By:
Dr. Antonio Brillantino, SIUCP-ETS National Councilor
Dr. Pasquale Talento, President of SIUCP-ETS
Anal fissure represents a benign pathology characterized by a linear or oval ulceration of the anus (figures 1 and 2). It is generally localized at the level of the posterior commissure (up to 90% of cases) although it can affect, in the minority of patients, the anterior and lateral portion of the anal canal.
This is a very frequent condition, representing, in Italy, the second cause of proctological visits after haemorrhoids.
The pathogenesis is multifactorial although a major role appears to be played by the hypertonicity of the internal anal sphincter. According to one of the most accredited pathogenetic hypotheses, anal fissure typically appears after trauma to the anus caused by the passage of hard stools or irritation from diarrhea. Subsequently, the reflex hypertonicity of the internal anal sphincter, caused by the intense anal pain following the appearance of the fissure, would predispose the mucosa of the anus to ischemia and prevent the healing of the fissure itself, generating a vicious circle.
As it’s simple to imagine, unlike haemorrhoidal pathology, the typical clinical presentation of anal fissure includes intense pain referred to the anal-perineal region which occurs during defecation and persists for hours afterwards, possibly associated with slight bleeding. Occasionally, especially in women, the main complaint reported is bleeding, rather than pain. An asymptomatic fissure should raise suspicion of Crohn's disease.
The diagnosis of anal fissure can be strongly suggested by the patient's medical history and can be confirmed, in most cases, by direct visualization of the fissure through splaying of the buttocks and during effort with the patient in the left lateral or prone position. The differential diagnosis includes abscess, thrombosis of the external haemorrhoid, anal cancer, anal pruritus, and a variety of anogenital infections. In case of diagnostic doubt, evaluation of the anus under anesthesia and instrumental tests such as anoscopy, rectosigmoidoscopy and three-dimensional endoanal ultrasound can be used. As part of the diagnostic process, the performance of anorectal manometry may be indicated to confirm anal hypertonicity and, in the event of ineffectiveness of medical therapy, to support the surgeon in choosing the most suitable operative treatment.
From a therapeutic point of view, a conservative approach based on dietary and behavioural rules is indicated in patients with acute anal fissure in order to favour the evacuation of soft and formed stools, breaking the vicious circle that can be the basis of chronicity. Dietary hygiene rules can be supported by the use of painkillers and local ointments with muscle relaxing and healing properties.
In the chronic phase of the disease, conservative treatment based on ointments with a muscle-relaxing effect (for example, topical nifedipine 0.3% plus lidocaine 1.5% or nitrates) can represent the first-line therapy, possibly associated with ointments with film-forming properties, anti-inflammatory and healing agents such as, for example, the gel containing extracts of Propionibacterium acnes. In case of failure of conservative therapy, local treatment with botulinum toxin is used in some centers as second-line therapy.
In case of chronic anal fissure resistant to medical treatment, a surgical strategy is indicated. Surgical options are varied and include pneumatic anal dilation, internal lateral sphincterotomy, fissurotomy and fissurectomy with or without anocutaneous flap. The choice of the most appropriate surgical treatment depends on the clinical picture, age, sex, previous operations, risk of incontinence and surgical risk and can also be supported by the findings of three-dimensional endoanal ultrasound and those of anorectal manometry.
Figure 1: Acute anal fissure
Figure 2: Chronic anal fissure
Figure 3: Chronic anal fissure complicated by abscess: ultrasound finding (three-dimensional endoanal ultrasound)