DUBAI: One of the conjoined Yemeni twins who underwent a separation surgery has died after a severe drop in blood circulation and heart failure, state news agency Saudi Press Agency (SPA) reported on Tuesday.  The other twin is currently stable but is under observation in the Intensive Care Department of King Abdullah Specialist Paediatric Hospital in Riyadh, according to the Saudi team of specialized surgeons who performed the operation. “The surgical team had faced great difficulties and challenges during the separation process, which made the deceased’s condition critical after the operation,” SPA reported. Yousef and Yassin had undergone a “complicated” 15-hour long surgery to separate several of their organs under the directives of King Salman, the state media added.  A team of 24 doctors, led by Dr. Mutasem Al-Zughaibi, took part in the operation as part of an initiative by the King Salman Humanitarian Aid and Relief Centre (KSRelief).  “This was a complex operation due to the twin sharing in the sinuses, cerebral venous and parts of the brain,” Dr Nazar Al-Zughaibi, head of pediatric anesthesia at the King Abdullah Specialized Children’s Hospital at the National Guard Health Affairs in Riyadh, had told Arab News earlier. The team specializes in pediatric neurosurgery, plastic surgery, anesthesia, and nursing were involved in the procedure that had to be carried out in several stages: anesthesia, navigation planning, preparing for surgery, skincare, and preparation for brain tissues, bone and reconstruction.