Safety and Effectiveness of Stellate Ganglion Cryoablation in Complex Regional Pain Syndrome.

This was a retrospective, observational, descriptive study to evaluate the safety and 6-month effectiveness of percutaneous cryoablation of the stellate ganglion for the treatment of complex regional pain syndrome (CRPS). Eight patients with CRPS diagnosed by Budapest criteria were treated with this procedure. CRPS symptom severity was assessed prior to the procedure and at 3-month intervals after the procedure using a novel CRPS scoring system-the Budapest score-created by the authors. The mean Budapest score prior to and 6 months (187 days, SD ± 43) after stellate ganglion cryoablation was 7.0 (SD ± 2.0) (n = 6) and 3.8 (SD ± 2.3) (n = 6), respectively, showing a decrease of 3.2 (SD ± 1.7) (n = 6; P = .006). There were no major adverse events due to the procedure, and there was only 1 minor adverse event. Stellate ganglion cryoablation is a feasible, safe, and minimally invasive procedure that may represent an efficacious adjunct treatment option for select patients with CRPS.

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

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

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

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

Percutaneous CT-Guided Cryoneurolysis of the Intercostobrachial Nerve for Management of Postmastectomy Pain Syndrome.

PURPOSE: To evaluate the feasibility, safety, and efficacy of intercostobrachial nerve (ICBN) cryoneurolysis for pain control in patients with postmastectomy pain syndrome (PMPS). MATERIALS AND METHODS: Fourteen patients with PMPS were prospectively enrolled into this clinical trial after a positive response to a diagnostic computed tomography (CT)-guided percutaneous block of the ICBN. Participants subsequently underwent CT-guided percutaneous cryoneurolysis of the same nerve and were observed on postprocedural Days 10, 90, and 180. Pain scores, quality-of-life measurements, and global impression of change values were recorded before the procedure and at each follow-up point using established validated outcome instruments. RESULTS: Cryoneurolysis of the ICBN was technically successful in all 14 patients. The mean pain decreased significantly by 2.1 points at 10 days (P = .0451), by 2.4 points at 90 days (P = .0084), and by 2.9 points at 180 days (P = .0028) after cryoneurolysis. Pain interference with daily activities decreased significantly by 14.4 points after 10 days (P = .0161), by 16.2 points after 90 days (P = .0071), and by 20.7 points after 180 days (P = .0007). There were no procedure-related adverse events. CONCLUSIONS: Cryoneurolysis of the ICBN in patients with PMPS was technically feasible and safe and resulted in a significant decrease in postmastectomy pain for up to 6 months in this small cohort.

Percutaneous Image-guided Cryoneurolysis: Applications and Techniques.

The expansion and dissemination of interventional cryoneurolysis in recent years has been fueled by the integration of advanced imaging guidance, the evolution of our understanding of neuropathologic processes after exposure of nerves to cold, and opportunities for its use beyond pain management. The clinical translation of cryoneurolysis through interventional radiology requires consideration of many factors, including (a) the supply and composition of target nerves, (b) the value of diagnostic injection with imaging guidance for confirmation, (c) the integration of advanced imaging guidance that allows safe ablation, (d) the difference between neoplastic and nonneoplastic causes of pain, (e) the phenomenon of percutaneously induced neuroregeneration, (f) the potential to manage conditions other than pain, (g) the consideration of protocols, (h) the limitations of current technology, and (i) the potential complications and adverse effects. Cryoneurolysis has societal and legislative endorsement as an effective nonopioid option for pain palliation. The Centers for Medicare and Medicaid Services (CMS) approved three new category III Current Procedural Terminology (CPT) codes specifically for the cryoablation of nerves with advanced imaging guidance. Interventional radiologists who are aware of nerve-directed strategies see eligible patients in their daily practice and have opportunities to bundle procedures (eg, celiac plexus block at the time of a biliary drain for pancreatic cancer with low bile duct obstruction), offering an avenue to serve the patient, reduce opioid dependence, allow faster discharge, and establish name recognition of interventional radiologists. Also, the ability to use CT to target deep structures accurately and swiftly, often with only local anesthesia, compared with the usual monitored anesthesia care in a surgical setting, may provide another avenue to build a cryoneurolysis practice. ©RSNA, 2022.

Interventional Radiology Obesity Therapeutics: Proceedings from the Society of Interventional Radiology Foundation Research Consensus Panel.

The Society of Interventional Radiology Foundation commissioned a Research Consensus Panel to establish a research agenda on "Obesity Therapeutics" in interventional radiology (IR). The meeting convened a multidisciplinary group of physicians and scientists with expertise in obesity therapeutics. The meeting was intended to review current evidence on obesity therapies, familiarize attendees with the regulatory evaluation process, and identify research deficiencies in IR bariatric interventions, with the goal of prioritizing future high-quality research that would move the field forward. The panelists agreed that a weight loss of >8%-10% from baseline at 6-12 months is a desirable therapeutic endpoint for future IR weight loss therapies. The final consensus on the highest priority research was to design a blinded randomized controlled trial of IR weight loss interventions versus sham control arms, with patients receiving behavioral therapy.

Review of Extraosseous Applications of Thermal Ablation in the Treatment of Moderate to Severe Large Joint Osteoarthritis.

Osteoarthritis (OA) is the most common joint disease worldwide, leading to significant pain, restricted range of motion, and disability. A gap exists between short- and long-term symptom-relieving therapies. Although arthroplasty is an effective treatment for symptomatic end-stage disease, most patients ultimately do not receive a joint replacement due to suboptimal surgical qualifications, comorbidities, or an aversion to surgery. The lack of additional treatment options in this setting makes opioid agonists a commonly used pharmacologic agent, contributing to the addiction epidemic that greatly afflicts our communities. Cooled radiofrequency ablation (CRFA) has arisen as a treatment modality in the setting of moderate to severe OA among patients refractory to conservative management, generally showing greater efficacy compared with other existing strategies. This review focuses on the benefits of CRFA and its technical feasibility as a management option among patients experiencing debilitating large joint OA with limited clinical options.

Percutaneous CT-Guided Cryoablation of the Celiac Plexus: A Retrospective Cohort Comparison with Ethanol.

PURPOSE: To retrospectively analyze and compare the incidence of diarrhea in patients who underwent cryoablation of the celiac plexus for intractable abdominal pain versus ethanol therapy over a 5-year period. MATERIALS AND METHODS: From June 2014 to August 2019, 83 patients were identified who underwent neurolysis of the celiac plexus for management of intractable abdominal pain by using either cryoablation (n = 39 [59% female; age range, 36-79 years old [average, 60 ± 11 years old]) or alcohol (n = 44 [48% female; age range, 29-76 years old [average, 60 ± 12 years old]). Pain scores and reports of procedure-related complications or side effects, with special attention to diarrhea and/or other gastrointestinal symptoms, were collected from follow-up visits at 1 week, 1 month, and 3 months post-intervention and were compared between groups. RESULTS: The mean time of follow-up was 17.7 days. Four patients who underwent cryoablation developed gastrointestinal symptoms consisting of 2 cases of nausea and vomiting and 2 cases of diarrhea (5.1%). Twelve patients who underwent ethanol ablation developed gastrointestinal symptoms, including 1 case of nausea, 3 cases of vomiting, and 9 cases of diarrhea (20.5%). There was a significantly higher incidence of both diarrhea (chi-squared likelihood ratio, P = .03) and overall gastrointestinal symptoms (chi-squared likelihood ratio, P = .04) in the ethanol group than in the cryoablation group. CONCLUSIONS: Cryoablation of the celiac plexus may provide a new treatment option for intractable abdominal pain, and it appears to have a lower incidence of diarrhea and fewer gastrointestinal side effects than ablation using ethanol.

Natural History of Mixed and Motor Nerve Cryoablation in Humans-A Cohort Analysis.

Eight patients who underwent percutaneous cryoablation of mixed and/or motor nerves over a period of 5 years were identified. Distances from the ablation sites to origins of distal musculature were measured, and times to initial clinical recovery were collected. Strength progression over time following muscle activation was also collected and analyzed. All patients demonstrated activation of all muscles distal to the ablation, and the calculated mean rate of nerve regeneration based on distance to the origin of the assessed musculature and time to muscle activation for the group was 1.5 mm/day ± 1.1.

Image-Guided Transarterial Directed Delivery of Human Mesenchymal Stem Cells for Targeted Gastrointestinal Therapies in a Swine Model.

PURPOSE: To evaluate the feasibility of catheter-directed intra-arterial stem cell delivery of human mesenchymal stem cells (MSCs) to the small bowel in a porcine model. MATERIALS AND METHODS: The cranial mesenteric artery of 6 Yucatan minipigs was selectively catheterized under fluoroscopic guidance following cut-down and carotid artery access. A proximal jejunal branch artery was selectively catheterized for directed delivery of embolic microspheres (100-300 µm) or MSCs (0.1-10 million cells). The pigs were euthanized after 4 hours and specimens collected from the proximal duodenum and the targeted segment of the jejunum. The Chiu/Park system for scoring intestinal ischemia was used to compare hematoxylin and eosin-stained sections of jejunum and duodenum. RESULTS: Successful delivery of microspheres or MSCs in a proximal jejunal branch artery of the cranial mesenteric artery was achieved in all subjects. Radiopaque microspheres and post-delivery angiographic evidence of stasis in the targeted vessels were observed on fluoroscopy after delivery of embolics. Preserved blood flow was observed after MSC delivery in the targeted vessel. The Chiu/Park score for intestinal ischemia in the targeted proximal jejunal segments were similar for microspheres (4, 4; n = 2) and MSCs (4, 4, 4, 3; n = 4), indicating moderate ischemic effects that were greater than for control duodenal tissue (3, 1; 0, 0, 3, 3). CONCLUSIONS: Selective arteriographic deployment of MSCs in swine is feasible for study of directed intestinal stem cell delivery. In this study, directed therapy resulted in intestinal ischemia.

Generalist versus Subspecialist Workforce Characteristics of Invasive Procedures Performed by Radiologists.

Purpose To explore subspecialty workforce considerations surrounding invasive procedures performed by radiologists. Materials and Methods The 2015 Centers for Medicare & Medicaid Services Physician and Other Supplier Public Use File was used to identify all invasive procedures (Current Procedural Terminology code range, 10000-69999) billed by radiologists for Medicare fee-for-service beneficiaries. Radiologists were categorized by subspecialty according to the majority of their billable work-relative value units (wRVUs). Those without a single subspecialty majority work effort were deemed generalists. Procedures were categorized into three tiers of complexity (high, ≥4.0 wRVUs; mid, 1.6-3.9 wRVUs; low, ≤1.5 wRVUs). Total and tiered generalist versus subspecialist workforce composition was assessed. Results Just 25 unique services comprised more than 75% of invasive procedures performed by radiologists. Of radiologists who performed procedures, 57.5% were generalists, 15.8% were interventionalists, and 26.8% were other subspecialists. Of the radiologists who performed low-, mid-, and high-complexity procedures, generalists accounted for 46.3%, 30.9%, and 23.1%, respectively; interventionalists accounted for 35.4%, 30.9%, and 75.2%, respectively; and other subspecialists accounted for 18.3%, 14.6%, and 1.7%, respectively. Generalists were the dominant providers of six of the top 10 low-complexity and seven of the top 10 midcomplexity procedures. Interventionalists were the dominant providers of all top 10 high-complexity procedures. Nationally, over twice as many U.S. counties had local access to generalists (869 counties) for invasive procedures versus interventionalists (347 counties) or other subspecialists (380 counties). Conclusion Among radiologists, generalists perform far more procedures in more geographic locations and are more likely to serve patients with less complex service needs than are interventionalists or other subspecialists. Practices and professional societies must remain vigilant to ensure that the subspecialty evolution in radiology does not exacerbate patient access disparities. © RSNA, 2018 Online supplemental material is available for this article.

Structured Protocol for Benign Biliary Anastomotic Strictures: Impact on Long-Term Clinical Effectiveness.

OBJECTIVE: The purpose of this study is to compare long-term clinical effectiveness before and after implementation of a structured protocol for percutaneous drainage of benign anastomotic biliary strictures. MATERIALS AND METHODS: Three hundred five adult patients undergoing percutaneous biliary drainage for biliary anastomotic strictures between 1994 and 2015 were identified using Current Procedural Terminology billing codes, with 234 undergoing intervention before implementation of a structured protocol and 71 undergoing intervention after implementation of the protocol. The frequency of surgical anastomotic revision was compared between patients treated before and after the implementation of the structured protocol. Patient characteristics and treatment variables were also analyzed with respect to the frequency of surgical revision. A Kaplan-Meier analysis was performed to determine the long-term probabilities of avoiding surgical revision and patency rates. RESULTS: Overall, 72.8% of patients avoided surgical revision, with 71.1% before and 81.7% after the protocol was implemented (p = 0.1052). A larger maximum drain size was significantly associated with a lower frequency of surgical revision (p = 0.0006). The rates of surgical avoidance 5 years after treatment before and after protocol implementation were 69.1% and 80.8%, respectively. Patency rates 5 years after treatment before and after protocol implementation were 73.8% and 76.8%, respectively. CONCLUSION: Percutaneous drainage and management of benign biliary anastomotic strictures is an effective treatment regardless of the presence of a structured protocol. Although there was no significant benefit in terms of avoidance of surgical revision, the time until surgical revision and patency rates were increased with the protocol. In addition, a larger maximum drain size was associated with a better outcome.

Percutaneous Image-Guided Cryoneurolysis.

OBJECTIVE: The aim of this article is to review the available evidence regarding image-guided percutaneous cryoneurolysis, with a focus on indications, technique, efficacy, and potential complications. CONCLUSION: Percutaneous image-guided cryoneurolysis is safe and effective for the management of several well-described syndromes involving neuropathic pain. Additional rigorous prospective study is warranted to further define the efficacy and specific role of these interventions.

Percutaneous Image-Guided Cryoablation for the Treatment of Phantom Limb Pain in Amputees: A Pilot Study.

PURPOSE: To prospectively evaluate percutaneous image-guided nerve cryoablation for treatment of refractory phantom limb pain (PLP) in a pilot cohort for purposes of deriving parameters to design a larger, randomized, parallel-armed, controlled trial. MATERIALS AND METHODS: From January 2015 to January 2016, 21 patients with refractory PLP underwent image-guided percutaneous cryoneurolysis procedures. Visual analog scale scores were documented at baseline and 7, 45, and 180 days after the procedure. Responses to a modified Roland Morris Disability Questionnaire were documented at baseline and 7 and 45 days after the procedure. RESULTS: Technical success rate of the procedures was 100%. There were 6 (29%) minor procedure-related complications. Disability scores decreased from a baseline mean of 11.3 to 3.3 at 45-day follow-up (95% confidence interval 5.8, 10.3; P < .0001). Pain intensity scores decreased from a baseline mean of 6.2 to 2.0 at long-term follow-up (95% confidence interval 2.8, 5.6; P < .0001). CONCLUSIONS: Image-guided percutaneous nerve cryoablation is feasible and safe and may represent a new efficacious therapeutic option for patients with phantom pains related to limb loss.

Cryoablation of Osteoid Osteoma in the Pediatric and Adolescent Population.

PURPOSE: To evaluate the technical feasibility and clinical efficacy of osteoid osteoma (OO) cryoablation in a large, pediatric/adolescent cohort. MATERIALS AND METHODS: An electronic medical record and imaging archive review was performed to identify all cryoablations performed for OOs between 2011 and 2015 at a single tertiary care pediatric hospital. The subsequent analysis included 29 patients with suspected OOs treated by cryoablation (age range, 3-18 y; mean age, 11.3 y; 17 boys; 12 girls). Conventional CT guidance was used in 22 procedures; cone-beam CT guidance was used in 7 procedures. Follow-up data were obtained via a standardized telephone questionnaire (23/29 patients; 79.3%) and clinical notes (5/29 patients; 17.2%). One patient was lost to follow-up. RESULTS: Technical success was achieved in 100% of patients (29/29). Immediate clinical success (cessation of pain and nonsteroidal antiinflammatory drug [NSAID] use within 1 mo after the procedure) was achieved in 27/28 patients (96.4%). Short-term clinical success (cessation of pain and NSAID use for > 3 mo after the procedure) was achieved in 24/25 patients (96%). Long-term clinical success (cessation of pain and NSAID use for > 12 mo after the procedure) was achieved in 19/21 patients (90.5%). Median pain scale score before the procedure was 10 (range, 5-10); median pain scale score after the procedure was 0 (range, 0-8; P < .0001). There were 6 minor complications (21%) and no major complications. CONCLUSION: Image-guided cryoablation is a technically feasible, clinically efficacious therapeutic option for children and adolescents with symptomatic OO.

Inactivation of Bacteria on Explanted Dialysis Catheter Lumens with Fiber Optically Delivered Ultraviolet Light.

PURPOSE: To evaluate the germicidal effect of fiber optically delivered ultraviolet (UV) light on colonized explanted dialysis catheters. MATERIALS AND METHODS: Explanted dialysis catheters were screened for intraluminal colonization by culturing 1 mL of a saline flush. Catheters growing >10 colony-forming units were treated with doses of fiber optically delivered UV light (range, 40-1,300 mJ/cm2). For each UV-treated catheter, an unexposed segment was first cut and set aside as a control sample. A sterile optical fiber was inserted into the catheter hub and advanced to the catheter tip. The fiber was slowly withdrawn at a constant rate while exposing the inner lumen to UV light. A second UV-exposed segment was then removed. The UV-exposed and control segments were split and sonicated to remove the adherent bacteria. The bacteria were counted and identified. RESULTS: There were 14 colonized catheters treated with UV light. The catheters were primarily colonized with coagulase-negative staphylococci (60%) and Staphylococcus aureus (33%). There was a significant reduction in viable bacteria between the UV-treated versus untreated segments of each infected catheter (P = .04). In the seven treated catheters with >100,000 colony-forming units per cm2 of luminal surface area, there was a >99.5% reduction of viable bacteria in all UV-exposed samples, with no residual viable bacteria in four of seven (57%) of the samples. CONCLUSIONS: This study demonstrates the technical feasibility and benchtop efficacy of using fiber optics to deliver UV light into the lumen of a colonized dialysis catheter and inactivating bacteria on the intraluminal surface.

Percutaneous CT-guided cryoablation for the treatment of refractory pudendal neuralgia.

PURPOSE: To evaluate the safety and efficacy of percutaneous CT-guided cryoablation of the pudendal nerve for the treatment of refractory pudendal neuralgia. MATERIALS AND METHODS: Eleven patients were selected to undergo percutaneous CT-guided cryoablation of the pudendal nerve based on established diagnostic criteria. Brief Pain Inventory questionnaires were administered prior to the procedure, during the immediate 24 h post procedure, and 45 days and 6 months following the procedure. RESULTS: Prior to treatment, the average level of pain on a scale from 0 (no pain) to 10 (worst pain imaginable) was 7.6, with pain described as "burning" (80%), "pulling" (37.5%), "crushing" (50%), "pressure" (84.5%), "throbbing" (50%), "knife-life" (52%), and "other" (60%). At 24 h, 45 days, and 6 months post-treatment, pain intensity dropped to 2.6, 3.5, and 3.1, respectively (p < 0.005). There were no procedure-related complications. CONCLUSIONS: CT-guided percutaneous cryoablation may represent a safe and efficacious option for selected patients with refractory pudendal neuralgia.

Ablation zones and weight-bearing bones: points of caution for the palliative interventionalist.

PURPOSE: To evaluate and classify underlying mechanisms of adverse outcomes after percutaneous computed tomography (CT)-guided cryoablation for palliation of painful musculoskeletal metastatic disease. MATERIALS AND METHODS: Data were collected for patients who underwent CT-guided percutaneous palliative cryoablation for painful musculoskeletal metastatic disease between January 2010 and December 2012. Cases with adverse outcomes or suboptimal response were identified and classified according to the Society of Interventional Radiology (SIR) classification system for complications by outcome and according to underlying mechanism of the outcome as delineated on follow-up examination. RESULTS: There were 61 patients who received ablation for painful musculoskeletal metastatic disease. Six patients with adverse outcomes were identified. Two were minor complications (A, n = 1; B, n = 1), and four were major complications (C, n = 1; D, n = 3). Four patients incurred sequelae related to damage of ancillary structures included in the ablation zone, and two patients developed complete fractures after ablation of lesions in weight-bearing bones. CONCLUSIONS: Complete cryoablation of a painful musculoskeletal metastatic lesion may lead to ancillary damage of adjacent structures or fracture in weight-bearing bones.

Incidence of hypercoagulable events after image-guided percutaneous cryoablation of renal tumors: a single-center experience.

PURPOSE: To identify retrospectively hypercoagulable events that occurred over time in patients who underwent image-guided percutaneous renal cryoablation and compare the incidence with a cohort of patients who underwent surgical partial nephrectomy (PN) during the same time period. MATERIALS AND METHODS: An electronic medical record database was queried for patients who underwent percutaneous image-guided renal mass cryoablation or PN between September 2006 and June 2012. Records were examined for thrombotic events during the year following the procedure in each group. Incidence rates, Kaplan-Meier estimates, and patient demographic variables were compared using the stratified log-rank test and t test for independent samples. RESULTS: The study comprised 114 cryoablation cases. The cumulative incidence of thrombotic events after 1 year was 4.39%. The incidence per 100 person-years was 4.84. There were 105 PN cases. The cumulative incidence of thrombotic events after 1 year was 1.0%. The incidence per 100 person-years was 1.14. The person-time incidence rate difference for these two groups did not reach statistical significance (P = .0894). CONCLUSIONS: The incidence of thrombotic events in patients who underwent percutaneous renal cryoablation in this study was not significantly different than a comparable cohort who underwent surgical PN during the same time period.