Cone-Beam CT With Enhanced Needle Guidance and Augmented Fluoroscopy Overlay: Applications in Interventional Radiology.

Digital flat-panel detector cone-beam CT (CBCT), introduced in the early 2000s, was historically used in interventional radiology primarily for liver-directed therapies. However, contemporary advanced imaging applications, including enhanced needle guidance and augmented fluoroscopy overlay, have evolved substantially over the prior decade and now work synergistically with CBCT guidance to overcome limitations encountered with other imaging modalities. CBCT with advanced imaging applications has become increasingly used to facilitate a broad range of minimally invasive procedures, particularly relating to pain and musculoskeletal interventions. Potential advantages of CBCT with advanced imaging applications include greater accuracy for complex needle paths, improved targeting in the presence of metal artifact, enhanced visualization during injection of contrast medium or cement, increased ease when space in the gantry is limited, and reduced radiation doses versus conventional CT guidance. Nonetheless, CBCT guidance remains underutilized, partly relating to lack of familiarity with the technique. This article describes the practical implementation of CBCT with enhanced needle guidance and augmented fluoroscopy overlay and depicts the technique's application for an array of interventional radiology procedures, including epidural steroid injections, celiac plexus block and neurolysis, pudendal block, spine ablation, percutaneous osseous ablation fixation and osteoplasty, biliary recanalization, and transcaval type II endoleak repair.

Vertebral Body Bone Ablation with and without a Saline-Infused System in a Porcine Model.

The purpose of this study was to evaluate the effect of bone radiofrequency (RF) ablation in the spine with and without controlled saline infusion. RF ablation with and without controlled saline infusion was performed in the vertebral bodies of 2 swine with real-time temperature and impedance recordings. Histology and magnetic resonance (MR) imaging results were reviewed to evaluate the ablation zone size, breach of spinal canal, and damage to the spinal cord and nerves. There was no difference in maximum and mean temperatures between controlled saline and noninfusion groups. The impedance and power output were not significantly different between the groups. MR imaging and histopathology demonstrated ablation zones confined within the vertebral bodies. Ablation zone size correlated on MR imaging and histopathology by groups. No ablation effect, breach of posterior cortex, spinal cord injury, or nerve or ganglion injury was observed at any level using MR imaging or histology. Controlled saline infusion does not appear to impact bone RF ablation and, specifically, does not increase the ablation zone size.

Image guidance in osteoplasty and fixation.

Oncology patients, particularly those with breast, colorectal, prostate, renal and pancreatic cancers, are living longer due to advances in detection, and treatment. Unfortunately, this has come with a commensurate increase in the prevalence of osseous metastases and skeletal related events approaching 100,000 new patients each year. Patients are now experiencing serious morbidity and mortality due to pathologic fractures, altered structural mechanics, and cancer related bone pain. This patient population poses challenges for conventional open surgical and/or medical management often due to disease extent, location, and, in general, poor surgical candidacy. Percutaneous techniques may also be challenging under image guidance due to limited ability to use traditional orthopedic corridors, loss of cortical landmarks with destructive lesions, and need for live image guidance. Modern angiography suites with cone beam computed tomography (CBCT) and advanced imaging applications including needle guidance, 3D fusion, tumor segmentation, and angio-CT have facilitated the development of novel minimally invasive techniques for pain palliation and stabilization. The interventional radiologist is uniquely positioned to harness these advanced imaging applications and offer effective, safe, minimally invasive treatment options to patients with neoplastic disease within the axial, and appendicular skeletons. The focus of this article is to address the technical aspects of patient preparation, positioning, advanced imaging system capabilities, guidance strategies, and pitfalls during osteoplasty and fixation procedures.

Local Control of Cancers With Various Ablation Techniques.

Metastatic disease to the bone and soft tissue creates significant morbidity because of pain resulting in decreased functional status. Palliative chemotherapy and radiation therapy were historically the mainstays of pain reduction. Minimally invasive technologies such as image-guided ablation and cementoplasty have become common in interventional radiology. Advances in image guidance and ablation technologies have improved the multidisciplinary approach in the management of bone and soft-tissue disease. The minimally invasive nature of the interventions allows prompt initiation or continuation of chemotherapy and radiation therapy. These safe and efficacious procedures have improved patient quality of life by decreasing pain and improving function.

Vertebroplasty, Kyphoplasty, and Implant-Based Mechanical Vertebral Augmentation.

Vertebral compression fractures are a global public health issue with a quantifiable negative impact on patient morbidity and mortality. The contemporary approach to the treatment of osteoporotic fragility fractures has moved beyond first-line nonsurgical management. An improved understanding of biomechanical forces, consequential morbidity and mortality, and the drive to reduce opioid use has resulted in multidisciplinary treatment algorithms and significant advances in augmentation techniques. This review will inform musculoskeletal radiologists, interventionalists, and minimally invasive spine surgeons on the proper work-up of patients, imaging features differentiating benign and malignant pathologic fractures, high-risk fracture morphologies, and new mechanical augmentation device options, and it describes the appropriate selection of devices, complications, outcomes, and future trends.

Minimally Invasive Stabilization with or without Ablation for Metastatic Periacetabular Tumors.

BACKGROUND: Metastatic bone disease in the periacetabular region represents a potentially devastating problem for patients. Surgical treatment can offer pain relief and restore function. We describe a series of patients treated with minimally invasive osteoplasty and screw fixation with or without ablation. METHODS: Thirty-eight patients with 16 different metastatic tumor subtypes were managed with osteoplasty and screw fixation with or without ablation at a single institution. A retrospective review was performed to determine functional outcomes with use of the 1993 Musculoskeletal Tumor Society (MSTS) score as well as changes in narcotic usage. RESULTS: MSTS scores improved for all patients following surgery. Narcotic usage decreased in >80% of patients. Approximately half of the operations were outpatient procedures. Complications were minimal, there were no delays in chemotherapy or radiation due to surgical wound concerns, and there were no surgery-related deaths. The mean duration of follow-up was 9 months, with a 39% survival rate at the time of writing. Six of the 12 patients who survived for >1 year required additional procedures at a mean of 12 months (range, 4 to 23 months). CONCLUSIONS: Treatment of periacetabular metastatic disease with minimally invasive stabilization with or without ablation provides pain relief and functional improvement with lower complication rates than previously reported open reconstruction techniques. The minimally invasive approach allows for rapid initiation of chemotherapy and radiation. Patients with particularly aggressive cancers that are poorly responsive to systemic therapies and radiation may have progression of disease and may require additional procedures. Conversion to total hip arthroplasty was uncomplicated, and the cement and screw constructs were retained, providing a stable base for the arthroplasty reconstruction. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Minimally Invasive Stabilization of Periacetabular Metastasis.

Metastatic bone disease to the pelvis can lead to lower quality of life and function secondary to pain. Historically, treatment was palliative with radiation therapy and chemotherapy used to reduce pain. The Harrington procedure and subsequent modifications improved pain and function. In the subset of patients with complications, this would delay potential life-prolonging interventions such as chemotherapy and radiation therapy. Percutaneous palliative pain procedures including ablation and cementoplasty have been developed by interventional radiology for pelvic lesions and have been shown to be safe and efficacious. Additionally, percutaneous methods of pelvic fracture fixation have been developed. Modern image guidance technologies have allowed an expanded multidisciplinary approach to pelvic metastatic disease in a minimally invasive fashion with combinations of ablation, internal fixation, and cementation to improve patient quality of life and outcomes with decreased morbidity and rapid return to radiation and systemic therapies.

Pelvis weight-bearing ability after minimally invasive stabilizations for periacetabular lesion.

Periacetabular metastatic lesions cause debilitating weight-bearing pain and pose a risk of pelvic pathologic fracture. Minimally invasive percutaneous stabilization is an alternative palliative therapy over extensive open reconstructive surgeries. This study aimed to investigate the biomechanical behaviors of three distinct techniques of percutaneous periacetabular stabilization. A total of 20 composite hemipelves custom-made to contain Harrington type III periacetabular lesion based on a patient's computed tomograpy scans were assigned to treatment groups of cementoplasty alone using polymethyl methacrylate (Cement), screw fixation alone using ischial and posterior-to-anterior screws (Screws), cement-augmented screws (Screws&Cement), and a control group (Untreated). All hemipelves were loaded in a mechanical test configuration mimicking a single-legged stance, and failure load, failure deformation, and construct stiffness were determined. In the experiments, Screws&Cement demonstrated the highest yield strength (4711 ± 362 N) and was 12% higher than Cement (4005 ± 304 N, p = 0.019), 125% higher than Screws (2097 ± 359 N, p < 0.0001), and 184% higher than Untreated (1658 ± 254 N, p < 0.0001). No significant difference in yield strength was found between Screws and Untreated. Screws&Cement also demonstrated the highest stiffness (1013 ± 92 N/mm), followed by Cement (893 ± 49 N/mm), and both groups were significantly stiffer than Screws (543 ± 114 N/mm, p < 0.0001) and Untreated (580 ± 91 N/mm, p < 0.0001 for Screws&Cement, and p = 0.0003 for Cement). This study demonstrated that a cement-augmented periacetabular reconstruction is an effective option for percutaneous treatment of Harrington III periacetabular metastatic lesion. The addition of pelvic screws over cementoplasty significantly improved the pelvis load-bearing strength. When large periacetabular lesions are present, augmented screw fixation appears to be the superior choice of treatment.

Advanced Interventional Pain Management Approach to Neoplastic Disease Outside the Spine.

Neoplastic disease of the musculoskeletal system may result in serious morbidity and mortality secondary to cancer related bone pain, pathologic fracture, altered structural mechanics, and involvement of adjacent structures.1 Recent advances in cancer detection and treatment have allowed more patients to live longer. The prevalence of osseous metastatic disease has increased to 100,000 new patients developing bone metastases each year.2 These patients are seeing long-term exposure to chemotherapy and radiation leading to increased skeletal events, morbidity, and a negative impact on quality of life. Bone metastases in conjunction with poor bone quality often prevent surgical therapy. Utilization of thermal ablation in this patient population is supported by contemporary literature and offers a minimally invasive approach to pain palliation, local tumor control, and decreased morbidity with unique advantages compared to surgery or radiation.3 In addition to spine disease, interventional radiologists are able to meaningfully impact pelvic, shoulder girdle, and long bone metastases. Adding to ablation we have in our repertoire the ability to provide structural support utilizing cement and/or screw fixation as an adjunct for both pain palliation and mechanical stabilization.4-6 These novel therapies have allowed more patients with metastatic disease to be treated. The focus of this chapter is to highlight importance of patient selection, ablative modality selection, integration of cementoplasty (also described as osteoplasty) and osseous fixation, and procedural techniques/strategy in the pelvis and other common sites of bone metastases outside the spine.

Minimally Invasive Stabilization Using Screws and Cement for Pelvic Metastases: Technical Considerations for the Pelvic "Screw and Glue" Technique.

Metastatic disease involving the pelvis is common, often resulting in significant pain and disability. Several percutaneous interventions for unstable pelvic metastatic disease have been described, including osteoplasty, ablation, and screw fixation, that when used alone or in combination can significantly reduce pain and disability from metastatic bone disease. While it is possible to make a significant impact in patient care with basic principles and techniques, certain advanced techniques can extend the application of percutaneous interventions while minimizing morbidity.

Percutaneous cryoablation for the treatment of extra-abdominal desmoid tumors.

BACKGROUND: Desmoid tumors are rare locally invasive, benign neoplasms that develop along aponeurotic structures. Current treatment is complicated by associated morbidity and high recurrence rates. METHODS: A retrospective, single-institution review identified 23 patients (age: 16-77) with extra-abdominal desmoid tumors who received CT-guided percutaneous cryoablation as either a first-line (61%) or salvage (39%) treatment in 30 sessions between 2014 and 2018. Median maximal lesion diameter was 69 mm (range: 11-209). Intent was curative in 52% and palliative in 48%. Contrast-enhanced cross-sectional imaging was obtained before and after treatment in addition to routine clinical follow-up. RESULTS: Technical success was achieved in all patients. The median follow-up was 15.4 months (3.5-43.4). Symptomatic improvement was demonstrated in 89% of patients. At 12 months, the average change in viable volume was -80% (range -100% to + 10%) and response by modified response evaluation criteria in solid tumors (mRECIST) was CR 36%, PR 36%, and SD 28% No rapid postablation growth or track seeding was observed. Four patients underwent repeat cryoablation for either residual or recurrent disease. Two patients sustained a major procedural complication consisting of significant neuropraxia. CONCLUSION: Cryoablation for desmoid tumors demonstrates a high degree of symptom improvement and local tumor control on early follow-up imaging with relatively low morbidity.

Magnetic Resonance-Guided Focused Ultrasound: A Brief Review With Emphasis on the Treatment of Extra-abdominal Desmoid Tumors.

Magnetic resonance-guided focused ultrasound (MRgFUS) utilizes high-intensity focused ultrasound to noninvasively, thermally ablate lesions within the body while sparing the intervening tissues. Magnetic resonance imaging provides treatment planning and guidance, and real-time magnetic resonance thermometry provides continuous monitoring during therapy. Magnetic resonance-guided focused ultrasound is ideally suited for the treatment of extra-abdominal desmoid fibromatosis due to its noninvasiveness, lack of ionizing radiation, low morbidity, and good safety profile. Conventional treatments for these benign tumors, including surgery, radiation, and chemotherapy, can carry significant morbidity. Magnetic resonance-guided focused ultrasound provides a safe and effective alternative treatment in this often-young and otherwise healthy patient population. While there is considerable experience with MRgFUS for treatment of uterine fibroids, painful bone lesions, and essential tremor, there are few reports in the literature of its use for treatment of benign or malignant soft tissue tumors. This article reviews the principles and biologic effects of high-intensity focused ultrasound, provides an overview of the MRgFUS treatment system and use of magnetic resonance thermometry, discusses the use of MRgFUS for the treatment of extra-abdominal desmoid tumors, and provides several case examples.

Management of vertebral fragility fractures: a clinical care pathway developed by a multispecialty panel using the RAND/UCLA Appropriateness Method.

BACKGROUND CONTEXT: Vertebral fragility fractures (VFFs), mostly due to osteoporosis, are very common and are associated with significant morbidity and mortality. There is a lack of consensus on the appropriate management of patients with or suspected of having a VFF. PURPOSE: This work aimed at developing a comprehensive clinical care pathway (CCP) for VFF. STUDY DESIGN/SETTING: The RAND/UCLA Appropriateness Method was used to develop patient-specific recommendations for the various components of the CCP. The study included two individual rating rounds and two plenary discussion sessions. METHODS: A multispecialty expert panel (orthopedic and neurosurgeons, interventional [neuro]radiologists and pain specialists) assessed the importance of 20 signs and symptoms for the suspicion of VFF, the relevance of 5 diagnostic procedures, the appropriateness of vertebral augmentation versus nonsurgical management for 576 clinical scenarios, and the adequacy of 6 aspects of follow-up care. RESULTS: The panel identified 10 signs and symptoms believed to be relatively specific for VFF. In patients suspected of VFF, advanced imaging was considered highly desirable, with MRI being the preferred diagnostic modality. Vertebral augmentation was considered appropriate in patients with positive findings on advanced imaging and in whom symptoms had worsened and in patients with 2 to 4 unfavorable conditions (eg, progression of height loss and severe impact on functioning), dependent on their relative weight. Time since fracture was considered less relevant for treatment choice. Follow-up should include evaluation of bone mineral density and treatment of osteoporosis. CONCLUSIONS: Using the RAND/UCLA Appropriateness Method, a multispecialty expert panel established a comprehensive CCP for the management of VFF. The CCP may be helpful to support decision-making in daily clinical practice and to improve quality of care.

Analysis of Reporting Bias in Vertebral Augmentation.

Osteoporotic vertebral compression fractures (OVCFs) are a significant cause of morbidity and mortality in the United States and worldwide, with estimates of 750,000 to 1.5 million occurring annually. As the elderly population continues to increase, the incidence of OVCFs will continue to rise, as will the morbidity and mortality associated with this condition. Vertebral augmentation (VA) was almost universally accepted as the appropriate treatment modality prior to 2 sham trials published in 2009 by the New England Journal of Medicine (NEJM). Subsequently, there is now significant controversy regarding the optimal treatment of OVCFs. Since 2009 there have been 6 prospective randomized controlled studies (PRCTs) and 2 meta-analyses on VA for the treatment of OVCFs. Five of the PRCTs and both of the meta-analyses have shown superior results with VA as compared with nonsurgical management (NSM). However, a recent health technology assessment and review article continue to over-emphasize the 2 NEJM sham trials, despite the most current literature. These are examples of inconsistent or biased data reporting with overemphasis on certain trial types and exclusion of other types of data, resulting in the reporting of conclusions that are partially representative or not representative of the complete data. As clinical investigators, we have a responsibility to limit bias and ensure that the appropriate treatment modalities are made available to vulnerable populations.The aim of this perspective analysis is to examine sources of bias in reporting and some of the publications that contain it, along with comparing the publications to the current body of published literature relevant to this topic. KEY WORDS: Vertebral augmentation, vertebroplasty, kyphoplasty, bias, osteoporosis, compression fracture.

Safety and Efficacy of Minimally Invasive Acetabular Stabilization for Periacetabular Metastatic Disease with Thermal Ablation and Augmented Screw Fixation.

PURPOSE: To evaluate minimally invasive acetabular stabilization (MIAS) with thermal ablation and augmented screw fixation for impending or minimally displaced fractures of the acetabulum secondary to metastatic disease. MATERIALS AND METHODS: Between February 2011 and July 2014, 13 consecutive patients underwent thermal ablation, percutaneous screw fixation, and polymethyl methacrylate augmentation for impending or nondisplaced fractures of the acetabulum secondary to metastatic disease. Functional outcomes were evaluated before and after the procedure using the Musculoskeletal Tumor Society (MSTS) scoring system. Complications, hospital length of stay, and eligibility for chemotherapy and radiation therapy were assessed. RESULTS: All procedures were technically successful with no major periprocedural complications. The mean total MSTS score improved from 23% ± 11 before MIAS to 51% ± 21 after MIAS (P < .05). The mean MSTS pain scores improved from 0% (all) to 32% ± 22 after MIAS (P < .05). The mean MSTS walking ability score improved from 22% ± 19 to 55% ± 26 after MIAS (P < .05). Two complications occurred; a patient had a minimally displaced fracture of the superior pubic ramus at the site of repair but remained ambulatory, and septic arthritis was diagnosed in another patient 12 months after repair. The average length of hospital stay was 2 days ± 3.6; six patients were discharged within 24 hours of the procedure. All patients were eligible for chemotherapy and radiation therapy immediately after the procedure. CONCLUSIONS: MIAS is feasible, improves pain and mobility, and offers a minimally invasive alternative to open surgical reconstruction.

Evaluation of catheter infection rates in converted dialysis catheters versus de novo placement in the setting of chlorhexidine use.

PURPOSE: Prior studies have reported infection rates of converting non-tunneled dialysis catheters (NTDCs) to tunneled dialysis catheters (TDCs) versus de novo placement of TDCs using povidone-iodine. Chlorhexidine, per the Center of Disease Control guidelines, has been exclusively used in our institution since 2005. Therefore, our study aims to determine whether there is a difference in infection rates between conversion and de novo placement when utilizing chlorhexidine. MATERIALS AND METHODS: A retrospective analysis from 1/1/2009 to 8/10/2012 was performed of patients who underwent placement of NTDCs, which were subsequently converted to TDCs and those who underwent de novo TDC placement. To assess the rate of infection, the following data points were collected: date of procedure(s), indication, outcomes, site of catheter insertion, pre- and post-procedure laboratory values, complications, infection rates within the life of the initially placed catheter, catheter days, and survival. RESULTS: The conversion cohort was composed of 205 patients, 135 of whom were lost to follow-up, leaving 70 patients. The de novo cohort included 70 randomly selected patients. Of the 70 patients who underwent conversion, 23 developed a catheter-related infection, with an infection rate of 0.26 events per 100 catheter days. Of the 70 de novo catheters, 20 developed infection with an infection rate of 0.25 events per 100 catheters days. CONCLUSION: In this series, there is no difference in infection rates between conversion and de novo TDC placement when utilizing chlorhexidine as the sterilization agent. However, these infection rates are superior to those reported when using povidone-iodine.

A Cross-Sectional Survey of Interventional Radiologists and Vascular Surgeons Regarding the Cost and Reimbursement of Common Devices and Procedures.

PURPOSE: To evaluate knowledge of interventional radiologists (IRs) and vascular surgeons (VSs) on the cost of common devices and procedures and to determine factors associated with differences in understanding. MATERIALS AND METHODS: An online survey was administered to US faculty IRs and VSs. Demographic information and physicians' opinions on hospital costs were elicited. Respondents were asked to estimate the average price of 15 commonly used devices and to estimate the work relative value units (wRVUs) and average Medicare reimbursements for 10 procedures. Answer estimates were deemed correct if values were ± 25% of the actual costs. Multivariate logistical regression was used to calculate odds ratios and 95% confidence intervals. RESULTS: Of the 4,926 participants contacted, 1,090 (22.1%) completed the questionnaire. Overall, 19.8%, 22.8%, and 31.9% were accurate in price estimations of devices, Medicare reimbursement, and wRVUs for procedures. Physicians who thought themselves adequately educated about wRVUs were more accurate in predicting procedural costs in wRVUs than physicians who responded otherwise (odds ratio = 1.40, 95% confidence interval, 1.29-1.52; P < .0001). Estimation accuracies for procedures showed a positive trend in more experienced physicians (≥ 16 y), private practice physicians, and physicians who practice in rural areas. CONCLUSIONS: This study suggests that IRs and VSs have limited knowledge regarding device costs. Given the current health care environment, more attention should be placed on cost education and awareness so that physicians can provide the most cost-effective care.

Safety and efficacy of transarterial chemoembolization in patients with transjugular intrahepatic portosystemic shunts.

BACKGROUND: Transarterial chemoembolization (TACE) for the treatment of hepatocellular carcinoma (HCC) is an important option as the majority of patients present with advanced disease. Data regarding treatment outcomes in patients who have undergone transjugular intrahepatic portosystemic shunts (TIPS) are limited. The present study seeks to evaluate the safety and efficacy of TACE in HCC patients with a TIPS. METHODS: A retrospective review identifying patients with HCC and concomitant TIPS who were treated with TACE was performed. RESULTS: From 1999 to 2014, 16 patients with HCC underwent a total of 27 TACE procedures; eight patients required multiple treatments. The median patient age at the time of the initial TACE was 60.5 years [interquartile range (IQR) : 52.5-67.5] with the majority being male (n = 12, 75%) and Childs-Pugh Class B (n = 12, 75%). At 6 weeks after TACE, 56.3% of patients achieved an objective response rate (complete and partial response) by mRECIST criteria. Clavien Grade 3 or higher complications occurred in 11.1% of TACE procedures. There were no peri-procedural deaths. The median progression-free (PFS) and overall survival (OS) were 9 and 22 months, respectively, when censored for liver transplantation (median follow-up: 11.5 months). CONCLUSION: TACE is an effective treatment strategy for HCC in TIPS patients; albeit may be associated with higher complication rates.

Complications in musculoskeletal intervention: important considerations.

Musculoskeletal (MSK) intervention has proliferated in recent years among various subspecialties in medicine. Despite advancements in image guidance and percutaneous technique, the risk of complication has not been fully eliminated. Overall, complications in MSK interventions are rare, with bleeding and infection the most common encountered. Other complications are even rarer. This article reviews various complications unique to musculoskeletal interventions, assists the reader in understanding where pitfalls lie, and highlights ways to avoid them.