Jaes C. Jones, Jacob A. Miller, Dattanand M. Sudarshana, Nicolas R. Thompson, Edward C. Benzel and Thomas E. Mroz
In 2009, 2 randomized controlled trials demonstrated no improvement in pain following vertebral augmentation compared with sham surgery. However, a recent randomized trial demonstrated significant pain relief in patients following vertebroplasty compared to controls treated with conservative medical management. This study is a retrospective review of prospectively collected patient-reported quality of life (QOL) outcomes. The authors hypothesized that vertebral augmentation procedures offer a QOL benefit, but that this benefit would be diminished in patients with a history of depression and/or in patients undergoing vertebral augmentation at more than 1 level.
Multivariable linear regression was used to identify predictors of postoperative pain assessed using the Pain Disability Questionnaire (PDQ), Patient Health Questionnaire 9 (PHQ-9), and EQ-5D scores. Eleven candidate predictors were selected a priori: age, sex, smoking history, coronary artery disease, depression, diabetes, procedure location (thoracic, lumbar), BMI, prior spine surgery, procedure indication (metastases, osteoporosis/osteopenia, other), and number of levels (1, 2, 3, or more).
A total of 143 patients were included in the study. For each 10-year increase in age, postoperative PDQ scores decreased (improved) by 9.7 points (p < 0.001). Patients with osteoporosis/osteopenia had significantly higher (worse) postoperative PDQ scores (+17.97, p = 0.028) than patients with metastatic lesions. Male sex was associated with higher (worse) postoperative PHQ-9 scores (+2.48, p = 0.010). Compared to single-level augmentation, operations at 2 levels were associated with significantly higher PHQ-9 scores (+2.58, p = 0.017). Current smokers had significantly lower PHQ-9 scores (−1.98, p = 0.023) than never smokers. No predictors were associated with significantly different EQ-5D score.
Variables associated with worse postoperative PDQ scores included younger age and osteoporosis/osteopenia. Variables associated with decreased (better) postoperative PHQ-9 scores included female sex, single operative vertebral level, and positive smoking status (i.e., current smoker). These clinically relevant predictors may permit identification of patients who may benefit from vertebral augmentation.
Jacob A. Miller, Ehsan H. Balagamwala, Camille A. Berriochoa, Lilyana Angelov, John H. Suh, Edward C. Benzel, Alireza M. Mohammadi, Todd Emch, Anthony Magnelli, Andrew Godley, Peng Qi and Samuel T. Chao
Spine stereotactic radiosurgery (SRS) is a safe and effective treatment for spinal metastases. However, it is unknown whether this highly conformal radiation technique is suitable at instrumented sites given the potential for microscopic disease seeding. The authors hypothesized that spinal decompression with instrumentation is not associated with increased local failure (LF) following SRS.
A 2:1 propensity-matched retrospective cohort study of patients undergoing SRS for spinal metastasis was conducted. Patients with less than 1 month of radiographic follow-up were excluded. Each SRS treatment with spinal decompression and instrumentation was propensity matched to 2 controls without decompression or instrumentation on the basis of demographic, disease-related, dosimetric, and treatment-site characteristics. Standardized differences were used to assess for balance between matched cohorts.
The primary outcome was the 12-month cumulative incidence of LF, with death as a competing risk. Lesions demonstrating any in-field progression were considered LFs. Secondary outcomes of interest were post-SRS pain flare, vertebral compression fracture, instrumentation failure, and any Grade ≥ 3 toxicity. Cumulative incidences analysis was used to estimate LF in each cohort, which were compared via Gray’s test. Multivariate competing-risks regression was then used to adjust for prespecified covariates.
Of 650 candidates for the control group, 166 were propensity matched to 83 patients with instrumentation. Baseline characteristics were well balanced. The median prescription dose was 16 Gy in each cohort. The 12-month cumulative incidence of LF was not statistically significantly different between cohorts (22.8% [instrumentation] vs 15.8% [control], p = 0.25). After adjusting for the prespecified covariates in a multivariate competing-risks model, decompression with instrumentation did not contribute to a greater risk of LF (HR 1.21, 95% CI 0.74–1.98, p = 0.45). The incidences of post-SRS pain flare (11% vs 14%, p = 0.55), vertebral compression fracture (12% vs 22%, p = 0.04), and Grade ≥ 3 toxicity (1% vs 1%, p = 1.00) were not increased at instrumented sites. No instrumentation failures were observed.
In this propensity-matched analysis, LF and toxicity were similar among cohorts, suggesting that decompression with instrumentation does not significantly impact the efficacy or safety of spine SRS. Accordingly, spinal instrumentation may not be a contraindication to SRS. Future studies comparing SRS to conventional radiotherapy at instrumented sites in matched populations are warranted.
Roy Xiao, Jacob A. Miller, Navin C. Sabharwal, Daniel Lubelski, Vincent J. Alentado, Andrew T. Healy, Thomas E. Mroz and Edward C. Benzel
Improvements in imaging technology have steadily advanced surgical approaches. Within the field of spine surgery, assistance from the O-arm Multidimensional Surgical Imaging System has been established to yield superior accuracy of pedicle screw insertion compared with freehand and fluoroscopic approaches. Despite this evidence, no studies have investigated the clinical relevance associated with increased accuracy. Accordingly, the objective of this study was to investigate the clinical outcomes following thoracolumbar spinal fusion associated with O-arm–assisted navigation. The authors hypothesized that increased accuracy achieved with O-arm–assisted navigation decreases the rate of reoperation secondary to reduced hardware failure and screw misplacement.
A consecutive retrospective review of all patients who underwent open thoracolumbar spinal fusion at a single tertiary-care institution between December 2012 and December 2014 was conducted. Outcomes assessed included operative time, length of hospital stay, and rates of readmission and reoperation. Mixed-effects Cox proportional hazards modeling, with surgeon as a random effect, was used to investigate the association between O-arm–assisted navigation and postoperative outcomes.
Among 1208 procedures, 614 were performed with O-arm–assisted navigation, 356 using freehand techniques, and 238 using fluoroscopic guidance. The most common indication for surgery was spondylolisthesis (56.2%), and most patients underwent a posterolateral fusion only (59.4%). Although O-arm procedures involved more vertebral levels compared with the combined freehand/fluoroscopy cohort (4.79 vs 4.26 vertebral levels; p < 0.01), no significant differences in operative time were observed (4.40 vs 4.30 hours; p = 0.38). Patients who underwent an O-arm procedure experienced shorter hospital stays (4.72 vs 5.43 days; p < 0.01). O-arm–assisted navigation trended toward predicting decreased risk of spine-related readmission (0.8% vs 2.2%, risk ratio [RR] 0.37; p = 0.05) and overall readmissions (4.9% vs 7.4%, RR 0.66; p = 0.07). The O-arm was significantly associated with decreased risk of reoperation for hardware failure (2.9% vs 5.9%, RR 0.50; p = 0.01), screw misplacement (1.6% vs 4.2%, RR 0.39; p < 0.01), and all-cause reoperation (5.2% vs 10.9%, RR 0.48; p < 0.01). Mixed-effects Cox proportional hazards modeling revealed that O-arm–assisted navigation was a significant predictor of decreased risk of reoperation (HR 0.49; p < 0.01). The protective effect of O-arm–assisted navigation against reoperation was durable in subset analysis of procedures involving < 5 vertebral levels (HR 0.44; p = 0.01) and ≥ 5 levels (HR 0.48; p = 0.03). Further subset analysis demonstrated that O-arm–assisted navigation predicted decreased risk of reoperation among patients undergoing posterolateral fusion only (HR 0.39; p < 0.01) and anterior lumbar interbody fusion (HR 0.22; p = 0.03), but not posterior/transforaminal lumbar interbody fusion.
To the authors' knowledge, the present study is the first to investigate clinical outcomes associated with O-arm–assisted navigation following thoracolumbar spinal fusion. O-arm–assisted navigation decreased the risk of reoperation to less than half the risk associated with freehand and fluoroscopic approaches. Future randomized controlled trials to corroborate the findings of the present study are warranted.
Matthew D. Alvin, Jacob A. Miller, Daniel Lubelski, Benjamin P. Rosenbaum, Kalil G. Abdullah, Robert G. Whitmore, Edward C. Benzel and Thomas E. Mroz
Cost-effectiveness research in spine surgery has been a prominent focus over the last decade. However, there has yet to be a standardized method developed for calculation of costs in such studies. This lack of a standardized costing methodology may lead to conflicting conclusions on the cost-effectiveness of an intervention for a specific diagnosis. The primary objective of this study was to systematically review all cost-effectiveness studies published on spine surgery and compare and contrast various costing methodologies used.
The authors performed a systematic review of the cost-effectiveness literature related to spine surgery. All cost-effectiveness analyses pertaining to spine surgery were identified using the cost-effectiveness analysis registry database of the Tufts Medical Center Institute for Clinical Research and Health Policy, and the MEDLINE database. Each article was reviewed to determine the study subject, methodology, and results. Data were collected from each study, including costs, interventions, cost calculation method, perspective of cost calculation, and definitions of direct and indirect costs if available.
Thirty-seven cost-effectiveness studies on spine surgery were included in the present study. Twenty-seven (73%) of the studies involved the lumbar spine and the remaining 10 (27%) involved the cervical spine. Of the 37 studies, 13 (35%) used Medicare reimbursements, 12 (32%) used a case-costing database, 3 (8%) used cost-to-charge ratios (CCRs), 2 (5%) used a combination of Medicare reimbursements and CCRs, 3 (8%) used the United Kingdom National Health Service reimbursement system, 2 (5%) used a Dutch reimbursement system, 1 (3%) used the United Kingdom Department of Health data, and 1 (3%) used the Tricare Military Reimbursement system. Nineteen (51%) studies completed their cost analysis from the societal perspective, 11 (30%) from the hospital perspective, and 7 (19%) from the payer perspective. Of those studies with a societal perspective, 14 (38%) reported actual indirect costs.
Changes in cost have a direct impact on the value equation for concluding whether an intervention is cost-effective. It is essential to develop a standardized, accurate means of calculating costs. Comparability and transparency are essential, such that studies can be compared properly and policy makers can be appropriately informed when making decisions for our health care system based on the results of these studies.