Here is what my understanding about when to go for surgery but my today's appointment with my CRS(first Appointment) has lots of disappointments about the this particular CRS, cause in my first meeting he booked me for a LIS surgery.
My Study / Understanding based on my Fathers input (who is also a surgeon).
Step 1: First line of treatment: Lots of fiber, water, Sitz bath and rest. ( 1 week) >> if this fails to to step 2
Step 2: Nitro, Diltiaziem cream, or any vasodilator(refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls) and Sitz bath , lots of fiber, water and good sleep. (3 to 5 weeks)
Ste 3: Botox Injection with Sitz bath, Fiber, Water and Nitro or Diltiazem
Step 4: LIS (Open or Closed) Preferebly Open as its more visible to the surgeon and he can see what is cutting.( Lateral internal sphincterotomy is an operation performed on the internal anal sphincter muscle for the treatment of chronic anal fissure. The internal anal sphincter is one of two muscles that comprise the anal sphincter which controls the passage of feces. The procedure helps by lowering the resting pressure of the internal anal sphincter, which improves blood supply to the fissure and allows faster healing).
Step 5: the V-Y advancement flap, is generally reserved for recurrent fissures or fissures that are not associated with hypertrophy and hypertonicity of the internal anal sphincter.
After dealing with Fissure for almost two months and being close friends with doctors my understand of treating fissure is eating good food, healthy food which good in protein and fiber, lots of water, stools softener and continue this for at least 8 months even if the pains disappears. Its is very important to continue the treatment even if one is symptom free, often when we feel better we tend not to eat fiber rich good and leads to re-tear and make sure one takes Stool softner( Miralax or Milk of Magnesia).
I had a very bad experience with Miralax, it made my stood rough and hard that lead to re-tear but once i figured i stopped and started MOM which helped me a lot.
My suggestions: Though LIS is a gold standard but being conservative with invasive is always wise and try all and everything you can before going in for LIS but if you are a 24/7 pain for couple of months and thats causing you to be in bed than by all means go fo LIS.
Good Luck and my prayers and best wishes for AF sufferers.