Risk of adjacent level fracture after percutaneous vertebroplasty and kyphoplasty vs natural history for the management of osteoporotic vertebral compression fractures: a network meta-analysis of randomized controlled trials.

OBJECTIVES: Percutaneous vertebroplasty and kyphoplasty are common interventions for osteoporotic vertebral compression fractures. However, there is concern about an increased risk of adjacent-level fractures after treatment. This study aimed to compare the risk of adjacent-level fractures after vertebroplasty and kyphoplasty with the natural history after osteoporotic vertebral compression fractures. MATERIALS AND METHODS: A network meta-analysis of randomized controlled trials (RCTs) was conducted to evaluate the risk of adjacent-level fractures after vertebroplasty and kyphoplasty compared to the natural history after osteoporotic vertebral compression fractures. Frequentist network meta-analysis was conducted using the "netmeta" package, and heterogeneity was assessed using Q statistics. The pooled risk ratio (RR) and 95% confidence intervals (CI) were calculated using random effects. RESULTS: Twenty-three RCTs with a total of 2838 patients were included in the analysis. The network meta-analysis showed comparable risks of adjacent-level fractures between vertebroplasty, kyphoplasty, and natural history after osteoporotic vertebral compression fractures with a mean follow-up of 21.2 (range: 3-49.4 months). The pooled RR for adjacent-level fractures after kyphoplasty compared to natural history was 1.35 (95% CI, 0.78-2.34, p = 0.23) and for vertebroplasty compared to natural history was 1.16 (95% CI, 0.62-2.14) p = 0.51. The risk of bias assessment showed a low to moderate risk of bias among included RCTs. CONCLUSION: There was no difference in the risk of adjacent-level fractures after vertebroplasty and kyphoplasty compared to natural history after osteoporotic vertebral compression fractures. The inclusion of a large patient number and network meta-analysis of RCTs serve evidence-based clinical practice. CLINICAL RELEVANCE STATEMENT: The risk of adjacent-level fracture following percutaneous vertebroplasty or kyphoplasty is similar to that observed in the natural history after osteoporotic vertebral compression fractures. KEY POINTS: RCTs have examined the risk of adjacent-level fracture after intervention for osteoporotic vertebral compression fractures. There was no difference between vertebroplasty and kyphoplasty patients compared to the natural disease history for adjacent compression fractures. This is strong evidence that interventional treatments for these fractures do not increase the risk of adjacent fractures.

When the Physician Becomes the Patient: Considerations for Work, Life, and Leadership.

Most orthopaedic surgeons are unprepared for serious medical illnesses. In such cases, the unique work-related and personal considerations for orthopaedic surgeons affect their career, their practice partners, and their patients. Planning together as an orthopaedic business organization for such issues can provide a framework to better navigate these difficult situations. Understanding the considerations and stressors from the individual's perspective can help provide the appropriate level of support while maintaining privacy. Throughout these considerations, open communication regarding expectations and concerns and expressions of empathy are the cornerstones of dealing with physician illness. Being a physician-patient adds complexity to an already difficult and stressful profession. Further dialogue regarding the physician-patient experience can help increase awareness of this issue and allow organizations to create a structure to best manage this almost inevitable occurrence.

What Is the Clinical Benefit of Common Orthopaedic Procedures as Assessed by the PROMIS Versus Other Validated Outcomes Tools?

BACKGROUND: Patient-reported outcome measures (PROMs), including the Patient-reported Outcomes Measurement Information System (PROMIS), are increasingly used to measure healthcare value. The minimum clinically important difference (MCID) is a metric that helps clinicians determine whether a statistically detectable improvement in a PROM after surgical care is likely to be large enough to be important to a patient or to justify an intervention that carries risk and cost. There are two major categories of MCID calculation methods, anchor-based and distribution-based. This variability, coupled with heterogeneous surgical cohorts used for existing MCID values, limits their application to clinical care. QUESTIONS/PURPOSES: In our study, we sought (1) to determine MCID thresholds and attainment percentages for PROMIS after common orthopaedic procedures using distribution-based methods, (2) to use anchor-based MCID values from published studies as a comparison, and (3) to compare MCID attainment percentages using PROMIS scores to other validated outcomes tools such as the Hip Disability and Osteoarthritis Outcome Score (HOOS) and Knee Disability and Osteoarthritis Outcome Score (KOOS). METHODS: This was a retrospective study at two academic medical centers and three community hospitals. The inclusion criteria for this study were patients who were age 18 years or older and who underwent elective THA for osteoarthritis, TKA for osteoarthritis, one-level posterior lumbar fusion for lumbar spinal stenosis or spondylolisthesis, anatomic total shoulder arthroplasty or reverse total shoulder arthroplasty for glenohumeral arthritis or rotator cuff arthropathy, arthroscopic anterior cruciate ligament reconstruction, arthroscopic partial meniscectomy, or arthroscopic rotator cuff repair. This yielded 14,003 patients. Patients undergoing revision operations or surgery for nondegenerative pathologies and patients without preoperative PROMs assessments were excluded, leaving 9925 patients who completed preoperative PROMIS assessments and 9478 who completed other preoperative validated outcomes tools (HOOS, KOOS, numerical rating scale for leg pain, numerical rating scale for back pain, and QuickDASH). Approximately 66% (6529 of 9925) of patients had postoperative PROMIS scores (Physical Function, Mental Health, Pain Intensity, Pain Interference, and Upper Extremity) and were included for analysis. PROMIS scores are population normalized with a mean score of 50 ± 10, with most scores falling between 30 to 70. Approximately 74% (7007 of 9478) of patients had postoperative historical assessment scores and were included for analysis. The proportion who reached the MCID was calculated for each procedure cohort at 6 months of follow-up using distribution-based MCID methods, which included a fraction of the SD (1/2 or 1/3 SD) and minimum detectable change (MDC) using statistical significance (such as the MDC 90 from p < 0.1). Previously published anchor-based MCID thresholds from similar procedure cohorts and analogous PROMs were used to calculate the proportion reaching MCID. RESULTS: Within a given distribution-based method, MCID thresholds for PROMIS assessments were similar across multiple procedures. The MCID threshold ranged between 3.4 and 4.5 points across all procedures using the 1/2 SD method. Except for meniscectomy (3.5 points), the anchor-based PROMIS MCID thresholds (range 4.5 to 8.1 points) were higher than the SD distribution-based MCID values (2.3 to 4.5 points). The difference in MCID thresholds based on the calculation method led to a similar trend in MCID attainment. Using THA as an example, MCID attainment using PROMIS was achieved by 76% of patients using an anchor-based threshold of 7.9 points. However, 82% of THA patients attained MCID using the MDC 95 method (6.1 points), and 88% reached MCID using the 1/2 SD method (3.9 points). Using the HOOS metric (scaled from 0 to 100), 86% of THA patients reached the anchor-based MCID threshold (17.5 points). However, 91% of THA patients attained the MCID using the MDC 90 method (12.5 points), and 93% reached MCID using the 1/2 SD method (8.4 points). In general, the proportion of patients reaching MCID was lower for PROMIS than for other validated outcomes tools; for example, with the 1/2 SD method, 72% of patients who underwent arthroscopic partial meniscectomy reached the MCID on PROMIS Physical Function compared with 86% on KOOS. CONCLUSION: MCID calculations can provide clinical correlation for PROM scores interpretation. The PROMIS form is increasingly used because of its generalizability across diagnoses. However, we found lower proportions of MCID attainment using PROMIS scores compared with historical PROMs. By using historical proportions of attainment on common orthopaedic procedures and a spectrum of MCID calculation techniques, the PROMIS MCID benchmarks are realizable for common orthopaedic procedures. For clinical practices that routinely collect PROMIS scores in the clinical setting, these results can be used by individual surgeons to evaluate personal practice trends and by healthcare systems to quantify whether clinical care initiatives result in meaningful differences. Furthermore, these MCID thresholds can be used by researchers conducting retrospective outcomes research with PROMIS. LEVEL OF EVIDENCE: Level III, therapeutic study.

Update on the Diagnosis and Management of Spinal Infections.

Pyogenic spinal infections are uncommon, but their incidence has increased. Diagnosis is based on clinical, laboratory, and imaging findings. Delayed diagnosis occurs frequently and can lead to poor outcomes. Early radiographic findings are nonspecific; MRI is the best imaging study for diagnosis. The goal of treatment is to eradicate infection, prevent recurrence, preserve spinal stability, avoid deformity, relieve pain, and prevent or reverse neurologic deficit. Current guidelines recommend antibiotics be administered for 6 weeks if there is resolution of symptoms and normalization of inflammatory parameters. Surgery is required in patients with neurologic deficit, uncontrolled sepsis, spinal instability, deformity, and failure of medical treatment and to manage epidural abscess. Classic treatment of epidural abscess is surgical, but recent studies have challenged this approach. Surgical techniques used to manage these infections are varied; they include anterior, posterior, and combined approaches, and minimally invasive surgery. Current management has decreased mortality; however, the prognosis is affected by treatment failure, recurrent infection, or potential of persistent disability secondary to deformity, chronic pain, or permanent neurologic impairment.

Clinical significance of "positive" cervical spine MRI findings following a negative CT.

PURPOSE: To review and analyze the clinical significance of positive acute traumatic findings seen on MRI of the cervical spine (MRCS) following a negative CT of the cervical spine (CTCS) for trauma. METHODS: We performed a sub-cohort analysis of 54 patients with negative CTCS and a positive MRCS after spine trauma from the previous multicenter study of the Research Consortium of New England Centers for Trauma (ReCONECT). Both CTCS and MRCS were independently reviewed by two emergency radiologists and two spine surgeons. The surgeons also commented on the clinical significance of the traumatic findings seen on MRCS and grouped them into unstable, potentially unstable, and stable injuries. RESULTS: Among 35 unevaluable patients, MRCS showed one unstable (hyperextension) and two potentially unstable (hyperflexion) injuries. Subtle findings were seen on CTCS in 2 of 3 patients upon careful retrospective review that would have suggested these injuries. Of 19 patients presenting with cervicalgia, 2/5 (40%) patients with neurological deficit demonstrated clinically significant findings on MRCS with predisposing factors seen on CT. None of the 14 patients with isolated cervicalgia and no neurological deficit had clinically significant findings on their MRCS. CONCLUSION: While CTCS is adequate for clearing the cervical spine in patients with isolated cervicalgia, MRCS can play a critical role in patients with neurological deficits and normal CTCS. Clinically significant traumatic findings were seen in 8.5% of unevaluable patients on MRCS, though these injuries in fact could be identified on the CT in 2 of 3 patients upon careful retrospective review.

Disparities in Rates of Surgical Intervention Among Racial and Ethnic Minorities in Medicare Accountable Care Organizations.

OBJECTIVE: To assess the effect of Accountable Care Organizations (ACOs) on the use of surgical services among racial and ethnic minorities. BACKGROUND: Health reform efforts were expected to reduce healthcare disparities. The impact of ACOs on existing disparities in access to surgical care remains unknown. METHODS: We used national Medicare data (2009-2014) to compare rates of surgery among white, African American, Hispanic, and Asian Medicare beneficiaries for coronary artery bypass grafting, colectomy, total hip arthroplasty, hip fracture repair, and lumbar spine surgery. We performed a pre-post difference in differences analysis between African American, Hispanic, and Asian patients receiving surgical care in ACO and non-ACO organizations before and after the implementation of ACOs. The time period 2009 to 2011 was considered the pre-ACO period, and 2012 to 2014 the post-ACO period. RESULTS: Rates of surgical intervention in the ACO cohort were significantly lower (P < 0.001) as compared to non-ACOs for whites, African Americans, Hispanics, and Asians in both the pre- and post-ACO periods. There was no significant difference in the adjusted change in the rate of surgical interventions among minority patients as compared to whites in ACOs and non-ACOs between 2009 to 2011 and 2012 to 2014. The odds of receiving surgical intervention were lowest for minority patients in ACOs during the post-ACO period (P < 0.001). CONCLUSIONS: We found persistent differences in the use of surgery among racial and ethnic minorities between the time periods 2009 to 2011 and 2012 to 2014. These disparities were not impacted by the formation of ACOs. Programs that specifically incentivize ACOs to improve surgical access for minorities may be necessary.

Injuries to the Rigid Spine: What the Spine Surgeon Wants to Know.

The biomechanical stability of the spine is altered in patients with a rigid spine, rendering it vulnerable to fracture even from relatively minor impact. The rigid spine entities are ankylosing spondylitis (AS), diffuse idiopathic skeletal hyperostosis, degenerative spondylosis, and a surgically fused spine. The most common mechanism of injury resulting in fracture is hyperextension, which often leads to unstable injury in patients with a rigid spine per the recent AOSpine classification system. Due to the increased risk of spinal fractures in this population, performing a spine CT is the first step when a patient with a rigid spine presents with new back pain or suspected spinal trauma. In addition, there should be a low threshold for performing a non-contrast-enhanced spine MRI in patients with a rigid spine, especially those with AS who may have an occult fracture, epidural hematoma, or spinal cord injury. Unfortunately, owing to insufficient imaging and an unfamiliarity with fracture patterns in the setting of a rigid spine, fracture diagnosis is often delayed, leading to significant morbidity and even death. The radiologist's role is to recognize the imaging features of a rigid spine, identify any fractures at CT and MRI, and fully characterize the extent of injury. Reasons for surgical intervention include neurologic deficit or concern for deterioration, an unstable fracture, or the presence of an epidural hematoma. By understanding the imaging features of various rigid spine conditions and vigilantly examining images for occult fractures, the radiologist can avoid a missed or delayed diagnosis of an injured rigid spine. ©RSNA, 2019.

Development of a machine learning algorithm predicting discharge placement after surgery for spondylolisthesis.

PURPOSE: We aimed to develop a machine learning algorithm that can accurately predict discharge placement in patients undergoing elective surgery for degenerative spondylolisthesis. METHODS: The National Surgical Quality Improvement Program (NSQIP) database was used to select patients that underwent surgical treatment for degenerative spondylolisthesis between 2009 and 2016. Our primary outcome measure was non-home discharge which was defined as any discharge not to home for which we grouped together all non-home discharge destinations including rehabilitation facility, skilled nursing facility, and unskilled nursing facility. We used Akaike information criterion to select the most appropriate model based on the outcomes of the stepwise backward logistic regression. Four machine learning algorithms were developed to predict discharge placement and were assessed by discrimination, calibration, and overall performance. RESULTS: Nine thousand three hundred and thirty-eight patients were included. Median age was 63 (interquartile range [IQR] 54-71), and 63% (n = 5,887) were female. The non-home discharge rate was 18.6%. Our models included age, sex, diabetes, elective surgery, BMI, procedure, number of levels, ASA class, preoperative white blood cell count, and preoperative creatinine. The Bayes point machine was considered the best model based on discrimination (AUC = 0.753), calibration (slope = 1.111; intercept = - 0.002), and overall model performance (Brier score = 0.132). CONCLUSION: This study has shown that it is possible to create a predictive machine learning algorithm with both good accuracy and calibration to predict discharge placement. Using our methodology, this type of model can be developed for many other conditions and (elective) treatments. These slides can be retrieved under Electronic Supplementary Material.

Spectrum of diagnostic errors in cervical spine trauma imaging and their clinical significance.

PURPOSE: To describe and categorize diagnostic errors in cervical spine CT (CsCT) interpretation performed for trauma and to assess their clinical significance. METHODS: All CsCTs performed for trauma with diagnostic errors that came to our attention based on clinical or imaging follow-up or quality assurance peer review from 2004 to 2017 were included. The number of CsCTs performed at our institution during the same time interval was calculated. Errors were categorized as spinal/extraspinal, involving osseous/soft tissue structures, by anatomical site and level. Images were reviewed by a radiologist and two spine surgeons. For each error, the need for surgery, immobilization, CT angiogram of the neck, and MRI was assessed; if any of these were needed, the error was considered clinically significant. RESULTS: Of an approximate total 59,000 CsCTs, 56 reports containing diagnostic errors were included. Twelve were extraspinal, and 44 were spinal (26 fractures, 15 intervertebral disc protrusions, two subluxations, one lytic bone lesion). The most common sites of spinal fractures were vertebral body (n = 10) and transverse process (n = 8); the most common levels were C5 (n = 8) and C7 (n = 6). All (n = 26) fractures and two atlantooccipital subluxations were considered clinically significant, including three patients who would have required urgent surgical stabilization (two subluxations and one facet fracture). Two transverse processes fractures did not alter the need for surgical intervention/surgical approach, immobilization, or MRI. CONCLUSIONS: In our study, 66% of spinal diagnostic errors on CsCT were considered clinically significant, potentially altering clinical management. Transverse process and vertebral body fractures were commonly missed.

Correction to: Spectrum of diagnostic errors in cervical spine trauma imaging and their clinical significance.

The published version of this article unfortunately contained a mistake. Author given and family name Alessandrino Francesco was incorrectly interchanged. The correct presentation is given above. The original article has been corrected.

Critical analysis of trends in lumbar fusion for degenerative disorders revisited: influence of technique on fusion rate and clinical outcomes.

PURPOSE: Lumbar fusion for degenerative disorders is among the most common spine surgical procedures performed. The purpose of this study was to analyze fusion, complications, and clinical success for lumbar fusion performed with various surgical techniques as reported in the literature from 2000 to 2015 and compare with previous critical analysis of outcomes from 1980 to 2000. METHODS: A systematic review of the literature to identify all studies of adult lumbar fusion for degenerative disorders published between January 1, 2000, and August 31, 2015, was performed adhering to PRISMA guidelines. Studies were included if they enabled analysis of outcomes of individual fusion techniques. RESULTS: Data from 8599 patients extracted from 160 studies were recorded. Posterior and transforaminal lumbar interbody fusion (PLIF and TLIF) had significantly higher fusion rates compared to instrumented posterolateral fusion (PLF) (OR 3.20 and 2.46, respectively). Clinical success rate was statistically higher with MIS versus non-MIS fusion (OR 2.44). While methodological quality was higher in studies from 2000 to 2015 than prior decades, the outcomes of comparable procedures were about the same. CONCLUSIONS: Lumbar fusions for degenerative disorders from 2000 to 2015 demonstrate a trend toward more interbody fusions and MIS techniques than prior decades. Clinical success with MIS appears more likely than with non-MIS fusions, despite equivalent fusion and complication rates. While these data are intriguing, they should be interpreted cautiously considering the level of heterogeneity of the studies available. Further, high-quality comparative studies are warranted to better understand the relative benefits of more complex interbody and MIS fusions for these conditions. These slides can be retrieved under Electronic Supplementary Material.

CT for thoracic and lumbar spine fractures: Can CT findings accurately predict posterior ligament complex injury?

PURPOSE: This study aims to determine whether secondary CT findings can predict posterior ligament complex (PLC) injury in patients with acute thoracic (T) or lumbar (L) spine fractures. METHODS: This is a retrospective study of 105 patients with acute thoracic and lumbar spine fractures on CT, with MRI as the reference standard for PLC injury. Three readers graded CT for facet joint alignment (FJA), widening (FJW), pedicle or lamina fracture (PLF), spinous fracture (SPF), interspinous widening (ISW), vertebral translation (VBT), and posterior endplate fracture (PEF). Univariate and multivariate logistic regression analyses were performed separately for each reader to test for associations between CT and PLC injury, and diagnostic performance of CT was calculated. RESULTS: Fifty-three of 105 patients had PLC injury by MRI. Statistically significant predictors of PLC injury were VBT, PLF, ISW, and SPF. Using these four CT findings, odds of PLC injury ranged from 3.8 to 5.6 for one positive finding, but increased to 13.6-25.1 for two or more. At least one positive CT finding was found to yield average sensitivity of 82% and specificity 59%, while two or more yielded sensitivity 46% and specificity 88%. CONCLUSION: While no individual CT finding is sufficiently accurate to diagnose or exclude PLC injury, greater the number of positive CT findings (VBT, PLF, ISW, and SPF), the higher the odds of PLC injury. The presence of a single abnormal CT finding may warrant confirmatory MRI for PLC injury, while two or more CT findings may have adequate specificity to avoid need for MRI prior to surgical intervention. These slides can be retrieved under Electronic Supplementary Material.

Development of machine learning algorithms for prediction of discharge disposition after elective inpatient surgery for lumbar degenerative disc disorders.

OBJECTIVEIf not anticipated and prearranged, hospital stay can be prolonged while the patient awaits placement in a rehabilitation unit or skilled nursing facility following elective spine surgery. Preoperative prediction of the likelihood of postoperative discharge to any setting other than home (i.e., nonroutine discharge) after elective inpatient spine surgery would be helpful in terms of decreasing hospital length of stay. The purpose of this study was to use machine learning algorithms to develop an open-access web application for preoperative prediction of nonroutine discharges in surgery for elective inpatient lumbar degenerative disc disorders.METHODSThe American College of Surgeons National Surgical Quality Improvement Program was queried to identify patients who underwent elective inpatient spine surgery for lumbar disc herniation or lumbar disc degeneration between 2011 and 2016. Four machine learning algorithms were developed to predict nonroutine discharge and the best algorithm was incorporated into an open-access web application.RESULTSThe rate of nonroutine discharge for 26,364 patients who underwent elective inpatient surgery for lumbar degenerative disc disorders was 9.28%. Predictive factors selected by random forest algorithms were age, sex, body mass index, fusion, level, functional status, extent and severity of comorbid disease (American Society of Anesthesiologists classification), diabetes, and preoperative hematocrit level. On evaluation in the testing set (n = 5273), the neural network had a c-statistic of 0.823, calibration slope of 0.935, calibration intercept of 0.026, and Brier score of 0.0713. On decision curve analysis, the algorithm showed greater net benefit for changing management over all threshold probabilities than changing management on the basis of the American Society of Anesthesiologists classification alone or for all patients or for no patients. The model can be found here: https://sorg-apps.shinyapps.io/discdisposition/.CONCLUSIONSMachine learning algorithms show promising results on internal validation for preoperative prediction of nonroutine discharges. If found to be externally valid, widespread use of these algorithms via the open-access web application by healthcare professionals may help preoperative risk stratification of patients undergoing elective surgery for lumbar degenerative disc disorders.

The effect of short (2-weeks) versus long (6-weeks) post-operative restrictions following lumbar discectomy: a prospective randomized control trial.

PURPOSE: We sought to evaluate how short (2-week) versus long (6-week) post-operative restrictions following lumbar discectomy impacted outcomes and reherniation rates for a period up to 1 year following surgery. METHODS: This study included 108 patients undergoing index lumbar discectomy. Patients were randomized immediately following surgery. Outcomes included back and leg visual analog pain scales (VAS), Oswestry Disability Index (ODI), and reherniation rates at 2-weeks, 6-weeks, 3-months, and 1-year following surgery. Differences in reherniation rates were analyzed using Fisher's exact test. VAS and ODI scores were evaluated using Student's t test. RESULTS: Six patients (11%) in the 2-week restriction group had a reherniation event and four patients (7%) in the 6-week restriction group experienced a reherniation (p = 0.52). VAS back pain (p < 0.001), leg pain (p < 0.001), and ODI scores (p < 0.001) were significantly improved for both cohorts as compared to baseline at the 2-week time point and remained significantly improved through 1-year [VAS back (p < 0.001); VAS leg (p < 0.001); ODI (p < 0.001)]. No significant differences in ODI, VAS back, or VAS leg scores were detected at any of the time points between the 2- and 6-week restriction groups. CONCLUSIONS: The results of this randomized trial suggest equivalent clinical outcomes irrespective of the length of post-operative restriction. From a clinical perspective, if patients are deemed at low risk for a reherniation event they may be confidence that early return to activity at 2 weeks will not compromise outcomes and may not adversely impact the risk of reherniation. Level of Evidence II.

Is There Variation in Procedural Utilization for Lumbar Spine Disorders Between a Fee-for-Service and Salaried Healthcare System?

BACKGROUND: Whether compensation for professional services drives the use of those services is an important question that has not been answered in a robust manner. Specifically, there is a growing concern that spine care practitioners may preferentially choose more costly or invasive procedures in a fee-for-service system, irrespective of the underlying lumbar disorder being treated. QUESTIONS/PURPOSES: (1) Were proportions of interbody fusions higher in the fee-for-service setting as opposed to the salaried Department of Defense setting? (2) Were the odds of interbody fusion increased in a fee-for-service setting after controlling for indications for surgery? METHODS: Patients surgically treated for lumbar disc herniation, spinal stenosis, and spondylolisthesis (2006-2014) were identified. Patients were divided into two groups based on whether the surgery was performed in the fee-for-service setting (beneficiaries receive care at a civilian facility with expenses covered by TRICARE insurance) or at a Department of Defense facility (direct care). There were 28,344 patients in the entire study, 21,290 treated in fee-for-service and 7054 treated in Department of Defense facilities. Differences in the rates of fusion-based procedures, discectomy, and decompression between both healthcare settings were assessed using multinomial logistic regression to adjust for differences in case-mix and surgical indication. RESULTS: TRICARE beneficiaries treated for lumbar spinal disorders in the fee-for-service setting had higher odds of receiving interbody fusions (fee-for-service: 7267 of 21,290 [34%], direct care: 1539 of 7054 [22%], odds ratio [OR]: 1.25 [95% confidence interval 1.20-1.30], p < 0.001). Purchased care patients were more likely to receive interbody fusions for a diagnosis of disc herniation (adjusted OR 2.61 [2.36-2.89], p < 0.001) and for spinal stenosis (adjusted OR 1.39 [1.15-1.69], p < 0.001); however, there was no difference for patients with spondylolisthesis (adjusted OR 0.99 [0.84-1.16], p = 0.86). CONCLUSIONS: The preferential use of interbody fusion procedures was higher in the fee-for-service setting irrespective of the underlying diagnosis. These results speak to the existence of provider inducement within the field of spine surgery. This reality portends poor performance for surgical practices and hospitals in Accountable Care Organizations and bundled payment programs in which provider inducement is allowed to persist. LEVEL OF EVIDENCE: Level III, economic and decision analysis.

Relationship between size of disc and early postoperative outcomes after lumbar discectomy.

BACKGROUND: Previous studies suggest that patients with larger disc herniations (greater than 6 mm) will have better outcomes following discectomy. This has not been validated in a large series of patients. PURPOSE: We sought to empirically evaluate this relationship in a series of patients who had data collected prospectively as part of a randomized trial. METHODS: This retrospective review included 63 consecutive adult patients who underwent a single-level, primary lumbar discectomy. Outcomes were VAS for leg and back pain and the modified oswestry disability index (MODI). Statistical tests were used to compare patients using different cutoffs of preoperative disc diameters and disc volume removed. Regression analysis was performed to determine if there was a relationship between outcomes and the measured parameters. RESULTS: While patients who achieved substantial clinical benefit (SCB) for MODI had larger disc diameters, this relationship was not found for leg or back pain for any of the measured parameters. Using 5, 6, 7, or 8 mm as a cutoff for disc diameter demonstrated no differences. Regression analysis did not demonstrate a significant relationship between disc volume removed and final MODI scores. CONCLUSION: While patients with larger disc herniations on average might have a greater likelihood of superior clinical outcomes, the previously suggested "6 mm rule" was not supported.

The influence of adjacent level disc disease on discectomy outcomes.

PURPOSE: The state of adjacent level discs and its impact on surgical outcomes following single-level lumbar discectomy have not been previously investigated. The purpose of the present study was to determine if a significant relationship exists between the degree of preoperative adjacent level disc degeneration and post-operative clinical outcomes following lumbar discectomy. METHODS: This study retrospectively used preoperative magnetic resonance imaging (MRI) and prospectively collected data from a randomized clinical trial at two tertiary-care academic hospitals. Patients who underwent a primary, single-level lumbar discectomy were included. Exclusion criteria included prior lumbar surgery. Outcome measures were the Modified Oswestry Disability Index (ODI) score and Visual Analog Scale (VAS) scores for back and leg pain. These were recorded at baseline and at 3 months, 1, and 2 years postoperatively. An independent reviewer graded adjacent level disc degeneration on all preoperative MRIs using the Pfirrmann grading scale. These data were then analyzed for correlation with each outcome measure. RESULTS: Forty-seven patients were included in the study. No statistically significant correlations were found when comparing preoperative 3-month or 1-year postoperative scores or change from baseline of any outcome measure between Pfirrmann grades. Only about half the patients had 2-year follow-up, but at that time point a statistically significant difference in back VAS scores was observed between Pfirrmann groups. No other significant differences were observed at that point. CONCLUSIONS: The degree of preoperative adjacent level degeneration does not significantly affect functional or pain relief outcomes following lumbar discectomy up to 1 year after surgery.

Virtually bloodless posterior midline exposure of the lumbar spine using the "para-midline" fatty plane.

PURPOSE: The authors have developed a "para-midline" approach to the posterior lumbar spine using a virtually avascular surgical plane not previously described in the literature. It was their purpose to document consistent MRI presence of this plane and to prospectively evaluate its clinical use in terms of blood loss. METHODS: Fifty consecutive patients undergoing primary lumbar surgery on 1-3 levels were prospectively enrolled from September 2014 to May 2015. The para-midline approach was used in all cases. The deep lumbar fascia is longitudinally incised on either side of the spinous processes instead of directly in the midline, which reveals the para-midline fatty plane. Blood loss during the approach and overall blood loss were recorded for all patients. MRIs from each patient were reviewed by an experienced neuroradiologist to determine the presence of the para-midline fatty plane. RESULTS: There was no recorded blood loss during the approach for all procedures. The average overall blood loss was 60 cc (20-200 cc). No patient required a transfusion intraoperatively or postoperatively. The fatty para-midline plane was noted on preoperative MRI at all operated levels in all patients. The average width of this plane was 6.5 mm (2-17 mm). CONCLUSIONS: The para-midline approach for lumbar surgery is associated with less blood loss than traditional, subperiosteal exposure techniques. The fatty interval through which this approach is made is universally present and identifiable on MRI. The authors offer this approach as a means of decreasing the risks associated with blood loss and transfusion with posterior lumbar surgery.

Does surgical timing influence functional recovery after lumbar discectomy? A systematic review.

BACKGROUND: The impact of the duration of preoperative symptoms on outcomes after lumbar discectomy has not been sufficiently answered in a single study but is a potentially important clinical variable. QUESTIONS/PURPOSES: A systematic review was performed to answer two questions: (1) Does symptomatic duration before surgery influence functional recovery after lumbar discectomy? (2) What is the time point for intervention beyond which the extent of postoperative recovery might be compromised? METHODS: The systematic review began with a query of PubMed using a structured algorithm comprised of medical subject heading terms. This was supplemented by a keyword search in PubMed along with queries of Embase, Scopus, and Web of Science and searches of reference lists as well as the tables of contents of relevant journals. Eligible studies were those that evaluated aspects of recovery after elective discectomy and stratified duration of symptoms before surgery. Included papers were abstracted by two authors and determinations regarding the period of symptom duration and its impact on outcome were recorded. Eleven studies met all inclusion criteria. No prospectively randomized trials addressed our study questions. RESULTS: Nine of 11 studies, four of which were prospective, maintained that longer symptom duration adversely impacted postsurgical recovery. There were substantial differences among the critical periods of symptom duration reported by individual studies, which ranged from 2 to 12 months. A preponderance of studies (five of nine) reported that surgical interventions could be performed at periods of 6 months or greater without impacting recovery. CONCLUSIONS: Longer symptom duration had an adverse impact on results in most studies after lumbar discectomy. A possible point beyond which outcomes may be compromised is 6 months after symptom onset. Limitations in the literature surveyed, however, prevent firm conclusions.