Preceptorship in robotic colorectal surgery: experience from the Australian private sector.

This article describes a post-fellowship preceptorship training program to train sub-specialty colorectal surgeons in gaining proficiency in robotic colorectal surgery using a dual-surgeon model in the Australian private sector. The Australian colorectal surgeon faces challenges in gaining robotic colorectal surgery proficiency with limited exposure and experience in the public setting where the majority of general and colorectal surgery training is currently conducted. This training model uses graded exposure with a range of simulation training, wet lab training, and clinical operative cases to progress through both competency and proficiency in robotic colorectal surgery which is mutually beneficial to surgeons and patients alike. Ongoing audit of practice has shown no adverse impacts.

Modes of carbon dioxide delivery during laparoscopy generate distinct differences in peritoneal damage and hypoxia in a porcine model.

BACKGROUND: Insufflation with CO2 can employ continuous flow, recirculated gas and/or additional warming and humidification. The ability to compare these modes of delivery depends upon the assays employed and opportunities to minimize subject variation. The use of pigs to train colorectal surgeons provided an opportunity to compare three modes of CO2 delivery under controlled circumstances. METHODS: Sixteen pigs were subjected to rectal resection, insufflated with dry-cold CO2 (DC-CO2) (n = 5), recirculated CO2 by an AirSeal device (n = 5) and humidification and warming (HW-CO2) by a HumiGard device (n = 6). Peritoneal biopsies were harvested from the same region of the peritoneum for fixation for immunohistochemistry for hypoxia-inducible factor 1 alpha (HIF-1α) and scanning electron microscopy (SEM) to evaluate hypoxia induction or tissue/cellular damage, respectively. RESULTS: DC-CO2 insufflation by both modes leads to significant damage to mesothelial cells as measured by cellular bulging and retraction as well as microvillus shortening compared with HW-CO2 at 1 to 1.5 h. DC-CO2 also leads to a rapid and significant induction of HIF-1α compared with HW-CO2. CONCLUSIONS: DC-CO2 insufflation induces substantive cellular damage and hypoxia responses within the first hour of application. The use of HW-CO2 insufflation ameliorates these processes for the first one to one and half hours in a large mammal used to replicate surgery in humans.

Modeling open surgery in mice to explore peritoneal damage, carbon dioxide humidification and desmoidogenesis.

BACKGROUND: The exposure of the peritoneum to desiccation during surgery generates lasting damage to the mesothelial lining which impacts inflammation and tissue repair. We have previously explored open abdominal surgery in mice subjected to passive airflow however, operating theatres employ active airflow. Therefore, we sought an engineering solution to recapitulate the active airflow in mice. Similarly, to the passive airflow studies we investigated the influence of humidified-warm carbon dioxide (CO2) on this damage in the context of active airflow. Additionally, we addressed the controversial role of surgery in exacerbating desmoidogenesis in a mouse model of familial adenomatous polyposis. METHODS: An active airflow mouse-operating module manufactured to produce the equivalent downdraft airflow to that of a modern operating theatre was employed. We quantified mesothelial cell integrity by scanning electron microscopy (SEM) sampled from the peritoneal wall that was subjected to mechanical damage or not, with and without the delivery of humidified-warm CO2. To explore the role of open and laparoscopic surgery in the process of desmoidogenesis we crossed Apcmin/ + C57Bl/6 mice with p53 +/- mice to generate animals that developed desmoid tumors with 100% penetrance. RESULTS: One hour of active airflow generates substantial damage to peritoneal mesothelial cells and their microvilli as measured at 24 h post intervention, which is significantly greater than that generated by passive airflow. Use of humidified-warm CO2 mostly protects the mesothelium that had not experienced additional mechanical (surgical) damage at 24 h. Maximal damage was evident in all treatment groups regardless of flow or use of gas. At day 10 mechanically-damaged peritoneum remains in mice but is essentially repaired in the gas-treated groups. Regarding desmoidogenesis, operating procedures did not increase the frequency of desmoid tumors but their frequency correlated with time following surgery but not age of mice. CONCLUSIONS: Active airflow generates more peritoneal damage than passive airflow and is reduced significantly by the use of humidified-warm CO2. Introduced peritoneal damage is largely repaired in mice by day 10 with gas. Desmoid tumor incidence is not increased substantially by surgery itself but rises over time following surgery compared to non-surgery mice.

Tumor-Infiltrating Lymphocyte Function Predicts Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer.

PURPOSE: The presence of tumor-infiltrating lymphocytes (TILs) in tumors is superior to conventional pathologic staging in predicting patient outcome. However, their presence does not define TIL functionality. Here we developed an assay that tests TIL cytotoxicity in patients with locally advanced rectal cancer before definitive treatment, identifying those who will obtain a pathologic complete response (pCR). We also used the assay to demonstrate the rescue of TIL function after checkpoint inhibition blockade (CIB). PATIENTS AND METHODS: Thirty-four consecutive patients were identified initially, with successful completion of the assay before surgery in those 17 patients who underwent full treatment. An in vitro cytotoxic assay of rectal cancer tumoroids cocultured with patient-matched TILs was established and validated. Newly diagnosed patients were recruited with pretreatment biopsy specimens processed within 1 month. Evaluation of TIL-mediated tumoroid lysis was performed by measuring the mean fluorescence intensity of cell death marker, propidium iodide. CIB (anti-programmed cell death protein 1 [anti-PD-1] antibody) response was also assessed in a subset of patient specimens. RESULTS: Six of the 17 patients achieved an objective pCR on final evaluation of the resected specimen after neoadjuvant chemoradiotherapy. Cytotoxic killing identified the pCR group with a higher mean fluorescence intensity (27,982 [95% CI, 25,340 to 30,625]) compared with the non-pCR cohort (12,428 [95% CI, 9,434 to 15,423]; p < .001). Assessment of the effectiveness of CIB revealed partial restoration of cytotoxicity in TILs with increased PD-1 expression with anti-PD-1 antibody exposure. CONCLUSION: Evaluating TIL function can be undertaken within weeks of the diagnostic biopsy, affording the potential to alter patient management decisions and refine selection for a watch-and-wait protocol. This cytotoxic assay also has the potential to serve as a platform to assist in the additional development of CIB.

Surgery for Locally Recurrent Rectal Cancer: Tips, Tricks, and Pitfalls.

Rectal cancer can recur locally in up to 10% of the patients who undergo definitive resection for their primary cancer. Surgical salvage is considered appropriate in the curative setting as well as select cases with palliative intent. Disease-free survival following salvage resection is dependent upon achieving an R0 resection margin. A clear understanding of applied surgical anatomy, appropriate preoperative planning, and a multidisciplinary approach to aggressive soft tissue, bony, and vascular resection with appropriate reconstruction is necessary. Technical tips, tricks, and pitfalls that may assist in managing these cancers are discussed and the roles of additional boost radiation and intraoperative radiation therapy in the management of such cancers are also discussed.