A world apart

The patient, a 5-year-old named Hussein Mohamed from the United Arab Emirates, did what any boy his age might do prior to undergoing surgery at Boston's Children's Hospital. He played with Legos in the family waiting area, then tried to nap -- unsuccessfully -- with his mother crouched beside him in one corner of the room. When nurses wheeled Hussein into the operating room, he anxiously looked around for his father. Going under anesthesia, he clutched a small plastic dinosaur to his chest.

The 90-minute procedure, to correct a congenital urinary-tract malformation and reshape the boy's anus, was routine in many ways, too, as was the presence of pediatric surgeon Dr. Hardy Hendren, who at 78 maintains a schedule that would challenge surgeons half his age.

After the operation was completed, Hendren loosened his mask, turned to his OR team and said, "Nice job, everybody."

Just about everything else concerning Hussein and his care was far from ordinary, however, from the Arabic-speaking interpreter helping his parents conduct a newspaper interview to the fact that his twin brother, Hassan, had undergone virtually the same operation on the same floor three hours earlier.

The Mohamed brothers are once-conjoined twins who have been given the chance -- some might say the miracle -- of leading healthy, fully autonomous lives.

Hendren, who has operated on 15 sets of conjoined twins since the late 1960s, performed the initial 25-hour operation that separated Hassan and Hussein in April 1999. The 3-month-old twins faced each other and were fused from the chest wall to the genital area. As reported in a front-page Globe article two months after the surgery, "Their abdominal tissues were fused, their urinary tracts were tangled." Luckily, the twins had two healthy hearts, livers, and other vital organs.

Today, after many follow-up surgeries and notwithstanding persistent problems with incontinence, they are not only separate but equal to most 5-year-olds in energy, independence, and mischievousness.

"Have you seen the `Dennis the Menace' movie?" one hospital staffer remarked in affectionate tones. "Then you know what it's like having the twins around here."

For all their playfulness, the story of the Mohamed twins -- a story the family is now eager to share -- is a window into a biological and medical mystery that has long fascinated the public. "It's rare, and I suppose sort of mystical, too," Hendren acknowledges. "It seems to captivate the imagination of people."

Once every 50,000 births
Conjoined twins result from the incomplete division of a fertilized egg, or zygote, during the first two weeks following fertilization. Only about 700 such sets of twins, which occur once in every 50,000 births, have been born alive since medical records have been kept. Seventy percent are female. The majority are stillborn or survive only for a few days or weeks. The survival rate is pegged at 5 to 25 percent.

The most famous conjoined twins are Chang and Eng Bunker, born in 1811 in Siam (now Thailand). Together, Chang and Eng fathered 21 children and led successful lives as North Carolina businessmen before they died in 1874, at age 62. From 1824 to 1838 they toured with P.T. Barnum, who coined the term "Siamese twins."

In February, conjoined twin girls were born to a Maryland couple at the National Naval Medical Center in Bethesda. Erin and Jade Buckles were connected from the breastbone to the navel. They were successfully separated last month at Children's Hospital in Washington, D.C., at approximately the same age the Mohamed twins were when they were separated.

Other stories have sadder endings. Last July, a pair of 29-year-old conjoined Iranian sisters, Ladan and Laleh Bijani, underwent a grueling 50-hour operation in Singapore, hoping to achieve an independence they had desired for years. Although repeatedly warned of the risks involved, the women insisted on going forward with the operation. Joined at the head and sharing a major blood vessel, they died within 90 minutes of each other from uncontrolled bleeding.

Overall, improvements in technology, surgical techniques, and other factors have vastly increased the odds of surviving in cases like the Mohameds'.

"Even the last five to seven years has seen surgeries much more developed," says Will Degeraty of Prescott, Ariz., cofounder of Conjoined Twins International, a resource center for families of conjoined twins. The Degeratys are grandparents of successfully separated twin girls, Shawna and Janelle Roderick, now 8.

Degeraty started his group -- whose website gets more than 2,500 hits daily -- when family members could not find much helpful information outside medical journals.

"We've tried to help get it out in the open, that it's OK to talk about it and not some circus sideshow," Degeraty says.

His granddaughters are faring well, he says, although Shawna will have additional surgery this summer to correct a chest malformation. "They're very much aware of their special circumstances, and very close" Degeraty adds.

"The older the twins, the more difficult such choices become," says Hendren, who joined Children's staff in 1959 and served as chief of pediatric surgery from 1960 to 1982.

Hendren led the team that performed the first separation of conjoined twins in Boston in 1969. Maureen Ann and Marie Elizabeth Kobierski of Danvers survived the operation; Marie is now married and living on the North Shore. Her sister, who was developmentally challenged because of microcephaly, died last year of pneumonia. Among the most emotionally difficult cases he's handled was a set of twins who shared one heart and whose parents were informed that one twin would need to be "sacrificed" for the other to survive. For that reason, among others, Hendren advocates separation surgery as early as possible, "before too much emotional bonding takes place," as he puts it.

'An unusual heaviness'
The Mohamed family comes from Abu Dhabi. Abdulla Mohamed, the father, works as a constable for the ministry of the interior. The couple have three other children: two daughters, 11 and 10, and a 7-year-old son, who accompanied them on this trip to the United States. They arrived in April and are scheduled to depart at the end of this month. This is their third trip to America. One year after the initial surgery, they returned to the Boston area for 15 months while the boys underwent multiple surgeries to repair and reconstruct their fragile bodies.

Fatma Mohamed says through interpreter Amira Fahmy that the first warning signs occurred four months into the pregnancy, when she felt "an unusual heaviness" and was sent for an ultrasound. The picture revealed two fetuses that were conjoined.

"When I first went to the health clinic," Fatma recalls, "they transferred me to a bigger hospital, where I was told they could do the separation. I took it lightly at the time and did not think about it deeply."

It was only after their birth that she stared at her babies and the emotional shock hit her, she adds. "I started crying," she says. "I had a totally different reaction after I saw them."

Abdulla says he kept his own emotions in check until a doctor warned that one twin might not make it through surgery.

"I thought, `How can I lose one of my sons?' " he says. When it was suggested that any such operation would have to wait for a qualified urologist, they began seeking other opinions. A relative of Fatma's went on the Internet and found an article about Children's Hospital and Hendren. The family sought help from their country's prime minister and other government officials, who supported the plan to have Children's handle the case. Cost of the twins' medical care, travel, and housing, is being underwritten by the the United Arab Emirates and its embassy in the United States.

The boys were born on Dec. 16, 1998. They arrived in Boston the following March and underwent separation surgery a month later, spending a total of four months in the United States before returning home. On their second trip, they spent nearly 15 months living in Charlestown while commuting back and forth to the hospital.

While here, they enjoy walks in the Charlestown public gardens and around Boston Common. Fatma's sister has joined them here to help. Hassan and Hussein's older brother, Mohamed, 7, is also living with them in their small apartment in Charlestown. Other family members are looking after the couple's two daughters back home.

Hussein and Hassan lead what their parents describe as fairly normal lives. "They feel bad they're not in school yet -- they see their sisters and brother going and really want to go, too," says their mother, but problems with bowel incontinence have ruled out school so far. The parents hope they'll be in kindergarten next fall. Otherwise, the boys enjoy eating in restaurants and playing together.

"This morning," Fatma says on a recent visit to their apartment, "they were complaining about not being dressed alike. But we put them in different clothes to make it easier for the hospital" to tell them apart.

If one is crying and gets chocolate, she continues, he gives a piece to his brother. If the parents tell one boy something and ask him not to tell his brother, "he tells him immediately," she says, laughing.

Developmentally, Hassan and Hussein have suffered from being hospitalized so extensively yet seem to be catching up, both parents say. Mild hip dysplasia has also affected their gait, although they exhibit little difficulty walking, running, or romping around a neighborhood playground.

When they first returned home after being separated, the twins were famous for a short period, Abdulla says. "Then everything died down."

At what age will the twins be told more about the unusual beginning of their lives? "They know everything about themselves now," says Fahmy, the interpreter, and both parents laugh. "They show their incisions to everyone," she says. " `Look what happened to us!' they say."

During a recent visit with the family in Charlestown, the boys eagerly head for the local playground, thwacking each other on the head and arms and playfully shoving each other into the mulch.

"Say cheese!" their father implores as they pose for a photographer.

Back in the apartment, visitors are offered fruit, soda, and cookies by Fatma and her sister. The post-operative picture this time has been mixed, the parents report. Hassan in particular suffered from some surface bleeding, and the diarrhea problem that has plagued the boys has not entirely disappeared.

As Muslims, "We know God likes to test the faithful," Fatma says. "I never said, `Why me?' On the contrary, every time I pray, I thank God for this blessing."

Joseph P. Kahn can be reached at jkahn@globe.com.