Efficacy of anti-suppression therapy in improving binocular vision in children with small-angle Esotropia

Purpose: To evaluate the efficacy of anti-suppression exercises in children with small-angle esotropia in achieving binocular vision. Methods: A retrospective review of patients aged 3–8 years who underwent anti-suppression exercises for either monocular or alternate suppression between January 2016 and December 2021 was conducted. Patients with esotropia less than 15 prism diopters (PD) and visual acuity ≥ 6/12 were included. Patients with previous intra-ocular surgery or less than three-month follow-up were excluded. Success was defined as the development of binocular single vision (BSV) for distance, near, or both (measured clinically with either the 4 prism base out test or Worth four dot test) and maintained at two consecutive visits. Qualified success was defined as the presence of diplopia response for both distance and near. Additionally, improvement in near stereo acuity was measured using the Stereo Fly test. Results: Eighteen patients with a mean age of 5.4 ± 1.38 years (range 3–8 years) at the time of initiation of exercises were included in the study. The male female ratio was 10:8. The mean best corrected visual acuity was 0.18 LogMAR unit(s) and the mean spherical equivalent was +3.8 ± 0.14 diopters (D). The etiology of the esotropia was fully accommodative refractive esotropia (8), microtropia (1), post–operative infantile esotropia (4), partially accommodative esotropia (1), and post-operative partially accommodative esotropia (4). Patients received either office-based, home-based, or both modes of treatment for an average duration of 4.8 months (range 3–8). After therapy, BSV was achieved for either distance or near in 66.6 % of patients (95 % CI = 40.03–93.31 %). Binocular single vision for both distance and near was seen in 50 % of children. Qualified success was observed in 38.46% of patients. Persistence of suppression was observed in one patient (5.5 %)... (AU)

Postoperative early weight-bearing using double plating for periprosthetic, interprosthetic, and interimplant distal femur fractures following total knee arthroplasty: A report of three cases.

Background: Distal femur fractures (DFFs) following total knee arthroplasty (TKA) in older patients often require prolonged non-weight-bearing, thereby decreasing their activities of daily living (ADL) and increasing mortality. This report clarifies early weight-bearing safety and utility by using double-plate fixation on medial and lateral sides (LM180 double-plate fixation) for DFFs following TKA. Case presentation: Three cases of Su Type III periprosthetic, interprosthetic, and interimplant DFFs following TKA, where bone stock was limited, were treated with LM180 double-plate fixation using locking plates through medial and lateral incisions on the distal femur. In interprosthetic and interimplant DFF cases, the proximal section was secured by overlapping the lateral plate +/- medial plate with the proximal femur stem of the intramedullary nail by using monocortical screws and cerclage wires. Early postoperative partial weight-bearing was recommended, and full weight-bearing was allowed 4-5 weeks postoperation. All cases regained independent walking without hardware failure. Average ADL scores, namely, Barthel index (BI) and functional independence measure (FIM), were recovered to 85/100 and 114.7/126, respectively, approaching near-normal values. Conclusion: LM180 double-plate fixation for DFFs such as Su Type III periprosthetic, Vancouver type C interprosthetic, and interimplant DFFs following TKA with limited bone stock can be used to achieve early weight-bearing without fixation failure and help maintain ADL.

Non-native Pathway Engineering with CRISPRi for Carbon Dioxide Assimilation and Valued 5-Aminolevulinic Acid Synthesis in Escherichia coli Nissle.

Carbon dioxide emission and acidification during chemical biosynthesis are critical challenges toward microbial cell factories' sustainability and efficiency. Due to its acidophilic traits among workhorse lineages, the probiotic Escherichia coli Nissle (EcN) has emerged as a promising chemical bioproducer. However, EcN lacks a CO2-fixing system. Herein, EcN was equipped with a simultaneous CO2 fixation system and subsequently utilized to produce low-emission 5-aminolevulinic acid (5-ALA). Two different artificial CO2-assimilating pathways were reconstructed: the novel ribose-1,5-bisphosphate (R15P) route and the conventional ribulose-5-phosphate (Ru5P) route. CRISPRi was employed to target the pfkAB and zwf genes in order to redirect the carbon flux. As expected, the CRISPRi design successfully strengthened the CO2 fixation. The CO2-fixing route via R15P resulted in high biomass, while the engineered Ru5P route acquired the highest 5-ALA and suppressed the CO2 release by 77%. CO2 fixation during 5-ALA production in EcN was successfully synchronized through fine-tuning the non-native pathways with CRISPRi.

The Results of Hook Plate Fixation in Acute Acromioclavicular Joint Dislocation and Distal Clavicle Fractures.

Background: Acromioclavicular joint (ACJ) dislocation and distal clavicle fractures are common shoulder injuries. Different methods of fixation are used to treat such injuries, each has its advantages and disadvantages. In this study, we tested fixation using the hook plate. We think that it is technically simple, reliable and more effective in certain surgical situations. However, it is not gaining adequate popularity due to the potential complications of the plate placement including subacromial osteolysis, impingement, rotator cuff injury and others. A second surgery for plate removal is classically indicated to cope with such complications. Objective: The aim of this study included evaluating the clinical and radiological healing after hook plate fixation in ACJ dislocation and distal clavicle fractures and assessing the incidence and clinical significance of subacromial osteolysis. Methods: It is a prospective observational study with a total of 96 cases including 64 ACJ dislocations and 32 distal clavicle fractures. Constant-Murley score was used for clinical evaluation. The patients were evaluated regularly with a minimum follow up of 12 months after plate removal. Results: At the end of the study we found that the results of the hook plate fixation for both groups were good clinically and radiologically. The clinical result score was found to be initially higher among the patients of the ACJ dislocation mainly due to the earlier plate removal in these patients. However, the final score was found to be comparable in both groups. The incidence of the subacromial osteolysis was found to be higher among the patients with clavicle fractures as the plate was retained for a longer time. However we found that subacromial osteolysis did not imply any increased rate of symptoms over the patients who did not show this complication on the X-ray. Conclusion: Based on these observations, we recommend the hook plate fixation to be added to the armamentarium of the orthopaedic surgeon treating such injuries as it is simple to implement, durable and capable of dealing with difficult situations. The main disadvantage of this method is the need for a second surgery for plate removal.

Perioperative and safety outcomes following tissue-sparing posterior cervical fusion to revise a pseudarthrosis: A multicenter retrospective review of 150 cases.

Background: Posterior cervical fusion (PCF) with lateral mass screws is a favorable treatment option to revise a symptomatic pseudarthrosis due to reliable rates of arthrodesis; however, this technique introduces elevated risk for wound infection and hospital readmission. A tissue-sparing PCF approach involving facet fixation instrumentation reduces the rates of postoperative complications while stabilizing the symptomatic level to achieve arthrodesis; however, these outcomes have been limited to small study cohorts from individual surgeons commonly with mixed indications for treatment. Materials and Methods: One hundred and fifty cases were identified from a retrospective chart review performed by seven surgeons across six sites in the United States. All cases involved PCF revision for a pseudarthrosis at one or more levels from C3 to C7 following anterior cervical discectomy and fusion (ACDF). PCF was performed using a tissue-sparing technique with facet instrumentation. Cases involving additional supplemental fixation such as lateral mass screws, rods, wires, or other hardware were excluded. Demographics, operative notes, postoperative complications, hospital readmission, and subsequent surgical interventions were summarized as an entire cohort and according to the following risk factors: age, sex, number of levels revised, body mass index (BMI), and history of nicotine use. Results: The average age of patients at the time of PCF revision was 55 ± 11 years and 63% were female. The average BMI was 29 ± 6 kg/m2 and 19% reported a history of nicotine use. Postoperative follow-up visits were available with a median of 68 days (interquartile range = 41-209 days) from revision PCF. There were 91 1-level, 49 2-level, 8 3-level, and 2 4±-level PCF revision cases. The mean operative duration was 52 ± 3 min with an estimated blood loss of 14 ± 1.5cc. Participants were discharged an average of 1 ± 0.05 days following surgery. Multilevel treatment resulted in longer procedure times (single = 45 min, multi = 59 min, P = 0.01) but did not impact estimated blood loss (P = 0.94). Total nights in the hospital increased by 0.2 nights with multilevel treatment (P = 0.01). Sex, age, nicotine history, and BMI had no effect on recorded perioperative outcomes. There was one instance of rehospitalization due to deep-vein thrombosis, one instance of persistent pseudarthrosis at the revised level treated with ACDF, and four instances of adjacent segment disease. In patients initially treated with multilevel ACDF, revisions occurred most commonly on the caudal level (48% of revised levels), followed by the cranial (43%), and least often in the middle level (9%). Conclusions: This chart review of perioperative and safety outcomes provides evidence in support of tissue-sparing PCF with facet instrumentation as a treatment for symptomatic pseudarthrosis after ACDF. The most common locations requiring revision were the caudal and cranial levels. Operative duration and estimated blood loss were favorable when compared to open alternatives. There were no instances of postoperative wound infection, and the majority of patients were discharged the day following surgery.

Clinical Usefulness of the Active Fixation Quadripolar Left Ventricular Lead Compared With the Passive Fixation Quadripolar Lead in Cardiac Resynchronization Therapy.

BACKGROUND: This study compared the stability of the Medtronic Attain Stability Quad (ASQ), a novel quadripolar active fixation left ventricular (LV) lead with a side helix, to that of conventional quadripolar leads with passive fixation (non-ASQ) and evaluated their LV lead performance.Methods and Results: In all, 183 consecutive patients (69 ASQ, 114 non-ASQ) who underwent cardiac resynchronization therapy (CRT) between January 2018 and June 2021 were enrolled. Complications, including elevated pacing capture threshold (PCT) levels, phrenic nerve stimulation (PNS), and LV lead dislodgement, were analyzed during the postimplantation period until the first outpatient visit after discharge. The frequency of LV lead-related complications was significantly lower in the ASQ than non-ASQ group (14% vs. 30%, respectively; P=0.019). Specifically, LV lead dislodgement occurred only in the non-ASQ group, and elevated PCT levels were significantly lower in the ASQ group (7% vs. 23%; P=0.007). Kaplan-Meier analysis confirmed a significantly lower incidence of LV lead-related complications in the ASQ group (log-rank P=0.005). Cox multivariable regression analysis showed a significant reduction in lead-related complications associated with ASQ (hazard ratio 0.44; 95% confidence interval 0.23-0.83; P=0.011). CONCLUSIONS: The ASQ group exhibited fewer LV lead-related complications requiring reintervention and setting changes than the non-ASQ group. Thus, the ASQ may be a favorable choice for CRT device implantation.

[Transscleral fixation of intraocular lens in the treatment of lens subluxation in children]. / Transskleral'naya fiksatsiya intraokulyarnoi linzy v lechenii sublyuksatsii khrustalika u detei.

Congenital subluxation of the lens as a complication of Marfan syndrome, Weill-Marchesani syndrome, microspherophakia, etc. leads to the development of amblyopia and requires timely surgical treatment with removal of the subluxated lens and implantation of an artificial intraocular lens (IOL). IOL implantation in children with pathology of the ligamentous apparatus of the lens remains an urgent problem of ophthalmic surgery due to the lack of a consensus regarding the IOL fixation method among practitioners. PURPOSE: This study evaluated the effectiveness and safety of IOL implantation with transscleral fixation using the knotless Z-suture technique in pediatric patients with congenital lens subluxation. MATERIAL AND METHODS: The study included 24 children (36 eyes) with grade III congenital subluxation of the lens who underwent phacoaspiration of the subluxated lens with IOL implantation with transscleral fixation using the knotless Z-suture performed in the Kazakh Research Institute of Eye Diseases in Almaty in the period from 2017 to 2021. The average observation period was 31.7±11.3 months (2.0 to 4.5 years). The stability of the IOL position, the state of the intrascleral sutures, visual acuity after surgery, the presence and severity of complications in the long-term period were evaluated. RESULTS: All patients (100%) had a significant improvement in visual acuity after surgery. No intraoperative complications were registered in any of the cases. Postoperative complications were noted in 8.3% of cases (n=3). The final functional outcome of surgical treatment depended on the presence of concomitant pathology, the main cause of low vision was the development of refractive amblyopia due to refractive errors. CONCLUSIONS: The presented technique of transscleral fixation of IOL has proven to be reliable, which is especially important for pediatric patients considering their high physical activity and expected lifespan.

Imidazolium and Pyridinium-based Ionic Porous Organic Polymers: Advances in Transformative Solutions for Oxoanion Sequestration and Non-redox CO2 Fixation.

The rapid pace of industrialization has led to a multitude of detrimental environmental consequences, including water pollution and global warming. Consequently, there is an urgent need to devise appropriate materials to address these challenges. Ionic porous organic polymers (iPOPs) have emerged as promising materials for oxoanion sequestration and non-redox CO2 fixation. Notably, iPOPs offer hydrothermal stability, structural tunability, a charged framework, and readily available nucleophilic counteranions. This review explores the significance of pores and charged functionalities alongside design strategies outlined in existing literature, mainly focusing on the incorporation of pyridinium and imidazolium units into nitrogen-rich iPOPs for oxoanion sequestration and non-redox CO2 fixation. The present review also addresses the current challenges and future prospects, delineating the design and development of innovative iPOPs for water treatment and heterogeneous catalysis.

Nitrogen-fixing bacteria boost floral attractiveness in a tropical legume species during nutrient limitation.

PREMISE: Legumes establish mutualistic interactions with pollinators and nitrogen (N)-fixing bacteria that are critical for plant reproduction and ecosystem functioning. However, we know little about how N-fixing bacteria and soil nutrient availability affect plant attractiveness to pollinators. METHODS: In a two-factorial greenhouse experiment to assess the impact of N-fixing bacteria and soil types on floral traits and attractiveness to pollinators in Chamaecrista latistipula (Fabaceae), plants were inoculated with N-fixing bacteria (NF+) or not (NF-) and grown in N-rich organic soil (+N organic soil) or N-poor sand soil (-N sand soil). We counted buds and flowers and measured plant size during the experiment. We also measured leaf, petal, and anther reflectance with a spectrophotometer and analyzed reflectance curves. Using the bee hexagon model, we estimated chromatic contrasts, a crucial visual cues for attracting bees that are nearby and more distant. RESULTS: NF+ plants in -N sand soil had a high floral display and color contrasts. On the other hand, NF- plants and/or plants in +N organic soil had severely reduced floral display and color contrasts, decreasing floral attractiveness to bee pollinators. CONCLUSIONS: Our findings indicate that the N-fixing bacteria positively impact pollination, particularly when nutrients are limited. This study provides insights into the dynamics of plant-pollinator interactions and underscores the significant influence of root symbionts on key floral traits within tropical ecosystems. These results contribute to understanding the mechanisms governing mutualisms and their consequences for plant fitness and ecological dynamics.

Navigating Visual Challenges: How Parkinson's Disease Alters Cognitive Priorities in Visual Search.

OBJECTIVE: Parkinson's disease (PD) hampers visual search tasks such as reading, driving, and navigation. We examined expectations from past experiences, guiding cognition and contextual priors, on visual search in PD. METHODS: We compared eye movements as PD and healthy participants searched for a hidden object (target) in cluttered real-world scenes. RESULTS: PD participants prolonged fixation on high-probability (high-prior) locations for the target, consistent across expected and unexpected scenario. Such emphasis on contextual visual priors, evidenced by high fixation duration on high-probability areas, was beneficial when the target was at the expected location but presented challenges when the target was situated in an unlikely place. CONCLUSION: This study contributes to understanding how PD impacts visual search behavior and cognitive processing. The findings indicate that PD alters attention allocation and visual processing by affecting the utilization of contextual visual priors. It provides insights for potential interventions targeting visuo-cognitive deficits in PD patients. Published 2024. This article is a U.S. Government work and is in the public domain in the USA.

Response of N, P, and metal ions in deep soil layers to long-term cultivation of rubber and rubber-based agroforestry systems.

The growing demand for natural rubber products has driven the expansion of rubber plantations in recent decades. While much attention has been given to studying the long-term effects of rubber and rubber-based agroforestry systems on surface soil properties, there has been a tendency to overlook changes in soil properties in deeper layers. Our study addresses this gap by examining alterations in nitrogen (N), phosphorus (P), and metal ion levels in deep soil layers resulting from the prolonged cultivation of rubber and rubber-based agroforestry systems. We found notable shifts in soil NH4+ and NO3- concentrations within the 0-30 cm soil layer across different-aged rubber and rubber-based agroforestry systems. Particularly in mature systems, NO3- and available P levels were close to zero below 30 cm soil depth. Introducing Flemingia macrophylla into young rubber plantations increased soil NH4+ and NO3- in the 0-90 cm soil layer and available P in the 0-10 cm soil layer. Over the long term, cultivation of rubber plantations increased the depletion of total P in the 0-50 cm soil layer, available iron (Fe) and manganese (Mn) in the 30-90 cm soil layer, available copper (Cu) and zinc (Zn) in the 0-90 cm soil layer, accompanied by a decrease in soil pH and increase in exchangeable aluminum (Al) in the 0-90 cm soil layer. Notably, soil exchangeable Al levels exceeding 2.0 cmol kg-1 appeared to induce aluminum toxicity. Furthermore, soil pH below 5.2 triggered a sharp release of exchangeable Al within the 0-90 cm soil layer of rubber plantations, with soil available P nearing zero when exchangeable Al levels assed 7.3 cmol kg-1. Our findings underscore the profound impact of long-term rubber plantation cultivation on surface and deep soil properties. Addressing soil degradation in these deep soil layers poses significant challenges for future soil restoration efforts.

Nitrogen inhibition of nitrogenase activity involves the modulation of cytosolic invertase in soybean nodule.

Legume symbiotic nitrogen fixation (SNF) is suppressed by inorganic N in the soil. High N inhibition of nitrogenase activity is associated with the deprivation of carbon allocation and metabolism in nodules. However, the underlying molecular mechanisms remain unclear. Here, we identify GmCIN1 which encodes a cytosolic invertase, as a gateway for the N-tuning of sucrose utilization in nodules. GmCIN1 is enriched in mature soybean nodules and its expression is regulated by nitrogen status. The knockout of GmCIN1 using genome editing partially mimicks the inhibitory effects of N on nitrogenase activity and sugar content and the impact of high N on nodule transcriptomes. This indicates that GmCIN1 partially mediates the high N inhibition of nodule activity. Moreover, ChIP-qPCR and EMSA reveal that SNAP1/2 transcription factors directly bind to the GmCIN1 promoter. In addition, SNAP1/2 may be involved in the repression of GmCIN1 expression in mature nodules at high N concentrations. Our findings provide insights into the involvement of the transcriptional tuning of C metabolism genes by N-signaling modulators in the N-induced inhibition of nitrogenase activity.

Alternate levels versus all levels mini-plate fixation in C3-6 cervical laminoplasty: a retrospective comparative study.

OBJECTIVE: The purpose of this study is to compare radiological and clinical outcomes between alternate levels (C4 and C6) and all levels mini-plate fixation in C3-6 unilateral open-door laminoplasty. METHODS: Ninety-six patients who underwent C3-6 unilateral open-door laminoplasty with alternate levels mini-plate fixation (54 patients in group A) or all levels mini-plate fixation (42 patients in group B) between September 2014 and September 2019 were reviewed in this study. Radiologic and clinical outcomes were assessed. Clinical results included Visual Analogue Scale (VAS) of axial neck pain and Japanese Orthopedic Association (JOA) score. Radiographic results included cervical range of motion (ROM), cervical curvature index (CCI), and the spinal canal expansive parameters including open angle, anteroposterior diameter (APD), and Pavlov`s ratio. RESULTS: There was no significant difference in VAS, JOA score, ROM, and CCI between two groups. There was no significant difference in canal expansion postoperatively between two groups. However, open angle, APD, and Pavlov`s ratio in group A decreased significantly during the follow-up. In group B, APD, Pavlov`s ratio, and open angle were maintained until the final follow-up. There was no hardware failure or lamina reclosure occurred in both groups during the follow-up. The mean cost of group B was higher than that of group A. CONCLUSIONS: Despite the differences in the maintenance of canal expansion, alternate levels mini-plate fixation can achieve similar clinical outcomes as all levels mini-plate fixation in C3-6 unilateral open-door laminoplasty. As evidenced in this study, we believe C3-6 laminoplasty with alternate levels (C4 and C6) mini-plate fixation is an economical, effective, and safe treatment method.

Trends in Cemented Fixation in Hemiarthroplasty for Hip Fractures in Canada.

Bacground: The use of cemented fixation is widely recommended in hip arthroplasty for hip fractures, although it is not used universally. Methods: We describe the trends in cementing prevalence in hemiarthroplasty for hip fractures in Canada for patients ≥55 years old between April 2017 and March 2022. Results: The national prevalence of cemented fixation increased from 43% in 2017/18 to 58% in 2021/22, but there was a large variety of both the baseline prevalence and the trends across the country and between individual hospitals. The proportion of surgeons only performing cementless fixation fell from 30% to 21% between 2018/19 and 2021/22. Conclusions: As cemented fixation is now universally recommended, more coordination is needed to track these trends and to help drive implementation of this evidence-based practice across Canada.

An optimized workflow for transcriptomic analysis from archival paraformaldehyde-fixed retinal tissues collected by laser capture microdissection.

RNA sequencing (RNA-seq) coupled with laser capture microdissection (LCM) is a powerful tool for transcriptomic analysis in unfixed fresh-frozen tissues. Fixation of ocular tissues for immunohistochemistry commonly involves the use of paraformaldehyde (PFA) followed by embedding in Optimal Cutting Temperature (OCT) medium for long-term cryopreservation. However, the quality of RNA derived from such archival PFA-fixed/OCT-embedded samples is often compromised, limiting its suitability for transcriptomic studies. In this study, we aimed to develop a methodology to extract high-quality RNA from PFA-fixed canine eyes by utilizing LCM to isolate retinal tissue. We demonstrate the efficacy of an optimized LCM and RNA purification protocol for transcriptomic profiling of PFA-fixed retinal specimens. We compared four pairs of canine retinal tissues, where one eye was subjected to PFA-fixation prior to OCT embedding, while the contralateral eye was embedded fresh frozen (FF) in OCT without fixation. Since the RNA obtained from PFA-fixed retinas were contaminated with genomic DNA, we employed two rounds of DNase I treatment to obtain RNA suitable for RNA-seq. Notably, the quality of sequencing reads and gene sets identified from both PFA-fixed and FF tissues were nearly identical. In summary, our study introduces an optimized workflow for transcriptomic profiling from PFA-fixed archival retina. This refined methodology paves the way for improved transcriptomic analysis of preserved ocular tissue, bridging the gap between optimal sample preservation and high-quality RNA data acquisition.

Sulfate-reducing consortium HQ23 stabilizes metal(loid)s and activates biological N-fixation in mixed heavy metal-contaminated soil.

Sulfate-reducing bacteria (SRB) are used in the remediation of mine pollution; however, the mechanism of stabilizing multiple heavy metal(loid)s by the SRB consortium under low oxygen conditions needs further study. Indigenous microflora were extracted from non-ferrous metal-contaminated soil co-inoculated with enriched SRB consortium and assembled as the HQ23 consortium. The presence of Desulfovibrio (SRB) in HQ23 was confirmed by 16S rRNA sequencing and qPCR. The effects of culture media, dissolved oxygen (DO), SO42¯, and pH on the HQ23 growth rate, and the SO42¯-reducing activity were examined. Data indicates that the HQ23 sustained SRB function under low DO conditions (3.67 ± 0.1 mg/L), but the SRB activity was inhibited at high DO content (5.75 ± 0.39 mg/L). The HQ23 can grow from pH 5 to pH 9 and can decrease mobile or bioavailable Cr, Cu, and Zn concentrations in contaminated soil samples. FTIR revealed that Cu and Cr adsorbed to similar binding sites on bacteria, likely decreasing bacterial Cu toxicity. Increased abundances of DSV (marker for Desulfovibrio) and nifH (N-fixation) genes were observed, as well as an accumulation of nitrate-N content in soils suggesting that HQ23 stimulates the biological N-fixation in soils. This study strongly supports the future application of SRB for the bioremediation of heavy metal-polluted sites.

Biomechanical analysis of the tandem spinal external fixation in a multiple-level noncontiguous lumbar fractures model: a finite element analysis.

Objective: This study aimed to investigate the biomechanical characteristics of the tandem spinal external fixation (TSEF) for treating multilevel noncontiguous spinal fracture (MNSF) using finite element analysis and provide a theoretical basis for clinical application. Methods: We constructed two models of L2 and L4 vertebral fractures that were fixed with the TSEF and the long-segment spinal inner fixation (LSIF). The range of motion (ROM), maximum stresses at L2 and L4 vertebrae, the screws and rods, and the intervertebral discs of the two models were recorded under load control. Subsequently, the required torque, the maximum stress at L2 and L4 vertebrae, the screws and rods, and the intervertebral discs were analyzed under displacement control. Results: Under load control, the TSEF model reserved more ROM than the LSIF model. The maximum stresses of screws in the TSEF model were increased, while the maximum stresses of rods were reduced compared to the LSIF model. Moreover, the maximum stresses of L2 and L4 vertebrae and discs in the TSEF model were increased compared to the LSIF model. Under displacement control, the TSEF model required fewer moments (N·mm) than the LSIF model. Compared to the LSIF model, the maximum stresses of screws and rods in the TSEF model have decreased; the maximum stresses at L2 and L4 in the TSEF model were increased. In the flexion condition, the maximum stresses of discs in the TSEF model were less than the LSIF model, while the maximum stresses of discs in the TSEF model were higher in the extension condition. Conclusion: Compared to LSIF, the TSEF has a better stress distribution with higher overall mobility. Theoretically, it reduces the stress concentration of the connecting rods and the stress shielding of the fractured vertebral bodies.

Stability before and after percutaneous anterior medullary fixation of lateral compression 1 and 2 pelvic ring disruptions: Should surgeons prioritize the anterior ring?

PURPOSE: Surgical intervention for lateral compression (LC) 1 and 2 pelvic ring fractures is controversial. Posterior ring stabilization remains the most common mode of initial fixation. However, greater mechanical instability is observed in the anterior component of LC pelvic fractures. This study tested whether reduction and percutaneous superior ramus fixation will decrease the instability of LC pelvic fractures on intraoperative fluoroscopic imaging. METHODS: All adult patients (≥ 18 years) presenting with either a Young-Burgess LC1 or LC2 pelvic ring disruption treated operatively with percutaneous anterior followed by posterior fixation by a single surgeon from July 2021 to June 2023 were retrospectively reviewed. Displacement of the anterior ring to intraoperative manual internal rotation stress examination under fluoroscopy was compared before and after anterior pelvic ring reduction and fixation and prior to posterior pelvic ring fixation. Pre- and post-operative visual analog scores (VAS) for pain were also compared. RESULTS: Twenty-one patients with a mean age of 48.7 years were included. Fifteen patients (71.4%) presented with an LC1, and six (28.6%) with an LC2 injury patterns. Anterior pelvic fixation alone provided 7.5mm reduction in mean displacement of the anterior pelvic ring (pre-operative = 9.2 mm vs. post-operative = 1.6 mm, p < 0.001). VAS significantly decreased from 7.2 one-day pre-operatively to 2.2 twenty-four h post-operatively (p < 0.001). CONCLUSIONS: Reduction and fixation of the anterior pelvic ring prior to posterior fixation for LC1 and LC2 pelvic ring disruptions substantially improves mechanical stability on intraoperative stress examination. Combination of percutaneous anterior and posterior fixation significantly decreased VAS above the MCID 24 h after stabilization.

Demineralized Frozen-dried Allogeneic Bone Blocks with Suture Fixation Technique for reconstruction of maxillary alveolar bone deficiency: A Case Series.

PURPOSE: This study aims to evaluate the clinical outcomes of using demineralized freeze-dried allogeneic bone blocks (DFDABB) combined with the periosteal vertical mattress suture (PVMS) technique for the reconstruction of severe horizontal alveolar bone deficiencies in the maxilla. METHOD: In continuous horizontal maxillary defects cases, bone augmentation was performed using DFDABB and deproteinized bovine bone matrix (DBBM) filling the interstice. Subsequently, a resorbable collagen membrane was carefully placed over the graft surface, and both the membrane and bone graft were firmly secured using the periosteal vertical mattress suture technique (PVMS). Linear changes were assessed through superimposed cone-beam computed tomography (CBCT) scans obtained before the operation and after a healing period of 6-10 months. RESULTS: A total of 7 female patients with ten bone blocks and 13 implants were included in this study. One of the wounds was slightly ruptured postoperatively without infection, and all implants showed successful osseointegration. The average alveolar ridge width at a point 5 mm below the crest was 4.52 ± 2.03 mm before bone graft and 9.79 ± 1.57 mm after implantation, with an average increase of 5.26 ± 1.97 mm. Similarly, at a point 10 mm below the crest, the pre-graft alveolar ridge width measured 7.23 ± 3.60 mm, and post-implantation, it expanded to 11.81 ± 2.90 mm, showing an average gain of 4.58 ± 2.01 mm. CONCLUSION: This case series demonstrates the successful application of DFDABB combined with the PVMS technique to achieve adequate bone width for implantation at severe continuous horizontal bone deficiency of the maxilla. DFDABB with the PVMS technique resulted in superior horizontal bone gain during maxillary bone augmentation with horizontal continuity deficiency. However, further studies are necessary to validate these findings.

Evaluating three internal fixation techniques for Pauwels III femoral neck fractures via finite element analysis.

The selection of implants for fixing unstable femoral neck fractures (FNF) remains contentious. This study employs finite element analysis to examine the biomechanics of treating Pauwels type III femoral neck fractures using cannulated compression screws (3CS), biplane double-supported screw fixation (BDSF), and the femoral neck system (FNS). A three-dimensional model of the proximal femur was developed using computed tomography scans. Fracture models of the femoral neck were created with 3CS, BDSF, and FNS fixations. Von Mises stress on the proximal femur, fracture ends, internal fixators, and model displacements were assessed and compared across the three fixation methods (3CS, BDSF, and FNS) during the heel strike of normal walking. The maximum Von Mises stress in the proximal fragment was significantly higher with 3CS fixation compared to BDSF and FNS fixations (120.45 MPa vs. 82.44 MPa and 84.54 MPa, respectively). Regarding Von Mises stress distribution at the fracture ends, the highest stress in the 3CS group was 57.32 MPa, while BDSF and FNS groups showed 51.39 MPa and 49.23 MPa, respectively. Concerning implant stress, the FNS model exhibited greater Von Mises stress compared to the 3CS and BDSF models (236.67 MPa vs. 134.86 MPa and 140.69 MPa, respectively). Moreover, BDSF displayed slightly lower total displacement than 3CS fixation (7.19 mm vs. 7.66 mm), but slightly higher displacement than FNS (7.19 mm vs. 7.03 mm). This study concludes that BDSF outperforms 3CS fixation in terms of biomechanical efficacy and demonstrates similar performance to the FNS approach. As a result, BDSF stands as a dependable alternative for treating Pauwels type III femoral neck fractures.