Meic H. Schmidt, Frederick A. Boop, Neil A. Martin and Jonathan R. Slotkin
Jonathan R. Slotkin, Alfred S. Casale, Glenn D. Steele Jr. and Steven A. Toms
Comparative effectiveness research (CER) represents an evolution in clinical decision-making research that allows for the study of heterogeneous groups of patients with complex diseases processes. It has foundations in decision science, reliability science, and health care policy research. Health care finance will increasingly rely on CER for guidance in the coming years. There is increasing awareness of the importance of decreasing unwarranted variation in health care delivery. In the past 7 years, Geisinger Health System has performed broad reengineering of its acute episodic and chronic care delivery models utilizing macrosystem-level application of CER principles. These provider-driven process initiatives have resulted in significant improvement across all segments of care delivery, improved patient outcomes, and notable cost containment. These programs have led to the creation of novel pricing models, and when “hardwired” throughout a care delivery system, they can lead to correct medical decision making by 100% of providers in all patient encounters. Neurosurgery as a specialty faces unique challenges and opportunities with respect to broad adoption and application of CER techniques.
Kevin T. Foley, Eric J. Woodard, Jonathan R. Slotkin, Cassandra K. Mayotte, Abigail C. Baldwin, Michael C. Brown and Brian J. Hess
The authors’ goal in this study was to investigate the use of a novel, bioresorbable, osteoconductive, wet-field mineral-organic bone adhesive composed of tetracalcium phosphate and phosphoserine (TTCP-PS) for cranial bone flap fixation and compare it with conventional low-profile titanium plates and self-drilling screws.
An ovine craniotomy surgical model was used to evaluate the safety and efficacy of TTCP-PS over 2 years. Bilateral cranial defects were created in 41 sheep and were replaced in their original position. The gaps (kerfs) were completely filled with TTCP-PS (T1 group), half-filled with TTCP-PS (T2 group), or left empty and the flaps fixated by plates and screws as a control (C group). At 12 weeks, 1 year, and 2 years following surgery, the extent of bone healing, local tissue effects, and remodeling of the TTCP-PS were analyzed using macroscopic observations and histopathological and histomorphometric analyses. Flap fixation strength was evaluated by biomechanical testing at 12 weeks and 1 year postoperatively.
No adverse local tissue effects were observed in any group. At 12 weeks, the bone flap fixation strengths in test group 1 (1689 ± 574 N) and test group 2 (1611 ± 501 N) were both statistically greater (p = 0.01) than that in the control group (663 ± 385 N). From 12 weeks to 1 year, the bone flap fixation strengths increased significantly (p < 0.05) for all groups. At 1 year, the flap fixation strength in test group 1 (3240 ± 423 N) and test group 2 (3212 ± 662 N) were both statistically greater (p = 0.04 and p = 0.02, respectively) than that in the control group (2418 ± 1463 N); however, there was no statistically significant difference in the strengths when comparing the test groups at both timepoints. Test group 1 had the best overall performance based on histomorphometric evaluation and biomechanical testing. At 2 years postoperatively, the kerfs filled with TTCP-PS had histological evidence of osteoconduction and replacement of TTCP-PS by bone with nearly complete osteointegration.
TTCP-PS was demonstrated to be safe and effective for cranial flap fixation in an ovine model. In this study, the bioresorbable, osteoconductive bone adhesive appeared to have multiple advantages over standard plate-and-screw bone flap fixation, including biomechanical superiority, more complete and faster bony healing across the flap kerfs without fibrosis, and the minimization of bone flap and/or hardware migration and loosening. These properties of TTCP-PS may improve human cranial bone flap fixation and cranioplasty.
Case report and review of the literature
Patrick J. Codd, Ron I. Riesenburger, Paul Klimo Jr., Jonathan R. Slotkin and Edward R. Smith
✓ Aneurysmal bone cysts (ABCs) are benign, highly vascular osseous lesions characterized by cystic, blood-filled spaces surrounded by thin perimeters of expanded bone. Children and young adults are most often affected by spinal ABCs; more than 75% of patients are younger than 20 years old at presentation. Although ABCs have been documented in all areas of the axial and appendicular skeleton, ABCs of the spine present unique challenges due to the risk of vertebral destabilization, pathological fracture and vertebral body (VB) collapse, and neurological compromise. The authors describe the case of an 8-year-old child who presented with low-back pain and was subsequently found to have a lumbar ABC causing vertebra plana of the L-3 VB. They also review the literature on ABCs of the spine. This case highlights the importance of considering an ABC in the differential diagnosis when vertebra plana is seen in pediatric patients.
Anthony L. Asher, Panagiotis Kerezoudis, Praveen V. Mummaneni, Erica F. Bisson, Steven D. Glassman, Kevin T. Foley, Jonathan R. Slotkin, Eric A. Potts, Mark E. Shaffrey, Christopher I. Shaffrey, Domagoj Coric, John J. Knightly, Paul Park, Kai-Ming Fu, Clinton J. Devin, Kristin R. Archer, Silky Chotai, Andrew K. Chan, Michael S. Virk and Mohamad Bydon
Patient-reported outcomes (PROs) play a pivotal role in defining the value of surgical interventions for spinal disease. The concept of minimum clinically important difference (MCID) is considered the new standard for determining the effectiveness of a given treatment and describing patient satisfaction in response to that treatment. The purpose of this study was to determine the MCID associated with surgical treatment for degenerative lumbar spondylolisthesis.
The authors queried the Quality Outcomes Database registry from July 2014 through December 2015 for patients who underwent posterior lumbar surgery for grade I degenerative spondylolisthesis. Recorded PROs included scores on the Oswestry Disability Index (ODI), EQ-5D, and numeric rating scale (NRS) for leg pain (NRS-LP) and back pain (NRS-BP). Anchor-based (using the North American Spine Society satisfaction scale) and distribution-based (half a standard deviation, small Cohen’s effect size, standard error of measurement, and minimum detectable change [MDC]) methods were used to calculate the MCID for each PRO.
A total of 441 patients (80 who underwent laminectomies alone and 361 who underwent fusion procedures) from 11 participating sites were included in the analysis. The changes in functional outcome scores between baseline and the 1-year postoperative evaluation were as follows: 23.5 ± 17.4 points for ODI, 0.24 ± 0.23 for EQ-5D, 4.1 ± 3.5 for NRS-LP, and 3.7 ± 3.2 for NRS-BP. The different calculation methods generated a range of MCID values for each PRO: 3.3–26.5 points for ODI, 0.04–0.3 points for EQ-5D, 0.6–4.5 points for NRS-LP, and 0.5–4.2 points for NRS-BP. The MDC approach appeared to be the most appropriate for calculating MCID because it provided a threshold greater than the measurement error and was closest to the average change difference between the satisfied and not-satisfied patients. On subgroup analysis, the MCID thresholds for laminectomy-alone patients were comparable to those for the patients who underwent arthrodesis as well as for the entire cohort.
The MCID for PROs was highly variable depending on the calculation technique. The MDC seems to be a statistically and clinically sound method for defining the appropriate MCID value for patients with grade I degenerative lumbar spondylolisthesis. Based on this method, the MCID values are 14.3 points for ODI, 0.2 points for EQ-5D, 1.7 points for NRS-LP, and 1.6 points for NRS-BP.
Praveen V. Mummaneni, Mohamad Bydon, Mohammed Ali Alvi, Andrew K. Chan, Steven D. Glassman, Kevin T. Foley, Eric A. Potts, Christopher I. Shaffrey, Mark E. Shaffrey, Domagoj Coric, John J. Knightly, Paul Park, Michael Y. Wang, Kai-Ming Fu, Jonathan R. Slotkin, Anthony L. Asher, Michael S. Virk, Panagiotis Kerezoudis, Jian Guan, Regis W. Haid and Erica F. Bisson
Since the enactment of the Affordable Care Act in 2010, providers and hospitals have increasingly prioritized patient-centered outcomes such as patient satisfaction in an effort to adapt the “value”-based healthcare model. In the current study, the authors queried a prospectively maintained multiinstitutional spine registry to construct a predictive model for long-term patient satisfaction among patients undergoing surgery for Meyerding grade I lumbar spondylolisthesis.
The authors queried the Quality Outcomes Database for patients undergoing surgery for grade I lumbar spondylolisthesis between July 1, 2014, and June 30, 2016. The primary outcome of interest for the current study was patient satisfaction as measured by the North American Spine Surgery patient satisfaction index, which is measured on a scale of 1–4, with 1 indicating most satisfied and 4 indicating least satisfied. In order to identify predictors of higher satisfaction, the authors fitted a multivariable proportional odds logistic regression model for ≥ 2 years of patient satisfaction after adjusting for an array of clinical and patient-specific factors. The absolute importance of each covariate in the model was computed using an importance metric defined as Wald chi-square penalized by the predictor degrees of freedom.
A total of 502 patients, out of a cohort of 608 patients (82.5%) with grade I lumbar spondylolisthesis, undergoing either 1- or 2-level decompression (22.5%, n = 113) or 1-level decompression and fusion (77.5%, n = 389), met the inclusion criteria; of these, 82.1% (n = 412) were satisfied after 2 years. On univariate analysis, satisfied patients were more likely to be employed and working (41.7%, n = 172, vs 24.4%, n = 22; overall p = 0.001), more likely to present with predominant leg pain (23.1%, n = 95, vs 11.1%, n = 10; overall p = 0.02) but more likely to present with lower Numeric Rating Scale score for leg pain (median and IQR score: 7 [5–9] vs 8 [6–9]; p = 0.05). Multivariable proportional odds logistic regression revealed that older age (OR 1.57, 95% CI 1.09–2.76; p = 0.009), preoperative active employment (OR 2.06, 95% CI 1.27–3.67; p = 0.015), and fusion surgery (OR 2.3, 95% CI 1.30–4.06; p = 0.002) were the most important predictors of achieving satisfaction with surgical outcome.
Current findings from a large multiinstitutional study indicate that most patients undergoing surgery for grade I lumbar spondylolisthesis achieved long-term satisfaction. Moreover, the authors found that older age, preoperative active employment, and fusion surgery are associated with higher odds of achieving satisfaction.
Andrew K. Chan, Erica F. Bisson, Mohamad Bydon, Steven D. Glassman, Kevin T. Foley, Eric A. Potts, Christopher I. Shaffrey, Mark E. Shaffrey, Domagoj Coric, John J. Knightly, Paul Park, Michael Y. Wang, Kai-Ming Fu, Jonathan R. Slotkin, Anthony L. Asher, Michael S. Virk, Panagiotis Kerezoudis, Mohammed Ali Alvi, Jian Guan, Regis W. Haid and Praveen V. Mummaneni
The optimal minimally invasive surgery (MIS) approach for grade 1 lumbar spondylolisthesis is not clearly elucidated. In this study, the authors compared the 24-month patient-reported outcomes (PROs) after MIS transforaminal lumbar interbody fusion (TLIF) and MIS decompression for degenerative lumbar spondylolisthesis.
A total of 608 patients from 12 high-enrolling sites participating in the Quality Outcomes Database (QOD) lumbar spondylolisthesis module underwent single-level surgery for degenerative grade 1 lumbar spondylolisthesis, of whom 143 underwent MIS (72 MIS TLIF [50.3%] and 71 MIS decompression [49.7%]). Surgeries were classified as MIS if there was utilization of percutaneous screw fixation and placement of a Wiltse plane MIS intervertebral body graft (MIS TLIF) or if there was a tubular decompression (MIS decompression). Parameters obtained at baseline through at least 24 months of follow-up were collected. PROs included the Oswestry Disability Index (ODI), numeric rating scale (NRS) for back pain, NRS for leg pain, EuroQol-5D (EQ-5D) questionnaire, and North American Spine Society (NASS) satisfaction questionnaire. Multivariate models were constructed to adjust for patient characteristics, surgical variables, and baseline PRO values.
The mean age of the MIS cohort was 67.1 ± 11.3 years (MIS TLIF 62.1 years vs MIS decompression 72.3 years) and consisted of 79 (55.2%) women (MIS TLIF 55.6% vs MIS decompression 54.9%). The proportion in each cohort reaching the 24-month follow-up did not differ significantly between the cohorts (MIS TLIF 83.3% and MIS decompression 84.5%, p = 0.85). MIS TLIF was associated with greater blood loss (mean 108.8 vs 33.0 ml, p < 0.001), longer operative time (mean 228.2 vs 101.8 minutes, p < 0.001), and longer length of hospitalization (mean 2.9 vs 0.7 days, p < 0.001). MIS TLIF was associated with a significantly lower reoperation rate (14.1% vs 1.4%, p = 0.004). Both cohorts demonstrated significant improvements in ODI, NRS back pain, NRS leg pain, and EQ-5D at 24 months (p < 0.001, all comparisons relative to baseline). In multivariate analyses, MIS TLIF—as opposed to MIS decompression alone—was associated with superior ODI change (β = −7.59, 95% CI −14.96 to −0.23; p = 0.04), NRS back pain change (β = −1.54, 95% CI −2.78 to −0.30; p = 0.02), and NASS satisfaction (OR 0.32, 95% CI 0.12–0.82; p = 0.02).
For symptomatic, single-level degenerative spondylolisthesis, MIS TLIF was associated with a lower reoperation rate and superior outcomes for disability, back pain, and patient satisfaction compared with posterior MIS decompression alone. This finding may aid surgical decision-making when considering MIS for degenerative lumbar spondylolisthesis.
Anthony L. Asher, John Knightly, Praveen V. Mummaneni, Mohammed Ali Alvi, Matthew J. McGirt, Yagiz U. Yolcu, Andrew K. Chan, Steven D. Glassman, Kevin T. Foley, Jonathan R. Slotkin, Eric A. Potts, Mark E. Shaffrey, Christopher I. Shaffrey, Regis W. Haid Jr., Kai-Ming Fu, Michael Y. Wang, Paul Park, Erica F. Bisson, Robert E. Harbaugh and Mohamad Bydon
The Quality Outcomes Database (QOD), formerly known as the National Neurosurgery Quality Outcomes Database (N2QOD), was established by the NeuroPoint Alliance (NPA) in collaboration with relevant national stakeholders and experts. The overarching goal of this project was to develop a centralized, nationally coordinated effort to allow individual surgeons and practice groups to collect, measure, and analyze practice patterns and neurosurgical outcomes. Specific objectives of this registry program were as follows: “1) to establish risk-adjusted national benchmarks for both the safety and effectiveness of neurosurgical procedures, 2) to allow practice groups and hospitals to analyze their individual morbidity and clinical outcomes in real time, 3) to generate both quality and efficiency data to support claims made to public and private payers and objectively demonstrate the value of care to other stakeholders, 4) to demonstrate the comparative effectiveness of neurosurgical and spine procedures, 5) to develop sophisticated ‘risk models’ to determine which subpopulations of patients are most likely to benefit from specific surgical interventions, and 6) to facilitate essential multicenter trials and other cooperative clinical studies.” The NPA has launched several neurosurgical specialty modules in the QOD program in the 7 years since its inception including lumbar spine, cervical spine, and spinal deformity and cerebrovascular and intracranial tumor. The QOD Spine modules, which are the primary subject of this paper, have evolved into the largest North American spine registries yet created and have resulted in unprecedented cooperative activities within our specialty and among affiliated spine care practitioners. Herein, the authors discuss the experience of QOD Spine programs to date, with a brief description of their inception, some of the key achievements and milestones, as well as the recent transition of the spine modules to the American Spine Registry (ASR), a collaboration between the American Association of Neurological Surgeons and the American Academy of Orthopaedic Surgeons (AAOS).
Andrew K. Chan, Erica F. Bisson, Mohamad Bydon, Steven D. Glassman, Kevin T. Foley, Eric A. Potts, Christopher I. Shaffrey, Mark E. Shaffrey, Domagoj Coric, John J. Knightly, Paul Park, Michael Y. Wang, Kai-Ming Fu, Jonathan R. Slotkin, Anthony L. Asher, Michael S. Virk, Panagiotis Kerezoudis, Silky Chotai, Anthony M. DiGiorgio, Regis W. Haid and Praveen V. Mummaneni
The AANS launched the Quality Outcomes Database (QOD), a prospective longitudinal registry that includes demographic, clinical, and patient-reported outcome (PRO) data to measure the safety and quality of spine surgery. Registry data offer “real-world” insights into the utility of spinal fusion and decompression surgery for lumbar spondylolisthesis. Using the QOD, the authors compared the initial 12-month outcome data for patients undergoing fusion and those undergoing laminectomy alone for grade 1 degenerative lumbar spondylolisthesis.
Data from 12 top enrolling sites were analyzed and 426 patients undergoing elective single-level spine surgery for degenerative grade 1 lumbar spondylolisthesis were found. Baseline, 3-month, and 12-month follow-up data were collected and compared, including baseline clinical characteristics, readmission rates, reoperation rates, and PROs. The PROs included Oswestry Disability Index (ODI), back and leg pain numeric rating scale (NRS) scores, and EuroQol–5 Dimensions health survey (EQ-5D) results.
A total of 342 (80.3%) patients underwent fusion, with the remaining 84 (19.7%) undergoing decompression alone. The fusion cohort was younger (60.7 vs 69.9 years, p < 0.001), had a higher mean body mass index (31.0 vs 28.4, p < 0.001), and had a greater proportion of patients with back pain as a major component of their initial presentation (88.0% vs 60.7%, p < 0.001). There were no differences in 12-month reoperation rate (4.4% vs 6.0%, p = 0.93) and 3-month readmission rates (3.5% vs 1.2%, p = 0.45). At 12 months, both cohorts improved significantly with regard to ODI, NRS back and leg pain, and EQ-5D (p < 0.001, all comparisons). In adjusted analysis, fusion procedures were associated with superior 12-month ODI (β −4.79, 95% CI −9.28 to −0.31; p = 0.04).
Surgery for grade 1 lumbar spondylolisthesis—regardless of treatment strategy—was associated with significant improvements in disability, back and leg pain, and quality of life at 12 months. When adjusting for covariates, fusion surgery was associated with superior ODI at 12 months. Although fusion procedures were associated with a lower rate of reoperation, there was no statistically significant difference at 12 months. Further study must be undertaken to assess the durability of either surgical strategy in longer-term follow-up.