Artificial intelligence for phase recognition in complex laparoscopic cholecystectomy.

BACKGROUND: The potential role and benefits of AI in surgery has yet to be determined. This study is a first step in developing an AI system for minimizing adverse events and improving patient's safety. We developed an Artificial Intelligence (AI) algorithm and evaluated its performance in recognizing surgical phases of laparoscopic cholecystectomy (LC) videos spanning a range of complexities. METHODS: A set of 371 LC videos with various complexity levels and containing adverse events was collected from five hospitals. Two expert surgeons segmented each video into 10 phases including Calot's triangle dissection and clipping and cutting. For each video, adverse events were also annotated when present (major bleeding; gallbladder perforation; major bile leakage; and incidental finding) and complexity level (on a scale of 1-5) was also recorded. The dataset was then split in an 80:20 ratio (294 and 77 videos), stratified by complexity, hospital, and adverse events to train and test the AI model, respectively. The AI-surgeon agreement was then compared to the agreement between surgeons. RESULTS: The mean accuracy of the AI model for surgical phase recognition was 89% [95% CI 87.1%, 90.6%], comparable to the mean inter-annotator agreement of 90% [95% CI 89.4%, 90.5%]. The model's accuracy was inversely associated with procedure complexity, decreasing from 92% (complexity level 1) to 88% (complexity level 3) to 81% (complexity level 5). CONCLUSION: The AI model successfully identified surgical phases in both simple and complex LC procedures. Further validation and system training is warranted to evaluate its potential applications such as to increase patient safety during surgery.

[PANCREATIC NEUROENDOCRINE TUMORS (PNET): THE DILEMMA OF SURGERY VS. WATCHFUL WAITING APPROACH].

INTRODUCTION: Neuroendocrine tumors (NEN) originate from hormone producing cells located in various organs and tissues. NEN are unique tumors in terms of their diverse and particular clinical presentations, growth pattern, location and relatively good prognosis. NEN can be either secreting or non-secreting tumors. The clinical presentation and symptoms are according to the specific hormone produced by the tumor. A non-secreting tumor will eventually cause symptoms that relate to a mass-effect or a metastatic disease. There are various familial and genetic syndromes that are related to NEN. The most common neuroendocrine genetic syndrome is Multiple Endocrine Neoplasia syndrome type 1 (MEN 1). The clinical approach and treatment of NEN are unlike any other cancer. The gold standard management is surgery but unlike other cancerous diseases, surgical intervention is also indicated in cases of metastatic disease. There are several surgical approaches, and they all depend on tumor size, location, grade, stage, lymph node involvement, remote metastases and patients' age and comorbidities. Besides surgery, some cases are also treated with systemic therapies such as Somatostatin analogues, chemotherapy, immunotherapies, targeted therapies and occasionally radiation therapy is used. In the last decade there is a significant increase in the number of patients diagnosed with small non-secreting pancreatic tumors (PNET) due to advanced imaging techniques and diagnostic tools. This incidental increase is the reason for the emerging dilemma of whether to operate or merely conduct a watchful waiting policy. Small non-secreting tumors are commonly not considered malignant and thus the question is if surgery is always the right approach. The benefits of surgery must be carefully considered against the potential damage that may occur during these complex and radical procedures. Moreover, new and progressive systemic pharmacological therapies are now available to efficiently suppress tumor hormonal secretion. Recent studies have challenged surgery as the only treatment of choice, and in some cases suggest conservative treatment and follow up. The aim of this present literature review is to describe PNET diagnostic tools and evaluation, and to examine the different approaches of PNET treatment.

The outcome of transanal endoscopic microsurgery and adjuvant radiotherapy in patients with high-risk T1 rectal cancer.

Introduction: Transanal endoscopic microsurgery (TEM) is considered the technique of choice for adenoma and low-risk T1 rectal cancer. The adequacy of such treatment for high-risk T1 tumours, however, is still controversial. The aim of the study is to evaluate our results with local excision of high-risk T1 cancers. and Methods: Demographic, clinical data pertaining to patients undergoing TEM for T1 rectal cancer between 1999 and 2015 was retrospectively collected. Long-term outcomes were assessed for the entire cohort. Patients were classified into two groups: favourable and high-risk cancer features. Results: Three hundred and fifty-five TEM procedures were recorded in the study period. Forty-three patients were included in the present study. There were 20 females and 23 males, the median age was 69 ± 9. The median tumour distance from the anal verge was 6 cm (range 1-13 cm). Post-operative histopathology showed well/moderately differentiated T1 adenocarcinoma in 30 patients and poorly differentiated in 13. The overall survival for patients with favourable and high-risk features groups were 93.5% and 77%, respectively, while the local recurrence (LR) was 3.5% and 23.1%, respectively. Nine patients with high-risk features received adjuvant radiotherapy; one (11.1%) of them experienced LR. Conclusions: Local excision by TEM augmented by adjuvant radiotherapy may be a feasible alternative for selected patients with high-risk T1 rectal cancer. The addition of radiotherapy seems to decrease the rates of LR.

Transanal endoscopic microsurgery under spinal anaesthesia.

BACKGROUND: Transanal endoscopic microsurgery (TEM) is considered the procedure of choice for rectal adenomas non-amendable for endoscopic excision and for early rectal cancer. TEM may gain more importance in patients who are considered unfit for major surgery. The option of spinal anaesthesia may offer many advantages for patients undergoing TEM while maintaining the principles of complete tumour excision. The aim of this study is to report the outcome of patients undergoing TEM under spinal anaesthesia. METHODS: Demographic and clinical data pertaining patients undergoing TEM under spinal anaesthesia between 2004 and 2015 were retrospectively collected. RESULTS: A total of 158 TEM procedures were recorded in the study period. Twenty-three patients (15%) underwent the procedure under spinal anaesthesia and were included in the study; 13 of them were male and ten were female. The mean age of the patients was 69.1 ± 10.6 years. Seventeen (74%) rectal lesions were adenomas, two (9%) were adenocarcinoma and four (17%) had involved margins after polypectomy. The mean tumour size was 2.1 cm (range, 0.5-3). Distance from the anal verge was 7.7 ± 2.2 cm. Seventeen (74%) lesions were in the posterior wall. The operative time was 73 min (range, 46-108) No adverse anaesthesia-related events were recorded, and the post-operative pain was reduced. The median time of hospitalisation was 2 days (range, 1-4). No major complications were noted, and the minor complications were treated conservatively. The surgical margins were free of tumour in all cases. CONCLUSION: TEM under spinal anaesthesia had short duration of surgery, no increase in operative and post-operative complications or hospital length of stay. Avoiding the use of general anaesthesia, in such challenging procedure, may open new opportunities for patients determined to be unfit for general anaesthesia.

Factors associated with the location of local rectal cancer recurrence and predictors of survival.

PURPOSE: The location of locally recurrent rectal cancer (LRRC) may influence survival. This study examines factors affecting the location of LRRC, the effect of LRRC location on survival, and predictive factors for survival in patients with LRRC. METHODS: Patients undergoing initial proctectomy and subsequent management of LRRC at the Cleveland Clinic (1980-2011) were included. Data regarding index surgery, LRRC, and survival were obtained from a prospectively maintained database. RESULTS: One hundred and fifty-seven patients were identified with a mean follow-up 59.8 ± 50.1 months and time to LRRC of 31.7 ± 30.1 months. Sixty patients underwent surgery with curative intent. Anastomotic leak and retrieving less than 12 lymph nodes at index proctectomy were associated with posterior (P = 0.019) and lateral (P = 0.036) recurrences, respectively. Having an axial relative to an anterior, posterior, or lateral recurrence was associated with improved overall survival (P = 0.001). On multivariable analysis, undergoing primarily palliative treatment (OR, 5.2; 95 % confidence interval (CI), 3.2-8.4; P < 0.001), age at LRRC >60 years (OR, 1.9; 95 % CI, 1.3-2.7, P < 0.001), advanced primary tumour stage (OR, 1.5; 95 % CI, 1.1-2.1; P = 0.021), and anastomotic leak at index surgery (OR, 1.8; 95 % CI, 1.2-2.7; P = 0.008) were associated with reduced LRRC 5-year survival. CONCLUSIONS: The current study suggests that features of the primary tumour and technical factors at the time of index proctectomy influence both the location of LRRC and survival.

Risk and location of cancer in patients with preoperative colitis-associated dysplasia undergoing proctocolectomy.

OBJECTIVE: To evaluate the influence of preoperative dysplasia grade, appearance, and site on risk and location of cancer in patients with colitis. BACKGROUND: The ability to predict the presence and location of cancer in colitis patients with dysplasia is essential to facilitate recommendations regarding the necessity and type of surgery. METHODS: Ulcerative and indeterminate colitis patients who underwent proctocolectomy for dysplasia were retrospectively selected. Patient characteristics and findings at colonoscopic surveillance were associated with findings on the surgical specimen by regression analysis. RESULTS: From 1984 to 2007, 348 proctocolectomy specimens with preoperative dysplasia showed cancer in 51 (15%) and dysplasia in 172 (49%) cases. Patients with preoperative high-grade dysplasia (HGD) had cancer in 29% compared with 3% in low-grade dysplasia (LGD) (P < 0.001). Patients with preoperative dysplasia-associated lesion/mass (DALM) had cancer in 25% compared with 8% in flat dysplasia (P < 0.001). In LGD with DALM, the risk of cancer was not significantly higher than in flat LGD (7% vs 2%, P = 0.3), but risk of cancer or HGD was higher with a threefold increase (29% vs 9%, P = 0.015). On multivariate analysis, HGD, DALM, and disease duration were independent risk factors for postoperative cancer. In patients with isolated colonic dysplasia above the sigmoid level, postoperative rectal involvement was limited. CONCLUSIONS: Risk of cancer for patients with HGD or DALM is substantial. Despite low risk of cancer in patients with flat LGD, threshold for surgery should be low given the high prevalence of postoperative pathologic findings. Only in selected cases, colonoscopic surveillance after discussion of associated risks may be acceptable, provided high patient compliance can be assured. Surgery should be considered in all other cases, because it is the only modality that can eliminate the risk of cancer. The location of preoperative dysplasia may allow for the clarification of the need for proctectomy especially in the poor risk surgical patient.

Pneumoperitoneum in the presence of acute and chronic kidney injury: an experimental model in rats.

PURPOSE: There is evidence that pneumoperitoneum induces transient changes in renal function in healthy individuals. Its effect on malfunctioning kidneys is not well known. We investigated effects caused by pneumoperitoneum in animals with impaired renal function. MATERIALS AND METHODS: Male Wistar rats underwent subtotal (5/6) nephrectomy in 2 sequential steps to induce renal failure. Two and 10 weeks postoperatively rats were classified with acute and chronic kidney injury, respectively. At those time points all rats were exposed to 0, 5 and 8 mm Hg pneumoperitoneum for 60 minutes. Changes in creatinine, blood urea nitrogen and creatinine clearance were measured. Histopathological changes and apoptosis were also evaluated in the subgroups. RESULTS: A total of 18 rats with acute and 18 with chronic kidney injury completed the study. Creatinine and blood urea nitrogen did not change after applying pneumoperitoneum in the different pressure subgroups but creatinine clearance significantly decreased in the 5 and 8 mm Hg subgroups in rats with acute and chronic kidney injury. Histopathological findings in the acute kidney injury subgroups that underwent 5 and 8 mm Hg pressure revealed ischemic changes while compensatory hypertrophy was noticed in the chronic injury pressurized subgroups. The apoptotic count was significantly higher in the chronic injury subgroups compared to their acute injury pressurized counterparts. CONCLUSIONS: Pneumoperitoneum seems feasible in rats with impaired baseline renal function. Particularly chronic cases should not be considered a contraindication to pneumoperitoneum while in acute cases pneumoperitoneum might be detrimental.

Frozen section examination may facilitate reconstructive surgery for mid and low rectal cancer.

BACKGROUND: Distal margin >1 cm provides an oncologic safety in low-lying rectal cancers. We evaluated the accuracy of frozen section (FS) examination in estimating distal margins, and its impact on intraoperative decision making regarding restorative proctectomy. METHODS: Retrospective study of patients who underwent surgery for adenocarcinoma of the mid or lower rectum during 2001-2010 and for whom a distal margin specimen was examined intraoperatively by FS, to confirm microscopically free margins. Intraoperative findings, and frozen and final paraffin section findings were retrieved from patient charts. A distal margin of ≤1 cm was compared with >1 cm, for free margins at final pathology and local recurrence (LR). The impact of a distal margin ≤5 mm was also assessed. The impact of FS on intraoperative decision making, in patients who did and did not receive preoperative chemoradiotherapy, was assessed. RESULTS: The mean age of the 63 patients studied was 66.4 ± 11.8 years, and median tumor distance from the anal verge 6 cm (range 1-10 cm). Seven patients underwent abdominoperineal resection, 54 anterior resection, and two Hartman procedures. FS sensitivity and specificity were 83% and 98%, respectively. Accuracy of FS was high for the 41 patients treated with preoperative chemoradiotherapy, and the 22 who were not. Distal margin >5 mm at FS examination ensured a free margin at final pathology. LR rate was comparable between patients with distal margin >10 mm and ≤10 mm, 8% vs 11%, P = 0.65. CONCLUSIONS: FS examination may help determine free distal margin and consequently, in selected cases, may facilitate a restorative procedure in patients with low rectal cancer.

Transanal endoscopic microsurgery for upper rectal tumors.

BACKGROUND: Compared with traditional rectal resection, transanal endoscopic microsurgery (TEM) is faster and safer. This retrospective study sought to assess the efficacy of TEM for lesions located in the upper rectum, ≥10 cm from the anal verge. METHODS: Data from all patients who underwent TEM for rectal lesions ≥10 cm from the anal verge between 2001 and 2010 at two medical centers in Israel were retrospectively analyzed. The study group comprised 96 patients (57 men, 39 women) who underwent 99 TEM procedures. Collected data included patient demographics, tumor characteristics, indications for surgery, operative findings and details, postoperative outcomes, and histopathologic findings. Long-term outcomes including local recurrence (LR) for benign lesions and LR and overall survival (OS) for malignant lesions were calculated. Categorical variables were calculated by frequency tables, and linear variables were represented by averages and standard deviation or median with the spread of variables. Survival and LR analysis was performed by Kaplan-Meier and Cox regression methods. RESULTS: The mean tumor distance from the anal verge was 11.3 ± 2 cm and the median tumor size was 2 cm. Early postoperative outcomes were favorable, and no early postoperative mortality was reported. The postoperative morbidity rate was 10%. For long-term outcomes, in the subgroup with benign lesions, after a median follow-up of 8.7 years, the LR rate was 5.1%. In the group with malignant lesions, LR and OS rates were 6.9 and 87%, respectively. CONCLUSIONS: TEM for upper rectal lesions is feasible and may be safe in selected cases. Low morbidity rate, shorter operative time and length of stay, no mortality events, and favorable long-term outcomes support the use of TEM for the treatment of lesions in the upper rectum.

Transanal endoscopic microsurgery: also for the treatment of retrorectal tumors.

Retrorectal tumors are an uncommon pathological entity. Their clinical importance arises from their occasional malignant nature or malignant transformation. The treatment of choice for most presacral tumors is surgical excision. The approach depends upon the upper limit of the lesion and the presumptive pathology. We reviewed the main features of these tumors with emphasis on transanal endoscopic microsurgery (TEM) as a viable surgical approach for the treatment of the lesions, undertaken in our institution. We present our small case series, consisting of six patients with retrorectal lesions who underwent local excision via TEM. Early and late postoperative outcomes are presented. TEM for retrorectal lesions appears to be a feasible and safe approach. A remarkably low morbidity favors TEM in selected patients.

Oxidants as important determinants of renal apoptosis during pneumoperitoneum: a study in an isolated perfused rat kidney model.

INTRODUCTION: Pneumoperitoneum-associated ischemia-reperfusion (IR) may initiate renal dysfunction. Whether oxidants are responsible for renal structural damage, such as cell apoptosis, has not yet been evaluated. We investigated such eventuality in an isolated rat kidney model. METHODS: Thirty-five rat kidneys with their vessels and ureter were harvested and perfused within a closed environment at flow of 15 ml min(-1). After stabilization, kidneys were assigned to one of five groups (n = 7 per group): CO(2)-induced intrachamber pressure of 8, 12, or 0 mmHg (control), and 8 or 12 mmHg pressure applied to kidneys from rats treated pre-experimentally with tungsten for 14 days. Pressurization lasted 60 min. RESULTS: Organ perfusion pressure raised as intrachamber pressure increased. Urinary output decreased in the two pressurized nonpretreated groups. Intrachamber pressure was directly associated with an increase in postexperimental xanthine oxidase tissue levels. Twofold apoptosis was documented (p < 0.05) in cortex of nonpretreated kidney in the 12 mmHg group compared with the 8 or 0 mmHg groups. Tungsten pretreatment significantly (p < 0.05) attenuated the abnormalities documented in the 12 mmHg group, but less so in the 8 mmHg pressurized nontreated counterparts. CONCLUSIONS: Pneumoperitoneal pressure applied to isolated perfused kidney is associated with renal apoptosis. This rapidly induced structural renal damage is oxidant dependent and can be attenuated by antioxidants. Further studies may shed more light on the role of antioxidants in preventing pneumoperitoneum-induced kidney dysfunction.

Changes in end-tidal carbon dioxide due to gastric perforation during pneumoperitoneum in the rat.

BACKGROUND: Carbon dioxide is the most widely used gas to establish pneumoperitoneum during laparoscopic surgery. Gastrointestinal trauma may occur during the peritoneal insufflation or during the operative phase itself. Early diagnosis of these injuries is critical. OBJECTIVES: To assess changes in end-tidal carbon dioxide (ETCO2) following gastric perforation during pneumoperitoneum in the rat. METHODS: Wistar rats were anesthetized, tracheotomized and mechanically ventilated with fixed minute volume. Each animal underwent a 1 cm abdominal longitudinal incision. A 0.3 x 0.3 cm cross-incision of the stomach was performed in the perforation group but not in the controls (n = 10/group) and the abdomen was closed in both groups. After stabilization, CO2-induced pneumoperitoneum was established at 0, 5, 8 and 12 mmHg for 20 min periods consecutively, each followed by complete pressure relief for 5 min. RESULTS: Ventilatory pressure increased in both groups when pneumoperitoneal pressure 5 mmHg was applied, but more so in the perforated stomach group (P = 0.003). ETCO2 increased in both groups during the experiment, but less so in the perforated group (P = 0.04). It then returned to near baseline values during pressure annulation in all perforated animals but only following the 0 and 5 mmHg periods in the controls. CONCLUSIONS: When subjected to pneumoperitoneum, ETCO2 was lower in rats with a perforated stomach than in those with an intact stomach. An abrupt decrease in ETCO2 during laparoscopy may signal gastric perforation.

Effects of chronic immunosuppression on long-term oncologic outcomes for colorectal cancer patients undergoing surgery.

INTRODUCTION: The effects of chronic immunosuppressive therapy (CIST) on long-term oncologic outcomes for patients who undergo surgery for colorectal cancer are not known. We investigate whether CIST affects these outcomes. METHODS: From a prospective colorectal cancer database, patients undergoing colorectal resection for cancer between 1996 and 2005 and on CIST (steroids and/or cyclosporine, azathioprine, 6-mercaptopurine, FK-506, methotrexate) were identified and compared with a control group matched for age(±5 year), gender, type, and year (±2 year) of operation; American Society of Anesthesiology score; cancer stage; differentiation; vascular invasion; blood transfusion; and postoperative adjuvant therapy. The groups were compared for early and long-term outcomes. Cox models produced hazard ratios and Wald P values to assess associations between survival and the presence of immunosuppressive treatment. RESULTS: Fifty-five (20 female and 35 male) patients were on CIST for inflammatory disease, transplantation, chronic obstructive lung disease, other cancers, and hypopituitarism. Both groups were comparable for the matched characteristics. Chronic immunosuppressive therapy and control groups had similar overall postoperative morbidity (36.4% vs 27.3%, P = 0.3) and wound infection rates (14.5% vs 5.5%, P = 0.13). Chronic immunosuppressive therapy group had significantly lower 3- and 5-year overall (49.1% vs 76.3%, and 45.1% vs 66.2%, respectively, P = 0.003) and disease-free survival (45.5% vs 69.1%, and 41.7% vs 63.3%, respectively, P = 0.005) than the control group. Local recurrence was similar between groups. CONCLUSION: Patients on chronic immunosuppression tolerate colorectal cancer resection but have significantly worse long-term oncologic outcomes.These findings need careful consideration when evaluating the relative roles of the various treatment modalities for this group of patients presenting with colorectal cancer.

Intrasplenic preconditioning: a model for the study of xenostimuli accommodation.

BACKGROUND: Discordant xenotransplantation, the grafting of organs from one phylogenic species to another, results in hyper-acute rejection (HAR). HAR is associated with the deposition of recipient preformed xenoreactive natural antibodies and complement on the endothelium of the donor organ, leading to activation and apoptosis of the endothelium, an event associated with xenograft rejection. Endothelial resistance to HAR, termed "accommodation," an active protection of graft endothelium, may be achieved by previous stimulation of endothelial cells by discordant xenoantibodies. MATERIALS AND METHODS: Forty-eight male Wistar rats were used to evaluate HAR induction in an isolated, dually perfused in-situ rat liver transfused with human blood. This ex-vivo model served to mimic rat-to-human liver xenotransplantation. Preconditioning of the liver endothelium was induced by rat intrasplenic injection of human blood (n=8) or effluent of previously xenotransfused rat liver (n=8), i.e., high versus low xenoantibody solution, each undertaken 1d before liver xenotransfusion. Two other groups were not preconditioned. Preconditioned and non-preconditioned rats were perfused directly with human blood, and eight rats were used as controls (non-preconditioned Krebs-perfused). Eight rats were perfused directly with human blood, and eight rats were used as controls. The effluent that exited these first-line livers was used to perfuse the second-line livers. RESULTS: Portal and hepatic artery perfusion pressures, resistances, rates of oxygen extraction, lactic acid and pH, and wet-to-dry weight ratio values were significantly increased in livers xenotransfused with blood indicating HAR, compared with unchanged values in livers perfused with Krebs solution. Portal pressure and resistance were best protected from HAR by the blood preconditioning in the blood perfused group, while the hepatic artery perfusion system was better protected by the perfusate precondition-blood perfused group. The physiologic effects of HAR were attenuated in most second-line livers. CONCLUSIONS: Attenuation of HAR in rats' livers is achieved by preconditioning with xenoantibodies and/or by "filtering out" xenoantibodies present in the circulation, and is suggestive of accommodation. This novel method may be useful in future studies aimed at refining methods for accommodating xenotransplantation.

Colorectal cancer complicating inflammatory bowel disease: similarities and differences between Crohn's and ulcerative colitis based on three decades of experience.

INTRODUCTION: The aim of this study was to evaluate patient- and tumor-related characteristics for patients undergoing surgery for cancer complicating inflammatory bowel disease (IBD), and to assess differences between patients with Crohn's disease (CD) and ulcerative colitis (UC). METHODS: Data on all IBD patients with colon and rectal cancer (CRC) undergoing surgery between 1980 and 2007 were evaluated from prospectively maintained CRC and IBD databases. Clinical presentation, tumor stage, presence of associated dysplasia, and short- and long-term outcomes after surgery were investigated. Outcomes for IBD patients were compared with a matched group of patients with sporadic cancer. RESULTS: A total of 240 IBD patients (64 CD and 176 UC) with CRC were identified. At the time of CRC diagnosis, 68% UC and 26% CD patients had pancolitis. About 92% of the patients who underwent preoperative colonoscopy were noted to have suspicious lesions. Although 92.5% of the patients had a preoperative histopathologic diagnosis of cancer or dysplasia, incidental diagnosis of cancer in the resection specimen was made in 3%. Examination of the resection specimen revealed synchronous dysplasia in 48% of the patients and synchronous cancer in 12% patients. Tumor location was rectum in 36%, right colon in 28%, sigmoid colon in 17%, transverse colon 10%, and left colon in 9% of patients. CD patients were diagnosed at a more advanced cancer stage than UC. Local recurrence and overall 5-year survival rates were comparable (5.6% vs. 6.7%, P = 0.78 and 77% vs. 72%, P = 0.5, respectively) for patients with IBD and sporadic cancer. CONCLUSIONS: Most IBD cancer can be diagnosed or suspected on the basis of endoscopic findings, biopsy of areas of active colitis, and an incidental finding of malignancy after colorectal resection for other indications is rare. CD patients present with a more advanced cancer stage. Optimal endoscopic surveillance may identify most patients with IBD cancer.

Mannitol attenuates kidney damage induced by xanthine oxidase-associated pancreas ischemia-reperfusion.

BACKGROUND: Ischemia and subsequent reperfusion (IR) may induce local and remote organ reperfusion injury. It may be propagated by xanthine oxidase (XO)-generated oxidant stress. We investigated whether pancreas IR directly and acutely induces renal dysfunction and if this outcome could be prevented by mannitol. MATERIALS AND METHODS: Rat pancreases were isolated and perfused with Krebs-Henseleit solution enriched with 5% bovine albumin. Other rats donated kidneys that were perfused at constant pressure mode. Each pancreas underwent 45 min of either perfusion (control) or ischemia (no flow). Both organ perfusion systems were then combined and the kidneys were perfused with the pancreatic 15-min reperfusate for 2 h. A third group consisted of paired ischemic pancreases and nonischemic kidneys treated with mannitol 250 mg/kg body weight during reperfusion. RESULTS: The controls demonstrated no abnormal perfusion or metabolite changes. Pancreas and renal perfusion pressures increased by >50% in the ischemia group immediately upon reperfusion; it remained above the values of controls during the 2-h kidney reperfusion. Conversely, perfusion pressure in the treatment group was not significantly different from the control. The reduced glutathione level increased significantly, as did XO, immediately upon starting reperfusion in both organs appertaining to the ischemic group; this misbalance was not documented in the controls and the mannitol-treated groups. Urine output was severely reduced in the IR kidneys. CONCLUSION: Ischemia/reperfusion of the rat pancreas evokes immediate renal dysfunction. Kidney oxidant-antioxidant balance is disturbed, but can be prevented with mannitol. These two figures underline the role of oxidative stress in promoting acute renal damage in the presence of pancreas IR.

Is the laparoscopic approach to colectomy safe for the morbidly obese?

BACKGROUND: The feasibility and safety of laparoscopic colectomy (LC) for morbidly obese patients has not been reported previously. This study aimed to assess the clinical outcomes of patients with a body mass index (BMI) of 40 kg/m(3) or more who undergo laparoscopic colorectal surgery. METHODS: Prospectively accrued data for patients with a BMI of 40 kg/m(3) or more (group A) who undergo LC were compared with those for patients with BMI lower than 30 kg/m(3) (group B) matched for year of surgery, indication, operating surgeon, and type of procedure. RESULTS: Each group had 36 patients. The group A patients were significantly younger (54 vs. 61 years; P = 0.04), had higher American Society of Anesthesiology (ASA) scores (P = 0.001), and had diabetes mellitus (P = 0.04). The indications for surgery and the operations performed were similar. The two groups had similar operating times (177.9 vs. 136.4 min; P = 0.12), estimated blood losses (222.3 vs. 157 ml; P = 0.1), median lengths of hospital stay (LOS) (4.5 vs. 4 days; P = 0.2), and returns of bowel function (4.2 vs. 3.9 days; P = 0.45). Group A had significantly longer incisions (6.9 vs. 5 cm; P = 0.02). Conversions (5 vs. 3 patients; P = 0.7), readmissions (12 vs. 6 patients; P = 0.46), reoperations (5 vs. 3 patients; P = 0.17), wound infections (7 vs. 2 patients; P = 0.14), anastomotic leaks (3 vs. 2 patients; P = 0.7), and abdominal abscesses (3 vs. 2 patients; P = 0.7) were more predominant in group A, although the differences did not reach statistical significance. CONCLUSIONS: Laparoscopic colectomy is feasible for morbidly obese patients and results in recovery of intestinal function and LOS equivalent to that for nonobese patients. As expected, morbidity and conversion rates are higher for morbidly obese patients undergoing LC than for nonobese patients.

Prophylactic fluconazole does not improve outcome in patients with purulent and fecal peritonitis due to lower gastrointestinal perforation.

The benefit of anticandida treatment in addition to standard antibiotic therapy in the presence of perforation/leakage of the lower gastrointestinal tract (LGIT) is still controversial. We retrospectively assessed the clinical effects of empiric anticandida treatment in patients with LGIT perforation who had undergone exploratory laparotomy due to perforated/leaking bowel or appendix between 1999 and 2004, including generalized fecal/purulent peritonitis. Two groups of patients emerged: those receiving empiric anticandida treatment (fluconazole, n = 24) and those who did not (n = 77). All the fluconazole-treated and 40/77 nonfluconazole-treated patients required intensive care unit care and were the subject of this assessment. Postoperative candida infection and mortality rates were similar in the critically-ill fluconazole-treated and nontreated patients (4% vs 7%, 21% vs 22.5%, respectively, P = NS); resistant candidiasis rates were also similar. Hospital and intensive care unit stays were longer in the treated group, however not reaching statistical difference (26.5 +/- 18 vs 21.4 +/- 18.3 days, 14.8 +/- 14.2 vs 9.3 +/- 14.1 days, respectively). The rates of morbidity, pneumonia, and multiorgan failure were significantly higher (P < 0.05) in the treated patients (87% vs 63%, 37% vs 7.5%, and 58% vs 35%, respectively). Empiric fluconazole in patients with peritonitis associated with LGIT perforation did not improve patients' outcome compared with those without empiric treatment.

Effects of methylene blue and volatile anesthetics on survival in a murine hemorrhage resuscitation model.

BACKGROUND: Hemorrhage is a frequent cause of morbidity and mortality, possibly complicated by volatile anesthetics administered during surgical emergencies. Because methylene blue (MB) was suggested to reduce bleeding, we reasoned that it may improve resuscitation. We used a rat model of controlled and uncontrolled hemorrhage with fluid resuscitation, aiming at high versus low mean arterial pressure (MAP) to assess the role of early MB injection on survival and the effects of different anesthetics on outcome. METHODS: Wistar male rats (n = 160) were subjected to 15-minute controlled and 60-minute uncontrolled hemorrhage and received lactated Ringer's solution replacement. Four sets (four groups per set, N = 10 per group) were anesthetized with halothane, isoflurane, sevoflurane, or ketamine (KET; control). Resuscitation-targeted MAP was 80 mm Hg in two groups per set and 40 mm Hg in two groups per set: one group received MB 25 mg/kg intravenously and the other one did not receive. RESULTS: All parameters were worse in the higher target groups compared with the lower MAP target groups. MB improved variable outcomes in the treated compared with the nontreated groups, independent of the MAP or anesthesia agent: the amount of replacement volume, lung tissue xanthine oxidase activity, and rats' survival rates. Outcomes with and without MB were worse in the halothane set, followed, in ascending order, by sevoflurane, isoflurane, and KET. CONCLUSIONS: MB improved parameters and survival rates after controlled and uncontrolled hemorrhage and fluid resuscitation, even in high MAP-resuscitated rats. KET seemed to be the best anesthetic choice among the four classic agents tested. The effects of balanced anesthesia and total intravenous anesthesia in similar conditions require additional studies.

Renal oxidative stress following CO2 pneumoperitoneum-like conditions.

BACKGROUND: Physiologic renal changes associated with pneumoperitoneum (PNP) have been described and various underlying mechanisms have been suggested. We investigated the possibility that PNP-associated renal damage is pressure dependent, and that oxidative stress is thereby involved. MATERIALS AND METHODS: Seventy Wistar rat kidneys (n=10 per group) were isolated. They were perfused with oxygenated, warm, Krebs-Henseleit solution containing 5% albumin within an isolated environment and subjected to various CO(2) pressures (0 [control], 3, 5, 8, 12, 15, and 18 mmHg) for 60 min. Half of each group was additionally perfused for 30 min at 0 mmHg pressure. RESULTS: Renal flow decreased proportionately to the applied pressure as did urine output: both decreased (P < 0.05) after 60 and 90 min when pressure >or=8 mmHg was applied. Oxygen extraction decreased (P<0.05) during PNP in all pressurized groups. Xanthine oxidase (XO) activity and reduced glutathione in the tissues increased (P<0.05) proportionately to pressures >or=8 mmHg. All parameters slightly reversed toward baseline values, upon the release of the intra-chamber pressure, except for the 18 mmHg group's values. CONCLUSIONS: CO(2)-PNP pressure induces kidney injury, possibly reversible immediately after pressure is annulled. Pressure is associated with oxidative stress, which interferes with cellular metabolism and function, possibly via an ischemic-reperfusion-like mechanism.