Purpose To determine the repeatability of magnetic resonance (MR) elastography-derived shear stiffness measurements of the intervertebral disc (IVD) taken throughout the day and their relationship with IVD degeneration and subject age. Materials and Methods In a cross-sectional study, in vivo lumbar MR elastography was performed once in the morning and once in the afternoon in 47 subjects without current low back pain (IVDs = 230; age range, 20-71 years) after obtaining written consent under approval of the institutional review board. The Pfirrmann degeneration grade and MR elastography-derived shear stiffness of the nucleus pulposus and annulus fibrosus regions of all lumbar IVDs were assessed by means of principal frequency analysis. One-way analysis of variance, paired t tests, concordance and Bland-Altman tests, and Pearson correlations were used to evaluate degeneration, diurnal changes, repeatability, and age effects, respectively. Results There were no significant differences between morning and afternoon shear stiffness across all levels and there was very good technical repeatability between the morning and afternoon imaging results for both nucleus pulposus (R = 0.92) and annulus fibrosus (R = 0.83) regions. There was a significant increase in both nucleus pulposus and annulus fibrosus MR elastography-derived shear stiffness with increasing Pfirrmann degeneration grade (nucleus pulposus grade 1, 12.5 kPa ± 1.3; grade 5, 16.5 kPa ± 2.1; annulus fibrosus grade 1, 90.4 kPa ± 9.3; grade 5, 120.1 kPa ± 15.4), and there were weak correlations between shear stiffness and age across all levels (R ≤ 0.32). Conclusion Our results demonstrate that MR elastography-derived shear stiffness measurements are highly repeatable, weakly correlate with age, and increase with advancing IVD degeneration. These results suggest that MR elastography-derived shear stiffness may provide an objective biomarker of the IVD degeneration process. RSNA, 2017 Online supplemental material is available for this article.

Both authors reported that they have no financial relationships that pose a potential conflict of interest with this article.

Study Design. Retrospective case series. Objective. To study the feasibility, outcomes, and complications of transpedicular vertebrectomy (TPV), and reconstruction for metastatic lesions to the thoracic spine. Summary of Background Data. Metastatic lesions to the thoracic spine may need surgical treatment requiring anterior–posterior decompression/stabilization. Anterior reconstruction may be performed using poly methyl meth acrylate (PMMA) cement or cages. Use of cement has been reported to be associated with complications. Methods. From 2008 to 2016, consecutive cases (single surgeon) undergoing TPV for thoracic spine metastasis (T2–12) were included. Demographic, surgical, and clinical data were collected through chart review. MRI, CT, positron emission tomography images were used to identify extent of disease, epidural spinal cord compression (ESCC), and degree of vertebral body collapse. Hall–Wellner confidence band was used for the survival curve. Results. Ninety six patients were studies with a median age 60 years. Most patients 56 (58%) presented with mechanical pain. 29% cases had lung metastasis. Single level TPV was performed in 73 patients (76%). Anterior reconstruction included PMMA in 78 patients (81.25%), and titanium cage in 18 patients (18.25%). Frankel grade improvement was seen in 16 cases (P = 0.013). ESCC improved by a median of 5.9 mm (P < 0.001). Kyphosis reduced by median of 7.5° (P < 0.001). VAS improved by median of seven (P < 0.001). Total 59 deaths were observed. The median survival time was estimated to be 6 months (95% CI: 5, 10). Surgical outcome and complication rates are similar between the two construct types. Correction of kyphosis was seen to be slightly better with the use of PMMA. Overall 29.16% cases developed complications (11.4% major). Two cases developed neurological deficit following epidural hematoma requiring surgery. One case had instrumentation failure from cement migration, needing revision. Conclusion. The result of our study shows significantly improved clinical and radiological outcomes for TPV for thoracic metastatic lesions. We also discuss some important steps for use of PMMA to avoid complications. Level of Evidence: 4

Background: Anterior cervical discectomy and fusion (ACDF) is a well-accepted treatment option for patients with cervical spine disease. Three- and four-level discectomies are known to be associated with a higher complication rate and lower fusion rate than single-level surgery. This study was performed to evaluate and compare zero-profile fixation and stand-alone PEEK cages for three- and four-level ACDF.Methods: Two cohorts of patients who underwent ACDF for the treatment of three- and four-level disease were compared. Thirty-three patients underwent implantation of zero-profile devices that included titanium screw fixation (Group A). Thirty-five patients underwent implantation of stand-alone PEEK cages without any form of screw fixation (Group B).Results: In Group A, twenty-seven patients underwent a three-level and six patients a four-level ACDF, with a total of 105 levels. In Group B, thirty patients underwent a three-level and five patients underwent a four-level ACDF, with a total number of 110 levels. In Group A, the mean preoperative visual analog scale score (VAS) for arm pain was 6.4 (range 3-8), and the mean postoperative VAS for arm pain decreased to 2.5 (range 1-7). In group B, the mean preoperative VAS of arm pain was 7.1 (range 3-10), and the mean postoperative VAS of arm pain decreased to 2 (range 0-4). In Group A, four patients (12%) developed dysphagia, and in Group B, three patients (9%) developed dysphagia. Conclusions: This study found zero-profile instrumentation and PEEK cages to be both safe and effective for patients who underwent three- and four-level ACDF, comparable to reported series using plate devices. Rates of dysphagia for the cohort were much lower than reports using plate devices. Zero-profile segmental fixation devices and PEEK cages may be considered as viable alternatives over plate fixation for patients requiring multi-level anterior cervical fusion surgery.

The authors report a case of immunoglobulin G4–related disease (IgG4-RD) presenting as a paraspinal, epidural mass. This disease encompasses a host of autoimmune conditions that were previously thought to be separate entities. It is characterized by fibrosis, mediated by the aberrant proliferation and tissue invasion of IgG4-positive plasma cells, which can occur in any organ. As with other autoimmune conditions, it tends to be responsive to steroids and other immunosuppressants. It can rarely present as a tumefactive lesion of the central nervous system, creating the potential for misdiagnosis (given its similar radiological appearance to malignancy) and mistreatment. In 2015, a panel of experts convened to set forth guidelines for the diagnosis and treatment of IgG4-RD. In the case presented here, the patient initially presented with pain and weakness in the left upper extremity. Initial neuroimages revealed a contrast-enhancing mass extending from C-4 to T-1, invading the epidural spinal canal, encasing the exiting nerve roots, infiltrating the paraspinal musculature, and surrounding the left vertebral artery. A PET scan confirmed the mass was hypermetabolic, but results of fine-needle aspiration and CT-guided biopsy were inconclusive. Open biopsy yielded fibrotic tissue that met the pathological criteria for IgG4-RD: lymphoplasmacytic infiltrate, fibrosis in a storiform pattern, and obliterative phlebitis. The patient was treated with 2 doses of 4 mg of dexamethasone (Decadron) and then 50 mg of prednisone per day. Within 2 weeks, the mass was radiologically shown to have drastically decreased in size. The prednisone dose was decreased to 40 mg per day, and 100 mg of azathioprine per day was added. The patient continued to improve and the mass continued to decrease over the next 6 months. Currently, she has been weaned from all steroids and will be maintained on a daily dose of 100 mg of azathioprine.

OBJECTIVE The development of symptomatic adjacent-segment disease (ASD) is a well-recognized consequence of lumbar fusion surgery. Extension of a fusion to a diseased segment may only lead to subsequent adjacent-segment degeneration. The authors report the use of a novel technique that uses dynamic stabilization instead of arthrodesis for the surgical treatment of symptomatic ASD following a prior lumbar instrumented fusion. METHODS A cohort of 28 consecutive patients was evaluated who developed symptomatic stenosis immediately adjacent to a previous lumbar instrumented fusion. All patients had symptoms of neurogenic claudication refractory to nonsurgical treatment and were surgically treated with decompression and dynamic stabilization instead of extending the fusion construct using a posterior lumbar dynamic stabilization system. Preoperative symptoms, visual analog scale (VAS) pain scores, and perioperative complications were recorded. Clinical outcome was gauged by comparing VAS scores prior to surgery and at the time of last follow-up. RESULTS The mean follow-up duration was 52 months (range 17–94 months). The mean interval from the time of primary fusion surgery to the dynamic stabilization surgery was 40 months (range 10–96 months). The mean patient age was 51 years (range 29–76 years). There were 19 (68%) men and 9 (32%) women. Twenty-three patients (82%) presented with low-back pain at time of surgery, whereas 24 patients (86%) presented with lower-extremity symptoms only. Twenty-four patients (86%) underwent operations that were performed using single-level dynamic stabilization, 3 patients (11%) were treated at 2 levels, and 1 patient underwent 3-level decompression and dynamic stabilization. The most commonly affected and treated level (46%) was L3–4. The mean preoperative VAS pain score was 8, whereas the mean postoperative score was 3. No patient required surgery for symptomatic degeneration rostral to the level of dynamic stabilization during the follow-up period. CONCLUSIONS The use of posterior lumbar dynamic stabilization may offer a valid and safe option for the management of patients who develop ASD rostral to a previously instrumented arthrodesis. The technique may serve as an alternative to multilevel arthrodesis in this patient population. By implanting a dynamic stabilization device instead of an extension of a rigid construct, this might translate into a reduction in the development of yet another level of ASD.

Background: Metastasis to craniocervical area may result in instability manifesting as disabling pain, cranial nerve dysfunction, paralysis, or even death. Stabilization is required to prevent complications. Nonoperative treatment modalities are ineffective in providing stability and adequate pain relief. We present our experience of diagnosis, presentation, and surgical management for metastatic tumors to the upper cervical spine (UCS). Methods: Single-center single-surgeon database of consecutively operated posterior occiput-cervical fusion for metastasis to UCS was reviewed from 2007 to 2016. Demographics, clinical, and surgical data were collected through chart review. Pain scores based on Visual Analog Scale (VAS) and other radiological data were noted. Kaplan–Meier curve was used for survival analysis. Clinical outcomes and complications were recorded. Results: A total of 29 patients (17 females/12 males) had the mean age of 56.7 ± 13.5 (24–82). Predominant metastasis included from the breast in 9 (31.03%) cases, followed by renal in 5, melanoma in 4, and 3 each from lung and colon. Axis was involved in 24 cases (C2 body in 21, pedicle in 8 cases). Atlas was involved in 9 cases (lateral mass in 8 cases and arch in 3 cases) and occiput was involved in three cases. Average Spinal Instability Neoplastic Score was 10 ± 2.3 (7–14). Mild cord compression was seen in 7 cases. Fusion extended from occiput to C4 fusion ( n = 23), C5 ( n = 5), and C6 ( n = 1). Average blood loss was 364.8 ± 252.1 ml and operative time was 235 ± 51.9 min. Average length of stay was 7 ± 2.8 days (3–15). VAS improved from 8.3 ± 1.5 to 1 ± 1.1 ( P < 0.001). C2 angulation corrected from 2.1° ±5.3° (0°–17°) to 0.5° ±1.2° ( P = 0.045). Three patients each developed cardiopulmonary complications and deep infection. The average survival was 14.5 ± 15.1 (0.15–50) months. Conclusion: C2 body is the most common site of metastasis. Occiput-cervical fusion for unstable upper cervical metastasis offers a good palliative treatment for pain relief and improved quality of life.

Background: Non-functioning pituitary adenomas have been treated by gross total resection with the microscopic transsphenoidal approach being the standard for decades. Recently, the endoscope has been utilized as alternative with its possible advantages and disadvantages. Methods: In this study, the authors retrospectively reviewed 58 cases who underwent transsphenoidal non-functioning pituitary adenomas resection, 25 via the microscopic approach (group 1) and 33 via the endoscopic approach (group 2). Different aspects of the procedures were compared, including duration of surgery, incidence of post-operative cerebrospinal fluid leak (being one of the common complications after such procedures), length of hospital stay postoperatively, and most importantly the tumor volume reduction being measured in a novel method by creating a computer-generated threedimensional reconstruction of the tumor. Results: The length of hospital stay for group 1 ranged from 2 to 9 days (mean 3.6 days, SD 2.141) while in group 2, it ranged from 2 to 7 days (mean 3.727 days, SD 1.008). Operative time mean was 92.7 min in group 1 and 142.79 min in group 2. Intraoperative CSF leak was encountered in 40% (n = 10) of the cases in group 1 and in five cases (15.2%) from group 2. Volume reduction percentage had a mean of 82.4% in group 1 and 89.1% in group 2. Although the mean of volume reduction percentage was higher in group 2, yet this difference was found to be statistically insignificant with a p value of 0.141.Conclusion: Endoscopic approach showed superiority by having lower incidence of post-operative cerebrospinal fluid leak, length of hospital stay, and tumor volume reduction while the microscopic approach was only favored in having shorter mean duration of surgery.