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The Spine Blog

Friday, January 11, 2019

While the role of fusion in the surgical treatment of degenerative spondylolisthesis remains controversial, most spine surgeons agree that a solid fusion is preferable to a pseudarthrosis.1-3 Investigators have demonstrated that pedicle screw instrumentation, iliac crest bone graft, and BMP-2 increase fusion rates. Unfortunately, these are all associated with increased morbidity, increased cost, or both. As such, researchers have made an effort to identify lower risk alternatives to increase fusion rates. Teriparatide (synthetic parathyroid hormone, marketed as Forteo) has shown to be a promising medication that has improved fusion rate and quality in animal models. A non-randomized Japanese study compared fusion rate in osteoporotic women with degenerative spondylolisthesis treated with either teriparatide or risedronate around the time of lumbar laminectomy and instrumented fusion with local bone graft. The patients received the medication for two months pre-operatively and for eight months post-operatively. There was no control group that received placebo or no medication. They found that the 12-month fusion rate as determined by CT scan was higher in the teriparatide group (82% vs. 68%). Given these promising findings, Dr. Jespersen and colleagues from Denmark performed an RCT in which 101 degenerative spondylolisthesis patients over 60 years old undergoing one or two level decompression and uninstrumented fusion using local bone graft and allograft were randomized to 90 days of teriparatide or placebo. At one year, all patients underwent a CT scan to determine fusion rate, fusion mass volume, and fusion mass density. Overall, the fusion rate was 33%, and there were no significant differences between the two groups (29% teriparatide vs. 37% placebo). There were no differences in fusion mass volume or density. Based on these findings, the authors concluded that 90 days of teriparatide did not change the fusion rate or quality in this population.

The authors should be congratulated on successfully performing a Level 1 study that was well-designed to answer a specific clinical question. While RCTs provide the highest level evidence, they can only answer one specific question. Teriparatide seemed promising in animal models, and it may be helpful in different scenarios than the one studied here. This investigation looked at a specific dose, duration, and fusion technique, and it is reasonable to conclude that teriparatide was not helpful in this specific situation. It is possible that longer duration therapy, starting it months pre-operatively, using it with instrumented fusion, or using it strictly in a population of osteoporotic women would result in a different outcome, though these specific scenarios would need to be studied to answer the question. One of the striking findings of this study is that the overall fusion rate was only 33% with an uninstrumented fusion using local bone graft and allograft. Patient reported outcomes were not included in this study, but there is some evidence suggesting that long-term outcomes are worse in uninstrumented fusion patients who go onto nonunion.3 Given that many degenerative spondylolisthesis patients do well without fusion, it may be that nonunion does not have a markedly negative impact on their outcomes. It will be interesting to see the patient reported outcomes in this study population to determine if the patients with nonunion have worse outcomes. The role of teriparatide in lumbar fusion remains unclear, though this study makes it clear that it is not beneficial at this dose and for this duration in this population. The bigger question about the best surgical technique for degenerative spondylolisthesis patients remains unanswered. It seems likely that degenerative spondylolisthesis represents a disease spectrum and that patients with different characteristics do best with different operations, though how to determine the best operation for an individual patient remains unknown.

Please read Dr. Jespersen’s article on this topic in the February 1 issue. Does this change your view of teriparatide in lumbar fusion? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor


1.            Forsth P, Olafsson G, Carlsson T, et al. A Randomized, Controlled Trial of Fusion Surgery for Lumbar Spinal Stenosis. The New England journal of medicine 2016;374:1413-23.

2.            Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus Fusion versus Laminectomy Alone for Lumbar Spondylolisthesis. The New England journal of medicine 2016;374:1424-34.

3.            Kornblum MB, Fischgrund JS, Herkowitz HN, Abraham DA, Berkower DL, Ditkoff JS. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective long-term study comparing fusion and pseudarthrosis. Spine 2004;29:726-33; discussion 33-4.


Sunday, January 6, 2019

Qualitative research is frequently used in the social sciences but is rarely encountered in the spine surgery literature. Much has been written about the use of shared decision making to aid patients deciding about whether to undergo spine surgery, though there is scant literature about what the patient experiences during this process. This topic does not lend itself to traditional quantitative methods using patient reported outcomes and requires a qualitative approach. Dr. Andersen and colleagues from Denmark designed a qualitative study to evaluate patient perceptions regarding the decision to undergo lumbar discectomy. They interviewed 14 patients presenting with radiculopathy in the presence of an MRI-confirmed lumbar disk herniation to determine which factors affected their decision-making. Nine of the fourteen also underwent a second interview 1-2 months later. The interviewers asked them open-ended questions about the decision-making process and recorded the discussions. They then coded the patient statements according to themes, and the group arrived at four main themes that they observed across the interviews. The major factors that affected decision-making and how the patients experienced the process were the level of patient information, the effect of accelerated workflows, the power imbalance between clinicians and patients, and the patients' personal experiences with acquaintances who had been treated for a lumbar disk herniation. The investigators found that patients frequently had misinformation prior to meeting with a spine surgeon, and this misinformation affected their decision-making. Patients also reported feeling rushed through the process, which led some to decide to go ahead with surgery without feeling as though they had sufficient time to make the decision. Many patients reported feeling as though they would defer to the recommendation of the surgeon as they saw the surgeon as the expert whose opinion was more important than their personal preferences. Some based their opinion about discectomy on the spine surgery experiences of others they knew, which could be either positive or negative.

The authors have done a very nice job performing a qualitative analysis regarding the patient experience during decision-making around lumbar discectomy. Such studies are not common in the spine literature, and this type of analysis is key to getting at topics such as this. A traditional quantitative analysis using measures of decisional conflict and satisfaction with decision-making would have lost the meaningful information that can only be captured through interviewing. The results of this study are not surprising and are in-line with many studies looking at shared decision-making. The challenging aspect of this type of study is that most of the factors that made decision-making difficult were outside of the control of the clinicians. The misinformation that patients had prior to the spine consultation tended to be from the internet, non-spine clinicians, and other patients. Surgeons are familiar with correcting false information with patients, and this is a difficult, time intensive process. In reading the comments from the patients about power imbalance, it suggests that some patients do not necessarily see this as a problems but simply as the reality of the situation. They view clinicians as experts and seem happy to follow their advice. Many patients felt pressured to make a decision about surgery quickly, though this was indirect and more related to the scheduling process than actual pressure applied by the surgeons. Qualitative research is not well-understood by the spine community (or myself for that matter), and it seems to have a high risk of bias as the researchers determine the themes. This process is clearly shaped by their beliefs, and it is hard to know if the comments determined the themes or if the researchers had preconceived notions about the themes and found comments to support these categories. Despite these limitations, a qualitative design is likely the only way to study this topic. The results suggest that we still have a long way to go to reach truly shared decision making.

Please read Dr. Andersen's article on this topic in the January 15 issue. Does this change how you view the patient experience in deciding about a lumbar discectomy? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor

Saturday, December 29, 2018

As 2018 comes to a close, it offers an opportunity to reflect on some of the important issues facing spine care providers and researchers. In reviewing The Spine Blog topics for the year, a few important themes stood out. The role of fusion and optimal fusion technique for degenerative spondylolisthesis (DS) patients remains controversial since the 2016 publication of two RCTs reaching opposite conclusions about the benefit of fusion in DS. In July, Vail and colleagues published the results of a large database study that demonstrated patients undergoing laminectomy and fusion had higher initial costs and complication rates compared to the laminectomy alone patients, but the laminectomy alone patients also had higher post-discharge costs and a higher reoperation rate. Interestingly, the uninstrumented fusion patients had the highest rate of post-operative complications. The Spine Patient Outcomes Research Trial (SPORT) 8 year DS study was also published. This paper completed the long-term follow-up series for the three diagnostic groups studied by SPORT and may represent the last paper from that project. It demonstrated the persistent benefit of surgery compared to non-operative treatment for DS patients out to 8 years. In a subgroup analysis, it also showed no difference in outcomes between patients treated with a posterolateral instrumented fusion, an interbody fusion, or an uninstrumented fusion, though there was no randomization for this aspect of the study. There were not enough patients treated with laminectomy alone to compare their outcomes to those treated with laminectomy and fusion. Two-thirds of respondents to the quick poll on the Spine website favored laminectomy and fusion while one-third favored laminectomy alone for a patient with stenosis and a stable degenerative spondylolisthesis. While the evidence supporting surgical treatment for DS is now quite strong, the best operation for the condition remains undefined and likely varies depending on individual patient characteristics.

Another controversial topic that came to light after a December 2015 article in The Boston Globe is concurrent surgery, in which a surgeon runs two operating rooms at a time in order to increase efficiency. While the practice was not uncommon prior to the article, it was rarely discussed and was probably not well-understood by patients. The article brought the issue into the spotlight and resulted in Senate hearings and policy changes in hospitals across the country. In order to better understand how surgeons see the topic, Dr. Laratta and colleagues published the results of a survey asking spine surgeons to define the "critical" aspects of spine surgery, or, in other words, the steps for which the attending surgeon needs to be present. The majority felt that decompression, fusion, and instrumentation were all "critical" steps, while positioning, opening, and closing were not. Dr. Bryant and colleagues from UCSF surveyed parents of patients undergoing surgery for adolescent idiopathic scoliosis, and there was strong agreement that patients should be informed of overlapping or concurrent surgery and that they would not want their child undergoing surgery by a surgeon running two rooms. The quick poll on this topic on the Spine website also indicated that readers felt that concurrent surgery was not acceptable.

On a less controversial front, multiple articles focused on the use of pharmacologic agents in spine surgery in order to reduce blood loss. A February article by Dr. Nagabhushan and colleagues showed that TXA and batroxobin both reduced blood loss compared to placebo. Dr. Lu and colleagues published a meta-analysis evaluating TXA and aminocaproic acid that showed that these significantly reduced blood loss and reduced the transfusion rate by 40%. Spine surgeons have widely adopted these agents for major deformity surgery, but the indications for their use in smaller magnitude surgery has yet to be defined. Quick poll respondents reported that they tend to use these agents for major deformity surgery and multiple level fusions, and some also used them for single level fusion. These medications are now widely used in total joint arthroplasty and cardiac surgery. The spine surgery community will have to determine for which cases they are indicated.

Spine research continues to provide answers to important clinical questions, though it seems that there remain more questions than answers in the spine world. Hopefully we will continue to see high impact research published in Spine in 2019. Happy New Year from The Spine Blog!

Adam Pearson, MD, MS

Associate Web Editor

Friday, December 21, 2018

Overlapping and concurrent surgery was commonly performed by surgeons but not widely understood by patients until a much-discussed Boston Globe article on the topic was published a few years ago. The article highlighted the case of a patient who sustained a neurological injury during complex cervical spine surgery on a day on which the attending surgeon was running two operating rooms. This article raised public awareness on the topic and resulted in guidelines being published by the American College of Surgeons and the development of policies regarding the practice at most hospitals. One of the major concerns with overlapping and concurrent surgery was that patients were not adequately informed about the practice and this violated their informed consent. In order to get a better sense about patient perception of overlapping and concurrent surgery, Dr. Bryant and colleagues from UCSF surveyed the parents of 31 adolescent idiopathic scoliosis (AIS) patients undergoing posterior instrumented fusion. They defined overlapping surgery as cases where "non-critical" (i.e. opening, closing, positioning) portions overlapped and concurrent surgery as those where "critical" (i.e. pedicle screw placement, correction) overlapped.  Every family approached about the survey agreed to participate, yielding a 100% response rate. Sixty-one percent of the respondents were mothers, 78% had at least a college degree, and 82% had an annual family income in excess of $100,000, indicating this was a relatively wealthy, educated cohort. Essentially all of the respondents strongly agreed that they should be informed of overlapping or concurrent surgery. The group strongly disagreed that concurrent surgery was acceptable, and they felt almost as strongly about overlapping surgery. Offering the availability of a "back-up" attending surgeon or informing the parents of research reporting that overlapping and concurrent surgery was not associated with adverse outcomes did not significantly change their opinions about the practice. The parents also agreed that they would cancel surgery on the day of surgery if they were informed that the case would be overlapping or concurrent, and they were willing to pay a premium to avoid overlapping or concurrent surgery for their child. They also felt that trainees should not perform "critical" portions of the case even when supervised and that "non-critical" portions of the case should be supervised by the attending. They had similar feelings about anesthesia providers. 

This article does a nice job pointing out the disconnect between surgical practice and patient preferences. While overlapping or concurrent surgery may not be common in AIS cases, it likely occurs in busy centers. Additionally, the parents felt strongly that trainees should not be performing "critical" portions of the case even under direct supervision, and that they should not be opening or closing without attending supervision. In most AIS cases performed at academic institutions, trainees do place pedicle screws under direct supervision and also close wounds without attending supervision. It may be that respondents would have different opinions on these topics if asked about spine surgery on themselves, and their responses about their children's surgery may be more conservative. There is a constant tension between providing the best, safest care possible, the need to train the next generation of surgeons, and a desire to use the operating room in the most efficient way possible. Little to no evidence exists to suggest that the involvement of properly supervised or even unsupervised trainees results in worse outcomes. However, parents of AIS patients clearly prefer to minimize the involvement of trainees. They are also clear in their rejection of the concept of overlapping and concurrent surgery. While adult patients may be more willing to accept trainee involvement or overlapping surgery for themselves, it seems highly unlikely that any patient would be enthusiastic about undergoing concurrent surgery. The American College of Surgeons, CMS, and most hospitals have guidelines against concurrent surgery, but the practice persists. Given the disconnect between current surgical practice and patient preferences, work needs to be done on hospital policy and patient education to get all parties on the same page. While this may come at the cost of resident/fellow education and attending surgeon compensation, surgeons have an ethical duty to inform patients of their practice and let them decide for themselves about whether or not they want to have overlapping or concurrent surgery or resident involvement in their case.

Please read Dr. Bryant's article on this topic in the January 1 issue. What are your thoughts on overlapping and concurrent surgery? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor

Sunday, December 16, 2018

People love lists of the best and most popular, especially at the end of the year, so it is fitting that Dr. Badhiwala and colleagues from Canada published their list of the Top 100 most cited papers published in spine journals in the December 15 issue. Similar lists have been generated over the years, though this one looked specifically at journals with the word "spine" or "spinal" in the title, and excluded works published in more general medical (i.e. New England Journal of Medicine) or orthopaedic (i.e. Journal of Bone and Joint Surgery) journals. Of the top 100, 84 were published in Spine, with the European Spine Journal finishing a distant second with 7 of the top 100 most cited articles. Seventy-three of the articles were published between 1990 and 2004, with only 2 having been published after 2010. This demonstrates that articles must be present in the literature for many years in order to generate high numbers of citations. The fact that fewer papers on the list predate 1990 is likely due to the high rate of growth of the number of publications—and thus citations—after this point in time. Not surprisingly, three of the top 5 most cited articles describe outcome measures (i.e. Roland-Morris Disability Questionnaire, Oswestry Disability Index, and SF-36), and these papers are generally cited in any subsequent study using the outcome measure. Guidelines for conducting research and clinical practice guidelines are also widely cited.  Somewhat surprisingly, 12 of the top 100 cited papers are lab studies (i.e. biomechanics, basic science of pain mediators), which rarely result in any change in clinical practice. In terms of subject matter, 22 of the top 100 dealt with low back pain, and an additional 12 focused on degenerative disk disease. There were 13 biomechanics papers in the top 100. The authors noted the paucity of cervical spine papers in the top 100, and there were only 5 cervical papers on the list.

The studies on this list come as no surprise. Classic studies describing specific patient reported outcome measures, research and clinical practice guidelines, classification systems, and surgical techniques made up the majority of the list. There are some notable studies that did not make the list, including the Maine Lumbar Spine Study, the Spine Patient Outcomes Research, and Herkowitz's classic study comparing laminectomy and fusion to laminectomy alone for degenerative spondylolisthesis. Many of these studies were published in general medical (NEJM, JAMA) or orthopaedics journals (JBJS), so they were not included. The 4 and 8 year follow-up studies from SPORT were published relatively recently, and there has not been sufficient time for them to accrue high numbers of citations. Somewhat disappointingly, only 8 of the top 100 papers were RCTs. This points out the difficulty of carrying out Level 1 studies on spine topics, and hopefully more will be forthcoming in the future. Many of the RCTs were also published in non-spine journals. This list serves as a jumping off point for creating bibliographies and reading lists of classic spine articles. The authors indicated they would be publishing a companion study that would include the non-spine specific journals, and such a study would make the list more complete. Please read Dr. Badhiwala's article in the December 15 issue. Are you surprised by any of the papers on this list or the papers missing from it? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS
Associate Web Editor