Feasibility of C2 Lamina Screw Placement in a New Zealand Cohort: Computed Tomography Analysis According to Ethnicity and Gender

BACKGROUND

Previous analyses have suggested variations in cervical spine canal morphology according to ethnicity, possibly in part due to variations in the posterior elements. The potential for these variations to affect the placement of instrumentation is uncertain. The aim of this study was to report on the feasibility of C2 lamina screw insertion in a New Zealand cohort including analysis of Māori, the indigenous people of New Zealand.

METHODS

A trauma computed tomography database was accessed to identify suitable images. On axial images, where the isthmus was at its widest, the outer diameter (OD) and inner diameter (ID) of the lamina were measured. Screw length was measured from a proposed entry point to the contralateral junction of the lamina and lateral mass. The spinolaminar angle was measured as the angle subtended by the screw trajectory and midsagittal plane. A 5.5-mm OD was accepted as a threshold for the feasibility of lamina screw placement.

RESULTS

One hundred eighty-seven images were assessed: 115 New Zealand European and 72 Māori. The mean age of the cohort was 41.9 years (SD 19.6), and most patients (64%) were men. For the entire cohort, mean OD was 6.6 and 6.8 mm on the right and left, respectively; the mean inner diameter was 3.5 and 3.8 mm; mean screw length was 31.5 and 31.5 mm; and mean spinolaminar angle was 46.0° and 46.1°. C2 lamina screw placement was feasible in a majority of patients. Considering only Māori patients, placement was feasible in 96% of right and 94% of left laminae in men but 72% of right and 72% of left laminae in women.

CONCLUSIONS

In a majority of patients, C2 lamina screw placement is feasible. However, advanced imaging must be carefully assessed preoperatively because data suggest that Māori women may not necessarily have optimal anatomy.Clinical RelevanceCare needs to be taken when assessing and planning surgery inpatients of different ethnicities because variations may exist in the morphology of the posterior elements of C2, leading to variation in optimal fixation strategy.Level of Evidence3.

The effect of C2 screw type on perioperative outcomes and long-term stability after C2-T2 posterior cervical decompression and fusion

PURPOSE

To determine if C2 pedicle versus pars screw type predicts change in fusion status, C2 screw loosening, cervical alignment, and patient-reported outcomes measures (PROMs) after C2-T2 posterior cervical decompression and fusion (PDCF).

METHODS

All adult patients who underwent C2-T2 PCDF for myelopathy or myeloradiculopathy between 2013-2020 were retrospectively identified. Patients were dichotomized by C2 screw type into bilateral C2 pedicle and bilateral C2 pars screw groups. Preoperative and short- and long-term postoperative radiographic outcomes and PROMs were collected. Univariate and multivariate analysis compared patient factors, fusion status, radiographic measures, and PROMs across groups.

RESULTS

A total of 159 patients met the inclusion/exclusion criteria (76 bilateral pedicle screws, 83 bilateral pars screws). Patients in the C2 pars relative to C2 pedicle screw group were on average more likely to have bone morphogenic protein (p = 0.001) and four-millimeter diameter rods utilized intraoperatively (p = 0.033). There were no significant differences in total construct and C2-3 fusion rate, C2 screw loosening, or complication and revision rates between C2 screw groups in univariate and regression analysis. Changes in C2 tilt, C2-3 segmental lordosis, C0-2 Cobb angle, proximal junctional kyphosis, atlanto-dens interval, C1 lamina-occiput distance, C2 sagittal vertical axis, C2-7 lordosis, and PROMs at all follow-up intervals did not vary significantly by C2 screw type.

CONCLUSION

There were no significant differences in fusion status, hardware complications, and radiographic and clinical outcomes based on C2 screw type following C2-T2 PCDF. Accordingly, intraoperative usage criteria can be flexible based on patient vertebral artery positioning and surgeon comfort level.

Effect of High-Riding Vertebral Artery on the Accuracy and Safety of C2 Pedicle Screw Placement in Basilar Invagination and Related Risk Factors

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate the effect of HRVA on the intrapedicular accuracy of C2PS placement through the freehand method in patients with BI and analyse the possible risk factors for C2PS malpositioning.

METHOD

A total of 91 consecutive patients with BI who received 174 unilateral C2PS placements through the freehand method were retrospectively included. The unilateral pedicles were assigned to the HRVA and non-HRVA groups. The primary outcome was the intrapedicular accuracy of C2PS placement in accordance with the Gertzbein-Robbins scale. Moreover, the risk factors that possibly affected intrapedicular accuracy were assessed.

RESULTS

The rate of intrapedicular accuracy in C2PS placement in patients with BI was 23.6%. Results showed that the non-HRVA group had remarkably higher rates of optimal and clinically acceptable C2PS placement than the HRVA group. Nevertheless, the HRVA group exhibited similar results for grade B classification as the non-HRVA group. Moreover, in the HRVA and non-HRVA groups, the most common direction of screw deviations was the lateral direction. Furthermore, the multivariate analyses showed that the obliquity of the lateral atlantoaxial joint in the sagittal plane ≥15°, and that in the coronal plane ≥ 20°, isthmus height < 4.3 mm, and distance from the skin to the spinous process ≥ 2.8 cm independently contributed to a high rate of screw malpositioning in BI patients.

CONCLUSION

The presence of HRVA in BI patients contributed to the high rate of malpositioning in C2PS placement via the freehand method. However, the rates of intrapedicular accuracy in patients with BI with and without HRVA were considerably low.

Genetic Diversity of the Human Adenovirus C Isolated from Hospitalized Children in Russia (2019-2022)

The human adenovirus (HAdV) is a common pathogen in children that can cause acute respiratory virus infection (ARVI). However, the molecular epidemiological and clinical information relating to HAdV among hospitalized children with ARVI is rarely reported in Russia. A 4-year longitudinal (2019-2022) study among hospitalized children (0-17 years old) with ARVI in Novosibirsk, Russia, was conducted to evaluate the epidemiological and molecular characteristics of HAdV. Statistically significant differences in the detection rates of epidemiological and virological data of all positive viral detections of HAdV were analyzed using a two-tailed Chi-square test. The incidence of HAdV and other respiratory viruses such as human influenza A and B viruses, respiratory syncytial virus, coronavirus, parainfluenza virus, metapneumovirus, rhinovirus, bocavirus, and SARS-CoV-2 was investigated among 3190 hospitalized children using real-time polymerase chain reaction. At least one of these respiratory viruses was detected in 74.4% of hospitalized cases, among which HAdV accounted for 4%. A total of 1.3% co-infections with HAdV were also registered. We obtained full-genome sequences of 12 HAdVs, which were isolated in cell cultures. Genetic analysis revealed the circulation of adenovirus of genotypes C1, C2, C5, C89, and 108 among hospitalized children in the period from 2019-2022.

A cost-consequence model of using the 21-gene assay to identify patients with early-stage node-positive breast cancer who benefit from adjuvant chemotherapy in the Netherlands

BACKGROUND

Patients with early-stage hormone receptor positive, human epidermal growth factor receptor-2 (HER2) negative invasive breast cancer with 1-3 positive lymph nodes (N1) often undergo surgical excisions followed by adjuvant chemotherapy (ACT). Many patients have no benefit from ACT and receive unnecessary, costly treatment often associated with short- and long-term adverse events (AEs). Gene expression profiling (GEP) assays, such as the 21-gene assay (i.e. the Oncotype DX assay), can identify patients at higher risk for recurrence who may benefit from ACT. However, the budgetary consequence of using the Oncotype DX assay versus no GEP testing in the Netherlands is unknown. Our study therefore assessed it using a cost-consequence model.

METHODS

A validated model was used to create the N1 model. The model compared the costs and consequences of using the Oncotype DX assay versus no GEP testing and MammaPrint, and subsequent ACT use with corresponding costs for chemotherapy, treatment of AEs, productivity losses, GEP testing, and treatment of recurrences, according to the Oncotype DX results. The model time horizon was 5 years.

RESULTS

Costs for the total population amounted to €8.0 million (M), €16.2 M, and €9.5 M, and cost per patient amounted to €13,540, €27,455, and €16,154 for using the Oncotype DX assay, no GEP testing, and MammaPrint, respectively. Total cost savings of using the Oncotype DX assay amounted to €8.2 M versus no GEP testing and €1.5 M versus MammaPrint. Using the Oncotype DX assay would result in fewer patients receiving ACT and thus fewer AEs, sick days, and hospitalizations, leading to overall cost savings compared with no GEP testing and MammaPrint.

CONCLUSIONS

Implementing Oncotype DX testing in this population can prevent unnecessary overtreatment, reducing clinical and economic burden on the patient and Dutch healthcare system.

The demographic, clinical, and management differences between traumatic dens fracture patients with and without simultaneous atlas fractures

Introduction

Atlas fractures often accompany traumatic dens fractures, but existing literature on the management of simultaneous atlantoaxial fractures is limited.

Methods

We examined all patients with traumatic dens fractures at our institution between 2008 and 2018. We used multivariable logistic regression and ordinal logistic regression to identify factors independently associated with presentation with a simultaneous atlas fracture, as well myelopathy severity, fracture nonunion, and selection for surgery.

Results

Two hundred and eighty-two patients with traumatic dens fractures without subaxial fractures were identified, including 65 (22.8%) with simultaneous atlas fractures. The distribution of injury mechanisms differed between groups (χ2 P = 0.0360). On multivariable logistic regression, dens nonunion was positively associated with type II fractures (odds ratio [OR] = 2.00, P = 0.038) and negatively associated with having surgery (OR = 0.52, P = 0.049), but not with having a C1 fracture (P = 0.3673). Worse myelopathy severity on presentation was associated with having a severe injury severity score (OR = 102.3, P < 0.001) and older age (OR = 1.28, P = 0.002), but not with having an atlas fracture (P = 0.2446). Having a simultaneous atlas fracture was associated with older age (OR = 1.29, P = 0.024) and dens fracture angulation (OR = 2.62, P = 0.004). Among patients who underwent surgery, C1/C2 posterior fusion was the most common procedure, and having a simultaneous atlas fracture was associated with selection for occipitocervical fusion (OCF) (OR = 14.35, P = 0.010).

Conclusions

Among patients with traumatic dens, patients who have simultaneous atlas fractures are a distinct subpopulation with respect to age, mechanism of injury, fracture morphology, and management. Traumatic dens fractures with simultaneous atlas fractures are independently associated with selection for OCF rather than posterior cervical fusion alone.

Atlas fractures with and without simultaneous dens fractures differ with respect to clinical, demographic, and management characteristics

Background

Patients with simultaneous fractures of the atlas and dens have traditionally been managed according to the dens fracture's morphology, but data supporting this practice are limited.

Methods

We retrospectively examined all patients with traumatic atlas fractures at our institution between 2008 and 2016. We used multivariable regression and propensity score matching to compare the presentation, management, and outcomes of patients with isolated atlas fractures to patients with simultaneous atlas-dens fractures.

Results

Ninety-nine patients were identified. Patients with isolated atlas fractures were younger (61 ± 22 vs. 77 ± 14, P = 0.0003), had lower median Charlson Comorbidity Index (3 vs. 5, P = 0.0005), had better presenting Nurick myelopathy scores (0 vs. 3, P < 0.0001), and had different mechanisms of injury (P = 0.0011). Multivariable regression showed that having a simultaneous atlas-dens fracture was independently associated with older age (odds ratio [OR] =1.59 [1.22, 2.07], P = 0.001), worse presenting myelopathy (OR = 3.10 [2.04, 4.16], P < 0.001), and selection for surgery (OR = 4.91 [1.10, 21.97], P = 0.037). Propensity score matching yielded balanced populations (Rubin's B = 23.3, Rubin's R = 1.96) and showed that the risk of atlas fracture nonunion was no different among isolated atlas fractures compared to simultaneous atlas-dens fractures (P = 0.304). Age was the only variable independently associated with atlas fracture nonunion (OR = 2.39 [1.15, 5.00], P = 0.020), having a simultaneous atlas-dens fracture was not significant (P = 0.2829).

Conclusions

Among patients with atlas fractures, simultaneous fractures of the dens occur in older patients and confer an increased risk of myelopathy and requiring surgical stabilization. Controlling for confounders, the risk of atlas fracture nonunion is equivalent for isolated atlas fractures versus simultaneous atlas-dens fractures.

C2 stentoplasty: an alternative to conventional vertebroplasty in the treatment of axis metastatic lesions: a systematic review with meta-analysis and case series

BACKGROUND

Vertebroplasty has been recently described in the literature as a potential treatment for C2 metastatic lesions. Stentoplasty may represent a safest and equally alternative to the latter.

OBJECTIVE

To describe a novel technique, stentoplasty, as an alternative for the treatment of metastatic involvement of C2 and to assess its efficacy and safety. To systematically evaluate the pertinent literature regarding the clinical outcomes and complications of C2 vertebroplasty in patients with metastatic disease.

METHODS

A systematic review of C2 vertebroplasty, in the English language medical literature was conducted for the needs of this study. Additionally, a cohort of five patients, presenting with cervical instability (SINS > 6) and/or severe pain (VAS > 6) from metastatic involvement of C2 and treated with stentoplasty in our department is presented. Outcomes evaluated include, pain control, stability, and complications.

RESULTS

Our systematic review yielded 8 studies that met the inclusion criteria, incorporating 73 patients that underwent C2 vertebroplasty for metastatic disease. There was a reduction in VAS scores following surgery from 7.6 to 2.1. Eleven patients had complications (15%), 3 (4%) required additional stabilization and decompression, 6 (8.2%) had odynophagia and the incidence of cement leak was 31.5% (23/73). With regard to our cohort, all 5 patients presented with severe neck pain (average VAS 6.2 (2-10)) with or without instability (average SINS 10 (6-14)) and underwent C2 stentoplasty. Mean duration of the procedures was 90 min (61-145) and 2.6 mls (2-3) of cement was injected. Postoperatively VAS improved from 6.2 to 1.6 (P = 0.033). No cement leak or other complications were recorded.

CONCLUSION

A systematic review of the literature demonstrated that C2 vertebroplasty can offer significant pain improvement with a low complication rate. At the same time, this is the first study to describe stentoplasty in a small cohort of patients, as an alternative for the treatment of C2 metastatic lesions in selected cases, offering adequate pain control and improving segmental stability with a high safety profile.

The Feasibility of Multiple Fixation Points in C2

STUDY DESIGN

Analysis using three-dimensional simulation software for spinal screw placement and computed tomographic scan images.

PURPOSE

To assess the feasibility of achieving multiple (three or four) screw fixation points in C2 vertebra by using a combination of pedicle and laminar screws.

OVERVIEW OF LITERATURE

Secure C2 fixation using multiple screws is required or beneficial in some unique cases. However, to the best of our knowledge, there have been no reports analyzing the feasibility of multiple screw fixation in C2.

METHODS

We used 1.0-mm interval computed tomographic scan images of 100 patients (50 men and 50 women) and screw trajectory simulation software. The diameter of all screws was set at 3.5 mm, considering its common usage in real surgery. The anatomical feasibility of placing both pedicle and laminar screws on the same side was evaluated. For all feasible sides, the three-dimensional distance between the screw entry points was measured.

RESULTS

In 85% of cases, both pedicle and laminar screws could be placed on both sides, allowing for the insertion of 4 screws. In 11% of cases, 2 screws could be placed on one side, while only 1 screw was feasible on the other side, resulting in the placement of 3 screws. In all 181 sides where both types of screws could be inserted, the distance between their entry points exceeded 16.1 mm, which was sufficient to prevent the collision between the screw heads.

CONCLUSIONS

C2 vertebra can accommodate three (11%) or four (85%) screws in 96% of cases.

Traumatic Dens Fracture Patients Comprise Distinct Subpopulations Distinguished by Differences in Age, Sex, Injury Mechanism and Severity, and Outcome

BACKGROUND

Dens fractures are an increasingly common injury, yet their epidemiology and its implications remain underexamined.

METHODS

We retrospectively analyzed all traumatic dens fracture patients managed at our institution over a 10-year period, examining demographic, clinical, and outcomes data. Patient subsets were compared across these parameters.

RESULTS

Among 303 traumatic dens fracture patients, we observed a bimodal age distribution with a strong goodness of fit centered at age 22.3 ± 5.7 (R = 0.8781) and at 77.7 ± 13.9 (R = 0.9686). A population pyramid demonstrated a bimodal distribution among male patients, but not female patients, which was confirmed with a strong goodness of fit for male patient subpopulations age <35 (R = 0.9791) and age ≥35 (R = 0.8843), but a weaker fit for a second female subpopulation age <35. Both age groups were equally likely to undergo surgery. Patients younger than age 35 were more likely to be male (82.4% vs. 46.9%, odds ratio [OR] = 5.29 [1.54, 17.57], P = 0.0052), have motor vehicle collision as their mechanism of injury (64.7% vs. 14.1%, OR = 11.18 [3.77, 31.77], P < 0.0001), and to have a severe trauma injury severity score (17.6% vs. 2.9%, OR = 7.23 [1.88, 28.88], P = 0.0198). Nevertheless, patients age <35 were less likely to have fracture nonunion at follow (18.2% vs. 53.7%, OR = 0.19 [0.041, 0.76], P = 0.0288).

CONCLUSIONS

The dens fracture patient population comprises 2 subpopulations, distinguished by differences in age, sex, injury mechanism and severity, and outcome, with male dens fracture patients demonstrating a bimodal age distribution. Young, male patients were more likely to have high-energy injury mechanisms leading to severe trauma, yet were less likely to have fracture nonunion at follow-up.

A nanobody-based complement inhibitor targeting complement component 2 reduces hemolysis in a complement humanized mouse model of autoimmune hemolytic anemia

C2 is an attractive therapeutic target for many complement-mediated diseases. We developed Nab1B10, a new anti-C2 nanobody that potently and selectively inhibits both the classical and lectin pathways of complement activation. Mechanistically, Nab1B10 binds to the C2a portion of C2 and inhibits the assembly of C3 convertase C4b2a. Nab1B10 cross-reacts with monkey but not rodent C2 and inhibits classical pathway-mediated hemolysis. Using a new complement humanized mouse model of autoimmune hemolytic anemia (AIHA), we demonstrated that Nab1B10 abolished classical pathway complement activation-mediated hemolysis in vivo. We also developed C2-neutralizing bi- and tetra-valent antibodies based on Nab1B10 and found these antibodies significantly more potent than the other anti-C2 monoclonal antibody that is already in clinical trials. These data suggest that these novel C2-neutralizing nanobodies could be further developed as new therapeutics for many complement-mediated diseases, in which pathogenesis is dependent on the classical and/or lectin pathway of complement activation.

Upper cervical anterior fusion to C2 with temporary infrahyoid muscle detachment: a clinical case series and description of surgical technique

BACKGROUND

Anterior cervical spine surgery to C2 (ACSS-C2) is a challenging procedure that often results in postoperative persistent dysphagia or dyspnea due to injury to the internal branch of the superior laryngeal nerve (iSLN) or the relatively narrow and soft oropharynx. This study aimed to describe the surgical outcomes of our modified approach with temporary infrahyoid muscle detachment during ACSS-C2.

METHODS

Patients who underwent ACSS-C2 at two institutions between June 2015 and January 2022 were prospectively enrolled. Intraoperatively, we performed temporary detachment of the infrahyoid muscle from the hyoid bone to improve laryngeal mobility and accessibility to C2. This procedure also allowed for the easy identification and preservation of the iSLN. We retrospectively investigated the surgery-related complications and outcomes of bony fusion.

RESULTS

Twelve patients were enrolled in this study; five and seven patients underwent single- and multi-level fusion surgery, respectively. Intraoperative preservation of the iSLN and proper visualization of C2 were achieved in all cases. Subsequent decompression and instrumentation were successfully performed. Two older patients (78 and 81 years) who underwent multi-level fusion experienced transient postoperative dysphagia. None of the patients required unplanned reintubation or revision surgery because of instrumentation failure. Solid bony fusion was achieved in all cases.

CONCLUSIONS

Our modified approach with temporary infrahyoid muscle detachment during ACSS-C2 reduces the incidence of postoperative persistent dysphagia and dyspnea. However, in older patients at high risk for postoperative dysphagia, multi-level fusion should be avoided, and alternative procedures should be considered.

Serum Metabolite Biomarkers for Pancreatic Tumors: Neuroendocrine and Pancreatic Ductal Adenocarcinomas-A Preliminary Study

BACKGROUND

Pancreatic cancer is the most common pancreatic solid malignancy with an aggressive clinical course and low survival rate. There are a limited number of reliable prognostic biomarkers and a need to understand the pathogenesis of pancreatic tumors; neuroendocrine (PNET) and pancreatic ductal adenocarcinomas (PDAC) encouraged us to analyze the serum metabolome of pancreatic tumors and disturbances in the metabolism of PDAC and PNET.

METHODS

Using the AbsoluteIDQ^® p180 kit (Biocrates Life Sciences AG, Innsbruck, Austria) with liquid chromatography-mass spectrometry (LC-MS), we identified changes in metabolite profiles and disrupted metabolic pathways serum of NET and PDAC patients.

RESULTS

The concentration of six metabolites showed statistically significant differences between the control group and PDAC patients (p.adj < 0.05). Glutamine (Gln), acetylcarnitine (C2), and citrulline (Cit) presented a lower concentration in the serum of PDAC patients, while phosphatidylcholine aa C32:0 (PC aa C32:0), sphingomyelin C26:1 (SM C26:1), and glutamic acid (Glu) achieved higher concentrations compared to serum samples from healthy individuals. Five of the tested metabolites: C2 (FC = 8.67), and serotonin (FC = 2.68) reached higher concentration values in the PNET serum samples compared to PDAC, while phosphatidylcholine aa C34:1 (PC aa C34:1) (FC = -1.46 (0.68)) had a higher concentration in the PDAC samples. The area under the curves (AUC) of the receiver operating characteristic (ROC) curves presented diagnostic power to discriminate pancreatic tumor patients, which were highest for acylcarnitines: C2 with AUC = 0.93, serotonin with AUC = 0.85, and PC aa C34:1 with AUC = 0.86.

CONCLUSIONS

The observations presented provide better insight into the metabolism of pancreatic tumors, and improve the diagnosis and classification of tumors. Serum-circulating metabolites can be easily monitored without invasive procedures and show the present clinical patients' condition, helping with pharmacological treatment or dietary strategies.

[Advances in surgical strategies for ossification of posterior longitudinal ligament involving the C 2 segment]

Objective

To evaluate the application of surgical strategies for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL) involving the C ₂ segment.

Methods

The literature about the surgery for cervical OPLL involving C ₂ segment was reviewed, and the indications, advantages, and disadvantages of surgery were summarized.

Results

For cervical OPLL involving the C ₂ segments, laminectomy is suitable for patients with OPLL involving multiple segments, often combined with screw fixation, and has the advantages of adequate decompression and restoration of cervical curvature, with the disadvantages of loss of cervical fixed segmental mobility. Canal-expansive laminoplasty is suitable for patients with positive K-line and has the advantages of simple operation and preservation of cervical segmental mobility, and the disadvantages include progression of ossification, axial symptoms, and fracture of the portal axis. Dome-like laminoplasty is suitable for patients without kyphosis/cervical instability and with negative R-line, and can reduce the occurrence of axial symptoms, with the disadvantage of limited decompression. The Shelter technique is suitable for patients with single/double segments and canal encroachment >50% and allows for direct decompression, but is technically demanding and involves risk of dural tear and nerve injury. Double-dome laminoplasty is suitable for patients without kyphosis/cervical instability. Its advantages are the reduction of damage to the cervical semispinal muscles and attachment points and maintenance of cervical curvature, but there is progress in postoperative ossification.

Conclusion

OPLL involving the C ₂ segment is a complex subtype of cervical OPLL, which is mainly treated through posterior surgery. However, the degree of spinal cord floatation is limited, and with the progress of ossification, the long-term effectiveness is poor. More research is needed to address the etiology of OPLL and to establish a systematic treatment strategy for cervical OPLL involving the C ₂ segment.

Geminiviral C2 proteins inhibit active autophagy to facilitate virus infection by impairing the interaction of ATG7 and ATG8

Autophagy is a conserved intracellular degradation process that plays an active role in plant response to virus infections. Here we report that geminiviruses counteract activated autophagy-mediated antiviral defense in plant cells through the C2 proteins they encode. We found that, in Nicotiana benthamiana plants, tomato leaf curl Yunnan virus (TLCYnV) infection upregulated the transcription levels of autophagy-related genes (ATGs). Overexpression of NbATG5, NbATG7, or NbATG8a in N. benthamiana plants decreased TLCYnV accumulation and attenuated viral symptoms. Interestingly, transgenic overexpression of NbATG7 promoted the growth of N. benthamiana plants and enhanced plant resistance to TLCYnV. We further revealed that the C2 protein encoded by TLCYnV directly interacted with the ubiquitin-activating domain of ATG7. This interaction competitively disrupted the ATG7-ATG8 binding in N. benthamiana and Solanum lycopersicum plants, thereby inhibiting autophagy activity. Furthermore, we uncovered that the C2-mediated autophagy inhibition mechanism was conserved in three other geminiviruses. In summary, we discovered a novel counter-defensive strategy employed by geminiviruses that enlists their C2 proteins as disrupters of ATG7-ATG8 interactions to defeat antiviral autophagy.

BCI Applications to Creativity: Review and Future Directions, from little-c to C2

BCI devices are increasingly being used to create interactive interfaces between users and their own psychophysiological signals. Over the years, these systems have seen strong development as they can enable people with limited mobility to make certain decisions to alter their environment. Additionally, their portability and ease of use have allowed a field of research to flourish for the study of cognitive and emotional processes in natural settings. The study of creativity, especially little creativity (little-c), is one example, although the results of this cutting-edge research are often poorly systematized. The purpose of the present paper, therefore, was to conduct a scoping review to describe and systematize the various studies that have been conducted on the application potential of BCI to the field of creativity. Twenty-two papers were selected that collect information on different aspects of creativity, including clinical applications; art experience in settings with high ecological validity; BCI for creative content creation, and participants' engagement. Critical issues and potentialities of this promising area of study are also presented. Implications for future developments towards multi-brain creativity settings and C² are discussed.

Epidemiology of C2 fractures in the United States: A National Electronic Injury Surveillance System database study

Introduction

C2 fractures are one of the most common traumatic injuries of the cervical spine, with high rates of morbidity and mortality. Current literature on the incidence of C2 fractures is limited to populations outside of the United States (US), prior to 2014, or specific age cohorts. The purpose of this study is to report the incidence rate (IR) of C2 fractures and associated patient demographics in the US between 2002 and 2021 using the National Electronic Injury Surveillance System (NEISS) database.

Methods

This study analyzed the NEISS database to identify cases of C2 fractures presenting to US Emergency Departments (EDs) from 2002 to 2021. Annual and overall numbers of fractures, IR, and patient demographics were analyzed. IR is expressed as the number of fractures per 100,000 person-years at risk (PYR). Patients were split into three different age groups for comparison (children and young adults, 0-64 years; older adults, 65-79 years; elderly individuals, 80 + years).

Results

A national estimate of n = 72,764 patients (95% confidence interval [CI] = 54,371-91,156) presented to US EDs with a C2 fracture (IR was 1.17/PYR; 95% CI = 0.87-1.46), and elderly individuals had the highest IR overall (IR = 15.9; P < 0.05). The IR of C2 fractures between 2002 and 2021, reported as average annual percent change (AAPC), increased significantly, regardless of age or sex (AAPC = 10.9; 95% CI = 6.3-15.6; P < 0.0001).

Conclusion

C2 fractures occur at higher rates than previous years, with especially high IR in elderly individuals. Emphasis of public health efforts toward osteoporosis and coordination difficulties in elderly individuals would likely significantly reduce the overall IR of these injuries.

Does Ending a Posterior Construct Proximally at C2 Versus C3 Impact Patient Reported Outcomes in Degenerative Cervical Myelopathy Patients up to 24 months After the Surgery?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The primary objective was to evaluate the impact of the upper instrumented level (UIV) being at C2 vs C3 in posterior cervical construct on patient reported outcomes (PROs) up to 24 months after surgery for cervical degenerative myelopathy (DCM). Secondary objectives were to compare operative time, intra-operative blood loss (IOBL), length of stay (LOS), adverse events (AEs) and re-operation.

METHODOLOGY

Patients who underwent a posterior cervical instrumented fusion (3 and + levels) with a C2 or C3 UIV, with 24 months follow-up were analyzed. PROs (NDI, EQ5D, SF-12 PCS/MCS, NRS arm/neck pain) were compared using ANCOVA. Operative duration, IOBL, AEs, and re-operation were compared. Subgroup analysis was performed on patient presenting with pre-operative malalignment (cervical sagittal vertical axis ≥40 mm and/or T1slope- cervical lordosis >15°).

RESULTS

173 patients were included, of which 41 (24%) had a C2 UIV and 132 (76%) a C3 UIV. There was no statistically significant difference between the groups for the changes in PROs up to 24 months. Subgroup analysis of patients with pre-operative malalignment showed a trend towards greater improvement in the NDI at 12 months with a C2 UIV (P = .054). Operative time, IOBL and peri-operative AEs were more in C2 group (P < .05). There was no significant difference in LOS and re-operation (P > .05).

CONCLUSION

In this observational study, up to 24 months after surgery for posterior cervical fusion in DCM greater than 3 levels, PROs appear to evolve similarly.

Technique of C2 Nerve Root Preservation in the Presence of Anomalous Vertebral Artery in Atlantoaxial Operations

While accessing the C1-C2 joint during posterior atlantoaxial fixation, the C2 nerve root along with its perineural venous plexus remains an obstacle for a panoramic visualization of the entry point of the C1 lateral mass and joint preparation. Therefore, many surgeons frequently advocate its intentional sectioning during this approach, with no related major complications.^1,2 However, this sectioning has at times been associated with symptoms such as hypoesthesia, numbness, dysesthesia, and neuropathic ulcers.³ Thus C2 nerve root preservation during posterior approach for atlantoaxial dislocation (AAD) could potentially avoid such consequences.⁴ Its preservation has been described for AAD cases with relatively normal C1-C2 joint anatomy with no osseovascular abnormalities.² In contrast, attempt at C2 nerve root preservation in patients with congenital AAD harboring bony and vascular anomalies poses a greater challenge owing to a restricted operative space and the potential for perineural venous bleeding during dissection. This is more so for young neurosurgeons in the initial part of their learning curve. Video 1 details the technique of C2 nerve root dissection and preservation in a case of congenital AAD with an anomalous vertebral artery (VA). Computed tomography (CT) of this 30-year-old male patient with spastic quadriparesis showed AAD/basilar invagination with an assimilated C1-arch and right anomalous VA on CT angiography. He underwent C1-C2 joint manipulation and short-segment fixation. At 1-year follow-up, the patient's limb weakness had improved and CT showed good bony fusion. The salient operative steps involve gentle teasing and dissection of perineural soft tissues above and below the nerve root; the key to minimize venous bleeding is to dissect, coagulate, and divide them sequentially. A thorough release of the perineural soft tissues allows adequate nerve root mobilization, which in turn provides clear visualization of the C1-C2 joint space, preventing an undue nerve stretching during the C1-lateral mass screw insertion. The anomalous VA usually lies anterior to the C2 nerve root, and careful imaging evaluation allows its anticipation.³ We do not prefer the easy alternative of C2 nerve root sacrifice because of its inherent complications we noticed in our earlier clinical practice.³.

Healthcare resource utilization and costs of care in the United States for patients with non-alcoholic steatohepatitis

AIMS

This retrospective, observational cohort study aimed to determine the burden of comorbidities, hospitalization, and healthcare costs among patients with non-alcoholic steatohepatitis (NASH) in the United States stratified by fibrosis-4 (FIB-4) or body mass index (BMI).

METHODS

Adults with NASH were identified in the Veradigm Health Insights Electronic Health Record Database and linked Komodo claims data. The index date was the earliest coded NASH diagnosis between 1 January 2016 and 31 December 2020 with valid FIB-4 and ≥6 months of database activity and continuous enrollment pre- and post-index. We excluded patients with viral hepatitis, alcohol-use disorder, or alcoholic liver disease. Patients were stratified by FIB-4: FIB-4 ≤ 0.95, 0.95 < FIB-4 ≤ 2.67, 2.67 < FIB-4 ≤ 4.12, FIB-4 > 4.12) or BMI (BMI <25, 25 ≤ BMI ≤30, BMI > 30). Multivariate analysis was used to assess the relationship of FIB-4 with costs and hospitalizations.

RESULTS

Among 6,743 qualifying patients, index FIB-4 was ≤0.95 for 2,345 patents, 0.95-2.67 for 3,289 patients, 2.67-4.12 for 571 patients, and >4.12 for 538 patients (mean age 55.8 years; 62.9% female). Mean age, comorbidity burden, cardiovascular disease risk, and healthcare utilization increased with increasing FIB-4. Mean ± SD annual costs increased from $16,744±$53,810 to $34,667±$67,691 between the lowest and highest FIB-4 cohorts and were higher among patients with BMI <25 ($24,568±$81,250) than BMI >30 ($21,542±$61,490). A one-unit increase in FIB-4 at index was associated with a 3.4% (95%CI: 1.7%-5.2%) increase in mean total annual cost and an 11.6% (95%CI: 8.0%-15.3%) increased likelihood of hospitalization.

CONCLUSIONS

A higher FIB-4 was associated with increased healthcare costs and risk of hospitalization in adults with NASH; however, even patients with FIB-4 ≤ 0.95 presented a significant burden.

Quantitative fluorescence resonance energy transfer-based immunoassay for activated complement C1s

Objectives

C1s activation is associated with the pathogenesis of various diseases, indicating the potential value of C1s activation detection in clinic. Here we aimed to establish fluorescence resonance energy transfer (FRET)-based immunoassay for the quantitative detection of activated C1s in serum.

Methods

FRET-based fluorogenic peptides, sensitive to the enzymatic activity of activated C1s, were prepared and labeled with the fluorophore ortho-aminobenzoic acid (Abz) and quencher 2,4-dinitrophenyl (Dnp), and then were further selected depending on its Kcat/Km value. C1s in the samples was captured and separated using anti-C1s-conjugated magnetic microbeads. Next, enzymatic activity of activated C1s in samples and standards was examined using fluorescent quenched substrate assays. Limit of detection (LOD), accuracy, precision, and specificity of FRET-based immunoassay were also investigated.

Results

This method presented a linear quantification range for the enzymatic activity of activated C1s up to 10 μmol min^-1 mL^-1 and LOD of 0.096 μmol·min^-1·mL^-1 for serum samples. The recovery of the method was in the range of 90% ~ 110%. All CV values of the intra-analysis and inter-analysis of three levels in samples were less than 10%. The cross-reaction rates with C1r enzyme, MASP1, and MASP2 were less than 0.5%. No significant interferences were found with bilirubin (0.2 mg mL^-1), Chyle (2000 FTU), and haemoglobin (5 mg mL^-1), but anticoagulants (EDTA, citrate and heparin) inhibited the enzymatic ability of activated C1s. Thus, this established method can be used for the determination of active C1s in human serum samples in the concentration interval of 0.096-10.000 μmol min^-1 mL^-1.

Conclusions

One anti-C1s-based FRET immunoassay for activated C1s detection in serum samples were established, and it will be useful to explore the role of C1s activation in the pathogenesis, diagnosis and treatment in complement-related diseases.

Transoral vertebroplasty for the treatment of C2 painful metastatic lesions; evaluation and outcome

OBJECTIVE

A small number of studies supports vertebroplasty at the C2 vertebral body due to the documented technical challenges, the rarity of C2 osteolytic metastatic lesions, and the existence of potentially serious consequences linked to this particular anatomical area. Vertebroplasty, in such a situation, can be performed through a transoral, an anterolateral, or an open approach. All are supported by a limited number of studies with absence of a significant clinical trial assessing the efficacy, safety, and feasibility of vertebroplasty for the C2 vertebral body. We, herein, summarize a single-institution experience on C2 transoral vertebroplasty.

PATIENTS AND METHODS

This is a retrospective analysis of the records of a single tertiary institute hospital and the clinical visits of nine patients with C2 osteolytic metastatic lesions treated by transoral fluoroscopically guided vertebroplasty between May 2016 and May 2021.

RESULTS

The median period of the last clinical follow-up was 23 months (range, 9-60 months). The intraoperative amount of polymethyl methacrylate (PMMA) injected and recorded in the surgical report was 2 mL (1.5-2.5 mL). Postoperative immediate imaging showed that the cement filling percentage in relation to the C2 mass was 70% (40-85%). The PMMA leakage through the needle track and into the paravertebral spaces was observed in only one patient (11.1%), without significant vascular and neurological consequences. Stability was maintained during the follow-up period. The postoperative median pain rating scale (PRS) score was 1 (0-2) immediately after the end of the operation and 0 (0-2) at the last visit. The recorded postoperative Pain Rating Scale (PRS) score was correlated with the cement filling percentage (rs= -0.9, p = 0.0008; Spearman correlation).

CONCLUSION

Transoral vertebroplasty is considered feasible and efficient technique in the treatment of secondary osteolytic lesions in the C2 vertebra. Further long-term and larger comparative randomized studies are required to perform a more comprehensive analysis of this technique.

Ideal entry point and trajectory for C2 pedicle screw placement in basilar invagination patients with high-riding vertebral artery based on 3D computed tomography

BACKGROUND

C2 pedicle screw placement in patients with basilar invagination (BI) is fraught with risks because of a high incidence of anatomical variations and high-riding vertebral artery (HRVA). However, no study can be found in the literature that attempted to identify the ideal entry point and trajectory through the C2 pedicle in BI patients with HRVA.

PURPOSE

To investigate the parameters of ideal entry point and trajectory for C2 pedicle screw placement in BI patients with HRVA and compare them with those in BI patients without HRVA and patients without BI as control. These parameters would serve as a guide to pedicle screw placement.

STUDY DESIGN

A retrospective comparative study.

PATIENT SAMPLE

A total of 396 patients (198 consecutive BI patients and 198 matched patients without BI as control) and 792 unilateral pedicles from April 2017 to October 2021 at two medical centers were included.

OUTCOME MEASURES

The insertion parameters of mediolateral angle, surface distance, cephalad angle, and vertical distance from the superior border of the lamina were the primary outcome measures for the reference of C2 pedicle screw placement. Furthermore, factors that affect the primary insertion parameters were assessed via multiple linear regression analyses.

METHOD

According to the diagnosis of BI and HRVA, the unilateral pedicles were assigned into HRVA of BI, non-HRVA of BI, HRVA of control, and non-HRVA of control groups. Subgroup analyses based on Goel types A and B were also performed. Moreover, vertebral artery (VA) anomalies that might result in potentially serious complications were identified and systematically compared.

RESULTS

The measurements of insertion parameters in BI patients with HRVA indicated a mean mediolateral angle of 27.42°, a mean cephalad angle of 43.02°, a mean surface distance of 9.74 mm, and a mean vertical distance from the superior border of the lamina of 3.85 mm. Compared with that in BI patients without HRVA, the measurements suggested that the entry point in BI patients with HRVA should be shifted upward by 0.38 mm and the trajectory should be angled cephalad by 6.05° and medially by 4.78°. In the control group, changes in the insertion parameters between HRVA and non-HRVA showed a similar trend to the BI group. Multiple linear regression showed that mediolateral angle was significantly associated with the male gender (B=-0.930, p=.017) and the diagnoses of HRVA (B=6.964, p<.001), Goel type A (B=-1.656, p=.003), and Goel type B (B=0.981, p=.030). Moreover, cephalad angle was significantly associated with the length of lateral mass (B=-0.319, p=.001) and the diagnoses of HRVA (B=3.254, p<.001) and Goel type A (B=6.924, p<.001). The VA anomalies were significantly higher in the BI group than in the control group.

CONCLUSIONS

The insertion parameters of the ideal entry point and trajectory for C2 screw placement in BI patients with HRVA were remarkably different from those of non-HRVA of BI, HRVA of control, and non-HRVA of control cohorts. Preoperative 3D computed tomography (CT) and CT angiography are highly recommended in such patients to improve intraoperative safety and reduce postoperative complications.

Complement Genetics for the Practicing Allergist Immunologist: Focus on Complement Deficiencies

Complement deficiencies have been considered to be rare for many decades, but this assumption is changing year by year. Recognition of these conditions significantly increases thanks to the availability of different testing approaches and due to clinical awareness. Furthermore, sequencing technologies (including Sanger sequencing, targeted gene panels, and whole exome/genome sequencing) may facilitate the identification of the underlying disease-causing genetic background. On the other hand, functional characterization of the identified possibly pathogenic variations and performing family studies, as illustrated by some of our cases, remain similarly important to establish a precise clinical diagnosis facilitating the most appropriate management. Here, we present 4 illustrative cases with complement deficiencies of diverse etiologies and also provide an educative, step-by-step description on how to identify the underlying cause of complement deficiency based on the results of complement laboratory testing.

Double Dome Laminoplasty: A Novel Technique for C2 Decompression

Objective

To introduce a new surgical technique - double dome laminoplasty for decompression of the entire C2 lamina and preservation of an extensor muscle insertion.

Methods

Eleven consecutive cervical myelopathy patients due to ossification of the posterior longitudinal ligament involving the Axis (C2) area were contained at this study. Direct decompression was evaluated as an increasing rate in space available cord (%) and posterior cord shift (mm) at C2 level. The Japanese Orthopaedic Association (JOA) score, visual analogue scale, and C2–7 Cobb angle in a neutral lateral x-ray were analyzed.

Results

The mean increase in space available for spinal cord at the C2 level, average posterior cord shift, and JOA recovery rate were 69.7%, 5.3±0.15 mm, and 58.0%, respectively. Cervical lordotic angle was maintained in all patients. One patient reported neck pain (visual analogue scale 6) postoperatively. No specific complications such as C2 laminar fracture or insufficient decompression were observed.

Conclusion

We recommend double dome laminoplasty for treating patients with cervical myelopathy involving the C2 area to avoid C2 laminectomy, reduce postoperative neck pain, and maintain lordotic cervical spine alignment.

Cost-effectiveness and potential value of pharmaceutical treatment of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is associated with substantial morbidity, mortality, and economic burden. With currently no approved treatment, an effective pharmaceutical intervention for this disease must be both clinically- and cost-effective.

METHODS

A Markov model was constructed to estimate the clinical outcomes, costs, and quality of life impact of a hypothetical pharmaceutical intervention. Lifetime clinical outcomes, life-years, quality-adjusted life-years (QALYs), costs (2020 $US), incremental cost-effectiveness ratios (ICERs), and economically justifiable prices (EJPs) were quantified. Only patients with fibrosis stage F2-F4 were assumed eligible to initiate pharmaceutical treatment.

RESULTS

Over a mean life expectancy of approximately 21 years in the simulated cohort, drug treatment reduced liver-related mortality by 6.0% (2.7% absolute reduction). Assuming an annual drug cost of $36,000, total discounted medical costs were $574,238 and $120,312 for drug and usual care, respectively, with discounted QALYs estimated to be 9.452 and 9.272 for the two comparators. This yielded an ICER of $2,517,676/QALY gained. The EJP of the drug at an ICER threshold of $150,000/QALY gained was $2,633, a 93% reduction from a base case. Sensitivity analyses suggest that, without a substantial decrease in the drug price, ICERs would exceed $500,000/QALY gained even with the most favorable efficacy assumptions.

CONCLUSIONS

For a pharmaceutical intervention to be considered cost-effective in the NAFLD fibrosis population, the substantial clinical benefit will need to be coupled with a modest annual price. Annual drug costs exceeding $12,000 likely will not provide reasonable value, even with favorable efficacy. More work is needed to estimate the cost-effectiveness of lifestyle modifications.

Cost-effectiveness analysis of the Parkinson's KinetiGraph and clinical assessment in the management of Parkinson's disease

AIMS

The Parkinson's KinetiGraph (PKG) is a wrist-worn movement recording system that collates continuous, objective, data during daily activities in people with Parkinson's disease (PD) providing a report for clinicians. This study explores the cost-effectiveness of adding the PKG to routine PD assessments.

METHODS

A de novo Markov model of three health states: uncontrolled, controlled and death compared PKG plus routine assessment by a Movement Disease Specialist (MDS) versus routine assessment. Uncontrolled and controlled states were based on the Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) II and III scores. The transition between health states was dependent on improvement in MDS-UPDRS II and III, and transition to death state on all cause-mortality and PD-specific relative mortality risk. Markov cycle length was yearly beyond year 1 and lifetime horizon 22 years.

LIMITATIONS

PKG evidence incorporated in this analysis is based on findings from one clinical trial. Health state utilities were mapped and the probability of patients progressing from uncontrolled to controlled health state at the second visit and beyond was derived from a bootstrap method which assumed a normal distribution for MDS-UPDRS.

RESULTS

The addition of the PKG to usual PD assessments is a cost-effective intervention. PKG plus routine assessment is associated with lower total costs compared to routine assessment (£141,950 versus £159,312) and improved quality-adjusted life years (7.88 versus 7.61), resulting in an incremental cost-effectiveness ratio of -£64,978.99 and a net monetary benefit of £22,706.37 using a £20,000 threshold. Results were robust across sensitivity and scenario analyses.

CONCLUSIONS

Management of PD involves monitoring and evaluation of symptoms to assess disease progression and ensure appropriate treatment choices. Adding the PKG to clinical assessment in routine care allows for improved and objective identification of PD motor symptoms which can be used in clinical decision making to improve patient outcomes.

Cost-effectiveness analysis of arthroscopic injection of a bioadhesive hydrogel implant in conjunction with microfracture for the treatment of focal chondral defects of the knee - an Australian perspective

AIM

JointRep is a bioadhesive hydrogel arthroscopically injected to facilitate cartilage regeneration. The cost-effectiveness of JointRep with microfracture surgery compared to microfracture alone was evaluated from the Australian healthcare system perspective, in patients with symptomatic focal chondral defects (Outerbridge Grade 3 or 4) of the knee who had failed conservative treatment and were indicated for surgery.

MATERIALS AND METHODS

A de novo Markov model comprising two health states- 'Alive' and 'Dead' was developed. Model transition probability was based on the general population mortality rates. Clinical outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, a validated patient-reported tool measuring pain, stiffness, and physical function. The utility was derived by mapping WOMAC scores to EQ-5D scores using a published algorithm. Cost inputs were based on published Australian costs from AR-DRGs, Medicare Benefits Schedule, and Prostheses List. Model outcomes included costs, Quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). Base-case analysis was conducted for a time horizon of 3 years and a cycle length of 1 year. Cost and health outcomes were discounted at 5% per annum. Sensitivity and scenario analyses were also conducted.

RESULTS

Total QALYs were estimated to be higher for JointRep with microfracture surgery (2.61) compared to microfracture surgery alone (1.66), an incremental gain of 0.95 QALY. JointRep with microfracture surgery was associated with an incremental cost of $6,022 compared to microfracture surgery alone, thus leading to an ICER of $6,328. Results were substantially robust to varying parameters in the sensitivity analyses conducted, alternative model settings and assumptions in scenario analyses.

LIMITATIONS

The clinical inputs used in the model were based on data from short duration, non-randomized, post-market clinical trial.

CONCLUSIONS

JointRep with microfracture surgery is a cost-effective treatment option compared to microfracture alone from the Australian health care system perspective.

Distinct Patterns of P1 and C2 VEP Potentiation and Attenuation in Visual Snow: A Case Report

Visual snow syndrome, characterized by persistent flickering dots throughout the visual field, has been hypothesized to arise from abnormal neuronal responsiveness in visual processing regions. Previous research has reported a lack of typical VEP habituation to repeated stimulus presentation in patients with visual snow. Yet these studies generally used pattern-reversal paradigms, which are suboptimal for measuring cortical responses to the onset of foveal stimulation. Instead, these responses are better indexed by the C2, a pattern-onset VEP peaking 100–120 ms after stimulus onset. In this case study, we analyzed the C2 and its adaptation profile in data previously collected from a single patient with visual snow using a “double-pulse” presentation paradigm. In controls, shorter intervals between stimulus pairs were associated with greater attenuation of the C2 VEP, with recovery from adaptation at longer stimulus onset asynchronies (SOAs). However, the visual snow patient showed the opposite pattern, with reduced C2 amplitude at longer SOAs despite distinct C2 peaks at the shortest SOAs. These results stand in contrast not only to the pattern of C2 VEP attenuation in controls, but also to a lack of adaptation previously reported for the pattern-onset P1 VEP in this patient. Exploratory source localization using equivalent current dipole fitting further suggested that P1 and C2 VEPs in the visual snow patient arose from distinct sources in extrastriate visual cortex. While preliminary, these results support differential patterns of VEP attenuation and potentiation within the same individual, potentially pointing toward multiple mechanisms of abnormal neuronal responsiveness in visual snow syndrome.

Proposal of Treatment Strategy for Pedicle Fractures of the C2: An Analysis of 49 Cases

Spine surgeons often confuse C2 pedicle fractures (PFs) with pars interarticularis fractures. In addition, little information is available about the characteristics and treatment strategies for C2 PFs. We sought to investigate the characteristics of C2 PFs and to propose an appropriate treatment strategy. A total of forty-nine patients with C2 PFs were included in this study. We divided these patients into unilateral and bilateral C2 PF groups. The incidence rates and characteristics of other associated C2 and C2-3 injuries, and other cervical injuries, were evaluated. In addition, treatment methods and outcomes were analyzed. Twenty-two patients had unilateral C2 PFs and twenty-seven patients had bilateral C2 PFs. Among the cases of unilateral C2 PFs, all patients had one or more other C2 fractures, and twenty patients (90.9%) had one or two C2 body fractures. Meanwhile, among the cases of bilateral C2 PF, all patients had two or more other C2 fractures and one or two C2 body fractures. In unilateral C2 PFs, three patients with C2-3 anterior slip or adjacent cervical spine (C1-3) injury underwent surgery and nineteen patients (86.4%) were treated with conservative methods. In bilateral C2 PFs, three patients with C2-3 anterior slip or SCI at C2-3 underwent surgery and twenty-four patients (88.9%) were treated with conservative methods. Our results showed that C2 PFs do not occur alone and are always accompanied by other associated C2 injuries. C2 PFs should, generally, be thought of as a more complex fracture type than hangman's fracture or dens fracture. Despite the complex fracture characteristics, most C2 PFs can be managed with conservative treatment. However, surgical treatments should be considered if the C2 PFs are accompanied by the C2-3 anterior slip and adjacent cervical spine injury.

Analyzing parsicle screws as a viable alternative to pars screws and pedicle screws for C2 posterior instrumentation fixation

Introduction

This study examined the possible clinical utility of "parsicle screws" in securing C2 instrumentation.

Methods

Ten patients' C2 vertebrae were virtually reconstructed using computer-aided design software. Pedicle, pars, and parsicle screws were virtually placed in the vertebrae.

Results

In addition to establishing the trajectory and theoretical safety of parsicle screws, this study determined that parsicle screws were significantly longer than pars screws (p = 0.005).

Conclusion

The additional length of parsicle screws may improve construct stability. As such, parsicle screws should be examined as an alternative to pars screws in patients unable to receive C2 pedicle screws.

A unique C2 domain at the C terminus of Munc13 promotes synaptic vesicle priming

Neurotransmitter release during synaptic transmission comprises a tightly orchestrated sequence of molecular events, and Munc13-1 is a cornerstone of the fusion machinery. A forward genetic screen for defects in neurotransmitter release in Caenorhabditis elegans identified a mutation in the Munc13-1 ortholog UNC-13 that eliminated its unique and deeply conserved C-terminal module (referred to as HC2M) containing a Ca²⁺-insensitive C2 domain flanked by membrane-binding helices. The HC2M module could be functionally replaced in vivo by protein domains that localize to synaptic vesicles but not to the plasma membrane. HC2M is broadly conserved in other Unc13 family members and is required for efficient synaptic vesicle priming. We propose that the HC2M domain evolved as a vesicle/endosome adaptor and acquired synaptic vesicle specificity in the Unc13ABC protein family.

Sensors and Communication Simulation for Unmanned Traffic Management

Unmanned traffic management (UTM) systems will become a key enabler to the future drone market ecosystem, enabling the safe concurrent operation of both manned and unmanned aircrafts. Currently, these systems are usually tested by performing real scenarios that are costly, limited, hardly scalable, and poorly repeatable. As a solution, in this paper we propose an agent-based simulation platform, implemented through a micro service architecture, which may simulate UTM information sources, such as flight plans, telemetry messages, or tracks from a surveillance network. The final objective of this simulator is to use these information streams to perform a system-level evaluation of UTM systems both in the pre-flight and in-flight stages. The proposed platform, with a focus on simulation of communications and sensors, allows to model UTM actors' behaviors and their interactions. In addition, it also considers the manual definition of events to simulate unexpected behaviors/events (contingencies), such as communications failures or pilots' actions. In order to validate our architecture, we implemented a simulator that considers the following actors: drones, pilots, ground control stations, surveillance networks, and communications networks. This platform enables the simulation of the drone trajectory and control, the C2 (command and control) link, drone detection by surveillance sensors, and the communication of all agents by means of a mobile communications network. Our results show that it is possible to truthfully recreate complex scenarios using this simulator, mitigating the disadvantages of real testbeds.

Percutaneous Image-Guided Anterior Screw Fixation of the Odontoid Process

PURPOSE

To describe the technique of percutaneous image-guided anterior screw fixation of the odontoid process in five patients using hydrodissection of the jugulo-carotid and pre-vertebral spaces.

METHODS AND MATERIALS

Between 03/2018 and 03/2020, five patients from two university hospitals underwent a percutaneous image-guided anterior screw fixation of the odontoid process for one pathological fracture, two impending fractures and two traumatic fractures of the dens. Technical success was defined as a satisfactory positioning of the screw in the odontoid. Detailed data with the number and type of needles required, the time to perform hydrodissection, the volume of fluid used, the time for bone access, the size and lengths of the screws used, technical success, complications, clinical outcomes and follow-up were retrospectively assessed.

RESULTS

Technical success was achieved in 100% (5/5 cases), with a mean volume of hydrodissection of 218 ± 8.4 mL (range 210-230). Mean total procedure time was 112 ± 34 min (range 70-160). The lengths of the screws ranged from 30 mm to 55 mm. Additional cementoplasty was performed in the three malignant cases. VAS scores dropped on a 10-point scale from mean 5.8 ± 2.2 pre-procedure to 0.8 ± 0.4 after the procedure. No major complication occurred.

CONCLUSION

Percutaneous image-guided anterior screw fixation of the odontoid process using hydrodissection of the jugulo-carotid and pre-vertebral spaces is technically feasible and seems safe.

Cost of microvascular complications in people with diabetes from a public healthcare perspective: a retrospective database study in Brazil

AIM

To evaluate direct medical costs incurred by patients with diabetes in the periods before and after experiencing a microvascular complication from a Brazilian public healthcare system perspective.

MATERIALS AND METHODS

This was a retrospective, observational study using the Brazilian Unified Health System (DATASUS) database. Direct medical costs (hospitalization and outpatient) were extracted for patients with evidence of diabetes and a microvascular complication (January 2012-December 2018) and converted to 2019 US Dollars (USD). Length of hospital stays was also extracted. Mixed-effects logistic regression explored associations between demographic/clinical characteristics and incurrence of high direct medical costs (defined as the highest tertile of the annual costs ranked by median cost in the total population).

RESULTS

In total, 2,096 patients with diabetes experienced a microvascular complication and met study inclusion/exclusion criteria. Median [interquartile range] annual costs (USD/patient) were 176.3 [91.0; 481.2] at baseline, increasing to 1,678.5 [287.0; 6,908.4] and 5,172.4 [274.8; 7,395.9] in the first and second year after the complication, respectively. Median hospital stay was 2.0 and 3.0 days at baseline and in the first year, respectively. The odds of incurring high costs were substantially elevated in the first and second years (odds ratios of 69.9 and 84.7, respectively, vs. baseline, both p < .001).

LIMITATIONS

The DATASUS database covers secondary and tertiary care (not primary), adding selection bias to our sample. Additionally, our findings may not apply to the entire Brazilian population, as around 25% have some access to private healthcare.

CONCLUSIONS

This study demonstrates a large increase in costs, from the perspective of the Brazilian public healthcare system, in patients with diabetes after experiencing a microvascular complication compared with pre-complication costs. In addition to providing up-to-date cost estimates, our findings highlight the need to appraise the cost-effectiveness of evidence-based strategies that reduce the risk of diabetes-related microvascular complications in Brazilian patients.

Treatment of spinal cord compression caused by C2 osteochondroma with reconstruction and fusion after total resection: Case report and literature review

Context: Osteochondroma is the most common benign tumor of the bone, but spinal osteochondroma is rare. We report a case of cervical osteochondroma in multiple exostoses arising from the lamina of the C2 vertebra, presenting with features of compressive myelopathy in a 22-year-old male. Total resection of the tumor and atlantoaxial fixation and fusion after reconstruction of the C1 posterior arch were performed.Findings: The patient recovered significantly. He was asymptomatic and no sign of recurrence was observed after one-year follow-up.Conclusions: Osteochondroma should be considered as a rare cause of spinal cord compression. Entire removal of the tumor will result in complete decompression and can reduce the risk of recurrence. We provide a new approach to reconstruct after resection.

An Intraoperative Surprise! A Rare Case Report of Primary Craniovertebral Junction Hydatid Disease Mimicking a Bony Tumor

BACKGROUND

Craniovertebral junction (CVJ) hydatid disease, although rare, forms an important differential diagnosis of CVJ bony pathologies, especially in endemic areas due to the sheer volume of cases presented there. The authors report a rare case of CVJ hydatid disease mimicking a bony expansile tumor on imaging.

CASE DESCRIPTION

A 21-year-old woman presented with a left-sided neck tilt and pain for 3 months, intermittent low-grade fever, and features of high cervical myelopathy (Nurick grade II). Magnetic resonance imaging and computed tomography imaging showed a solid enhancing mass with numerous small cystic areas with bony erosion of the basiocciput, C1 and C2 vertebrae, suggestive of an expansile bony lesion (osteoblastoma/giant cell tumor/aneurysmal bone cyst). She underwent a posterior approach for decompression and spinal fixation, and multiple clear grape-like cysts were encountered that were confirmed to be hydatid cysts on histopathology. All visible cysts were excised and instrumented fusion of the CVJ performed. Albendazole was continued for 6 weeks and at 3 months' follow-up, the patient remains asymptomatic with no recurrence on imaging.

CONCLUSIONS

The authors conclude that in tropical regions, hydatid disease of the cervical spine should be considered in the differential diagnosis of patients presenting with high cervical compressive myelopathy, especially when associated with fever. Spinal hydatosis may mimic a bony lesion on imaging and should be kept in mind, as in addition to routine decompression, use of scolicidal agents and intact removal of cysts have a significant effect on reducing the recurrence rate and improving the outcome.

ARGX-117, a therapeutic complement inhibiting antibody targeting C2

Background

Activation of the classical and lectin pathway of complement may contribute to tissue damage and organ dysfunction of antibody-mediated diseases and ischemia-reperfusion conditions. Complement factors are being considered as targets for therapeutic intervention.

Objective

We sought to characterize ARGX-117, a humanized inhibitory monoclonal antibody against complement C2.

Methods

The mode-of-action and binding characteristics of ARGX-117 were investigated in detail. Furthermore, its efficacy was analyzed in in vitro complement cytotoxicity assays. Finally, a pharmacokinetic/pharmacodynamic study was conducted in cynomolgus monkeys.

Results

Through binding to the Sushi-2 domain of C2, ARGX-117 prevents the formation of the C3 proconvertase and inhibits classical and lectin pathway activation upstream of C3 activation. As ARGX-117 does not inhibit the alternative pathway, it is expected not to affect the antimicrobial activity of this complement pathway. ARGX-117 prevents complement-mediated cytotoxicity in in vitro models for autoimmune hemolytic anemia and antibody-mediated rejection of organ transplants. ARGX-117 exhibits pH- and calcium-dependent target binding and is Fc-engineered to increase affinity at acidic pH to the neonatal Fc receptor, and to reduce effector functions. In cynomolgus monkeys, ARGX-117 dose-dependently reduces free C2 levels and classical pathway activity. A 2-dose regimen of 80 and 20 mg/kg separated by a week, resulted in profound reduction of classical pathway activity lasting for at least 7 weeks.

Conclusions

ARGX-117 is a promising new complement inhibitor that is uniquely positioned to target both the classical and lectin pathways while leaving the alternative pathway intact.

Farewell to Professor David Yaffe - A pillar of the myogenesis field

It is with great sadness that we have learned about the passing of Professor David Yaffe (1929-2020, Israel). Yehi Zichro Baruch - May his memory be a blessing. David was a man of family, science and nature. A native of Israel, David grew up in the historic years that preceded the birth of the State of Israel. He was a member of the group that established Kibbutz Revivim in the Negev desert, and in 1948 participated in Israel's War of Independence. David and Ruth eventually joined Kibbutz Givat Brenner by Rehovot, permitting David to be both a kibbutz member and a life-long researcher at the Weizmann Institute of Science, where David received his PhD in 1959. David returned to the Institute after his postdoc at Stanford. Here, after several years of researching a number of tissues as models for studying the process of differentiation, David entered the myogenesis field and stayed with it to his last day. With his dedication to the field of myogenesis and his commitment to furthering the understanding of the People and the Land of Israel throughout the international scientific community, David organized the first ever myogenesis meeting that took place in Shoresh, Israel in 1975. This was followed by the 1980 myogenesis meeting at the same place and many more outstanding meetings, all of which brought together myogenesis, nature and scenery. Herein, through the preparation and publication of this current manuscript, we are meeting once again at a "David Yaffe myogenesis meeting". Some of us have been members of the Yaffe lab, some of us have known David as his national and international colleagues in the myology field. One of our contributors has also known (and communicates here) about David Yaffe's earlier years as a kibbutznick in the Negev. Our collective reflections are a tribute to Professor David Yaffe. We are fortunate that the European Journal of Translational Myology has provided us with tremendous input and a platform for holding this 2020 distance meeting "Farwell to Professor David Yaffe - A Pillar of the Myogenesis Field".

The C2 Cortical Screw, an Alternative Fixation Technique for the C2 Segment During High Cervical Spine Surgery: Technical Note

BACKGROUND

For posterior fixation of C2 vertebra (the axis), several fixation techniques such as pedicle screw, laminar screw, and pars screw have been reported. A pedicle screw (PS) is considered the strongest among the techniques, but certain situations make PS fixation impossible or difficult. These include patients with a narrow C2 pedicle or high-riding vertebral artery. We introduced an alternative screw technique for C2 that addressed the aforementioned problems with safely placing it, which we termed a cortical screw (CS) for C2.

METHODS

Among a total of 28 cases using C2 CS for high cervical spine surgery, 2 cases using C2 CS were described. One patient was a 76-year old woman with a gait disturbance and myelopathic symptoms and diagnosed with C1-C2 myelopathy and translational instability. The other case was 54-year old man with posterior neck pain after traffic accident and diagnosed with C1-C2 fracture-dislocation. We used the C2 CS as an alternative technique for high cervical spine surgery in these patients and describe the ideal entry point and trajectory.

RESULTS

A postoperative computed tomography scan confirmed proper positioning of the C1 posterior arch screw and C2 CS, with satisfactory reduction of the C2 dens and adequate restoration of the C1-C2 spinal canal. The patient experienced no screw-related postoperative complications, and postoperative 1-year computed tomography images showed that solid union and good alignment of C1-2 segment was achieved.

CONCLUSIONS

C2 CS can be suitable alternative for C2 screw fixation technique in posterior high cervical spine fusion surgery.

Inherited C2-complement deficiency: variable clinical manifestation (case reports and review)

C2 deficiency represents the most frequent type of a complement deficiency. Clinical manifestation includes infections caused by encapsulated bacteria (Steptococcus pneumoniae, Neisseria meningitidis) such as meningitis, gonitis, pneumonia or septicaemia. A causative treatment has not been available yet. A prophylactic vaccination and/or a long-term antibiotics prophylaxis are recommended. Here we report 2 patients from 2 unrelated families. The first patient suffered from recurrent otitis in his childhood. He underwent osteomyelitis, meningitis complicates with hear-loss, and one episode of pneumonia during adulthood. The second index patient underwent uncomplicated meningitis in his preschool age. He has been treated for recurrent upper-airways infections later. His sister has been completely asymptomatic. The deletion 28 bp (c.841-849+19del28) in C2-gene was detected in all of them in homozygous form. Our paper highlights the variability of a clinical manifestation in homozygous carriers, ranged from asymptomatic cases to patients with history of severe complications. The diagnosis is frequently made even in adulthood.

Tailored Posterior-Only Approach for C2 Vertebral Body Lesions: Our Surgical Experience in 10 Patients

BACKGROUND

C2 vertebral body (axis) lesions are often approached anteriorly and combined with posterior stabilization of the craniovertebral junction (CVJ). The anterior approach has its limitations. A posterolateral corridor is an alternative access to the C2 body lesions, and this alone may suffice in selected cases. We describe our experience with C2 body lesions, dealt primarily through a posterior approach, and propose an algorithm in the management of such cases.

METHODS

Ten patients with axis lesions were operated through a midline posterior approach followed by posterior stabilization of the CVJ in the same sitting. Their preoperative and follow-up clinico-radiologic details were reviewed.

RESULTS

The lesions included aneurysmal bone cysts (n = 2), fibrous dysplasia (n = 2), chordoma (n = 2), Ewing sarcoma (n = 1), metastases (n = 1), post-traumatic malunion (n = 1), and post-inflammatory deformity (n = 1). All patients presented with worsening neck pain. Five also had spastic quadriparesis. There were no perioperative complications. All showed clinical improvement at follow-up. Only 2 patients (chordoma: n = 1; aneurysmal bone cyst: n = 1) required an additional anterior procedure.

CONCLUSIONS

Adequate debulking or total excision of lesion, neural decompression, and stabilization of the CVJ for axis body lesions can be achieved through a single midline posterior approach in most cases. If required, an anterior approach may be later added depending on the final histopathology.

subaxial cervical upper-most instrumented vertebrae

Background

The study aims to evaluate differences in alignment and clinical outcomes between surgical cervical deformity (CD) patients with a subaxial upper-most instrumented vertebra (UIV) and patients with a UIV at C2. Use of CD-corrective instrumentation in the subaxial cervical spine is considered risky due to narrow subaxial pedicles and vertebral artery anatomy. While C2 fixation provides increased stability, the literature lacks guidelines indicating extension of CD-corrective fusion from the subaxial spine to C2.

Methods

Included: operative CD patients with baseline (BL) and 1-year postop (1Y) radiographic data, cervical UIV ≥ C2. Patients were grouped by UIV: C2 or subaxial (C3-C7) and propensity score matched (PSM) for BL cSVA. Mean comparison tests assessed differences in BL and 1Y patient-related, radiographic, and surgical data between UIV groups, and BL-1Y changes in alignment and clinical outcomes.

Results

Following PSM, 31 C2 UIV and 31 subaxial UIV patients undergoing CD-corrective surgery were included. Groups did not differ in BL comorbidity burden (P=0.175) or cSVA (P=0.401). C2 patients were older (64 vs. 58 yrs, P=0.010) and had longer fusions (9 vs. 6 levels, P=0.002). Overall, patients showed BL-1Y improvements in TS-CL (P<0.001), cSVA (P=0.005), McGS (P=0.004). Cervical flexibility was maintained at 1Y regardless of UIV, assessed by CL flexion (-0.2° vs. 6.0°, P=0.115) and extension (13.9° vs. 9.9°, P=0.366). While both subaxial and C2 patients showed BL-1Y improvements in McGS (both P<0.030), C2 patients improved to a larger degree (7.3° vs. 6.2°). Between UIV groups, there were no differences in BL-1Y changes in HRQLs, overall complication rates, or operative complication rates (all P>0.05).

Conclusions

C2 UIV patients showed similar cervical range of motion and baseline to 1-year functional outcomes as patients with a subaxial UIV. C2 UIV patients also showed greater baseline to 1-year horizontal gaze improvement and had complication profiles similar to subaxial UIV patients, demonstrating the radiographic benefit and minimal functional loss associated with extending fusion constructs to C2. In the treatment of adult cervical deformities, extension of the reconstruction construct to the axis may allow for certain clinical benefits with less morbidity than previously acknowledged.

Complement Nomenclature-Deconvoluted

In 2014, specific recommendations for complement nomenclature were presented by the complement field. There remained some unresolved designations and new areas of ambiguity, and here we propose solutions to resolve these remaining issues. To enable rapid understanding of the intricate complement system and facilitate therapeutic development and application, a uniform nomenclature for cleavage fragments, pattern recognition molecules (PRMs) and enzymes of the lectin pathway and regulatory proteins of the complement system are proposed, and a standardization of language to designate different activation states of complement components is recommended.

Association of C2, a derivative of the radial artery pressure waveform, with new onset of type 2 diabetes mellitus: the MESA study

BACKGROUND

Although microvascular dysfunction is known to result from diabetes, it might also lead to diabetes. Lower values of C2, a derivative of the radial artery pressure waveform, indicate microvascular dysfunction and predict hypertension and cardiovascular disease (CVD). We studied the association of C2 with incident diabetes in subjects free of overt CVD.

METHODS

Among multi-ethnic participants (n = 5214), aged 45-84 years with no diabetes, C2 was derived from the radial artery pressure waveform. Incident diabetes (N = 651) was diagnosed as new fasting glucose ≥ 126 mg/dL or antidiabetic medicine over ~ 10 years. The relative incidence density (RID) for incident diabetes per standard deviation (SD) of C2 was studied during ~ 10 years follow-up using four levels of adjustment.

RESULTS

Mean C2 at baseline was 4.58 ± 2.85 mL/mmHg × 100. The RID for incident diabetes per SD of C2 was 0.90 (95% CI 0.82-0.99, P = 0.03). After adjustment for demographics plus body size, the corresponding RID was 0.81 (95% CI 0.73-0.89, P < 0.0001); body mass index (BMI) was the dominant covariate here. After adjustment for demographics plus cardiovascular risk factors, the RID was 0.98 (95% CI 0.89, 1.07, P = 0.63). After adjustment for all the parameters in the previous models, the RID was 0.87 (95% CI 0.78, 0.96, P = 0.006).

CONCLUSIONS

In a multi-ethnic sample free of overt CVD and diabetes at baseline, C2 predicted incident diabetes after adjustment for demographics, BMI and CVD risk factors. Differences in arterial blood pressure wave morphology may indicate a long-term risk trajectory for diabetes, independently of body size and the classical risk factors.

Quantification of human complement C2 protein using an automated turbidimetric immunoassay

BACKGROUND

The measurement of complement components is clinically useful where a deficiency is suspected, or where excessive activation and consumption are present in disease. C2 deficiency carries an increased risk of developing systemic lupus erythematosus, recurrent infections and atherosclerosis. In this study, we have evaluated The Binding Site's Human Complement C2 SPAPLUS® assay.

METHODS

Linearity was tested using 13 sample dilutions covering the standard measuring range. Within- and between-assay variabilities were calculated using five samples with different C2 concentrations. The correlation between C2 concentrations in EDTA-plasma and serum was assessed, as was the correlation between C2 measurements by the automated assay and radial immunodiffusion. C2 concentrations were compared with CH50 activity, and quantified in individuals with homozygous or heterozygous C2 deficiency, acquired angioedema and patients with chronic inflammatory conditions.

RESULTS

The assay was linear across the measuring range (3.8-42.3 mg/L). Intra- and interassay variability were 2.3%-3.8% and 0%-3.3%, respectively. Comparison between C2 measurements in EDTA-plasma and serum provided a strong correlation (p<0.0001, R2=0.82, slope 0.92), as did the correlation between the automated and radial immunodiffusion methods (p<0.0001, R2=0.89, slope 1.07). A positive correlation between C2 concentration and CH50 activity was demonstrated (p<0.0001, R2=0.48). Significant differences were observed between the median C2 concentrations obtained in healthy controls and the patient clinical samples, with homozygous C2-deficient patients giving below detectable results.

CONCLUSIONS

This C2 SPAPLUS® assay allows the automated, rapid and precice quantification of complement C2 protein and could therefore be considered as a replacement for older, more time-consuming methods.

Polyphosphoinositide-Binding Domains: Insights from Peripheral Membrane and Lipid-Transfer Proteins

Within eukaryotic cells, biochemical reactions need to be organized on the surface of membrane compartments that use distinct lipid constituents to dynamically modulate the functions of integral proteins or influence the selective recruitment of peripheral membrane effectors. As a result of these complex interactions, a variety of human pathologies can be traced back to improper communication between proteins and membrane surfaces; either due to mutations that directly alter protein structure or as a result of changes in membrane lipid composition. Among the known structural lipids found in cellular membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the membrane-anchored precursor of low-abundance regulatory lipids, the polyphosphoinositides (PPIn), which have restricted distributions within specific subcellular compartments. The ability of PPIn lipids to function as signaling platforms relies on both non-specific electrostatic interactions and the selective stereospecific recognition of PPIn headgroups by specialized protein folds. In this chapter, we will attempt to summarize the structural diversity of modular PPIn-interacting domains that facilitate the reversible recruitment and conformational regulation of peripheral membrane proteins. Outside of protein folds capable of capturing PPIn headgroups at the membrane interface, recent studies detailing the selective binding and bilayer extraction of PPIn species by unique functional domains within specific families of lipid-transfer proteins will also be highlighted. Overall, this overview will help to outline the fundamental physiochemical mechanisms that facilitate localized interactions between PPIn lipids and the wide-variety of PPIn-binding proteins that are essential for the coordinate regulation of cellular metabolism and membrane dynamics.

Increasing spatial resolution of photoregulated GTPases through immobilized peripheral membrane proteins

Light-induced dimerizing systems, e.g. iLID, are an increasingly utilized optogenetics tool to perturb cellular signaling. The major benefit of this technique is that it allows external spatiotemporal control over protein localization with sub-cellular specificity. However, when it comes to local recruitment of signaling components to the plasmamembrane, this precision in localization is easily lost due to rapid diffusion of the membrane anchor. In this study, we explore different approaches of countering the diffusion of peripheral membrane anchors, to the point where we detect immobilized fractions with iFRAP on a timescale of several minutes. One method involves simultaneous binding of the membrane anchor to a secondary structure, the microtubules. The other strategy utilizes clustering of the anchor into large immobile structures, which can also be interlinked by employing tandem recruitable domains. For both approaches, the anchors are peripheral membrane constructs, which also makes them suitable for in vitro use. Upon combining these slower diffusing anchors with recruitable guanine exchange factors (GEFs), we show that we can elicit much more localized morphological responses from Rac1 and Cdc42 as compared to a regular CAAX-box based membrane anchor in living cells. Thanks to these new slow diffusing anchors, more precisely defined membrane recruitment experiments are now possible.

Treatment of Axis Ring Fractures: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)

STUDY DESIGN

Narrative literature review and expert recommendation.

OBJECTIVE

To establish treatment recommendations for axis ring fractures based on the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma.

METHODS

This recommendation summarizes the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma with regard to the treatment of axis ring fractures based on a narrative literature review.

RESULTS

Typical "hangman's fractures" with bilateral separation of the neural arch from C2 and atypical "hangman's fractures" with irregular fracture morphology are described. Computed tomography is the "gold" standard used to detect and analyse these fractures adequately. Furthermore, the detection of vertebral artery integrity is necessary. To classify axis ring fractures, the Levine-Edwards or Josten classification is recommended. In particular, the integrity of the C2/3 disc and the integrity of the anterior longitudinal ligament are used to determine the treatment strategy. While Levine-Edwards type I and type IIA (Josten type 1 and 2) fractures should be treated conservatively, Levine type II and type III (Josten type 3 and 4) fractures should be treated operatively. Levine-Edwards type II fractures will be predominately treated by anterior C2/3 fusion. Levine-Edwards type III fractures have to be primary reduced, if an anterior fusion is planned (anterior cervical discectomy and fusion [ACDF] C2/3). If a closed reduction of a type III fracture is impossible, an open reduction and posterior fixation/fusion is the treatment of choice.

CONCLUSION

Conservative treatment is predominantly reserved for Levine-Edwards I and IIA fractures. Operative treatment should be performed in case of Levine-Edwards II and III fractures.