Causes of anal fissure in men

Anal fissures caused by difficulty in defecation have become a very common phenomenon among people today, and the cause of anal fissures in men is also largely related to irregular diet and constipation. Men have greater pressure in life and work than women, so the intensity of work is often greater. Many men develop anal fissures due to habitual constipation, which requires more attention and timely medication.

1. Anatomical factors

The superficial part of the external anal sphincter forms the anococcygeal ligament behind the anus, which is relatively hard and has poor elasticity. Most of the levator ani muscles are attached to the sides of the anal canal, so the front and back of the anal canal are not as strong as the sides and are easily damaged. The anorectal angle formed by the anal canal and the rectum causes the back of the anal canal to bear high fecal pressure, which are all factors that cause anal fissures.

2. External injuries

Patients with chronic constipation have dry and hard stools, and they may easily injure the anal canal skin due to excessive force when defecating. Repeated injuries may cause deep lacerations that extend through the entire layer of skin, forming chronic infectious ulcers.

It has been reported that constipation causes anal fissures in 14% to 24% of cases, but constipation may also be a consequence of anal fissures due to the patient's fear of defecation.

In addition, birth injuries can also cause anal fissures, accounting for about 3% to 9%. Frequent bowel movements during diarrhea can easily damage the sensitive and tight anal canal, and repeated injuries can form chronic infectious ulcers.

3. Infection

Chronic inflammation near the tooth line, such as anal sinusitis in the posterior median, spreads downward and causes subcutaneous abscesses, which rupture and become chronic ulcers. The reason why anal canal injuries are difficult to heal is still unknown. Some people believe that it is mainly caused by injuries combined with infection. During infection, inflammatory cells can release procollagenase to prevent the regeneration and extension of epithelial tissue.

4. Ischemia

Recently, some people have proposed that ischemia in the posterior midline of the anal canal is the reason why anal fissures often occur in this area, because the distal end of the anal canal is supplied by the inferior rectal artery, which passes through the ischiorectal pouch and branches out into small branches through the anal sphincter to the mucosa, but most posterior commissures lack branches of the inferior rectal artery (accounting for 85%). Studies on capillary morphology also suggest that the capillaries inside the internal sphincter in the posterior midline are sparse. Some people have used laser Doppler blood flowmetry to measure that the blood flow in the posterior commissure of the anal canal is less than that in other quadrants. All of the above show that ischemia is indeed the main factor in the development of chronic anal fissures.

5. Anal canal stenosis

Stenosis of the anal canal caused by congenital malformation, trauma, or surgery makes it more susceptible to damage and anal fissures when dry feces pass through.

6. Internal sphincter tension

Patients with anal fissures have abnormal over-contraction of the internal sphincter. Due to injury or inflammatory stimulation of the anal canal, the anal sphincter is in a spasm state, which increases the tension of the anal canal and is prone to injury and anal fissures. Reflex internal sphincter spasm is currently considered to be an important reason why anal fissures are difficult to heal.

The anal pressure of patients with anal fissure is significantly higher than that of normal people, reaching 127.5±42.2kPa (956±316mmHg), while that of normal people is only 86.3±33.3kPa (647±250mmHg). This high pressure can be restored to near normal after anal dilation treatment.

7. Constipation

Some men prefer to be "quiet" and not "active", and are picky about food, which makes them prone to constipation. The dry and hard feces after constipation can easily scratch the skin of the anal canal and cause local infection, which can easily lead to anal fissures.

8. Narrow anus

The anal canal skin develops slowly, resulting in a narrow anal canal that is easily damaged and forms anal fissures.

9. Anal injury

Hard and dry stool, constipation or foreign matter can easily cause damage to the anal skin, which is the main factor causing anal fissure.

10. Anal infection

Anal fissures can also be caused by trauma, inflammation of the anus, chronic inflammation near the tooth line, etc. Inflammatory cells can release procollagen to prevent the regeneration and extension of epithelial tissue during infection.

In short, anal fissures are related to many factors. Mechanical trauma during defecation caused by long-term constipation and hard stool is the direct cause of most anal fissures. Existing lesions in the anal canal, such as anal sinusitis, anal papillitis, proctitis, tuberculosis, etc., can cause anal canal ulcers and anal fissures. Recent studies have shown that the increase in anal sphincter pressure during rest is closely related to the occurrence of anal fissures.