SummaryLateral sphincterotomy diminishes internal anal sphincter hypertonia and thereby reduces anal canal pressure. This improves anal mucosal blood flow and promotes the healing of anal fissures. However, sphincterotomy can be associated with long term disturbances of sphincter function. The optimal treatment for an anal fissure is to induce a temporary reduction of anal canal resting pressure to allow healing of the fissure without permanently disrupting normal sphincter function. Broader understanding of the intrinsic mechanisms controlling smooth muscle contraction has allowed pharmacological manipulation of anal sphincter tone. We performed an initial Medline literature search to identify all articles concerning "internal anal sphincter" and "anal fissures". This review is based on these articles and on additional publications obtained by manual cross referencing. Internal anal smooth muscle relaxation can be inhibited by stimulation of nonadrenergic non-cholinergic enteric neurones, parasympathetic muscarinic receptors, or sympathetic adrenoceptors, and by inhibition of calcium entry into the cell. Sphincter contraction depends on an increase in cytoplasmic calcium and is enhanced by sympathetic adrenergic stimulation. Currently, the most commonly used pharmacological agent in the treatment of anal fissures is topical glyceryl trinitrate, a nitric oxide donor. Alternative agents that exhibit a similar eVect via membrane Ca 2+ channels, muscarinic receptors, and or adrenoceptors are also likely to have a therapeutic potential in treating anal fissures.
"Surgical" palliation of obstructing colorectal carcinomas may involve resection with or without stoma formation, formation of a stoma alone, a colonic bypass procedure, or no procedure at all. Palliative surgical procedures confer a significant morbidity and mortality. Factors associated with increased mortality for colorectal cancer include advancing age of patient, advancing stage of the disease and the necessity for an emergency procedure. Advanced obstructing malignant lesions pose a clinical dilemma as the risks and time of recovery from surgery have to be balanced against providing a dignified quality of remaining life. Self expanding metal stents (SEMS) for acutely obstructing advanced colorectal carcinomas provide a cost effective option that avoids surgery in a usually frail group of patients. They can be inserted under sedation, rapidly decompress the colon and lead to an early return of colonic function. The procedure is carried out endoscopically with radiological assistance to determine a lumen and to confirm adequate stent placement. SEMS are not suitable for low rectal lesions and are more difficult to place in those that traverse colonic flexures. Complications from successful SEMS placement include migration and stent occlusion. The morbidity associated with SEMS is associated with migration or perforation of the colon during placement, pain and less commonly haemorrhage. Despite these problems most patients can be successfully decompressed without further endoscopic or surgical reintervention and allow satisfactory palliation.
INTRODUCTION Anal fissures are commonly encountered in routine colorectal practice. Developments in the pharmacological understanding of the internal anal sphincter have resulted in more conservative approaches towards treatment. Simple measures are often effective for early fissures. Glyceryl trinitrate is well established as a first-line pharmacological therapy. The roles of diltiazem and botulinum, particularly as rescue therapy, are not well understood. Surgery has a defined role and should not be discounted completely.METHODS Data were obtained from Medline publications citing 'anal fissure'. Manual cross-referencing of salient articles was conducted. We have sought to highlight various controversies in the management of anal fissures.FINDINGS Acute fissures may heal spontaneously, although simple conservative measures are sufficient. Idiopathic chronic anal fissures need careful evaluation to decide what therapy is suitable. Pharmacological agents such as glyceryl trinitrate (GTN), diltiazem and botulinum toxin have been subjected to most scrutiny. Though practices in the UK vary, GTN or diltiazem would be suitable as first-line therapy with botulinum toxin used as rescue treatment. Sphincterotomy is indicated for unhealed fissures; fissurectomy has been revisited and advancement flaps have a role in patients in whom sphincter division is not suitable.
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