The Top 100 Most Impactful Articles on the Achilles Tendon According to Altmetric Attention Score and Number of Citations.

Background: Achilles tendon injuries often generate substantial discussion in the mainstream media. The Altmetric Attention Score (AAS) measures the online dialogue pertaining to Achilles tendon research that occurs outside scientific journals, which traditional citation-based metrics fail to capture. Purpose: To characterize the top 100 most-cited Achilles tendon articles and compare them with the 100 Achilles tendon articles with the highest AAS. A secondary goal was to gain an improved understanding of the online dissemination and interpretation of Achilles tendon research through this comparison. Study Design: Cross-sectional study. Methods: The Web of Science Clarivate database was queried to isolate the 100 most-cited Achilles tendon articles, and the Altmetric database was queried to identify the Achilles tendon articles with the top 100 AAS values. Data elements were extracted for each article including study type, study topic, and geographic origin. Results: The Web of Science Clarivate database search yielded 10,890 articles published between 1970 and 2021. The 100 most-cited articles were published in 35 journals, with the American Journal of Sports Medicine being the most prevalent. The mean (±SD) number of citations was 214.5 ± 86.47. The most prevalent study type was laboratory (28.0%). The most prevalent study topic was treatment (41.0%). Of these articles, 72.0% were European. The Altmetric database search yielded 3810 articles published between 1957 and 2021. The AAS of the top 100 articles ranged from 37 to 476 with a mean of 98.17 ± 85.53. The selected articles were published in 39 journals, with the British Journal of Sports Medicine being the most prevalent. The most prevalent study type was randomized controlled trial (25.0%). The most common study topic was treatment (40.0%). Of these articles, 46.0% were European. Conclusion: Our findings suggest that, although the scientific community remains committed to high-impact journals with articles backed by high citation numbers, there is an increasing opportunity to consume Achilles tendon literature through social media.

Adjustable Cortical Fixation Repair Is a Safe and Effective Technique for Quadriceps Tendon Rupture.

Purpose: To report the clinical outcomes of quadriceps tendon repair using adjustable cortical fixation devices at a minimum 2-year follow-up. Methods: A retrospective chart review identified patients who underwent quadriceps tendon repair using adjustable cortical fixation devices between January 2017 and March 2020. Patients with a partial tendon rupture were excluded. Demographic and injury-specific variables were gathered preoperatively and postoperatively from the electronic medical record and patient-reported outcomes (Lysholm Knee Questionnaire, Lower Extremity Functional Scale, and SF-12) were collected via telephone at a minimum of 2 years postoperatively. Results: Fourteen quadriceps tendon repairs were included in a total of 13 patients. The average time to follow-up was 3.5 ± 1.2 years with a range of 1.9 to 5.7 years. The mean age of this cohort was 55.7 ± 11.6 years, and the mean body mass index was 32.9 ± 6.0. Ten injuries (71.4%) were sustained by mechanical fall, 2 patients (14.3%) suffered a direct blow to the knee, and 2 patients (14.3%) reported a noncontact injury mechanism. Thirteen quadriceps ruptures (13/14, 92.9%) underwent surgery within 10 days of their injury. One knee (7.1%) had a postoperative extensor lag of 5°, whereas another knee (7.1%) required a reoperation for manipulation under anesthesia and arthroscopic lysis of adhesions at 3 months' postoperatively. None of the included patients (0.0%) developed a tendon re-rupture, venous thromboembolism, delayed wound healing, surgical-site infection, neuropraxia or nerve injury, hardware irritation, patella fracture, or heterotopic ossification. Conclusions: In this study, adjustable cortical fixation was a safe and effective surgical technique for quadriceps tendon repair, with adequate restoration of quadriceps function and a low rate of adverse events at 2 years postoperatively. Level of Evidence: Level IV, therapeutic case series.

Effect of Poly-L-Lactic Acid Mesh Augmentation on Cyclic Gap Formation in Transosseous Patellar Tendon Repair: A Biomechanical Study.

No previous study has investigated poly-L-lactic acid (PLLA) surgical mesh augmentation in the repair of inferior pole patellar tendon rupture. We compared the biomechanical properties of transosseous patellar tendon repair with PLLA surgical mesh augmentation to transosseous repair without augmentation. Ten matched pairs of cadaveric knees were used. Specimens in each pair were randomized to undergo the transosseous technique alone or the transosseous technique augmented with a PLLA surgical mesh. An inferior pole patellar tendon rupture was simulated and the repair procedure was performed. Specimens were cyclically loaded for 500 cycles. Gap formation was measured using two sensors placed medial and lateral to the repair site. After cyclic loading, load to failure was determined by pulling the tendon at a constant rate until a sudden decrease in load occurred. The primary outcome measure was cyclic gap formation at the medial and lateral sensors. Compared with controls, specimens that underwent PLLA mesh-augmented repair had significantly lower medial gap formation at all testing intervals up to 500 cycles (p < 0.05) and significantly lower lateral gap formation at all testing intervals from 10 to 500 cycles (p < 0.05). Transosseous patellar tendon repair augmented with a PLLA woven mesh device provided significantly greater resistance to gap formation compared with transosseous repair alone. These results suggest that PLLA mesh augmentation of the transosseous technique is biomechanically effective for patellar tendon repair.

Epidemiology and survival factors of appendicular myxofibrosarcoma: a SEER-retrospective study.

Background: The low incidence of myxofibrosarcoma (MFS) makes high power studies difficult to perform. Demographic and prognostic factors for MFS and how they differ from all extremity soft tissue sarcomas (STS) are not well understood. The purpose of this study was to characterize a large cohort of patients with MFS and evaluate epidemiologic and survival factors when compared to all STS. Materials and methods: We performed a retrospective review of the Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2015 to identify 1,440 patients diagnosed with MFS and 12,324 with STS. Survival curves were creased using Kaplan-Meier, and Cox regression analyses were performed to identify hazard ratios (HRs). Results: Overall survival was greater for STS than MFS (79% vs. 67%). Patients with MFS had a higher average age at diagnosis than STS (62 vs. 56), and older age was strongly associated with decreased survivorship for MFS (HR = 7.94). A greater proportion of patients under 30 diagnosed with MFS were female when compared to STS (49.6% vs. 45.4%). The incidence of MFS and STS increased over the 15-year period, with MFS increasing at a greater rate than STS (1.25% vs. 2.59%). Survival increased for patients diagnosed after 2008 for both STS (9.4%) and MFS (13.2%). Conclusions: There are differences between patient demographics and survival factors when comparing MFS to all STS. Monitoring changes in demographic and survival trends for rare STS subtypes like MFS is important to improve diagnostic algorithms and treatment options.

The 50 most impactful articles on the medial ulnar collateral ligament: An altmetric analysis of online media.

The purpose of this study was to use the Altmetric Attention Score to determine the 50 most impactful medial ulnar collateral ligament articles in online media and compare their characteristics to the most-cited medial ulnar collateral ligament articles in the scientific literature. The Altmetric database was queried to identify all published articles about the medial ulnar collateral ligament, and this list was stratified by the Altmetric Attention Score to identify the 50 highest scoring articles. Several data elements were extracted, including article topic, article type, journal name, and the number of online mentions on Facebook, Twitter, news, and other platforms. Each article's geographic origin was determined based on the institutional affiliation of the first author. Our index search yielded 1283 articles published between 1987 and 2020, from which the 50 articles with the highest Altmetric Attention Scores were included for analysis. Altmetric Attention Scores of the top 50 medial ulnar collateral ligament articles ranged from 20 to 482 (median: 32, interquartile range: 20-62). The most common article type was original research (72%), and the most common topic was epidemiology/risk factors (26%). A majority of studies were Level 3 (36%) or Level 4 evidence (36%). Of the top 50 medial ulnar collateral ligament articles, 94% originated from the United States. A few articles had a high Altmetric Attention Score, suggesting that medial ulnar collateral ligament research does not generate consistently high online attention. The lack of Level 1 studies suggests the need for high-level studies on the medial ulnar collateral ligament. Most studies originated in the United States and were published in the American Orthopaedic Society for Sports Medicine-affiliated journals. The medial ulnar collateral ligament articles included in this study differed substantially from a previous report of the most-cited medial ulnar collateral ligament articles in the literature, suggesting that alternative metrics add a unique dimension to understanding the overall impact of published research on the medial ulnar collateral ligament.

The 100 most impactful articles on the rotator cuff: an altmetric analysis of online media.

PURPOSE: The purpose of our study was to use the Altmetric Attention Score (AAS) to evaluate the 100 most impactful articles in online media pertaining to the rotator cuff and compare their characteristics to the most-cited rotator cuff articles in the scientific literature. METHODS: We performed an article extraction using Altmetric Explorer to identify all published articles pertaining to the rotator cuff. The top 100 articles with the highest AAS were included for analysis. Several data elements were extracted for each included article: title, article type, article topic, year of publication, journal name, authors, institutional affiliations, and online mentions (i.e. the number of times the article was mentioned in news, blog, Twitter, Facebook, and Wikipedia sources). The geographic origin of each article was also determined by the institutional affiliation of the first author, which was categorized as American (originating in the United States), European (originating in Europe), or other. RESULTS: The 100 articles with the highest AAS were published between 2009 and 2020, with AAS ranging from 47 to 676 (median: 74.5, 25th percentile: 59.5, 75th percentile: 114.5). Of all online media sources, Twitter correlated most strongly with AAS (r = 0.9007, r2 = 0.8112). The selected articles were most frequently published in the American Journal of Sports Medicine (13), the Journal of Shoulder and Elbow Surgery (11), and the Journal of Bone and Joint Surgery (7). The most common article type was Systematic Review/Meta-Analysis (29%), followed by Randomized Controlled Trial (15%). The top 3 AAS articles were all published by authors based in Europe. CONCLUSION: The most impactful rotator cuff articles in online media generated substantial online attention. These studies were often performed in Europe and tended to be high level of evidence, focusing on treatment of rotator cuff pathology. The rotator cuff articles that produced the most online attention differed from a previous report of the most-cited rotator cuff articles, suggesting that alternative metrics may be used in concert with conventional bibliometrics to obtain a more complete representation of scientific impact.

The top 100 most impactful articles on the anterior cruciate ligament: An altmetric analysis of online media.

Objectives: To identify the top 100 most impactful anterior cruciate ligament articles in online media as measured by the Altmetric Attention Score and compare their characteristics to the most-cited anterior cruciate ligament articles in the scientific literature. Methods: The Altmetric database was queried to identify all published articles pertaining to the anterior cruciate ligament. The search yielded 9445 articles, which were stratified by highest to lowest Altmetric Attention Score. The top 100 articles were included. Collected data included article type, article topic, journal name, and online mentions in news, blogs, Twitter, Facebook, Wikipedia, and other sources. The geographic origin of each article was also determined based on the institutional affiliation of the first author. Results: Altmetric Attention Score of the top 100 anterior cruciate ligament articles ranged from 109 to 2193 (median 172.0, interquartile range 137.5-271.5). Of the 100 articles, 65 were published in three journals: American Journal of Sports Medicine, British Journal of Sports Medicine, and Journal of Orthopaedic & Sports Physical Therapy. The most prevalent article type was original research (60%), followed by systematic review/meta-analysis (18%). The most prevalent article topic was rehabilitation and return to play after anterior cruciate ligament reconstruction (22%), followed by epidemiology/risk factors (16%), injury prevention (14%), and biomechanics of anterior cruciate ligament injuries (14%). Of the top 100 articles, 54% were American, 31% were European, and 15% were published in other countries outside of the United States and Europe. Conclusion: This study used Altmetric Attention Score to identify the 100 most engaged anterior cruciate ligament articles in online media. The characteristics of these articles differed substantially from the most-cited anterior cruciate ligament articles in the literature with regard to article type, article topic, geographic origin, and publication journal. These findings suggest that alternative metrics measure distinct components of anterior cruciate ligament article engagement and add an important dimension to understanding the overall impact of published research on the anterior cruciate ligament.

Failure Rates of Suture Anchor Fixation Versus Transosseous Tunnel Technique for Patellar Tendon Repair: A Systematic Review and Meta-analysis of Biomechanical Studies.

Background: Transosseous tunnel (TO) repair is considered the gold standard for patellar tendon rupture; however, suture anchor (SA) repair has emerged as a viable alternative in recent years. Although both these techniques are used widely in clinical practice, the most biomechanically optimal construct for patellar tendon repair remains unknown. Purpose: To examine published studies on the biomechanical properties of TO and SA fixation for patellar tendon repair in terms of ultimate load to failure and cyclic gap formation. The null hypothesis was that there would be no significant difference in either outcome measure between the groups. Study Design: Systematic review. Methods: A systematic review using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed by searching PubMed, the Cochrane Library, and Embase to identify studies that analyzed the biomechanical properties of SA and TO techniques for repair of a ruptured patellar tendon. The search phrase implemented was "patellar tendon repair." Meta-analysis was performed to provide a quantitative comparison of the 2 techniques with regard to ultimate load to failure and cyclic gap displacement. Weighted averages were calculated for all quantitative outcomes, and outcomes were summarized in a forest plot. A random-effects model was used to account for the heterogeneity among the included studies in the final statistical analysis. Results: Of 875 studies initially screened, the inclusion criteria were met by 7 studies, including 128 cadaveric specimens (66 SA, 62 TO). The pooled analysis from 6 studies reporting on gap displacement revealed a statistically significant difference in favor of SA versus TO fixation (P < .001). Pooled analysis from 7 studies reporting on ultimate load to failure did not reveal a statistically significant difference between the use of SA and TO for tendon repair (P = .465). Conclusion: Our systematic review revealed that the use of SA fixation for patellar tendon repair was associated with lower cyclic gap displacement when compared with TO fixation. There was no significant difference in ultimate load to failure between the repair techniques.

Adjustable Cortical Fixation Device for Quadriceps Tendon Repair: A Cadaveric Biomechanical Study.

BACKGROUND: Adjustable cortical fixation devices have demonstrated utility in orthopaedic applications, such as ankle syndesmosis repair. PURPOSE: To assess the cyclic gap formation of a quadriceps tendon repair technique using an adjustable cortical fixation device compared with repair with knotless suture anchors and suture tape, a modification of conventional suture anchor repair. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen matched pairs of cadaveric knees were used. Specimens in each pair were randomized to undergo either modified suture anchor repair (control) or adjustable cortical fixation repair. The control repair was performed as previously described. The experimental repair was performed using 2 No. 2 FiberWire sutures placed into the quadriceps tendon in a running locked Krackow configuration and 2 adjustable loop devices passed through transosseous tunnels. The lagging strands of the devices were tensioned to seat the cortical fixation buttons at the inferior patellar pole and then tied to the free Krackow strands at the superior pole to complete the repair. The mean plastic gap (permanent tendon displacement that did not recover with cyclic extension) and mean maximum gap (peak displacement that occurred with cyclic knee flexion and partially recovered with extension) were evaluated during cyclic loading for 500 cycles of full knee extension to 90° of flexion. RESULTS: At all testing intervals, the mean plastic gap was significantly smaller for the cortical fixation group versus the suture anchor group (P < .02). Similarly, the mean maximum gap was significantly smaller for the cortical fixation specimens at all testing intervals (P < .01). After cyclic loading, the mean maximum gap was significantly smaller in the cortical fixation group (4.80 ± 1.56 mm) versus the suture anchor group (8.47 ± 1.47 mm; P = < .001). The mean plastic gap was also significantly smaller in the cortical fixation versus the suture anchor group (3.25 ± 1.10 mm vs 6.57 ± 1.62 mm, respectively; P = < .001). CONCLUSION: Quadriceps tendon repair using an adjustable cortical fixation device demonstrated superior biomechanical properties in cyclic displacement testing compared with repair using the suture anchor technique. CLINICAL RELEVANCE: These results suggest that an adjustable cortical fixation device is a biomechanically viable alternative for quadriceps tendon repair.

Factors Related to Advanced Stage of Cancer Presentation in Botswana.

PURPOSE: Botswana, a country with a high prevalence of HIV, has an increasing incidence of cancer-related mortality in the post-antiretroviral therapy era. Despite universal access to free health care, the majority of Botswana patients with cancer present at advanced stages. This study was designed to explore the factors related to advanced-stage cancer presentation in Botswana. METHODS: Patients attending an oncology clinic between December 2015 and January 2017 at Princess Marina Hospital in Gaborone, Botswana, completed a questionnaire on sociodemographic and clinical factors as well as cancer-related fears, attitudes, beliefs, and stigma. Odds ratios (ORs) were calculated to identify factors significantly associated with advanced stage (stage III and IV) at diagnosis. RESULTS: Of 214 patients, 18.7% were men and 81.3% were women. The median age at diagnosis was 46 years, with 71.9% of patients older than 40 years. The most commonly represented cancers included cervical (42.3%), breast (16%), and head and neck (15.5%). Cancer stages represented in the study group included 8.4% at stage I, 19.2% at stage II, 24.1% at stage III, 11.9% at stage IV, and 36.4% at an unknown stage. Patients who presented at advanced stages were significantly more likely to not be afraid of having cancer (OR, 3.48; P < .05), believe that their family would not care for them if they needed treatment (OR, 6.35; P = .05), and believe that they could not afford to develop cancer (OR, 2.73; P < .05). The perception that symptoms were less serious was also significantly related to advanced stage ( P < .05). Patients with non-female-specific cancers were more likely to present in advanced stages (OR, 5.67; P < .05). CONCLUSION: Future cancer mortality reduction efforts should emphasize cancer symptom awareness and early detection through routine cancer screening, as well as increasing the acceptability of care-seeking, especially among male patients.

Patient Factors Associated With Delays in Obtaining Cancer Care in Botswana.

Purpose Delays in diagnosis and treatment of cancers can lead to poor survival. These delays represent a multifaceted problem attributable to patient, provider, and systemic factors. We aim to quantify intervals from symptom onset to treatment start among patients with cancer in Botswana and to understand potential risk factors for delay. Patients and Methods From December 2015 to January 2017, we surveyed patients seen in an oncology clinic in Botswana. We calculated proportions of patients who experienced delays in appraisal (between detecting symptoms and perceiving a reason to discuss them with provider, defined as > 1 month), help seeking (between discussing symptoms and first consultation with provider, defined as > 1 month), diagnosis (between first consultation and receiving a diagnosis, defined as > 3 months), and treatment (between diagnosis and starting treatment, defined as > 3 months). Results Among 214 patients with cancer who completed the survey, median age at diagnosis was 46 years, and the most common cancer was cancer of the cervix (42.2%). Eighty-one percent of patients were women, 60.7% were HIV infected, and 56.6% presented with advanced cancer (stage III or IV). Twenty-six percent of patients experienced delays in appraisal, 35.5% experienced delays help seeking, 63.1% experienced delays in diagnosis, and 50.4% experienced delays in treatment. Patient income, education, and age were not associated with delays. In univariable analysis, patients living with larger families were less likely to experience a help-seeking delay (odds ratio [OR], 0.31; P = .03), women and patients with perceived very serious symptoms were less likely to experience an appraisal delay (OR, 0.45; P = .032 and OR, 0.14; P = .02, respectively). Conclusion Nearly all patients surveyed experienced a delay in obtaining cancer care. In a setting where care is provided without charge, cancer type and male sex were more important predictors of delays than socioeconomic factors.

Comparison of acute toxicities between contemporary forward-planned 3D conformal radiotherapy and inverse-planned intensity-modulated radiotherapy for whole breast radiation.

The use of inverse-planned intensity-modulated radiation therapy for whole breast radiation treatment has become more prevalent, but this may impose an increased cost on the health system. We hypothesized that when applied with the same treatment planning goals, tangential forward-planned field-in-field 3D conformal radiotherapy and tangential inverse-planned intensity-modulated radiotherapy would be associated with comparable toxicities. Women who underwent tangential whole breast irradiation at our institution from 2011 to 2015 planned using either forward-planned field-in-field 3D conformal radiotherapy or intensity-modulated radiotherapy were retrospectively analyzed. Grade 2+ Radiation dermatitis was the primary endpoint. A total of 201 and 212 women had undergone field-in-field 3D conformal radiotherapy and intensity-modulated radiotherapy, respectively. No differences were observed between the two modalities regarding acute radiation dermatitis, breast pain, or fatigue. In a multivariable logistic regression that incorporated the use of boost, hypofractionation, use of chemotherapy, patient positioning, use of a supraclavicular field, and breast planning target volume, intensity-modulated radiotherapy was not correlated with different rates of Grade 2+ radiation dermatitis. This study supports the routine first-line use of field-in-field 3D conformal radiotherapy for whole breast radiation instead of tangential intensity-modulated radiotherapy from the standpoint of equivalence in acute toxicity. Further investigation is needed to assess whether there are subgroups of women who may still benefit from intensity-modulated radiotherapy.

Lung metastases treated with stereotactic body radiotherapy: the RSSearch® patient Registry's experience.

OBJECTIVES: To report overall survival and local control for patients identified in the RSSearch® Patient Registry with metastatic cancer to the lung treated with SBRT. METHODS: Seven hundred two patients were identified with lung metastases in the RSSearch® Registry. Of these patients, 577 patients had SBRT dose and fractionation information available. Patients were excluded if they received prior surgery, radiation, or radiofrequency ablation to the SBRT treated area. Between April 2004-July 2015, 447 patients treated with SBRT at 30 academic and community-based centers were evaluable for overall survival (OS). Three hundred four patients with 327 lesions were evaluable for local control (LC). All doses were converted to Monte Carlo equivalents and subsequent BED Gy10 for dose response analysis. RESULTS: Median age was 69 years (range, 18-93 years). Median Karnofsky performance status (KPS) was 90 (range 25/75% 80-100). 49.2% of patients had prior systemic therapy. Median metastasis volume was 10.58 cc (range 25/75% 3.7-25.54 cc). Site of primary tumor included colorectal (25.7%), lung (16.6%), head and neck (11.4%), breast (9.2%), kidney (8.1%), skin (6.5%) and other (22.1%). Median dose was 50 Gy (range 25/75% 48-54) delivered in 3 fractions (range 25/75% 3-5) with a median BED of 100Gy10 (range 25/75% 81-136). Median OS for the entire group was 26 months, with actuarial 1-, 3-, and 5-year OS of 74.1%, 33.3, and 21.8%, respectively. Patients with head and neck and breast cancers had longer median OS of 37 and 32 months respectively, compared to colorectal (30 months) and lung (26 months) which corresponded to 3-year actuarial OS of 51.8 and 47.9% for head and neck and breast respectively, compared to 35.8% for colorectal and 31.2% for lung. The median LC for all patients was 53 months, with actuarial 1-, 3-, and 5-year LC rates of 80.4, 58.9, and 46.3%, respectively. There was no difference in LC by primary histologic type (p = 0.49). Improved LC was observed for lung metastases that received SBRT doses of BED ≥100Gy10 with 3-year LC rate of 77.1% compared to 45% for lung metastases treated with BED < 100Gy10 (p = 0.01). Smaller tumor volumes (<11 cc) had improved LC compared to tumor volumes > 11 cc. (p = 0.005) Two-year LC rates for tumor volumes < 11 cc, 11-27 cc and > 27 cc were 72.9, 64.2 and 45.6%, respectively. This correlated with improved OS with 2-year OS rates of 62.4, 60.9 and 46.2% for tumor volumes < 11 cc, 11-27 cc and > 27 cc, respectively (p = 0.0023). In a subset of patients who received BED ≥100Gy10, 2-year LC rates for tumor volumes < 11 cc, 11-27 cc and > 27 cc were 82.8, 58.9 and 68.6%, respectively (p = 0.0244), and 2-year OS rates were 66.0, 58.8 and 28.5%, respectively (p = 0.0081). CONCLUSION: Excellent OS and LC is achievable with SBRT utilizing BED ≥100Gy10 for lung metastases according to the RSSearch® Registry data. Patients with small lung metastases (volumes < 11 cc) had better LC and OS when using SBRT doses of BED ≥100Gy10. Further studies to evaluate a difference, if any, between various tumor types will require a larger number of patients.

Renal artery nerve distribution and density in the porcine model: biologic implications for the development of radiofrequency ablation therapies.

Catheter-based renal artery denervation has demonstrated to be effective in decreasing blood pressure among patients with refractory hypertension. The anatomic distribution of renal artery nerves may influence the safety and efficacy profile of this procedure. We aimed to describe the anatomic distribution and density of periarterial renal nerves in the porcine model. Thirty arterial renal sections were included in the analysis by harvesting a tissue block containing the renal arteries and perirenal tissue from each animal. Each artery was divided into 3 segments (proximal, mid, and distal) and assessed for total number, size, and depth of the nerves according to the location. Nerve counts were greatest proximally (45.62% of the total nerves) and decreased gradually distally (mid, 24.58%; distal, 29.79%). The distribution in nerve size was similar across all 3 sections (∼40% of the nerves, 50-100 µm; ∼30%, 0-50 µm; ∼20%, 100-200 µm; and ∼10%, 200-500 µm). In the arterial segments ∼45% of the nerves were located within 2 mm from the arterial wall whereas ∼52% of all nerves were located within 2.5 mm from the arterial wall. Sympathetic efferent fibers outnumbered sensory afferent fibers overwhelmingly, intermixed within the nerve bundle. In the porcine model, renal artery nerves are seen more frequently in the proximal segment of the artery. Nerve size distribution appears to be homogeneous throughout the artery length. Nerve bundles progress closer to the arterial wall in the distal segments of the artery. This anatomic distribution may have implications for the future development of renal denervation therapies.