NASS 2020 Highest-Rated Abstracts
The NASS 2020 Scientific Program Committee received a total of 1,234 abstracts.The 23 highest-rated abstracts earned the coveted 'Best Paper' designation and will be presented throughout the virtual meeting.
Wednesday's Best Papers
Use of ALIF at the lumbosacral junction results in less lumbopelvic fixation failure than TLIF or no interbody fusion following correction of adult spinal deformity–Presenting Author: Robert Eastlack, MD
  1. What question is your research attempting to answer?
    Given the known variations in biomechanical stresses appreciated by lumbopelvic fixation, as well as the differential failure mechanisms evident within this region following spinal reconstructions to the pelvis, we aimed to determine if utilizing different types of interbody devices would lead to unique patterns of failure within the lumbopelvic portion of the construct.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    ALIF at L5-S1 (the lumbosacral junction) resulted in a decreased likelihood of rod fracture and pseudarthrosis when compared to TLIF or no interbody utilization. This differential occurred despite a considerably lower use of bilateral pelvic fixation in the patients that had ALIF at the lumbosacral junction. These results imply that there is greater strain on the rods when using less structurally supportive interbody devices at L5-S1 for adult deformity surgery that crossed the lumbosacral junction, and this leads to higher fixation failure rates, as well as more motion that may disrupt the fusion consolidation in this area.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    The loosening of pelvic fixation did not differ between groups, which suggests that the presumed increased motion and higher rod strain within the groups that did not have interbody devices or had TLIFs at L5-S1, did not appreciably result in a change in strain on the pelvic bolts/fixation, when compared to those patients with ALIF interbody support at L5-S1. The similarity between these groups may affirm that escalation of stress at the sacroiliac joints may occur sufficiently to result in greater motion and therefore fixation loosening as a result of the longer lever arm and stiffness of deformity surgery regardless of the interbody support at L5-S1.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    Patients undergoing adult deformity surgery should be considered for supplemental posterior fixation when performing TLIF or when not using interbody support at L5-S1. Additionally, unilateral or less substantial pelvic fixation may be feasible when utilizing ALIF at L5-S1 when performing reconstruction for adult spinal deformity. Applying information from this study and prior biomechanical analyses can lead to significantly less failure and complications related to performing adult spinal deformity, and thus reduce the risk and cost implications of revision surgery.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    Prospective randomized trials that further identify failures as they relate to differential biologics use, as well as supplemental posterior fixation (eg, four rods, double bilateral pelvic fixation, etc), will further our knowledge and improve our care of patients undergoing adult spinal deformity reconstruction to the sacrum/pelvis.

The re-herniation after decompression (RAD) score identifies patients at low-risk for re-herniation after lumbar decompression surgery–Presenting Author: Garrett K. Harada, MD
  1. What question is your research attempting to answer?
    Lumbar intervertebral disc herniations are a common cause of low back and radiating pain that may require surgical intervention. Estimates suggest that up to 23% of patients will experience a recurrent disc herniation while 6% will require additional surgery following surgical decompression. As such, the purpose of our study was to attempt to create a preoperative risk-stratification scoring tool that may help accurately identify which patients may be at high- or low- risk for recurrent herniation events.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    From 2006 to 2018, 9.9% (51/517) of patients presenting for microdiscectomy of a lumbar herniated nucleus pulposus (HNP) experienced a reherniation event. The strongest predictors for reherniation were identified using a LASSO model (age, sex, American Society of Anesthesiologists (ASA) class, operative levels, duration of preoperative symptoms, paracentral disc herniations, pelvic incidence, lumbar lordosis, and Visual analog scale (VAS) Leg scores), whereby two high- and low- risk cohorts were readily identified. High-risk patients experienced reherniations at a rate of nearly 30% while nearly all low-risk candidates experienced no further HNPs.

    Given the relatively high rate of recurrent HNPs following decompression, this model provides a much-needed tool for practitioners to identify who is likely to respond well to current surgical therapies while also highlighting a group that may benefit from further innovations in technique or longer periods of non-operative management. Furthermore, this tool can provide a profile for preventative measures as well as have direct clinical application to predict outcomes and help better consult the patients, manages expectations and further personalize management.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    Over the past few decades, most efforts have been focused on improving and/or modifying existing surgical decompression techniques to address this issue. Unfortunately, most innovations have failed to significantly reduce symptomatic reherniation rates and have been accompanied by a fair share of other complications. Part of this issue may be due to a prevailing 'one-size-fits-all' approach, whereby many believe one specific technique or modification can be made to adequately treat all HNP patients. Our findings demonstrate that there is measurable heterogeneity in surgical HNPs, and a traditional microdiscectomy may largely be appropriate in low-risk patients. Rather, high-risk patients likely constitute the cohort that should be the target for further innovations in management and techniques. This work further feeds into the concept of precision-based spine care, whereby this model can further contribute to a larger, big data approach in identifying patients at risk, developing the right treatment for the right patient at the right time.

    Our proposed scoring scheme further provides a quantitative measure to help identify high- and low-risk patients for disc reherniation following a discectomy. This work bypasses the typical intuition that some clinicians utilize to predict outcomes and puts behind it some sound evidence based on an exhaustive analytical approach and modeling.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    Spine patients will benefit from implementation of the RAD score in a number of ways. As most HNPs are primarily managed with varying periods of physical therapy and anti-inflammatory medications, there remains a timepoint where the clinician must decide whether or not such non-operative therapies remain effective. For many, this threshold may vary considerably, with some patients enduring months or years of pain ultimately attributable to a surgical HNP. The RAD score may be used at this juncture to assist with clinical-decision making, where low-risk patients may proceed confidently to surgery and high-risk patients may benefit from longer trials of non-operative therapy due to greater reherniation rates. Further, as mentioned previously, high-risk patients may also be targets for new therapies or innovations and could help expedite the development of more effective surgical approaches or techniques. Collectively this suggests the RAD score may help make the clinical management of HNP patients more efficient and less costly, all while provoking further research and development.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    As with any new model or risk-stratification tool, the RAD score must be vetted and tested across different institutions, patient cohorts and ethnic groups to determine its ultimate utility.

    To do so, practitioners should investigate whether or not the RAD score is capable of predicting high- and low-risk reherniation patients accurately at their respective practices. Once validated, the RAD score can then be used to support clinical-decision making and as a tool to supplement further spine research. Irrespective, this tool should not be used as a stand-alone method to provide or deny indicated treatment, as each patient is always accompanied by a number of lifestyle, socioeconomic and other extenuating circumstances that also likely contribute to outcomes after a given procedure.

Global spine outreach (GSO): how to safely establish a sustainable short-term spine deformity outreach program–Presenting Author: Fernando Rios, MD
No information available.
At what point should the thoracolumbar region be addressed in patients undergoing corrective cervical deformity surgery?–Presenting Author: Peter Passias, MD
  1. What question is your research attempting to answer?
    Will certain ratios of cervical to thoracolumbar radiographic parameters impact occurrence of poor outcomes in following cervical deformity corrective surgery?

    Cervical deformity surgery is often unsuccessful due to distal failure or maladaptive reciprocal changes, and the surgeon has to determine where to end the fusion and when to include the thoracic spine. This study sought to determine the relationship between the cervical spine and the thoracolumbar spine. We wanted to establish if the thoracic spine should be included in the construct and whether this will have a better result clinically and decrease poor outcomes.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    In this study, we found key ratios of cervical to global alignment that correlate with the sub-optimal clinical outcomes of major complications, reoperation, distal junctional kyphosis and not meeting the clinically important difference in HRQL outcomes. We determined that having a larger cervical parameter over its thoracolumbar counterpart significantly predicts a poor postoperative outcome. Clinically, physicians should consider cervical to global alignment, as it critically determines outcomes in cervical deformity corrective surgery.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    Historically, we looked at the cervical and thoracic spine separately. What we are seeing is that the severe disease of cervical deformity requires the two regions of the spine to be assessed together, as the regions of the spine coexist. When the cervical spine is affected, reciprocal changes often occur in the thoracolumbar spine.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    We hope to guide surgeons to properly treat cervical deformity patients and minimize high risk of surgery and the distal issues that occur in up to 30% of patients.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    The next step is to apply some of the ratios prospectively to see if adaptation and appliance in real-time would improve outcomes and reduce reoperation.

Are octogenarians at higher risk for complications after elective lumbar spinal fusion surgery compared with younger patients? A study from the Kaiser Permanente National Spine Registry–Presenting Author: T. Kent Ganocy, II, MD
  1. What question is your research attempting to answer?
    Given the growing number of spinal surgeries being performed on patients aged 80 and older, our goal was to use our Registry Data to understand risks of elective thoracolumbar spinal fusion surgery in this group of patients compared to a younger cohort aged 50-79.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    Patients aged 80 and above undergoing spinal fusion had a significantly higher risk of intraoperative durotomy, pulmonary embolism at 90 days, and 90-day hospital readmission. Expectedly, mortality was also higher in these patients, although this risk was not increased 90 days after surgery compared to two years..

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    Although the risk of mortality was higher in patients aged 80 and older, the risk did not significantly differ 90 days after surgery compared to two years, which suggests that the increased risk is from differences in age rather than spinal fusion surgery. There were no deaths in patients 80 and older with less than three comorbidities at 90 days postoperatively. After two years of followup, risk of death in patients aged 80 and above with three or more comorbidities was 4.7 times higher compared to the same age group with two or less suggesting that overall health may be a better predictor of postoperative mortality than age.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    The average age of our patients is increasing as life expectancy steadily increases due to improved health and medical advances. Incidence of degenerative spinal disorders also increases with age, and patients in their 80s and beyond can potentially benefit from spinal surgery to remain active and mobile. As a result, it has become more important than ever for physicians to be able to realistically discuss the safety of undergoing spine surgery with our older patients so that we can help them make better informed decisions regarding their treatment options.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    Additional research with a larger number of patients 80 and older will allow more in-depth comorbidity research, longer follow-up assessment, as well as detailed consideration of risks of undergoing specific types of spinal fusion, as well as non-fusion surgery which we were not able to assess in this study.

PLF or ALIF+PS: which has a lower operative nonunion rate? Analysis of a cohort of 2,061 patients from a national spine registry–Presenting Author: Betty Norheim, MD
  1. What question is your research attempting to answer?
    Which has lower reoperation rates for nonunions (operative nonunions): posterolateral fusions with pedicles screws (PLF) or anterior lumbar interbody fusion with pedicles screws (ALIF+PS)?

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    In a large cohort of 2,061 patients with > 4 years followup, with the diagnosis of degenerative disc disease or spondylolisthesis between L4-S1, we found no difference in operative nonunion rates between PLF and ALIF+PS.

    The significance is that when clinical information and radiographic findings for nonunions are combined using operative nonunion as an outcome measure the reoperations rates were similar for PLF and ALIF +PS when the fusion is from L4 to S1.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    The results of our study may be controversial, since for one of the few times in spine surgery our results showed that less spinal instrumentation (PLF) has comparable results to more instrumentation (ALIF+PS). It also shows that what matters to patients and payors is not what is radiographic nonunions of a particular procedure, but what is the probability of returning for another spine surgery. Finally, we must constantly retrospectively look at our surgical results and see if there are ways to improve our surgical practices and not rely on concept “one size fits all.”

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    In patients who require a lumbar spinal fusion between L4 to S1, surgeons are able to make the choice based on their own discretion as to which surgical approach is best between PLF and ALIF+PS. Surgeons performing posterior lumbar fusion cases should not feel obligated to add the anterior support, which often times leads to increased cost.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    This research was specifically done in patients with degenerative disease and spondylolisthesis with fusions L4-S1. We need to further investigate if similar results are obtained when the fusion length is extended from L1 to S1 or T12 to pelvis. Spine specialists should not necessarily use ALIFs to increase fusion rates between L4-S1 unless it is used to correct deformity.

Mild and severe obesity reduce effectiveness of lumbar fusions: one-year patient-reported outcomes in 8,171 patients–Presenting Author: Olivia Rice, MD
  1. What question is your research attempting to answer?
    Is the overall effectiveness of lumbar fusion surgery compromised by obesity, in the absence of surgical complications?

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    A total of 8,171 patients met inclusion criteria: 2,435 with Class I obesity (BMI 30-35 kg/m2), 1,328 with Class II (35-40 kg/m2), and 760 with Class III (≥40 kg/m2). Increasing BMI was independently associated with worse 12-month Oswestry Disability Index (ODI) (t=8.005, p<0.001) and decreased likelihood of achieving minimal clinical important difference (MCID) (OR=0.977, p<0.001). One year after surgery, mean ODI, ODI change, and percentage achieving MCID worsened with Class I, Class II and Class III vs non-obese cohorts (p<0.001) in stepwise fashion.

    These findings suggest there is a significantly lower likelihood for meaningful clinical improvement after lumbar fusion for patients with BMI > 30 vs < 30 kg/m2.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    An elective surgery is ‘effective’ when its outcome matches the surgeon’s and patient’s expectations. This typically includes improvement in pain-related disability and avoidance of complications. Existing literature shows a positive correlation between increasing BMI and risk of perioperative complications. This study illustrates that independent of surgical complications, elevated BMI reduces the likelihood of reaching the MCID between preoperative and postoperative ODI patient reported outcome scores. This tells us that the effectiveness of elective lumbar fusion is compromised in obese patients.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    These findings allow spine surgeons to better inform patients with elevated BMI on the risks and maximal benefit possible for elective lumbar fusion. By helping patients understand the implications of these results, we may indirectly increase their likelihood for clinical improvement through motivation and successful weight loss prior to surgery.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    We will continue to follow these patients until they reach the 2-year postoperative time point, and report our findings at that time. Like past studies, this analysis shows that the majority of obese patients, even those with BMI ≥ 40 kg/m2), still benefit from surgical intervention (> 50% of patients met ODI MCID). Therefore, we do not recommend global refusal of lumbar fusion surgery due to elevated BMI. These results should encourage greater allocation of resources to preoperative optimization, and aid discussions surrounding surgeon and patient expectations of postoperative outcomes.
Thursday's Best Papers
Low density pedicle screw constructs are associated with lower incidence of proximal junctional failure in adult spinal deformity surgery–Presenting author: Alan Daniels, MD
  1. What question is your research attempting to answer?
    Proximal junctional failure (PJF) following spinal deformity correction is a multi-factorial phenomenon, and select studies have shown that the rigidity of posterior spinal constructs may impact risk of PJF. Pedicle screw density may contribute to construct rigidity, and we sought to determine whether screw density was associated with PJF.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    Among ASD patients undergoing long-segment primary fusion to the pelvis, the risk of PJF was lower among patients with <1.8 screws per level. This finding may be related to construct rigidity. However, residual confounding by other patient and surgeon-specific characteristics may exist.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    These results are consistent with previous studies asserting that less rigid posterior spinal constructs may exhibit lower risk of PJF. If confirmed through additional studies, these results may support actionable change in surgical strategy although other factors would need to be monitored such as magnitude of deformity correction, rod fracture, etc.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    This study preliminary indicated that constructs with a lower density of pedicle screws may have lower rates of PJF, thus if this data is confirmed with further clinical data then this may provide yet another PJF prevention strategy.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    It is important to underscore the retrospective nature of this study. Residual confounding by other patient and surgeon-specific characteristics may exist. Further biomechanical and clinical studies exploring this relationship are warranted.

Incidence and resolution strategies for early onset postoperative leg pain following lumbar total disc replacement–Presenting author: Scott Blumenthal, MD
  1. What question is your research attempting to answer?
    We knew some patients undergoing lumbar total disc replacement (TDR) have onset of new leg pain after surgery without indication of nerve compression. We wanted to, in a formal study format, determine the incidence of this problem, its course, and provide information about its treatment.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    The incidence of early postop leg pain onset was about 10%. In the majority of patients, it resolves with medication and nonop care interventions.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    This is the first study to focus on this problem and strategies for its treatment.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    Surgeons can provide reassurance to patients that this problem occurs in about 10% of patients and generally resolves. The most common treatment is medication to facilitate resolution.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    Hopefully, surgeons will use this information to educate patients on the occurrence of early postop leg pain after lumbar TDR and what to expect if it does occur. It should also provide surgeons with a strategy for its treatment.

Why are DBMs so variable? Influence of fibers, carrier, and tissue bank–Presenting author: Gregory Mundis, MD5
  1. What question is your research attempting to answer?
    As surgeons, we typically have the choice of which bone graft material we choose to use. Many times a DBM is selected. Many surgeons and hospitals assume that all DBMs are similar, give or take minor variation… but is that really true? Are there differences? and if so, what is driving those differences?

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    We tested seven different DBMs under the same conditions in a well-published rat fusion model. Many of the DBMs appeared to be the same on paper with regard to white papers or marketing material, but we found profound differences in their ability to fuse a rat spine. If the DBM cannot fuse a rat spine then I am very concerned about its ability to fuse a human spine.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    The biggest surprise was that composition alone wasn’t enough to predict the performance of the material. DBM fibers made a difference, the lack of carrier made a difference, but the biggest difference seems to come from which tissue bank made the DBM and their particular methods of processing the bone.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    There are many practical challenges that limit the ability to run well-designed clinical studies comparing different DBM products. Without that level of data, preclinical evidence is the most valuable information that we have for making informed decisions that help us get the best fusions for our patients. This study will help surgeons in their clinical decision-making regarding DBM selection and help give them foundational knowledge to critically assess which grafting material they choose to use.

  5. Is follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    A great topic for a budding researcher would be to attempt to correlate results in a rat to expectations in humans. This data does not exist yet. Secondly, further analysis could be performed as it relates to cost and the implications for the payor and patient.
Rates of loosening, failure, and revision of iliac fixation in adult deformity surgery–Presenting author: Robert Eastlack, MD
  1. What question is your research attempting to answer?
    Pelvic fixation for adult spinal deformity has evolved over many years to include different types of iliac fixation (iliac bolts, S2 alar iliac bolts), metallurgy (stainless steel, cobalt chromium, titanium alloy) and numbers of fixation points (one vs two iliac screws, unilateral, bilateral), among others. In addition, pelvic fixation that bypasses or transgresses the sacroiliac joint has an undetermined impact on the function and clinical outcome of that joint. In the context of known continued mobility of the sacroiliac joint following adult spinal deformity surgery, and the biomechanics stresses appreciated by lumbopelvic fixation following deformity surgery, we aimed to determine the actual types and rates of failure of fixation in this setting within a large group of patients treated by a variety of surgeons specializing in adult spinal deformity correction.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    Our results demonstrate a substantial rate of pelvic fixation failure following correction of adult spinal deformity. Lumbopelvic fixation failure occurred at a rate of 29.4% following surgical correction of ASD when iliac fixation was utilized, and this was associated with diminished clinical outcomes as measured by HRQL at 2 years postoperatively. These findings suggest that benefits from surgical correction of adult spinal deformity deteriorate in a substantial portion of patients, potentially as a result of limitations in lumbopelvic fixation as currently employed. These erosions in HRQLs may negatively impact the cost-effectiveness of adult spinal deformity when evaluated over a longer period of time.

    Additionally, S2AI screws were more likely to demonstrate loosening, but less commonly associated with rod fractures. This may imply varied mechanical stresses that occur as a result of crossing vs bypassing the sacroiliac joint, and may result in a need to apply different solution strategies depending on the type of iliac fixation to be utilized.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    Determining such a high rate of fixation failure around the lumbopelvic region with a large patient cohort provides us with tremendous opportunity to identify solutions that will dramatically improve patient care in the future. Adult spinal deformities are some of the most disabling of conditions, and yet the patients have profound improvements with proper correction. Because these surgical corrections are extraordinarily resource intensive, ensuring that we have sustainable and optimized clinical and radiographic outcomes that minimize the need for future surgical intervention will be profoundly positively impacted by the information from this study, and those that follow from it.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    Fixation failures in this region will potentially result in deteriorating or poorer clinical outcomes, as well as leading to revision surgery, both of which have serious implication for the cost-effectiveness of the index surgeries. Furthermore, by better understanding the specific nature and sources of these failures, we can more effectively strategize in preventing them during the index surgeries. This may be through a combination of tactics, to include variations in rod numbers, screw number, screw location, screw-rod interface type, screw dimensions, rod dimensions, rod metallurgy, sacroiliac joint constraint, optimization of lumbopelvic alignment goals and type of interbody device at the lumbosacral junction.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    We intend to do further work on this subject in a prospective manner to better understand the implications of these constructs and failures on clinical symptoms and behavior of the sacroiliac joint following deformity reconstruction. This will require diagnostic maneuvers that were not available to us with our original prospectively captured cohort. Additionally, we intend to further research areas of failure within the implants themselves, so that we can provide guidance regarding minimum tolerances of the implants for use in lumbopelvic fixation, to include issues such as rod diameter, screw neck diameter, screw shank diameter, type of screw head and others.

Cell stiffness decreases with severity of disc degeneration and inflammatory stimulation–Presenting author: Ronald Lehman, MD
  1. What question is your research attempting to answer?
    Here we look to answer the question of how are the biomechanics of individual intervertebral disc cells affected during the progression of disc degeneration? And how do these changes in cell properties contribute to the degenerative cascade?

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    Here we show increasing degree of degeneration corresponds to decreased cell stiffness and increased cell hydraulic permeability. These changes are consistent with those seen with inflammatory stimulation of disc cells and supports the hypothesis that elevated pro-inflammatory activity in vivo may contribute to altered mechanobiology of disc cells.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    This is the first report that evaluates single cell biomechanics from disc patient samples. Both inflammatory stimulation and mechanical injury have been shown to lead to similar degenerative effects within the IVD. The work here provides a crucial link between inflammatory stimulation and altered cell mechanics in human disc degeneration.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    The findings of this research contribute to our basic science understanding of disease and open up the need to consider therapies to protect cell integrity. The measurement of cell biomechanics could also be potentially used as a diagnostic test.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    Future studies expand the data set here, and will investigate the efficacy of using novel drugs to protect cell properties during degeneration in pre-clinical and eventually clinical models.

Is academic department teaching status associated with adverse outcomes after lumbar fusion for degenerative spine diseases?–Presenting author: Dean Perfetti, MD, MPH
  1. What question is your research attempting to answer?
    Concerns have been raised regarding the quality of care performed at teaching hospitals versus their non-teaching counterparts. In the setting of increasing health care costs, it is imperative that the stakeholders involved in formulating payment models incentivizing cost efficiency understand the outcomes associated with teaching status and risk stratify the payment models accordingly. In this study, we compare the following outcomes for lumbar spinal fusion according to teaching status: (1) length of stay; (2) costs; (3) disposition to facility; (4) 30-day and 90-day readmission; (5) 30-day, 90-day and 1-year return to the operating room. Given the results of prior studies, it was hypothesized that academic teaching hospital status would negatively affect the outcome measures, with longer length of stay, increased costs, increased disposition to rehabilitation, increased readmission and increased return to operating room rates.

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    Teaching hospitals experienced greater costs, length of stay, discharge to rehabilitation and readmission rates (p<0.001). Teaching hospitals had decreased odds of return to the operating room at 30 days, 90 days and 1-year post index fusion (p<0.001). Given the increasing prevalence of lumbar spine procedures in recent years, it is important to maximize patient outcomes while controlling cost. In doing so, it is imperative to recognize the importance of teaching institutions and to be aware of potential financial impacts of resident education. The findings of this study suggest that although teaching hospitals performing lumbar fusions have inefficiencies, they may benefit from reimbursement tied to competition on clinical outcome and value-based metrics. Teaching hospitals do not compete well on cost efficiency metrics. Stake holders and designers of alternative payment models should consider the inefficiencies of teaching hospital status on surgical outcomes and stratify payment models accordingly.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    Current literature provides conflicting results in regards to teaching status and fusion outcomes. What makes our study’s findings so powerful is the volume of patients we are comparing (tens of thousands), with stringent inclusion and exclusion criteria allowing us to appropriately compare teaching versus non-teaching hospitals for a specific domain of spine surgery, ie, lumbar fusion for degenerative spine disease. We believe our results are relevant to the spine community, and are not meant to discourage patients from getting their surgeries performed at teaching or non-teaching facilities, but to facilitate further research and questions at the institutional level in regards to teaching status and outcomes given the study’s findings that teaching hospitals perform poorly on cost metrics but favorably on the clinical outcome of reoperation.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    Given the increasing prevalence of lumbar fusion procedures in recent years, it is important to maximize patient outcomes while controlling cost. In doing so, it is imperative to recognize the importance of teaching institutions, and to be aware of potential financial and other impacts on resident education. The findings of this study suggest that although teaching hospitals performing lumbar fusions have inefficiencies, they may benefit from reimbursement tied to competition on clinical outcomes and value-based metrics.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    Spine specialists and hospital administrators should use our study’s findings as the impetus to assess their lumbar fusion outcomes at teaching and non-teaching sites. Moreover, they should attempt to delineate etiologies for cost disparities at the institutional level, and observe long-term outcomes between teaching and non-teaching sites.

Nanoroughened microstructured orthopaedic implant surfaces induce osteogenesis via soluble signaling factors produced by MSCs–Presenting author: Michael Berger, BS
  1. What question is your research attempting to answer?
    In the present study, we sought to answer the question, “Can bone marrow stromal cells (MSCs) grown on microtextured and nanostructured biomimetic surfaces differentiate into bone forming osteoblasts and regulate cells in the native tissue to increase bone formation around a titanium-based implant?”

  2. Please summarize your key findings and comment on the clinical significance (if applicable)...
    MSCs cultured on microtextured and nanostructured Ti6Al4V surfaces differentiate and produce local factors that can induce MSC differentiation away from the implant surface through paracrine signaling factors such as bone morphogenetic protein 2 (BMP2). The in vitro cell culture model shows that nanotextured microstructured biomimetic surfaces induced local factor production, including BMP2. Factors present in the media of MSCs grown on these surfaces increased bone formation in an in vivo mouse model compared to control and BMP2-alone treatment groups. This indicates that the surface topography has an osteoinductive effect via surface-dependent osteogenic differentiation of the MSCs, potentially supporting better osseointegration and may provide an alternative to expensive pharmacologic agents like rhBMP2 for patients with compromised bone quality.

  3. What is surprising/exciting/different about your research results? (For example, do they affirm or debunk any existing spine treatment or diagnosis?)
    Here we show that synthetic biomaterials with implant surface properties that mimic the properties of native bone tissue are capable of regulating the natural process of implant integration. Clinically this is extremely important for creating implants that can improve implant retention rates and healing times for patients with compromised bone qualities, without the need to excessive pharmacologic intervention.

  4. How can this research ultimately apply to or benefit spine patients? (Will it make diagnosis/treatment/payment any easier/less expensive/better in the future?)
    This research will ultimately help improve implant osseointegration without the use of exogenous bone augmentation factors like rhBMP2, this in turn can reduce surgical costs and mitigate potential complications from supraphysiologic doses of rhBMP2.

  5. Is there follow-up research or work needed that can help shine additional light on this topic? Or, now that spine specialists know this, what should they do about it?
    phases of the complex processes of implant integration such as immune regulation, and how these properties regulate the interaction between bone forming osteoblasts and bone degrading osteoclasts. For example, do MSCs produce factors other than BMP2 on biomimetic surfaces that contribute to osteogenesis and implant integration.