Accuracy of 3D fluoroscopy-navigated anterior transpedicular screw insertion in the cervical spine: an experimental study

Purpose

The technique of pedicle screw stabilization is finding increasing popularity for use in the cervical spine. Implementing anterior transpedicular screws (ATPS) in cervical spine offers theoretical advantages compared to posterior stabilization. The goal of the current study was the development of a new setting for navigated insertion of ATPS, combining the advantage of reduced invasiveness of an anterior approach with the technical advantages of navigation.

Methods

20 screws were implanted in levels C3 to C6 of four cervical spine models (SAWBONES^® Cervical Vertebrae with Anterior Ligament) with the use of 3D fluoroscopy navigation system [Arcadis Orbic 3D, Siemens and VectorVision fluoro 3D trauma software (BrainLAB)]. The accuracy of inserted screws was analyzed according to postoperative CT scans and following the modified Gertzbein and Robbins classification.

Results

20 anterior pedicle screws were placed in four human cervical spine models. Of these, eight screws were placed in C3, two screws in C4, six screws in C5, and four screws in C6. 16 of 20 screws (80 %) reached a grade 1 level of accuracy according to the modified Gertzbein and Robbins Classification. Three screws (15 %) were grade 2, and one screw (5 %) was grade 3. Grade 4 and 5 positions were not evident. Summing grades 1 and 2 together as “good” positions, 95 % of the screws achieved this level. Only a single screw did not fulfill these criteria.

Conclusion

The setting introduced in this study for navigated insertion of ATPS into cervical spine bone models is well implemented and shows excellent results, with an accuracy of 95 % (Gertzbein and Robbins grade 2 or better). Thus, this preliminary study represents a prelude to larger studies with larger case numbers on human specimens.

     

Progression of Aortic Regurgitation After Different Repair Techniques for Congenital Aortic Valve Stenosis

We sought to characterize the incidence of AR progression and determine risk factors for AR progression in a consecutive series of infants and children after surgical correction of congenital aortic valvular and supravalvular stenosis. N = 30 patients underwent repair of the aortic valve for isolated congenital aortic valve stenosis (n = 14, 47 %) or combined with aortic regurgitation (AR, n = 16, 53 %). N = 27 (90 %) had a valvular and n = 3 patients (10 %) presented with supravalvular pathology of their aortic valve. In n = 16 patients (53 %) a bicuspid and in n = 2 (6 %) patients, a unicuspid valve was present. Comparative survival was analyzed using the Cox model and log-rank calculations. Log-rank calculations were performed for variables reaching statistical significance in order to identify differences in survival between groups. Commissurotomy was performed in n = 20 patients, patch implantation in n = 4, cusp shaving in n = 8, cusp prolapse correction in n = 3, and cusp augmentation in n = 4 patients. In patients with combined dysfunction and preoperative AR, AR was successfully reduced by the initial procedure, and postoperatively the overall median AR grade was 1+ (range 0–2.5+, p = 0.001, for AR reduction among patients with any grade of preoperative AR). By the time of follow-up echocardiography, the median AR grade had significantly progressed toward 1.5+ (p = 0.004). At the time of mid-term follow-up at 3.2 years, none of the patients had moderate or severe AR grades >2.5+. Patients with a monocuspid aortic valve and patients who had some kind of patch implantation into their cusps or commissures or shaving of thickened cusps were more likely to present with progression of aortic regurgitation. Monocuspid aortic valve and patch implantation, as well as cusp shaving, are probably linked to AR progression. The standard procedure of commissurotomy results in an absolute rate of AR progression of 40 % over a medium-term follow-up period.     

Rekonstruktion von Segmentdefekten der langen Röhrenknochen

Surgery of malignant tumors and the subsequent outcome after treatment of complicated fracture situations of long bones often result in major bone defects. In addition to bridging of defects and stabilization with allogenic implants, defect reconstruction by callus distraction with segment transport and vascularized free fibula transfer are the procedures of choice for defect reconstruction in long bones. The heterogeneity of the causes of large bone defects and specific comorbidities of the patients require a differentiated approach. The indications and characteristics of the various surgical approaches and current developments in procedures for reconstruction of large defects in long bones are presented.     

Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs) were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour) for 8 weeks. Training intensity was determined within non-specific (cycling or running) and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m) and one non-specific (30s cycling or 200m running) all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa) and glucose (BGL) 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO₂ peak) was significantly increased (+17%; p = 0.01) in both groups and highly correlated with the sprint performance (r = -0.71). BLa values decreased significantly (-18%, p = 0.02) after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04) in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group.

Key points

• In addition to a highly developed aerobic performance inline speed skaters also require a highly trained anaerobic capacity to be effective in the sprint sections such as the mass start, tactical attacks and finish line sprint.
• An 8-week low-intensity endurance training program of either cycling or running training combined with additional routine training improves classical aerobic characteristics (17% increase of VO₂ peak), as well as values for acceleration and speed.
• Athletes who trained in the running group demonstrated a higher reliance on the fat metabolism in the sport-specific post-testing.
• The significant reduction in anaerobic ATP turnover during repeated sprints appears to be partially compensated by an increase in VO₂ in subsequent sprint. The results revealed a close relationship between the aerobic capacity and sprint performance in inline speed skating.

Key words: Aerobic metabolism, blood glucose concentration, all-out sprint test     

Differential removal of human pathogenic viruses from sewage by conventional and ozone treatments

Sewage contains a mixed ecosystem of diverse sets of microorganisms, including human pathogenic viruses. Little is known about how conventional as well as advanced treatments of sewage, such as ozonation, reduce the environmental spread of viruses. Analyses for viruses were therefore conducted for three weeks in influent, after conventional treatment, after additional ozonation, and after passing an open dam system at a full-scale treatment plant in Knivsta, Sweden. Viruses were concentrated by adsorption to a positively charged filter, from which they were eluted and pelleted by ultracentrifugation, with a recovery of about 10%. Ion Torrent sequencing was used to analyze influent, leading to the identification of at least 327 viral species, most of which belonged to 25 families with some having unclear classification. Real-time PCR was used to test for 21 human-related viruses in inlet, conventionally treated, and ozone-treated sewage and outlet waters. The viruses identified in influent and further analyzed were adenovirus, norovirus, sapovirus, parechovirus, hepatitis E virus, astrovirus, pecovirus, picobirnavirus, parvovirus, and gokushovirus. Conventional treatment reduced viral concentrations by one to four log10, with the exception of adenovirus and parvovirus, for which the removal was less efficient. Ozone treatment led to a further reduction by one to two log10, but less for adenovirus. This study showed that the amount of all viruses was reduced by conventional sewage treatment. Further ozonation reduced the amounts of several viruses to undetectable levels, indicating that this is a promising technique for reducing the transmission of many pathogenic human viruses.     

Participatory Budgeting: Could It Diminish Health Disparities in the United States?

Participatory budgeting (PB)—a democratic process where ordinary residents decide directly how to spend part of a public budget—has gained impressive momentum in US municipalities, spreading from one pilot project in Chicago’s 49th ward in 2009 to 50 active PB processes across 14 cities in 2016–2017. Over 93,600 US residents voted in a PB process in 2015–2016, deciding over a total of about $49.5 million and funding 264 projects intended to improve their communities. The vast majority of US PB processes take place in large urban centers (e.g., New York City, Chicago, Seattle, Boston), but PB has also recently spread to some smaller cities and towns [1]. Figure 1 illustrates the growth of PB processes in the USA, and within New York City and Chicago council districts specifically.

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Fig. 1 Participatory budgeting in the USA has grown from 1 process in 2009–2010 to 50 processes in 2016–2017

PB constitutes a rare form of public engagement in that it typically comprises several distinct stages that encourage residents to participate from project idea collection to project implementation (see Fig. 2). The decisive public vote in US PB is practically binding as elected officials commit to implementing the public decision at the outset of the process. Moreover, all current PB processes in the USA have expanded voting rights to residents under 18 years old and to non-citizens. Under President Obama, the White House recognized PB as a model for open governance. Participatory Budgeting Project, a nonprofit organization that advocates for PB, won the 2014 Brown Democracy Medal, which recognizes the best work being done to advance democracy in the USA and internationally.

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Fig. 2 Typical stages of a participatory budgeting process in the USA

PB has been lauded for its potential to energize local democracy, contribute to more equitable public spending and help reduce inequality [2, 3]. Social justice goals have been explicit in US PB from the start. Grassroots advocates, technical assistance providers, and many elected officials who have adopted it emphasize that PB must focus on engaging underrepresented and marginalized communities [2, 4, 5]. PB steering committees have specified equity and inclusiveness goals in PB rule books [6, 7]. The most conclusive research so far on PB’s potential to reduce social inequalities, however, comes from Brazil, where PB started in 1989. In Brazil, PB has been associated with a reduction in extreme poverty, better access to public services, greater spending on sanitation and health services, and, most notably, a reduction in child and infant mortality [8, 9].In this paper, we outline three mechanisms by which PB could affect health disparities in US municipalities: First, by strengthening residents’ psychological empowerment; second, by strengthening civic sector alliances; and third, by (re)distributing resources to areas of greatest need. We summarize the theoretical argument for these impacts, discuss the existent empirical evidence, and highlight promising avenues for further research.     

Evaluation of a new pooling strategy based on leukocyte count for rapid quantification of allele frequencies

BACKGROUND: Allele frequencies of single-nucleotide polymorphisms (SNPs) can be quantified from DNA pools. The conventional preparation of DNA pools requires DNA isolation and quantification for each blood sample. We hypothesized that pooling of whole blood samples according to their leukocyte count, which determines DNA content, would be as reliable as the conventional pooling method but much less tedious to perform. METHODS: We collected 100 whole blood samples and measured the leukocyte count. Samples were frozen until further use. After thawing, pools were generated by combining aliquots containing an equal number of leukocytes. In parallel, DNA was extracted from another aliquot, DNA concentration was measured, and DNA concentration-based pools were assembled. All original samples were genotyped directly using 4 different SNP assays to obtain the exact allele frequencies in the pool. In addition, samples of known genotypes were mixed according to the DNA concentration or the leukocyte count to generate artificial samples of known allele frequencies. We analyzed pools and mixes in triplicate by pyrosequencing and calculated allelic frequencies. RESULTS: Leukocyte and DNA pooling provided equally accurate and precise SNP frequencies comparable to published data. CONCLUSION: DNA and leukocyte pooling are both suitable strategies to determine allele frequencies in frozen samples. The leukocyte pooling approach is much less tedious, quicker, and less expensive. It should be always considered if leukocyte counts are available.     

In vivo monitoring of implant osseointegration in a rabbit model using acoustic sound analysis

Implant osseointegration can currently only be assessed reliably post mortem. A novel method that relies on the principle of acoustic sound analysis was developed to enable examination of the longitudinal progress of osseointegration. The method is based on a magnetic sphere inside a hollow cylinder of the implant. By excitation using an external magnetic field, collision of the sphere inside the implant produces a sound signal. Custom‐made titanium implants equipped thusly were inserted in each lateral femoral epicondyle of 20 New Zealand White Rabbits. Two groups were investigated: Uncoated, machined surface versus antiadhesive surface; and calcium phosphate‐coated surface versus antiadhesive surface. The sound analysis was performed postoperatively and weekly. After 4 weeks, the animals were euthanized, and the axial pull‐out strengths of the implants were determined. A significant increase in the central frequency was observed for the loose implants (mean pull‐out strength 21.1 ± 16.9 N), up to 6.4 kHz over 4 weeks. In comparison, the central frequency of the osseointegrated implants (105.2 ± 25.3 N) dropped to its initial value. The presented method shows potential for monitoring the osseointegration of different implant surfaces and could considerably reduce the number of animals needed for experiments. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:606–612, 2014.     

Pain Medication Requirements After Sacropexy and Combination Interventions

Background and Objectives:

Laparoscopic surgery is associated with reduced morbidity, and postoperative pain is reduced. The aim of this study was to assess postoperative pain intensity, analgesic requirements, and the influence of cofactors after laparoscopic sacral colpopexy.

Methods:

The study assessed 287 patients treated with laparoscopic sacropexy for genital prolapse with a Pelvic Organ Prolapse Quantification grade >1. Patients were asked to evaluate their pain postoperatively using a 4-point verbal pain rating scale. In addition, medical records were analyzed regarding the requirement for analgesic medication.

Results:

Patients distinguished between abdominal pain and shoulder pain after laparoscopy. Abdominal pain reached maximum severity on day 1 and showed a good response to nonsteroidal antiphlogistics, whereas shoulder pain was rarely found (6.27%). Of the patients, 38% required no pain treatment or required 1 dose at most. The need for pain medication reached its climax on day 1 and decreased during the 5 following days. Non-opioid analgesics provided a sufficient therapeutic effect.

Conclusion:

Laparoscopic sacropexy is associated with a moderate degree of postoperative pain. Non-opioid analgesics should be preferred as first-line therapy. The typical shoulder-tip pain showed only a low prevalence in our study group. From our point of view, the low rate of shoulder-tip pain corresponded with the low intra-abdominal carbon dioxide pressure.     

Präsentismus vermeiden – Arbeitsbereitschaft fördern. Ein Zielkonflikt der Pandemieplanung?

Introduction

Employees are recommended to stay at home when they show symptoms of an acute respiratory infection. Yet, in case of an influenza pandemic another challenge is to promote the employees’ high willingness to report to work. For pandemic planning this raises the question, whether there is a conflict between these two goals.

Method

Employee survey at the urban administration of Dortmund, Germany, about presenteeism with symptoms of an acute respiratory infection and the willingness to report to work during an influenza pandemic.

Results

Results of multivariate linear regression indicated: There is only little association between propensity for presenteeism with symptoms of an acute respiratory infection and willingness to report to work during an influenza pandemic (R²?=?0,024).

Conclusion

Results did not support the aforementioned conflict of goals between reducing presenteeism with symptoms of an acute respiratory infection and promoting willingness to report to work during an influenza pandemic. Further research should investigate interventions, which will support both goals alike, in order to support pandemic planning.