbs RS, Salter G, Oakes WJ: Superficial surgical landmarks for the transverse sinus and torcular herophili ( J Neurosurg 93: 279–281, August, 2000). The authors
R. Shane Tubbs, John C. Wellons III, Jeffrey P. Blount and W. Jerry Oakes
. 7 Fig. 1. Drawing showing the posterior view of the craniocervical junction. The PAO membrane is seen (arrow) . The PAO membrane has been historically referenced as the cephalad extension of the ligamentum flavum; hence, in earlier studies it was thought to play a role in craniocervical stability. 15, 17 The authors of more recent studies, however, have shown that the PAO membrane plays an insignificant role in atlantooccipital stability. 4, 8, 9, 14, 16 The tensile strength of this membrane, however, has been found to be fourfold that of the
Bermans J. Iskandar, Gary L. Hedlund, Paul A. Grabb and W. Jerry Oakes
out occult tumor as a cause of syringohydromyelia. The craniocaudal extent, morphological appearance, width, and anteroposterior dimension of the syrinx were recorded. Cine MR Imaging In addition to standard spin-echo techniques, we performed cerebrospinal fluid (CSF) flow dynamic studies with the 2-D phase-contrast cine MR technique, which uses the motion-sensitive nature of MR imaging to demonstrate flow dynamics at the craniocervical junction. Normal CSF movement is relatively synchronous with arterial pulsations. 9, 13 We performed qualitative analysis
R. Shane TUBBS, Charles Law, W. Jerry Oakes and Paul A. Grabb
age 7 days a VP shunt was placed. Three shunt malfunctions occurred, each preceded by severe emesis and irritability. A diagnosis of spastic quadriplegia was made when the patient was a toddler. A seizure disorder was also diagnosed, for which the patient receives Tegretol (100, 50, and 150 mg morning, noon, and night, respectively), and scoliosis was present with a thoracic convexity to the right. At 6 years of age the patient underwent MR imaging of the brain and craniocervical junction to ascertain the causes of his seizures ( Fig. 1 left ). At 8 years of age
R. Shane Tubbs, Daniel B. Webb and W. Jerry Oakes
our patients who underwent MR imaging this testing modality demonstrated flow anterior and posterior to the craniocervical junction following the first decompressive procedure. Sacco and Scott 17 recently reported on their experience with reoperation for Chiari malformations. In this mixed group of patients with CIM and Chiari II 100 were deemed to be CIM. Of this cohort 16 underwent repeated operation for continued symptoms. At second operation occluded fourth ventricle outflow, cervicomedullary compression from incomplete bone or dural opening, and improper