Second set of rare conjoined twins separated at Great Ormond Street Hospital in less than 12 months

An expert team at Great Ormond Street Hospital (GOSH) has successfully separated a very rare set of twin boys joined at the top of the head, less than a year after separating two similarly conjoined sisters. 

Brothers Yiḡit and Derman Evrensel began their treatment at GOSH 10 months after sisters Safa and Marwa Ullah were successfully separated by the same team of specialists at the hospital in 2019. 

It is incredibly rare for twins born joined at the top of the head – known as craniopagus twins - to be boys. Only 5% of conjoined twins are craniopagus, and less than a third of craniopagus twins are boys. 

Lessons learnt from the successful separation of Safa and Marwa in 2019 and further sets of craniopagus twins in 2006 and 2011, meant the surgical and medical team at GOSH had an even better understanding of these complex procedures and the ongoing care Yiḡit and Derman would need. 

This clinical experience and advances in the use of cutting-edge equipment at the world-leading hospital meant Yiḡit and Derman’s separation could be achieved in around half the time needed to separate Safa and Marwa. Completing the separation over this shorter period of time has supported the boys’ recovery and is hoped will lead to better outcomes for them both. 

The two-year-old brothers from Turkey needed four major operations, totalling approximately 40 hours, and a number of smaller procedures. Their first operation took place in December 2019 and the final operation, which saw them separated, was completed on 28 January this year. 

Yiḡit and Derman were bought to GOSH for treatment when they were just over 17 months old because the central London hospital is one of the only sites in the world with the facilities and expertise required to separate and care for craniopagus twins 

The brothers continued to receive treatment at GOSH during the COVID-19 pandemic. They undertook daily physiotherapy and occupational therapy sessions to support their rehabilitation following surgery, with staff following strict infection control and prevention measures to ensure everyone’s safety. 

The GOSH surgical and medical team undertook extensive research using cutting-edge technology such as Virtual Reality (VR) and 3D modelling to create an approach to separating Yiḡit and Derman that would support the best outcomes for the boys. 

An exact replica of the boys’ heads was created in VR, allowing surgeons to explore and better understand their complex anatomy. Clinical teams used this technology to visualise the twins’ brains, skulls and network of blood vessels from every possible angle, helping them form the best plan for separation and after-care. 

3D models of Yiḡit and Derman’s brains, blood vessels and brain membranes were also printed from MRI and CT scans, allowing GOSH experts to practice procedures and plan where cuts should be made. 

The state-of-the-art technology and medical practices used in Yiḡit and Derman’s treatment will support GOSH to pioneer the use of these techniques in new areas of medicine and advance care for children and young people. 

A 100-strong team of GOSH staff from more than 15 disciplines across the hospital contributed to Yiḡit and Derman’s treatment and care. They were led by two world-leading surgeons: neurosurgeon Mr Noor ul Owase Jeelani and craniofacial surgeon Professor David Dunaway. 

Staff including plastic surgeons, anaesthetists, theatre nurses, operational department assistants, scientists and engineers with expertise in 3D modelling, VR technology and simulations played an important part in the treatment process. 

The boys’ care and rehabilitation following surgery involved specialists including paediatricians, ward nurses and allied health professionals including physiotherapists, occupational therapists and dietitians 

Mr Jeelani, who was Head of Neurosurgery at GOSH from 2012 to 2018, and Professor Dunaway, Head of the Craniofacial Unit at GOSH, said: “We are delighted to have been able to help Yiḡit and Derman and their family. Their strength throughout this process has been inspirational and we are hugely proud of them all. 

“The 100-strong team at GOSH who have been responsible for the boys’ treatment and care have shown immense dedication, compassion and expertise throughout this challenging seven-month journey. Yiḡit and Derman came to GOSH just a few months after we had successfully separated another set of craniopagus twins, so the team was able to apply this experience to advance how we undertake these complex surgeries and provide the high-quality ongoing care the boys needed. 

“GOSH really is one of the few places in the world that has the wide range of expertise and specialist infrastructure available to make a successful separation like this possible.” 

A team of theatre nurses played a vital role in planning the series of operations and ensuring the surgeries were a success. 

Maria Quiazon, Theatre Team Leader, Plastics and Craniofacial Team, said: "It was a really rewarding experience to work as part of the multidisciplinary team at GOSH that came together for Yiḡit and Derman’s surgeries. 

"The boys’ successful separation was only possible because of the close collaboration between the large group of specialists who carefully planned and completed these highly complex surgeries and the ongoing care. 

"This is the beginning of the next stage of Yiḡit and Derman’s journey through life and I wish them and their parents the best of luck for the future." 

The boys were discharged from GOSH in June. 

Over the last seven years, Mr Jeelani and Professor Dunaway have received over £1.3m from Great Ormond Street Hospital Children’s Charity for their Face Value programme – a vital area of research into new clinical techniques and equipment to improve the precision of craniofacial surgery. The Charity has supported further pioneering research by investing nearly £300,000 to help fund innovative techniques including 3D planning and printing, which has been key in helping the team separate the twins. Money raised by GOSH Charity, including through the Theatres for Theatres appeal, has also helped fund Theatre 10 at the hospital – a specialist theatre designed specifically for surgery on conjoined twins 

Yiḡit and Derman’s treatment and care at GOSH was funded through charitable contributions through Gemini Untwined. 

Facts and stats about craniopagus twins 

• Conjoined twins are very rare - only one in every 2.5 million births. 
• Only 5% of conjoined twins are craniopagus. Only 30% craniopagus twins are boys. 
• About 40% of twins fused at the head are stillborn or die during labour 
• A further third die within 24 hours. 
• The chance of craniopagus twins undergoing surgery is around one in 10 million births.