Fistulotomy and drainage of deep postanal space abscess in the treatment of posterior horseshoe fistula

BACKGROUND: Posterior horseshoe fistula with deep postanal space abscess is a complex disease. Most patients have a history of anorectal abscess drainage or surgery for fistula-in-ano. METHODS: Twenty-five patients who underwent surgery for posterior horseshoe fistula with deep postanal space abscess were analyzed retrospectively with respect to age, gender, previous surgery for fistula-in-ano, number of external openings, diagnostic studies, concordance between preoperative studies and operative findings for the extent of disease, operating time, healing time, complications, and recurrence. RESULTS: There were 22 (88%) men and 3 (12%) women with a median age of 37 (range, 25–58) years. The median duration of disease was 13 (range, 3–96) months. There was one external opening in 12 (48%) patients, 2 in 8 (32%), 3 in 4 (16%), and 4 in 1 (4%). Preoperative diagnosis of horseshoe fistula was made by contrast fistulography in 4 (16%) patients, by ultrasound in 3 (12%), by magnetic resonance imaging in 6 (24%), and by physical examination only in the remainder (48%). The mean ± SD operating time was 47 ± 10 min. The mean ± SD healing time was 12 ± 3 weeks. Three of the 25 patients (12%) had diabetes mellitus type II. Nineteen (76%) patients had undergone previous surgery for fistula-in-ano, while five (20%) had only perianal abscess drainage. Neither morbidity nor mortality developed. All patients were followed up for a median of 35 (range, 6–78) months and no recurrence was observed. CONCLUSIONS: Fistulotomy of the tracts along the arms of horseshoe fistula and drainage of the deep postanal space abscess with posterior midline incision that severs both the lower edge of the internal sphincter and the subcutaneous external sphincter and divides the superficial external sphincter into halves gives excellent results with no recurrence. When it is necessary, severing the halves of the superficial external sphincter unilaterally or even bilaterally in the same session does not result in anal incontinence. Close follow-up of patients until the wounds completely healed is essential in the prevention of premature wound closure and recurrence

Cancer after cholecystectomy: record-linkage cohort study

We investigated whether cholecystectomy is associated with subsequent cancer and, if so, whether the association is likely to be causal, by undertaking a retrospective cohort study using linked medical statistics, comprising a cholecystectomy group (n=39 254) and a reference cohort admitted for a range of other medical and surgical conditions (n=334 813). We found a short-term significant elevation of rates of cancers of the colon, pancreas, liver, and stomach after cholecystectomy, but no long-term elevation. Excluding colon cancers within 2 years of admission to hospital, the rate ratio for colon cancer after cholecystecomy, compared with the reference cohort, was 1.01 (95% confidence interval 0.90–1.12) and after 10 years or more follow-up it was 0.94 (0.79–1.10). It is highly improbable that the short-term associations between cholecystectomy and gastrointestinal cancers are causal, and we conclude that cholecystectomy does not cause cancer

Anterior anal sphincter repair can be of long term benefit: a 12-year case cohort from a single surgeon

BACKGROUND: Early surgical results of anterior sphincter repair for faecal incontinence can be good, but in the longer term are often disappointing. This study aimed to determine the short and long term outcomes from anterior sphincter repair and identify factors predictive of long term success. METHODS: Patients who underwent anterior sphincter repair between 1989 and 2001 in one institution were identified. Postal questionnaires were sent to patients, which included validated scoring systems for symptom severity and quality of life assessments for faecal incontinence. Patient demographics and risk factors were recorded as were the results of anorectal physiology studies and endoanal ultrasound. RESULTS: Eighty-five patients underwent repair by one consultant. The length of follow up ranged from 1 to 12 years. Most patients (96%) had early symptom improvement postoperatively. Of the 47 patients assessed long term (≥ 5 years), 28 (60%) maintained this success. Significant improvements in quality of life were observed (P < 0.001). Neither patient, surgical nor anorectal physiology study parameters were predictive of outcome. CONCLUSION: There were no predictive factors of outcome success and no changes in anal manometry identified, however anterior sphincter repair remains worthwhile. Changes in compliance of the anorectum may be responsible for symptom improvement

Surgery for fistula-in-ano in a specialist colorectal unit: a critical appraisal

ABSTRACT

Second Order Dimensionality Reduction Using Minimum and Maximum Mutual Information Models

Conventional methods used to characterize multidimensional neural feature selectivity, such as spike-triggered covariance (STC) or maximally informative dimensions (MID), are limited to Gaussian stimuli or are only able to identify a small number of features due to the curse of dimensionality. To overcome these issues, we propose two new dimensionality reduction methods that use minimum and maximum information models. These methods are information theoretic extensions of STC that can be used with non-Gaussian stimulus distributions to find relevant linear subspaces of arbitrary dimensionality. We compare these new methods to the conventional methods in two ways: with biologically-inspired simulated neurons responding to natural images and with recordings from macaque retinal and thalamic cells responding to naturalistic time-varying stimuli. With non-Gaussian stimuli, the minimum and maximum information methods significantly outperform STC in all cases, whereas MID performs best in the regime of low dimensional feature spaces

Management of obstetric anal sphincter injury: a systematic review & national practice survey

BACKGROUND: We aim to establish the evidence base for the recognition and management of obstetric anal sphincter injury (OASI) and to compare this with current practice amongst UK obstetricians and coloproctologists. METHODS: A systematic review of the literature and a postal questionnaire survey of consultant obstetricians, trainee obstetricians and consultant coloproctologists was carried out. RESULTS: We found a wide variation in experience of repairing acute anal sphincter injury. The group with largest experience were consultant obstetricians (46.5% undertaking ≥ 5 repairs/year), whilst only 10% of responding colorectal surgeons had similar levels of experience (p < 0.001). There was extensive misunderstanding in terms of the definition of obstetric anal sphincter injuries. Overall, trainees had a greater knowledge of the correct classification (p < 0.01). Observational studies suggest that a new 'overlap' repair using PDS sutures with antibiotic cover gives better functional results. However, our literature search found only one randomised controlled trial (RCT) on the technique of repair of OASI, which showed no difference in incidence of anal incontinence at three months. Despite this, there was a wide variation in practice, with 337(50%) consultants, 82 (55%) trainees and 80 (89%) coloproctologists already using the 'overlap' method for repair of a torn EAS (p < 0.001). Although over 50% of colorectal surgeons would undertake long-term follow-up of their patients, this was the practice of less than 10% of obstetricians (p < 0.001). Whilst over 70% of coloproctologists would recommend an elective caesarean section in a subsequent pregnancy, only 22% of obstetric consultants and 14% of trainees (p < 0.001). CONCLUSION: An agreed classification of OASI, development of national guidelines, formalised training, multidisciplinary management and further definitive research is strongly recommended

ICAR: endoscopic skull‐base surgery

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The epigenetic landscape of renal cancer

This is an accepted manuscript of an article published by Nature in Nature Reviews: Nephrology on 28/11/2016, available online: https://doi.org/10.1038/nrneph.2016.168 The accepted version of the publication may differ from the final published version.The majority of kidney cancers are associated with mutations in the von Hippel-Lindau gene and a small proportion are associated with infrequent mutations in other well characterized tumour-suppressor genes. In the past 15 years, efforts to uncover other key genes involved in renal cancer have identified many genes that are dysregulated or silenced via epigenetic mechanisms, mainly through methylation of promoter CpG islands or dysregulation of specific microRNAs. In addition, the advent of next-generation sequencing has led to the identification of several novel genes that are mutated in renal cancer, such as PBRM1, BAP1 and SETD2, which are all involved in histone modification and nucleosome and chromatin remodelling. In this Review, we discuss how altered DNA methylation, microRNA dysregulation and mutations in histone-modifying enzymes disrupt cellular pathways in renal cancers