On the development and validation of large language model-based classifiers for identifying social determinants of health.

The assessment of social determinants of health (SDoH) within healthcare systems is crucial for comprehensive patient care and addressing health disparities. Current challenges arise from the limited inclusion of structured SDoH information within electronic health record (EHR) systems, often due to the lack of standardized diagnosis codes. This study delves into the transformative potential of large language models (LLM) to overcome these challenges. LLM-based classifiers-using Bidirectional Encoder Representations from Transformers (BERT) and A Robustly Optimized BERT Pretraining Approach (RoBERTa)-were developed for SDoH concepts, including homelessness, food insecurity, and domestic violence, using synthetic training datasets generated by generative pre-trained transformers combined with authentic clinical notes. Models were then validated on separate datasets: Medical Information Mart for Intensive Care-III and our institutional EHR data. When training the model with a combination of synthetic and authentic notes, validation on our institutional dataset yielded an area under the receiver operating characteristics curve of 0.78 for detecting homelessness, 0.72 for detecting food insecurity, and 0.83 for detecting domestic violence. This study underscores the potential of LLMs in extracting SDoH information from clinical text. Automated detection of SDoH may be instrumental for healthcare providers in identifying at-risk patients, guiding targeted interventions, and contributing to population health initiatives aimed at mitigating disparities.

Paravertebral versus Pectoralis-II (Interpectoral and Pectoserratus) Nerve Blocks for Postoperative Analgesia after Non-Mastectomy Breast Surgery: A Randomized, Controlled, Observer-Masked Noninferiority Trial.

BACKGROUND: Pectoralis-II and paravertebral nerve blocks are both used to treat pain following breast surgery. Most previous studies involving mastectomy identified little difference of significance between the two approaches. Whether this is also accurate for non-mastectomy procedures remains unknown. METHODS: Participants undergoing uni- or bilateral non-mastectomy breast surgery anticipated to have at least moderate postoperative pain were randomized to a pectoralis-II or paravertebral block (90 mg ropivacaine/side for both). Surgeons and recovery room staff were masked to treatment group assignment, and participants were not informed of their treatment group. Injectate for pectoralis-II blocks was ropivacaine 0.3% (30 mL) per side. Injectate for paravertebral blocks was ropivacaine 0.5% (9 mL in each of 2 levels) per side. We hypothesized that pectoralis-II blocks would have noninferior (1) analgesia [Numeric Rating Scale] and (2) cumulative opioid consumption within the operating and recovery rooms combined (dual primary outcomes). The study was adequately powered with n=100, but the target enrollment was raised to n=150 to account for higher-than-anticipated variability. RESULTS: The trial was ended prematurely with 119 (79%) of the original target of 150 participants enrolled due to (masked) surgeon preference. Within the recovery room, pain scores were higher in participants with pectoralis-II (n=60) than paravertebral blocks (n=59): median [IQR] 3.3 [2.3, 4.8] vs 1.3 [0, 3.6]; 95% CI: 0.5 to 2.6; P < 0.001. Similarly, intravenous morphine equivalents were higher in the pectoralis-II group: 17.5 [12.5, 21.9] vs 10.0 mg [10, 20]; 95% CI: 0.1 to 7.5; P = 0.004. No block-related adverse events were identified in either group. CONCLUSIONS: Following non-mastectomy breast surgery, 2-level paravertebral blocks provided superior analgesia and opioid sparing compared with pectoralis-II blocks. This is a contrary finding to the majority of studies in patients having mastectomy in which little significant difference was identified between the two types of blocks.

Robot-assisted laparoscopic nephrectomy: early outcome measures with the implementation of multimodal analgesia and intrathecal morphine via the acute pain service.

PURPOSE: The objective of this study was to perform a retrospective cohort analysis, in which we measured the association of an acute pain service (APS)-driven multimodal analgesia protocol that included preoperative intrathecal morphine (ITM) compared to historic controls (i.e., surgeon-driven analgesia protocol without ITM) with postoperative opioid use. METHODS: This was a retrospective cohort study in which the primary objective was to determine whether there was a decrease in median 24-h opioid consumption (intravenous morphine equivalents [MEQ]) among robotic nephrectomy patients whose pain was managed by the surgical team prior to the APS, versus pain managed by APS. Secondary outcomes included opioid consumption during the 24-48 h and 48-72 h period and hospital length of stay. To create matched cohorts, we performed 1:1 (APS:non-APS) propensity score matching. Due to the cohorts occurring at the different time periods, we performed a segmented regression analysis of an interrupted time series. RESULTS: There were 76 patients in the propensity-matched cohorts, in which 38 (50.0%) were in the APS cohort. The median difference in 24-h opioid consumption in the pre-APS versus APS cohort was 23.0 mg [95% CI 15.0, 31.0] (p < 0.0001), in favor of APS. There were no differences in the secondary outcomes. On segmented regression, there was a statistically significant drop in 24-h opioid consumption in the APS cohort versus pre-APS cohort (p = 0.005). CONCLUSIONS: The implementation of an APS-driven multimodal analgesia protocol with ITM demonstrated a beneficial association with postoperative 24-h opioid consumption following robot-assisted nephrectomy.

Classifying High-Risk Patients for Persistent Opioid Use After Major Spine Surgery: A Machine-Learning Approach.

BACKGROUND: Persistent opioid use is a common occurrence after surgery and prolonged exposure to opioids may result in escalation and dependence. The objective of this study was to develop machine-learning-based predictive models for persistent opioid use after major spine surgery. METHODS: Five classification models were evaluated to predict persistent opioid use: logistic regression, random forest, neural network, balanced random forest, and balanced bagging. Synthetic Minority Oversampling Technique was used to improve class balance. The primary outcome was persistent opioid use, defined as patient reporting to use opioids after 3 months postoperatively. The data were split into a training and test set. Performance metrics were evaluated on the test set and included the F1 score and the area under the receiver operating characteristics curve (AUC). Feature importance was ranked based on SHapley Additive exPlanations (SHAP). RESULTS: After exclusion (patients with missing follow-up data), 2611 patients were included in the analysis, of which 1209 (46.3%) continued to use opioids 3 months after surgery. The balanced random forest classifiers had the highest AUC (0.877, 95% confidence interval [CI], 0.834-0.894) compared to neural networks (0.729, 95% CI, 0.672-0.787), logistic regression (0.709, 95% CI, 0.652-0.767), balanced bagging classifier (0.859, 95% CI, 0.814-0.905), and random forest classifier (0.855, 95% CI, 0.813-0.897). The balanced random forest classifier had the highest F1 (0.758, 95% CI, 0.677-0.839). Furthermore, the specificity, sensitivity, precision, and accuracy were 0.883, 0.700, 0.836, and 0.780, respectively. The features based on SHAP analysis with the highest impact on model performance were age, preoperative opioid use, preoperative pain scores, and body mass index. CONCLUSIONS: The balanced random forest classifier was found to be the most effective model for identifying persistent opioid use after spine surgery.

Public Health Informatics and the Perioperative Physician: Looking to the Future.

The role of informatics in public health has increased over the past few decades, and the coronavirus disease 2019 (COVID-19) pandemic has underscored the critical importance of aggregated, multicenter, high-quality, near-real-time data to inform decision-making by physicians, hospital systems, and governments. Given the impact of the pandemic on perioperative and critical care services (eg, elective procedure delays; information sharing related to interventions in critically ill patients; regional bed-management under crisis conditions), anesthesiologists must recognize and advocate for improved informatic frameworks in their local environments. Most anesthesiologists receive little formal training in public health informatics (PHI) during clinical residency or through continuing medical education. The COVID-19 pandemic demonstrated that this knowledge gap represents a missed opportunity for our specialty to participate in informatics-related, public health-oriented clinical care and policy decision-making. This article briefly outlines the background of PHI, its relevance to perioperative care, and conceives intersections with PHI that could evolve over the next quarter century.

Smallest Clinically Meaningful Improvement in Amputation-Related Pain and Brief Pain Inventory Scores as Defined by Patient Reports of Global Improvement After Cryoneurolysis: a Retrospective Analysis of a Randomized, Controlled Clinical Trial.

BACKGROUND: The smallest meaningful improvement in pain scores (minimal clinically important difference [MCID]) after an analgesic intervention is essential information when both interpreting published data and designing a clinical trial. However, limited information is available for patients with chronic pain conditions, and what is published is derived from studies involving pharmacologic and psychological interventions. We here calculate these values based on data collected from 144 participants of a previously published multicenter clinical trial investigating the effects of a single treatment with percutaneous cryoneurolysis. METHODS: In the original trial, we enrolled patients with a lower-limb amputation and established phantom pain. Each received a single-injection femoral and sciatic nerve block with lidocaine and was subsequently randomized to receive either ultrasound-guided percutaneous cryoneurolysis or sham treatment at these same locations. Investigators, participants, and clinical staff were masked to treatment group assignment with the exception of the treating physician performing the cryoneurolysis, who had no subsequent participant interaction. At both baseline and 4 months (primary end point), participants rated their phantom limb pain based on a numeric rating scale (NRS) and their interference of pain on physical and emotional functioning as measured with the Brief Pain Inventory's interference subscale. They subsequently qualitatively defined the change using the 7-point ordinal Patient Global Impression of Change (PGIC). The smallest clinically meaningful improvements in phantom limb pain and Brief Pain Inventory scores were calculated using an anchor-based method based on the PGIC. RESULTS: The median (interquartile range [IQR]) phantom pain NRS (0-10) improvements at 4 months considered small, medium, and large were 1 [1-1], 3 [3-4], and 4 [3-6], respectively. The median improvements in the Brief Pain Inventory interference subscale (0-70) associated with a small, medium, and large analgesic changes were 16 [6-18], 24 [22-31], and 34 [22-46]. The proportions of patients that experienced PGIC ≥5 were 33% and 36% in the active and placebo groups, respectively. The relative risk of a patient experiencing PGIC ≥5 in the active group compared to the sham group with 95% confidence interval was 0.9 (0.6-1.4), P = .667. CONCLUSIONS: Amputees with phantom limb pain treated with percutaneous cryoneurolysis rate analgesic improvements as clinically meaningful similar to pharmacologic treatments, although their MCID for the Brief Pain Inventory was somewhat larger than previously published values. This information on patient-defined clinically meaningful improvements will facilitate interpretation of available studies and guide future trial design.

A Narrative Review of Ultrasound-Guided and Landmark-based Percutaneous Cryoneurolysis for the Management of Acute and Chronic Pain.

PURPOSE OF REVIEW: Cryoneurolysis refers to the process of reversibly ablating peripheral nerves with extremely cold temperatures to provide analgesia for weeks to months. With ultrasound-guidance or landmark-based techniques, it is an effective modality for managing both acute and chronic pain. In this review, we summarize the reported literature behind its potential applications and efficacy. RECENT FINDINGS: Here, we summarize several studies (from case reports to clinical trials) describing the use of ultrasound-guided and landmark-based cryoneurolysis for acute and chronic pain. Acute pain indications included pain related to knee arthroplasty, limb amputations, mastectomies, shoulder surgery, rib fractures, and burn. Chronic pain indications included chronic knee pain (due to osteoarthritis), shoulder pain, painful neuropathies, postmastectomy pain syndrome, phantom limb pain, facial pain/headaches, foot/ankle pain, inguinal pain, and sacroiliac joint pain. For both acute and chronic pain indications, more high quality randomized controlled clinical trials are needed to definitively assess the efficacy of cryoneurolysis versus other standard therapies for a multitude of pain conditions.

An Interdisciplinary, Comprehensive Recovery Pathway Improves Microsurgical Breast Reconstruction Delivery.

INTRODUCTION: Free-flap (autologous) breast reconstruction demonstrates superiority over alloplastic approaches but is offered infrequently. Enhanced recovery protocols can address postoperative challenges, but most literature is limited to inpatient interventions and outcomes. This study describes an adoptable, longitudinally comprehensive and multidisciplinary recovery pathway for autologous reconstruction which adds to the current guidelines. The authors aimed to allow perioperative outcomes comparable to alloplastic reconstructions. METHODS: All autologous Comprehensive Recovery Pathway (CRP) subjects from a single surgeon were retrospectively included. A comparator group of equal size was randomly selected from institutional subpectoral and dual-plane tissue expander patients having Enhanced Recovery After Surgery guideline-directed care. All subjects in both cohorts received preoperative paravertebral regional blocks. Operative detail, inpatient recovery, longitudinal morphine equivalents (MEs) required, and complications were compared. RESULTS: Each cohort included 71 cases (99 breasts). Despite longer operations, intraoperative MEs were fewer in autologous cases ( P = 0.02). Morphine equivalents during inpatient stay were similar between cohorts, with both being discharged on median day 2. Multivariate regression demonstrated a 0.8-day increased stay for autologous subjects with additional contribution from bilateral cases, body mass index, and age ( P < 0.05). Autologous subjects were regularly discharged postoperative day 1 (17%) and postoperative day 2 (39%), with trend toward earlier discharge ( P < 0.01). Outpatient MEs were significantly fewer in autologous subjects, corresponding to a 30- to 150-mg oxycodone difference ( P < 0.01). Major complication occurred in 12.7% of autologous and 22.5% of alloplastic subjects ( P = 0.11). Flap loss occurred in 1 autologous subject versus 11 alloplastic failures ( P < 0.01). CONCLUSIONS: This study details partnership between the plastic surgery service, regional and acute pain anesthesia services, and dedicated nursing with longitudinal optimizations allowing perioperative outcomes improved over current literature. Patients in the CRP used fewer opioids from operation through follow-up with comparable length of stay and significantly fewer reconstructive failures than alloplastic subjects. The pathway may be quickly adopted into academic practice patterns and mitigates traditional barriers, allowing extension of autologous reconstruction offerings.

Improving case duration accuracy of orthopedic surgery using bidirectional encoder representations from Transformers (BERT) on Radiology Reports.

PURPOSE: A major source of inefficiency in the operating room is the mismatch between scheduled versus actual surgical time. The purpose of this study was to demonstrate a proof-of-concept study for predicting case duration by applying natural language processing (NLP) and machine learning that interpret radiology reports for patients undergoing radius fracture repair. METHODS: Logistic regression, random forest, and feedforward neural networks were tested without NLP and with bag-of-words. Another NLP method tested used feedforward neural networks and Bidirectional Encoder Representations from Transformers specifically pre-trained on clinical notes (ClinicalBERT). A total of 201 cases were included. The data were split into 70% training and 30% test sets. The average root mean squared error (RMSE) were calculated (and 95% confidence interval [CI]) from 10-fold cross-validation on the training set. The models were then tested on the test set to determine proportion of times surgical cases would have scheduled accurately if ClinicalBERT was implemented versus historic averages. RESULTS: The average RMSE was lowest using feedforward neural networks using outputs from ClinicalBERT (25.6 min, 95% CI: 21.5-29.7), which was significantly (P < 0.001) lower than the baseline model (39.3 min, 95% CI: 30.9-47.7). Using the feedforward neural network and ClinicalBERT on the test set, the percentage of accurately predicted cases, which was defined by the actual surgical duration within 15% of the predicted surgical duration, increased from 26.8 to 58.9% (P < 0.001). CONCLUSION: This proof-of-concept study demonstrated the successful application of NLP and machine leaning to extract features from unstructured clinical data resulting in improved prediction accuracy for surgical case duration.

Ultrasound-guided Percutaneous Cryoneurolysis to Treat Chronic Postamputation Phantom Limb Pain: A Multicenter Randomized Controlled Trial.

BACKGROUND: Postamputation phantom pain is notoriously persistent with few validated treatments. Cryoneurolysis involves the application of low temperatures to reversibly ablate peripheral nerves. The authors tested the hypothesis that a single cryoneurolysis treatment would decrease phantom pain 4 months later. METHODS: The authors enrolled patients with a lower-limb amputation and established phantom pain. Each received a single-injection femoral and sciatic nerve block with lidocaine and was subsequently randomized to receive either ultrasound-guided percutaneous cryoneurolysis or sham treatment at these same locations. The primary outcome was the change in average phantom pain intensity between baseline and 4 months as measured with a numeric rating scale (0 to 10), after which an optional crossover treatment was offered. Investigators, participants, and clinical staff were masked to treatment group assignment with the exception of the treating physician performing the cryoneurolysis, who had no subsequent participant interaction. RESULTS: Pretreatment phantom pain scores were similar in both groups, with a median [quartiles] of 5.0 [4.0, 6.0] for active treatment and 5.0 [4.0, 7.0] for sham. After 4 months, pain intensity decreased by 0.5 [-0.5, 3.0] in patients given cryoneurolysis (n = 71) versus 0 [0, 3] in patients given sham (n = 73), with an estimated difference (95% CI) of -0.1 (-1.0 to 0.7), P = 0.759. Following their statistical gatekeeping protocol, the authors did not make inferences or draw conclusions on secondary endpoints. One serious adverse event occurred after a protocol deviation in which a femoral nerve cryolesion was induced just below the inguinal ligament-instead of the sensory-only saphenous nerve-which resulted in quadriceps weakness, and possibly a fall and clavicle fracture. CONCLUSIONS: Percutaneous cryoneurolysis did not decrease chronic lower extremity phantom limb pain 4 months after treatment. However, these results were based upon the authors' specific study protocol, and since the optimal cryoneurolysis treatment parameters such as freeze duration and anatomic treatment location remain unknown, further research is warranted.

A Point-Based Risk Calculator for Mortality After Hepatectomy.

BACKGROUND: Preoperative risk stratification for hepatectomy patients can aid clinical decision making. The objective of this retrospective cohort study was to determine postoperative mortality risk factors and develop a score-based risk calculator using a limited number of preoperative predictors to estimate mortality risk in patients undergoing hepatectomy. METHODS: Data were collected from patients that underwent hepatectomy from the National Surgical Quality Improvement Program dataset from 2014 to 2020. Baseline characteristics were compared between survival and 30-day mortality cohorts using the χ 2 test. Next, the data were split into a training set to build the model and a test set to validate the model. A multivariable logistic regression model modeling 30-day postoperative mortality was trained on the training set using all available features. Next, a risk calculator using preoperative features was developed for 30-day mortality. The results of this model were converted into a score-based risk calculator. A point-based risk calculator was developed that predicted 30-day postoperative mortality in patients who underwent hepatectomy surgery. RESULTS: The final dataset included 38,561 patients who underwent hepatectomy. The data were then split into a training set from 2014 to 2018 (n = 26,397) and test set from 2019 to 2020 (n = 12,164). Nine independent variables associated with postoperative mortality were identified and included age, diabetes, sex, sodium, albumin, bilirubin, serum glutamic-oxaloacetic transaminase (SGOT), international normalized ratio, and American Society of Anesthesiologists classification score. Each of these features were then assigned points for a risk calculator based on their odds ratio. A univariate logistic regression model using total points as independent variables were trained on the training set and then validated on the test set. The area under the receiver operating characteristics curve on the test set was 0.719 (95% confidence interval, 0.681-0.757). CONCLUSIONS: Development of risk calculators may potentially allow surgical and anesthesia providers to provide a more transparent plan to support patients planned for hepatectomy.

Racial and Ethnic Differences in the Receipt of Regional Anesthesia Among Patients Undergoing Thoracic Surgery.

OBJECTIVES: The objective of this study was to assess differences in the use of perioperative regional anesthesia for thoracic surgery based on race and ethnicity. DESIGN: This retrospective cohort study used data from the American College of Surgeons National Surgical Quality Improvement Program from 2015 to 2020. The study authors applied a multivariate logistic regression in which the dependent variable was the primary endpoint (regional versus no regional anesthesia). The primary independent variables were race and ethnicity. SETTING: Multiple healthcare systems in the United States. PARTICIPANTS: Participants were ≥18 years of age and undergoing thoracic surgery. INTERVENTIONS: Regional anesthesia. MEASUREMENTS AND MAIN RESULTS: On adjusted multivariate analysis, Hispanic patients had lower odds (odds ratio [OR] 0.61, 95% CI 0.46-0.80, p = 0.0003) of receiving regional anesthesia for postoperative pain control compared to non-Hispanic patients. There was no significant difference in the odds of regional anesthesia when comparing racial cohorts (ie, White, Black, Asian, or other). CONCLUSIONS: There were differences observed in the provision of regional anesthesia for thoracic surgery among ethnic groups. Although the results of this study should not be taken as evidence for healthcare disparities, it could be used to support hypotheses for future studies that aim to investigate causes of disparities and corresponding patient outcomes.

Racial and Ethnic Differences in the Use of Regional Anesthesia for Patients Undergoing Total Knee Arthroplasty.

BACKGROUND: There is an increasing body of evidence that suggests racial and ethnic disparities exist in medical care. In the field of anesthesiology, few studies have investigated the association of race and ethnicity with the provision of regional anesthesia for patients undergoing total knee arthroplasty. This analysis queried a large national surgical database to determine whether there were racial or ethnic differences in the administration of peripheral nerve blocks for patients undergoing total knee arthroplasty. METHODS: In this retrospective cohort study, data were collected from a large national database during the years 2017-2019. Multivariable logistic regressions were used to measure the association of race and ethnicity with utilization of regional anesthesia. The participants for the study were patients 18 years or older undergoing total knee arthroplasty. RESULTS: Our primary finding was that among patients undergoing total knee arthroplasty, Black patients had lower odds (adjusted odds ratio [aOR]: 0.93, 99% confidence interval [CI]: 0.89-0.98) of receiving regional anesthesia than White patients. Also, Hispanic patients had lower odds (aOR: 0.88, 99% CI: 0.83-0.94) of receiving regional anesthesia than non-Hispanic patients. Native Hawaiian/Pacific Islander patients had increased odds (aOR: 2.04, 99% CI: 1.66-2.51) of receiving regional anesthesia. CONCLUSION: This study demonstrated that there might be racial and ethnic differences in the provision of regional anesthesia for patients undergoing total knee arthroplasty. These differences underscore the need for more studies aimed at equitable access to high quality and culturally competent health care.

Spinal Cord Stimulator (SCS) Placement: Examining Outcomes Between the Open and Percutaneous Approach.

BACKGROUND: Spinal cord stimulator (SCS) placement has been gaining traction as an approach to modulate pain levels for several different chronic pain conditions. This procedure can be performed via a percutaneous or open approach. Data regarding SCS complications are relatively limited. OBJECTIVE: The purpose of this study was to leverage a large national database to examine outcomes between the percutaneous and open SCS placement approaches. Outcomes in this study include length of stay (LOS), complication rates, reoperation rates, and 1-year readmission rates. MATERIALS AND METHODS: Inclusion criteria for the current study is SCS placement between 2015 and 2020, with receipt of an SCS using either a percutaneous approach or an open laminectomy based approach. Encounters included were limited to true SCS placement, such that trial placements were not included in the study. Univariate statistics and multivariable logistic regression was performed to compare outcomes between cohorts. RESULTS: Total SCS case volumes were 9935 between the percutaneous (n = 4477, 45.1%) and open (n = 5458, 54.9%) approach. Patients receiving the percutaneous approach were found to have a mean decrease in LOS of 9.91 hours when compared to those receiving the open approach. The percutaneous approach was significantly associated with the need for reoperation within one year compared to the open approach (odds ratio [OR]: 0.663, p < 0.001), as well as with the need for readmission within 30 days (51.2% vs 40.2%, OR: 0.759, p < 0.001). CONCLUSION: The open approach, when compared to the percutaneous approach, had a longer mean LOS, lower outpatient discharge rates, and higher odds of experiencing an operative complication in comparison to the percutaneous approach. The percutaneous approach had relatively increased odds of thirty-day readmission, although no significant difference in one-year readmission or removal was demonstrated.

The Association of Psychiatric Comorbidities With Short-Term and Long-Term Outcomes Following Spinal Cord Stimulator Placement.

BACKGROUND: Outcomes after spinal cord stimulator (SCS) placement are affected by psychologic comorbidities. It is part of routine practice to do psychologic assessments prior to SCS trials to assess for the presence of maladaptive behavioral patterns. However, few studies have sought to quantify the effect of psychiatric comorbidities on complications, reoperation, and readmission rates. The purpose of this study was to assess the association of psychiatric comorbidities with postprocedural outcomes after SCS implantation. MATERIALS AND METHODS: Inclusion criteria included SCS placement between 2015 and 2020 (percutaneous approach or an open laminectomy-based approach) using Healthcare Corporation of America National Database. Data on psychiatric comorbidities present at the time of SCS implantation surgery were collected. Outcomes of interest included complication rates (defined as lead migration, fracture, malfunction, battery failure, postoperative pain, infection, dural puncture, or neurological injury), reoperation rates (defined as either revision or explant [ie, removal]), and readmission rates within 30-day and 1-year time after SCS implantation. We measured the association between psychiatric comorbidities and outcomes using multivariable regression and reported odds ratio (OR) and respective 95% confidence intervals. RESULTS: A total of 12,751 cases were included. The most common psychiatric comorbidities were major depressive disorder (16.1%) and anxiety disorder (13.4%). In unadjusted univariate analysis, patients with any psychiatric comorbidity had heightened rates of any complication (27.1% vs 19.4%), infection (5.9% vs 1.9%), lead displacement (2.2% vs 1.3%), surgical pain (2.1% vs 1.2%), explant (14.7% vs 8.8%), and readmission rates at one year (54.2% vs 33.8%) (all p < 0.001). In multivariable logistic regression, with each additional psychiatric comorbidity, a patient had increased odds of experiencing any complication (OR = 1.5, 95% CI = 1.36-1.57, p < 0.001), requiring a reoperation (OR = 1.5, 95% CI = 1.37-1.6, p < 0.001), and requiring readmission (OR = 1.7, 99% CI = 1.6-1.8, p < 0.001). CONCLUSIONS: The presence of psychiatric comorbidities was found to be associated with postoperative complication rates, reoperation, and readmission rates after SCS placement. Furthermore, each consecutive increase in psychiatric comorbidity burden was associated with increased odds of complications, reoperation, and readmission. Future studies might consider examining the role of presurgical mental health screening (ie, patient selection, psychologic testing) and treatment in optimizing outcomes for patients with psychiatric comorbidities.

A Retrospective Analysis Investigating Whether Case Volume Experience of the Anesthesiologist Correlates with Intraoperative Efficiency for Joint Arthroplasty.

The objective of this retrospective study was to determine if there was an association between anesthesiology experience (e.g. historic case volume) and operating room (OR) efficiency times for lower extremity joint arthroplasty cases. The primary outcome was time from patient in the OR to anesthesia ready (i.e. after spinal or general anesthesia induction was complete). The secondary outcomes included time from anesthesia ready to surgical incision, and time from incision to closing completed. Mixed effects linear regression was performed, in which the random effect was the anesthesiology attending provider. There were 4,575 patients undergoing hip or knee arthroplasty included. There were 82 unique anesthesiology providers, in which the median [quartile] frequency of cases performed was 79 [45, 165]. On multivariable mixed effects linear regression - in which the primary independent variable (anesthesiologist case volume history for joint arthroplasty anesthesia) was log-transformed - the estimate for log-transformed case volume was - 0.91 (95% confidence interval [CI] -1.62, -0.20, P = 0.01). When modeling time from incision to closure complete, the estimate for log-transformed case volume was - 2.07 (95% -3.54, -0.06, P = 0.01). Thus, when comparing anesthesiologists with median case volume (79 cases) versus those with the lowest case volume (10 cases), the predicted difference in times added up to only approximately 6 min. If the purpose of faster anesthesia workflows was to open up more OR time to increase surgical volume in a given day, this study does not support the supposition that anesthesiologists with higher joint arthroplasty case volume would improve throughput.

Machine Learning Prediction Models to Reduce Length of Stay at Ambulatory Surgery Centers Through Case Resequencing.

The post-anesthesia care unit (PACU) length of stay is an important perioperative efficiency metric. The aim of this study was to develop machine learning models to predict ambulatory surgery patients at risk for prolonged PACU length of stay - using only pre-operatively identified factors - and then to simulate the effectiveness in reducing the need for after-hours PACU staffing. Several machine learning classifier models were built to predict prolonged PACU length of stay (defined as PACU stay ≥ 3 hours) on a training set. A case resequencing exercise was then performed on the test set, in which historic cases were re-sequenced based on the predicted risk for prolonged PACU length of stay. The frequency of patients remaining in the PACU after-hours (≥ 7:00 pm) were compared between the simulated operating days versus actual operating room days. There were 10,928 ambulatory surgical patients included in the analysis, of which 580 (5.31%) had a PACU length of stay ≥ 3 hours. XGBoost with SMOTE performed the best (AUC = 0.712). The case resequencing exercise utilizing the XGBoost model resulted in an over three-fold improvement in the number of days in which patients would be in the PACU past 7pm as compared with historic performance (41% versus 12%, P<0.0001). Predictive models using preoperative patient characteristics may allow for optimized case sequencing, which may mitigate the effects of prolonged PACU lengths of stay on after-hours staffing utilization.

Wearable, noninvasive, pulsed shortwave (radiofrequency) therapy for analgesia and opioid sparing following outpatient surgery: A proof-of-concept case series.

BACKGROUND: It is often difficult to concurrently provide adequate analgesia while minimizing opioid requirements following ambulatory surgery. Nonthermal, pulsed shortwave (radiofrequency) fields are a noninvasive treatment used as an adjunct analgesic and wound healing therapy. The devices may be placed by nursing staff in less than a minute, are relatively inexpensive and readily available, theoretically provide analgesia for nearly any anatomic location, and have no systemic side effects-patients cannot detect any sensations from the devices-or significant risks. Here we present a case series to demonstrate the use of pulsed, electromagnetic field devices for outpatient herniorrhaphy and breast surgery. CASE REPORT: Following moderately painful ambulatory umbilical (n = 3) and inguinal (n = 2) hernia repair as well as bilateral breast surgery (n = 2), patients had taped over their surgical incision(s) 1 or 2 noninvasive, wearable, disposable, pulsed shortwave therapy devices (RecoveryRx, BioElectronics Corporation, Frederick, Maryland) which functioned continuously for 30 days. Average resting pain scores measured on the 0-10 numeric rating scale were a median of 0 during the entire treatment period. Six patients avoided opioid use entirely, while the remaining individual required only 5 mg of oxycodone during the first postoperative day. CONCLUSIONS: These cases demonstrate that the ambulatory use of pulsed shortwave devices is feasible and may be an effective analgesic, possibly obviating opioid requirements following outpatient herniorrhaphy and breast surgery. Considering the lack of any side effects, adverse events, and misuse/dependence/diversion potential, further study with a randomized, controlled trial appears warranted.

Preoperative Ultrasound-guided Percutaneous Cryoneurolysis for the Treatment of Pain after Mastectomy: A Randomized, Participant- and Observer-masked, Sham-controlled Study.

BACKGROUND: Ultrasound-guided percutaneous cryoneurolysis is an analgesic technique in which a percutaneous probe is used to reversibly ablate a peripheral nerve(s) using exceptionally low temperature, and has yet to be evaluated with randomized, controlled trials. Pain after mastectomy can be difficult to treat, and the authors hypothesized that the severity of surgically related pain would be lower on postoperative day 2 with the addition of cryoanalgesia compared with patients receiving solely standard-of-care treatment. METHODS: Preoperatively, participants at one enrolling center received a single injection of ropivacaine, 0.5%, paravertebral nerve block at T3 or T4, and perineural catheter. Participants subsequently underwent an active or sham ultrasound-guided percutaneous cryoneurolysis procedure of the ipsilateral T2 to T5 intercostal nerves in a randomized, patient- and observer-masked fashion. Participants all received a continuous paravertebral block with ropivacaine, 0.2%, until the early morning of discharge (usually postoperative day 2). The primary endpoint was the average pain level measured using a 0 to 10 numeric rating scale the afternoon of postoperative day 2. Participants were followed for 1 yr. RESULTS: On postoperative day 2, participants who had received active cryoneurolysis (n = 31) had a median [interquartile range] pain score of 0 [0 to 1.4] versus 3.0 [2.0 to 5.0] in patients given sham (n = 29): difference -2.5 (97.5% CI, -3.5 to -1.5), P < 0.001. There was evidence of superior analgesia through month 12. During the first 3 weeks, cryoneurolysis lowered cumulative opioid use by 98%, with the active group using 1.5 [0 to 14] mg of oxycodone compared with 72 [20 to 120] mg in the sham group (P < 0.001). No oral analgesics were required by any patient between months 1 and 12. After 1 yr chronic pain had developed in 1 (3%) active compared with 5 (17%) sham participants (P < 0.001). CONCLUSIONS: Percutaneous cryoneurolysis markedly improved analgesia without systemic side effects or complications after mastectomy.

Basal Infusion versus Automated Boluses and a Delayed Start Timer for "Continuous" Sciatic Nerve Blocks after Ambulatory Foot and Ankle Surgery: A Randomized Clinical Trial.

BACKGROUND: The common technique using a basal infusion for an ambulatory continuous peripheral nerve blocks frequently results in exhaustion of the local anesthetic reservoir before resolution of surgical pain. This study was designed to improve and prolong analgesia by delaying initiation using an integrated timer and delivering a lower hourly volume of local anesthetic as automated boluses. The hypothesis was that compared with a traditional continuous infusion, ropivacaine administered with automated boluses at a lower dose and 5-h delay would (1) provide at least noninferior analgesia (difference in average pain no greater than 1.7 points) while both techniques were functioning (average pain score day after surgery) and (2) result in a longer duration (dual primary outcomes). METHODS: Participants (n = 70) undergoing foot or ankle surgery with a popliteal-sciatic catheter received an injection of ropivacaine 0.5% with epinephrine (20 ml) and then were randomized to receive ropivacaine (0.2%) either as continuous infusion (6 ml/h) initiated before discharge or as automated boluses (8 ml every 2 h) initiated 5 h after discharge using a timer. Both groups could self-deliver supplemental boluses (4 ml, lockout 30 min); participants and outcome assessors were blinded to randomization. All randomized participants were included in the data analysis. RESULTS: The day after surgery, participants with automated boluses had a median [interquartile range] pain score of 0.0 [0.0 to 3.0] versus 3.0 [1.8 to 4.8] for the continuous infusion group, with an odds ratio of 3.1 (95% CI, 1.23 to 7.84; P = 0.033) adjusting for body mass index. Reservoir exhaustion in the automated boluses group occurred after a median [interquartile range] of 119 h [109 to 125] versus 74 h [57 to 80] for the continuous infusion group (difference of 47 h; 95% CI, 38 to 55; P < 0.001 adjusting for body mass index). CONCLUSIONS: For popliteal-sciatic catheters, replacing a continuous infusion initiated before discharge with automated boluses and a start-delay timer resulted in better analgesia and longer infusion duration.