The Scientific Program Committee received more than 1,000 abstract and session proposal submissions for this year’s Annual Meeting in Boston. From this year’s selected submissions, the 21 highest rated abstracts will be presented during three separate Best Paper sessions on Wednesday, Thursday and Friday at NASS 2016.
Following are previews of 11 of this year’s Best Papers (presenting author listed in bold). Read previews of the other 10 Best Paper presentations in the July e-preview edition of the NASS Daily News.
Wednesday, October 26, 2016
BEST PAPERS: CERVICAL MYELOPATHY
Does Sagittal Balance Influence the Surgical Outcomes of Patients with Cervical Myelopathy?
Paul W. Millhouse, MD, MBA; Kristen Nicholson , PhD; Emily Pflug, BS; Barrett Woods, MD; Gregory D. Schroeder, MD; Christie E. Stawicki; D. Greg Anderson, MD; Alan S. Hilibrand, MD; Christopher K. Kepler, MD, MBA; Mark F. Kurd, MD; Jeffrey A. Rihn, MD; Alexander R. Vaccaro, MD, PhD; Kris E. Radcliff, MD
Cervical spondylotic myelopathy (CSM) is a progressive disease that can result in neurological decline. Cervical sagittal balance is an important outcomes parameter for surgical reconstruction. In this study, the researchers sought to determine how baseline sagittal balance (as measured by various cervical radiographic parameters) influences improvements in a patient’s health (overall physical and mental status, disability, pain and myelopathy symptoms) following surgery for CSM.
“We found no correlations between any preoperative radiographic parameters and absolute postoperative neck or arm pain scores,” said. Paul W. Millhouse, MD, MBA, of the Rothman Institute in Philadelphia. “There were no significant correlations between any baseline radiographic parameter and NDI or SF-12.”
Additionally, Dr. Millhouse said, no significant differences were found in baseline radiographic parameters between patients who achieved clinically significant (>MCID) changes in NDI scores and those who did not.
“Baseline sagittal plane alignment does not appear to be well correlated with postoperative health-related outcomes in patients with cervical myelopathy,” he said. “Cervical sagittal balance seems to influence pain and severity of myelopathy on presentation only. Surgical treatment improved pain and myelopathy, as measured by mJOA, regardless of radiographic parameters.”
The Effect of Smoking on Spinal Cord Healing following Surgical Treatment for Cervical Myelopathy
David Kusin, MD; Nicholas U. Ahn, MD
The harmful effects of smoking on healing have been well established; however, there is scant data regarding the effect of smoking on postoperative outcomes for cervical myelopathy. In this study, researchers attempted to quantify the effect using the Nurick scale. The Nurick scale grades the severity of cervical myelopathy from 0 to 5, with 5 being the most severe.
“We found that tobacco use was directly correlated with decreased postoperative improvement in Nurick score,” said David Kusin, MD, of the University of Nebraska Medical Center in Omaha. “Specifically, the mean improvement in Nurick score was almost one point lower in smokers than in nonsmokers.”
The researchers also found that the association was dose dependent. Dr. Kusin said that greater tobacco use was associated with a greater decrease in clinical improvement. Smoking history was not associated with a more severe preoperative condition, he said, which suggests that smoking may interfere with the intrinsic healing processes that occur in the spinal cord postoperatively, but may not be an important etiology of cervical myelopathy.
“These data suggest that patients with cervical myelopathy who smoke are likely to have less improvement in their condition postoperatively compared to those who do not smoke, and that the effect of each cigarette is additive,” Dr. Kusin said. “Interestingly, our work suggests that smoking does not contribute to the severity or development of cervical myelopathy, but it may harm the healing response postoperatively. These findings reinforce the importance of counseling patients about smoking cessation prior to surgery.”
Tobacco Smoking and Outcomes of Decompressive Surgery in Patients with Symptomatic Degenerative Cervical Myelopathy
Paul M. Arnold, MD; Branko Kopjar, MD, PhD; Lindsay A. Tetreault, PhD; Hiroaki Nakashima, MD; Michael G. Fehlings, MD, PhD, FRCSC
Tobacco smoking has been associated with wound infections, poor healing capacity, worse surgical outcomes, and higher rates of non-union following spine surgery. It is unclear, however, whether smoking is a predictor of functional status, quality of life, and complications in patients undergoing surgical decompression for the treatment of degenerative cervical myelopathy (DCM). The objective of this study was to examine the association between tobacco smoking and outcomes following surgery for the treatment of DCM.
“Tobacco smoking is strongly associated with suboptimal clinical, functional and quality of life outcomes. While both nonsmokers and smokers benefit from surgical decompression, the extent of improvement was significantly higher in nonsmokers than in smokers,” said Paul M. Arnold, MD, of the University of Kansas Medical Center. “Quantitatively, smokers experience 15% to 30% less improvement than nonsmokers and have a significantly lower degree of recovery.”
Among the potential explanations for suboptimal outcomes in smokers, smoking may cause a decrease in local blood flow and amplify the hypoxic conditions caused by cord compression. In addition, smoking may worsen the severity of schema repercussion injury following surgical decompression, likely through endothelial dysfunction and increased levels of free radicals.
It is unclear whether patient outcomes would improve if smoking were ceased prior to surgery or whether cigarette smoking creates chronic damage that will not reverse following cessation. Furthermore, it is unclear whether there is a minimum duration between surgery and smoking cessation that would optimize outcomes.
“Clinicians should be informed that smoking leads to substantial pathophysiological changes and that these changes may significantly impair functional recovery following surgical intervention,” Dr. Arnold said. “Patients who are smokers are advised to quit smoking before surgery, even though it is still unclear whether smoking cessation improves outcomes. At the very least, their expectations of outcome should be managed accordingly.”
Thursday, October 27, 2016
BEST PAPERS: BIOLOGICS AND INTERVENTIONAL CARE
Further Research on the Efficacy of a New Navigable Percutaneous Disc Decompression Device (L’DISQ) in Patients with Lumbar Radicular Pain: Two-Year Follow-Up
Sung Hoon Kim; Sang-Heon Lee, MD, PhD; Nack Hwan Kim; Richard Derby MD, PhD
While the efficacy and safety of disc ablation with radiofrequency energy has been previously demonstrated, nucleoplasty using radiofrequency ablation is restricted by the difficulty associated with focal direct removal of the herniation. To overcome this liability, the investigators in this study developed a navigable decompression device, “L’DISQ,” designed to allow direct access to the herniated disc material. In this paper, they report the clinical outcomes of focal-direct ablation to herniated disc materials using the L’DSIQ device after long-term follow-up.
“Most previously developed percutaneous decompression devices, which use plasma energy, are designed to decompress the center of the nucleus rather than the herniated disc directly,” said Sang-Heon Lee, MD, PhD, of the Korea University School of Medicine in Seoul, South Korea. “Therefore, a comparatively large amount of tissue reduction in the central disc would be required, and excessive disc tissue removal would accelerate the disc degeneration and reduce the disc height.”
In contrast to most percutaneous nucleotomy devices that use a rigid and uncontrolled tip, Dr. Lee said the wand tip of the L’DSIQ device can be curved by rotating the control wheel and directed into the disc herniation.
“Our study demonstrated that decompression with L’DISQ device is relatively safe and effective in relieving pain and decreasing disability of patients with lumbar radicular pain,” Dr. Lee said. “We believe L’DISQ will be another good treatment option in lumbar herniated intervertebral disc.”
Trans-Sacral Epiduroscopic Laser Decompression (SELD) for the Treatment of Symptomatic Lumbar Disc Herniations (LDH): Single Center Experience of Clinical and Radiologic Results in Minimum 12-Month Follow-Up
Jung-Woo Hur, MD; Jin-Sung Kim, MD, PhD; Ji-hoon Seong, MD
Percutaneous trans-sacral procedures are frequently performed as a treatment option for lumbar disc herniation (LDH), but they are limited in that they cannot completely remove the causing pathology. With recent developments in laser and endoscopic technology, trans-sacral epiduroscopic laser decompression (SELD) has received attention as an alternative tool. The purpose of this study is to evaluate efficacy and safety of SELD by reporting preliminary clinical and radiologic results of SELD for the treatment of LDH in a single-center experience. Clinical outcomes were evaluated using visual analog scale (VAS) scores for back and leg pain, and functional status was measured with Oswestry disability index (ODI).
“More than 71% of patients showed immediate symptom relief postoperatively and over 85% of patients showed relief at final follow-up,” said Jung-Woo Hur, MD, of Seoul St. Mary’s Hospital, the Catholic University of Korea, in Seoul, South Korea. “The average VAS scores for back and leg pain, as well as ODI, showed statistically significant improvement at final follow-up.”
Immediate postoperative MRI showed subtle changes in most of the patients, Dr. Hur noted; however, final follow-up images revealed significant reduction of disc pathology in more than 80% of patients.
“Reduction in disc size may be owing to the natural course of disc herniation pathophysiology, but correlation with clinical improvement signifies the safety of procedure in 12-month follow-up,” Dr. Hur said. “The results of this preliminary study suggest that SELD is an effective and safe therapeutic modality for patients with symptomatic LDH.”
Greater Expectations of Pain Improvement are Associated with Less Actual Pain Improvement after Lumbar Surgery
Carol A. Mancuso, MD; Manney Reid, MD, PhD; Roland Duculan, MD; Alex Fong, BA; Manuela C. Rigaud , MA; Frank P. Cammisa, MD; Andrew A. Sama, MD; Alexander P. Hughes, MD; Darren R. Lebl, MD; Federico P. Girardi, MD
Various outcomes have been studied after lumbar surgery; however, long-term improvement in pain remains the main goal for most patients. In a prospective cohort of 422 lumbar surgery patients, the goal of this study was to measure the amount of pain improvement received two years after surgery and compare it to the amount of pain improvement expected before surgery.
“We previously developed a survey to measure patients’ preoperative expectations of lumbar surgery,” said Federico P. Girardi, MD, of the Hospital for Special Surgery in New York. “One item in the survey asks about expected improvement in pain. A postoperative version of the survey asks patients to rate the amount of improvement received from a global perspective.”
Two years after surgery, 11% of patients reported no improvement in pain, 28% reported little to moderate improvement, 44% reported a lot of improvement and 17% reported complete improvement. Overall, 56% of patients received less improvement in pain than expected; most of these patients had expected complete improvement.
“Expecting greater pain improvement preop is associated with patients’ rating of less pain improvement postop. Expecting complete pain improvement, in most cases, is unrealistic,” Dr. Girardi said. “Given that expectations are potentially modifiable, this study supports addressing pain-related expectations with patients before surgery through discussions with surgeons and through formal patient education.”
Correlating Patient-Reported Outcomes to Patient Satisfaction in Patients’ with a Lumbar Disc Herniation
Gregory D. Schroeder, MD; Alan S. Hilibrand, MD; Alexander R. Vaccaro, MD, PhD; Wenyan Zhao, PhD; Jon D. Lurie, MD; Kris E. Radcliff, MD
In this study, investigators performed a retrospective subgroup analysis of prospectively collected data from the Spine Patient Outcomes Research Trial (SPORT) to determine if patient satisfaction is predicted by improvement in health related quality of life (HRQOL) metrics in patients with a lumbar disc herniation.
Patients enrolled in the SPORT study were prospectively enrolled at 13 institutions; 709 patients who underwent surgery and 319 patients treated without surgery were included. For this study, patients were considered satisfied if they were either “very satisfied” or “somewhat satisfied,” and they were not satisfied if they were “somewhat dissatisfied” or “very dissatisfied.” HQOL metrics included: SF-36 and Oswestry Disability Index (ODI).
In the surgical cohort, ROC analysis demonstrated that SF-36 PCS improvement had moderate accuracy at predicting satisfaction at three months, and excellent accuracy at predicting satisfaction at two years and four years. Absolute PCS score had excellent accuracy at three months, two years and four years. Similarly, improvement in the ODI had a moderate accuracy of predicting satisfaction at three months, two years and four years, and the absolute ODI score had excellent accuracy at three months, two years and four years.
Separate logistic regression models were required to determine the individual impact of SF-36 PCS improvement, SF-36PCS score, ODI improvement and ODI score on patient satisfaction. SF-36PCS improvement, ODI improvement and ODI score were found to be independent predictors of patient satisfaction at all time points, but the SF-36 PCS score was only a significant predictor at three months and two years.
Based on their findings, the researchers conclude that patient satisfaction is an accurate proxy for HRQOL metrics three months, two years and four years after a lumbar disc herniation.
Friday, October 28, 2016
BEST PAPERS: DISC REPLACEMENT AND SOCIOECONOMICS
Surgical versus Nonsurgical Treatment for Cervical Radiculopathy: A Cost-Effectiveness Analysis
Jeffrey A. Rihn, MD; Suneel Bhat, MD; James S. Harrop, MD; Zoher Ghogawala, MD, FACS; Jonathan N. Grauer, MD; Alan S. Hilibrand, MD
The majority of cases of acute cervical radiculopathy respond well to conservative management within six weeks. In cases that persist, the literature remains unclear on whether continued nonsurgical management with epidural injections or anterior cervical discectomy and fusion (ACDF) is more clinically and economically effective. In this study, researchers attempted to compare the cost-effectiveness and outcomes of the two approaches to treating cervical radiculopathy that persists beyond six weeks.
“We found that ACDF in patients who have failed six weeks of noninvasive conservative management is the dominant cost-effective strategy when compared to epidural injections and continued physical therapy,” said Jeffrey A. Rihn, MD, of the Rothman Institute in Philadelphia. “The study is a decision model analysis with limitations. The literature, particularly on outcome following injections and/or physical therapy, is somewhat limited.”
This finding, Dr. Rihn noted, suggests that policies requiring a trial of epidural injections prior to operative management may, in fact, delay improvement in cases of MRI-confirmed disc disease with radicular symptoms and result in greater direct and indirect costs.
“This study represents the first cost-effectiveness model of management of cervical radiculopathy, and can help manage clinical decision-making and policy to optimize efficient outcomes for patients suffering from the condition,” Dr. Rihn said.
Missing Data May Invalidate Spine Surgery Database Studies
Bryce Basques, MD, MHS; Adam M. Lukasiewicz, MSc; Andre Samuel, BA; Matthew Webb; Daniel D. Bohl, MD, MPH; Junyoung Ahn; Kern Singh, MD; Jonathan N. Grauer, MD
National databases are increasingly used for research in spine surgery; however, the prevalence of missing data is one limitation that has received sparse mention in the literature. The purpose of this study aimed to shed light on the extent of missing data in national database studies and to illustrate how different treatments of missing data can significantly skew the results of spine surgery database studies.
“Studies using these databases often do not emphasize the percentage of missing data for each variable used, and do not make note of how patients with missing data are incorporated into analyses,” said Bryce Basques, MD, MHS, of the Rush University Medical Center Department of Orthopedic Surgery in Chicago, IL.
Looking at the American College of Surgeons National Quality Improvement Program (ACS-NSQIP) database, Dr. Basques said that missing data was common for spine surgery patients, with 20 comorbidity variables having 65.54% missing data, as they are now only collected at certain ACS-NSQIP participating sites.
“There are multiple studies in the literature that have used this cohort of spine patients, and the majority of these studies fail to comment on the amount of missing data or how it was treated in analyses,” he said. “This investigation raises significant questions about the validity of these studies. It is important for researchers to be aware of the significant limitations to database research, particularly missing data, when designing, performing and evaluating these studies.”
Neurologic Outcome following Intraoperative Neurophysiological Signal Change in Cervical, Thoracic, Lumbar and Multiregional Spine Surgery
Anthony K. Sestokas, PhD; Eric A. Tesdahl, PhD; Andrew F. Cannestra, MD, PhD; Sarah E. Baran, PhD, CNIM; Jeffrey Cohen, MD, PhD; Samuel Weinstein, MD, MBA
Intraoperative neurophysiological monitoring (IONM) provides real-time feedback on evolving injury during spine surgery, affording opportunity for the surgeon to intervene and potentially avoid or mitigate postoperative neurologic deficit. Little is known about the relationship between intraoperative reversal of identified neurophysiologic change during surgery and neurologic outcome following surgery in different regions of the spine. The purpose of this study is to quantify the relationship between intraoperative reversal of identified neurophysiologic change during surgery and neurologic outcome following cervical, thoracic, lumbar and multiregional spine surgery.
“Our research looks at the incidence and reversibility of adverse neurophysiologic changes during extradural spine surgery in adult patients,” said Anthony K. Sestokas, PhD, of SpecialtyCare in Nashville, TN. “Specifically, the research compares postoperative neurologic outcomes immediately following spine surgery in which adverse intraoperative neurophysiologic changes were identified as fully resolved, partially resolved or unresolved by the end of the procedure.”
Their findings suggest that the degree of resolution of adverse neurophysiologic change during extradural spine surgery is quantitatively predictive of postoperative neurologic outcome, Dr. Sestokas said, noting that there is an elevated degree of predicted neurologic risk for surgical procedures that address the thoracic spine.
“The majority of neurophysiologic changes detected by neuromonitoring in the present series of procedures were reversed successfully and were associated with positive outcomes,” he said. “Intraoperative neuromonitoring with proper vigilance and prompt intervention during spine surgery will support reducing postoperative neurologic injury.”
The Total Cost to the Health Care System for the Treatment of Cervical Myelopathy
Gregory D. Schroeder, MD; Christopher K. Kepler, MD, MBA; Mark F. Kurd, MD; Alan S. Hilibrand, MD; D. Greg Anderson, MD; Kris E. Radcliff, MD; Barrett Woods, MD; Tyler Kreitz, MD; David Casper, MD; Jason W. Savage, MD; Jeffrey A. Rihn, MD; Alexander R. Vaccaro, MD, PhD
Cervical myelopathy is a common reason patients over 65 years of age undergo cervical spine surgery and, in recent years, there has been increased awareness of the need to deliver not only high quality, but also cost-effective treatment. This study sought to compare the total health care costs for patients treated with and without surgery for cervical myelopathy.
The Center for Medicare and Medicaid Services Carrier File for the years 2005–2012 was reviewed using the PearlDiver Technologies database to identify all patients with a new diagnosis of myelopathy by ICD-9 code. All patients were required to have had 12 months without the diagnosis prior to index diagnosis, and the diagnosis must have been reported twice within the 12 months after initial diagnosis.
Among their findings, the researchers report that surgical treatment resulted in a significant increase in total health care costs of for patients diagnosed with myelopathy in 2009 and 2011; however, as the length of follow-up increased, the total health care costs converged, such that there was a nonsignificant increase in health care costs for patients treated with surgery in 2007 and a nonsignificant decrease in total health care costs for patients treated with surgery who were diagnosed with myelopathy in 2008.
While the researchers acknowledge the probability of some selection bias in the study, they believe their findings highlight the fact that, when evaluating the cost-effectiveness of surgery for myelopathy, it is critical to look beyond the cost of the surgery itself, as failing to address this progressive disease may lead to a substantial increase in total health care expenditures.