Friedman's Gradient-Boosting Algorithm Predicts Lactate-Pyruvate Ratio Predicts Trends in Cases of Intracerebral Hemorrhages.

OBJECTIVE: The local effects of an intracerebral hemorrhage (ICH) on surrounding brain tissue can be detected bedside using multimodal brain monitoring techniques. The aim of this study is to design a gradient boosting regression model using the R package boostmtree with the ability to predict lactate-pyruvate (L/P) ratio measurements in ICH. METHODS: We performed a retrospective analysis of 6 spontaneous ICH (sICH) and 6 traumatic ICH (tICH) patients who underwent surgical removal of the clot with microdialysis catheters placed in the perihematomal zone. Predictors of glucose, lactate, pyruvate, age, sex, diagnosis, and operation status were used to design our model. RESULTS: In a holdout analysis, the model forecasted L/P ratio trends in a representative in-sample testing set. We anticipate that boostmtree could be applied to designs of similar regression models to analyze trends in other MM features across other types of acute brain injury. CONCLUSION: The model successfully predicted hourly L/P ratios in sICH and tICH cases after the hemorrhage evacuation and displayed significantly better performance than linear models. Our results suggest that boostmtree may be a powerful tool in developing more advanced mathematical models to assess other MM parameters for cases in which the perihematomal environment is monitored.

Integration of Chronological Age Does Not Improve the Performance of a Mixed-Effect Model Using Comorbidity Burden and Frailty to Predict 90-Day Readmission After Surgery for Degenerative Scoliosis.

OBJECTIVE: We evaluated the contributions of chronological age, comorbidity burden, and/or frailty in predicting 90-day readmission in patients undergoing degenerative scoliosis surgery. METHODS: Patients were identified through the Healthcare Cost and Utilization Project Nationwide Readmissions Database. Frailty was assessed using the Johns Hopkins Adjusted Clinical Groups frailty-defining indicator. Comorbidity was assessed using the Elixhauser Comorbidity Index (ECI). Generalized linear mixed-effects models were created to predict readmission using age, frailty, and/or ECI. Area under the curve (AUC) was compared using DeLong's test. RESULTS: A total of 8104 patients were identified. Readmission rate was 9.8%, with infection representing the most common cause (3.5%). Our first model utilized chronological age, ECI, and/or frailty as primary predictors. The combination of ECI + frailty + age performed best, but the inclusion of chronological age did not significantly improve performance compared to ECI + frailty alone (AUC 0.603 vs. 0.599, P = 0.290). A second model using only chronological age and frailty as primary predictors performed better, however the inclusion of chronological age worsened performance when compared to frailty alone (AUC 0.747 vs. 0.743, P = 0.043). CONCLUSIONS: These data support frailty as a predictor of 90-day readmission within a nationally representative sample. Frailty alone performed better than combinations of ECI and age. Interestingly, the integration of chronological age did not dramatically improve the model's performance. Limitations include the use of a national registry and a single frailty index. This provides impetus to explore biological age, rather than chronological age, as a potential tool for surgical risk assessment.

A contemporary analysis of surgical ligation versus endovascular embolization in patients with intracranial dural arteriovenous fistulas: a propensity score-matched and mixed-effects model study.

OBJECTIVE: Intracranial dural arteriovenous fistulas (dAVFs) are rare vascular lesions that can be asymptomatic or can lead to devastating hemorrhage based on the dAVF's aggressiveness. Several approaches can be taken to treat dAVFs, such as endovascular embolization and surgical ligation. However, very few studies have evaluated the influence of surgery compared to endovascular approaches on patient outcomes. This study was performed to analyze the clinical characteristics and outcomes of patients who underwent treatment for intracranial dAVF in which either endovascular embolization or microsurgical ligation was used. METHODS: The Nationwide Readmissions Database was reviewed for all patients who underwent treatment for dAVFs (n = 18,152) between 2016 and 2019. Patients who received only surgical ligation or endovascular embolization (i.e., not both) were included. Variables regarding demographics, clinical outcomes, and healthcare utilization were queried. Primary outcome measures were nonroutine discharge, 1-year readmission, top quartile length of stay (LOS), and top quartile of inpatient all-payer cost. Propensity score matching was performed to evaluate the influence of either surgery or embolization on patient outcomes. Receiver operating characteristic (ROC) curves were created for each outcome measure. The area under the curve (AUC) of each ROC was used to estimate mixed-effects model performance. RESULTS: Following propensity score matching, 127 and 113 patients made up the surgical ligation and endovascular embolization cohort, respectively. There were no differences found in age (p = 0.16), sex (p = 0.57), or average Elixhauser Comorbidity Index (p = 0.32). Patients receiving surgical ligation had lower odds of readmission (OR 0.37, p = 0.028) and greater odds of nonroutine discharge (OR 2.21, p = 0.03) compared to patients who underwent endovascular embolization. The authors found no differences in the top quartile of LOS (p = 0.84), top quartile of cost (p = 0.38), or mortality (p > 0.99) between cohorts. ROC curves revealed that the mixed-effects models inclusive of approach outperformed models agnostic to approach with respect to nonroutine discharge (AUC with approach, 0.871; AUC without approach, 0.850; p = 0.018) and readmission (AUC with approach, 0.686; AUC without approach, 0.651; p = 0.019), but no differences were observed regarding top quartile of LOS (p = 0.17) and top quartile of cost (p = 0.40). CONCLUSIONS: Surgical approach may influence perioperative outcomes in patients treated for intracranial dAVF-most significantly discharge disposition and 1-year readmission. Future longitudinal prospective studies with more clinical detail will be required to fully capture the predictive utility of surgical approach in patients treated for intracranial dAVF, particularly for various dAVF subtypes.

Risk Factors for Peripheral Nerve Injury Following Revision Total Hip Arthroplasty in 112,310 Patients.

Background: Peripheral nerve injury (PNI) following revision total hip arthroplasty (rTHA) can be a devastating complication. This study assessed the frequency of and risk factors for postoperative PNI following rTHA. Methods: Patients who underwent rTHA from 2003 to 2015 were identified using the National Inpatient Sample (NIS). Demographics, medical history, surgical details, and complications were compared between patients who sustained a PNI and those who did not, to identify risk factors for the development of PNI after rTHA. Results: Overall, 112,310 patients who underwent rTHA were identified, 929 (0.83%) of whom sustained a PNI. Univariate analysis found that younger patients (p < 0.0001), females (p = 0.025), and those with a history of flexion contracture (0.65% vs. 0.22%, p = 0.005), hip dislocation (24.0% vs. 18.0%, p < 0.001), and spine conditions (4.8% vs. 2.7%, p < 0.001) had significantly higher rates of PNI. In-hospital complications associated with PNI included postoperative hematoma (2.6% vs. 1.2%, p < 0.0001), postoperative seroma (0.75% vs. 0.30%, p = 0.011), superficial wound dehiscence (0.65% vs. 0.23%, p = 0.008), and postoperative anemia (36.1% vs. 32.0%, p = 0.007). Multivariate analysis demonstrated that a history of pre-existing spine conditions (aOR: 1.7; 95%-CI: 1.3-2.4, p < 0.001), prior dislocation (aOR 1.5; 95%-CI: 1.3-1.7, p < 0.001), postoperative anemia (aOR 1.2; 95%-CI: 1.0-1.4, p = 0.01), and hematoma (aOR 2.1; 95%-CI: 1.4-3.2, p < 0.001) were associated with increased risk for PNI. Conclusions: Our findings align with the existing literature, affirming that sciatic nerve injury is the prevailing neuropathic complication after total hip arthroplasty (THA). Furthermore, we observed a 0.83% incidence of PNI following rTHA and identified pre-existing spine conditions, prior hip dislocation, postoperative anemia, or hematoma as risk factors. Orthopedic surgeons may use this information to guide their discussion of PNI following rTHA, especially in high-risk patients.

High-Value Epilepsy Care in the United States: Predictors of Increased Costs and Complications from the National Inpatient Sample Database 2016-2019.

BACKGROUND: For patients with medically refractory epilepsy, newer minimally invasive techniques such as laser interstitial thermal therapy (LITT) have been developed in recent years. This study aims to characterize trends in the utilization of surgical resection versus LITT to treat medically refractory epilepsy, characterize complications, and understand the cost of this innovative technique to the public. METHODS: The National Inpatient Sample database was queried from 2016 to 2019 for all patients admitted with a diagnosis of medically refractory epilepsy. Patient demographics, hospital length of stay, complications, and costs were tabulated for all patients who underwent LITT or surgical resection within these cohorts. RESULTS: A total of 6019 patients were included, 223 underwent LITT procedures, while 5796 underwent resection. Significant predictors of increased patient charges for both cohorts included diabetes (odds ratio: 1.7, confidence interval [CI]: 1.44-2.19), infection (odds ratio: 5.12, CI 2.73-9.58), and hemorrhage (odds ratio: 2.95, CI 2.04-4.12). Procedures performed at nonteaching hospitals had 1.54 greater odds (CI 1.02-2.33) of resulting in a complication compared to teaching hospitals. Insurance status did significantly differ (P = 0.001) between those receiving LITT (23.3% Medicare; 25.6% Medicaid; 44.4% private insurance; 6.7 Other) and those undergoing resection (35.3% Medicare; 22.5% Medicaid; 34.7% private Insurance; 7.5% other). When adjusting for patient demographics, LITT patients had shorter length of stay (2.3 vs. 8.9 days, P < 0.001), lower complication rate (1.9% vs. 3.1%, P = 0.385), and lower mean hospital ($139,412.79 vs. $233,120.99, P < 0.001) and patient ($55,394.34 vs. $37,756.66, P < 0.001) costs. CONCLUSIONS: The present study highlights LITT's advantages through its association with lower costs and shorter length of stay. The present study also highlights the associated predictors of LITT versus resection, such as that most LITT cases happen at academic centers for patients with private insurance. As the adoption of LITT continues, more data will become available to further understand these issues.

Cervical Disc Arthroplasty: Rationale, Designs, and Results of Randomized Controlled Trials.

BACKGROUND: This review outlines clinical data and characteristics of current Food and Drug Administration (FDA)-approved implants in cervical disc replacement/cervical disc arthroplasty (CDR/CDA) to provide a centralized resource for spine surgeons. METHODS: Randomized controlled trials (RCTs) on CDR/CDA were identified using a search of the PubMed, Web of Science, and Google Scholar databases. The initial search identified 69 studies. Duplicates were removed, and the following inclusion criteria were applied when determining eligibility of RCTs for the current review: (1) discussing CDR/CDA prosthesis and (2) published within between 2010 and 2020. Studies without clinical data or that were not RCTs were excluded. All articles were reviewed independently by 2 authors, with the involvement of an arbitrator to facilitate consensus on any discrepancies. RESULTS: A total of 34 studies were included in the final review. Findings were synthesized into a comprehensive table describing key features and clinical results for each FDA-approved CDR/CDA implant and are overall suggestive of expanding indications and increasing utilization. CONCLUSIONS: RCTs have provided substantial evidence to support CDR/CDA for treating single- and 2-level cervical degenerative disc disease in place of conventional anterior cervical discectomy and fusion. CLINICAL RELEVANCE: This review provides a resource that consolidates relevant clinical data for current FDA-approved implants to help spine surgeons make an informed decision during preoperative planning.

Post-Operative Complications Associated with Long-Term NSAID or Long-Term Opioid Use Prior to Lumbar Spinal Fusion Surgery.

OBJECTIVE: Lower back pain (LBP) has been implicated as a significant cause of chronic pain in the United States, often requiring analgesic use. In this study, we investigate the trends in long-term preoperative NSAID (LTN) and Opioid (LTO) use in patients with low back pain in the United States, and the resultant postoperative complications following lumbar fusion. METHODS: In this retrospective cohort study of patients with lumbar pathologies, multivariate population-based regression models were developed using the 2010-2017 National Readmission Database. Short-term complications (30-, 90-day) and long-term complications (180-, 300-day) were analyzed at readmission. RESULTS: Of patients diagnosed with LBP (N = 1427,190) we found a rise in LTO users and a fall in LTN users following 2015. We identified 654,264 individuals who received a lumbar spine fusion, of which 22,975 were LTN users and 11,213 were LTO users. LTO users had significantly higher total inpatient charges (p-value<0.0001) and LOS (p-value<0.0001), while LTN users had lower rates of acute infection (OR: 0.993, 95% CI: 0.987-0.999, p = 0.017) and acute posthemorrhagic anemia (OR: 0.957, 95% CI: 0.935-0.979, p < 0.001) at primary admission. Readmission analysis showed that LTN use had significantly lower odds of readmission compared to LTO use at all time points (p < 0.01 for all). LTN use had significantly higher odds of hardware failure (OR: 1.134, 95% CI: 1.039-1.237, p = 0.005) within 300-days of receiving a lumbar fusion. CONCLUSIONS: LTO users had significantly higher readmission rates compared to LTN. In addition, we found that LTN use was associated with significantly higher odds of hardware failure at long-term follow-up in patients receiving lumbar fusion surgery.

Developing Mixed-Effects Models to Compare the Predictive Ability of Various Comorbidity Indices in a Contemporary Cohort of Patients Undergoing Lumbar Fusion.

BACKGROUND AND OBJECTIVE: As incidence of operative spinal pathology continues to grow, so do the rates of lumbar spinal fusion procedures. Comorbidity indices can be used preoperatively to predict potential complications. However, there is a paucity of research defining the optimal comorbidity indices in patients undergoing spinal fusion surgery. We aimed to use modeling strategies to evaluate the predictive validity of various comorbidity indices and combinations thereof. METHODS: Patients who underwent spinal fusion were queried using data from the Nationwide Readmissions Database for the years 2016 through 2019. Using comorbidity indices as predictor variables, receiver operating characteristic curves were developed for pertinent complications such as mortality, nonroutine discharge, top-quartile cost, top-quartile length of stay, and 30-day readmission. RESULTS: A total of 750 183 patients were included. Nonroutine discharges occurred in 161 077 (21.5%) patients. The adjusted all-payer cost for the procedure was $37 616.97 ± $27 408.86 (top quartile: $45 409.20), and the length of stay was 4.1 ± 4.4 days (top quartile: 8.1 days). By comparing receiver operating characteristics of various models, it was found that models using Frailty + Elixhauser Comorbidity Index (ECI) as the primary predictor performed better than other models with statistically significant P -values on post hoc testing. However, for prediction of mortality, the model using Frailty + ECI was not better than the model using ECI alone ( P = .23), and for prediction of all-payer cost, the ECI model outperformed the models using frailty alone ( P < .0001) and the model using Frailty + ECI ( P < .0001). CONCLUSION: This investigation is the first to use big data and modeling strategies to delineate the relative predictive utility of the ECI and Johns Hopkins Adjusted Clinical Groups comorbidity indices for the prognostication of patients undergoing lumbar fusion surgery. With the knowledge gained from our models, spine surgeons, payers, and hospitals may be able to identify vulnerable patients more effectively within their practice who may require a higher degree of resource utilization.

Risk Factors for Peripheral Nerve Injury Following Revision Total Knee Arthroplasty in 132,960 Patients.

BACKGROUND: Peripheral nerve injury (PNI) following revision total knee arthroplasty (rTKA) is a potentially devastating injury for patients. This study assessed the frequency of and risk factors for postoperative PNI following rTKA. METHODS: Patients who underwent rTKA from 2003 to 2015 were identified using the National Inpatient Sample. Demographics, medical histories, surgical details, and complications were compared between patients who sustained a PNI and those who did not to identify risk factors for the development of PNI after rTKA. RESULTS: Overall, 132,960 patients who underwent rTKA were identified, and 737 (0.56%) sustained a postoperative PNI. After adjusting for confounders, patients with a history of a spine condition (adjusted odds ratio [aOR]: 1.7, 95%-confidence interval 1.2 to 2.4, P = .003) and postoperative anemia (aOR: 1.3, 95%-CI: 1.1 to 1.5, P = .004) had higher risk of PNI following rTKA. Intraoperative periprosthetic fracture (aOR: 1.3, 0.78 to 2.2, P = .308), rheumatoid arthritis (aOR: 1.0, 95%-CI: 0.68 to 1.6, P = .865), and history of knee dislocation (aOR: 1.1, 95%-CI: 0.85 to 1.5, P = .412), were not significantly associated with higher risk for PNI. CONCLUSIONS: This study found a 0.56% incidence of PNI following rTKA, and patients who had preexisting spine conditions or postoperative anemia were at an increased risk for this complication. Orthopedic surgeons may use the results of this study to appropriately counsel patients on the potential for a PNI following rTKA.

The Influence of Hospital Type, Insurance Type, and Patient Income on 30-Day Complication and Readmission Rates Following Lumbar Spine Fusion.

BACKGROUND CONTEXT: Several studies have shown that factors such as insurance type and patient income are associated with different readmission rates following certain orthopaedic procedures. The literature, however, remains sparse with regard to these demographic characteristics and their associations to perioperative lumbar spine fusion outcomes. PURPOSE: The purpose of this study was to assess the associations between hospital type, insurance type, and patient median income to both 30-day complication and readmission rates following lumbar spine fusion. PATIENT SAMPLE: Patients who underwent primary lumbar spine fusion (n = 596,568) from 2010-2016 were queried from the National Readmissions Database (NRD). OUTCOME MEASURES: Incidence of 30-day complication and readmission rates. METHODS: All relevant diagnoses and procedures were identified using International Classification of Disease, 9th and 10th Edition (ICD-9, 10) codes. Hospital types were categorized as metropolitan non-teaching (n = 212,131), metropolitan teaching (n = 364,752), and rural (n = 19,685). Insurance types included: Medicare (n = 213,534), Medicaid (n = 78,520), private insurance (n = 196,648), and out-of-pocket (n = 45,025). Patient income was divided into the following quartiles: Q1 (n = 112,083), Q2 (n = 145,755), Q3 (n = 156,276), and Q4 (n = 147,289), wherein quartile 1 corresponded to lower income ranges and quartile 4 to higher ranges. Statistical analysis was conducted in R. Kruskal-Wallis tests with Dunn's pairwise comparisons were performed to analyze differences in 30-day readmission and complication rates in patients who underwent lumbar spine fusion. Complications analyzed included infection, wound injury, hematoma, neurological injury, thromboembolic event, and hardware failure. RESULTS: 30-day readmission was significantly higher in metropolitan teaching hospitals compared to metropolitan non-teaching hospitals and rural hospitals (P < .05). Patients from metropolitan teaching hospitals had significantly higher rates of infection (P < .001), wound injury (P < .001), hematoma (P = .018), and hardware failure (P < .002) compared to those treated at metropolitan non-teaching hospitals. Privately insured patients were significantly less likely to be readmitted at 30 days than those paying with Medicare or Medicaid (P < .01). Patients with private insurance also experienced significantly lower rates of hematoma formation than Medicare beneficiaries and out-of-pocket payers (P < .01), postoperative wound injury compared to Medicaid patients and out-of-pocket payers (P < .005), and infection compared to all other groups (P < .001). Patients in Quartile 4 experienced significantly greater rates of hematoma formation compared to those in Quartiles 1 and 2 and were more likely to experience a thromboembolic event compared to all other groups. CONCLUSION: Patients undergoing lumbar spine fusion at metropolitan non-teaching hospitals and paying with private insurance had significantly lower 30-day readmission rates than their counterparts. Complications within 30 days following lumbar spine fusion were significantly higher in patients treated at metropolitan teaching hospitals and in Medicare and Medicaid beneficiaries. Aside from a few exceptions, however, patient income was generally not associated with differential complication rates.

Stroke management and outcomes in low-income and lower-middle-income countries: a meta-analysis of 8535 patients.

OBJECTIVE: Strokes affect almost 13 million new people each year, and whereas the outcomes of stroke have improved over the past several decades in high-income countries, the same cannot be seen in low-income and lower-middle-income countries. This is the first study to identify the availability of diagnostic tools along with the rates of stroke mortality and other poststroke complications in low-income and lower-middle-income countries. METHODS: A review of the literature was completed with a search of the MEDLINE, Embase, and Scopus databases, with adherence to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they reported any outcomes of stroke in low-income and lower-middle-income countries as designated by the World Bank classification. A meta-analysis calculating pooled prevalence rates of diagnostic characteristics and stroke outcomes was completed for all endpoint variables. RESULTS: A total of 19 studies were included, of which 6 came from Ethiopia, 3 from Zambia, and 2 each from Tanzania and Iran. Single studies from Zimbabwe, Botswana, Senegal, Cameroon, Uganda, and Sierra Leone were included. A total of 5265 (61.7%) patients had an ischemic stroke, 2124 (24.9%) had hemorrhagic stroke, with the remaining 1146 (13.4%) having an unknown type. Among 6 studies the pooled percentage of patients presenting to hospital within 1 day was 48.37% (95% CI 38.59%-58.27%; I2 = 97.0%, p < 0.01). The pooled in-hospital mortality rate was 19.81% (95% CI 15.26%-25.31%; I2 = 91%, p < 0.01), but was higher in a hemorrhagic subgroup (27.07% [95% CI 22.52%-32.15%; I2 = 54%, p = 0.05]) when compared to an ischemic group (13.16% [95% CI 8.60%-19.62%; I2 = 87%, p < 0.01]). The 30-day pooled mortality rate was 23.24% (95% CI 14.17%-35.70%; I2 = 93%, p < 0.01). At 30 days, the functional independence (modified Rankin Scale score 0-2) pooled rate was 13.10% (95% CI 7.50%-21.89%; I2 = 82%, p < 0.01). CONCLUSIONS: A severe healthcare disparity is present in low-income and lower-middle-income countries, where there is delayed diagnosis of strokes and increased rates of poor clinical outcomes for these patients.

Association between frailty status and complications in patients undergoing surgical excision of malignant esophageal neoplasms.

Background: Research within the last decade highlights the patients' frailty status as an important predictor of esophageal cancer outcomes, but the literature evaluating frailty's role in these patients remains limited. We evaluated the role of frailty in patients undergoing resection of malignant esophageal neoplasms. Methods: We used the Nationwide Readmissions Database from 2016 and 2017 to identify patients who underwent excision of a malignant esophageal neoplasm. Patient frailty was queried using the Johns Hopkins Adjusted Clinical Groups frailty-defining diagnosis indicator. Propensity score matching identified 289 frail patients and 281 non-frail patients. Mann-Whitney U testing was performed and receiver operating characteristic (ROC) curves were created, following the creation of logistic regression models for predicting discharge disposition. The area under the curve (AUC) served as a proxy for model performance. Results: Frail patients had significantly more nonroutine discharges, longer inpatient lengths of stay, higher costs, more acute infections, posthemorrhagic anemia and deep vein thrombosis, and greater mortality (P<0.05). No significant differences were found between the 2 cohorts with respect to readmission rates, pulmonary embolism or dysphagia. Predictive models for patient discharge disposition demonstrated that frailty status in combination with age resulted in better ROC curves (AUC: 0.652) compared to models using age alone (AUC: 0.601). Conclusions: Frailty was found to be significantly correlated with higher rates of inpatient medical complications following esophagectomy. The inclusion of patient frailty status in predictive models for discharge disposition resulted in a better predictive capacity compared to those using age alone.

The Influence of Modifiable Risk Factors on Postoperative Outcomes in Patients Receiving Surgery for Resection for Acoustic Neuroma.

Acoustic neuromas are the most common tumor of the cerebellopontine angle that are associated with a number of symptoms that negatively impact a patient's quality of life. While the mainstay of treatment for these benign tumors remains microsurgical resection, there is limited research exploring how certain modifiable risk factors (MRFs) may affect the perioperative course. The purpose of this study was to investigate how MRFs including malnutrition, obesity, dyslipidemia, uncontrolled hypertension, and smoking may affect postoperative rates of readmission and nonroutine discharges. We utilized the 2016 and 2017 Healthcare Cost and Utilization Project Nationwide Readmissions Database. MRFs were queried using appropriate International Classification of Diseases, Tenth Revision (ICD-10) coding for categories including malnutrition, obesity, dyslipidemia, smoking, alcohol, and hypertension. The statistical analysis was done using RStudio (Version 1.3.959). Chi-squared tests were done to evaluate differences between categorical variables. The Mann-Whitney U-testing was utilized to evaluate for statistically significant differences in continuous data. The "Epitools" package was used to develop logistic regression models for postoperative complications and post hoc receiver operating characteristic curves were developed. Pertaining to nonroutine discharge, predictive models using malnutrition outperformed all other MRFs as well as those with no MRFs (P < .05). In the case of readmission, models using malnutrition outperformed those of obesity and smoking (P < .05). Again, an increase in predictive power is seen in models using dyslipidemia when compared to obesity, smoking, or uncontrolled hypertension. Lastly, models using no MRFs outperformed those of obesity, smoking, and uncontrolled hypertension (P < .05). This is the first study of its kind to evaluate the role of MRFs in those undergoing surgical resection of their acoustic neuroma. We concluded that certain MRFs may play a role in complicating a patient's perioperative surgical course.

Developing Mixed-effects Models to Optimize Prediction of Postoperative Outcomes in a Modern Sample of Over 450,000 Patients Undergoing Elective Cervical Spine Fusion Surgery.

STUDY DESIGN: A retrospective cohort. OBJECTIVE: We utilize big data and modeling techniques to create optimized comorbidity indices for predicting postoperative outcomes following cervical spine fusion surgery. SUMMARY OF BACKGROUND DATA: Cervical spine decompression and fusion surgery are commonly used to treat degenerative cervical spine pathologies. However, there is a paucity of high-quality data defining the optimal comorbidity indices specifically in patients undergoing cervical spine fusion surgery. METHODS: Using data from 2016 to 2019, we queried the Nationwide Readmissions Database (NRD) to identify individuals who had received cervical spine fusion surgery. The Johns Hopkins Adjusted Clinical Groups (JHACG) frailty-defining indicator was used to assess frailty. To measure the level of comorbidity, Elixhauser Comorbidity Index (ECI) scores were queried. Receiver operating characteristic curves were developed utilizing comorbidity indices as predictor variables for pertinent complications such as mortality, nonroutine discharge, top-quartile cost, top-quartile length of stay, and 1-year readmission. RESULTS: A total of 453,717 patients were eligible. Nonroutine discharges occurred in 93,961 (20.7%) patients. The mean adjusted all-payer cost for the procedure was $22,573.14±18,274.86 (top quartile: $26,775.80) and the mean length of stay was 2.7±4.4 days (top quartile: 4.7 d). There were 703 (0.15%) mortalities and 58,254 (12.8%) readmissions within 1 year postoperatively. Models using frailty+ECI as primary predictors consistently outperformed the ECI-only model with statistically significant P -values for most of the complications assessed. Cost and mortality were the only outcomes for which this was not the case, as frailty outperformed both ECI and frailty+ECI in cost ( P <0.0001 for all) and frailty+ECI performed as well as ECI alone in mortality ( P =0.10). CONCLUSIONS: Our data suggest that frailty+ECI may most accurately predict clinical outcomes in patients receiving cervical spine fusion surgery. These models may be used to identify high-risk populations and patients who may necessitate greater resource utilization following elective cervical spinal fusion.

Developing Predictive Models to Anticipate Shunt Complications in 33,248 Pediatric Patients with Shunted Hydrocephalus Utilizing Machine Learning.

INTRODUCTION: Hydrocephalus is a common pediatric neurosurgical pathology, typically treated with a ventricular shunt, yet approximately 30% of patients experience shunt failure within the first year after surgery. As a result, the objective of the present study was to validate a predictive model of pediatric shunt complications with data retrieved from the Healthcare Cost and Utilization Project (HCUP) National Readmissions Database (NRD). METHODS: The HCUP NRD was queried from 2016 to 2017 for pediatric patients undergoing shunt placement using ICD-10 codes. Comorbidities present upon initial admission resulting in shunt placement, Johns Hopkins Adjusted Clinical Groups (JHACG) frailty-defining criteria, and Major Diagnostic Category (MDC) at admission classifications were obtained. The database was divided into training (n = 19,948), validation (n = 6,650), and testing (n = 6,650) datasets. Multivariable analysis was performed to identify significant predictors of shunt complications which were used to develop logistic regression models. Post hoc receiver operating characteristic (ROC) curves were created. RESULTS: A total of 33,248 pediatric patients aged 6.9 ± 5.7 years were included. Number of diagnoses during primary admission (OR: 1.05, 95% CI: 1.04-1.07) and initial neurological admission diagnoses (OR: 3.83, 95% CI: 3.33-4.42) positively correlated with shunt complications. Female sex (OR: 0.87, 95% CI: 0.76-0.99) and elective admissions (OR: 0.62, 95% CI: 0.53-0.72) negatively correlated with shunt complications. ROC curve for the regression model utilizing all significant predictors of readmission demonstrated area under the curve of 0.733, suggesting these factors are possible predictors of shunt complications in pediatric hydrocephalus. CONCLUSION: Efficacious and safe treatment of pediatric hydrocephalus is of paramount importance. Our machine learning algorithm delineated possible variables predictive of shunt complications with good predictive value.

The Pterional Keyhole Craniotomy Approach: A Historical Perspective.

The pterional craniotomy is a workhorse of cranial surgery that provides access to the anterior and middle fossae. However, newer "keyhole" approaches, such as the micropterional or pterional keyhole craniotomy (PKC) can offer similar exposure for many pathologies while reducing surgical morbidity. The PKC is associated with shorter hospitalizations, reduced operative time, and superior cosmetic outcomes. Furthermore, it represents an ongoing trend toward smaller craniotomy size for elective cranial procedures. In this historical vignette, we trace the history of the PKC from its origins to its current role in the neurosurgeon's armamentarium.

Retrospective single-surgeon study of prone versus lateral robotic pedicle screw placement: a CT-based assessment of accuracy.

OBJECTIVE: Lateral lumbar interbody fusion including anterior-to-psoas oblique lumbar interbody fusion has conventionally relied on pedicle screw placement (PSP) for construct stabilization. Single-position surgery with lumbar interbody fusion in the lateral decubitus position with concomitant PSP has been associated with increased operative efficiency. What remains unclear is the accuracy of PSP with robotic guidance when compared with the more familiar prone patient positioning. The present study aimed to compare robot-assisted screw placement accuracy between patients with instrumentation placed in the prone and lateral positions. METHODS: The authors identified all consecutive patients treated with interbody fusion and PSP in the prone or lateral position by a single surgeon between January 2019 and October 2022. All pedicle screws placed were analyzed using CT scans to determine appropriate positioning according to the Gertzbein-Robbins classification grading system (grade C or worse was considered as a radiographically significant breach). Multivariate logistic regression models were constructed to identify risk factors for the occurrence of a radiographically significant breach. RESULTS: Eighty-nine consecutive patients (690 screws) were included, of whom 46 (477 screws) were treated in the prone position and 43 (213 screws) in the lateral decubitus position. There were fewer breaches in the prone (n = 13, 2.7%) than the lateral decubitus (n = 15, 7.0%) group (p = 0.012). Nine (1.9%) radiographically significant breaches occurred in the prone group compared with 10 (4.7%) in the lateral decubitus group (p = 0.019), for a prone versus lateral decubitus PSP accuracy rate of 98.1% versus 95.3%. There were no significant differences in BMI between prone versus lateral decubitus cohorts (30.1 vs 29.6) or patients with screw breach versus those without (31.2 vs 29.5). In multivariate models, the prone position was the only significant protective factor for screw accuracy; no other significant risk factors for screw breach were identified. CONCLUSIONS: The present data suggest that pedicle screws placed with robotic assistance have higher placement accuracy in the prone position. Further studies will be needed to validate the accuracy of PSP in the lateral position as single-position surgery becomes more commonplace in the treatment of spinal disorders.

Developing nonlinear k-nearest neighbors classification algorithms to identify patients at high risk of increased length of hospital stay following spine surgery.

OBJECTIVE: Spondylolisthesis is a common operative disease in the United States, but robust predictive models for patient outcomes remain limited. The development of models that accurately predict postoperative outcomes would be useful to help identify patients at risk of complicated postoperative courses and determine appropriate healthcare and resource utilization for patients. As such, the purpose of this study was to develop k-nearest neighbors (KNN) classification algorithms to identify patients at increased risk for extended hospital length of stay (LOS) following neurosurgical intervention for spondylolisthesis. METHODS: The Quality Outcomes Database (QOD) spondylolisthesis data set was queried for patients receiving either decompression alone or decompression plus fusion for degenerative spondylolisthesis. Preoperative and perioperative variables were queried, and Mann-Whitney U-tests were performed to identify which variables would be included in the machine learning models. Two KNN models were implemented (k = 25) with a standard training set of 60%, validation set of 20%, and testing set of 20%, one with arthrodesis status (model 1) and the other without (model 2). Feature scaling was implemented during the preprocessing stage to standardize the independent features. RESULTS: Of 608 enrolled patients, 544 met prespecified inclusion criteria. The mean age of all patients was 61.9 ± 12.1 years (± SD), and 309 (56.8%) patients were female. The model 1 KNN had an overall accuracy of 98.1%, sensitivity of 100%, specificity of 84.6%, positive predictive value (PPV) of 97.9%, and negative predictive value (NPV) of 100%. Additionally, a receiver operating characteristic (ROC) curve was plotted for model 1, showing an overall area under the curve (AUC) of 0.998. Model 2 had an overall accuracy of 99.1%, sensitivity of 100%, specificity of 92.3%, PPV of 99.0%, and NPV of 100%, with the same ROC AUC of 0.998. CONCLUSIONS: Overall, these findings demonstrate that nonlinear KNN machine learning models have incredibly high predictive value for LOS. Important predictor variables include diabetes, osteoporosis, socioeconomic quartile, duration of surgery, estimated blood loss during surgery, patient educational status, American Society of Anesthesiologists grade, BMI, insurance status, smoking status, sex, and age. These models may be considered for external validation by spine surgeons to aid in patient selection and management, resource utilization, and preoperative surgical planning.

Cemented versus Cementless Femoral Fixation for Elective Primary Total Hip Arthroplasty: A Nationwide Analysis of Short-Term Complication and Readmission Rates.

Cementless fixation during total hip arthroplasty (THA) is the predominant mode of fixation utilized for both acetabular and femoral components during elective primary THAs performed in the United States. This study aims to compare early complication and readmission rates between primary THA patients receiving cemented versus cementless femoral fixation. The 2016-2017 National Readmissions Database was queried to identify patients undergoing elective primary THA. Postoperative complication and readmission rates at 30, 90, and 180 days were compared between cemented and cementless cohorts. Univariate analysis was conducted to compare differences between cohorts. Multivariate analysis was performed to account for confounding variables. Of 447,902 patients, 35,226 (7.9%) received cemented femoral fixation, while 412,676 (92.1%) did not. The cemented group was older (70.0 vs. 64.8, p < 0.001), more female (65.0% vs. 54.3%, p < 0.001), and more comorbid (CCI 3.65 vs. 3.22, p < 0.001) compared to the cementless group. On univariate analysis, the cemented cohort had decreased odds of periprosthetic fracture at 30 days postoperatively (OR: 0.556, 95%-CI 0.424-0.729, p < 0.0001), but higher odds of hip dislocation, periprosthetic joint infection, aseptic loosening, wound dehiscence, readmission, medical complications, and death at all timepoints. On multivariate analysis, the cemented fixation cohort demonstrated reduced odds of periprosthetic fracture at all postoperative timepoints: 30 (OR: 0.350, 95%-CI 0.233-0.506, p < 0.0001), 90 (OR: 0.544, 95%-CI 0.400-0.725, p < 0.0001), and 180 days (OR: 0.573, 95%-CI 0.396-0.803, p = 0.002). Cemented femoral fixation was associated with significantly fewer short-term periprosthetic fractures, but more unplanned readmissions, deaths, and postoperative complications compared to cementless femoral fixation in patients undergoing elective THA.