Relation between sagittal pelvic and thoracolumbar parameters in supine position - Pelvic parameters and their predictive value for spinal Cobb angles.

Introduction: Predicting the pre-morbid sagittal profile of the spine or segmental angles could enhance the process of planning the extent of fracture reduction. There is evidence that spinopelvic parameters may be suitable for this purpose. Research question: Is it possible to determine the inflection point and the mono- and bi-segmental endplate angles (EPA) in the thoracolumbar transition (from Th9 to L2) based on age, gender, spinopelvic parameters, and the adjacent EPA in the supine position? Material and methods: Based on Polytrauma CT scans in the supine position, the following spinopelvic parameters were measured using non-fractured spines: pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), and the apex of the LL. Results: In this study, a total of 287 patients with a mean age of 42±16 years were included. Age-related changes were observed, where LL, thoracic kyphosis (TK), and PI increase with age. Gender-related comparisons showed that females had a more pronounced LL and reduced TK. Significant correlations between IP and spinopelvic parameters, with the apex of LL providing the best prediction, were found. However, the overall model quality remained low. Predicting mEPA and bEPA showed positive correlations. The prediction for mEPA L2/3 demonstrated the highest correlation. For bisegmental angles, the most caudal bEPA (L2) exhibited the highest correlation, albeit with some notable absolute differences in the values between measured and predicted values. Discussion and conclusion: While this study highlights the complexity of the relationship between the pelvis and thoracolumbar parameters, finding a predictive tool for thoracolumbar reduction and stabilization was not possible.

Percutaneous reduction of thoracolumbar fractures using monoaxial screws: Comparison of two instruments based on initial reduction and loss of reduction.

Introduction: Percutaneous techniques for the surgical treatment of vertebral fractures are constantly progressing. There are different biomechanics involved. Research question: Two percutaneous, monoaxial fixation systems with different reduction tools were analyzed in relation to their reduction capacity. Additionally, the impact of anterior fusion, fracture severity and bone quality on reduction and loss of reduction were examined. Material and methods: 117 cases were retrospectively included in the monocentric study. The subsample (N = 53) with complete data at follow-up times was used to analyze the influence of anterior fusion. The dependencies on fracture severity and bone quality were determined using Spearman and Pearson correlation. Results: Both systems achieved equally good reduction (9° mean, 95%-CI: 8°-11°, p < 0.001). Anterior fused patients showed not significant (p = 0.057) less loss of reduction over time. Fracture severity had neither an influence on reduction or loss of reduction. Bone quality was positively correlated with greater amount of reduction and less loss of reduction. Early reduction within two days correlated with a greater amount of reduction (p = 0.006). Screw diameters and the patient's weight had no influence on loss of reduction. Complications occurred only in "V2" group. Discussion and conclusion: Both systems are equivalent in reduction ability. The additional anterior fusion did not result in significantly lower reduction losses. The subsample being small, is a limitation. Good bone quality correlates with better initial reduction and less reduction loss. A preoperative bone density measurement can lead to optimization of surgical techniques.

Comparison of the zonal distribution of calcium salt density and fat marrow in bone-healthy and osteoporotic sacra: an image data analysis using quantitative computed tomography and magnetic resonance imaging.

PURPOSE: Pathogenesis of sacral fragility fractures is not fully understood. This study investigates zonal distribution of calcium salt and fat marrow in intact bone-healthy and osteoporotic pelvis. In addition, in unilateral sacral fractures, the fracture side was compared with the intact side. METHODS: CT and MRI images of 37 pelves were analyzed. Zonal calcium salt distribution by Hounsfield units (HU) was recorded for each CT dataset. Fat marrow content was measured in MRI mDixon-Quant sequence. The cohort was divided: intact pelves with (PEO, HU < 100, n = 8) and without osteoporosis (PE, HU ≥ 100, n = 14) based on the mean HU value in LWK5. A third group consisted of patients with osteoporosis and unilateral fractures (PEOFx, n = 10). CONCLUSION: The results suggest that in PEO sacral alae experience disproportionate skeletal rarefaction. This concerns the sacral ala at the S1 level (- 25 ± 55), whereby the calcium salt content is so low that it corresponds to the S3 level of healthy bone (- 20 ± 21 HU). This explains the occurrence of transalar fractures in the load-transmitting zone S1. In PEOFx, the calcium salt density was higher and the fat content was lower on the fractured side than on the intact side, indicating bony compacting due to lateral compression and fat displacement due to hematoma in the accident mechanism. This study makes an important contribution to the understanding of the development of sacral fragility fractures. Furthermore, impaction of the cancellous bone within the fracture can be demonstrated.

The Halofixator for the Treatment of Unstable Fractures of the Upper Cervical Spine - Our Own Experience and Narrative Review. / Der Halofixateur zur Therapie von instabilen Frakturen der oberen Halswirbelsäule ­ eigene Erfahrungen und narratives Review.

INTRODUCTION: In the treatment of upper cervical spine injuries, the semiconservative procedure of the halofixator is now of only secondary importance. Older studies from the 2000 s showed unsatisfactory rates of consolidation as well as high rates of complications. However, due to current data on therapy effectiveness, the literature is inconsistent. The aim of this work is to compare our own experiences and results of treatment with the current literature and to help to clarify the role of the halofixator. MATERIAL AND METHODS: In a monocentric retrospective cohort study, patients with unstable injuries of the axial cervical spine who were to be treated in the halofixator were investigated. Individual variables (sex, age, concomitant diseases, Charlson Comorbidity Index) and treatment characteristics (duration of treatment, consolidation status, complications) were recorded using the electronic medical record. Injuries were classified based on CT data at the time of the accident and at the end of treatment, using common classification systems, and assessed with respect to the rate of consolidation. Possible factors influencing bony consolidation as well as complications were statistically analysed. RESULTS: A total of 54 patients met the inclusion criteria. The median duration of treatment was 83 days. The most common injuries were isolated atlas fracture type III (7; 13%) and isolated dens fracture type III (24; 44%). Bony consolidation was demonstrated in 34 cases (63%) and tight pseudarthrosis in 13 cases (24%). Secondary surgical stabilisation was performed in 6 cases (11%). Isolated type III atlas fractures and type III dens fractures had very high consolidation rates of 86% and 92%, respectively. In the subgroups of patients older than 65 years or with a CCI ≥ 4, unstable pseudarthroses were found more frequently. Complications included pin infection (6%), pin dislocation (9%), and pressure ulceration from the halo vest (6%). Cardiopulmonary complications did not occur. No patient died. DISCUSSION: Good rates of bony consolidation were seen for atlas fractures type III as well as dens fractures type III, which correlate with data in the literature. Dens fractures type II (isolated and combined) and atlas fractures type III in combination with dens fractures showed a worse radiological outcome, which is also unsatisfactory compared to the literature. The rates for procedure-specific complications were relatively low. In particular, work from recent years has demonstrated very good rates for bony consolidation and low complication rates for the treatment of atlas and/or dens fractures with the halofixator, which are confirmed by our results. In contrast, however, a significantly higher cardiac/respiratory complication rate has been reported than occurred in our own patient population.

Georg Schmorl prize of the German spine society (DWG) 2022: current treatment for inpatients with osteoporotic thoracolumbar fractures-results of the EOFTT study.

AIM: Osteoporotic thoracolumbar fractures are of increasing importance. To identify the optimal treatment strategy this multicentre prospective cohort study was performed. PURPOSE: Patients suffering from osteoporotic thoracolumbar fractures were included. Excluded were tumour diseases, infections and limb fractures. Age, sex, trauma mechanism, OF classification, OF-score, treatment strategy, pain condition and mobilization were analysed. METHODS: A total of 518 patients' aged 75 ± 10 (41-97) years were included in 17 centre. A total of 174 patients were treated conservatively, and 344 were treated surgically, of whom 310 (90%) received minimally invasive treatment. An increase in the OF classification was associated with an increase in both the likelihood of surgery and the surgical invasiveness. RESULTS: Five (3%) complications occurred during conservative treatment, and 46 (13%) occurred in the surgically treated patients. 4 surgical site infections and 2 mechanical failures requested revision surgery. At discharge pain improved significantly from a visual analogue scale score of 7.7 (surgical) and 6.0 (conservative) to a score of 4 in both groups (p < 0.001). Over the course of treatment, mobility improved significantly (p = 0.001), with a significantly stronger (p = 0.007) improvement in the surgically treated patients. CONCLUSION: Fracture severity according to the OF classification is significantly correlated with higher surgery rates and higher invasiveness of surgery. The most commonly used surgical strategy was minimally invasive short-segmental hybrid stabilization followed by kyphoplasty/vertebroplasty. Despite the worse clinical conditions of the surgically treated patients both conservative and surgical treatment led to an improved pain situation and mobility during the inpatient stay to nearly the same level for both treatments.

Perioperative outcome of minimally invasive stabilisation of bilateral fragility fractures of the sacrum: a comparative study of bisegmental transsacral stabilisation versus spinopelvic fixation.

PURPOSE: Pelvic fragility fractures have steadily risen over the past decades. The primary treatment goal is the fastest possible mobilisation. If conservative therapy fails, surgical fixation is a promising approach. This study compares the outcome of bisegmental transsacral stabilisation (BTS) and spinopelvic fixation (SP) as minimally invasive techniques for bilateral fragility fractures of the sacrum (BFFS). METHODS: We performed a prospective, non-randomised, case-controlled study. Patients were included if they remained bedridden due to pain despite conservative treatment. Group assignment depended on sacral anatomy and fracture type. The outcome was estimated by blood loss calculation, cut-seam time, fluoroscopy time, complications, duration of stay at the intensive/intermediate care unit (ICU/IMC), and total inpatient stay. The mobility level at discharge was recorded. RESULTS: Seventy-three patients were included (SP: 49, BTS: 24). There was no difference in blood loss (BTS: 461 ± 628 mL, SP: 509 ± 354 mL). BTS showed a significantly lower cut-seam time (72 ± 23 min) than SP (94 ± 27 min). Fluoroscopy time did not differ (BTS: 111 ± 61 s vs. 103 ± 45 s). Thirteen percent of BTS and 16% of SP patients required ICU/IMC stay (BTS: 0.6 ± 1.8 days, SP: 0.5 ± 1.5 days) during inpatient stay (BTS: 9 ± 4 days, SP: 8 ± 3 days). Fourteen patients suffered from urinary tract infections (BTS: 8%; SP: 25%). In-patient mortality was low (BTS: 4.2%, SP: 4.1%). At discharge, the BTS group was almost back to the initial mobility level. In SP patients, mobility was significantly lower than before complaints (p = 0.004). CONCLUSION: Both methods allow early mobilization of BFFS patients. Blood loss can be kept low. Hence, transfusion requirement is correspondingly low. The IMC/ICU and the total inpatient stay are lower than reported in the literature. Both BTS and SP can be recommended as safe and low-complication methods for use in BFFS patients. BTS is superior to SP with respect to surgery duration and level of mobility at discharge.

Inter-Rater Reliability of Hounsfield Units as a Measure of Bone Density: Applications in the Treatment of Thoracolumbar Fractures.

OBJECTIVE: The study sought to investigate the reliability of computed tomography (CT)-derived Hounsfield unit (HU) measurements and ascertain the correlation between HU with quantitative CT (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 who 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 4 raters, which measured HU in native CT scans, was calculated using intraclass 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 data sets were analyzed. CT scanner model was 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 (95% confidence interval 0.919-0.943, P < 0.001). The linear regression showed significant correlation of HU and qCT values for each rater (P < 0.001). The equation for qCT prediction with averaged coefficient and constant is qCT = 0.8 HU + 5. In the Bland-Altman plots no bias of predicted qCT values could be found, but a trend to overestimate predicted higher qCT values and underestimate lower qCT values, respectively. 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.

OF-Pelvis classification of osteoporotic sacral and pelvic ring fractures.

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.

Mid-term outcome of bilateral fragility fractures of the sacrum after bisegmental transsacral stabilization versus spinopelvic fixation.

AIMS: 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). METHODS: 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. RESULTS: 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 (p < 0.001) between timepoints. BTS patients obtained better results than SP patients in ODI (p < 0.030), MS (p = 0.007), and SF-12 physical status (p = 0.006). In all cases, CT showed sufficient fracture healing of the posterior ring. CONCLUSION: 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: Bone Joint J 2021;103-B(3):462-468.

Progressive instability of bilateral sacral fragility fractures in osteoporotic bone: a retrospective analysis of X-ray, CT, and MRI datasets from 78 cases.

PURPOSE: The pathogenetic mechanism, progression, and instability in geriatric bilateral fragility fractures of the sacrum (BFFSs) remain poorly understood. This study investigated the hypothesis of sequential BFFS progression by analysing X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) datasets. METHODS: Imaging data from 78 cases were retrospectively analysed. Fractures were categorized using the CT-based Fragility Fractures of the Pelvis classification. MRI datasets were analysed to detect relevant fracture location information. The longitudinal sacral fracture was graded as stage 1 (bone oedema) on MRI, stage 2 (recent fracture), stage 3 (healing fracture), or stage 4 (non-union) on CT. Ligamentous avulsions at the L5 transverse process and iliac crest were also captured. RESULTS: Contralateral sacral lesions were only recognized by initial bone oedema on MRI in 17/78 (22%) cases. There were 22 cases without and 56 cases with an interconnecting transverse fracture component (TFC) [between S1/S2 (n = 39) or between S2/S3 (n = 17)]. With 30/78 patients showing bilateral fracture lines at different stages (1/2: n = 13, 2/3: n = 13, 1/3: n = 4) and 38 at similar stages, Wilcoxon tests showed a significant stage difference (p < 0.001). Forty cases had a coexistent L5 transverse process avulsion, consistent with a failing iliolumbar ligament. Analysis of variance revealed significant increases in ligamentous avulsions with higher fracture stages (p < 0.001). CONCLUSION: Our results support the hypothesis of stagewise BFFS progression starting with unilateral sacral disruption followed by a contralateral lesion. Loss of sacral alar support leads to a TFC. Subsequent bone disruption causes iliolumbar ligament avulsion. MRI is recommended to detect bone oedema.