Risk factors and outcomes of conversion in minimally invasive distal pancreatectomy: a systematic review.

PURPOSE: The reported conversion rates for minimally invasive distal pancreatectomy (MIDP) range widely from 2 to 38%. The identification of risk factors for conversion may help surgeons during preoperative planning and patient counseling. Moreover, the impact of conversion on outcomes of MIDP is unknown. METHODS: A systematic review was conducted as part of the 2019 Miami International Evidence-Based Guidelines on Minimally Invasive Pancreas Resection (IG-MIPR). The PubMed, Cochrane, and Embase databases were searched for studies concerning conversion to open surgery in MIDP. RESULTS: Of the 828 studies screened, eight met the eligibility criteria, resulting in a combined dataset including 2592 patients after MIDP. The overall conversion rate was 17.1% (range 13.0-32.7%) with heterogeneity between studies associated with the definition of conversion adopted. Only one study divided conversion into elective and emergency conversion. The main indications for conversion were vascular involvement (23.7%), concern for oncological radicality (21.9%), and bleeding (18.9%). The reported risk factors for conversion included a malignancy as an indication for surgery, the proximity of the tumor to vascular structures in preoperative imaging, higher BMI or visceral fat, and multi-organ resection or extended resection. Contrasting results were seen in terms of blood loss and length of stay in comparing converted MIDP and completed MIDP patients. CONCLUSION: The identified risk factors for conversion from this study can be used for patient selection and counseling. Surgeon experience should be considered when contemplating MIDP for a complex patient. Future studies should divide conversion into elective and emergency conversion.

Resection of hepatocellular carcinoma in patients without cirrhosis.

BACKGROUND: Outcomes for patients with hepatocellular carcinoma (HCC) without cirrhosis and factors associated with disease progression remain unclear. The goals of this single-institution study were to define the outcomes for such patients, and to determine factors associated with survival and disease progression. METHODS: This was a retrospective review of consecutive patients with HCC without cirrhosis who underwent hepatic resection between 1985 and 2003. Survival was estimated by the Kaplan-Meier method and risk factors were identified by Cox proportional hazards models. RESULTS: A total of 143 patients were enrolled, of whom 29·4 per cent had identifiable risk factors for chronic liver disease. Major resection (at least three segments) was undertaken in 63·6 per cent of patients. The operative mortality rate was 3·5 per cent. Median disease-free survival was 2·4 years. Multivariable analysis revealed presence of multiple tumours as the only independent predictor of tumour recurrence. Median overall survival was 3·3 years. Factors independently associated with decreased overall survival were multiple tumours, high histological grade, perioperative transfusion, male sex and age at least 66 years. CONCLUSION: Patients with HCC but without cirrhosis have acceptable outcomes after resection. Specific risk factors for the development of HCC in these patients have yet to be defined.

Diabetic and idiopathic gastroparesis is associated with loss of CD206-positive macrophages in the gastric antrum.

BACKGROUND: Animal studies have increasingly highlighted the role of macrophages in the development of delayed gastric emptying. However, their role in the pathophysiology of human gastroparesis is unclear. Our aim was to determine changes in macrophages and other cell types in the gastric antrum muscularis propria of patients with diabetic and idiopathic gastroparesis. METHODS: Full thickness gastric antrum biopsies were obtained from patients enrolled in the Gastroparesis Clinical Research Consortium (11 diabetic, 6 idiopathic) and 5 controls. Immunolabeling and quantitative assessment was done for interstitial cells of Cajal (ICC) (Kit), enteric nerves protein gene product 9.5, neuronal nitric oxide synthase, vasoactive intestinal peptide, substance P, tyrosine hydroxylase), overall immune cells (CD45) and anti-inflammatory macrophages (CD206). Gastric emptying was assessed using nuclear medicine scintigraphy and symptom severity using the Gastroparesis Cardinal Symptom Index. RESULTS: Both diabetic and idiopathic gastroparesis patients showed loss of ICC as compared to controls (Mean [standard error of mean]/hpf: diabetic, 2.28 [0.16]; idiopathic, 2.53 [0.47]; controls, 6.05 [0.62]; P=.004). Overall immune cell population (CD45) was unchanged but there was a loss of anti-inflammatory macrophages (CD206) in circular muscle (diabetic, 3.87 [0.32]; idiopathic, 4.16 [0.52]; controls, 6.59 [1.09]; P=.04) and myenteric plexus (diabetic, 3.83 [0.27]; idiopathic, 3.59 [0.68]; controls, 7.46 [0.51]; P=.004). There was correlation between the number of ICC and CD206-positive cells (r=.55, P=.008). Enteric nerves (PGP9.5) were unchanged: diabetic, 33.64 (3.45); idiopathic, 41.26 (6.40); controls, 46.80 (6.04). CONCLUSION: Loss of antral CD206-positive anti-inflammatory macrophages is a key feature in human gastroparesis and it is associates with ICC loss.

Bariatric surgery at the extremes of age.

The safety and efficacy of bariatric surgery in adolescents and especially in Medicare population have been challenged. Our aim was to determine short-term (30-day) and long-term outcomes of bariatric surgery in patients>or=60 years and or=60 years and 12 patientsor=60 years and all 12 adolescents returned the questionnaire (92%) at a mean of 5 years (range 1-19 years). For patients>or=60 years, 30-day mortality was 0.7%, serious morbidity delaying discharge was 14%, and 5-year mortality was 5%. At a mean of 5 years, body mass index (BMI in kg/m2) decreased from a mean (+/-SEM) of 46+/-1 to 33+/-1 with a 51% resolution of weight-related comorbidities and an 89% subjective overall satisfaction rate. In patients

Mechanism mediating nitric oxide-induced inhibition in human jejunal longitudinal smooth muscle.

BACKGROUND: Enteric neurotransmission is a complex process involving multiple neurotransmitters, including nitric oxide (NO). Our aim was to evaluate the role and mechanism(s) of action of NO in normal human jejunal longitudinal smooth muscle. METHODS: Transmural strips of normal human jejunum obtained from subjects undergoing gastric bypass were studied in organ chambers. Effects of exogenous NO (7 x 10(-6) mol/L to 7 x 10(-5) mol/L) and electrical field stimulation (nonspecific release of endogenous neurotransmitters) on spontaneous contractile activity and on precontracted muscle strips (substance P, 10(-5) mol/L) were evaluated in the presence and absence of the competitive NO synthase inhibitor N(G)-amino-L-arginine (L-NNA, 10(-3) mol/L) and the specific soluble guanylyl cyclase inhibitor 1H-[1,2,4]-oxadiazaolo-[4,3-a]-quinoxalin-1-one (ODQ, 10(-5) mol/L and 10(-4) mol/L). RESULTS: Exogenous NO dose-dependently inhibited spontaneous contractility and relaxed precontracted smooth muscle strips. The effects of NO were markedly attenuated or completely inhibited in the presence of ODQ. Electric field stimulation under nonadrenergic, noncholinergic conditions also inhibited spontaneous contractility and relaxed precontracted smooth muscle strips; both of these effects were attenuated, but not completely inhibited, in the presence of both ODQ and L-NNA. CONCLUSIONS: NO is an endogenous inhibitory neurotransmitter in human jejunal longitudinal smooth muscle, acting at least in part via a mechanism mediated by guanylyl cyclase. Other (non-nitrergic) nonadrenergic, noncholinergic inhibitory neurotransmitters are likely active in this portion of the human gut.

Adrenocortical carcinoma: surgical progress or status quo?

HYPOTHESIS: Outcome of patients with adrenocortical carcinoma (ACC) has improved with the advent of more widely available and higher quality imaging. Operative management strategies and use of adjuvant therapy have not changed. DESIGN: Retrospective review of patient histories, imaging studies, operative data, adjuvant therapy, and outcomes at a single institution. Follow-up was complete for a mean of 53 months. Data was compared with prior institutional experience. SETTING: Tertiary care referral center. PATIENTS: All patients undergoing operative management for ACC during the period from 1980 to 1996. MAIN OUTCOME MEASURES: Determinants of recurrence, survival, and the effect of adjuvant therapy on overall outcome. RESULTS: Fifty-eight patients (30 men, 28 women) with a mean age of 53 years underwent primary operative management for ACC. Functional tumors were identified in 27 patients (47%). Mean tumor size was 12.5 cm. Stage according to the TNM staging system (AJCC Cancer Staging Manual) at presentation was I (n = 0), II (n = 30), III (n = 7), and IV (n = 21). Surgical management included curative resection in 41 (71%), noncurative resection in 14 (24%), and open biopsy in 3 (5%). Perioperative mortality was 5%. Recurrence occurred in 30 patients (73%) with a median time to recurrence of 17 months. Five-year survival by the Kaplan-Meier method was 37%. Prognostic factors (P<.05) included functional status, stage, and chemotherapy in stage III/IV patients. When compared with our prior institutional experience (1960-1980), current patients were more likely to present with stages I to II (52% vs. 34%), have curative resections (71% vs. 50%), and have improved 5-year survival (37% vs. 16%). CONCLUSIONS: (1) Surgical resection remains the principal treatment for stage I to III disease. (2) Adjuvant therapy may improve survival in patients with stage III or IV disease. (3) Current patients were more likely to present at an earlier stage, undergo curative resections, and have improved 5-year survival than institutional historical comparisons.

Contribution of intraoperative enteroscopy in the management of obscure gastrointestinal bleeding.

Obscure gastrointestinal bleeding remains a significant diagnostic challenge. Our aims were (1) to determine the efficacy of intraoperative enteroscopy (IOE) in identifying lesions responsible for obscure gastrointestinal bleeding and (2) to determine the outcome of patients after treatment of these lesions. We retrospectively reviewed all patients who underwent IOE for obscure gastrointestinal bleeding from 1992 to 1998. Patients were divided into those with overt and those with occult gastrointestinal bleeding. Follow-up was complete in 67 patients (96%), with a median of 32 months (range 1 to 91 months). Seventy patients (52 overt and 18 occult) underwent IOE after extensive preoperative evaluation. Median duration of bleeding was 12 months, requiring a median of 14 blood transfusions. Risk factors for bleeding were identified in 46 patients (61%). A lesion was identified and treated in 52 patients (74%)-39 in the overt group and 13 in the occult group. Lesions identified were vascular (54%), ulcerations (31%), tumors (11%), and small bowel diverticula (4%). Overall, 35 patients (52%) were found to have one or more lesions at IOE that were treated surgically and had no further bleeding. IOE, through a mid-small bowel enterotomy, has low morbidity and is effective in that it identified a treatable lesion in 74% of patients, which led to cure of bleeding in 52%.

Ileal absorptive adaptation to jejunal resection and extrinsic denervation: implications for living-related small bowel transplantation.

Net absorption of water, electrolytes, and simple nutrients decreases early after jejunoileal autotransplantation (extrinsic denervation) in a canine model but recovers toward normal by 8 weeks. However, the ability of the extrinsically denervated ileum to adapt after total jejunectomy, which would be relevant as a model of segmental small bowel transplantation, remains unknown. Two groups of five dogs each were studied before and 2 weeks and 12 weeks after 50% proximal enterectomy. A control group remained neurally intact, whereas the other group underwent extrinsic denervation (Ext Den) of the remaining ileum. Using a perfusion technique, net absorption of water, electrolytes, and five simple nutrients (glucose, arginine, glutamine, and oleic and taurocholic acids) was measured at the three time points. Ileal morphometry was also evaluated. All dogs developed diarrhea, which resolved by 12 weeks in all but two of the Ext Den dogs. Weight in both groups was decreased at 2 weeks (P <0.05), returned to normal at 12 weeks in control dogs, but remained low in Ext Den dogs (P <0.05). Maximal weight loss was greater in the Ext Den group (P <0.05). No consistent or important differences in net absorptive fluxes of water, electrolytes, or simple nutrients were noted either within or between groups at any time point. Villous height, crypt depth, and longitudinal muscle width increased significantly at 12 weeks after jejunectomy in the Ext Den dogs, but not in the control dogs (P <0.05). Extrinsic denervation of the ileum results in persistent weight loss after proximal 50% enterectomy. Despite diarrhea, only minor changes in electrolyte absorption occur, and ileal net absorption of simple nutrients remains unaffected. The ileum of extrinsically denervated dogs undergoes a more prominent morphometric adaptation after jejunectomy. Extrinsic denervation necessitated by small bowel transplantation, independent of immune effects, does not appear to suppress the ileal adaptive response to maintain net absorption of water, electrolytes, and simple nutrients.

Duodenal carcinoid tumors: how aggressive should we be?

Duodenal carcinoid tumors are uncommon. It is not known whether they behave more like carcinoid tumors in the appendix (indolent course) or those in the ileum (often virulent)-crucial information for determining the need for radical resection. A retrospective review at our tertiary referral center (from 1976 to 1999) identified 27 patients with primary duodenal carcinoid lesions, excluding functional islet cell tumors. Endoscopic biopsy provided the diagnosis in 78% of patients. Treatment was by endoscopic excision (n = 11), transduodenal excision (n = 8), pancreaticoduodenectomy (n = 3), segmental distal duodenectomy (n = 2), or palliative operation (n = 2). One patient did not undergo operation because of comorbidity. Eighteen of 19 patients with tumors smaller than 2 cm remained disease free after local (endoscopic or transduodenal) excision. The exception was a patient with a small periampullary carcinoid lesion. In contrast, all four patients with carcinoid tumors 2 cm or larger who were resected for cure developed a recurrence (2 to 9 years postoperatively). We conclude that duodenal carcinoid tumors smaller than 2 cm may be excised locally; to ensure complete resection we recommend open transduodenal excision for tumors between 1 and 2 cm. Endoscopic follow-up is indicated. It is unclear whether patients with larger tumors benefit from more aggressive locoregional resection. Ampullary/periampullary carcinoid tumors should be considered separately, as their behavior is unpredictable.

Cystic neoplasms of the pancreas: benign to malignant epithelial neoplasms.

Clinical presentation and state-of-the-art imaging permit the differentiation of most cystic pancreatic neoplasms not only from other cystic pancreatic disorders but also from one another. The differentiation of serous cystic lesions from the mucinous neoplasms (cystadenoma or carcinoma and IPMT) is crucial because of the radically different biological characteristics of these two neoplasms. Although mucinous cystic neoplasms should be resected because of their premalignant or overtly malignant tendency, most patients with serous neoplasms require no operative intervention unless they are symptomatic. IPMT is best treated by a total pancreatectomy, although lesser subtotal resections should be strongly considered depending on patient age, medical comorbidity, and psychosocial situations.

Pathologic features and expression of insulin-like growth factor-2 in adrenocortical neoplasms.

We analyzed a series of adrenocortical neoplasms to compare the clinicopathologic features and the expression of insulin-like growth factor-2 (IGF-2) in adrenocortical adenomas and carcinomas. IGF-2 is a growth factor commonly expressed in many tumors including adrenal cortical and medullary neoplasms. Formalin-fixed paraffin-embedded tissues from 64 adrenocortical adenomas and 67 adrenocortical carcinomas were analyzed. The carcinomas were histologically graded from 1 to 4 based on mitotic activity and necrosis. Tumor weight, size, and follow-up information were obtained by chart review. Expression of IGF-2 was detected by immunohistochemistry with the avidin-biotin-peroxidase complex method and a monoclonal antibody against IGF-2. Adrenocortical carcinomas were larger (mean: 13.1 cm, 787 g) than adenomas (mean: 4.2 cm, 52 g) (p < 0.001). Inpatients with adrenocortical carcinomas, high tumor grade (3 or 4) (p = 0.01) was associated with decreased survival. Expression of IGF-2 was higher in adrenocortical carcinomas than in adenomas (p < 0.001). These results show that tumor size and weight along with expression of IGF-2 protein are useful features to assist in distinguishing between adrenocortical adenomas and carcinomas, and that high tumor grade is a predictor of survival in adrenocortical carcinomas. However, single immunohistochemical markers such as IGF-2 or single histopathologic features cannot by themselves separate adrenocortical adenomas from carcinomas, and a combination of clinical, gross, and microscopic features are needed to establish the diagnosis in difficult cases.

Risk of parathyromatosis after fine-needle aspiration.

Reoperative surgery for hyperparathyroidism (HPT) is fraught with hazard. When preoperative imaging studies are inconclusive or patient comorbidities are extensive fine needle-aspiration (FNA) is helpful to confirm the presence of suspected parathyroid tissue in the neck. Some surgeons refrain from using FNA because of the concern of tissue implantation (parathyromatosis). A retrospective review (1984-1996) of all patients diagnosed with HPT undergoing FNA of suspected parathyroid tissue was performed to document whether a correlation exists between FNA of suspected parathyroid tissue and subsequent development of parathyromatosis. Parathyromatosis was considered to have occurred when proven by histology or suspected on the basis of clinical studies. Of 81 patients with HPT undergoing ultrasound-guided FNA to assess abnormalities in the neck 41 patients with confirmed parathyroid tissue were identified. The indications for FNA in these 41 patients were: prior failed cervical exploration (n = 33), prior neck surgery and/or radiation (n = 2), inconclusive noninvasive imaging studies (n = 15), and severe comorbidities (n = 8). Mean follow-up was 5.8 years. No case of FNA-induced parathyromatosis was identified. FNA is useful to confirm the presence of parathyroid tissue in very select patients with hyperparathyroidism. FNA often eliminates the need for other imaging studies, may prevent a needless or likely fruitless re-exploration, and does not cause parathyromatosis.

Association of low numbers of CD206-positive cells with loss of ICC in the gastric body of patients with diabetic gastroparesis.

BACKGROUND: There is increasing evidence for specific cellular changes in the stomach of patients with diabetic (DG) and idiopathic (IG) gastroparesis. The most significant findings are loss of interstitial cells of Cajal (ICC), neuronal abnormalities, and an immune cellular infiltrate. Studies done in diabetic mice have shown a cytoprotective effect of CD206+ M2 macrophages. To quantify overall immune cellular infiltrate, identify macrophage populations, and quantify CD206+ and iNOS+ cells. To investigate associations between cellular phenotypes and ICC. METHODS: Full thickness gastric body biopsies were obtained from non-diabetic controls (C), diabetic controls (DC), DG, and IG patients. Sections were labeled for CD45, CD206, Kit, iNOS, and putative human macrophage markers (HAM56, CD68, and EMR1). Immunoreactive cells were quantified from the circular muscle layer. KEY RESULTS: Significantly fewer ICC were detected in DG and IG tissues, but there were no differences in the numbers of cells immunoreactive for other markers between patient groups. There was a significant correlation between the number of CD206+ cells and ICC in DG and DC patients, but not in C and IG and a significant correlation between iNOS+ cells and ICC in the DC group, but not the other groups. CD68 and HAM56 reliably labeled the same cell populations, but EMR1 labeled other cell types. CONCLUSIONS & INFERENCES: Depletion of ICC and correlation with changes in CD206+ cell numbers in DC and DG patients suggests that in humans, like mice, CD206+ macrophages may play a cytoprotective role in diabetes. These findings may lead to novel therapeutic options, targeting alternatively activated macrophages.

Distribution of TMEM100 in the mouse and human gastrointestinal tract--a novel marker of enteric nerves.

Identification of markers of enteric neurons has contributed substantially to our understanding of the development, normal physiology, and pathology of the gut. Previously identified markers of the enteric nervous system can be used to label all or most neuronal structures or for examining individual cells by labeling just the nucleus or cell body. Most of these markers are excellent but have some limitations. Transmembrane protein 100 (TMEM100) is a gene at locus 17q32 encoding a 134-amino acid protein with two hypothetical transmembrane domains. TMEM100 expression has not been reported in adult mammalian tissues but does appear in the ventral neural tube of embryonic mice and plays a role in signaling pathways associated with development of the enteric nervous system. We showed that TMEM100 messenger RNA is expressed in the gastrointestinal tract and demonstrated that TMEM100 is a membrane-associated protein. Furthermore TMEM100 immunoreactivity was restricted to enteric neurons and vascular tissue in the muscularis propria of all regions of the mouse and human gastrointestinal tract. TMEM100 immunoreactivity colocalized with labeling for the pan-neuronal marker protein gene product 9.5 (PGP9.5) but not with the glial marker S100ß or Kit, a marker of interstitial cells of Cajal. The signaling molecule, bone morphogenetic protein (BMP) 4, was also expressed in enteric neurons of the human colon and co-localized with TMEM100. TMEM100 is also expressed in neuronal cell bodies and fibers in the mouse brain and dorsal root ganglia. We conclude that TMEM100 is a novel, membrane-associated marker for enteric nerves and is as effective as PGP9.5 for identifying neuronal structures in the gastrointestinal tract. The expression of TMEM100 in the enteric nervous system may reflect a role in the development and differentiation of cells through a transforming growth factor ß, BMP or related signaling pathway.

Changes in interstitial cells of cajal with age in the human stomach and colon.

BACKGROUND: Aging produces inevitable changes in the function of most organs including the gastrointestinal tract. Together with enteric nerves and smooth muscle cells, interstitial cells of Cajal (ICC) play a key role in the control of gastrointestinal motility, yet little is known about the effect of aging on ICC. The aim of this study was to determine the effect of aging on ICC number and volume in the human stomach and colon. METHODS: Gastric and colonic tissues from patients aged 25-70 and 36-92 years old, respectively, and with no co-existent motility disorders were immunolabeled with an anti-Kit antibody and ICC were counted in the circular muscle and myenteric regions. Network volumes were measured using 3D reconstructions of confocal stacks. The effects of aging were determined by testing for linear trends using regression analysis. KEY RESULTS: In both stomach and colon, the number of ICC bodies and volume significantly decreased with age at a rate of 13% per decade. ICC size was only affected in the myenteric plexus in the colon. The changes associated with age were not differentially affected by sex or colonic region. CONCLUSIONS & INFERENCES: The number and volume of ICC networks in the normal human stomach and colon decline with age. This decrease in ICC likely reduces the functional capacity of the gastrointestinal motor apparatus, may contribute to changes in gastrointestinal motility with aging and may influence intestinal responses to insults such as disease, operative interventions and medications in older patients. Tissue specimens must be carefully age-matched when studying ICC in disease.

Gastroesophageal reflux disease in obese patients: the role of obesity in management.

Gastroesophageal reflux disease (GERD) is common in obese patients. The implications of obesity in the etiology, management and outcomes in treatment for GERD have become increasingly important due to an epidemic of obesity. The increasing prevalence of patients with both obesity and GERD merits evaluation of the appropriate surgical intervention for GERD and its symptoms. With the additional advantages of weight loss and resolution of weight-related morbidity (including GERD) bariatric procedures should be the procedure of choice in patients with medically complicated obesity. Patients in lower obesity classes with body mass indices (BMI) of 30-35 kg/m2 without other substantive weight-related comorbidity should prompt consideration of both fundoplication and bariatric procedures, tailoring the best approach based on the specific patient and future implications. Patients classified as overweight but not obese (BMI < 30) are likely best treated with fundoplication; however, no randomized trials comparing fundoplication with the current antireflux bariatric procedures exist.

Colorectal cancers of rare histologic types compared with adenocarcinomas.

PURPOSE: To examine clinical characteristics of colorectal cancers of rare histologic types compared with adenocarcinomas. METHODS: Review of a population-based registry with complete ascertainment. RESULTS: There were 7,422 colorectal cancers, 4,900 (66 percent) colonic and 2,522 (34 percent) rectal. Two hundred fifty-five cancers (3 percent) were of nonadenocarcinoma varieties including 75 (33 percent) squamous, 74 (33 percent) malignant carcinoids, 37 (16 percent) transitional cell-like, 25 (11 percent) lymphomas, 9 (4 percent) sarcomas, and 2 (0.9 percent) melanomas. Sixty (1.2 percent) of the colon cancers occurred in the appendix, and proportionately more carcinoids accounted for these tumors. Compared with adenocarcinomas, colonic and rectal carcinoids and colonic lymphomas accounted for a larger proportion of cancers in the younger age groups. The elderly had proportionately fewer colonic carcinoids. Colonic carcinoids, rectal squamous-cell cancers, and rectal transitional cell-like cancers were more common in women. Colonic lymphomas had a worse prognosis than adenocarcinomas. Survival was better with colonic and rectal carcinoids and rectal transitional cell-like cancers than with adenocarcinomas. CONCLUSIONS: Colorectal cancers of histologic varieties other than adenocarcinoma have distinctive epidemiologic and clinical traits.