Is the Centers for Medicare and Medicaid Services Hierarchical Condition Category Risk Adjustment Model Satisfactory for Quantifying Risk After Spine Surgery?

BACKGROUND: The Centers for Medicare and Medicaid Services (CMS) hierarchical condition category (HCC) coding is a risk adjustment model that allows for the estimation of risk-and cost-associated with health care provision. Current models may not include key factors that fully delineate the risk associated with spine surgery. OBJECTIVE: To augment CMS HCC risk adjustment methodology with socioeconomic data to improve its predictive capabilities for spine surgery. METHODS: The National Inpatient Sample was queried for spinal fusion, and the data was merged with county-level coverage and socioeconomic status variables obtained from the Brookings Institute. We predicted outcomes (death, nonroutine discharge, length of stay [LOS], total charges, and perioperative complication) with pairs of hierarchical, mixed effects logistic regression models-one using CMS HCC score alone and another augmenting CMS HCC scores with demographic and socioeconomic status variables. Models were compared using receiver operating characteristic curves. Variable importance was assessed in conjunction with Wald testing for model optimization. RESULTS: We analyzed 653 815 patients. Expanded models outperformed models using CMS HCC score alone for mortality, nonroutine discharge, LOS, total charges, and complications. For expanded models, variable importance analyses demonstrated that CMS HCC score was of chief importance for models of mortality, LOS, total charges, and complications. For the model of nonroutine discharge, age was the most important variable. For the model of total charges, unemployment rate was nearly as important as CMS HCC score. CONCLUSION: The addition of key demographic and socioeconomic characteristics substantially improves the CMS HCC risk-adjustment models when modeling spinal fusion outcomes. This finding may have important implications for payers, hospitals, and policymakers.

Do social determinants of health impact access to neurosurgical care in the United States? A workforce perspective.

OBJECTIVE: This study attempts to use neurosurgical workforce distribution to uncover the social determinants of health that are associated with disparate access to neurosurgical care. METHODS: Data were compiled from public sources and aggregated at the county level. Socioeconomic data were provided by the Brookings Institute. Racial and ethnicity data were gathered from the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research. Physician density was retrieved from the Health Resources and Services Administration Area Health Resources Files. Catchment areas were constructed based on the 628 counties with neurosurgical coverage, with counties lacking neurosurgical coverage being integrated with the nearest covered county based on distances from the National Bureau of Economic Research's County Distance Database. Catchment areas form a mutually exclusive and collectively exhaustive breakdown of the entire US population and licensed neurosurgeons. Socioeconomic factors, race, and ethnicity were chosen as independent variables for analysis. Characteristics for each catchment area were calculated as the population-weighted average across all contained counties. Linear regression analysis modeled two outcomes of interest: neurosurgeon density per capita and average distance to neurosurgical care. Coefficient estimates (CEs) and 95% confidence intervals were calculated and scaled by 1 SD to allow for comparison between variables. RESULTS: Catchment areas with higher poverty (CE = 0.64, 95% CI 0.34-0.93) and higher prime age employment (CE = 0.58, 95% CI 0.40-0.76) were significantly associated with greater neurosurgeon density. Among categories of race and ethnicity, catchment areas with higher proportions of Black residents (CE = 0.21, 95% CI 0.06-0.35) were associated with greater neurosurgeon density. Meanwhile, catchment areas with higher proportions of Hispanic residents displayed lower neurosurgeon density (CE = -0.17, 95% CI -0.30 to -0.03). Residents of catchment areas with higher housing vacancy rates (CE = 2.37, 95% CI 1.31-3.43), higher proportions of Native American residents (CE = 4.97, 95% CI 3.99-5.95), and higher proportions of Hispanic residents (CE = 2.31, 95% CI 1.26-3.37) must travel farther, on average, to receive neurosurgical care, whereas people living in areas with a lower income (CE = -2.28, 95% CI -4.48 to -0.09) or higher proportion of Black residents (CE = -3.81, 95% CI -4.93 to -2.68) travel a shorter distance. CONCLUSIONS: Multiple factors demonstrate a significant correlation with neurosurgical workforce distribution in the US, most notably with Hispanic and Native American populations being associated with greater distances to care. Additionally, higher proportions of Hispanic residents correlated with fewer neurosurgeons per capita. These findings highlight the interwoven associations among socioeconomics, race, ethnicity, and access to neurosurgical care nationwide.

Decision tree-based machine learning analysis of intraoperative vasopressor use to optimize neurological improvement in acute spinal cord injury.

OBJECTIVE: Previous work has shown that maintaining mean arterial pressures (MAPs) between 76 and 104 mm Hg intraoperatively is associated with improved neurological function at discharge in patients with acute spinal cord injury (SCI). However, whether temporary fluctuations in MAPs outside of this range can be tolerated without impairment of recovery is unknown. This retrospective study builds on previous work by implementing machine learning to derive clinically actionable thresholds for intraoperative MAP management guided by neurological outcomes. METHODS: Seventy-four surgically treated patients were retrospectively analyzed as part of a longitudinal study assessing outcomes following SCI. Each patient underwent intraoperative hemodynamic monitoring with recordings at 5-minute intervals for a cumulative 28,594 minutes, resulting in 5718 unique data points for each parameter. The type of vasopressor used, dose, drug-related complications, average intraoperative MAP, and time spent in an extreme MAP range (< 76 mm Hg or > 104 mm Hg) were collected. Outcomes were evaluated by measuring the change in American Spinal Injury Association Impairment Scale (AIS) grade over the course of acute hospitalization. Features most predictive of an improvement in AIS grade were determined statistically by generating random forests with 10,000 iterations. Recursive partitioning was used to establish clinically intuitive thresholds for the top features. RESULTS: At discharge, a significant improvement in AIS grade was noted by an average of 0.71 levels (p = 0.002). The hemodynamic parameters most important in predicting improvement were the amount of time intraoperative MAPs were in extreme ranges and the average intraoperative MAP. Patients with average intraoperative MAPs between 80 and 96 mm Hg throughout surgery had improved AIS grades at discharge. All patients with average intraoperative MAP > 96.3 mm Hg had no improvement. A threshold of 93 minutes spent in an extreme MAP range was identified after which the chance of neurological improvement significantly declined. Finally, the use of dopamine as compared to norepinephrine was associated with higher rates of significant cardiovascular complications (50% vs 25%, p < 0.001). CONCLUSIONS: An average intraoperative MAP value between 80 and 96 mm Hg was associated with improved outcome, corroborating previous results and supporting the clinical verifiability of the model. Additionally, an accumulated time of 93 minutes or longer outside of the MAP range of 76-104 mm Hg is associated with worse neurological function at discharge among patients undergoing emergency surgical intervention for acute SCI.

Hospital complications and costs of spinal arteriovenous malformations in the United States from 2002-2014.

BACKGROUND: Spinal arteriovenous malformations (AVMs) are rare disease entities with significant morbidity if untreated. Risk factors of complications, hospitalization and costs-of-care remain in need of characterization. METHODS: Using the National Inpatient Sample years 2002-2014, adult subjects with spinal AVMs who underwent either laminectomy with lesion excision or endovascular embolization were extracted using ICD-9-CM diagnostic code 747.82. Predictors of inpatient complications, hospital length of stay (HLOS), and discharge home were evaluated using multivariable regression. Cost was evaluated using inflation-adjusted healthcare cost [charge*(cost/charge ratio)]. Mean differences (B), odds ratios (OR) and 95% CIs are reported. Significance was assessed at P<0.001. RESULTS: In 2546 weighted admissions, age was 54.4±16.5-years (laminectomy: 70.0%, embolization: 30.0%). Fifteen percent suffered inpatient complications. Cost of hospitalization was $ 41216±38511 and was elevated for subjects with complications ($67571±2636, vs. no complications: $36562±723, P<0.001). Increased costs for categories of complications ranged from $ 16525 (renal/urinary) to $62246 (thromboembolism). In surgical subjects, complications were more costly ($ 69761±2896, vs. no complications: 36520±809, P<0.001). On multivariable analysis, major/extreme disease severity and major/extreme mortality risk were associated with increased complications and HLOS (P<0.001). Elective admissions had shorter HLOS (B=-4.3-days, [-4.8, -3.8], P<0.001) and higher odds of discharge home (OR=2.6 [2.1-3.2], P<0.001). Laminectomy (vs. embolization) was associated with complications (OR=2.6, 95% CI [1.7-3.8], P<0.001), HLOS (B=3.4-days [2.9-4.0], P<0.001), and decreased discharge home (OR=0.3 [0.2-0.4], P<0.001). CONCLUSIONS: In spinal AVMs, high disease severity, non-elective admissions, and surgery are associated with complications, HLOS, and discharge to a non-home facility. Costs are elevated in patients suffering complications. Future studies are warranted.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on the Evaluation and Treatment of Patients With Thoracolumbar Spine Trauma: Neurological Assessment.

QUESTION 1: Which neurological assessment tools have demonstrated internal reliability and validity in the management of patients with thoracic and lumbar fractures (ie, do these instruments provide consistent information between different care providers)? RECOMMENDATION 1: Numerous neurologic assessment scales (Functional Independence Measure, Sunnybrook Cord Injury Scale and Frankel Scale for Spinal Cord Injury) have demonstrated internal reliability and validity in the management of patients with thoracic and lumbar fractures. Unfortunately, other contemporaneous measurement scales (ie, American Spinal Cord Injury Association Impairment Scale) have not been specifically studied in patients with thoracic and lumbar fractures. Strength of Recommendation: Grade C. QUESTION 2: Are there any clinical findings (eg, presenting neurological grade/function) in patients with thoracic and lumbar fractures that can assist in predicting clinical outcomes? RECOMMENDATION 2: Entry American Spinal Injury Association Impairment Scale grade, sacral sensation, ankle spasticity, urethral and rectal sphincter function, and AbH motor function can be used to predict neurological function and outcome in patients with thoracic and lumbar fractures (Table I https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_4_table1). Strength of Recommendation: Grade B The full version of the guideline can be reviewed at: https://www.cns.org/guideline-chapters/congress-neurological-surgeons-systematic-review-evidence-based-guidelines/chapter_4.

Bone Morphogenic Protein Use in Spinal Surgery.

Bone morphogenic protein (BMP) provides excellent enhancement of fusion in many spinal surgeries. BMP should be a cautionary tale about the use of industry-sponsored research, perceived conflicts of interest, and holding the field of spinal surgery to the highest academic scrutiny and ethical standards. In the case of BMP, not having a transparent base of literature as it was approved led to delays in allowing this superior technology to help patients.

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 2: assessment of functional outcome following lumbar fusion.

Assessment of functional patient-reported outcome following lumbar spinal fusion continues to be essential for comparing the effectiveness of different treatments for patients presenting with degenerative disease of the lumbar spine. When assessing functional outcome in patients being treated with lumbar spinal fusion, a reliable, valid, and responsive outcomes instrument such as the Oswestry Disability Index should be used. The SF-36 and the SF-12 have emerged as dominant measures of general health-related quality of life. Research has established the minimum clinically important difference for major functional outcomes measures, and this should be considered when assessing clinical outcome. The results of recent studies suggest that a patient's pretreatment psychological state is a major independent variable that affects the ability to detect change in functional outcome.

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 3: assessment of economic outcome.

A comprehensive economic analysis generally involves the calculation of indirect and direct health costs from a societal perspective as opposed to simply reporting costs from a hospital or payer perspective. Hospital charges for a surgical procedure must be converted to cost data when performing a cost-effectiveness analysis. Once cost data has been calculated, quality-adjusted life year data from a surgical treatment are calculated by using a preference-based health-related quality-of-life instrument such as the EQ-5D. A recent cost-utility analysis from a single study has demonstrated the long-term (over an 8-year time period) benefits of circumferential fusions over stand-alone posterolateral fusions. In addition, economic analysis from a single study has found that lumbar fusion for selected patients with low-back pain can be recommended from an economic perspective. Recent economic analysis, from a single study, finds that femoral ring allograft might be more cost-effective compared with a specific titanium cage when performing an anterior lumbar interbody fusion plus posterolateral fusion.

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 4: radiographic assessment of fusion status.

The ability to identify a successful arthrodesis is an essential element in the management of patients undergoing lumbar fusion procedures. The hypothetical gold standard of intraoperative exploration to identify, under direct observation, a solid arthrodesis is an impractical alternative. Therefore, radiographic assessment remains the most viable instrument to evaluate for a successful arthrodesis. Static radiographs, particularly in the presence of instrumentation, are not recommended. In the absence of spinal instrumentation, lack of motion on flexion-extension radiographs is highly suggestive of a successful fusion; however, motion observed at the treated levels does not necessarily predict pseudarthrosis. The degree of motion on dynamic views that would distinguish between a successful arthrodesis and pseudarthrosis has not been clearly defined. Computed tomography with fine-cut axial images and multiplanar views is recommended and appears to be the most sensitive for assessing fusion following instrumented posterolateral and anterior lumbar interbody fusions. For suspected symptomatic pseudarthrosis, a combination of techniques including static and dynamic radiographs as well as CT images is recommended as an option. Lack of facet fusion is considered to be more suggestive of a pseudarthrosis compared with absence of bridging posterolateral bone. Studies exploring additional noninvasive modalities of fusion assessment have demonstrated either poor potential, such as with (99m)Tc bone scans, or provide insufficient information to formulate a definitive recommendation.

Treatment of cervical stenotic myelopathy: a cost and outcome comparison of laminoplasty versus laminectomy and lateral mass fusion.

OBJECT: Cervical stenotic myelopathy due to spondylosis or ossification of the posterior longitudinal ligament is often treated with laminoplasty or cervical laminectomy (with fusion). The goal of this study was to compare outcomes, radiographic results, complications, and implant costs associated with these 2 treatments. METHODS: The authors analyzed the records of 56 patients (age range 42­81 years) who were surgically treated for cervical stenosis. Of this group, 30 underwent laminoplasty and 26 underwent laminectomy with fusion. Patients who had cervical kyphosis or spondylolisthesis were excluded. An average of 4 levels were instrumented in the laminoplasty group and 5 levels in the fusion group (p < 0.01). Forty-two percent of the fusions crossed the cervicothoracic junction, but no laminoplasty instrumentation crossed the cervicothoracic junction, and it only reached C-7 in one-third of the cases. Preoperative and postoperative Nurick grades and modified Japanese Orthopaedic Association (mJOA) scores were obtained. Outcomes were also assessed with neck pain visual analog scale (VAS) scores and the Odom outcome criteria. Postoperative length of stay, complications, and implant costs were calculated. RESULTS: The mean duration of follow-up, average patient age, and length of hospital stay were similar for both groups. The mean Nurick scores were also similar in the 2 groups and improved an average of 1.4 points in both (p < 0.01 for preoperative-postoperative comparison in each group). The mean mJOA scores improved 2.7 points in laminoplasty patients and 2.8 points in fusion patients (p < 0.01 for each group). The mean VAS scores for neck pain did not change significantly in the laminoplasty cohort (3.2 ± 2.8 [SD] preoperatively vs 3.4 ± 2.6 postoperatively, p = 0.50). In the fusion cohort, the mean VAS scores improved from 5.8 ± 3.2 to 3.0 ± 2.3 (p < 0.01). Excellent or good Odom outcomes were observed in 76.7% of the patients in the laminoplasty cohort and 80.8% of those in the fusion cohort (p = 0.71). In the fusion group, complications were twice as common and implant costs were nearly 3 times as high as in the laminoplasty group. When cases involving fusions crossing the cervicothoracic junction were excluded, analysis showed similar complication rates in the 2 groups. CONCLUSIONS: Patients treated with laminoplasty and patients treated with laminectomy and fusion had similar improvements in Nurick scores, mJOA scores, and Odom outcomes. Patients who underwent fusion typically had higher preoperative neck pain scores, but their neck pain improved significantly after surgery. There was no significant change in the neck pain scores of patients treated with laminoplasty. Our series suggests cervical fusion significantly reduces neck pain in patients with stenotic myelopathy, but that the cost of the implant and rate of reoperation are greater than in laminoplasty.

The Mini-Open transpedicular thoracic discectomy: surgical technique and assessment.

OBJECT: Thoracic disc herniations can be surgically treated with a number of different techniques and approaches. However, surgical outcomes comparing the various techniques are rarely reported in the literature. The authors describe a minimally invasive technique to approach thoracic disc herniations via a transpedicular route with the use of tubular retractors and microscope visualization. This technique provides a safe method to identify the thoracic disc space and perform a decompression with minimal paraspinal soft tissue disruption. The authors compare the results of this approach with clinical results after open transpedicular discectomy. METHODS: The authors performed a retrospective cohort study comparing results in 11 patients with symptomatic thoracic disc herniations treated with either open posterolateral (4 patients) or mini-open transpedicular discectomy (7 patients). Hospital stay, blood loss, modified Prolo score, and Frankel score were used as outcome variables. RESULTS: Patients who underwent mini-open transpedicular discectomy had less blood loss and showed greater improvement in modified Prolo scores (p = 0.024 and p = 0.05, respectively) than those who underwent open transpedicular discectomy at the time of early follow-up within 1 year of surgery. However, at an average of 18 months of follow-up, the Prolo score difference between the 2 surgical groups was not statistically significant. There were no major or minor surgical complications in the patients who received the minimally invasive technique. CONCLUSIONS: The mini-open transpedicular discectomy for thoracic disc herniations results in better modified Prolo scores at early postoperative intervals and less blood loss during surgery than open posterolateral discectomy. The authors' technique is described in detail and an intraoperative video is provided.