Surgery Versus Nonsurgical Treatment of Lumbar Spinal Stenosis: A Randomized Trial

I found the article by Delitto, et. al. at odds with not only my experience, but that of other published studies. The way the data and results were reported in the Annals article leave more questions than answers.

These include:
- It is not stated if the 169 patients who were deemed eligible for surgery had gone through physical therapy (PT) first.
- If not, the 87 patients (of the 169) assigned to surgery had no PT which in an elective setting is a breech of the standard of care.
- If so, then the assumption can be made that all 169 had already failed PT.
- Of the 82 assigned to PT, only 29 finished the treatment with 15 improving. The authors say the 15 of 29 improved is a 52% success rate. A more accurate outcome of this group is 15 successes out of 82 originally in the group for an 18% success rate.
- The authors address this in the article stating that the high percentage of crossovers, or patients leaving the PT group for the surgery group "presents a challenge in interpretation." Indeed.
- It would have been useful to know why so many patients left the PT group.
- Although the actual number of patients completing PT is not stated, it appears from what is provided that the large majority of patients did not complete the proscribed PT arm of the study, leading the authors to state, "we did not see a relationship between attendance in PT and outcome, including the probability of success." That is to say, PT had no bearing on outcome in this group.
- The success in the surgery group was 61%. The text of the article states there were 33 surgical complications; the accompanying table lists 22. The text states that 11 were in the patients who crossed over from PT to surgery, of which there were 44. These 11 complications are not detailed. The complication rates for surgery in this study were very high, 22 of 74 patients who had surgery in the original surgery group, or 30%, and 11 of 44 in the cross over surgery group, or 25%. The combined surgical complication rate was 33/118 or 28%. This is higher than reported in other surgical series, and may be the explanation for the overall surgical success rate of 61% which is lower than in many other reported studies. This possibility is not addressed in the discussion section of the study.

For the reasons stated above, among others not included in this letter, the conclusions of the authors are highly suspect.

Dear Sir,

Re Delitto et al, Surgery versus nonsurgical treatment of lumbar spinal stenosis: a randomized trial.

We congratulate Delitto et al for conducting an RCT comparing surgery with physiotherapy (PT) for the treatment of lumbar spinal stenosis (LSS) but we have serious concerns regarding the methodology and in particular, with the authors’ interpretation of the results. We cannot agree that the study shows that “surgical decompression yielded similar effects to a PT regimen among patients with LSS who were surgical candidates.” We believe the adherence to intention-to-treat analysis (ITT) severely distorts the results leading to erroneous conclusions.

The study flow diagram indicates that almost two-thirds of suitable patients (312/481) declined to participate and be randomised. No information on these patients was presented but based on previous, larger, similar studies, these non-participants are likely to have experienced greater disability than those who volunteered to randomisation1, 2 bringing doubt to this study’s external validity.

Of the patients allocated to PT, 57% crossed-over to surgery after receiving on average 7.8 PT treatment sessions. In the ‘real world’ cross-over equates to treatment failure, yet the authors do not appear to acknowledge this when analysing PT treatment success. As treated, only 15/73 PT patients (21%) had a ‘successful’ outcome. Two patients crossed-over from surgery to PT, presumably crossing-over over before surgery took place. This delineates the near impossibility of performing an RCT between surgical and non-surgical care options – temporal inequality.

The value of ITT analysis in maintaining the benefits of randomization is clear when cross-over rates are low and study arms compare equivalent medical treatments. This methodology is inappropriate for surgical versus non-surgical treatments when cross-over is high in one arm of the study. Such trials tend to select a cohort of cases with mild severity of the study condition and suffer prolonged delays in recruitment, as did this trial.

In clinical practice, many patients have failed non-operative care, including PT, before considering surgery for a degenerative disorder such as LSS. As this study shows, some will get satisfactory improvement with PT. However, this study also shows that many with significant disability will opt out for surgical decompression. It is inappropriate to include these patients as PT ‘successes’. To suggest that the findings of this study demonstrate equivalence of PT and surgery represents a failure of the methodology of the study and its analysis. Comparison of surgical versus non-surgical therapies with high crossover remains a challenge for EBM methodology.



References:
1. Weinstein JN, Tosteson TD, Lurie JD, Tosteson A, Blood E, Herkowitz H, et al. Surgical versus nonoperative treatment for lumbar spinal stenosis four-year results of the Spine Patient Outcomes Research Trial. Spine. 2010 Jun 14;35(14):1329–1338.

2. Weinstein JN, Lurie JD, Tosteson TD, Tosteson ANA, Blood EA, Abdu WA, et al. Surgical versus nonoperative treatment for lumbar disc herniation: four-year results for the Spine Patient Outcomes Research Trial (SPORT). Spine. 2008 Nov 30;33(25):2789–2800.

Dear Sirs:

Delitto et al (1) reported on a randomized trial of surgical vs non-surgical treatment of symptomatic lumbar spinal stenosis (LSS). They (1) concluded that surgical decompression yielded similar effects to a physical therapy (PT) regimen among LSS surgical candidates. Authors recommended decision-making conversations between patients and healthcare providers (1), as previously stated (2).

Data to guide providers and patients in complex LSS judgements were not specified (1), and have not been conclusive (2, 3). Treatment of this condition was described as a balancing act needing an expansive research agenda (2). Randomized trials demonstrate average efficacy of therapy, not revealing different clinical subgroups within a broad spectrum of disease (4). Individual distinctions are crucial features of good patient care and concerns for what patients feel, think, or want (4).

The recent report (1) stated, “The surgical approach in these studies has been highly standardized,” but differences were reported in decisions on whether to perform a decompression, with our without fusion or instrumentation (5). Treatment decisions in LSS are further complicated by person’s medical and physical circumstances and expected quality of life outcomes. A chronic disease model may preferably be applied to LSS. Elements can include: 1) effective communications among professionals, including PT, primary or specialist medical providers, and consulting surgeons; 2) patient-focused education and services, and 3) coordination of cost-effective, timely, and evidence-based interventional managements or procedures. The complexity of LSS merits research on personalized management and outcome studies.

In a private context (ATM), the difficulty in decision making on first-diagnosed (December 2013), multi-level, bilateral, severe (MRI imaging), symptomatic LSS was experienced. Knowledgeable in spine biomechanics and clinical epidemiology (6), decompressive surgery was opted (03-10-2015). Preceding chronic lower extremities’ stiffness, tightness, and guarded gait were promptly relieved and office functions were resumed 3-weeks post-op. Home PT is permitting improvement of diminished lower extremities strength and coordination. Even if favorable personal assessment persists and could be completely objective, One swallow does not a summer make (Aristotle, 384 BCE - 322 BCE).

This letter calls for research in personalized management of patients in the multifaceted LSS spectrum, including: 1) validated central stenosis severity rating scales; 2) objective evaluations of individual’s physical functioning; 3) neurological status; 4) overall physical condition, and 5) person’s expected quality of life. Such systematic data tracking in the course of this chronic and progressive disorder could help attain more timely personalized decisions, shared by informed patients and designated providers.

References
1. Delitto A, Piva SR, Moore CG, Fritz JM, Wisniewski SR, Josbeno DA, Fye M, Welch WC. Surgery versus nonsurgical treatment of lumbar spinal stenosis: a randomized trial. Ann Intern Med. 2015 Apr 7;162(7):465-73. doi: 10.7326/M14-1420.

2. Deyo RA. Treatment of lumbar spinal stenosis: a balancing act. Spine J. 2010 Jul;10(7):625-7. doi: 10.1016/j.spinee.2010.05.006.

3. Weinstein JN, Tosteson TD, Lurie JD, Tosteson AN, Blood E, Hanscom B, et al SPORT investigators . Surgical versus nonsurgical therapy for lumbar spinal stenosis. N Engl J Med. 2008; 358:794-810.

4. Feinstein AR. Twentieth century paradigms that threaten both scientific and humane medicine in the twenty-first century. J Clin Epidemiol. 1996;49(6):615-7.

5. Irwin ZN, Hilibrand A, Gustavel M, McLain R, Shaffer W, Myers M, Glaser J, Hart RA. Variation in surgical decision making for degenerative spinal disorders. Part I: lumbar spine. Spine (Phila Pa 1976). 2005 Oct 1;30(19):2208-13.

6. Masi AT. Might axial myofascial properties and biomechanical mechanisms be relevant to ankylosing spondylitis and axial spondyloarthritis? Arthritis Res Ther. 2014;16(2):107. Epub 2014 Apr 8.

We agree with Dr. Barrer that conservative care should precede considering surgery. We disagree that not having prior physical therapy is a “breach of care,” however. Exactly what constitutes conservative care is not universally agreed upon. Physical therapy is one form of conservative care, as is watchful waiting, epidural steroids, drug regimens and any number of combinations. In our study, patients were deemed surgical candidates by surgeons in large part because they had failed conservative care, including in some instances previous physical therapy. With respect to high crossover rate, complier average causal effect (CACE) and inverse probability weighting (IPW) analyses were done to address that specific issue. In terms of success rates of surgery, it would be helpful if the Dr. Barrer had included references, as definitions of success can vary. We defined success as 0.5 standard deviation improvement regardless of crossover status because we believed the risk of surgery warranted setting a high bar. As for the implication that the surgical group did not fare well overall, the plot of the group means suggests otherwise and parallels very well the outcomes of the surgical groups in both the SPORT and Malmivaara trials. The text and table list 33 complications (22 surgery group and 11 PT group) that are clearly detailed in the table. Complications that were actually surveyed in other studies had similar rates as ours (e.g., reoperation was 8% in SPORTS and 6% in Malmivaara trials). (1, 2)
In response to Drs Robertson et al; we agree that generalizability of study results is limited to those patients who agree to a 50% chance to be randomized to physical therapy. In the vast majority of refusals, patients cited the strong desire to have surgery as the reason for refusal and it cannot be assumed that these results would generalize to that group. Understand the balancing act of internal versus external validity, with the sacrifice of generalizability in order to strengthen internal validity by reducing cross-over in at least one of the arms of the study. We disagree that the number of PT sessions is related to treatment failure. The most often cited reason for discontinuing physical therapy as the burden of co-payments. With regard to the 2 cross-overs from surgery to physical therapy, we would certainly agree that it is impossible to perform a perfect surgical versus non-surgical care. However, with such a minuscule cross-over rate in the surgical group, we believe the goal of reducing crossover in one group allowing for meaningful intention to treat analyses was achieved. We agree that crossovers in the physical therapy group presented a challenge in analyses, something we tried to address using CACE and IPW.
References


1. Weinstein JN, Tosteson TD, Lurie JD, Tosteson AN, Blood E, Hanscom B, et al. Surgical versus nonsurgical therapy for lumbar spinal stenosis. New England Journal of Medicine. 2008;358(8):794-810.
2. Malmivaara A, Slatis P, Heliovaara M, Sainio P, Kinnunen H, Kankare J, et al. Surgical or nonoperative treatment for lumbar spinal stenosis? A randomized controlled trial. Spine. 2007;32(1):1-8.

Symptomatic lumbar spinal stenosis represents the most common diagnosis for which lumbar spinal surgery is performed in the United States. The variation in the utilization of surgery for this condition underscores the importance of developing a better evidence base to support the development of standard treatment guidelines.1 The recently published RCT – “Surgery versus nonsurgical treatment of lumbar spinal stenosis: A randomized trial” by Delitto et al. (Ann Intern Med. 2015;162:465-473) - provides high quality data but misses the opportunity to clarify how these data might be used.
The authors intended to address whether surgery versus 6 weeks of physical therapy would have different treatment effects using the validated SF-36 physical function outcome at a 2-year endpoint. The major flaw in the trial is a 57% crossover from the physical therapy to the surgical arm, which precludes the ability to answer the original study question and limits the ability to draw meaningful conclusions from an intention to treat analysis. The authors used complier average causal effect and inverse probability weighted analyses to manage the confounding effects of high cross over. This is a reasonable approach and the authors concluded that the treatment effects in both arms were not different. Although supported by the analyses, this is a misleading conclusion. Given expected non adherence in these situations, a much larger trial would be required to compare patients treated with non-surgical care only to surgical care.2 The trial is effectively a surgery versus physical therapy with a possible delayed surgery trial. The distinction is important for patients, physicians, and payers.
Few would debate the role of additional physical therapy for patients with stenosis who are surgical candidates. However, to state that surgery is equivalent to 6 weeks of physical therapy is simply an incorrect assessment of the data. The authors do not report an as treated analysis as the SPORT investigators did when they presented results of their RCT, which had crossovers of 43% from nonsurgical to surgical therapy and 33% from surgery to nonsurgical treatment. Using an as treated analysis, they demonstrated a significant benefit associated with surgery versus nonsurgical management.3
Looking at the 82 patients in the physical therapy arm, 56 (68%) ultimately underwent surgery and 13 were lost to follow-up or unable to participate, leaving only 13 patients with follow-up in this arm. Therefore, it is imperative for accurate interpretation of these data for spinal surgeons and patients alike to have access to baseline characteristics of the crossover patients as well as an as treated analysis of the data. This approach might help surgeons to determine when in the natural history of symptomatic lumbar stenosis to recommend surgical intervention or not. Furthermore, it would be important to know whether compliance with 6 weeks of physical therapy was associated with a reduction in the crossover rate.
Two major challenges in the clinical management of lumbar spinal stenosis are that radiographic features do not necessarily correspond with clinical symptoms and the natural history waxes and wanes over time in many patients. This trial does not provide high level evidence on the effectiveness of surgery or not. It does point out that we need to focus more clinical trial development on questions that can be answered in a way that will elevate clinical practice.
Sincerely,

Zoher Ghogawala MD
James D. Dziura PhD
John K. Ratliff MD
Praveen V. Mummaneni MD

On behalf of the American Association of Neurological Surgeons – Congress of Neurological Surgeons Joint Section on Disorders of the Spine and Peripheral Nerves

1. Weinstein JN, Lurie JD, Olson PR, Bronner KK, Fisher ES. United States' trends and regional variations in lumbar spine surgery: 1992-2003. Spine 2006; 31(23): 2707-14.
2. McCormick PC. The Spine Patient Outcomes Research Trial results for lumbar disc herniation: a critical review. Journal of neurosurgery Spine 2007; 6(6): 513-20.
3. Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical versus nonsurgical therapy for lumbar spinal stenosis. The New England journal of medicine 2008; 358(8): 794-810.