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Friday, July 22, 2016

Adjacent segment disease (ASD) following spinal fusion is a well-described and much studied phenomenon.1 Efforts to mitigate the problem with total disk arthroplasty have not been very successful, with lumbar disk replacement falling out of favor and cervical disk replacement having mixed results in terms of reducing ASD. While ASD is known to develop at rates of 2-4% per year, risk factors for its development have not been clearly defined. As such, Dr. Mroz and his colleagues elected to retrospectively review 137 lumbar fusion patients in order to determine risk factors for developing ASD. They identified thirteen patients (9%) who underwent a revision surgery at an adjacent level (ASD group), with a mean duration to reoperation of 21 months. The 124 patients who did not develop ASD (non-ASD group) had a mean follow-up of 14 months. They performed both univariate and multivariate analysis in order to identify patient characteristics and surgical factors that affected the rate of ASD. The multivariate analysis revealed that antidepressant use (OR=5.4), degenerative scoliosis (OR=34.2), and undergoing L4-S1 fusion (OR=56.5) were all independent risk factors for developing ASD, while an increased sacral slope was protective. Previous studies had identified a decompression cranial to the fusion as a risk factor for ASD,2 but in the current study, none of the 13 ASD had a decompression above the fusion. Another study also suggested that a complete laminectomy at the cranial vertebra of the fusion also increased the risk of ASD,3 but that was not found to be a risk factor in the current study.

 

The authors have identified an interesting group of risk factors for the development of ASD following lumbar fusion. These factors include patient, disease, and surgical characteristics. While the paper represents a good effort to answer an important question—are there modifiable risk factors that predispose patients to developing ASD?—it has significant limitations that must be considered when interpreting the results. The major limitation was the small sample size and relatively short follow-up. While 137 patients were included, this is not sufficient to study an outcome that occurs at a rate of 4% per year if only 2 years of follow-up are available. Despite the fact that only 13 patients were in the ASD group, the authors did identify a few factors that were significant predictors of ASD. It comes as no surprise that degenerative scoliosis patients are at risk given that surgeons will frequently not include the entire curve in the fusion, which puts the adjacent, scoliotic levels at risk. Depressed patients frequently have less ability to cope with pain and may be more likely to seek surgical treatment for ASD. Having an L4-S1 fusion coverts L3-L4 to the most caudal lumbar motion segment, and this level seems particularly susceptible to ASD. While most of these factors are not modifiable, understanding how they play a role in ASD could affect how surgeons select their surgical procedures or counsel patients. Before drawing any strong conclusions that change practice, a larger study is needed with a higher number of ASD patients. Such a study would provide more power to evaluate the potential risk factors and yield much tighter confidence intervals around the odds ratios.

Please read Dr. Mroz's article on this topic in the July 15 issue. Does this change how you view ASD? Let us know by leaving a comment on The Spine Blog.

 

Adam Pearson, MD, MS

Associate Web Editor

 

REFERENCES

1.            Hilibrand AS, Carlson GD, Palumbo MA, Jones PK, Bohlman HH. Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. The Journal of bone and joint surgery American volume 1999;81:519-28.

2.            Radcliff KE, Kepler CK, Jakoi A, et al. Adjacent segment disease in the lumbar spine following different treatment interventions. Spine J 2013;13:1339-49.

3.            Ekman P, Moller H, Shalabi A, Yu YX, Hedlund R. A prospective randomised study on the long-term effect of lumbar fusion on adjacent disc degeneration. Eur Spine J 2009;18:1175-86.

 

 


Friday, July 15, 2016

Cervical fusion for degenerative disk disease (DDD) and axial neck pain remains controversial. While some observational studies have suggested reasonably good outcomes with cervical fusion for this indication, others have reported high rate of persistent neck pain. There is scant literature comparing outcomes between DDD and radiculopathy patients following cervical fusion. To address this, Dr. Faour and colleagues from Case Western performed a retrospective cohort study using the Ohio worker's compensation (WC) database to compare return to work (RTW) rates between DDD and radiculopathy patients who underwent a cervical fusion following a work-related injury. They identified 2,208 patients in the database who had undergone a single level cervical fusion between 1993 and 2011 and carried a diagnosis of either DDD or radiculopathy. A large majority (n=1,927) had a diagnosis of radiculopathy, while the remaining 281 were classified as DDD. Over 99% underwent an anterior fusion, with a handful undergoing a posterior or AP fusion. The DDD patients were about 3 years older, more likely to have a psychiatric diagnosis, be on narcotic pain medication, be on permanent disability or to be out of work for over 6 months prior to surgery. The authors found that significantly more radiculopathy patients returned to work for at least a 6 month stint over the 3 years following surgery compared to the DDD patients (63% vs. 51%). Even after controlling for potential confounders (i.e. psychiatric diagnosis, narcotic use, etc.), DDD as a diagnosis remained a strong independent predictor of not returning to work (OR=0.61).They reported similar findings for RTW at 1 year. There were no differences in complications between the two diagnostic groups.

The authors should be congratulated for performing a high quality database study that provides some of the only data comparing outcomes between cervical DDD and radiculopathy patients undergoing cervical fusion. While the DDD group was much smaller than the radiculopathy group, the differences in RTW were very statistically significant, even after controlling for important confounders. This study confirms what most spine surgeons have suspected on this topic, namely that DDD patients who undergo cervical fusion do not do as well as radiculopathy patients. The major limitation was that the study did not report patient reported outcomes. However, RTW is a complex variable that is typically not sensitive for detecting differences in outcomes (i.e. in the SPORT disk herniation study, there were no differences in RTW between the surgery and non-operative groups despite markedly better patient reported outcomes in the surgery group1), so differences in RTW rate likely reflect a meaningful difference in the patients' outcomes. Depending on ICD-9 codes for classifying the indication for surgery is potentially problematic, however, if the misdiagnosis was random, this would obscure rather than amplify differences. The overall 3 year RTW rate of 60% following cervical fusion is not stellar, and patients need to understand they may not be able to RTW even after a technically successful surgery. Cervical DDD remains a questionable indication for fusion, particularly among the WC population. Future prospective studies should compare patient reported outcomes between cervical DDD and radiculopathy patients following fusion.

Please read Dr. Faour's article on this topic in the July 15 issue. Does this change how you view cervical DDD as an indication for fusion? Let us know by leaving a comment on The Spine Blog.


Adam Pearson, MD, MS

Associate Web Editor

 

REFERENCE

1.            Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical versus nonoperative treatment for lumbar disc herniation: four-year results for the Spine Patient Outcomes Research Trial (SPORT). Spine 2008;33:2789-800.

 

 


Friday, July 8, 2016

Increasing the value of care is a high priority in healthcare systems across the world. This can be accomplished by improving quality or decreasing costs while holding the other variable constant. In many situations, decreasing cost while maintaining quality is the easier route to increasing value. Much has been written about cost variation at the institution or regional level, with less literature focusing on physician level data. In spine surgery, many decisions that affect cost are made at the surgeon level, so using the surgeon as the unit of analysis is important to understanding and ultimately changing behavior that drives cost. Dr. McGuire and colleagues from Boston performed a cost analysis looking at variation among seven surgeons for ACDF, lumbar discectomy, lumbar laminectomy, and posterior lumbar fusions. Only one and two level elective procedures were included. They categorized costs as those associated with inpatient stay, operating room, supplies/instrumentation, anesthesia, or others. They performed unadjusted analyses looking at costs at the individual procedure level and also reported results from an analysis adjusted for patient and procedure characteristics across all four procedures. In the unadjusted analyses, costs varied among surgeons between 30% and 40% for ACDF, lumbar discectomy, and lumbar laminectomy. Greater variation was observed for posterior lumbar fusion, where costs varied over 80% ($12,000 for the least costly surgeon to $22,000 for the most costly). The adjusted analyses showed approximately 30% variation among the surgeons when all four procedures were combined. The mean procedure cost was $8,800, with the least costly surgeon accruing costs $1,400 less than the mean and the most costly $800 above the mean. Not surprisingly, instrumentation made up the majority of the cost for the fusion procedures. Inpatient stay and OR costs were the major contributors to the cost of the non-fusion procedures. The cause of variation differed across surgeons though tended to be related to either instrumentation or OR costs.

This study represents a novel approach to looking at spine surgery costs at the individual surgeon level. Given that most cost decisions are made at this level, it is a natural place to look to find targets for cost reduction due to unnecessary variation. The modest level of inter-surgeon variation was actually somewhat surprising given the much greater levels of variation reported in prior studies.1 This low level of variation may reflect previous standardization efforts at this institution, to which the authors alluded. While this paper looks at cost at a relatively detailed level, even more specific data like what goes into "OR costs" would be helpful. One can assume this is driven by time spent in the OR, but it would have been helpful to have this explained in greater detail. The greatest driver of cost variation seems to have been lumbar instrumentation. The authors could have performed an even more detailed analysis to determine if this was being driven by variation across implant manufacturers or across type of instrumentation the surgeon elected to use (i.e. interbody devices, percutaneous vs. open pedicle screws, etc.) The most modifiable factors that affect cost are likely instrumentation and inpatient stay. Instrumentation costs can be reduced by going to a single vendor or having the institution set price caps for different implants. Inpatient stay costs can be addressed by performing procedures like lumbar discectomy and single level laminectomy as outpatient procedures. The authors (and surgeons included in the study) should be applauded for being willing to look at cost at the surgeon level. We look forward to a follow-up study that reports on how these data was used to change specific behavior and reduce unnecessary variation in cost.

Please read Dr. McGuire's paper in the July 1 issue. Does this change how you think about how individual surgeons can reduce the cost of spine surgery? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor

REFERENCE

1.            Epstein NE, Schwall G, Reillly T, Insinna T, Bahnken A, Hood DC. Surgeon choices, and the choice of surgeons, affect total hospital charges for single-level anterior cervical surgery. Spine (Phila Pa 1976) 2011;36:905-9.


Saturday, July 2, 2016

Patients frequently ask spine surgeons about their likelihood of returning to work after undergoing a cervical or lumbar fusion, and surgeons frequently answer based on their anecdotal experience. Given that this is such an important topic to many patients, it would be nice to have firm data with which to answer the question. Dr. Bohl and his colleagues from Chicago retrospectively reviewed post-operative functional capacity examination (FCE) findings for 71 minimally invasive TLIF and 102 ACDF patients who had filed worker's compensation claims. They stratified patients according to pre-operative work demand (sedentary/light, medium, or heavy/very heavy) and then classified their outcome according to their post-operative work capacity according to their FCE after being declared at maximum medical improvement. Among TLIF patients, only 37% met their preoperative work requirements, compared to 54% of ACDF patients. Not surprisingly, the strongest predictor of meeting preoperative work requirements was the preoperative work demand. While 78% of TLIF patients and 92% of ACDF patients who had sedentary or light job requirements returned to at least this level of function post-operatively, only 26% of TLIF and 27% of ACDF patients with heavy or very heavy job requirements returned to this level of function. In multivariate analysis, age also predicted returning to one's preoperative work capacity for ACDF patients (younger patients were more likely to attain their preoperative work status), while no other factors were predictive for TLIF patients.

 

The author should be applauded for providing firm numbers to answer a frequently encountered clinical question. Their straightforward analysis now allows surgeons to have frank discussions with injured workers pre-operatively about their likely post-operative work capacity. It is important for patients with heavy work demands to understand that there is only about a 25% chance of them returning to that level of function following either a lumbar or cervical fusion. Conversely, patients with light work demands should be optimistic about being able to return to their previous level of work following surgery. Return to work after surgery is a highly complex outcome, with patient, employer, biomedical, and socioeconomic factors all affecting it. It was the essentially the only outcome in the Spine Patient Outcome Research Trial disc herniation study with no differences between the surgical and non-operative patients.1 Given the complex nature of returning to work, patients need to understand that they can have an excellent surgical result yet still not be able to return to their pre-injury work capacity. Workers with heavy work demands, especially those who are older, undergoing a lumbar fusion, or who have been out of work for an extended period of time, need to understand that they are unlikely to return to the same type of job. Setting appropriate expectations pre-operatively will lead to greater post-operative patient satisfaction and may also allow for an earlier transition to vocational rehabilitation. While the results of this paper represent the experience of a single surgeon in a single city, they do provide spine surgeons with firm numbers that can be conveyed to worker's compensation patients during a shared decision-making discussion.

 

Please read Dr. Bohl's article on this topic in the July 1 issue. Does this change how you will counsel fusion patients about their likely post-operative work capacity? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor

 

REFERENCE

1.            Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical versus nonoperative treatment for lumbar disc herniation: four-year results for the Spine Patient Outcomes Research Trial (SPORT). Spine 2008;33:2789-800.

 


Friday, June 24, 2016

The current opioid epidemic has raised awareness about the negative consequences of long-term narcotic use. Many patients who become opioid addicts were first exposed to narcotics following surgery or an injury. While opioids will likely continue to have an important role in post-operative pain control, ways to minimize their use need to be considered. The short-term negative effects of narcotics are also problematic for spine surgeons and their patients. With efforts to move spine surgery to the outpatient setting and minimize the length of inpatient stays, side-effects such as nausea, vomiting, ileus, and delirium all present impediments to rapid discharge. As such, interest in multimodal analgesia (MMA) has increased. This approach seeks to capitalize on the synergistic effect of different classes of pain medications, including local anesthetics, neuromodulators, muscle relaxants, anti-inflammatories, acetaminophen, and narcotics. MMA allows for the dose of each medication to be minimized, thus reducing side effects. It has been shown to be effective in total joint arthroplasty and lumbar surgery, though it may have an even larger role in outpatient or short stay procedures. As such, Dr. Bohl and his colleagues from Rush University Medical Center in Chicago recently published their experience with MMA for ACDF. While they initially attempted to perform an RCT, poor protocol adherence resulted in them deciding to abandon the RCT and perform an observational cohort study. They enrolled 239 patients undergoing ACDF by a single surgeon over a 5 year period. Patients were allowed to select their analgesia approach, with 23% selecting MMA and 77% choosing patient-controlled analgesia (PCA). Both protocols were similar and included pre-operative oxycodone, pregabalin, IV acetaminophen, and a local anesthetic injection. The main difference was that the PCA group received a morphine PCA pump on post-op day 0 along with IV fentanyl prn, while the MMA group received tramadol, hydrocodone, and pregabalin on post-op day 0. Starting on post-op day 1, all patients received hydrocodone and cyclobenzaprine. Since this was not a randomized study, the groups were somewhat different, with the PCA group having significantly more comorbidities and a higher rate of smokers. The MMA group used significantly fewer oral morphine equivalents per hour while in the hospital (2.5 mg/hr vs. 5.8 mg/hr), had less nausea/vomiting (6% vs. 38%), and a shorter length of stay (27 hrs vs. 40 hrs). There were no differences in visual analog pain scores in the hospital or the rate of narcotic use at 6 or 12 weeks.

 

The authors have done a nice job reporting their experience with MMA for ACDF, an outpatient or short-stay procedure at most institutions. They demonstrated a 30% reduction in the length of stay, which may have been due to reducing the negative side effects associated with PCA use. While these results are promising, the reader must remember that this was not a randomized trial and that there were significant baseline differences between the groups that may have been driving the differences. The PCA group had more medical comorbidities and a higher number of smokers, which may have resulted in some of the observed differences (though some prior studies have shown a shorter length of stay for smokers, who want to leave the hospital to smoke). The other interesting result was that over three quarters of patients chose the PCA over MMA. Studies such as this one can be used as evidence to educate patients about the negative short-term effects of narcotics and possibly change their expectation to receive a PCA pump following surgery. As more spine surgery transitions to outpatient or short-stay procedures, the importance of effective analgesia without the side-effects associated with high dose narcotics becomes more important. Hopefully future studies on MMA will employ randomized designs in order to definitively evaluate the benefits of different analgesic regimens.

Please read Dr. Bohl's article on this topic in the June 15 issue. Does this change your approach to peri-operative analgesia? 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.