Tag Archive | spine

May 2017 Article Exchange with JOSPT

JOSPT_Article_Exchange_LogoIn 2015, JBJS launched an“article exchange” collaboration with the Journal of Orthopaedic & Sports Physical Therapy (JOSPT) to support multidisciplinary integration, continuity of care, and excellent patient outcomes in orthopaedics and sports medicine.

During the month of May 2017, JBJS and OrthoBuzz readers will have open access to the JOSPT article titled “Risk of Recurrence of Low Back Pain (LBP): A Systematic Review.”

In that systematic review, the authors found low quality and heterogeneity among studies of this topic. They concluded that “the available research does not provide robust estimates of the risk of LBP recurrence and provides little information about factors that predict recurrence in people recently recovered from an episode of LBP.”

JBJS Case Connections—Spinal Epidural Hematoma: Rare, But Potentially Devastating

CCX O'Buzz Image.gifSpinal epidural hematoma is a rare condition. Because the etiology is often unclear and the medical history is frequently innocuous, a high index of suspicion is required in order to maximize the chances of a successful outcome.

This month’s “Case Connections” spotlights 4 cases of spinal epidural hematoma involving 2 elderly women, a male Olympic-caliber swimmer, and a preadolescent boy.

In the springboard case, from the March 22, 2017, edition of JBJS Case Connector, Yamaguchi et al. report on a 90-year-old woman with a history of transient ischemic attacks (TIAs) and combined aspirin-dipyridamole therapy in whom a large spontaneous spinal epidural hematoma (SSEH) developed rapidly after she shifted her position in bed. The authors concluded that their case emphasized that “early diagnosis of an SSEH and prompt surgical intervention can avoid catastrophic and permanent neurological deterioration and compromise.”

Three additional JBJS Case Connector case reports summarized in the article focus on:

Among the take-home points from this “Case Connections” article: MRI is the gold standard for the diagnosis of spinal epidural hematomas, and treatment typically involves operative decompression consisting of laminectomies and evacuation of the hematoma.

JBJS Classics: Wiltse’s Paraspinal Muscle-Splitting Approach

JBJS Classics Logo.pngOrthoBuzz regularly brings 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 highlight the impact that these JBJS articles have had on the practice of orthopaedics. Please feel free to join the conversation by clicking on the “Leave a Comment” button in the box to the left.

Almost 50 years ago, in a classic 1968 JBJS paper, Leon Wiltse and co-authors described a novel and innovative access route to the lumbar spine. At that time, the vast majority of approaches to the lumbar spine were performed through midline incisions. Wiltse´s approach, however, utilized a more lateral access route to the spine. In this beautifully illustrated paper, the authors described a curved incision of the fascia and the skin with direct access to the transverse processes, pedicles, and the lateral masses.

The advantages of this novel access were multifold. Although wide midline laminectomies represented the gold-standard decompression technique at that time, the lateral approach served to avoid a more challenging and risky midline revision access, adding an elegant access for salvage procedures. Two goals of Wiltse’s approach were to achieve solid, posterolateral fusions and to decompress the neural structures. Graft harvest from the posterior iliac crest was easily facilitated with this approach.

Additional advantages included reduced blood loss and less muscle ischemia, and the preservation of spinous processes and intra-/supraspinous ligaments, which served to maintain the stability of the lumbar spine. The main downside was the necessity of performing two skin incisions as opposed to just one midline incision.

Since its introduction, Wiltse´s approach and the anatomic planes have been studied in great detail.1,2 Considering the vast developments in spine surgery over the last years and decades, the Wiltse approach has stood the test of time, as it still represents one of the main access routes to the lumbar spine that any skilled spine surgeon needs to master.

With the arrival of instrumentation, Wiltse´s approach was later employed in interbody fusion and minimally invasive transforaminal lumbar interbody fusion (TLIF) techniques, as it allowed direct access to the pedicles and the disc space. It has also been used for various techniques of direct pars repair.3

With the addition of some minor modifications, Wiltse´s approach still reflects the main access for minimally invasive, microsurgical treatment of foraminal and extraforaminal disc herniations, including bony decompression of the neuroforamen.4 The far lateral access permits sufficient decompression of the exiting nerve roots while preserving the facet joints, which serves to avoid more invasive fusion techniques for a considerable number of patients.

Overall, Wiltse´s innovative approach advanced spinal care by reducing access–related morbidity. Dr. Wiltse passed away at age 92 in 2005. His major achievements in spine surgery and his great accomplishments will remain in our memories and will continue to impact spine surgery over the coming decades.

Christoph J. Siepe, MD
JBJS Deputy Editor

References

  1. Vialle R, Court C, Khouri N, et al. Anatomical study of the paraspinal approach to the lumbar spine. Eur Spine J. 2005;14(4):366-71.
  2. Palmer DK, Allen JL, Williams PA, et al. Multilevel magnetic resonance imaging analysis of multifidus-longissimus cleavage planes in the lumbar spine and potential clinical applications to Wiltse’s paraspinal approach. Spine (Phila Pa 1976). 2011;36(16):1263-7.
  3. Xing R, Dou Q, Li X, et al. Posterior Dynamic Stabilization With Direct Pars Repair via Wiltse Approach for the Treatment of Lumbar Spondylolysis: The Application of a Novel Surgery. Spine (Phila Pa 1976). 2016;41(8):E494-502.
  4. Mehren C, Siepe CJ. Neuroforaminal decompression and intra-/extraforaminal discectomy via a paraspinal muscle-splitting approach. Eur Spine J. 2016.

Cardiopulmonary Effects of Scoliosis

ventilation-scatterplot_10_5_16The 3-dimensional spinal deformities associated with scoliosis may affect other organ systems. In the October 5, 2016 issue of The Journal, Shen et al. correlated radiographic severity of thoracic curvature/kyphosis with pulmonary function at rest and exercise capacity measured with a bicycle ergometer. Forty subjects with idiopathic scoliosis were enrolled in the prospective study (mean age 15.5 years), 33 of them female.

The study found no correlation between coronal thoracic curvature and static pulmonary function tests in the female patients. Female patients with a thoracic curve of ≥ 60° had lower blood oxygen saturation at maximal exertion during the exercise test, but overall exercise tolerance did not appear to be correlated with the magnitude of the thoracic curve and kyphosis. According to the authors, taken together, the many specific cardiopulmonary findings in this study suggest that “the cardiovascular system may be less affected than the respiratory system in patients with idiopathic scoliosis.”

Not surprisingly, exercise capacity was better in patients who performed regular aerobic exercise. Although physical training may not be able to change pulmonary pathology in this population, the authors emphasized that physical activity is still recommended for patients with idiopathic scoliosis for maintaining cardiovascular and peripheral muscle conditioning.

Long-Term Revision Rates after Cervical Spine Arthrodesis

cervical-arthrodesisMost studies looking into revision rates after cervical spine fusion follow patients for 2 to 5 years. But in the September 21, 2016 issue of JBJS, Derman et al. investigate revision rates—and risk factors for revision—with a follow-up of 16 years.

Analyzing New York State’s SPARCS all-payer database, the authors identified more than 87,000 patients who underwent a primary subaxial cervical arthrodesis from 1997 through 2012. During the study period, 7.7% of the patients underwent revision, with a median time to revision of 24.5 months.

Cervical arthrodeses performed with anterior-only approaches had a significantly higher probability of revision than those performed via posterior or circumferential approaches. The authors also found that the following characteristics were associated with an elevated revision risk:

  • Patient age of 18 to 34 years
  • White race
  • Workers’ Compensation or Medicare (but not Medicaid) coverage
  • Arthrodeses to address spinal stenosis, spondylosis, deformity, or neoplasm

Shorter arthrodeses (i.e., fewer fusion levels) and arthrodesis to address fractures were associated with relatively lower revision risks.

The authors conclude that “knowledge of these factors should help to promote exploration of strategies to reduce the prevalence of revision(s)…and to facilitate more accurate preoperative counseling of patients.”

Guest Post: Osteoporosis Treatment Still Lacking

OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Brett A. Freedman, MD, in response to a study published in JAMA about a new agent to prevent fractures in postmenopausal women with osteoporosis.

The August 16, 2016 issue of JAMA published the results of the ACTIVE (Abaloparatide Comparator Trial In Vertebral Endpoints) trial.  This 28-site randomized trial allocated postmenopausal women with low bone mineral density (BMD) and/or a prior fragility fracture into one of three arms:  abaloparatide (80 µg subcutaneously, daily ) vs. daily placebo injection vs. teriparatide (20 µg subcutaneously, daily).  The primary end point was new vertebral fracture over the 18-month trial.

As expected, both anabolic agents significantly outperformed placebo, with incident vertebral fractures occurring in only 4 subjects in the abaloparatide arm (0.6%) and 6 in the teriparatide arm (0.8%), while there were 30 in the placebo arm (4.2%).  Although the study was not powered to evaluate differences between the two anabolic agents, the results suggest that abaloparatide and teriparatide performed essentially the same over the 18-month period.

In an accompanying commentary,1 Cappola and Shoback note that institutional review boards (IRBs) approved a prospective clinical trial protocol in which patients with known osteoporosis and/or a prior fragility fracture were allowed to be randomized to a non-treatment arm for 18 months.  Subjects whose BMD dropped more than 7% from baseline and those who experienced an incident fracture during the trial “were offered an option to discontinue and receive alternative treatment,” but in some sense IRB approval of this protocol implicitly acknowledged that osteoporosis is undertreated.

Turning back to the study itself, I noted with interest that subjects who had regularly used bisphosphonates in the last 5 years or denosumab in the last year were excluded.  So, none of the 2463 subjects who were randomized had received any active treatment for osteoporosis in the 1 to 5 years prior to enrollment, despite the fact that the average T-score in the lumbar spine (-2.9 for all 3 arms) was in the osteoporotic range and that almost one-third of subjects had had at least one prior fragility fracture.

This is a sad commentary on “our” (meaning all providers involved in bone health) continued inability to diagnose and treat osteoporosis effectively.  Despite the “National Bone and Joint Health Decade” (2002-2011) and our continued attempts to “Own the Bone,” we have made little progress in recognizing and treating the osteoporosis underlying the fragility fractures that we so frequently treat.  Colleagues of mine and I published that only 38% of patients in 2002 with clinically diagnosed vertebral compression fragility fractures were receiving active treatment for osteoporosis.2  Over the ensuing decade, Solomon et al. showed that that figure actually decreased to 20%.3

This JAMA study provides empiric Level-I support for the efficacy of another anabolic agent to treat osteoporosis.  Cost, subcutaneous delivery, and osteosarcoma concerns have limited the only FDA-approved anabolic osteoporosis medication, teriparatide, to second-line status, behind bisphosphonates.  If and when approved, abaloparatide will probably bump up against the same limitations.  Still, the parathyroid hormone receptor agonists are particularly pertinent to orthopaedic surgeons, because they are the most effective secondary fracture prevention agents—and the only ones that show meaningful improvement in bone mineral density.  This bone-building property has also led to progressive acceptance of teriparatide as an important perioperative adjunct for instrumented spinal fusion surgery in patients with known osteoporosis.

However, as has been repeatedly shown, parathyroid receptor agonists only work when they are prescribed, and they are only prescribed when osteoporosis is diagnosed.2,3  Patients with incident clinical fragility fractures need to be effectively educated about osteoporosis, its treatment, and the impact of failing to treat it.  Orthopaedic surgeons need to continue to set the signal flares and advocate for our patients to receive effective treatment for all their chronic musculoskeletal illnesses, not the least of which is osteoporosis.

References:

  1. Cappola AR, Shoback DM. Osteoporosis Therapy in Postmenopausal Women With High Risk of Fracture. JAMA. 2016 Aug 16;316(7):715-6.
  1. Freedman BA, Potter BK, Nesti LJ, Giuliani JR, Hampton C, Kuklo TR. Osteoporosis and vertebral compression fractures-continued missed opportunities.Spine J. 2008 Sep-Oct;8(5):756-62.
  1. Solomon DH, Johnston SS, Boytsov NN, McMorrow D, Lane JM, Krohn KD. Osteoporosis medication use after hip fracture in U.S. patients between 2002 and 2011. J Bone Miner Res. 2014 Sep;29(9):1929-37.

No BMP–Cancer Link Found in Older Patients After Lumbar Arthrodesis

The July 6, 2016, edition of The Journal of Bone & Joint Surgery features a large case-cohort study that may help older patients and clinicians decide whether to use bone morphogenetic protein (BMP) as an adjunct to lumbar arthrodesis. Among Medicare patients aged 65 years and older, Beachler et al. found that BMP use was not associated with the following:

  • Overall cancer risk
  • Increased risk of individual cancer types
  • Increased risk of cancer in people who had cancer prior to undergoing lumbar arthrodesis
  • Increased mortality after a cancer diagnosis

BMP was used in 30.7% of >3,600 lumbar-arthrodesis patients analyzed, and the lack of association between BMP use and cancer held whether patients received the growth factor as part of an FDA-approved anterior lumbar interbody fusion or as an off-label application.
BMP-Cancer.gif
In an accompanying commentary, Singh et al. laud the authors for designing a study that was not only well-powered but also analyzed risk among those with a medical history of cancer. The commentators emphasize, however, that the median follow-up in this study was 2.4 years, leading them to wonder “whether this time frame is sufficient to evaluate the impact of BMPs on carcinogenesis.”

Until a large, prospective, randomized trial on this subject is conducted, Singh et al. say, “the decision to use BMPs should be made on the basis of sound clinical judgment by the treating physician after a full disclosure of the potential risks to the patient.”

New JBJS CME Subspecialty Exams

OEC LogoNew subspecialty CME exams are now available from The Journal of Bone & Joint Surgery in the following topic areas:

  • Adult Hip Reconstruction
  • Adult Knee Reconstruction
  • Shoulder and Elbow
  • Spine
  • Sports Medicine
  • Trauma

Each exam consists of 10 questions based on articles published in JBJS within the past 12 months. Exams can be used for study purposes at no cost. Each exam activity may be submitted for a maximum of 5 AMA PRA Category 1 Credits™.

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.