Explore the vast range of titles available.

A comparative analysis of three transversely isotropic hyperelastic constitutive laws is presented to characterize the mechanical behavior of spinal ligaments within finite element simulations. In each material model, the total strain energy is partitioned into ground‑matrix and fiber contributions. The ground‑matrix response was represented by three strain‑energy functions, Neo‑Hookean, Mooney‑Rivlin, and Yeoh, whereas the fiber response was captured by a fourth‑order polynomial. Constitutive parameters were calibrated against experimental uniaxial tension data from human thoracic spinal ligaments. The models were implemented via user‑defined material subroutines in Abaqus and LS‑Dyna and evaluated with finite shell elements. Performance of the afore-mentioned constitutive laws was assessed based on their ability to fit experimental data and their computational efficiency. The results indicate that, although the Yeoh model provides the best fit to the experimental data in terms of root mean square error, it tends to underestimate the fiber contribution to the overall material response, resulting in an over-stiffening effect in simulations of short-sample tensile tests. In contrast, the Neo-Hookean and Mooney-Rivlin models do not exhibit this issue.

Many daily activities involve hand-behind-back (HBB) movements, which are often difficult for patients with chronic shoulder pathologies. HBB movements involve upper-limb and scapular motions. However, thoracic spine motions during the HBB movements and the effects of thoracic spine alignment on the HBB movement kinematics remain uninvestigated. This study aimed to examine the upper-limb, scapular, and thoracic spine motions during HBB movements by using a three-dimensional motion analysis system. Twenty healthy young adults were included (10 women and 10 men, mean age = 22.8 years). HBB movement measurements started while the participants stood with their palms facing forward. They then placed their hands behind their buttocks, with their palms facing backward. Almost all participants exhibited elbow flexion, shoulder extension, abduction, internal rotation, and scapular anterior tilt during the HBB movement. The scapular upward/downward rotation differed between the participants. Scapular, shoulder, and elbow motions showed significant correlations, suggesting that the HBB movements from the arms positioned on the side to the hands placed behind the buttocks involve complex coordinated motions of the shoulder, elbow, and scapula. Several participants exhibited little thoracic motion, whereas the others flexed their thoracic spine. Individuals with a smaller thoracic flexion motion tended to have a larger initial thoracic flexion angle before the HBB movement. The initial thoracic flexion angle and thoracic flexion motion did not correlate with the scapular, shoulder, or elbow motion; thus, healthy young adults with little thoracic flexion did not use specific compensation strategies during the HBB movements until the hands reached the buttocks.

Osteoporosis is under-diagnosed while detectable by measuring bone mineral density (BMD) using quantitative computer tomography (QCT). Opportunistic screening for low BMD has previously been suggested using lumbar QCT. However, thoracic QCT also possesses this potential to develop upper and lower cut-off values for low thoracic BMD, corresponding to the current cut-offs for lumbar BMD. In participants referred with chest pain, lumbar and thoracic BMD were measured using non-contrast lumbar- and cardiac CT scans. Lumbar BMD cut-off values for very low (< 80 mg/cm3), low (80–120 mg/cm3), and normal BMD (> 120 mg/cm3) were used to assess the corresponding thoracic values. A linear regression enabled identification of new diagnostic thoracic BMD cut-off values. The 177 participants (mean age 61 [range 31–74] years, 51% women) had a lumbar BMD of 121.6 mg/cm3 (95% CI 115.9–127.3) and a thoracic BMD of 137.0 mg/cm3 (95% CI: 131.5–142.5), p < 0.001. Categorization of lumbar BMD revealed 14%, 35%, and 45% in each BMD category. When applied for the thoracic BMD measurements, 25% of participants were reclassified into a lower group. Linear regression predicted a relationship of Thoracic BMD = 0.85 * Lumbar BMD + 33.5, yielding adjusted thoracic cut-off values of < 102 and > 136 mg/cm3. Significant differences in BMD between lumbar and thoracic regions were found, but a linear relationship enabled the development of thoracic upper and lower cut-off values for low BMD in the thoracic spine. As Thoracic CT scans are frequent, these findings will strengthen the utilization of CT images for opportunistic detection of osteoporosis.

ObjectiveTo compare the costotransversectomy (CTV) and transpedicular (TP) approaches versus the transfacet (TF) approach for the surgical treatment of calcific thoracic spine herniations (cTDH), in terms of surgical and clinical outcomes.BackgroundSurgical approaches for cTDH are debated. Anterior approaches are recommended, while posterolateral approaches are preferred for non-calcific, paramedian, and lateral hernias. Currently, there is limited evidence about the superiority of a more invasive surgical approach, such as CTV or TP, over TF, a relatively less invasive approach, in terms of neurological outcome, pain, and surgical complications, for the treatment of cTDH.MethodsA retrospective, observational, monocentric study was conducted on patients who underwent posterolateral thoracic approaches for symptomatic cTDH, between 2010 and 2023, at our institute. Three groups were drafted, based on the surgical approach used: TF, TP, and CTV. All procedures were assisted by intraoperative CT scan, spinal neuronavigation, and intraoperative neuromonitoring. Analyzed factors include duration of surgery, amount of bone removal, intraoperative blood loss, CSF leak, need of instrumentation for iatrogenic instability, degree of disc herniation removal, myelopathy recovery.Afterwards, a statistical analysis was performed to investigate the bony resection of the superior posterior edge of the vertebral soma. The primary outcome was the partial or total herniation removal.ResultsThis study consecutively enrolled 65 patients who underwent posterolateral thoracic surgery for cTDH. The TF approach taking the least, and the CTV the longest time (p < 0.01). No statistical difference was observed between the three mentioned approaches, in terms of intraoperative blood loss, dural leakage, post-resection instrumentation, total herniation removal, or myelopathy recovery. An additional somatic bony resection was successful in achieving total herniation removal (p < 0.01), and the extent of bony resection was directly proportional to the extent of hernia removal (p < 0.01).ConclusionsNo statistically significant differences were highlighted between the TP, TF, and CTV regarding the extent of cTDH removal, the postoperative complications, and the neurological improvement. The described somatic bone resection achieved significant total herniation removal and was directly proportional to the preop against postop anteroposterior diameter difference.

Purpose Thoracic disc herniations are uncommon and carry a high risk for neurological deterioration. Traditional surgical approaches include thoracotomy, costotransversectomy or posterior approaches with considerable morbidity. In this technical note with case series, we describe a minimally invasive tubular retractor–assisted retropleural approach for simple and less invasive microsurgical exploration of thoracic disc herniations from a lateral angle. Methods Surgical technique consisted of partial rib resection and retropleural dissection followed by the placement of a tubular retractor (METRx Tubes, Medtronic) for an anterior-lateral exposure of the disc and neuroforamen. Epidemiological, clinical and surgical patient data were acquired. Results Between 2017 and 2020, six patients were surgically treated using the minimally invasive tubular retractor–assisted retropleural approach. Microsurgical exposure of the disc and neural structures was achieved from a lateral direction without requiring thoracotomy or lung deflation. Control imaging confirmed resection in all cases without relevant residuum. As postoperative complications, one dural injury and one postoperative pneumothorax occured. No neurologic deterioration or recurrence occurred during a median follow-up of 3 months. Conclusion The described tubular retractor–assisted retropleural exposure serves as a feasible minimally invasive microsurgical approach to the anterior-lateral thoracic spine.

Purpose To determine the impact of magnetic resonance imaging (MRI) on fracture classification for thoracic spine fractures (TSFs) compared to computed tomography (CT) alone. Methods This study was a retrospective review of 63 consecutive patients with TSFs who underwent CT and MRI within ten days of injury. Three reviewers classified all fractures according to the AOSpine Classification and the Thoracolumbar AOSpine Injury severity score (TLAOSIS). Posterior ligamentous complex (PLC) injury on MRI was defined by “black stripe discontinuity” and on CT by the presence of vertebral body translation, facet joint malalignment, horizontal laminar or spinous process fracture, and interspinous widening. The proportion of patients with AO type A/B/C and with TLAOSIS ≤ 5 and ≥ 6 was compared between CT and MRI. Classification and regression trees were used to create a series of predictive models for the probability of PLC injury in AO type A fractures. Results AO classification using CT was as follows: type A in 35 patients (55%), type B in 18 patients (29%), and type C in 10 patients (16%). Thirty-three patients (52%) had a TLAOSIS ≤5, while the remaining 30 (48%) had TLAOSI ≥6. The addition of MRI after CT upgraded type A to type B fractures in 10 patients (16%) and changed TL AOSIS from ≤5 to ≥6 in 8 cases (12.8%). Type A fractures with load sharing score (LSC) ≥6 had a 60% chance of upgrading to type B, while LSC <6 had a 12.5% chance of upgrading to type B. Conclusions CT yielded (89%) accuracy in diagnosing PLC injury in TSFs. The addition of MRI after CT substantially changed the AO classification or TLAOISS, compared to CT alone, thus suggesting an added value of MRI for PLC assessment for TSFs classification.

PurposeTo investigate the risk factors for thoracic ossification of the ligamentum flavum (TOLF), especially the relationship between BMI and TOLF.MethodsA total of 856 individuals consisting of 326 controls without ossification of spinal ligaments and 530 TOLF inpatients who underwent thoracic spine decompression surgery at our hospital between January 2013 and September 2020 were included. All subjects were classified into 4 grades: Grade 0) control; Grade 1) single-segment TOLF; Grade 2) multi-segment TOLF; and Grade 3) TOLF combined thoracic ossification of the posterior longitudinal ligament (T-OPLL). Logistic regression analysis was performed to identify the risk factors for TOLF. The TOLF index was calculated to assess the severity of TOLF, and its relationship with BMI was investigated by correlation analysis.ResultsOverall, TOLF patients are most numerous in the 50–59 age group. Age and gender were considered as independent risk factors for Grades 1 and 2. BMI was identified as an independent risk factor for TOLF. Furthermore, BMI was significantly higher in Grade 1 (26.1 VS 24.5 kg/m2, P = 0.0001), Grade 2 (28.2 VS 24.5 kg/m2, P < 0.0001), and Grade 3 (29.1 VS 24.5 kg/m2, P < 0.0001) than Grade 0. Notably, in TOLF patients without combined T-OPLL, BMI was positively correlated with TOLF index, while BMI was negatively correlated with age in younger individuals.ConclusionBMI is a crucial risk factor for TOLF. It highlights the necessity of close follow-up of asymptomatic TOLF patients with high BMI to detect and treat their TOLF progression promptly.

PurposeFor ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine, anterior decompression is the most effective method for relieving spinal cord compression. The purpose of this study was to prospectively analyze the surgical outcomes based on our strategy in the treatment of thoracic OPLL.MethodsThis study included 23 patients who underwent surgery for thoracic OPLL based on the following strategy between 2011 and 2017. For patients with a beak-type OPLL in the kyphotic curve with a ≥ 50% canal occupying ratio, circumferential decompression via a posterolateral approach and fusion (CDF) was indicated. For other types of OPLL, posterior decompression and fusion (PDF) was commonly indicated. Posterior fusion without decompression (PF) was applied when the spinal cord was separated from the posterior spinal elements. Clinical and radiological outcomes were compared among the CDF, PDF, and PF groups with a minimum of 20-month follow-up.ResultsTen, eleven, and two patients underwent CDF, PDF, and PF, respectively. The preoperative Japanese Orthopedic Association (JOA) score in the CDF group was significantly lower than that in the PDF group. The average recovery rate, according to JOA score, was 63%, 56%, and 25% in the CDF, PDF, and PF groups, respectively. The result in the CDF group was better than that in the PF group.ConclusionsAnterior decompression was appropriate for patients with localized spinal cord compression by a large OPLL in the kyphotic curve, and CDF via a posterolateral approach appears to be safe and effective.Graphic abstractThese slides can be retrieved under Electronic Supplementary Material.

Fauna of flies on pig carcasses and bones and their emergence succession were investigated in Hokkaido, Japan. A total of 55,937 flies consisting 23 identified species in 16 families was collected from emergence traps after removal of carcasses and emergence containers containing bones. In emergence traps, Lucilia caesar (Linnaeus) emerged earliest, followed by Hydrotaea ignava (Harris). Piophilid flies emerged 22–25 days later than L. caesar, and their emergence periods were prolonged. In emergent flies from bones, Piophilidae was the dominant family, comprising five species; Stearibia nigriceps (Meigen) was the most abundant, followed by Liopiophila varipes (Meigen) and Protopiophila latipes (Meigen). Stearibia nigriceps and L. varipes remarkably dominated in summer bones and overwintering spring bones, respectively. Piophilids emerged from all 11 types of bones; the thoracic spine significantly yielded the most numerous individuals in S. nigriceps. The developmental duration of larvae of S. nigriceps in bones was estimated to be 12–34 days after placement of carcasses in summer. Observations of overwintering bones showed that L. varipes and Centrophlebomyia grunini (Ozerov) overwintered in larvae inside of bones. The importance of examining piophilid larvae in bones and their potential forensic usefulness are discussed. •In emergent flies from bones, Piophilidae was the dominant family, comprising five species.•Stearibia nigriceps and Liopiophila varipes remarkably dominated in summer bones and overwintering bones, respectively.•Piophilids emerged from all 11 types of bones; the thoracic spine yielded the most numerous individuals in S. nigriceps.•Duration of larvae of S. nigriceps in bones was estimated to be 12–34 days after placement of carcasses in summer.•Most of L. varipes and Centrophlebomyia grunini overwintered in larvae inside of bones.

The OF5 type of vertebral osteoporotic fracture (AO Spine-DGOU classification) represents a three-column lesion and as such is considered as highly unstable. These lesions, however, tend to affect elderly, frail patients, in whom invasive management options are limited. The stent-screw-assisted internal fixation (SAIF) technique has previously been reported as a minimally invasive treatment for osteoporotic and neoplastic vertebral fractures. Here, we sought to assess the safety and efficacy of the SAIF technique in a retrospective series of patients with thoracic OF5-fractures. Retrospective identification, in a prospectively maintained database, of patients with OF5-fractures treated with SAIF. Intra- and post-operative complications were reported. Clinical outcome using NRS pain scale and Patient’s Global Impression of Change (PGIC) and radiological outcome, with local kyphotic angle (LKA) and VB height (VBH) correction were analyzed. N = 22 consecutive patients were identified. All fractures were located in the thoracic spine. No intra-procedural complications occurred, although hospitalization-related complications did occur in 2 patients (9 %). There was a statistically significant pain reduction on follow-up. VBH restoration range was 0–12 mm (mean 5.5 mm). The mean postoperative LKA correction was 7.5°, which was maintained at last follow-up. The SAIF technique appears to be a viable alternative in the management of OF5-fractures. Although it does not address all elements of OF5 instability, it appears that the stabilisation of the anterior and middle vertebral columns, coupled with the stabilising effect of the ribcage in the hypomobile thoracic spine, are biomechanically sufficient to treat OF5-fractures in this section of the spine. •Osteoporotic fractures continue to increase in incidence due to an ageing population.•Treatment solutions that offer less extensive surgery reducing risks are essential.•Type OF5 represent the most unstable osteoporotic fractures.•Surgery goals: pain treatment, restore vertebral body height, correct deformity, provide stability.•SAIF is a compromise that reduces procedural risks, complications while achieving surgical goals.