Is It Possible to Replace Conventional Radiography (CR) with a Dose Neutral Computed Tomography (CT) of the Cervical Spine in Emergency Radiology-An Experimental Cadaver Study.

The purpose of this experimental study on recently deceased human cadavers was to investigate whether (I) the radiation exposure of the cervical spine CT can be reduced comparable to a dose level of conventional radiography (CR); and (II) whether and which human body parameters can be predictive for higher dose reduction potential (in this context). MATERIALS AND METHODS: Seventy serial CT scans of the cervical spine of 10 human cadavers undergoing postmortem virtual autopsy were taken using stepwise decreasing upper limits of the tube current (300 mAs, 150 mAs, 110 mAs, 80 mAs, 60 mAs, 40 mAs, and 20 mAs) at 120 kVp. An additional scan acquired at a fixed tube current of 300 mAs served as a reference. Images were reconstructed with filtered back projection and the upper (C1-4) and lower (C4-7) cervical spine were evaluated by three blinded readers for image quality, regarding diagnostic value and resolution of anatomical structures according to a semiquantitative three-point-scale. Dose values and individual physical parameters were recorded. The relationship of diagnostic IQ, dose reduction level, and patients' physical parameters were investigated. The high-contrast resolution of the applied CT protocols was tested in an additional phantom study. RESULTS: The IQ of the upper cervical spine was diagnostic at 1.69 ± 0.58 mGy (CTDI) corresponding to 0.20 ± 0.07 mSv (effective dose) in all cadavers. IQ of the lower cervical spine was diagnostic at 4.77 ± 1.86 mGy corresponding to 0.560 ± 0.21 mSv (effective dose) in seven cadavers and at 2.60 ± 0.93 mGy corresponding to 0.31 ± 0.11 mSv in four cadavers. Significant correlation was detected for BMI (0.8366; p = 0.002548) and the anteroposterior (a.p.) chest diameter (0.8363; p = 0.002566), shoulder positioning (0.79799; p = 0.00995), and radiation exposure. CONCLUSIONS: Conventional radiography can be replaced with a nearly dose-neutral CT scan of the cervical spine.

Curriculum learning for improved femur fracture classification: Scheduling data with prior knowledge and uncertainty.

An adequate classification of proximal femur fractures from X-ray images is crucial for the treatment choice and the patients' clinical outcome. We rely on the commonly used AO system, which describes a hierarchical knowledge tree classifying the images into types and subtypes according to the fracture's location and complexity. In this paper, we propose a method for the automatic classification of proximal femur fractures into 3 and 7 AO classes based on a Convolutional Neural Network (CNN). As it is known, CNNs need large and representative datasets with reliable labels, which are hard to collect for the application at hand. In this paper, we design a curriculum learning (CL) approach that improves over the basic CNNs performance under such conditions. Our novel formulation reunites three curriculum strategies: individually weighting training samples, reordering the training set, and sampling subsets of data. The core of these strategies is a scoring function ranking the training samples. We define two novel scoring functions: one from domain-specific prior knowledge and an original self-paced uncertainty score. We perform experiments on a clinical dataset of proximal femur radiographs. The curriculum improves proximal femur fracture classification up to the performance of experienced trauma surgeons. The best curriculum method reorders the training set based on prior knowledge resulting into a classification improvement of 15%. Using the publicly available MNIST dataset, we further discuss and demonstrate the benefits of our unified CL formulation for three controlled and challenging digit recognition scenarios: with limited amounts of data, under class-imbalance, and in the presence of label noise. The code of our work is available at: https://github.com/ameliajimenez/curriculum-learning-prior-uncertainty.

Chronic active non-lethal human-type tuberculosis in a high royal Bavarian officer of Napoleonic times-a mummy study.

In paleopathology, morphological and molecular evidence for infection by mycobacteria of the M. tuberculosis complex (MTC) is frequently associated with early death. In the present report, we describe a multidisciplinary study of a well-preserved mummy from Napoleonic times with a long-standing tuberculous infection by M. tuberculosis senso stricto who died at the age of 88 years of focal and non-MTB related bronchopneumonia. The well-preserved natural mummy of the Royal Bavarian General, Count Heinrich LII Reuss-Köstritz (1763-1851 CE), was extensively investigated by macro- and histomorphology, whole body CT scans and organ radiography, various molecular tissue analyses, including stable isotope analysis and molecular genetic tests. We identified signs for a long-standing, but terminally inactive pulmonary tuberculosis, tuberculous destruction of the second lumbar vertebral body, and a large tuberculous abscess in the right (retroperitoneal) psoas region (a cold abscess). This cold abscess harboured an active tuberculous infection as evidenced by histological and molecular tests. Radiological and histological analysis further revealed extensive arteriosclerosis with (non-obliterating) coronary and significant carotid arteriosclerosis, healthy bone tissue without evidence of age-related osteopenia, evidence for diffuse idiopathic skeletal hyperostosis and mild osteoarthrosis of few joints. This suggests excellent living conditions correlating well with his diet indicated by stable isotope results and literary evidence. Despite the clear evidence of a tuberculous cold abscess with bacterioscopic and molecular proof for a persisting MTC infection of a human-type M. tuberculosis strain, we can exclude the chronic MTC infection as cause of death. The detection of MTC in historic individuals should therefore be interpreted with great caution and include further data, such as their nutritional status.

Precise proximal femur fracture classification for interactive training and surgical planning.

PURPOSE: Demonstrate the feasibility of a fully automatic computer-aided diagnosis (CAD) tool, based on deep learning, that localizes and classifies proximal femur fractures on X-ray images according to the AO classification. The proposed framework aims to improve patient treatment planning and provide support for the training of trauma surgeon residents. MATERIAL AND METHODS: A database of 1347 clinical radiographic studies was collected. Radiologists and trauma surgeons annotated all fractures with bounding boxes and provided a classification according to the AO standard. In all experiments, the dataset was split patient-wise in three with the ratio 70%:10%:20% to build the training, validation and test sets, respectively. ResNet-50 and AlexNet architectures were implemented as deep learning classification and localization models, respectively. Accuracy, precision, recall and [Formula: see text]-score were reported as classification metrics. Retrieval of similar cases was evaluated in terms of precision and recall. RESULTS: The proposed CAD tool for the classification of radiographs into types "A," "B" and "not-fractured" reaches a [Formula: see text]-score of 87% and AUC of 0.95. When classifying fractures versus not-fractured cases it improves up to 94% and 0.98. Prior localization of the fracture results in an improvement with respect to full-image classification. In total, 100% of the predicted centers of the region of interest are contained in the manually provided bounding boxes. The system retrieves on average 9 relevant images (from the same class) out of 10 cases. CONCLUSION: Our CAD scheme localizes, detects and further classifies proximal femur fractures achieving results comparable to expert-level and state-of-the-art performance. Our auxiliary localization model was highly accurate predicting the region of interest in the radiograph. We further investigated several strategies of verification for its adoption into the daily clinical routine. A sensitivity analysis of the size of the ROI and image retrieval as a clinical use case were presented.

Injuries of the isolated larynx-hyoid complex in post-mortem computed tomography (PMCT) and post-mortem fine preparation (PMFP) - a comparison of 54 forensic cases.

OBJECTIVES: To assess the diagnostic accuracy (ACC) of post-mortem computed tomography (PMCT) for fractures of the isolated larynx-hyoid complex (LHC) in comparison to post-mortem fine preparation (PMFP). METHODS: This monocentric prospective study enclosed 54 LHCs that were extracted during autopsy, fixed in formalin, and underwent a PMCT scan (64-row multidetector CT, helical pitch). Two radiologists independently analyzed the LHC scans for image quality (IQ) and fractures (4-point Likert scales). A specialized forensic preparator dissected the specimens under the stereomicroscope. The PMFP results were standardized documented, and used as the standard of reference for the comparison to PMCT. RESULTS: The PMCT-IQ of 95% of the LHC images was rated as good or excellent. IQ was decreased by decay, incisions during autopsy, and separation of the hyoid from the cartilaginous components in 7, 3, and 12 specimens, respectively. PMFP detected 119 fractures in 34 LHCs (63.0%). PMCT identified 91 fractures in 32 specimens (59.3%). PMFP and PMCT significantly agreed concerning the location (Cohen's κ = 0.762; p < 0.001) and the degree of dislocation (κ = 0.689; p < 0.001) of the fractures. Comparing PMCT to PMFP resulted in a sensitivity of 88.2%, a specificity of 90.0%, and an ACC of 88.9% for the LHC. The ACCs for the hyoid, thyroid, and cricoid were 94.4%, 87.0%, and 81.5%, respectively. PMCT procedure was significantly faster than PMFP (28.9 ± 4.1 min vs. 208.2 ± 32.5 min; p < 0,001). CONCLUSIONS: PMCT can detect distinct injuries of the isolated LHC and may promptly confirm violence against the neck as cause of death. PMFP outmatches PMCT in the detection of decent injuries like tears of the cricoid cartilage. KEY POINTS: • Post-mortem computed tomography is able to assess fractures of the larynx-hyoid complex. • Prospective monocentric in vitro study showed that post-mortem computed tomography of the larynx-hyoid complex is faster than post-mortem fine preparation. • Post-mortem computed tomography can confirm violence against the neck as cause of death.

Intraosseous needles in pediatric cadavers: Rate of malposition.

AIM OF THE STUDY: Intraosseous vascular access is a commonly conducted procedure especially in pediatric resuscitation. Very high success rates for intraosseous (IO) devices are reported. Aim of the study was to describe the rates of malposition of intraosseous needles (ION) in pediatric cadavers via post-mortem computed tomography (PMCT). METHODS: 212 consecutive pediatric cadavers underwent PMCT, of which 38 cadavers had visible ION and were included in the study. They were divided into two subgroups depending on their age (n = 22 infant cadavers (age <1 year) and n = 16 child cadavers (age ≥1 year)). Two independent readers evaluated the number and position of ION. RESULTS: In 22 infant cadavers 34 ION were found. Malposition of at least one ION was visible in 14 subjects (64%), among which 7 cadavers (32%) even had no correctly placed ION, thus being without established vascular access. Overall, 16 of the 34 used ION devices (47%) were in malposition. 23 ION were found in 16 child cadavers. In 8 subjects (50%) at least one ION was malpositioned, among which 3 cadavers (19%) had no correctly placed ION, resulting in a complete absence of vascular access. Overall, 9 of the 23 ION devices (39%) were malpositioned. CONCLUSION: Our study showed relatively high malposition rates for ION devices in pediatric cadavers which was not to be assumed regarding the success rates of 80% and higher in previous literature. This should be clarified by further studies in living patients.

Potential accuracy of navigated K-wire guided supra-acetabular osteotomies in orthopedic surgery: a CT fluoroscopy cadaver study.

BACKGROUND: The aim of this study was to evaluate the accuracy of supra-acetabular pelvic tumor resections in human, full-body cadavers and under realistic operation room conditions with the help of a navigation system and K-wires as guidance for the oscillating saw. METHODS: Seven hemipelvises from fresh, human, male, full-body cadavers were used. A preoperative and a postoperative CT was performed. Under control of the navigation system K-wires were inserted and served as guidance for the oscillating saw to reduce the error by vibration and jerking movements. The accuracy of the computer aided resections was compared with the accuracy of freehand resections in customized 3D printed pelvises with geometries identical to the cadavers used. RESULTS: The mean deviation of the navigated osteotomies was 1.9 mm (standard deviation 1.0 mm) significantly (P < 0.001) lower than the mean deviation of freehand osteotomies at 9.2 mm (standard deviation 3.7 mm). CONCLUSION: Navigated K-wires for supra-acetabular osteotomies allow significantly higher accuracy than freehand procedures under simulated operation room conditions. Copyright © 2016 John Wiley & Sons, Ltd.

Analysis of death in major trauma: value of prompt post mortem computed tomography (pmCT) in comparison to office hour autopsy.

BACKGROUND: To analyze diagnostic accuracy of prompt post mortem Computed Tomography (pmCT) in determining causes of death in patients who died during trauma room management and to compare the results to gold standard autopsy during office hours. METHODS: Multiple injured patients who died during trauma room care were enrolled. PmCT was performed immediately followed by autopsy during office hours. PmCT and autopsy were analyzed primarily regarding pmCT ability to find causes of death and secondarily to define exact causes of death including accurate anatomic localizations. For the secondary analysis data was divided in group-I with equal results of pmCT and autopsy, group-II with autopsy providing superior results and group-III with pmCT providing superior information contributing to but not majorly causing death. RESULTS: Seventeen multiple trauma patients were enrolled. Since multiple trauma patients were enrolled more injuries than patients are provided. Eight patients sustained deadly head injuries (47.1%), 11 chest (64.7%), 4 skeletal system (23.5%) injuries and one patient drowned (5.8%). Primary analysis revealed in 16/17 patients (94.1%) causes of death in accordance with autopsy. Secondary analysis revealed in 9/17 cases (group-I) good agreement of autopsy and pmCT. In seven cases autopsy provided superior results (group-II) whereas in 1 case pmCT found more information (group-III). DISCUSSION: The presented work studied the diagnostic value of pmCT in defining causes of death in comparison to standard autopsy. Primary analysis revealed that in 94.1% of cases pmCT was able to define causes of death even if only indirect signs were present. Secondary analysis showed that pmCT and autopsy showed equal results regarding causes of death in 52.9%. CONCLUSIONS: PmCT is useful in traumatic death allowing for an immediate identification of causes of death and providing detailed information on bony lesions, brain injuries and gas formations. It is advisable to conduct pmCT especially in cases without consent to autopsy to gain information about possible causes of death and to rule out possible clinical errors.

Dynamic quantification of tibio-femoral rotation in postero-lateral bundle insufficiency of the anterior cruciate ligament: a cadaver study.

PURPOSE: Anterior cruciate ligament (ACL) injury represents one of the most common diagnoses in orthopaedic sports medicine. In the past, anatomic knowledge about the different bundles within the cruciate ligaments triggered new treatment concepts, such as double-bundle ACL reconstruction. Recently, besides complete tearing, partial ACL ruptures and bundle augmentation became a focus. However, only little is known regarding rotational stability of the knee with an isolated torn postero-lateral (PL) bundle. Therefore, the aim of the present study was the torsiometric analysis of tibio-femoral restraint patterns of the PL-insufficient knee joint. METHODS: Fresh human whole body cadavers were enrolled. After diagnostic arthroscopy to ensure the structural integrity of the cruciate ligaments, knee joints underwent torsiometry at 0°, 30°, and 90° degree flexion. Then stepwise the PL bundle and the anteromedial (AM) bundle were arthroscopically resected, while torsiometry of the PL- as well as of the ACL-deficient knee joints was repeated. An area under the curve (AUC) was calculated. All statistical analyses were conducted using a p-value of 0.05 as level of significance. RESULTS: The comparison of charged and equilibrated curves during internal rotation revealed significant results at low flexion (30° flexion) angles between the ACL intact versus PL absent conditions (p = 0.04). In addition, charged and equilibrated curves during external rotation at 90° flexion, thus high angles, resulted in a significant difference when comparing the ACL-intact with the PL-deficient condition (p = 0.01). CONCLUSIONS: In the present cadaver study using the Torsiometer tool we found a distinct destabilization of the rotational restraints in full knee extension only after total ACL resection. In contrast, no significant findings resulted after an isolated dissection of the PL bundle during internal deflection. Nevertheless, a significant loss of stability was found during unstressed external deflection after isolated PL bundle dissection. Therefore patients, undergoing PL augmentation might benefit regarding rotational instability patterns.

The extent of changes in the membranous urethra angle is associated with the outcome of retrourethral transobturator sling procedure.

PURPOSE: To evaluate the outcome of the retrourethral transobturator sling (RTS) by functional magnetic resonance imaging (MRI) and to identify parameters associated with sling failure. METHODS: Of thirty recruited men with postprostatectomy stress urinary incontinence (SUI), 26 consecutively underwent functional MRI before sling procedure and 12 months thereafter in a prospective clinical cohort observational study. Periurethral/urethral fibrosis and sling visualization were evaluated on static sequences. The angle of the membranous urethra, position of the bladder neck and external urethral sphincter were assessed during Valsalva's maneuver and voiding. Sling success was defined as no or one dry "security" pad. RESULTS: The success and failure rates were 58 % (15/26 patients) and 42 % (11/26 patients), respectively. The sling leads to reduction in the membranous urethra angle during Valsalva's maneuver (39.55° vs. 36.82°, p = 0.025) and voiding (38.25° vs. 34.83°, p = 0.001) and elevation of the external urethral sphincter (2.9 vs. 4.8 mm, p = 0.017). Preoperative wider angle of the membranous urethra was significantly correlated with severe preoperative incontinence. Sling failure (p = 0.001) and severe preoperative incontinence (p = 0.001) were significantly related to only small changes of the membranous urethra angle. The interrater and intrarater reliability for membranous urethra angle was excellent (intraclass correlation coefficient ≥0.75). CONCLUSIONS: The RTS leads to reduction in the membranous urethra angle. The extent of the changes in the membranous urethra angle is associated with RTS outcome. Functional MRI is a reliable noninvasive visualization tool of interactions between the sling and pelvic floor for further research on the complex nature of postprostatectomy SUI.

Is a wider angle of the membranous urethra associated with incontinence after radical prostatectomy?

PURPOSE: To investigate whether differences in the anatomy and dynamics of the pelvic floor (PF) in patients after radical prostatectomy (RP) depicted on magnetic resonance imaging (MRI) are associated with continence status. METHODS: In the prospective designed study, 24 patients with post-prostatectomy stress urinary incontinence were enrolled. Additionally, 10 continent patients after RP were matched for age, body mass index and perioperative parameters. All patients underwent continence assessment and MRI (TrueFISP sequence; TR 4.57 ms; TE 2.29 ms; slice thickness 7 mm; FOV 270 mm) 12 months after RP. Images were analyzed for membranous urethra length (MUL), angle of the membranous urethra (AMU), severity of periurethral/urethral fibrosis, lifting of the levator ani muscle, lowering of the posterior bladder wall (BPW), bladder neck (BN) and external urinary sphincter (EUS), and symphyseal rotation of these structures during the Valsalva maneuver and voiding. RESULTS: Compared to continent controls, incontinent patients showed a significant wider AMU during voiding (p = 0.002) and more pronounced lowering of the BN and EUS (p < 0.001). No differences between the groups were found in symphyseal rotation of the analyzed structures, MUL and severity of periurethral/urethral fibrosis. CONCLUSIONS: The angle of the membranous urethra as a result of anchoring of the BN and EUS in the PF appears to be an important functional factor with an essential impact on continence after RP. Functional MRI seems to be a helpful imaging tool for morphologic and dynamic evaluation of the PF.

Mono- versus polyaxial locking plates in distal femur fractures: a prospective randomized multicentre clinical trial.

PURPOSE: Treatment of complex fractures of the distal femur utilizing monoaxial locking plates (e.g. Less Invasive Stabilisation System, LISS®, Synthes) is considered to be superior to conventional plating systems. Due to the limitation that the thread forces the screw into pre-determined positions, modifications have been made to allow screw positioning within a range of 30° (Non Contact Bridging, NCB®-DF, Zimmer). For the first time, this multicenter prospective randomized clinical trial (RCT) investigates the outcome of LISS® vs. NCB®-DF treatment following complex fractures of the distal femur. METHODS: Since June 2008, 27 patients with a fracture of the distal femur (AO ASIF 33-A-C and periprosthetic fractures) were enrolled in this study by four university trauma centres in southern Germany. Clinical (e.g. range of motion, Oxford knee score, Tegner score) and radiological (e.g. axis deviation, secondary loss of realignment) follow-ups were conducted one and six weeks, as well as three, six, and 12 months after the operation. RESULTS: This study comprises data of 27 patients (8 male, 19 female; 15 NCB®-DF, 12 LISS®). Polyaxial osteosynthesis using the NCB® system tended to result in better functional knee scores and a higher range of motion. Interestingly, fracture union tended to be more rapid using the polyaxial plating system. CONCLUSIONS: We present the analysis of a multicenter prospective RCT to compare the monoaxial LISS® vs. the polyaxial NCB®-DF treatment following complex fractures of the distal femur. NCB®-DF treatment tended to result in better functional and radiological outcomes than LISS® treatment. LEVEL OF EVIDENCE: Level I.

Significant benefit for older patients after arthroscopic subacromial decompression: a long-term follow-up study.

BACKGROUND: Patients suffering from isolated subacromial impingement (SI) of their shoulder but who are resistant to other therapies benefit substantially from arthroscopic subacromial decompression (ASD) if they are young (<60 years). Although physical demands rise notably in the older population, it still remains unclear if surgery leads to better results in these patients. Therefore, the aim of this study was to focus on the impact of age on the functional outcome in elderly patients suffering from SI. METHODS: In this retrospective analysis, 307 patients (age range: 42-63 years) with isolated SI were enrolled. The 165 patients were allocated to physical therapy whereas 142 underwent ASD. The patient cohort was divided into two groups according to the median age (<57 years). Functional outcome was recorded using the Munich Shoulder Questionnaire (MSQ) allowing for qualitative self -assessment of the Constant, SPADI and Dark Scores. RESULTS: Median age was 57 (25%-75%: 48-63) years, follow-up was 55 (25%-75%: 25-87) months. In group I (age < 57 years, n = 165) no significant differences in outcome between physical therapy and ASD were detected. In contrast, in group II (age > 57 years; n = 142) the patients reported significantly better results after ASD in the overall MSQs. CONCLUSION: Despite their higher age, elderly patients with isolated SI actually benefit significantly from ASD in comparison to physical therapy.

Morphology and dynamics of the male pelvic floor before and after retrourethral transobturator sling placement: first insight using MRI.

PURPOSE: We prospectively evaluated changes in morphology and dynamics of the male pelvic floor on magnetic resonance imaging (MRI) associated with retrourethral transobturator sling (RTS) placement. PATIENTS AND METHODS: Twenty-six men with post-prostatectomy incontinence consecutively underwent functional cine-MRI before and 12 months after RTS. The membranous urethra length (MUL) and severity of periurethral/urethral fibrosis were assessed on static MRI. A lowering of the posterior bladder wall (BPW), the bladder neck (BN), the external urinary sphincter (EUS) and symphysial rotation of these structures were analysed on dynamic MR images. The success rate was defined as cure (0-1 dry 'security' pad) or improvement (pad reduction ≥ 50 %). RESULTS: The success rate was 77 % (20/26 patients). The mean follow-up was 20.4 months. The MUL significantly increased post-operatively (p < 0.001). There were no significant pre- and post-operative differences in severity of periurethral/urethral fibrosis. Significant elevation of the BPW (p < 0.021), BN and EUS (p < 0.002) was observed post-operatively. The RTS failure was significantly associated with the severity of periurethral fibrosis pre- (p < 0.032) and post-operatively (p < 0.003). CONCLUSIONS: RTS placement is associated with MUL increase, elevation of the BN, BPW and EUS. De novo development of periurethral or urethral fibrosis seems not to be confirmed. The RTS failure was related to the severity of pre- and post-operative periurethral fibrosis. The impact of MRI on pre-operative diagnostics of RTS failure needs further evaluation.

X-treme CT analysis of cancellous bone at the rotator cuff insertion in human individuals with osteoporosis: superficial versus deep quality.

PURPOSE: Rotator cuff (RC) repair-especially in the elderly population-is problematic since the patients suffer to a high extent from bone mineral density loss at the reattachment site. Therefore, the study was primarily driven by the question whether it is possible to reach more or qualitatively better cancellous bone and thus a more stable postoperative result if anchors with greater length are used for RC repair and/or the conventional anchors are screwed deeper into the bone. In anatomical terms, the question is raised whether cancellous bone is of better quality close to or far off the RC enthesis. METHODS: Axial HRqCT scans (X-tremeCT, Scanco Medical) of 36 human cadaveric humeral heads (75 ± 11 years) were performed to determine the ratio of bone volume to total volume (BV/TV), trabecular thickness (Trab Th), number of trabecles (Trab N), trabecular separation (Trab Sp) as well as non-metric indices such as connectivity density (Conn Dens) and structure model index (SMI). Within the greater tuberosity (GT), 6 volumes of interest (VOI) (A1, B1, C1, A2, B2, C2), in the lesser tuberosity (LT) 2 VOIs (D1, D2) and one control VOI in the subchondral bone were set. The analyzed bone cylinder of each VOI was divided into a superficial and a deep portion. RESULTS: The parameters BV/TV, Trab N, Trab Th and Conn Dens in all volumes of the GT and LT revealed higher values in the superficial portion reaching different levels of significance (p < 0.001/<0.05). The only parameter presenting a higher value in the deep portion was Trab Sp, but this was the case for all GT and LT regions. Interestingly, the difference between the superficial and deep portion reached significance for the non-metric parameter SMI in no volume of the GT/LT, although the higher values were found superficially. CONCLUSIONS: Our data show that cancellous bone presents with decreasing bone quality when analyzing increasingly deeper portions of the bone cylinders of the GT and LT starting at the articular surface. This information seems to be crucial for shoulder surgeons, especially when treating elderly patients. Our results clearly prove that screwing in anchors to a deeper extent will not improve stability, since the deeper bone stock is of worse quality.

Age and gender as determinants of the bone quality of the greater tuberosity: a HR-pQCT cadaver study.

BACKGROUND: Age-dependent trabecular changes of the humeral head might weaken the fixation of suture anchors used for rotator cuff (RC) repair. This might lead to suture anchor loosening and thus compromise the integrity of the repair. The aim of this study was to analyze whether the trabecular microstructure within the RC footprint is influenced by age, gender or handedness. METHODS: Axial HR-pQCT scans (Scanco Medical) of 64 freshly frozen cadaveric human humeral head specimens (age 72.3 ± 17.4 years) were analyzed to determine the bone volume-to-total volume ratio (BV/TV), trabecular thickness (Trab Th), trabecular number (Trab N) and connectivity density (Conn Dens). Within the RC footprint, 2 volumes of interest (VOI), posteromedial (PM) and anterolateral (AL) and one control VOI in the subarticular bone (SC) were set. RESULTS: The highest BV/TV was found in SC: 0.22 ± 0.06% vs. PM: 0.04 ± 0.05% vs. AL: 0.02 ± 0.04%; p < 0.05. Trab Th accounted for 0.26 ± 0.05 µm in SC, 0.23 ± 0.09 µm in AL and 0.21 ± 0.05 µm in PM. In parallel, Trab N and Conn Dens were found to be the highest in SC. Gender analysis yielded higher values for BV/TV, Trab Th, Trab N and Conn Dens for PM in males compared to females (p < 0.05). There were no significant findings when comparing both sides. We furthermore found a strong inverse correlation between age and BV/TV, which was more pronounced in the female specimens (r = -0.72, p < 0.00001). CONCLUSIONS: The presented microarchitectural data allow for future subtle biomechanical testing comprising knowledge on age- and sex-related changes of the tuberosities of the humeral head. Furthermore, the insights on the trabecular structure of the humeral head of the elderly may lead to the development of new fixation materials in bone with inferior bone quality.

Assessment of colon motility using simultaneous manometric and functional cine-MRI analysis: preliminary results.

PURPOSE: Gastrointestinal functional disorders are common symptoms. The evaluation of underlying colonic motility dysfunction is difficult due to lacking adequate examination techniques. Recently cine-magnetic resonance imaging (MRI) was introduced as imaging technique for visualizing colon motility. However, the correlation of MR-visible colonic-movements and real intraluminal movements was not demonstrated yet. Therefore, this feasibility study's purpose was to stimulate high amplitude propagated pressure waves (HAPPWs) by bisacodyl application under manometric control and to simultaneously identify them with cine-MRI. MATERIALS AND METHODS: Colonoscopically, a water-perfused 8-lumen-probe was placed in descending colon. Intraluminal pressure was recorded over time. After 90 min equilibration phase, MR exam at rest (HASTE-sequence, 1.5Tesla-Avanto(®), Siemens-Medical-Solutions) was performed. Consecutively, 10 mg bisacodyl were instilled via colonic probe to induce HAPPWs. Cine-MRI and manometry were performed simultaneously over 24 min. HAPPWs were defined as pressure waves with amplitude >50 mmHg and propagation over min. three side-holes. MRI was analyzed for corresponding luminal changes of the referring colonic segment propagated aborally. RESULTS: Ten healthy volunteers (age:19-62 years, 4 females, 6 males) were enrolled. Manometry identified 11 HAPPWs, most 9-16 min post-stimulation. All HAPPWs were identified on MRI with corresponding luminal changes (100% sensitivity). CONCLUSIONS: In accordance with our study group's previous publications, these results show that cine-MRI allows not only for reliable HAPPWs' visualization using pharmalogical stimuli, but visualized colonic movements have 100% correlation to intraluminal pressure changes in manometry (gold-standard). This may be a first step to introduce cine-MRI for non-invasive colon motility assessment in patients with functional gastro-intestinal disorders.

Cyanoacrylate glue for intra-abdominal mesh fixation of polypropylene-polyvinylidene fluoride meshes in a rabbit model.

BACKGROUND: Cyanoacrylate glues are tissue adhesive with high adherent and hemostatic properties. The aim of this study was to evaluate the efficacy of cyanoacrylates glue for polypropylene-polyvinylidene fluoride (PP-PVDF) intraperitoneal onlay mesh (IPOM) fixation in a rabbit model. MATERIALS AND METHODS: In 40 New Zealand white rabbits, three pieces (3×3cm) of a PP-PVDF mesh (n=120) were fixed in IPOM technique on both sides of a midline laparotomy. For mesh fixation we used spiral tacks, nonabsorbable sutures, or cyanoacrylate glue in a randomized manner. All animals were killed after 12 wk. The prosthetic materials were excised en bloc with the anterior abdominal wall for evaluation of the tensile strength and histologic analysis. Results are presented as mean and standard deviation. RESULTS: Meshes fixed with glue showed a significantly higher tenacity of adhesions (2.75±0.97) compared with those with tacks (2.44±0.97 sutures versus 1.91±0.92 tacks). The percentage of adhesions in the glue group was comparable to the suture group (36.50% ± 27.60% glue, 37.62% ± 27.36% suture). The tensile strength of stapled and sutured meshes was significantly higher than the tensile strength glued mesh (14.15±0.97N suture versus 14.84±0.74 stapler versus 9.64±0.78N glue). Mesh shrinkage was irrespective of the fixation technique. The inflammation reaction was more pronounced in the glue group. CONCLUSIONS: Although cyanoacrylate glue showed a considerable cellular ingrowth in this rabbit model, sutures and tacks proved to be superior for IPOM fixation of PP-PVDF meshes in terms of tensile strength.

A novel tool for objective assessment of femorotibial rotation: a cadaver study.

Traumatic rupture of the anterior cruciate ligament (ACL) of the knee is one of the most frequent orthopaedic sports' injuries. However, the best operative reconstruction technique is still the focus of current discussions among experts. While single-bundle reconstruction primarily addresses anterior-posterior instability, the anatomical double-bundle reconstruction aims to stabilise anterior-posterior as well as rotational instability. So far no definite evidence to favour the one or the other technique exists due to the lack of an objective method for quantifying rotational knee stability. In this context several authors have recently reported on devices for the analysis of femorotibial rotation. However, most of these tools are still in the developmental stage. Therefore, the aim of this study was (1) to develop a new instrument for assessing rotational knee stability independent from the surrounding soft tissue with an adequate method of analysis and (2) to establish the possible field of application of this device in a human cadaver study. The so-called torsiometer evaluated was designed to assess internal and external knee joint rotation objectively in different flexion angles. Measurements were performed implying internal and external rotation at 90°, 30° and 0° knee flexion with and without intact ACL, respectively. Each measurement revealed valid and reproducible values. The restraint in ACL-absent knees was clearly lower and the course of rotation explicitly higher than in knee joints with intact ACL.