An expanding role for interventional radiology: Medicare trends in fluoroscopic, endoscopic, and surgical enteric tube placement and maintenance from 2010 to 2018.

BACKGROUND: The purpose of this study is to provide an update on trends in physician volume and payments for enteric tube placement and maintenance procedures by method, provider specialty, and practice setting amongst Medicare beneficiaries from 2010 to 2018. MATERIALS AND METHODS: Claims from the Medicare Part B Physician/Supplier Procedure Summary Master File (PSPSMF) for the years 2010 to 2018 were extracted using current procedural terminology (CPT) codes for gastrostomy and jejunostomy placement, as well as conversion of gastrostomy to gastrojejunostomy, fluoroscopy guided and non-image guided replacement. Total volumes and provider reimbursement were analyzed by provider specialty and practice setting. RESULTS: Volume of de novo placement of all enteric tubes decreased from 157,123 to 106,549 (-32.2%). While endoscopic placement decreased from 133,658 to 81,171 (-39.3%), the volume of fluoroscopic placement increased from 17,999 to 21,277 (18.2%). Fluoroscopic placement was largely performed by interventional radiology (IR) (91.7% in 2018). Surgical placement decreased from 5466 to 4101 (-25.0%). Volume of fluoroscopic replacement increased from 24,799 to 38,470 (55.1%), while non-image guided replacements decreased from 61,377 to 55,116 (-10.2%). Share of both fluoroscopic and non-image guided replacements by advanced practice providers (APPs) more than doubled over this time period. CONCLUSION: De novo placement of enteric tubes decreased from 2010 to 2018, likely related to increased awareness of the complications and limited benefits in scenarios such as end of life care. In contrast to the diminishing volume for gastroenterologists, there was increased participation by IR in both placement and maintenance procedures under fluoroscopic guidance. SUMMARY STATEMENT: Decreasing placement of enteric tubes suggests shifting attitudes and recommendations around end-of-life care. Increase in role by IR/APPs highlights the need for comprehensive care in these patients.

Effects of the MAGIC Guidelines on PICC Placement Volume: Advanced Practice Provider and Physician Trends Among Medicare Beneficiaries From 2010 to 2018.

BACKGROUND. The Michigan Appropriateness Guide for Intravenous Catheters (MAGIC) was published in 2015, recommending more restricted indications for peripherally inserted central catheter (PICC) placement, particularly for those placed by physicians. Changes in PICC placement volume since the publication of MAGIC is largely unknown. OBJECTIVE. The purpose of this article was to study the trends in volume and reimbursement for PICC placement by physicians and advanced practice providers (APPs) for Medicare enrollees from 2010 to 2018 with specific attention to the changes in volume after the publication of MAGIC in 2015. METHODS. Claims from the Medicare Part B Physician/Supplier Procedure Summary Master File for the years 2010-2018 were extracted using the Current Procedural Terminology code for PICC placement. Total volume and payment amounts (for the professional component) were analyzed. Trendline slopes for volume per 100,000 Medicare beneficiaries before and after the 2015 publication of MAGIC were compared. RESULTS. Volume for PICC placement by physicians and APPs steadily declined from 243,837 in 2010 to 130,361 in 2018 (46.5%). The PICC placement volume decreased sharply after the 2015 publication of the MAGIC guidelines. The slope of the trendline for all providers from 2010 to 2015 was -3.4 compared with -7.3 from 2015 to 2018. The change in slope was more pronounced for radiologists (-3.1 to -5.6) than for APPs (0.0 to -1.1). Professional payment per procedure for radiologists decreased from $78.04 in 2010 to $70.17 in 2018, and reimbursement for APPs proportionally decreased from $65.76 to $60.66 during this time. The relative share of PICC placement by radiologists declined from 77.0% in 2010 to 70.6% in 2018, with a corresponding increase in relative share by APPs from 13.5% to 18.4%. The percentage placed in outpatient procedures increased from 15.1% to 18.2%. CONCLUSION. The volume of PICC placements has steadily decreased since 2010, with a sharper decline between 2015 and 2016 corresponding with the publication of the MAGIC evidence-based guidelines. The role of APPs in PICC placement has increased over this time period. CLINICAL IMPACT. The findings of this study suggest that evidence-based guidelines impact clinical practice on a national level.

A ten-year, single institution experience with percutaneous nephrostomy during pregnancy.

PURPOSE: To evaluate the safety and efficacy of percutaneous nephrostomy (PCN) in pregnancy. MATERIALS AND METHODS: PCN tubes were placed during 52 pregnancies in 49 patients from 2008 to 2018. The medical records during pregnancies were retrospectively reviewed for imaging findings, procedural parameters, outcomes of delivery, and complications. RESULTS: The mean gestational age on percutaneous nephrostomy placement was 27 weeks (range, 8-36 weeks). PCN catheters were placed for the following indications: 1) flank or lower abdominal pain (42%), 2) obstructing calculi (37%), 3) pyelonephritis (20%), and 4) obstructing endometrioma (2%). Prior to PCN, retrograde ureteric stenting was performed in 17 of 49 patients (34%) and attempted but failed in 4 patients (8%). Nephrostomy drainage relieved pain completely or significantly in all 12 patients without prior ureteral stenting, but in only 4 of 10 with retrograde ureteric stents. In one patient in whom the ureteral stent had been removed, PCN relieved her flank pain. The mean number of PCN catheter exchanges was 1.6, ranging from 0 to 9, with a mean time interval of 21.3 days between exchanges. There were 29 difficult exchanges due to encrustation in 15 patients with a mean of 20.5 days between exchanges. CONCLUSIONS: PCN drainage is a safe and effective treatment for managing symptomatic hydronephrosis in pregnant patients but is less effective in treating pain when retrograde ureteral stents are in place. Rapid encrustation, seen more commonly in pregnancy, tends to recur in the same patients and requires more frequent exchanges than the general population.

Resident Case Volume Correlates with Clinical Performance: Finding the Sweet Spot.

RATIONALE AND OBJECTIVES: To determine whether the total number of studies interpreted during radiology residency correlates with clinical performance as measured by objective criteria. MATERIALS AND METHODS: We performed a retrospective cohort study of three graduating classes of radiology residents from a single residency program between the years 2015-2017. The total number of studies interpreted by each resident during residency was tracked. Clinical performance was determined by tracking an individual resident's major discordance rate. A major discordance was recorded when there was a difference between the preliminary resident interpretation and final attending interpretation that could immediately impact patient care. Accreditation council for graduate medical education milestones at the completion of residency, Diagnostic radiology in-training scores in the third year, and score from the American board of radiology core exam were also tabulated. Pearson correlation coefficients and polynomial regression analysis were used to identify correlations between the total number of interpreted films and clinical, test, and milestone performance. RESULTS: Thirty-seven residents interpreted a mean of 12,709 studies (range 8898-19,818; standard deviation [SD] 2351.9) in residency with a mean major discordance rate of 1.1% (range 0.34%-2.54%; stand dev 0.49%). There was a nonlinear correlation between total number of interpreted films and performance. As the number of interpreted films increased to approximately 16,000, clinical performance (p = 0.004) and test performance (p = 0.01) improved, but volumes over 16,000 correlated with worse performance. CONCLUSION: The total number of studies interpreted during radiology training correlates with performance. Residencies should endeavor to find the "sweet spot": the amount of work that maximizes clinical exposure and knowledge without overburdening trainees.

Imaging of Intestinal and Multivisceral Transplantation.

Intestinal transplantation has evolved from its experimental origins in the mid-20th century to its status today as an established treatment option for patients with end-stage intestinal failure who cannot be sustained with total parenteral nutrition. The most common source of intestinal failure in both adults and children is short-bowel syndrome, but a host of other disease processes can lead to this common end-point. The development of intestinal transplantation has presented multiple hurdles for the transplant community, including technical challenges, immunologic pitfalls, and infectious complications. Despite these hurdles, the success rate has climbed over the past decades owing to achievements that include improved surgical techniques, new immunosuppressive regimens, and more effective strategies for posttransplant surveillance and management. Nearly 2800 intestinal transplants have been performed worldwide, and current patient and graft survival rates are now comparable to those of other types of solid organ transplantations. As their population continues to increase, it will be increasingly likely that intestinal-transplant patients will seek imaging at sites other than transplant centers. Therefore, it is important that diagnostic and interventional radiologists be familiar with the procedure, its common variations, and the spectrum of postoperative complications. In this article, the authors provide an overview of intestinal transplantation, including the indications, variations, expected postoperative anatomy, and range of potential complications. ©RSNA, 2018.

Do Residency Selection Factors Predict Radiology Resident Performance?

RATIONALE AND OBJECTIVES: The purpose of our study is to determine what information in medical student residency applications predicts radiology residency success as defined by objective clinical performance data. MATERIALS AND METHODS: We performed a retrospective cohort study of residents who entered our institution's residency program through the National Resident Matching Program as postgraduate year 2 residents and completed the program over the past 2 years. Medical school grades, selection to Alpha Omega Alpha (AOA) Honor Society, United States Medical Licensing Examination (USMLE) scores, publication in peer-reviewed journals, and whether the applicant was from a peer institution were the variables examined. Clinical performance was determined by calculating each resident's cumulative major discordance rate for on-call cases the resident read and gave a preliminary interpretation. A major discordance was defined as a difference between the preliminary resident and the final attending interpretations that could immediately impact the care of the patient. A multivariate logistic regression was performed to determine significant variables. RESULTS: Twenty-seven residents provided preliminary reports on call for 67,145 studies. The mean major discordance rate was 1.08% (range 0.34%-2.54%). Higher USMLE Step 1 scores, publication before residency, and election to AOA Honor Society were all statistically significant predictors of lower major discordance rates (P values 0.01, 0.01, and <0.001, respectively). CONCLUSIONS: Overall resident performance was excellent. There are predictors that help select the better performing residents, namely higher USMLE Step 1 scores, one to two publications during medical school, and election to AOA in the junior year of medical school.

Initial Treatment of Unresectable Neuroendocrine Tumor Liver Metastases with Transarterial Chemoembolization using Streptozotocin: A 20-Year Experience.

BACKGROUND: The majority of patients with neuroendocrine tumor liver metastases (NELM) present with multifocal disease and are not surgical candidates. We present our 20-year experience with transarterial chemoembolization (TACE) using streptozotocin (STZ) in patients with initially unresectable NELM. METHODS: Patients with unresectable NELM treated with TACE using STZ at a single institution from 1995 to 2015 were identified after institutional board approval. Imaging was independently reviewed by a radiologist to evaluate for RECIST 1.1 responses. RESULTS: Ninety-one patients with NELM who underwent 474 TACE treatments during the past 20 years were identified. Median age was 62 years, and 54 % of the patients were females. Median number of TACE treatments per patient was four (range 1-22). TACE treatment with STZ was very well tolerated with 10.3 % of treatments being associated with side effects, predominantly transient, including hyper/hypotension, bradycardia, or postembolization syndrome. Median overall survival from the start of TACE was 44 months (5-year OS from TACE 40.8 % and 5-year PFS 20.3 %), and 54 % of the patients who had carcinoid syndrome reported improved symptoms after TACE treatments. Age, grade, liver tumor burden, and ability to undergo multiple TACE treatments were independent predictors of overall survival in multivariable analysis. Chromogranin A levels >115 ng/ml were associated with worse overall survival (p < 0.001). CONCLUSIONS: In patients with unresectable NELM, TACE with STZ is well tolerated with minimal toxicity and can lead to diminished carcinoid syndrome and long-term survival. This is a novel, conservative approach for the initial treatment of unresectable NELM.

The Prognostic Role of Neutrophil-to-Lymphocyte Ratio in Patients with Unresectable Hepatocellular Carcinoma Treated with Radioembolization.

PURPOSE: To assess the prognostic value of neutrophil-to-lymphocyte ratio (NLR) in patients with unresectable intermediate- or advanced-stage hepatocellular carcinoma (HCC) treated with yttrium-90 radioembolization (RE). MATERIALS AND METHODS: Retrospective chart review was performed for 176 patients with intermediate- or advanced-stage HCC treated with RE between August 2000 and November 2012. The appropriate NLR cutoff was determined by receiver operating characteristic curves. Demographic, clinical, radiographic, and pathologic parameters were compared between patients with a normal NLR (< 5) and those with an elevated NLR (≥ 5) before RE. Barcelona Clinic Liver Cancer (BCLC) stage-stratified univariate and multivariate analyses were conducted to determine variables associated with overall survival. RESULTS: Under univariate analyses, patients with a normal NLR were found to have longer survival than individuals with a high NLR in intermediate/advanced-disease and advanced-disease cohorts. A multivariate Cox proportional-hazards model in the advanced-disease group confirmed that elevated NLR, high α-fetoprotein level, and low albumin level were independent predictors of worse survival. CONCLUSIONS: This study provides stage-dependent evidence for the prognostic role of NLR in the radioembolized HCC cohort. Patients with BCLC stage C disease with elevated NLR may not derive benefit from RE, and other intervening modalities should be explored in this subpopulation.

Neutrophil-lymphocyte ratio is a simple and novel biomarker for prediction of survival after radioembolization for metastatic colorectal cancer.

PURPOSE: Previous studies have reported that an elevated preoperative Neutrophil-Lymphocyte Ratio (NLR) is associated with poor prognosis in patients with various solid tumors including colorectal cancer (CRC). Here, we examine whether NLR predicts survival in patients with unresectable CRC metastases undergoing hepatic radioembolization. METHODS: A retrospective review of 104 consecutive patients with unresectable metastatic CRC who were treated with radioembolization after failing first and second-line chemotherapy. RESULTS: Between 2002 and 2012, the median NLR for all patients was 4.6. Using receiver operating curve analysis, there was no difference between using an NLR cut-off of 4.6 or 5. Forty-eight patients had a high NLR of ≥5 and 56 patients had an NLR of <5. Patients in both groups had similar previous extensive chemotherapy and liver-directed interventions. The median survival of patients with high NLR was 5.6 months (range 4.9-7.9 months) compared with 10.6 months (range 8.3-17.0 months) for patients with low NLR; a significant difference was found in overall survival (log-rank test; p = 0.001). Other factors associated with risk of death were extrahepatic spread of disease, presence of pulmonary nodules, previous liver-targeted intervention, and radiographic response. On multivariate analysis, high NLR, progressive radiographic response, and presence of extrahepatic disease remained independently associated with increased risk of death. CONCLUSIONS: NLR is a simply attainable, inexpensive, and useful biomarker to predict outcome in patients with metastatic colorectal cancer receiving radioembolization.

A case-based approach to common embolization agents used in vascular interventional radiology.

OBJECTIVE: The objective of this article is to familiarize the reader with the most commonly used embolic agents in interventional radiology and discuss an approach for selecting among the different embolic agents. This article reviews their properties and uses a case-based approach to explain how to select one. CONCLUSION: A wide variety of embolic agents are available. Familiarity with the available embolic agents and selection of the most appropriate embolic agent is critical in interventional radiology to achieve optimum therapeutic response and avoid undesired, potentially disastrous complications such as nontarget embolization.

Survival and tolerability of liver radioembolization: a comparison of elderly and younger patients with metastatic colorectal cancer.

AIM: To evaluate the outcomes among elderly (≥70 years) and younger patients (<70 years) with liver-dominant metastatic colorectal cancer (mCRC) who received radioembolization (RE) as salvage therapy. METHODS: A retrospective review of 107 consecutive patients with unresectable mCRC treated with RE after failing first- and second-line chemotherapy. RESULTS: From 2002 to 2012, 44 elderly and 63 younger (<70 years) patients received RE. Patients had similar previous extensive chemotherapy and liver-directed interventions. Using modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria, either a stable or a partial radiographical response was seen in 65.8% of the younger compared with 76.5% of the elderly patients. RE was equally well tolerated in both groups and common procedure-related adverse events were predominantly grade 1-2 and of short duration. No significant difference was found with regard to overall median survival between younger [8.4 months; 95% confidence interval (CI) = 6.2-10.6] or elderly patients (8.2 months; 95% CI = 5.9-10.5, P = 0.667). The presence of extrahepatic disease at the time of RE was associated with a significantly worse median survival in both groups. CONCLUSION: Radioembolization appears to be as well tolerated and effective for the elderly as it is for younger patients with mCRC. Age alone should not be a discriminating factor for the use of radioembolization in the management of mCRC patients.

Combined surgical and interventional radiologic management strategies in patients with arterial pseudo-aneurysms after multivisceral transplantation.

BACKGROUND: Multivisceral transplantation has recently evolved to be a life-saving procedure for patients with intestinal failure and complex abdominal pathology. A composite aortic graft is always needed to restore the arterial flow to the transplanted organs. Accordingly, arterial complications can be life-threatening requiring prompt intervention. Herein, we describe innovative technical approaches in seven recipients who developed pseudo-aneurysm (PA) after transplantation. METHODS: With a total of 285 composite visceral transplants, 15 (5.2%) patients experienced vascular complications. Of these, 7 were life-threatening PAs that were diagnosed 61 to 2677 days after transplantation. Due to the anatomic and technical complexity of the allograft vasculature, endovascular techniques were introduced alone (n=2) or in conjunction with surgical intervention (n=5) in an attempt to rescue patients and salvage the transplanted organs. RESULTS: The endovascular and surgical technical approaches used for each of the 7 PA actively bleeding patients was successful in 5 (71%). Of these, 2 (40%) are alive 86 to 117 months after the intervention. The remaining 5 recipients died of recurrent hemorrhage (n=2), liver failure (n=1), and pneumonia (n=1). The cause of death was unknown in the remaining patient. Retransplantation and intra-abdominal infections were major risk factors. Candida was the most common isolated microorganism. CONCLUSIONS: Recipients of composite visceral allografts are at risk of developing life-threatening PAs, particularly in those with early posttransplantation abdominal infections. Prompt multidisciplinary diagnosis and therapeutic approaches are crucial management strategies.

Yttrium-90 radioembolization as a bridge to liver transplantation: a single-institution experience.

PURPOSE: To evaluate our experience with the use of yttrium-90 ((90)Y) radioembolization in maintaining potential candidacy and, in some instances, downstaging hepatocellular carcinoma (HCC) that does not meet Milan criteria for liver transplantation. MATERIALS AND METHODS: A retrospective review of 20 consecutive patients with HCC who were listed to receive a liver transplant and were treated with (90)Y radioembolization as a sole modality for locoregional "bridge" therapy was performed. Demographics, radiographic and pathologic response, survival, and recurrences were examined. RESULTS: Twenty-two (90)Y treatments were performed in 20 patients before transplantation. Median time from first treatment to transplantation was 3.5 months. HCC in 14 patients met the Milan criteria at the time of the first (90)Y treatment, and HCC in six did not. All cases that originally met the Milan criteria remained within the criteria before transplantation, and two of six patients whose disease did not meet the criteria (33%) had their disease successfully downstaged to meet the criteria. Overall, nine patients (45%) had complete or partial radiologic response to (90)Y radioembolization according to modified Response Evaluation Criteria In Solid Tumors. Complete necrosis of tumor with no evidence of viable tumor on pathologic examination was observed in five patients (36%) whose disease met the Milan criteria. CONCLUSIONS: Particularly in regions with long wait list times, (90)Y treatment is effective in maintaining tumor size in potential liver transplantation candidates with HCC. In addition, it can also be considered as a downstaging therapy in select patients before transplantation.

Wireless Connection between Guide Wires and Bone Cement: Extravasated Methyl Methacrylate Mimicking a Retained Guide Wire.

We present the case of a 56-year-old double lung transplant recipient with chest pain who underwent an attempted endovascular retrieval of what was described as a retained guide wire in the azygos vein. After successfully grasping the tip, the object further migrated to the right pulmonary artery complicating the retrieval. It was realized that the "wire" was extravasated methyl methacrylate from a recent percutaneous kyphoplasty. This is believed to be the first report of attempted endovascular retrieval of extravasated methyl methacrylate in the azygos system. We include the details of this case and briefly review the current literature on the management of extravasated methyl methacrylate from vertebral augmentation procedures. Extravasated methyl methacrylate in the venous system is a common finding after vertebral augmentation procedures and any radiopaque stripe arising from a cemented vertebral body should be first described as probable cement leakage.

The role of ultrasonography in determining central venous patency in patients undergoing bowel transplantation.

Ultrasonography (US) is an attractive alternative for invasive studies to evaluate venous patency. However, little data exist concerning the usefulness of US in patients undergoing bowel transplantation. Twenty-five adult patients with bowel transplantation were retrospectively identified with both US and contrast venography (VG) performed preoperatively. The median age was 43 yr, and the median duration of total parenteral nutrition was 36 months. The vessels were evaluated as positive with ≥ 50% stenosis. Among the internal jugular veins and the subclavian veins examined with US (96% of the all sites) and with VG (69%), 66 venous sites were available for comparison. VG confirmed positive in 42% (28/66), while US found positive in 27% (18/66); US had three false positives and 13 false negatives, giving the sensitivity of 54% (95% confidence interval [CI], 34-72) and the specificity of 92% (CI, 77-98). The positive and the negative likelihood ratios weighted by prevalence (42%) were 5 (CI, 1.7-14.3) and 0.37 (CI, 0.23-0.60), respectively. In addition, VG confirmed stenosis in 32% of the right and 50% of the left brachiocephalic veins and 41% of the superior vena cava. US is not a reliable method for assessing the upper body venous system of patients undergoing bowel transplantation.

Patients' instability, emergency response, and outcomes in the radiology department.

BACKGROUND: Inpatients may be at risk of cardiopulmonary instability during radiologic testing. Calling the medical emergency team is one rescue intervention that brings a team of critical care providers to the unstable patient. Little is known, however, about patients' instability and activations of the medical emergency team in the radiology department (RD-MET). OBJECTIVES: To describe the cause of activation of the RD-MET for hospitalized patients, temporal attributes of RD-MET involvement, characteristics of RD-MET patients, and characteristics associated with good and poor outcomes after RD-MET activation. METHODS: Retrospective pilot study of RD-MET calls for 64 inpatients in a tertiary care hospital during 2009. RESULTS: Reasons for RD-MET activation were 39% neurological, 38% cardiac, and 22% respiratory, and nearly half (42%) occurred during a computed tomography scan. Most RD-MET calls were made between 10 am and noon. RD-MET patients had a mean age of 61 (SD, 19) years; 52% were female, and 89% were white. Admitting diagnoses were most commonly neurological (20%), cardiovascular (16%), and abdominal (16%). The most common comorbid conditions were chronic obstructive pulmonary disease (23%) and diabetes (20%). Half of RD-MET inpatients were from a general care unit, and 56% required preexisting oxygen support. After RD-MET involvement, 61% of patients required a higher level of care; 3% died during the MET intervention, and 19% died later in hospitalization. Patients with preexisting comorbid conditions were more likely to have poor outcomes after the RD-MET intervention (P = .001). CONCLUSIONS: RD-MET patients with comorbid conditions, from a general care unit, and at risk for neurological deterioration arrive in the radiology department with potentially underestimated support needs. Greater support in specific time frames and locations may be warranted to improve outcomes.

Yttrium-90 radioembolization for colorectal cancer liver metastases: a single institution experience.

Purpose. We sought to evaluate our experience using yttrium-90 ((90)Y) resin microsphere hepatic radioembolization as salvage therapy for liver-dominant metastatic colorectal cancer (mCRC). Methods. A retrospective review of consecutive patients with unresectable mCRC who were treated with (90)Y after failing first and second line systemic chemotherapy. Demographics, treatment dose, biochemical and radiographic response, toxicities, and survival were examined. Results. Fifty-one patients underwent (90)Y treatments of which 69% were male. All patients had previously undergone extensive chemotherapy, 31% had undergone previous liver-directed therapy and 24% had a prior liver resection. Using RECIST criteria, either stable disease or a partial response was seen in 77% of patients. Overall median survival from the time of first (90)Y treatment was 10.2 months (95% CI = 7.5-13.0). The absence of extrahepatic disease at the time of treatment with (90)Y was associated with an improved survival, median survival of 17.0 months (95% CI = 6.4-27.6), compared to those with extrahepatic disease at the time of treatment with (90)Y, 6.7 months (95% CI = 2.7-10.6 CONCLUSION: (90)Y therapy is a safe locoregional therapy that provides an important therapeutic option to patients who have failed first and second line chemotherapy and have adequate liver function and performance status.

Peripherally inserted central catheter placement using the Sonic Flashlight.

The Sonic Flashlight is an ultrasound (US) device that projects real-time US images into patients with use of a semireflective/transparent mirror. The present study evaluated the feasibility of use of the Sonic Flashlight for clinical peripherally inserted central catheter placements, originally with the mirror located inside a sterile cover (n = 15), then with the mirror outside (n = 11). Successful access was obtained in all cases. Results show that this new design improved visibility, as judged subjectively firsthand and in photographs. The study demonstrated the feasibility of the Sonic Flashlight and the new design to help assure sterility without degrading visibility, allowing further clinical trials involving physicians and nurses.