DC current pulses for OTSC clip fragmentation: technology and experimental study.

BACKGROUND: The OTSC clip is used in endoscopic management of gastrointestinal lesions. In rare cases, the removal of the OTSC clip might be desirable. The objective of the study is to investigate feasibility, efficacy, and safety of a novel endoscopic instrument system for removal of the OTSC clip. METHODS: The study series has been conducted in a porcine model. Clip removal is performed with a prototype instrumentation that is designed to locally melt the clip by applying an electrical current pulse onto the clip structure. This system has been evaluated in an animal study (n = 10) in a pig model. A cap prototype with an elongated sleeve has been used for extraction of the OTSC clip fragments. RESULTS: 23 of 24 implanted OTSC clips were successfully opened by applying in a total of 74 current pulses. Superficial mucosal coagulation marks were observed in 14 of the 24 application sites. No other findings such as hemorrhage, deep thermal wall lesions, or perforation were observed. CONCLUSIONS: The study confirms the effectiveness and safety of the proposed endoscopic removal technique. Safe extraction of the clip fragments was feasible with an elongated sleeve at the distal cap. Limitations of the methods are the animal model and the experimental nature of the prototype instrumentation.

An over-the-scope clip (OTSC) system for closure of iatrogenic colon perforations: results of an experimental survival study in pigs.

BACKGROUND AND STUDY AIM: Perforation of the colon is a relatively rare complication of flexible endoscopy of the lower gastrointestinal tract. It has a reported incidence from between 0.2 % in diagnostic procedures to 0.5 % - 3 % in therapeutic procedures. Given the growing number of colonoscopies, the absolute number of iatrogenic perforations is not unimportant. The treatment of choice is most often surgical repair, since reliable and simple endoscopic techniques for perforation closure are currently unavailable. We aimed to evaluate our novel over-the-scope clip (OTSC) system for closure of iatrogenic perforations. MATERIAL AND METHODS: We have developed a nitinol clip that will capture perforations of 10 - 15 mm, compressing the lesions until healing. The OTSC was studied in a prospective experimental trial in pigs (50 - 60 kg, n=10) for the closure of an iatrogenic perforation of approximately 5 --10 mm on the serosal side, that was created by repeated endoscopic biopsy. The follow-up period was 12 weeks. Follow-up colonoscopy was performed at 4 and 12 weeks. Successful, tight closure of the lesion with absence of peritonitis in the postoperative course was the primary endpoint of the study. RESULTS: Nine animals had an uneventful clinical course. At termination of the study, macroscopic and microscopic examination of the clipping sites in the bowel wall showed normal tissue healing. One animal died 1 day postoperatively for reasons unrelated to the procedure. CONCLUSIONS: In this experimental study the OTSC clip system was found to be a simple and secure closure method for iatrogenic colon perforations, and thus might be an alternative to surgical repair.

Wireless therapeutic endoscopic capsule: in vivo experiment.

BACKGROUND AND STUDY AIM: Capsule endoscopy is becoming well established as a diagnostic technique for the gastrointestinal tract. Nevertheless swallowable capsule devices that can effectively perform surgical and therapeutic interventions have not yet been developed. Such devices would also be a valuable support for natural orifice transluminal endoscopic surgery (NOTES). The objective of this study was to assess the feasibility of using a swallowable wireless capsule to deploy a surgical clip under remote control. MATERIALS AND METHODS: A wireless endoscopic capsule, diameter 12.8 mm and length 33.5 mm, was developed. The device is equipped with four permanent magnets, thus enabling active external magnetic steering. A nitinol clip is loaded on the topside of the capsule, ready to be released when a control command is issued by an external operator. Repeated ex vivo trials were done to test the full functionality of the therapeutic capsule in terms of efficiency in releasing the clip and reliability of the remote control. An in vivo test was then carried out in a pig: the capsule was inserted transanally and steered by means of an external magnetic arm towards an iatrogenic bleeding lesion. The clip, mounted on the tip of the capsule, was released in response to a remote signal. The procedure was observed by means of a flexible endoscope. RESULTS: A wireless capsule clip-releasing mechanism was developed and tested. During ex vivo trials, the capsule was inserted into the sigmoid section of a phantom model and steered by means of the external magnet to a specific target, identified by a surgical suture at a distance of 3 cm before the left flexure. The capsule took 3 to 4 minutes to reach the desired location moving under external magnetic guidance, while positioning of the capsule directly on the target took 2 to 3 minutes. Successful in vivo clipping of an iatrogenic bleed by means of a wireless capsule was demonstrated. CONCLUSIONS: This study reports the first successful in vivo surgical experiment using a wireless endoscopic capsule, paving the way to a new generation of capsule devices able to perform both diagnostic and therapeutic tasks.

Survey of polynuclear aromatic compounds in oil refining areas.

Air samples in and around refinery areas were collected over a 3-year period. The results of the analysis for polynuclear aromatic compounds listed as priority pollutants by the United States Environmental Protection Agency are presented. The particulate matters in the air were collected on glass fiber filters using high volume samplers. These samples were later Soxhlet extracted with cyclohexane, and then extracted with DMSO/pentane for isolation of the polynuclear aromatic compounds. These extracts were then analyzed using gas chromatography-mass spectrometry for specified polynuclear aromatic compounds. It was found that much higher concentrations of these aromatic compounds were found in one refinery compared to another one. In general, the number of these priority pollutants detected and their concentrations were higher in sites inside the refineries relative to a site outside the refineries.

Minimally invasive parathyroidectomy by unilateral neck dissection--experience in a regional hospital in Hong Kong.

OBJECTIVE: To compare the efficacy and safety of minimally invasive open parathyroidectomy with localised unilateral neck dissection to the conventional method of bilateral neck exploration and parathyroidectomy as a surgical treatment for primary hyperparathyroidism. PATIENTS AND METHODS: Eleven patients diagnosed with primary hyperparathyroidism at Queen Elizabeth Hospital from 1 January 2002 to 31 December 2002 were treated surgically with minimally invasive open parathyroidectomy. Their results were compared to a retrospective series of 15 patients treated by conventional bilateral neck exploration and parathyroidectomy between 1 January 2001 and 31 December 2001. Demographic data; cure, recurrence, and complication rates; operating time; and hospital stay were analysed. RESULTS: The cure rate was 100% in both groups. There was no recurrence in either group. Minor complication rates were 9% and 20% in the minimally invasive open parathyroidectomy and the control groups, respectively. Mean operating time was 63 minutes in the minimally invasive open parathyroidectomy group, and 92 minutes in the control group. The mean postoperative hospital stay for the minimally invasive open parathyroidectomy group was 1.36 days. Three of these procedures were performed as day surgery. The mean hospital stay for the control group was 2.93 days. The operating time and hospital stay were significantly shorter in the minimally invasive open parathyroidectomy group. CONCLUSION: Minimally invasive open parathyroidectomy is a viable alternative treatment method for primary hyperparathyroidism. It has comparable cure and recurrence rates to the conventional approach. It is safe, with a lower complication rate, and has the benefits of being a shorter procedure and allowing a shorter hospital stay. It can be performed as day surgery, further reducing hospital costs.

[Actuator design and control exemplified by a urologic implant]. / Aktorik und Steuerung Am Beispiel eines Urologischen Implantats.

The state of the art concerning the use of actuators and sensors and the intelligent microprocessor-based control will be discussed on the basis of a novel urological implant, a fine tuned, sensor controlled artificial sphincter. A set of powerful actuators with a reaction time lower than 10 ms have been realised due to an appropriate design of components. This has been achieved at a supply voltage of 4.2 V and a power input lower than 0.1 mW. An optimal reliability as well as the comfort in operating the implant by the physician and the patient was gained by the use of different data technologies being adapted to the implanted system.

Preadolescent adjudicative competence: methodological considerations and recommendations for practice standards.

This article examines developmental and legal issues directed toward a downward age extension of forensic evaluation practice standards for preadolescent defendants whose competence is questioned. Existing research and practice standards were developed for cases involving adolescents and adults, but they lack sufficient application to evaluations of young children because of the ways in which legal parameters affect young children. We review practice implications of the legal role of "immaturity" for adjudicative competence, alterations of Dusky in some juvenile courts, and the role of parens patriae in competence hearings held in juvenile court. We examine competence abilities in a developmental framework. Examining practice standards is timely because adjudicative competence in preadolescent defendants has taken on recent significance. The last decade saw changes in the stringency of delinquency statutes, increased emphasis on adversarial approaches to juvenile proceedings, and a de-emphasis on rehabilitation and parens patriae protections. Statutory changes and increased referrals have heightened inquiry into the meaning of preadolescent adjudicative competence.