Discover the most talked about and latest scientific content & concepts.

Concept: Dilation


Balloon dilation may offer a more expedient and cost-effective treatment method compared with traditional endoscopic sinus surgery for chronic maxillary atelectasis. We sought to demonstrate the feasibility of balloon dilation of the maxillary os as a treatment modality for patients with chronic maxillary atelectasis by investigating the short-term outcomes in a retrospective case series of 4 patients representing 5 sinuses treated between 2011 and 2013. All sinuses were successfully balloon dilated without complications. Follow-up ranged from 1 week to 4 months. Aeration of the treated sinuses without restenosis was confirmed by postoperative endoscopy, sinus computed tomography, or both. All patients reported subjective symptomatic improvement. Balloon dilation of the maxillary os may be a feasible treatment option for maxillary sinus atelectasis. Longer follow-up and a larger study sample will be needed to validate the safety of this technique and determine the rate of restenosis.

Concepts: Sinusitis, Retrospective, Maxillary sinus, Endoscopy, Case series, Dilation, Cervical dilation


BACKGROUND: Endosonography (EUS)-guided transmural pseudocyst drainage is a multistep procedure currently performed with different “off-the-shelf” accessories developed for other applications. Multiple device exchanges over-the-wire is time consuming and risks loss of wire access. This report describes the technical feasibility and outcomes for EUS-guided drainage of pancreatic fluid collections using a novel exchange-free device developed for translumenal therapy. METHODS: Between April and November 2010, 14 patients (9 men; mean age, 49.9 years) with pancreatic fluid collection (mean size, 102 mm) underwent 16 EUS-guided drainage procedures using the exchange-free access device at a single tertiary care center. The trocar of the exchange-free device was used to gain pseudocyst access. The dual-balloon catheter then was advanced over the trocar, followed by inflation of the (first) anchor balloon. Cyst contents were sampled, and contrast was injected to define the pseudocyst anatomy. The first guidewire was inserted into the cyst cavity. The cystenterostomy tract was dilated to 10 mm with the (second) dilation balloon, followed by a second guidewire insertion. The exchange-free access device was removed, leaving the two guidewires in place for two double-pigtail stents. RESULTS: The procedure was technically successful for all the patients. No acute procedure-related complications occurred. Late complications included a symptomatic leak in a patient who underwent drainage of a pancreatic uncinate pseudocyst from the second duodenum, a self-limited transfusion-dependent bleed after transbulbar drainage, and symptomatic pseudocyst infection. CONCLUSION: Pseudocyst access, cystenterostomy tract dilation, and placement of two guidewires for dual stent drainage are technically feasible using an exchange-free access device. The device has the potential to standardize, simplify, and streamline EUS-guided pseudocyst drainage with a single instrument. Comparative studies with alternative tools and methods for pseudocyst drainage are warranted.

Concepts: Stent, Tertiary referral hospital, Sebaceous cyst, Cyst, Pancreatic pseudocyst, Pseudocyst, Dilation


The aim of this prospective study was to characterise patient characteristics and the histories of cats with acquired nasopharyngeal stenosis (ANS), and to describe the use of a removable silicone stent for treatment. ANS was diagnosed in 15 cats with clinical signs present for a median of 4 months. Clinical signs included stertor and inspiratory difficulty, nasal discharge, sneezing, dysphagia, regurgitation, vomiting and anorexia. Radiographs revealed a dorsal deviation or deformation of the caudal part of the soft palate in 10 of the cats, a soft tissue density across the cranial nasopharynx in four and no abnormality in one. The stenosis was initially dilated with a Kelly forceps in 10 of the cats and by balloon dilatation in five. A segment of a 24 Fr silicone thoracic catheter was used for the stent in five cats; in the other 10 cats a segment of a 28 Fr catheter was used. The stent was removed after 3 weeks in 12 cats and after 4 weeks in the other three. Endoscopy revealed an adequate nasopharyngeal diameter in all of the cats. At both 3 and 10 months after surgery the response was considered to be satisfactory, with complete resolution of clinical signs in 14 cats and improvement in the remaining cat. The treatment of ANS by stenosis dilatation followed by temporary stenting with a silicone stent is a rapid, safe, economical and effective procedure.

Concepts: Stent, Soft tissue, Nasopharynx, Soft palate, Palate, Hard palate, Levator veli palatini, Dilation


Dilated cardiomyopathy is characterised by dilation and impaired systolic function. We present the case of a child with dilated cardiomyopathy caused by a 624 kb duplication of 6q22.31, which includes the phospholamban gene. The patient also has failure to thrive and developmental delay due to complex cytogenetic abnormalities including a 5p15 deletion associated with Cri du Chat and an 11p15 duplication associated with Russell-Silver syndrome.

Concepts: DNA, Genetics, Chromosome, Cytogenetics, Down syndrome, Genetic disorders, Dilation


New labor curves have challenged the traditional understanding of the general pattern of dilation and descent in labor. They also revealed wide variation in the time to advance in dilation. An interval of arrest such as 4 hours did not fall beyond normal limits until dilation had reached 6 cm. Thus the ACOG/SMFM first stage arrest criteria, based in part on these findings, are applicable only in late labor. The wide range of time to dilate is unavoidable because cervical dilation has neither a precise nor direct relationship to time. Newer statistical techniques (multifactorial models) can improve precision by incorporating several factors that are directly related to labor progress. At each examination the calculations adapt to the mother’s current labor conditions. They produce a quantitative assessment expressed in percentiles. Low percentiles indicate potentially problematic labor progression.

Concepts: Scientific method, Statistics, Sociology, Accuracy and precision, Quantitative research, Dilation, Cervical dilation


We have all experienced that time seems stretched during unpleasant situations. While there is evidence of subjective time overestimation when perceiving external unpleasant stimuli, no study has measured the dilation of time when individuals experience an unpleasant situation in their own body. Here we measured the time dilation induced by a painful homeostatic deviance using temporal bisection task. We show that being in pain leads to an expansion of subjective time whereby a stronger increase in pain perception relative to non-painful stimulation leads to a stronger time-estimate distortion. Neurophysiological studies suggest that time estimation and the perception of self might share a common neural substrate. We propose that, along with bodily arousal and attentional capture, the enhancement of self-awareness may be critical to support dilated subjective time when experiencing pain. As other homeostatic deviances, pain may induce a focus on ourselves contributing to the impression that “time stands still”.

Concepts: Time, Psychology, Perception, Pain, Experience, Unsolved problems in neuroscience, Suffering, Dilation


The purpose is to use laws of physics to elucidate the mechanisms behind capillary non-perfusion in diabetic retinopathy. In diabetic retinopathy, loss of pericytes weakens capillary walls and the vessel dilates. A dilated capillary has reduced resistance to flow, therefore increased flow in that vessel and decreased in adjoining capillaries. A preferential shunt vessel is thus formed from the dilated capillary and the adjacent capillaries become non-perfused. We apply the laws of Laplace and Hagen-Poiseuille to better understand the phenomena that lead to capillary non-perfusion. These laws of physics can give a foundation for physical or mathematical models to further elucidate this field of study. The law of Laplace predicts that a weaker vessel wall will dilate, assuming constant transmural pressure. The Hagen-Poiseuille equation for flow and the Ostwald-de Waele relationship for viscosity predict that a dilated vessel will receive a higher portion of the fluid flow than the adjoining capillaries. Viscosity will decrease in the dilated vessel, furthering the imbalance and resulting in a patch of non-perfused capillaries next to the dilated ‘preferential’ shunt vessel. Physical principles support or inspire novel hypotheses to explain poorly understood phenomena in ophthalmology. This thesis of pericyte death and capillary remodelling, which was first proposed by Cogan and Kuwabara, already agrees with histological and angiographical observations in diabetic retinopathy. We have shown that it is also supported by classical laws of physics.Eye advance online publication, 19 January 2018; doi:10.1038/eye.2017.313.

Concepts: Scientific method, Understanding, Physics, Fluid dynamics, Capillary, Fluid mechanics, Fluid, Dilation


In patients with ileus with dilated intestine in imaging studies, endoscopic decompression appears a feasible option. However, its use is often uncritical and without scientific evidence. Before considering endoscopic intervention, CT-imaging should differentiate between mechanical obstruction and paralytic ileus/intestinal pseudo-obstruction. Tumor diagnosis and localisation are essential because the latter determines the choice of the decompression procedure. Coecal dilatation of more than 12 cm indicates an increased risk of perforation. In patients with toxic megacolon, dilation of the transverse colon to more than 6 cm is considered critical without much prospective evidence. Endoscopic decompression has a high complication rate and should be performed electively, and not as an emergency procedure, whenever possible. The use of CO2 insufflation rather than ambient air is strongly recommended, as is the availability of fluoroscopy. Prior trans-nasal or oral decompression-tube placement is routinely performed, and tracheobronchial intubation frequently required. In over 90 % of patients with pseudo-obstruction, conservative treatment is successful within 24 to 48 hours, and endoscopic decompression is, therefore, unnecessary. Placement of self-expanding metal stents to decompress a tumor stenosis is considered mostly for the left colon and rectum and burdened with significant risks of perforation and stent migration. Stent impact on oncological outcome is controversial because of possible tumor cell mobilization and increased postoperative cancer recurrence rates. Surgery, as primary intervention, achieves its objective in most cases. Decompression effect by endoscopic suctioning of gas and intestinal fluid is usually transient so that it is combined with transrectal decompression tubes insertion. This paper reviews the advantages and flaws of various decompression procedures in different clinical settings.

Concepts: Cancer, Oncology, Ulcerative colitis, Gastroenterology, Bronchoscopy, Decompression sickness, Dilation


Patients presenting with pathologic nipple discharge (PND) often pose a diagnostic and therapeutic challenge. We used ultrasound to identify focal ductal dilatation-hypothesized to be a radiographic manifestation of the causative lesion-in patients with PND and no relevant clinical or radiographic findings. Twenty-two excisions guided by ultrasound wire localization of focal duct dilation were performed. Surgical pathology revealed papilloma in 20 cases (91%); atypia or carcinoma was detected in 7 cases (32%). The ultrasound finding of focal duct dilatation enables excision of otherwise occult though clinically significant lesions and is worthy of further study.

Concepts: Cancer, Pathology, Hospital, Surgery, Anatomical pathology, Clinical death, Excision, Dilation


Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., “napkin-ring” formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a “napkin-ring” configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to better understand the response to attempted TSF for newly developed stents as well as those currently in use.

Concepts: In vivo, Stent, Restenosis, Coronary stent, Bare-metal stent, Dilation