Each month during the coming year, OrthoBuzz will bring you a current commentary on a “classic” article from The Journal of Bone & Joint Surgery. These articles have been selected by the Editor-in-Chief and Deputy Editors of The Journal because of their long-standing significance to the orthopaedic community and the many citations they receive in the literature. Our OrthoBuzz commentators will highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation about these classics by clicking on the “Leave a Comment” button in the box to the left.
The JBJS Classic Treatment of Scoliosis: Correction and Internal Fixation by Spinal Instrumentation by Paul R. Harrington describes 15 years of investigation, beginning in 1947, soon after Dr. Harrington completed his residency in Kansas City and headed an Army orthopaedic unit during World War II. The importance of this paper can’t be overstated. With this description of instrumentation that improved deformity outcomes, Harrington ushered in modern spine surgery. It was also one of the rare early examples of orthopaedic clinical science funded by a national grant.
The need for this daring, revolutionary instrumented approach was the polio epidemic, which left Dr. Harrington caring for many patients with severe, collapsing curves that threatened their health. Polio patients comprised 75% of the first series described in this paper.
This comprehensive study combines theory, basic science, surgical techniques, and outcomes. With it, Harrington started the still-continuing dialogue about indications for scoliosis surgery with the comment that “clinical indications for therapy are still being worked out.” As a partial answer to the indications quandary, he introduced the Harrington factor—the number of degrees of primary curve divided by the number of vertebrae in the primary curve. This calculation continues to be used (renamed) in some current research into risks of curve correction, while debate continues about other indications such as progression, pain, and pulmonary issues.
The technique of spinal instrumentation is extensively described in this landmark article. Noteworthy is Harrington’s gradual embrace of the need for fusion and well-molded body cast immobilization, both of which he credits with improved results. (Initially Harrington had hoped to avoid fusion in many cases.) Although “instrumentation” today is nearly synonymous with “fusion,” some of our most promising ideas in deformity correction now involve instrumentation without fusion.
Also impressive is the respect with which Harrington treated the spinal cord and dura. He describes careful insertion of the hooks and recommends against downward hooks above L2, where the conus ends. This paper reminds us that we should always pursue the lowest-risk approach to instrumentation that will serve our patients. Dr. Harrington was also cognizant of the importance of blood loss, and meticulously measured it by stage of surgery. He showed that most blood loss occurred during subperiosteal dissection, a fact that we still recognize today.
Harrington’s description of selective thoracic fusion was illustrated radiographically in Figure 7, which shows a dramatic result where a 55° unfused lumbar curve declined to 18° after correction of a larger thoracic curve. This concept was further developed by Moe, King, Lenke and others, but the idea of spontaneous correction of lumbar curves started with the power of Harrington’s instrumentation.
The benefits of our more “modern” instrumentation are evident when reading the recommended aftercare in Harrington’s paper: a 16-day hospital stay, 8 weeks of bed rest, and a Risser localizer cast for 3 to 5 months, only to find out whether the patient might need reoperation for instrumentation problems or pseudarthrosis.
A modern journal editor might have expended some red ink on Dr. Harrington’s paper. The organization was less formal than many scientific papers today, but this may reflect the multiple simultaneous investigations and changes that took place during this decade-plus of revolutionary work. Dr. Harrington emphasizes that the results improved with each iteration of the procedure and device, which underwent more than three dozen design modifications.
Details on the curve sizes were not given, but we now recognize that curve size does not correlate linearly with clinical parameters. While Harrington does not describe the contributions of others who may have been involved in this work, neither does he use the eponymous term (“Harrington instrumentation”) that others attached to his spinal fixation device. While remarkable in its prescience, this paper did not anticipate the problems of distraction instrumentation in the lumbar spine, later characterized as Flatback Syndrome. It also did not elaborate on the need for differing mechanics in kyphoscoliosis or Scheuermann kyphosis.
Nevertheless, in this single article, Dr. Harrington laid the groundwork for three major themes that orthopaedists have further developed:
- The safety and benefits of metal fixation in spine surgery
- The use of growth guidance in patients < 10 years old
- The idea of selective thoracic fusion for double curves
Each of these ideas has generated hundreds of additional studies and papers to get us to modern practice. Just as current hip arthroplasty techniques represent incremental improvements on the monumental contribution of Charnley, current techniques in scoliosis surgery, especially of the thoracic spine, are but stepwise improvements on Harrington’s classic work.
Paul Sponseller, MD, JBJS Deputy Editor for Pediatrics
Marc Asher, MD, Professor Emeritus, Department of Orthopaedic Surgery, University of Kansas Medical Center
Orthopaedic surgical procedures to correct axial and appendicular skeletal deformities are usually dependent upon fixation devices, either external or internal or both. These devices are often developed through close collaboration with engineers who are generally employed by major manufacturing companies. After the devices successfully clear rigorous bench, in-vitro, and in-vivo testing, the standard initial presentation of clinical results is a case series.
All too often the initial report of results comes from a co-developer of the device, with inherent selection and detection bias that constitute what most readers would consider a conflict of interest. McCarthy and McCullough’s case series on five-year results with Shilla growth guidance in 33 children with early-onset scoliosis in the October 7, 2015 JBJS is an exception to that rule. The authors report every conceivable major and minor adverse event without holding back any negative information. They categorize complications as infection secondary to wound breakdown, spinal alignment issues, and implant issues. The overall complication rate was 73%, a rate that is not surprising given the fact that the device under study is designed to maintain correction of spinal deformity in growing children.
Thankfully, the authors reported no neurologic complications. Also on the positive side, they found that spinal curves averaging 69° preoperatively averaged 38.4° at the most recent follow-up or prior to definitive spinal instrumentation. McCarthy and McCullough also calculated a 73% reduction in the number of surgical procedures among their cohort, relative to what would be necessary to treat the same population with distraction methods every six months.
I applaud the authors for comprehensively reporting the results of correction of spinal deformity in this difficult clinical situation with high accuracy and strict definitions of major and minor events. This is how we will make advances in correcting deformity for skeletally mature and immature patients—with innovation, incremental improvement, and the widespread sharing of adverse events with the orthopaedic community. Armed with the information from this study, we must now see what the number and severity of complications look like when the broader community of orthopaedic surgeons applies these devices.
Marc Swiontkowski, MD
One benefit of our digital age is that it allows virtually real-time “conversations” to be published between authors of orthopaedic studies and their colleagues, without the lag time imposed by print.
Case in point is the engaging back-and-forth between James Sanders, MD (co-author of the April 16, 2014 JBJS study titled “Bracing for Idiopathic Scoliosis: How Many Patients Require Treatment to Prevent One Surgery?”) and Hans-Rudolf Weiss, an orthopaedic surgeon from Germany.
The original study found that bracing for idiopathic adolescent scoliosis substantially decreased the risk of curve progression to a surgical range—but only when patients wore the brace at least 10 hours a day. Among those “highly compliant” patients, the number needed to treat to prevent one surgery was 3. However, only 31% of the 126 subjects in the study were highly compliant. The authors also noted that current bracing indications include many curves that would not have progressed to surgical range even if the patient had not worn a brace.
In an eLetter (click on the “eLetters” tab under the article citation), Dr. Weiss stressed that patient compliance with bracing is largely influenced by the physician, but that half of the members of the Scoliosis Research Society do not believe in bracing. He additionally suggested that the findings pertain to the brace designs used in the study and may not be generalizable to other brace types. Dr. Weiss concluded that “long-term corrections can be achieved when recent bracing standards are applied.”
In a response to Dr. Weiss’s eLetter, Dr. Sanders suggested that the recent publication of the BrAIST study, which provided high-level evidence that bracing can prevent progression to a surgical range, has bolstered the ranks of bracing “believers” among orthopaedists. Despite that, Dr. Sanders points out that even strong physician proponents of bracing are “likely to have patients for whom bracing is unacceptable and their compliance poor.” That fact, he says, “makes it our imperative to develop bracing which is effective while still being both comfortable and psychosocially acceptable to patients.”
Every month, JBJS publishes a Specialty Update—a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Here is a summary of selected findings from Level I and II studies cited in the February 18, 2015 Specialty Update on pediatric orthopaedics:
–The landmark BrAIST study found that bracing helps prevent adolescent idiopathic scoliosis curves from progressing to a surgical range (≥50°), with a number needed to treat of 3. (See related OrthoBuzz article.)
–A randomized trial comparing the SpineCor brace to rigid bracing for correction of scoliosis found that the rate of curve progression was significantly higher in the SpineCor group.
–A study on the role of steroids in patients with Duchenne muscular dystrophy found that glucocorticoid therapy decreased the need for spinal surgery to treat scoliosis.
–A randomized trial among patients 4 to 12 years of age with a distal radial or distal both-bone fracture found that the use of a double-sugar-tong splint for immediate post-reduction immobilization was at least as effective as the use of a plaster long arm cast.
–A randomized controlled trial of 61 patients from 5 to 12 years old who had a supracondylar humeral fracture found no functional or elbow-motion benefits associated with hospital-based physical therapy after short-term casting.
Foot and Ankle
–A randomized trial of 27 children less than 9 months of age who had resistant metatarsus adductus found that a group receiving orthotic treatment had greater improvement in footprint heel bisector measurements than those receiving serial casting. The orthotic program required more active parental participation but was about half the cost of casting.
–A randomized study of children under 3 months of age with idiopathic clubfoot who were treated with the Ponseti method found that the failure rates and treatment times were significantly higher in a below-the-knee casting group than in an above-the-knee casting group.
The Orthopaedic Research and Education Foundation (OREF) has bestowed its 2015 Clinical Research Award on Stuart Weinstein, MD, professor of orthopaedic surgery at the University of Iowa Hospitals & Clinics and former chair of the JBJS Inc. Board of Trustees.
Dr. Weinstein and his co-investigator Lori Dolan, PhD were recognized for a lifetime of clinical research into adolescent idiopathic scoliosis (AIS). Decades of their work culminated in the landmark BrAIST trial, a randomized/preference-cohort study that compared bracing to watchful waiting in 242 patients with AIS. That study found a treatment success rate of 72% in the bracing group, compared with a rate of 48% in the watchful-waiting group. BrAIST delivered Level I evidence that bracing can substantially reduce the risk of curvature progression to the surgical threshold of 50° or greater, and it has already started to change the way pediatric orthopaedists practice.
“Our research….has given patients and parents a solid evidence base upon which to make informed, patient-centered choices,” Dr. Weinstein told AAOS Now recently.
Baylor University basketball star Isaiah Austin was 20 years old when the NBA told him last month that he had Marfan syndrome and was ineligible to play professional basketball. Why was Austin not diagnosed with this potentially fatal connective-tissue disorder earlier in life? The answer may lie in a 2010 study by Sponseller et al. in JBJS. The authors point out that early diagnosis of Marfan syndrome is complicated by the fact that many of its recognizable skeletal features—including scoliosis and flat feet—appear with some frequency in the general population.
By studying people with confirmed Marfan syndrome and those without, the authors discovered that the most diagnostically relevant physical characteristics of the syndrome are craniofacial features such as narrow cranial shape and positive thumb and wrist signs. The combined presence of those characteristics yielded an area-under-the-curve diagnostic accuracy of 0.997. Doctors often recommend that people with suspected Marfan syndrome receive confirmatory genetic tests, which are readily available but expensive.
Even though it’s difficult to recognize Marfan syndrome on the basis of physical observation alone, Sponseller et al. suggest that orthopaedists “at least briefly visualize the entire patient” and consider a referral for genetic testing and/or echocardiogram when the aforementioned features are present.
For his part, Mr. Austin took the news in stride. He said he plans to return to Baylor to finish his degree and perhaps become a Marfan syndrome advocate-educator. His inspiring Instagram message: “Please do not take the privilege of playing sports or anything for granted.”
How to prevent pulmonary function deterioration has been a focus in the management of boys with Duchenne muscular dystrophy (DMD) for many years. Since the 1980s it has been thought that an increasing scoliosis is associated with declining pulmonary function at a rate even greater than that from the effects of muscle weakness. As a result, it is common for surgery to be recommended for patients with DMD once a scoliosis of greater than 20 degrees is noted, a much lower threshold than is used for surgical treatment of idiopathic scoliosis. This practice assumes that surgical correction reduces the worsening of pulmonary function, but solid data to support that view has been absent.
The article “Functional Outcomes in Duchenne Muscular Dystrophy Scoliosis” in the March 5, 2014 JBJS confirms that surgical treatment of scoliosis in DMD does lead to better vital capacity, compared with no surgical treatment. However, before deciding that all DMD patients will need spine surgery to slow down pulmonary function worsening, surgeons should keep in mind the current efficacy of early treatment with corticosteroids to prevent scoliosis in this patient group. Not only does corticosteroid treatment prevent scoliosis development in the majority of kids, but the deterioration in pulmonary function is also slowed compared to those without this treatment.
With the information on pulmonary function provided in this article, we now have concrete data for use in discussions with parents on whether to select early treatment with corticosteroids to prevent scoliosis or to wait for surgical correction later. Surgery has risks associated with cardiac and pulmonary compromise inherent in DMD, and corticosteroids carry the risk of stunted growth and the development of cataracts in many patients. This article contributes useful hard data to enhance the process of shared decision making for the spinal care of children with DMD.