By Staff Writer

When Erin and Abby Delaney were born in July 2016, their parents faced one of the most extraordinary medical challenges imaginable. The identical twin girls were born craniopagus twins, meaning they were joined at the skull. Their journey would eventually lead to one of the most complex and carefully planned separation procedures ever performed at Children’s Hospital of Philadelphia (CHOP).

The twins were not born in Pennsylvania, as some social media posts have suggested. Their family lived in North Carolina, while the girls were delivered at CHOP in Philadelphia after doctors identified the condition during pregnancy. An ultrasound at about 11 weeks of gestation showed that the babies were joined at the tops of their heads. Further imaging revealed that the connection involved complex blood vessels and structures around their brains.

Born Premature and Facing a Difficult Beginning

Erin and Abby were delivered by cesarean section on July 24, 2016, at approximately 30 weeks of pregnancy. Each weighed just 2 pounds and 1 ounce. Because they were premature and remained physically connected, their early months were spent under intensive medical care at CHOP.

Doctors began preparing for separation almost immediately. The medical team included neurosurgeons, plastic and reconstructive surgeons, anesthesiologists, radiologists, intensive-care specialists, nurses and therapists. The challenge was not simply to separate the girls physically, but to ensure that each child would have adequate blood flow and protection for her brain afterward.

The twins shared part of a major venous structure known as the superior sagittal sinus, which drains blood from the brain. Separating this structure safely was considered one of the greatest risks of the operation.

Months of Preparation Before the Final Surgery

Rather than immediately attempting the final separation, the surgeons developed a staged strategy designed to make the eventual operation safer.

The team used computer-aided modeling and a three-dimensional printed model to study the girls’ unusual anatomy. At around three months of age, surgeons performed an initial procedure to separate portions of the fused skulls. A custom-designed distraction device then gradually moved the twins apart, creating additional space for the eventual surgery.

The process was carefully controlled over several weeks. Later, tissue expanders were placed beneath the skin around their heads. These devices gradually stretched the skin, providing additional tissue that could be used to cover the areas left after separation.

The innovative approach was particularly important because the doctors wanted to separate the girls while they were still very young. Their surgical team believed that younger brains might have a greater capacity to recover from the trauma of such a procedure.

An 11-Hour Operation

On June 6, 2017, when Erin and Abby were 10 months old, approximately 30 medical professionals came together for the final separation.

The operation lasted about 11 hours.

Surgeons carefully separated shared blood vessels, the protective membrane surrounding the brain, and other connected tissues. The most challenging stage involved the shared superior sagittal sinus. Advanced computer-assisted navigation helped surgeons understand the anatomy while working through structures that were difficult to see directly.

The girls were eventually separated and transferred to intensive care. Their recovery was closely monitored, and both required additional procedures and extensive rehabilitation.

The medical achievement was significant not only because the surgery succeeded, but also because of the techniques developed specifically for their case. The surgeons later published their experience in the New England Journal of Medicine, documenting the use of three-dimensional modeling, custom distraction devices and computer-assisted surgical navigation.

A Long Road to Recovery

Separation was only the beginning of another difficult stage.

After surgery, Erin and Abby spent months receiving intensive medical care, physical therapy, occupational therapy and developmental support. One of the girls was discharged from the hospital about four months after the operation, while the other remained hospitalized for approximately another month.

In total, the sisters spent 485 days at Children’s Hospital of Philadelphia before returning to North Carolina in November 2017.

Their recovery continued at home, with regular medical appointments and therapy. Doctors also anticipated additional reconstructive procedures as the girls grew, including treatment for areas of the skull that remained incomplete following the separation.

Exceeding Expectations

By 2019, Erin and Abby were described by their doctors and parents as making remarkable progress. At around two and a half years old, Erin was crawling and beginning to pull herself up, while Abby was sitting independently and moving around on her own. The girls were also beginning to interact with each other as individuals — a milestone their parents had once only hoped to see.

Their story attracted international attention because it represented an extraordinary combination of medical innovation, painstaking preparation and a family’s determination.

For their parents, however, the story was ultimately about much more than a groundbreaking operation. It was about watching two children grow into their own lives after beginning life physically connected to one another.

Erin and Abby’s journey demonstrates how advances in pediatric surgery can create possibilities that once seemed almost unimaginable. Their successful separation also highlights the importance of multidisciplinary medicine, advanced imaging and careful long-term rehabilitation.

Most importantly, their story remains one of courage, family love and hope — a reminder that even the most daunting medical challenges can sometimes be met with extraordinary teamwork and perseverance.

Sources

• Children’s Hospital of Philadelphia (CHOP) — Once Conjoined, Now Thriving: Abby and Erin Delaney
• Children’s Hospital of Philadelphia (CHOP) — High-Tech Tools, Tight Teamwork Were Key to Separating Infant Girls Joined at the Head
• New England Journal of Medicine — Separation of Craniopagus Twins by a Multidisciplinary Team, January 2019
• Children’s Hospital of Philadelphia — Home for the Holidays: Formerly Conjoined Twins, Erin and Abby Delaney Depart CHOP
• The Philadelphia Inquirer — Twins born joined at the head exceeding expectations 19 months after separation at CHOP

This article is based on publicly available medical and news reports. It does not claim to provide a current medical update beyond the latest reliable information located in the cited sources.