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Background Context Prevertebral soft tissue swelling (PSTS) after anterior cervical spine surgery (ACSS) has been regarded as one of the critical complications that cause airway obstruction. Still, however, no research has dealt with how PSTS returns to presurgery status after ACSS; most recommendations are being performed without information about its natural course, focusing on acute-phase swelling after surgery. Purpose The study aimed to examine how long postsurgery PSTS lasts and when it returns to its presurgery state, and to analyze the actual influence of a number of factors to observe the natural progress of postsurgery PSTS. Study Design/Setting This is a prospective observational study. Patient Sample The sample included a total of 160 patients who underwent ACSS, including anterior cervical discectomy and fusion (ACDF) and cervical total disc replacement (TDR). Outcome Measures The diameter of PSTS measured at each set time point after surgeries was compared with PSTS measurements before surgery, and analyzed with factors influencing PSTS. Methods Anterior and posterior diameters of the anterior soft tissue of C3 (pharyngeal airway) and C6 (laryngeal airway) were measured using simple lateral radiography before surgery, immediately after surgery, at 2 weeks, 1, 3, 6, and 12 months after surgery. The progress of postsurgery PSTS was analyzed according to patients' individual characteristics, such as age, gender, weight, body mass index (BMI), smoking status, use of antiplatelet therapy, hypertension and diabetes mellitus, complaints of dysphagia, along with surgical factors such as anesthesia time, operation time, numbers of involved operation segments, transfusion, estimated blood loss , and operation method. Multivariable analysis by generalized linear mixed model was used to perform additional univariable analysis on variables found to be related to PSTS. In addition, to find the postsurgery interval at which PSTS naturally stabilizes, repeated measures analysis of variance and Bonferroni method were used to perform post-hoc tests. There were no sources of funding and no conflicts of interest associated with this study. Results For ACDF, the mean values (95% confidence interval [CI]) of PSTS in C3 were 4.38 (4.04~4.71), 10.40 (9.64~11.17), 7.72 (7.10~8.35), 6.24 (5.74~6.69), 5.43 (5.03~5.82), 5.14 (4.77~5.50), and 4.96 (4.59~5.33) mm at each follow-up time, respectively. In C6, the average values (95% CI) of PSTS were 14.43 (13.96~14.91), 19.18 (18.59~19.77), 17.92 (17.37~18.47), 16.98 (16.45~17.51), 16.18 (15.67~16.69), 15.95 (15.50~16.40), and 15.49 (15.50~16.40) mm. For cervical TDR, the mean values (95% CI) of PSTS in C3 were 3.67 (3.45~3.89), 8.05 (7.17~8.93), 5.42 (4.92~5.91), 4.57 (4.21~4.92), 4.12 (3.99~4.36), 4.10 (3.87~4.34), and 3.90 (3.66~4.14) mm at each follow-up time, respectively. In C6, the average values (95% CI) of PSTS were 13.61 (12.96~14.25), 16.51 (15.80~17.21), 15.77 (15.13~16.42), 15.24 (14.61~15.87), 14.62 (14.01~15.22), 14.52 (13.88~15.17), and 13.94 (13.20~14.68) mm. It is discovered that PSTS after surgery returned to presurgery status within 1 to 3 months in the pharyngeal airway (C3) and within 3 to 6 months in the laryngeal airway (C6), and gender, BMI, and surgery method (ACDF) were determined to be the factors having influence on PSTS after surgery. Conclusions It is necessary to pay attention to PSTS and patient conditions after ACSS for at least 1 to 6 months postsurgery, depending on surgical method and operation levels.

While the tensile strength and elongation obtained for medium Mn steel would appear to make it a candidate material in applications which require formable ultra-high strength materials, many secondary aspects of the microstructure–properties relationships have not yet been given enough attention. In this contribution, the microstructural and tensile properties of medium Mn steel with a bimodal microstructure consisting of an ultra-fine grained ferrite + austenite constituent and coarse-grained delta-ferrite are therefore reviewed in detail. The tensile properties of ultra-fine-grained intercritically annealed medium Mn steel reveal a complex dependence on the intercritical annealing temperature. This dependence is related to the influence of the intercritical annealing temperature on the activation of the plasticity-enhancing mechanisms in the microstructure. The kinetics of deformation twinning and strain-induced transformation in the ultra-fine grained austenite play a prominent role in determining the strain hardening of medium Mn steel. While excellent strength–ductility combinations are obtained when deformation twinning and strain-induced transformation occur gradually and in sequence, large elongations are also observed when strain-induced transformation plasticity is not activated. In addition, the localization of plastic flow is observed to occur in samples after intercritical annealing at intermediate temperatures, suggesting that both strain hardening and strain rate sensitivity are influenced by the properties of the ultra-fine-grained austenite.

In the present study, the damage mechanisms operating during the tensile deformation of intercritically annealed Fe-0.3%C-6.0%Mn-3%Al-1.5%Si medium Mn steel were investigated. The steel was annealed at different temperatures to obtain a range of strain hardening properties in uniaxial tension by activating the twinning-induced plasticity and transformation-induced plasticity effects. The initial microstructure consisted of coarse δ-ferrite grains and an ultra-fine grained (UFG) constituent containing ferrite (α) and austenite (γ). However, the volume fraction of martensite (α′) increased significantly by phase transformation from austenite as the material deformed plastically. The internal damage and the fracture appearance after monotonic standard uniaxial tension tests and in-situ interrupted tensile experiments were characterized at macro- and micro-scale. The fracture features were analyzed as a function of the intercritical annealing temperature, which is the most important processing parameter for medium Mn steel. Three mechanisms contributed to the damage that developed in these materials. First, nucleation and growth of voids occurred at non-metallic inclusions. Second, debonding of the α-α′ and α′-α′ interfaces due to a local loss of interfacial strength was observed in the UFG constituent. While the voids initiated at non-metallic inclusions were in the order of several microns, the size of those initiated at the α-α′ and α′-α′ interfaces in the UFG constituent was limited by the initial grain size, with little or no growth. Finally, in addition to void damage, longitudinal cleavage-like cracks formed along the δ-ferrite layers, and parallel to the sheet plane, were observed in the fractured specimens. These longitudinal cleavage-like cracks were the consequence, but not the cause, of a fracture process triggered by plastic flow localization during uniaxial tension testing.

Our study aimed to confirm the correlation between the Cranial Sagittal Vertical Axis (CrSVA) and patient-reported outcomes and to compare clinical correlation between CrSVA and C7 SVA in adult spinal deformity (ASD) patients. 108 consecutive ASD patients were evaluated using the EOS® 2D/3D radio-imaging device. A vertical plumb line from the cranial center was utilized to measure the distance to the posterior corner of S1 (CrSVA-S), and to the centers of the hip (CrSVA-H), the knee (CrSVA-K), and ankle (CrSVA-A), as well as measuring the standard C7 SVA. We analyzed the correlation between each CrSVA parameter with the Oswestry Disability Index (ODI) and Scoliosis Research Society form (SRS-22r). All 4 CrSVA measures demonstrated strong correlation with the ODI and SRS-22r total score and the pain, self-image, and function subscores. Of note, CrSVA-A (Global SVA) also strongly correlated with the SRS satisfaction subscore. Univariate linear regression showed similar results. The strongest predictor of outcomes was CrSVA, not C7 SVA; (CrSVA-H for ODI, SRS total score, and the pain, self-image, and function subscores; and Global SVA for satisfaction and mental health subscores). The clinical correlation effect of outcome scores to the CrSVA measures is validated. Global SVA has an especially strong correlation with ODI and all the SRS subscores. Our study confirms that CrSVA is a stronger predictor of preoperative clinical outcomes than the C7 SVA in adult deformity patients.

Background While hemiarthroplasty (HA) is considered the treatment of choice for displaced femoral neck (FN) fractures in elderly patients, HA has been partly performed as an alternative treatment option for unstable intertrochanteric (IT) fractures. However, there is a paucity of data regarding the risk and availability of HA for unstable IT fractures compared to HA for displaced FN fractures in elderly patients. Therefore, we performed this case-control study to determine whether HA for unstable IT fractures provides clinical results and survival comparable to HA for displaced FN fractures in elderly patients. Hypothesis HA for unstable IT fractures in elderly patients provides clinical results and 1-year survival comparable to HA for displaced FN fractures in the same aging group. Materials and methods We identified 80 patients aged 75 years or older, who underwent cementless bipolar HA for unstable IT fracture (AO/OTA type 31-A2.2/3 and A3.3). Their clinical results and 1-year survival were compared to the matched control group of 80 patients with displaced FN fractures (Garden type 3 and 4) treated with the same procedure. Perioperative results, postoperative complications, and 1-year survival were investigated between the two groups. Functional outcome was assessed by walking status and Harris hip score (HHS) 6 months after surgery. Results Operating time was significantly longer in the IT group than the FN group (97.3 min [50 to 255] vs. 79.3 min [40 to 175], P = 0.016). However, the two groups did not significantly differ regarding perioperative results, such as total blood loss, transfusion, intraoperative fracture, length of hospital stay, and postoperative complication. No statistically significant differences in walking status and HHS were observed between the groups. No significant difference in cumulative survival was observed between the two groups (P = 0.836), with a 1-year survival rate of 80% (95% confidence interval [CI], 71.8 to 87.5) in the IT group and 82% (95% CI, 73.1 to 89.4) in the FN group. Conclusion HA for unstable IT fractures in elderly patients showed clinical results and 1-year survival comparable to HA as the treatment of choice for displaced FN fractures in the same aging group. Level of evidence Level III, case-control study.

To assess the clinical and radiologic outcome of osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture (SPF) without posterior ligament injury. A total of 391 patients with single-level osteoporotic thoracolumbar junctional (T10-L2) fracture were selectively enrolled. The patients were divided into two groups by absence (group I) or presence (group II) of SPF. Clinical and radiologic parameters were compared between the two groups. Group I comprised of 332 patients with only vertebral body fracture, and group II comprised of 59 patients with both vertebral body and SPFs. In all cases of group II, SPFs were located just one level above the fractured vertebral body, and the injury of the posterior ligament was not found. At the time of injury, group II patients showed worse outcomes in anterior vertebral body compression percentage, kyphotic Cobb angle, cranial disk status, and the rate of the initial neurologic injury. Kyphotic alignment changes during 1-year follow-up were compared between the conservative subgroups of groups I and II. At the time of injury, there were no statistical differences in anterior vertebral body compression percentage and Cobb angle between the two conservative subgroups. However, the difference was significant after 1-year follow-up. Comparison of kyphotic alignment change at 12 months after diagnosis within group II was done according to the treatment method. Vertebroplasty subgroup in group II did not show benefit even in preventing such kyphotic alignment change, whereas instrumentation subgroup in group II showed lordotic alignment restoration despite more severe kyphotic alignment at the time of injury. Osteoporotic thoracolumbar junctional fracture accompanied by spinous process fracture without posterior ligament injury represented more severe injury with flexion forces on the anterior column and tensile forces on the posterior column, and was related with more severe posttraumatic kyphotic changes during the 12-month follow-up.

In this study, microstructures of a heat-affected zone (HAZ) of an SA 508 steel were identified by Mossbauer spectroscopy in conjunction with microscopic observations, and were correlated with fracture toughness. Specimens with the peak temperature raised to 1350 °C showed mostly martensite. With the peak temperature raised to 900 °C, the martensite fraction was reduced, while bainite or martensite islands were formed because of the slow cooling from the lower austenite region and the increase in the prior austenite grain size. As the martensite fraction present inside the HAZ increased, hardness and strength tended to increase, whereas fracture toughness decreased. The microstructures were not changed much from the base metal because of the minor tempering effect when it was raised to 650 °C or 700 °C. However, fracture toughness of the subcritical HAZ with the peak temperature raised to 650 °C to 700 °C was seriously reduced after postweld heat treatment (PWHT) because carbide particles were of primary importance in initiating voids. Thus, the most important microstructural factors affecting fracture toughness were the martensite fraction before PWHT and the carbide fraction after PWHT.

Background While hemiarthroplasty (HA) is considered the treatment of choice for displaced femoral neck (FN) fractures in elderly patients, HA has been partly performed as an alternative treatment option for unstable intertrochanteric (IT) fractures. However, there is a paucity of data regarding the risk and availability of HA for unstable IT fractures compared to HA for displaced FN fractures in elderly patients. Therefore, we performed a case control study to determine: 1) whether HA for unstable IT fractures provides clinical results and survival comparable to HA for displaced FN fractures. Hypothesis HA for unstable IT fractures in elderly patients provides clinical results and 1-year survival comparable to HA for displaced FN fractures in the same aging group. Materials and methods We identified 80 patients aged 75 years or older, who underwent cementless bipolar HA for unstable IT fracture (AO/OTA type 31-A2.2/3 and A3.3). Their clinical results and 1-year survival were compared to the matched control group of 80 patients with displaced FN fractures (Garden type 3 and 4) treated with the same procedure. Perioperative results, postoperative complications, and 1-year survival were investigated between the two groups. Functional outcome was assessed by walking status and Harris hip score (HHS) 6 months after surgery. Results Operating time was significantly longer in the IT group than the FN group (97.3 min [50 to 255] vs. 79.3 min [40 to 175], P = 0.016). However, the two groups did not significantly differ regarding perioperative results such as total blood loss, transfusion, intraoperative fracture, length of hospital stay, and postoperative complication. No statistically significant differences in walking status and HHS were observed between the groups. No significant difference in cumulative survival was observed between the two groups (P = 0.836), with a 1-year survival rate of 80% (95% confidence interval [CI], 71.8 to 87.5) in the IT group and 82% (95% CI, 73.1 to 89.4) in the FN group. Conclusion HA for unstable IT fractures in elderly patients showed clinical results and 1-year survival comparable to HA as the treatment of choice for displaced FN fractures in the same aging group. Level of evidence Level III, case-control study.