Performance of microvascular anastomosis with a new robotic visualization system: proof of concept.

Microvascular procedures require visual magnification of the surgical field, e.g. by a microscope. This can be accompanied by an unergonomic posture with musculoskeletal pain or long-term degenerative changes as the eye is bound to the ocular throughout the whole procedure. The presented study describes the advantages and drawbacks of a 3D exoscope camera system. The RoboticScope®-system (BHS Technologies®, Innsbruck, Austria) features a high-resolution 3D-camera that is placed over the surgical field and a head-mounted-display (HMD) that the camera pictures are transferred to. A motion sensor in the HMD allows for hands-free change of the exoscope position via head movements. For general evaluation of the system functions coronary artery anastomoses of ex-vivo pig hearts were performed. Second, the system was evaluated for anastomosis of a radial-forearm-free-flap in a clinical setting/in vivo. The system positioning was possible entirely hands-free using head movements. Camera control was intuitive; visualization of the operation site was adequate and independent from head or body position. Besides technical instructions of the providing company, there was no special surgical training of the surgeons or involved staff upfront performing the procedures necessary. An ergonomic assessment questionnaire showed a favorable ergonomic position in comparison to surgery with a microscope. The outcome of the operated patient was good. There were no intra- or postoperative complications. The exoscope facilitates a change of head and body position without losing focus of the operation site and an ergonomic working position. Repeated applications have to clarify if the system benefits in clinical routine.

[Robotics in otorhinolaryngology, head and neck surgery]. / Roboterassistierte Chirurgie in der Hals­Nasen-Ohren-Heilkunde.

In many surgical specialities, e.g., visceral surgery or urology, the use of robotic assistance is widely regarded as standard for many interventions. By contrast, in European otorhinolaryngology, robotic-assisted surgery (RAS) is rarely conducted. This is because currently available robotic systems are not adequately adapted to the restricted space and partially difficult access to surgical fields in the head and neck area. Furthermore, RAS is associated with high costs at present. In some Anglo-American regions, robot-assisted surgery is already used regularly for different indications, particularly in transoral surgery of oropharyngeal tumors. Several feasibility studies demonstrate multiple fields of application for RAS in head and neck surgery. For standard use, the robotic systems and surgical instruments need to be reduced in size and adapted to application in the head and neck area.

[Dysphagia in cervical spine diseases]. / Dysphagie bei Erkrankungen der Halswirbelsäule.

Dysphagia is a common symptom and can be indicative of a variety of heterogeneous diseases. "Classical" diseases of the head and neck region, such as acute tonsillitis, peritonsillar abscesses, diverticula, and benign or malignant tumors are common causes of dysphagia. However, it can also occur in the context of neurological diseases, e.g., as a result of stroke or as an age-related phenomenon (presbyphagia). Pathologies of the cervical spine can also be a cause of dysphagia. In this context, congenital or acquired diseases, inflammatory or degenerative processes, cervical spine surgery, and (malignant) masses of the cervical spine should be taken into account. Particular dysphagia with a positive history of previous operative interventions on the cervical spine or symptoms such as chronic back pain and trauma should give rise to consideration of a cervical spine-related cause.

[Diagnostic accuracy of outpatient polygraphy devices : A comparison with inpatient polysomnography in clinical routine]. / Diagnostische Genauigkeit ambulanter Polygraphiegeräte : Ein Vergleich zur stationären Polysomnographie im klinischen Alltag.

BACKGROUND: Cardiorespiratory polysomnography (PSG) is considered the reference method for diagnosis of obstructive sleep apnea (OSA). Due to waiting times and high costs, payers increasingly request outpatient polygraphy (PG) as an alternative to inpatient PSG. The aim of the present study was to evaluate the diagnostic accuracy of different outpatient PG devices compared to stationary PSG in clinical practice. MATERIALS AND METHODS: Externally collected outpatient PG findings of 406 patients were retrospectively compared with the corresponding PSG findings. RESULTS: Among the 406 patients were 343 men (85%) and 63 women (15%), with mean age 50 years. Mean body mass index (BMI) was 30 kg/m2. The rank correlation coefficient for PG- and PSG- derived apnea-hypopnea index (AHI) values was r = 0.574. On average, PG underestimated the AHI by 6.4 (±20.5) events/h. OSAS severity was determined correctly by PG in only 43% of cases. Sensitivity (90.7%) and specificity (45.2%) of ambulatory PG was calculated for the threshold value AHI ≥ 5/h. Based on the results of PG, an indicated therapy would have been omitted in 35 cases (9%) and unnecessary treatment initiated in 17 cases (4%). The PG devices used showed a comparable diagnostic accuracy (r = 0.513-0.657), with a sensitivity of 81.3-96.9% and a specificity of 33.3-50.0%. CONCLUSION: Outpatient PG cannot reliably assess OSA severity in clinical routine. Confirmation by PSG in a sleep lab in symptomatic patients is obligatory. Outpatient PG devices should only be used as an upstream screening method. The automatic evaluation of the PG should always be proofed.

[Drug therapy of otorhinolaryngological diseases in pregnancy : An update]. / Medikamentöse Therapie HNO­ärztlicher Krankheitsbilder in der Schwangerschaft : Ein Update.

The majority of women take at least one form of medication during pregnancy. Due to often discrepant information about the risk assessment of pharmaceuticals during pregnancy, physicians are often beset by uncertainty with respect to prescription and the fear of medicolegal consequences is high. As prospective clinical trials on drug safety during pregnancy are prohibited due to ethical reasons and animal studies are of limited applicability to humans, drug recommendations often only rely on observational data. An objective examination of the topic not only contributes to effective treatment of illnesses in pregnancy but also prevents impairment of fetal outcome by omission of necessary maternal treatment. The aim of this article is to give a structured presentation of medications that can be used during pregnancy for treating medical conditions of the ear, nose and throat, in the sense of practical guidelines.

Transnasal endoscopic treatment of bilateral choanal atresia in newborns using balloon dilatation: own results and review of literature.

OBJECTIVES: Congenital choanal atresia is a complete obliteration of the posterior nasal aperture leading to life-threatening airway emergencies. Several surgical options including sublabial, transpalatal, transseptal or external approaches have been developed for the repair of choanal atresia. So far, no gold standard has been established, but transnasal endoscopic approaches have been favored by many surgeons in recent years. METHODS: Since 2008 a standard procedure for bilateral choanal atresia repair in neonates using an endoscopic transnasal approach supported by balloon dilatation has been established at the Department of Otorhinolaryngology at Ulm University Medical Center. During the last five years, six cases of bilateral choanal atresia were diagnosed and treated, including two male and four female patients aged between three days and two months, at the date of surgery. All interventions were performed in transnasal endoscopic technique. In all patients the abnormally thick posterior vomer and the atretic bony plate were resected and the mucosa was perforated. A balloon dilator was used to dilate the neochoanae and prevent restenosis. All six patients were intraoperatively stented for at least six weeks. RESULTS: All six neonates with bilateral choanal atresia, who were operated in endoscopic transnasal technique had patent neo-choanae on both sides. No severe postoperative complications were found. The number of revisions depends on the age at primary surgery. CONCLUSIONS: Endonasal endoscopic approach and balloon dilatation is a safe, reproducible technique for surgical repair of choanal atresia. We recommend the use of bilateral stents, especially in very young patients, as a prerequisite to prevent early restenosis.

Circadian variation of rectal sensitivity and gastrointestinal peptides in healthy volunteers.

The aim of our study was to identify diurnal variation of perception of rectal distension and the release of gastroenteropancreatic hormones. In 12 healthy male volunteers (25 years, range 22-32), a rectal balloon distension was performed. Rectal perception thresholds (minimal, urge and pain) and rectal compliance were double-measured with a computer-controlled barostat at seven standardized time points during the day (from 16.00 to 14.00 hours the following day). Blood samples were taken 30 min before and after each rectal distension procedure to determine plasma levels of cholecystokinin (CCK), pancreatic polypeptide (PP) and motilin. Sensory thresholds for urge and pain varied significantly with the time of day, with higher threshold levels in the evening than in the morning hours. Bowel wall compliance showed as well-significant variance at pain threshold and was higher during daytime than in the evening or at night. In contrast to motilin, release of CCK and PP also showed a significant variation depending on daytime. Perception of rectal distension stimuli as well as compliance was independent of intake of food and peptide hormone levels, but CCK and PP levels increased with food, and PP levels decreased with rectal distension. Significant differences in the perception of rectal distension stimuli for urge and pain depending on daytime were found, but the release of gastrointestinal peptides seemed not to be involved. This circadian variation needs to be taken into account in patients and volunteer studies.

Effects of euglycemic hyperinsulinemia and lipid infusion on circulating cholecystokinin.

AIMS: Functions of the gut hormone cholecystokinin (CCK) include an important role in the regulation of gastric emptying, postprandial glucose homeostasis, and postmeal satiety. Postprandial CCK responses are significantly blunted in type 2 diabetic patients by unknown mechanisms. We hypothesized that hyperinsulinemia and lipid infusion influence circulating levels of biologically active CCK. METHODS: Eleven healthy subjects were studied in a cross-over design after 10-h overnight fasts, using euglycemic-hyperinsulinemic clamps for 443 min, with an additional infusion of lipid-heparin (1.25 ml.min(-1)) or saline (1.25 ml.min(-1)) for the last 300 min after constant plasma glucose levels were achieved. RESULTS: Euglycemic-hyperinsulinemia resulted in a sustained, up to 5-fold increase of plasma CCK (P < 0.001). When adding lipid infusion instead of saline, CCK concentrations rapidly declined and returned to baseline levels (CCK(300 min) 1.1 +/- 0.2 vs. 3.3 +/- 0.3 pmol/liter, P < 0.001). Partial intraclass correlation showed an independent correlation of plasma CCK with free fatty acids (r(ic) = -0.377, P < 0.001) but not with serum insulin (r(ic) = 0.077, P = 0.32). Whole-body insulin sensitivity decreased in lipid-exposed subjects (M value 7.1 +/- 0.7 vs. 5.6 +/- 0.9 mg.kg.min(-1), P = 0.017) but was not independently correlated with CCK (r(ic) = 0.040, P = 0.61). CONCLUSIONS: We report novel findings showing that circulating CCK markedly increased in the euglycemic-hyperinsulinemic state, possibly as a result of near-complete suppression of circulating free fatty acids. Moreover, raising blood lipids even moderately by lipid infusion rapidly and significantly interfered with this effect, suggesting that a negative feedback mechanism of blood lipids on circulating CCK might exist.

Peptide YY release in anorectic patients after liquid meal.

Fasting and postprandial levels of human peptide YY (PYY) were recently found to be lower in obesity. To investigate whether PYY levels are correspondingly high in patients with anorexia nervosa, PYY concentrations were analyzed under basal conditions and in response to a liquid meal. We investigated PYY plasma levels in 16 female anorectic (BMI 15.2+/-0.3 kg/m2) and seven lean subjects (BMI 21.3+/-0.6 kg/m2) before and after ingestion of a liquid meal (250 kcal; 15% protein, 55% carbohydrates, and 30% fat). PYY levels were analyzed using PYY ELISA (DSL, USA). Values are given as mean+/-SEM. Basal PYY levels in anorectic patients (89.0+/-14.4 pg/mL) were not significantly different from lean subjects (64.1+/-12.1 pg/mL). Postprandial PYY levels in healthy volunteers increased significantly after 20 and 60 min (80.4+/-12.7 and 96.0+/-19.9 pg/mL, respectively). In anorectic women PYY was increased at 20 min (137.9+/-19.5 pg/mL) and at 60 min (151.3+/-19.2 pg/mL). No difference was found between both groups. We conclude that basal and postprandial PYY levels in normal weight women are not different from anorectic patients. We could not confirm the recently published blunted postprandial PYY response in anorexia, a finding that merits further study.

mu-Opiate receptor agonist loperamide blocks bethanechol-induced gallbladder contraction, despite higher cholecystokinin plasma levels in man.

UNLABELLED: mu-Opiate receptor agonists, such as loperamide, influence biliary excretion and suppress cholecystokinin (CCK)-induced gallbladder contraction. Loperamide decreases cholinergic mechanisms, like pancreatic polypeptide (PP) release, while muscarinic agonist (bethanechol)-induced PP release remains unaffected. The effects of loperamide on gallbladder contraction and peptide release were performed to resolve this discrepancy. METHODS: Six subjects (27.6 +/- 2.0 years) received bethanechol (12.5, 25 and 50 microg kg(-1) h(-1) continuously over 40 min) after oral 16 mg loperamide (vs placebo) in a crossover design. Gallbladder volume and plasma levels of CCK, PP, motilin, gastrin, neurotensin, cholylglycine were measured regularly. RESULTS: Bethanechol significantly reduced gallbladder volume (26.7 +/- 1.9 to a nadir of 15.3 +/- 2.2 mL, P < or = 0.05), and this action was inhibited by loperamide. Basal CCK levels increased significantly after loperamide. Incremental integrated CCK release after bethanechol was higher under loperamide (P < or = 0.05), as placebo CCK release was significantly decreased under bethanechol (2.0 +/- 0.4-0.8 +/- 0.3 pmol L(-1)). In both settings, PP levels were significantly increased after bethanechol, while release of neurotensin, motilin, gastrin and cholylglycine was unaffected. CONCLUSION: The mu-opiate receptor agonist loperamide inhibits bethanechol-induced gallbladder contraction. This effect is not mediated by inhibition of CCK release, as loperamide even enhances basal CCK plasma levels. As cholinergic mechanisms, like bethanechol-induced incremental PP release, were unaffected, mu-opiate agonists might influence gallbladder contraction via vagal-cholinergic pathways.

Gastric emptying of solid and liquid meals in healthy controls compared with long-term type-1 diabetes mellitus under optimal glucose control.

BACKGROUND: Neuropathy of the enteric nervous system and hyperglycaemia are regarded as the main causes of diabetic gastroparesis. PATIENTS AND METHODS: In ten patients with Type-1 diabetes mellitus and sensomotoric neuropathy gastric emptying half times were compared with ten healthy controls by employing the 13C-octanoic acid and the 13C-sodiumacetate breath test, resp., following the intake of equally composed and isocaloric liquid and solid meals. Plasma glucose concentrations were controlled by permanent intravenous administration of insulin. RESULTS: In diabetes mellitus gastric emptying half times after the intake of the liquid meal (p < 0.05) but not after ingestion of the solid meal were slightly prolonged. Gastric emptying half times in patients and controls were not different when liquid and solid meals were compared. CONCLUSIONS: Acute hyperglycaemia appears to be more important than the neuropathy of the enteric nervous system in the pathophysiology of diabetic gastroparesis. The rate of gastric emptying is obviously not dependent on the phase of a meal, but rather on the composition and the caloric content.

Weight gain decreases elevated plasma ghrelin concentrations of patients with anorexia nervosa.

OBJECTIVE: Ghrelin is a new gastric hormone that has been identified as an endogenous ligand for the growth hormone (GH) secretagogue receptor subtype 1a (GHS-R1a). Ghrelin administration however not only stimulates GH secretion but also induces adiposity in rodents by increasing food intake and decreasing fat utilization. We hypothesized that impaired ghrelin secretion in anorexia nervosa may be involved in the pathogenesis of this eating disorder. To examine this hypothesis and to further investigate the role for ghrelin in regulating energy homeostasis, we analyzed circulating ghrelin levels in patients with anorexia nervosa and examined possible correlations with clinical parameters before and after weight gain. METHODS: Plasma ghrelin levels were measured in overnight fasting plasma samples from 36 female patients with anorexia nervosa (age: 25.0+/-1.2 years, BMI: 15.2+/-0.2 kg/m(2)) before and after weight gain following psychotherapeutic treatment intervention in a psychosomatic institution. Plasma ghrelin levels were also measured in fasting plasma samples from 24 age-matched female controls (31+/-1.4 years, BMI: 22.9+/-0.45 kg/m(2)). For quantification of ghrelin levels a commercially available radioimmunoassay (Phoenix Pharmaceuticals, USA) was used. RESULTS: Fasting plasma ghrelin levels in anorectic patients were significantly higher (1057+/-95 pg/ml) than in normal age-matched female controls (514+/-63 pg/ml n=24, P=0.02). Therapeutic intervention in a psychosomatic institution caused an BMI increase of 14% (P<0.001) leading to a significant decrease in circulating ghrelin levels of 25%, (P=0.001). A significant negative correlation between Deltaghrelin and DeltaBMI was observed (correlation coefficient: -0.47, P=0.005, n=36). CONCLUSION: We show for the first time that fasting plasma levels of the novel appetite-modulating hormone ghrelin are elevated in anorexia nervosa and return to normal levels after partial weight recovery. These observations suggest the possible existence of ghrelin resistance in cachectic states such as caused by eating disorders. Future studies are necessary to investigate putative mechanisms of ghrelin resistance such as a possible impairment of intracellular ghrelin receptor signaling in pathophysiological states presenting with cachexia.

Post-prandial decrease of circulating human ghrelin levels.

Ghrelin, an endogenous ligand of the GH secretagogue-receptor, has recently been shown to stimulate GH secretion and to have orexigenic and adipogenic effects in rodents, but little is known about its regulation and biological function in humans. Gastric motor function is under control of the central nervous system; however, the afferent and efferent loops of this feedback control mechanism remain to be elucidated. In the study presented here we investigated the effect of nutrient intake on circulating human ghrelin levels, and a possible association between ghrelin levels and gastric emptying. Ten healthy volunteers received a standard meal after an overnight fast. Food intake significantly decreased plasma ghrelin levels from 248.5 +/- 15.0 to 179.5 +/- 17.9 fmol/ml (120 min after meal, p=0.047). Gastric emptying half-time (non-invasive 13C-octanoic acid breath test) was correlated with fasting plasma ghrelin levels (r=0.74, p=0.0013). Ghrelin appears to be one possible candidate to provide feedback signaling between nutrient intake, gastric motor function and the central nervous system.

Pavlovian conditioning of taste aversion using a motion sickness paradigm.

OBJECTIVE: Pavlovian conditioning of taste aversion has rarely been investigated in healthy humans using motion sickness as the unconditioned stimulus (US). METHODS: Ninety subjects were pretested for susceptibility to illusory motion (vection) in a rotating drum. Thirty-two subjects susceptible to pseudomotion were assigned randomly to two groups and received either water 1 hour before rotation and a novel taste (elderberry juice, conditioned stimulus, [CS]) immediately before rotation in a rotating chair (conditioning group), or the sequence of water and juice was reversed (control group). During the test session 1 week later, all subjects were exposed to water 1 hour before and juice immediately before rotation. The amount of liquids ingested, nausea ratings, rotation tolerance, and blood levels of hormones (ACTH, ADH, PP) were evaluated. RESULTS: Subjects in the conditioning group developed taste aversion toward the novel taste, but not subjects in the control group. Postrotation nausea rating was affected marginally by conditioning, but rotation tolerance was not changed by conditioning. ACTH and ADH but not PP levels increased with rotation, but were unaffected by conditioning. CONCLUSIONS: Pavlovian conditioning of behavioral, but not of endocrine, indicators was effective in susceptible subjects using a rotating chair as US and a single CS-US pairing.

High altitude increases circulating interleukin-6, interleukin-1 receptor antagonist and C-reactive protein.

Hypoxic pulmonary vasoconstriction is associated with but may not be sufficient for the development of high-altitude pulmonary oedema (HAPO). Hypoxia is known to induce an inflammatory response in immune cells and endothelial cells. It has been speculated that hypoxia-induced inflammatory cytokines at high altitude may contribute to the development of HAPO by causing capillary leakage in the lung. We were interested if such an inflammatory response, possibly involved in a later development of HAPO, is detectable at high altitude in individuals without HAPO. We examined the plasma levels of interleukin 6 (IL-6), interleukin 1 receptor antagonist (IL-1ra) and C-reactive protein (CRP) in two independent studies: study A, Jungfraujoch, Switzerland, three overnight stays at 3458 m, n=12; study B: Capanna Regina Margherita, Italy, 3 overnight stays at 3647 m and one overnight stay at 4559 m, n=10. In both studies, probands showed symptoms of acute mountain sickness but no signs of HAPO. At the Jungfraujoch, IL-6 increased from 0.1+/-0.03 pg/ml to 2. 0+/-0.5 pg/ml (day 2, P=0.03), IL-1ra from 101+/-21 to 284+/-73 pg/ml (day 2, P=0.01), and CRP from 1.0+/-0.4 to 5.8+/-1.5 micrograms/ml (day 4, P=0.01). At the Capanna Margherita, IL-6 increased from 0. 5+/-0.2 pg/ml to 2.0+/-0.8 pg/ml (P=0.02), IL-1ra from 118+/-25 to 213+/-28 pg/ml (P=0.02), and CRP from 0.4+/-0.03 to 3.5+/-1.1 micrograms/ml (P=0.03). IL-8 was below the detection limit of the ELISA (<25 pg/ml) in both studies. The increase of IL-6 and IL-1ra in response to high altitude was delayed and preceded the increase of CRP. We conclude that: (1) circulating IL-6, IL-1ra and CRP are upregulated in response to hypobaric hypoxic conditions at high altitude, and (2) the moderate systemic increase of these inflammatory markers may reflect considerable local inflammation. The existence and the kinetics of high altitude-induced cytokines found in this study support the hypothesis that inflammation is involved in the development of HAPO.

Accuracy of 13C-urea breath test in clinical use for diagnosis of Helicobacter pylori infection.

UNLABELLED: The 13C-urea breath test (UBT) is a noninvasive test for diagnosis of Helicobacter pylori infection of gastric mucosa. The aim of this prospective study was to assess the accuracy of a simple UBT in clinical routine use. METHODS: The study population comprised of 100 patients (49 f, 51 m) requiring diagnostic upper GI endoscopy. One biopsy specimen was taken from the gastric antrum, body and fundus, respectively, for standard histological examination and one additional specimen from each location was transformed into transport medium for cultivation of H. pylori. After vaccination of the culture plates the biopsies were tested for urease activity (UAT). After recovery from endoscopy the patients had to pass an one liter endexspiratory breath sample before and 15 min after drinking 200 ml orange juice, pH 3.6, containing 75 mg of 13C-urea. 13CO2 was measured in the breath samples using isotope-selective nondispersive infrared spectrometry. RESULTS: Defining gold standard groups with all biopsy tests (from antrum and corpus) positive or negative the 13CO2 delta over baseline (DOB) cut-off level of UBT was set at 6.5/1000 in order to best discriminate positive from negative patients (ROC analysis). UBT was positive in 37% of all subjects. Taken UAT and histological examination together (positive when both tests were positive) UBT displayed a sensitivity of 92%, a specificity of 94%, a positive predictive value of 89%, and a negative predictive value of 94%. When including the results of culture sensitivity and negative predictive value reached almost 100%. The mean of the 13CO2-DOB values from H. pylori-positive duodenal or gastric ulcer patients did not differ from controls (H. pylori-positive patients without lesions). The 13CO2-DOB values of the ulcer group were correlated significantly with the active inflammatory component of gastritis in antrum, corpus, and fundus. CONCLUSION: UBT with this setup detects H. pylori infection in clinical routine use with high accuracy. The increase of exhaled 13CO2 does not predict ulcer disease but reflects the degree of active inflammation of gastric mucosa.