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Objectives: Modic type 1 changes (MC1) are vertebral endplate bone marrow (BM) lesions observed on magnetic resonance images in sub-populations of chronic low back pain (CLBP) patients. The etiopathogenesis remains unknown and treatments that modify the underlying pathomechanisms do not exist. We hypothesized that two biological MC1 subtypes exist: a bacterial and a non-bacterial. This would have important implications for developing treatments targeting the underlying pathomechanisms., Methods: Intervertebral disc (IVD) samples adjacent to MC1 (n ​= ​34) and control (n ​= ​11) vertebrae were collected from patients undergoing spinal fusion. Cutibacterium acnes ( C.acnes ) genome copy numbers (GCNs) were quantified in IVD tissues with 16S qPCR, transcriptomic signatures and cytokine profiles were determined in MC1 and control BM by RNA sequencing and immunoassay. Finally, we assessed if C.acnes GCNs are associated with blood plasma cytokines., Results: IVD tissues from control levels had <870 ​ C.acnes GCNs/gram IVD. MC1-adjacent IVDs had either "low" (<870) or "high" (>870) C.acnes GCNs. MC1 patients with "high" C.acnes GCNs had upregulated innate immune cell signatures (neutrophil, macrophage/monocyte) and pro-inflammatory cytokines related to neutrophil and macrophage/monocyte function in the BM, consistent with a host defense against bacterium. MC1 patients with "low" C.acnes GCNs had increased adaptive immune cell signatures (T-and B-cell) in the BM and elevated IL-13 blood plasma levels., Conclusion: Our study provides the first evidence for the existence of bacterial ( C.acnes "high") and non-bacterial ( C.acnes "low") subtypes in MC1 patients with CLBP. This supports the need for different treatment strategies., Competing Interests: OD has/had consultancy relationship with and/or has received research funding from and/or has served as a speaker for the following companies in the area of potential treatments for systemic sclerosis and its complications in the last three calendar years: 4P-Pharma, AbbVie, Acceleron, Alcimed, Altavant, Amgen, AnaMar, Argenx, Arxx, AstraZeneca, Blade, Bayer, Boehringer Ingelheim, Corbus, CSL Behring, Galderma, Galapagos, Glenmark, Gossamer, Horizon, Janssen, Kymera, Lupin, Medscape, Merck, Miltenyi Biotec, Mitsubishi Tanabe, Novartis, Prometheus, Redxpharma, Roivant and Topadur. Patent issued “mir-29 for the treatment of systemic sclerosis” (US8247389, EP2331143). Co-founder of CITUS AG. SD is an inventor of the patent of Aclarion., (© 2024 The Author(s).)

Modic type 1 changes (MC1) are vertebral bone marrow lesions and associate with low back pain. Increased serum C-reactive protein (CRP) has inconsistently been associated with MC1. We aimed to provide evidence for the role of CRP in the tissue pathophysiology of MC1 bone marrow. From 13 MC1 patients undergoing spinal fusion at MC1 levels, vertebral bone marrow aspirates from MC1 and intrapatient control bone marrow were taken. Bone marrow CRP, interleukin (IL)-1, and IL-6 were measured with enzyme-linked immunosorbent assays; lactate dehydrogenase (LDH) was measured with a colorimetric assay. CRP, IL-1, and IL-6 were compared between MC1 and control bone marrow. Bone marrow CRP was correlated with blood CRP and with bone marrow IL-1, IL-6, and LDH. CRP expression by marrow cells was measured with a polymerase chain reaction. Increased CRP in MC1 bone marrow (mean difference: +0.22 mg CRP/g, 95% confidence interval [CI] [-0.04, 0.47], p = 0.088) correlated with blood CRP (r = 0.69, p = 0.018), with bone marrow IL-1β (ρ = 0.52, p = 0.029) and IL-6 (ρ = 0.51, p = 0.031). Marrow cells did not express CRP. Increased LDH in MC1 bone marrow (143.1%, 95% CI [110.7%, 175.4%], p = 0.014) indicated necrosis. A blood CRP threshold of 3.2 mg/L detected with 100% accuracy increased CRP in MC1 bone marrow. In conclusion, the association of CRP with inflammatory and necrotic changes in MC1 bone marrow provides evidence for a pathophysiological role of CRP in MC1 bone marrow., (© 2022 The Authors. Journal of Orthopaedic Research ® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Objectives: Augmented reality (AR), which entails overlay of in situ images onto the anatomy, may be a promising technique for assisting image-guided interventions. The purpose of this study was to investigate and compare the learning experience and performance of untrained operators in puncture of soft tissue lesions, when using AR ultrasound (AR US) compared with standard US (sUS)., Methods: Forty-four medical students (28 women, 16 men) who had completed a basic US course, but had no experience with AR US, were asked to perform US-guided biopsies with both sUS and AR US, with a randomized selection of the initial modality. The experimental setup aimed to simulate biopsies of superficial soft tissue lesions, such as for example breast masses in clinical practice, by use of a turkey breast containing olives. Time to puncture(s) and success (yes/no) of the biopsies was documented. All participants completed questionnaires about their coordinative skills and their experience during the training., Results: Despite having no experience with the AR technique, time to puncture did not differ significantly between AR US and sUS (median [range]: 17.0 s [6-60] and 14.5 s [5-41], p = 0.16), nor were there any gender-related differences (p = 0.22 and p = 0.50). AR US was considered by 79.5% of the operators to be the more enjoyable means of learning and performing US-guided biopsies. Further, a more favorable learning curve was achieved using AR US., Conclusions: Students considered AR US to be the preferable and more enjoyable modality for learning how to obtain soft tissue biopsies; however, they did not perform the biopsies faster than when using sUS., Key Points: • Performance of standard and augmented reality US-guided biopsies was comparable • A more favorable learning curve was achieved using augmented reality US. • Augmented reality US was the preferred technique and was considered more enjoyable., (© 2022. The Author(s).)

Purpose: Abdominal aortic aneurysms (AAAs) affect the vascular perfusion of the lumbar spine. The treatment of AAAs with endovascular aortic aneurysm repair (EVAR) completely occludes the direct vascular supply to the lumbar spine. We hypothesized that patients with AAA who undergo EVAR show a different pattern of spinal degeneration than individuals without AAA., Methods: In this retrospective institutional review board-approved study, 100 randomly selected patients with AAA who underwent EVAR with computed tomography (CT) scans between 2005 and 2017 were compared with age- and gender-matched controls without AAA. In addition, long-term follow-up CT images (> 6 months before EVAR, at the time of EVAR, and > 12 months after EVAR) of the patients were analysed to compare the progression of degeneration from before to after EVAR. Degeneration scores, lumbar levels with the most severe degeneration, and lumbar levels with progressive degeneration were analysed in all CT images. Fisher's exact test, Wilcoxon signed-rank test, and Mann-Whitney U test were performed for statistical analyses., Results: Compared with the control group (n = 94), the most severe degeneration was more commonly detected in the mid-lumbar area in the patient group (n = 100, p = 0.016), with significantly more endplate erosions being detected in the lumbar spine (p = 0.015). However, EVAR did not result in significant additional acceleration of the degenerative process in the long-term follow-up analysis (n = 51)., Conclusion: AAA is associated with atypical, more cranially located spinal degradation, particularly in the mid-lumbar segments; however, EVAR does not seem to additionally accelerate the degenerative process. This observation underlines the importance of disc and endplate vascularization in the pathomechanism of spinal degeneration., Level of Evidence I: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding., (© 2022. The Author(s).)

Background: Vertebral endplate signal intensity changes visualized by magnetic resonance imaging termed Modic changes (MC) are highly prevalent in low back pain patients. Interconvertibility between the three MC subtypes (MC1, MC2, MC3) suggests different pathological stages. Histologically, granulation tissue, fibrosis, and bone marrow edema are signs of inflammation in MC1 and MC2. However, different inflammatory infiltrates and amount of fatty marrow suggest distinct inflammatory processes in MC2., Aims: The aims of this study were to investigate (i) the degree of bony (BEP) and cartilage endplate (CEP) degeneration in MC2, (ii) to identify inflammatory MC2 pathomechanisms, and (iii) to show that these marrow changes correlate with severity of endplate degeneration., Methods: Pairs of axial biopsies ( n  = 58) spanning the entire vertebral body including both CEPs were collected from human cadaveric vertebrae with MC2. From one biopsy, the bone marrow directly adjacent to the CEP was analyzed with mass spectrometry. Differentially expressed proteins (DEPs) between MC2 and control were identified and bioinformatic enrichment analysis was performed. The other biopsy was processed for paraffin histology and BEP/CEP degenerations were scored. Endplate scores were correlated with DEPs., Results: Endplates from MC2 were significantly more degenerated. Proteomic analysis revealed an activated complement system, increased expression of extracellular matrix proteins, angiogenic, and neurogenic factors in MC2 marrow. Endplate scores correlated with upregulated complement and neurogenic proteins., Discussion: The inflammatory pathomechanisms in MC2 comprises activation of the complement system. Concurrent inflammation, fibrosis, angiogenesis, and neurogenesis indicate that MC2 is a chronic inflammation. Correlation of endplate damage with complement and neurogenic proteins suggest that complement system activation and neoinnervation may be linked to endplate damage. The endplate-near marrow is the pathomechanistic site, because MC2 occur at locations with more endplate degeneration., Conclusion: MC2 are fibroinflammatory changes with complement system involvement which occur adjacent to damaged endplates., Competing Interests: The authors declare no conflict of interest., (© 2022 The Authors. JOR Spine published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.)

Background Context: The biomechanical impact of spondylophytes on segmental stiffness is largely unknown, despite their high incidence., Purpose: The aim of this study was to quantify the biomechanical contribution according to location and cranio-caudal extent of spondylophytes and to create a clinically applicable radiological classification system., Study Design: Biomechanical cadaveric study., Methods: Twenty-six cadaveric human lumbar spinal segments with spondylophytes were tested with a displacement-controlled stepwise reduction method. The reduction in load required for the same motion after spondylophyte dissection was used to calculate the biomechanical contribution in flexion, extension, axial rotation, lateral bending, anterior, posterior and lateral shear. The spondylophytes were categorized by assessment of their anatomical position and cranio-caudal extent in computed tomography images (grade 1: spondylophytes spanning less than 50% of the disc-height, grade 2:>50%, grade 3:>90%, grade 4: bony bridging between the vertebrae) by two experienced radiologists. Cohen's kappa (κ) was used to report interreader reliability., Results: The largest biomechanical effect of non-bridging spondylophytes (grade 1-3) was recorded during contralateral bending with a grade-dependent contribution of up to 35%. Other loading directions including ipsilateral bending and translational loading were affected with values below 13%. Spondylophytes with osseous bridging (grade 4) show large contribution to the segmental stiffness in most loading conditions with values reaching over 80%. Interreader agreement for the spondylophyte grading was "substantial" (κ=0.73, p<.001)., Conclusions: The location and cranio-caudal extent of spondylophytes are essential parameters for their biomechanical effect. A reproducible classification has been validated biomechanically and helps evaluate the effect of specific spondylophyte configurations on segmental stiffness., Clinical Significance: Non-bridging spondylophytes primarily act as tensile structures and do not provide relevant propping. A classification system is presented to support understanding of the biomechanical consequences of different spondylophyte configuration for clinical decision making in surgical planning., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Back pain is one of the leading causes of health costs worldwide, particularly because of the further increased aging population. After clinical examination, spinal imaging is of utmost importance in many patients to reach the correct diagnosis. There are many imaging pitfalls and mimickers of spinal pathology on radiographs, magnetic resonance imaging, and computed tomography. These mimickers may lead to a misdiagnosis or a further imaging work-up if they are not recognized and thus lead to unnecessary examinations and increased health care costs. In this review we present the common mimickers of spinal pathology and describe normal variations when reading imaging studies of the spine., Competing Interests: Balgrist University Hospital has an academic research collaboration with Siemens Healthineers, Balzano Informatik and Bayer. Reto Sutter is a book editor and receives royalties from Breitenseher Publisher., (Thieme. All rights reserved.)

Purpose: To investigate the role of acromiohumeral distance (AHD) and critical shoulder angle (CSA) measurements from conventional radiographs (CR) in isolation and combined (prognostic index PI AHD-CSA ) as predictors of full thickness rotator cuff tendon tears (RCT) and critical fatty degeneration (CFD; i.e. as much fat as muscle)., Method: In this retrospective study AHD and CSA were measured in 127 CR. MR arthrograms served as reference standard and were screened for RCT and CFD. Statistical analysis for inter-reader agreement, Spearman's rank correlation, linear stepwise regression and logistic regression for AHD and CSA with ROC analyses including PI AHD-CSA were performed., Results: In 90 subjects (17 females, mean age 36.1 ± 14.1) no RCT were found on MR imaging and served as control group. In 37 patients (13 females, mean age 58.7 ± 13.2) ≥ one RCT was found. Inter-reader agreements rated between к = 0.42-0.82 for categorical and 0.91-0.96 for continuous variables. No significant correlation of AHD and CSA with either age or sex was seen (p = 0.28 and p = 0.74, respectively). Case group had significantly smaller mean AHD (8.7 ± 3.2 vs. 10.8 ± 2.2 mm; p < 0.001) and larger mean CSA (36.5 ± 4.5° vs. 33.1 ± 4.0°; p < 0.001). PI AHD-CSA increased diagnostic performance for prediction of RCT and CFD (AUC = 0.78 and 0.71), compared to isolated AHD (0.74 and 0.71) and CSA (0.71 and 0.66)., Conclusions: AHD and CSA do not depend on age or sex but differ significantly between healthy and pathologic rotator cuffs. A decreased AHD is most influenced by infraspinatus muscle atrophy and fatty degeneration. Combined PI AHD-CSA increases diagnostic performance for predicting RCT and CFD., (© 2022 The Authors.)

Background Context: Early postoperative MR images are frequently necessary after spine surgery. The appearance of commonly used adjunct hemostatic agents and dural sealants in MR images has not been systematically evaluated., Purpose: The purpose of this experimental study was to systematically analyze and describe the characteristics of the most commonly applied hemostatic agents and dural sealants in spine surgery on early postoperative MR images., Study Design: Cadaver Study METHODS: Four commonly applied dural sealants (Duraseal, Bioglue, Tachosil, Tisseel) and five commonly used hemostatic agents (Surgiflo, Bonewax, , Spongostan, Gelfoam, Avitene) were investigated. The experimental setting involved a human cadaver where a standard left-sided laminotomy was performed on nine levels of the thoracolumbar spine, and the materials were separately applied and mixed with fresh blood or water for hemostatic and dural sealants, respectively. The cadaver model was scanned at a 3 Tesla MRI and the imaging findings for all materials were compared to the surrounding tissue and systematically reported., Results: All investigated dural sealants and hemostatic agents were distinguishable from the surrounding tissue on MR images with different appearances on the MR sequences. A detailed atlas for the identification of the materials in postoperative spine MRI was established., Conclusion: Commonly used hemostatic agents and dural sealants can be successfully identified on early postoperative spine MRI., Clinical Significance: Knowledge about MRI appearances of commonly used adjunct surgical materials helps in interpretation of postoperative imaging and supports clinical decision making., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this study was to compare the results of a biphasic synthetic scaffold (TruFit, Smith & Nephew) to microfracture for the treatment of knee cartilage defects and identify patient- and lesion-specific factors that influence outcomes., Design: Prospectively collected data from 132 patients (mean age, 41.8 years; 69% male) with isolated chondral or osteochondral femoral defects treated with biphasic synthetic scaffolds ( n = 66) or microfracture ( n = 66) were reviewed. Clinical outcomes were evaluated longitudinally over 5 years with the Short Form-36 (SF-36), Activities of Daily Living of the Knee Outcome Survey (KOS-ADL), International Knee Documentation Committee (IKDC), and Marx Activity Scale. Cartilage-sensitive magnetic resonance imaging (MRI) was performed to evaluate osseous integration and cartilage fill in a subgroup of patients. Multivariate regression analysis was used to identify predictors of clinical outcomes within the scaffold group., Results: Both groups demonstrated clinically significant improvements in knee clinical scores over 5 years ( P < 0.01). There were no significant differences in KOS-ADL and IKDC scores between groups up to 5 years postoperatively. Marx activity level scores in the microfracture group declined over time, while significant improvements in activity level scores were observed in the scaffold group over 5 years ( P < 0.01). Good-quality tissue fill and cartilage isointensity were more often observed in the scaffold group compared with the microfracture group, particularly with longer time intervals. Increasing age, high body mass index, prior microfracture, and traumatic etiology were predictors for inferior outcomes in the scaffold group., Conclusions: Activity level and MRI appearance following treatment of cartilage lesions with the biphasic synthetic scaffold were superior to microfracture over time in this nonrandomized, retrospective comparison.

Hydrostatic integrity of the intervertebral disc (IVD) is lost during the process of degeneration. Invasive pressure profilometry (IPP) can quantify it, however, is not applicable for clinical use. We aimed to investigate correlations between IPP and MRI findings to assess non-invasive MRI based methods for prediction of hydrostatic integrity of the intervertebral disc. The pressure profiles of 39 lumbar spinal segments originating from 22 human cadavers were recorded during axial compression in the neutral, the flexed and the extended positions. Disc pressure profiles were measured and mathematically transformed to a novel metric that quantifies pressure profile heterogeneity across the disc. The relationship between pressure profile inhomogeneity ("pressure score") and clinically established magnetic resonance-based classifications systems and demographic parameters was then tested using Spearman correlation tests. Pressure profile inhomogeneities were correlated with IVD degeneration (according to Pfirrmann, rho = 0.43, p = 0.006), endplate defects (according to Rajasekaran, rho = 0.39, p = 0.013), segmental degeneration (according to Farshad, rho = 0.41, p = 0.009) and age (rho = 0.32, p = 0.049). Modic changes per se did not affect the pressure profiles significantly (p = 0.23) and pressure scores did not correlate with BMI (rho = -0.21, p = 0.2). Heterogeneity of segmental IVD pressure profiles is a unique measure of disc function. We demonstrate that established clinical methods for MRI characterization of the intervertebral disc, the endplate and overall segmental degeneration all correlate with the hydrostatic integrity of the IVD and can be used for its assessment., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: AR based navigation of spine surgeries may not only provide accurate surgical execution but also operator independency by compensating for potential skill deficits. "Direct" AR-navigation, namely superposing trajectories on anatomy directly, have not been investigated regarding their accuracy and operator's dependence.Purpose of this study was to prove operator independent reliability and accuracy of both AR assisted pedicle screw navigation and AR assisted rod bending in a cadaver setting., Methods: Two experienced spine surgeons and two biomedical engineers (laymen) performed independently from each other pedicle screw instrumentations from L1-L5 in a total of eight lumbar cadaver specimens (20 screws/operator) using a fluoroscopy-free AR based navigation method. Screw fitting rods from L1 to S2-Ala-Ileum were bent bilaterally using an AR based rod bending navigation method (4 rods/operator). Outcome measures were pedicle perforations, accuracy compared to preoperative plan, registration time, navigation time, total rod bending time and operator's satisfaction for these procedures., Results: 97.5% of all screws were safely placed (<2 mm perforation), overall mean deviation from planned trajectory was 6.8±3.9°, deviation from planned entry point was 4±2.7 mm, registration time per vertebra was 2:25 min (00:56 to 10:00 min), navigation time per screw was 1:07 min (00:15 to 12:43 min) rod bending time per rod was 4:22 min (02:07 to 10:39 min), operator's satisfaction with AR based screw and rod navigation was 5.38±0.67 (1 to 6, 6 being the best rate). Comparison of surgeons and laymen revealed significant difference in navigation time (1:01 min; 00:15 to 3:00 min vs. 01:37 min; 00:23 to 12:43 min; p  = 0.004, respectively) but not in pedicle perforation rate., Conclusions: Direct AR based screw and rod navigation using a surface digitization registration technique is reliable and independent of surgical experience. The accuracy of pedicle screw insertion in the lumbar spine is comparable with the current standard techniques., Competing Interests: The authors declare no conflict of interest., (© 2021 The Author(s). Published by Elsevier Ltd on behalf of North American Spine Society.)

Study Design: Biomechanical cadaveric study., Objective: The aim of this study was to evaluate the effect of degeneration on biomechanical properties of the passive structures of the lumbar spine., Summary of Background Data: Although the load apportionment among the passive structures in healthy spines follows well-defined contribution patterns, it remains unknown how this load distribution and sagittal preload changes by degenerative processes of the intervertebral disc (IVD)., Methods: Fifty lumbar spinal segments were tested in a displacement-controlled stepwise reduction study in flexion, extension, axial rotation, lateral bending, anterior, posterior and lateral shear. The intertransverse ligaments (ITLs), supraspinous and interspinous ligaments (ISL&SSL), facet joint capsules (FJC), facet joints (FJ), ligamentum flavum (LF), posterior longitudinal ligament (PLL), anterior longitudinal ligament (ALL), and spondylophytes were subsequently reduced. The results were set in relation to IVD-degeneration, quantified with Pfirrmann classification., Results: In flexion, a load redistribution from LF (-28% n.s.) and PLL (-13% n.s.) towards the IVD (+9%, n.s.) is observed comparing grade 2 to 5 IVD degeneration, whereas in all other loading directions, a reduction of IVD-contribution from -12% to -53% is recorded. In axial rotation, anterior and lateral shear, more load is shared by the FJ (+4% n.s., +23% ∗, +13% n.s.). The preload of the ALL, LF, PLL, and IVD is reduced ranging from -0.06 Nm to -0.37 Nm., Conclusion: IVD degeneration is related to notable load-redistributions between the passive spinal structures. With further degeneration, reduced contribution of the LF and PLL and higher loads on the IVD are observed in flexion. In the other tested loading directions, the relative load on the IVD is reduced, whereas higher FJ-exposure in axial rotation, anterior and lateral shear is observed. Furthermore, the preload of the spinal structures is reduced. These observations can further the understanding of the degenerative cascade in the spine.Level of Evidence: N/A., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: The ligamentum flavum (LF), the inter- and supraspinous ligament (ISL&SSL) and the intertransverse ligament (ITL) are relevant spinal structures for segmental stability. The biomechanical effect of degeneration and aging on their biomechanical properties remains largely unknown., Purpose: The aim of this study was to assess the material properties of the ITL, ISL&SSL and LF and to correlate parameters of biomechanical function with LF-thickness, intervertebral disc (IVD) degeneration and age., Study Design: Biomechanical cadaveric study., Methods: MRI- and CT-scans of 50 human lumbar segments (Th12-L5) were used to assess the ISL (acc. to Keorochana), the grade of IVD degeneration (acc. to Pfirrmann) and to quantify LF-thickness. The ITL, ISL&SSL and LF were resected in the neutral position of the spinal segment with a specifically developed method to conserve initial strain. Ramp to failure testing was performed (0.5 mm/s) to record initial tension, slack length, stiffness and ultimate strength. The relationship between the biomechanical characteristics and age and radiological parameters were analyzed. There are no study-specific conflicts of interest and no external funding was received for this study., Results: With aging, a significant reduction in initial tension (r=-0.5, p<.01) and ultimate strength (r=-0.41, p<.01) of the LF was observed, while the effect on LF-stiffness and the characteristics of the other ligaments was non-significant. IVD-degeneration was correlated with a significant reduction in stiffness (r=-0.47, p=.001; r=-0.36, p=.01) and ultimate strength (r=-0.3, p=.04; r=-0.36, p=.01) of the LF and ISL&SSL respectively and a significant reduction in initial tension (r=-0.4, p<.01) of the LF. For the ITL, no significant correlation was observed. Comparing Pfirrman 2 to 5, this reduction was 40% to 80% for stiffness 60% to 70% for ultimate strength and 88% for initial tension of the LF. ISL&SSL-stiffness between Kerorochana grade A and D differed significantly (p=.03), while all other comparisons were non-significant (p>.05). LF-thickness did not correlate with the biomechanical properties of the LF (p>.05)., Conclusions: Aging is primarily related to biomechanical changes to the LF. IVD-degeneration is related to a relevant reduction in stiffness and ultimate strength of the LF and ISL&SSL, with a similar trend for the ITL. The ISL-specific Keorochana grading system provides only minimal biomechanical information and LF-thickness does not provide biomechanical information., Clinical Significance: Patient age and the degenerative state of the IVD can be used to evaluate the biomechanical characteristics of the dorsal spinal ligaments, which can be helpful in selecting the optimal surgical procedure (e.g. in decompression surgery) for a specific situation., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: Patient-specific template-guided (TG) pedicle screw placement currently achieves the highest reported accuracy in cadaveric and early clinical studies, with reports of reduced use of radiation and less surgical time. However, a clinical randomized controlled trial (RCT) eliminating potential biases is lacking. This study compares TG and standard freehand (FH) pedicle screw insertion techniques in an RCT., Methods: Twenty-four patients (mean age 64 years, 9 men and 15 women) scheduled consecutively and independently from this study for 1-, 2-, or 3-level lumbar fusion were randomized to either the FH (n = 12) or TG (n = 12) group. Accuracy of pedicle screw placement, intraoperative parameters, and short-term complications were compared., Results: A total of 112 screws (58 FH and 54 TG screws) were implanted in the lumbar spine. Radiation exposure was significantly less in the TG group (78.0 ± 46.3 cGycm2) compared with the FH group (234.1 ± 138.1 cGycm2, p = 0.001). There were 4 pedicle screw perforations (6.9%) in the FH group and 2 (3.7%) in the TG group (p > 0.99), with no clinical consequences. Clinically relevant complications were 1 postoperative pedicle fracture in the FH group (p > 0.99), 1 infection in the FH group, and 2 infections in the TG group (p > 0.99). There were no significant differences in surgical exposure time, screw insertion time, overall surgical time, or blood loss between the FH and TG groups., Conclusions: In this RCT, patient-specific TG pedicle screw insertion in the lumbar region achieved a high accuracy, but not better than a standardized FH technique. Even if intraoperative radiation exposure is less with the TG technique, the need for a preoperative CT scan counterbalances this advantage. However, more difficult trajectories might reveal potential benefits of the TG technique and need further research.

The purpose was to study if (1) diurnal changes occur in the entire spine and if (2) intervertebral discs (IVDs) of weightlifters (WL) have decreased baseline T2-values in the morning as well as (3) increased diurnal changes throughout the day. This prospective cohort study investigated healthy volunteers between 2015 and 2017. WL were required to have participated in weightlifting ≥ 4×/week for ≥ 5 years, while non-weightlifters (NWL) were limited to < 2×/week for ≥ 5 years. Both groups underwent magnetic resonance imaging (MRI) of the entire spine in the morning and evening. WL were requested to perform weightlifting in-between imaging. IVD regions of interest (nucleus pulposus) were defined and T2-maps were measured. Analysis consisted of unpaired t-test, paired t-test, propensity-score matching (adjusting for age and sex), and Pearson correlation. Twenty-five individuals (15 [60.0%] males) with a mean age of 29.6 (standard deviation [SD 6.9]) years were analyzed. Both groups (WL: n = 12 versus [vs.] NWL: n = 13) did not differ demographic characteristics. Mean IVD T2-values of all participants significantly decreased throughout the day (95.7 [SD 15.7] vs. 86.4 [SD 13.9] milliseconds [ms]) in IVDs of the cervical (71.8 [SD 13.4] vs. 64.4 [SD 14.1] ms), thoracic (98.8 [SD 19.9] vs. 88.6 [SD 16.3] ms), and lumbar (117.0 [SD 23.7] vs. 107.5 [SD 21.6] ms) spine (P < 0.001 each). There were no differences between both groups in the morning (P = 0.635) and throughout the day (P = 0.681), even after adjusting for confounders. It can be concluded that diurnal changes of the IVDs occurred in the entire (including cervical and thoracic) spine. WL and NWL showed similar morning baseline T2-values and diurnal changes. Weightlifting may not negatively affect IVDs chronically or acutely.

Background: Ultrasound (US) images are currently displayed on monitors, and their understanding needs good orientation skills. Direct overlay of US images onto the according anatomy is possible with augmented reality (AR) technologies. Our purpose was to explore the performance of US-guided needle placement with and without AR in situ US viewing., Methods: Three untrained operators and two experienced radiologists performed 200 US-guided punctures: 100 with and 100 without AR in situ US. The punctures were performed in two different phantoms, a leg phantom with soft tissue lesions and a vessel phantom. Time to puncture and number of needle passes were recorded for each puncture. Data are reported as median [range] according to their non-normal distribution., Results: AR in situ US resulted in reduced time (median [range], 13 s [3-101] versus 14 s [3-220]) and number of needle passes (median [range], 1 [1-4] versus 1 [1-8]) compared to the conventional technique. The initial gap in performance of untrained versus experienced operators with the conventional US (time, 21.5 s [3-220] versus 10.5 s [3-94] and needle passes 1 [1-8] versus 1 [1, 2]) was reduced to 12.5 s [3-101] versus 13 s [3-100] and 1 [1-4] versus 1 [1-4] when using AR in situ US, respectively., Conclusion: AR in situ US could be a potential breakthrough in US applications by simplifying operator's spatial orientation and reducing experience-based differences in performance of US-guided interventions. Further studies are needed to confirm these preliminary phantom results.

Background: Dorsal spinal instrumentation with cervical pedicle screws (CPS) and rod constructs is performed for numerous pathologies of the cervical spine, although technically demanding. Screw misplacement is biomechanically disadvantageous and carries the risk of neurovascular sequelae. The aim of this study was to assess the accuracy of patient-specific, template-guided CPS placement from C2 to C7 compared with the freehand technique., Methods: Patient-specific targeting guides were used for placement of 3.5 mm CPS from C2 to C7 in 4 cadaveric specimens. Template-guided instrumentation was randomized for each cervical level and side and the contralateral side instrumented likewise but with the freehand technique. No fluoroscopy was used at all, and the spinal canal was not opened for the freehand technique. Accuracy was assessed by computed tomography, grading perforations using a 2-mm increment method, and time efficiency was compared between the 2 techniques., Results: In total, 48 screws were inserted with an equal distribution of 24 screws (50%) in each of the 2 groups. Outer pedicle width averaged 5.1 ± 1.0 mm (range 2.7-7.8); 66.7% (n = 16) of template-guided versus 20.8% (n = 5) of freehand CPS were fully contained within the pedicle (P = 0.001), whereas 91.7% (n = 22) versus 50% (n = 12) were within the <2 mm "safe" zone (P = 0.001). The mean time for instrumentation per level and side was 03:09 ± 01:37 minutes for the template-guided versus 02:32 ± 01:04 minutes for the freehand technique (P = 0.132)., Conclusions: In a cadaver model, template-guided CPS placement has a significantly greater accuracy than the freehand technique. This accuracy is comparable with navigated techniques reported in the literature., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background Context: Pedicle screw loosening is common after spinal fusion and can be associated with pseudoarthrosis and pain. With suspicion of screw loosening on standard radiographs, CT is currently considered the advanced imaging modality of choice. MRI with new metal artifact reduction techniques holds potential to be sensitive in detection of screw loosening. The sensitivity and specificity of either of the imaging modalities are yet clear., Purpose: To evaluate the sensitivity and specificity of three different image modalities (standard radiographs, CT, and MRI) for detection of pedicle screw loosening., Study Design/setting: Cross-sectional diagnostic study., Patient Sample: Forty-one patients (159 pedicle screws) undergoing revision surgeries after lumbar spinal fusion between August 2014 and April 2017 with preoperative radiographs, CT, and MRI with spinal metal artifact reduction (STIR WARP and TSE high bandwidth sequences)., Outcome Measures: Sensitivity and specificity in detection of screw loosening for each imaging modality., Methods: Screw torque force was measured intraoperatively and compared with preoperative screw loosening signs such as peri-screw edema in MRI and peri-screw osteolysis in CT and radiographs. A torque force of less than 60 Ncm was used to define a screw as loosened., Results: Sensitivity and specificity in detection of screw loosening was 43.9% and 92.1% for MRI, 64.8% and 96.7% for CT, and 54.2% and 83.5% for standard radiographs, respectively., Conclusions: Despite improvement of MRI with metal artifact reduction MRI technique, CT remains the modality of choice. Even so, CT fails to detect all loosened pedicle screws., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Quantitative MRI allows assessment of shoulder rotator cuff (RC) muscles by Dixon MR sequences with calculation of fractional fat content (FF%) maps and diffusion tensor imaging (DTI) including tractography., Purpose: To compare FF% and DTI derived parameters among visually intact RC muscles, to compare 2D with 3D DTI measurements and to establish normative values., Study Type: Prospective., Subjects: Forty patients aged >18 years undergoing shoulder MR arthrography were included., Field Strength/sequence: MR arthrography of the shoulder including 3D multiecho Dixon and 3D echo-planar DTI sequences (15 gradient encoding directions, b-value 600 s/mm 2 ) was performed at 3.0T., Assessment: Muscles affected by RC tears or fatty infiltration of Goutallier grade ≥1 were excluded. Two independent radiologists measured FF%, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) by region-of-interest (ROI) placements at the Y-position of the scapula and 3D tractography of each muscle with qualitative evaluation was performed., Statistical Tests: Intraclass correlation coefficients (ICCs) and Cohen's kappa were used for interreader agreement and Pearson correlation coefficient to correlate quantitative measures with each other and age, independent-samples t-test, one-way analysis of variance (ANOVA), and Kruskal-Wallis test were performed to investigate differences between genders and muscles., Results: Qualitative and quantitative measurements showed moderate (κ = 0.41-0.56) to almost perfect (ICC = 0.75-0.99) agreement. There were weak but significant positive correlations of FF% with age (r = 0.273, P < 0.05) and FA-2D (r = 0.319-0.383, P < 0.05). Significant differences were found among RC muscles for ADC, radial diffusivity (RD), and tract homogeneity (all P < 0.05) but not between genders (all P ≥ 0.05). High correlations of 2D with 3D measurements for ADC (r = 0.639, P < 0.001) and FA (r = 0.628, P < 0.001) were seen., Data Conclusion: Quantitative MRI with estimation of FF% and DTI parameters shows significant age-associated changes and differences among visually intact RC muscles. High reproducibility and correlations of 2D with 3D DTI measurements can be expected., Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:109-117., (© 2018 International Society for Magnetic Resonance in Medicine.)

We aimed to investigate whether different transmission settings of the dual-transmit technology may influence the amount of heat induction around an implant material dependent on its location within the magnetic field. Metallic hip implants were positioned in the magnet of a 3-T scanner at various lateral offset positions in relation to the magnetic axis in a body-phantom tank filled with polyacrylic acid gel. The temperature increase close to the implants was measured during turbo spin-echo scanning using dual-channel parallel radiofrequency (RF) transmission with circular in comparison to elliptic RF polarization. Circularly polarized transmission (CPT) induced higher temperature increases (maximum 6.2 °C) than elliptically polarized transmission (EPT) (maximum 1.5 °C). The heat induction was dependent on the distance to the isocenter with increased heating by increased distance to the isocenter. EPT showed lower heating around implants compared to the CPT as commonly used in single-transmission system; further, less heating was observed for both transmission settings closer to the magnet isocenter., Competing Interests: Not applicableNot applicableMatthias Nittka is an employer of Siemens Healthcare, Germany. The company had no influence on this experiment. The other authors had full control of the results. None of the other authors have any competing interests in the manuscript.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Objectives: The association of disc degeneration (DD) and vertebral endplate degeneration (EPD) is still not well understood. This study aimed to find segmental predictive risk factors for DD and EPD and to illuminate associations of the disc, endplate and bone marrow changes in the process of degeneration., Methods: After institutional review board approval, 450 lumbar levels, followed up with MRI for at least 4 years, were retrospectively graded for DD according to Pfirrmann (PFG), for EPD according to the endplate score (EPS) and according to the presence, extension and type of Modic changes (MC). Clustered logistic regression and multivariate analysis was applied in nested, matched case-control subgroups to evaluate potential local risk factors for progression., Results: An EPS score of  ≥4 was identified as an independent risk factor for progression of DD (OR = 2.32, 95%CI:1.07-5.01,p = 0.03) and MC (OR = 5.49,95%CI:2.30-13.10,p < 0.001). Progression of DD was significantly accompanied by progression or evolution of MC (OR = 12.25,95%CI:1.49-100.6,p = 0.02) and with progression of EPS (OR = 1.71, 95%CI:1.00-1.05, p = 0.01). Once advanced DD has occurred, it becomes a risk factor for progression in EPS (OR = 2.24,95%CI:1.23-4.12,p < 0.01)., Conclusions: The degenerative processes in the disc, endplate and bone marrow are highly associated. An EPS ≥ 4 is an independent risk factor for DD and MC progression in a population with low back pain., Key Points: • The degenerative processes in the disc, endplate and bone marrow are associated. • An endplate score ≥4 is a risk factor for DD and MC progression. • Modic changes are last to occur in the development of segmental intervertebral degeneration. • A new segmental grading system is suggested.

Objective: The aim of this study was to compare the degree of artifact reduction in magnetic resonance imaging achieved with slice encoding for metal artifact correction (SEMAC) in combination with view angle tilting (VAT) and multiacquisition variable resonance image combination (MAVRIC) for standard contrast weightings and different metallic materials., Methods: Four identically shaped rods made of the most commonly used prosthetic materials (stainless steel, SS; titanium, Ti; cobalt-chromium-molybdenum, CoCr; and oxidized zirconium, oxZi) were scanned at 3 T. In addition to conventional fast spin-echo sequences, metal artifact reduction sequences (SEMAC-VAT and MAVRIC) with varying degrees of artifact suppression were applied at different contrast weightings (T1w, T2w, PDw). Two independent readers measured in-plane and through-plane artifacts in a standardized manner. In addition, theoretical frequency-offset and frequency-offset-gradient maps were calculated. Interobserver agreement was assessed using intraclass correlation coefficient., Results: Interobserver agreement was almost perfect (intraclass correlation coefficient, 0.86-0.99). Stainless steel caused the greatest artifacts, followed by CoCr, Ti, and oxZi regardless of the imaging sequence. While for Ti and oxZi rods scanning with weak SEMAC-VAT showed some advantage, for SS and CoCr, higher modes of SEMAC-VAT or MAVRIC were necessary to achieve artifact reduction. MAVRIC achieved better artifact reduction than SEMAC-VAT at the cost of longer acquisition times. Simulations matched well with the apparent geometry of the frequency-offset maps., Conclusions: For Ti and oxZi implants, weak SEMAC-VAT may be preferred as it is faster and produces less artifact than conventional fast spin-echo. Medium or strong SEMAC-VAT or MAVRIC modes are necessary for significant artifact reduction for SS and CoCr implants.

Background Magnetic resonance imaging (MRI) is the diagnostic modality of choice in defining soft tissue compromise of the spinal canal. Purpose To evaluate the reliability of postoperative MRI in the determination of level and side of lumbar spinal decompression surgery, investigated by two reviewers, in different levels of training and specialization. Material and Methods Postoperative MR images of 86 patients who underwent spinal decompression (single level, n = 70; multilevel, n = 16; revision decompression, n = 9) were reviewed independently by an experienced musculoskeletal radiologist and a fourth-year orthopedic surgery resident. The level (single or multiple) and side of previous surgical decompression were determined and compared to the surgical notes. We examined factors that may have influenced the reliability, including demographics, type of surgical decompression, use of a drain, and time interval from surgery to MRI. Results Significantly fewer levels were correctly determined by the resident (77/86 cases, 89.5%) compared with the radiologist (84/86 cases, 97.7%) ( P = 0.014). The resident interpreted significantly more MR images incorrectly in cases where a drain was used (n = 8; P < 0.001). Re-decompression cases were interpreted incorrectly significantly more often by both the radiologist (n = 2, P = 0.032) and the resident (n = 4, P = 0.014). Conclusion Determination of the level and side operated on in previous lumbar spinal decompression surgery on MRI has a high reliability, especially when performed by a musculoskeletal radiologist. However, this reliability is decreased in cases involving surgical drainage and same-level revision surgery.

Purpose: Dorsal spinal instrumentation with pedicle screw constructs is considered the gold standard for numerous spinal pathologies. Screw misplacement is biomechanically disadvantageous and may create severe complications. The aim of this study was to assess the accuracy of patient-specific template-guided pedicle screw placement in the thoracic and lumbar spine compared to the free-hand technique with fluoroscopy., Methods: Patient-specific targeting guides were used for pedicle screw placement from Th2-L5 in three cadaveric specimens by three surgeons with different experience levels. Instrumentation for each side and level was randomized (template-guided vs. free-hand). Accuracy was assessed by computed tomography (CT), considering perforations of <2 mm as acceptable (safe zone). Time efficiency, radiation exposure and dependencies on surgical experience were compared between the two techniques., Results: 96 screws were inserted with an equal distribution of 48 screws (50 %) in each group. 58 % (n = 28) of template-guided (without fluoroscopy) vs. 44 % (n = 21) of free-hand screws (with fluoroscopy) were fully contained within the pedicle (p = 0.153). 97.9 % (n = 47) of template-guided vs. 81.3 % (n = 39) of free-hand screws were within the 2 mm safe zone (p = 0.008). The mean time for instrumentation per level was 01:14 ± 00:37 for the template-guided vs. 01:40 ± 00:59 min for the free-hand technique (p = 0.013), respectively. Increased radiation exposure was highly associated with lesser experience of the surgeon with the free-hand technique., Conclusions: In a cadaver model, template-guided pedicle screw placement is faster considering intraoperative instrumentation time, has a higher accuracy particularly in the thoracic spine and creates less intraoperative radiation exposure compared to the free-hand technique.

Objectives: To report outcomes of a cohort with displaced femoral neck fractures (FNFs) treated with a length/angle-stable construct augmented with an endosteal fibular allograft serving as a biologic dowel., Design: Prospective., Setting: Level I Trauma Center., Patients: The study group consists of 27 patients with isolated FNF surgically treated by a single surgeon., Intervention: Open reduction of the femoral neck, fixed with a length- and angle-stable construct of 2 fully threaded cannulated screws augmented with an endosteal fibular allograft serving as a biologic dowel., Main Outcome Measurements: Clinical and radiographic outcomes of the fixation construct and the viability of both the femoral head and the fibular allograft, host response to the allograft and osseous union were evaluated using a specialized sequence of contrast-enhanced magnetic resonance imaging (MRI) obtained at 3 and 12 months postoperatively., Results: This construct resulted in high union rates (89%; 24 of 27). Two patients suffered early catastrophic failure and 1 patient developed fracture nonunion, all of wish underwent uneventful conversion to total hip arthroplasty. Three additional patients (11%) had removal of symptomatic implants. The clinical and radiographic outcomes were excellent. Twelve-month MRIs revealed either partial or complete osseous incorporation of 86% the fibular allografts without signs of adverse reaction of the host to the allograft. Femoral head osteonecrosis segments were noted in 76% of patients on MRI; however, radiographically, there were no signs of osteonecrosis or segmental collapse., Conclusions: The fibular allograft reconstructs the comminuted femoral neck, and the osteointegration overtime increases the strength of the host bone-graft interface. This added strength seems to provide the stability needed to better preserve the intraoperative reduction, obtain good outcomes, and reduce the complications associated with FNF., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Evaluating postoperative femoral neck facture (FNF) with metal fixation hardware is commonly performed using radiographs. MRI has greater sensitivity and specificity to evaluate osteonecrosis (ON) but is often challenging due to the image distortion caused by metallic hardware., Questions/purposes: The aim of this study is to compare fast spin-echo (FSE) and multi-acquisition variable-resonance image combination (MAVRIC) sequences in assessing ON following metallic fixation of FNF and determining feasibility of semi-quantitative perfusion using MAVRIC., Methods: Radiography and MRI were performed at 3 and 12 months postoperatively, using FSE and pre- and post-gadolinium contrast MAVRIC sequences in 21 FNF patients. The presence and volume of ON were recorded. Signal intensity (SI) enhancement was measured on the MAVRIC sequences within the center and rim of ON; with the ilium and femoral diaphysis as controls. The detection rate of ON between MAVRIC and FSE images was evaluated as the difference of percent enhancement across the defined regions of interest., Results: ON was detected in 0% of radiographs, in 67% of FSE, and in 76% of MAVRIC images at 3 months follow-up, with similar results at 12 months. MAVRIC images had larger ON volume than FSE images at both time points. A significant percentage SI enhancement was only detected in the ON rim., Conclusion: Radiographs could not detect ON following metallic fixation of FNF. MAVRIC is more sensitive than FSE for determining the volume of ON. SI measurements using MAVRIC may provide an indirect assessment of perfusion.

Background: Limited information exists on the clinical use of a synthetic osteochondral scaffold plug for cartilage restoration in the knee., Purpose/hypothesis: The purpose of this study was to compare the early magnetic resonance imaging (MRI) appearance, including quantitative T2 values, between cartilage defects treated with a scaffold versus a scaffold with platelet-rich plasma (PRP) or bone marrow aspirate concentrate (BMAC). The hypothesis was that the addition of PRP or BMAC would result in an improved cartilage appearance., Study Design: Cohort study; Level of evidence, 3., Methods: Forty-six patients with full-thickness cartilage defects of the femur were surgically treated with a control scaffold (n = 11), scaffold with PRP (n = 23), or scaffold with BMAC (n = 12) and were followed prospectively. Patients underwent MRI with a qualitative assessment and quantitative T2 mapping at 12 months after surgery. An image assessment was performed retrospectively by a blinded musculoskeletal radiologist. The cartilage phase was measured by cartilage fill and quantitative T2 values on MRI. A comparison between groups after cartilage repair was performed., Results: The control scaffold group consisted of 8 male and 3 female patients (mean age, 38 years; mean body mass index [BMI], 25 kg/m(2)), the PRP group had 15 male and 8 female patients (mean age, 39 years; mean BMI, 26 kg/m(2)), and the BMAC group consisted of 8 male and 4 female patients (mean age, 36 years; mean BMI, 26 kg/m(2)). The PRP-treated (P = .002) and BMAC-treated (P = .03) scaffolds had superior cartilage fill compared with the control group. With quantitative methods, the PRP group demonstrated a mean T2 value (49.1 ms) that was similar to that of the control scaffold group (42.7 ms; P = .07), but the BMAC group demonstrated a mean T2 value (60.5 ms) closer to that of superficial hyaline cartilage (P = .01). The stratification of T2 values between the deep and superficial zones was not observed in any of the groups., Conclusion: In this comparative study, patients treated with scaffold implantation augmented with BMAC had improved cartilage maturation with greater fill and mean T2 values closer to that of superficial native hyaline cartilage at 12 months. Further work will determine if this translates into improved clinical outcomes., (© 2015 The Author(s).)

Magnet resonance imaging (MRI) is the most commonly used imaging modality for diagnosis of degenerative disc disease (DDD). Lack of precise observations and documentation of aspects within the complex entity of DDD might partially be the cause of poor correlation of radiographic findings to clinical symptoms. This literature review summarizes the current knowledge on MRI in DDD and outlines the diagnostic limitations. The review further sensitizes the reader toward awareness of potentially untended aspects of DDD and the interaction of DDD and endplate changes. A summary of the available classifications for DDD is provided., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background Context: The relation between specific types of lumbosacral transitional vertebra and the degree of degeneration at and adjacent to the transitional level is unclear. It is also unknown whether the adjacent cephalad segment to a transitional vertebra is prone to greater degeneration than a normal L5-S1 level., Purpose: The purpose of this study was to evaluate the relation between specific lumbosacral transitional vertebra subtypes according to the Castellvi classification, and to determine the severity of degeneration at the transitional level and the adjacent cephalad segment., Study Design: This study was a retrospective review., Patient Samples: Ninety-two subjects with lumbosacral transitional vertebra grade 2 or higher and 94 control subjects without were retrieved from a picture archiving and communication system (PACS) search., Outcome Measures: Disc degeneration parameters at the transitional and at the adjacent cephalad level were measured., Methods: After institutional review board approval, 92 subjects (42 men; mean age, 57±16 years) with lumbosacral transitional vertebra grade 2 or higher and 94 control subjects (41 men; mean age, 51±16 years) without were retrieved from a PACS search. Degeneration of the last two segments of the lumbar spine was quantified using the Pfirrmann and Modic classifications, along with documentation of annular tears, disc herniations, and disc height, and were compared between the two groups. Furthermore, L5-S1 levels in the control subjects were compared with the adjacent cephalad segments of the transitional vertebrae for the same parameters., Results: Although the control subjects, at L5-S1, had moderate to severe degeneration by Pfirrmann grades (31%) and Modic changes ([MC] 20%), in comparison, the discs at the transitional level of the lumbosacral transitional vertebra group demonstrated significant less degeneration (3% and 1%, respectively; each p<.05). The adjacent cephalad segments of the lumbosacral transitional vertebra group showed significantly greater degeneration (Pfirrmann grade 5, 39%; MC, 30%) compared with the L4-L5 level in control subjects (16% and 11%, respectively; each p<.05). The severity of disc degeneration using all parameters correlated with the type of lumbosacral transitional vertebra. The degree of degeneration of L5-S1 in control subjects was similar to the adjacent cephalad segment in lumbosacral transitional vertebrae., Conclusion: Increasing the mechanical connection of a lumbosacral transitional vertebra protects the disc at the transitional level and predisposes the adjacent cephalad segment to greater degeneration. The adjacent cephalad segment had a comparable degree of degeneration as the L5-S1 level in control subjects., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: Anatomical landmarks and their relation to the lumbar vertebrae are well described in subjects with normal spine anatomy, but not for subjects with lumbosacral transitional vertebra (LSTV), in whom correct numbering of the vertebrae is challenging and can lead to wrong-level treatment. The aim of this study was to quantify the value of different anatomical landmarks for correct identification of the lumbar vertebra level in subjects with LSTV., Methods: After IRB approval, 71 subjects (57 ± 17 years) with and 62 without LSTV (57 ± 17 years), all with imaging studies that allowed correct numbering of the lumbar vertebrae by counting down from C2 (n = 118) or T1 (n = 15) were included. Commonly used anatomical landmarks (ribs, aortic bifurcation (AB), right renal artery (RRA) and iliac crest height) were documented to determine the ability to correctly number the lumbar vertebrae. Further, a tangent to the top of the iliac crests was drawn on coronal MRI images by two blinded, independent readers and named the 'iliac crest tangent sign'. The sensitivity, specificity and the interreader agreement were calculated., Results: While the level of the AB and the RRA were found to be unreliable in correct numbering of the lumbar vertebrae in LSTV subjects, the iliac crest tangent sign had a sensitivity and specificity of 81 % and 64-88 %, respectively, with an interreader agreement of k = 0.75., Conclusion: While anatomical landmarks are not always reliable, the 'iliac crest tangent sign' can be used without advanced knowledge in MRI to most accurately number the vertebrae in subjects with LSTV, if only a lumbar spine MRI is available.

Objective: Assessment of scoliotic curve flexibility and stiffness is essential for planning surgical treatment in adolescent idiopathic scoliosis (AIS). Measurement of curve flexibility is currently insufficiently precise. The purpose of this study was to introduce and validate a novel method of superimposing radiographs for more reliable measurement of curve flexibility., Material and Methods: Two independent radiologists measured Cobb angles separately on standard anterior-posterior (AP) (n = 48) and supine bending radiographs (n = 48), in patients with AIS, who were randomly included from a surgical database. The same readers repeated the measurements after the bending radiographs were semi-automatically superimposed on the AP radiographs by fusing the caudad end vertebra. Curve flexibility was calculated. Inter-reader agreement between the two independent readers was calculated using interclass correlation coefficient (ICC)., Results: A moderate inter-reader agreement was achieved in the upper curve (ICC = 0.57) and a good agreement in the lower curve (ICC = 0.72) with the standard method of assessing curve flexibility. With the use of the semiautomatic superimposition, however, almost perfect agreement was achieved for both the upper and the lower curves flexibilities (ICC = 0.93 and 0.97, respectively)., Conclusion: The introduced semi-automatic superimposition technique for measurement of scoliotic curve flexibility in AIS is more precise and reliable than the current standard method.

Purpose: Tendon tear may result in muscular retraction with the loss of contractile amplitude and strength of the rotator cuff muscles. Currently, neither a validated method of measuring supraspinatus tendon length nor normal values are known. It was therefore the purpose of this study to measure the normal length of the supraspinatus tendon and to determine whether partial tears are associated with changes in tendon length., Methods: MR examinations of 49 asymptomatic volunteers and 37 patients with arthroscopically proven, isolated partial tears of the supraspinatus tendon were compared. The ratio of the extramuscular tendon length to the distance between the footprint and the glenoid surface was calculated (TL/FG ratio). Tendon length measurements were taken by two independent readers at the bursal and articular surfaces at the anterior, the central and the posterior parts of the tendon., Results: TL/FG ratios at the bursal surface of tendons with partial tears were significantly higher than those in the control group [anterior: 0.78 ± 0.20 vs. 0.66 ± 0.15 (p < 0.05); central: 0.61 ± 0.13 vs. 0.52 ± 0.10 (p < 0.05); posterior: 0.57 ± 0.15 vs. 0.52 ± 0.10 (p < 0.05)]. At the articular surface, differences were significant only anteriorly [0.60 ± 0.13, vs. 0.54 ± 0.10 (p < 0.05)]. A cut-off TL/FG ratio of 0.63 for measurements at the bursal surface in the center of the tendon achieved a sensitivity of 46 % and a specificity of 92 % for the identification of partial cuff tearing., Conclusion: A reproducible method for measurement of extramuscular supraspinatus tendon length is described. Partial tearing of the supraspinatus tendon is associated with significant tendon lengthening, suggesting failure in continuity, and this is most reliably measured on the bursal surface., Level of Evidence: III.

Background: While convergent placement of pedicle screws in the axial plane is known to be more advantageous biomechanically, surgeons intuitively aim toward a parallel placement of screws in the sagittal plane. It is however not clear whether parallel placement of screws in the sagittal plane is biomechanically superior to a non-parallel construct. The hypothesis of this study is that sagittal non-parallel pedicle screws do not have an inferior initial pull-out strength compared to parallel placed screws., Methods: The established lumbar calf spine model was used for determination of pull-out strength in parallel and non-parallel intersegmental pedicle screw constructs. Each of six lumbar calf spines (L1-L6) was divided into three levels: L1/L2, L3/L4 and L5/L6. Each segment was randomly instrumented with pedicle screws (6/45 mm) with either the standard technique of sagittal parallel or non-parallel screw placement, respectively, under fluoroscopic control. CT was used to verify the intrapedicular positioning of all screws. The maximum pull-out forces and type of failure were registered and compared between the groups., Results: The pull-out forces were 5,394 N (range 4,221 N to 8,342 N) for the sagittal non-parallel screws and 5,263 N (range 3,589 N to 7,554 N) for the sagittal-parallel screws (p = 0.838). Interlevel comparisons also showed no statistically significant differences between the groups with no relevant difference in failure mode., Conclusion: Non-parallel pedicle screws in the sagittal plane have at least equal initial fixation strength compared to parallel pedicle screws in the setting of the here performed cadaveric calf spine experiments.

Objective: Sufficiently sized studies to determine the value of the iliolumbar ligament (ILL) as an identifier of the L5 vertebra in cases of a lumbosacral transitional vertebra (LSTV) are lacking., Methods: Seventy-one of 770 patients with LSTV (case group) and 62 of 611 subjects without LSTV with confirmed L5 level were included. Two independent radiologists using coronal MR images documented the level(s) of origin of the ILL. The interobserver agreement was analysed using weighted kappa/kappa (wκ/κ) and a Fischer's exact test to assess the value of the ILL as an identifier of the L5 vertebra., Results: The ILL identified the L5 vertebra by originating solely from L5 in 95 % of the controls; additional origins were observed in 5 %. In the case group, the ILL was able to identify the L5 vertebra by originating solely from L5 in 25-38 %. Partial origin from L5, including origins from other vertebra was observed in 39-59 % and no origin from L5 at all in 15-23 % (wκ = 0.69). Both readers agreed that an ILL was always present and its origin always involved the last lumbar vertebra., Conclusion: The level of the origin of the ILL is unreliable for identification of the L5 vertebra in the setting of an LSTV or segmentation anomalies., Key Points: • The origin of the ILL is evaluated in subjects with an LSTV. • The origin of the ILL is anatomically highly variable in LSTV. • The ILL is not a reliable landmark of the L5 vertebra in LSTV.

Background: Lateral patellar arthritis has been associated with poor outcomes in unicompartmental knee arthroplasty. The current study correlates intraoperative findings with MRI imaging, skyline radiographs and the presence of anterior knee pain., Methods: In 92 consecutive knees with varus arthritis, the patellofemoral compartment was assessed during surgery, on skyline radiographs and on MRI. Anterior knee pain was recorded on a visual-analog-scale. Intraoperative assessment was based on the Outerbridge grading scale. Skyline radiographs were evaluated according to the Ahlbäck grading scale; MRIs were assessed according to a modified Outerbridge grading scale., Results: There was an excellent correlation (rs=0.833; p<0.001) in the cartilage assessment of the lateral patellar facet between MRI and surgery. A good correlation (rs=0.664; p<0.001) was seen between Ahlbäck Grades and macroscopic Outerbridge Grades of the lateral patella. Ahlbäck Grades and MRI modified Outerbridge Grades showed a good correlation (rs=0.643; p<0.001) for the lateral patella. Twelve percent of knees (seven out of 60) with Ahlbäck Grade 0 or 1 and mild to moderate anterior knee pain had a macroscopic Outerbridge Grade of 3 on the lateral patella. None of these 60 knees had a full-thickness cartilage defect on MRI., Conclusion: Normal skyline radiographs in patients with mild to moderate anterior knee pain can rule out full-thickness cartilage defects of the lateral patellar facet as observed during surgery and on MRI. The MRI allows for the most accurate assessment of the patellofemoral joint and is warranted in all patients with radiographic abnormalities or severe anterior knee pain., Level of Evidence: Diagnostic study, Level II., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Purpose: It is questionable whether an annular tear (AT) is a predictor for accelerated degeneration of the intervertebral discs. The aim of the present study was to answer this question via a matched case-control study design that reliably eliminates potential confounders., Materials: Presence or absence of AT, defined as a hyperintense lesion within the annular fibrosus on T2-weighted non-contrast MRI images, was documented in 450 intervertebral lumbar discs of 90 patients who could be followed up for at least 4 years with MRI. Discs with an AT (n = 36) were matched 1:1 to control discs according to the level, degree of initial disc degeneration on MRI (both Pfirrmann grade median 4, range 3-4), age (59.5 ± 15.0 versus 59.3 ± 14.6 years), BMI (26.7 ± 4.4 versus 26.9 ± 4.4 kg/m(2)) and interval to the follow-up MRI (4.8 ± 0.9 versus 5.1 ± 0.8 years). The degree of disc degeneration after a minimum of 4 years was graded on the follow-up MRI in both groups according to the Pfirrmann classification., Results: One-fourth (25%) of the 36 discs with an AT on the initial MRI exam progressed in degeneration. This was similar to the rate of the matched control discs with no AT, in which also around one-fourth (22%) showed a progression of degeneration (p = 1.00), also without any difference in the degree of degeneration., Conclusion: Discs with a Pfirrmann grade >2 with an AT, defined by a hyperintense signal intensity on MRI, are not prone to accelerated degeneration if compared to discs without an AT. Therefore, the presence of an AT per se does not predict accelerated disc degeneration.

Purpose: Evolution and progression of disc and endplate bone marrow degeneration of the lumbar spine are thought to be multifactorial, yet, their influence and interactions are not understood. The aim of this study was to find association of potential predictors of evolution of degeneration of the lumbar spine., Methods: Patients (n = 90) who underwent two lumbar magnetic resonance imaging (MRI) exams with an interval of at least 4 years and without any spinal surgery were included into the longitudinal cohort study with nested case-control analysis. Disc degeneration (DD) was scored according to the Pfirrmann classification and endplate bone marrow changes (EC) according to Modic in 450 levels on both MRIs. Potential variables for degeneration such as age, gender, BMI, scoliosis and sagittal parameters were compared between patients with and without evolution or progression of degenerative changes in their lumbar spine. A multivariate analysis aimed to identify the most important variables for progression of disc and endplate degeneration, respectively., Results: While neither age, gender, BMI, sacral slope or the presence of scoliosis could be identified as progression factor for DD, a higher lordosis was observed in subjects with no progression (49° ± 11° vs 43° ± 12°; p = 0.017). Progression or evolution of EC was only associated with a slightly higher degree of scoliosis (10° ± 10° vs 6° ± 9°; p = 0.04) and not to any of the other variables., Conclusion: While a coronal deformity of the lumbar spine seems associated with evolution or progression of EC, a higher lumbar lordosis is protective for radiographic progression of DD. This implies that scoliotic deformity and lesser lumbar lordosis are associated with higher overall degeneration of the lumbar spine.

Background Context: Different types of lumbosacral transitional vertebra (LSTV) are classified based on the relationship of the transverse process of the last lumbar vertebra to the sacrum. The Ferguson view (30° angled anteroposterior [AP] radiograph) is supposed to have a sufficient interreader reliability in classification of LSTV, but is not routinely available. Standard AP radiographs and magnetic resonance imaging (MRI) are often available, but their reliability in detection and classification of LSTV is unknown., Purpose: The purpose of this study was to evaluate the interreader reliability of detection and classification of LSTV with standard AP radiographs and report its accuracy by use of intermodality statistics compared with MRI as the gold standard., Study Design/setting: Retrospective case control study., Patient Sample: A total of 155 subjects (93 cases: LSTV type 2 or higher; 62 controls)., Outcome Measures: Interreader reliability in detection and classification of LSTV using standard AP radiographs and coronal MRI as well as accuracy of radiographs compared with MRI., Methods: After institutional review board approval, coronal MRI scans and conventional AP radiographs of 155 subjects (93 LSTV type 2 or higher and 62 controls) were retrospectively reviewed by two independent, blinded readers and classified according to the Castellvi classification. Interreader reliability was assessed using kappa statistics for detection of an LSTV and identification of all subtypes (six variants; 1: no LSTV or type I, 2: LSTV type 2a, 3: LSTV type 2b, 4: LSTV type 3a, 5: LSTV type 3b, 6: LSTV type 4) for MRI scans and standard AP radiographs. Further, accuracy and positive and negative predictive values were calculated for standard AP radiographs to detect and classify LSTV using MRI as the gold standard., Results: The interreader reliability was at most moderate for the detection (k=0.53) and fair for classification (wk=0.39) of LSTV in standard AP radiograph. However, the interreader reliability was very good for detection (k=0.93) and classification (wk=0.83) of LSTV in MRI. The accuracy and positive and negative predictive values of standard AP radiograph were 76% to 84%, 72% to 86%, and 79% to 81% for the detection and 53% to 58%, 51% to 76%, and 49% to 55% for the classification of LSTV, respectively., Conclusion: Standard AP radiographs are insufficient to detect or classify LSTV. Coronal MRI scans, however, are highly reliable for classification of LSTV., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: The multifidus muscle is the only paraspinal lumbar muscle that is innervated by a single nerve root. This study aimes to evaluate if the asymmetry of the multifidus muscle is related to the severity of compression of the nerve root or the duration of radiculopathy., Methods: MRI scans of 79 patients with symptomatic single level, unilateral, lumbar radiculopathy were reviewed for this retrospective case series with a nested case-control study. The cross-sectional area (CSA) of the multifidus muscle and the perpendicular distance of the multifidus to the lamina (MLD) were measured bilaterally by two radiologists and set into relation to the severity of nerve compression, duration of radiculopathy and probability of an indication for surgical decompression., Results: In 67 recessal and 12 foraminal symptomatic nerve root compressions, neither the MLD ratio (severe 1.19 ± 0.55 vs less severe nerve compression: 1.12 ± 0.30, p = 0.664) nor the CSA ratio (severe 1 ± 0.16 vs less severe 0.98 ± 0.13, p = 0.577) nor the duration of symptoms significantly correlated with the degree of nerve compression. MR measurements of multifidus were not different in patients with (n = 20) and those without (n = 59) clinical muscle weakness in the extremity caused by nerve root compression. A MLD >1.5 was, however, associated with the probability of an indication for surgical decompression (OR 3, specificity 92%, PPV 73%)., Conclusions: Asymmetry of the multifidus muscle correlates with neither the severity nor the duration of nerve root compression in the lumbar spine. Severe asymmetry with substantial multifidus atrophy seems associated with the probability of an indication of surgical decompression.

Background: Borreliosis is a widely distributed disease. Neuroborreliosis may present with unspecific symptoms and signs and often remains difficult to diagnose in patients with central nervous system symptoms, particularly if the pathognomonic erythema chronica migrans does not develop or is missed. Thus, vigilance is mandatory in cases with atypical presentation of the disease and with potentially severe consequences if not recognized early. We present a patient with neuroborreliosis demonstrating brain stem and vestibular nerve abnormalities on magnetic resonance imaging., Case Presentation: A 28-year-old Caucasian female presented with headaches, neck stiffness, weight loss, nausea, tremor, and gait disturbance. Magnetic resonance imaging showed T2-weighted hyperintense signal alterations in the pons and in the vestibular nerves as well as bilateral post-contrast enhancement of the vestibular nerves. Serologic testing of the cerebrospinal fluid revealed the diagnosis of neuroborreliosis., Conclusion: Patients infected with neuroborreliosis may present with unspecific neurologic symptoms and magnetic resonance imaging as a noninvasive imaging tool showing signal abnormalities in the brain stem and nerve root enhancement may help in establishing the diagnosis.

The purpose of this study was to devise a simple but reliable radiological method of identifying a lumbosacral transitional vertebra (LSTV) with a solid bony bridge on sagittal MRI, which could then be applied to a lateral radiograph. The vertical mid-vertebral angle (VMVA) and the vertical anterior vertebral angle (VAVA) of the three most caudal segments of the lumbar spine were measured on MRI and/or on a lateral radiograph in 92 patients with a LSTV and 94 controls, and the differences per segment (Diff-VMVA and Diff-VAVA) were calculated. The Diff-VMVA of the two most caudal vertebrae was significantly higher in the control group (25° (sd 8) than in patients with a LSTV (type 2a+b: 16° (SD 9), type 3a+b: -9° (SD 10), type 4: -5° (SD 7); p < 0.001). A Diff-VMVA of ≤ +10° identified a LSTV with a solid bony bridge (type 3+4) with a sensitivity of 100% and a specificity of 89% on MRI and a sensitivity of 94% and a specificity of 74% on a lateral radiograph. A sensitivity of 100% could be achieved with a cut-off value of 28° for the Diff-VAVA, but with a lower specificity (76%) on MRI than with Diff-VMVA. Using this simple method (Diff-VMVA ≤ +10°), solid bony bridging of the posterior elements of a LSTV, and therefore the first adjacent mobile segment, can be easily identified without the need for additional imaging.

Knee ligament instability may lead to meniscal and chondral damage, resulting in early osteoarthritis. Due to its superior soft tissue contrast and avoidance of harmful ionizing radiation, MRI has become the most important imaging modality for early recognition of structural defects of the knee joint. This review aims to the understanding of MRI appearances of knee ligament structures associated with knee instability, and to review the common patterns of altered knee mechanics that lead to ligament failure. Normal anatomy of the knee ligaments, pathologic conditions, and postsurgical appearances of the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, and posterolateral corner are described., (Copyright © 2013 Wiley Periodicals, Inc.)

Rationale and Objectives: To evaluate the potential of high-pitch, dual-source computed tomography (DSCT) for compensation of motion artifacts., Materials and Methods: Motion artifacts were created using a moving chest/cardiac phantom with integrated stents at different velocities (from 0 to 4-6 cm/s) parallel (z direction), transverse (x direction), and diagonal (x and z direction combined) to the scanning direction using standard-pitch (SP) (pitch = 1) and high-pitch (HP) (pitch = 3.2) 128-detector DSCT (Siemens, Healthcare, Forchheim, Germany). The scanning parameters were (SP/HP): tube voltage, 120 kV/120 kV; effective tube current time product, 300 mAs/500 mAs; and a pitch of 1/3.2. Motion artifacts were analyzed in terms of subjective image quality and object distortion. Image quality was rated by two blinded, independent observers using a 4-point scoring system (1, excellent; 2, good with minor object distortion or blurring; 3, diagnostically partially not acceptable; and 4, diagnostically not acceptable image quality). Object distortion was assessed by the measured changes of the object's outer diameter (x) and length (z) and a corresponding calculated distortion vector (d) (d = √(x(2) + z(2)))., Results: The interobserver agreement was excellent (k = 0.91). Image quality using SP was diagnostically not acceptable with any motion in x direction (scores 3 and 4), in contrast to HP DSCT where it remained diagnostic up to 2 cm/s (scores 1 and 2). For motion in the z direction only, image quality remained diagnostic for SP and HP DSCT (scores 1 and 2). Changes of the object's diameter (x), length (z), and distortion vectors (d) were significantly greater with SP (overall: x = 1.9 cm ± 1.7 cm, z = 0.6 cm ± 0.8 cm, and d = 1.4 cm ± 1.5 cm) compared to HP DSCT (overall: x = 0.1 cm ± 0.1 cm, z = 0.0 cm ± 0.1 cm, and d = 0.1 cm ± 0.1 cm; each P < .05)., Conclusion: High-pitch DSCT significantly decreases motion artifacts in various directions and improves image quality., (Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.)

Because of its inherent superior soft tissue contrast and lack of ionizing radiation, magnetic resonance imaging (MRI) is highly suited to study the complex anatomy of the shoulder joint, particularly when assessing the relatively high incidence of shoulder injuries in young, athletic patients. This review aims to serve as a primer for understanding shoulder MRI in an algorithmical approach, including MRI protocol and technique, normal anatomy and anatomical variations of the shoulder, pathologic conditions of the rotator cuff tendons and muscles, the long head of the biceps tendon, shoulder impingement, labral and glenohumeral ligament pathology, MR findings in shoulder instability, adhesive capsulitis, and osteoarthritis.