Sham surgery (placebo surgery) is a faked surgical intervention that omits the step thought to be therapeutically necessary. In

clinical trials Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, dieta ...

of surgical interventions, sham surgery is an important

scientific control A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable (i.e. confounding variables). This increases the reliability of the results, often through a comparison bet ...

. This is because it isolates the specific effects of the treatment as opposed to the incidental effects caused by

anesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...

, the

incision Incision may refer to: * Cutting, the separation of an object, into two or more portions, through the application of an acutely directed force * A type of open wound caused by a clean, sharp-edged object such as a knife, razor, or glass splinter * ...

al trauma, pre- and postoperative care, and the patient's perception of having had a regular operation. Thus sham surgery serves an analogous purpose to

placebo A placebo ( ) is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets (like sugar pills), inert injections (like Saline (medicine), saline), sham surgery, and other procedures. In general ...

drugs, neutralizing biases such as the

placebo effect A placebo ( ) is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets (like sugar pills), inert injections (like Saline (medicine), saline), sham surgery, and other procedures. In general ...

Human research

A number of studies done under Institutional Review Board-approved settings have delivered important and surprising results. With the progress in

minimally invasive surgery Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definitio ...

, sham procedures can be more easily performed as the sham incision can be kept small similarly to the incision in the studied procedure. A review of studies with sham surgery found 53 such studies: in 39 there was improvement with the sham operation and in 27 the sham procedure was as good as the real operation. Sham-controlled interventions have therefore 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.

Examples

Cardiovascular diseases

In 1939 Fieschi introduced

internal mammary In human anatomy, the internal thoracic artery (ITA), previously commonly known as the internal mammary artery (a name still common among surgeons), is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with one ...

ligation as a procedure to improve blood flow to the heart. Not until a controlled study was done two decades later could it be demonstrated that the procedure was only as effective as the sham surgery.

Central nervous system disease

In neurosurgery, cell-transplant surgical interventions were offered in many centers in the world for patients with

Parkinson disease Parkinson may refer to: * Parkinson (surname) * ''Parkinson'' (TV series), British chat show, presented by Sir Michael Parkinson * Parkinson, Queensland, suburb of Brisbane, Australia *The Parkinsons (fl. early 20th century), American father-and-so ...

until sham-controlled experiments involving the drilling of burr holes into the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...

demonstrated such interventions to be ineffective and possibly harmful. Subsequently, over 90% of surveyed investigators believed that future neurosurgical interventions (e.g. gene transfer therapies) should be evaluated by sham-controlled studies as these are superior to open-control designs, and have found it unethical to conduct an open-control study because the design is not strong enough to protect against the placebo effect and bias. 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 In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. ...

only or enter the brain. In March 2013
sham surgical study
of a popular but biologically inexplicable venous balloon angioplasty procedure for multiple sclerosis showed the surgery was no better than placebo.

Orthopedic diseases

Moseley and coworkers studied the effect of

arthroscopic surgery Arthroscopy (also called arthroscopic or keyhole surgery) is a minimally invasive surgical procedure on a joint in which an examination and sometimes treatment of damage is performed using an arthroscope, an endoscope that is inserted into the ...

for

osteoarthritis Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the ...

of the knee establishing two treatment groups and a sham-operated control group. They found that patients in the treatment group 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. In a 2016 study it was found that arthroscopic partial meniscectomy does not offer any benefit over sham surgery in relieving symptoms of knee locking or catching in patients with degenerative meniscal tears.Sihvonen R, Englund M, Turkiewicz A, Järvinen TL: Mechanical Symptoms and Arthroscopic Partial Meniscectomy in Patients With Degenerative Meniscus Tear: A Secondary Analysis of a Randomized Trial. Ann Intern Med. 2016 Feb 9 A randomised controlled trial was carried out to investigate the effectiveness of shoulder surgery to remove an acromial spur (bony protuberance on x-ray) in patients with shoulder pain. This found that improvement after sham surgery was as great as with real surgery. A systematic review has identified a number of studies comparing orthopedic surgery to sham surgery. This demonstrates that it is possible to undertake such studies and that the findings are important.

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

{{DEFAULTSORT:Sham Surgery Human subject research Deception Clinical research Ethically disputed medical practices Medical terminology Surgery