New surgical technology that offers the promise of improved patient care is attractive. Intrigued, and with an intuitive certainty, surgeons—cheered on by their patients—may adopt new technologies, despite little evidence of either their efficacy or their superiority over existing procedures. The argument that randomised clinical trials of surgical procedures are unethical because the new treatment is better than alternative treatment or no treatment is based on presumption more than fact, and arguments to the contrary are compelling.¹ Surgical procedures that are later found to be ineffective waste resources and endanger lives. Understanding why such procedures come to be offered as treatment can inform us—whether we are well intended perpetrators or unsuspecting patients.

New medical technology may come in the form of a drug, a device, a procedure, a technique, or a process of care. In surgery, innovation is generally either a new procedure that uses existing devices or drugs, such as chymopapain for lumbar disc disorders, or an existing procedure that uses new devices, such as those for spinal fusion.

Social observers have advanced pivotal theories regarding the adoption and diffusion of technologies. Everett Rogers described an S-curve portraying the diffusion of innovations and identified characteristics that act as drivers or barriers.² The diffusion of an innovation comprises five stages: the launch by innovators followed in successive stages by early adopters, the early majority, the late majority, and, finally, the laggards (figure). Malcolm Gladwell³ explains social change as the result of circumstances in which ideas, products, messages, and behaviours spread like viruses through “word-of-mouth epidemics” that are set in motion by three types of individuals: “mavens,” who gather information and pass it on to others; “connectors,” who are sociable and bring people together; and “salesmen,” who have a talent for persuasion.³ The speed of diffusion accelerates to a peak (the tipping point), which occurs on average at 20% adoption.

In 1964, Lyman Smith reported that injecting the enzyme chymopapain into an intervertebral disc relieved pain caused by herniation of the lumbar disc.¹⁰ By 1974, 17 000 patients were having chymopapain chemonucleolysis each year. In 1989, the American Medical Association's diagnostic and therapeutic technology assessment group questioned the efficacy of the procedure and raised concerns about its safety, citing rare but serious complications.¹¹ Their evaluation showed that, compared with placebo or no treatment, chymopapain was effective in only selected patients. In addition, when it was used by less experienced surgeons some patients incurred serious complications, including anaphylaxis and damage to the spinal cord.¹¹ Although these complications were rare, widespread attention in the media to the drawbacks of chymopapain chemonucleolysis and pressure from an informed public hastened general abandonment of the procedure by patients as well as surgeons. Some centres still use chymopapain as an interim treatment between exercise and surgery for patients with herniated discs, but it has been relegated to a niche procedure sustained by a small group of advocates.

In 1982, Romodanov and Shcheglov¹⁴ reported the first large series in which they treated intracranial aneurysms by intra-aneurysmal obliteration using a detachable balloon. The technique proved unsatisfactory, but pushable platinum coils were then introduced for the endovascular treatment of selected intracranial cerebral aneurysms. The platinum coil was supplanted in 1991 by the detachable coil,¹⁵ which established the promise of endovascular approaches. Endovascular treatment, however, was used almost exclusively for aneurysms that could not be treated surgically and for patients treated before their aneurysm had ruptured.

Any surgical technology that is avidly adopted and spreads rapidly without evidence of its comparative benefit runs the risk of being abandoned after objective examination. Instrumentation for spinal fusion has not been rigorously evaluated, and I believe that some of the current indications for its use will not be sustained and a yet to be reported randomised controlled trial will define clinical indications far more stringent than those used at present. The number of patients having spinal procedures is increasing, and the proportion of those who have some form of spinal fusion is increasing disproportionately. Spinal instrumentation is increasing by 20% a year in the United States, and the indications for operations using new instrumentation are often loosely characterised and flexible. The primary driver of spinal instrumentation is the industry that manufactures spinal devices, which runs workshops to teach surgeons how to use its products.

Before adopting a new technology, surgeons and institutions should carefully consider the questions in box 3. At what stage on the S-curve should they decide to adopt and implement a technology? Reasons to be an early adopter may be the surgeon's image, the culture of the institution, or a willingness to take a risk. However, those who are more conservative and sceptical may change only under pressure during the late majority stage. These characteristics may ultimately determine the adoption or rejection of a new surgical technology, but the precondition that is often forgotten in the excitement that comes with change is certainty that the new technology will improve the quality of clinical care for patients. If this precondition is not satisfied, the technology should be abandoned: even a logical and scientifically sound approach is no substitute for proof in practice.

Use of new surgical technology has the potential to provide patients with the best possible care while reinforcing the professional vitality of the surgeon and the institution, boosting their image, and providing a competitive advantage. Conversely, that decision also has the potential to sully reputations, waste resources, and cause inadvertent harm to patients. Surgeons and institutions must guard against “going with the tide” in adopting a technology without solid evidence of its efficacy and superiority over alternatives. In the final analysis, a surgeon's skill and ability to perform a procedure well is unimportant, in fact irrelevant, if the procedure should not be done in the first place.