A man needed to have a metal nut removed from his penis after it got stuck when he put it on his member for sexual pleasure.
The unidentified 34-year-old, from Hong Kong, went to his nearest A&E department two days after the hex nut became lodged.
Doctors tried to slide it off using jelly and giving the man painkillers – but it proved unsuccessful. They did not reveal how big the nut was.
Instead, the team had to resort to using a diamond disc cutter to cut open the metal and relieve him of his 'penile strangulation'.
The unidentified 34-year-old, from Hong Kong, went to his nearest A&E department two days after the hex nut became lodged (stock)
Medics at the United Christian Hospital's surgery department told the unusual tale in the journal Urology Case Reports.
Gruesome pictures showed the doctors using the disc cutter on his penis. They revealed he suffered two 'superficial' cuts during the procedure.
Writing in the journal, the team led by Chloe Hui Tung Yu said: 'Penile strangulation by constriction devices is a urological emergency.
'Patients tend to try their own methods for removal, and present late due to embarrassment.'
They added if safer methods fail 'electric metal cutting devices can be used with precautions taken' to avoid further injuries.
The team added that diamond disc cutters are usually used medically by orthopaedic surgeons for the cutting of implants.
Richard Viney, a urological surgeon in Birmingham, told MailOnline latex or elastic rings are easy to remove - but materials such as metal 'can create real problems'.
He said: 'As blood flows in the penis swells. If it swells to a diameter greater than the ring then the ring can’t be slid off.
'You rapidly develop a vicious cycle of swelling causing greater constriction. Over time, the tissues themselves start to die.
'This process makes this a medical emergency. The greater the swelling of the tissues the harder the removal becomes and the greater the damage done.'
Surgeons often make lots of small pinpricks to allow the tissue fluid to drain out. Once the swelling has been minimised the ring can be addressed.
Mr Viney added: 'If you're lucky it might slip off but this is rare. Usually it