Thomas D. Cha

A proposed set of metrics for standardized outcome reporting in the management of low back pain

Background and purpose — Outcome measurement has been shown to improve performance in several fields of healthcare. This understanding has driven a growing interest in value-based healthcare, where value is defined as outcomes achieved per money spent. While low back pain (LBP) constitutes an enormous burden of disease, no universal set of metrics has yet been accepted to measure and compare outcomes. Here, we aim to define such a set. Patients and methods — An international group of 22 specialists in several disciplines of spine care was assembled to review literature and select LBP outcome metrics through a 6-round modified Delphi process. The scope of the outcome set was degenerative lumbar conditions. Results — Patient-reported metrics include numerical pain scales, lumbar-related function using the Oswestry disability index, health-related quality of life using the EQ-5D-3L questionnaire, and questions assessing work status and analgesic use. Specific common and serious complications are included. Recommended follow-up intervals include 6, 12, and 24 months after initiating treatment, with optional follow-up at 3 months and 5 years. Metrics for risk stratification are selected based on pre-existing tools. Interpretation — The outcome measures recommended here are structured around specific etiologies of LBP, span a patient’s entire cycle of care, and allow for risk adjustment. Thus, when implemented, this set can be expected to facilitate meaningful comparisons and ultimately provide a continuous feedback loop, enabling ongoing improvements in quality of care. Much work lies ahead in implementation, revision, and validation of this set, but it is an essential first step toward establishing a community of LBP providers focused on maximizing the value of the care we deliver.

Psychiatric disorders and major spine surgery: epidemiology and perioperative outcomes.

Study Design. Analysis of the National Hospital Discharge Survey database from 1990 to 2007. Objective. To evaluate the influence of preoperative depression, anxiety, schizophrenia, or dementia on in-hospital (1) adverse events, (2) mortality, and (3) nonroutine discharge in patients undergoing major spine surgery. Summary of Background Data. Psychiatric comorbidity is a known risk factor for impaired health-related quality of life and poor long-term outcomes after spine surgery, yet little is known about its impact in the perioperative spine surgery setting. Methods. Using the National Hospital Discharge Survey database, all patients undergoing either spinal fusion or laminectomy between 1990 and 2007 were identified and separated into groups with and without psychiatric disorders. Multivariable regression analysis was performed for each of the outcome variables. Results. Between 1990 and 2007, a total estimated number of 5,382,343 spinal fusions and laminectomies were performed. The prevalence of diagnosed depression, anxiety, and schizophrenia among the study population increased significantly over time. Depression, anxiety, schizophrenia, and dementia were associated with higher rates of nonroutine discharge. Depression, schizophrenia, and dementia were associated with higher rates of adverse events. Dementia was the only psychiatric disorder associated with a higher risk of in-hospital mortality. Conclusion. Patients with preoperative psychiatric disorders undergoing major spine surgery are at increased risk for perioperative adverse events and posthospitalization care, but its effect in perioperative mortality is more limited. Presurgical psychological screening of candidates undergoing spine surgery might ultimately lead to the enhancement of perioperative outcomes in this growing segment of the US population. Level of Evidence: N/A

Economic benefit to society at large of total knee arthroplasty in younger patients: a Markov analysis.

BACKGROUND To our knowledge, the economic implications of total knee arthroplasty to society at large have not been assessed with specific consideration of the young working population with osteoarthritis of the knee. The goal of the present study was to use a Markov analysis to estimate the overall average cost to society--in terms of medical expenses and lost wages--of delaying early total knee arthroplasty in favor of nonoperative treatment for end-stage knee osteoarthritis in a hypothetical fifty-year-old patient. METHODS A Markov state-transition decision model was constructed to compare the overall average cost over thirty years of total knee arthroplasty with the average thirty-year cost of nonoperative treatment for a fifty-year-old patient with end-stage osteoarthritis. Earned income, lost wages, and direct medical costs related to nonoperative treatment and to total knee arthroplasty, including revisions and complications, were considered. A sensitivity analysis was performed to assess the effect that variation of key model parameters had on the overall outcome of the model. RESULTS This Markov model favored early total knee arthroplasty over nonoperative treatment across all plausible values for most input parameters assessed during one-way sensitivity analysis. Total knee arthroplasty was more expensive during the first 3.5 years because of higher initial costs, but over thirty years the cost benefit of total knee arthroplasty was

Clinical sequelae after rhBMP-2 use in a minimally invasive transforaminal lumbar interbody fusion

69,800 (2012 U.S. dollars). Only when lost wages were <17.7 equivalent work days per year for patients treated nonoperatively or when the rate of returning to work after total knee arthroplasty was <81% did the model favor nonoperative treatment. CONCLUSIONS The results of the current study demonstrated that the total economic cost to society for treatment of severe knee osteoarthritis in a relatively young working person is markedly lower with total knee arthroplasty than it is with nonoperative treatment. The increasing financial restrictions on health-care providers in the U.S. necessitate careful consideration of the economic impact of different treatment options from the societal perspective. CLINICAL RELEVANCE The results of this model illustrate the need to account for the implications of treatment choices, not only at the individual patient level, but also for society at large. When deciding among available treatment options, patients, physicians, payers, and policymakers must consider individual treatment cost and effectiveness but also should account for future potential earnings generated when a treatment may restore a patients ability to contribute to society.

Allogeneic blood transfusions and postoperative infections after lumbar spine surgery

BACKGROUND CONTEXT Recent reports of postoperative radiculitis, bone osteolysis, and symptomatic ectopic bone formation after recombinant human bone morphogenetic protein-2 (rhBMP-2) use in transforaminal lumbar interbody fusions (TLIFs) are a cause for concern. PURPOSE To determine the clinical and radiographic complications associated with BMP utilization in a minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) environment. STUDY DESIGN/SETTING Retrospective clinical case series at a single institution. PATIENT SAMPLE Five hundred seventy-three consecutive patients undergoing an MIS-TLIF. OUTCOME MEASURES Reoperation rates and total costs associated with complications of rhBMP-2 use and pseudarthrosis. METHODS A retrospective review of 610 consecutive patients undergoing an MIS-TLIF (2007-2010) by a single surgeon at our institution was performed (mean age 48.7 years, range 26-82 years). All patients underwent an MIS laminectomy with bilateral facetectomy, single TLIF cage, unilateral pedicle screw fixation, and 12 mg (large kit) or 4.2 mg (small kit) of rhBMP-2. The BMP-2 collagen-soaked sponge was placed anteriorly in the disc space, followed by local bone graft, and then the cage was filled only with local bone and no BMP-2. Patients were evaluated at 6 months and 1 year with computed tomography (CT) scan. Those demonstrating neuroforaminal bone growth, osteolysis/cage migration, or pseudarthrosis were reviewed, and cost data including direct cost/procedure for both index and revision surgeries were collected. RESULTS Of the 573 patients, 10 (1.7%) underwent 15 additional procedures based on recalcitrant radiculopathy and CT evidence of neuroforaminal bone growth, vertebral body osteolysis, and/or cage migration. Thirty-nine patients (6.8%) underwent reoperation for clinically symptomatic pseudarthrosis. Bone overgrowth was associated with nerve impingement and radiculopathy in all 10 patients (small kit, n=9; large kit, n=1). Osteolysis and cage migration occurred in 2 (20%) of these same 10 patients. Average total costs were calculated per procedure (

An Anatomical Study of the Mid-Lateral Pars Relative to the Pedicle Footprint in the Lower Lumbar Spine

19,224), and the costs for reoperation equaled

In vivo Loads in the Lumbar L3-4 Disc during a Weight Lifting Extension

14,785 per encounter for neuroforaminal bone growth and

An anatomic and radiographic study of lumbar facets relevant to percutaneous transfacet fixation.

20,267 for pseudarthrosis. CONCLUSIONS Symptomatic ectopic bone formation, vertebral osteolysis, and pseudarthrosis are recognized complications with the use of rhBMP-2 in MIS-TLIFs. Potential causes include improper dosage and a closed space that prevents the egress of the postoperative BMP-2 fluid collection. Management of these complications has a substantial cost for the patient and the surgeon and needs to be considered with the off-label use of rhBMP-2.

In Vivo Morphological Features of Human Lumbar Discs

BACKGROUND CONTEXT Allogeneic blood transfusions have an immunomodulating effect, and the previous studies in other fields of medicine demonstrated an increased risk of infections after administration of allogeneic blood transfusions. PURPOSE Our primary null hypothesis is that exposure to allogeneic blood transfusion in patients undergoing lumbar spine surgery is not associated with postoperative infections after controlling for patient and treatment characteristics. Second, we assessed if there was a dose-response relationship per unit of blood transfused. STUDY DESIGN/SETTING This is a retrospective cohort study from a tertiary care spine referral center. PATIENT SAMPLE A total of 3,721 patients underwent laminectomy and/or arthrodesis of the lumbar spine. OUTCOMES MEASURES Postoperative infections, pneumonia, endocarditis, meningitis, urinary tract infection, central venous line infection, surgical site infection, and sepsis, within 90 days after lumbar spine surgery were included. METHODS Multivariable logistic regression analyses were used to assess the relationship of perioperative allogeneic blood transfusion with specific and overall postoperative infections accounting for age, duration of surgery, duration of hospital stay, comorbidity status, preoperative hemoglobin, sex, type of operation, multilevel treatment, operative approach, and year of surgery. RESULTS The adjusted odds ratio for exposure to allogeneic blood transfusion from multivariable logistic regression analysis was 2.6 for any postoperative infection (95% confidence interval [CI]: 1.7-3.9, p<.001); 2.2 for urinary tract infections (95% CI: 1.3-3.9, p=.004); 2.3 for pneumonia (95% CI: 0.96-5.3, p=.062); and 2.6 for surgical site infection requiring incision and drainage (95% CI: 1.3-5.3, p=.007). Secondary analyses demonstrated no dose-response relationship between the number of blood units transfused and any of the postoperative infections. Because of the low number of endocarditis (1 case, 0.031%), meningitis (1 case, 0.031%), central venous line infection (1 case, 0.031%), and sepsis (14 cases, 0.43%), we abstained from multivariable analysis. CONCLUSIONS Conscious of the limitations of this retrospective study, our data suggest an increased risk of surgical site infection, urinary tract infection, and overall postoperative infections, but not pneumonia, after exposure to allogeneic blood transfusion in patients undergoing lumbar spine surgery. These findings should be taken into account when considering blood transfusion and developing transfusion policies for patients undergoing lumbar spine procedures.

Sagittal plane rotation center of lower lumbar spine during a dynamic weight-lifting activity.

Study Design. An anatomic study that describes the relationship of the pedicle center to the mid-lateral pars (MLP) in the lower lumbar spine as a guide to pedicle screw placement. Objective. Describe morphometric data of the lower lumbar pedicles, the unique coronal pedicle footprints of L4 and L5, and their impact on the relationship of the pedicle center to the MLP. Summary of Background Data. Traditional medial-lateral starting points for lumbar pedicle screws use the facet as an anatomic reference for all lumbar levels. The facet is often a difficult landmark to use secondary to degenerative changes and the desire to minimize damage to the facet capsule in the most cephalad level. These techniques can also result in pedicle violation particularly in the lower lumbar spine. Use of the nonarthritic MLP is proposed in this study as an alternative anatomic reference point for the pedicle center. Methods. Seventy-two pedicles (L3–S1) from embalmed cadaveric spines were used. Linear and angular dimensions of the pedicle were measured, including the degree of coronal pedicle tilt of L4 and L5. The center of the pedicle relative to the MLP and relative to the midline of the base of the transverse process was measured. The axial superior facet angle and angle of pedicle screw insertion were also measured. Results. The minimum pedicle width was 10.9 and 12.4 mm and the coronal pedicle tilt was 36° and 55° for L4 and L5, respectively. A classification of 2 types of L5 pedicles relevant to pedicle center location was developed. In the medial-lateral direction, the pedicle center is 2.9 mm lateral to the MLP at L3 and L4. At L5, it is 1.5 and 4.5 mm lateral to the MLP for a type I and type II pedicle, respectively. In the superior-inferior direction, the pedicle center is 1 mm superior to the midline of the transverse process base for all lower lumbar levels. Significant differences between a type I and II L5 pedicle were a larger pedicle width and distance of the pedicle center to the MLP for a type II pedicle. The difference between the axial pedicle screw insertion angle and anatomic superior facet angles was 8° from L4–S1. Conclusion. The MLP is a reliable anatomic reference point for the center of the pedicle in the lower lumbarspine. Consideration needs to be taken when inserting pedicle screws at L4 and L5 because of the degree of their coronal tilts and unique pedicle footprints. It is important to distinguish a type I from type II L5 pedicle as a type II pedicle is wider, has a more lateral pedicle center relative to the MLP, and has the potential for lateral screw placement while still remaining within the pedicle.