Socioeconomics in Spine Surgery

Keywords: cost-effectiveness, comparative effectiveness research, cost/QALY, randomized controlled trials, evidence-based medicine, conflict of interest, , , ,

11.1 Introduction

In the last two decades, the expense of surgical spine care has risen dramatically, and at a higher rate than other inpatient procedures. ¹ The number of lumbar fusions increased 2.7-fold between 1998 and 2008. The overall national spending for spinal fusion increased from $4.3 billion to $33.9 billion in this period. This trend has not abated in the 7 years since, and does not translate into improved health status. The fact that, nationally, surgical spine care costs are rising at a pace greater than that of overall surgical health care expenditure suggests unique economic features within this subspecialty.

Economic “stakeholders” have assumed a greater scrutiny of the medical decision processes. Cost-effectiveness (CE) analysis has established methods used in comparative effectiveness research (CER). CER has been defined by the Institute of Medicine as “… the generation and synthesis of evidence that compares the benefits and harms of alternative methods to prevent, diagnose, treat and monitor a clinical condition or to improve the delivery of care. The purpose of CER is to assist consumers, clinicians, purchasers, and policy makers to make informed decisions that will improve health care at both the individual and population levels.” ²

CER has developed equations for using outcome-based investigational studies in establishing relative interventional value (see next section). Evidenced-based medicine (EBM), therefore, has assumed a greater relevance in times of unsustainable increases in health care expenditures. Investigational studies have always been a part of valid scientific inquiry and method to inform the practicing medical clinician, the emphasis being on establishing improved methods of care and ruling out potentially harmful ones. The introduction of value measurement has qualified the clinician’s use of investigational results by imposing an economic rationale in interventional decision-making.

Establishing valid investigational outcome comparisons in the interventional care of the painful degenerative lumbar spine (PDLS) is extremely challenging (see below). This difficulty has been in part the consequence of inherent clinical factors: the extreme diversity of individual pathology, the variance of medical status of study subjects rendering poor control of potential response factors, and the subjective nature of these outcome responses. Besides problematic issues in outcome measurement, investigational design may have poor control over standardization of the intervention studied. A multicenter study, for example, may involve surgeons with differing educations, training, experience, and technical capability.

11.2 Cost/Quality-Adjusted Life Years: Metric of Relative interventional Value

Value is defined as directly proportional to quality and inversely so to cost. The standard economic formula is therefore V = Q/C. If quality is established as a measurable entity, then cost effectiveness (CE) may be defined as the inverse of the value equation: CE = cost/measured quality.

Quality is established by outcome measurement. Presently, various types of health-related quality of life (HRQL) measures are used in spine care evaluation. Patient-centered measures are preferable in value establishment, and include the following:

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  Disease-specific measures, e.g., Oswestry Disability Index (ODI) and Neck Disability Index.

  
  
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  General health-related outcome measures, e.g., SF-36 (36-Item Short Form Survey) and derivatives/versions (SF-12, SF-8, SF-6D).

  
  
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  Utility measures ³ are based on economic and decision theory requiring patient to establish a subjective point of indifference between two health conditions, e.g., Euroqol EQ-5D, Health Utility Index, SF-6D (derived from SF-36 and SF-12)

Concept of “QALY” (quality adjusted life years): a calculated measure that incorporates a time-length factor for an established outcome-based quality measurement. Utility outcome measures are used in QALY computation, though there is a conversion formula relating ODI to SF-6D and thus making ODI usable in QALY calculation.

Cost measurement is complicated and without a standard method of calculation. Both “direct” and “indirect” costs are included.

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  Direct costs: those attributable to actual patient care. Complexity of calculation secondary to lack of “price” transparency and their variances, and the reliance on patient recall.

  
  
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  Indirect costs: those attributable to lack of productivity. Calculation with time factor is not standardized and often requires patient-reported data.

Cost/QALY: a standard monetary value metric of an intervention as established by outcome-based quality assessment with limitations of calculation complexity, nonuniformity, and patient recall in data collection.

11.3 Evidence-based Medicine

11.3.1 Defined

The other major initiative in the control of health care costs, one mainly directed by medical professionals, is the thrust toward establishing establishing evidence-based medicine (EBM). EBM has become the catch phrase for evaluating the relationship between clinical application and scientific validity. It has been defined as “… the use of mathematical estimates of the risk of benefit and harm, derived from high-quality research on population samples, to inform the clinical decision-making in the diagnosis, investigation or management of individual patients.” ^{4,​ 5} As noted earlier, this definition could be expanded, since EBM outcome data inform economic as well as clinical decision-making.

There are several forms of primary studies, all of which can have EBM validity in various situations. Cohort studies require long-term follow-up (sometimes decades) when two groups have had different exposures to a health-altering agent (including a defined surgical procedure). Case control studies usually address rare conditions and involve retrospective investigation of diseased and control groups in order to establish potential etiological factors. Cross-sectional surveys are often run by epidemiologists who collect specific data (related to medical care) from a representative sample at a single time point. Case reports and case series are generally considered as relatively weak as scientific evidence, but there are “…good theoretical grounds for the reinstatement of the humble case report as a useful and valid contribution to medical science, not the least because the story is one of the best vehicles for making sense of a complex clinical situation.” ⁶

11.4 Randomized Controlled Trials: Limitations for the PDLS Surgeon

Randomized controlled trials (RCTs) are the gold standard for investigational studies establishing therapeutic guidance. They are considered at the pinnacle of the hierarchy of medical evidence informing clinical decision-making. However, the statistical significance of an RCT may be “fragile,” meaning a small number of outcome events can eliminate significance. ⁷ And not all RCTs are “high-quality research”; some are patently invalid.

RCTs present averaged (“population”) data that are often of marginal benefit in the examining room, wherein the PDLS surgeon is interacting with the individual patient presenting with a pain complaint (which may or may not be of spinal etiology). The value of RCTs in degenerative spine surgery is further limited by nonuniform application of the investigated therapy, by large variability in comorbid substrate, and by subjectivity of outcome reporting. The swallowing of a pill is essentially the same by all subjects in a drug trial. On the other hand, lumbar fusion as a therapeutic measure will have a multitude of variances that can affect the individualized result: specificity of indication, procedural type and technique, experience of surgeon, patient comorbidities and psychosocial state, in-hospital and postoperative care, etc. And in a drug trial, the outcome data are usually reported as a distinct, objective, and measurable quantity. Fusion surgery outcome measurement, conversely, may have one or more of many different forms (functional, quality of life, pain scales), all of which are more qualitative and subjective.

Statistically, higher investigational numbers provide greater interpretive accuracy in measurement of therapeutic outcome. Hence, the results of systematic reviews of RCTs with meta-analysis of data can have greater practical relevance for the degenerative spine surgeon. However, the individual RCTs incorporated in these reviews have great heterogeneity in study design. And these RCTs can have limited application due to exclusion criteria, inclusion bias, disregard of qualitative aspects, publication bias, conflict-of-interest (COI) effects, inappropriate statistical evaluation, and accuracy. ^{8,​ 9} Many of these deficiencies are unavoidably transmitted to these large database studies and their incorporation will cause distortion of conclusions. Furthermore, clinical significance and statistical significance are not necessarily the same. ¹⁰

Thus for the degenerative spine surgeon, literature review often provides confusing guidance, if any at all, for the treatment of the individual patient with a pain complaint referable to the degenerative spine. In a systemic review, the surgeon may encounter an averaged conclusion that may or may not support a particular therapeutic effort. This surgeon will also likely discover that investigational results data will present some very positive individual outcomes and some poor ones. Such a spectrum of outcome is consequent to a fundamental complexity of evaluation and surgical decision-making in surgery for the PDLS. The degree of this complexity has a direct relationship to the extent of positive and negative outliers.

As a conceptual example, the efficacy of lumbar fusion for axial back pain may be investigated, versus nonoperative treatment as in the clinical study by Mannion et al. ¹¹ Such a reported systematic review of the literature may have no supportive evidence, or only weak evidence, for such surgery. And yet there will be certain individual cases of undeniable and dramatic success within the results data. The surgeon will note that the systemic review addressed surgical therapeutic outcome as measured in subjects with “chronic low back pain” (CLBP). There was no subclassification of this amorphous symptom according to its cause of onset, its course, its precise location/radiation, its relation to activity, etc. Thus, the conclusion of the systemic review was based on an averaged surgical therapeutic response for a nonspecific symptomatic entity. Any potential benefit of fusion for a more specifically defined subform of chronic back pain is obscured within the systemic review.

Should a study or studies report fusion results with more target specificity, there may be a different conclusion as to the efficacy of surgical fusion therapy. If, for instance, the “CLBP” studied was precisely subdefined as lumbar axial (centered midline), as specific to activity causation (antigravity elevation), and was coexistent with particular radiographic abnormality (marked interspace changes predominant at one level), then lumbar fusion for this subset of patients with “CLBP” may be validated as EBM.

In the earlier example, the genesis of the concept of a possible relationship between efficacy of lumbar fusion and a more specific subdefinition of “CLBP” can emerge only from clinical experience. The practicing physician/surgeon that is involved in the evaluation and treatment of degenerative spine pain provides the conceptual substrate for investigational studies. Thus, better care of patients with PDLS, surgical or nonsurgical, is primarily engendered by an interactive symptom-focused experience between the clinician and the individual patient.

11.5 Conclusion

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  Surgical spine care costs are increasing in an unsustainable manner and various “stakeholders” initiatives have developed accordingly.

  
  
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  Economic “stakeholders” have established the methods of CER, which uses economic mathematical tools to measure the relative monetary value in health care interventions.

  
  
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  Cost/QALY is a standard metric of relative interventional value and uses utility investigational outcomes in quality assessment.

  
  
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  Medical professionals have concentrated on the concept of EBM to measure clinical value in health care interventions by investigational literature evaluation.

EBM conclusion is dependent on the quality of studies investigated.

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  RCTs and their systemic reviews (with meta-analysis of their data) are considered at the top of the hierarchy informing clinical decision-making. Thus, EBM uses these studies as the predominant form for investigational evaluation though other types of investigational literature may have considerable value, including case reports.

  
  
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  RCTs can have definitive or nondefinitive results as defined by whether or not confidence intervals overlap the threshold of clinically significant effect. ⁶

  
  
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  The complexities in the surgical care of the PDLS often limit the clinical application of EBM because of averaging of group data. And EBM has practical, philosophical, and ethical limitations. ^{12,​ 13}

11.5.1 Potential Detrimental Effects of EBM

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  Undermines therapeutic management strategy at the individualized patient level. ¹⁴

  
  
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  Is a value given undue importance relative to professional experience. ¹⁵

  
  
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  Is used as a clinical directive based on evaluation of studies of poor quality, by design, method, and/or statistical evaluation.

  
  
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  Is a clinical directive corrupted by COI within the studies investigated or by the review EBM author(s) (see next section).

  
  
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  Results in a conclusion that obscures the need for population subset investigation.

  
  
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  Is used by health care purse holders to deny coverage for positive outlier individuals.

Symptom-focused clinical care provides the conceptual basis for investigative initiatives into interventional therapeutic effectiveness with special applicability in surgery on the PDLS.

11.6 Economics and Ethics in Spine Surgery: The Perfect Storm

Related posts:

Surgical Situations of Complex Decision-Making Postoperative Care Clinical Evaluation of the Patient with a PDLS Stabilization in SFC Surgery on the PDLS Fundamental Anatomy The Fundamental Open Surgical Method

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