Vertebral Artery Variation and Imposed Risks Associated with Anterior Cervical Discectomy and Fusion Procedures - A Case Study with Surgeons' Perspectives.

Introduction: Anterior cervical discectomy and fusion (ACDF) is a common cervical procedure with more than 137,000 cases in the United States (U.S.) each year. Historically, ACDF has been a relatively safe procedure despite encountering vital anatomical structures that can risk serious complications. One particularly dangerous sequela of ACDF is the risk of lacerating the vertebral artery (VA). While VA injuries are rare (0.5% of cases), it is crucial for surgeons to prevent this potentially deadly complication with thorough knowledge of VA anatomy. The VA is commonly protected within the transverse foreman; however, anomalies can exist with the artery potentially being found more medial or proximal within the surgical site than expected. The purpose of this article is to report an anomaly found in a cadaveric specimen, where the VA courses within 2 mm of an ACDF plate. Case Report: A 66-year-old male with a past medical history of coronary artery disease passed away due to complications of a myocardial infarction. During cadaveric dissection, it was discovered that the donor had undergone a previous 3-level (C4-C7) ACDF procedure for an unknown reason. Under further examination, the left VA was observed to take an anomalous medially tracking course before eventually entering the transverse foramina of C5. Left anterior tubercles were absent at the level of C5 and C6 with prominent osteophytes found on the anterior tubercles/transverse foramina of the contralateral side. Conclusion: There are no studies published on the anatomy of VA variants and their implications on ACDF procedures. ACDF was found to have complication rates in 13.2% of cases. VA variants are observed in up to 20% of the U.S. population and VA injury in ACDF procedures has a rate near 0.5%. With anatomic variations leading to a higher risk of injury, surgeons are required to take further precautionary steps before operating including ordering computed tomography angiography or magnetic resonance angiography films. Understanding the detailed anatomy of the VA and its variants is critical. Using the perspectives of orthopedic spine surgeons, this study supplements the literature on potential VA anomalies encountered in ACDF procedures.

Inferior Vena Cava Filter Retrieval Rates Associated With Passive and Active Surveillance Strategies Adopted by Implanting Physicians.

Importance: Inferior vena cava filters are commonly implanted and infrequently retrieved. Nonretrieval contributes to significant morbidity, motivating US Food and Drug Administration and multisociety communications emphasizing the need for improved device surveillance. Current guidelines suggest that implanting physicians and referring physicians should be responsible for device follow-up, but it is not known whether shared responsibility contributes to lower retrieval. Objective: To determine if primary responsibility for follow-up care assumed by the implanting physician team is associated with increased device retrieval. Design, Setting, and Participants: This retrospective cohort study examined a prospectively collected registry of patients with inferior vena cava filters implanted from June 2011 to September 2019. Medical record review and data analysis was completed in 2021. The study included 699 patients who underwent implantation of retrievable inferior vena cava filters at an academic quaternary care center. Exposures: Prior to 2016, implanting physicians had a passive surveillance strategy whereby letters highlighting indications for and the need for timely retrieval were mailed to patients and ordering clinicians. Starting in 2016, implanting physicians assumed active responsibility for surveillance, whereby candidacy for device retrieval was assessed periodically via phone calls and retrieval scheduled when appropriate. Main Outcomes and Measures: The main outcome was the odds of inferior vena cava filter nonretrieval. Within regression modeling of the association between the surveillance method and nonretrieval, additional covariates of patient demographics, concomitant malignant neoplasm, and presence of thromboembolic disease were included. Results: Of the 699 patients who received retrievable filter implants, 386 (55.2%) were followed up with passive surveillance, 313 (44.8%) with active surveillance, 346 (49.5%) were female, 100 (14.3%) were Black individuals, and 502 (71.8%) were White individuals. The mean (SD) age at filter implantation was 57.1 (16.0) years. Mean (SD) yearly filter retrieval increased following the adoption of active surveillance, from 190 of 386 (48.7%) to 192 of 313 (61.3%) (P < .001). Fewer filters were deemed permanent in the active group vs passive group (5 of 313 [1.6%] vs 47 of 386 [12.2%]; P < .001). Age at the time of implantation (OR, 1.02; 95% CI, 1.01-1.03), concomitant malignant neoplasm (OR, 2.18; 95% CI, 1.47-3.24), and passive contact method (OR, 1.70; 95% CI, 1.18-2.47) were associated with increased odds of filter nonretrieval. Conclusions and Relevance: The findings of this cohort study suggest that active surveillance by implanting physicians is associated with improved inferior vena cava filter retrieval. These findings support encouraging physicians who implant the filter to take primary responsibility for tracking and retrieval.

Thrombus Signal on T1-Weighted Black-Blood MR Predicts Outcomes of Catheter-Directed Thrombolysis in Acute Deep Vein Thrombosis.

OBJECTIVES: Catheter-directed thrombolysis (CDT) is an effective therapy for acute deep vein thrombosis (DVT). However, predicting the CDT outcomes remains elusive. We hypothesized that the thrombus signal on T1-weighted black-blood magnetic resonance (MR) can provide insight into CDT outcomes in acute DVT patients. METHODS: A total of 117 patients with acute iliofemoral DVT were enrolled for T1-weighted black-blood MR before CDT in this prospective study. Based on the signal contrast between thrombus and adjacent muscle, patients were categorized into the iso-intense thrombus (Iso-IT), hyper-intense thrombus (Hyper-IT), and mixed iso-/hyper-intense thrombi (Mixed-IT) groups. Immediate treatment outcome (i.e., vein patency) and long-term treatment outcome (i.e., the incidence rate of postthrombotic syndrome) were accessed by the same expert. Histological analysis and iron quantification were performed on thrombus samples to characterize the content of fibrin, collagen, and the ratio of Fe3+ to total iron. RESULTS: Compared to Mixed-IT and Hyper-IT groups, the Iso-IT group had the best lytic effect (90.5 ± 1.6% vs. 78.4 ± 2.6% vs. 46.5 ± 3.3%, p < 0.001), lowest bleeding ratio (0.0 vs. 11.8 vs. 13.3, p < 0.001), and the lowest incidence rate of postthrombotic syndrome on 24 months (3.6 vs. 18.4 vs. 63.4%, p < 0.001) following CDT. The Iso-IT group had a significantly lower ratio of Fe3+ to total iron (93.1 ± 3.2% vs. 97.2 ± 2.1%, p = 0.034) and a higher content of fibrin (12.5 ± 5.3% vs. 4.76 ± 3.18%, p = 0.023) than Hyper-IT. CONCLUSION: Thrombus signal characteristics on T1-weighted black-blood MR is associated with CDT outcomes and possesses potential to serve as a noninvasive approach to guide treatment decision making in acute DVT patients. KEY POINTS: · Thrombus signal on T1-weighted black-blood MR is associated with lytic therapeutic outcome in acute DVT patients.. · Presence of iso-intense thrombus revealed by T1-weighted black-blood MRI is associated with successful thrombolysis, low bleeding ratio, and low incidence of the postthrombotic syndrome.. · T1-weighted thrombus signal characteristics may serve as a noninvasive imaging marker to predict CDT treatment outcomes and therefore guide treatment decision making in acute DVT patients..

Estimating Thrombus Elasticity by Shear Wave Elastography to Evaluate Ultrasound Thrombolysis for Thrombus With Different Stiffness.

OBJECTIVE: There is uncertainty about deep vein thrombosis standard treatment as thrombus stiffness alters each case. Here, we investigated thrombus' stiffness of different compositions and ages using shear wave elastography (SWE). We then studied the effectiveness of ultrasound-thrombolysis on different thrombus compositions. METHODS: Shear waves generated through mechanical shaker and traveled along thrombus of different hematocrit (HCT) levels, whereas 18-MHz ultrasound array used to detect wave propagation. Thrombus' stiffness was identified by the shear wave speed (SWS). In thrombolysis, a 3.2 MHz focused transducer was applied to different thrombus compositions using different powers. The thrombolysis rate was defined as the percentage of weight loss. RESULTS: The estimated average SWS of 20%, 40%, and 60% HCT thrombus were 0.75 m/s, 0.44 m/s, and 0.32 m/s, respectively. For Thrombolysis, the percentage weight loss at 8 MPa Negative pressure for the same HCT groups were 23.1%, 35.29%, and 39.66% respectively. CONCLUSION: SWS is inversely related to HCT level and positively related to thrombus age. High HCT thrombus had higher weight loss compared to low HCT. However, the difference between 20% and 40% HCT was more significant than between 40% and 60% HCT in both studies. Our results suggest that thrombus with higher SWS require more power to achieve the same thrombolysis rate as thrombus with lower SWS. SIGNIFICANCE: Characterizing thrombus elastic property undergoing thrombolysis enables evaluation of ultrasound efficacy for fractionating thrombus and reveals the appropriate ultrasound parameters selection to achieve a certain thrombolysis rate in the case of a specific thrombus stiffness.

Safety and Success Rates of Excimer Laser Sheath-Assisted Retrieval of Embedded Inferior Vena Cava Filters.

Importance: Despite historically high rates of use, most inferior vena cava (IVC) filters are not retrieved. The US Food and Drug Administration safety communications recommended retrieval when the IVC filter is no longer indicated out of concern for filter-related complications. However, failure rates are high when using standard techniques for retrieval of long-dwelling filters, and until recently, there have been no devices approved for retrieval of embedded IVC filters. Objective: To evaluate the safety and success of excimer laser sheath-assisted retrieval of embedded IVC filters. Design, Setting, and Participants: A retrospective, multicenter, clinical cohort study of excimer laser sheath-assisted IVC filter retrievals from 7 US sites was conducted between March 1, 2012, and February 28, 2021, among 265 patients who underwent IVC filter retrieval using the laser. Patients were substratified between a high-volume single center and a multicenter data set. A blinded physician committee adjudicated reported complications and their association with use of the laser. Exposures: Retrieval of IVC filters using excimer laser sheath. Main Outcomes and Measures: The primary safety end point was device-related major complication rate (Society of Interventional Radiology categories C to F, which included any adverse event associated with morbidity or disability that increases the level of care, results in hospital admission, or substantially lengthens the hospital stay). The primary success end point was technical success of IVC filter retrieval. The primary end points were compared with literature-derived, meta-analysis-suggested target performance goals. Results: The single-center experience included 139 participants (mean [SD] age, 52 [16] years; 78 female participants [56.1%]), and the multicenter experience included 126 participants (mean [SD] age, 52 [16] years; 75 female participants [59.5%]). The device-related major complication rate was 2.9% (4 of 139; 95% CI, 0.8%-7.2%; P = .001) for the single-center experience and 4.0% (5 of 126; 95% CI, 1.3%-9.0%; P = .01) for the multicenter experience, both of which were significantly lower than the primary safety performance goal (10%). No major complications were considered to be definitively associated with use of the laser. The technical success rate was 95.7% (133 of 139; 95% CI, 90.8%-98.4%; P = .007) for the single-center experience and 95.2% (120 of 126; 95% CI, 89.9%-98.2%; P = .02) for the multicenter experience, both of which were significantly higher than the primary performance goal (89.4%). Conclusions and Relevance: This cohort study demonstrated high technical success and low complication rates of excimer laser sheath-assisted retrieval of embedded IVC filters in centers with variable case volume and experience, which suggests a wide applicability of the technique with proper training. The excimer laser sheath offers physicians a valuable tool for retrieval of challenging embedded IVC filters.

High Prevalence of Transjugular Intrahepatic Portosystemic Shunt Creation Without Prior Endoscopy During Acute Variceal Bleeding Hospitalization in the United States.

Current clinical guidelines by both American Association for the Study of Liver Disease and European Association for the Study of the Liver recommend endoscopy in all patients admitted with acute variceal bleeding within 12 hours of admission. Transjugular intrahepatic portosystemic shunt (TIPS) creation may be considered in patients at high risk if hemorrhage cannot be controlled endoscopically. We conducted a cross-sectional observational study to assess how frequently TIPS is created for acute variceal bleeding in the United States without preceding endoscopy. Adult patients undergoing TIPS creation for acute variceal bleeding in the United States (n = 6,297) were identified in the last 10 available years (2007-2016) of the National Inpatient Sample. Hierarchical logistic regression was used to examine the relationship between endoscopy nonutilization and hospital characteristics, controlling for patient demographics, income level, insurance type, and disease severity. Of 6,297 discharges following TIPS creation for acute variceal bleeding in the United States, 31% (n = 1,924) did not receive first-line endoscopy during the same encounter. Rates of "no endoscopy" decreased with increasing population density of the hospital county (nonmicropolitan counties 43%, n = 114; mid-size metropolitan county 35%, n = 513; and central county with >1 million population 23%, n = 527) but not by hospital teaching status (n = 1,465, 32% teaching vs. n = 430, 26% nonteaching; P = 0.10). Higher disease mortality risk (odds ratio, 0.42; 95% confidence interval, 0.22-0.80; P = 0.02) was associated with lower odds of noncompliance. Conclusion: One third of all patients undergoing TIPS creation for acute variceal bleeding in the United States do not receive first-line endoscopy during the same encounter. Patients admitted to urban hospitals are more likely to receive guideline-concordant care.

Robotic-Assisted Versus Conventional Posterior Lumbar Fusion-An Analysis of 90-Day Complications and Readmissions.

OBJECTIVE: To evaluate medical and surgical complication rates between robotic-assisted versus conventional elective posterior lumbar fusions. METHODS: The Symphony Integrated DataVerse was queried using International Classification of Diseases, 10th Edition, Clinical Modification procedure codes to identify patients undergoing elective posterior lumbar fusions for degenerative spine pathologies between 2015 and 2018. International Classification of Diseases, 10th Edition, Clinical Modification procedure codes (8E0W4CZ, 8E0W0CZ, 8E0W3CZ) were used to identify patients undergoing a robotic-assisted spinal fusion. Outcome measures were 90-day medical and surgical complications, 1-year pseudarthrosis, and 1-year revision surgery rates. Multivariate logistic regression analyses were used to assess whether undergoing a robotic-assisted fusion (vs. conventional fusion) was associated with differences in wound complications, medical complications, pseudarthrosis, revision surgery, and readmissions within 90 days of surgery. RESULTS: A total of 39,387 patients undergoing elective posterior lumbar fusions were included in the cohort-of whom 245 (0.62%) patients underwent a robotic-assisted fusion. Multivariate analysis showed that robotic-assisted fusion (vs. conventional fusion) was not associated with significant differences in 90-day rates of wound complications (P = 0.299), urinary tract infections (P = 0.648), acute myocardial infarctions (P = 0.209), acute renal failure (P = 0.461), pneumonia (P = 0.214), stroke (P = 0.917), deep venous thrombosis (P = 0.562), pulmonary embolism (P = 0.401), and readmissions (P = 0.985). In addition, there were no significant differences in the 1-year rates of revision fusions (P = 0.316) and pseudarthrosis (P = 0.695). CONCLUSIONS: Patients who underwent a robotic-assisted fusion had similar rates of surgical and medical complications compared with those who underwent a conventional fusion. Further studies are warranted to better understand the future role of robots in spine surgery.

Comparative efficacy and safety of the Captus device for inferior vena cava filter retrieval.

PURPOSE: Retrievable inferior vena cava filters (IVCF) have been increasingly used for mechanical pulmonary embolism prophylaxis since their development. The Captus Vascular Retrieval System (Avantec Vascular, Sunnyvale, California) is a new device developed for retrieval of IVCF. This study compared the safety and efficacy of the new Captus device against the existing EnSnare Endovascular Snare System (Merit Medical, South Jordan, Utah) for IVCF retrieval. METHODS: Patients undergoing IVCF retrieval at a single institution between July 2015 and July 2020 were retrospectively identified. All adult patients (>18 years) undergoing filter retrieval with either Captus or Ensnare were included. Technical success and complications were compared by device. A complexity score was assigned to each case to adjust for selection bias. Logistic regression was used to model the association between device type and primary technical success. RESULTS: 99 IVCF retrievals met inclusion criteria, 59 with Captus and 40 with Ensnare. The majority of the cohort consisted of low complexity cases (n = 51, 86% Captus versus n = 31, 78% Ensnare; p = 0.28). Technical success for low and medium complexity retrievals was 88% and 62% with Captus and 96% and 33% with Ensnare. There was no significant association between device type and technical success, adjusting for case complexity (Captus OR 0.55, 95% CI 0.08-2.72, p = 0.49). There were no device-related complications. CONCLUSION: No statistically significant difference in device technical success or complications between the Ensnare and Captus devices for uncomplicated IVCF retrieval. PRECIS: The Captus Vascular Retrieval System is a new device for IVC filter retrieval which has similar technical success to the existing EnSnare.

Ethnoracial Disparity in Hospital Survival following Transjugular Intrahepatic Portosystemic Shunt Creation for Acute Variceal Bleeding in the United States.

PURPOSE: To investigate the magnitude of racial/ethnic differences in hospital mortality after transjugular intrahepatic portosystemic shunt (TIPS) creation for acute variceal bleeding and whether hospital care processes contribute to them. METHODS: Patients aged ≥18 years undergoing TIPS creation for acute variceal bleeding in the United States (n = 10,331) were identified from 10 years (2007-2016) available in the National Inpatient Sample. Hierarchical logistic regression was used to examine the relationship between patient race and inpatient mortality, controlling for disease severity, treatment utilization, and hospital characteristics. RESULTS: A total of 6,350 (62%) patients were White, 1,780 (17%) were Hispanic, and 482 (5%) were Black. A greater proportion of Black patients were admitted to urban teaching hospitals (Black, n = 409 (85%); Hispanic, n = 1,310 (74%); and White, n = 4,802 (76%); P < .001) and liver transplant centers (Black, n = 215 (45%); Hispanic, n = 401 (23%); and White, n = 2,267 (36%); P < .001). Being Black was strongly associated with mortality (Black, 32% vs non-Black, 15%; odds ratio, 3.0 [95% confidence interval, 1.6-5.8]; P = .001), as assessed using the risk-adjusted regression model. This racial disparity disappeared in a sensitivity analysis including only patients with a maximum Child-Pugh score of 13 (odds ratio 1.2 [95% confidence interval, 0.4-3.6]; P = .68), performed to compensate for the absence of Model for End-stage Liver Disease scores. Ethnoracial differences in access to teaching hospitals, liver transplant centers, first-line endoscopy, and transfusion did not significantly contribute (P > .05) to risk-adjusted mortality. CONCLUSIONS: Black patients have a 2-fold higher inpatient mortality than non-Black patients following TIPS creation for acute variceal bleeding, possibly related to greater disease severity before the procedure.

Are we putting ourselves in danger? Occupational hazards and job safety for orthopaedic surgeons.

As physicians, we strive to meet the needs of our patients. In doing so, we are often exposed to hazards that have the potential to not only compromise our health, but also our ability to deliver the best possible healthcare. Occupational hazards specific to the field of orthopaedics include infectious organisms, radiation, surgical smoke, chemicals, hazardous noise, musculoskeletal injury, and psychosocial stressors. Even though orthopaedic surgeons acknowledge the risk, most lack in-depth knowledge of the associated long-term harm associated with these hazards and ways of reducing risk of exposure. Orthopaedic surgeons should increase awareness, follow established guidelines, and integrate preventative measures to create the safest possible work environment. It is our hope that by improving our own health, we will be better equipped to address the health concerns of those we serve-our patients.

Neural crest-derived mesenchymal progenitor cells enhance cranial allograft integration.

Replacement of lost cranial bone (partly mesodermal and partly neural crest-derived) is challenging and includes the use of nonviable allografts. To revitalize allografts, bone marrow-derived mesenchymal stromal cells (mesoderm-derived BM-MSCs) have been used with limited success. We hypothesize that coating of allografts with induced neural crest cell-mesenchymal progenitor cells (iNCC-MPCs) improves implant-to-bone integration in mouse cranial defects. Human induced pluripotent stem cells were reprogramed from dermal fibroblasts, differentiated to iNCCs and then to iNCC-MPCs. BM-MSCs were used as reference. Cells were labeled with luciferase (Luc2) and characterized for MSC consensus markers expression, differentiation, and risk of cellular transformation. A calvarial defect was created in non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice and allografts were implanted, with or without cell coating. Bioluminescence imaging (BLI), microcomputed tomography (µCT), histology, immunofluorescence, and biomechanical tests were performed. Characterization of iNCC-MPC-Luc2 vs BM-MSC-Luc2 showed no difference in MSC markers expression and differentiation in vitro. In vivo, BLI indicated survival of both cell types for at least 8 weeks. At week 8, µCT analysis showed enhanced structural parameters in the iNCC-MPC-Luc2 group and increased bone volume in the BM-MSC-Luc2 group compared to controls. Histology demonstrated improved integration of iNCC-MPC-Luc2 allografts compared to BM-MSC-Luc2 group and controls. Human osteocalcin and collagen type 1 were detected at the allograft-host interphase in cell-seeded groups. The iNCC-MPC-Luc2 group also demonstrated improved biomechanical properties compared to BM-MSC-Luc2 implants and cell-free controls. Our results show an improved integration of iNCC-MPC-Luc2-coated allografts compared to BM-MSC-Luc2 and controls, suggesting the use of iNCC-MPCs as potential cell source for cranial bone repair.

Correlation and Agreement of Yttrium-90 Positron Emission Tomography/Computed Tomography with Ex Vivo Radioembolization Microsphere Deposition in the Rabbit VX2 Liver Tumor Model.

PURPOSE: To demonstrate a stronger correlation and agreement of yttrium-90 (90Y) positron emission tomography (PET)/computed tomography (CT) measurements with explant liver tumor dosing compared with the standard model (SM) for radioembolization. MATERIALS AND METHODS: Hepatic VX2 tumors were implanted into New Zealand white rabbits, with growth confirmed by 7 T magnetic resonance imaging. Seventeen VX2 rabbits provided 33 analyzed tumors. Treatment volumes were calculated from manually drawn volumes of interest (VOI) with three-dimensional surface renderings. Radioembolization was performed with glass 90Y microspheres. PET/CT imaging was completed with scatter and attenuation correction. Three-dimensional ellipsoid VOI were drawn to encompass tumors on fused images. Tumors and livers were then explanted for inductively coupled plasma (ICP)-optical emission spectroscopy (OES) analysis of microsphere content. 90Y PET/CT and SM measurements were compared with reference standard ICP-OES measurements of tumor dosing with Pearson correlation and Bland-Altman analyses for agreement testing with and without adjustment for tumor necrosis. RESULTS: The median infused activity was 33.3 MBq (range, 5.9-152.9). Tumor dose was significantly correlated with 90Y PET/CT measurements (r = 0.903, P < .001) and SM estimates (r = 0.607, P < .001). Bland-Altman analyses showed that the SM tended to underestimate the tumor dosing by a mean of -8.5 Gy (CI, -26.3-9.3), and the degree of underestimation increased to a mean of -18.3 Gy (CI, -38.5-1.9) after the adjustment for tumor necrosis. CONCLUSIONS: 90Y PET/CT estimates were strongly correlated and had better agreement with reference measurements of tumor dosing than SM estimates.

Two-level cervical disc arthroplasty in patients with Klippel-Feil syndrome: A case report and review of the literature.

BACKGROUND: Klippel-Feil syndrome (KFS) is defined by multiple abnormal segments of the cervical spine with congenital synostosis of two or more cervical vertebrae. KFS patients who demonstrate progressive symptomatic instability and/or neurologic sequelae are traditionally managed with operative decompression and arthrodesis. CASE DESCRIPTION: A 44-year-old female with chronic neck pain and radiculopathy and a C7-T1 KFS presented with adjacent segment degenerative disc disease at the C5-6 and C6-7 levels. She was successfully managed with a two-level cervical disc arthroplasty (CDA). CONCLUSION: Patients with KFS and disease at two contiguous, adjacent levels (e.g., cervical disc disease) may be safely and effectively managed with two-level CDA.

Cost Analysis of Dialysis Access Maintenance Interventions across Physician Specialties in U.S. Medicare Beneficiaries.

Background Dialysis maintenance interventions account for billions of dollars in U.S. Medicare spending and are performed by multiple medical specialties. Whether Medicare costs differ by physician specialty is, to the knowledge of the authors, not known. Purpose To assess patency-adjusted costs of endovascular dialysis access maintenance by physician specialty. Materials and Methods In this retrospective longitudinal cohort study, patients who were beneficiaries of Medicare undergoing their first arteriovenous access placement in 2009 were identified by using billing codes in the 5% Limited Data Set. By tracking their utilization data through 2014, postintervention primary patency and aggregate payments associated with maintenance interventions were calculated. Unadjusted payments per year of access patency gain were compared across physician specialty. A general linear mixed-effects model adjusted for covariates was used, as follows: patient characteristics, access type (fistula vs graft), clinical severity, type of intervention (angioplasty, stent, thrombolysis), clinical location (hospital outpatient vs office-based laboratory), and resource utilization (operating room use, anesthesia use). Results First arteriovenous access was performed in 1479 beneficiaries (mean age, 63 years ± 15 [standard deviation]; 820 men) in 2009. Through 2014, 8166 maintenance interventions were performed in this cohort. Unadjusted mean Medicare payments for each incremental year of patency were as follows: $71 000 for radiologists, $89 000 for nephrologists, and $174 000 for surgeons. Billing for operating room (41.8% [792 of 1895], surgery; 10.2% [277 of 2709], nephrology; and 31.1% [1108 of 3562], radiology) and anesthesia (19.9% [377 of 1895], surgery; 2.6% [70 of 2709], nephrology; 4.7% [170 of 3562], radiology) varied by specialty and accounted for 407% and 132% higher payments, respectively. After adjusting for clinical severity and location, type of intervention, and resource utilization, nephrologists and surgeons had 59% (95% confidence interval: 44%, 73%; P < .001) and 57% (95% confidence interval: 43%, 72%; P < .001) higher payments, respectively, for the same patency gain compared with radiologists. Operating room use and anesthesia services were major drivers of higher cost, with 407% (95% confidence interval: 374%, 443%; P < .001) and 132% (95% confidence interval: 116%, 150%; P < .001) higher costs, respectively. Conclusion Patency-adjusted payments for hemodialysis access maintenance differed by physician specialty, driven partly by discrepant rates of billing for operating room and anesthesia use. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by White in this issue.

Excimer Laser Sheath-Assisted Retrieval of "Closed-Cell" Design Inferior Vena Cava Filters.

Background Numerous reports have shown that inferior vena cava filters are associated with clinically significant adverse events. Complicating factors, such as caval incorporation, may lead to technical challenges at retrieval. The use of advanced techniques including the laser sheath have increased technical success rates; however, the data are limited on which filter types necessitate and benefit from its use. Methods and Results From October 2011 to September 2019, patients with inferior vena cava filter dwell times >6 months or with prior failed retrievals were considered for laser sheath-assisted retrieval. Standard and nonlaser advanced retrieval techniques were attempted first; if the filter could not be safely or successfully detached from the caval wall using these techniques, the laser sheath was used. Technical success, filter type, necessity for laser sheath application based on "open" versus "closed-cell" filter design, dwell times, and adverse events were evaluated. A total of 441 patients (216 men; mean age, 54 years) were encountered. Mean dwell times for all filters was 56.6 months, 54.4 among closed-cell filters and 58.5 among open-cell filters (P=0.63). Technical success of retrieval was 98%, with the laser sheath required in 143 cases (40%). Successful retrieval of closed-cell filters required laser sheath assistance in 60% of cases as compared with 7% of open-cell filters (odds ratio, 20.1; P<0.01). In closed-cell inferior vena cava filters, dwell time was significantly associated with need for laser, requiring it in 64% of retrievals with dwell times >6 months (P=0.01). One major adverse event occurred among laser sheath retrievals when a patient required a 2-day inpatient admission for a femoral access site hemorrhage. Conclusions Closed-cell filters may necessitate the use of the laser sheath for higher rates of successful and safe retrieval.

Inferior Vena Cava Filter Retrieval: Patient Selection, Procedural Planning, and Postprocedural Complications.

OBJECTIVE. Utilization of retrievable inferior vena cava filters (rIVCFs) has come under increased scrutiny because of historically high rates of placement, generalized lack of retrieval when the inferior vena cava filter (IVCF) is no longer indicated, and reports of device-related complications. These events have led to an increased interest in IVCF retrieval, including the development of advanced endovascular retrieval techniques and the proliferation of specialized clinical practices for rIVCFs. We aim to describe the indications for IVCF retrieval, patient selection, procedural planning, and procedural complications and management. CONCLUSION. IVCFs continue to have a role in the prevention of pulmonary embolism in select patients. Rising awareness of device-related complications paired with historically low retrieval rates has prompted renewed emphasis and interest in filter retrieval. Diligent follow-up and procedural planning permit prompt and safe filter retrieval.