Innovation in Surgical Technique
The Story of Spine Surgery
Robert B. Winter, MD

Innovations in spine surgery date back to the late nineteenth century when sterile surgery and anesthesia made progress possible. Were these advancements always done within the framework of ethical behavior, or were patients placed at inappropriate risks just for the sake of change? How does a surgeon choose to do a new procedure? What inner questions must be asked before proceeding? How much training is necessary, and from whom? How do we know when a new innovation is valid? In reality, these and other questions have faced us in the past. A review of historical process gives answers as to how we should behave in the future

Spine surgery, similar to all branches of the surgical profession, has evolved for many years to reach where it stands today. We are proud of this current state of expertise, but we also are aware that our profession will continue to progressively evolve. We now are asking ourselves as to how we evolved within the framework of ethical human behavior. Have we always followed the primary ethical motto "Primum Non Nocere"?

Historical Beginnings

One convenient starting point would be to go back 100 years to 1900 and establish what spine surgery consisted of at that time. Decompressive laminectomy had been performed for many years, but only for the most essential of reasons, bone fragments pushed into the spinal canal by trauma of some kind. Anterolateral decompression for Pott's disease also was well established

Just 13 years before, in 1887, W.F. Wilkins of Kansas had done the first internal stabilization of a spinal deformity using carbolised silver wire around the pedicles. It is ironic that the first open reduction of a spinal deformity was done by pedicle fixation. Hadra of Galveston TX, often is credited with this technique, but he clearly gives reference to Wilkins.

In 1911 Hibbs and Albee of New York City (at separate institutions), described posterior arthrodesis for Pott's disease. How did they come up with this idea? What gave them the courage to do such a procedure despite crude anesthesia, a lack of a blood bank, and lack of antibiotics?

As noted by Hibbs, the inspiration for creating a surgical ankylosis of the joints of the spine came from the benefits he had observed in performing arthrodesis of the knee. The total elimination of motion in the joint had a positive effect on the activity of the tuberculous infection.

This was a direct application of surgical findings in one articulation toward an improvement in surgical technique in another. It was not "guess-work". In view of the well known dire consequences of progressive kyphosis with paraplegia and death (known natural history), no one today would criticize these pioneers for subjecting their patients to an "experimental" procedure.

Should these pioneers have set up a prospective controlled clinical trial? Because such a concept did not exist at that time, of course not. First, they had to prove that surgical arthrodesis of the spine was technically possible, and the next step might have been to see whether such arthrodesis had a positive effect on patients with Pott's disease.

There is a considerable moral dilemma in setting up clinical trials in medicine, especially when the set-up is treatment versus non-treatment. This is not a problem when the condition being studied is benign, such as headache. One can easily study a new medicine in 100 patients and study a placebo in another 100 patients, and not feel much guilt about the discomfort suffered by the control group. However, when the consequences of nontreatment might be severe disability or even death, one cannot in good faith (good morality?, good ethics?) subject the control group to bad outcomes.

Because arthrodesis of the spine in its early days is the focus of the current paper, its subsequent progress must be examined. Posterior spinal arthrodesis for scoliosis began with Hibbs in 1914 and it was a logical extension of his work with Pott's disease. Although there were improvements in casting with the turnbuckle cast and later the Risser localizer cast, the arthrodesis itself changed little until 1960.

In 1960, a true innovation, arthrodesis using Harrington rods, was developed. Although Hatrington instrumentation was not the first metallic internal device for spinal deformity, it was the one that succeeded.

In terms of ethics or morality, we need to examine this innovation in two contexts, one being that of the inventor, Dr. Paul Harrington, and the other being all the other scoliosis surgeons who were interested in this new technique. Dr. Harrington worked at a rehabilitation hospital in Houston, TX, where a large number of patients with poliomyelitis were treated. Many of the patients had scoliosis develop. In many of these patients, the scoliosis was severe and life threatening. Traditional treatment was by posterior arthrodesis and correction in a turnbuckle cast. Although good radiologic corrections could be achieved, the frail chest of a patient with poliomyelitis could be pushed in, severelv reducing the already impaired pulmonary function. Pseudarthrosis rates were high and reoperations were fiequent.

Dr. Harrington thought that if internal correction and stabilization could be achieved, then these lethal effects of poliomvelitis scoliosis and its treatment could be prevented. If Dr. Harrington was embarking on his innovation today, in the year 2000, the Food and Drug Administration would require him to file an Investigational Device Exemption, and probably would require him to do a matched series of 200 patients; 100 patients who were treated with rods and arthrodesis and 100 patients who were treated only with arthrodesis and application of a cast.

This sounds very morally and ethically proper, but if a few of the patients who were not treated with rods died because of their turnbuckle casts, and none of the patients who were treated with rods died, how can we morally and ethically justify this "experiment"? Because the natural history of turnbuckle casting after spinal arthrodesis already was known, it is not necessary to repeat it, but rather to use it as a historical control.

Dr. Harrington did not just begin inserting metal rods into patients. He studied the anatomy carefully; he worked for 10 years with engineers from Baylor University, and did not release the rods for general use until he had spent all those years perfecting them. His patients who were treated early were well informed that this was a new idea. They were proud to be part of history.

What about those other spine surgeons who wished to use this new technique, arthrodesis with Harrington rods? What is the ethical way to approach such a new innovation? Does the surgeon just look at these new things and say "I can do that; let's schedule a few patients" or does the surgeon say "I'm interested in learning how to use these new things. I better go down to Houston and scrub in with Dr. Harrington on a few cases?"

Obviously. it would be better for the surgeon to go to Houston and scrub in with Dr. Harrington than to just "go it alone". However, what constitutes an adequate learning experience with Dr. Harrington, one case, two cases, a day, a week, a month, 3 months? Dr. Harrington would be in a much better position to know what constitutes an adequate learning experience than the surgeon scheduling the trip.

Another problem with such a "milestone" innovation is Dr. Harrington's time and endurance. How many visiting surgeons can he justify in the operating room at one time? Should he "go on the road" to spread the news or should he stay in Houston and let the world come to him?

Whom should Dr. Harrington let come to Houston? Should it be only experienced scoliosis surgeons doing full-time spine surgery? Should it be orthopaedic surgeons doing at least 50% of their practice in scoliosis surgery? Should it be any interested orthopaedic surgeon?

My personal experience is, I think, relevant. My chief (I was a second year resident in 1960) was Dr. John Moe, a very influential surgeon who devoted approximately all of his practice to treating patients with scoliosis. He went to Houston, scrubbed in with Dr. Harrington, and came back with knowledge and enthusiasm for this new innovation. He did, however, make one mistake; he did his first surgery on a patient with a 100º deformity secondary to myelomeningocoele. The patient developed a severe wound infection and died.

Dr. Moe learned from this mistake of trying a new technique on the most difficult of patients, and 3 months later (August 1960), he invited Dr. Harrington to come to the Twin Cities to operate on three patients: two with straightforward thoracic idiopathic scoliosis, and one with a severe myelomeningocoele scoliosis. After that he was "off and running" in the use of Harrington rods. I was the resident on one of those first patients with idiopathic scoliosis, so I became familiar with the Harrington technique early in my career.

Dr. Moe had a staggering amount of knowledge about the spine and scoliosis; he developed a superior technique of arthrodesis with facet joint fusion and abundant iliac crest bone grafting. He was a master at cast application. He saw the advantage of the rods as a supplement to the basic fusion technique and cast program that he already developed, an insight that many others failed to appreciate, substituting rod insertion for good arthrodesis technique and good postoperative casting. Harrington rods were an innovation of technology and an innovation of technique. The technique of spinal arthrodesis did not change but a technology was added; a supplement but not a replacement.

So far I have concentrated on advances in scoliosis surgery, but the original discussion was on the new concept of spinal arthrodesis. The original arthrodeses all were posterior but what about anterior interbody fusion? Most modern spine surgeons will quote the classic works of Hodgson in the 1950's as the beginning of anterior spine surgery, but they would be wrong. The classic anterior transthoracic debridement of infected and necrotic elements, and anterior strut grafting had been described 26 years earlier by Ito et al. The "innovation" of anterior arthrodesis was not so new after all. The Japanese surgeons were not successful, not because of their surgery, but rather because they did not have the advantage of streptomycin and other antituberculous antibiotics that were available to Hodgson.

Did Hodgson (or Ito and coworkers) have ethical dilemmas in attempting anterior spinal arthrodesis? First, there was no new technology, only an issue of technique. Second, anterior interbody fusion had been done since the early 1920s by such pioneers as MacLennon (1922) of Glasgow, and Royle (1921) of Australia. The only difference between Ito's and Hodgson's work and these earlier pioneers was the intrathoracic approach rather than the extraperitoneal flank approach to the lumbar spine or costotransversectomy. Therefore this was an advancement in thoracic surgery, in keeping with the extensive training in general surgery experienced by orthopaedic surgeons of that era. Hodgson was a fully qualified general surgeon before he began practicing orthopaedics. This also was true of Royle and MacLennon. The ethical "barrier" that many of us would perceive for embarking on an anterior interbody arthrodesis was in fact only of minor consideration for these surgeons who were experienced in exposing the front of the spine for other reasons.

When anterior spine surgery really "came of age" was in the mid I 960s through the work of Hodgson et al in Hong Kong. Dr. Kenneth Leatherman of Louisville was one of the first American surgeons to travel to Hong Kong and "learn from the master".

Dr. Moe was very impressed with what anterior spine surgery could do in helping his program, especially for patients with major kyphotic problems such as congenital, neurofibromatosis. dwarfing disorders, and Scheuermann's disease. In preparation for his first case, an achondroplastic dwarf with a I I0º thoracolumbar kyphosis and paraparesis, he went to the Universitv's cadaver lab with a well-trained cardiovascular surgeon and practiced anterior spine surgery. This was an ethicallv appropriate way to approach a new technique. At this point anterior surgery had nothing to do with technology. Because Dr. Moe was well aware of the 100% pseudoarthrosis rate when attempting posterior arthrodesis for these severe kyphoses, there was little ethical dilemma for him to proceed using the anterior approach

Current Dilemmas

In 1963, Raymond Roy-Camille of France was the first surgeon to internally stabilize a spine with two steel plates and screws in the pedicles. The patient was a woman with an extremely unstable fracture-dislocation and complete paraplegia. As a well~trained general and orthopaedic trauma surgeon accustomed to fixing unstable long bone fractures with plates and screws, this technologic advance was merely the application of well-known technology to a different bone. It was an advance in technique, not technology.

Roy-Camille's advancement was hampered by two problems, the fixed distance between the holes in the plate, and the lack of fixed connection between the screws and the plate. Both of these problems were addressed by Steffee who modified the plates and screws to permit variable screw position and rigid connection of the screws to the plates. Steffee's plate actually was safer than Roy-Camille's because the screws could always be centralized in the pedicles.

Thus begins one of the most bizarre episodes in the history of spine surgery. This marvelous advance in spine surgery technique (not technology), the use of pedicle screws and plates, was subjected to governmental bureaucracy appropriate for a new drug or a new implant such as a cardiac pacemaker. The bureaucracy approached the problem as a new technologv, which it was not. Plates and screws had been used for 50 years in every other bone in the body. The chemistry of stainless steel was not new and was not an issue.

The issue was the risk, particularly to nerve tissue, of the insertion of pedicle screws. The risk of neurologic injury has nothing to do with the screw; it is solely the function of the technical skill of the surgeon. It is a purely technical issue; not a technology issue.

How then should the surgeon desiring to use pedicle screws ethically approach this new technical issue? Similar to Dr. Moe or Dr. Leatherman approaching the issue of anterior spine surgery technique, the surgeon must carefully study the anatomy and preferably practice on a cadaver. It is also wise to scrub in with an expert. In May I984, I invited Dr. Steffee to come to Minnesota and demonstrate and teach this new technique in two patients. By the end of 1993, our group had inserted 4790 pedicle screws during 915 operative procedures. Postoperative nerve root irritation was seen with 11 screws (0.2%), but only three of these were associated with permanent root problems (0.06% of the screws inserted). This series has been published recently bv Lonstein et al.

All the surgeons were well trained, all did only spine surgery, and all had extensive experience. No patient left the operating table without radiologic proof of screw position. Intraoperative radiographs with pedicle markers or direct pedicle visualization were used whenever there was doubt.

These are all technical details available to all surgeons. Most of the problems I have seen from the work of other surgeons have been attributable to a "cavalier" attitude and lack of attention to small details.

The ethics of the use of pedicle screws is not a governmental issue, but rather an issue of the skill of the surgeon. The patient should be advised that nerve root injury is possible, but the incidence is very low if the surgeon is highly skilled and careful

Future Developments

The story of the development of new techniques in scoliosis treatment is the story of virtuous men, dedicated to the welfare of their patients, who constantlv strive to lessen the patients deformities and improve the quality of their lives. Improvement seldom came in huge leaps, but rather by dogged persistence that nibbled away at the frontiers of ignorance. Sometimes the surgeons made mistakes, but because they were good persons, they did everything in their power to learn from their mistakes and to let the world know what to do and what not to do. They may not have had any formal training in ethics, but they were ethical.

Recently, the demand by some for placebo-controlled surgical procedures resulted in a clinical experiment for Parkinson's disease. Burr-holes were made in the skull (bilateral) with the patients under general anesthesia. Fetal tissue was inserted into the brain in 1/2 of the patients and the other 1/2 of patients were the controls. Although Freeman et al made an attempt to justify the procedure scientifically and ethically, Macklin stated that such sham surgery was ethically unacceptable.

Should a sham operation be done to evaluate the benefit or lack of benefit for low back fusion for spondylolisthesis? Of course not; it's a ridiculous idea, because the answers we want can be found by ethical studies

Because our profession is always in a state of advancement, how do we ethically deal with the new ideas that come along? Not all new things are good, the use of Cotrel traction, the halo-hoop, and electrical muscle stimulation in the nonoperative treatment of scoliosis being outstanding examples of useless and even dangerous procedures in the past 30 years.

We now are being deluged with a flood of methods to treat painful discs, to accelerate bone healing, and to preoperativelv evaluate patients for surgery. The ethical surgeon is going to listen carefully and then wait for proof. In a recent study, a new method for lumbosacral fusion was proposed; all 11 patients achieved solid fusion (100% success) whereas one of the three control subjects (the old method) did not achieve solid fusion (66.6% success). This control group of three patients is an absolutely useless piece of statistics, which the ethical surgeon will ignore. Statistics emanating from a surgeon who is being paid by the company to promote a device or substance always are suspect. The ethical surgeon will wait for independent evaluation,

There are many ethical dilemmas in spine surgery and it appears the problem will only increase in time with the development of new techniques and technology. Fortunately, there are well-established patterns of behavior, which allow steady progress with a minimum of patient harm.