Skip Navigation LinksHome > Blogs > The Spine Blog
The Spine Blog
Friday, July 31, 2015

Disk degeneration (DD) and Modic changes (MC) have been shown to be associated with low back pain (LBP) in many, but not all, population-based studies. These disparate findings could have been related to different ways of measuring low back pain and disability and different patient populations under study. In order to clarify the association between DD, MC, and LBP, Dr. Maatta and colleagues used data from the TwinsUK database, that included T2-weighted MRI images on 823 patients at baseline, with 429 having a follow-up MRI at an average of 10 years after the initial scan. The vast majority of the population was women (96%), and the average age at baseline was 54. Unlike most prior studies, they defined “disabling low back pain” as one or more episodes of LBP lasting for at least 1 month, which limited basic activities such as walking around the house, standing for more than 15 minutes, getting in and out of a car, or going up and down stairs. Disk degeneration was categorized on a 0-20 point scale based on disk height loss, signal intensity change, posterior disk bulge, and anterior osteophytes. In univariate analysis, they found that age, BMI, DD, and MC were all associated with having an episode of LBP, with MC patients having more than double the risk at baseline compared to the non-MC group (35% vs. 16%). Multivariate analysis demonstrated that age, DD, and MC remained independent predictors of disabling LBP, with the presence of MC increasing the odds of LBP by 57%. Not surprisingly, there were strong correlations between DD and MC, with disk height loss and disk signal intensity change being associated with baseline MC, while disk height loss and posterior disk bulge predicted the development of MC.

 

The authors should be congratulated on their ISSLS award winning paper  demonstrating that MC is a strong, independent risk factor for having experienced disabling LBP. Compared to prior studies that usually defined LBP based on pain scales, this study was unique in looking at episodes of disabling LBP. Given that LBP can wax and wane, a patient’s pain rating on a given day may not reflect their long-term back condition, so a strict definition of having suffered an episode of disabling LBP is probably more meaningful. Interpreting the statistics is somewhat difficult as DD and MC are reported to be independent predictors of disabling LBP, yet their presence is strongly correlated. This implies they are part of the same degenerative process, but the presence of MC increases the risk of disabling LBP beyond the presence of DD alone. The two major limitations of this paper are the inability to characterize the type of MC (no T1 images were available for analysis) and the homogenous patient population (middle-aged women in the UK). This makes it difficult to know how different types of MC are associated with symptoms, though Type I MC are the most common and the type most associated with pain in prior studies. The strength of association implies that the results are probably generalizable, but it is important to repeat this study in other groups to confirm this. What this paper does not tell us is how the presence or absence of MC should affect how we treat the LBP population. Does the presence of MC predict better or worse outcomes with medication, PT, surgery or even antibiotics? Now that multiple studies have confirmed that MC is associated with pain and disability, future studies should determine if their presence or absence can help guide treatment for this challenging and common clinical problem.


Please read Dr. Maatta’s article in the August 1 issue. Does this change how you interpret Modic changes? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor    


Friday, July 24, 2015

The literature has made it very clear that workers’ compensation (WC) patients and patients involved in personal injury litigation who undergo treatment for spinal and orthopeadic disorders have worse outcomes. The causes behind these worse outcomes are complex and not fully understood but likely involve secondary gain issues, different psychosocial and disease characteristics, and possibly less stringent surgical indications for WC patients due to the higher reimbursement in this population. New Zealand has a different approach to compensating patients who are injured at work, in motor vehicle accidents, sports, and other activities. They have a state-run Accident Compensation Corporation (ACC) that insures the entire nation for injuries in a no-fault system. Such an approach effectively eliminates litigation and disputes between injured workers and employers. Dr. Robertson, a spinal surgeon from Auckland, and his colleagues decided to review outcomes between his ACC and non-ACC fusion patients who underwent surgery from 1997-2006. In New Zealand, the ACC patients are comparable to the WC and personal injury litigation patients in the United States with the exception that in New Zealand there are no adversarial legal proceedings related to their claim. All patients underwent lumbar fusion for isthmic spondylolisthesis, degenerative disk disease, or the need for wide foraminotomies requiring fusion to prevent instability. The primary outcome measures were the Roland-Morris Disability Questionnaire and the Low Back Outcome Score recorded at baseline, 1 year, and final long-term follow-up (average 8 years). The ACC patients were more likely to be male, approximately 8 years younger, more likely to have degenerative disk disease or foraminal stenosis, and less likely to have isthmic spondylolisthesis. The ACC patients had significantly worse baseline and one year patient reported outcomes, though long-term outcomes were similar. Change scores were similar between the ACC and non-ACC groups, and a similar proportion in each group improved beyond the minimal clinically important difference (MCID).

 

Assuming that ACC patients in New Zealand are similar to WC and personal injury litigation patients in the United States, these results are surprising. One would expect similar outcomes for WC and ACC patients, but, in New Zealand, the ACC patients tend to improve approximately the same amount as non-ACC patients. These results are markedly different to those found in the United States, Canada, Europe, and Asia for WC patients, whose lumbar surgical outcomes are worse than non-WC patients. While the WC system in the US is technically “no fault”, it is frequently involves an adversarial process in which patients require legal representation to negotiate with employers and workers’ compensation insurance companies in order to receive benefits. This paper makes it seem as though this is not the case in New Zealand. The New Zealand system also seems as though it could have secondary gain issues given that workers are reimbursed 80% of their typical pay while they remain out of work, though it is unclear for how long benefits last and how patients are encouraged to return to work. An interesting distinction between the two systems is that in the United States WC insurance typically reimburses medical providers at nearly 3 times the rate of non-WC insurance, while in New Zealand it tends to reimburse at 75% of non-ACC rates.1 Given these differences in reimbursement, US surgeons might loosen their indications for surgery given the higher reimbursement rates, which would likely lead to worse outcomes. The sociological causes for the apparently better outcomes for ACC patients in New Zealand compared to WC patients from other countries are not made clear by the current paper. This paper represents the practice of a single surgeon, and it is unclear if such results are obtained by other New Zealand surgeons. A larger, multicenter study would be needed to determine if these results are representative for all of New Zealand. If that is the case, a deeper sociological dive into the topic could provide important lessons for other countries with more adversarial WC and personal injury systems.

Please read Dr. Robertson’s article on this topic in the July 15 issue. Does this change how you think about the WC system in your country? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor

 

REFERENCE

1.            Tabaraee E, Ahn J, Bohl DD, Elboghdady IM, Aboushaala K, Singh K. The Impact of Worker's Compensation Claims on Outcomes and Costs Following an Anterior Cervical Discectomy and Fusion. Spine (Phila Pa 1976) 2015;40:948-53.

 


Friday, July 17, 2015

The medical literature is replete with studies demonstrating poor patient retention of information provided to them by doctors. Unfortunately, this has also been shown to be true for the surgical consent process. While poor patient recall is always a problem, it creates a medicolegal risk when patients do not recall potential complications. Most surgeons can recall a discussion with a frustrated patient—either their own or someone else’s—in which the patient states “You/they never told me this could happen!” Referral back to the consent document generally shows this not to be true, but when making decisions about litigation, patient perception tends to be more powerful than reality. Given the high rate of complications in adult spinal deformity (ASD) surgery, Dr. Saigal and colleagues studied patient recall of 11 potential complications that had been discussed by a surgeon and reinforced by a video. Immediately after the discussion, the median patient recalled 5/11 (45%) complications. Median recall dropped to 18% by 6 to 8 weeks and stayed there out to one year. Even among patients who had experienced a given complication, only 20% of patients recalled it as a potential risk. Patients and surgeons also rated the severity of each complication on a 0 (mild) to 10 (severe) scale. Somewhat surprisingly, patients rated blood loss requiring a transfusion as the most severe complication (median score 6/10), with new motor weakness (5/10), death (4.5/10), and blindness (3/10) receiving less severe scores. Surgeons rated new weakness, re-operation, blindness, and death as significantly more severe than patients did.

 

This paper is consistent with prior studies showing poor patient recall of medical information relayed to them by a physician. While poor understanding of medical information is always a problem, the potential downside is quite high in ASD surgery, where failure to understand the potential for serious complications puts patients at risk for dissatisfaction and surgeons at risk for litigation. The poor recall of potential complications, even of those experienced by the patient, is quite concerning. The most surprising and novel finding was the incongruity between patient and surgeon ratings of complication severity. Patients rating blood loss requiring a transfusion as more severe than new weakness, death, and blindness implies they either did not understand the task, did not understand the implications of the complication, or have a set of values significantly different from surgeons. Most readers would agree than rating transfusion as more severe than death does not make sense. These data should serve as the impetus to improve the consent process, which is clearly not producing the desired results. The authors noted this “enhanced” consent process included a video reinforcing the verbal consent discussion, but this process was clearly not effective. It is possible that better visuals in the video demonstrating the planned surgery as well as illustrating the potential complications and how they affect patient quality of life would lead to better retention of information. Patient testimonials from those who had experienced specific complications might create a more powerful impression. While the current consent document may provide a modicum of legal protection, the true goal of the process is to create an informed patient who understands the potential risks and outcomes from surgery. Hopefully future studies will work to advance and refine the entire consent process.

 

Please read Dr. Saigal’s article on this topic in the July 15 issue. Does this cause you to change how you view the surgical consent process? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor


Thursday, July 09, 2015

Much has been written about the advantages and risks associated with anterior and posterior surgery for multilevel cervical degenerative disease. Conventional wisdom suggests that anterior surgery is generally favored for one or two level pathology due to low rates of pseudarthrosis and dysphagia, while posterior surgery is favored for four or more level surgery due to unacceptably high rates of pseudarthrosis associated with stand-alone anterior procedures. Debate about the best approach for three level disease persists, and specific patient characteristics such as preservation of lordosis, location of neural element compression, and body habitus all play into surgical decision-making. Given the lack of consensus about the best surgical approach for multilevel cervical degenerative disease, a group of researchers at Stanford University undertook a propensity-score matched  analysis of the MarketScan database from 2006-2010 to compare complications, length of stay, 30 day readmission rate, reoperation rate, and costs between patients undergoing anterior and posterior surgery for cervical degenerative disease requiring instrumentation of at least three levels. Patients undergoing foraminotomy, laminectomy, or laminoplasty without fusion were excluded, as were patients undergoing AP procedures. How the authors defined “three levels” is somewhat vague, as their code for anterior instrumentation implies at least 3 disk levels were fused, while their code for posterior instrumentation suggests at least 3 vertebral levels (i.e. 2 disk levels) were included. They reported that anterior surgery patients had higher rates of dysphagia (6.4% vs. 1.4%) but lower or similar rates of essentially all other complications. The posterior surgery patients had markedly higher rates of infection (3.2% vs. 0.9%) and wound dehiscience (1.3% vs. 0.1%). The posterior group also underwent readmission at twice the rate of the anterior group (10% vs. 5%) and reoperation at a 50% higher rate (18% vs. 12% over an average of less than 2 years of follow-up). The posterior group also had a length of stay 1.5 nights longer and hospital costs about $5,000 more than the anterior cohort.

 

This study addresses an important clinical question from the typical 30,000 foot viewpoint provided by large administrative database studies. Their findings support prior literature indicating higher rates of dysphagia for anterior patients with higher rates of wound complications for posterior patients. Prior to condemning posterior surgery, the significant limitations of this study design must be considered. A major limitation is that failure of the authors to determine the number of levels fused for each patient. This information should be available from CPT coding, so it is unclear why it was left out. It seems likely that the posterior group includes more patients undergoing four or more level fusions, while that anterior group is likely primarily made up of three level cases. Additionally, the underlying diagnosis is unknown, and the posterior surgery group may include more myelopathy patients who are at greater risk of complications compared to radiculopathy patients. The authors did not control for comorbidity burden, which may have been greater in the posterior group. They also were unable to determine the cause of reoperation, which would have been important to know (i.e. infection, adjacent segment degeneration, pseudarthrosis, etc.). The final missing piece from a database study on this topic is patient reported outcomes, arguably to most important outcome in evaluating a surgical technique. While database studies all have substantial limitations, this study supports current practice in which anterior surgery is favored for one and two level surgery, four or more level disease should be treated with a posterior or AP approach, and the approach for three level surgery remains dependent on patient characteristics and surgeon preference.

 

Please read Mr. Cole’s article on this topic in the July 1 issue. Does this change how you consider approaching multilevel cervical disease? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor


Friday, July 03, 2015

There is mounting laboratory and clinical data suggesting that early decompression and stabilization of fractures associated with spinal cord injuries (SCI) leads to better long-term neurological outcomes. The STASCIS observational cohort study found better neurological outcomes in patients undergoing surgery within 24 hours, though there were significant baseline differences between the early and late surgery groups.1 Despite recommendations for early surgery in SCI patients, surgery is frequently delayed for a variety of reasons including other life-threatening injuries precluding urgent spinal surgery, medical comorbidities necessitating further investigation and treatment, the need for advanced imaging, patient transfer to a tertiary care center, and the lack of OR availability. No recent, large-scale study has been performed to evaluate the timing of surgery in SCI patients, so the orthopaedic research group at Yale elected to analyze the National Trauma Data Bank to determine the timing of surgery in complete, incomplete, and central cervical SCI patients. They identified over 2,500 cervical SCI patients admitted in 2011 and 2012 and calculated the elapsed time from dispatch of EMS until surgery. They found that approximately 50% of complete and incomplete SCI patients were taken to the OR within 24 hours, with the remaining 50% undergoing surgery beyond 24 hours. Only 29% of patients with central cord injury were taken to the OR within 24 hours, a finding consistent with the lack of clinical evidence that early surgery leads to better outcomes in these patients. Not surprisingly, they found that patients with a higher medical comorbidity burden, those with upper cervical injuries, and those with head injuries had greater delays to surgery.

 

This study provides an interesting snapshot into the timing of surgery for cervical SCI in trauma centers across the United States. Given that 50% of complete and incomplete SCI patients underwent surgery within 24 hours, it suggests that surgeons are making an effort to get SCI patients to the OR urgently. On the other hand, it is somewhat concerning that surgery is delayed for greater than a day in half of these patients. While this study design provided a good description of the typical timing of surgery, it did not allow for much understanding about the reasons for delay. It comes as no surprise that more severely injured patients, those with more complex upper cervical injuries, and those with medical comorbidities experienced greater delays. The pressing question that remains unanswered is what causes preventable delays in getting to surgery. System issues such as slow transfers, delayed MRI, and limited OR availability are all potential targets for improvement if a study can demonstrate that these are barriers to early surgery. Surgeons may also play a role in delays to surgery if they are unavailable or choose to delay surgery for their own convenience. Unfortunately, this large-scale database study does not allow for a level of granularity that could answer these more practical questions. Other potential limitations of this study include those inherent to all database studies including potential miscoding of information such as type of SCI or inaccurate data about the timing of events. It is unclear if this database includes information on transfer between medical centers, and it seems as though this would be a driver of delayed surgery. There will never be a Level 1 trial demonstrating the superiority of early surgery for SCI, but the observational and basic science data that exist suggest it is beneficial. This study should serve as an impetus for hospitals and surgeons that care for SCI patients to make an effort to reduce system barriers to early surgery.

 

Please read Mr. Samuel’s article on this topic in the July 1 issue. Does this change how you approach efforts to get SCI patients to the OR urgently in your institution? Let us know by leaving a comment on The Spine Blog.


Adam Pearson, MD, MS

Associate Web Editor

 

 

REFERENCE

1.         Fehlings MG, Vaccaro A, Wilson JR, et al. Early versus delayed decompression for traumatic cervical spinal cord injury: results of the Surgical Timing in Acute Spinal Cord Injury Study (STASCIS). PLoS One 2012;7:e32037.

 

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.