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1.
Gastrointest Endosc ; 97(2): 325-334.e1, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36208795

RESUMEN

BACKGROUND AND AIMS: Computer-assisted detection (CADe) is a promising technologic advance that enhances adenoma detection during colonoscopy. However, the role of CADe in reducing missed colonic lesions is uncertain. The aim of this study was to determine the miss rates of proximal colonic lesions by CADe and conventional colonoscopy. METHODS: This was a prospective, multicenter, randomized, tandem-colonoscopy study conducted in 3 Asian centers. Patients were randomized to receive CADe or conventional white-light colonoscopy during the first withdrawal of the proximal colon (cecum to splenic flexure), immediately followed by tandem examination of the proximal colon with white light in both groups. The primary outcome was adenoma/polyp miss rate, which was defined as any adenoma/polyp detected during the second examination. RESULTS: Of 223 patients (48.6% men; median age, 63 years) enrolled, 7 patients did not have tandem examination, leaving 108 patients in each group. There was no difference in the miss rate for proximal adenomas (CADe vs conventional: 20.0% vs 14.0%, P = .07) and polyps (26.7% vs 19.6%, P = .06). The CADe group, however, had significantly higher proximal polyp (58.0% vs 46.7%, P = .03) and adenoma (44.7% vs 34.6%, P = .04) detection rates than the conventional group. The mean number of proximal polyps and adenomas detected per patient during the first examination was also significantly higher in the CADe group (polyp: 1.20 vs .86, P = .03; adenoma, .91 vs .61, P = .03). Subgroup analysis showed that CADe enhanced proximal adenoma detection in patients with fair bowel preparation, shorter withdrawal time, and endoscopists with lower adenoma detection rate. CONCLUSIONS: This multicenter trial from Asia confirmed that CADe can further enhance proximal adenoma and polyp detection but may not be able to reduce the number of missed proximal colonic lesions. (Clinical trial registration number: NCT04294355.).


Asunto(s)
Adenoma , Neoplasias del Colon , Pólipos del Colon , Masculino , Humanos , Persona de Mediana Edad , Femenino , Pólipos del Colon/diagnóstico por imagen , Pólipos del Colon/patología , Estudios Prospectivos , Colonoscopía , Adenoma/diagnóstico , Adenoma/patología , Computadores , Neoplasias del Colon/diagnóstico , Neoplasias del Colon/patología
2.
Surg Innov ; 29(2): 215-224, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33980081

RESUMEN

Purpose. The emergence of robotic-assisted surgical techniques has gained significant indications in terms of reduced trauma, shortened recovery, and higher patients' satisfaction. However, limitations by present surgical robotic systems used in natural orifice transluminal endoscopic surgery (NOTES) gynecology still exists, such as arm collisions, countertraction, instrument dexterity, and, in particular, space confinement due to the narrow pelvic anatomy. The current study evaluated the use of a miniaturized single-site surgical robotic system and its feasibility in performing robotic NOTES gynecological procedures using a live porcine animal model. Methods. Using a transrectal approach, the fully internalized robotic arms were deployed in a reverse configuration to access the lower pelvic cavity of the animals to perform NOTES gynecological procedures. Results. Robotic-assisted transrectal gynecological procedures were successfully performed using the new robotic system. A hemi-hysterectomy with unilateral salpingo-oophorectomy was completed in the first animal and a total hysterectomy with bilateral salpingo-oophorectomy in the second animal with an average docking time of 22.5 minutes and console time of 63 minutes and 58 minutes, respectively. The overall blood loss for each procedure was estimated to be <20 mL per animal with no intraoperative complications. Conclusions. The reverse configuration of the miniaturized surgical robotic system has demonstrated its capability to provide a potential solution to maintain clear visualization of the surgical field, optimal triangulation, and dexterity robotic NOTES gynecological procedures within the deep confined space of the pelvic cavity.


Asunto(s)
Laparoscopía , Cirugía Endoscópica por Orificios Naturales , Procedimientos Quirúrgicos Robotizados , Animales , Femenino , Humanos , Histerectomía , Laparoscopía/métodos , Cirugía Endoscópica por Orificios Naturales/métodos , Procedimientos Quirúrgicos Robotizados/métodos , Salpingooforectomía , Porcinos
3.
Gastrointest Endosc ; 93(1): 193-200.e1, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32376335

RESUMEN

BACKGROUND AND AIMS: Meta-analysis shows that up to 26% of adenomas could be missed during colonoscopy. We investigated whether the use of artificial intelligence (AI)-assisted real-time detection could provide new insights into mechanisms underlying missed lesions during colonoscopy. METHODS: A validated real-time deep-learning AI model for the detection of colonic polyps was first tested in videos of tandem colonoscopy of the proximal colon for missed lesions. The real-time AI model was then prospectively validated in a total colonoscopy in which the endoscopist was blinded to real-time AI findings. Segmental unblinding of the AI findings were provided, and the colonic segment was then re-examined when missed lesions were detected by AI but not the endoscopist. All polyps were removed for histologic examination as the criterion standard. RESULTS: Sixty-five videos of tandem examination of the proximal colon were reviewed by AI. AI detected 79.1% (19/24) of missed proximal adenomas in the video of the first-pass examination. In 52 prospective colonoscopies, real-time AI detection detected at least 1 missed adenoma in 14 patients (26.9%) and increased the total number of adenomas detected by 23.6%. Multivariable analysis showed that a missed adenoma(s) was more likely when there were multiple polyps (adjusted odds ratio, 1.05; 95% confidence interval, 1.02-1.09; P < .0001) or colonoscopy was performed by less-experienced endoscopists (adjusted odds ratio, 1.30; 95% confidence interval, 1.05-1.62; P = .02). CONCLUSIONS: Our findings provide new insights on the prominent role of human factors, including inexperience and distraction, on missed colonic lesions. With the use of real-time AI assistance, up to 80% of missed adenomas could be prevented. (Clinical trial registration number: NCT04227795.).


Asunto(s)
Adenoma , Neoplasias del Colon , Pólipos del Colon , Adenoma/diagnóstico por imagen , Inteligencia Artificial , Neoplasias del Colon/diagnóstico por imagen , Pólipos del Colon/diagnóstico por imagen , Colonoscopía , Humanos , Estudios Prospectivos
4.
Surg Innov ; 26(4): 436-441, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30755092

RESUMEN

Background. With increasing experience and technological advancement in surgical instruments, surgeons have explored the feasibility of single-incision laparoscopic surgery and natural orifice transluminal endoscopic surgery (NOTES). These techniques aim to further reduce surgical trauma, but are not popular due to their inherent pitfalls including clashing of instruments, lack of counter traction, lengthy operating time, and so on. A novel surgical robotic system was designed to overcome the limitations of the existing technologies. Animal trials were conducted to demonstrate its feasibility in performing robotic-assisted transrectal cholecystectomy in a porcine model. Method. The Novel surgical robotic system is a high dexterity, single access port surgical robotic system that enables surgeons to carry out single-port surgical procedure or NOTES. The proposed system's main features include the ability to perform intraabdominal and pelvic surgeries via natural orifices like the vagina or rectum. The system is equipped with multiple miniaturized (16 mm diameter) internally motorized robotic arms, each with a minimum of 7 degrees of freedom, a dual in vivo camera system, a cannula, and an external swivel system. Results. Robotic-assisted transrectal cholecystectomy was successfully performed in 3 adult male pigs. The estimated blood loss was <10 mL in all 3 cases. There were no intraoperative complications. The system provided good dexterity and clear vision. Conclusions. The trial demonstrated that the system can provide the surgeon a stable platform with adequate spacing for the transrectal insertion of robotic arms, 3-dimensional vision, and enhanced dexterity in performing NOTES cholecystectomy.


Asunto(s)
Colecistectomía/métodos , Cirugía Endoscópica por Orificios Naturales/métodos , Procedimientos Quirúrgicos Robotizados/métodos , Animales , Colecistectomía/instrumentación , Diseño de Equipo , Masculino , Modelos Animales , Cirugía Endoscópica por Orificios Naturales/instrumentación , Recto , Procedimientos Quirúrgicos Robotizados/instrumentación , Porcinos
5.
Endosc Int Open ; 9(4): E537-E542, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33816774

RESUMEN

Background and study aims Despite its widespread adoption, colonoscope still has its limitations. Advancement is often limited by the looping of colon. The isolation of SARS-CoV-2 in stool raises concern for the risk of disease transmission. A single-use robotic colonoscope, the NISInspire-C System, that features a balloon-suction anchorage mechanism was developed to address these. Methods The NISInspire-C balloons are designed to provide anchorage for straightening of the colon during advancement. Angulation at the bending section is tendon-wire driven by servo mechanisms integrated into a robotic control console. This was a pilot, prospective trial to evaluate the safety and feasibility of this system. Healthy volunteers underwent examination with the NISInspire-C, followed by the conventional colonoscope. The procedure time, cecal intubation rates (CIR), complications, and level of pain were measured. Results A total of 19 subjects underwent the examination. The cecal intubation rate was 89.5 % (17/19) and the overall time-to-cecum was 26.3 minutes (SD: 17.9 mins). There were no procedure-related complications. Polyps were detected in seven of 19 (36.8 %) subjects during the NISInspire-C procedure. Three more subjects were found to have adenomatous polyps with the conventional colonoscope. There was minimal variation in level of pain during the procedures with the two colonoscopes. Conclusion The single-use robotic colonoscope NISInspire-C is a safe and feasible alternative to the conventional colonoscope. Further technical refinement is needed to improve the CIR. This study was limited by its small sample size.

6.
J Urol ; 183(1): 370-7, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19914665

RESUMEN

PURPOSE: Patients with nocturnal enuresis may have small functional bladder capacity or altered bladder fullness sensation. We determined whether reducing bladder volume would affect the central inhibition of voiding that is normally present between birth and 2 weeks of life in neonatal rats. MATERIALS AND METHODS: One and 3-week-old Sprague-Dawley rats underwent 50% bladder volume reduction by suture closure of the bladder dome. T8-T10 spinal cord injury was done in select animals. Latency of the perigenital-bladder reflex, spontaneous voiding onset and body weight were measured. Cystometry using urethane anesthesia, and measurements of in vitro spontaneous and KCl evoked contractions were done. RESULTS: Bladder reduction surgery led to the immediate appearance of spontaneous voiding in 1-week-old rats. Cystometry at 2 weeks showed voiding contractions in rats with bladder reduction, which was abolished by acute T8-T10 spinalization. Voiding contractions were not seen in animals with sham surgery or concurrent T8-T10 spinalization and bladder reduction. The perigenital-bladder reflex, somatic growth, spontaneous bladder contractions and bladder contractility were not affected by bladder reduction. Bladder capacity at 9 weeks was significantly larger in animals that underwent bladder reduction at 1 week than in sham treated animals (540 vs 256 microl, p = 0.04) but not in animals that underwent bladder reduction at 3 weeks. CONCLUSIONS: Bladder reduction removes the central inhibition of spontaneous voiding in neonatal rats. This suggests that decreased neonatal bladder capacity may alter how the brain regulates the bladder.


Asunto(s)
Vejiga Urinaria/fisiología , Vejiga Urinaria/cirugía , Micción/fisiología , Animales , Animales Recién Nacidos , Femenino , Masculino , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
7.
J Urol ; 184(5): 2186-91, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20850835

RESUMEN

PURPOSE: Our previous results revealed a positive correlation between bladder dysfunction and cortical arousals in children with enuresis. This finding implied an interrelationship between bladder dysfunction and brainstem dysfunction. Thus, we used an animal model to characterize brainstem functional changes in response to altered bladder function. MATERIALS AND METHODS: Adult male New Zealand rabbits weighing 3.0 to 3.5 kg underwent surgical bladder volume reduction (12) or sham operation (12). We performed conventional fill cystometry and brainstem functional magnetic resonance imaging in each group 4 weeks postoperatively. During scanning bladder stimulation was provided by bladder filling up to 70% of maximum capacity. We then compared brainstem activation area(s). RESULTS: Results revealed voiding dysfunction in animals with altered bladder function. Bladder function was markedly altered in the reduced bladder volume vs the sham operated group, mainly as significantly increased maximum voiding detrusor pressure (mean ± 1 SD 24.4 ± 7.0 vs 0.16.5 ± 7.2 cm water, p <0.05) and markedly decreased cystometric bladder volume (mean 35.3 ± 8.2 vs 71.6 ± 12.9 ml, p <0.05). Functional magnetic resonance imaging results revealed activation of 2 brainstem regions, including in 1) the ventrolateral periaqueductal gray and 2) the dorsolateral pons, in response to bladder distention. Activation in the ventrolateral periaqueductal gray was significantly decreased in the reduced bladder vs the sham operated group with a corresponding decrease in signal size (25% vs 83.3%, signal size 0.7 ± 1.4 vs 3.3 ± 2.1 mm(2)). There was no significant difference in activation of the dorsolateral pons between the groups (83.3% vs 91.7%, signal size 3.7 ± 2.4 vs 0.4.7 ± 3.0 mm(2)). CONCLUSIONS: Functional derangement in brainstem micturition centers can be evoked by bladder dysfunction. In response to bladder dysfunction the ventrolateral periaqueductal gray shows deactivation during bladder distention, suggesting that it has an important role in bladder dysfunction biofeedback.


Asunto(s)
Tronco Encefálico/fisiopatología , Imagen por Resonancia Magnética , Vejiga Urinaria/fisiopatología , Animales , Masculino , Conejos , Vejiga Urinaria/cirugía
8.
Pediatr Res ; 67(4): 440-3, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20057338

RESUMEN

UNLABELLED: To evaluate bladder function in infants with antenatally diagnosed hydronephrosis (ANH) using dynamic ultrasound protocol. Forty consecutive male infants (mean, 0.25 y) with ANH and 33 age-matched normal controls (mean, 0.49 y) were recruited. Anteroposterior (AP) diameter of renal pelvis (RP) and hydronephrosis index [HI = anteroposterior diameter of RP of kidney divided by urinary bladder volume (BV)] were calculated. Maximum BV (MaxBV) was determined just before voiding. Residual volume (RV) and bladder wall thickness (BWT) were measured after spontaneous voiding. Thirty-one infants (77.5%) showed persistently dilated RP postnatally in which 12 (39%) showed significantly high HI. In general, ANH infants had smaller MaxBV (30.71 versus 52.45 mL), larger residual volume (2.47 versus 1.93 mL), and larger BWT (4.4 versus 3.7 mm) than normal (p < 0.05, Mann-Whitney test). Infants with abnormally high HI had significantly more disturbed bladder parameters [smaller MaxBV (23.33 versus 33.49 mL) and larger BWT (4.67 versus 3.79 mm)] than the normal HI group (p < 0.05, Mann-Whitney test). Abnormal functional bladder parameters were evident in ANH infants. We postulated that immature function in the pelviureteric junction was associated with bladder dysfunction in these infants. Dynamic ultrasound protocol might help to understand the underlying pathophysiology of urinary system in ANH infants. ABBREVIATIONS: :


Asunto(s)
Hidronefrosis/diagnóstico por imagen , Vejiga Urinaria/diagnóstico por imagen , Animales , Femenino , Humanos , Hidronefrosis/fisiopatología , Lactante , Recién Nacido , Masculino , Embarazo , Ultrasonografía , Vejiga Urinaria/anatomía & histología , Vejiga Urinaria/fisiología , Vejiga Urinaria/fisiopatología
9.
J Dig Dis ; 20(4): 196-205, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30834714

RESUMEN

Advances in the field of robotics have allowed modern technology to be integrated into medicine and that can minimize patients suffering from the side effects that are inherent to procedures for improving their quality of life. Conventional devices that are used for colonoscopies are rigid and require a high level of expertise from endoscopists to perform the procedure. Advances in robot-assisted colonoscopic systems now produce softer, more slender, automated designs that no longer require the operator to use forceful pushing to advance the colonoscope inside the colon, reducing risks to the patient of perforation and pain. It is challenging to reprocess these scopes for reuse as the materials used can be damaged during decontamination, leading to the possible risks of cross-infection by pathogenic microorganisms when reused by patients. An ideal solution is to eliminate these contamination risks to patients by adopting sterile, single-use scopes straight from the manufacturer's package to the patient. With this idea in mind, emerging developments that push the boundaries in this area will benefit patients and encourage the public to participate in and adhere better to colonoscopy screening to reduce the development of colorectal cancer. Thus, in light of these concerns and challenges, to encourage patients undergoing colorectal screening to comply with colonoscopy procedures that they are less invasive, changes in the design and materials are necessary. One of the more promising technological advances in this area is the advent of robotic colonoscopy.


Asunto(s)
Colonoscopía/métodos , Robótica/métodos , Neoplasias Colorrectales/diagnóstico , Detección Precoz del Cáncer , Humanos
10.
J Urol ; 180(4): 1543-50, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18710724

RESUMEN

PURPOSE: Congenital bladder anomalies are a major challenge to pediatric urologists. Understanding the mechanism of bladder development is crucial for advancing patient treatment. Current evidence suggests that Shh (R&D Systems) is an epithelial signal regulating bladder development, although the mechanism of the regulation is still unclear. We examined the regulation of bladder mesenchymal development. MATERIALS AND METHODS: Mutation analysis, immunohistochemistry, immunoblot, in situ hybridization, and primary cell culture and transfection were performed. The mesenchyma proximal to the epithelium was defined as the inner zone and that distal to the epithelium was defined as the outer zone. RESULTS: We found that the Shh transcriptional factor Gli2 and the Shh target gene Bmp4 (R&D Systems) were expressed in the inner mesenchymal zone of the bladder, where active cell proliferation was observed. In Gli2(-/-) bladder primary mesenchymal cell cultures transfection with adenoviruses expressing DeltaNGli2, a constitutionally active form of Gli2, up-regulated Bmp4 expression and promoted cell proliferation. In the outer mesenchymal zone, where Gli2 and Bmp4 expression was not detectable, smooth muscle alpha-actin was expressed. In Gli2(-/-) embryo bladders Bmp4 expression in the inner zone was lost and ectopic smooth muscle was detected in the inner mesenchymal zone. Exogenous Bmp4 (10 ng/ml) in primary smooth muscle cell culture repressed smooth muscle differentiation and repression was partially rescued by the Bmp4 antagonist Noggin (R&D Systems) (300 ng/ml). CONCLUSIONS: Our data suggests that the Shh transcriptional factor Gli2 regulates radial patterning of the bladder mesenchyma.


Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Proteínas Hedgehog/genética , Factores de Transcripción de Tipo Kruppel/genética , Mesodermo/patología , Vejiga Urinaria/embriología , Vejiga Urinaria/patología , Análisis de Varianza , Animales , Proliferación Celular , Modelos Animales de Enfermedad , Femenino , Proteínas Hedgehog/metabolismo , Immunoblotting , Inmunohistoquímica , Hibridación in Situ , Etiquetado Corte-Fin in Situ , Factores de Transcripción de Tipo Kruppel/metabolismo , Mesodermo/embriología , Ratones , Reacción en Cadena de la Polimerasa , Embarazo , Preñez , Probabilidad , ARN/análisis , Ratas , Sensibilidad y Especificidad , Transfección , Proteína Gli2 con Dedos de Zinc
11.
Helicobacter ; 13(3): 219-24, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18466397

RESUMEN

BACKGROUND: Data of Helicobacter pylori prevalence in children and its risk factors provide clues to the health authority to estimate burden of H. pylori-associated diseases usually encountered in adulthood and facilitate healthcare planning. MATERIALS AND METHODS: A cross-sectional population-based study was conducted in Chinese children in elementary and high schools. Schools were selected from all three major areas of Hong Kong. H. pylori infection was defined by a positive (13)C-urea breath test. Study subjects were stratified into six age groups for estimation of prevalence. Potential risk factors were analyzed from data of self-administered questionnaires. RESULTS: A total of 2480 children (aged 6-19, male: 47.3%) participated in the study. Overall, 324 (13.1%) were positive for H. pylori. There was no difference in prevalence between sexes, and no statistical trend in the prevalence across the six age groups. Multivariate logistic regression identified lack of formal education of mother (OR = 2.43, 95%CI 1.36-4.34), family history of gastric cancer (OR = 2.19, 95%CI 1.09-4.41), and household member > 5 (OR = 1.57, 95%CI 1.12-2.19) to be positively associated with H. pylori infection in our children. CONCLUSIONS: The H. pylori prevalence of Hong Kong children is comparable to the data of developed countries. The association with family history of gastric cancer justifies further study to investigate the cost-benefit of community screening program for such children to decrease the incidence of gastric cancer in adulthood.


Asunto(s)
Infecciones por Helicobacter/epidemiología , Helicobacter pylori , Niño , Estudios Transversales , Hong Kong , Humanos , Masculino , Prevalencia , Factores de Riesgo
12.
J Laparoendosc Adv Surg Tech A ; 18(2): 296-301, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18373462

RESUMEN

BACKGROUND: Sacrococcygeal teratoma (SCT) is one of the most common tumors encountered in the neonatal period. Traditionally, a large abdominal incision is required for the combined abdominal perineal approach for the complete resection of type II-IV tumors. In this paper, we report our experience of using the combined laparoscopic perineal approach in treating these tumors. METHODS: Between November 2000 and September 2004, 4 patients with SCT were treated by the combined approach. The operation was started with the laparoscopic mobilization of the pelvic part of the tumor, followed by the completion excision and tumor retrieval through the perineal route. RESULTS: The operation was successfully completed in all patients, with a mean operative time of 279 minutes. There was no complication related to the laparoscopic dissection. Postoperative recovery was uneventful in all patients, except in 1 with a minor wound problem. At a median follow-up of 46.5 months, there was no recurrence encountered in all these patients and the cosmetic result was excellent. Functional outcome was satisfactory, except in the patient with spinal metastases. CONCLUSION: The combined laparoscopic and perineal approach provides a safe, excellent access in removing type II-IV SCT in infants.


Asunto(s)
Laparoscopía , Neoplasias Pélvicas/cirugía , Región Sacrococcígea , Teratoma/cirugía , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Neoplasias Pélvicas/congénito , Perineo/cirugía , Teratoma/congénito
13.
Clin Perinatol ; 44(4): 835-849, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29127964

RESUMEN

Minimally invasive ureteral reimplantation is an attractive and useful tool in the armamentarium for the management of complicated vesicoureteral reflux (VUR). Subureteric dextranomer/hyaluronic acid injection, laparoscopic extravesical ureteric reimplantation and pneumovesicoscopic intravesical ureteral reimplantation with or without robotic assistance are established minimally invasive approaches to management of VUR. The high cost and the limited availability of robotics have restricted accessibility to these approaches. Laparoscopic and/or robotic ureteral reimplantation continues to evolve and will have a significant bearing on the management of complicated VUR in infants and young children.


Asunto(s)
Procedimientos de Cirugía Plástica/métodos , Procedimientos Quirúrgicos Robotizados/métodos , Uréter/cirugía , Infecciones Urinarias/prevención & control , Procedimientos Quirúrgicos Urológicos/métodos , Reflujo Vesicoureteral/cirugía , Preescolar , Dextranos/uso terapéutico , Humanos , Lactante , Recién Nacido , Inyecciones , Laparoscopía/métodos , Procedimientos Quirúrgicos Mínimamente Invasivos/métodos , Reimplantación/métodos
14.
Soft Robot ; 4(4): 324-337, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29251567

RESUMEN

Bioinspired robotic structures comprising soft actuation units have attracted increasing research interest. Taking advantage of its inherent compliance, soft robots can assure safe interaction with external environments, provided that precise and effective manipulation could be achieved. Endoscopy is a typical application. However, previous model-based control approaches often require simplified geometric assumptions on the soft manipulator, but which could be very inaccurate in the presence of unmodeled external interaction forces. In this study, we propose a generic control framework based on nonparametric and online, as well as local, training to learn the inverse model directly, without prior knowledge of the robot's structural parameters. Detailed experimental evaluation was conducted on a soft robot prototype with control redundancy, performing trajectory tracking in dynamically constrained environments. Advanced element formulation of finite element analysis is employed to initialize the control policy, hence eliminating the need for random exploration in the robot's workspace. The proposed control framework enabled a soft fluid-driven continuum robot to follow a 3D trajectory precisely, even under dynamic external disturbance. Such enhanced control accuracy and adaptability would facilitate effective endoscopic navigation in complex and changing environments.


Asunto(s)
Robótica , Endoscopía , Diseño de Equipo , Análisis de Elementos Finitos
15.
J Laparoendosc Adv Surg Tech A ; 16(3): 325-7, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16796452

RESUMEN

Despite the advances in minimally invasive surgery in children, considerable concern exists about employing such techniques in oncologic cases. We report our experience with a 4-year-old girl with a symptomatic tumor in the liver. Contrast-enhanced computed tomography revealed a 3 x 4 cm lesion, confined to segments II and III. Tumor markers were negative and true-cut needle biopsy did not rule out malignancy. We performed a diagnostic laparoscopy using four 5-mm ports. Since the tumor did not cause any alterations of the liver surface, a 5-mm flexible endoscopic ultrasound probe (5 MHz) was applied to reveal the extent of the tumor. Parenchymal dissection was performed with a radiofrequency probe, and the LigaSure device was used to seal larger vessels and bile ducts. The tumor was resected completely and removed in a specimen bag via the umbilical incision. Histology revealed fibrous nodular hyperplasia. The postoperative course was uneventful and the girl was discharged on postoperative day 5. We conclude that laparoscopic resection of confined liver lesions is feasible in children, employing standard principles of oncologic surgery and safety.


Asunto(s)
Hiperplasia Nodular Focal/diagnóstico , Hiperplasia Nodular Focal/cirugía , Laparoscopía/métodos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/cirugía , Preescolar , Medios de Contraste , Femenino , Hiperplasia Nodular Focal/diagnóstico por imagen , Humanos , Neoplasias Hepáticas/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
16.
Medicine (Baltimore) ; 95(14): e3250, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27057869

RESUMEN

Due to the neurotoxicity effects of general anesthesia (GA) and sedatives found in animal studies, there is a general recommendation to avoid nonurgent surgical procedures requiring anesthesia in children younger than 3 years of age. The aim of this study was to determine the incidence of anesthesia-related postoperative cognitive dysfunction (POCD) on the first day (Day 1) and at 6 weeks after elective noncardiac surgery in school-age children.This was a prospective cohort study of 118 children undergoing GA and 126 age-matched controls of school children aged 5 to 12 years. All children were given a panel of 4 neuropsychological assessments (Hong Kong List Learning for verbal memory, Visual Matching for processing speed, Visual Memory, and General Comprehension Skill from the Hong Kong Wechsler Intelligence Scale for Children). The primary outcome was the incidence of POCD on Day 1 and at 6 weeks after surgery. POCD was defined as when at least 2 of the 4 cognitive function tests showed individual Z-scores ≤-1.96 or a combined Z-score ≤-1.96.Using the combined Z-score definition, the incidence of POCD in the GA group on Day 1 and at 6 weeks were 5.1% (95% confidence interval [CI]: 2.1-10.3) and 3.4% (95% CI: 1.1-8.0), respectively. No POCD was found using the other definition. The incidences of decline and improvement in neuropsychological tests were similar between groups over time except for a higher risk in visual matching impairment in the anesthesia group (11.9%) versus control group (1.6%) on Day 1 (P < 0.01). The adjusted relative risk ratio of postoperative cognitive decline to improvement between groups on Day 1 and at 6 weeks were 0.85 (95% CI: 0.10-7.05) and 0.45 (95% CI: 0.04-4.84), respectively. The observed risk of POCD is assumed to apply to current drugs and techniques used in GA.In conclusion, the incidence of POCD was low. GA was associated with a transient effect on visual matching. When using the widely accepted Z-score definitions and relative risk ratio methodology, we found no anesthesia-related POCD per se in school-age children.


Asunto(s)
Anestesia General/efectos adversos , Trastornos del Conocimiento/etiología , Complicaciones Posoperatorias/etiología , Niño , Trastornos del Conocimiento/epidemiología , Estudios de Cohortes , Femenino , Humanos , Incidencia , Masculino , Complicaciones Posoperatorias/epidemiología , Factores de Tiempo
17.
Ultrasound Med Biol ; 28(7): 865-72, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12208327

RESUMEN

The nature of the action of the vesicoureteric junction (VUJ) in humans is still controversial. We were interested in the reasons why the jet consists of several peaks. We hypothesised that the modification of the jet into a variable number of peaks is the result of an active sphincter mechanism at the VUJ. A total of 1,010 subjects of all ages and both genders were recruited into this study. The Doppler waveform of the jet was recorded bilaterally. We could identify six basic patterns of ureteric jet according to the number of peaks: monophasic, biphasic, triphasic, polyphasic (four or more peaks), square and continuous. By analysing the duration, maximum peak velocity and initial slope of the first four patterns, a mechanism of action of an active VUJ sphincter could be postulated. Furthermore, the basic patterns could be assigned to three modes of ureteric actions: the square and continuous are only seen during diuretic stress; the biphasic, triphasic and polyphasic patterns are variations of the adult physiological steady-state mode, and the monophasic is distinctly different and represents the immature mode.


Asunto(s)
Ultrasonografía Doppler en Color , Uréter/diagnóstico por imagen , Adolescente , Adulto , Análisis de Varianza , Niño , Preescolar , Femenino , Humanos , Masculino , Estadísticas no Paramétricas , Micción/fisiología , Urodinámica/fisiología
18.
Ultrasound Med Biol ; 28(7): 873-8, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12208328

RESUMEN

The Doppler waveform of the ureteric jet is the result of modification of ureteric peristalsis by an active sphincteric mechanism of the vesicoureteric junction (VUJ). The monophasic pattern is associated with immaturity. This study set out to see the correlation between this immature pattern with urinary tract infection (UTI) and vesicoureteric reflux (VUR) in children. Ureteric jets of 241 healthy children and 98 children with UTI were studied. The monophasic pattern was found in 29% of healthy children overall, but varied greatly according to age. The monophasic pattern was virtually universal in the first 6 months of life, dropping to below 15% in late childhood. This immature pattern was more commonly seen in the UTI (73.5%) and VUR (90.5%) groups than in the healthy controls. The difference was statistically significant (p = 0.0005 for both). The persistence of this immature pattern was highly associated with UTI and VUR.


Asunto(s)
Ultrasonografía Doppler , Uréter/diagnóstico por imagen , Infecciones Urinarias/diagnóstico por imagen , Reflujo Vesicoureteral/diagnóstico por imagen , Adolescente , Distribución de Chi-Cuadrado , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Curva ROC , Sensibilidad y Especificidad , Infecciones Urinarias/fisiopatología , Urodinámica , Reflujo Vesicoureteral/fisiopatología
19.
Ultrasound Med Biol ; 29(9): 1237-40, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-14553798

RESUMEN

We have already suggested that there is an active bimodal sphincteric mechanism in the human vesicoureteral junction (VUJ). This mechanism is affected by immaturity, hormonal effects and surgical ablation. This study set out to investigate the effects of anaesthesia on this mechanism. A total of 16 children undergoing surgery were recruited. They were well hydrated. The ureteric jets before and after anaesthesia were recorded using the colour and pulse wave Doppler. Of the total, 14 children showed mature (complex pattern) and two showed immature (monophasic pattern) waveforms before surgery. After anaesthesia, all showed the monophasic waveform (p=0.01). Thus, the sphincteric action of VUJ as manifest by the complexity of the ureteric jet was modified by anaesthesia by loss of the complex pattern. This supports the hypothesis that the complex pattern is a neural modulation of the simpler myogenic mechanism that produces the monophasic jet.


Asunto(s)
Anestésicos/farmacología , Uréter/efectos de los fármacos , Uréter/diagnóstico por imagen , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Ultrasonografía Doppler en Color/métodos , Ultrasonografía Doppler de Pulso/métodos , Uréter/fisiología , Urodinámica/efectos de los fármacos
20.
Chin J Integr Med ; 17(7): 548-55, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21725883

RESUMEN

The surgeon aims at a direct, complete removal of the pathology. In spite of the modern advancements of imaging facilities and precision instrumentations, unsatisfactory results and recurrences are not uncommon. This paper provides a general review of the four specific areas in surgery that would benefit from Chinese medicine. Extensive searches were made on four surgical areas based on available English language journals, viz. low-back pain, chronic ulcers, renal calculus, and enuresis in children, in the past 10 years. The quoted communications are mainly related to clinical evidences, while a smaller number of crucial laboratory reports are also included. Low-back pain, a most frequent orthopaedic problem, would benefit from acupuncture treatment. Chronic leg ulcers could achieve better results of healing using herbal supplements. Problems of renal stones, besides the conventional methods of removal, could be further supplemented with herbal drinks that aim at prevention of recurrences. Enuresis in children, an untreatable common condition, may respond well to acupuncture. Surgeons should keep an open mind. In case of difficulties, they could seriously consider options of traditional treatment.


Asunto(s)
Cirugía General , Medicina Tradicional China , Médicos , Terapia Combinada , Humanos
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