Comparative validation of machine learning algorithms for surgical workflow and skill analysis with the HeiChole benchmark

Purpose: Surgical workflow and skill analysis are key technologies for the next generation of cognitive surgical assistance systems. These systems could increase the safety of the operation through context-sensitive warnings and semi-autonomous robotic assistance or improve training of surgeons via data-driven feedback. In surgical workflow analysis up to 91% average precision has been reported for phase recognition on an open data single-center video dataset. In this work we investigated the generalizability of phase recognition algorithms in a multicenter setting including more difficult recognition tasks such as surgical action and surgical skill. Methods: To achieve this goal, a dataset with 33 laparoscopic cholecystectomy videos from three surgical centers with a total operation time of 22 h was created. Labels included framewise annotation of seven surgical phases with 250 phase transitions, 5514 occurences of four surgical actions, 6980 occurences of 21 surgical instruments from seven instrument categories and 495 skill classifications in five skill dimensions. The dataset was used in the 2019 international Endoscopic Vision challenge, sub-challenge for surgical workflow and skill analysis. Here, 12 research teams trained and submitted their machine learning algorithms for recognition of phase, action, instrument and/or skill assessment. Results: F1-scores were achieved for phase recognition between 23.9% and 67.7% (n = 9 teams), for instrument presence detection between 38.5% and 63.8% (n = 8 teams), but for action recognition only between 21.8% and 23.3% (n = 5 teams). The average absolute error for skill assessment was 0.78 (n = 1 team). Conclusion: Surgical workflow and skill analysis are promising technologies to support the surgical team, but there is still room for improvement, as shown by our comparison of machine learning algorithms. This novel HeiChole benchmark can be used for comparable evaluation and validation of future work. In future studies, it is of utmost importance to create more open, high-quality datasets in order to allow the development of artificial intelligence and cognitive robotics in surgery

CASTLE tumour of the neck: a rare location of a malignant tumour of the thymus

We present the case of a 62-year-old woman who consulted her physician in December 2005, suffering from a mass at the left lower anterior neck with rapid enlargement. Intraoperative frozen section was highly suspicious of a CASTLE tumour (carcinomas showing thymus-like differentiation). Finally, immunohistochemical investigation revealing positivity for CK5/6, c-kit (CD117) and CD5 as well as negativity for thyroglobulin, calcitonin, vimentin and TTF-1 confirmed the diagnosis. Due to lymph node metastases, radiochemotherapy was performed. Fifteen months after the initial diagnosis disseminated pulmonary metastases were found and treated with cisplatin based chemotherapy, which led to a stabilisation of the disease. In June 2008, computed tomography showed progress of the pulmonary metastases, making further chemotherapeutical treatment necessary. Although treatment was changed in October 2008, the staging evaluation in January 2009 revealed further progress of the metastatic disease. Currently, the patient is still alive, but receives no medical treatment at the moment

Endoscopic Stent Placement Can Successfully Treat Gastric Leak Following Laparoscopic Sleeve Gastrectomy If and Only If an Esophagoduodenal Megastent Is Used

Purpose!#!Gastric staple line leakage (GL) is a serious complication of laparoscopic sleeve gastrectomy (LSG), with a specific mortality ranging from 0.2 to 3.7%. The current treatment of choice is stent insertion. However, it is unclear whether the type of stent which is inserted affects treatment outcome. Therefore, we aimed not only to determine the effectiveness of stent treatment for GL but also to specifically clarify whether treatment outcome was dependent on the type of stent (small- (SS) or megastent (MS)) which was used.!##!Patients and methods!#!A single-centre retrospective study of 23 consecutive patients was conducted to compare the outcomes of SS (n = 12) and MS (n = 11) for the treatment of GL following LSG. The primary outcome measure was the success rate of stenting, defined as complete healing of the GL without changing the treatment strategy. Treatment change or death were both coded as failure.!##!Results!#!The success rate of MS was 91% (10/11) compared to only 50% (6/12) for SS (p = 0.006). An average of 2.3 ± 0.5 and 6.8 ± 3.7 endoscopies were required to achieve healing in the MS and SS groups respectively (p < 0.001). The average time to resumption of oral nutrition was shorter in the MS group (1.4 ± 1.1 days vs. 23.1 ± 33.1 days, p = 0.003).!##!Conclusions!#!Stent therapy is only effective and safe for the treatment of GL after LSG if a MS is used. Treatment with a MS may not only increase treatment success rates but may also facilitate earlier resumption of oral nutrition and shorten the duration of hospitalization

Short-Term Outcomes of Surgery for Graves’ Disease in Germany

Background: Surgical treatment of Graves’ disease (GD) has a potentially increased incidence of postoperative hypoparathyroidism, recurrent laryngeal nerve palsy (RLNP) and bleeding. The aim of this study was to evaluate the current extent of surgery for the treatment of GD and its safety as a short-term outcome. Methods: Patients who underwent thyroid resection for GD were identified from the prospective StuDoQ/Thyroid registry. Patient data were retrospectively analyzed regarding demographics, surgical procedures and perioperative outcomes. Statistics were performed with Student’s t-test or Fisher’s exact test and multivariate Cox regression analysis. The level of statistical significance was set at p < 0.05. Results: A total of 1808 patients with GD with a median age of 44 (range 14–85) years were enrolled in a 25-month period by 78 departments, of which 35.7% (n = 645) had an endocrine orbitopathy and 0.1% (n = 6) had thyrotoxic crisis. Conventional open surgery was used in 98.6% of cases and minimally invasive or remote-access approaches were used in 1.4%. Total thyroidectomy was performed in 93.4% of cases (n = 1688). Intraoperative neuromonitoring (IONM) was used in 98.9% (n = 1789) of procedures. In 98.3% (n = 1777) at least one parathyroid gland was visualized and in 20.7% (n = 375) parathyroids were autografted. The rates of unilateral and bilateral transient RLNP were 3.9% (n = 134/3429 nerves at risk) and 0.1% (n = 4/3429 NAR). The rates of transient RLNP tended to be higher when intermittent IONM was used compared to continuous IONM (4.1% vs. 3.4%, p < 0.059). The rate of transient postoperative hypoparathyroidism was overall 29% (n = 525/1808). Multivariate analysis revealed fewer than 300 thyroid resections and fewer than 15 thyroid resections for GD per year, male sex, BMI > 30, autotransplantation of parathyroid glands and previous bilateral thyroid surgery as independent risk factors for postoperative temporary hypoparathyroidism. Reoperations for bleeding (1.3%) were rare. Conclusion: Total thyroidectomy with IONM is safe and currently the most common surgical therapy for GD in Germany. Postoperative hypoparathyroidism is the major complication which should be focused on