Dear Editor,Ocular decompression retinopathy(ODR),which manifests as diffuse retinal hemorrhage occurring abruptly in multiple locations,including the subretinal,intraretinal,and preretinal spaces,is a rare complicati...Dear Editor,Ocular decompression retinopathy(ODR),which manifests as diffuse retinal hemorrhage occurring abruptly in multiple locations,including the subretinal,intraretinal,and preretinal spaces,is a rare complication after glaucoma surgery and is caused by sudden,iatrogenic lowering of intraocular pressure(IOP).Implicated procedures include glaucoma drainage implantation,trabeculectomy,iridotomy,and even cataract surgery[1].One report described a case of ocular decompression management following uncomplicated cataract surgery with no posterior capsular rupture or other intraoperative complications[2].Here,we report a rare case of ODR triggered by phacoemulsification and the use of systemic chemotherapeutic drugs in a patient with primary acute angleclosure glaucoma(PACG).The case not only improves our understanding of potential side effects of chemotherapeutic drugs on ophthalmic surgery but may also serve as a reference for clinicians in the management of patients with glaucoma with similar medical histories.展开更多
Dear Editor,We present the first time,a case of a patient developed cerebrospinal fluid(CSF)leak and pneumocranium following optic canal decompression(OCD).INTRODUCTION Indirect traumatic optic neuropathy(ITON)impairs...Dear Editor,We present the first time,a case of a patient developed cerebrospinal fluid(CSF)leak and pneumocranium following optic canal decompression(OCD).INTRODUCTION Indirect traumatic optic neuropathy(ITON)impairs visual functions and quality of life.Endoscopic transnasal optic canal decompression(ETOCD)is one of the standard treatment strategies for the ITON.During the ETOCD,the optic nerve sheath are usually incised for sufficient decompression of optic nerve after removal of optic canal,which is associated with complications like CSF leakage,ophthalmic artery injury,and optic nerve injury[1].Generally,the mild CSF leak is common and can heal spontaneously using conventional treatment,the severe CSF leak requires surgical repair[2].展开更多
Intra-abdominal hypertension(IAH)and abdominal compartment syndrome(ACS)play a pivotal role in the pathophysiology of severe acute pancreatitis(SAP)and contribute to new-onset and persistent organ failure.The optimal ...Intra-abdominal hypertension(IAH)and abdominal compartment syndrome(ACS)play a pivotal role in the pathophysiology of severe acute pancreatitis(SAP)and contribute to new-onset and persistent organ failure.The optimal management of ACS involves a multi-disciplinary approach,from its early recognition to measures aiming at an urgent reduction of intra-abdominal pressure(IAP).A targeted literature search from January 1,2000,to November 30,2022,revealed 20 studies and data was analyzed on the type and country of the study,patient demographics,IAP,type and timing of surgical procedure performed,post-operative wound management,and outcomes of patients with ACS.There was no randomized controlled trial published on the topic.Decom-pressive laparotomy is effective in rapidly reducing IAP(standardized mean difference=2.68,95%confidence interval:1.19-1.47,P<0.001;4 studies).The morbidity and complications of an open abdomen after decompressive laparotomy should be weighed against the inadequately treated but,potentially lethal ACS.Disease-specific patient selection and the role of less-invasive decompressive measures,like subcutaneous linea alba fasciotomy or component separation techniques,is lacking in the 2013 consensus management guidelines by the Abdominal Compartment Society on IAH and ACS.This narrative review focuses on the current evidence regarding surgical decompression techniques for managing ACS in patients with SAP.However,there is a lack of high-quality evidence on patient selection,timing,and modality of surgical decompression.Large prospective trials are needed to identify triggers and effective and safe surgical decompression methods in SAP patients with ACS.展开更多
BACKGROUND Whether hyperbaric oxygen therapy(HBOT)can cause paradoxical herniation is still unclear.CASE SUMMARY A 65-year-old patient who was comatose due to brain trauma underwent decompressive craniotomy and gradua...BACKGROUND Whether hyperbaric oxygen therapy(HBOT)can cause paradoxical herniation is still unclear.CASE SUMMARY A 65-year-old patient who was comatose due to brain trauma underwent decompressive craniotomy and gradually regained consciousness after surgery.HBOT was administered 22 d after surgery due to speech impairment.Paradoxical herniation appeared on the second day after treatment,and the patient’s condition worsened after receiving mannitol treatment at the rehabilitation hospital.After timely skull repair,the paradoxical herniation was resolved,and the patient regained consciousness and had a good recovery as observed at the follow-up visit.CONCLUSION Paradoxical herniation is rare and may be caused by HBOT.However,the underlying mechanism is unknown,and the understanding of this phenomenon is insufficient.The use of mannitol may worsen this condition.Timely skull repair can treat paradoxical herniation and prevent serious complications.展开更多
Severe acute cholangitis(AC)exacerbates the risk of death because of the rapid progression of the disease.The optimal timing of biliary decompression(BD)as a necessary intervention in patients with severe AC is contro...Severe acute cholangitis(AC)exacerbates the risk of death because of the rapid progression of the disease.The optimal timing of biliary decompression(BD)as a necessary intervention in patients with severe AC is controversial.A recently report titled“Timing of endoscopic retrograde cholangiopancreatography in the treatment of acute cholangitis of different severity”in the World Journal of Gastroenterology that the optimal time of endoscopic retrograde cholangiopancreatography for treating patients with severe AC is≤48 but not≤24 h,providing clinical evidence for selecting the optimal time for implementation of BD.Here,we discuss the controversy over the optimal timing of BD for AC based on guidelines and clinical evidence,and consider that more high-level clinical researches are urgent needed to benefit the management of patients with different severity of AC.展开更多
Background: For decades, traditional open surgical techniques were used to treat lumbar disc herniation and lumbar canal stenosis (LCS). However, seeking for better outcomes for patients and avoiding extensive bony lo...Background: For decades, traditional open surgical techniques were used to treat lumbar disc herniation and lumbar canal stenosis (LCS). However, seeking for better outcomes for patients and avoiding extensive bony loss with its sequences had raised minimally invasive technique for treating these disorders as an alternative surgery. Methods: This is a retrospective study in which 54 patients of LCS were operated upon via unilateral minimally invasive technique to decompress the canal in a 360 degrees fashion through laminotomy, deroofing of opposite laminar side, sublaminar ligamintectomy, bilateral foraminotomies and discectomy. We used VAS scores and ODI to assess clinical outcomes with a period of one year follow-up. Results: Our results demonstrated that minimally invasive techniques for treating these disorders are effective procedures. Minimally invasive 360 degrees decompression for treating LCS had better outcomes regarding postoperative back pain, smaller incisions, less bony loss and early ambulation. Conclusion: Minimally invasive techniques for treating lumbar canal stenosis of different causes could be considered a better option instead of traditional full laminectomy with better outcomes as regards respecting the anatomical layers such as posterior spinal integrity and musculature, postoperative pain, accompanied with less blood loss, shorter hospital stays, and shorter recovery periods.展开更多
AIM:To evaluate the predictive value of superficial retinal capillary plexus(SRCP)and radial peripapillary capillary(RPC)for visual field recovery after optic cross decompression and compare them with peripapillary ne...AIM:To evaluate the predictive value of superficial retinal capillary plexus(SRCP)and radial peripapillary capillary(RPC)for visual field recovery after optic cross decompression and compare them with peripapillary nerve fiber layer(pRNFL)and ganglion cell complex(GCC).METHODS:This prospective longitudinal observational study included patients with chiasmal compression due to sellar region mass scheduled for decompressive surgery.Generalized estimating equations were used to compare retinal vessel density and retinal layer thickness preand post-operatively and with healthy controls.Logistic regression models were used to assess the relationship between preoperative GCC,pRNFL,SRCP,and RPC parameters and visual field recovery after surgery.RESULTS:The study included 43 eyes of 24 patients and 48 eyes of 24 healthy controls.Preoperative RPC and SRCP vessel density and pRNFL and GCC thickness were lower than healthy controls and higher than postoperative values.The best predictive GCC and pRNFL models were based on the superior GCC[area under the curve(AUC)=0.866]and the tempo-inferior pRNFL(AUC=0.824),and the best predictive SRCP and RPC models were based on the nasal SRCP(AUC=0.718)and tempo-inferior RPC(AUC=0.825).There was no statistical difference in the predictive value of the superior GCC,tempo-inferior pRNFL,and tempo-inferior RPC(all P>0.05).CONCLUSION:Compression of the optic chiasm by tumors in the saddle area can reduce retinal thickness and blood perfusion.This reduction persists despite the recovery of the visual field after decompression surgery.GCC,pRNFL,and RPC can be used as sensitive predictors of visual field recovery after decompression surgery.展开更多
We suggest that during severe acute pancreatitis(SAP)with intra-abdominal hypertension,practitioners should consider decompressive laparotomy,even with intra-abdominal pressure(IAP)below 25 mmHg.Indeed,in this setting...We suggest that during severe acute pancreatitis(SAP)with intra-abdominal hypertension,practitioners should consider decompressive laparotomy,even with intra-abdominal pressure(IAP)below 25 mmHg.Indeed,in this setting,non-occlusive mesenteric ischemia(NOMI)may occur even with IAP below this cutoff and lead to transmural necrosis if abdominal perfusion pressure is not promptly restored.We report our experience of 18 critically ill patients with SAP having undergone decompressive laparotomy of which one third had NOMI while IAP was mostly below 25 mmHg.展开更多
Objective:To observe the effect of recombinant human bone morphogenetic protein 2/polylactide-co-glycolic acid(rhBMP-2/PLGA) with core decompression on repair of rabbit femoral head necrosis.Methods:Bilateral femoral ...Objective:To observe the effect of recombinant human bone morphogenetic protein 2/polylactide-co-glycolic acid(rhBMP-2/PLGA) with core decompression on repair of rabbit femoral head necrosis.Methods:Bilateral femoral head necrosis models of rabbit were established by steroid injection.A total of 48 rabbits(96 femoral head necrosis) were randomly divided into 4groups:Group A,control group with12 rabbits,24 femoral head necrosis;Group B,treated with rhBMP-2/PLCA implantation after core depression,with 12 rabbits,24 femoral head necrosis;Group C,treated with rhBMP-2 implantation after core depression,with 12 rabbits,24 femoral head necrosis;Croup D treated with core depression group without implantation,with 12 rabbits,24 femoral head necrosis.All animals were sacrificed after 12 weeks.The ability of repairing bone defect was evaluated by X-ray radiograph.Bone mineral density analysis of the defect regions were used to evaluate the level of ossification.The morphologic change and bone formation was assessed by HE staining.The angiogenesis was evaluated by VEGF immunohistochemistry.Results:The osteogenetic ability and quality of femoral head necrosis in group B were better than those of other groups after 12 weeks by X-ray radiograph and morphologic investigation.And the angiogenesis in group B was better than other groups.Group C had similar osteogenetic quality of femoral head necrosis and angiogenesis with group D.Conclusions:The treatment of rhBMP-2/PLCA implantation after core depression can promote the repair of rabbit femoral head necrosis.It is a promising and efficient synthetic bone material to treat the femoral head necrosis.展开更多
AIM: To report the effects of intravenous high-dose glucocorticoids(iv GC) and orbital decompression(OD) surgery for treatment of sight-threatening thyroid-associated ophthalmopathy(TAO).METHODS: A retrospective revie...AIM: To report the effects of intravenous high-dose glucocorticoids(iv GC) and orbital decompression(OD) surgery for treatment of sight-threatening thyroid-associated ophthalmopathy(TAO).METHODS: A retrospective review of medical records from patients with sight-threatening TAO [definite or highly suspected dysthyroid optic neuropathy(DON)] treated with iv GC(60 cases) and OD(25 cases) was conducted at the Zhongshan Ophthalmic Center between January 2001 and January 2009. Patients were initially treated with iv GC(iv GC group). If no significant improvement in visual function was obtained, they then received OD surgery(OD group). The pre-versus post-treatment efficacies of either iv GC or OD in these patients were assessed using several indices, including visual acuity, intraocular pressure, ocular alignment, ocular motility, and exophthalmos. RESULTS: Nighty-one eyes had definite DON while 79 were considered to have highly suspected DON. In the iv GC group, 51 individuals(85.0%) eventually demonstrated normal vision, while 10 patients(16.7%) demonstrated a reduction in deviation(P<0.01), and 35 cases(58.3%) showed slight improvements in ocular motility(P<0.01). In OD group, visual acuity improved in 24 cases(96.0%, P<0.01) and all patients showed varying reductions of exophthalmos(mean: 4.35±1.13 mm, P<0.01). Eight cases(32.0%) experienced an 8-15 PD reduction of deviation and ocular motility improved in 12 cases(48.0%), while 3 patients(12.0%) developed new-onset strabismus with diplopia post-surgically(P<0.01). Patients were followed up at an average of 1.55±1.07 y. CONCLUSION: Both iv GC and OD show good therapeutic efficacy in the treatment of sight-threatening TAO. Thepresence of extremely poor eyesight(≥0.5 log MAR) was corrected in some patients with iv GC alone, thus sparing these patients from subsequent OD surgery. In patients who were refractory to steroids, subsequent OD surgery often provided satisfactory outcomes, however, new-onset strabismus with diplopia was observed in 12.0% of these cases.展开更多
BACKGROUND:Excessive hepatocyte apoptosis and bile lakes in severe obstructive jaundice might impair liver functions.Although decompression of the bile duct has been reported to improve liver functions in animal studi...BACKGROUND:Excessive hepatocyte apoptosis and bile lakes in severe obstructive jaundice might impair liver functions.Although decompression of the bile duct has been reported to improve liver functions in animal studies,the mechanism of obstruction differs from that in humans.This study aimed to determine the profiles of hepatocyte apoptosis and bile lakes following bile duct decompression in patients with severe obstructive jaundice in the clinical setting.METHODS:We conducted a 'before and after study' on severe obstructive jaundice patients as a model of inhibition of the excessive process by bile duct decompression.Specimens of liver biopsies were taken before and after decompression of the bile duct and then stained by terminal deoxynucleotide transferase-mediated dUTP nick end-labeling(TUNEL) to identify hepatocyte apoptosis and by hematoxilin-eosin(HE) to identify bile lakes.All measurements were independently done by 2 observers.RESULTS:Twenty-one severe obstructive jaundice patients were included.In all patients,excessive hepatocyte apoptosis and bile lakes were apparent.After decompression,the hepatocyte apoptosis index decreased from 53.1(SD 105) to 11.7(SD 13.6)(P<0.05),and the bile lakes from 23.6(SD 14.8) to 10.9(SD 6.9)(P<0.05).CONCLUSION:Bile duct decompression improves hepatocyte apoptosis and bile lakes in cases of severe obstructive jaundice,similar to the findings in animal studies.展开更多
U-shaped sacral fractures are rare and often difficult to diagnose primarily due to the difficulty in obtaining adequate imaging and the severe associated injuries. These fractures are highly unstable and frequently c...U-shaped sacral fractures are rare and often difficult to diagnose primarily due to the difficulty in obtaining adequate imaging and the severe associated injuries. These fractures are highly unstable and frequently cause neurological deficits. The majority of surgeons have limited experience in management of U-shaped sacral fractures. No standard treatment protocol for U-shaped sacral fractures has been available till now. This study aimed to examine the management of U-shaped sacral fractures and the early outcomes. Clinical data of 15 consecutive patients with U-shaped sacral fracture who were admitted to our trauma center between 2009 and 2014 were retrospectively analyzed. Demographics, fracture classification, mechanism of injury and operative treatment and deformity angle were assessed. All the patients were treated with lumbopelvic fixation or (and) sacral decompression. EQ-5d score was applied to evaluate the patients' quality of life. Of the 15 consecutive patients with U-shaped sacral fracture, the mean age was 28.8 years (range: 15-55 years) at the time of injury. There were 6 females and 9 males. The mean follow- up time was 22.7 months (range: 9-47 months) and mean full weight-bearing time was 9.9 weeks (range: 8-14 weeks). Ten patients received lumbopelvic fixation and sacral decompression, one lombosacral fixation, and 4 merely sacral decompression due to delayed diagnosis or surgery. The post-operation deformity angle (mean 27.87°, and range: 8°-90°) of the sacrum was smaller than that pre-operation (mean 35.67; range: 15-90) with no significance difference noted. At the latest follow-up, all patients obtained neurological recovery with different extents. Visual analogue score (VAS) was reduced from preoperative 7.07 (range: 5-9) to postoperetive 1.93 (range: 1-3). All patients could walk without any aid after treatment. Eight patients were able to care for themselves and undertook some daily activities. Five patients had returned to work full time. In conclusion, lumbopelvic fixation is an effective method for stabilization of U-shaped sacral fractures with fewer complications developed. Effective reduction and firm fixation are the prerequisite of early mobilization and neurological recovery. Sacral decompression effectively promotes neurological recovery even in patients with old U-shaped sacral fractures.展开更多
AIM: To evaluate the long-term results of different orbital decompression techniques performed in patients with Graves' ophthalmopathy(GO).METHODS: Totally 170 cases with GO underwent orbital decompression betwee...AIM: To evaluate the long-term results of different orbital decompression techniques performed in patients with Graves' ophthalmopathy(GO).METHODS: Totally 170 cases with GO underwent orbital decompression between 1994 and 2014. Patients were divided into 4 groups as medial-inferior, mediallateral(balanced), medial-lateral-inferior, and lateral only according to the applied surgical technique. Surgical indications, regression degrees on Hertel exophthalmometer, new-onset diplopia in the primary gaze and new-onset gaze-evoked diplopia after surgery and visual acuity in cases with dysthyroid optic neuropathy(DON) were compared between different surgical techniques.RESULTS: The study included 248 eyes of 149 patients. The mean age for surgery was 42.3±13.2 y. DON was the surgical indication in 36.6% of cases, and three-wall decompression was the most preferred technique in these cases. All types of surgery significantly decrease the Hertel values(P〈0.005). Balanced medial-lateral, and only lateral wall decompression caused the lowest rate of postoperative new-onset diplopia in primary gaze. The improvement of visual acuity in patients with DON did not significantly differ between the groups(P=0.181). CONCLUSION: The study show that orbital decompression surgery has safe and effective long term results for functional and cosmetic rehabilitation of GO. It significantly reduces Hertel measurements in disfiguring proptosis and improves visual functions especially in DON cases.展开更多
AIM: To investigate a possible correlation between visual acuity(VA) prognosis and the presence at baseline of various orbital and ocular signs in patients affected by indirect traumatic optic neuropathy(ITON). M...AIM: To investigate a possible correlation between visual acuity(VA) prognosis and the presence at baseline of various orbital and ocular signs in patients affected by indirect traumatic optic neuropathy(ITON). METHODS: From July 1 st, 2012 to July 1 st, 2015, 224 adults diagnosed with ITON who underwent endoscopic transethmosphenoid optic canal decompression(ETOCD) were reviewed. Visual outcome before and after treatment were taken into comparison. RESULTS: Accompanied older in age, longer time to medical treatment and existence of optic canal fracture(OCF) were the independent predictors for poor postoperative VA and lower improvement degree of visual acuity(IDVA), while worse preoperative VA was predictive factor for poor postoperative VA only. Mean value of IDVA in patients with OCF was 0.19±0.30. Mean value of IDVA in patients without OCF was 0.29±0.35. IDVA in cases without OCF was significant higher than those with OCF(t=2.272, P〈0.05). CONCLUSION: Patients suffered from ITON without OCF before ETOCD have better surgical outcome than those with OCF. Older in age, longer time to medical treatment and existence of OCF are independent factors for poor VA prognosis and lower IDVA. Preoperative VA is independent factor for VA prognosis only.展开更多
Primary hemifacial spasm(HFS) is a disorder that causes frequent involuntary contractions in the muscles on one side of the face, due to a blood vessel compressing the nerve at its root exit zone(REZ) from the brainst...Primary hemifacial spasm(HFS) is a disorder that causes frequent involuntary contractions in the muscles on one side of the face, due to a blood vessel compressing the nerve at its root exit zone(REZ) from the brainstem. Numerous prospective and retrospective case series have confirmed the efficacy of microvascular decompression(MVD) of the facial nerve in patients with HFS. However, while MVD is effective, there are still significant postoperative complications. In this paper, recent technological advances related to MVD(such as lateral spread response,brainstem auditory evokes potential, three dimensional time of flight magnetic resonance angiography, intraoperative neuroendoscopy) are reviewed for the purposes of improving MVD treatment efficacy and reducing postoperative complications.展开更多
Purpose:To investigate the safety and feasibility of radical total gastrectomy without postoperative gastrointestinal decompression in elderly patients with gastric cancer.Methods:Elderly patients(65e80 years of age)h...Purpose:To investigate the safety and feasibility of radical total gastrectomy without postoperative gastrointestinal decompression in elderly patients with gastric cancer.Methods:Elderly patients(65e80 years of age)hospitalized with gastric cancer from May 2009 to August 2012 were selected to receive radical total gastrectomy with(controls,n=39)or without(n=37)postoperative gastrointestinal decompression.Postoperative recovery conditions and associated complications were observed and compared.Results:In the group without decompression,the first passage of flatus post-operation was significantly earlier,and scores of nausea,pharyngitis,insomnia,and postoperative ambulation limitation were significantly reduced compared to controls(all p<0.01).However,there were no differences in the degree of abdominal distension,time to first anal defecation,or incidence of postoperative complications between the groups.Conclusion:Gastrointestinal decompression is not necessary after total gastrectomy in elderly gastric cancer patients,and may improve patient comfort and recovery.展开更多
A variety of inlfammatory cytokines are involved in spinal cord injury and inlfuence the recov-ery of neuronal function. In the present study, we established a rat model of acute spinal cord injury by cerclage. The ce...A variety of inlfammatory cytokines are involved in spinal cord injury and inlfuence the recov-ery of neuronal function. In the present study, we established a rat model of acute spinal cord injury by cerclage. The cerclage suture was released 8 or 72 hours later, to simulate decompres-sion surgery. Neurological function was evaluated behaviorally for 3 weeks after surgery, and tumor necrosis factorα immunoreactivity and apoptosis were quantiifed in the region of injury. Rats that underwent decompression surgery had significantly weaker immunoreactivity of tumor necrosis factorα and signiifcantly fewer apoptotic cells, and showed faster improvement of locomotor function than animals in which decompression surgery was not performed. De-compression at 8 hours resulted in signiifcantly faster recovery than that at 72 hours. These data indicate that early decompression may improve neurological function after spinal cord injury by inhibiting the expression of tumor necrosis factorα.展开更多
BACKGROUND: The main clinical treatments for optic nerve injury are optic canal decompression and systemic administration of hormones, but both treatments have disadvantages. OBJECTIVE: To observe the pathological c...BACKGROUND: The main clinical treatments for optic nerve injury are optic canal decompression and systemic administration of hormones, but both treatments have disadvantages. OBJECTIVE: To observe the pathological changes in the retina and growth associated protein-43 (GAP-43) expression, to compare the treatment of optic canal decompression, hormones, and their combination with the intracanalicular optic nerve injury.DESIGN, TIME AND SETTING: A randomized, controlled animal study was performed at the Department of Anatomy, Weifang Medical University, China, from September 2007 to November 2008.MATERIALS: Dexamethasone (Shandong Huaxin Pharmaceutical, China) and rabbit anti-GAP-43 polyclonal antibody (Boster, China) were used.METHODS: All 36 healthy adult rabbits were randomly assigned to control group (n = 4), simple injury group (n = 20), and treatment group (n = 12). Intracanalicular optic nerve injury models were established using the metal cylinder free-fall impact method. The control group was left intact. The treatment group (four rabbits in each subgroup) was treated by optic nerve decompression, dexamethasone treatment (1 mg/kg daily via two intravenous infusions, 1/5 total dose reduction every 3 days, for 14 days), and simultaneously giving surgery and hormone treatment.MAIN OUTCOME MEASURES: Pathological changes in the retina were determined using hematoxylin-eosin staining. GAP-43 expression was detected using immunohistochemistry in the retina.RESULTS: Retina injury induced obvious pathological changes in the retina. With prolonged time after optic nerve injury, the number of retinal ganglion cells was gradually decreased, and reached the minimum on day 14 (P〈0.01). All three treatments increased the number of retinal ganglion cells (P〈0.01), but surgery + hormone treatment was most effective. No GAP-43 cells were present in the normal retinal, but they appeared 3 days after injury, peaked 7 days after injury, and then began to decline.CONCLUSION: Intracanalicular optic nerve injury induced obvious pathological changes in the retina, including increased GAP-43 expression. Optic canal decompression and hormones improved nerve repair after injury, and their combination produced better outcomes.展开更多
In this study, laboratory experiments are conducted to investigate the rapid decompression and desorption induced energetic failure in coal using a shock tube apparatus. Coal specimens are recovered from Colorado at a...In this study, laboratory experiments are conducted to investigate the rapid decompression and desorption induced energetic failure in coal using a shock tube apparatus. Coal specimens are recovered from Colorado at a depth of 610 m. The coal specimens are saturated with the strong sorbing gas CO2 for a certain period and then the rupture disc is suddenly broken on top of the shock tube to generate a shock wave propagating upwards and a rarefaction wave propagating downwards through the specimen.This rapid decompression and desorption has the potential to cause energetic fragmentation in coal.Three types of behaviors in coal after rapid decompression are found, i.e. degassing without fragmentation, horizontal fragmentation, and vertical fragmentation. We speculate that the characteristics of fracture network(e.g. aperture, spacing, orientation and stiffness) and gas desorption play a role in this dynamic event as coal can be considered as a dual porosity, dual permeability, dual stiffness sorbing medium. This study has important implications in understanding energetic failure process in underground coal mines such as coal gas outbursts.展开更多
Grains are widely present in industrial productions and processing,and are stored in silos.In the silo,auxiliary structures are added to achieve efficient production.However,little effort has been devoted to the influ...Grains are widely present in industrial productions and processing,and are stored in silos.In the silo,auxiliary structures are added to achieve efficient production.However,little effort has been devoted to the influence of the internal structure of the silo on the granular flow.In this work,a silo with a central decompression tube is studied through experimental measurements and discrete element methods.Then,the influences of the central decompression tube on the flow behavior of grains and wall pressure are analyzed.Results show that the grains are in mass flow in the silo without a central decompression tube,while the grains are in funnel flow in the silo with a central decompression tube.Moreover,regardless of whether there is a central decompression tube in the silo,the maximum pressure appears at the top of the conical silo.In the lower part of the silo,the wall pressure of the silo with a central decompression tube is lower than that of the silo without a central decompression tube.Therefore,a silo with a central decompression tube is more conducive to grain storage and discharge than a silo without a central decompression tube.展开更多
文摘Dear Editor,Ocular decompression retinopathy(ODR),which manifests as diffuse retinal hemorrhage occurring abruptly in multiple locations,including the subretinal,intraretinal,and preretinal spaces,is a rare complication after glaucoma surgery and is caused by sudden,iatrogenic lowering of intraocular pressure(IOP).Implicated procedures include glaucoma drainage implantation,trabeculectomy,iridotomy,and even cataract surgery[1].One report described a case of ocular decompression management following uncomplicated cataract surgery with no posterior capsular rupture or other intraoperative complications[2].Here,we report a rare case of ODR triggered by phacoemulsification and the use of systemic chemotherapeutic drugs in a patient with primary acute angleclosure glaucoma(PACG).The case not only improves our understanding of potential side effects of chemotherapeutic drugs on ophthalmic surgery but may also serve as a reference for clinicians in the management of patients with glaucoma with similar medical histories.
文摘Dear Editor,We present the first time,a case of a patient developed cerebrospinal fluid(CSF)leak and pneumocranium following optic canal decompression(OCD).INTRODUCTION Indirect traumatic optic neuropathy(ITON)impairs visual functions and quality of life.Endoscopic transnasal optic canal decompression(ETOCD)is one of the standard treatment strategies for the ITON.During the ETOCD,the optic nerve sheath are usually incised for sufficient decompression of optic nerve after removal of optic canal,which is associated with complications like CSF leakage,ophthalmic artery injury,and optic nerve injury[1].Generally,the mild CSF leak is common and can heal spontaneously using conventional treatment,the severe CSF leak requires surgical repair[2].
文摘Intra-abdominal hypertension(IAH)and abdominal compartment syndrome(ACS)play a pivotal role in the pathophysiology of severe acute pancreatitis(SAP)and contribute to new-onset and persistent organ failure.The optimal management of ACS involves a multi-disciplinary approach,from its early recognition to measures aiming at an urgent reduction of intra-abdominal pressure(IAP).A targeted literature search from January 1,2000,to November 30,2022,revealed 20 studies and data was analyzed on the type and country of the study,patient demographics,IAP,type and timing of surgical procedure performed,post-operative wound management,and outcomes of patients with ACS.There was no randomized controlled trial published on the topic.Decom-pressive laparotomy is effective in rapidly reducing IAP(standardized mean difference=2.68,95%confidence interval:1.19-1.47,P<0.001;4 studies).The morbidity and complications of an open abdomen after decompressive laparotomy should be weighed against the inadequately treated but,potentially lethal ACS.Disease-specific patient selection and the role of less-invasive decompressive measures,like subcutaneous linea alba fasciotomy or component separation techniques,is lacking in the 2013 consensus management guidelines by the Abdominal Compartment Society on IAH and ACS.This narrative review focuses on the current evidence regarding surgical decompression techniques for managing ACS in patients with SAP.However,there is a lack of high-quality evidence on patient selection,timing,and modality of surgical decompression.Large prospective trials are needed to identify triggers and effective and safe surgical decompression methods in SAP patients with ACS.
文摘BACKGROUND Whether hyperbaric oxygen therapy(HBOT)can cause paradoxical herniation is still unclear.CASE SUMMARY A 65-year-old patient who was comatose due to brain trauma underwent decompressive craniotomy and gradually regained consciousness after surgery.HBOT was administered 22 d after surgery due to speech impairment.Paradoxical herniation appeared on the second day after treatment,and the patient’s condition worsened after receiving mannitol treatment at the rehabilitation hospital.After timely skull repair,the paradoxical herniation was resolved,and the patient regained consciousness and had a good recovery as observed at the follow-up visit.CONCLUSION Paradoxical herniation is rare and may be caused by HBOT.However,the underlying mechanism is unknown,and the understanding of this phenomenon is insufficient.The use of mannitol may worsen this condition.Timely skull repair can treat paradoxical herniation and prevent serious complications.
文摘Severe acute cholangitis(AC)exacerbates the risk of death because of the rapid progression of the disease.The optimal timing of biliary decompression(BD)as a necessary intervention in patients with severe AC is controversial.A recently report titled“Timing of endoscopic retrograde cholangiopancreatography in the treatment of acute cholangitis of different severity”in the World Journal of Gastroenterology that the optimal time of endoscopic retrograde cholangiopancreatography for treating patients with severe AC is≤48 but not≤24 h,providing clinical evidence for selecting the optimal time for implementation of BD.Here,we discuss the controversy over the optimal timing of BD for AC based on guidelines and clinical evidence,and consider that more high-level clinical researches are urgent needed to benefit the management of patients with different severity of AC.
文摘Background: For decades, traditional open surgical techniques were used to treat lumbar disc herniation and lumbar canal stenosis (LCS). However, seeking for better outcomes for patients and avoiding extensive bony loss with its sequences had raised minimally invasive technique for treating these disorders as an alternative surgery. Methods: This is a retrospective study in which 54 patients of LCS were operated upon via unilateral minimally invasive technique to decompress the canal in a 360 degrees fashion through laminotomy, deroofing of opposite laminar side, sublaminar ligamintectomy, bilateral foraminotomies and discectomy. We used VAS scores and ODI to assess clinical outcomes with a period of one year follow-up. Results: Our results demonstrated that minimally invasive techniques for treating these disorders are effective procedures. Minimally invasive 360 degrees decompression for treating LCS had better outcomes regarding postoperative back pain, smaller incisions, less bony loss and early ambulation. Conclusion: Minimally invasive techniques for treating lumbar canal stenosis of different causes could be considered a better option instead of traditional full laminectomy with better outcomes as regards respecting the anatomical layers such as posterior spinal integrity and musculature, postoperative pain, accompanied with less blood loss, shorter hospital stays, and shorter recovery periods.
文摘AIM:To evaluate the predictive value of superficial retinal capillary plexus(SRCP)and radial peripapillary capillary(RPC)for visual field recovery after optic cross decompression and compare them with peripapillary nerve fiber layer(pRNFL)and ganglion cell complex(GCC).METHODS:This prospective longitudinal observational study included patients with chiasmal compression due to sellar region mass scheduled for decompressive surgery.Generalized estimating equations were used to compare retinal vessel density and retinal layer thickness preand post-operatively and with healthy controls.Logistic regression models were used to assess the relationship between preoperative GCC,pRNFL,SRCP,and RPC parameters and visual field recovery after surgery.RESULTS:The study included 43 eyes of 24 patients and 48 eyes of 24 healthy controls.Preoperative RPC and SRCP vessel density and pRNFL and GCC thickness were lower than healthy controls and higher than postoperative values.The best predictive GCC and pRNFL models were based on the superior GCC[area under the curve(AUC)=0.866]and the tempo-inferior pRNFL(AUC=0.824),and the best predictive SRCP and RPC models were based on the nasal SRCP(AUC=0.718)and tempo-inferior RPC(AUC=0.825).There was no statistical difference in the predictive value of the superior GCC,tempo-inferior pRNFL,and tempo-inferior RPC(all P>0.05).CONCLUSION:Compression of the optic chiasm by tumors in the saddle area can reduce retinal thickness and blood perfusion.This reduction persists despite the recovery of the visual field after decompression surgery.GCC,pRNFL,and RPC can be used as sensitive predictors of visual field recovery after decompression surgery.
文摘We suggest that during severe acute pancreatitis(SAP)with intra-abdominal hypertension,practitioners should consider decompressive laparotomy,even with intra-abdominal pressure(IAP)below 25 mmHg.Indeed,in this setting,non-occlusive mesenteric ischemia(NOMI)may occur even with IAP below this cutoff and lead to transmural necrosis if abdominal perfusion pressure is not promptly restored.We report our experience of 18 critically ill patients with SAP having undergone decompressive laparotomy of which one third had NOMI while IAP was mostly below 25 mmHg.
基金supported by Shandong Province Natural Science Foundation of China:sd2018762872
文摘Objective:To observe the effect of recombinant human bone morphogenetic protein 2/polylactide-co-glycolic acid(rhBMP-2/PLGA) with core decompression on repair of rabbit femoral head necrosis.Methods:Bilateral femoral head necrosis models of rabbit were established by steroid injection.A total of 48 rabbits(96 femoral head necrosis) were randomly divided into 4groups:Group A,control group with12 rabbits,24 femoral head necrosis;Group B,treated with rhBMP-2/PLCA implantation after core depression,with 12 rabbits,24 femoral head necrosis;Group C,treated with rhBMP-2 implantation after core depression,with 12 rabbits,24 femoral head necrosis;Croup D treated with core depression group without implantation,with 12 rabbits,24 femoral head necrosis.All animals were sacrificed after 12 weeks.The ability of repairing bone defect was evaluated by X-ray radiograph.Bone mineral density analysis of the defect regions were used to evaluate the level of ossification.The morphologic change and bone formation was assessed by HE staining.The angiogenesis was evaluated by VEGF immunohistochemistry.Results:The osteogenetic ability and quality of femoral head necrosis in group B were better than those of other groups after 12 weeks by X-ray radiograph and morphologic investigation.And the angiogenesis in group B was better than other groups.Group C had similar osteogenetic quality of femoral head necrosis and angiogenesis with group D.Conclusions:The treatment of rhBMP-2/PLCA implantation after core depression can promote the repair of rabbit femoral head necrosis.It is a promising and efficient synthetic bone material to treat the femoral head necrosis.
基金Supported by the National Natural Science Foundation of China (No.81670885)the Science and Technology Program of Guangdong Province, China (No.2013B020400003)the Science and Technology Program of Guangzhou, China (No.15570001)
文摘AIM: To report the effects of intravenous high-dose glucocorticoids(iv GC) and orbital decompression(OD) surgery for treatment of sight-threatening thyroid-associated ophthalmopathy(TAO).METHODS: A retrospective review of medical records from patients with sight-threatening TAO [definite or highly suspected dysthyroid optic neuropathy(DON)] treated with iv GC(60 cases) and OD(25 cases) was conducted at the Zhongshan Ophthalmic Center between January 2001 and January 2009. Patients were initially treated with iv GC(iv GC group). If no significant improvement in visual function was obtained, they then received OD surgery(OD group). The pre-versus post-treatment efficacies of either iv GC or OD in these patients were assessed using several indices, including visual acuity, intraocular pressure, ocular alignment, ocular motility, and exophthalmos. RESULTS: Nighty-one eyes had definite DON while 79 were considered to have highly suspected DON. In the iv GC group, 51 individuals(85.0%) eventually demonstrated normal vision, while 10 patients(16.7%) demonstrated a reduction in deviation(P<0.01), and 35 cases(58.3%) showed slight improvements in ocular motility(P<0.01). In OD group, visual acuity improved in 24 cases(96.0%, P<0.01) and all patients showed varying reductions of exophthalmos(mean: 4.35±1.13 mm, P<0.01). Eight cases(32.0%) experienced an 8-15 PD reduction of deviation and ocular motility improved in 12 cases(48.0%), while 3 patients(12.0%) developed new-onset strabismus with diplopia post-surgically(P<0.01). Patients were followed up at an average of 1.55±1.07 y. CONCLUSION: Both iv GC and OD show good therapeutic efficacy in the treatment of sight-threatening TAO. Thepresence of extremely poor eyesight(≥0.5 log MAR) was corrected in some patients with iv GC alone, thus sparing these patients from subsequent OD surgery. In patients who were refractory to steroids, subsequent OD surgery often provided satisfactory outcomes, however, new-onset strabismus with diplopia was observed in 12.0% of these cases.
文摘BACKGROUND:Excessive hepatocyte apoptosis and bile lakes in severe obstructive jaundice might impair liver functions.Although decompression of the bile duct has been reported to improve liver functions in animal studies,the mechanism of obstruction differs from that in humans.This study aimed to determine the profiles of hepatocyte apoptosis and bile lakes following bile duct decompression in patients with severe obstructive jaundice in the clinical setting.METHODS:We conducted a 'before and after study' on severe obstructive jaundice patients as a model of inhibition of the excessive process by bile duct decompression.Specimens of liver biopsies were taken before and after decompression of the bile duct and then stained by terminal deoxynucleotide transferase-mediated dUTP nick end-labeling(TUNEL) to identify hepatocyte apoptosis and by hematoxilin-eosin(HE) to identify bile lakes.All measurements were independently done by 2 observers.RESULTS:Twenty-one severe obstructive jaundice patients were included.In all patients,excessive hepatocyte apoptosis and bile lakes were apparent.After decompression,the hepatocyte apoptosis index decreased from 53.1(SD 105) to 11.7(SD 13.6)(P<0.05),and the bile lakes from 23.6(SD 14.8) to 10.9(SD 6.9)(P<0.05).CONCLUSION:Bile duct decompression improves hepatocyte apoptosis and bile lakes in cases of severe obstructive jaundice,similar to the findings in animal studies.
文摘U-shaped sacral fractures are rare and often difficult to diagnose primarily due to the difficulty in obtaining adequate imaging and the severe associated injuries. These fractures are highly unstable and frequently cause neurological deficits. The majority of surgeons have limited experience in management of U-shaped sacral fractures. No standard treatment protocol for U-shaped sacral fractures has been available till now. This study aimed to examine the management of U-shaped sacral fractures and the early outcomes. Clinical data of 15 consecutive patients with U-shaped sacral fracture who were admitted to our trauma center between 2009 and 2014 were retrospectively analyzed. Demographics, fracture classification, mechanism of injury and operative treatment and deformity angle were assessed. All the patients were treated with lumbopelvic fixation or (and) sacral decompression. EQ-5d score was applied to evaluate the patients' quality of life. Of the 15 consecutive patients with U-shaped sacral fracture, the mean age was 28.8 years (range: 15-55 years) at the time of injury. There were 6 females and 9 males. The mean follow- up time was 22.7 months (range: 9-47 months) and mean full weight-bearing time was 9.9 weeks (range: 8-14 weeks). Ten patients received lumbopelvic fixation and sacral decompression, one lombosacral fixation, and 4 merely sacral decompression due to delayed diagnosis or surgery. The post-operation deformity angle (mean 27.87°, and range: 8°-90°) of the sacrum was smaller than that pre-operation (mean 35.67; range: 15-90) with no significance difference noted. At the latest follow-up, all patients obtained neurological recovery with different extents. Visual analogue score (VAS) was reduced from preoperative 7.07 (range: 5-9) to postoperetive 1.93 (range: 1-3). All patients could walk without any aid after treatment. Eight patients were able to care for themselves and undertook some daily activities. Five patients had returned to work full time. In conclusion, lumbopelvic fixation is an effective method for stabilization of U-shaped sacral fractures with fewer complications developed. Effective reduction and firm fixation are the prerequisite of early mobilization and neurological recovery. Sacral decompression effectively promotes neurological recovery even in patients with old U-shaped sacral fractures.
文摘AIM: To evaluate the long-term results of different orbital decompression techniques performed in patients with Graves' ophthalmopathy(GO).METHODS: Totally 170 cases with GO underwent orbital decompression between 1994 and 2014. Patients were divided into 4 groups as medial-inferior, mediallateral(balanced), medial-lateral-inferior, and lateral only according to the applied surgical technique. Surgical indications, regression degrees on Hertel exophthalmometer, new-onset diplopia in the primary gaze and new-onset gaze-evoked diplopia after surgery and visual acuity in cases with dysthyroid optic neuropathy(DON) were compared between different surgical techniques.RESULTS: The study included 248 eyes of 149 patients. The mean age for surgery was 42.3±13.2 y. DON was the surgical indication in 36.6% of cases, and three-wall decompression was the most preferred technique in these cases. All types of surgery significantly decrease the Hertel values(P〈0.005). Balanced medial-lateral, and only lateral wall decompression caused the lowest rate of postoperative new-onset diplopia in primary gaze. The improvement of visual acuity in patients with DON did not significantly differ between the groups(P=0.181). CONCLUSION: The study show that orbital decompression surgery has safe and effective long term results for functional and cosmetic rehabilitation of GO. It significantly reduces Hertel measurements in disfiguring proptosis and improves visual functions especially in DON cases.
基金Supported by the Natural Science Foundation of China(No.81371028)Natural Science Foundation of Zhejiang Province,China(No.LY12H12006)the Guided Innovation Project of the Eye Hospital of Wenzhou Medical University(No.YNCX201104)
文摘AIM: To investigate a possible correlation between visual acuity(VA) prognosis and the presence at baseline of various orbital and ocular signs in patients affected by indirect traumatic optic neuropathy(ITON). METHODS: From July 1 st, 2012 to July 1 st, 2015, 224 adults diagnosed with ITON who underwent endoscopic transethmosphenoid optic canal decompression(ETOCD) were reviewed. Visual outcome before and after treatment were taken into comparison. RESULTS: Accompanied older in age, longer time to medical treatment and existence of optic canal fracture(OCF) were the independent predictors for poor postoperative VA and lower improvement degree of visual acuity(IDVA), while worse preoperative VA was predictive factor for poor postoperative VA only. Mean value of IDVA in patients with OCF was 0.19±0.30. Mean value of IDVA in patients without OCF was 0.29±0.35. IDVA in cases without OCF was significant higher than those with OCF(t=2.272, P〈0.05). CONCLUSION: Patients suffered from ITON without OCF before ETOCD have better surgical outcome than those with OCF. Older in age, longer time to medical treatment and existence of OCF are independent factors for poor VA prognosis and lower IDVA. Preoperative VA is independent factor for VA prognosis only.
文摘Primary hemifacial spasm(HFS) is a disorder that causes frequent involuntary contractions in the muscles on one side of the face, due to a blood vessel compressing the nerve at its root exit zone(REZ) from the brainstem. Numerous prospective and retrospective case series have confirmed the efficacy of microvascular decompression(MVD) of the facial nerve in patients with HFS. However, while MVD is effective, there are still significant postoperative complications. In this paper, recent technological advances related to MVD(such as lateral spread response,brainstem auditory evokes potential, three dimensional time of flight magnetic resonance angiography, intraoperative neuroendoscopy) are reviewed for the purposes of improving MVD treatment efficacy and reducing postoperative complications.
基金This project was supported by the Natural Science Foundation of Anhui Province,China(1408085MH154).
文摘Purpose:To investigate the safety and feasibility of radical total gastrectomy without postoperative gastrointestinal decompression in elderly patients with gastric cancer.Methods:Elderly patients(65e80 years of age)hospitalized with gastric cancer from May 2009 to August 2012 were selected to receive radical total gastrectomy with(controls,n=39)or without(n=37)postoperative gastrointestinal decompression.Postoperative recovery conditions and associated complications were observed and compared.Results:In the group without decompression,the first passage of flatus post-operation was significantly earlier,and scores of nausea,pharyngitis,insomnia,and postoperative ambulation limitation were significantly reduced compared to controls(all p<0.01).However,there were no differences in the degree of abdominal distension,time to first anal defecation,or incidence of postoperative complications between the groups.Conclusion:Gastrointestinal decompression is not necessary after total gastrectomy in elderly gastric cancer patients,and may improve patient comfort and recovery.
基金supported by a grant from the Anhui Provincial Health Department-Funded Medical Research Project in 2009 in China,No.09C33a grant from the Key Scientific Research Project of Cultivating Fund of Wannan Medical College in China,No.WK2014ZF14
文摘A variety of inlfammatory cytokines are involved in spinal cord injury and inlfuence the recov-ery of neuronal function. In the present study, we established a rat model of acute spinal cord injury by cerclage. The cerclage suture was released 8 or 72 hours later, to simulate decompres-sion surgery. Neurological function was evaluated behaviorally for 3 weeks after surgery, and tumor necrosis factorα immunoreactivity and apoptosis were quantiifed in the region of injury. Rats that underwent decompression surgery had significantly weaker immunoreactivity of tumor necrosis factorα and signiifcantly fewer apoptotic cells, and showed faster improvement of locomotor function than animals in which decompression surgery was not performed. De-compression at 8 hours resulted in signiifcantly faster recovery than that at 72 hours. These data indicate that early decompression may improve neurological function after spinal cord injury by inhibiting the expression of tumor necrosis factorα.
基金the Educational Commission of Shandong Province of China,No. J06L23
文摘BACKGROUND: The main clinical treatments for optic nerve injury are optic canal decompression and systemic administration of hormones, but both treatments have disadvantages. OBJECTIVE: To observe the pathological changes in the retina and growth associated protein-43 (GAP-43) expression, to compare the treatment of optic canal decompression, hormones, and their combination with the intracanalicular optic nerve injury.DESIGN, TIME AND SETTING: A randomized, controlled animal study was performed at the Department of Anatomy, Weifang Medical University, China, from September 2007 to November 2008.MATERIALS: Dexamethasone (Shandong Huaxin Pharmaceutical, China) and rabbit anti-GAP-43 polyclonal antibody (Boster, China) were used.METHODS: All 36 healthy adult rabbits were randomly assigned to control group (n = 4), simple injury group (n = 20), and treatment group (n = 12). Intracanalicular optic nerve injury models were established using the metal cylinder free-fall impact method. The control group was left intact. The treatment group (four rabbits in each subgroup) was treated by optic nerve decompression, dexamethasone treatment (1 mg/kg daily via two intravenous infusions, 1/5 total dose reduction every 3 days, for 14 days), and simultaneously giving surgery and hormone treatment.MAIN OUTCOME MEASURES: Pathological changes in the retina were determined using hematoxylin-eosin staining. GAP-43 expression was detected using immunohistochemistry in the retina.RESULTS: Retina injury induced obvious pathological changes in the retina. With prolonged time after optic nerve injury, the number of retinal ganglion cells was gradually decreased, and reached the minimum on day 14 (P〈0.01). All three treatments increased the number of retinal ganglion cells (P〈0.01), but surgery + hormone treatment was most effective. No GAP-43 cells were present in the normal retinal, but they appeared 3 days after injury, peaked 7 days after injury, and then began to decline.CONCLUSION: Intracanalicular optic nerve injury induced obvious pathological changes in the retina, including increased GAP-43 expression. Optic canal decompression and hormones improved nerve repair after injury, and their combination produced better outcomes.
基金a partial result of funding by NIOSH under contract200-2008-25702the National Science Foundation under grant EAR-0842134
文摘In this study, laboratory experiments are conducted to investigate the rapid decompression and desorption induced energetic failure in coal using a shock tube apparatus. Coal specimens are recovered from Colorado at a depth of 610 m. The coal specimens are saturated with the strong sorbing gas CO2 for a certain period and then the rupture disc is suddenly broken on top of the shock tube to generate a shock wave propagating upwards and a rarefaction wave propagating downwards through the specimen.This rapid decompression and desorption has the potential to cause energetic fragmentation in coal.Three types of behaviors in coal after rapid decompression are found, i.e. degassing without fragmentation, horizontal fragmentation, and vertical fragmentation. We speculate that the characteristics of fracture network(e.g. aperture, spacing, orientation and stiffness) and gas desorption play a role in this dynamic event as coal can be considered as a dual porosity, dual permeability, dual stiffness sorbing medium. This study has important implications in understanding energetic failure process in underground coal mines such as coal gas outbursts.
基金We would like to acknowledge the finical support by the Key Laboratory of Agro-Products Postharvest Handling,Ministry of Agriculture support(Grant No.KLAPPH2-2017-04).
文摘Grains are widely present in industrial productions and processing,and are stored in silos.In the silo,auxiliary structures are added to achieve efficient production.However,little effort has been devoted to the influence of the internal structure of the silo on the granular flow.In this work,a silo with a central decompression tube is studied through experimental measurements and discrete element methods.Then,the influences of the central decompression tube on the flow behavior of grains and wall pressure are analyzed.Results show that the grains are in mass flow in the silo without a central decompression tube,while the grains are in funnel flow in the silo with a central decompression tube.Moreover,regardless of whether there is a central decompression tube in the silo,the maximum pressure appears at the top of the conical silo.In the lower part of the silo,the wall pressure of the silo with a central decompression tube is lower than that of the silo without a central decompression tube.Therefore,a silo with a central decompression tube is more conducive to grain storage and discharge than a silo without a central decompression tube.