What is testicular torsion that Tilak Varma suffered?

Cricketer Tilak Varma recently underwent emergency surgery after being diagnosed with testicular torsion, a medical emergency in which a testicle twists around the spermatic cord, cutting off its blood supply. The condition causes sudden and severe scrotal pain, swelling, nausea and vomiting. Without immediate treatment, the affected testicle can suffer permanent damage or even die.