Tag Archive | Spine

JBJS Classics: Harrington Ushered in Modern Spine Surgery in 1962

JBJS-Classics-logo

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

What’s New in Spine Surgery: Level I and II Studies

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 June 17, 2015 Specialty Update on spine surgery:

  • A database study to determine the prevalence of venous thromboembolic events after spinal fusion found that risk factors for such events included hypercoagulability, certain medical comorbidities, older age, and male sex.
  • An RCT comparing allograft alone versus allograft plus bone marrow concentrate to accomplish spine fusion in adults with spondylolisthesis found very poor union rates in both groups, although allograft with bone marrow concentrate delivered slightly better results.
  • A meta-analysis of five studies (253 patients) found no pain or functional differences when unilateral percutaneous kyphoplasty was compared with bilateral (same-vertebra) kyphoplasty for osteoporotic compression fractures. The unilateral approach was associated with shorter operative times, however.
  • An RCT comparing the analgesic efficacy and clinical utility of gabapentin, pregabalin, and placebo in patients undergoing spinal surgery found that pregabalin outperformed the other two interventions immediately after surgery postoperative and up to three months postoperatively.
  • In an RCT comparing open-door to French-door laminoplasty for cervical compressive myelopathy, both techniques were found to be equivalent in terms of neurological recovery and perioperative complications, but patients receiving the open-door technique had more kyphosis and less cervical range of motion postoperatively.
  • An update to a 2002 Cochrane review found no significant outcome differences between supervised and home-exercise rehabilitation programs after lumbar disc surgery.
  • A systematic review/meta-analysis showed that radiofrequency denervation of facet joints is more effective than placebo in achieving functional improvement and pain control in patients with chronic low back pain.
  • A Level II diagnostic study concluded that with a magnification of 150% and a good pair of flexion and extension radiographs following anterior cervical arthrodesis, pseudarthrosis was noted with >1 mm of motion between fused interspinous processes with 96.1% specificity and a positive predictive value of 96.9%.
  • A Level I therapeutic study comparing the efficacy of intravenous tranexamic acid, epsilon-aminocaproic acid, and placebo to reduce bleeding in 125 adolescent patients undergoing posterior fusion for idiopathic scoliosis found less intraoperative and postoperative blood loss and higher hematocrit levels with the antifibrinolytics than with placebo. However, transfusion requirements were no different between the groups.
  • A randomized comparison of navigated versus freehand techniques for pedicle screw insertion during lumbar procedures found that surgeon radiation exposure with freehand technique is up to 10 times greater than with use of navigation.

Hot Flashes Linked to Increased Risk of Hip Fracture in Women

Menopausal women who experience moderate to severe hot flashes are 1.78 times as likely to fracture a hip as women of similar age who don’t have hot flashes. Interestingly, the researchers, reporting in The Journal of Clinical Endocrinology & Metabolism, found no association between hot flashes and vertebral fractures. However, they did find that the more severe the hot flashes, the lower the women’s bone density at the femoral neck and lumbar spine.

None of the women studied were using hormone therapy to treat menopause at baseline, and very few started hormone therapy during the mean follow-up of 8.2 years. The findings include statistical adjustment for baseline age, BMI, smoking, and other variables.

Carolyn Crandall, MD, the lead author of the study, told the Washington Post that the reason for the hot flash-hip fracture connection is “entirely a mystery.” But the authors wrote that “our analysis does suggest that impaired physical functioning may partially explain the [hip-fracture] association.” They also surmised that lower estradiol levels in women with hot flashes may partly explain the association between hot flashes and decreased bone density.

What’s New in Primary Bone Tumors

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 studies cited in the December 17, 2014 Specialty Update on primary bone tumors:

Chondrosarcoma

–MicroRNA-145, an inhibitor of cell growth, was expressed at abnormally low levels in chondrosarcoma, lending credence to the hypothesis that underexpression of microRNA-145 plays a role in cancer development.

–Osteoclasts enhance the ability of chondrosarcoma to invade bone, but that invasion that can be partially halted by zoledronic acid.

–There is increased activity of the glycolysis-associated enzyme lactate dehydrogenase-A (LDHA) in chondrosarcoma.

–Density and location of new blood-vessel formation may be an important prognostic factor in chondrosarcoma.

–Conditional survival in patients with chondrosarcoma improves with each year of survival, but even patients who survive ten years after diagnosis cannot be considered cured.

Chordoma

–Variants of T transcription factor play a role in the pathophysiology of familial and sporadic chordoma.

–In patients with primary sarcomas of the spine, proton radiation plus surgery yielded local control rates of 85% at eight years.

Osteosarcoma

–Expression of the glucose transporter Glut-1 correlated with worse outcomes in patients with osteosarcoma.

–Secondary malignant neoplasms were found in 2.1% of long-term survivors of osteosarcoma.

–Use of fluorescence-guided surgery in a mouse model of osteosarcoma allowed reduction in the amount of residual tumor and improved disease-free survival.

–Among patients with high-grade osteosarcoma with soft-tissue extension, four parameters—tumor location, intracapsular extension, Huvos grade, and alkaline phosphatase level—may help predict which individuals will eventually develop metastases.

–In 45 patients with local recurrence but no metastases, the 10-year survival rate was 13%; most local recurrences were in soft tissue, not bone.

–Mid-therapy PET imaging may be useful to physicians in assessing response to chemotherapy.

Ewing Sarcoma

–Twenty-one percent of Ewing sarcoma samples had deletions of the STAG2 gene, and patients with STAG2 deletions had more aggressive tumors.

Soft-Tissue Sarcoma

–Among patients who also had surgery, intensity-modulated radiation therapy (IMRT) was associated with a lower local recurrence rate compared to conventional external-beam radiation.

–Six-month progression-free survival was 58% among 91 patients in a phase-II clinical trial of a hypoxia-activated cytotoxic agent (TH-302) used with doxorubicin.

–In a follow-up protocol comparison, radiography was noninferior to CT in terms of overall survival rate and disease-free survival.

–Ninety-five percent of 867 soft-tissue sarcoma patients who developed a recurrence did so within 8.6 years, raising questions about the usefulness of following patients beyond 10 years.

Reconstruction

–Due to high complication rates, intercalary allograft reconstruction after tumor resection should be reserved for defects of 15 cm or less, and plate-and-screw fixation should be used rather than intramedullary-nail fixation.

–Thirty-six patients who received frozen orthotopic autograft during reconstruction demonstrated a 10-year autograft survival rate of 80%.

–Patients who underwent pelvic reconstruction had a higher infection rate (26%), compared with those who did not undergo pelvic reconstruction (15%).

JBJS Classics: Correlating Lumbar MRIs with Clinical Findings

JBJS-Classics-logoEach 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.

In 1989, a group of sixty-seven asymptomatic individuals with no history of back pain or sciatica underwent magnetic resonance scans of the lumbar spine. In a landmark 1990 JBJS study, Boden et al. reported that three neuroradiologists who had no clinical knowledge of the patients interpreted the images as being substantially abnormal in 28% of the cohort (19 individuals). More specifically, a herniated nucleus pulposus was identified in 24 % of these asymptomatic subjects. These “magnetic-resonance positive” findings were more prevalent in older subjects; abnormal MRI findings were identified in 57% of those aged 60 to 80 years.

Boden et al. concluded that so many MRI findings of substantial abnormalities in asymptomatic people “emphasized the dangers of predicating a decision to operate on the basis of diagnostic tests—even when a state-of-the-art modality is used—without precise correlation with clinical signs and symptoms.”

However, despite the findings of Boden et al., during the last five years of the 1990s, Medicare claims showed a 40% increase in spine-surgery rates, a 70% increase in fusion-surgery rates, and a two-fold increase in use of spinal implants. Although spine-fusion surgery has a well-established role in treating certain spinal diseases, a 2007 systematic review of several randomized trials indicated that the benefits of fusion surgery were limited when treating degenerative lumbar discs with back pain alone. This review suggested the need for more thorough selection of surgical candidates, which was a caution also implied by Boden et al.

Although the three neuroradiologists in the Boden et al. study largely agreed on the absence or presence of abnormal findings on the MRIs, in 2014 Fu et al. reported on the interrater and intrarater agreements by four reviewers of MRI findings from the lumbar spine of 75 subjects. Even though this study used standardized evaluation criteria, there was significant variability in both interrater and intrarater agreement among the reviewers. As the Boden et al. study did 25 years ago, this study demonstrated the diagnostic limitations of MRI interpretation for lumbar spinal diseases.

In 2001, JBJS published a paper by Borenstein et al. that was a seven-year follow-up study among the same asymptomatic subjects studied by Boden et al. Borenstein et al. found that the original 1989 scans of the lumbar spine were not predictive of the future development or duration of low back pain. This led Borenstein et al. to conclude—as Boden et al. did—that “clinical correlation is essential to determine the importance of abnormalities on magnetic resonance images.”

Many important subsequent studies were inspired by the original findings of Boden et al. in JBJS. Most of them emphasize that for lumbar-spine diagnoses, an MRI is only one (albeit important) piece of data; that interpretation of MRIs is variable; and that all imaging information must be correlated to the specific patient’s clinical condition.

Several studies and national surveys indicate that approximately a quarter of US adults report having had back pain during the past 3 months, making this a common clinical complaint. But the findings of Boden, et al. and subsequent studies remind us that surgery is not always the appropriate treatment.

Daisuke Togawa, MD, PhD

JBJS Deputy Editor

Editor’s Choice – July 7, 2014

The June 18, 2014 article, “Normal Health-Related Quality of Life and Ability to Work Twenty-nine Years After in Situ Arthrodesis for High-Grade Isthmic Spondylolisthesis” by Joelson et al. reports results that challenge the current approach generally used in treating this pediatric spinal disorder.

Sweden and neighboring Scandanavian countries have been leaders in studying long-term results of treatment for a wide variety of orthopaedic conditions, with an impressive rate of follow-up in this relatively stable population. This article is one more example. Thirty-five of 40 patients were evaluated with physical examination and patient-reported outcome questionnaires at a mean of 29 years and a minimum of 23 years following L4-S1 posterior fusion and L5-S1 anterior fusion for isthmic spondylolisthesis over 50%. Harrington rod spinal instrumentation was used in 15% of the cases, while the others were treated with postoperative casts for 3 months. All patients were reported to have a solid fusion from the initial surgery, and there was no motor function loss. While there was a substantial range of scores in the outcome questionnaires, there was no significant difference in outcomes between the surgical patients and norms for the Swedish population.

Despite the results reported here, this approach to treating high-grade isthmic spondylolisthesis in the pediatric population has largely been replaced with pedicle screw and rod spinal instrumentation from L4 to S1, partial reduction of the slip, and posterior fusion, with anterior L5-S1 fusion added at times. The primary problem with this approach is that there is a reported risk of iatrogenic nerve root injury in 8% to 30% of cases, with resultant weakness or absent function of one or more distal extremity muscles, even if intraoperative neurologic monitoring is used.

The pendulum has essentially fully swung away from the treatment described in this article to the current instrumented approach.   The use of post-operative casts with in situ fusion is considered old-fashioned and a treatment thought not acceptable to patients today. However, given the good long-term results reported in this article with in situ fusion and casting, this approach needs to be re-introduced into the pre-operative discussion and be included as a very acceptable surgical option for young patients with high-grade isthmic spondylolisthesis. While we await the long-term follow-up results of patients treated with spinal instrumentation, partial reduction, and fusion as practiced today, avoiding the risk of neurologic deficit in the lower leg will lead some parents to select in situ fusion and casting, with casts generally being tolerated quite well by pediatric patients.