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Friday, October 24, 2014

As healthcare-resources become more limited, the spine community has focused more on improving the value of care. Value is defined as quality/cost, so either improving quality without increasing cost or maintaining quality while decreasing cost can both increase value. Many efforts towards improving value have involved creating evidence-based pathways to standardize care in a manner that maximizes quality in a cost-effective manner. In the treatment of low back pain (LBP), advanced imaging and surgeon referral are two high cost items, and current guidelines suggest that most LBP patients need neither.1 In the United States, there are no formal controls over advanced imaging or surgeon referral, and both are readily available without long wait times. However, in many single-payer systems such as in Canada, MRI scanners and spine surgeons are in relatively short supply, which creates long wait times for both. While efficient use of expensive resources should be the goal of any health system, the motivation for improved triage of LBP patients to advanced imaging and spine surgery consultation is stronger if access is difficult. In order to improve the rate of appropriate use of advanced imaging and surgeon referral, the Saskatchewan Ministry of Health created the Saskatchewan Spine Pathway that allows PCPs to classify patients as having one of four pain patterns (LBP worsened with flexion, LBP worsened with extension, predominant leg pain that is constant and mechanical, and predominant leg pain with extension) based on the history and a brief physical exam. They then suggest self-care exercises specific for each pain pattern and refer patients to a physical therapist-run spine clinic if they fail to improve quickly. The therapists then re-assess the patients and refer the leg pain predominant patients for MRI and surgical referral if self-care is not helping, while they coordinate non-surgical care of the predominant back pain patients. After instituting this pathway, the authors retrospectively evaluated the rate of appropriate surgical referrals for patients treated on the pathway and those referred via the traditional process. They found that 60% of patients referred via the pathway were surgical candidates compared to 37% referred via the traditional process. The authors noted that historically only 15% of surgeon referrals were surgical candidates, though prior to the start of the study, the PCPs had undergone training in appropriate surgical referrals, which seemed to have improved the process to some degree. Additionally, 75% of the patients referred via the pathway had predominant leg pain compared to 55% referred via the traditional process.


This study suggests that the use of scarce and expensive resources such as MRI scanning and spine surgeon referral can be made more efficient through the use of a non-MD staffed triage clinic, which has likely improved the value of spine care in Saskatchewan. While health services research such as this is outside the realm of traditional basic science or clinical outcomes studies, this type of work is going to become increasingly important as we strive to improve value in healthcare. This analysis was unblinded, non-randomized, and retrospective, so the results should be viewed as preliminary, but the findings support the experience of most spine surgeons. The majority of spine surgeons in the United States have likely developed some form of triage system within their practice to increase the likelihood that the patients they see are candidates for surgery. However, very little has been written about this topic that is very important to providers trying to run an efficient clinic. The challenge in the United States with its decentralized healthcare system is to motivate referring PCPs to engage in such a program. It is much easier for a PCP to simply order an MRI and refer a patient with chronic LBP to a spine surgeon than trying to classify their pain pattern and start a self-care program. While such PCP engagement may not be possible outside of centralized health systems, the establishment of algorithm-driven, non-MD triage clinics could potentially improve the rate of appropriate imaging and surgical referral and substantially decrease costs. Quality may also improve as chronic LBP patients would probably be less likely to be subjected to ineffective pharmacological and interventional treatments, and patients with radiculopathy and claudication could be referred to a surgeon more rapidly. As individual practices consolidate into larger practice organizations in the United States, developing more organized care pathways such as this may become more of a reality. Hopefully further data from Saskatchewan will be emerging including the effect of the pathway on appropriate use of advanced imaging and on the cost of treating these patients.


Please read Ms. Wilgenbusch’s article in the October 15 issue. Does this article change how you view the triage of LBP patients? Let us know by leaving  a comment on The Spine Blog.


Adam Pearson, MD, MS

Associate Web Editor



1.            Chou R, Qaseem A, Snow V, et al. Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society. Ann Intern Med 2007;147:478-91.


Friday, October 17, 2014

The indications for the use of bone morphogenetic protein (BMP) in spinal fusion remain unclear. While prior studies have shown an increased radiographic fusion rate, there is little data to suggest lower re-operation rates or better patient reported outcomes when used in good fusion environments such as single level posterolateral instrumented lumbar fusion.1,2 Additionally, BMP may be associated with complications such as increased post-operative pain, edema and airway compromise in the anterior cervical spine, retrograde ejaculation in the anterior lumbar spine, graft subsidence, and possibly cancer. In order to add further data to the BMP discussion, Dr. Guppy and his colleagues at Kaiser Permanente used their spine surgery registry to determine reoperation rates for nonunion among over 9,000 spinal fusion patients, including every region of the spine. For patients with at least one year of follow-up, the overall reoperation rate for nonunion was 1.9% for BMP patients and 2.2% for non-BMP patients. These rates increased to 2.3% and 2.6%, respectively, for those with at least 2 years of follow-up. The BMP and non-BMP groups were markedly different, with the BMP patients being older, including more females, more deformity, spondylolisthesis, and post-laminectomy syndrome patients, more likely to have undergone long thoracolumbar fusion, and less likely to have undergone cervical fusion. The authors created a Cox regression model to control for these differences, which demonstrated a 33% reduction in reoperation for nonunion for the BMP patients, but this difference was not significant.


This paper supports prior studies that have suggested that BMP use does not reduce reoperation rates in most fusion environments. The conclusions that can be made from this study are limited by the typical shortcomings of administrative databases, which are even more pronounced when the two groups being compared are so different at baseline. Given these differences in measured characteristics, one must assume that they are also different in unmeasured characteristics (i.e. smoking, prior surgery, psychosocial characteristics, etc.) for which the analysis cannot be controlled. Additionally, the indications for reoperation for nonunion are very variable among surgeons and also depend on patients’ willingness to undergo reoperation. The use of BMP is also markedly variable among surgeons, so the relationship between BMP use and reoperation is likely confounded by the individual surgeons making these decisions. Reoperation for nonunion is also a relatively rare event (under 3% over 2 years in this study), which results in very limited power to perform subgroup analyses even when starting with nearly 10,000 patients. While this study does have limitations, it adds data to the growing pile of evidence suggesting that BMP is not indicated for straightforward fusion operations in good fusion environments where the likelihood of fusion is high without it. The spine community has yet to determine where it might be of benefit, though some data as well as general principles suggest that it may make a positive difference in challenging fusion environments such as long deformity constructs or established nonunion.3


Please read Dr. Guppy’s article in the October 15 issue. Does this paper change how you see the role of BMP in spinal fusion? Let us know by adding a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor




1.            Fu R, Selph S, McDonagh M, et al. Effectiveness and harms of recombinant human bone morphogenetic protein-2 in spine fusion: a systematic review and meta-analysis. Annals of internal medicine 2013;158:890-902.

2.            Simmonds MC, Brown JV, Heirs MK, et al. Safety and effectiveness of recombinant human bone morphogenetic protein-2 for spinal fusion: a meta-analysis of individual-participant data. Annals of internal medicine 2013;158:877-89.

3.            Kim HJ, Buchowski JM, Zebala LP, Dickson DD, Koester L, Bridwell KH. RhBMP-2 is superior to iliac crest bone graft for long fusions to the sacrum in adult spinal deformity: 4- to 14-year follow-up. Spine 2013;38:1209-15.


Friday, October 10, 2014

Surgical treatment of metastatic and primary spinal tumors is complex and associated with high complication rates. While surgery of this magnitude would be expected to result in a high complication rate in healthy patients, spinal tumor patients typically have multiple comorbidities and in many cases compromised immune systems and soft-tissues due to chemotherapy and radiation. This creates a perfect storm for generating complications by combining complex surgery with sick, deconditioned patients. Recently, the Center for Medicare and Medicaid Services (CMS) has begun to levy financial penalties on hospitals with high readmission rates for certain diagnoses, which has created an even heightened awareness about readmissions. On this background, Dr. Ames and his colleagues from UCSF reviewed 197 cases of metastatic (83%) and primary (17%) spinal tumors from 2005-2011 in order to evaluate 30 day and 1 year readmission rates as well as risk factors for readmission in this population. The overall 30 day readmission rate was 14% (17% for metastatic patients), with a one year overall readmission rate of 31% (38% for metastatic patients).  Patients with metastatic disease had a one year mortality of 30%, and 40% of Tokuhashi Group 0 patients (i.e. osteosarcoma, lung, stomach, bladder, esophagus, and pancreas cancer) died within a year of surgery. Medical complications were the most common cause of readmission (43%), while 33% of readmissions were due to recurrent disease and 23% due to surgical complications. Diabetes, obesity, pulmonary circulatory disease, depression, and operative time over ten hours were all independent predictors of readmission, and normal ambulatory function at baseline decreased the odds of readmission by 50%.


The high rate of readmission and mortality following surgical treatment of spinal tumors comes as no surprise. No other result could be expected when deconditioned patients with metastatic cancer—many of whom also have neurological deficits—are subjected to surgeries that involve one to three liters of blood loss and 8-14 hours in the operating room. These results are likely generalizable to other tertiary care centers performing spine tumor surgery. While UCSF represents a high volume center, they only performed about 30 cases of spinal tumors per year, indicating that these cases are not that common. The results of this paper, which might be used as a benchmark against which other centers could be compared, could have policy implications. If CMS begins to penalize hospitals for all readmissions without appropriate case mix adjustment, tertiary care centers will be disincentivized to provide this type of complex care. With relatively few centers performing spine tumor surgery, patients could find even less access to care for this challenging problem. Hopefully these data will illustrate the high rate of complications, readmission, and mortality inherent in spinal tumor surgery and prevent the creation of financial penalties for institutions and providers that care for cancer patients. Society has difficult decisions to face in cancer care. Chemotherapeutic drugs and surgical treatment of cancer are oftentimes not cost effective in the traditional sense (i.e. cost per quality adjusted life year), though life can sometimes be prolonged and quality of life improved. The amount we should spend on terminal cancer care will continue to be debated as healthcare resources become scarcer.

Please read Dr. Ames article on this topic in the October 1 issue. Does this change how you view the surgical treatment of spinal tumors? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor

Friday, October 03, 2014

Most previous literature has indicated that smoking increases pseudarthrosis rates in both the lumbar and cervical spine.1,2 The effect of smoking on complications is less clear, in part because literature on this topic has typically controlled for the effects of medical comorbidities that result from smoking, an analytical approach that yields results that are difficult to interpret (i.e. controlling for COPD and heart disease results in no association between smoking and complications) .3 In an effort to better understand the effect of smoking on one and two level lumbar fusion, Dr. Bydon and colleagues from Johns Hopkins retrospectively reviewed 281 cases from 1990-2011 to determine the association between smoking and post-operative complications, including pseudarthrosis. Approximately half the patients had one level fusions, about half received BMP, and 18% were smokers (n=50). The authors reported a non-significant increased risk of pseudarthrosis in smokers overall (18% smokers vs. 10% non-smokers), with the strongest association between smoking and pseduarthrosis observed in patients undergoing two level fusion (29% vs. 10%, p = 0.02). The overall risk of complications was relatively low—around 5%--and was not significantly different between smokers and non-smokers. There appeared to be a non-significant trend towards an increased risk of complications for smokers in one level fusion (OR=1.9), however, only 2 smokers in this group had complications, so the comparison was clearly underpowered. Based on these data, the authors concluded that smokers were not at higher risk for complications other than pseudarthrosis after two level fusion.


This paper does add support to the already large body of evidence indicating that smoking is associated with pseudarthrosis. However, this paper has marked limitations making it difficult to interpret the comparisons that showed no significant differences (i.e. pseudarthrosis rates for single level fusions and overall complication rates). The study is substantially underpowered, especially for the subgroup analyses looking at one and two level fusions separately—there were only about 25 smokers in each subgroup. Given the relatively low rate of complications (about 5-10%), there were nowhere close to enough patients to avoid Type II error. Additionally, BMP was used in about 50% of cases, and smokers were about 25% more likely to receive it. This confounds the results and could underestimate the effect of smoking on pseudarthrosis. The paper is limited by its retrospective nature, and data such as smoking status and complications had to be identified by chart review, a notoriously unreliable method of capturing data that may or may not have been accurately recorded. Even the definition of pseudarthrosis was somewhat vague and likely depended on what imaging studies were done and at what time point after surgery. This study does support the idea that the effect of smoking is likely modified by the specific fusion environment, with smoking being more strongly related to pseudarthrosis in challenging fusion environments such as multilevel fusions or uninstrumented fusions. While this and other studies may indicate that fusion rate may be less affected by smoking in one level instrumented fusions, it should not be used as a justification for patients to continue to smoke after fusion.


Please read Dr. Bydon’s paper on this in the October 1 issue. Does this change your view on how smoking affects fusion outcomes? Let us know by leaving a comment on The Spine Blog. 

Adam Pearson, MD, MS
Associate Web Editor




1.            Glassman SD, Anagnost SC, Parker A, Burke D, Johnson JR, Dimar JR. The effect of cigarette smoking and smoking cessation on spinal fusion. Spine 2000;25:2608-15.

2.            Hilibrand AS, Fye MA, Emery SE, Palumbo MA, Bohlman HH. Impact of smoking on the outcome of anterior cervical arthrodesis with interbody or strut-grafting. J Bone Joint Surg Am 2001;83-A:668-73.

3.            Seicean A, Seicean S, Alan N, et al. Effect of smoking on the perioperative outcomes of patients who undergo elective spine surgery. Spine (Phila Pa 1976) 2013;38:1294-302.


Friday, September 26, 2014

The best bone graft to achieve fusion in different fusion environments remains unknown, and the use of iliac crest bone graft (ICBG), once the standard graft choice, has markedly decreased with the development of bone graft substitutes and the increased use of instrumentation and local bone graft. There is good evidence that the use of allograft in the cervical spine and local bone in the lumbar spine yields fusion rates close to ICBG for one and two level fusions when instrumentation is used. The degree of morbidity associated with ICBG harvest is also unclear, with traditional teaching suggesting a relatively high rate of long-term donor site pain, but more recent studies suggesting this may not be the case. If the morbidity associated with ICBG harvest is actually low, it may be a more appealing source of graft given higher fusion rates and potentially lower costs. On this background, Mr. Gruskay and his colleagues from Yale analyzed all fusion patients captured by the National Surgery Quality Improvement Project (NSQIP) database from 2010-2012. This yielded nearly 14,000 patients undergoing anterior or posterior procedures in the cervical, thoracic, and lumbar spine. Only 6% of patients underwent ICBG harvest, with ICBG use most common in posterior fusion procedures (approximately 10% of posterior fusion patients had ICBG). Iliac crest was harvested more often in multilevel than single level cases, though it was used in a small minority of patients even in fusions involving three or more levels. Unadjusted analyses demonstrated ICBG was associated with a 130% increase in transfusion rate, a 0.6 day increased length of stay (LOS), and 35 additional minutes in the OR. Given that these data are confounded by surgical approach and number of levels fused, multivariate analysis controlling for these and other factors showed a 50% increase in transfusion rate, a 0.2 day increased LOS, and 22 additional minutes of operating time if ICBG was harvested.


The results of this paper confirm what most spine surgeons would expect—ICBG harvest takes 20 or 30 minutes, increases blood loss, and might prolong hospital stay in a small number of patients who get a transfusion or have increased post-operative pain. The real questions about ICBG—does it cause long-term donor site pain, decrease re-operation rate due to higher fusion rates or save money—cannot be answered with this study design. Most surgeons would expect that there is some downside to ICBG harvest, namely that it takes some time, increases blood loss, and might increase pain, and this study confirms some of this. In one and two level instrumented fusions, it seems as though the potential benefits of ICBG probably do not outweigh the negatives when compared with allograft or local bone graft. The most burning question is whether ICBG, local bone graft plus extenders, or BMP is the best graft for fusions including at least 3 levels. That question remains open, though there is some recent data from the deformity world suggesting BMP may have some advantages over ICBG. Given the current data that suggests fusion rates for one and two level instrumented fusions are reasonably high with allograft and/or local bone, it is not surprising that ICBG has fallen out of favor.


Please read Mr. Gruskay’s article on this topic in the September 15 issue. Does this change your views on ICBG? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor


About the Blog

Spine Journal
This Blog provides a forum for discussion about high impact articles published in Spine, including the bi-annual publication of "Evidenced-Based Recommendations for Spine Surgery." Website users can use this forum to discuss how the articles have affected their practice and query the authors about their findings and recommendations.