RESUMEN
Designing air quality policies that improve public health can benefit from information about air pollution health risks and impacts, which include respiratory and cardiovascular diseases and premature death. Several computer-based tools help automate air pollution health impact assessments and are being used for a variety of contexts. Expanding information gathered for a May 2014 World Health Organization expert meeting, we survey 12 multinational air pollution health impact assessment tools, categorize them according to key technical and operational characteristics, and identify limitations and challenges. Key characteristics include spatial resolution, pollutants and health effect outcomes evaluated, and method for characterizing population exposure, as well as tool format, accessibility, complexity, and degree of peer review and application in policy contexts. While many of the tools use common data sources for concentration-response associations, population, and baseline mortality rates, they vary in the exposure information source, format, and degree of technical complexity. We find that there is an important tradeoff between technical refinement and accessibility for a broad range of applications. Analysts should apply tools that provide the appropriate geographic scope, resolution, and maximum degree of technical rigor for the intended assessment, within resources constraints. A systematic intercomparison of the tools' inputs, assumptions, calculations, and results would be helpful to determine the appropriateness of each for different types of assessment. Future work would benefit from accounting for multiple uncertainty sources and integrating ambient air pollution health impact assessment tools with those addressing other related health risks (e.g., smoking, indoor pollution, climate change, vehicle accidents, physical activity).
RESUMEN
BACKGROUND: Several surgical procedures for the repair of fistulas between the rectum and the urethra or vagina have been reported. Our study was designed to assess the efficacy of the gracilis muscle flap in repairing recto-urethral and rectovaginal fistulas. METHODS: Gracilis muscle interposition flaps were performed in 35 patients (aged 38-78 years, mean: 58 years) using a perineal approach. Nine patients had rectovaginal fistulas due to Crohn's disease (n=3), previous surgery and pelvic irradiation for rectal (n=2) or cervical cancer (n=4). Twenty-six fistulas were recto-urethral. The aetiologies were Crohn's disease (n=4), brachytherapy after prostate cancer (n=14), iatrogenic injury to the rectum during radical retropubic prostatectomy (n=4), transurethral resection of the prostate (n=2) and recurrent peri-anal abscesses with fistulas (n=2). Twenty-five patients had undergone previous repair attempts; of these four underwent multiple procedures. Patient outcomes were assessed after surgical repair. The success rate was measured as the percentage of patients with a healed fistula after stomal closure. RESULTS: The mean follow-up was 28+/-15 months from muscle transposition and 22+/-14 months from stomal closure. Fistula closure with no recurrence could be achieved in 33 patients (94%). Two of the seven patients (29%) with Crohn's disease had a persistent fistula. There were neither intra-operative complications nor problems related to muscle desinsertion surgery. CONCLUSIONS: Recto-urethral and rectovaginal fistula closure using the perineal approach with pedicled gracilis muscle interposition is associated with minimal morbidity and a high success rate. It is an excellent option for patients with complicated fistulas for whom other surgical treatments have failed. Underlying Crohn's disease is associated with a higher complication rate.