Area Socioeconomic Status is Associated with Refusal of Recommended Surgery in Patients with Metastatic Bone and Joint Disease.

BACKGROUND: This study sought to identify associations between the Yost Index, a geocoded area neighborhood socioeconomic status (nSES) score, and race/ethnicity with patient refusal of recommended surgery for metastatic bone disease. METHODS: Patients with metastatic bone disease were extracted from the Surveillance, Epidemiology, and End Results database. The Yost Index was geocoded using factor analysis and categorized into quintiles using census tract-level American Community Service (ACS) 5-year estimates and seven nSES measures. Multivariable logistic regression models calculated odds ratios (ORs) of refusal of recommended surgery and 95% confidence intervals (CIs), adjusting for clinical covariates. RESULTS: A total of 138,257 patients were included, of which 14,943 (10.8%) were recommended for surgical resection. Patients in the lowest nSES quintile had 57% higher odds of refusing surgical treatment than those in the highest quintile (aOR = 1.57, 95% CI 1.30-1.91, p < 0.001). Patients in the lowest nSES quintile also had a 31.2% higher age-adjusted incidence rate of not being recommended for surgery compared with those in the highest quintile (186.4 vs. 142.1 per 1 million, p < 0.001). Black patients had 34% higher odds of refusing treatment compared with White patients (aOR = 1.34, 95% CI 1.14-1.58, p = 0.003). Advanced age, unmarried status, and patients with aggressive cancer subtypes were associated with higher odds of refusing surgery (p < 0.001). CONCLUSIONS: nSES and race/ethnicity are independent predictors of a patient refusing surgery for metastatic cancer to bone, even after adjusting for various clinical covariates. Effective strategies for addressing these inequalities and improving the access and quality of care of patients with a lower nSES and minority backgrounds are needed.

Projections of Single-level and Multilevel Spinal Instrumentation Procedure Volume and Associated Costs for Medicare Patients to 2050.

BACKGROUND: Instrumented spinal fusions can be used in the treatment of vertebral fractures, spinal instability, and scoliosis or kyphosis. Construct-level selection has notable implications on postoperative recovery, alignment, and mobility. This study sought to project future trends in the implementation rates and associated costs of single-level versus multilevel instrumentation procedures in US Medicare patients aged older than 65 years in the United States. METHODS: Data were acquired from the Centers for Medicare & Medicaid Services from January 1, 2000, to December 31, 2019. Procedure costs and counts were abstracted using Current Procedural Terminology codes to identify spinal level involvement. The Prophet machine learning algorithm was used, using a Bayesian Inference framework, to generate point forecasts for 2020 to 2050 and 95% forecast intervals (FIs). Sensitivity analyses were done by comparing projections from linear, log-linear, Poisson and negative-binomial, and autoregressive integrated moving average models. Costs were adjusted for inflation using the 2019 US Bureau of Labor Statistics' Consumer Price Index. RESULTS: Between 2000 and 2019, the annual spinal instrumentation volume increased by 776% (from 7,342 to 64,350 cases) for single level, by 329% (from 20,319 to 87,253 cases) for two-four levels, by 1049% (from 1,218 to 14,000 cases) for five-seven levels, and by 739% (from 193 to 1,620 cases) for eight-twelve levels (P < 0.0001). The inflation-adjusted reimbursement for single-level instrumentation procedures decreased 45.6% from $1,148.15 to $788.62 between 2000 and 2019, which is markedly lower than for other prevalent orthopaedic procedures: total shoulder arthroplasty (-23.1%), total hip arthroplasty (-39.2%), and total knee arthroplasty (-42.4%). By 2050, the number of single-level spinal instrumentation procedures performed yearly is projected to be 124,061 (95% FI, 87,027 to 142,907), with associated costs of $93,900,672 (95% FI, $80,281,788 to $108,220,932). CONCLUSIONS: The number of single-level instrumentation procedures is projected to double by 2050, while the number of two-four level procedures will double by 2040. These projections offer a measurable basis for resource allocation and procedural distribution.

Disparities in postoperative complications and perioperative events based on insurance status following elective spine surgery: A systematic review and meta-analysis.

Background: Increasing evidence demonstrates disparities among patients with differing insurance statuses in the field of spine surgery. However, no pooled analyses have performed a robust review characterizing differences in postoperative outcomes among patients with varying insurance types. Methods: A comprehensive literature search of the PUBMED, MEDLINE(R), ERIC, and EMBASE was performed for studies comparing postoperative outcomes in patients with private insurance versus government insurance. Pooled incidence rates and odds ratios were calculated for each outcome and meta-analyses were conducted for 3 perioperative events and 2 types of complications. In addition to pooled analysis, sub-analyses were performed for each outcome in specific government payer statuses. Results: Thirty-eight studies (5,018,165 total patients) were included. Compared with patients with private insurance, patients with government insurance experienced greater risk of 90-day re-admission (OR 1.84, p<.0001), non-routine discharge (OR 4.40, p<.0001), extended LOS (OR 1.82, p<.0001), any postoperative complication (OR 1.61, p<.0001), and any medical complication (OR 1.93, p<.0001). These differences persisted across outcomes in sub-analyses comparing Medicare or Medicaid to private insurance. Similarly, across all examined outcomes, Medicare patients had a higher risk of experiencing an adverse event compared with non-Medicare patients. Compared with Medicaid patients, Medicare patients were only more likely to experience non-routine discharge (OR 2.68, p=.0007). Conclusions: Patients with government insurance experience greater likelihood of morbidity across several perioperative outcomes. Additionally, Medicare patients fare worse than non-Medicare patients across outcomes, potentially due to age-based discrimination. Based on these results, it is clear that directed measures should be taken to ensure that underinsured patients receive equal access to resources and quality care.

External Validation of an Online Wound Infection and Wound Reoperation Risk Calculator After Metastatic Spinal Tumor Surgery.

STUDY DESIGN: This was a single-institutional retrospective cohort study. OBJECTIVE: Wound infections are common following spine metastasis surgery and can result in unplanned reoperations. A recent study published an online wound complication risk calculator but has not yet undergone external validation. Our aim was to evaluate the accuracy of this risk calculator in predicting 30-day wound infections and 30-day wound reoperations using our operative spine metastasis population. METHODS: An internal operative database was used to identify patients between 2012 and 2022. The primary outcomes were 1) any surgical site infection and 2) wound-related revision surgery within 30 days following surgery. Patient details were manually collected from electronic medical records and entered into the calculator to determine predicted complication risk percentages. Predicted risks were compared to observed outcomes using receiver operator characteristic (ROC) curves with areas under the curve (AUC). RESULTS: A total of 153 patients were included. The observed 30-day postoperative wound infection incidence was 5% while the predicted wound infection incidence was 6%. In ROC analysis, good discrimination was found for the wound infection model (AUC = 0.737; P = 0.024). The observed wound reoperation rate was 5% and the predicted wound reoperation rate was 6%. ROC analysis demonstrated poor discrimination for wound reoperations (AUC = 0.559; P = 0.597). CONCLUSIONS: The online wound-related risk calculator was found to accurately predict wound infections but not wound reoperations within our metastatic spine surgery cohort. We suggest that the model may be clinically useful despite underlying population differences, but further work must be done to generate and validate accurate prediction tools.

Association of Socioeconomic Status With Worse Overall Survival in Patients With Bone and Joint Cancer.

BACKGROUND: The effect of socioeconomic status (SES) on the outcomes of patients with metastatic cancer to bone has not been adequately studied. We analyzed the association between the Yost Index, a composite geocoded SES score, and overall survival among patients who underwent nonprimary surgical resection for bone metastases. METHODS: This population-based study used data from the National Cancer Institute's Surveillance, Epidemiology, and End Results database (2010 to 2018). We categorized bone and joint sites using International Classification of Disease-O-3 recodes. The Yost Index was geocoded using a factor analysis and categorized into quintiles using census tract-level American Community Service 5-year estimates and seven measures: median household income, median house value, median rent, percent below 150% of the poverty line, education index, percent working class, and percent unemployed. Multivariate Cox regression models were used to calculate adjusted hazard ratios of overall survival and 95% confidence intervals. RESULTS: A total of 138,158 patients were included. Patients with the lowest SES had 34% higher risk of mortality compared with those with the highest SES (adjusted hazard ratio of 1.34, 95% confidence interval: 1.32 to 1.37, P < 0.001). Among patients who underwent nonprimary surgery of the distant bone tumor (n = 11,984), the age-adjusted mortality rate was 31.3% higher in the lowest SES patients compared with the highest SES patients (9.9 versus 6.8 per 100,000, P < 0.001). Patients in the lowest SES group showed more racial heterogeneity (63.0% White, 33.5% Black, 3.1% AAPI) compared with the highest SES group (83.9% White, 4.0% Black, 11.8% AAPI, P < 0.001). Higher SES patients are more likely to be married (77.5% versus 59.0%, P < 0.0001) and to live in metropolitan areas (99.6% versus 73.6%, P < 0.0001) compared with lower SES patients. DISCUSSION: Our results may have implications for developing interventions to improve access and quality of care for patients from lower SES backgrounds, ultimately reducing disparities in orthopaedic surgery.

Racial Differences in Perioperative Complications, Readmissions, and Mortalities After Elective Spine Surgery in the United States: A Systematic Review Using AI-Assisted Bibliometric Analysis.

STUDY DESIGN: Systematic Review and Meta-analysis. OBJECTIVES: To evaluate the impact of race on post-operative outcomes and complications following elective spine surgery in the United States. METHODS: PUBMED, MEDLINE(R), ERIC, EMBASE, and SCOPUS were searched for studies documenting peri-operative events for White and African American (AA) patients following elective spine surgery. Pooled odds ratios were calculated for each 90-day outcome and meta-analyses were performed for 4 peri-operative events and 7 complication categories. Sub-analyses were performed for each outcome on single institution (SI) studies and works that included <100,000 patients. RESULTS: 53 studies (5,589,069 patients, 9.8% AA) were included. Eleven included >100,000 patients. AA patients had increased rates of 90-day readmission (OR 1.33, P = .0001), non-routine discharge (OR 1.71, P = .0001), and mortality (OR 1.66, P = .0003), but not re-operation (OR 1.16, P = .1354). AA patients were more likely to have wound-related complications (OR 1.47, P = .0001) or medical complications (OR 1.35, P = .0006), specifically cardiovascular (OR 1.33, P = .0126), deep vein thrombosis/pulmonary embolism (DVT/PE) (OR 2.22, P = .0188) and genitourinary events (OR 1.17, P = .0343). SI studies could only detect racial differences in re-admissions and non-routine discharges. Studies with <100,000 patients replicated the above findings but found no differences in cardiovascular complications. Disparities in mortality were only detected when all studies were included. CONCLUSIONS: AA patients faced a greater risk of morbidity across several distinct categories of peri-operative events. SI studies can be underpowered to detect more granular complication types (genitourinary, DVT/PE). Rare events, such as mortality, require larger sample sizes to identify significant racial disparities.

The prognostic role of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and systemic immune-inflammation index on short- and long-term outcome following surgery for spinal metastases.

OBJECTIVE: Inflammatory markers such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) have shown promise in predicting mortality in various types of cancer. The purpose of this study was to assess NLR, PLR, and SII in predicting 30-day mortality and overall survival (OS) among surgically treated patients with spinal metastasis. METHODS: This was a retrospective study including 153 patients who underwent surgery for spinal metastasis between 2012 and 2022. Electronic medical records were manually reviewed, and NLR, PLR, and SII were calculated from preoperative neutrophil, platelet, and lymphocyte counts. Receiver operating characteristic curves with areas under the curve were generated to determine cutoff values. Logistic regression was used to determine the odds ratios (ORs) for 30-day mortality. The Kaplan-Meier method and Cox regression were used to determine the hazard ratio (HR) for OS limited to 5 years postoperatively. RESULTS: Preoperative cutoff values were as follows: NLR > 10.2, PLR > 260, and SII > 2900. Overall, 35.9% (55/153) of patients had elevated NLR, 45.7% (70/153) had elevated PLR, and 30.7% (47/153) had elevated SII. The overall 30-day mortality was 8.5% (13/153). After controlling for confounders such as performance status and primary tumor type, high NLR (OR 5.20, 95% CI 1.21-22.28; p = 0.026) and SII (OR 4.92, 95% CI 1.17-20.63; p = 0.029) were associated with increased odds of 30-day postoperative mortality. The median OS time in the study population was 26 months (95% CI 12-40 months). After controlling for confounders such as Eastern Cooperative Oncology Group status, primary tumor, and hypoalbuminemia, high NLR was associated with shorter OS (HR 2.23, 95% CI 1.48-3.97; p = 0.003). CONCLUSIONS: High preoperative NLR and SII were independently associated with 30-day postoperative mortality in this study. Elevated NLR was also found to be associated with shorter OS. The prognostic role of these metrics warrants further investigation.

The prognostic nutritional index (PNI) is independently associated with 90-day and 12-month mortality after metastatic spinal tumor surgery.

INTRODUCTION: Estimated postoperative survival is an important consideration during the decision-making process for patients with spinal metastases. Nutritional status has been associated with poor outcomes and limited survival in the general cancer population. The objective of this study was to evaluate the predictive utility of the prognostic nutritional index (PNI) for postoperative mortality after spinal metastasis surgery. METHODS: A total of 139 patients who underwent oncologic surgery for spinal metastases between April 2012 and August 2022 and had a minimum 90-day follow-up were included. PNI was calculated using preoperative serum albumin and total lymphocyte count, with PNI < 40 defined as low. The mean PNI of our cohort was 43 (standard deviation: 7.7). The primary endpoint was 90-day mortality, and the secondary endpoint was 12-month mortality. Multivariate logistic regression analyses were performed. RESULTS: The 90-day mortality was 27% (37/139), and the 12-month mortality was 56% (51/91). After controlling for age, ECOG performance status, total psoas muscle cross-sectional area (TPA), and primary cancer site, the PNI was associated with 90-day mortality [odds ratio 0.86 (95% confidence interval 0.79-0.94); p = 0.001]. After controlling for ECOG performance status and primary cancer site, the PNI was associated with 12-month mortality [OR 0.89 (95% CI 0.82-0.97); p = 0.008]. Patients with a low PNI had a 50% mortality rate at 90 days and an 84% mortality rate at 12 months. CONCLUSION: The PNI was independently associated with 90-day and 12-month mortality after metastatic spinal tumor surgery, independent of performance status, TPA, and primary cancer site.

Artificial Intelligence in Modern Orthopaedics: Current and Future Applications.

➢: With increasing computing power, artificial intelligence (AI) has gained traction in all aspects of health care delivery. Orthopaedics is no exception because the influence of AI technology has become intricately linked with its advancement as evidenced by increasing interest and research. ➢: This review is written for the orthopaedic surgeon to develop a better understanding of the main clinical applications and potential benefits of AI within their day-to-day practice. ➢: A brief and easy-to-understand foundation for what AI is and the different terminology used within the literature is first provided, followed by a summary of the newest research on AI applications demonstrating increased accuracy and convenience in risk stratification, clinical decision-making support, and robotically assisted surgery.

Do racial disparities exist in a spine surgery practice that serves a predominately minority population? Outcomes of transforaminal lumbar interbody fusion: A retrospective review.

Background: Racial minority status is associated with inferior peri-operative outcomes following spinal fusion. Findings have largely been reported within institutions serving few minority patients. This study aimed to identify if racial disparities exist for transforaminal lumbar interbody fusion (TLIF) procedures within an urban academic medical center which serves a majority non-White population. Methods: This is a retrospective review of patients who underwent a TLIF procedure at our institution between 06/2016-10/2019. Primary outcome measures included length of stay (LOS), discharge disposition, 30-day return to the emergency department (ED), 30-day readmission rate, and 30-day complication rates. One-hundred-fifty-six patients (female: male, 99: 57) met inclusion criteria. Demographic and clinical data (body mass index (BMI), comorbidities, preoperative lab values) were compared. Results: The mean LOS was 6.2, 5.9, and 6 days in the White, Hispanic, and Black cohorts, respectively (p = 0.92). There were no differences in discharge disposition between groups (p = 0.52). Thirty-day post-operative complication rates did not differ between groups (p > 0.07). Readmission rates did not differ between groups (p > 0.05). ED visits were more prevalent in the Hispanic group with 16 visits as compared to 8 and 4 in the White and Black groups respectively (p = 0.01). Conclusions: We found no racial disparities in terms of LOS, discharge disposition, or 30-day readmission rates. Hispanic patients demonstrated an increased utilization of the ED in the early post-operative period. Efforts to overcome language barriers, communicate instructions clearly, and outline post-operative expectations and plans may prevent the need for post-operative ED visits.

Is the Use of Intraoperative 3D Navigation for Thoracolumbar Spine Surgery a Risk Factor for Post-Operative Infection?

Pedicle screw fixation is a technique used to provide rigid fixation in thoracolumbar spine surgery. Safe intraosseous placement of pedicle screws is necessary to provide optimal fixation as well as to avoid damage to adjacent anatomic structures. Despite the wide variety of techniques available, none thus far has been able to fully eliminate the risk of malpositioned screws. Intraoperative 3-dimensional navigation (I3DN) was developed to improve accuracy in the placement of pedicle screws. To our knowledge, no previous studies have investigated whether infection rates are higher with I3DN. A single-institution, retrospective study of patients age > 18 undergoing thoracolumbar fusion and instrumentation was carried out and use of I3DN was recorded. The I3DN group had a significantly greater rate of return to the operating room for culture-positive incision and drainage (17 (4.1%) vs. 1 (0.6%), p = 0.025). In multivariate analysis, the use of I3DM did not reach significance with an OR of 6.49 (0.84−50.02, p = 0.073). Post-operative infections are multifactorial and potential infection risks associated with I3DN need to be weighed against the safety benefits of improved accuracy of pedicle screw positioning.

Sarcopenia Is an Independent Risk Factor for Proximal Junctional Disease Following Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: Sarcopenia is a risk factor for medical complications following spine surgery. However, the role of sarcopenia as a risk factor for proximal junctional disease (PJD) remains undefined. This study evaluates whether sarcopenia is an independent predictor of proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) following adult spinal deformity (ASD) surgery. METHODS: ASD patients who underwent thoracic spine to pelvis fusion with 2-year clinical and radiographic follow-up were reviewed for development of PJK and PJD. Average psoas cross-sectional area on preoperative axial computed tomography or magnetic resonance imaging at L4 was recorded. Previously described PJD risk factors were assessed for each patient, and multivariate linear regression was performed to identify independent risk factors for PJK and PJF. Disease-specific thresholds were calculated for sarcopenia based on psoas cross-sectional area. RESULTS: Of 32 patients, PJK and PJF occurred in 20 (62.5%) and 12 (37.5%), respectively. Multivariate analysis demonstrated psoas cross-sectional area to be the most powerful independent predictor of PJK (P = .02) and PJF (P = .009). Setting ASD disease-specific psoas cross-sectional area thresholds of <12 cm2 in men and <8 cm2 in women resulted in a PJF rate of 69.2% for patients below these thresholds, relative to 15.8% for those above the thresholds. CONCLUSIONS: Sarcopenia is an independent, modifiable predictor of PJK and PJF, and is easily assessed on standard preoperative computed tomography or magnetic resonance imaging. Surgeons should include sarcopenia in preoperative risk assessment and consider added measures to avoid PJF in sarcopenic patients.

Efficacy, Cost, and Complications of Demineralized Bone Matrix in Instrumented Lumbar Fusion: Comparison With rhBMP-2.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To evaluate demineralized bone matrix as an adjunct for instrumented lumbar spine fusion compared with recombinant human bone morphogenetic protein-2 (rhBMP-2). METHODS: Clinical and radiographic review was performed of 43 patients with degenerative spine disease treated with posterolateral spinal fusion with or without posterior or transforaminal lumbar interbody fusion. Final analysis included sixteen patients treated with demineralized bone matrix (DBM; Accell Evo3, SeaSpine) compared with a retrospective matched group of 21 patients treated with rhBMP-2 (rhBMP-2, Infuse, Medtronic). All patients were followed for 24 months. Fusion was evaluated by computed tomography and/or x-ray. Clinical outcomes included visual analogue scale (VAS), Oswestry Disability Index (ODI), and Short Form 12 (SF-12). RESULTS: Overall fusion rate, including posterolateral and/or interbody fusion, was 100% for both groups, though the fusion rates in the posterolateral space alone were 93.5% and 100% for the DBM and rhBMP-2 groups, respectively. Clinical outcomes were similar between groups, with the DBM group showing greater improvement in ODI. The rhBMP-2 group showed higher rates of radiographic complications with 7 of 21 patients (33.3%) demonstrating either adjacent level fusion or ectopic bone formation, compared with zero in the DBM group. Average biologic cost per level was $1522 for DBM and $3505 for rhBMP-2. CONCLUSIONS: DBM and rhBMP-2 demonstrated similar radiographic and clinical outcomes in instrumented lumbar fusions. rhBMP-2 was associated with higher rates of radiographic complications and significantly higher costs.

Surgical Site Infection as a Risk Factor for Long-Term Instrumentation Failure in Patients with Spinal Deformity: A Retrospective Cohort Study.

BACKGROUND: Surgical site infection (SSI) remains a complication of spine deformity surgery. Although fusion/instrumentation failure in the setting of SSI has been reported, few studies have investigated the relationship between these entities. We examine the relationship between early SSI and fusion/instrumentation failure after instrumented fusion in patients with thoracolumbar scoliosis. METHODS: A retrospective review of a prospectively maintained case series for patients undergoing spine surgery between January 1, 2006, and October 3, 2017. Inclusion criteria included age ≥18 years and surgery performed for correction of thoracolumbar scoliosis. Data collected included various demographic, clinical, and operative variables. RESULTS: 532 patients met inclusion criteria, with 20 (4%) experiencing SSI. Diabetes mellitus was the only demographic risk factor for increased SSI (P = 0.026). Number of fused levels, blood volume loss, and operative time were similar between groups. Fusion/instrumentation failure occurred in 68 (13%) patients, 10 of whom (15%) had SSI, whereas of the 464 patients with no fusion/instrumentation failure, only 10 (2%) had SSI (P < 0.001). Of the 20 patients with SSI, 10 (50%) had fusion/instrumentation failure, whereas in the 512 patients with no infection, only 58 (11%) had fusion/instrumentation failure (P < 0.001). Patients with infection also experienced significantly shorter time to fusion/instrumentation failure (P = 0.025), higher need for revision surgery (P < 0.001), and shorter time to revision surgery (P = 0.012). CONCLUSIONS: Early SSI significantly increases the risk of fusion/instrumentation failure in patients with thoracolumbar scoliotic deformity, and it significantly shortens the time to failure. Patients with early SSI have a significantly higher likelihood of requiring revision surgery and after a significantly shorter time interval.

Real-World Effectiveness of Physical Therapy for Common Neck Pain Diagnoses: A Multivariate Analysis of 1554 Patients.

STUDY DESIGN: Retrospective cohort study (Level of evidence-3). OBJECTIVE: The objective of this study was to investigate the real-life effectiveness of physical therapy (PT) for patients initially presenting with common neck pain diagnoses. SUMMARY OF BACKGROUND DATA: Neck pain is a common cause of morbidity and a leading cause of disability in the United States. PT is prescribed as a first-line treatment for the vast majority of patients with neck pain; however, there is limited literature supporting the effectiveness of these treatments. METHODS: A total of 1554 patients enrolled in PT for the nonoperative treatment of neck pain were included in the study. Three primary patient-reported outcome (PRO) measures [neck disability index (NDI), resting numeric pain rating scale (NPRS), and activity NPRS] were recorded before and at conclusion of therapy. Improvement was noted if patients met a threshold value for a minimal clinically important difference (MCID). Bivariate analysis using a χ test and multiple logistic regression analysis were performed to determine risk factors predictive of treatment failure. RESULTS: About 40.5% of patients achieved MCID for NDI with an average change of -6.31 points. For resting NPRS and activity NPRS scores, 50.6% and 52.1% of patients achieved MCID with an average change of -1.93 and -2.36, respectively. After multiple logistic regression analysis, worker's compensation status was found to be an independent predictor for treatment failure in all groups; whereas, Medicare status was found predictive of achieving MCID in the activity NPRS group. CONCLUSIONS: We observed that up to half of the patients analyzed met the minimum criteria for improvement in neck pain with respect to the PRO measures, suggesting that real-life effectiveness of PT for common neck pain diagnoses may approach 50%.

Contribution of facet joints, axial compression, and composition to human lumbar disc torsion mechanics.

Stresses applied to the spinal column are distributed between the intervertebral disc and facet joints. Structural and compositional changes alter stress distributions within the disc and between the disc and facet joints. These changes influence the mechanical properties of the disc joint, including its stiffness, range of motion, and energy absorption under quasi-static and dynamic loads. There have been few studies evaluating the role of facet joints in torsion. Furthermore, the relationship between biochemical composition and torsion mechanics is not well understood. Therefore, the first objective of this study was to investigate the role of facet joints in torsion mechanics of healthy and degenerated human lumbar discs under a wide range of compressive preloads. To achieve this, each disc was tested under four different compressive preloads (300-1200 N) with and without facet joints. The second objective was to develop a quantitative structure-function relationship between tissue composition and torsion mechanics. Facet joints have a significant contribution to disc torsional stiffness (∼60%) and viscoelasticity, regardless of the magnitude of axial compression. The findings from this study demonstrate that annulus fibrosus GAG content plays an important role in disc torsion mechanics. A decrease in GAG content with degeneration reduced torsion mechanics by more than an order of magnitude, while collagen content did not significantly influence disc torsion mechanics. The biochemical-mechanical and compression-torsion relationships reported in this study allow for better comparison between studies that use discs of varying levels of degeneration or testing protocols and provide important design criteria for biological repair strategies. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Evaluating the Cavus Foot.

The cavus foot is a deformity characterized by abnormal elevation of the medial arch of the foot. Unique among foot deformities, cavus typically occurs secondary to a spinal cord or neuromuscular pathology, with two-thirds of patients having an underlying neurologic diagnosis. Thus, recognition of cavus foot and appropriate evaluation are essential in the primary care setting. Patients may present with unstable gait, frequent ankle sprains, or pain along the metatarsal heads or the lateral border of the foot. The diagnosis can be confirmed with a lateral weight-bearing radiograph, with several key measurements defining a pes cavus alignment. A thorough history and physical examination should be performed to look for possible secondary causes. The first step in the treatment of cavus deformity is to address the underlying cause. After that, a variety of treatment options are available to alleviate the pain and dysfunction caused by this deformity. [Pediatr Ann. 2016;45(6):e218-e222.].

How Effective is Physical Therapy for Common Low Back Pain Diagnoses?: A Multivariate Analysis of 4597 Patients.

STUDY DESIGN: A retrospective review. OBJECTIVE: The aim of this study is to evaluate whether the treatment of low back pain with physical therapy results in clinically significant improvements in patient-reported pain and functional outcomes. SUMMARY OF BACKGROUND DATA: Low back pain is a major cause of morbidity and disability in health care. Previous studies have found poor efficacy for surgery in the absence of specific indications. A variety of nonoperative treatments are available; however, there is scant evidence to guide the practitioner as to the efficacy of these treatments. METHODS: Four thousand five hundred ninety-seven patients who underwent physical therapy for the nonoperative treatment of low back pain were included. The primary outcome measures were pre-and post-treatment scores on the Oswestry Disability Index (ODI), Numeric Pain Rating Scale (NPRS) during activity, and NPRS during rest. Previously published thresholds for minimal clinically important difference (MCID) were used to determine the proportion of patients meeting MCID for each of our outcomes. Patients with starting values below the MCID for each variable were excluded from analysis. Logistic regression analysis was used to determine patient risk factors predictive of treatment failure. RESULTS: About 28.5% of patients met the MCID for improvement in ODI. Presence of night symptoms, obesity, and smoking were predictors of treatment failure for ODI. Fifty-nine percent of patients met the MCID for improvement in resting NPRS, with a history of venous thromboembolism, night symptoms, psychiatric disease, workers' compensation status, smoking, and obesity predictive of treatment failure. Sixty percent of patients met the MCID for improvement in activity NPRS, with night symptoms, workers' compensation status, and smoking predictive of treatment failure. CONCLUSION: We observed that a substantial percentage of the population did not meet MCID for pain and function following treatment of low back pain with physical therapy. Common risk factors for treatment failure included smoking and presence of night symptoms. LEVEL OF EVIDENCE: 4.

Number of recent inpatient admissions as a risk factor for increased complications, length of stay, and cost in patients undergoing posterior lumbar fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To identify risk factors for increased complication rate, hospital charges, and length of stay in patients undergoing posterior lumbar fusion. SUMMARY OF BACKGROUND DATA: A better understanding of risk factors for perioperative complications in patients undergoing posterior lumbar fusion can aid with patient selection and postoperative monitoring. Previous studies have assessed the impact of factors such as body mass index, age, and American Society of Anesthesiologists physical status classification on complication rate. METHODS: Data were acquired from the institution's quality improvement data set. Preoperative demographic factors included sex, age, number of inpatient admissions in the prior year, body mass index, Charlson comorbidity score, American Society of Anesthesiologists physical status classification, number of levels fused, operative duration, and medications on admission. Complications recorded included pneumonia, myocardial infarction, venous thromboembolic event, hardware failure, readmission, or unplanned return to the operating room. Multivariate regression was used to identify predictors of increased complication rate, hospital charges, and length of stay. RESULTS: A total of 462 patients were included. A history of more than 1 admission in the prior year was the only variable significantly associated with increased complication rate (odds ratio 10.56, P < 0.0001). History of more than 1 admission in the prior year (+1.92 d, P < 0.0001), operative duration more than 5 hours (+0.81 d, P = 0.008), and American Society of Anesthesiologists physical status classification 3 or greater (+0.75 d, P = 0.01) were associated with increased length of stay, whereas history of more than 1 admission in the prior year (+$27,798, P < 0.0001), fusion of 4 or more levels (+$38,043, P < 0.0001), and operative duration more than 5 hours (+$40,298, P < 0.0001) were associated with increased total charges. CONCLUSION: The number of inpatient admissions in the prior year was found to be a more powerful predictor of perioperative risk after lumbar fusion than metrics evaluated in prior studies, such as age, body mass index, and comorbidities. LEVEL OF EVIDENCE: 3.

Apoptosis resistance and PKC signaling: distinguishing features of high and low metastatic cells.

The complexity of the process of metastasis is widely recognized. We report herein on a recurrent feature of high compared to low metastatic cells that is linked to their ability to survive early after their arrival at secondary sites. Using novel fluorescent-based imaging strategies that assess tumor cell interaction with the lung microenvironment, we have determined that most high and low metastatic cells can be distinguished within 6 hours of their arrival in the lung and further that this difference is defined by the ability of high metastatic cells to resist apoptosis at the secondary site. Despite the complexity of the metastatic cascade, the performance of cells during this critical window is highly defining of their metastatic proclivity. To explore mechanisms, we next evaluated biochemical pathways that may be linked to this survival phenotype in highly metastatic cells. Interestingly, we found no association between the Akt survival pathway and this metastatic phenotype. Of all pathways examined, only protein kinase C (PKC) activation was significantly linked to survival of highly metastatic cells. These data provide a conceptual understanding of a defining difference between high and low metastatic cells. The connection to PKC activation may provide a biologic rationale for the use of PKC inhibition in the prevention of metastatic progression.