Jan. 31, 2003 DURHAM, N.C. -- Researchers from Duke University Medical Center and the Medical College of Wisconsin have shown that removing a portion, instead of all, of the spleen, can successfully treat children with a variety of congenital anemias while preserving important splenic immune function.
In the largest study of its kind in the U.S., the researchers performed the surgery, known as a partial splenectomy, on 25 children with congenital forms of anemia caused by abnormal red blood cells. Typically, these children suffer from fatigue, jaundice and extreme vulnerability to infections that can require repeated hospital or physician visits. Many also need repeated blood transfusions.
The results of the team's research were published today (Jan. 31, 2003) in the Annals of Surgery.
The spleen has two main functions: it produces immune system cells that protect the body from infection, and it also serves to clear unwanted materials -- including defective blood cells -- from the bloodstream. The majority of the children in the current study had hereditary spherocytosis, a condition marked by misshapen and rigid red blood cells. Because of their shape and rigidity, the red blood cells become trapped and destroyed in the spleen, resulting in an enlarged spleen and a reduction in the number of oxygen-carrying red blood cells.
"Many children with these disorders do fine with little or no intervention, but for those who have repeated infections and medical crises, their quality of life can be very poor," said Duke pediatric surgeon Henry Rice, M.D., principal investigator for the study. "Some of these patients receive total splenectomies, which can relieve many of the symptoms, but can leave patients at risk of fatal infections."
"There has been a resurgence in doing partial splenectomies in Europe for the past 10 years, but it still remains a very controversial procedure in the U.S.," Rice continued. "The goal is to take away enough of the spleen to help relieve the anemia and its symptoms, while leaving enough to maintain a viable immune function. Until now, there have been no large and conclusive studies showing the procedure can be performed safely with good outcomes."
Partial splenectomies have been slow to catch on in the U.S. for a number of reasons, according to Rice. First, the operation itself is technically difficult to perform. Secondly, somewhat like the liver, the spleen can regenerate itself, so physicians have worried that even if they perform a successful procedure, the spleen will eventually return to its original size and function.
"In our group of patients, some of which have been followed as long as six years, we have seen some regrowth of spleen tissue, but it has not been associated with the return of symptoms," Rice said. "The regrowth appears to vary widely from patient to patient, and it is not certain whether the new tissue acts exactly like the original tissue."
To date, none of the 25 children who have received the operation have needed another procedure, and none have succumbed to serious infections, Rice said.
While the procedure shows promise in improving the quality of life for these patients, Rice points out that it does not address the cause of these disorders, which have a genetic basis.
"However, these tend to be very sick children with a poor quality of life," Rice said. "We hope that this study will provide the necessary scientific basis to convince other surgeons that despite the difficulty of the procedure, it can benefit this group of children."
The surgeons removed between 80 to 90 percent of the spleen in the children followed in the study. According to Rice, a total splenectomy takes about one hour to perform, while a partial splenectomy takes about two hours. In both procedures, patients receive appropriate immunizations and antibiotics prior to surgery to reduce the risks of infections.
Of the 25 children who received partial splenectomies, 16 had hereditary spherocytosis, while nine had other red blood cell disorders, including pyruvate kinase deficiency and thalassemia. The children ranged in age from 1 to 14 years of age. As humans age, Rice said, the spleen becomes less important to maintaining overall good health.
While the results of current experience of the Duke and Wisconsin surgical teams appear promising, Rice believes that a prospective, long-term trial is needed to further refine the role of partial splenectomies in hereditary anemias, as well as possibly expanding the number of patients who could benefit to include those with similar rare disorders, including some forms of sickle cell disease.
The study was supported by the surgery departments at Duke and the Medical College of Wisconsin.
Other members of the research team included, from Duke, Russell Ware, M.D., and Michael Skinner, M.D. Other members were Keith Oldham, M.D., and Cheryl Hillery, M.D., Children's Hospital of Wisconsin, and Sara O'Hara, M.D., Children's Medical Center of Cincinnati.
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