Extensive circumferential endoscopic mucosal resection with a new rigid esophagoscope: an animal study

RÉSUME Les techniques de résection muqueuse endoscopique utilisées actuellement ne permettent pas d'effectuer une résection circonférentielle d'un long segment de muqueuse oesophagienne. Une telle résection permettrait le traitement de foyers multicentriques de dysplasies de haut grade (HGIN) ou d'adénocarcinomes précoces (AC) développés sur oesophage de Barrett. Sachant que la prévalence des métastases ganglionnaires régionales est d'environ 7 % pour les adénocarcinomes intra-muqueux (Tis,T1a), les méthodes de traitement non-chirurgicales et moins invasives sont actuellement préférées à une oesophagectomie, dont la morbidité et la mortalité restent élevées en comparaison avec les mucosectomies endoscopiques. Un oesophagoscope rigide modifié a été développé à Lausanne en collaboration avec la maison Karl Storz GmbH, de façon à permettre des résections muqueuses étendues dans l'oesophage. Cette étude animale pilote a investigué la faisabilité et la fiabilité des résections muqueuses circonférentielles de différentes longueurs dans l'oesophage du mouton. Des résections circonférentielles de 2,2 cm (n=6), 3,3 cm (n=6), 4,4 cm (n=7) et 5,5 cm (n=5) de longueur ont été effectuées dans l'oesophage de 24 moutons. Elles consistaient en 2 mucosectomies hémi-circonférentielles opposées. Les animaux ont été suivis par des examens endoscopiques à une semaine puis chaque mois pendant 6 mois ou jusqu'à réépithélialisation complète sans sténose. Au cours du processus de guérison, les sténoses cicatricielles ont été traitées par une ou plusieurs dilatations avec les bougies de Savary. Des résections circonférentielles de 2,2 à 5,5 cm de longueur ont été réalisées avec succès dans 23/24 des cas. Une seule perforation, secondaire à une erreur de manipulation, est survenue directement après la mucosectomie. A l'analyse histologique, une profondeur de résection précise à travers la sousmuq Tyrp1ueuse a été obtenue dans 85% des specimens. Les sténoses cicatricielles ont été contrôlées dans 95% des cas par dilatations avec les bougies de Savary. L'oesophagoscope rigide modifié a permis de réaliser des résections muqueuses circonférentielles et étendues en une seule séance endoscopique d'une durée de moins d'une demi-heure. L'utilisation de ce résectoscope chez l'homme devrait permettre l'éradication complète de l'oesophage de Barrett avec HGIN et/ou AC précoce dans un avenir très proche.

Stricture prevention after extended circumferential endoscopic mucosal resection by injecting autologous keratinocytes in the sheep esophagus.

BACKGROUND: During the past decades, endoscopic mucosal resection (EMR) has been developed to treat early intramucosal esophageal cancers and dysplastic Barrett's esophagus. The primary drawback of this method is severe postsurgical esophageal stricture formation. The purpose of this preclinical study was to assess strategies for prevention of this major complication by injecting autologous keratinocytes in the EMR mucosal defect in the sheep model. METHODS: Circumferential, 6-cm-long EMRs were performed in the esophagus of nine sheep. Autologous keratinocytes were harvested 2 weeks before EMR and cultured. Circumferential resection consisted of two opposite hemicircumferential mucosectomies allowing a widespread resection of 24 cm(2). Immediately after EMR, autologous keratinocytes were endoscopically injected in the mucosal defect. Animals were sacrificed after 6 months. RESULTS: Circumferential EMRs were successfully performed in all animals. There were no intra- or postoperative complications. None of the animals developed strictures. All animals were sacrificed at 6 months as planned. Histological examinations showed fibrotic changes in 10 % (range 0-25 %) of the circumferential muscularis propria interna layer and 7.2 % (range 0-25 %) in the muscularis propria externa layer at the midportion of the EMR. No circumferential transmural fibrosis was identified. CONCLUSIONS: Prevention of stricture formation after extensive (6-cm long) circumferential EMR of the sheep esophagus can be achieved by injecting autologous keratinocytes into the wound of the resected mucosal segment.

Artificial-Intelligence-Based Optimization of the Management of Snow Removal Assets and Resources Final Report, October 2002

Geographic information systems (GIS) and artificial intelligence (AI) techniques were used to develop an intelligent snow removal asset management system (SRAMS). The system has been evaluated through a case study examining snow removal from the roads in Black Hawk County, Iowa, for which the Iowa Department of Transportation (Iowa DOT) is responsible. The SRAMS is comprised of an expert system that contains the logical rules and expertise of the Iowa DOT’s snow removal experts in Black Hawk County, and a geographic information system to access and manage road data. The system is implemented on a mid-range PC by integrating MapObjects 2.1 (a GIS package), Visual Rule Studio 2.2 (an AI shell), and Visual Basic 6.0 (a programming tool). The system could efficiently be used to generate prioritized snowplowing routes in visual format, to optimize the allocation of assets for plowing, and to track materials (e.g., salt and sand). A test of the system reveals an improvement in snowplowing time by 1.9 percent for moderate snowfall and 9.7 percent for snowstorm conditions over the current manual system.

Endoscopic extraction of a prevertebral migrated guidewire after posterior cervical instrumentation.

Images of Spine Care

Upper gastrointestinal bleeding in cirrhosis: clinical and endoscopic correlations

The clinical data of 180 episodes of upper gastrointestinal bleeding in 168 patients with cirrhosis of the liver are examined. The source of bleeding had been determined by early endoscopy in all cases. In men under the age of 50 years, and without symptoms of liver failure, bleeding was due to ruptured gastro-oesophageal varices in 84% of cases. Severe liver failure was associated with acute lesions of gastric mucosa in many cases. No presumptive diagnosis of the source of haemorrhage could be based on the examination of other clinical data (presence of ascites, mode of presentation and pattern of bleeding, history of ulcer disease, alcoholism, and previous medication.

Upper gastrointestinal bleeding in cirrhosis: clinical and endoscopic correlations

The clinical data of 180 episodes of upper gastrointestinal bleeding in 168 patients with cirrhosis of the liver are examined. The source of bleeding had been determined by early endoscopy in all cases. In men under the age of 50 years, and without symptoms of liver failure, bleeding was due to ruptured gastro-oesophageal varices in 84% of cases. Severe liver failure was associated with acute lesions of gastric mucosa in many cases. No presumptive diagnosis of the source of haemorrhage could be based on the examination of other clinical data (presence of ascites, mode of presentation and pattern of bleeding, history of ulcer disease, alcoholism, and previous medication.

Endoscopic and surgical treatment of vesico-ureteral reflux in children. Comparative long-term follow-up.

PRINCIPLES: This retrospective study analyzes the long-term results of endoscopic and surgical treatment of vesico-ureteral reflux in children. METHODS: A cohort of 130 patients, 67 girls and 63 boys with a mean age of 30 months were treated either by endoscopic subureteral collagen injection (SCIN) in 92 and by Cohen reimplantation surgery in 123 refluxing ureteral units. Mean follow-up was 4.2 years varying from 1 to 8.7 years. Reflux recurrence, urinary tract infection (UTI) and renal function were evaluated. RESULTS: After SCIN reflux was absent in 64% at 6 months. 20% of the initially 92 refluxing ureters were injected twice. After one or two injections reflux was absent in 71%. In 21% recurrent reflux was of grade I or II, not requiring further treatment. UTI was observed in 27%. After Cohen ureteral reimplantation reflux was absent in 96% at 6 months. UTI was observed in 23%. Renal function at diagnosis and follow-up was compared in children with bilateral grade III reflux only. In patients treated with SCIN it was normal in 77% preoperatively and in 90% at follow-up. In patients treated by open surgery it was normal in 47% preoperatively and in 76% at follow-up. CONCLUSION: For high-grade vesico-ureteral reflux re-implantation surgery remains the gold standard. SCIN is indicated for low and medium grade reflux. Recurrent bacteriuria was observed more often after SCIN and pyelonephritis more often after open surgery. The renal function seems to be preserved with both techniques.

Occam's razor in minimally invasive pituitary surgery: tailoring the endoscopic endonasal uninostril trans-sphenoidal approach to sella turcica.

BACKGROUND: Since the introduction of the endoscopic endonasal approaches in the field of skull base surgery during the last two decades, several variants of the sella turcica endoscopic surgery have been described. The aim of this study is to provide a stepwise description of one of these variants in a minimally invasive/maximally efficient perspective. METHOD: For the majority of our sella turcica pathologies, we have progressively adopted a uninostril endoscopic approach that is very conservative towards the nasal mucosa with a very limited mucosal incision, resection of the vomer and allowing an almost ad integrum sellar floor reconstruction, without compromising the efficacy and completeness of both surgical oncologic and endocrine targets. CONCLUSION: The uninostril trans-sphenoidal endoscopic endonasal approach to sella turcica is tailored to ally maximal efficiency and minimal invasiveness.

Benefits of endoscopic vein harvesting.

The purpose of this study was to evaluate and compare the benefits of endoscopic saphenous vein harvesting (EVH) with the traditional incision technique (TIT) for coronary artery bypass grafting (CABG) in respect to the technical procedure and clinical outcome. In a prospective nonrandomized, case-matched study the greater saphenous vein was harvested for CABG in 22 patients using the endoscopic technique and in 18 patients with the traditional method. Comparisons were made for the operating time, length of incision and vein harvested, graft quality, postoperative complications, and pain assessment. Patient demographics were well matched. EVH required smaller incisions than did the TIT (10.5 +/- 6.6 vs. 31.2 +/- 7.8 cm, respectively; p < 0.0001). Harvest time and vein quality were comparable in the two groups. Total vein operating time was shorter following the endoscopic technique (60 +/- 24 vs. 100 +/- 35 minutes, respectively; p < 0.0001). EVH had fewer complications (NS), and postoperative pain was significantly less (p = 0.0034). The major advantages of endoscopic vein harvesting are a significant reduction of postoperative pain and strikingly better cosmetic results. Wound complications seem to be less frequent.

Esophageal and pharyngeal strictures: report on 1,862 endoscopic dilatations using the Savary-Gilliard technique

Treatment of symptomatic pharyngeal and esophageal strictures requires endoscopic dilatation. The Savary-Gilliard bougienage was developed by our department and has been used since 1980 for this purpose. We report our experience using this technique. The records of patients seen from January 1, 1963 to December 31, 2005, who had pharyngeal and esophageal strictures needing dilatation, were reviewed. The prevalence of different etiologies, and the incidence of complications using the Savary-Gilliard dilators were assessed. Efficiency of dilatation was assessed over a 17-year segment of this period, using number of dilatations and time intervals between dilatations until resolution of symptoms as outcome measures. Of the 2,652 pharyngeal and esophageal strictures reviewed, 90% were of organic origin (45% benign and 55% malignant stenoses), and 10% were of functional etiology. The most common etiologies were peptic strictures before the era of proton pump inhibitors, and postoperative anastomotic strictures thereafter. A total of 1,862 dilatations using the Savary-Gilliard technique were analyzed. Complication and mortality rates were 0.18 and 0.09% for benign and 4.58 and 0.81% for malignant etiologies, respectively. The number of dilatations per stricture and the time interval between different sessions were dependent on the type of strictures, varying from 1 to 23 dilatations and 7 days to 16 years, respectively. Pharyngeal and esophageal dilatations using the Savary-Gilliard technique were safe when used together with fluoroscopy. Overall, the efficiency of the dilatation procedure was good, but some types of strictures (e.g., caustic, post-surgical and/or post radiotherapy) were refractory to treatment and required repeated dilatations.

Effects of riparian vegetation removal on nutrient retention in a Mediterranean stream

We examined the effects of riparian vegetation removal on algal dynamics and stream nutrient retention efficiency by comparing NH4-N and PO4-P uptake lengths from a logged and an unlogged reach in Riera Major, a forested Mediterranean stream in northeastern Spain. From June to September 1995, we executed 6 short-term additions of N (as NH4Cl) and P (as Na2HPO4) in a 200-m section to measure nutrient uptake lengths. The study site included 2 clearly differentiated reaches in terms of canopy cover by riparian trees: the first 100 m were completely logged (i.e., the logged reach) and the remaining 100 m were left intact (i.e., the shaded reach). Trees were removed from the banks of the logged reach in the winter previous to our sampling. In the shaded reach, riparian vegetation was dominated by alders (Alnus glutinosa). The study was conducted during summer and fall months when differences in light availability between the 2 reaches were greatest because of forest canopy conditions. Algal biomass and % of stream surface covered by algae were higher in the logged than in the shaded reach, indicating that logging had a stimulatory effect on algae in the stream. Overall, nutrient retention efficiency was higher (i.e., shorter uptake lengths) in the logged than in the shaded reach, especially for PO4-P. Despite a greater increase in PO4-P retention efficiency relative to that of NH4-N following logging, retention efficiency for NH4-N was higher than for PO4-P in both study reaches. The PO4-P mass-transfer coefficient was correlated with primary production in both study reaches, indicating that algal activity plays an important role in controlling PO4-P dynamics in this stream. In contrast, the NH4-N mass-transfer coefficient showed a positive relation-ship only with % of algal coverage in the logged reach, and was not correlated with any algal-related parameter in the shaded reach. The lack of correlation with algal production suggests that mechanisms other than algal activity (i.e., microbial heterotrophic processes or abiotic mechanisms) may also influence NH4-N retention in this stream. Overall, this study shows that logging disturbances in small shaded streams may alter in-stream ecological features that lead to changes in stream nutrient retention efficiency. Moreover, it emphasizes that alteration of the tight linkage between the stream channel and the adjacent riparian zone may directly and indirectly impact biogeochemical processes with implications for stream ecosystem functioning.