Growth kinetics and substrate stability during high-temperature molecular beam epitaxy of AlN nanowires.

We study the molecular beam epitaxy of AlN nanowires between 950 °C and 1215 °C, well above the usual growth temperatures, to identify optimal growth conditions. The nanowires are grown by self-assembly on TiN(111) films sputtered onto Al2O3. Above 1100 °C, the TiN film is seen to undergo grain growth and its surface exhibits {111} facets where AlN nucleation preferentially occurs. Modeling of the nanowire elongation rate measured at different temperatures shows that the Al adatom diffusion length maximizes at 1150 °C, which appears to be the optimum growth temperature. However, analysis of the nanowire luminescence shows a steep increase in the deep-level signal already above 1050 °C, associated with O incorporation from the Al2O3substrate. Comparison with AlN nanowires grown on Si, MgO and SiC substrates suggests that heavy doping of Si and O by interdiffusion from the TiN/substrate interface increases the nanowire internal quantum efficiency, presumably due to the formation of a SiNxor AlOxpassivation shell. The outdiffusion of Si and O would also cause the formation of the inversion domains observed in the nanowires. It follows that for optoelectronic and piezoelectric applications, optimal AlN nanowire ensembles should be prepared at 1150 °C on TiN/SiC substrates and will require anex situsurface passivation.

European expert consensus on a structured approach to training robotic-assisted low anterior resection using performance metrics.

AIM: The aim was to develop and operationally define 'performance metrics' that characterize a reference approach to robotic-assisted low anterior resection (RA-LAR) and to obtain face and content validity through a consensus meeting. METHOD: Three senior colorectal surgeons with robotic experience and a senior behavioural scientist formed the Metrics Group. We used published guidelines, training materials, manufacturers' instructions and unedited videos of RA-LAR to deconstruct the operation into defined, measurable components - performance metrics (i.e. procedure phases, steps, errors and critical errors). The performance metrics were then subjected to detailed critique by 18 expert colorectal surgeons in a modified Delphi process. RESULTS: Performance metrics for RA-LAR had 15 procedure phases, 128 steps, 89 errors and 117 critical errors in women, 88 errors and 118 critical errors in men. After the modified Delphi process the final performance metrics consisted of 14 procedure phases, 129 steps, 88 errors and 115 critical errors in women, 87 errors and 116 critical errors in men. After discussion by the Delphi panel, all procedure phases received unanimous consensus apart from phase I (patient positioning and preparation, 83%) and phase IV (docking, 94%). CONCLUSION: A robotic rectal operation can be broken down into procedure phases, steps, with errors and critical errors, known as performance metrics. The face and content of these metrics have been validated by a large group of expert robotic colorectal surgeons from Europe. We consider the metrics essential for the development of a structured training curriculum and standardized procedural assessment for RA-LAR.

European Society of Coloproctology Colorectal Robotic Surgery Training for the Trainers Course - the first pilot experience.

AIM: Currently, there is no established colorectal specific robotic surgery Train the Trainer (TTT) course. The aim was to develop and evaluate such a course which can then be further developed to be incorporated within the planned European Society of Coloproctology (ESCP)/European School of Coloproctology (ESC) robotic colorectal surgery training curriculum. METHOD: After identifying the need for such a course within a training programme, the course was developed by a subgroup of the ESCP/ESC. A scoping literature review was performed and the content and materials for the course were developed by a team consisting of two gastroenterologists with a combined experience of 30 years of facilitating TTT courses, a robotic surgeon and proctor with laparoscopic TTT faculty experience and experienced robotic and laparoscopic colorectal trainers. The course was evaluated by asking delegates to complete pre- and post-course questionnaires. RESULTS: There were eight delegates on the course from across Europe. Delegates increased their knowledge of each of the course learning objectives and identified learning points in order to change practice. The feedback from the delegates of the course was positive across several areas and all felt that they had achieved their own personal objectives in attending the course. CONCLUSION: This pilot robotic colorectal TTT course has achieved its aim and demonstrated many positives. There is a need for such a course and the evaluation processes have provided opportunities for reflection, which will allow the development/tailoring of future robotic colorectal TTT courses to help develop robotic training further.

Rectal Surgery Evaluation Trial: protocol for a parallel cohort trial of outcomes using surgical techniques for total mesorectal excision with low anterior resection in high-risk rectal cancer patients.

AIM: Total mesorectal excision (TME) is the standard of care for rectal cancer, which can be combined with low anterior resection (LAR) in patients with mid-to-low rectal cancer. The narrow pelvic space and difficulties in obtaining adequate exposure make surgery technically challenging. Four techniques are used to perform the surgery: open laparotomy, laparoscopy, robot-assisted surgery and transanal surgery. Comparative data for these techniques are required to provide clinical data on the surgical management of rectal cancers. METHODS: The Rectal Surgery Evaluation Trial will be a prospective, observational, case-matched, four-cohort, multicentre trial designed to study TME with LAR using open laparotomy, laparoscopy, robot-assisted surgery or transanal surgery in high-surgical-risk patients with mid-to-low non-metastatic rectal cancer. All surgeries will be performed by surgeons experienced in at least one of the techniques. Oncological, morbidity and functional outcomes will be assessed in a composite primary outcome, with success defined as circumferential resection margin ≥ 1 mm, TME Grade III and minimal postoperative morbidity (absence of Clavien-Dindo Grade III-IV complications within 30 days after surgery). Secondary end-points will include the co-primary end-points over the long term (2 years), quality of surgery, quality of life, length of hospital stay, operative time and rate of unplanned conversions. DISCUSSION: This will be the first trial to study all four surgical techniques currently used for TME with LAR in a specific group of high-risk patients. The knowledge obtained will contribute towards helping physicians determine the advantages of each technique and which may be the most appropriate for their patients.

European consensus on the standardization of robotic total mesorectal excision for rectal cancer.

AIM: Surgery for rectal cancer is challenging for both technical and anatomical reasons. The European Academy of Robotic Colorectal Surgery (EARCS) provides a competency-based training programme through a standardized approach. However, there is no consensus on technical standards for robotic surgery when used during surgery for rectal cancer. The aim of this consensus study was to establish operative standards for anterior resection incorporating total mesorectal excision (TME) using robotic techniques, based on recommendations of expert European colorectal surgeons. METHOD: A Delphi questionnaire with a 72-item statement was sent through an electronic survey tool to 24 EARCS faculty members from 10 different countries who were selected based on expertise in robotic colorectal surgery. The task was divided into theatre setup, colonic mobilization and rectal dissection, and each task area was further divided into several subtasks. The levels of agreement (A* > 95% agreement, A > 90%, B > 80% and C > 70%) were considered adequate while agreement of < 70% was considered inadequate. Once consensus was reached, a draft document was compiled and sent out for final approval. RESULTS: The average length of experience of robotic colorectal surgery for participants in this study was 6 years. Initial agreement was 87%; in nine items, it was < 70%. After suggested modifications, the average level of agreement for all items reached 94% in the second round (range 0.75-1). CONCLUSION: This is the first European consensus on the standardization of robotic TME. It provides a baseline for technical standards and structured training in robotic rectal surgery.

Expert consensus on a train-the-trainer curriculum for robotic colorectal surgery.

AIM: Robotic techniques are being increasingly used in colorectal surgery. There is, however, a lack of training opportunities and structured training programmes. Robotic surgery has specific problems and challenges for trainers and trainees. Ergonomics, specific skills and user-machine interfaces are different from those in traditional laparoscopic surgery. The aim of this study was to establish expert consensus on the requirements for a robotic train-the-trainer curriculum amongst robotic surgeons and trainers. METHOD: This is a modified Delphi-type study involving 14 experts in robotic surgery teaching. A reiterating 19-item questionnaire was sent out to the same group and agreement levels analysed. A consensus of 0.8 or higher was considered to be high-level agreement. RESULTS: Response rates were 93-100% and most items reached high levels of agreement within three rounds. Specific requirements for a robotic faculty development curriculum included maximizing dual-console teaching, theatre team training, nontechnical skills training, patient safety, user-machine interface training and telementoring. CONCLUSION: A clear need for the development of a train-the-trainer curriculum has been identified. Further research is needed to assess feasibility, effectiveness and clinical impact of a robotic train-the-trainer curriculum.

Sacral nerve stimulation lead implantation in partial sacral agenesis using intra-operative computerized tomography.

AIM: Sacral nerve stimulation (SNS) lead implantation is a straightforward procedure for individuals with intact spinal vertebrae. When sacral anomalies are present, however, the anatomical and radiological reference points used for the accurate placement of the electrode may be absent or difficult to identify. METHOD: We describe an innovative surgical procedure of percutaneous nerve evaluation for SNS in a patient with faecal incontinence secondary to a congenital imperforate anus and partial sacral agenesis using a surgical imaging platform (O-arm system) under neurophysiological control. RESULTS: Using intra-operative CT and neuronavigation, the insertion point at the skin was identified. The lead was introduced into the right-sided S3 foramen and placed at the correct depth. An appropriate motor response was obtained after stimulation and neurophysiological control confirmed that the right S3 root was being stimulated. CONCLUSION: Our experience showed that O-arm guided navigation can be used to overcome the difficulty of SNS lead placement in patients with partial sacral agenesis who have faecal incontinence.

[Standardized access options for colorectal surgery with the da Vinci Xi system]. / Standardisierte Zugangsoptionen für die kolorektale Chirurgie mit dem Da-Vinci-Xi-System.

BACKGROUND: Performing colorectal surgery with previous da Vinci system generations presented some limitations that caused uncertainty for surgeons as they began to apply robotic technologies. The da Vinci Xi system is designed to overcome these limitations and to enable multiquadrant colorectal surgery. OBJECTIVE: The design concept of the da Vinci Xi system and the standardized access for colorectal surgery are explained. MATERIAL AND METHODS: The da Vinci Xi system applies an overhead boom that maximizes the arm workspace, minimizes interference and makes the port placement universal for standardized access. Colorectal approaches have been validated in numerous cadaver models confirming the reproducibility of the standardized access. RESULTS: Standardized access with a straight-line port placement is possible in all colorectal applications. For right-sided hemicolectomy, a transverse abdominal approach as well as a suprapubic port placement are possible. Utilizing the same principles, left-sided colectomy, sigmoid colectomy and low anterior resections can be performed. Proctocolectomy is enabled through boom rotation and a second docking. Only minor arm-to-arm interferences occurred and were easily manageable by the bedside assistant. None of the approaches required rearrangement of the patient cart or swapping arms to different port locations. CONCLUSION: The da Vinci Xi system enables a standardized access for colorectal surgery through a universal straight-line port placement. Learning this standard principle once enables the surgeon to apply it to all colorectal surgeries and shorten the learning curve as well as minimizing stress for both novices and experienced robotic surgeons learning a new surgical robotic platform.

Evaluation of the robotic approach concerning pitfalls in rectal surgery.

INTRODUCTION: The feasibility and advantages of robotic rectal surgery (RRS) in comparison to conventional open or laparoscopic rectal resections have been postulated in several reports. But well-known challenges and pitfalls of minimal invasive rectal surgery have not been evaluated by a prospective, multicenter setting so far. Aim of this study was to analyze the perioperative outcome of patients following RRS especially in regard to the pitfalls such as obesity, male patients and low tumors by a European multicenter setting. METHODS: This prospective study included 348 patients undergoing robotic surgery due to rectal cancer in six major European centers. Clinicopathological parameters, morbidity, perioperative recovery and short-term outcome were analyzed. RESULTS: A total of 283 restorative surgeries and 65 abdominoperineal resections were carried out. The conversion rate was 4.3%, mean blood loss was 191 ml, and mean operative time was 315 min. Postoperative complications with a Clavien-Dindo score >2 were observed in 13.5%. Obesity and low rectal tumors showed no significant higher rates of major complications or impaired oncological parameters. Male patients had significant higher rates of major complications and anastomotic leakage (p = 0.048 and p = 0.007, respectively). DISCUSSION: RRS is a promising tool for improvement of rectal resections. The well-known pitfalls of minimal-invasive rectal surgery like obesity and low tumors were sufficiently managed by RRS. However, RRS showed significantly higher rates of major complications and anastomotic leakage in male patients, which has to be evaluated by future randomized trials.

Short- and mid-term outcomes of robotic-assisted total mesorectal excision for the treatment of rectal cancer. Our experience after 198 consecutive cases.

BACKGROUND: Robot-assisted total mesorectal excision is a safe alternative for rectal cancer treatment. Nevertheless, substantial data is still missing. Our aim was to assess the perioperative and oncological outcomes of the routine use of the robotic-assisted approach for rectal cancer treatment. PATIENTS AND METHODS: 198 Consecutive robotic rectal resections were performed between January 2011 and April 2015 in patients with stage I-IV disease. We prospectively evaluated peri and postoperative data, pathological findings and mid-term oncological outcomes. RESULTS: 36 Abdominoperineal Amputations, 28 High Anterior Resections, 131 Low Anterior Resections and 3 Hartmann operations were performed. Mean age, ASA, BMI and distance form anal verge were respectively 67.5 years, ASA II, 26.95 kg/m(2) and 5.9 cm. 71.2% Patients received neoadjuvant therapy. Mean OR time was 294 minutes. Conversion occurred in 4.5%. Mean postoperative stay was 8 days. 36 Patients required blood transfusion with a mean of 162 ml. Complications Clavien III-IV were 12.1%. 8 complete responses were observed, 50 UICC class I, 84 class II, 51 class III and 13 class IV. Mean lymph node harvested were 11.7. Mean distal margin was 3.3 cm. 11 Circumferential margins were affected in UICC class III-IV patients. Postoperative mortality was 0.5%. Local recurrence was observed in 5% patients. Median follow-up was 27.6 months. LIMITATIONS: Single institution descriptive study. CONCLUSIONS: The routine use of robotic assisted laparoscopic surgery may help to achieve lower conversion rates with lower ventral hernia rates and similar oncological outcomes using a minimally invasive approach in a non-selected group of patients with non-selected rectal tumours.