Please check out the accompanying podcast of this blog post:
1. Jensen OK, Nielsen CV, Sørensen JS, Stengaard-Pedersen K. Type 1 Modic changes was a significant risk factor for 1-year outcome in sick-listed low back pain patients: a nested cohort study using magnetic resonance imaging of the lumbar spine. Spine J. 2014;14(11):2568–2581. doi:10.1016/j.spinee.2014.02.018.
The authors evaluated 325 sick-listed LBP patients, of which 141 subjects were consecutively examined by MR, and 140 completed the study. They looked at the associations between baseline degenerative manifestations and outcome in these sick-listed LBP patients. Modic changes (MC) were identified in 60% of the patients, 18% with Type 1 changes and 42% with Type 2 changes. Following regression analysis, the authors assert that Type I MC were significantly associated with limited ability to return to work. Similar findings were not encountered for Type II MC.
This paper adds to the growing body of literature that correlates MC’s with LBP. The correlation seems to be stronger with endplate changes than with simple disc degeneration.
See also: Jensen, T. S., Karppinen, J., Sorensen, J. S., Niinimäki, J., & Leboeuf-Yde, C. Vertebral endplate signal changes (Modic change): a systematic literature review of prevalence and association with non-specific low back pain. European Spine Journal, 2008; 17(11): 1407–22. doi:10.1007/s00586-008-0770-2
2. Nelson EM, Monazzam SM, Kim KD, Seibert JA, Klineberg EO. Intraoperative fluoroscopy, portable X-ray, and CT: patient and operating room personnel radiation exposure in spinal surgery. Spine J. 2014;14(12):2985–91. doi:10.1016/j.spinee.2014.06.003.
2a. Prasarn ML. Commentary on: Intraoperative fluoroscopy, portable X-ray, and CT: patient and operating room personnel radiation exposure in spinal surgery. Spine J. 2014;14(12):2992–4. doi:10.1016/j.spinee.2014.07.006.
Nelson and coauthors evaluated the radiation exposure to patients and OR staff during spine surgery with C-arm fluoroscopy (C-arm), portable X-ray (XR) radiography, and portable cone-beam computed tomography (O-arm). Using a phantom, radiation exposure was measured with ion chamber dosimeters looking at exposures at common positions occupied by OR staff for C-arm, XR, and O-arm in typical image acquisition during spine surgery. Notable findings included that the lateral C-arm acquisition had a 7.7-fold increase in radiation exposure was measured on the X-ray tube side compared with the detector side. Anesthesiologist scatter radiation level for a single acquisition was highest for O-arm, followed by XR and C-arm. The radiologic technologist scatter radiation level was highest for XR, followed by O-arm and fluoroscopy.
For radiologists with our training in radiation physics and protection, this is not a surprising outcome. The inverse square law is a powerful thing. So, don’t stand beside the anode during fluoroscopy!
3. Nagata K, Yoshimura N, Hashizume H, et al. The prevalence of cervical myelopathy among subjects with narrow cervical spinal canal in a population-based magnetic resonance imaging study: the Wakayama Spine Study. Spine J. 2014;14(12):2811–7. doi:10.1016/j.spinee.2014.03.051.
3a. Emery SE. Commentary on: The prevalence of cervical myelopathy among subjects with narrow cervical spinal canal in a population-based magnetic resonance imaging study: the Wakayama Spine Study. Spine J. 2014;14(12):2818. doi:10.1016/j.spinee.2014.06.030.
Few studies have focused on age-related differences in the cervical spinal cord and the cervical spinal canal (CSC). In this study the authors evaluated age-related changes of the CSC in a population-based cohort in Japan and to examine the associated MR abnormalities including cervical cord compression and cord increased signal intensity (ISI). The Wakayama Spine Study was conducted between 2008 and 2010, and after exclusions and dropouts, both MRI and radiographic results were available for 959 participants (319 men and 640 women) with an age range of 21 to 97 years (mean, 67.3 years for men and 65.9 years for women). The participants completed an interviewer-administered questionnaire of 400 items that included lifestyle information; and anthropometric and physical performance measurements were taken. CSC diameter was narrower with age in both men and women in the population-based cohort. The prevalence of the clinical myelopathy was significantly higher in the narrower CSC group. In the logistic model, the CSC diameter was a significant predictive factor for clinical myelopathy.
As Dr. Emery notes in the accompanying editorial, the canal diameter measurements were (appropriately) performed at the midbody level and not at the disc spaces. This represents the developmental size of the spinal canal, and as the authors point out is minimally if at all influenced by degenerative changes. Of course, the most severe central stenosis will occur with degenerative change and disc osteophyte narrowing, which is not covered by this research.
4. Bydon M, Fredrickson V, De la Garza-Ramos R, et al. Sacral fractures. Neurosurg Focus. 2014;37(1):E12. doi:10.3171/2014.5.FOCUS1474
Very nice review article covering all aspects of this pathology. 8 Figures including 4 graphics, 3 CT and 1 plain film.
5. Miller J a, Lubelski D, Alvin MD, Benzel EC, Mroz TE. C5 palsy after posterior cervical decompression and fusion: cost and quality-of-life implications. Spine J. 2014;14(12):2854–60. doi:10.1016/j.spinee.2014.03.038.
This is a nice companion paper to 5a below, to emphasize the importance of the postoperative complication of C5 palsy. C5 palsy is a potentially debilitating complication of cervical decompression surgery that presents with paresis of the deltoid and/or biceps brachii muscles. This complication can be seen with both anterior and posterior decompressions of the cervical spine. Up to an 8.5% incidence have been reported with anterior approaches. While the overall prognosis is typically good, the weakness of the biceps and/or deltoid muscles may cause inability to perform basic and complex activities of daily living, with a resultant decreased quality of life. In this study of patients having posterior cervical decompressions, the authors documented that postoperative C5 palsy significantly impacted the capacity for self-care and the ability to perform usual activities. Also, the costs of care were elevated for the C5 palsy group, with a significant increase in the use of physical and occupational therapy.
5a. Bydon M, Macki M, Aygun N, et al. Development of postoperative C5 palsy is associated with wider posterior decompressions: an analysis of 41 patients. Spine J. 2014;14(12):2861–7. doi:10.1016/j.spinee.2014.03.040.
The authors retrospectively reviewed patient records and imaging of patients undergoing posterior laminectomy with foraminotomy and posterior fusion over a 7-year period. All cases included the C4–C5 level. Of 41 patients meeting these criteria, 9 were diagnosed with postoperative C5 palsy. They found that wider C5 foraminotomies were statistically correlated with greater posterior cord shifts, and both factors influenced the incidence C5 palsy after a logistic regression. They postulate that greater amounts of cord shift can increase the tension on the nerve roots, and may be associated with increased risk of C5 palsy.
6. Ellingson BM, Salamon N, Grinstead JW, Holly LT. Diffusion tensor imaging predicts functional impairment in mild-to-moderate cervical spondylotic myelopathy. Spine J. 2014;14(11):2589–97. doi:10.1016/j.spinee.2014.02.027.
The authors evaluated 48 cervical spondylosis patients with or without spinal cord signal change who underwent DTI of the spinal cord along with functional assessment via modified Japanese Orthopedic Association (mJOA) score. Fractional anisotropy (FA), mean diffusivity (MD), radial and axial diffusion (AD) coefficient, AD anisotropy, and the standard deviation (SD) of primary eigenvector orientation were evaluated. A relatively small number of 6 diffusion-sensitizing directions were used to estimate the diffusion tensor. DTI results were correlated with severity of cervical spondylotic myelopathy (CSM). DTI appeared to have relatively high sensitivity and specificity for detecting patients with symptomatic CSM.
7. Gruber HE, Hoelscher GL, Bethea SF, et al. Cortistatin is endogenous to the human intervertebral disc and exerts in vitro mitogenic effects on annulus cells and a downregulatory effect on TNF-α expression. Spine J. 2014;14(12):2995–3001. doi:10.1016/j.spinee.2014.06.002.
Cortistatin (CST) is a recently discovered cyclic neuropeptide with anti-inflammatory properties, similar to somatostatin, but encoded via a different gene. The authors evaluated 12 discs for immunohistochemistry, four annulus specimens used for cell culture with proinflammatory cytokines, and 11 for cell proliferation analyses. The authors found that CST is present in the human disc. This is notable because of the elevated proinflammatory cytokines which are important components in disc degeneration, such as TNF. This study also suggests that CST expression is downregulated by TNF-alpha.
8. Shi B, Zheng X, Min S, Zhou Z, Ding Z, Jin A. The morphology and clinical significance of the dorsal meningovertebra ligaments in the cervical epidural space. Spine J. 2014;14(11):2733–9. doi:10.1016/j.spinee.2014.04.014.
The authors performed a dissection-based study of 22 embalmed cadavers, with attention given to the presence of posterior dural ligamentous attachments. They found that in the cervical spine, the dorsal meningovertebral ligaments do exist between the posterior dural sac and the ligamentum flavum or lamina.
I am much more familiar with the anterior version of these ligaments in the lumbar spine, the so-called Hofman ligaments. These can be seen reasonably often, particularly when there is epidural lipomatosis. Since that rarely (if ever) occurs in the cervical spine, I suspect that visualizing these cervical ligaments with MR would be very difficult.
