Anorectal Anatomy Quiz: Practical Review

Understanding anorectal and pelvic floor anatomy can be challenging but is paramount for every physician managing patients with anorectal pathology. Knowledge of anorectal anatomy is essential for managing benign, malignant, traumatic, and infectious diseases affecting the anorectum. This quiz is intended to provide a practical teaching guide for medical students, medical and surgical residents, and may serve as a review for practicing general surgeons and specialists.

Leaf trait variation during ontogeny in the endangered Brazilian rosewood tree

Knowledge of plant responses to environmental heterogeneity during ontogeny is important to elucidate the changes that occur to promote resource capture in tropical forests. We tested the hypothesis that expression changes in leaf metamer traits of Brazilian rosewood (Dalbergia nigra), from seedlings to emergent canopy trees, occur as new microclimate environments are achieved. We also tested the hypothesis that increased light heterogeneity in the understorey leads to higher plasticity in leaf traits of seedlings and saplings than in sun-exposed metamers of emergent trees subject to stressful conditions. We compared leaf metamer traits of 53 individuals including seedlings, saplings and emergent trees. We also evaluated the light heterogeneity in vertical strata and the variations in leaf traits within individuals (among metamers of the same individual). These were associated with height of the individuals. Compared to understorey plants, emergent trees presented larger metamers, with lower specific leaf area (SLA), lower investment in leaf area per total dry mass of metamer (LAR_m ), lower specific petiole length (SPL) and lower specific internode length (SIL). Higher phenotypic variation within individuals was observed in seedlings, which decreased as the trees grew taller. The results suggest the integration of ontogenetic changes in leaf traits under new microclimate conditions as the plants reach different vertical strata in the forest. Additionally, our results support the hypothesis that increased light heterogeneity in the understorey shaped higher phenotypic variation within individuals in juveniles and that stressful conditions in sun-exposed leaf metamers of emergent trees led to increased phenotypic stability.

Update on Minimally Invasive Surgical Approaches for Rectal Cancer

PURPOSE OF REVIEW

This review aims to clarify the current role of minimally invasive surgery in the treatment of rectal cancer, highlighting short- and long-term outcomes from the latest trials and studies.

RECENT FINDINGS

Data from previous trials has been conflicting, with some failing to demonstrate non-inferiority of laparoscopic surgical resection of rectal cancer compared to an open approach and others demonstrating similar clinical outcomes. Robot-assisted surgery was thought to be a promising solution to the challenges faced by laparoscopic surgery, and even though the only randomized controlled trial to date comparing these two techniques did not show superiority of robot-assisted surgery over laparoscopy, more recent retrospective data suggests a statistically significant higher negative circumferential resection margin rate, decreased frequency of conversion to open, and less sexual and urinary complications. Minimally invasive surgery techniques for resection of rectal cancer, particularly robot-assisted, offer clear short-term peri-operative benefits over an open approach; however, current data has yet to display non-inferiority in terms of oncological outcomes.

Clinical Outcomes Following Single vs. Multiple Vessel Living-Donor Kidney Transplantation: A Retrospective Comparison of 210 Patients

Background: The use of living-donor kidney allografts with multiple vessels continues to rise in order to increase the donor pool. This requires surgeons to pursue vascular reconstructions more often, which has previously been associated with a higher risk of developing early post-transplant complications. We therefore wanted to investigate the prognostic role of using living-donor renal allografts with a single artery (SA) vs. multiple arteries (MA) at the time of transplant.

Methods: We retrospectively analyzed a cohort of 210 consecutive living-donor kidney transplants performed between January, 2008 and March, 2019, and compared the incidence of developing postoperative complications and other clinical outcomes between SA vs. MA recipients.

Results: No differences were observed between SA (N = 161) and MA (N = 49) kidneys in terms of the incidence of developing a postoperative (or surgical) complication, a urologic complication, hospital length of stay, delayed graft function, estimated glomerular filtration rate at 3 or 12 mo post-transplant, and graft survival.

Conclusions: The use of live-kidney allografts with MA requiring vascular reconstruction shows excellent clinical outcomes and does not increase the risk of developing postoperative complications or other adverse outcomes when compared with SA renal allografts.

Hand-assisted laparoscopic nephrectomy in a high risk overweight donor with left-sided IVC, and previous abdominal surgery

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Surgical planning based on preoperative CTA is necessary in patients with vascular anomalies in order to avoid complications.

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Intrabdominal adhesions are common in patients with previous abdominal surgery and can affect the surgical approach for donor nephrectomy.

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Considering the extension of the donor eligibility criteria, it is expected to see cases with congenital vascular anomalies.

Introduction

The extension of donor eligibility criteria represents one of the possible ways to increase the organ shortage, thus decreasing the waiting time for kidney transplantation. Expectedly, this strategy is associated with a growing number of more technically demanding living donor nephrectomy procedures requiring careful assessment, and sound surgical experience in order to avoid intraoperative complications.

Case presentation

After a thorough evaluation through preoperative imaging, we performed a hand-assisted left laparoscopic living donor nephrectomy in a 56 year-old overweight patient with history of prior abdominal surgery, harboring a left-sided inferior vena cava (IVC).

Discussion/conclusion

This case describes our comprehensive approach in this complex surgical scenario to preserve donor safety and provide an optimal kidney graft.

Incidence of Tomato spotted wilt virus (Bunyaviridae) and Tobacco Thrips in Virginia-Type Peanuts in North Carolina

Virginia-type peanut (Arachis hypogaea) cultivars were monitored for incidence of Tomato spotted wilt virus (TSWV) and abundance of Frankliniella fusca, the tobacco thrips, in North Carolina during 1995 and 1996. A preliminary evaluation of 225 peanut genotypes for TSWV-resistant or -tolerant genotypes was conducted in 1995. The incidence of TSWV in cultivar NC-9 was twice that of cultivar NC-V11. In 1996, field trials designed to evaluate TSWV susceptibility were conducted with three widely grown commercial peanut cultivars in North Carolina. They were NC-9, NC-V11, and NC-12C, a newly released cultivar. A randomized complete block design was utilized at three locations. Disease incidence was evaluated weekly from 2 weeks postplanting until 2 weeks prior to harvest. Mechanical inoculation of the three cultivars resulted in no difference in relative leaf virus titer as determined from optical density readings following DAS-ELISA for 4 successive weeks beginning at 13 days postinoculation. NC-9 ranked highest in incidence of disease (7%), followed by NC-12C (6%) and NC-V11 (5%). Thrips counts were greatest on NC-V11, followed by NC-9 and NC-12C. Disease incidence overall was 5.96%, but ranged from 3.08 to 11.15% among the three sites. Yield was affected by the temporal occurrence of symptoms beginning at the fifth week postplanting. Greatest yield losses occurred in those plants with the earliest visible foliar symptoms.