Doctors in Sri Lanka have removed a 3.1kg (6.8lb) bladder stone from a man – which they believe to be the largest of its kind on record.

The procedure was carried out last week at a hospital in Trincomalee, in the east of the country.

The 55-year-old patient had been admitted to hospital after suffering a stroke. But while receiving treatment, doctors found stones in his urinary bladder after noticing that he was experiencing difficulty urinating.

During surgery, doctors removed the bladder stone – it weighed as much as a full-term baby and was around the size of an ostrich egg.

“According to available records, it is the largest bladder stone ever documented and removed through surgery,” Dr Prahalahan Balakrishnan, who led the surgery, told BBC Sinhala.

He added that the patient was in “very good health”.

The patient remains at the hospital and is continuing to receive treatment for his other medical conditions, doctors said.

Dr Balakrishnan added the stone would have been in the patient’s bladder for about five to 10 years.

Bladder stones are formed when minerals in the urine crystallise, turning into solid lumps.

They commonly occur when the bladder does not empty completely, leaving concentrated urine that can turn into crystals.

Small bladder stones, sized like grains of sand, can pass on their own. But stones bigger than 1cm often block urine flow and require medical intervention. A bladder stone that is larger than 4cm is considered giant.

According to the Guinness World Records, the largest bladder stone was removed from a patient in Brazil in 2003. It weighed 1.9kg (4.2lb) and had a length of 17.9cm (7in).

The bladder stone removed in Sri Lanka last week measured around 17cm-long.