Efficacy of percutaneous treatment of biliary tract calculi using the holmium:YAG laser.

BACKGROUND: Few Western studies have focused on percutaneous techniques using percutaneous transhepatic choledochoscopy (PTHC) and holmium:yttrium-aluminum-garnet (YAG) laser to ablate biliary calculi in patients unable or unwilling to undergo endoscopic or surgical removal of the calculi. The authors report the efficacy of the holmium:YAG laser in clearing complex biliary calculi using percutaneous access techniques. METHODS: This study retrospectively reviewed 13 non-Asian patients with complex secondary biliary calculi treated percutaneously using holmium:YAG laser. Percutaneous access was accomplished via left, right, or bilateral hepatic ducts and upsized for passage of a 7-Fr video choledochoscope. Lithotripsy was performed under choledochoscopic vision using a holmium:YAG laser with 200- or 365-microm fibers generating 0.6 to 1.0 joules at 8 to 15 Hz. Patients underwent treatment until stone clearance was confirmed by PTHC. Downsizing and subsequent removal of percutaneous catheters completed the treatment course. RESULTS: Seven men and six women with an average age of 69 years underwent treatment. All the patients had their biliary tract stones cleared successfully. Of the 13 patients, 3 were treated solely as outpatients. The average length of percutaneous access was 108 days. At this writing, one patient still has a catheter in place. The average number of holmium:YAG laser treatments required for stone clearance was 1.6, with no patients requiring more than 3 treatments. Of the 13 patients, 8 underwent a single holmium:YAG laser treatment to clear their calculi. Prior unsuccessful attempts at endoscopic removal of the calculi had been experienced by 7 of the 13 patients. Five patients underwent percutaneous access and subsequent stone removal as their sole therapy for biliary stones. Five patients were cleared of their calculi after percutaneous laser ablation of large stones and percutaneous basket retrieval of the remaining stone fragments. There was one complication of pain requiring admission, and no deaths. CONCLUSIONS: The use of PTHC with holmium:YAG laser ablation is safe and efficacious, but requires prolonged biliary access and often multiple procedures to ensure clearance of all calculi.

Changing attitudes toward endolumenal therapy.

BACKGROUND: As with new laparoscopic techniques, the ability to convince surgeons and gastroenterologists to embrace endolumenal techniques and the additional training required to perform the new procedures will correlate with how rapidly endolumenal therapies are adopted. The authors measured their ability to change attitudes among surgeons, who may or may not perform endoscopy as a part of their practice, toward endolumenal therapies. METHODS: As part of the endoluminal therapy postgraduate course presented at the annual Society of American Gastrointestinal Endoscopic Surgeons (SAGES) meeting in Ft. Lauderdale, Florida 2005, experts presented current literature and data on new endolumenal techniques. The participants, primarily of surgeons, were polled electronically about a number of case scenarios before and after their presentation. Each scenario was relevant to the topic presented and chosen to reflect potentially controversial disease processes with traditional or endolumenal treatment options. The responses were collected in real time and displayed to course participants. RESULTS: A panel of 10 experts presented data on a range of endolumenal therapies including endolumenal treatment for gastroesophageal reflux disease (GERD), endoscopic stenting, endoscopic treatments in bariatric surgery, intraoperative endoscopy, endoscopic mucosal resection (EMR), transanal endoscopic microsurgery (TEM), mucosal ablation for Barrett's esophagus, intralumenal resection, translumenal endoscopic surgery, and how to educate surgeons in new endolumenal techniques. Demographic data showed that 83.6% of the participants performed endoscopy as part of their practice. A comparison with traditional surgical options showed a statistically significant positive attitude change (p < 0.05) toward adoption of most endolumenal techniques after expert presentation. Only EMR and TEM did not show a statistically significant change in the participants' willingness to adopt these techniques. There was no significant change in the attitudes of how best to train surgeons. After presentation of the training options, 76% of the respondents believed that these techniques should be taught in residency. CONCLUSIONS: The education of surgeons in new endolumenal therapeutic techniques can have a significant impact in terms of changing practice attitudes and may accelerate adoption of new endoscopic techniques.

Endoluminal and transluminal surgery: current status and future possibilities.

The field of minimally invasive surgery has seen tremendous growth since the first laparoscopic cholecystectomy was performed in 1987. The key question is not how successful these techniques are currently, but rather where may they lead in the future? New technologies promise to usher in an era of even less invasive procedures. The terms being coined in the literature include "incisionless," "endoluminal," "transluminal," and "natural orifice" transluminal endoscopic surgery. These techniques certainly have the potential to become the next wave of minimally invasive procedures. A recent editorial in Surgical Endoscopy by Macfadyen and Cuschieri highlighted the ongoing developments in endoscopic surgery and stressed the critical importance of surgeons being involved in future applications and permutations of these techniques [1]. There are early signs of such involvement. The work of numerous investigators in the field was presented recently at the 2005 Digestive Disease Week. The American Society for Gastrointestinal Endoscopy and the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), in collaboration with the American College of Surgeons, recently organized a postgraduate course in endoluminal therapy at the spring 2005 meeting held in Hollywood, Florida. The course is being offered again at the 2006 SAGES annual meeting. Similar courses are being offered at other regional and national meetings. This review attempts to highlight some of the available and evolving endoluminal therapies reviewed at that forum, including techniques for the management of gastroesophageal reflux disease, endoscopic mucosal resection, endoluminal bariatric surgery, transanal endoscopic microsurgery, and transgastric endoscopic surgery, as well as new technologies and possible future directions in luminal access surgery.

Laparoscopic management and clinical outcome of emphysematous cholecystitis.

BACKGROUND: As opposed to acute, chronic, and acalculus cholecystitis, emphysematous cholecystitis (EC) is associated with significant morbidity and mortality. Only a few studies have specifically reviewed the operative management and clinical outcome of EC. This study documents the operative management and clinical outcome of EC at the Cleveland Clinic Foundation. METHODS: Between January 1996 and June 1999, 18 consecutive patients underwent cholecystectomy for emphysematous cholecystitis at our institution. All charts were reviewed retrospectively, and patients undergoing concurrent procedures were excluded. Mean values +/- standard deviation (SD) of the mean were calculated for patient demographics, preoperative white blood cell count (WBC), bilirubin, alkaline phosphatase, and length of hospital stay. Operative procedure (laparoscopic, converted, or open), preoperative imaging studies, operative time, ICU stay, morbidity, and mortality were reviewed. RESULTS: Patients presented with a mean age of 53.4 years (range, 18-80) and a male/female ratio of 3.5 (14/4). There were no differences between groups in terms of patient demographics. Mean WBC on admission was 14.2 K/mL (range, 5.4-19.7). Mean alkaline phosphatase and total bilirubin were 115 U/L (range, 45-428) and 1.4 mg/dl (range, 0.5-3.4), respectively. Thirteen patients (72%) were completed laparoscopically, two patients (11%) were converted to an open procedure, and three patients (17%) had open surgery. Overall mean length of hospital stay was 5 days (range, 1-18). Two patients from the open group ultimately died 1 year later due to progression of preexisting illness. One of these patients had congestive heart failure and chronic renal failure; the other had metastatic malignant melanoma. None of the patients died in the immediate perioperative period. There were five complications (27.8%). Two patients presented with bleeding secondary to heparin and coumadin therapy. One developed sepsis, and another developed leakage from the cystic duct stump, necessitating an endoscopic retrograde cholangiopancreatogram (ERCP) with stent decompression. The fifth complication, ileus, required readmission 3 days postoperatively, but the patient responded to conservative management. Complications were evenly distributed between the three groups. There were two complications in the laparoscopic group, two in the open group, and one in the conversion group. All other patients were alive at the time of this publication. CONCLUSIONS: Using current techniques, patients with EC can be managed successfully utilizing laparoscopy. Morbidity and mortality appear to be slightly higher than published reports for acute, chronic, and acalculus cholecystitis. Conversion rates are comparable to patients with acute and chronic cholecystitis who undergo laparoscopic cholecystectomy. Based on these data, laparoscopic cholecystectomy should be considered the first-line treatment for patients with known or suspected EC.

Integrative physiology of splanchnic glutamine and ammonium metabolism.

The substrates for hepatic ureagenesis are equimolar amounts of ammonium and aspartate. The study design mimics conditions in which the liver receives more NH(+)(4) than aspartate precursors (very low-protein diet). Fasted dogs, fitted acutely with transhepatic catheters, were infused with a tracer amount of (15)NH(4)Cl. From arteriovenous differences, the major NH(+)(4) precursor for hepatic ureagenesis was via deamidation of glutamine in the portal drainage system (rather than in the liver), because there was a 1:1 stoichiometry between glutamine disappearance and NH(+)(4) appearance, and the amide (but not the amine) nitrogen of glutamine supplied the (15)N added to the portal venous NH(+)(4) pool. The liver extracted all this NH(+)(4) from glutamine deamidation plus an additional amount in a single pass, suggesting that there was an activator of hepatic ureagenesis. The other major source of nitrogen extracted by the liver was [(14)N]alanine. Because alanine was not produced in the portal venous system, we speculate that it was derived ultimately from proteins in peripheral tissues.

Tracing gluconeogenesis with deuterated water: measurement of low deuterium enrichments on carbons 6 and 2 of glucose.

The contribution of gluconeogenesis to glucose production in vivo can be measured by enriching body water with 0.5% 2H2O and measuring the glucose labeling ratio C6/C2 (Landau et al., J. Clin. Invest. 95, 172-178, 1995). We present further refinements of the measurements of the 2H enrichments on C6 and C2 of glucose. The transfer of 2H from C6 of glucose to hexamethylenetetramine (HMT) and extraction in preparation for gas chromatography-mass spectrometry can be done in a single test tube, without distillation of the intermediate formaldehyde. In addition, extraction of small amounts of HMT is greatly improved by making a HMT-iodine adduct. For C2, glucose is reduced to sorbitol, and 2H on C2 is transferred enzymatically to [U-13C3]pyruvate, forming [U-13C3,2-2H]lactate. The latter is assayed by negative chemical ionization gas chromatography-mass spectrometry of the pentafluorobenzyl derivative. The natural enrichment of the [U-13C3]lactyl ion is only 0.4%, allowing measurements of 2H enrichment down to 0.1%. These techniques were used in dogs infused with 2H2O and in isolated rat livers perfused with buffer containing 1 to 5% 2H2O. Our data reveal a difference in the rate of labeling of C6 and C2 of glucose in vivo. Lastly, in cows infused with [6,6-2H2]glucose, we show that the turnover of glucose can be economically measured by assaying low tracer enrichment (down to 0.1%) via hexamethylenetetramine.

Contributions of liver and kidneys to glycerol production and utilization in the dog.

The classical concept holds that liver and kidneys are the main sinks of glycerol released by adipose tissue. However, rates of glycerol appearance (Ra) exceed the rate of glycerol delivery to liver and kidneys. We measured the hepatic and renal contributions to glycerol production and utilization in anesthetized dogs that were fasted either overnight or for 24 h after 3 days on a carbohydrate-free diet. Dogs were infused with [2H5]glycerol, and the concentration and 2H enrichment of glycerol were measured across liver and kidney. After a baseline period, either norepinephrine or glucose plus insulin was infused to alter the rate of glycerol production. Our study shows that the production of glycerol by liver and kidneys amounted to 4-9% and 4-7% of the Ra of glycerol, respectively. Uptake of glycerol by liver and kidneys amounted to 26-30 and 10-19% of the Ra of glycerol, respectively. Thus, contrary to the classical concept, the bulk of glycerol utilization occurs in nonhepatic, nonrenal tissues that have very low glycerol kinase activity per gram.

Assay of the deuterium enrichment of water via acetylene.

A technique is presented for measuring the 2H enrichment of water in biological samples when this enrichment is greater than 0.2%. The sample is reacted with calcium carbide to form acetylene gas, which is determined by gas chromatography electron impact ionization mass spectrometry. Ion-molecule reactions, resulting in proton abstraction, are minimized by lowering the electron ionization energy from the usual 70 eV to 45 eV. This technique is much more rapid and economical than the classical isotope ratio mass spectrometric assay of the enrichment of hydrogen gas derived from reduction of water.

Noninvasive probing of citric acid cycle intermediates in primate liver with phenylacetylglutamine.

In human and primate liver, phenylacetate and glutamine form phenylacetylglutamine, which is excreted in urine. Probing noninvasively the labeling pattern of liver citric acid cycle intermediates with phenylacetylglutamine assumes that the labeling pattern of its glutamine moiety reflects that of liver alpha-ketoglutarate. To validate this probe, we infused monkeys with [U-13C3]lactate, [3-13C]lactate, [1, 2-13C2]acetate, [2-13C]acetate, [U-13C3]glycerol, or 2-[3-13C]ketoisocaproate and compared the labeling patterns of urinary phenylacetyl-glutamine with those of glutamate and glutamine in liver, plasma, muscle, and kidney and liver alpha-ketoglutarate. Only with [U-13C3]lactate or [3-13C]lactate does the labeling pattern of phenylacetylglutamine reflect patterns of liver alpha-ketoglutarate and glutamate. With [13C]acetate, muscle and kidney glutamate are more labeled than liver metabolites. This confirms that with [13C]acetate, the labeling pattern of liver metabolites is influenced by 13CO2 and [13C]glutamine made in peripheral tissues. Our data validate the use of phenylacetylglutamine labeled from [3-13C]lactate or [3-13C]pyruvate to probe noninvasively the pyruvate carboxylase-to-pyruvate dehydrogenase flux ratio in human subjects.