Use of right colon vaginoplasty in gender affirming surgery: proposed advantages, review of technique, and outcomes.

INTRODUCTION: Various methods have been described to create a functional neovagina with feminizing (male-to-female) gender affirming surgery. Intestinal vaginoplasty using ileal or colon segments confers natural mucus production and greater canal depth with primary vaginoplasty. In this work we describe an alternative approach to primary and salvage vaginoplasty using right colon. We focus on relative advantages compared to use of other bowel segments, and we review patient outcomes. METHODS: Transgender women who had previously undergone primary vaginoplasty underwent laparoscopic right colon vaginoplasty at our center between 12/2017 and 7/2019. Demographic, medical, outcome, and satisfaction data was collected and retrospectively reviewed. RESULTS: Twenty-two consecutive transgender women patients underwent laparoscopic right colon vaginoplasty. Mean age was 39.3 years. There were two intraoperative complications:1 injury of the ileocolic pedicle, and 1 minor bladder injury. Four of 22 patients (18.2%) had short-term complications (< 30 days): 3 had postoperative ileus/small bowel obstruction and 1 had intra-abdominal hemorrhage. All were managed conservatively. Six of 22 patients (27.3%) experienced a total of 14 long-term complications (> 30 days): 1 developed Crohn's (not involving the neovagina); 1 developed late small bowel obstruction (SBO) (managed conservatively); 5 developed neovagina prolapse; 4 developed stenosis (2 at the vaginal introitus, and 2 had extrinsic obstruction at the recto-vaginal junction (all underwent successful laparoscopic surgical correction); and 3 were diagnosed with diversion neovaginitis (all treated conservatively). All complications were successfully treated with conservative and/or surgical intervention. All (100%) patients reported satisfaction with neovagina function and appearance. CONCLUSION: This is the only outcomes series of transgender women patients who have undergone right colon vaginoplasty, to date. Our study finding suggests that laparoscopic right colon for primary or salvage vaginoplasty has several important advantages over use of Sigmoid colon or Ileum, and is a reliable technique whose complications can be managed successfully, with favorable, satisfactory long-term outcomes.

Adenosquamous carcinoma: An aggressive histologic sub-type of colon cancer with poor prognosis.

BACKGROUND: Studies have reported worse overall survival (OS) for adenosquamous carcinoma (ASC) compared to adenocarcinoma (AC) of the colon, but none have analyzed a national dataset for over 30 years. METHODS: The National Cancer Database was queried from 2004 to 2016 for patients with ASC and AC of the colon. Kaplan-Meier survival analysis was performed to assess OS. Descriptive variables were evaluated using independent T-test and Chi-square analyses. RESULTS: 332 ASC patients were compared to 496,950 AC patients. AC patients were older than ASC patients (68.6 vs. 64.4 years); p < 0.001. Most ASC cancers presented with stage IV (41.3%) and poorly-differentiated disease (57.5%) compared to AC (22.4% and 17.7%). OS of the ASC cohort was 13.9 months. Median OS for stage IV AC versus stage IV ASC was significantly better (14.1 vs. 8.0 months); p < 0.0001. CONCLUSION: This is the largest national database study to compare ASC with AC. Our findings confirm that unlike AC, ASC most frequently presents late stage, as poorly-differentiated lesions, and have worse OS.

Learning curve in robotic colorectal surgery.

With the rapid adoption of robotics in colorectal surgery, there has been growing interest in the pace at which surgeons gain competency, as it may aid in self-assessment or credentialing. Therefore, we sought to evaluate the learning curve of an expert laparoscopic colorectal surgeon who performed a variety of colorectal procedures robotically. This is a retrospective review of a prospective database of 111 subsequent colorectal procedures performed by a single colorectal surgeon. The cumulative summation technique (CUSUM) was used to construct a learning curve for robotic proficiency by analyzing total operative and console times. Postoperative outcomes including length of stay, 30-day complications, and 30-day readmission rates were evaluated. Chi-square and one-way ANOVA (including Kruskal-Wallis) tests were used to evaluate categorical and continuous variables. Our patient cohort had a mean age of 62.4, mean BMI of 26.9, and mean ASA score of 2.41. There were two conversions to open surgery. The CUSUM graph for console time indicated an initial decrease at case 13 and another decrease at case 83, generating 3 distinct performance phases: learning (n = 13), competence (n = 70), and mastery (n = 28). An interphase comparison revealed no significant differences in age, gender, BMI, ASA score, types of procedures, or indications for surgery between the three phases. Over the course of the study, both mean surgeon console time and median length of stay decreased significantly (p = 0.00017 and p = 0.016, respectively). Although statistically insignificant, there was a downward trend in total operative time and postoperative complication rates. Learning curves for robotic colorectal surgery are commonly divided into three performance phases. Our findings contribute to the construction of a reliable learning curve for the transition of colorectal surgeons to robotics. Furthermore, they may help guide the stepwise training and credentialing of new robotic surgeons.

In situ structures of rotavirus polymerase in action and mechanism of mRNA transcription and release.

Transcribing and replicating a double-stranded genome require protein modules to unwind, transcribe/replicate nucleic acid substrates, and release products. Here we present in situ cryo-electron microscopy structures of rotavirus dsRNA-dependent RNA polymerase (RdRp) in two states pertaining to transcription. In addition to the previously discovered universal "hand-shaped" polymerase core domain shared by DNA polymerases and telomerases, our results show the function of N- and C-terminal domains of RdRp: the former opens the genome duplex to isolate the template strand; the latter splits the emerging template-transcript hybrid, guides genome reannealing to form a transcription bubble, and opens a capsid shell protein (CSP) to release the transcript. These two "helicase" domains also extensively interact with CSP, which has a switchable N-terminal helix that, like cellular transcriptional factors, either inhibits or promotes RdRp activity. The in situ structures of RdRp, CSP, and RNA in action inform mechanisms of not only transcription, but also replication.