Question

36-year-old man with severe pain during and after defecation and occasional streaks of blood. Posterior midline anal fissure with exposed internal sphincter fibres and sentinel skin tag. Symptoms persist despite stool softeners and topical treatment; increased resting tone, normal continence, no previous sphincter injury. Most appropriate definitive surgical treatment?

• A. Uncontrolled manual anal dilatation (Lord's procedure)
• B. Advancement flap
• C. Excision of sentinel tag alone
• D. Lateral internal sphincterotomy

Hint:

Chronic fissure with sentinel tag and high resting tone is treated surgically by lateral internal sphincterotomy.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
This is a chronic anal fissure. The signs are a posterior midline tear, exposed internal sphincter fibres and a sentinel skin tag at the lower end.
The cause is a vicious circle. A hard stool tears the anoderm, pain triggers spasm of the internal anal sphincter, the raised tone cuts blood flow to the posterior midline, and the tear fails to heal.

Step 2: Key Approach:
Acute fissures are treated medically with stool softeners, fibre, sitz baths and topical agents such as nitroglycerin or diltiazem.
A fissure is called chronic when it lasts more than 6 weeks or shows a sentinel tag and visible internal sphincter fibres. If medical care fails, surgery is done.
The surgery of choice is lateral internal sphincterotomy. It cuts the lower part of the internal sphincter, so the tone falls, the pain goes and the fissure heals.

Step 3: Apply to this patient:
He has symptoms despite stool softeners and topical treatment. He has increased resting tone, normal continence and no earlier sphincter injury.
All of these favour lateral internal sphincterotomy. Normal continence means there is a low risk of incontinence.

Step 4: Check option (A):
Lord's procedure is forceful stretching of the anal canal. It is uncontrolled, and it can tear the sphincters and cause incontinence.
It is no longer recommended. So option (A) is wrong.

Step 5: Check option (B):
An advancement flap is used for fissures with low or normal tone, for anal stenosis, or for cases where sphincterotomy would be risky. It also helps if there is a risk of incontinence.
This man has high tone and good continence, so it is not the first choice. So option (B) is wrong.

Step 6: Check option (C):
Excising the sentinel tag alone does not remove the cause, which is the sphincter spasm. The fissure stays and the pain continues.
So option (C) is wrong.

Step 7: Check option (D):
Lateral internal sphincterotomy divides the internal sphincter only, up to the level of the dentate line, and never touches the external sphincter. It heals more than 90% of chronic fissures.
So option (D) is correct.

Final Answer:
The definitive surgery for a chronic anal fissure with raised tone after failed medical care is lateral internal sphincterotomy. This corresponds to option (D).