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Purpose The study sought to investigate the reliability of CT-derived Hounsfield unit (HU) measurements and ascertain the correlation between HU with qCT-derived bone mineral density (BMD) in cases of traumatic thoracolumbar fracture, based on native CT scans. Methods This study is a retrospective cross-sectional analysis of data sets from patients, which received native CT scans and bone mineral density measurements (qCT) of the same vertebral body. Two different CT scanner models were used. The inter-rater reliability of four rater, which measured HU in native CT scans, was calculated using intra class correlation coefficient for absolute agreement (ICC(3, 1)). For the correlation between HU and qCT values, respectively the prediction of qCT based on HU, linear regression was used. Bland-Altman plots were used for visual comparison of predicted and measured qCT values. Results In total 305 datasets were analyzed. CT scanner model were found to have no significant impact on HU (p=0.125). The inter-rater reliability for HU measurements from native CT scans was ICC(3, 1)=0.932 (CI95: 0.919 – 0.943, p Conclusions HU measurement shows very high inter-rater reliability. The HU values correlate closely with qCT BMD values. In summary, it seems that HU measurement is a suitable tool to readily and accurately assess bone quality without further scans or effort in cases of thoracolumbar spinal trauma.

Treatment of pertrochanteric femoral fractures is often associated with significant blood loss. It has already been demonstrated that the administration of tranexamic acid (TXA) for endoprosthetic procedures reduces blood losses and leads to a decreased frequency of postoperative complications. The aim of this study is to demonstrate whether the administration of TXA as part of osteosynthesis treatment for pertrochanteric fractures using a proximal femoral nail reduces perioperative blood losses and haemorrhage-related complications.In a two-centre retrospective cohort study, 1 g TXA i.v. was administered preoperatively to 294 patients who had suffered from pertrochanteric femoral fractures. The subjects were compared clinically to a historical control group who did not receive TXA (nonTXA). Outcomes were evaluated on the basis of perioperative blood loss, transfusion requirement, and occurrence of complications.The TXA group showed evidence of a reduction in blood loss (TXA = 0.97 ± 0.47 l; nonTXA = 1.06 ± 0.47 l; p = 0.004) and a lower frequency of transfusion (TXA = 20%; nonTXA = 31%; p = 0.032) as compared to the nonTXA group. However, evidence of this therapeutic effect could only be demonstrated at one of the centres on subgroup comparison between the two centres. At the second centre, the data did not show a significant difference. A trend could be seen towards a reduction in postoperative renal failure. No complications occurred resulting from the administration of tranexamic acid.Preoperative administration of TXA does not lead to an increased rate of thromboembolic complications when applied for treatment of pertrochanteric femoral fractures. Evidence of a positive effect could be seen in principle in relation to the reduction in perioperative blood loss and the frequency of transfusion. The difference in effect between the two centres remains to be clarified: for this reason, it is possible to assume that further factors influencing the efficacy of TXA administration are at play which were not taken into account in this study.

Objectives Osteoporotic fractures of the pelvis (OFP) are an increasing issue in orthopedics. Current classification systems (CS) are mostly CT-based and complex and offer only moderate to substantial inter-rater reliability (interRR) and intra-rater reliability (intraRR). MRI is thus gaining importance as a complement. This study aimed to develop a simple and reliable CT- and MRI-based CS for OFP. Methods A structured iterative procedure was conducted to reach a consensus among German-speaking spinal and pelvic trauma experts over 5 years. As a result, the proposed OF-Pelvis CS was developed. To assess its reliability, 28 experienced trauma and orthopedic surgeons categorized 25 anonymized cases using X-ray, CT, and MRI scans twice via online surveys. A period of 4 weeks separated the completion of the first from the second survey, and the cases were presented in an altered order. While 13 of the raters were also involved in developing the CS (developing raters (DR)), 15 user raters (UR) were not deeply involved in the development process. To assess the interRR of the OF-Pelvis categories, Fleiss’ kappa (κF) was calculated for each survey. The intraRR for both surveys was calculated for each rater using Kendall’s tau (τK). The presence of a modifier was calculated with κF for interRR and Cohen’s kappa (κC) for intraRR. Results The OF-Pelvis consists of five subgroups and three modifiers. Instability increases from subgroups 1 (OF1) to 5 (OF5) and by a given modifier. The three modifiers can be assigned alone or in combination. In both surveys, the interRR for subgroups was substantial: κF = 0.764 (Survey 1) and κF = 0.790 (Survey 2). The interRR of the DR and UR was nearly on par (κF Survey 1/Survey 2: DR 0.776/0.813; UR 0.748/0.766). The agreement for each of the five subgroups was also strong (κF min.–max. Survey 1/Survey 2: 0.708–0.827/0.747–0.852). The existence of at least one modifier was rated with substantial agreement (κF Survey 1/Survey 2: 0.646/0.629). The intraRR for subgroups showed almost perfect agreement (τK = 0.894, DR: τK = 0.901, UR: τK = 0.889). The modifier had an intraRR of κC = 0.684 (DR: κC = 0.723, UR: κC = 0.651), which is also considered substantial. Conclusion The OF-Pelvis is a reliable tool to categorize OFP with substantial interRR and almost perfect intraRR. The similar reliabilities between experienced DRs and URs demonstrate that the training status of the user is not important. However, it may be a reliable basis for an indication of the treatment score.

The goal of surgery for spinal injuries is fracture reduction, fixation and stable healing in a physiological position. Several open and minimally invasive surgical techniques are available.The extent of open reduction and the fixation potential achieved by the AOSpine (AT) and Kluger (KT) techniques were compared. The influence of fracture morphology, age, sex, and bone quality on fracture reduction and secure fixation was investigated.In this monocentric retrospective cohort study data of patients with traumatic thoracolumbar and lumbar fractures treated by AT or KT were analyzed. The bisegmental kyphotic angle (bGDW) of each injured spinal segment was determined. Normal bGDW values were extrapolated from the literature. The change of bGDW over time was analyzed under consideration of the bone quality in Hounsfield units (HU), injury severity according to the AOSpine classification, gender and age of patients.A total of 151 data sets were evaluated. The AT and KT methods achieved a similar extent of reduction (AT 10 ± 6°, KT 11 ± 8°; p = 0.786). In follow-up a mean reduction loss of -5 ± 4° was seen. The technique had no influence on this (p = 0.998). The fracture morphology just managed to achieve a significant influence (p = 0.043). Low HU correlated significantly but weakly with lower extent of reduction (r = 0.241, p 0.003) and greater reduction loss (r = 0.272, p 0.001). In the age group 50-65 years 21% of men and 43% of women had bone quality of 110 HU. Age and HU were significantly correlated (r = -0.701, p 0.001).The AT and KT are equivalent in terms of reduction and secure fixation properties. The high proportion of male and female patients with HU 110 in the age group under 65 years and the influence on reduction and secure fixation emphasize the need for preoperative bone densitometry.HINTERGRUND: Ziel der Operation von Wirbelsäulenverletzungen ist eine stabile Ausheilung in physiologischer Stellung. Für offene und perkutane Operationen stehen unterschiedliche Techniken zur Verfügung.Das Ausmaß der offenen Reposition und das Retentionspotenzial der Techniken nach AOSpine (AT) und nach Kluger (KT) sollen verglichen werden. Der Einfluss von Frakturmorphologie, Alter, Geschlecht und Knochenqualität auf Reposition und Retention werden untersucht.In dieser monozentrischen retrospektiven Kohortenstudie wurden Daten von Patienten mit traumatischen thorakolumbalen und lumbalen Frakturen untersucht, welche entweder mit AT oder KT reponiert wurden. Mittels bisegmentalen Grund-Deckplatten-Winkels (bGDW) wurde die Stellung des verletzten Wirbelsäulenabschnitts beschrieben. Normalwerte für die bGDW wurden anhand von Literaturdaten angenommen. Die Veränderung des bGDW im zeitlichen Verlauf wurde unter Einbeziehung der Knochenqualität in Hounsfield Units (HU), der Verletzungsschwere nach AOSpine und des Patientenalters und -geschlechts analysiert.Es wurden 151 Datensätze ausgewertet. Beide Methoden reponieren vom Umfang nicht unterschiedlich (AT 10 ± 6°, KT 11 ± 8°; p = 0,786). Im Follow-up trat ein Korrekturverlust von −5 ± 4° auf. Die Technik (p = 0,998) hatte keinen Einfluss darauf. Die Frakturmorphologie zeigte einen knapp signifikanten Einfluss (p = 0,043). Niedrige HU korrelierten mit geringerem Repositionsumfang (r = 0,241, p 0,003) und größerem Korrekturverlust (r = 0,272, p 0,001) signifikant, aber schwach. In der Altersgruppe 50 bis 65 Jahre wiesen 21 % der Männer und 43 % der Frauen eine Knochenqualität von HU 110 auf. Alter und HU korrelieren signifikant (r = −0,701, p 0,001).Die Techniken sind gleichwertig bezüglich der Repositions- und Retentionseigenschaften. Der hohe Anteil von Patienten mit HU 110 in der Gruppe unter 65 Jahren bei Frauen und Männern und der Einfluss auf Reposition und Retention weisen auf die Notwendigkeit einer präoperativen Knochendichtemessung hin.

Purpose Posterior multilevel fixation of traumatic instability in ankylosing spinal disease (ASD) can be performed by open surgery (OS) or minimally invasive surgery (MIS). We investigated whether both methods differ based on the reduction results and perioperative parameters. Methods In this retrospective cohort study, OS and MIS groups were investigated. The bisegmental Cobb angles and dislocation angles were measured using pre- and postoperative CT images, and the initial malalignment and achieved reduction were calculated. Cut-seam time, calculated blood loss, transfusion number, fluoroscopy time, pedicle screw placement accuracy, duration of ICU stay, in-patient stay, and complications (bleeding, postoperative thrombosis and embolism, and postoperative mortality) were recorded. Results Seventy-five ASD patients with spine fractures (Ø 75 ± 11 years, male: 52, female: 23) (MIS: 48; OS: 27) were included in this study. The extent of reduction did not differ in the OS and MIS groups (p = 0.465; MIS:− 1 ± 3°, OS:−2 ± 6°). The residual postoperative malalignment angle was not significantly different (p = 0.283). Seventy-eight of the implanted screws (11%) showed malpositioning. No difference was found between OS and MIS (MIS, 37 [7%]; OS, 41 [16%]; p = 0.095). MIS was associated with less blood loss (OS: 1.28 ± 0.78 l, MIS: 0.71 ± 0.57 l, p = 0.001), cut-seam time (MIS: 98 ± 44 min, OS: 166 ± 69 min, p p = 0.02) than OS. Conclusion OS and MIS show equally limited performance in terms of the fracture reduction achieved. The MIS technique was superior to OS based on the perioperative outcome. Therefore, MIS should be preferred over OS for unstable spinal injuries, excluding C-type fractures, in ASD patients without neurological impairment.

Minimally invasive fixation of pelvic fragility fractures is recommended to reduce pain and allow early mobilization. The purpose of this study was to evaluate the outcome of two different stabilization techniques in bilateral fragility fractures of the sacrum (BFFS).A non-randomized, prospective study was carried out in a level 1 trauma centre. BFFS in 61 patients (mean age 80 years (SD 10); four male, 57 female) were treated surgically with bisegmental transsacral stablization (BTS; n = 41) versus spinopelvic fixation (SP; n = 20). Postoperative full weightbearing was allowed. The outcome was evaluated at two timepoints: discharge from inpatient treatment (TP1; Fitbit tracking, Zebris stance analysis), and ≥ six months (TP2; Fitbit tracking, Zebris analysis, based on modified Oswestry Disability Index (ODI), Majeed Score (MS), and the 12-Item Short Form Survey 12 (SF-12). Fracture healing was assessed by CT. The primary outcome parameter of functional recovery was the per-day step count; the secondary parameter was the subjective outcome assessed by questionnaires.Overall, no baseline differences were observed between the BTS and SP cohorts. In total, 58 (BTS = 19; SP = 39) and 37 patients (BTS = 14; SP = 23) could be recruited at TP1 and TP2, respectively. Mean steps per day at TP1 were median 308 (248 to 434) in the BTS group and 254 (196 to 446) in the SP group. At TP2, median steps per day were 3,759 (2,551 to 3,926) in the BTS group and 3,191 (2,872 to 3,679) in the SP group, each with no significant difference. A significant improvement was observed in each group (p0.001) between timepoints. BTS patients obtained better results than SP patients in ODI (p0.030), MS (p = 0.007), and SF-12 physical status (p = 0.006). In all cases, CT showed sufficient fracture healing of the posterior ring.Both groups showed significant outcome improvement and sufficient fracture healing. Both techniques can be recommended for BFFS, although BTS was superior with respect to subjective outcome. Step-count tracking represents a reliable method to evaluate the mobility level. Cite this article

A retrospective, longitudinal cohort study.The purpose of this study was to examine whether Hounsfield units (HUs), as an alternative bone mineral density measurement to dual-energy X-ray absorptiometry and quantitative computed tomography, which lead to additional radiation exposure for patients, has an effect on the maintenance of reduction in bisegmental Cobb angle (CA) and cage subsidence in patients who receive bisegmental spine stabilization after traumatic thoracolumbar spine fractures.A total of 81 patients with a mean follow-up of 12 months were analyzed. CAs and cage subsidence were measured intraoperatively and at follow-up. HU was measured, and patients were subsequently assigned based on HU to three HU subgroups (group 1: HU 110 [poor bone quality (BQ)]; group 2: HU 180-110 [diminished BQ]; group 3: HU 180 [good BQ]).Following anterior stabilization, loss of reduction and cage subsidence differed between patients with poor and diminished BQ but not significantly, and both groups showed significantly more loss of reduction and cage subsidence than patients with good BQ.BQ, estimated with HU, had significant effects on cage subsidence and loss of reduction. We recommend measuring HU before surgery and applying additional treatment strategies, such as polymethylmethacrylate augmentation of endplates or anterior plates, for patients with HU 180. These slides can be retrieved under Electronic Supplementary Material.

Background The Sorensen test is commonly used to assess back muscle endurance capacity. However, the clinical value of this test, requiring compensation of the entire upper body mass, is limited if pain occurs. Therefore, a test variant using only portions of upper body mass could be an alternative. Objective This study aimed to determine fatigue characteristics in lumbar muscles during a modified Sorensen test utilizing only 50% of the upper body mass and asked if localization-related effects of surface electrodes in the assessment of lumbar muscle fatigue should be considered. Methods Thirty-two young (20-29 years) symptom-free men were enrolled and asked to maintain only 50% upper body mass for 10 minutes. Fatigue characteristics were bilaterally derived from four different lumbar levels using Surface EMG. Side-specific and SEMG parameter-independent repeated measures (four lumbar levels, nine time points) analyses of variance were conducted. Results All participants were able to complete the test. Over time, a spatial effect of fatigue-related amplitude alterations at the respective segments could be observed. Conclusions By using this modified Sorensen test, muscular fatigue can be evoked. Electrophysiological assessment of lumbar fatigue should consider spatial differences.

OBJECTIVE The aim of the study was to analyze the microbial colonization rate as well as the spectrum and number of microorganisms in relation to the indwelling time of pancreatic stents. METHODS Forty pancreatic stents were prepared according to a standardized protocol and subsequently sonicated to optimize bacterial release from the biofilm on the stents. RESULTS Two hundred forty-six microorganisms were identified. Thirty-nine of 40 stents were colonized with microorganisms. Aerobic gram-positive microorganisms (106/246 [43%]) accounted for the greatest proportion. The predominant microorganisms were Streptococcus species (46/246 [19%]), which were isolated from 27 (68%) of 40 stents. Stents with a short indwelling time (3-13 days) were mainly colonized with aerobic gram-positive bacteria (82%) and Candida species (63%). In contrast, anaerobes (P < 0.01, 69% vs 18%) and aerobic gram-negative microorganisms (P < 0.01, 93% vs 45%) such as Enterobacteriaceae (P < 0.01, 86% vs 27%) were significantly more present on stents with a long indwelling time (29-93 days), compared with stents with a short indwelling time. CONCLUSIONS Microbial analysis of pancreatic duct stents revealed a very high colonization rate. Furthermore, the spectrum and number of microorganisms altered with the indwelling time of the stent. However, clinical relevance of our findings remains unclear.

Bacterial colonization of biliary stents is one of the driving forces behind sludge formation which may result in stent occlusion. Major focus of the study was to analyze the spectrum and number of microorganisms in relation to the indwelling time of stents and the risk factors for sludge formation. 343 stents were sonicated to optimize the bacterial release from the biofilm and identified by matrix-associated laser desorption/ionization-time of flight mass spectrometer (MALDI-TOF). 2283 bacteria were analyzed in total. The most prevalent microorganisms were Enterococcus species (spp.) (504;22%), followed by Klebsiella spp. (218;10%) and Candida spp. (188;8%). Colonization of the stents mainly began with aerobic gram-positive bacteria (43/49;88%) and Candida spp. (25/49;51%), whereas stents with an indwelling time>60 days(d) showed an almost equal colonization rate by aerobic gram-negative (176/184;96%) and aerobic gram-positive bacteria (183/184;99%) and a high proportion of anaerobes (127/184;69%). Compared to stents without sludge, more Clostridium spp. [(P = 0.02; Odds Ratio (OR): 2.4; 95% confidence interval (95%CI): (1.1-4.9)]) and Staphylococcus spp. [(P = 0.03; OR (95%CI): 4.3 (1.1-16.5)] were cultured from stents with sludge. Multivariate analysis revealed a significant relationship between the number of microorganisms [P

To judge a person’s maximum trunk extension performance as either age-appropriate or deconditioned is challenging. The current study aimed at determining age and anthropometrically adjusted maximum voluntary contraction (MVC) of back extensors considering the number and recovery time between trials. Thirty-one younger (20–30 years) and 33 older (50–60 years) healthy males performed five repetitions of maximal isometric trunk extensions in an upright standing position with randomized recovery times ranging between one to five minutes at one minute intervals. Torque values were normalized according to the individual’s upper body mass resulting in upper body torque ratios (UBTR). To evaluate the impact of age, recovery time, and fatigue on UBTR we applied a linear mixed-effects model. Based on surface EMG data muscular fatigue could be excluded for both groups. For all MVC trials, UBTR levels differed significantly between age groups (range of mean values: younger: 2.26–2.28, older: 1.78–1.87, effect size: 1.00) but were independent from recovery time. However, the older males tended to exert higher UBTR values after shorter recovery periods. The study provides normative values of anthropometrically and age-group adjusted maximum back extensor forces. For the investigated groups, only two MVC trials with a recovery time of about one minute seem appropriate.

Exact electrode positioning is vital for obtaining reliable results in Surface EMG. This study aimed at systematically assessing the influence of defined electrode shifts on measured Surface EMG amplitudes of trunk muscles in a group of 15 middle aged healthy male subjects. The following leftsided muscles were investigated: rectus abdominis muscle, internal and external oblique abdominal muscles, lumbar multifidus muscle, and longissimus muscle. In addition to the recommended electrode positions, extra electrodes were placed parallel to these and along muscle fiber direction. Measurements were performed under isometric conditions in upright body position. Gradually changing, but defined loads were applied considering subject's upper body weight. For the abdominal muscles amplitude differences varied considerably depending on load level, magnitude, and direction. For both back muscles amplitudes dropped consistently but rather little for parallel electrode displacements. However, for the longissimus muscle a caudal electrode shift resulted in an amplitude increase of similar extent and independent from load level. Influence of electrode position variations can be proven for all trunk muscles but are more evident in abdominal than back muscles. Those muscle-specific effects confirm the necessity for an exact definition of electrode positioning to allow comparisons between individual subjects, groups of subjects, and studies.