Long term assessment of antibiotic prophylaxis and biliary microbiome in pancreaticoduodenectomy.

INTRODUCTION: Surgical site infections (SSI) can represent a major complication of pancreaticoduodenectomy (PD). We summarize the outcomes of process improvement efforts to reduce the SSI rates in PD that includes replacing Cefazolin with Ceftriaxone-Metronidazole as antibiotic prophylaxis. Additional efforts included current assessment of biliary microbiome and potential prophylactic failures based on bile cultures and suspected antibiotic allergies. METHOD: A single-center review of PD patients from January-2012 to March-2021. Study groups were divided into Pre and Post May-2015 (Group 1 and 2, respectively) when Ceftriaxone-Metronidazole prophylaxis and routine intraoperative cultures were standardized. Univariate and multivariable analyses were conducted to assess groups' differences and association with SSI. RESULTS: Six hundred ninety patients identified [267(38.7%) and 423(61.3%) in Group 1 and Group2, respectively]. After antibiotic change, SSI rates decreased from 28.1% to 16.5% (incisional: 17.6%-7.5%, organ-space or abscess: 17.2%-13.0%), Group 1 and Group 2, respectively, P<0.001. Ceftriaxone-Metronidazole was used in 75.9% of patients Group 2. When adjusting for other covariates, an SSI-decrease was associated only with Ceftriaxone-Metronidazole (OR 0.34, P<0.001). CONCLUSIONS: Ongoing process improvement has resulted in decreased SSIs with Ceftriaxone-Metronidazole prophylaxis. The benefit of Ceftriaxone-Metronidazole is independent of the biliary microbiome. Improving prophylaxis for those with suspected penicillin allergy is warranted.

What is the fate of the cholecystostomy tube following percutaneous cholecystostomy?

INTRODUCTION: Cholecystectomy is the preferred treatment for acute cholecystitis with percutaneous cholecystostomy (PC) considered an alternative therapy in severely debilitated patients. The aim of this study was to evaluate the efficacy and outcomes of PC at a tertiary referral center. METHODS: We retrospectively reviewed all patients that had undergone PC from 2000 to 2014. Data collected included baseline demographics, comorbidities, details of PC placement and management, and post-procedure outcomes. The Charlson comorbidity index (CCI) was calculated for all patients at the time of PC. RESULTS: Four hundred and twenty-four patients underwent PC placement from 2000 to 2014, and a total of 380 patients had long-term data available for review. Within this cohort, 223 (58.7 %) of the patients were male. The mean age at the time of PC placement was 65.3 ± 14.2 years of age, and the mean CCI was 3.2 ± 2.1 for all patients. One hundred and twenty-five (32.9 %) patients went on to have a cholecystectomy following PC placement. Comparison of patients who underwent PC followed by surgical intervention revealed that they were significantly younger (p = 0.0054) and had a lower CCI (p < 0.0001) compared to those who underwent PC alone. CONCLUSIONS: PC placement appears to be a viable, long-term alternative to cholecystectomy for the management of biliary disease in high-risk patients. Old and frail patients benefit the most, and in this cohort PC may be the definitive treatment.

Two randomized, double-blind, placebo-controlled, dose-escalation phase 1 studies evaluating BTH1677, a 1, 3-1,6 beta glucan pathogen associated molecular pattern, in healthy volunteer subjects.

BACKGROUND: BTH1677 is a beta glucan pathogen associated molecular pattern (PAMP) currently being investigated as a novel cancer therapy. Here, the initial safety and pharmacokinetic (PK) results of BTH1677 in healthy subjects are reported. SUBJECTS AND METHODS: In the Phase 1a single-dosing study, subjects were randomized (3:1 per cohort) to a single intravenous (i.v.) infusion of BTH1677 at 0.5, 1, 2, 4, or 6 mg/kg or placebo, respectively. In the Phase 1b multi-dosing study, subjects were randomized (3:1 per cohort) to 7 daily i.v. infusions of BTH1677 at 1, 2, or 4 mg/kg or placebo, respectively. Safety and PK non-compartmental analyses were performed. RESULTS: Thirty-six subjects (N = 24 Phase 1a; N = 12 Phase 1b) were randomized to treatment. No deaths or serious adverse events occurred in either study. Mild or moderate adverse events (AEs) occurred in 67% of BTH1677-treated subjects in both studies. Treatment-related AEs (occurring in ≥10% of subjects) included dyspnea, flushing, headache, nausea, paraesthesia, and rash in Phase 1a and conjunctivitis and headache in Phase 1b. BTH1677 serum concentration was linear with dose. Clearance, serum elimination half-life (t1/2) and volume of distribution (Vss) were BTH1677 dose-independent. In Phase 1b, area under the curve, t1/2, and Vss values were larger at steady state on days 6-30 versus day 0. CONCLUSIONS: BTH1677 was well tolerated after single doses up to 6 mg/kg and after 7 daily doses up to 4 mg/kg.

Dexamethasone, light anaesthesia, and tight glucose control (DeLiT) randomized controlled trial.

BACKGROUND: The inflammatory response to surgical tissue injury is associated with perioperative morbidity and mortality. We tested the primary hypotheses that major perioperative morbidity is reduced by three potential anti-inflammatory interventions: (i) low-dose dexamethasone, (ii) intensive intraoperative glucose control, and (iii) lighter anaesthesia. METHODS: We enrolled patients having major non-cardiac surgery who were ≥40 yr old and had an ASA physical status ≤IV. In a three-way factorial design, patients were randomized to perioperative i.v. dexamethasone (a total of 14 mg tapered over 3 days) vs placebo, intensive vs conventional glucose control 80-110 vs 180-200 mg dl(-1), and lighter vs deeper anaesthesia (bispectral index target of 55 vs 35). The primary outcome was a collapsed composite of 15 major complications and 30 day mortality. Plasma high-sensitivity (hs) C-reactive protein (CRP) concentration was measured before operation and on the first and second postoperative days. RESULTS: The overall incidence of the primary outcome was about 20%. The trial was stopped after the second interim analysis with 381 patients, at which all three interventions crossed the futility boundary for the primary outcome. No three-way (P=0.70) or two-way (all P>0.52) interactions among the interventions were found. There was a significantly smaller increase in hsCRP in patients given dexamethasone than placebo [maximum 108 (64) vs 155 (69) mg litre(-1), P<0.001], but none of the other two interventions differentially influenced the hsCRP response to surgery. CONCLUSIONS: Among our three interventions, dexamethasone alone reduced inflammation. However, no intervention reduced the risk of major morbidity or 1 yr mortality. TRIAL REGISTRATION IDENTIFIER: NCT00433251 at www.clinicaltrials.gov.

Improved quality of life following total pancreatectomy and auto-islet transplantation for chronic pancreatitis.

BACKGROUND: Total pancreatectomy (TP) with auto-islet transplant (AIT) is an extreme treatment for chronic pancreatitis, and we reviewed our experience to assess the impact on quality of life (QOL). METHODS: A prospective cohort study from 2007 through 2010 with pre- and postoperative assessments of the Depression Anxiety Stress Scale, Pain Disability Index, and visual analogue pain scale was performed. RESULTS: Twenty patients underwent TP-AIT with a median follow-up of 12 months (6.75-24 months). All patients reported moderate (45 %) to severe (55 %) pain prior to surgery. TP-AIT resulted in significant decreases in abdominal pain (p < 0.001), 80 % reporting no or mild pain. Despite pain improvement, only 30 % discontinued narcotics. Improvements in all PDI QOL domains improved from 79 to 90 % (p = 0.002), with greatest improvements seen in those without prior pancreatic surgery, younger patients, and in those with higher levels of preoperative pain. Patients were less affected by depression and anxiety prior to surgery, but 60 and 70 % did show improvement in depression and anxiety, respectively (p = 0.033). Sixteen patients (80 %) required exogenous insulin at last follow-up (mean total dose of insulin 11.6 U/day). CONCLUSIONS: TP-AIT significantly improves pain and QOL measures in appropriately selected patients with CP.

Laparoscopic robotic-assisted pancreaticoduodenectomy: a case-matched comparison with open resection.

BACKGROUND: Minimally invasive procedures have expanded recently to include pancreaticoduodenectomy (PD), but the efficacy of a laparoscopic robotic-assisted approach has not been demonstrated. A case-matched comparison was undertaken to study outcomes between laparoscopic robotic approach (LRPD) and the conventional open counterpart (OPD). METHODS: From March 2009 through December 2010, 30 LRPD were performed by two pancreaticobiliary surgeons at the Cleveland Clinic. Thirty OPD patients operated by four pancreaticobiliary surgeons during this same period were matched by demographics, and postoperative outcomes were compared from review of a prospectively collected database. RESULTS: Mean age was 62 years for LRPD versus 61 years for OPD (p = 0.43). Mean body mass index was 24.8 versus 25.6 kg/m(2) (p = 0.49). Surgical indications included adenocarcinoma in 14 patients from each group (46%), intraductal papillary mucinous neoplasm in 4 (14%), and other in 12 (40%). There was one preoperative death in the LRPD group and none following OPD. Morbidity occurred in nine patients (30%) following LRPD versus 13 (44%) in the OPD group (p = 0.14). Intraoperative factors assessed included blood loss (485.8 vs 775 ml, p = 0.13) and operative time (476.2 vs 366.4 min, p = 0.0005). Conversion from LRPD to open occurred in three patients (12%) due to bleeding. Reoperation was performed in two patients (6%) following LRPD versus seven (24%) following OPD (p = 0.17). Length of hospital stay was 9.79 days for LRPD versus 13.26 days in the OPD group (p = 0.043). CONCLUSIONS: This is the first comparison of a novel laparoscopic robotic-assisted PD with the open PD in a case-matched fashion. Our data demonstrate a significant increase in operative time but decreased length of stay for LRPD. The favorable morbidity following LRPD makes it a reasonable surgical approach for selected patients requiring PD.

The quality of information on three common ENT procedures on the Internet.

BACKGROUND: The Internet hosts a large number of high-quality medical resources and poses seemingly endless opportunities to inform, teach, and connect professionals and patients alike. However, it is difficult for the lay person to distinguish accurate from inaccurate information. AIM: This study was undertaken in an attempt to assess the quality of information on otolaryngology available on the Internet. METHODS: Sixty appropriate websites, using search engines Yahoo and Google, were evaluated for completeness and accuracy using three commonly performed ENT operations: tonsillectomy (T), septoplasty (S), and myringoplasty (M). RESULTS: A total of 60 websites were evaluated (NT = 20, NM = 20, NS = 20). A total of 86.7% targeted lay population and 13.3% targeted the medical professionals. 35% of the sites included all critical information that patients should know prior to undergoing surgery and over 94% of these were found to contain no inaccuracies. Negative bias towards medical profession was detected in 3% of websites. CONCLUSIONS: In the current climate, with informed consent being of profound importance, the Internet represents a useful tool for both patients and surgeons.

Comparison of laparoscopic versus open liver tumor resection: a case-controlled study.

BACKGROUND: Although there are data in the literature about the safety and efficacy of laparoscopic liver resections, there are not many studies comparing laparoscopic versus open approaches in a case-matched design. The purpose of this study is to compare the perioperative outcome of laparoscopic versus open liver resections from a single institution. METHODS: Thirty-one patients underwent laparoscopic liver resection between April 1997 and August 2007, with a prospective laparoscopic program started in April 2006 (n=25). This group of patients was compared with 43 consecutive patients undergoing open resection who were matched by size of the lesion (5 cm or less for malignant and 8 cm or less for benign), anatomical location (segments 2, 3, 4b, 5, 6), and type of resection (wedge resection, segmentectomy, partial liver resection). Data were obtained from medical records as well as from a prospective database. Statistical analysis was performed using t-test and chi-square. All data are expressed as mean +/- standard error on the mean (SEM). RESULTS: Mean age in the laparoscopic group was 57.6+/-2.7 years versus 61.9+/-2.3 years in the open group (p=0.2). There were more women in the laparoscopic group [74% females (n=23) and 26% males (n=8)] versus in the open group [40% females (n=17) and 60% males (n=26)] (p=0.003). There were more patients with malignant lesions in the open group (73%) versus in the laparoscopic group (45%) (p=0.01). Eight patients underwent partial and 23 patients segmental/wedge liver resection in the laparoscopic group versus 15 patients who underwent partial and 28 patients segmental/wedge liver resection in the open group (p=0.7). Mean tumor size was 3.9+/-0.4 cm in the laparoscopic group versus 4.2+/-0.3 cm in the open group (p=0.5). Ten (32%) out of 31 cases in the laparoscopic group were hand-assisted. Inflow occlusion was used in 1 case (3%) in the laparoscopic group versus 16 (37.2%) in the open group. Mean operating time was 201+/-15 min for the laparoscopic group and 172+/-12 min for the open group (p=0.1). Mean estimated blood loss during the procedure was 122.5+/-45.4 cc for the laparoscopic group and 299.6+/-33.6 cc for the open group (p=0.002). Surgical margin was similar for malignant cases in both groups. Mean hospital stay was 3.2+/-1.0 days for the laparoscopic group and 6.8+/-0.7 days for the open group (p=0.004). The incidence of postoperative complications was 13% (n=4) in the laparoscopic and 16% (n=7) in the open group (p=0.7). CONCLUSION: This study shows that, with a longer operative time, the laparoscopic approach, despite the learning curve, offers advantages regarding operative blood loss, postoperative analgesic requirement, time to regular diet, hospital stay, and overall cost compared with the open approach for minor liver resections.

Day of surgery admission--is this safe practise?

Day of surgery admission (DOSA) describes the process whereby patients are admitted to hospital and have surgery, on the same day. This is the current admission policy in our institution, for most elective Otolaryngology Head and Neck Surgery patients. We audited 75 consecutive patients admitted on the same day as surgery within our department between May 2006 and January 2007. Significant comorbidity was seen in 28 patients (37.3%). Preoperative investigations prior to surgery were conducted in 64 patients (85.3%). About 21 patients (28%) were delayed going to theatre and the average length of delay was 51 mins. Our cancellation rate was 5.3%. Hospital management have embraced the concept of DOSA in our institution without evaluating the risk to patients. If the DOSA policy is to continue it is imperative that an adequate preoperative assessment clinic is established to prevent negative outcomes for our patients.

Conservative management of vestibular schwannomas: third review of a 10-year prospective study.

Seventy-two patients with a unilateral vestibular schwannoma have been treated conservatively for a median of 121 months. They have been followed prospectively by serial clinical examination, MRI scans and audiometry. Twenty-five patients (35%, 95% CI: 24-47) failed conservative management and required active intervention during the study. No factors predictive of tumour growth or failure of conservative management could be identified. Seventy-five per cent of failures occurred in the first half of the 10-year study. The median growth rate for all tumours at 10 years was 1 mm/year (range -0.53-7.84). Cerebellopontine angle tumours grew faster (1.4 mm/year) than intracanalicular tumours (0 mm/year, P < 0.01); 92% had growth rates under 2 mm/year. Hearing deteriorated substantially even in tumours that did not grow, but did so faster in tumours that grew significantly (mean deterioration in pure tone average at 0.5, 1, 2 and 3 kHz was 36 dB; speech discrimination scores deteriorated by 40%). Patients who failed conservative management had clinical outcomes that were not different from those who underwent primary treatment without a period of conservative management.

Distribution of interstitial cells of Cajal and nitrergic neurons in normal and diabetic human appendix.

The objective of this study was to determine the distribution of enteric nerves and interstitial cells of Cajal (ICC) in the normal human appendix and in type 1 diabetes. Appendixes were collected from patients with type 1 diabetes and from non-diabetic controls. Volumes of nerves and ICC were determined using 3-D reconstruction and neuronal nitric oxide synthase (nNOS) expressing neurons were counted. Enteric ganglia were found in the myenteric plexus region and within the longitudinal muscle. ICC were found throughout the muscle layers. In diabetes, c-Kit positive ICC volumes were significantly reduced as were nNOS expressing neurons. In conclusion, we describe the distribution of ICC and enteric nerves in health and in diabetes. The data also suggest that the human appendix, a readily available source of human tissue, may be useful model for the study of motility disorders.

Induction of nasal hyper-responsiveness by allergen challenge in allergic rhinitis: the role of afferent and efferent nerves.

BACKGROUND: Hyper-responsiveness of nasal secretory function and volume changes are features of allergic rhinitis (AR) that are mediated in part by neural mechanisms. The finding of nasal hyper-responsiveness in subjects with AR who are currently symptomatic, but not in those who are currently out of season and asymptomatic, suggests that induction of neural reflexes in allergic subjects occurs as a result of allergic inflammation. OBJECTIVES: To investigate whether allergen exposure in subjects with asymptomatic seasonal allergic rhinitis (SAR) may lead to induction of neural reflexes, and to investigate the components of the reflexes involved in this induction. METHODS: Asymptomatic subjects with (out-of-season) SAR underwent a nasal bradykinin challenge, before and 24 h after preceding ipsilateral (n = 11) and contralateral (n = 11) antigen challenge. Challenges were performed and nasal secretions collected using filter paper disks, and changes in nasal minimal cross-sectional area (A(min)) were measured using acoustic rhinometry. RESULTS: Preceding ipsilateral antigen challenge led to the induction of a contralateral secretory reflex (P = 0.01), which was absent in control experiments (P = 0.34). Ipsilateral secretion weights were also enhanced. Preceding contralateral antigen challenge also induced a contralateral secretory reflex (P = 0.03). Enhancement of the reduction in contralateral A(min) was also seen (P = 0.02). Ipsilateral responses were unchanged. CONCLUSIONS: Allergen exposure in asymptomatic allergic subjects leads to induction of neural reflexes, resulting in nasal hyper-responsiveness, which persists beyond the resolution of the acute allergic response. Our data suggest that the mechanisms of allergen-induced hyper-responsiveness involve both afferent and efferent components.

Conservative management of vestibular schwannomas - second review of a prospective longitudinal study.

Vestibular schwannomas have been traditionally managed with microsurgical removal and in recent years, stereotactic radiotherapy. However, there is a group of patients in whom a conservative management approach might represent a desirable alternative. The aim of this study was to determine the natural history and outcome following the conservative management of 72 patients with unilateral vestibular schwannomas. This is a prospective cohort review of a previously published group of patients [Clin. Otolaryngol. (2000) 25, 28-39] with unilateral vestibular schwannoma that were initially analysed at our institution in 1998 [Walsh R.M., Bath A.P., Bance M.L. et al., Clin. Otolaryngol. (2000) 25, 28]. The mean duration of follow-up was 80 months (range 52-242 months). All the patients in the study underwent serial magnetic resonance imaging (MRI) for assessment of tumour growth. Patients were deemed to have failed conservative management if there was evidence of rapid radiological tumour growth and/or increasing signs and symptoms, which necessitated active intervention. The mean tumour growth rate for the entire group at the second review was 1 mm/year (range -0.84-9.65 mm/year). The mean growth rate for cerebellopontine angle tumours (1.3 mm/year) was significantly greater than that of internal auditory canal (IAC) tumours (0 mm/year) (P = 0.005). The majority of tumours (87.14%) grew <2 mm/year. There was significant tumour growth seen in 38.9%, no or insignificant growth in 41.7%, and negative growth in 19.4%. Twenty-three patients (32%) failed conservative management at the second review. There was no difference in the outcome of these failed patients in comparison with patients who underwent primary treatment without a period of conservative management. The mean growth rate of tumours in patients that failed conservative management (3.1 mm/year) was significantly greater than that in patients who did not fail (0.2 mm/year) (P < 0.001). No factors predictive of tumour growth or failure of conservative management were identified. Hearing deterioration with pure tone averages (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred irrespective of tumour growth. This prospective study further emphasizes the role of conservative management in selected cases of vestibular schwannomas. Tumours in this study confined to the IAC typically demonstrated minimal or no growth on serial MRI scanning. Regular follow-up with interval scanning is mandatory in all patients.

Laparoscopic splenectomy for lymphoproliferative disease.

BACKGROUND: Elective laparoscopic splenectomy (LS) achieves excellent results for benign hematologic diseases. The role of LS for hematologic malignancies is harder to define owing to associated splenomegaly and patient disease that may alter outcome. METHODS: Retrospective review of single institution experience 1996 through 2002. To limit variability of disease processes, only patients with immune thrombocytopenic purpura (ITP) and lymphoproliferative disease (LPD) were studied. RESULTS: A total of 211 LS have been performed, including 73 for LPD and 86 for ITP. Patients with LPD were significantly older, 61 vs 46 years p<0.001; male, 45 (62%) vs 33 (38%), p<0.001; and larger splenic weight, 680 vs 162 g, p<0.001. Fifty-nine patients (81%) with LPD were operated with standard LS with a conversion rate of 15%. Hand-assisted LS was performed in 14 patients (19%), and three were converted to open. Compared to ITP, patients with LPD had longer operative time, 148 vs 126 min, p<0001, and higher blood loss, 200 vs 100 cc, p = 0.004. There was one mortality (0.6%), and morbidity occurred in six patients (8%) with LPD and seven (8%) with ITP. The median length of stay was 3 days for LPD and 2 days for ITP, p = 0.03. Forty-six patients were principally operated for a diagnosis, and 27 (60%) were found to have lymphoma. CONCLUSIONS: LS can be performed safely in patients with LPD, and when used judiciously with hand-assisted techniques can be performed with low conversion and morbidity rates. Splenectomy plays an important role in establishing the diagnosis of lymphoma in LPD.

Imaging for the diagnosis and staging of periampullary carcinomas.

Multiple imaging modalities are available for investigating patients with a suspected periampullary neoplasm. The relative utility of each imaging modality is discussed regarding its role in diagnosis and staging. A general imaging approach to patients with a distal biliary obstruction also is presented.

Determination of intact splenic weight based on morcellated weight.

BACKGROUND: Comparisons of splenic size based on splenic weight are difficult after laparoscopic splenectomy, which results in a morcellated specimen. We report the results of a direct comparison between morcellated and intact splenic weights. METHODS: Porcine spleens were harvested via a midline laparotomy, and an intact splenic weight was obtained, which served as the control. The spleen then was placed into an impermeable retrieval bag and returned to the peritoneal cavity. A separate 10-mm incision was made and the spleen mechanically morcellated with a uterine forceps. This design most faithfully recreates the morcellation process during laparoscopic splenectomy in humans. The aggregate weight of the fragments was compared with intact splenic weight. RESULTS: Intact and morcellated weights were obtained from 58 porcine spleens. The mean intact splenic weight was 145 g, and the mean morcellated weight was 78 g. For a given morcellated weight achieved at laparoscopic splenectomy, an estimated intact weight can be determined by the following formula: intact weight (g) = morcellated weight (g) x 1.34 + 45. CONCLUSIONS: On the basis of our calculations, a normal spleen weighing 150 g would have a mean morcellated weight of 78 g, and splenomegaly (intact spleen weighing 250 g or more) would be defined by a morcellated weight exceeding 153 g.

Recurrence after laparoscopic ventral hernia repair.

BACKGROUND: Although the early results of laparoscopic ventral hernia repair have shown a low recurrence rate, there is a paucity of long-term data. This study reviews a single institution's experience with laparoscopic ventral hernia repair (LVHR). METHODS: We carried out a retrospective analysis of all LVHR performed at the Cleveland Clinic Foundation from January 1996 to March 2001. Recurrence rates were determined by physical exam or telephone follow-up. Factors predictive of recurrence were determined using Cox regression. RESULTS: Of 100 ventral hernias completed laparoscopically, 96 were available for long-term follow-up (average, 30 months; range 4-65). There were no deaths and major morbidity occurred in seven patients. Recurrences were identified in 17 patients. Nine recurrences occurred in the 1st postoperative year; however, hernia recurrence continued throughout the period of follow-up. Multivariate analysis showed that a prior failed hernia repair was associated with a more likely chance of another recurrence (65% vs 35%, odds ratio (OR) 3.6; p = 0.05) and that an increased estimated blood loss (106 cc vs 51 cc, OR 1.03; p = 0.005) predicted recurrence. Other variables, including body mass index (BMI) (32 vs 31 kg/m2, p = 0.38), defect size (115 cm2 vs 91 cm2; p = 0.23), size of mesh (468 cm2 vs 334 cm2, p = 0.19), type of mesh (p = 0.62), and mesh fixation (p = 0.99), did not predict recurrence. An additional 14 cases required conversion to an open operation, and seven of these cases (50%) had recurrence on long-term follow-up. CONCLUSION: Although LVHR remains the preferred method of hernia repair at our institution, this study documents a higher recurrence rate than many other short-term series. There results underscore the importance of long-term follow-up in assessing hernia surgery outcome.

Retained gallbladder/cystic duct remnant calculi as a cause of postcholecystectomy pain.

BACKGROUND: Pain following cholecystectomy can pose a diagnostic and therapeutic dilemma. We reviewed our experience with calculi retained in gallbladder and cystic duct remnants that present with recurrent biliary symptoms. METHODS: Over the last 6 years, seven patients were referred to us for the evaluation of recurrent biliary colic or jaundice. There were four men and three women ranging in age from 35 to 70 years. All seven had biliary pain similar to the symptoms that precede cholecystectomy; two of them also had also associated jaundice and one had pancreatitis. The time from cholecystectomy to onset of symptoms ranged from 14 months to 20 years (median, 8.5 Years). Four had undergone laparoscopic cholecystectomy and three had had an open cholecystectomy; none had an operative cholangiogram. RESULTS: Five of seven underwent diagnostic endoscopic retrograde cholangiography (ERC), which revealed obvious filling defects in the cystic duct or gallbladder remnant. The final patient was diagnosed by laparoscopic ultrasound after eight negative radiographic studies. Four patients underwent laparotomy and resection of a retained gallbladder and/or cystic duct. Two patients were treated with extracorporeal shock-wave lithotripsy (ESWL); one of them also required endoscopic biliary holmium laser lithotripsy. One patient underwent successful repeat laparoscopic cholecystectomy. There were no treatment-related complications. At a median follow-up of 11.5 months, all have achieved complete stone clearance and are asymptomatic. CONCLUSION: Retained gallbladder and cystic duct calculi can be a source of recurrent biliary pain, and a heightened suspicion may be required to make the diagnosis. This entity can be prevented by accurate identification of the gallbladder-cystic duct junction at cholecystectomy and by routine use of cholangiography. A variety of therapeutic options can be employed to obtain a successful outcome.

Application of the U and gamma' models in binary sweet taste mixtures.

The U and Gamma' models of sensory interactions, successfully applied in olfaction for several years, are tested here using data from published studies on sweetness. The models are subsequently tested on new data obtained in studies of binary mixtures of four sodium sulfamates. The U model allows for the estimation of a global interaction, whereas the Gamma' model allows for the distinction between that which is due to an intrinsic interaction in the mixture itself and that which may be due to the power function exponents in the mixture. The models give satisfactory predictions for observed phenomena of sweet taste suppression, synergism or pure additivity. Additionally, they appear to be more suitable than other models recently applied in taste, particularly the equiratio model. Application of the models to the sulfamate mixtures, reveals additivity for sodium cyclohexylsulfamate (cyclamate)/potassium cyclohexylsulfamate and sodium cyclohexylsulfamate/sodium exo-2-norbornylsulfamate, respectively; whereas for sodium cyclohexylsulfamate/sodium 3-bromophenylsulfamate, the models revealed a slight hypo addition which is simply due to the dissimilarity values of the power function exponents of the components.