Breast cancers with high proliferation and low ER-related signalling have poor prognosis and unique molecular features with implications for therapy.

BACKGROUND: Luminal breast cancers with high proliferation (MKShi) and low ER-related signalling (ERSlo) have a poor prognosis. We investigated treatment responses and molecular features of MKShi/ERSlo tumours to inform potential therapies. METHODS: Gene expression data from patients who received neoadjuvant chemotherapy (NAC) without (MDACC, N = 199) or with pembrolizumab (I-SPY2, N = 40), or endocrine therapy (NET) without (POETIC, N = 172) or with palbociclib (NeoPalAna, N = 32) were analyzed to assess treatment response by MKS/ERS-subgroups. TCGA was used to assess the mutational landscape and biomarkers associated with palbociclib-resistance (Cyclin-E, RBsig, IRPR) and immunotherapy-response (TMB, TILs, T-cell inflamed) by MKS/ERS-subgroups. RESULTS: Compared to MKShi/ERShi tumours, MKShi/ERSlo tumours had higher pathological response rates to NAC (22% vs 8%, p = 0.06) but a higher recurrence risk (4-year metastasis-free survival 70% vs 94%, p = 0.01). MKShi/ERSlo tumours frequently harboured TP53 (34%) and PIK3CA (33%) mutations, and showed high expression of Cyclin-E, RBsig and IRPR, high TMB and elevated TIL and T-cell inflamed metagene expression. MKShi/ERSlo tumours retained high proliferation after NET with or without palbociclib but had higher pathological complete response rates when pembrolizumab was added to NAC (42% vs 21%, p = 0.07). CONCLUSIONS: MKShi/ERSlo tumours have dismal outcomes and are enriched in chemotherapy-sensitive but ET- and palbociclib-resistant tumours. Biomarker analysis and clinical data suggest a potential role for immunotherapy in this group.

Pan-cancer analysis of antibody-drug conjugate targets and putative predictors of treatment response.

BACKGROUND: Antibody-drug conjugates (ADCs) are a rapidly expanding class of compounds in oncology. Our goal was to assess the expression of ADC targets and potential downstream determining factors of activity across pan-cancer and normal tissues. MATERIALS AND METHODS: ADCs in clinical trials (n = 121) were identified through ClinicalTrials.gov, corresponding to 54 targets. Genes potentially implicated in treatment response were identified in the literature. Gene expression from The Cancer Genome Atlas (9000+ cancers of 31 cancer types), the Genotype-Tissue Expression database (n = 19,000 samples from 31 normal tissue types), and the TNMplot.com (n = 12,494 unmatched primary and metastatic samples) were used in this analysis. To compare relative expression across and within tumour types we used pooled normal tissues as reference. RESULTS: For most ADC targets, mRNA levels correlated with protein expression. Pan-cancer target expression distributions identified appealing cancer types for each ADC development. Co-expression of multiple targets was common and suggested opportunities for ADC combinations. Expression levels of genes potentially implicated in ADC response downstream of the target might provide additional information (e.g. TOP1 was highly expressed in many tumour types, including breast and lung cancers). Metastatic compared to primary tissues overexpressed some ADCs targets. Single sample "targetgram" plots were generated to visualise the expression of potentially competing ADC targets and resistance/sensitivity markers highlighting high inter-patient heterogeneity. Off-cancer target expression only partially explains adverse events, while expression of determinants of payload activity explained more of the observed toxicities. CONCLUSION: Our findings draw attention to new therapeutic opportunities for ADCs that can be tested in the clinic and our web platform (https://tnmplot.com) can assist in prioritising upcoming ADC targets for clinical development.

Concomitant ventral hernia repair and bariatric surgery: a retrospective analysis from a UK-based bariatric center.

BACKGROUND: Ventral hernias (VH) are frequently encountered in patients with morbid obesity. Concomitant ventral hernia repair (VHR) and bariatric surgery (BS) is practiced but still controversial. Wound-related complications (seroma, hematoma, wound infection) and hernia recurrence rates are possible inhibitor factors. We aimed to estimate the rate of complications from concomitant BS (laparoscopic Roux-en-Y gastric bypass and sleeve gastrectomy) and VHR and identify patient subgroups at higher risk of complications from synchronous repair. METHODS: A retrospective analysis of successive 106 patients who underwent concomitant BS + VHR at our institute (09/2007 to 09/2015) was performed using data from patients' record. Parameters considered were: type of repair (open/laparoscopic and primary closure/mesh), size and type of hernia (< 5 cm, 5-10 cm, > 10 cm and primary/incisional), patient gender and comorbidities. RESULTS: One hundred and six patients underwent concomitant BS and VHR. Fifty-nine had laparoscopic VHR and 47 open. Hernias recurred in 5 (8.47%) laparoscopic and 7 (14.89%) open VHR. Wound-related complications were common in open (15%) vs. laparoscopic (11.7%) VHR. Patients with VH recurrence included 8 (75%) with defects > 5 cm, 10 (83%) female, and all had BMI > 45. Six patients had wound infection, 5 of which had type 2 diabetes mellitus. Six patients had hematoma, 5 of which underwent mesh repairs. Finally, four patients developed seroma (BMI > 48, defects > 5 cm, laparoscopic mesh repair). CONCLUSION: Synchronous VHR and BS in a bariatric unit is feasible with low recurrence rate. Laparoscopic VHR has lower complication rates than open, apart from seroma formation. Patients with diabetes have higher risk of infection.

Is there a role for enhanced recovery after laparoscopic bariatric surgery? Preliminary results from a specialist obesity treatment center.

BACKGROUND: There has been a relative lack of research on the effect of enhanced recovery in the context of morbid obesity surgery. OBJECTIVES: To determine if the application of enhanced recovery after surgery (ERAS) principles can contribute to reduce postoperative hospital length of stay after bariatric surgery, controlling for other factors that may influence safe discharge on the first postoperative day. SETTING: University teaching hospital, United Kingdom. METHODS: Between February 2011 and December 2014, prospectively collected data on all patients undergoing laparoscopic bariatric surgery under the care of a single surgeon were reviewed. From January 2012, all patients were enrolled in an ERAS protocol and were assessed for fitness for early discharge (within 24 hr from the operation). Baseline patient characteristics and additional concomitant procedures data were compared for patients treated before and after implementation of the ERAS protocol; 30-day readmission data were analyzed for patients discharged on the first postoperative day and those discharged later. The effect of the implementation of the ERAS protocol on discharge on the first postoperative day was analyzed using multivariate analysis, while taking into account the effects of potential confounders (e.g., age, gender, American Society of Anesthesiologists [ASA] grade, concomitant surgical procedures, etc.). RESULTS: Two-hundred and eighty-eight consecutive patients underwent bariatric surgery. Of these, 278 (96.5%) were potentially suitable for early discharge, while 10 (3.5%) patients developed an acute postoperative complication that delayed discharge irrespective of the effect of ERAS. All these patients required a reoperation within 48 hours and therefore were not considered suitable for early discharge and were not included in the statistical analysis. During the entire study period, 100 of 278 (36%) patients were discharged on the first postoperative day, 28.5% after laparoscopic Roux-en-Y gastric bypass (LRYGB) and 60.9% after laparoscopic sleeve gastrectomy (LSG); 178 of 278 (64%) patients were discharged after ≥ 2 days (mean: 2.58, range: 2-5). After implementation of the ERAS protocol in January 2012, the rate of patients discharged on the first postoperative day increased significantly from 1.6% to 39.7% after LRYGB (P<.01). Early discharge increased from 50% to 67.5% after LSG; although this change did not reach statistical significance (P = .294), it nevertheless represents a clinically relevant result. Four (4%) patients were readmitted after having been discharged on the first postoperative day, 10 (5.3%) patients after having been discharged ≥ 2 postoperative days. This difference was not statistically significant (P = .620). CONCLUSIONS: The implementation of an enhanced recovery program after bariatric surgery is feasible, well tolerated, and can significantly reduce the length of hospital stay without increasing readmission rates. Controlling for several possible confounders, implementation of the ERAS protocol remained the strongest predictor of discharge on the first postoperative day after laparoscopic bariatric surgery.

Incidental oesophageal leiomyoma during laparoscopic Roux-en-Y gastric bypass: finding the unexpected does not affect outcomes.

Most bariatric procedures are now performed laparoscopically. Here, we describe a case of incidental oesophageal leiomyoma found during laparoscopic Roux-en-Y gastric bypass (LRYGB). To our knowledge, this is the first such case reported. Our patient was admitted for an elective LRYGB. She had no upper gastrointestinal symptoms, and therefore did not undergo preoperative oesophagogastroduodenoscopy (OGD). During surgery, a hiatus hernia and an incidental oesophageal leiomyoma were found and treated with hernia repair and enucleation. The end outcome was unaffected. We were able to concomitantly treat the unexpected finding of an oesophageal leiomyoma and a hiatus hernia during the LRYGB. The routine use of OGD prior to bariatric surgery is still controversial. While surgeons should be prepared for unexpected pathologies, when performing laparoscopic bariatric surgery, a routine OGD prior to LRYGB is probably not necessary in asymptomatic patients. Laparoscopic enucleation of oesophageal leiomyoma during LRYGB is feasible and safe.

Combined endoscopic-laparoscopic T-tube insertion for the treatment of staple-line leak after sleeve gastrectomy: a simple and effective therapeutic option.

BACKGROUND: Management of staple-line leak after laparoscopic sleeve gastrectomy (LSG) remains controversial and matter of debate. Transforming a leak into a controlled fistula by insertion of a T-tube is a viable option. To minimize surgical dissection, and to facilitate identification of the leak site and insertion of the T-tube, we have developed a combined endoscopic-laparoscopic T-tube (ELT-t) insertion technique. METHODS: Between February 2011 and June 2014, 7 patients presented with staple-line leak and were treated with ELT-t insertion. After laparoscopic dissection of the abscess cavity, a guidewire is passed endoscopically through the leak; a polypectomy snare is anchored to the guidewire and retrieved through the patient mouth. The long arm of a T-tube is eventually secured to the snare and pulled down through the leak. RESULTS: All patients were started on oral feeding with the T-tube in place. Serial water-soluble contrast swallows were performed to check for healing, and the T-tube was clamped as soon as no extravasation of contrast was demonstrated. The tube was removed either during the index admission or in the outpatient clinic. The residual fistula closed successfully after T-tube removal in all but one case with a "spiral-shaped" sleeve and functional distal obstruction. This patient was treated with stent. Patients were discharged home after a mean postoperative hospital stay of 53.3 days (range: 15-87 days). CONCLUSION: In our experience, ELT-t is a valid alternative for the treatment of staple-line leak after LSG. It allows minimizing surgical dissection, and appears to be safe and effective.

Acute mesenteric ischemia and duodenal ulcer perforation: a unique double pathology.

BACKGROUND: Acute mesenteric ischaemia and duodenal perforation are surgical emergencies with serious consequences. Patients presenting with acute mesenteric ischaemia alone face a high mortality rate as high as 60% whereas those presenting with peptic ulcer perforation the mortality rates range from 6-14%. There are very few reported cases of patients presenting with this dual pathology. CASE PRESENTATION: We report a unique case of a 53 year old Italian lady who presented with acute mesenteric ischaemia and duodenal perforation. This is the first report of massive bowel ischaemia and duodenal perforation with no apparent underlying common pathophysiology leading to this presentation. CONCLUSION: Early management in the intensive care unit and appropriate surgical intervention maximised the patient's chances of survival despite the poor prognosis associated with her dual pathology. The rare pathology of the patient described can be explained by two possible hypotheses: peptic ulcer disease causing duodenal ulceration, which precipitated ischaemic infarction of the small bowel. The second hypothesis is the patient developed a stress related ulcer following ischaemic bowel infarction secondary to arterial thrombosis.

Parathyroid carcinoma: the importance of high clinical suspicion for a correct management.

Background. Parathyroid carcinoma is an infrequent clinical entity whose diagnosis is very challenge. Indeed a pre-operative or intraoperative diagnosis of parathyroid carcinoma is reported in less than half cases described in the literature. Patients and Methods. A systematic review of pathological reports of our secondary referral hospital was done. From 2003 to 2011 one hundred and forty-four patients were operated for hyperparathyroidism. One patient with atypical adenoma and three patients with parathyroid carcinoma were included in this paper. Results. An en bloc resection of the tumor was performed in three patients. Two of this patients with diagnosis of parathyroid carcinoma are alive with no evidence of recurrence or metastasis, respectively, 48 and 60 months after the operation; one patient with diagnosis of atypical adenoma died for other disease 16 months after the operation. In the last patient a simple parathyroidectomy was performed. After that histology revealed the diagnosis of parathyroid carcinoma the patient underwent reoperation for left hemithyroidectomy and central compartment lymph node clearance. After 30 months a lung lobectomy was done due to metastasis. Conclusion. Parathyroid carcinoma should be considered in the differential diagnosis of PTH-dependent hypercalcemia because optional outcomes are associated with complete resection of the tumor at the time of initial operation.

Radionuclide evaluation of the lower gastrointestinal tract.

This review outlines the technical aspects and diagnostic performance parameters of nuclear medicine procedures used on patients with disorders of the lower gastrointestinal tract, with the exclusion of techniques using tumor-seeking radiopharmaceuticals. Chronic disorders of the lower gastrointestinal tract often reduce the quality of life because of discomfort from constipation or diarrhea. Five classes of radionuclide procedures are used to characterize these disorders: transit scintigraphy, searches for ectopic gastric mucosa in Meckel's diverticulum, scintigraphy of active inflammatory bowel disease, scintigraphic defecography, and scintigraphy to detect sites of gastrointestinal bleeding. Protocols for these procedures and their relative merit in patient management are discussed, with special emphasis on their potential for semiquantitative assessment of the pathophysiologic parameter investigated. Quantitation is particularly relevant for prognostic purposes and for monitoring the efficacy of therapy.

Efficacy of Nissen fundoplication versus medical therapy in the regression of low-grade dysplasia in patients with Barrett esophagus: a prospective study.

OBJECTIVE: The aim of this study is to compare the effect of medical and surgical treatment on the history of patients with Barrett esophagus (BE) and histologic evidence of low-grade dysplasia (LGD). SUMMARY BACKGROUND DATA: BE is a complication of severe gastroesophageal reflux. It is considered a major risk factor for esophageal adenocarcinoma, which may develop through stages from nondysplastic metaplasia to dysplasia (LGD and high-grade dysplasia). Presently, there are no recommended therapeutic guidelines for patients with LGD. METHODS: Between 1998 through 2003, 6592 patients underwent upper endoscopy; 327 of 6592 (5%) patients had BE, and 35 of 327 (10.7%) had LGD. Nineteen patients with LGD were treated with high-dose proton pump inhibitors, and 16 patients underwent laparoscopic Nissen fundoplication. Endoscopic and histologic follow-up was available in all patients after 18 months. We used multiple logistic regression to examine the effect of the 2 treatments on regression of LGD. RESULTS: LGD was predominant in men (male-to-female ratio: 1.7:1). Mean age was 58 +/- 13.5 years. Sixty percent of patients had no endoscopic evidence of esophagitis. A regression from LGD to BE was observed in 12 of 19 (63.2%) patients in the medical group and in 15 of 16 (93.8%) patients in the surgical group (statistically significant difference). Differences between the 2 groups were statistically significant (P = 0.03). CONCLUSION: The results of our study suggest that surgical treatment may be more effective than medical therapy to modify the natural history of LGD in patients with BE, perhaps because it not only controls acid but also biliopancreatic reflux into the esophagus.

Radionuclide gastroesophageal motor studies.

Disorders of the upper digestive tract have a high impact on modern society, in terms of both direct and indirect health care costs and of social burden. The most common presenting symptom is either dysphagia or dyspepsia. Discriminating specific diagnoses within this wide group of diseases requires sound clinical judgment and application of procedures to distinguish organic from nonorganic disease and to further characterize the functional or motility disturbance of nonorganic diseases. Non-radionuclide-based diagnostic techniques include both noninvasive tests (upper gastrointestinal barium series, ultrasonography, and breath test for gastric emptying) and invasive procedures (fiberoptic endoscopy, esophagogastroduodenoscopy, pharyngeal manometry, stationary esophageal manometry, 24-h pH monitoring, esophageal biliary reflux monitoring, multichannel intraluminal impedance, and electrogastrography). Some of these techniques are not well tolerated by patients or not widely available. Radionuclide transit/emptying scintigraphy provides a means of characterizing exquisite functional abnormalities with a set of low-cost procedures that are easy to perform and widely available, entail a low radiation burden, closely reflect the physiology of the tract under evaluation, are well tolerated and require minimum cooperation by patients, and provide quantitative data for better intersubject comparison and for monitoring response to therapy. Despite the relatively low degree of standardization both in the scintigraphic technique per se and in image processing, these methods have shown excellent diagnostic performance in several function or motility disorders of the upper digestive tract. Dynamic scintigraphy with a radioactive liquid or semisolid bolus provides important information on both the oropharyngeal and the esophageal phases of swallowing, thus representing a useful complement or even a valid alternative to conventional invasive tests (such as stationary esophageal manometry) for evaluating abnormalities of oropharyngoesophageal transit. Clinical applications of esophageal transit scintigraphy include disorders such as nutcracker esophagus, esophageal spasm, noncardiac chest pain of presumed esophageal origin, achalasia, esophageal involvement of scleroderma, and gastroesophageal reflux and monitoring of response to therapy (either medical or surgical treatment of disease-for example, organic disease such as esophageal cancer). Scintigraphy with a radiolabeled test meal represents the gold standard for evaluating gastric emptying, whereas more recent radionuclide methods include dynamic antral scintigraphy and gastric SPECT for assessing gastric accommodation. Clinical applications of gastric-emptying scintigraphy include, among others, evaluation of patients with dyspepsia and evaluation of gastric function in various systemic diseases affecting gastric emptying. The present review includes the proposal of clinical algorithms for evaluating patients with the main disorders of the upper digestive tract. These algorithms, originally derived from available literature, have been developed on the basis of a vast clinical experience in conjunction with the specialists more deeply involved in the care of patients with such disorders (medical and surgical gastroenterologists and nuclear medicine physicians). The role of radionuclide gastroesophageal motor studies is clearly identified in the various steps of patients' management, from the initial diagnostic approach to functional characterization to postoperative follow-up or monitoring of medical therapy.

Does stapled functional end-to-end anastomosis affect recurrence of Crohn's disease after ileocolonic resection?

BACKGROUND/AIMS: Crohn's disease is characterized by a high incidence of perianastomotic recurrence after ileocolonic resection. The influence of anastomotic configuration on the incidence of reoperation was evaluated in patients undergoing resection for Crohn's disease. METHODOLOGY: 106 patients affected by ileocolonic Crohn's disease were divided in two groups: group I with a hand-sewn end-to-side or side-to-side isoperistaltic anastomosis (30 patients) and group II with functional end-to-end anastomosis made with linear staplers (76 patients). RESULTS: The morbidity was 4.7%: 3 complications and a postoperative death occurred in group I and two complications occurred in group II. There were 5 recurrences (16.7%) in the hand-sewn group and 2 recurrences (2.6%) in the stapled group, with a recurrence rate of 3.54 and 0.92, respectively. CONCLUSIONS: Our non-randomized study suggests a better trend toward the functional stapled technique, in terms of recurrence rate. These observations need further investigation with randomized controlled trials, to compare the two different anastomotic procedures.

The use of small intestine submucosa in the repair of paraesophageal hernias: initial observations of a new technique.

BACKGROUND: Recent reports suggest that when laparoscopy is used to repair paraesophageal hernias recurrence rates reach 20% to 40%. Tension-free hernia closure with synthetic mesh reduces recurrence but occasionally results in esophageal injury. We hypothesized that reinforcement of the hiatal closure with small intestine submucosa (SIS) mesh, in some unusually large hernias, might reduce recurrence rates without causing injury to the esophagus. METHODS: From January 2001 to March 2002 we treated 18 large paraesophageal hernias via a laparoscopic approach. In 9 of the largest hernias (one type II and 8 type III, of which 1 was recurrent) the repair was reinforced with SIS mesh (Surgisis, Cook Surgical) and represent the subjects of this study. Nissen fundoplication with gastropexy was performed in all patients. Clinical follow-up ranged from 3 to 16 months (median 8). Every patient was evaluated with barium esophagram or endoscopy or both 1 to 8 months (median 2) postoperatively. RESULTS: The presenting symptoms were postprandial pain/fullness (9 of 9), heartburn (4 of 9), anemia (4 of 9), dysphagia (3 of 9), regurgitation (3 of 9), and chest pain (3 of 9). One patient died of a hemorrhagic stroke within 30 days of the operation. Postoperatively, presenting symptoms resolved (83%) or improved (17%) in each of the remaining 8 patients. One patient required endoscopic dilation for mild dysphagia. Seven of 8 patients had a normal barium esophagram without evidence of hernia. One morbidly obese (body mass index = 47) patient had a small (2 cm) sliding hiatal hernia postoperatively. There were no other complications, and specifically no perforations or mesh erosions. CONCLUSIONS: These observations suggest that the use of SIS in the repair of paraesophageal hernias is safe and may reduce recurrence. Longer follow-up and a randomized study are needed to validate these results.

Expectations and outcomes when moving from open to laparoscopic adrenalectomy: multivariate analysis.

Various authors have suggested that laparoscopic adrenalectomy (LA) leads to better surgical outcomes than open surgery. The debate is still open, however, and indications and limitations of minimally invasive surgery have not been completely established. The objective of our study was to compare surgical outcomes of LA and open adrenalectomy (OA), using multivariate analysis to adjust for potential confounding factors (e.g., size of the lesion, histology). Between 1995 and June 2000 at "Careggi" Hospital in Florence, Italy patients with an indication for adrenalectomy were treated laparoscopically if the lesion was < 10 cm and there was no clinical evidence of malignancy. All 79 patients who underwent LA have been included in this study. Among 152 patients who underwent OA at "La Sapienza" University in Rome, 93 had an adrenal lesion < 10 cm and no clinical evidence of malignancy; they were selected for comparison. Multivariate analysis has been used to analyze the effect of the surgical approach (OA vs. LA) on the surgical outcome, controlling for potential confounders. Multiple logistic regression showed that there is no significant difference in intraoperative outcomes (i.e., surgical time > 2 hours, blood loss > or = 500 ml) between patients operated on through a traditional approach and those who underwent LA. On the other hand, patients operated on laparoscopically have a significantly higher probability than the OA group of experiencing a better recovery from surgery (i.e., require less postoperative analgesics and return to normal activities earlier). The results of the present study show that, although LA does not add much benefit in terms of expected intraoperative outcomes, it dramatically speeds patients' recovery from surgery. The two approaches are complementary and should both be integrated into the technical background of all endocrine surgeons.

Outcomes of laparoscopic Nissen fundoplication in patients with the "hypercontractile esophagus".

HYPOTHESIS: To determine if a hypercontractile esophagus, manifested by high-amplitude peristaltic contractions (HAPCs) or hypertensive lower esophageal sphincter (HLES), affects the outcome of antireflux surgery. DESIGN: Case series. Prospectively maintained database. Direct contact with patients. Mean follow-up 28.7 months. SETTING: University hospital. PATIENTS: Of 643 patients who had antireflux surgery for uncomplicated gastroesophageal reflux disease (GERD), 15 had HAPCs (> or = 150 mm Hg) and 4 HLES (> or = 45 mm Hg). INTERVENTION: Laparoscopic Nissen fundoplication in all patients. MAIN OUTCOME MEASURES: (1) Frequency of hypercontractile esophagus in patients considered for antireflux procedure. (2) Effect of fundoplication on esophageal acid exposure and symptoms. (3) Establish whether dysphagia or chest pain develop after fundoplication. RESULTS: The typical GERD symptoms of heartburn and/or regurgitation occurred in 15 (79%) and 13 (69%) of 19 patients. Dysphagia was present in 5 of 15 patients with HAPCs and in 0 of 4 with HLES; chest pain was found 5 of 15 patients with HAPCs. After fundoplication acid exposure was improved in all (92%, 16/17) but 1 and was totally normal in 10 patients (83%). Heartburn improved in 11(78%) of 14 and resolved in 8 patients (57%) of the 14. Chest pain improved in 4 (80%) of the 5 patients who had it, and developed in 3 (23%) who did not have it preoperatively. In patients with HAPCs, dysphagia improved in 4 (80%) of 5 patients with complete resolution in 3 (60%). New dysphagia developed in 2 (11%) of the 19 patients, 1 in each group. No patient with HLES developed chest pain. CONCLUSIONS: High-amplitude peristaltic contractions or HLES may be associated with GERD in a subset of patients with dysphagia or chest pain. In such patients, a Nissen fundoplication, by effectively controlling GERD, relieves these symptoms in most patients. A hypercontractile esophagus in patients with GERD should not be considered a contraindication to a total fundoplication. The surgeon and the patient should be aware of the risk of developing chest pain after the operation.

The Blue DRAGON--a system for monitoring the kinematics and the dynamics of endoscopic tools in minimally invasive surgery for objective laparoscopic skill assessment.

Minimally invasive surgeiy (MIS) involves a multi-dimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in mastering MIS surgery but may also be used to define objective criteria for characterizing surgical performance. The BIueDRAGON is a new system for acquiring the kinematics and the dynamics of two endoscopic tools along with the visual view of the surgical scene. It includes two four-bar mechanisms equipped with position and force torque sensors for measuring the positions and the orientations (P/O) of two endoscopic tools along with the forces and torques applied by the surgeons hands. The methodology of decomposing the surgical task is based on a fully connected, finite-states (28 states) Markov model where each states corresponded to a fundamental tool/tissue interaction based on the tool kinematics and associated with unique F/T signatures. The experimental protocol included seven MIS tasks performed on an animal model (pig) by 30 surgeons at different levels of their residency training. Preliminary analysis of these data showed that major differences between residents at different skill levels were: (i) the types of tool/tissue interactions being used, (ii) the transitions between tool/tissue interactions being applied by each hand, (iii) time spent while perfonning each tool/tissue interaction, (iv) the overall completion time, and (v) the variable F/T magnitudes being applied by the subjects through the endoscopic tools. Systems like surgical robots or virtual reality simulators that inherently measure the kinematics and the dynamics of the surgical tool may benefit from inclusion of the proposed methodology for analysis of efficacy and objective evaluation of surgical skills during training.