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1.  Complications and Intercenter Variability of Three-Column Resection Osteotomies for Spinal Deformity Surgery: A Retrospective Review of 423 Patients 
Study Type Retrospective review of a prospectively collected multicenter database.
Introduction Three-column resection osteotomies (3CO), including pedicle subtraction osteotomies and vertebral column resections are performed for correction of sagittal deformity; however, they have high rates of reported complications. This study examined the incidence and intercenter variability of major intraoperative complications (IOC), postoperative complications (POC), and overall complications (IOC + POC) up to 6 weeks postoperation.
Objective The aim of the study is to examine the incidence and intercenter variability of major complications associated with 3CO.
Patients and Methods A retrospective review of patients with 3CO from eight different sites was performed. The incidence and types of complications were determined for the study population (N = 423). The analysis compared patients with one (n = 391) and two (n = 32) osteotomies, as well as patients with a thoracic osteotomy (ThO) (n = 72) versus a lumbosacral osteotomy (LSO) (n = 319) of the spine. Subsequent analysis was performed to compare sites with low-osteotomy volumes (< 50 patients) to sites with large osteotomy volumes (more than 50 patients). Major blood loss (MBL) was defined as more than 4L.
Results Of the 423 patients, the incidence of major IOC, POC, and overall complications was 28, 45, and 58%, respectively (Table 1). The most common major IOC was MBL (24%) and the most common POC was unplanned return to the operating room (OR) (19%). Other IOC included cord deficit (2.6%), pneumothorax (1.5%), large vessel injury (1.7%), nerve root injury (1.4%), and cardiac arrest (0.2%). Other POC included motor deficit (12.1%), deep infection (7.6%), acute respiratory distress/failure (4.7%), deep venous thrombosis (3.1%), pulmonary embolism (2.8%), arrhythmia (1.2%), reintubation and sepsis (0.7%), cauda equine syndrome, myocardial infarction, visual deficit, stroke (0.5%), and death (0.2%). Patients with one 3CO had significantly less POC (43 vs. 69%, p < 0.01) and overall complications (57 vs. 75%, p < 0.01) than patients with two 3CO (Fig. 1). IOC, MBL, and return to the OR were not significantly different between groups. Patients with ThO had significantly more POC (66 vs. 39%, p < 0.01) and overall complications (76 vs. 53%, p < 0.001) than patients with LSO. Patients with LSO had more MBL (25 vs. 14%, p = 0.04). Patients with ThO had more unplanned return to OR (41 vs. 14%, p < 0.001) (Fig. 2). The incidence of IOC was greater for the low-volume sites than high-volume sites (46 vs. 23%, p < 0.001). Low-volume sites had a higher frequency of patients with MBL than high-volume sites (45 vs. 18%, p < 0.001) (Fig. 3). Patients who experienced MBL had a significantly longer operating time (p < 0.001) and a higher risk of developing other IOC, POC, and overall complications (OR = 2.18, 1.51, 1.63, respectively) than patients who did not experience substantial blood loss.
Conclusions The overall incidence of complications was 58% following 3CO surgery. There was significant variation in incidence of complications depending on the number, location, and experience of performing osteotomies. Risks for developing complications included having two osteotomies, ThO, surgery at a low-volume center, and blood loss more than 4 L. With a better understanding of 3CO complications and risk factors, physicians may be more informed in the decision-making process of sagittal plane deformity correction.
PMCID: PMC3836886  PMID: 24436716
three-column osteotomy; pedicle subtraction osteotomy; vertebral column resection; complications; intercenter variability
2.  The impact of a corrective tether on a scoliosis porcine model: a detailed 3D analysis with a 20 weeks follow-up 
European Spine Journal  2013;22(8):1800-1809.
Non-fusion treatment for adolescent idiopathic scoliosis generates interest due to the potential for growth preservation and mobility. Using an established porcine scoliotic model, this study aims to evaluate the global alignment and the morphology of the spine with and without application of a non-fusion corrective tether.
At 12 weeks of age, 21 immature Yorkshire pigs had an induction of scoliosis. Once a 50° Cobb angle was obtained; animals were placed into one of the following groups: a scoliosis model group (SM, n = 11) where animals were euthanized, tether release group (TR, n = 5) where the inducing tether was removed, and an anterior correction group (AC, n = 5) where the inducing tether was removed and non-fusion corrective tether was applied. TR and AC were observed for a further 20 weeks and then euthanized. Post-mortem CT scans were used to create 3D spinal reconstructions to obtain global and morphologic parameters.
Maximal Cobb angle of the scoliotic deformity was significantly lower for AC (27.9° ± 12.0°) than for the two other groups (TR 52.7° ± 10.0°, SM 48.3° ± 7.6°). AC experienced an increase in kyphosis (24.2° ± 15.9°) compared to TR (7.1° ± 6.4°). Correction in the axial plane was also observed in AC versus TR. Correction of vertebral wedging was found for AC compared to SM and TR in the three apical vertebrae.
3D realignment of scoliotic curves was observed with application of the corrective tether. The correction was the product of both mechanical action and growth modulation. These findings are encouraging for future development of a non-fusion device for the treatment of immature scoliotic curves.
PMCID: PMC3731486  PMID: 23503934
Scoliosis model; Non-fusion correction; Growth modulation; Growth preservation
3.  Partial Facetectomy for Lumbar Foraminal Stenosis 
Advances in Orthopedics  2014;2014:534658.
Background. Several different techniques exist to address the pain and disability caused by isolated nerve root impingement. Failure to adequately decompress the lumbar foramen may lead to failed back surgery syndrome. However, aggressive treatment often causes spinal instability or may require fusion for satisfactory results. We describe a novel technique for decompression of the lumbar nerve root and demonstrate its effectiveness in relief of radicular symptoms. Methods. Partial facetectomy was performed by removal of the medial portion of the superior facet in patients with lumbar foraminal stenosis. 47 patients underwent the procedure from 2001 to 2010. Those who demonstrated neurogenic claudication without spinal instability or central canal stenosis and failed conservative management were eligible for the procedure. Functional level was recorded for each patient. These patients were followed for an average of 3.9 years to evaluate outcomes. Results. 27 of 47 patients (57%) reported no back pain and no functional limitations. Eight of 47 patients (17%) reported moderate pain, but had no limitations. Six of 47 patients (13%) continued to experience degenerative symptoms. Five of 47 patients (11%) required additional surgery. Conclusions. Partial facetectomy is an effective means to decompress the lumbar nerve root foramen without causing spinal instability.
PMCID: PMC4119622  PMID: 25110591
4.  Mortality and molecular epidemiology associated with extended-spectrum β-lactamase production in Escherichia coli from bloodstream infection 
The rate of infections due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is growing worldwide. These infections are suspected to be related to increased mortality. We aimed to estimate the difference in mortality due to bloodstream infections (BSIs) with ESBL-positive and ESBL-negative E. coli isolates and to determine the molecular epidemiology of our ESBL-positive isolates.
Materials and methods
We performed a cohort study on consecutive patients with E. coli BSI between 2008 and 2010 at the Charité University Hospital. Collected data were ESBL production, basic demographic parameters, and underlying diseases by the Charlson comorbidity index (CCI). The presence of ESBL genes was analyzed by polymerase chain reaction (PCR) and sequencing. Phylogenetic groups of ESBL-positive E. coli were determined by PCR. Risk factors for mortality were analyzed by multivariable regression analysis.
We identified 115 patients with BSI due to E. coli with ESBL phenotype and 983 due to ESBL-negative E. coli. Fifty-eight percent (n=67) of the ESBL-positive BSIs were hospital-acquired. Among the 99 isolates that were available for PCR screening and sequencing, we found mainly 87 CTX-M producers, with CTX-M-15 (n=55) and CTX-M-1 (n=21) as the most common types. Parameters significantly associated with mortality were age, CCI, and length of stay before and after onset of BSI.
The most common ESBL genotypes in clinical isolates from E. coli BSIs were CTX-M-15 (58%) and CTX-M-1 (22%). ESBL production in clinical E. coli BSI isolates was not related to increased mortality. However, the common occurrence of hospital-acquired BSI due to ESBL-positive E. coli indicates future challenges for hospitals.
PMCID: PMC3958498  PMID: 24648746
BSI; mortality; ESBL-genotype; sepsis
5.  The Warmer the Weather, the More Gram-Negative Bacteria - Impact of Temperature on Clinical Isolates in Intensive Care Units 
PLoS ONE  2014;9(3):e91105.
We investigated the relationship between average monthly temperature and the most common clinical pathogens causing infections in intensive care patients.
A prospective unit-based study in 73 German intensive care units located in 41 different hospitals and 31 different cities with total 188,949 pathogen isolates (102,377 Gram-positives and 86,572 Gram-negatives) from 2001 to 2012. We estimated the relationship between the number of clinical pathogens per month and the average temperature in the month of isolation and in the month prior to isolation while adjusting for confounders and long-term trends using time series analysis. Adjusted incidence rate ratios for temperature parameters were estimated based on generalized estimating equation models which account for clustering effects.
The incidence density of Gram-negative pathogens was 15% (IRR 1.15, 95%CI 1.10–1.21) higher at temperatures ≥20°C than at temperatures below 5°C. E. cloacae occurred 43% (IRR = 1.43; 95%CI 1.31–1.56) more frequently at high temperatures, A. baumannii 37% (IRR = 1.37; 95%CI 1.11–1.69), S. maltophilia 32% (IRR = 1.32; 95%CI 1.12–1.57), K. pneumoniae 26% (IRR = 1.26; 95%CI 1.13–1.39), Citrobacter spp. 19% (IRR = 1.19; 95%CI 0.99–1.44) and coagulase-negative staphylococci 13% (IRR = 1.13; 95%CI 1.04–1.22). By contrast, S. pneumoniae 35% (IRR = 0.65; 95%CI 0.50–0.84) less frequently isolated at high temperatures. For each 5°C increase, we observed a 3% (IRR = 1.03; 95%CI 1.02–1.04) increase of Gram-negative pathogens. This increase was highest for A. baumannii with 8% (IRR = 1.08; 95%CI 1.05–1.12) followed by K. pneumoniae, Citrobacter spp. and E. cloacae with 7%.
Clinical pathogens vary by incidence density with temperature. Significant higher incidence densities of Gram-negative pathogens were observed during summer whereas S. pneumoniae peaked in winter. There is increasing evidence that different seasonality due to physiologic changes underlies host susceptibility to different bacterial pathogens. Even if the underlying mechanisms are not yet clear, the temperature-dependent seasonality of pathogens has implications for infection control and study design.
PMCID: PMC3944990  PMID: 24599500
6.  Surgical Treatment for Adult Spinal Deformity: Projected Cost Effectiveness at 5-Year Follow-Up 
The Ochsner Journal  2014;14(1):14-22.
In the United States, expenditures related to spine care are estimated to account for $86 billion annually. Policy makers have set a cost-effectiveness benchmark of less than $100,000/quality adjusted life year (QALY), forcing surgeons to defend their choices economically. This study projects the cost/QALY for surgical treatment of adult spinal deformity at 5-year follow-up based on 2-year cost- and health-related quality-of-life (HRQOL) data.
In a review of 541 patients with adult spinal deformity, the patients who underwent revision or were likely to undergo revision were identified and cost of surgery was doubled to account for the second procedure; all other patients maintained the cost of the initial surgery. Oswestry Disability Index (ODI) was modeled by revision status based on literature findings. Total surgical cost was based on Medicare reimbursement. Chi square and student t tests were utilized to compare cost-effective and non–cost-effective patients.
The average cost/QALY at 5-year follow-up was $120,311.73. A total of 40.7% of patients fell under the threshold of a cost/QALY <$100,000. Cost-effective patients had higher baseline ODI scores (45% vs 34% [P=0.001]), lower baseline total Scoliosis Research Society scores (2.89 vs 3.00 [P=0.04]), and shorter fusions (8.23 vs 9.87 [P=0.0001]).
We found 40.7% of patients to be below the threshold of cost effectiveness. Factors associated with reaching the threshold <$100,000/QALY were greater preoperative disability, diagnosis of idiopathic scoliosis, poor preoperative HRQOL scores, and fewer fusion levels.
PMCID: PMC3962303  PMID: 24688328
Cost-benefit analysis; quality adjusted life years; quality of life; scoliosis; spine; surgical procedures–operative
7.  Likelihood of Reaching Minimal Clinically Important Difference in Adult Spinal Deformity: A Comparison of Operative and Nonoperative Treatment 
The Ochsner Journal  2014;14(1):67-77.
Few studies have examined threshold improvements in health-related quality of life (HRQOL) by measuring minimal clinically important differences (MCIDs) in treatment of adult spinal deformity. We hypothesized that patients undergoing operative treatment would be more likely to achieve MCID threshold improvement compared with those receiving nonoperative care, although a subset of nonoperative patients may still reach threshold.
We analyzed a multicenter, prospective, consecutive case series of 464 patients: 225 nonoperative and 239 operative. To be included in the study, patients had to have adult spinal deformity, be older than 18 years, and have both baseline and 1-year follow-up HRQOL measures (Oswestry Disability Index [ODI], Short Form-36 [SF-36] health survey, and Scoliosis Research Society-22 [SRS-22] questionnaire). We compared the percentages of patients achieving established MCID thresholds between operative and nonoperative groups using risk ratios (RR) with a 95% confidence interval (CI).
Compared to nonoperative patients, surgical patients demonstrated significant mean improvement (P<0.01) and were more likely to achieve threshold MCID improvement across all HRQOL scores (ODI RR = 7.37 [CI 4.45, 12.21], SF-36 physical component score RR = 2.96 [CI 2.11, 4.15], SRS Activity RR = 3.16 [CI 2.32, 4.31]). Furthermore, operative patients were more likely to reach threshold MCID improvement in 2 or more HRQOL measures simultaneously and were less likely to deteriorate.
Patients in both the operative and nonoperative treatment groups demonstrated improvement in at least one HRQOL measure at 1 year. However, surgical treatment was more likely to result in threshold improvement and more likely to lead to simultaneous improvement across multiple measures of ODI, SF-36, and SRS-22. Although a subset of nonoperative patients achieved threshold improvement, nonoperative patients were significantly less likely to improve in multiple HRQOL measures and more likely to sustain MCID deterioration or no change.
PMCID: PMC3963055  PMID: 24688336
Disability evaluation; pain management; quality of life; spinal cord diseases; surgical procedures–operative
8.  Clinical and radiographic parameters that distinguish between the best and worst outcomes of scoliosis surgery for adults 
European Spine Journal  2012;22(2):402-410.
Predictors of marked improvement versus failure to improve following surgery for adult scoliosis have not been identified. Our objective was to identify factors that distinguish between patients with the best and worst outcomes following surgery for adult scoliosis.
This is a secondary analysis of a prospective, multicenter spinal deformity database. Inclusion criteria included: age 18–85, scoliosis (Cobb ≥ 30°), and 2-year follow-up. Based on the Oswestry Disability Index (ODI) and the SRS-22 at 2-year follow-up, patients with the best and worst outcomes were identified for younger (18–45) and older (46–85) adults with scoliosis. Clinical and radiographic factors were compared between patients with the best and worst outcomes.
276 patients met inclusion criteria (89 younger and 187 older patients). Among younger patients, predictors of poor outcome included: depression/anxiety, smoking, narcotic medication use, older age, greater body mass index (BMI) and greater severity of pain prior to surgery. Among older patients, predictors of poor outcome included: depression/anxiety, narcotic medication use, greater BMI and greater severity of pain prior to surgery. None of the other baseline or peri-operative factors assessed distinguished the best and worst outcomes for younger or older patients, including severity of deformity, operative parameters, or the occurrence of complications.
Not all patients achieve favorable outcomes following surgery for adult scoliosis. Baseline and peri-operative factors distinguishing between patients with the best and worst outcomes were predominantly patient factors, including BMI, depression/anxiety, smoking, and pain severity; not comorbidities, severity of deformity, operative parameters, or complications.
PMCID: PMC3555616  PMID: 23073746
Adult scoliosis; Outcomes; Surgery; Disability; Age; Depression; Obesity; Smoking
9.  Risk factors for major peri-operative complications in adult spinal deformity surgery: a multi-center review of 953 consecutive patients 
European Spine Journal  2012;21(12):2603-2610.
Major peri-operative complications for adult spinal deformity (ASD) surgery remain common. However, risk factors have not been clearly defined. Our objective was to identify patient and surgical parameters that correlate with the development of major peri-operative complications with ASD surgery.
This is a multi-center, retrospective, consecutive, case–control series of surgically treated ASD patients. All patients undergoing surgical treatment for ASD at eight centers were retrospectively reviewed. Each center identified 10 patients with major peri-operative complications. Randomization tables were used to select a comparably sized control group of patients operated during the same time period that they did not suffer major complications. The two groups were analyzed for differences in clinical and surgical factors. Analysis was restricted to non-instrumentation related complications.
At least one major complication occurred in 80 of 953 patients (8.4 %), including 72 patients with non-instrumentation related complications. There were no significant differences between the complications and control groups based on the demographics, ASA grade, co-morbidities, body mass index, prior surgeries, pre-operative anemia, smoking, operative time or ICU stay (p > 0.05). Hospital stay was significantly longer for the complications group (14.4 vs. 7.9 days, p = 0.001). The complications group had higher percentages of staged procedures (46 vs. 37 %, p = 0.011) and combined anterior–posterior approaches (56 vs. 32 %, p = 0.011) compared with the control group.
The major peri-operative complication rate was 8.4 % for 953 surgically treated ASD patients. Significantly higher rates of complications were associated with staged and combined anterior–posterior surgeries. None of the patient factors assessed were significantly associated with the occurrence of major peri-operative complications. Improved understanding of risk profiles and procedure-related parameters may be useful for patient counseling and efforts to reduce complication rates.
PMCID: PMC3508213  PMID: 22592883
Complications; Surgery; Adult; Spinal deformity; Risk factor
10.  Risk Factors Associated with the Community-Acquired Colonization of Extended-Spectrum Beta-Lactamase (ESBL) Positive Escherichia Coli. An Exploratory Case-Control Study 
PLoS ONE  2013;8(9):e74323.
The number of extended-spectrum beta-lactamase (ESBL) positive (+) Escherichia coli is increasing worldwide. In contrast with many other multidrug-resistant bacteria, it is suspected that they predominantly spread within the community. The objective of this study was to assess factors associated with community-acquired colonization of ESBL (+) E. coli.
We performed a matched case-control study at the Charité University Hospital Berlin between May 2011 and January 2012. Cases were defined as patients colonized with community-acquired ESBL (+) E. coli identified <72 h after hospital admission. Controls were patients that carried no ESBL-positive bacteria but an ESBL-negative E.coli identified <72 h after hospital admission. Two controls per case were chosen from potential controls according to admission date. Case and control patients completed a questionnaire assessing nutritional habits, travel habits, household situation and language most commonly spoken at home (mother tongue). An additional rectal swab was obtained together with the questionnaire to verify colonization status. Genotypes of ESBL (+) E. coli strains were determined by PCR and sequencing. Risk factors associated with ESBL (+) E. coli colonization were analyzed by a multivariable conditional logistic regression analysis.
We analyzed 85 cases and 170 controls, respectively. In the multivariable analysis, speaking an Asian language most commonly at home (OR = 13.4, CI 95% 3.3–53.8; p<0.001) and frequently eating pork (≥3 meals per week) showed to be independently associated with ESBL colonization (OR = 3.5, CI 95% 1.8–6.6; p<0.001). The most common ESBL genotypes were CTX-M-1 with 44% (n = 37), CTX-M-15 with 28% (n = 24) and CTX-M-14 with 13% (n = 11).
An Asian mother tongue and frequently consuming certain types of meat like pork can be independently associated with the colonization of ESBL-positive bacteria. We found neither frequent consumption of poultry nor previous use of antibiotics to be associated with ESBL colonization.
PMCID: PMC3770595  PMID: 24040229
11.  The impact of staffing on central venous catheter-associated bloodstream infections in preterm neonates – results of nation-wide cohort study in Germany 
Very low birthweight (VLBW) newborns on neonatal intensive care units (NICU) are at increased risk for developing central venous catheter-associated bloodstream infections (CVC BSI). In addition to the established intrinsic risk factors of VLBW newborns, it is still not clear which process and structure parameters within NICUs influence the prevalence of CVC BSI.
The study population consisted of VLBW newborns from NICUs that participated in the German nosocomial infection surveillance system for preterm infants (NEO-KISS) from January 2008 to June 2009. Structure and process parameters of NICUs were obtained by a questionnaire-based enquiry. Patient based date and the occurrence of BSI derived from the NEO-KISS database. The association between the requested parameters and the occurrance of CVC BSI and laboratory-confirmed BSI was analyzed by generalized estimating equations.
We analyzed data on 5,586 VLBW infants from 108 NICUs and found 954 BSI cases in 847 infants. Of all BSI cases, 414 (43%) were CVC-associated. The pooled incidence density of CVC BSI was 8.3 per 1,000 CVC days. The pooled CVC utilization ratio was 24.3 CVC-days per 100 patient days. A low realized staffing rate lead to an increased risk of CVC BSI (OR 1.47; p=0.008) and also of laboratory-confirmed CVC BSI (OR 1.78; p=0.028).
Our findings show that low levels of realized staffing are associated with increased rates of CVC BSI on NICUs. Further studies are necessary to determine a threshold that should not be undercut.
PMCID: PMC3643825  PMID: 23557510
Staffing; CVC; BSI; NICU; VLBW
12.  Sagittal spino-pelvic alignment failures following three column thoracic osteotomy for adult spinal deformity 
European Spine Journal  2011;21(4):698-704.
Three column thoracic osteotomy (TCTO) is effective to correct rigid thoracic deformities, however, reasons for residual postoperative spinal deformity are poorly defined. Our objective was to evaluate risk factors for poor spino-pelvic alignment (SPA) following TCTO for adult spinal deformity (ASD).
Multicenter, retrospective radiographic analysis of ASD patients treated with TCTO. Radiographic measures included: correction at the osteotomy site, thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic tilt (PT), and pelvic incidence (PI). Final SVA and PT were assessed to determine if ideal SPA (SVA < 4 cm, PT < 25°) was achieved. Differences between the ideal (IDEAL) and failed (FAIL) SPA groups were evaluated.
A total of 41 consecutive ASD patients treated with TCTO were evaluated. TCTO significantly decreased TK, maximum coronal Cobb angle, SVA and PT (P < 0.05). Ideal SPA was achieved in 32 (78%) and failed in 9 (22%) patients. The IDEAL and FAIL groups had similar total fusion levels and similar focal, SVA and PT correction (P > 0.05). FAIL group had larger pre- and post-operative SVA, PT and PI and a smaller LL than IDEAL (P < 0.05).
Poor SPA occurred in 22% of TCTO patients despite similar operative procedures and deformity correction as patients in the IDEAL group. Greater pre-operative PT and SVA predicted failed post-operative SPA. Alternative or additional correction procedures should be considered when planning TCTO for patients with large sagittal global malalignment, otherwise patients are at risk for suboptimal correction and poor outcomes.
PMCID: PMC3326123  PMID: 21837411
Spinopelvic alignment; Sagittal vertical axis; Osteotomy; Pedicle subtraction osteotomy; Thoracic; Vertebral column resection
13.  Sacro-femoral-pubic angle: a coronal parameter to estimate pelvic tilt 
European Spine Journal  2011;21(4):719-724.
Pelvic tilt is an established measure of position which has been tied to sagittal plane spinal deformity. Increased tilt is noted in the setting of the aging spine and sagittal malalignment syndromes such as flatback (compensatory mechanism). However, the femoral heads are often poorly visualized on sagittal films of scoliosis series in adults, limiting the ability to determine pelvic incidence and tilt. There is a need to establish a coronal plane (better visualization) pelvic parameter which correlates closely with pelvic tilt.
This is a retrospective review of 71 adult patients (47 females and 24 males) with full-length standing spine radiographs. Visualization of all spinal and pelvic landmarks was available coronally and sagittally (including pelvis and acetabuli). Pelvic tilt was calculated through validated digital analysis software (SpineView®). A new parameter, the sacro-femoral-pubic angle (midpoint of S1 endplate to centroid of acetabuli to superior border of the pubic symphysis) was analyzed for correlation (and predictive ability) with sagittal pelvic tilt.
The sacro-femoral-pubic angle (SFP angle) was highly correlated to PT, and according to this analysis, pelvic tilt could be estimated by the formula: PT = 75 − (SFP angle). A Pearson’s correlation coefficient of 0.74 (p < 0.005) and predictive ability of 76% accuracy was obtained (±7.5°). The correlation and predictive ability was greater for males compared to females (male: r = 0.87 and predictive model = 93%; female: r = 0.67 and predictive model = 67%).
The pelvic tilt is an essential measure in the context of radiographic evaluation of spinal deformity and malalignment. Given the routinely excellent visibility of coronal films this study established the SFP as a coronal parameter which can reliably estimate pelvic tilt. The high correlation and predictive ability of the SFP angle should prompt further study and clinical application when lateral radiographs do not permit assessment of pelvic parameters.
PMCID: PMC3326127  PMID: 22113529
Sagittal alignment; Pelvic tilt; Spine; Coronal; Radiographic evaluation
14.  Health care workers causing large nosocomial outbreaks: a systematic review 
Staff in the hospital itself may be the source of a nosocomial outbreak (NO). But the role of undetected carriers as an outbreak source is yet unknown.
A systematic review was conducted to evaluate outbreaks caused by health care workers (HCW). The Worldwide Outbreak Database and PubMed served as primary sources of data. Articles in English, German or French were included. Other reviews were excluded. There were no restrictions with respect to the date of publication.
Data on setting, pathogens, route of transmission, and characteristics of the HCW was retrieved. Data from large outbreaks were compared to smaller outbreaks.
152 outbreaks were included, mainly from surgery, neonatology, and gynecology departments. Most frequent corresponding infections were surgical site infections, infection by hepatitis B virus, and septicemia. Hepatitis B virus (27 NO), S. aureus (49 NO) and S. pyogenes (19 NO) were the predominant pathogens involved. 59 outbreaks (41.5%) derived from physicians and 56 outbreaks (39.4%) derived from nurses. Transmission mainly occurred via direct contact. Surgical and pediatric departments were significantly associated with smaller outbreaks, and gynecology with larger outbreaks. Awareness of carrier status significantly decreased the risk of causing large outbreaks.
As NO caused by HCW represent a rare event, screening of personnel should not be performed regularly. However, if certain species of microorganisms are involved, the possibility of a carrier should be taken into account.
PMCID: PMC3599984  PMID: 23432927
Nosocomial outbreak; Staff; Personnel; Health care workers; Health care associated infection
16.  The step from a voluntary to a mandatory national nosocomial infection surveillance system: the influence on infection rates and surveillance effect 
The German national nosocomial infection surveillance system, KISS, has a component for very low birth weight (VLBW) infants (called NEO-KISS) which changed from a system with voluntary participation and confidential data feedback to a system with mandatory participation and confidential feedback.
In order to compare voluntary and mandatory surveillance data, two groups were defined by the surveillance start date. Neonatal intensive care unit (NICU) parameters and infection rates of the NICUs in both groups were compared. In order to analyze the surveillance effect on primary bloodstream infection rates (BSI), all VLBW infants within the first three years of participation in both groups were considered. The adjusted effect measures for the year of participation were calculated.
An increase from 49 NICUs participating in 2005 to 152 in 2006 was observed after the introduction of mandatory participation. A total of 4280 VLBW infants was included in this analysis. Healthcare-associated incidence densities rates were similar in both groups. Using multivariate analysis with the endpoint primary BSI rate and comparing the first and third year of participation lead to an adjusted incidence rate ratio (IRR) of 0.78 (CI95 0.66-0.93) for old (voluntary) and 0.81 (CI95 0.68-0.97) for new (mandatory) participants.
The step from a voluntary to a mandatory HCAI surveillance system alone may lead to substantial improvements on a countrywide scale.
PMCID: PMC3489557  PMID: 22958509
Surveillance; Nosocomial infections; Neonatal intensive care unit; Bloodstream infection
17.  Does Removing the Spinal Tether in a Porcine Scoliosis Model Result in Persistent Deformity?: A Pilot Study 
Using a tethering technique, a porcine model of scoliosis has been created. Ideally, tether release before placement and evaluation of corrective therapies would lead to persistent scoliosis.
Does release of the spinal tether result in persistent deformity?
Using a unilateral spinal tether and ipsilateral rib cage tethering, scoliosis was initiated on seven pigs. The spinal tether was released after progression to a Cobb angle of 50°. Biweekly radiographs were taken for 18 weeks after tether release to evaluate longitudinal changes in coronal and sagittal Cobb angles. Postmortem fine-cut CT scans were used to evaluate vertebral and disc wedging and axial rotation; results were compared to a previously published data set of 11 animals euthanized before release of the tether (control group).
Radiographic analysis demonstrated two responses to tether release: a persistent deformity group and an autocorrective group. Differences between these two groups included number of days with the tether in place before reaching a Cobb angle of 50° and degree of deformity immediately after scoliosis induction. CT analysis of the tether release versus tether intact groups demonstrated progression in vertebral body wedging without differences in apical rotation.
With the appropriate inducing parameters, release of the spinal tether does not systematically result in deformity correction. Tether release resulted in a reduction in Cobb angle in the first several weeks followed by steady curve progression. Deformity progression was confirmed using detailed CT morphometric analysis.
Clinical Relevance
The tether release model will be used to evaluate corrective nonfusion technologies in future investigations.
PMCID: PMC3069295  PMID: 21210315
18.  Individual units rather than entire hospital as the basis for improvement: the example of two Methicillin resistant Staphylococcus aureus cohort studies 
Two MRSA surveillance components exist within the German national nosocomial infection surveillance system KISS: one for the whole hospital (i.e. only hospital based data and no rates for individual units) and one for ICU-based data (rates for each individual ICU). The objective of this study was to analyze which surveillance system (a hospital based or a unit based) leads to a greater decrease in incidence density of nosocomial MRSA
Two cohort studies of surveillance data were used: Data from a total of 224 hospitals and 359 ICUs in the period from 2004 to 2009. Development over time was described first for both surveillance systems. In a second step only data were analyzed from those hospitals/ICUs with continuous participation for at least four years. Incidence rate ratios (IRR) with 95% confidence intervals were calculated to compare incidence densities between different time intervals.
In the baseline year the mean MRSA incidence density of hospital acquired MRSA cases was 0.25 and the mean incidence density of ICU-acquired MRSA was 1.25 per 1000 patient days. No decrease in hospital-acquired MRSA rates was found in a total of 111 hospitals with continuous participation in the hospital- based system. However, in 159 ICUs with continuous participation in the unit-based system, a significant decrease of 29% in ICU-acquired MRSA was identified.
A unit-based approach of surveillance and feedback seems to be more successful in decreasing nosocomial MRSA rates, compared to a hospital-based approach. Therefore each surveillance system should provide unit-based data to stimulate activities on the unit level.
PMCID: PMC3436609  PMID: 22958320
Infection prevention; Surveillance; MRSA; Quality management
19.  Decreasing healthcare-associated infections (HAI) is an efficient method to decrease healthcare-associated Methicillin-resistant S.aureus (MRSA) infections Antimicrobial resistance data from the German national nosocomial surveillance system KISS 
By analysing the data of the intensive care unit (ICU) component of the German national nosocomial infection surveillance system (KISS) during the last ten years, we have observed a steady increase in the MRSA rates (proportions) from 2001 to 2005 and only a slight decrease from 2006 to 2010. The objective of this study was to investigate the development of the incidence density of nosocomial MRSA infections because this is the crucial outcome for patients.
Data from 103 ICUs with ongoing participation during the observation period were included. The pooled incidence density of nosocomial MRSA infections decreased significantly from 0.37 per 1000 patient days in 2001 to 0.15 per 1000 patient days in 2010 (RR = 0.40; CI95 0.29-0.55). This decrease was proportional to the significant decrease of all HCAI during the same time period (RR = 0.61; CI95 0.58-0.65).
The results underline the need to concentrate infection control activities on measures to control HCAI in general rather than focusing too much on specific MRSA prevention measures. MRSA rates (proportions) are not a very useful indicator of the situation.
PMCID: PMC3415117  PMID: 22958746
Surveillance; MRSA; epidemiology; Staphylococcus aureus
20.  Screening and control of methicillin-resistant Staphylococcus aureus in 186 intensive care units: different situations and individual solutions 
Critical Care  2011;15(6):R285.
Controversy exists about the benefit of screening for prevention of methicillin-resistant Staphylococcus aureus (MRSA) in intensive care units (ICUs) and recent studies have shown conflicting results. The aim of this observational study was to describe and evaluate the association between MRSA incidence densities (IDs) and screening and control measures in ICUs participating in the German Nosocomial Infection Surveillance System.
The surveillance module for multidrug-resistant bacteria collects data on MRSA cases in ICUs with the aim to provide a national reference and a tool for evaluation of infection control management. The median IDs of MRSA cases per 1000 patient-days (pd) with the interquartile range (IQR) were calculated from the pooled data of 186 ICUs and correlated with parameters derived from a detailed questionnaire regarding ICU structure, microbiological diagnostics and MRSA screening and control measures. The association between questionnaire results and MRSA cases was evaluated by generalized linear regression models.
One hundred eighty-six ICUs submitted data on MRSA cases for 2007 and 2008 and completed the questionnaire. During the period of analysis, 4935 MRSA cases occurred in these ICUs; of these, 3928 (79.6%) were imported and 1007 MRSA cases (20.4%) were ICU-acquired. Median MRSA IDs were 3.23 (IQR 1.24-5.73), 2.24 (IQR 0.63-4.30) and 0.64 (IQR 0.17-1.39) per 1000 pd for all cases, imported and ICU-acquired MRSA cases, respectively. MRSA IDs as well as implemented MRSA screening and control measures varied widely between ICUs. ICUs performing universal admission screening had significantly higher MRSA IDs than ICUs performing targeted or no screening. Separate regression models for ICUs with different screening strategies included the incidence of imported MRSA cases, the type of ICU, and the length of stay in independent association with the number of ICU-acquired MRSA cases.
The analysis shows that MRSA IDs and structural parameters differ considerably between ICUs. In response, ICUs have combined screening and control measures in many ways to achieve various individual solutions. The incidence of imported MRSA cases might be helpful for consideration in the planning of MRSA control programmes.
PMCID: PMC3388634  PMID: 22118016
21.  Acute Reciprocal Changes Distant from the Site of Spinal Osteotomies Affect Global Postoperative Alignment 
Advances in Orthopedics  2011;2011:415946.
Introduction. Three-column vertebral resections are frequently applied to correct sagittal malalignment; their effects on distant unfused levels need to be understood. Methods. 134 consecutive adult PSO patients were included (29 thoracic, 105 lumbar). Radiographic analysis included pre- and postoperative regional curvatures and pelvic parameters, with paired independent t-tests to evaluate changes. Results. A thoracic osteotomy with limited fusion leads to a correction of the kyphosis and to a spontaneous decrease of the unfused lumbar lordosis (−8°). When the fusion was extended, the lumbar lordosis increased (+8°). A lumbar osteotomy with limited fusion leads to a correction of the lumbar lordosis and to a spontaneous increase of the unfused thoracic kyphosis (+13°). When the fusion was extended, the thoracic kyphosis increased by 6°. Conclusion. Data from this study suggest that lumbar and thoracic resection leads to reciprocal changes in unfused segments and requires consideration beyond focal corrections.
PMCID: PMC3189460  PMID: 22007318
22.  Nosocomial methicillin resistant Staphylococcus aureus pneumonia - epidemiology and trends based on data of a network of 586 German ICUs (2005-2009) 
The epidemiology of MRSA pneumonia varies across countries. One of the most import risk factors for the development of nosocomial MRSA pneumonia is mechanical ventilation. Methicillin resistance in S. aureus ventilator associated pneumonia (VAP) ranged between 37% in German, 54% in the US American and 78% in Asian and Latin American ICUs. In 2009, the incidence density of nosocomial VAP caused by MRSA was 0.28 per 1000 ventilation days in a network of 586 German ICUs. Incidences peaked in neurological and neurosurgical ICUs. Crude hospital mortality in studies performed after 2005 lay between 27% and 59% and attributable MRSA pneumonia mortality at 40%. Since 2005, US American and German data indicate decreasing trends for MRSA pneumonia. Measures to reduce MRSA pneumonia or to control the spread of MRSA include hand hygiene, standard and contact precautions, oral contamination with chlor hexidine, skin decontamination with antiseptics, screening, and (possibly) patient isolation in a single room.
PMCID: PMC3352100  PMID: 21163726
methicillin resistant Staphylococcus aureus; pneumonia; nosocomial; mortality; risk factor; age; change over time
23.  Nosocomial infection in small for gestational age newborns with birth weight <1500 g: a multicentre analysis 
To investigate whether preterm newborns who are small for gestational age are at increased risk of nosocomial infections and necrotising enterocolitis.
Design, setting and subjects
The German national surveillance system for nosocomial infection in very low birthweight infants uses the US Centers for Disease Control and Prevention criteria. 2918 newborns (24–28 weeks), born between 2000 and 2004, were selected after application of predefined inclusion criteria to ensure similar proportions of small and appropriate weight for gestational age newborns across gestational age groups.
Main outcome measures
The outcome criterion was at least one episode of nosocomial sepsis, pneumonia or necrotising enterocolitis. Adjusted odds ratios and corresponding 95% CIs were calculated based on general estimating equation models.
The study population consisted of 13% (n = 392) small and 87% (n = 2526) appropriate weight for gestational age infants. 33% (n = 950) of the infants experienced at least one episode of sepsis: 42% (n = 163) of small and 31% (n = 787) of appropriate weight for gestational age newborns (adjusted OR 1.41, 95% CI 1.05 to 1.89). Pneumonia was diagnosed in 6% (n = 171) of infants: 8.4% (n = 33) of small and 5.5% (n = 138) of appropriate weight for gestational age newborns (adjusted OR 1.57, 95% CI 1.19 to 5.57). Necrotising enterocolitis was documented in 5.2% (n = 152) of infants: 7.1% (n = 28) of small and 4.9% of (n = 124) appropriate weight for gestational age newborns (adjusted OR 1.20, 95% confidence interval 0.75 to 1.94).
Growth‐retarded preterm infants seem to be at increased risk of nosocomial infection, irrespective of the responsible pathogen. Future immunological research should elucidate potential causal associations.
PMCID: PMC2675389  PMID: 17460021
24.  Dramatic increase of third-generation cephalosporin-resistant E. coli in German intensive care units: secular trends in antibiotic drug use and bacterial resistance, 2001 to 2008 
Critical Care  2010;14(3):R113.
The objective of the present study was to analyse secular trends in antibiotic consumption and resistance data from a network of 53 intensive care units (ICUs).
The study involved prospective unit and laboratory-based surveillance in 53 German ICUs from 2001 through 2008. Data were calculated on the basis of proportions of nonduplicate resistant isolates, resistance densities (that is, the number of resistant isolates of a species per 1,000 patient-days) and an antimicrobial usage density (AD) expressed as daily defined doses (DDD) and normalised per 1,000 patient-days.
Total mean antibiotic use remained stable over time and amounted to 1,172 DDD/1,000 patient-days (range 531 to 2,471). Carbapenem use almost doubled to an AD of 151 in 2008. Significant increases were also calculated for quinolone (AD of 163 in 2008) and third-generation and fourth-generation cephalosporin use (AD of 117 in 2008). Aminoglycoside consumption decreased substantially (AD of 86 in 2001 and 24 in 2008). Resistance proportions were as follows in 2001 and 2008, respectively: methicillin-resistant Staphylococcus aureus (MRSA) 26% and 20% (P = 0.006; trend test showed a significant decrease), vancomycin-resistant enterococcus (VRE) faecium 2.3% and 8.2% (P = 0.008), third-generation cephalosporin (3GC)-resistant Escherichia. coli 1.2% and 19.7% (P < 0.001), 3GC-resistant Klebsiella pneumoniae 3.8% and 25.5% (P < 0.001), imipenem-resistant Acinetobacter baumannii 1.1% and 4.5% (P = 0.002), and imipenem-resistant K. pneumoniae 0.4% and 1.1%. The resistance densities did not change for MRSA but increased significantly for VRE faecium and 3GC-resistant E. coli and K. pneumoniae. In 2008, the resistance density for MRSA was 3.73, 0.48 for VRE, 1.39 for 3GC-resistant E. coli and 0.82 for K. pneumoniae.
Although total antibiotic use did not change over time in German ICUs, carbapenem use doubled. This is probably due to the rise in 3GC-resistant E. coli and K. pneumoniae. Increased carbapenem consumption was associated with carbapenem-resistant K. pneumoniae carbapenemase-producing bacteria and imipenem-resistant A. baumannii.
PMCID: PMC2911759  PMID: 20546564

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