The straining could be causing the anal fissure or at least making it worse. I would recommend you stop straining when trying to have a bowel movement. If it can't come out without straining, I would recommend talking with your doctor about this.
I overcome constipation by taking lot of water, so that I keep my bowel clean every day. However, I do strain a bit during bowel movement.
Are you constipated at all? Do you strain when trying to have a bowel movement?
When I visited a gastroenterologist, he pressed hard with his finger on my rear saying there he can feel some small cuts and a gutter little inside the anus. While he inserted his finger and pressed hard, the paid was radiating in my leg, and went all the way down to my toes.
He was saying that I can't live with anal fissure for 2 years which has become chronic now, asking me to go for a surgery. Should I go for surgery, if so will I get any relief from the groin and leg pain?
Actually the pain started in my groin and leg, just after 3 months of getting the anal fissure. The pain remains more constant and persistent with a dull pain throughout day and night.
Earlier for the groin and left pain, I did consult orthopedics, urologists, spine specialist, neurologistl, and none of them were unable to diagnose the root cause of my problem after several repeated tests (which showed normal), finally saying they can't treat my pain.
Depending upon where the fissure is located and the amount of inflammatory factors/chemicals that are being released from the area around the fissues it's possible the fissue could be affecting your leg and groin considering the amount of nerves that are in close proximity.
Welcome to the gastroenterology community! I would say that this would be unusual, but not impossible.