Christian Wong

Recently introduced qacA/B genes in Staphylococcus epidermidis do not increase chlorhexidine MIC/MBC

OBJECTIVES Chlorhexidine is used as a disinfectant to prevent surgical infections. Recently, studies have indicated that chlorhexidine usage has selected methicillin-resistant Staphylococcus aureus strains that are tolerant to chlorhexidine and that this may be related to the presence of the qacA/B-encoded efflux pumps. Here, we evaluated if high-level exposure to chlorhexidine selects for tolerant colonizing Staphylococcus epidermidis and we addressed the consequences of long-term exposure to chlorhexidine. METHODS Chlorhexidine susceptibility and carriage of qacA/B was determined for colonizing S. epidermidis isolated from scrub nurses heavily exposed to chlorhexidine and were compared with isolates from non-users of chlorhexidine hand rubs. S. epidermidis blood isolates from the 1960s, before the wider introduction of chlorhexidine to the market, were also tested and compared with recently collected S. epidermidis blood isolates. RESULTS There was no correlation between the use of chlorhexidine in scrub nurses and the presence of qacA/B genes in S. epidermidis isolates or increased MICs/MBCs of chlorhexidine for S. epidermidis isolates. While 55% of current blood isolates harboured the qacA/B genes, none of the 33 historical S. epidermidis isolates did, although their MICs and MBCs of chlorhexidine were comparable to those for current isolates. CONCLUSIONS Chlorhexidine used as a hand rub does not select for S. epidermidis isolates with increased MICs or MBCs of chlorhexidine. However, the absence of qacA/B genes in S. epidermidis isolates obtained in the 1960s suggests that long-term use of biocides like chlorhexidine or related compounds may select for the presence of qacA/B genes.

The Effect of Botulinum Toxin A Injections in the Spine Muscles for Cerebral Palsy Scoliosis, Examined in a Prospective, Randomized Triple-blinded Study.

Study Design. A prospective, randomized triple-blinded cross-over design treating with either botulinum toxin A (BXT) or saline (NaCl). Objective. To examine the efficacy of BTX treatment in cerebral palsy scoliosis (CPS). Summary of Background Data. Intramuscular injections with BTX have been used off label in treating CPS. 1 prospective study has been conducted, demonstrating in both radiological and clinical improvement, whereas showing no side effects or complications. Methods. Subjects (brace-treated CPS between 2 and 18 yr) were injected using ultrasonic-guidance with either NaCl or BTX in selected spine muscles with 6 mo intervals (block randomization, sealed envelope). Radiographs of the spine and clinical follow-up were captured before and 6 weeks after each injection. Primary outcome parameter was radiological change in Cobb angle, where a 7° change was regarded as an effect (1 SD). Radiological parameters were measured before and 6 weeks after treatment by 3 experienced doctors separately. Moreover, clinical results were evaluated by the pediatric quality of life score and systematic open questioning of the parents about the childs wellbeing. Subjects, researchers, and monitors were blinded during the trial. Appropriate permissions (2008-004584-19) and no funding were obtained. Results. 16 cerebral palsy patients (GFMCS III-V) with CPS were consecutively included, whereas 6 patients were excluded. There were no drop-outs to follow-up, but 1 possible serious adverse event of pneumonia resulting in death was recorded and the study was terminated. No significant radiological or clinical changes were detected when compared with NaCl injections using Wilcoxon matched pair signed-rank test. Conclusion. No positive radiological or clinical effects were demonstrated by this treatment, except for the parents initial subjective but positive appraisal of the effect. However, the study was terminated due to 1 possible severe adverse event and scheduled numbers needed to treat (hence power) were not reached. Level of Evidence: 1

Does elite swimming accelerate lumbar intervertebral disc degeneration and increase low back pain? A cross-sectional comparison

PurposeThe aim was to elucidate elite swimming’s possible influence on lumbar disc degeneration (DD) and low back pain (LBP).MethodsLumbar spine MRI was performed on a group of elite swimmers and compared to a matched Finnish population-based no-sport group.ResultsOne hundred elite swimmers and 96 no-sport adults, mean age 18.7/20.8, respectively, participated. Overall, the two groups had similar prevalence of DD. Swimmers had more DD in the upper lumbar spine but tended to have less DD at the lowest level. Prevalence of bulges and disc herniations were similar, but swimmers had significantly more bulges at L4–5. The swimmers reported less LBP, although not significantly (N.S.). If degenerative findings were present, the association between them and LBP was stronger in the no-sport group.ConclusionElite swimmers and controls had similar prevalence of DD and LBP, although the pattern of DD differed between the groups. In case of DD, swimmers reported less LBP, although N.S.

Polyethylene Wear in Total Hip Arthroplasty for Suboptimal Acetabular Cup Positions and for Different Polyethylene Types: Experimental Evaluation of Wear Simulation by Finite Element Analysis Using Clinical Radiostereometric Measurements

We have examined the effects of optimal and sub-optimal cup position and different types of polyethylene on the simulated polyethylene wear. Finite Element (FE) Analysis was used, and ultra high molecular weight (UHMWPE), highly cross-linked (HCL), and E vitamin stabilized (E-poly) polyethylene were examined. We found structural stress parameters to be three times higher for a steep cup compared with a cup in optimal position. There were no differences in predicted polyethylene wear for the three examined polyethylene liners.

The effects of rotation on radiological parameters in the spine

Background Vertebral rotation in straight spines or in spines with small scoliosis may potentially affect measurement of radiological parameters in both the frontal and sagittal plane. This is important, since it could lead to potential misdiagnosis of scoliosis and other clinical consequences, and until now, this has not been examined. Purpose To examine the effect of axial vertebral rotation of the spine on measurement of common radiological parameters. Material and Methods Reconstructions from computed tomography scans of 40 consecutive included and anonymized patients with straight spines or small scoliosis. Fourteen sagittal and coronal reconstructions covering the whole pelvis and spine were executed. Radiographic parameters in both the frontal and sagittal plane were measured blinded and separately by three doctors. These parameters were evaluated for inter-rater reliability using intraclass correlation coefficient and mixed model analysis for the effects of rotation. The parameters were also analyzed sub-stratified according to “Lenkes classification” and 15 sub-categories of thoracic and lumbar Cobbs angle (CA). Results Vertebral rotation in general does not have any significant effects in both the frontal and sagittal plane. However, there are significant effects on CA and spinopelvic radiologic parameters in extreme rotation or for larger scoliosis. Inter-rater reliability was very good to good. Conclusion In conclusion, axial spinal rotation does not influence common radiological parameters in the frontal and sagittal plane, except in cases of extreme rotation or large scoliosis for selected parameters; thus, this does not lead to potential misinterpretation in scoliosis diagnosis, treatment, or research.

Complications and patient-injury after ankle fracture surgery. −A closed claim analysis with data from the Patient Compensation Association in Denmark

BACKGROUND The Patient Compensation Association (PCA) receives claims for financial compensation from patients who believe they have sustained damage from their treatment in the Danish health care system. In this study, we have analysed closed claims in which patients suffered injuries due to the surgical treatment of their ankle fracture. We identified causalities contributing to these injuries and malpractices, as well as the economic consequences of these damages. METHODS Fifty-one approved closed claims from the PCA database from the years 2004-2009 were analysed in a retrospective systematic review. All patients were adults with an iatrogenic injury, and received compensation. A root cause analysis was performed to identify whether the patient suffered the damage preoperatively, during surgery or postoperatively, and to determine the level of education of the injurious doctor. Economic compensation, co-morbidities and end-result complications were registered. RESULTS In 9 of the cases the injuries happened preoperatively, but the majority of the injuries, namely 34 occurred during surgery. In 21 of the cases the damage happened postoperatively. Thirty percentages of the patients were mistreated in more than one phase. Level of competence was medical specialists in 2/3 and junior doctors in 1/3 of the cases. In the preoperative phase both groups were equally responsible for the inflicted damage. In the perioperative- and postoperative group, medical specialists inflicted the majority of damages. General recommendations regarding ORIF were not followed in 21/49 of the perioperative damages. The pronation fracture was the most common. The patients received a total average compensation of 17.561 USD each. CONCLUSION Managing the complex ankle fracture, requires considerable experience. This study indicates that extra attention should be paid to the most technically demanding fractures as the pronation-external-rotation-, diabetic- and fragility fractures. Surgeons should follow the recommendations for ORIF. Emphasis should also focus on adequate postoperative plans. This study finds a high readmission-burden, re-operation rate and great expenses in form of compensation.