Single incision laparoscopic cholecystectomy is associated with a higher bile duct injury rate: a review and a word of caution.

OBJECTIVE: To compare the incidence of bile duct injuries during single incision laparoscopic cholecystectomy (SILC) in relation to the accepted historic rate of 0.4% to 0.5% for standard laparoscopic cholecystectomy (SLC). BACKGROUND: Technically, SILC is more challenging than SLC. The role and benefit of SILC in patient care has yet to be defined. Bile duct injuries have been reported in several series of SILC. METHOD: A comprehensive database search of MEDLINE, EMBASE, CINAHL, and PubMed Central was performed to generate all reported cases of SILC to present. The search was limited to reports of 20 or more patients based on current literature of existing SILC learning curves. Data were analyzed using the Student t test and χ analyses where appropriate. RESULTS: A total of 76 candidate studies were identified; 45 studies met inclusion criteria for an aggregate total of 2626 patients. Most SILCs were performed in the absence of acute cholecystitis (90.6%). The aggregate complication rate was 4.2%, and complications were graded according to the Dindo-Clavien Classification System. Nineteen bile duct injuries were identified for a SILC-associated bile duct injury rate of 0.72%. CONCLUSIONS: There seems to be an increase in the rate of bile duct injuries during SILC when compared with historic rates during SLC. Because most SILCs are performed in optimal conditions, such as lack of acute inflammation, we urge caution in applying this technique to inflamed gallbladder pathology. Controlled trials are needed before conclusions are made regarding safety of SILC.

Multi-institutional analysis of pancreatic adenocarcinoma demonstrating the effect of diabetes status on survival after resection.

BACKGROUND: The effect of diabetes on survival after resection pancreatic ductal carcinoma (PDAC) is unclear. The present study was undertaken to determine whether pre-operative diabetes has any predictive value for survival. METHODS: A retrospective review from seven centres was performed. Metabolic factors, tumour characteristics and outcomes of patients undergoing resection for PDAC were collected. Univariate and multivariable analyses were performed to determine factors associated with disease-free (DFS) and overall survival (OS). RESULTS: Of the 509 patients in the present study, 31.2% had diabetes. Scoring systems were devised to predict OS and DFS based on a training set (n= 245) and were subsequently tested on an independent set (n= 264). Pre-operative diabetes (P < 0.001), tumour size >2 cm (P= 0.001), metastatic nodal ratio >0.1 (P < 0.001) and R1 margin (P < 0.001) all correlated with DFS and OS on univariate analysis. Scoring systems were devised based on multivariable analysis of the above factors. Diabetes and the metastatic nodal ratio were the most important factors in each system, earning two points for OS and four points for DFS. These scoring systems significantly correlated with both DFS (P < 0.001) and OS (P < 0.001). CONCLUSION: Pre-operative diabetes status provides useful information that can help to stratify patients in terms of predicted post-operative OS and DFS.

Extended lymphadenectomy in the surgery of pancreatic adenocarcinoma and its relation to quality improvement issues.

Extended lymphadenectomy has been proposed for loco-regional control of pancreatic adenocarcinoma. While retrospective series suggested a benefit, subsequent prospective trials have not shown a survival benefit. Methods to improve loco-regional control of pancreatic body/tail cancer have not been extensively investigated. Lymph node status is an important surrogate of survival but is not a driving factor for adjuvant chemotherapy. Quality improvement in pancreatic cancer surgery is discussed, focusing on the impact of lymph nodes in determining prognosis.

Surgical and endoscopic management of remnant cystic duct lithiasis after cholecystectomy--a case series.

INTRODUCTION: Postcholecystectomy syndrome (PCS) as a result of remnant cystic duct lithiasis (RCDL), or gallstones within the cystic duct after cholecystectomy, can cause persistent or recurrent symptoms after cholecystectomy. STUDY DESIGN: A retrospective descriptive analysis was performed for all patients with RDCL at a single institution between 2001 and 2012. Details of presentation, diagnosis, and surgical and endoscopic treatments, and outcomes were collected and analyzed. RESULTS: Twelve patients with RCDL were identified. The interval between cholecystectomy to RCDL discovery was 34.2 months (range 0.5-168 months). On a standard liver enzyme panel, 75% of patients had derangements in ≥1 indices, with the most common single laboratory test abnormality occurring in gamma-glutamyl transferase (GGT) (80%). Eight operative reports noted that the cystic duct was noticeably dilated at the time of cholecystectomy. Two patients developed a cystic duct leak (Strasberg type A bile duct injury) postoperatively, which was managed nonoperatively. Six cases of RCDL required surgery, and six were managed endoscopically. CONCLUSION: RCDL is a potential cause of postcholecystectomy syndrome, but the true incidence is unknown. Laboratory analysis and imaging are helpful in establishing the diagnosis of RCDL. Endoscopic therapy has a role in the treatment of RCDL, but surgical excision of the remnant cystic duct lithiasis may be required.

Robotic hepatobiliary and pancreatic surgery: lessons learned and predictors for conversion.

BACKGROUND: The use of surgical robots has slowly gained an increasing presence in the realm of hepatobiliary and pancreatic (HPB) surgery. With additional experience, anecdotal evidence has been useful in guiding patient selection for complex robotic procedures. In the following analysis, we reviewed our case series and looked for predictors of conversion in robotic HPB surgery. METHODS: We retrospectively reviewed all patients who underwent robotic HPB procedures by a single surgeon at two institutions during March 2006-June 2012. Patient demographics, operative data, procedure type and conversion information were recorded. Trends were analysed for indications for conversion. A subset analysis of robotic-assisted laparoscopic distal pancreatomy was performed and compared with laparoscopic and open distal pancreatectomy during the same time period by the same surgeon. RESULTS: During this time period, 77 patients underwent robotic hepatobiliary and pancreatic procedures. All procedures were performed by a single surgeon (J.M.) and included 38 males (49%) and 39 females (51%). Median age was 59 and the majority of patients were ASA class III. There were 24 conversions, which decreased in frequency from 2009 (7) to 2011 (3). Reasons for conversion included significant obesity and technical difficulty. Patients with conversions had more intraoperative blood loss (966 vs 176 ml), more frequently received transfusion (29% vs 2%) and were more likely to have postoperative intensive care. Overall length of stay was longer following conversion (8.3 vs 5.6 days). CONCLUSIONS: Robotic-assisted hepatobiliary and pancreatic procedures are often extremely complex, with a significant learning curve. Recognizing factors that prohibit successful completion of a robotic-assisted surgical procedure is key for patient safety. Careful patient selection in the appropriate settings facilitates the maximal benefit of robotic-assisted complex HPB surgery.

Single-incision laparoscopic cholecystectomy: a combined analysis of resident and attending learning curves at a single institution.

Single-incision laparoscopic cholecystectomy (SILC) is a recent technical modification on standard laparoscopic cholecystectomy that has been shown to be safe and feasible. Recent studies suggest that experienced laparoscopic surgeons have a short learning curve to become proficient in SILC. However, little is known about the interaction of the learning curves of residents and attending surgeons at academic programs. We prospectively evaluated various metrics of both attending and resident surgeons as they progressed in their experience with SILC. Patients were placed into cohorts of 25 based on teaching surgeon experience. Data recorded included patient-specific and operative variables along with complications, conversion to standard laparoscopic cholecystectomy, and outcomes. One hundred one patients underwent SILC. Twelve per cent of patients required conversion to standard laparoscopic cholecystectomy. No significant difference was found in operative times compared within the experience-based cohorts (P = 0.21). A reduction in operative time was shown in residents who were proficient in standard laparoscopic cholecystectomy (SLC) along their learning curve. Operative times remained the same for the teaching surgeon regardless of experience of resident surgeon. SILC has a short learning curve for resident surgeons who are proficient in standard laparoscopic surgery. SILC can be effectively taught with few complications and outcomes similar to SLC with preservation of operative efficiency and safety. Further studies are warranted, however, at a national/international level to define the place and use for SILC as well as the incorporation of single-incision techniques into resident curriculum.

Can residents safely and efficiently be taught single incision laparoscopic cholecystectomy?

OBJECTIVE: Single incision laparoscopic cholecystectomy (SILC) has recently emerged as an option for selected patients undergoing gallbladder removal. While SILC appears safe when performed by experienced surgeons under controlled conditions, there are no studies evaluating the SILC learning curve for incorporation into resident education and the effect on OR efficiency. DESIGN, SETTING, AND PARTICIPANTS: Chief residents were taught and evaluated by a single attending surgeon facile with SILC techniques. Residents were transitioned from assistants to primary surgeon during their clinical rotation. Outcomes data were prospectively tabulated compared with data from standard laparoscopic SLC and attending surgeon SILC outcomes. The setting was an academic, tertiary care teaching hospital. Participants were chief residents rotating on hepatobiliary surgery service. Residents previously had demonstrated mastery of basic laparoscopic surgical techniques. RESULTS: Seven chief residents were evaluated with a total of 49 SILCs with a mean of 7 (range 5-12) SILCS/resident. Five conversions to SLC occurred, all within the first 3 SILCs performed by the resident as operative surgeon. Mean blood loss was 30 mL. Median length of stay was <1 day. Average length of operation increased after the first 2 cases, reflecting the transition of the attending surgeon from primary surgeon to assistant role. By the fifth case, operative times returned to the attending surgeon SILC baseline and historical operative times for SLC at our institution. Factors associated with longer-length of surgery were increasing BMI and presence of acute or chronic cholecystitis, choledocholithiasis, and use of intraoperative cholangiogram. Five postoperative complications occurred and were not associated with position along the resident's learning curve. One death occurred due to metastatic laryngeal cancer within 30 days of SILC. CONCLUSIONS: Residents can safely be taught the techniques of SILC with minimal disruption to operating room efficiency. Residents already proficient in the use of standard laparoscopic techniques transition to SILC quickly with a short learning curve and proper instruction.

Effectiveness of a radiofrequency detection system as an adjunct to manual counting protocols for tracking surgical sponges: a prospective trial of 2,285 patients.

BACKGROUND: Despite rigorous manual counting protocols and the classification of retained surgical items (RSIs) as potential "never events," RSIs continue to occur in approximately 1 per 1,000 to 18,000 operations. This study's goals were to evaluate the incorporation of a radiofrequency detection system (RFDS) into existing laparotomy sponge- and Raytec-counting protocols for the detection of RSIs and define associated risk factors. STUDY DESIGN: All patients undergoing surgery at the University of North Carolina Hospitals from September 2009 to August 2010 were enrolled consecutively. The performance of an RFDS-incorporated accounting protocol for detecting RSIs was prospectively evaluated. Several operative metrics were recorded to identify risk factors for miscounts. RESULTS: A total of 2,285 patients were enrolled. One near miss was detected by the RFDS. Thirty-five miscounts occurred, for a rate of 1.53%. The ultimate locations of miscounted items were surgical site (n = 11), within operative suite (n = 10), surgical drapes (n = 2), and emergency protocol deviations (n = 12). Perioperative variables associated with miscounts were higher estimated volume of blood lost, longer operations, higher number of laparotomy sponges used, open surgical approach, "after hours" operations, change of surgical team during operation, weekend or holiday operations, unanticipated changes in operative plan during surgery, and emergency operations. Body mass index was not associated with miscounts. Surveys completed by participating surgical staff suggested high confidence in the RFDS for prevention of RSIs. CONCLUSIONS: The incorporation of the RFDS assisted in the resolution of a near-miss event (1 of 2,285) not detected by manual counting protocols and assisted in the resolution of 35 surgical-sponge miscounts. No known RSIs occurred during the study period. Risk factors for miscounts were identified and can help identify at-risk surgical populations.

Single incision laparoscopic cholecystectomy using a "two-port" technique is safe and feasible: experience in 101 consecutive patients.

Single incision laparoscopic cholecystectomy (SILC) is a new minimally-invasive technique that has recently been developed to address several disease processes of the gallbladder. However, the safety and feasibility of this technique are still being evaluated. Utilizing a "two-port" technique with transabdominal suture retraction and a rigorous adherence to the critical view of safety, we evaluated our experience in a prospectively maintained database and compared this with standard laparoscopic cholecystectomy (SLC) over the same period. SILC was completed successfully in 87 per cent of patients. Operative times were found to be similar between SLC and SILC (75 and 76 minutes, respectively; P = 0.12). Operative blood loss, hospital stay, and short-term complications were not statistically different between SILC and SLC. Cholangiograms, obtained on a selective basis, were performed in 19 per cent of SILCs. No bile duct injuries occurred during SILC or SLC. Although our aggregate number is not enough to accurately assess the rate or safety of bile duct injuries, SILC seems to be safe and feasible when evaluating other metrics and does not seem to interfere with operative efficiency compared with SLC.

Medically managed hypercholesterolemia and insulin-dependent diabetes mellitus preoperatively predicts poor survival after surgery for pancreatic cancer.

INTRODUCTION: Although patients with pancreatic ductal adenocarcinoma (PDAC) frequently require medications to treat pre-existing conditions, the impact of these treatments on outcomes post-resection is unknown. The purpose of this study was to determine the impact of preoperative medications on overall survival after pancreatic resection. METHODS: Multi-institutional data on preoperative medications and outcomes in patients undergoing resection for PDAC were analyzed. Univariate and multivariate analyses were performed to determine which medications were predictive of early mortality. RESULTS: Of the 518 patients resected for PDAC, 13.3% were being treated preoperatively with insulin, 14.8% were on a statin, 1.7% were on steroids, and 7.6% were on thyroxin. On univariate analysis, patients taking preoperative insulin had a higher 90-day mortality rate relative to those not on insulin (13.0% vs. 4.8%, p = 0.024), and those on a statin had a higher 90-day mortality than those who were not (10.8% vs. 4.6%, p = 0.035). Preoperative steroids and thyroxin were not associated with 90-day mortality (p = 0.409 and p = 0.474, respectively). Insulin and statin use was a stronger predictor of 90-day mortality than history of diabetes (p = 0.101), BMI ≥ 30 (p = 0.166), cardiac disease (p = 0.168), pulmonary disease (p = 1.000), or renal dysfunction (p = 1.000). Older patients also had a higher risk of early postoperative death (p = 0.011). On multivariate analysis, only preoperative insulin usage and statin treatment independently predicted early mortality (odds ratio (OR) = 3.043; 95% confidence interval (CI), 1.256-7.372; p = 0.014, and OR = 2.529; 95% CI, 1.048-6.104; p = 0.039, respectively). Based on the beta coefficients, a simple scoring system was devised to predict survival after resection from preoperative medication use. Zero points were assigned to patients who were on neither insulin nor a statin, one point to those who were on one or the other, and two points to those who were on both insulin and a statin. The score correlated with early postoperative survival (90-day mortality rates of 3.4%, 11.5%, and 13.3% for 0, 1, and 2 points, respectively, p = 0.004). Increasing score was also associated with poorer long-term outcomes, with a median overall survival of 19.6, 15.6, and 11.2 months for 0, 1, and 2 points, respectively (p = 0.002, median follow-up 14.4 months). CONCLUSIONS: Patients with PDAC being treated for pre-existing diabetes or hypercholesterolemia with either insulin or statin-based therapy have an increased risk of early postoperative mortality. A simple scoring system based on preoperative medications can be used to predict early and overall survival following resection.

Mixed micelle formation with phosphatidylcholines: the influence of surfactants with different molecule structures.

The number of mixed micellar (MM) drug products being introduced into the commercial pharmaceutical market is very limited although there is need for alternative dosage forms for poorly soluble active drug substances. While known systems are composed of phosphatidylcholine and bile salts, it was the aim of this study to investigate if alternative surfactants are able to form isotropically clear solutions over a broad range of concentrations and at higher ratios of phosphatidylcholine (PC). It was a particular challenge of this work to find a MM system with a unimodal particle size distribution since it is known that surfactants often form vesicles with phospholipids instead of MM. The theoretical approach behind this work was the transfer of the packing parameter concept, which describes the molecular association of one amphiphilic species, to the organisation behaviour of two different amphiphilic species (water-insoluble phospholipid+surfactant leading to MM). Therefore the influence of the surfactant molecular geometry on the ability to form MM with phospholipids was investigated. A homologous series of two different surfactant classes, namely polyglycerol esters and sucrose esters, with a large hydrophilic head region leading to a smaller packing parameter were analysed regarding their ability to form clear MM solutions with PC. For comparison, surfactants with no strictly defined partition between a polar head and a non-polar tail (e.g. Poloxamer 188) were tested. Decaglycerol laurate and especially sucrose laurate (SL) were superior compared to all other tested surfactants with respect to their ability to form clear solutions with hydrogenated PC (hPC) at a higher ratio and over a broad range of concentrations while unsaturated PC showed an inferior performance to form MM. The favourite MM system composed of SL with 0.5 weight fractions of hPC formed about 20 nm sized MM in a concentration range of 1.0-80 mg/mL and showing a unimodal particle size distribution with a PDI value <0.1. The results of the study have shown that the transferred packing parameter concept is applicable to the tested surfactants to describe their ability forming mixed micelles with PC.

Solubilization of poorly water-soluble drugs by mixed micelles based on hydrogenated phosphatidylcholine.

A remarkable part of newly developed active pharmaceutical ingredients is rejected in early phase development and will never find a way to a patient because of poor water solubility which is often paired with poor bioavailability. Considering such arising solubility problems the development of application vehicles like mixed micelles (MM) is a challenging research topic in pharmaceutical technology. While known classical MM systems are composed of phosphatidylcholine and bile salts, it was the aim of this study to investigate if alternatively developed MM systems were superior in solubilization of different hydrophobic drugs. The novel MM were also comprised of phosphatidylcholine and (contrarily to bile salts) different other suitable surfactants forming binary MM. As model water-insoluble drug substances two benzodiazepines, diazepam and tetrazepam, and the steroid estradiol were chosen. In this study the solubilization capacities of newly developed MM were compared to those of classical lecithin/bile salt MM systems and different other surfactant containing systems. The MM system with sucrose laurate and hydrogenated PC (hPC) at a weight fraction of 0.5 was found to be superior in drug solubilization of all investigated drugs compared to the classical lecithin/bile salt mixed micelles. Further, a polysorbate 80 solution, also at 5%, was inferior with regard to solubilize the investigated hydrophobic drugs. The MM sizes of the favorite developed MM system, before and after drug incorporation, were analysed by dynamic light scattering (DLS) to evaluate the influence of the drug incorporation. Here, the particle sizes, before and after drug incorporation, remained constant, indicating a stable formation of the solubilizate. Further the critical micelle concentration (CMC) of MM before and after drug incorporation was analysed by three different determination techniques. Constant CMC-values could be obtained regardless if diazepam was encapsulated within the MM or unloaded MM were analysed.

Cryosurgical changes in the porcine kidney: histologic analysis with thermal history correlation.

Advances in minimally invasive renal cryosurgery have renewed interest in the relative contributions of direct cryothermic and secondary vascular injury-associated ischemic cell injury. Prior studies have evaluated renal cryolesions seven or more days post-ablation and postulated that vascular injury is the primary cell injury mechanism; however, the contributions of direct versus secondary cell injury are not morphologically distinguishable during the healing/repair stage of a cryolesion. While more optimal to evaluate this issue, minimal acute (< or = 3 days) post-ablation histologic data with thermal history correlation exists. This study evaluates three groups of porcine renal cryolesions: Group (1) in vitro non-perfused (n = 5); Group (2) in vivo 2-h post-ablation perfused (n = 5); and Group (3) in vivo 3-day post-ablation perfused (n = 6). The 3.4 mm argon-cooled cryoprobe's thermal history included a 75 degrees C/min cooling rate, -130 degrees C end temperature, 60 degrees C/min thawing rate, and 15-min freeze time. An enthalpy-based mathematical model with a 2-D transient axisymmetric numerical solution with blood flow consideration was used to determine the thermal history within the ice ball. All three groups of cryolesions showed histologically similar central regions of complete cell death (CD) and transition zones of incomplete cell death (TZ). The CD had radii of 1.4, 1.1, and 1.0 cm in the non-perfused, 2-h and 3-day lesions, respectively. Capillary thrombosis was present in the 2-h perfused cryolesions with the addition of TZ arteriolar/venous thrombosis in the 3-day perfused lesions. Thermal modeling revealed the outer CD boundary in all three groups experienced similar thermal histories with an approximately -20 degrees C end temperature and 2 degrees C/min cooling and thawing rates. The presence of similar CD histology and in vitro/in vivo thermal histories in each group suggests that direct cryothermic cell injury, prior to or synchronous with vascular thrombosis, is a primary mediator of cell death in renal cryolesions.

Cryothermic and hyperthermic treatments of human leiomyomata and adjacent myometrium and their implications for laparoscopic surgery.

STUDY OBJECTIVE: To evaluate the effects and feasibility of direct cryothermic and hyperthermic therapy on leiomyomata and adjacent myometrium, and to contribute to evidence-based treatment thresholds based on measurements of direct cell injury. DESIGN: Experimental study (Canadian Task Force classification II-2). SETTING: University hospital. SUBJECTS: Leiomyoma and myometrium tissue from 10 women undergoing total abdominal hysterectomy with or without bilateral salpingo-oophorectomy. INTERVENTION: In vitro cryothermic or hyperthermic therapy was performed with representative leiomyoma and myometrium tissue samples. Using a directional solidification stage to simulate cryothermic therapy, 10 leiomyoma and 6 myometrium specimens were cooled in vitro at a rate of -5 degrees C/minute to end temperatures of -20 degrees, -40 degrees, -60 degrees, and -80 degrees C with a 15-minute hold period and then rapidly thawed to 21 degrees C. Hyperthermic therapy was simulated using a preheated 45 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, and 80 degrees C constant temperature copper heating block with a 10-minute treatment period. In conjunction with tissue culturing and control tissues, cell death was assessed with routine histology and viability dyes (ethidium homodimer/Hoechst). MEASUREMENTS AND MAIN RESULTS: In cryothermic results, leiomyomata cell death (LCD) increased from 12% to 27% by histology and 26% to 38% by viability dye assay over the thermal range from -20 degrees to -80 degrees C, respectively. Myometrial cell death (MCD) increased from 10% to 12% and 4% to 20% for the same measurements, respectively. Whereas MCD appeared relatively stable from -40 degrees to -80 degrees C, it was significantly less than LCD over this range (p <0.05). For hyperthermic results, LCD increased from 17% to 88% by histology with progressive temperature increase from 45 degrees to 80 degrees C, respectively. The MCD showed a similar increase from 16% to 91% by histology over this temperature range. Hyperthermic histology and dye assay results were similar for LCD and MCD. CONCLUSIONS: In comparison with myometrium, leiomyomata showed greater direct cryothermic and equal hyperthermic cell injury. Whereas cell death increased up to 70 degrees C and down to -80 degrees C, the interval increases in cell injury diminished with more extreme temperatures. In vivo studies of combined direct and ischemic vascular injury thresholds have yet to be performed, but direct LCD matrixes determined in this study will help provide guidelines for minimally invasive surgical techniques for the treatment of leiomyomata.