Do Hounsfield Units From Intraoperative CT Scans Correlate With Preoperative Values?

BACKGROUND: There is increasing interest in forecasting postoperative complications using bone density metrics. Vertebral Hounsfield unit measurements obtained from CT scans performed for surgical planning or other purposes, known as opportunistic CTs, have shown promise for their ease of measurement and the ability to target density measurement to a particular region of interest. Concomitant with the rising interest in prognostic bone density measurement use has been the increasing adoption of intraoperative advanced imaging techniques. Despite the interest in both outcome prognostication and intraoperative advanced imaging, there is little information regarding the use of CT-based intraoperative imaging as a means to measure bone density. QUESTIONS/PURPOSES: (1) Can vertebral Hounsfield units be reliably measured by physician reviewers from CT scans obtained intraoperatively? (2) Do Hounsfield units measured from intraoperative studies correlate with values measured from preoperative CT scans? METHODS: To be eligible for this retrospective study, patients had to have been treated with the use of an intraoperative CT scan for instrumented spinal fusion for either degenerative conditions or traumatic injuries between January 2015 and December 2022. Importantly, patients without a preoperative CT scan of the fused levels within 180 days before surgery or who were indicated for surgery because of infection, metastatic disease, or who were having revision surgery after prior instrumentation were excluded from the query. Of the 285 patients meeting these inclusion criteria, 53% (151) were initially excluded for the following reasons: 36% (102) had intraoperative CT scans obtained after placement of instrumentation, 16% (47) had undergone intraoperative CT scans but the studies were not accessible for Hounsfield unit measurement, and 0.7% (2) had prior kyphoplasty wherein the cement prevented Hounsfield unit measurement. Finally, an additional 19% (53) of patients were excluded because the preoperative CT and intraoperative CT were obtained at different peak voltages, which can influence Hounsfield unit measurement. This yielded a final population of 81 patients from whom 276 preoperative and 276 intraoperative vertebral Hounsfield unit measurements were taken. Hounsfield unit data were abstracted from the same vertebra(e) from both preoperative and intraoperative studies by two physician reviewers (one PGY3 and one PGY5 orthopaedic surgery resident, both pursuing spine surgery fellowships). For a small, representative subset of patients, measurements were taken by both reviewers. The feasibility and reliability of Hounsfield unit measurement were then assessed with interrater reliability of values measured from the same vertebra by the two different reviewers. To compare Hounsfield unit values from intraoperative CT scans with preoperative CT studies, an intraclass correlation using a two-way random effects, absolute agreement testing technique was employed. Because the data were formatted as multiple measurements from the same vertebra at different times, a repeated measures correlation was used to assess the relationship between preoperative and intraoperative Hounsfield unit values. Finally, a linear mixed model with patients handled as a random effect was used to control for different patient and clinical factors (age, BMI, use of bone density modifying agents, American Society of Anesthesiologists [ASA] classification, smoking status, and total Charlson comorbidity index [CCI] score). RESULTS: We found that Hounsfield units can be reliably measured from intraoperative CT scans by human raters with good concordance. Hounsfield unit measurements of 31 vertebrae from a representative sample of 10 patients, measured by both reviewers, demonstrated a correlation value of 0.82 (95% CI 0.66 to 0.91), indicating good correlation. With regard to the relationship between preoperative and intraoperative measurements of the same vertebra, repeated measures correlation testing demonstrated no correlation between preoperative and intraoperative measurements (r = 0.01 [95% CI -0.13 to 0.15]; p = 0.84). When controlling for patient and clinical factors, we continued to observe no relationship between preoperative and intraoperative Hounsfield unit measurements. CONCLUSION: As intraoperative CT and measurement of vertebral Hounsfield units both become increasingly popular, it would be a natural extension for spine surgeons to try to extract Hounsfield unit data from intraoperative CTs. However, we found that although it is feasible to measure Hounsfield data from intraoperative CT scans, the obtained values do not have any predictable relationship with values obtained from preoperative studies, and thus, these values should not be used interchangeably. With this knowledge, future studies should explore the prognostic value of intraoperative Hounsfield unit measurements as a distinct entity from preoperative measurements. LEVEL OF EVIDENCE: Level III, diagnostic study.

Primary Care Physician Preferences Regarding Communication from Orthopaedic Surgeons.

BACKGROUND: Musculoskeletal consultations constitute a growing portion of primary care physician (PCP) referrals. Optimizing communication between PCPs and orthopaedists can potentially reduce time spent in the electronic medical record (EMR) as well as physician burnout. Little is known about the preferences of PCPs regarding communication from orthopaedic surgeons. Hence, the present study investigated, across a large health network, the preferences of PCPs regarding communication from orthopaedists. METHODS: A total of 175 PCPs across 15 practices within our health network were surveyed. These providers universally utilized Epic as their EMR platform. Five-point, labeled Likert scales were utilized to assess the PCP-perceived importance of communication from orthopaedists in specific clinical scenarios. PCPs were further asked to report their preferred method of communication in each scenario and their overall interest in communication from orthopaedists. Logistic regression analyses were performed to determine whether any PCP characteristics were associated with the preferred method of communication and the overall PCP interest in communication from orthopaedists. RESULTS: A total of 107 PCPs (61.1%) responded to the survey. PCPs most commonly rated communication from orthopaedists as highly important in the scenario of an orthopaedist needing information from the PCP. In this scenario, PCPs preferred to receive an Epic Staff Message. Scenarios involving a recommendation for surgery, hospitalization, or a major clinical change were also rated as highly important. In these scenarios, an Epic CC'd Chart rather than a Staff Message was preferred. Increased after-hours EMR use was associated with diminished odds of having a high interest in communication from orthopaedists (odds ratio, 0.65; 95% confidence interval, 0.48 to 0.88; p = 0.005). Ninety-three PCPs (86.9%) reported spending 1 to 1.5 hours or more per day in Epic after normal clinical hours, and 27 (25.2%) spent >3 hours per day. Forty-six PCPs (43.0%) reported experiencing ≥1 symptom of burnout. CONCLUSIONS: There were distinct preferences among PCPs regarding clinical communication from orthopaedic surgeons. There was also evidence of substantial burnout and after-hours work effort by PCPs. These results may help to optimize communication between PCPs and orthopaedists while reducing the amount of time that PCPs spend in the EMR.

The utility of vertebral Hounsfield units as a prognostic indicator of adverse events following treatment of spinal epidural abscess.

Background: Spinal epidural abscesses (SEAs) are a devastating condition with high levels of associated morbidity and mortality. Hounsfield units (HUs), a marker of radiodensity on CT scans, have previously been correlated with adverse events following spinal interventions. We evaluated whether HUs might also be associated with all-cause complications and/or mortality in this high-risk population. Methods: This retrospective cohort study was carried out within an academic health system in the United States. Adults diagnosed with a SEA between 2006 and 2021 and who also had a CT scan characterizing their SEA within 6 months of diagnosis were considered. HUs were abstracted from the 4 vertebral bodies nearest to, but not including, the infected levels. Our primary outcome was the presence of composite 90-day complications and HUs represented the primary predictor. A multivariable logistic regression analysis was conducted adjusting for demographic and disease-specific confounders. In sensitivity testing, separate logistic regression analyses were conducted (1) in patients aged 65 and older and (2) with mortality as the primary outcome. Results: Our cohort consisted of 399 patients. The overall incidence of 90-day complications was 61.2% (n=244), with a 7.8% (n=31) 90-day mortality rate. Those experiencing complications were more likely to have undergone surgery to treat their SEA (58.6% vs. 46.5%; p=.018) but otherwise the cohorts were similar. HUs were not associated with composite 90-day complications (Odds ratio [OR] 1.00 [95% CI 1.00-1.00]; p=.842). Similar findings were noted in sensitivity testing. Conclusions: While HUs have previously been correlated with adverse events in certain clinical contexts, we found no evidence to suggest that HUs are associated with all-cause complications or mortality in patients with SEAs. Future research hoping to leverage 3-dimensional imaging as a prognostic measure in this patient population should focus on alternative targets. Level of Evidence: Level III; Observational Cohort study.

Intraoperative navigation increases the projected lifetime cancer risk in patients undergoing surgery for adolescent idiopathic scoliosis.

BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) is a common condition, often requiring surgical correction. Computed tomography (CT) based navigation technologies, which rely on ionizing radiation, are increasingly being utilized for surgical treatment. Although this population is highly vulnerable to radiation, given their age and female predominance, there is little available information elucidating modeled iatrogenic cancer risk. PURPOSE: To model lifetime cancer risk associated with the use of intraoperative CT-based navigation for surgical treatment of AIS. STUDY DESIGN/SETTING: This retrospective cross-sectional study took place in a quaternary care academic pediatric hospital in the United States. PATIENT SAMPLE: Adolescents aged 10-18 who underwent posterior spinal fusion for a diagnosis of AIS between July 2014 and December 2019. OUTCOMES MEASURES: Effective radiation dose and projected lifetime cancer risk associated with intraoperative doses of ionizing radiation. METHODS: Clinical and radiographic parameters were abstracted, including total radiation dose during surgery from flat plate radiographs, fluoroscopy, and intraoperative CT scans. Multivariable regression analysis was used to assess differences in radiation exposure between patients treated with conventional radiography versus intraoperative navigation. Radiation exposure was translated into lifetime cancer risk using well-established algorithms. RESULTS: In total, 245 patients were included, 119 of whom were treated with navigation. The cohort was 82.9% female and 14.4 years of age. The median radiation exposure (in millisieverts, mSv) for fluoroscopy, radiography, and navigation was 0.05, 4.14, and 8.19 mSv, respectively. When accounting for clinical and radiographic differences, patients treated with intraoperative navigation received 8.18 mSv more radiation (95%CI: 7.22-9.15, p<.001). This increase in radiation projects to 0.90 iatrogenic malignancies per 1,000 patients (95%CI 0.79-1.01). CONCLUSIONS: Ours is the first work to define cancer risk in the setting of radiation exposure for navigated AIS surgery. We project that intraoperative navigation will generate approximately one iatrogenic malignancy for every 1,000 patients treated. Given that spine surgery for AIS is common and occurs in the context of a multitude of other radiation sources, these data highlight the need for radiation budgeting protocols and continued development of lower radiation dose technologies. LEVEL OF EVIDENCE: Therapeutic, III.

The Use of the Lateral Tibial Line to Assess Ankle Alignment: A Preliminary Investigation.

BACKGROUND: Although the medial clear space (MCS) is commonly used to assess talar alignment and ankle stability, its measurement is variable with multiple reported normal values. We have observed that the lateral tibial shaft is a reliable landmark to assess talar alignment. The objective of the current investigation was to determine the normal relationship of the lateral tibia to the superolateral talus using a tangent drawn inferiorly from the lateral tibial shaft, which we refer to as the "lateral tibial line" (LTL). METHODS: The relationship of the LTL to the superolateral talus was assessed by three reviewers on 99 standing ankle mortise radiographs in uninjured patients. This relationship was quantified by measuring the distance (in millimeters) between the LTL and the superolateral talus. In addition, the interobserver reliability of the LTL measurement was recorded and compared with that of the MCS. RESULTS: The median value for the distance between the superolateral talus and LTL was -0.50 mm with an interquartile range of -1.4 to 0.0 mm. The LTL was within 1 mm of the lateral talus in 176 of 297 reviewer measurements (59.3%). Moreover, it was either lateral to or at most 1 mm medial to the lateral talus in 90.9% of cases. The LTL measurement also demonstrated good interobserver reliability (0.764, 95% confidence interval, 0.670 to 0.834), similar to the measurement of MCS (0.742, 95% confidence interval, 0.539 to 0.846). CONCLUSIONS: The relationship between the LTL and superolateral talus is easily measured with good reliability for assessing the anatomic relationship of the tibia and talus. The LTL uncommonly fell more than 1 mm medial to the superolateral talus, as might be seen with displaced ankle fractures. These findings will hopefully serve as a basis for future studies evaluating its role in assessing lateral displacement and stability of isolated fibula fractures. LEVEL OF EVIDENCE: Level III, retrospective review.

Validation of the Stopping Opioids After Surgery (SOS) Score for the Sustained Use of Prescription Opioids Following Orthopaedic Surgery.

BACKGROUND: The Stopping Opioids after Surgery (SOS) score was developed to identify patients at risk for sustained opioid use following surgery. The SOS score has not been specifically validated for patients in a general orthopaedic context. Our primary objective was to validate the SOS score within this context. METHODS: In this retrospective cohort study, we considered a broad array of representative orthopaedic procedures performed between January 1, 2018, and March 31, 2022. These procedures included rotator cuff repair, lumbar discectomy, lumbar fusion, total knee and total hip arthroplasty, open reduction and internal fixation (ORIF) of ankle fracture, ORIF of distal radial fracture, and anterior cruciate ligament reconstruction. The performance of the SOS score was evaluated by calculating the c-statistic, receiver operating characteristic curve, and the observed rates of sustained prescription opioid use (defined as uninterrupted prescriptions of opioids for ≥90 days) following surgery. For our sensitivity analysis, we compared these metrics among various time epochs related to the COVID-19 pandemic. RESULTS: A total of 26,114 patients were included, of whom 51.6% were female and 78.1% were White. The median age was 63 years. The observed prevalence of sustained opioid use was 1.3% (95% confidence interval [CI], 1.2% to 1.5%) in the low-risk group (SOS score of <30), 7.4% (95% CI, 6.9% to 8.0%) in the medium-risk group (SOS score of 30 to 60), and 20.8% (95% CI, 17.7% to 24.2%) in the high-risk group (SOS score of >60). The performance of the SOS score in the overall group was strong, with a c-statistic of 0.82. The performance of the SOS score showed no evidence of worsening over time. The c-statistic was 0.79 before the COVID-19 pandemic and ranged from 0.77 to 0.80 throughout the waves of the pandemic. CONCLUSIONS: We validated the use of the SOS score for sustained prescription opioid use following a diverse array of orthopaedic procedures across subspecialties. This tool is easy to implement for the purpose of prospectively identifying patients in musculoskeletal service lines who are at higher risk for sustained opioid use, thereby enabling the future implementation of upstream interventions and modifications to avert opioid abuse and to combat the opioid epidemic. LEVEL OF EVIDENCE: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Neurological Outcomes and the Need for Retreatments Among Multiple Myeloma Patients With High-Grade Spinal Cord Compression: Radiotherapy vs Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: Up to 30% of Multiple Myeloma (MM) patients are expected to experience Epidural Spinal Cord Compression (ESCC) during the course of their disease. To prevent irreversible neurological damage, timely diagnosis and treatment are important. However, debate remains regarding the optimal treatment regimen. The aim of this study was to investigate the neurological outcomes and frequency of retreatments for MM patients undergoing isolated radiotherapy and surgical interventions for high-grade (grade 2-3) ESCC. METHODS: This study included patients with MM and high-grade ESCC treated with isolated radiotherapy or surgery. Pre- and post-treatment American Spinal Injury Association (ASIA) impairment scale and retreatment rate were compared between the 2 groups. Adjusted multivariable logistic regression was utilized to examine differences in neurologic compromise, pain, and retreatments. RESULTS: A total of 247 patients were included (Radiotherapy: n = 154; Surgery: n = 93). After radiotherapy, 82 patients (53%) achieved full neurologic function (ASIA E) at the end of follow-up. Of the surgically treated patients, 67 (64%) achieved full neurologic function. In adjusted analyses, patients treated with surgery were less likely to experience neurologic deterioration within 2 years (OR = .15; 95%CI .05-.44; P = .001) and had less pain (OR = .29; 95%CI .11-.74; P = .010). Surgical treatment was not associated with an increased risk of retreatments (OR = .64; 95%CI .28-1.47; P = .29) or death (HR = .62, 95%CI .28-1.38; P = .24). CONCLUSIONS: After adjusting for baseline differences, surgically treated patients with high-grade ESCC showed better neurologic outcomes compared to patients treated with radiotherapy. There were no differences in risk of retreatment or death.

Does the Stopping Opioids After Surgery Score Perform Well Among Racial and Socioeconomic Subgroups?

BACKGROUND: The Stopping Opioids After Surgery (SOS) score is a validated tool that was developed to determine the risk of sustained opioid use after surgical interventions, including orthopaedic procedures. Despite prior investigations validating the SOS score in diverse contexts, its performance across racial, ethnic, and socioeconomic subgroups has not been assessed. QUESTIONS/PURPOSES: In a large, urban, academic health network, did the performance of the SOS score differ depending on (1) race and ethnicity or (2) socioeconomic status? METHODS: This retrospective investigation was conducted using data from an internal, longitudinally maintained registry of a large, urban, academic health system in the Northeastern United States. Between January 1, 2018, and March 31, 2022, we treated 26,732 adult patients via rotator cuff repair, lumbar discectomy, lumbar fusion, TKA, THA, ankle or distal radius open reduction and internal fixation, or ACL reconstruction. We excluded 1% of patients (274 of 26,732) because of missing length of stay information, 0.06% (15) for missing discharge information, 1% (310) for missing medication information related to loss to follow-up, and 0.07% (19) who died during their hospital stay. Based on these inclusion and exclusion criteria, 26,114 adult patients were left for analysis. The median age in our cohort was 63 years (IQR 52 to 71), and most patients were women (52% [13,462 of 26,114]). Most patients self-reported their race and ethnicity as non-Hispanic White (78% [20,408 of 26,114]), but the cohort also included non-Hispanic Black (4% [939]), non-Hispanic Asian (2% [638]), and Hispanic (1% [365]) patients. Five percent (1295) of patients were of low socioeconomic status, defined by prior SOS score investigations as patients with Medicaid insurance. Components of the SOS score and the observed frequency of sustained postoperative opioid prescriptions were abstracted. The performance of the SOS score was compared across racial, ethnic, and socioeconomic subgroups using the c-statistic, which measures the capacity of the model to differentiate between patients with and without sustained opioid use. This measure should be interpreted on a scale between 0 and 1, where 0 represents a model that perfectly predicts the wrong classification, 0.5 represents performance no better than chance, and 1.0 represents perfect discrimination. Scores less than 0.7 are generally considered poor. The baseline performance of the SOS score in past investigations has ranged from 0.76 to 0.80. RESULTS: The c-statistic for non-Hispanic White patients was 0.79 (95% CI 0.78 to 0.81), which fell within the range of past investigations. The SOS score performed worse for Hispanic patients (c-statistic 0.66 [95% CI 0.52 to 0.79]; p < 0.001), where it tended to overestimate patients' risks of sustained opioid use. The SOS score for non-Hispanic Asian patients did not perform worse than in the White patient population (c-statistic 0.79 [95% CI 0.67 to 0.90]; p = 0.65). Similarly, the degree of overlapping CIs suggests that the SOS score did not perform worse in the non-Hispanic Black population (c-statistic 0.75 [95% CI 0.69 to 0.81]; p = 0.003). There was no difference in score performance among socioeconomic groups (c-statistic 0.79 [95% CI 0.74 to 0.83] for socioeconomically disadvantaged patients; 0.78 [95% CI 0.77 to 0.80] for patients who were not socioeconomically disadvantaged; p = 0.92). CONCLUSION: The SOS score performed adequately for non-Hispanic White patients but performed worse for Hispanic patients, where the 95% CI nearly included an area under the curve value of 0.5, suggesting that the tool is no better than chance at predicting sustained opioid use for Hispanic patients. In the Hispanic population, it commonly overestimated the risk of opioid dependence. Its performance did not differ among patients of different sociodemographic backgrounds. Future studies might seek to contextualize why the SOS score overestimates expected opioid prescriptions for Hispanic patients and how the utility performs among more specific Hispanic subgroups. CLINICAL RELEVANCE: The SOS score is a valuable tool in ongoing efforts to combat the opioid epidemic; however, disparities exist in terms of its clinical applicability. Based on this analysis, the SOS score should not be used for Hispanic patients. Additionally, we provide a framework for how other predictive models should be tested in various lesser-represented populations before implementation.

Spinal artery syndrome following kyphoplasty in the setting of a non-compressive extradural cement extravasation: a case report.

INTRODUCTION: Cement extravasation (CE) during vertebroplasty or kyphoplasty for vertebral compression fracture (VCF) is not uncommon, though neurological deficits occur rarely and when paraparesis occurs severe cord compression has been described. We report a case of progressive paraparesis in the setting of non-compressive extradural CE during kyphoplasty with evidence for spinal artery syndrome and neurological recovery after treatment. CASE PRESENTATION: A 77-year-old female with T12 VCF failed conservative treatment and underwent kyphoplasty. In the recovery room, the patient was noted to have bilateral leg weakness, left worse than right, and had urgent CT scan that showed right paracentral CE without cord compression or arterial cement embolization. The patient was transferred to a tertiary hospital and had MRI of the spine that confirmed extradural CE and no cord compression. Because the patient had progression of lower extremity deficits despite medical management, she underwent surgical decompression, cement excision, and spinal fusion with instrumentation. Post op MRI showed T2 hyperintensities in the spinal cord consistent with spinal artery syndrome. One month post op, she had almost complete recovery of her neurological function. DISCUSSION: Spinal artery syndrome may be considered in patients with neurological deficit s/p kyphoplasty even if the extravasated cement does not compress the spinal cord and even if the deficits are worse contralateral to the cement extravasation. If spinal artery syndrome is present and medical management does not improve the deficits, surgery may be indicated even if there is no cord compression.

Projected Lifetime Cancer Risk Associated With Intraoperative Computed Tomography for Lumbar Spine Surgery.

STUDY DESIGN: Retrospective cross-sectional study. OBJECTIVE: (1) To determine the incremental increase in intraoperative ionizing radiation conferred by computed tomography (CT) as compared with conventional radiography; and (2) to model different lifetime cancer risks contextualized by the intersection between age, sex, and intraoperative imaging modality. SUMMARY OF BACKGROUND DATA: Emerging technologies in spine surgery, like navigation, automation, and augmented reality, commonly utilize intraoperative CT. Although much has been written about the benefits of such imaging modalities, the inherent risk profile of increasing intraoperative CT has not been well evaluated. MATERIALS AND METHODS: Effective doses of intraoperative ionizing radiation were extracted from 610 adult patients who underwent single-level instrumented fusion for lumbar degenerative or isthmic spondylolisthesis from January 2015 through January 2022. Patients were divided into those who received intraoperative CT (n=138) and those who underwent conventional intraoperative radiography (n=472). Generalized linear modeling was utilized with intraoperative CT use as a primary predictor and patient demographics, disease characteristics, and preference-sensitive intraoperative considerations ( e.g. surgical approach and surgical invasiveness) as covariates. The adjusted risk difference in radiation dose calculated from our regression analysis was used to prognosticate the associated cancer risk across age and sex strata. RESULTS: (1) After adjusting for covariates, intraoperative CT was associated with 7.6 mSv (interquartile range: 6.8-8.4 mSv; P <0.001) more radiation than conventional radiography. (2) For the median patient in our population (a 62-year-old female), intraoperative CT use increased lifetime cancer risk by 2.3 incidents (interquartile range: 2.1-2.6) per 10,000. Similar projections for other age and sex strata were also appreciated. CONCLUSIONS: Intraoperative CT use significantly increases cancer risk compared with conventional intraoperative radiography for patients undergoing lumbar spinal fusions. As emerging technologies in spine surgery continue to proliferate and leverage intraoperative CT for cross-sectional imaging data, strategies must be developed by surgeons, institutions, and medical technology companies to mitigate long-term cancer risks.

Intraoperative CT for lumbar fusion is not associated with improved short- or long-term complication profiles.

BACKGROUND CONTEXT: The use of intraoperative CT has continued to grow in recent years, as various techniques leverage the promise of improved instrumentation accuracy and the hope for decreased complications. Nonetheless, the literature regarding the short- and long-term complications associated with such techniques remains scant and/or confounded by indication and selection bias. PURPOSE: To use causal inference techniques to determine whether intraoperative CT use is associated with an improved complication profile as compared to conventional radiography for single-level lumbar fusions, an increasingly commonplace application for this technology. STUDY DESIGN/SETTING: Inverse probability weighted retrospective cohort study carried out within a large integrated health care network. PATIENT SAMPLE: Adult patients who underwent surgical treatment of spondylolisthesis via lumbar fusion from January 2016 to December 2021. OUTCOME MEASURES: Our primary outcome was the incidence rate of revision surgery. Our secondary outcome was the incidence of composite 90-day complications (deep and superficial surgical site infection, venous thromboembolic events, and unplanned readmissions). METHODS: Demographics, intraoperative information, and postoperative complications were abstracted from electronic health records. A propensity score was developed utilizing a parsimonious model to account for covariate interaction with our primary predictor, intraoperative imaging technique. This propensity score was utilized in the creation of inverse probability weights to adjust for indication and selection bias. The rate of revisions within 3 years as well as the rate of revisions at any time-point were compared between cohorts using Cox regression analysis. The incidence of composite 90-day complications were compared using negative binomial regression. RESULTS: Our patient population consisted of 583 patients, with 132 who underwent intraoperative CT and 451 who underwent conventional radiographic techniques. There were no significant differences between cohorts following inverse probability weighting. No significant differences were detected in 3-year revision rates (HR, 0.74 [95% CI 0.29, 1.92]; p=.5), overall revision rates (HR, 0.54 [95% CI 0.20, 1.46]; p=.2), or 90-day complications (RC -0.24 [95% CI -1.35, 0.87]; p=.7). CONCLUSIONS: Intraoperative CT use was not associated with an improved complication profile in either the short- or long-term for patients undergoing single-level instrumented fusion. This observed clinical equipoise should be weighed against resource and radiation-related costs when considering intraoperative CT for low complexity fusions.

Thoracolumbar Injury Classification Systems: The Importance of Concepts and Language in the Move Toward Standardization.

STUDY DESIGN: Narrative review. OBJECTIVE: To describe the evolution of acute traumatic thoracolumbar (TL) injury classification systems; to promote standardization of concepts and vocabulary with respect to TL injuries. SUMMARY OF BACKGROUND DATA: Over the past century, numerous TL classification systems have been proposed and implemented, each influenced by the thought, imaging modalities, and surgical techniques available at the time. While much progress has been made in our understanding and management of these injuries, concepts, and terms are often intermixed, leading to potential confusion and miscommunication. METHODS: We present a narrative review of the current state of the literature regarding classification systems for TL trauma. RESULTS: The evolution of TL classification systems has broadly been characterized by a transition away from descriptive categorizations of fracture patterns to schema incorporating morphology, stability, and neurological function. In addition to these features, more recent systems have demonstrated the importance of predictive/prognostic capability, reliability, validity, and generalizability. The Arbeitsgemeinschaft fur Osteosynthesenfragen Spine Thoracolumbar Injury Classification System/Thoracolumbar Arbeitsgemeinschaft fur Osteosynthesenfragen Spine Injury Score represents the most modern and recently updated system, retiring past concepts and terminology in favor of clear, internationally agreed upon descriptors. CONCLUSIONS: Advancements in our understanding of blunt TL trauma injuries have led to changes in management. Such advances are reflected in modern, dedicated classification systems. Over time, various key factors have been acknowledged and incorporated. In an effort to promote standardization of thought and language, past ideas and terminology should be retired.

Projected lifetime cancer risk for patients undergoing spine surgery for isthmic spondylolisthesis.

BACKGROUND CONTEXT: Radiographs, fluoroscopy, and computed tomography (CT) are increasingly utilized in the diagnosis and management of various spine pathologies. Such modalities utilize ionizing radiation, a known cause of carcinogenesis. While the radiation doses such studies confer has been investigated previously, it is less clear how such doses translate to projected cancer risks, which may be a more interpretable metric. PURPOSE: (1) Calculate the lifetime cancer risk and the relative contributions of preference-sensitive selection of imaging modalities associated with the surgical management of a common spine pathology, isthmic spondylolisthesis (IS); (2) Investigate whether the use of intraoperative CT, which is being more pervasively adopted, increases the risk of cancer. STUDY DESIGN/SETTING: Retrospective cross-sectional study carried out within a large integrated health care network. PATIENT SAMPLE: Adult patients who underwent surgical treatment of IS via lumbar fusion from January 2016 through December 2021. OUTCOME MEASURES: (1) Effective radiation dose and lifetime cancer risk associated with each exposure to ionizing radiation; (2) Difference in effective radiation dose (and lifetime cancer risk) among patients who received intraoperative CT compared to other intraoperative imaging techniques. METHODS: Baseline demographics and differences in surgical techniques were characterized. Radiation exposure data were collected from the 2-year period centered on the operative date. Projected risk of cancer from this radiation was calculated utilizing each patient's effective radiation dose in combination with age and sex. Generalized linear modeling was used to adjust for covariates when determining the comparative risk of intraoperative CT as compared to alternative imaging modalities. RESULTS: We included 151 patients in this cohort. The range in calculated cancer risk exclusively from IS management was 1.3-13 cases of cancer per 1,000 patients. During the intraoperative period, CT imaging was found to significantly increase radiation exposure as compared to alternate imaging modalities (adjusted risk difference (ARD) 12.33mSv; IQR 10.04, 14.63mSv; p<.001). For a standardized 40 to 49-year-old female, this projects to an additional 0.72 cases of cancer per 1,000. For the entire 2-year perioperative care episode, intraoperative CT as compared to other intraoperative imaging techniques was not found to increase total ionizing radiation exposure (ARD 9.49mSv; IQR -0.83, 19.81mSv; p=.072). The effect of intraoperative imaging choice was mitigated in part due to preoperative (ARD 13.1mSv, p<.001) and postoperative CTs (ARD 22.7mSv, p<.001). CONCLUSIONS: Preference-sensitive imaging decisions in the treatment of IS impart substantial cancer risk. Important drivers of radiation exposure exist in each phase of care, including intraoperative CT and/or CT scans during the perioperative period. Knowledge of these data warrant re-evaluation of current imaging protocols and suggest a need for the development of radiation-sensitive approaches to perioperative imaging.

The epidemiology and management of iliopsoas hematoma with femoral nerve palsy: A descriptive systematic review of 174 cases.

INTRODUCTION: Iliopsoas hematoma with femoral nerve palsy is a rare phenomenon with no consensus treatment algorithm. The objective of this study was to perform a systematic review of all reported cases of femoral nerve palsy secondary to iliopsoas hematoma to better elucidate it's optimal treatment. MATERIALS AND METHODS: Queries of the PubMed, Embase, and Cochrane databases were performed for reports available in English of femoral nerve palsy secondary to iliopsoas, psoas, or iliacus hematoma. 1491 articles were identified. After removal of duplicated publications and review of abstract titles via a majority reviewer consensus, 217 articles remained for consideration. Dedicated review of the remaining articles (including their reference sections) yielded 122 articles representing 174 distinct cases. Clinical data including patient age, sex, medical history, use of pharmacologic anticoagulation, sensory and motor examination at presentation and follow-up, hematoma etiology and location, time to intervention, and type of intervention were collected. Descriptive statistics were generated for each variable. RESULTS: Femoral nerve palsy secondary to iliopsoas hematoma occurred at a mean age of 44.5 years old. A majority of patients (60%) were male, and a majority of hematomas (54%) occurred due to pharmacologic anticoagulation. Most hematomas (57%) were treated conservatively, and almost half (49%) - regardless of treatment modality - resulted in persistent motor deficits at final follow-up. A minority of patients treated surgically (34%) had residual motor deficit at final follow-up, while 66% of those treated medically had resultant motor deficits, although no direct statistical comparison was able to be performed. DISCUSSION AND CONCLUSIONS: The disparate available data on iliopsoas hematoma with femoral nerve palsy precludes the completion of a true metanalysis, and therefore any conclusions on an optimal treatment algorithm. Based on review of the literature, small to moderate hematomas are often treated conservatively, while larger hematomas with progressive neurological symptoms are usually managed with a percutaneous decompression or surgery. LEVEL OF EVIDENCE: IV.

Strategies reducing risk of surgical-site infection following pediatric spinal deformity surgery.

BACKGROUND: Identifying beneficial preventive strategies for surgical-site infection (SSI) in individual patients with different clinical and surgical characteristics is challenging. The purpose of this study was to investigate the association between preventive strategies and patient risk of SSI taking into consideration baseline risks and estimating the reduction of SSI probability in individual patients attributed to these strategies. METHODS: Pediatric patients who underwent primary, revision, or final fusion for their spinal deformity at 7 institutions between 2004 and 2018 were included. Preventive strategies included the use of topical vancomycin, bone graft, povidone-iodine (PI) irrigations, multilayered closure, impermeable dressing, enrollment in quality improvement (QI) programs, and adherence to antibiotic prophylaxis. The CDC definition of SSI as occurring within 90 days postoperatively was used. Multiple regression modeling was performed following multiple imputation and multicollinearity testing to investigate the effect of preventive strategies on SSI in individual patients adjusted for patient and surgical characteristics. RESULTS: Univariable regressions demonstrated that enrollment in QI programs and PI irrigation were significantly associated, and topical vancomycin, multilayered closure, and correct intraoperative dosing of antibiotics trended toward association with reduction of SSI. In the final prediction model using multiple regression, enrollment in QI programs remained significant and PI irrigation had an effect in decreasing risks of SSI by average of 49% and 18%, respectively, at the individual patient level. CONCLUSION: Considering baseline patient characteristics and predetermined surgical and hospital factors, enrollment in QI programs and PI irrigation reduce the risk of SSI in individual patients. Multidisciplinary efforts should be made to implement these practices to increase patient safety. LEVEL OF EVIDENCE: Prognostic level III study.

The Future of Spine Care Innovation-Software not Hardware: How the Digital Transformation Will Change Spine Care Delivery.

STUDY DESIGN: Narrative review. OBJECTIVE: The aim was to utilize the lessons from the digital transformation of industries beyond healthcare, weigh the changing forces within the healthcare ecosystem, and provide a framework for the likely state of spine care delivery in the future. SUMMARY OF BACKGROUND DATA: Advances in technology have transformed the way in which we as consumers interact with most products and services, driven by devices, platforms, and a dramatic increase in the availability of digital data. Spine care delivery, and much of healthcare in general, has lagged far behind, hamstrung by regulatory limitations, narrow data networks, limited digital platforms, and cultural attachment to legacy care delivery models. METHODS: The authors present a narrative review of the current state of the spine field in this dynamic and evolving environment. RESULTS: The past several decades of spine innovation have largely been driven by "hardware" improvements, such as instrumentation, devices, and enabling technologies to facilitate procedures. These changes, while numerous, have largely resulted in modest incremental improvements in clinical outcomes. The next phase of growth in spine care, however, is likely to be more reflective of the broader innovation ecosystem that has already transformed most other industries, characterized by improvements in "software," including: (1) leveraging data analytics with growing electronic health records databases to optimize interactions between patients and providers, (2) expanding digital and telemedicine platforms to create integrated hybrid service lines, (3) data modeling for patient and provider decision aids, (4) deploying provider and service line performance metrics to improve quality, and (5) movement toward more free market dynamics as patients increasingly move beyond legacy limited health system networks. CONCLUSION: Spine care stakeholders should familiarize themselves with the concepts discussed in this review, as they create value for patients and are also likely to dramatically shift the spine care delivery landscape.

Surgical Intervention is Associated With Improvements in the ASIA Impairment Scale in Gunshot-induced Spinal Injuries of the Thoracic and Lumbar Spine.

STUDY DESIGN: Retrospective cohort study of patients from the National Spinal Cord Injury Statistical Center (NSCISC). OBJECTIVE: The aim was to compare the outcomes of patients with gunshot-induced spinal injuries (GSIs) treated operatively and nonoperatively. SUMMARY OF BACKGROUND DATA: The treatment of neurological deficits associated with gunshot wounds to the spine has been controversial. Treatment has varied widely, ranging from nonoperative to aggressive surgery. METHODS: Patient demographics, clinical information, and outcomes were extracted. Surgical intervention was defined as a "laminectomy, neural canal restoration, open reduction, spinal fusion, or internal fixation of the spine." The primary outcome was the American Spinal Injury Association (ASIA) Impairment Scale. Statistical comparisons of baseline demographics and neurological outcomes between operative and nonoperative cohorts were performed. RESULTS: In total, 961 patients with GSI and at least 1-year follow-up were identified from 1975 to 2015. The majority of patients were Black/African American (55.6%), male (89.7%), and 15-29 years old (73.8%). Of those treated surgically (19.7% of all patients), 34.2% had improvement in their ASIA Impairment Scale score at 1 year, compared with 20.6% treated nonoperatively. Overall, surgery was associated with a 2.0 [95% confidence interval (CI): 1.4-2.8] times greater likelihood of ASIA Impairment Scale improvement at 1 year. Specifically, benefit was seen in thoracic (odds ratio: 2.5; 95% CI: 1.4-4.6) and lumbar injuries (odds ratio: 1.7; 95% CI: 1.1-3.1), but not cervical injuries. CONCLUSIONS: While surgical indications are always determined on an individualized basis, in our review of GSIs, surgical intervention was associated with a greater likelihood of neurological recovery. Specifically, patients with thoracic and lumbar GSIs had a 2.5 and 1.7-times greater likelihood of improvement in their ASIA Impairment Scale score 1 year after injury, respectively, if they underwent surgical intervention.

ALIF Versus TLIF for L5-S1 Isthmic Spondylolisthesis: ALIF Demonstrates Superior Segmental and Regional Radiographic Outcomes and Clinical Improvements Across More Patient-reported Outcome Measures Domains.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose of this study was to compare segmental and regional radiographic parameters between anterior interbody fusion (ALIF) and posterior interbody fusion (TLIF) for treatment of L5-S1 isthmic spondylolisthesis, and to assess for changes in these parameters over time. Secondarily, we sought to compare clinical outcomes via patient-reported outcome measures (PROMs) between techniques and within groups over time. SUMMARY OF BACKGROUND DATA: Isthmic spondylolistheses are frequently treated with interbody fusion via ALIF or TLIF approaches. Robust comparisons of radiographic and clinical outcomes are lacking. METHODS: We reviewed pre- and postoperative radiographs as well as Patient-Reported Outcomes Measurement Information System (PROMIS) elements for patients who received L5-S1 interbody fusions for isthmic spondylolisthesis in the Mass General Brigham (MGB) health system (2016-2020). Intraclass correlation testing was used for reliability assessments; Mann-Whitney U tests and Sign tests were employed for intercohort and intracohort comparative analyses, respectively. RESULTS: ALIFs generated greater segmental and L4-S1 lordosis than TLIF, both at first postoperative visit (mean 26 days [SE = 4]; 11.3° vs. 1.3°, P  < 0.001; 6.2° vs. 0.3°, P  = 0.005) and at final follow-up (mean 410days [SE = 45]; 9.6° vs. 0.2°, P < 0.001; 7.9° vs. 2.1°, P = 0.005). ALIF also demonstrated greater increase in disc height than TLIF at first (9.6 vs. 5.5 mm, P < 0.001) and final follow-up (8.7 vs. 3.6 mm, P < 0.001). Disc height was maintained in the ALIF group but decreased over time in the TLIF cohort (ALIF 9.6 vs. 8.7 mm, P = 0.1; TLIF 5.5 vs. 3.6 mm, P < 0.001). Both groups demonstrated improvements in Pain Intensity and Pain Interference scores; ALIF patients also improved in Physical Function and Global Health - Physical domains. CONCLUSION: ALIF generates greater segmental lordosis, regional lordosis, and restoration of disc height compared to TLIF for treatment of isthmic spondylolisthesis. Additionally, ALIF patients demonstrate significant improvements across more PROMs domains relative to TLIF patients.Level of Evidence: 3.

Early Weight Bearing after Distal Femur Fracture Fixation.

OBJECTIVES: To assess outcomes following early weight bearing after distal femur fracture fixation with locked lateral plating. DESIGN: Retrospective cohort study. SETTING: Two Level 1 Academic Trauma Centers. PATIENTS/PARTICIPANTS: Patients 18 years and older with distal femur fractures treated with locked lateral plating. INTERVENTION: Early full weight bearing (defined as less than 30 days from date of surgery) versus restricted post-operative weight bearing. MAIN OUTCOME MEASUREMENTS: Composite complication comprising malunion, nonunion, surgical site infection, re-admission, or death. RESULTS: 270 distal femur fractures were reviewed, with 165 meeting inclusion criteria. 21 patients had been allowed early full weight bearing. Fractures were divided into two groups based on when full weight bearing was allowed post-operatively. The two groups had similar fractures as determined by the distribution of AO distal femur fracture and Su periprosthetic femur fracture classifications. The early weight bearing group was significantly older and more comorbid. Despite being older, more comorbid, and allowed early full weight bearing on their fracture fixation construct, there was no difference in the rate of composite complications between groups. CONCLUSION: Our data contributes to the small, but growing body of literature that has found no increased rate of fracture related complications in surgically treated distal femur fractures allowed early post-operative weight bearing. LEVEL OF EVIDENCE: Therapeutic Level III Study.