Preface

Benign anorectal disorders carry significant morbidity and financial burdens for the healthcare system. Benign anorectal disorders of structure and function are common in clinical practice. A patient consulting a doctor with anorectal complaints is likely to have progressed to the point of extreme discomfort.

Understanding anorectal anatomy is key to evaluating patients with the benign anorectal disease. The anorectal area is the terminal portion of the lower gastrointestinal tract. It is a part of the pelvic district that includes the urogenital organs and muscular, ligamentous, and connective tissue structures. As a functional unit, the anorectal area maintains fecal continence by acting as both a reservoir and an expulsion unit for feces.

The rectum has both intraperitoneal and extraperitoneal segments. The rectum begins at the confluence of the taeniae coli at the rectosigmoid junction. We commonly define the rectum as the last 12 cm above the anal verge. The anal canal is roughly 4 cm in length and extends from the anal verge to the proximal level of the levator ‒ the external anal sphincter complex. The sphincter mechanisms and the dentate line are of great importance when addressing the anal canal surgically.

The dentate line (pectinate line) is approximately 2 cm from the anal verge and is a place of transition from columnar epithelium (endoderm) to squamous epithelium (ectoderm). Between these layers is a transitional area called the cloacogenic zone. The dentate line divides the upper two-thirds from the lower third of the anal canal. Developmentally, this line represents the hindgut proctodeum junction, an important landmark because of differences in innervation, blood supply, and lymphatic drainage of the anal canal; several distinctions and pathologies are based upon the location of a structure relative to this line. The anal glands, of which there are typically four to eight, empty into the anal canal at the base of the anal columns. These extend through the full thickness of the mucosa and submucosa and even into the muscularis externa. They are branched, straight tubular glands with ducts lined with stratified columnar epithelium, and their function is mucus secretion.

For any problem, performing taking a complete history and performing a physical examination is mandatory. Bleeding, pain, discharge, swelling, changes in bowel habits, pruritus, prolapse, fever, incontinence, prior sexual contacts, and dyspareunia, are valuable information. Digital rectal and bimanual examinations are mandatory. Also important are sphincter tone, presence of gross blood, and presence or absence of hemorrhoids. Endoscopy (ano- and proctoscopy) is among the possible diagnostic tests. During the physical examination, temperature, body habitus, the abdomen, and the perineum require special attention.

This book summarizes the preferred approach to the evaluation and management of defecation disorders, proctalgia syndromes, hemorrhoids, anal fissures, and fecal incontinence in adults. Each section contains key concepts, recommendations, and summaries of the available evidence. Written by highly experienced physicians, the book provides detailed notes on the optimal management of these disorders including pre-and post-operative management. The chapters cover the entire range of benign disorders such as hemorrhoids, fissures, fistula-in-ano, anorectal injuries, anal incontinence, rectal prolapse, pelvic floor disorders, benign tumors and ulcers, and strictures.

> **Alberto Vannelli** Director, General Surgery, Valduce Hospital, Como, Italy

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Section 1

Anal Fistula

**Daniela Cornelia Lazar** Victor Babeș University of Medicine and Pharmacy, Timișoara, Romania
