How much common the Omental torsion, in a case of irreducible hernia became reducible spontaneously after induction of spinal aneasthesia?

30 year Male patient with Rt Indirect inguinal hernia for the past 3 years. He developed mild pain & partially reducible swelling for 3 days & no other obstructive symptoms. USG showed Hernia sac with omentum. On OT table after inducing spinal aneasthesia, hernia content reduced but sac was adherent to the cord structures & Hernioplasty completed.

He developed gradually increasing pain in Rt side of Abdomen from POD 2 onwards. CT showed Omental torsion with gangrene and normal bowel without perforation on POD 3, immediately laparotomy done & same findings noticed. How much common the Omental torsion?