Mind Over Matter
Originally published on October 28, 2011 in The Artful Brain under Nature Publishing Group (see original version)
The interesting clinical condition of craniopagus affords a thought-provoking debate over medical ethics. Here, we take a step back and decide whether it is ethical to for the physician to decide if the birth of such debilitated individuals should be allowed.
Ken Walker is a Canadian physician who claims that most doctors lack the "intestinal fortitude" to say that the birth of craniopagus twins "should never have happened." He goes on to say that that allowing such a birth is a "cruel experiment and will cost taxpayers millions of dollars in medical and social costs." He attempts to substantiate his utilitarian arguments by asserting that the Canadian "health care system cannot afford reckless expenditures of this kind." Finally, he claims that "Like it or not, we have reached a point where some medical decisions have to be based on financial realities" (Walker, 2007).
There are several assumptions underlying this argument. The first is that providing for these cases is a "reckless expenditure." Recent cases of craniopagus twins, such as Tatiana and Kristen Hogan, belie the veracity of his bold assertion. Despite the nature of their conjoined brains, the twins are not a massive financial burden to society and require only a modest regimen of anti-seizure medication --tantamount to the anyone else who may be prescribed medication. While, the courage of those who dare to be the Devil's advocate is admirable in some cases, regardless of the frugal motives behind his utilitarian argument- he has clearly assigned too low of a value to human life.
The second, and perhaps the most compelling assumption, is that such births represent an "inhumane cruelty." Clearly, Dr. Walker has never interacted with such individuals. Despite their striking disability, craniopagus twins have normal intelligent minds. The Bijani sisters, who studied law in Iran -an impressive achievement for anyone --conjoined or not-- were described as "a single unit albeit with diverse personalities." (Khan, 2005) The fact that the condition places a burden on society is not enough of a reason to terminate birth. Would you terminate a blind child's life? Or one with down syndrome? Stephen Hawkings is far more disabled than Dr. Walker, but I wonder who has accomplished more?
Allowing a physician, who may have the best of intentions, from taking the life of a child from its mother is an "inhumane cruelty" intolerable above all others. For this reason, the decision to terminate birth should be left to the mother --not to a physician-- as it may have been in Spartan times.
Rather than termination, such dramatic cases are strong impetus for the development of advanced surgical techniques. Indeed, there have been recent reports of successful separation operations, most under the hands of the talented John Hopkins neurosurgeon, Ben Carson. Dr. Carson, who's personal story is only matched by his phenomenal clinical feats, pioneered the use of cardiovascular surgery techniques, such as inducing cardiac arrest to prevent craniopagus patients from exsanguinating (bleeding to death) while undergoing separation surgery. To understand why exsanguination is so common, look at these images from Goh (2004).
From L-R: MR venogram image of the shared superior sagittal sinus, 3D CT of the twins’ cranium, Sagittal MRI of the twins’ brains. (Goh, 2004)
The venous architecture of craniopagus twins is extremely complex and highly intertwined, and the work of pumping all that blood is shared -sometimes unequally- between the two hearts. A detailed account of the separation procedure is documented in Goh (2004). In deciding if the twins could be separated, the multidisciplinary team of "neurosurgeons, plastic surgeons, anaesthetists, paediatricians, neurologists, a geneticist, dietician and physical, speech and occupational therapists" considered three main points: "(1) Were the brains separate? (2) Were the arterial and venous systems separate? (3) Could the resulting defect be closed?" Despite the daunting task of separating all of the vessels, the surgery is possible and the case presented below ended successfully for both twins.
I'll leave you with the conclusion written in Goh (2004): "Separation of craniopagus twins is technically possible, but demands extraordinary efforts from a large team of experienced and skilled personnel in the preoperative, operative and postoperative stages. Despite the advanced state of technology and knowledge available today, the complexity and rarity of this congenital malformation precludes a good outcome in all cases and will continue to present a formidable challenge to the medical field."
References:
Walker, K. (2007). The tragedy that should never have happened. Canadian Medical Association Journal, 177(3), 312. doi:10.1503/cmaj.070878
Khan, Z. H. (2005) Separated but oceans apart and fathoms deep: the conjoined twins’legacy. Singapore Medical Journal, 7(46), 363.
Goh, K. Y. C. (2004). Separation surgery for total vertical craniopagus twins. Child's Nervous System, 8(20), 567-575, doi:10.1007/s00381-004-0978-3
