Role of Microbiome in the Outcomes Following Surgical Repair of Perianal Fistula: Prospective Cohort Study Design and Preliminary Results

BACKGROUND

Anal fistulae are common, predominantly cryptoglandular, and almost invariably require surgical treatment. Recurrences are common for procedures other than fistulotomy regardless of technique and adequacy of repair. Growing evidence supports the pivotal role of specific intestinal bacteria in anastomotic failures after bowel resection. Anal crypts harbor colonic microbiota suggesting that similar mechanisms to anastomotic healing might prevail after anal fistula repair and hence influence healing. This study aims at assessing the potential role of the intestinal microbiome in the clinical outcomes after surgical repair of cryptoglandular anal fistula.

METHODS

This is a pilot prospective cohort study enrolling patients with anal fistula undergoing endoanal advancement flap. For microbiome analysis, stool samples are taken via rectal swab before the procedure; additionally, a portion of the fistula is collected intraoperatively after fistulectomy. Samples from groups with treatment failure are compared to samples from patients who healed after surgical repair. Alpha and beta diversities and differential abundance of microbial taxa are determined and compared between groups with DADA2 analytical pipeline.

RESULTS

Five patients have been enrolled to date (one female, four male). At median follow-up of 6 months (2-11), one patient experienced disease recurrence at 3 months. DNA from the 5 rectal swab and tissue samples was extracted, showing increased relative abundance of Enterococcus faecalis in samples from the patient who developed a recurrent fistula but not in those without recurrence.

CONCLUSION

These very preliminary data suggest that intestinal microbiome may represent a crucial determinant of the surgical outcomes after anal fistula surgery.

Anastomotic Techniques for Abdominal Crohn's Disease: Tricks and Tips

After surgical resection for Crohn's disease (CD) endoscopic recurrence is noted within few weeks and almost 80% of patients will have evidence of endoscopic recurrence at the anastomosis after ileocolic resection at 1 year. With time and if left untreated surgical recurrence will be detected at the preanastomotic segment or at the anastomosis in the vast majority of cases. It has become progressively apparent also based on these historical data that anastomotic configuration plays a major role in the subsequent recurrence of CD in surgically induced remission. In this article, we will review the evidence in the literature to support the different anastomotic configurations and we will discuss the principles of surgical prophylaxis of CD recurrence.

Risk factors for wound complications in patients undergoing primary closure of the perineal defect after total proctectomy

PURPOSE

Perineal wounds after complete proctectomy are at risk for failure, with dramatic consequences on patients' health and quality of life. This study is aimed at identifying risk factors for wound complications in patients undergoing primary closure of the perineal defect after total proctectomy.

METHODS

Data from 284 patients undergoing total proctectomy from 2002 to 2012 either at the University of Chicago Medical Center or the Catholic University of Rome Hospital were collected and analyzed.

RESULTS

Overall, the perineal wound complication rate was 21.8%. Successful conservative management was accomplished in 45.2% of cases. Complications occurred significantly more often in patients with a higher Charlson score index, with the diagnosis of rectal cancer, who had received preoperative radiation and who had a surgical drain placed at the time of initial surgery. Neoadjuvant radiation was the only significant risk factor at multivariate analysis (OR 4.40). In the rectal cancer subgroup, younger age, female gender, and preoperative radiation were predictors of wound complications. Based on that, a 3-point score (radiation, age, and gender (RAG)) was developed. Patients with a score of 3 had a 50% risk of developing a perineal wound complication.

CONCLUSIONS

Perineal wound complications are a common and burdensome problem after total proctectomy. Preoperative radiation is the single most significant and controllable risk factor predicting perineal wound failure. In the presence of multiple, non-modifiable risk factors, alternative approaches to primary closure should be considered in managing complex perineal defects.

Small bowel intussusception secondary to metastatic melanoma 15 years after complete excision of the primary tumor

INTRODUCTION

Primary intestinal melanoma is a rare entity, however the gastrointestinal tract, and particularly the small bowel, is a common site of recurrence from cutaneous melanoma. PRESENTATION OF CASE We report the case of a 48 year old woman with small bowel intussusception secondary to metastatic cutaneous melanoma, 15 years after excision of the primary tumor. The patient underwent an emergency small bowel resection with negative margins on final pathology.

DISCUSSION

Surgical resection is a palliative, yet necessary, procedure in the setting of small bowel obstruction due to intussusception secondary to intestinal metastatic melanoma. In case of bowel metastasis, presenting symptoms are nonspecific and do not provide significant clues to the differential diagnosis of the underlying disease. In some patients, complete surgical resection of early diagnosed bowel metastases is associated with prolonged survival. Systemic chemotherapy in these patients does not provide survival benefit.

CONCLUSION

The occurrence of bowel relapse after very long disease free interval, while highly unlikely in most tumors, should always be considered in the differential diagnosis of patients with previous history of cutaneous malignant melanoma presenting with gastrointestinal symptoms.