Perspective Chapter: The Management of Chronic Anal Fissures

Abstract

Chronic anal fissure is a common complaint that is associated with excruciating anal pain and bright red bleeding associated to bowel movements. The classic findings during the physical examination are helpful in differentiating the different types of fissures (acute versus chronic and typical versus atypical). Most cases of chronic anal fissures are successfully treated with conservative measures such as dietary and lifestyle modifications, adequate bowel regimen, and topical muscle relaxants such as nifedipine, diltiazem, or nitroglycerine. Refractory cases are usually managed with botulinum toxins injections or more invasive approaches such as internal lateral sphincterotomy with excellent healing rates at the expense of risk of fecal incontinence. In patients without hypertonicity of the anal sphincter, cutaneous flaps can be used with remarkable results.

1. Introduction

An anal fissure is defined as a linear tear of the superficial lining of the anal canal (from the dentate line to the anal verge). As with many other anorectal conditions, it is often assumed to be hemorrhoids and can go undiagnosed, making it difficult to know its exact incidence. Most patients seeking help from a healthcare professional are those with persistent symptoms, given that many acute anal fissures resolve spontaneously.

Anal fissures classifications are simple and based on the length of symptoms (acute or chronic), and location in the anal canal circumference (typical or atypical). The treatment will depend on the type of fissure and associated patients’ conditions.

2. Pathophysiology

The exact pathogenesis of this condition has not been precise; however, different theories have been proposed.

The passage of hard bulky stools through the anal canal, anal intercourse or medical instrumentation are described in the mechanical theory as causing trauma on the mucosa overlying the anal canal, with documented hypertonicity of the anal sphincter [1, 2]. This finding is unclear if it is part of the cause or a consequence of the anal pain [3]. During straining, the anorectal angle (ARA) makes the posterior midline (PML) of the anal canal the most vulnerable location [4]. Nonetheless, loose and multiple liquid bowel movements are known to cause anal fissures as well.

Another theory is the one involving the relative ischemia in the PML of the anal canal, which may be aggravated by hypertonicity of the anal sphincter muscle. The combination of these factors creates a vicious cycle where open wound causes worsening pain, which causes anal muscles spasms and increased tone, consequently aggravating the local ischemia and ultimately precluding healing [5].

3. Clinical presentation

Severe sharp pain is a distinguishing characteristic of anal fissures. It is usually associated with bowel movements and can last minutes to hours. The intensity of the pain causes fear of bowel movements, and it is often described as if glass was passing through the anus. The anorectal pain caused by the fissure is commonly accompanied by bright red blood in the toilet.

Anal fissures are classified based on the duration of symptoms in acute (<6 weeks) and chronic (>6 weeks) and according to the location in typical (posterior/anterior midline) and atypical (lateral quadrants) (Figure 1).

Figure 1.

Anal fissure classification based on location. PML: posterior midline; and AML: anterior midline.

In chronic anal fissures, it is characteristic to find a triad of a sentinel skin tag (on the distal apex of the fissure), a hypertrophic anal papilla (on the proximal apex), and exposed hypertrophic internal sphincter muscle (Figure 2). Table 1 summarizes the characteristic symptoms, findings on examination, and associated pathologies depending on the type of fissure (Figure 3).

Figure 2.

Chronic anal fissure triad.

Type of fissure	Symptoms	Findings on examination
Acute	Presentation <6 weeks Bright red bleeding per rectum (BRBPR) Sharp pain, and/or burning associated with bowel movements (BM) Anal spasms after BM	Linear tear of the anoderm with clean edges Hypertonic anal sphincter on digital rectal examination (DRE)
Chronic	Symptoms present beyond 6–8 weeks Pain and bleeding associated with BM as in acute anal fissures	Sentinel skin tag at the external apex Hypertrophic anal papilla at the internal apex Exposed internal anal sphincter muscle Thickened raised edges
Type of fissure	Location and findings on examination	Associated pathologies
Typical	73–90% posterior midline (PML) 10–13% anterior midline (AML) 3% in both AML and PML Appearance as described above	Not associated with other diseases (excluding constipation)
Atypical	Anywhere in the anal canal, commonly off midline Deeper ulcerations	Malignancy Crohn’s disease Human immunodeficiency virus (HIV) Syphilis Tuberculosis

Table 1.

Characteristic symptoms, findings on examination, and associated pathologies on different types of anal fissures.

Lu and Herzig [6]; Jobanputra [7].

Figure 3.

Chronic AML fissure. White arrow: hypertrophic anal papilla. Yellow arrow: sentinel skin tag.

4. Diagnosis

The cardinal symptom of anal fissures is pain associated with defecation, and that can last several hours. Some patients describe it as “passing broken glass” to describe the sharp and burning nature of the pain. In many cases, pain is associated with bright red bleeding, which is why this condition is often misdiagnosed as symptomatic hemorrhoids (Figure 4).

Figure 4.

PML chronic anal fissure with thickened raised edges.

5. Treatment

5.1 Conservative (nonoperative) management

5.1.1 Dietary and lifestyle modifications

Conservative management such as diet and lifestyle modifications should be offered to all patients presenting with acute anal fissures, given the high healing rates (80–90%) and very few side effects associated with these measures [8]. On the contrary, chronic anal fissures only heal with conservative measures in a small group of patients (36%), as reported in a Cochrane review [9]. This is due to the increased anal sphincter tone, the reason why local agents aiming for sphincter muscle relaxation are offered early in the management.

The goal is to preserve an adequate consistency of the stools (formed), avoiding constipation, which helps with healing and preventing recurrences. This can be achieved by pursuing the following recommendations:

• Maintaining a high-fiber diet (20–30 gr per day) or psyllium supplements, with stool softeners as needed.

• Optimization of daily fluid intake to at least 8 glasses of 8 ounces.

• Warm water sitz baths to help relaxing the pelvic muscles.

• Avoid excessive straining and prolong sitting in the toilet (>3–5 minutes).

• Avoid vigorous perianal wiping.

5.1.2 Topical sphincter muscle relaxants

Muscle relaxants are widely used in the management of chronic anal fissures with sphincter hypertonicity. Either through the nitric oxide pathway or by blocking calcium channels in the cell wall, the aim is to relax the anal sphincter muscle to allow blood flow and, consequently, healing of the fissure [1, 2].

5.1.2.1 Glyceryl trinitrate (nitroglycerine)

This agent has been used for decades with healing rates of almost 70% (ranging from 49 to 68%). Recurrence rates have been reported from 51 to 67%. Although most patients report resolution of symptoms with proper use, headache is a well-known side effect experienced in almost 50% of users, leading to discontinuation of treatment in up to 20% of patients. Tachyphylaxis is another undesirable effect of this medication, discouraging further use in some patients.

The initial concentration described and used was 0.2%, prepared as a compound ointment, but several years later, 0.4% became available. Both concentrations can be applied twice a day, perianal or endoanal, for 6–8 weeks. However, the endoanal application of 0.4% ointment specifically has shown healing rates as high as 77%.

When comparing the type of application, perianal versus endoanal, the latter was associated with decreased frequency and severity of headaches. Several studies have investigated the ideal dose by comparing different concentrations from 0.1 to 0.4%, and most results have shown higher healing rates with 0.4% [10, 11].

5.1.2.2 Calcium channel blockers (nifedipine, diltiazem)

This group of topical agents work by blocking the influx of calcium into the cells, allowing relaxation of the anal sphincter muscle. They are considered the first-line treatment for chronic anal fissures due to their good efficacy and lower side effects compared with nitrates. These medications are not available in topical formulation; therefore, they must be prepared as compounds by specialty pharmacies, making availability more limited.

A meta-analysis of randomized controlled trials in the management of chronic anal fissures was published by Nevins and Kanakala, and their results reinforced the outcomes of other publications demonstrating that topical calcium channel blockers and glyceryl trinitrates have comparable healing rates; however, diltiazem 2% and nifedipine produce less often and less severe headaches and have better recurrence rates [12].

5.1.3 Chemical denervation (botulinum toxin)

Botulinum toxin is a protein produced by Clostridium botulinum, responsible for muscular relaxation by blocking the release of acetylcholine at the neuromuscular junction. The severity of the muscle relaxation and length of the effect is variable but can last several months (up to 4 months). Botulinum toxin type A is the most widely used, and despite not being specifically approved by the Food and Drug Administration (FDA) for the treatment of chronic anal fissures, it has been shown to significantly improve symptoms when injected directly in the internal anal sphincter muscle. It is relatively well tolerated, with less side effects than muscle relaxants, and despite the need for anesthesia to be applied, it is the second line of treatment for chronic anal fissures and an excellent alternative to surgery, particularly in patients considered high risk for fecal incontinence.

One of the challenges of this treatment is the lack of standardization of application techniques and dosages, including single or multiple injections directly in the internal and external sphincter muscles, in the intersphincteric space, and on the sides of the fissure. Since healing and recurrence rates seem to be similar with low and high doses, it is recommended to use the lowest dose needed to achieve healing to decrease the risk of fecal incontinence.

5.1.4 Topical anesthetic

Topical Lidocaine in gel or ointment is commonly used as an adjuvant in the management of the pain associated with anal fissures. Direct endoanal application is recommended, especially before and after bowel movements. Patients should be educated about its use, intended to help in reducing the pain rather than healing the fissure.

5.2 Operative management

Persistence of the anal fissure after uninterrupted medical treatment for at least 6 to 8 weeks, it is considered a failure of nonoperative management and often requires a surgical intervention.

5.2.1 Anal sphincter dilation

Mechanical stretching of a hypertonic anal sphincter muscle is one of the oldest methods described in the management of chronic anal fissures. Outcomes and details on the technique have shown significant variations in the literature. With the development of more effective treatment options, manual dilation is disfavored, reserving balloon dilation as an option in patients with an increased risk of incontinence.

5.2.2 Lateral internal sphincterotomy (LIS)

The surgical division of the anal sphincter was first described in early 1950s, and despite some variations in the technique, it remains the treatment of choice for hypertonic anal sphincter fissures. The initial description was at the site of the fissure in the posterior midline, which causes fecal soiling in up to 40% of patients due to the anatomic defect of the anal canal (“keyhole deformity”). After the introduction of the lateral sphincterotomy by Notaras in 1969, this procedure became the surgery of choice for patients who failed medical management [13].

5.2.3 Surgical details

As in most outpatient surgeries, our preference is to perform this procedure under spinal anesthesia; however, sedation and local anesthetic is another good option. Pre-operatively, patients receive fleet enemas the night before and the morning of the procedure. After positioning the patient in a prone Jack-knife position with both buttocks taped apart for better exposure of the perianal area and traditional sterile field preparation, a digital rectal examination and a circumferential anoscopy are performed. Antibiotics for surgical prophylaxis are not routinely offered in these cases.

The transection of the sphincter is performed on the right side to avoid bleeding from the left lateral hemorrhoid.

5.2.3.1 Open versus closed

The difference of these techniques is the creation of a radial surgical wound over the intersphincteric groove providing direct visualization of the internal sphincter muscle before transecting it (open approach), as supposed to the insertion of the scalpel in the intersphincteric space with subsequent turning medially and transection of the internal anal sphincter muscle (Figures 5 and 6).

Figure 5.

Open lateral internal sphincterotomy: (a) incision over intersphincteric groove, (b) separation of internal sphincter muscle with a hemostat clamp and division of the muscle using a scalpel, and (c) closure of the wound with absorbable suture (From: Lu and Herzig [6]).

Figure 6.

Closed lateral internal sphincterotomy: (a) identification of the intersphincteric groove, (b) insertion of a scalpel in the sphincteric groove, and (c) medial rotation of the scalpel and transection of the internal sphincter muscle (From: Lu and Herzig [6]).

The results of these two techniques have been studied in multiple opportunities, and in a Cochrane review updated in 2011, similar success and recurrence rates were reported. Fecal incontinence rates are also comparable [14].

5.2.3.2 Conservative versus traditional

The amount of divided muscle, defined by the length of the incision over the internal anal sphincter, differentiates these two approaches. Traditionally, the incision was made to the dentate line (associated with worse incontinence but less recurrence), but more conservative techniques transect the muscle to the level of the apex of the fissure [15].

Individualized care is imperative when deciding the length of the sphincterotomy, to properly balance the risk of incontinence with the healing of the fissure [16, 17]. Some factors to consider include but are not limited to age, gender, history of prior anorectal procedures, prior vaginal deliveries with or without episiotomies or tears, length of the anal canal, prior fissure treatments, consistency of the stools, medications, comorbidities, etc.

5.2.4 Fissurectomy

Fissurectomy has regained attention recently due to its simplicity and virtually no complications associated with the procedure. Whether or not the hypertrophic anal papilla and skin tag are excised, the curettage of the base of the fissure as well as the sharp excision of rolled and epithelialized edges, has been shown to promote healing. The goal is to create a fresh wound and remove fibrosis to facilitate healing by secondary intention. Recurrence rates are higher compared to LIS [18].

5.2.5 Advancement flaps

Patients without hypertonicity of the anal sphincter represent a special challenge, given that topical pharmacologic agents previously discussed aid with healing by relaxing the sphincter muscle. Cutaneous advancement flaps have been reported with excellent results in both types (hypertonic and hypotonic sphincter fissures), with high healing rates and no fecal incontinence [19]. Although this technique requires a certain degree of expertise, it offers a great alternative for patients without sphincter hypertonicity.

5.2.6 Surgical details

Performed as an outpatient procedure under spinal anesthesia is our preferred approach. Pre-operatively, patients receive fleet enemas the night before and the morning of the procedure. Patient are placed in prone Jack-knife position with both buttocks taped apart for a better exposure of the perianal area, and traditional sterile field preparation, a digital rectal examination and a circumferential anoscopy are performed. Antibiotics for surgical prophylaxis are not routinely offered in these cases. Fissurectomy is recommended to create a healthy bed of tissue that supports the cutaneous flap. A wide-base skin and subcutaneous tissue flap is created and advanced toward the anal canal providing full coverage of the fissure. Absorbable interrupted sutures are used to secure the flap in place. In our practice, we often create relaxing superficial incisions on the perianal skin to decrease the tension on the flap (Figure 7, Table 2).

Figure 7.

Dermal advancement flap creation: (a) sharp incision over the skin adjacent to the fissure, (b) dissection of skin and subcutaneous tissue to create a flap, and (c) after advancing the flap over the fissure, it is secure using absorbable sutures (From: Feingold and Lee-Kong [20]).

Type of treatment	Use	Healing rates (%)	Recurrence	Side effects
Nonoperative management	Acute fissures; Chronic fissures	80–90; 36
Calcium channel blockers	Chronic hypertonic fissures (first-line treatment)	71–92		Headaches
Nitrates	Chronic hypertonic fissures	49–68	51–67%	Headache 27–50%
Botulinum toxin	Chronic hypertonic fissures (second-line treatment)	45–73	28%	Fecal incontinence
Lateral internal sphincterotomy (LIS)	Chronic hypertonic fissures	93–96		Fecal incontinence 30–40%
Anocutaneous flap	Chronic hypotonic anal fissures	98

Table 2.

Summary of types of treatments, healing rates and recurrence rates.

6. Special situations

6.1 Crohn’s disease

Anal fissures are common in Chron’s patients. The atypical location in the lateral quadrants of the anal canal associated with other local (such as fistulas) and systemic symptoms facilitate the diagnosis. These fissures appear as deep ulcerations of the anal area, and adequate treatment involves the management of Crohn’s disease with systemic therapy, achieving resolution of symptoms in more than 50% of patients. Surgical intervention is recommended only in cases of complications such as abscesses; however, as a rule for this population of patients, excessive procedures should be avoided. Figure 8 shows a right anterior anal fissure with an associated posterior midline anal fistula in a Crohn’s patient.

Figure 8.

Right anterior anal fissure with an associated posterior midline anal fistula in a Crohn’s patient.

6.1.1 Immunosuppressed patients

This subset of patients, particularly those with Human Immunodeficiency Virus (HIV) infection, can develop typical and atypical anal fissures. However, the management can be quite different from non-HIV patients due to comorbidities associated with the disease and its treatment. These include but are not limited to decreased sphincter tone, loose consistency of the stools, impaired wound healing, and increased risk of developing serious infection complications. Therefore, individualized care is strongly advised before determining the best approach.

6.1.2 Anoreceptive patients

Unfortunately, anal fissures are not uncommon in patients with anoreceptive sexual behavior, and this is caused by direct trauma over the anal canal. The management is like those without a history of anal intercourse, ensuring adequate bowel habits and stool consistency. Topical muscle relaxants are also routinely used, and patients are educated to abstain from anal intercourse for the duration of treatment to enable complete healing of the fissures. In cases of failure to nonoperative management, surgical procedures may be necessary; however, caution should be exercised due to the increased risk of fecal incontinence in this population. A thorough discussion of the risks and benefits of any surgical intervention is recommended.

7. Conclusions

Chronic anal fissures are a common reason for colorectal surgery visits, and the diagnosis is usually made with a history of severe anal pain associated with evacuations and bright red bleeding, and physical examination findings of a tear in the anal canal. Nonoperative management with dietary modifications, bowel regimen, and topical muscle relaxants has high rates of achieving resolution of symptoms and healing of the fissures. In cases of failure despite proper medical treatment, a surgical intervention may be warranted. Internal lateral sphincterotomy is an excellent option with high success rates; however, a more conservative approach should be considered in those patients with an increased risk of incontinence. Low-tone fissures are effectively managed with dermal advancement flaps.