Peroral endoscopic myotomy assisted with an elastic ring for achalasia with obvious submucosal fibrosis:A case report

BACKGROUND Peroral endoscopic myotomy(POEM)is an established treatment option for esophageal achalasia.However,technical challenges and failures exist.Submucosal fibrosis is a rare cause of aborted POEM procedures.CASE SUMMARY We performed POEM with an elastic ring for achalasia with obvious submucosal fibrosis.The short-term outcome was excellent,surgery time was significantly shorter,and success rate was higher with POEM for achalasia with obvious submucosal fibrosis.CONCLUSION POEM performed with an elastic ring is a feasible and effective endoscopic treatment modality for achalasia with obvious submucosal fibrosis.

Gastric ulcer treated using an elastic traction ring combined with clip: A case report

BACKGROUND There is a high annual incidence of acute,nonvariceal upper gastrointestinal bleeding in Chinese adults.Early endoscopic intervention can reduce rates of rebleeding,surgery,and mortality.The metal clip is the most common method for establishing homeostasis;however,it possesses several limitations.In patients with bleeding secondary to large gastric ulcers,the clip will often fail to stop the bleeding.This article highlights the use of an elastic traction ring as a novel hemostatic method for patients with upper gastrointestinal bleeding.CASE SUMMARY An elderly male presented to the emergency room with complaints of hematemesis and melena.Endoscopic examination revealed an ulcer(Forrest IIa)in the lesser curvature of the gastric antrum.Six tissue clips and one elastic traction ring were inserted into the stomach cavity to suture the ulcer.The patient recovered quickly without postoperative gastrointestinal bleeding.Two months later,the patient's ulcer was significantly healed.CONCLUSION To our best knowledge,this is the first report to demonstrate the safety and efficacy of elastic traction rings for upper gastrointestinal bleeding.Elastic traction rings should be considered a routine therapeutic modality for patients with upper gastrointestinal bleeds.

Pressure performance for a thin-walled ring and turbulent-jet orifice modeled elastic squeeze film damper

This paper explores an analytical model for Elastic Ring Squeeze Film Damper(ERSFD) with thin-walled ring and turbulent-jet orifices, and uncovers its Oil Film Pressure Performance(OFPP). Firstly, the ring deformation is addressed by using the Fourier series expansion approach and the orifice outflow rate is characterized with the Prandtl boundary layer theory. Secondly, applying finite difference scheme, the influence of elastic ring flexibility, orifice diameter, and attitude angle on the OFPP is analyzed. Finally, Outer chamber pressure was measured experimentally at different rotor speeds. The results indicate that the outer chamber pressure coats an individual load-carrying region and spreads symmetrically pertaining to the attitude angle. Its amplitude drops as the elastic ring flexibility decreases but boosts with the reduction of the orifice diameter.For inner chamber pressure, the orifice diameter effects a similar trend to the outer cavity, but exhibits more stable distribution regarding the attitude angle. Minimizing the elastic ring flexibility causes an increase in amplitude. The model is validated by the test results giving that the outer chamber pressure shifts synchronously and periodically with the variation of the attitude angle,while the pressure amplitude increases slightly at higher rotor speeds.

ELASTIC CALCULATION OF STRESSES IN RINGS USING AIRY STRESS FUNCTION

Stress calculation formulae for a ring have been obtained by using Airy stress function of the plane strain field with the decomposition of the solutions for normal stresses of Airy biharmonic equation into two parts when it is loaded under two opposite inside forces along a diameter. One part should fulfill a constraint condition about normal stress distribution along the circumference at an energy valley to do the minimum work. Other part is a stress residue constant. In order to verify these formulae and the computed results, the computed contour lines of equi-maximal shear stresses were plotted and quite compared with that of photo-elasticity test results. This constraint condition about normal stress distribution along circumference is confirmed by using Greens’ theorem. An additional compression exists along the circumference of the loaded ring, explaining the divorcement and displacement of singularity points at inner and outer boundaries.