Fractured Vertebra Research Articles

Comparison of correction of kyphotic deformity and implant failure in percutaneous short-segment pedicle screws fixation with index level versus long-segment pedicle screws fixation without index level for traumatic thoracolumbar junctional fractures

Objective: To compare correction of kyphotic deformity (KD) and implant failure (IF) in percutaneous short-segment pedicle screws fixation (SSPF) with index level versus long-segment pedicle screws fixation (LSPF) without index level for traumatic thoracolumbar (TL) fractures. Methods: This prospective study comprised 56 patients who met the study’s inclusion criteria from the Department of Neurosurgery at the Punjab Institute of Neurosciences in Lahore, Pakistan presented between June 2022 and May 2023. We separated them into two groups: Group-A and Group-B, each with 28 patients. Group-A consisted of percutaneous SSPF with incorporated screws in the fractured vertebra, whereas Group-B consisted of percutaneous LSPF without index level involvement for traumatic TL fractures. We reviewed the patient’s preoperative, postoperative, and follow-up radiographs. The quantitative factors such as Cobb’s angle and implant stability were investigated. Results: The study comprised individuals with a mean age of 31.5 ± 10.6 SD years. Out of 56 patients, 38 (67.85%) were male and 18 (32.14%) were female. The fracture level distribution was 37 (67.07%) patients with L1 fracture, 15 (26.78%) with D12 fracture, 2 (3.57%) with D11 fracture, and 2 (3.57%) with L2 fracture. Group-A had a preoperative Cobb’s angle of 18.8° ± 5.0° SD, whereas Group-B had 19.8° ± 6.3° SD (P-value=0.23). Immediate postoperative Cobb’s angle was 6.4° ± 3.4° SD in Group-A and 7.3° ± 3.7° SD in Group-B (P-value 0.66). After three months, Group-A had a Cobb’s angle of 7.1° ± 3.6° SD, whereas Group-B had 7.8° ± 3.7° SD (P-value = 0.78). Six-month follow-up Cobb’s angle was 7.9° ± 3.6° SD in Group-A and 8.4° ± 3.8° SD in Group-B (P-value=0.502). There were no implant failures in any group. Conclusions: For a single level traumatic TL fracture, SSPF with index level can preserve Cobb’s angle better than LSPF without index level, and it has high IF stability. List of Abbreviations:SSPF: Short-Segment Pedicle Screws Fixation, LSPF: Long-Segment Pedicle Screws Fixation, TL: Thoracolumbar, KD: Kyphotic Deformity, IF: Implant Failure, SD: Standard Deviation, SPSS: Statistical Package for Social Sciences, CT: Computed Tomography, MRI: Magnetic Resonance Imaging. doi: https://doi.org/10.12669/pjms.40.12(PINS).11110 How to cite this: Jehanzeb M, Khizar A, Shabbir MA, Shakir M, Anwar K, Bashir A. Comparison of correction of kyphotic deformity and implant failure in percutaneous short-segment pedicle screws fixation with index level versus long-segment pedicle screws fixation without index level for traumatic thoracolumbar junctional fractures: A prospective cohort study . Pak J Med Sci. 2024;40(12):S47-S54. doi: https://doi.org/10.12669/pjms.40.12(PINS).11110 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Poromechanical cohesive interface element with combined Mode I-II cohesive zone elastoplasticity for simulating fracture in fluid-saturated porous media

A combined Mode I-II cohesive zone (CZ) elasto-plastic constitutive model, and a two-dimensional (2D) cohesive interface element (CIE) are formulated and implemented at small strain within an ABAQUS User Element (UEL) for simulating 2D crack nucleation and propagation in fluid-saturated porous media. The CZ model mitigates problems of convergence for the global Newton-Raphson solver within ABAQUS, which when combined with a viscous stabilization procedure allows for simulation of post-peak response under load control for coupled poromechanical finite element analysis, such as concrete gravity dam stability analysis. Verification examples are presented, along with a more complex ambient limestone-concrete wedge fracture experiment, water-pressurized concrete wedge experiment, and concrete gravity dam stability analyses. A calibration procedure for estimating the CZ parameters is demonstrated with the limestone-concrete wedge fracture process. For the water-pressurized concrete wedge fracture experiment it is shown that the inherent time-dependence of the poromechanical CIE analysis provides a good match with experimental force versus displacement results at various crack mouth opening rates, yet misses the pore water pressure evolution ahead of the crack tip propagation. This is likely a result of the concrete being partially-saturated in the experiment, whereas the finite element analysis assumes fully water saturated concrete. For the concrete gravity dam analysis, it is shown that base crack opening and associated water uplift pressure leads to a reduced Factor of Safety, which is confirmed by separate analytical calculations.

Lumbar Spine Orientation Affects Compressive Fracture Outcome.

Understanding how spinal orientation affects injury outcome is essential to understand lumbar injury biomechanics associated with high-rate vertical loading. Whole-column human lumbar spines (T12-L5) were dynamically loaded using a drop tower to simulate peak axial forces associated with high-speed aircraft ejections and helicopter crashes. Spines were allowed to maintain natural lordotic curvature for loading, resulting in a range of orientations. Pre-test X-rays were used to quantify specimen orientation at the time of loading. Primary fracture types were identified (wedge, n = 6; burst, n = 4; hyperextension, n = 4) and compared for loading parameters and lumbar orientation. Fracture type was dependent on peak acceleration, bending moment, Cobb angle, sagittal spinal tilt, and location of the applied load. Lumbar spine orientation under high-rate axial acceleration affected the resulting fracture type. Analysis of pre-test X-rays revealed that spines that sustained wedge and burst fractures were oriented straighter at the time of loading. The load was applied centrally to T12 in spines with burst fractures, and anteriorly to T12 in spines with wedge fractures. Spines that sustained hyperextension fracture had lower peak accelerations, larger Cobb angles at the time of loading, and sustained larger extension moments. Fracture presentation is an important and understudied factor that influences biomechanical stability, clinical course, and long-term patient outcomes.

Feasibility study in quantitative identification of fresh and old osteoporotic vertebral compression fracture by vertebral CT value and CT value difference

BackgroundThis study aims to assess the diagnostic utility of vertebral CT value and CT value difference in distinguishing between fresh and old osteoporotic vertebral compression fractures (OVCF).MethodsA retrospective analysis was conducted on 118 patients with OVCF who underwent both MRI and CT examinations at our hospital. The nature of the fractured vertebra was determined according to MRI. The CT value of the fractured vertebrae and the mean CT value of the adjacent normal vertebrae were measured separately, and the differences between these values were calculated. Independent samples t-tests were used to compare CT value and CT value difference among all groups. The receiver operating characteristic (ROC) curve was employed to determine the optimal cut-off value for both CT value and CT value difference in differentiating fresh and old fractures.ResultsThe study included a total of 163 fractured vertebrae from 118 patients. The CT value of fresh fractured vertebrae was significantly higher than those of adjacent normal vertebrae, which was statistically different (P < 0.001). In contrast, the difference between CT value of old fractured vertebrae and those of adjacent normal vertebrae was not statistically significant (P > 0.05). There were significant differences in CT value and CT value difference between fresh fractured vertebrae and old fractured vertebrae (P < 0.001). The ROC curve analysis showed that the optimal cut-off value of CT value for fresh fractures and old fractures was 103.40 HU. The optimal cut-off value of CT value difference was 39.81 HU.ConclusionVertebral CT value and CT value difference offer a certain reference value for distinguishing between fresh and old OVCF. These parameters can serve as a rapid diagnostic tool when MRI is unavailable or impractical, aiding in the timely assessment of OVCF.

Outcome of posterior short segment fixation with implanting pedicle screw at the fractured level for treatment of thoracolumbar fracture

IntroductionThoracolumbar fractures make up majority of the spinal fractures. Various techniques including long, short, mono and short segment screw fixation have been used to achieve stability. There are still few studies describing the results of short segment fixation with intermediate screw fixation in fractured vertebrae, despite the fact that all have adequate efficacy and stability. Materials and methods41 patients were studied and evaluated preoperatively, at discharge and at 2, 6, 12, 24 weeks and 1 year follow-up clinically using Greenough and Fraser Low Back Pain Score, the American Spinal Injury Association (ASIA) grading, four-point scale questionnaire for patient's satisfaction, sagittal index (SI) of injured vertebra and Cobb's angle. ResultsThe patient's mean age was 36.9 ± 11.7 years, majority (90.2 %) with lumbar (L1-L3) segment involvement. All the patients significantly improved neurologically immediately after surgery (p < 0.001) however the improvement was not significant at final follow up (p = 0.3) as compared to the preoperative ASIA grade (Kendall's tau-b test). Low back pain decreased significantly on subsequent follow-up as measured by Visual Analogue Scale (VAS) score (p < 0.001). The Low Back Pain Scale of Greenough and Fraser calculated at immediate post-operation and at 1 year follow up in comparison to pre-operation status showed a statistically significant improvement (p < 0.001). Sagittal index (SI) estimated at 6, 12, 24 weeks and 1 year follow-up in comparison to preoperative SI was higher and statistically significant (p < 0.001). Mean Cobb's angle significantly decreased during follow-up at 6, 12, 24 weeks and 1 year compared to preoperative angle (p < 0.001). Four Point Scale Questionnaire assessed at 1 year follow-up showed majority (82.9 %) were very satisfied with the outcome. ConclusionPosterior short segment with intermediate screw fixation in fractured vertebra is a feasible and stable treatment method for traumatic single thoracolumbar fracture with respect to the functional outcome, patient satisfaction and preservation of motion segment.

Surgical management of thoracolumbar burst fractures by three different posterior techniques: A prospective comparative study

Study designProspective Comparative Study. ObjectivesThis study aims to study the outcome of thoracolumbar burst fractures by comparison of 3 different posterior constructs groups of patients treated by the posterior approach. SettingUniversity level Tertiary care Centre of Northern India. MethodsSingle centre study conducted from September 2020 to April 2022, the study included patients aged 18–50 years with burst fractures in the thoracolumbar region, TLICS score ≥4, and injury surgery duration <3 weeks. Sixty patients were divided into three groups: Group I (short segment with index screw(s) in the fractured vertebrae), Group II (short segment with interbody cage fusion), and Group III (long segment without index screw or interbody cage). Clinical and radiological assessments were performed over a 6-month follow-up period. Outcome measures included the Visual Analog Scale (VAS) for pain, Oswestry Disability Index (ODI), American Spinal Injury Association (ASIA) impairment scale, and radiological parameters. ResultsAmong 60 patients, 38 were male, and 22 were female, with a mean age of 33.37 ± 12.26 years. The most common injury mechanisms were falls from heights (85 %). Group I had the lowest estimated blood loss (395 ± 36.20 ml) and shortest surgery duration (140 ± 26.56 min), while Group III had the highest blood loss (744.25 ± 113.69 ml) and longest surgery duration (203.50 ± 23.40 min). No statistically significant differences were observed in kyphosis correction, canal clearance, or fusion status among the groups. Neurological and functional outcomes improved across all groups, with no significant intergroup differences. ConclusionAll three posterior instrumentation constructs provided effective management of thoracolumbar burst fractures, demonstrating high rates of fusion, significant kyphosis correction, and minimal loss of alignment. Despite variations in surgical parameters such as estimated blood loss and surgery duration, the clinical and radiological outcomes were comparable. Level of evidenceIII.

Effect of screw insertion depth into fractured vertebrae in the treatment of thoracolumbar fractures

PurposeThe study’s objective was to assess the effect of the screw insertion depth into fractured vertebrae in treating thoracolumbar fractures.Materials and methodsThis was a retrospective analysis of 92 patients with thoracolumbar fractures from December 2018 to February 2020. Patients had AO type A2, A3 thoracolumbar fractures. The patients were divided into two groups according to the screw insertion depth. The vertebral wedge angle (VWA), Cobb angle (CA), anterior vertebral body height (AVBH), middle vertebral body height (MVBH), visual analog scale (VAS) score, and Oswestry Disability Index (ODI) were compared preoperatively and at one week and 12 months postoperatively. The correlation between Vertebral height loss and potential risk factors, such as sex, age, BMD and BMI was evaluated.ResultsCompared with the preoperative data, the postoperative clinical and radiographic findings were significantly different in both groups, But no significant difference between the two groups at 1 week. At 1 year postoperatively, there was a significant difference in the CA (p < 0.0001), VWA (p = 0.047), AVBH (p < 0.0001), MVBH (p < 0.0001), VAS score (p < 0.0001), and ODI (p < 0.0001) between the two groups, Except for age, bone density and other influencing factors the long screw group had better treatment results than the short screw group.ConclusionA longer screw provides greater grip on the fractured vertebral body and stronger support to the vertebral plate. The optimal screw placement depth exceeds 60% of the vertebral body length on the lateral view.

Efficacy and safety of short segment pedicle screw fixation in patients with neurologically intact burst fractures of the lower thoracic and lumbar spine: a meta-analysis of studies published over the last 20 years

Objective. To conduct a systematic review and meta-analysis of studies on the surgical treatment of patients with uncomplicated burst fractures of the lower thoracic and lumbar spine and to determine the effectiveness and safety of short transpedicular fixation (TPF) in this patient group.Material and Methods. The study included articles with the following criteria: publication date from January 1, 2004, to December 31, 2023; patient sample descriptions involving uncomplicated burst fractures from T10 to L5; TPF involving one segment adjacent to the fractured vertebra in both cranial and caudal directions without spinal fusion; descriptions of treatment outcomes or complications; and an average follow-up period of at least 12 months. Meta-analysis was conducted using the Comprehensive Meta-Analysis software, version 2.2.064. Depending on the level of heterogeneity (I² test), either a fixed-effects or random-effects model was applied. Begg’s or Egger’s test was used to assess publication bias, and any bias present was corrected using the trim-and-fill method.Results. The application of TPF resulted in a significant reduction in the overall Cobb angle by 5.9 degrees in the percutaneous group and by 7.6 degrees when using a midline approach. Regarding AVBCR (anterior vertebral body compression ratio), a reduction of 24.0 % and 24.8 % was observed in both groups, respectively. The overall complication rates were as follows: superficial infection, 2.2 %; deep infection, 2.0 %; and implant-associated complications, 5.6 %. No patient developed a neurological deficit. The levels of work adaptation W1 and W2 on the Denis scale were achieved in 70.9 % of patients. The overall quality of life, as measured by the Oswestry Disability Index, averaged 13.4 %.Conclusions. Short transpedicular fixation without additional spinal fusion or laminectomy appears to be an effective and safe method for treating burst fractures of the lower thoracic and lumbar spine without neurological deficits. This method allows for regression of kyphotic deformity in the long-term post-injury period by at least 5.9 degrees and restoration of anterior vertebral height by 24 %. The approach demonstrated relatively low overall postoperative complication rates. More than 90 % of patients were able to return to full-time work, either in their previous position or with reduced physical demands.

The value of quantitative analysis of radionuclide bone SPECT/CT imaging in vertebral compression fracture: a retrospective study

BackgroundMost patients with osteoporosis experience vertebral compression fracture (VCF), which significantly reduces their quality of life. These patients are at a high risk of secondary VCF regardless of treatment. Thus, accurate diagnosis of VCF is important for treating and preventing new fractures. We aimed to investigate the diagnostic and predictive value of quantitative bone imaging techniques for fresh VCF.MethodsFrom November 2021 to March 2023, 34 patients with VCF were enrolled in this study, all of whom underwent routine 99mTc-MDP whole-body bone planar scan and local SPECT/CT imaging. The maximum standard uptake value (SUVmax) of 57 fresh VCF, 57 normal adjacent vertebrae, and 19 old VCF were measured. Based on the site of the fracture, fresh VCFs were regrouped into the intervertebral-type group and the margin-type group. Meanwhile, 52 patients who had no bone metastasis or VCFs in their bone scan were assigned to the control group. The SUVmax of 110 normal vertebral bodies and 10 old VCFs in the control group were measured.ResultsThe median SUVmax of fresh VCF was 19.80, which was significantly higher than the SUVmax of other groups. The receiver operator characteristic (ROC) curve showed that the cut-off value of SUVmax was 9.925 for diagnosing fresh VCF. The SUVmax in the intervertebral-type group was significantly higher than that in the margin-type group (P = 0.04). The SUVmax of normal vertebrae was higher among patients than among the control group (P<0.01), but the CT HU value showed no significant difference.ConclusionThe quantitative technique of bone SPECT/CT has a significant value in diagnosing fresh VCF. It can also determine the severity of fractures. In addition, whether the SUVs of the vertebrae adjacent to the fractured vertebra can predict re-fracture deserves further studies.

Safety and efficacy of short percutaneous fixation in AO3 and AO4 lumbar fractures: a single-centre experience of 35 cases.

Spinal fractures with subsequent bone fragment dislocation are among the injuries most feared by patients and physicians. The surgical strategy is tailored to the individual patient's characteristics and often consists of pedicle instrumentation with rod-screw systems. Short instrumentation has been associated with worse spinal correction and increased complications. However, recent studies have suggested similar results in terms of kyphosis correction and the maintenance of sagittal alignment compared to longer instrumentation. This single-center retrospective study was conducted between January 2018 and April 2021. We included 35 single lumbar burst fractures AO Spine grade A3 or A4 with evidence of intra-canal fragments. Patients underwent minimally invasive percutaneous posterior lumbar instrumentation with pedicle screws. Patients received short segmental fixation involving only one level above and below the fractured vertebra. An immediate postoperative computed tomography (CT) scan demonstrated a significant reduction in vertebral kyphotic deformation (11.7° ± 1.6 vs 16.7° ± 5, p<0.001) and sagittal Cobb angle (9.8° ± 1.3 vs 11.7° ± 1.5, p < 0.001). The correction was slightly reduced but remained significant at 12 months for both kyphotic (12.3° ± 1.4, p = 0.03) and sagittal Cobb (10.3° ± 0.9, p = 0.04). Upper lumbar vertebrae showed even larger correction indices compared to lower lumbar segments. No implant failure or screws pullout was seen at the last follow-up. Short spinal fixation is a safe and effective treatment of complete and incomplete burst fractures with posterior bone fragment dislocation. All included patients fared well and achieved good kyphotic correction with no perioperative or long-term complications.

Bone density as a risk of early loss of correction after percutaneous posterior spinal fixation for traumatic thoracolumbar fracture: a study on the usefulness of Hounsfield unit values on computed tomography scan.

Vertebral Hounsfield unit values on computed tomography scan (CT values) have been found to be correlated with bone density measured using dual-energy X-ray absorptiometry. We hypothesized that low preoperative CT values are risk factors for early loss of correction after percutaneous posterior spinal fixation (PPSF). This study aimed to evaluate the usefulness of measuring preoperative CT values. In total, 104 patients underwent PPSF due to traumatic thoracolumbar fracture. Among them, 53 with a range of fixation that was within two vertebrae above and below the fractured vertebra were selected. CT values were measured preoperatively from the most cephalad vertebrae on the fixed vertebrae. Vertebral wedge angle (VWA) and local kyphosis angle (LKA) were measured before and after surgery. participants were classified into progression (P) and nonprogression (NP) groups. The P group comprised patients with LKA progressing > 10° from the immediate postoperative period to 3months postoperatively. Meanwhile, the NP group included patients without progression. Eight (15.1%) patients were included in the P group. The vertebral CT values were 102.2 ± 36.7 in the P group and 162.4 ± 59.7 in the NP group (p < 0.01). The pedicle CT values were 114.4 ± 45.9 in the P group and 170.8 ± 72.3 in the NP group (p < 0.05). At 2weeks postoperatively, VWA and LKA of the P group progressed to 9.8° ± 7.0° and 10.9° ± 7.6°, respectively. CT values can predict progressive loss of correction after PPSF.

Vertebral body density role in determining vertebral osteoporotic fracture type and its progression.

Vertebral osteoporotic fractures (VOF) are among the most frequent fractures in the elderly, often leading to an impaired lifestyle and a high economic burden. Although a reduced bone mass density is considered one of the main risk factors for VOF, its role in determining the fracture type, using the AO spine-DGOU classification for osteoporotic thoracolumbar fractures, as well as its progression, is unknown. The current study aimed to: (1) reveal whether the bone density of the vertebral bodies of fractured and non-fractured vertebrae predicts the type of fracture, (2) examine whether bone density is associated with the initial and progressive collapse of the vertebral body, and (3) provide predictive measures for fracture progression. The study sample included 124 patients (40 males and 84 females) with an acute osteoporotic vertebral fracture who underwent a computerized tomography scan at the time of diagnosis and an x-ray at least 3 months later. The bone density of the fractured and adjacent (non-fractured) vertebrae was measured at diagnosis. The magnitude of the collapse and the progression of the fracture over time were calculated from height measurements of the vertebral bodies at diagnosis and follow-up. Age was a significant factor in predicting the fracture type and magnitude of collapse, whereas sex and bone density were not. The severity of the fracture was involved in predicting its progression, demonstrating that severe-type fractures tended to continue to collapse after diagnosis. However, when each type was examined independently, the density of the fractured vertebra had a protective effect on fracture progression. To conclude, identifying the type of fracture is beneficial in determining patient prognosis. Furthermore, the density of the fractured vertebra, the magnitude of collapse, and patient age are valuable predictors of fracture progression.

Using an Ensemble of Segmentation Methods to Detect Vertebral Bodies on Radiographs.

Vertebral compression fractures may indicate osteoporosis but are underdiagnosed and underreported by radiologists. We have developed an ensemble of vertebral body (VB) segmentation models for lateral radiographs as a critical component of an automated, opportunistic screening tool. Our goal is to detect the approximate location of thoracic and lumbar VBs, including fractured vertebra, on lateral radiographs. The Osteoporotic Fractures in Men Study (MrOS) data set includes spine radiographs of 5994 men aged ≥65 years from 6 clinical centers. Two segmentation models, U-Net and Mask-RCNN (Region-based Convolutional Neural Network), were independently trained on the MrOS data set retrospectively, and an ensemble was created by combining them. Primary performance metrics for VB detection success included precision, recall, and F1 score for object detection on a held-out test set. Intersection over union (IoU) and Dice coefficient were also calculated as secondary metrics of performance for the test set. A separate external data set from a quaternary health care enterprise was acquired to test generalizability, comprising diagnostic clinical radiographs from men and women aged ≥65 years. The trained models achieved F1 score of U-Net = 83.42%, Mask-RCNN = 86.30%, and ensemble = 88.34% in detecting all VBs, and F1 score of U-Net = 87.88%, Mask-RCNN = 92.31%, and ensemble = 97.14% in detecting severely fractured vertebrae. The trained models achieved an average IoU per VB of 0.759 for U-Net and 0.709 for Mask-RCNN. The trained models achieved F1 score of U-Net = 81.11%, Mask-RCNN = 79.24%, and ensemble = 87.72% in detecting all VBs in the external data set. An ensemble model combining predictions from U-Net and Mask-RCNN resulted in the best performance in detecting VBs on lateral radiographs and generalized well to an external data set. This model could be a key component of a pipeline to detect fractures on all vertebrae in a radiograph in an automated, opportunistic screening tool under development.

Shape memory resin with high temperature resistance for plugging fracture formations drilled with oil-based drilling fluid

Lost circulation usually occurs when drilling fracture formations using oil-based drilling fluids (OBDFs). This study synthesized the shape memory epoxy resins (EHN) with a glass transition temperature range of 94–122 °C. They exhibited good thermal stability and dynamical mechanism performance. The EHN did not swell in oil at different temperatures; however, its shape changed with temperature. Optimized by an orthogonal experiment, the thickness swelling rate prepared under the optimal conditions was more than 74%. The particle size reduction rate did not exceed 5% after aging at 150 °C in oil, which was less than 1/4 of that of the nutshell. The EHN1 with a glass transition temperature of 122 °C, prepared under the optimal conditions (OEHN1), was utilized to control lost circulation in OBDF at high temperatures. At a heating rate of 1–10 °C/min, the shape memory rate of OEHN1 required 14–107 min to reach 100% in the temperature range of 30–150 °C, respectively. The shape memory recovery rate of OEHN1 reached to 10, 28, 57, and 97% at 80, 100, 120, and 125 °C within 60 min, respectively. In addition, it required 4–10 min to recover to 100% at 135–150 °C, respectively. OEHN1 did not recover below 80 °C, partially recovered between 80 and 120 °C, and completely recovered above 125 °C (>glass transition temperature). When plugging the wedge fracture with inlet/outlet fracture widths of 3/1 mm at 80–150 °C, formula 2 (F2) containing OEHN1 exhibited lower fluid loss and stabler pressure-bearing capacity under 15 MPa. When plugging the wedge fracture with inlet/outlet fracture widths of 4/2 mm, F2 withstood a pressure of 5 MPa at 80 °C and 15 MPa at 120 °C and 150 °C. Further, OEHN1 exhibited excellent temperature responsiveness and plugging performance. They transformed from the glassy to rubber state following full activation at 125–150 °C. They became elastic particles, expanded from flakes to cubes, and could adapt to different crack sizes. In addition, they bridged, accumulated, filled, and formed compact cracks with other lost circulation materials. Consequently, they formed a force-chain network that improved the stability of the plugging layer.

Unravelling a hidden pathology of a vertebral fracture in a teenage girl

BackgroundAlthough the skeleton remains a common target of primary hyperparathyroidism, the classic bone disease “osteitis fibrosa cystica” is currently rare due to early diagnosis. This case represents severe classic bone manifestations of primary hyperparathyroidism due to delayed diagnosis and delayed medical attention.Case presentationA 19-year-old young female was symptomatically managed for chronic back pain and nonspecific bone pain in the small joints of both hands over 2 months by a general practitioner. The patient had delayed seeking for treatment for 3 months. Later, she was evaluated for tuberculosis, hematological malignancies and rheumatic disorders following a fractured T12 vertebra and underwent pedicle screw fixation. However, clinical examination and investigations, including biochemistry, imaging and histology, ruled out the above conditions. Unfortunately, serum calcium level was not performed at the initial presentation. Later, primary hyperparathyroidism was diagnosed on the basis of moderate hypercalcaemia and elevated intact PTH levels (2064 pg/ml). She had sufficient vitamin D levels and normal kidney function. Her DXA scan revealed severe secondary osteoporosis with the lowest Z score of -8 at the total lumbar spine. Ultrasonography of the thyroid revealed a hypo echoic mass in the left lower neck, and localization studies with technetium-99 m sestamibi and 4D-CT revealed a left inferior parathyroid adenoma (1.6 × 1.5 × 1.6 cm). CT scan also revealed brown tumors in the mandible and vertebrae and diffuse bony changes in the skull, sternum, humerus and vertebrae. Her radiographs revealed subperiosteal bone resorption on the radial aspects of the middle and distal phalanges and brown tumors in both the ulna and fibula. We excluded MEN and other hereditary syndromes in our patient with a personal and family history and with a normal pituitary hormone profile because of poor resources for genetic testing. She underwent parathyroid adenoma excision, and the postoperative period was complicated with hungry bone syndrome, requiring high doses of calcium and active vitamin D supplements. These supplements were gradually weaned off over 6 months, and she recovered with normal biochemical investigations. Histology revealed parathyroid adenoma without malignant features.ConclusionIn developing countries where routine calcium screening is not available, clinicians should be aware of various manifestations of primary hyperparathyroidism to allow diagnosis as soon as possible without delay to prevent further progression, as it is a treatable condition.

Evaluation and analysis of risk factors for adverse events of the fractured vertebra post-percutaneous kyphoplasty: a retrospective cohort study using multiple machine learning models

BackgroundAdverse events of the fractured vertebra (AEFV) post-percutaneous kyphoplasty (PKP) can lead to recurrent pain and neurological damage, which considerably affect the prognosis of patients and the quality of life. This study aimed to analyze the risk factors of AEFV and develop and select the optimal risk prediction model for AEFV to provide guidance for the prevention of this condition and enhancement of clinical outcomes.MethodsThis work included 383 patients with primary osteoporotic vertebral compression fracture (OVCF) who underwent PKP. The patients were grouped based on the occurrence of AEFV postsurgery, and data were collected. Group comparisons and correlation analysis were conducted to identify potential risk factors, which were then included in the five prediction models. The performance indicators served as basis for the selection of the best model.ResultsMultivariate logistic regression analysis revealed the following independent risk factors for AEFV: kissing spine (odds ratio (OR) = 8.47, 95% confidence interval (CI) 1.46–49.02), high paravertebral muscle fat infiltration grade (OR = 29.19, 95% CI 4.83–176.04), vertebral body computed tomography value (OR = 0.02, 95% CI 0.003–0.13, P < 0.001), and large Cobb change (OR = 5.31, 95% CI 1.77–15.77). The support vector machine (SVM) model exhibited the best performance in the prediction of the risk of AEFV.ConclusionFour independent risk factors were identified of AEFV, and five risk prediction models that can aid clinicians in the accurate identification of high-risk patients and prediction of the occurrence of AEFV were developed.

Numerical investigation of proppant transportation characteristics in hydraulically fractured wedge fractures

Hydraulic fracturing creates multiple induced fractures and micro-fractures, forming a complex fracture network in the reservoir. The study of the transport and distribution of the proppant within the fracture network is critical to the design and evaluation. However, existing simulation studies of proppant transport tend to be overly idealized and neglect the inhomogeneity of fracture widths that occur after fracturing. To address these issues, this study employs computational fluid dynamics (CFD) to study the transportation of fracturing fluid and proppant within a fracture network. The flow dynamics of solid-liquid two-phase flow in fractures are simulated using the Euler-Euler multiphase flow model. Considering the actual variables in field construction and the inherent inhomogeneity in realistic fracture structures, a three-dimensional model was established to capture the gradual variation in fracture width. The accuracy of this model was verified through a comparative analysis with physical experiments. On this basis, an investigation was conducted to explore the impact of particle size, particle density, particle volume concentration, and injection velocity on proppant transportation. The results demonstrate that, in contrast to conventional rectangular fractures, sandbanks formed from wedge fractures exhibit a lower height, which facilitates improved transportation into deeper fractures. Furthermore, particle concentration primarily influences distal fractures, with proppant particle size being second. The injection velocity has a significant impact on the height of the sandbank located in proximity to the fracture inlet. The research findings provide a deeper understanding of the transport and distribution of proppants within wedge fractures, thereby establishing a theoretical basis for the analysis and engineering guidance in on-site hydraulic fracturing construction.

Investigation of the Usefulness of Implants With Locking Mechanisms for Diffuse Idiopathic Skeletal Hyperostosis (DISH)-Induced Thoracic and Lumbar Fractures in Patients Operated in the Prone Position.

Background Diffuse idiopathic skeletal hyperostosis (DISH) is a disease that causes bone growth in the spine and musculoskeletal system, and even minor trauma can cause fractures that often require surgery. DISH-induced fractures show a tendency for bone loss when operated in the prone position, which can lead to poor fusion and implant failure; therefore, surgery in the lateral recumbent position is often recommended. However, inserting a pedicle screw (PS) in the lateral recumbent position is technically difficult. This study examined the effectiveness of the repair and fixation of thoracic and lumbar spine fractures using implants with locking mechanisms in the prone position in patients with DISH. Methods We retrospectively analyzed the data from 11 patients (six males and five females; mean age: 87 years) who underwent surgery for thoracic and lumbar fractures caused by DISH between December 2023 and June 2024. Surgery was performed in the prone position using PSs or transdiscal screws (TSDs) for DISH. Ennovate® implants manufactured by B-BRAUN were used. The fixed range was three above-three below for PSs and two above-two below for TSDs. The evaluation parameters were the height/level of injury, operative time, blood loss, local kyphosis angle, anterior wall height ratio, and complications. The local kyphosis angle was measured as the angle between the upper and lower endplates of the fractured vertebrae. The ratio of the anterior wall height was evaluated. Results The average operative time was 87 min (52-172 min), and the average blood loss was 40ml (10-140 ml). The preoperative and postoperative local kyphosis angle was -8.7° and -2.4°, respectively, and the average local kyphosis angle improvement was 6.3° (0.1-14°). The preoperative and postoperative anterior wall height ratio was 132% and 110%, respectively, and the average anterior wall height ratio improvement was 22% (2-82%). No complications, such as screw deviation, implant loosening, loss of correction, or skin problems, were observed. Conclusion This study demonstrated that DISH-induced thoracic and lumbar spine fractures could be repaired and fixed using implants with locking mechanisms in the prone position. The prone position is familiar to spine surgeons and is considered safe. Additionally, screw migration may occur due to decreased bone density in the vertebral bodies with DISH; in such cases, it would be better to fix the screw without forcing it to be repositioned.

Is orthotic treatment beneficial for fresh osteoporotic vertebral fractures? A propensity score matching study

BACKGROUND CONTEXTOrthotic treatment is a common option for the conservative treatment of osteoporotic vertebral fractures (OVF). However, there is insufficient evidence of its clinical benefit. PURPOSETo investigate the effectiveness of orthotic treatment for OVF. STUDY DESIGN/SETTINGRetrospective cohort study with data from two prospective studies. PATIENT SAMPLEThis study included 160 patients with fresh OVF enrolled in 2012 and 2020 prospective cohort studies. OUTCOME MEASURESThe visual analog scale (VAS) score for low back pain was used for clinical outcomes, and radiographic parameters included the percent height of the vertebra and angular change of the vertebral body. Moreover, the occurrence of secondary vertebral fractures was followed-up over time. METHODSThe patients were divided into brace and no-brace groups and were matched according to propensity score for age, sex, anterior percent height at the initial examination, and presence of old OVFs. Hazard ratio for the cumulative incidence of secondary vertebral fractures with and without bracing were calculated and analyzed using the generalized Wilcoxon test. In addition, the brace group was divided into soft and rigid brace groups and compared with the no-brace group. RESULTSEach group had 61 cases after propensity score matching. There were no significant differences in the VAS improvement for low back pain and the change in percent height of the anterior and posterior walls from initial examination to 6 months after injury (p=.87, p=.39 and p=.14, respectively, mixed-effect models). Meanwhile, the mean angular change of fractured vertebrae was 4.3° / 3.2° initially and 1.2° / 2.5° at 6 months (the brace group / no-brace group, respectively; p=.007, mixed-effect models). A significant difference was also observed between the rigid brace group and the no-brace group (p=.008, mixed effect models). The incidence of secondary vertebral fractures was 1.6% / 11.4% at 1 month, indicating a significant difference (the brace group / no-brace group, respectively; p = .028). The hazard ratio for the cumulative incidence of secondary fractures due to orthotic treatment was 0.47 (95% confidence interval 0.20–1.09, p=.054). CONCLUSIONSAlthough orthotic treatment for fresh OVF did not relieve pain, it might contribute to the stabilization of the fractured vertebra, especially using a rigid brace. Moreover, it might influence a reduction of the imminent vertebral fracture risk immediately after the onset of OVF. ClassificationsClinical study

A Prediction Nomogram for Fractured Vertebra Recollapse After Posterior Reduction and Pedicle Screw Fixation in Thoracolumbar Fractures

This study aimed to establish a predictive nomogram model for recollapse of fractured vertebra after posterior pedicle screw fixation in thoracolumbar fractures (TLFs). Patients undergoing posterior pedicle screw fixation for TLFs at our hospital between January 2016 and December 2021 were retrospectively reviewed. Patients were divided into 2 groups according to the presence or absence of recollapse of the fractured vertebra at the final follow-up. The predictors for fractured vertebra recollapse were identified by univariate and multivariable logistic regression analysis, and a nomogram model was developed. The prediction performance and internal validation were established. A total of 224 patients were included in this study. Of these, 46 (20.5%) patients developed recollapse of fractured vertebra. Age, thoracic and lumbar injury severity score, screw distribution in the fractured vertebra, and anterior vertebral height compression ratio were associated with vertebral recollapse. These predictors were used to construct a predictive nomogram. The area under the receiver operating characteristic curve of the nomogram model was 0.891. The concordance index was 0.891, and it was 0.877 with bootstrapping validation. The calibration curves and decision curve analysis also suggested that the nomogram model had excellent predictive performances for fractured vertebra recollapse. A clinical nomogram incorporating 4 variables was constructed to predict fractured vertebra recollapse after posterior pedicle screw fixation for TLFs. The nomogram demonstrated good calibration and discriminative abilities, which may help clinicians to make better treatment decisions.