Sham surgery
Sham surgery (also placebo surgery) is a faked operative intervention that omits the step thought to be therapeutically necessary. In controlled studies sham surgery is performed in the control population to assess the effect of the intervention under study by neutralizing the placebo effect and reducing bias. Contrary however to a placebo, typically exemplified by the inert "sugar pill", sham surgery involves a real surgical intervention to compensate for the effect of anesthesia, the incisional trauma, and pre- and postoperative care and to maintain the illusion of a regular operation. Thus sham surgery has an inherent risk and conflicts with the ethical principle of primum non nocere.
Human research
The placebo-controlled trial is the gold standard of medical research.[1] Therefore, when testing results of a surgical procedure, sham surgery serves as the intervention in the control population. However, the use of sham surgery in human research is controversial[2] as it places high ethical and high research standards into conflict.[1] Such surgery has the potential to harm the subject, however, alternative research designs without sham surgery are scientifically less rigorous. Proponents argue that surgical interventions need to be tested as critically as medical interventions.[1] Because of the ethical concerns, sham-operated controlled studies are rarely performed in humans.[3]
A number of studies done under IRB approved settings have delivered important and surprising results. With the progress in minimally invasive surgery sham procedures can be more easily performed as the sham incision can be kept small similarly to the incision in the studied procedure.
Examples
In a number of situations, sham-controlled interventions have identified interventions that are useless but had been believed by the medical community to be helpful based on studies without the use of sham surgery. Thus in 1939 Fieschi introduced internal mammary ligation as a procedure to improve blood flow to the heart. Not until a sham-controlled study was done two decades later could it be demonstrated that the procedure was ineffective.[2][4] In neurosurgery, cell-transplant surgical interventions were offered in many centers in the world for patients with Parkinson disease until sham-controlled experiments involving the drilling of burr holes into the skull demonstrated such interventions ineffective and possibly harmful.[5] Subsequently over 90% of surveyed investigators believed that future neurosurgical interventions (ie. gene transfer therapies) should be evaluated by sham-controlled studies as these are superior to open-control designs, and half found it unethical to conduct an open-control study because the design is not strong enough to protect against the placebo effect and bias.[5] Kim et al. point out that sham procedures can differ significantly in invasiveness, for instance in neurosurgical experiments the investigator may drill a burr hole to the dura mater only or enter the brain.[5]
In a classic experiment in orthropedic surgery Moseley and coworkers studied the effect of arthroscopic surgery for osteoarthritis of the knee establishing two treatment groups and a sham-operated control group.[6] They found that patients in the treatment arms did no better than those in the control group. The fact that all three groups improved equally points to the placebo effect in surgical interventions.
Ethical considerations
While some ethicists reject sham-surgery in controlled trials,[1][7] others maintain that such trials are ethically acceptable but should conform to certain restrictions.[3][8][9][10] Such restrictions include that the research question is important and cannot be answered by other forms of research, further the risk of the sham procedure should be kept as minimal as possible and the informed consent needs to be appropriate with subjects being aware of the risks and that they may receive placebo surgery.[8][11]
Animal research
Sham surgery has been widely used in surgical animal models. Historically, studies in animals also allowed the removal or alteration of an organ; using sham-operated animals as control, deductions could be made about the function of the organ. Sham interventions can also be performed as controls when new surgical procedures are developed.
References
Cite error: Invalid <references> tag;
parameter "group" is allowed only.
<references />, or <references group="..." />- ↑ 1.0 1.1 1.2 1.3 Macklin R (September 23, 1999). "The Ethical Problems with Sham Surgery in Clinical Research". New England Journal of Medicine 1999;341:992-6. 341 (13): 992–6. doi:10.1056/NEJM199909233411312. PMID 10498498.
- ↑ 2.0 2.1 Stolberg SG (April 25, 1999). "Sham Surgey Returns as a Research Tool". The New York Times. Retrieved May 1, 2009.
- ↑ 3.0 3.1 Albin RL (October 1, 2002). "Sham surgery controls: intracerebral grafting of fetal tissue for parkinson's disease and proposed criteria for use of sham surgery controls". Journal of Medical Ethics. 28 (5): 322–5. doi:10.1136/jme.28.5.322. PMC 1733639 Freely accessible. PMID 12356962.
- ↑ Cobb LA, Thomas GI, Dillard DH, Merendino KA, Bruce RA. (1959). "An evaluation of internal-mammary-artery ligation by a double-blind technic". New England Journal of Medicine 1959; 260:1115-8. 260 (22): 1115–8. doi:10.1056/NEJM195905282602204. PMID 13657350.
- ↑ 5.0 5.1 5.2 Kim SYH, Frank S, Holloway R, Zimmerman C, Wilson R, Kieburtz K (September 2005). "Science and Ethics of Sham Surgery. A Survey of Parkinson Disease Clinical Researchers". Arch Neurol 62:1357-60. 62 (9): 1357–60. doi:10.1001/archneur.62.9.1357. PMID 16157742.
- ↑ Moseley JB, O'Malley K, Petersen NJ, Menke TJ, Brody BA, Kuykendall DH, Hollingsworth JC, Ashton CM, Wray NP (2002). "A controlled trial of arthroscopic surgery for osteoarthritis of the knee". New England Journal of Medicine 2002;347:81-8. 347 (2): 81–8. doi:10.1056/NEJMoa013259. PMID 12110735.
- ↑ Dekkers W, Boer G. (2001). "Sham neurosurgery in patients with Parkinson's disease: is it morally acceptable?". J Med Ethics. 2001 ;27(3):151-6. 27 (3): 151–6. PMC 1733414 Freely accessible. PMID 11417020.
- ↑ 8.0 8.1 Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
- ↑ Tenery R, Rakatansky H, Providence RI, Riddick FA Jr, Goldrich MS, Morse LJ, O'Bannon JM III, Ray P, Smalley S, Weiss M; et al. (2002). "Surgical "Placebo" Controls". Annals of Surgery: 2002; 235:303-307. 235 (2): 303–7. PMC 1422430 Freely accessible. PMID 11807373. Retrieved May 2, 2009.
- ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
- ↑ Mehta S, Myers TG, Lonner JH, Huffman GR, Sennett BJ (2007). "The Ethics of Sham Surgery in Clinical Orthopaedic Research". The Journal of Bone and Joint Surgery 2007;89:1650-53. 89 (7): 1650–3. doi:10.2106/JBJS.F.00563. PMID 17606805.
