As fast as an X-ray: real-time magnetic resonance imaging for diagnosis of idiopathic scoliosis in children and adolescents.

BACKGROUND: Idiopathic scoliosis is common in adolescence. Due to the rapid growth of the spine, it must be monitored closely with radiographs to ensure timely intervention when therapy is needed. As these radiographs continue into young adulthood, patients are repeatedly exposed to ionizing radiation. OBJECTIVE: This study aimed to investigate whether real-time magnetic resonance imaging (MRI) is equivalent to conventional radiography in juvenile idiopathic scoliosis for determining curvature, rotation and the Risser stage. Additionally, the time requirement should be quantified. MATERIALS AND METHODS: Children with idiopathic scoliosis who had postero-anterior whole-spine radiography for clinical indications were included in this prospective study. A real-time spine MRI was performed at 3 tesla in the supine position, capturing images in both the coronal and sagittal planes. The scoliosis was assessed using Cobb angle, rotation was evaluated based on Nash and Moe criteria, and the Risser stage was determined for each modality. The correlations between modalities and a correction factor for the Cobb angle between the standing and supine position were calculated. RESULTS: A total of 33 children (aged 5-17 years), who met the inclusion criteria, were recruited. The Cobb angle (R2 = 0.972; P < 0.01) was positively correlated with a correction factor of 1.07 between modalities. Additionally, the degree of rotation (R2 = 0.92; P < 0.01) and the Risser stage (R2 = 0.93; P < 0.01) demonstrated a strong correlation. CONCLUSION: Real-time MRI is equivalent to conventional radiography in determining baseline parameters. Furthermore, it is radiation-free and less time-consuming.

Influence of a Modified Procedure of Joining Ceramic Head and Adapter Sleeve on the Stem Taper in Revision: An Experimental Study.

In revision operations, ceramic heads of modular hip implants can be replaced. As the surface of the stem taper can be damaged, additional adapter sleeves are applied. The components are usually connected manually by the surgeon in a one-step procedure by hammer impacts. In this study, we investigated a two-step joining procedure with reproducible impaction force. First, the adapter sleeve and head were joined quasi-statically with a force of 2 kN using an assembly device. In the second step, these components were applied to the stem taper using a pulse-controlled instrument. For reference, the joints were assembled according to standard conditions using a tensile testing machine. An average pull-off force of 1309 ± 201 N was achieved for the components joined by the instrument, and the average measured values for the components joined by the testing machine were 1290 ± 140 N. All specimens achieved a force >350 N when released and therefore met the acceptance criterion defined for this study. This study showed that a modified procedure in two steps with a defined force has a positive effect on the reproducibility of the measured joining forces compared to previous studies.

Feasibility of a Shape-Memory-Alloy-Actuator System for Modular Acetabular Cups.

Hip implants have a modular structure which enables patient-specific adaptation but also revision of worn or damaged friction partners without compromising the implant-bone connection. To reduce complications during the extraction of ceramic inlays, this work presents a new approach of a shape-memory-alloy-actuator which enables the loosening of ceramic inlays from acetabular hip cups without ceramic chipping or damaging the metal cup. This technical in vitro study exam-ines two principles of heating currents and hot water for thermal activation of the shape-memory-alloy-actuator to generate a force between the metal cup and the ceramic inlay. Mechanical tests concerning push-in and push-out forces, deformation of the acetabular cup according to international test standards, and force generated by the actuator were generated to prove the feasibility of this new approach to ceramic inlay revision. The required disassembly force for a modular acetabular device achieved an average value of 602 N after static and 713 N after cyclic loading. The actuator can provide a push-out force up to 1951 N. In addition, it is shown that the necessary modifications to the implant modules for the implementation of the shape-memory-actuator-system do not result in any change in the mechanical properties compared to conventional systems.

The validity of the distress thermometer in patients with musculoskeletal tumors.

Background: Visits to an outpatient cancer clinic represent a challenging situation for patients, which can trigger anxiety and helplessness in those affected. It is important to identify patients with high psychological distress as early as possible in order to provide them with supportive psychological interventions. The aim of this study was to validate the Distress Thermometer (DT), a widely used screening for distress, in a cohort of patients with musculoskeletal tumors and to explore associations between distress, treatment satisfaction and health literacy. Methods: All patients presenting to a University outpatient clinic for musculoskeletal cancers were asked to complete a set of questionnaires including the DT), the Hospital Anxiety and Depression Scale (HADS) as a comparison scale, the Patient Satisfaction with Comprehensive Cancer Care (SCCC) and European Health Literacy Survey Questionnaire (HLS-EU-Q16).To assess the sensitivity and specificity of the DT in a cohort of patients with musculoskeletal tumors, we compare the performance of the DT in relation to an established screener for anxiety and depression using receiver operating characteristics (ROC) analyses. Results: A total of 120 patients (age 58 ± 18, 51% female) were analyzed. Patients reported a mean DT of 5.0 (SD 2.3, range, 0 to 10). Eighty-six patients (71.7 %) had a DT score ≥ 5 indicating moderate or severe psychological distress.The mean total HADS score (scale 0 to42 points) was 11.7 (SD 7.6, range, 0 to 32) with a HADS score of ≥ 15 in 29.2% of patients. The DT correlated moderately with anxiety and depression (HADS total r = 0.48, p < 0.001), while the correlation with depression (HADS-D, r = 0.47, p < 0.001) was stronger than with anxiety (HADS-A, r = 0.38, p < 0.001).For a DT score ≥ 5, ROC analysis yielded a sensitivity of 71.4% and a specificity of 75.3% for detecting moderate or severe psychological distress (HADS ≥ 15, AUC 0.782).The REPERES-G, collected from a subgroup (n = 49), showed high treatment satisfaction with a median score of 132 (min 90, max 163). Especially the "satisfaction with medical aspects of treatment" (REPERES-G medical aspects) showed a moderate correlation with the DT (r = 0.51, p < 0.001) a strong correlation with anxiety and depression (HADS total, r = 0.69, p < 0.001). Conclusion: About three in four patients with musculoskeletal tumors have relevant psychological distress. A visual analogue scale can only be a rough guide for identifying patients in need of psychological support, with a sensitivity of 71.4 % and a specificity of 75.3 %. A strong relationship between patient and care team was associated with lower patient psychological distress.Consequently, screening tools cannot replace detailed discussion and personal contact, especially in the treatment of malignant diseases.

Evaluating the Feasibility and Reproducibility of a Novel Insertion Method for Modular Acetabular Ceramic Liners.

Modern hip implants have a modular design. In case of wear or other damage it allows surgeons to change the tribological partners, i.e., the acetabular liner and femoral ball. In both revision and primary surgery, the secure joining of the implant components is important for the success of the operation. The two components, namely the ceramic liner and hip cup, are connected via a conical press connection and should be concentrically aligned to avoid chipping. Malseated liners can reduce the life span in situ. The amount of the joining force, which is usually applied via a hammer, depends on the surgeon. In this study, an alternative joining method for acetabular ceramic liners in hip cups was investigated, which intends to make the process more reproducible and thus safer. For this purpose, a handpiece was used to apply a defined force impulse of 4 kN. For the concentric alignment of a ceramic liner in the hip cup, an adapter was developed based on findings via a qualitative finite element (FE) analysis. Insertion and pushout tests of the acetabular cup-liner connection were performed in the laboratory with the new instrument (handpiece with the connected adapter) to evaluate the functionality of the instrument and the reproducibility of the new insertion method. For comparison, liners and acetabular cups were joined using a testing machine according to the standard. The presented results demonstrate the technical proof-of-concept of the new joining method under laboratory conditions. They meet the acceptance criteria of established manufacturers, which proves the equivalency to proven methods for joining modular implant components. To verify the improvement of the new joining method compared to the conventionally used joining method, an application-oriented study with different surgeons and the new joining instrument under clinical conditions is necessary.

Improving Home-Based Scoliosis Therapy: Findings From a Web-Based Survey.

BACKGROUND: Conservative scoliosis therapy in the form of assisted physiotherapeutic scoliosis exercises is supplemented by self-contained training at home, depending on the approach (eg, Schroth, the Scientific Exercises Approach to Scoliosis). Complex exercises, lack of awareness of the importance of training, and missing supervision by therapists often lead to uncertainty and reduced motivation, which in turn reduces the success of home-based therapy. Increasing digitalization in the health care sector offers opportunities to close this gap. However, research is needed to analyze the requirements and translate the potential of digital tools into concrete solution concepts. OBJECTIVE: The aim of this study is to evaluate the potential for optimizing home-based scoliosis therapy in terms of motivation, assistive devices, and digital tools. METHODS: In collaboration with the Institute of Physiotherapy at the Jena University Hospital, a survey was initiated to address patients with scoliosis and physical therapists. A digital questionnaire was created for each target group and distributed via physiotherapies, scoliosis forums, the Bundesverband für Skoliose Selbsthilfe e. V. newsletter via a link, and a quick response code. The survey collected data on demographics, therapy, exercise habits, motivation, assistive devices, and digital tools. Descriptive statistics were used for evaluation. RESULTS: Of 141 survey participants, 72 (51.1%; n=62, 86.1%, female; n=10, 13.9%, male) patients with scoliosis with an average age of 40 (SD 17.08) years and 30 scoliosis therapists completed the respective questionnaires. The analysis of home-based therapy showed that patients with scoliosis exercise less per week (2 times or less; 45/72, 62.5%) than they are recommended to do by therapists (at least 3 times; 53/72, 73.6%). Patients indicated that their motivation could be increased by practicing together with friends and acquaintances (54/72, 75%), a supporting therapy device (48/72, 66.7%), or a digital profile (46/72, 63.9%). The most important assistive devices, which are comparatively rarely used in home-based therapy, included balance boards (20/72, 27.8%), wall bars (23/72, 31.9%), mirrors (36/72, 50%), and long bars (40/72, 55.6%). Therapists saw the greatest benefit of digital tools for scoliosis therapy in increasing motivation (26/30, 87%), improving home therapy (25/30, 83%), monitoring therapy progress (25/30, 83%), and demonstrating exercise instructions (24/30, 80%). CONCLUSIONS: In this study, we investigated whether there is any potential for improvement in home-based scoliosis therapy. For this purpose, using online questionnaires, we asked patients with scoliosis and therapists questions about the following topics: exercise habits, outpatient and home-based therapy, motivation, supportive devices, and digital tools. The results showed that a lack of motivation, suitable training equipment, and tools for self-control leads to a low training workload. From the perspective of the patients surveyed, this problem can be addressed through community training with friends or acquaintances, a supportive therapy device, and digital elements, such as apps, with training instructions and user profiles.

Approach to standardized material characterization of the human lumbopelvic system-Specification, preparation and storage.

The complexity of the osseo-ligamentous lumbopelvic system has made it difficult to perform both, the overall preparation as well as specimen harvesting and material testing with a reasonable amount of time and personnel. The logistics of such studies present a hurdle for reproducibility. A structured procedure was developed and proved, which allows all necessary steps to be carried out reproducibly and in a reasonable time. This enables the extraction of 26 soft tissue, 33 trabecular and 32 cortical bone specimens from this anatomical region per cadaver. The integrity of the specimens remains maintained while keeping requirements within manageable limits. The practicability of the intended five-day specimen harvesting and testing procedure could be demonstrated on five test and two pre-test sequences. The intended minimization of physical, biological, and chemical external influences on specimens could be achieved. All protocols, instructions and models of preparation and storage devices are included in the supporting information. The high grade of applicability and reproducibility will lead to better comparability between different biomechanical investigations. This procedure proven on the human pelvis is transferable to other anatomical regions.

Approach for Non-Intrusive Detection of the Fit of Orthopaedic Devices Based on Vibrational Data.

The soft tissues of residual limb amputees are subject to large volume fluctuations over the course of a day. Volume fluctuations in residual limbs can lead to local pressure marks, causing discomfort, pain and rejection of prostheses. Existing methods for measuring interface stress encounter several limitations. A major problem is that the measurement instrumentation is applied in the sensitive interface between the prosthesis and residual limb. This paper presents the principle investigation of a non-intrusive technique to evaluate the fit of orthopaedic prosthesis sockets in transfemoral amputees based on experimentally obtained vibrational data. The proposed approach is based on changes in the dynamical behaviour detectable at the outer surface of prostheses; thus, the described interface is not affected. Based on the experimental investigations shown and the derived results, it can be concluded that structural dynamic measurements are a promising non-intrusive technique to evaluate the fit of orthopaedic prosthesis sockets in transfemoral amputee patients. The obtained resonance frequency changes of 2% are a good indicator of successful applicabilityas these changes can be detected without the need for complex measurement devices.

Virtual versus in-person multidisciplinary musculoskeletal tumor conferences in times of COVID-19.

Introduction: Multidisciplinary tumor conferences are a fundamental component in the treatment of oncological patients. The COVID-19 pandemic and its resulting social distancing restrictions offered the opportunity to compare in-person to virtual multidisciplinary tumor conferences. Methods: Retrospective analysis of first-time presentations in tumor conferences at a university musculoskeletal tumor center in the time periods from September 2019 to February 2020 (in-person) and May 2020 to October 2020 (virtual). Results: A total of 209 patients were first-time discussed in one of 52 analyzed musculoskeletal multidisciplinary tumor conferences (105 patients in 25 in-person, and 104 patients 27 virtual meetings). The total number of participants was slightly lower with virtual meetings (p < .001) and more disciplines were represented in virtual tumor conferences (p < .001). With median six consultants present in either, the level of available expertise did not differ between the conference formats (p = .606). Compared to in-person tumor meetings, the patients were discussed earlier in the virtual conferences (p = .028). The interval between first presentation to biopsy was significantly shorter after virtual tumor conferences (median 4 vs. 7 days, p < .001). There was no significant difference in the interval between initial presentation and resection (p = .544) among the two conference formats. Conclusions: The implementation of virtual tumor conferences appears to have had a positive effect on timely diagnosis and multidisciplinarity during tumor conferences. This may result in better decision-making and treatment of patients with musculoskeletal tumors and could be routinely implemented into cancer care.

Biomechanical comparative study of midline cortical vs. traditional pedicle screw trajectory in osteoporotic bone.

INTRODUCTION: In lumbar spinal stabilization pedicle screws are used as standard. However, especially in osteoporosis, screw anchorage is a problem. Cortical bone trajectory (CBT) is an alternative technique designed to increase stability without the use of cement. In this regard, comparative studies showed biomechanical superiority of the MC (midline cortical bone trajectory) technique with longer cortical progression over the CBT technique. The aim of this biomechanical study was to comparatively investigate the MC technique against the not cemented pedicle screws (TT) in terms of their pullout forces and anchorage properties during sagittal cyclic loading according to the ASTM F1717 test. METHODS: Five cadavers (L1 to L5), whose mean age was 83.3 ± 9.9 years and mean T Score of -3.92 ± 0.38, were dissected and the vertebral bodies embedded in polyurethane casting resin. Then, one screw was randomly inserted into each vertebra using a template according to the MC technique and a second one was inserted by freehand technique with traditional trajectory (TT). The screws were quasi-static extracted from vertebrae L1 and L3, while for L2, L4 and L5 they were first tested dynamically according to ASTM standard F1717 (10,000 cycles at 1 Hz between 10 and 110 N) and then quasi-static extracted. In order to determine possible screw loosening, there movements were recorded during the dynamic tests using an optical measurement system. RESULTS: The pull-out tests show a higher pull-out strength for the MC technique of 555.4 ± 237.0 N compared to the TT technique 448.8 ± 303.2 N. During the dynamic tests (L2, L4, L5), 8 out of the 15 TT screws became loose before completing 10,000 cycles. In contrast, all 15 MC screws did not exceed the termination criterion and were thus able to complete the full test procedure. For the runners, the optical measurement showed greater relative movement of the TT variant compared to the MC variant. The pull-out tests also revealed that the MC variant had a higher pull-out strength, measuring at766.7 ± 385.4 N, while the TT variant measured 637.4 ± 435.6 N. CONCLUSION: The highest pullout forces were achieved by the MC technique. The main difference between the techniques was observed in the dynamic measurements, where the MC technique exhibited superior primary stability compared to the conventional technique in terms of primary stability. Overall, the MC technique in combination with template-guided insertion represents the best alternative for anchoring screws in osteoporotic bone without cement.

Cervical spine fractures in ankylosing spondylitis patients: an analysis of the presentation and clinical results of 110 surgically managed patients in two spine centers.

PURPOSE: In this work, a two-center study was performed to study the clinical presentation of cervical spine fractures in ankylosing spondylitis (AS) patients and assess the surgical management of these fractures. METHODS: A retrospective analysis of prospectively collected data in two level-1 spine surgery centers was performed. Both spine centers have a standard database for all admitted patients. Inclusion criteria were surgically treated AS with cervical spine fracture diagnosis (from C1 to Th3) and postoperative follow-up minimum of 12 months. RESULTS: One hundred ten patients (105 male/5 female) were included. The mean age was 62 ± 10 years. The mean time between trauma and surgery was 49 ± 42 days. There was a history of mild trauma in 72 patients (65.4%). The clinical presentation was a pain in all patients. Twenty-seven (24.6%) had a neurological deficit at admission. The most common fracture level was C6/7 in 63 patients (57.23%). The VAS was 7 ± 1, and NDI was 34 ± 8 in the preoperative assessment. The mean preoperative kyphosis angle was 48 ± 26° between C2 and C7. Positioning and preparing of the patients on the operation table took a mean of 57 ± 28 min. The surgical approach was dorsal in 59 patients (53.6%), combined in 45 patients (40.9%), and ventral in 6 patients (6,5%). The mean number of the fixed levels was 6 ± 2 levels. Intraoperative complications occurred in 9 patients (8.2%). Postoperative Cobb angle improved to a mean of 17 ± 9 degrees. Neurological improvement occurred in 20/27 patients. In 12 patients, the recovery was complete. The mean postoperative follow-up was 46 ± 18 months. VAS improved to 3 ± 1, and NDI improved to 14 ± 6 at the last postoperative visit. The improvement was clinically significant (p = 0.01 and 0.00, respectively). CONCLUSION: High suspicion of cervical spine fractures is necessary for patients with AS. CT and MRI images are necessary to rule out cervical spine fractures in AS patients, especially to detect occult fractures. Surgical treatment is safe, and the posterior approach with long-segment fusion is the approach of choice in this group of patients.

Does the use of epicutaneous vacuum-assisted closure after revision surgery on the spine reduce further wound revision surgery?

PURPOSE: This study aimed to investigate the effect of epicutaneous vacuum therapy on the rate of unplanned spinal wound revisions compared with conventional wound dressing. METHODS: This retrospective study included patients who underwent unplanned revision spine surgery after primary aseptic spine surgery who were treated at a level I spine centre between December 2011 and December 2019. Patients with revision surgery who required a further unplanned revision surgery during the inpatient stay were considered a treatment failure. The epicutaneous vacuum-assisted closure (Epi-VAC) therapy was the standard treatment method beginning in 2017 (the epi-VAC group). Before, conventional wound dressing was used (the control group (CG)). In addition, a one-to-one matched-pair comparison analysis was performed between both groups. RESULTS: Of 218 patients, 48 were in the epi-VAC group. The mean age was 65.1 years (epi-VAC 68.2 to CG 64.3 years (P = 0.085)), and the mean body mass index (BMI) was 28.2 kg/m2 (epi-VAC 29.4 to CG 27.9 kg/m2 (P = 0.16)). No significant differences in the treatment failure rate could be detected between the two groups (epi-VAC 25% to CG 22.4% (P = 0.7)). There was also no significant difference for the matched-pair analysis (epi-VAC 26.1% to CG 15.2% (P = 0.3)). An elevated CRP level (C-reactive protein) immediately before the first wound revision was a significant risk factor for further revision surgery (treatment failure: 135.2 ± 128.6; no treatment failure: 79.7 ± 86.1 mg/l (P < 0.05)). CONCLUSION: Concerning repeat unplanned wound revision after spinal revision surgery, we cannot demonstrate an advantage of the epicutaneous vacuum therapy over conventional wound dressing.

Imaging in the Diagnosis of Nonspecific Pyogenic Spondylodiskitis.

The prevalence of nonspecific pyogenic spondylodiskitis, associated with both a high morbidity and a high mortality, has increased in the last few decades. The diagnosis is often delayed because of the nonspecific clinical manifestation at the early stage. The reliability of radiographs is limited, particularly in early stage after the onset of infection. Computed tomography (CT) can reliably assess the bony condition with the possibility of spatial visualization. Contrast enhancement supports the detection of affected soft tissue. Magnetic resonance imaging (MRI) continues to be the gold standard in the diagnosis of spondylodiskitis. Sophisticated investigation protocols supported by gadolinium enhancement secure the diagnosis. MRI has a high resolution without radiation exposure. Different nuclear investigation techniques extend the diagnostic options. Reports of 18F-fluorodeoxyglucose-positron emission tomography (18-FDG-PET) are particularly promising to confirm the diagnosis. The drawback of the reduced image quality with respect to detailed anatomical information can be overcome by a combined simultaneous acquisition of CT or MRI. With respect to one of the greatest challenges, the differentiation between degenerative changes (Modic type 1) and infection at an early stage using differentiated MRI protocols and FDG-PET is promising. This overview presents a concise state-of-the-art look at radiologic investigations in case of suspected nonspecific pyogenic spondylodiskitis with the focus on a pragmatic approach.

Complications of injections in conservative treatment of degenerative spine disease: a prospective unicentric study.

BACKGROUND: Spinal injection has been an accepted part of conservative therapy for degenerative diseases. The drugs used can cause side effects and severe complications. The aim of this study was to determine the occurrence of general side effects (GSE) and complications when performing consecutive different types of spinal injections and to evaluate pain reduction. METHODS: Prospective data evaluation of patients with degenerative spine disease at hospital admission, discharge, and six and 12 weeks after discharge. All patients received a specific injection protocol depending on their symptoms and radiological findings. The injections performed were dorsal sacroiliac joint injections, perineural injections, epidural interlaminar and epidural periradicular injections, and facet joint injections. Potential complications were categorized and recorded as GSE and complications. In addition, the Numerical Analog Scale (NAS) for pain, the Oswestry Disability Index (ODI) were evaluated. RESULTS: Forty-eight patients were enrolled. There were 282 spinal injections performed. A total of 131 common treatment-related events were recorded. Depending on the type of injection, transient pain at the injection site (32.4-73.5%), radiating pain (9.4-34.7%), and nerve root irritation (2-18.4%) were the most common. One complication with postpuncture syndrome occurred with epidural-interlaminar injection. No persistent neurologic deficits occurred. The highest rate of GSE was observed with periradicular injections (relative frequency (RF) = 0.8), followed by epidural-interlaminar injections (RF = 0.65), least frequently with FJ injections (RF = 0.32). From the time of admission to discharge, NAS scores were significantly decreased and ODI score significantly improved at discharge (p < 0.001), but relapse occurred at the 12-week follow-up. CONCLUSIONS: Various consecutive spinal injections for conservative treatment of degenerative spine diseases are safe and lead to a decrease in pain and improvement in quality of life. GSE are common, but not persistent. Although complications are rare, they can have serious consequences for the patient.

Sacroiliac innervation.

PURPOSE: To investigate the innervation pattern of the sacroiliac region, especially with regard to the sacroiliac joint (SIJ). Dorsal SIJ innervation was analyzed and described. Our main hypothesis was that nerves reach the SIJ dorsally, passing ligamental compartments, as this would explain dorsal SIJ pain. METHODS: To examine sacroiliac innervation, we followed the nerves in over 50 specimens over several years. Plastinated slices were evaluated, nerves in the region were stained histologically, and the data were summarized as 3D models. RESULTS: The Rami communicans and posterior branches of the spinal nerves and their branches that form a dorsal sacral plexus and communicating branches, together with corresponding vessels, were observed to form neurovascular bundles embedded by tiny fatty connectives in gaps and tunnels. Branches of L5-S1 pass the inner sacroiliac ligaments (the interosseous sacroiliac ligament and axial interosseous ligament). The outer sacroiliac ligaments (posterior sacroiliac ligaments, long posterior sacroiliac ligament, sacrotuberal ligament, thoracolumbar fascia) are passed by the S1-S4 branches. However, although the paths of these nerves are in the direction of the SIJ, they do not reach it. It is possible that impingement of the neurovascular bundles may result in pain. Moreover, the gaps and tunnels connect to the open dorsal SIJ. CONCLUSION: Our findings suggest that Bogduk's term "sacroiliac pain" correlates to "sacroiliac innervation", which consists of "inner-" and "outer sacroiliac ligament innervation", and to ventral "SIJ pain". The watery gaps and tunnels observed could play a significant role in innervation and thus in the origins of SIJ pain. LEVEL OF EVIDENCE: Individual cross-sectional studies with consistently applied reference standard and blinding.

The sacrotuberous ligament is preloaded in situ.

The objective of this study was to evaluate the intrinsic preload of the sacrotuberous ligament. Preload measurements and anatomical experiments were performed on 20 specimens from 10 human cadavers and assessed to consider the thesis of the ligamentous tension band system as a possible load distribution. The result was an unexpectedly high preload force with an overall average of 118 N ± 74 N. Age has been significantly different between females and males in the cohort (median 94 vs. 77 years). Nevertheless, there is preliminary evidence of the sex-dependent sacrotuberous ligament preload force with an average value of approximately 65 N for the 10 female cadaver specimens and 172 N for the 10 male cadaver specimens. The assessment of further influencing factors and their statistical evaluation also showed a dependence of the sacrotuberous ligament preload force on body height, age and elastin content. Thus, the sacrotuberous ligament is more preloaded in the cadaver than previously assumed in the literature. Therefore, and contrary to most assumptions, it could possibly also be more preloaded in a living person in an upright position under a muscular load. This leads to the hypothesis that pelvic stability is more dependent on ligamentous preload than previously thought. These considerations should be taken more into account in numerical simulations of sacroiliac joint function.

Primary stability of multi-hole cups compared to plate osteosynthesis in osteoporotic anterior column and posterior hemi-transverse acetabular fractures-A biomechanical comparison.

INTRODUCTION: Acetabular fractures pose high demands on the surgeon and in the case of osteosynthetic treatment, anatomical reconstruction has the highest priority to achieve a good outcome. However, especially in older patients with poor bone quality, even anatomical reconstruction is no guarantee for a good clinical outcome and may nevertheless end in early osteoarthritis. Primary arthroplasty therefore has an increasing importance in the treatment of these patients. The aim of this study was to biomechanically compare fracture gap displacement and failure load as an assessment measure of the primary stability of conventional plate osteosynthesis with the treatment using a sole multi-hole cup for acetabular fractures. METHODS: Six hemi-pelvises each with anterior column and posterior hemi-transverse (ACPHT) fracture were treated with either plate osteosynthesis or a multi-hole cup. The tests were carried out in a standardised test set-up with cyclic loading in various stages between 150 N and 2500 N. The fracture gap displacement was recorded with optical 3D measuring and the failure load was determined after the cyclic measurement. RESULTS: With increasing force, the fracture gap displacement increased in both procedures. In each group there was one treatment which failed at the cyclic loading test and a bone fragment was broken out. The primary stability in arthroplasty was comparable to that of the standard osteosynthesis. CONCLUSIONS: The results found seem promising that the primary arthroplasty with a sole multi-hole cup and corresponding screw fixation achieves an initial stability comparable to osteosynthesis for typical ACPHT fractures. However, further clinical studies are needed to prove that the cups heal solidly into the bone.

Convolutional Neural Networks in Spinal Magnetic Resonance Imaging: A Systematic Review.

OBJECTIVE: Convolutional neural networks (CNNs) are being increasingly used in the medical field, especially for image recognition in high-resolution, large-volume data sets. The study represents the current state of research on the application of CNNs in image segmentation and pathology detection in spine magnetic resonance imaging. METHODS: For this systematic literature review, the authors performed a systematic initial search of the PubMed/Medline and Web of Science (Core collection) databases for eligible investigations. The authors limited the search to observational studies. Outcome parameters were analyzed according to the inclusion criteria and assigned to 3 groups: 1) segmentation of anatomical structures, 2) segmentation and evaluation of pathologic structures, and 3) specific implementation of CNNs. RESULTS: Twenty-four retrospectively designed articles met the inclusion criteria. Publication dates ranged from 2017 to 2021. In total, 14,065 patients with 113,110 analyzed images were included. Most authors trained their network with a training-to-testing ratio of 80/20, while all but 2 articles used 5- to 10-fold cross-validation. Nine articles compared their performance results with other neural networks and algorithms, and all 24 articles described outcomes as positive. CONCLUSIONS: State-of-the-art CNNs can detect and segment-specific anatomical landmarks and pathologies across a wide range, comparable to the skills of radiologists and experienced clinicians. With rapidly evolving network architectures and growing medical image databases, the future is likely to show growth in the development and refinement of these capable networks. However, the aid of automated segmentation and classification by neural networks cannot and should not be expected to replace clinical experts.

Degeneration of the lumbar spine and its relation to the expression of collagen and elastin in facet joint capsules and ligament flavum.

OBJECTIVE: The aim of the study was to assess the relationship between the expression of elastin, collagen type I, II,III and the degenera- tion of the facet joint capsule and the ligamentum flavum. METHODS: 10 patients (4 male, 6 female) (mean age 61 ± 14,9) undergoing surgery for degenerative lumbar spine syndrome and 5 cadav- ers (3 male, 2 female) (age of death 87 ± 8,6 years) were included in this study. One set of tissue samples was taken from each patient in the patient group intraoperatively and two sets of samples were taken from each cadaver in the cadaver group posthumosly from the ligamentum flavum (medial and lateral) and from the facet joint capsules (superior and inferior articular process) at the L4/5 segment. Western blot analysis was performed for collagen types I, II, III and for elastin. Disc degeneration was scored according to the Pfirmann Classification, facet joint arthrosis was scored according to the Fujiwara Classification and their relationship with protein expression was investigated. RESULTS: There was a strong expression of Collagen type I in the patient group (PG) compared to the body donor group (BDG) in the facet joint capsule (FJC) and in the lateral samples of the ligamentum flavum. Samples of the FJC showed lower expression of elastin in the PG compared with the BDG, but without statistical significance. An increased expression of collagen type I compared to elastin in the PG could be shown. In contrast, elastin predominated in the samples of the BDG group compared to collagen type I (collagen type I/ elastin PG: PAsup 2,78; PAinf 2,61; LFmed 2,23; 225 LFlat 1,83; BDG: PAsup 0,15; PAinf 0,2; LFmed 0,2; LFlat 0,27). Rank correlation coefficient according to Spearman showed low to moderate correlations for collagen type I, III and elastin for the degree of disc degeneration accord- ing to Pfirrmann and the degree of facet joint osteoarthritis according to Fujiwara, all of them without statistical significance. CONCLUSION: This study has shown us that in the context of degenerative changes of the lumbar spine, there is an increased expression of collagen type I and a dominance over elastin. LEVEL OF EVIDENCE: Level III, Diagnostic Study.