Academic literature on the topic 'LP shunt'

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Journal articles on the topic "LP shunt"

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Marupudi, Neena I., Carolyn Harris, Tanya Pavri, et al. "The role of lumboperitoneal shunts in managing chronic hydrocephalus with slit ventricles." Journal of Neurosurgery: Pediatrics 22, no. 6 (2018): 632–37. http://dx.doi.org/10.3171/2018.6.peds17642.

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OBJECTIVELumboperitoneal (LP) shunts have a role not only in pseudotumor cerebri, but also in patients with slit-like ventricles who are treated with CSF shunting on a chronic basis. Hesitation to utilize LP shunts is based on previous conventional beliefs including the tendency for overdrainage, difficulties accessing the shunt to tap or revise, and risk of progressive cerebellar tonsillar herniation. The authors hypothesized that the use of horizontal-vertical (HV) valves may reduce the risk of these complications, particularly overdrainage and development of Chiari malformation.METHODSAll pediatric cases involving patients treated with an LP shunt at the Children’s Hospital of Michigan were reviewed in this retrospective case series. A total of 143 patients with hydrocephalus were treated with LP shunts from 1997–2015 (follow-up range 8 months–8 years, median 4.2 years). Patients with pseudotumor cerebri underwent placement of an LP shunt as a primary procedure. In patients with slit ventricles from chronically treated hydrocephalus or repeated shunt malfunctions from proximal catheter obstruction, a lumbar drain was inserted to assess candidacy for conversion to an LP shunt. In patients who tolerated the lumbar drain and demonstrated communication of the ventricles with the spinal cisterns, treatment was converted to an LP shunt. All patients included in the series had undergone initial shunt placement between birth and age 16 years.RESULTSIn 30% of patients (n = 43), LP shunts were placed as the initial shunt treatment; in 70% (n = 100), treatment was converted to LP shunts from ventriculoperitoneal (VP) shunts. The patients’ age at insertion of or conversion to an LP shunt ranged from 1 to 43 years (median 8.5 years). Of the patients with clear pre-LP and post-LP shunt follow-up imaging, none were found to develop an acquired Chiari malformation. In patients with pre-existing tonsillar ectopia, no progression was noted on follow-up MRIs of the brain in these patients after LP shunt insertion. In our LP shunt case series, no patient presented with acute deterioration from shunt malfunction.CONCLUSIONSConversion to an LP shunt may minimize acute deterioration from shunt malfunction and decrease morbidity of repeated procedures in patients with chronically shunt-treated hydrocephalus and small ventricles. In comparison to previously published case series of LP shunt treatment, the use of LP shunts in conjunction with HV valves may decrease the overall risk of cerebellar tonsillar herniation. The use of an LP shunt may be an alternative in the management of slit ventricles when VP shunting repeatedly fails.
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Yang, Tsung-Hsi, Cheng-Siu Chang, Wen-Wei Sung, and Jung-Tung Liu. "Lumboperitoneal Shunt: A New Modified Surgical Technique and a Comparison of the Complications with Ventriculoperitoneal Shunt in a Single Center." Medicina 55, no. 10 (2019): 643. http://dx.doi.org/10.3390/medicina55100643.

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Background and objectives: Hydrocephalus remains a disease requiring surgical treatment even in the modern era. Ventriculoperitoneal (VP) shunt placement is the most common treatment, whereas lumboperitoneal (LP) shunts are less commonly used due to initial reports of very high rates of complications. In the present study, we retrospectively reviewed our experience of the new two-stage procedure with LP shunt implantation to assess the complications and the results of this procedure versus VP shunt insertion. Materials and Methods: All patients from a single center who had received LP shunts using a Medtronic Strata device or VP shunts in the past six-year interval were retrospectively reviewed. The LP shunt insertion was a new two-stage procedure. We compared the three major complications and shunt revisions between the two groups, including shunt malfunction, infection, and subdural hematoma. Results: After matching the age and sex of both groups, we included 96 surgery numbers of LP shunts and 192 surgery numbers of VP shunts for comparison. In the LP shunt group, one patient (1.0%) underwent revision of the shunt due to shunt infection. In the VP shunt group, 26 surgeries (13.5%) needed revision, and 11 surgeries (5.7%) had shunt infection. Shunt malfunction occurred in 14 patients (7.3%) and all needed revisions. The revision rate showed statistically significant differences between the LP and VP shunt groups (p < 0.001). Conclusions: The recent improvements in the quality of the LP shunt device and the proficiency of the procedure has made the LP shunt a safer procedure than the VP shunt. The programmable valve can avoid overdrainage complications and reduce the revision rate. With our procedural steps, the LP shunt can be used to decrease the complications and revision rates.
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Chen, Yu-Hsi, Yu-Hsuan Chung, Chun-Yi Li, and Ming-Hsien Hu. "Lumboperitoneal Shunt Transection during Minimally Invasive Lumbar Spine Posterior Instrumentation: A Case Report and Literature Review." Formosan Journal of Musculoskeletal Disorders 16, no. 2 (2025): 80–83. https://doi.org/10.4103/fjmd.fjmd-d-24-00014.

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Abstract Minimally invasive surgery (MIS) has rapidly gained popularity over the past decade; however, MIS pedicle screw placement can pose risks to existing devices, such as lumboperitoneal (LP) shunts, if the surgeon is unaware of their presence. Damage to the LP shunt can lead to serious complications, highlighting the importance of spine, abdominal, and pelvic surgeons being mindful of shunt-related issues. A 70-year-old female with an LP shunt for normal-pressure hydrocephalus fell and sustained an L3 burst fracture with radiculopathy. During percutaneous pedicle screw placement, patient’s LP shunt was transected. A neurosurgeon was consulted but was unavailable to perform the LP shunt revision at that time. Owing to limited materials and surgical experience, the LP shunt was not revised or reconnected during the initial surgery. Two months later, the patient presented with a mild headache and unsteady gait. A computed tomography scan revealed enlarged ventricles. The patient subsequently underwent successful revision of the LP shunt placement and achieved full recovery. This case report emphasizes the prevention of complications arising from MIS screw placement that interfered with a previously placed LP shunt, particularly near the entry point and along the path of the pedicle screw. MIS pedicle screw placement has become a popular surgical procedure. However, without direct visualization through open exposure, careful preoperative planning, from determining the entry point to routing the screw, should be performed cautiously to prevent injury to neighboring structures and existing devices, such as LP shunts. Otherwise, additional surgery may be necessary to repair the LP shunt and restore its function.
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Menger, Richard P., David E. Connor, Jai Deep Thakur, et al. "A comparison of lumboperitoneal and ventriculoperitoneal shunting for idiopathic intracranial hypertension: an analysis of economic impact and complications using the Nationwide Inpatient Sample." Neurosurgical Focus 37, no. 5 (2014): E4. http://dx.doi.org/10.3171/2014.8.focus14436.

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Object Complications following lumboperitoneal (LP) shunting have been reported in 18% to 85% of cases. The need for multiple revision surgeries, development of iatrogenic Chiari malformation, and frequent wound complications have prompted many to abandon this procedure altogether for the treatment of idiopathic benign intracranial hypertension (pseudotumor cerebri), in favor of ventriculoperitoneal (VP) shunting. A direct comparison of the complication rates and health care charges between first-choice LP versus VP shunting is presented. Methods The Nationwide Inpatient Sample database was queried for all patients with the diagnosis of benign intracranial hypertension (International Classification of Diseases, Ninth Revision, code 348.2) from 2005 to 2009. These data were stratified by operative intervention, with demographic and hospitalization charge data generated for each. Results A weighted sample of 4480 patients was identified as having the diagnosis of idiopathic intracranial hypertension (IIH), with 2505 undergoing first-time VP shunt placement and 1754 undergoing initial LP shunt placement. Revision surgery occurred in 3.9% of admissions (n = 98) for VP shunts and in 7.0% of admissions (n = 123) for LP shunts (p < 0.0001). Ventriculoperitoneal shunts were placed at teaching institutions in 83.8% of cases, compared with only 77.3% of first-time LP shunts (p < 0.0001). Mean hospital length of stay (LOS) significantly differed between primary VP (3 days) and primary LP shunt procedures (4 days, p < 0.0001). The summed charges for the revisions of 92 VP shunts ($3,453,956) and those of the 6 VP shunt removals ($272,484) totaled $3,726,352 over 5 years for the study population. The summed charges for revision of 70 LP shunts ($2,229,430) and those of the 53 LP shunt removals ($3,125,569) totaled $5,408,679 over 5 years for the study population. Conclusions The presented results appear to call into question the selection of LP shunt placement as primary treatment for IIH, as this procedure is associated with a significantly greater likelihood of need for shunt revision, increased LOS, and greater overall charges to the health care system.
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Aoki, Nobuhiko. "Lumboperitoneal Shunt: Clinical Applications, Complications, and Comparison with Ventriculoperitoneal Shunt." Neurosurgery 26, no. 6 (1990): 998–1004. http://dx.doi.org/10.1227/00006123-199006000-00013.

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Abstract Lumboperitoneal (LP) shunting has the advantage of completely extracranial surgical management, minimizing intracranial complications. An LP shunt has been intentionally adopted for patients who require cerebrospinal fluid diversion. A retrospective study was designed to examine the indications for and complications associated with LP shunts in 207 patients (including 28 pediatric patients) treated during the past 11 years. Follow-up averaging 5.1 years revealed no deaths related directly to LP shunt placement. Twenty-nine patients (14%) underwent revision of the shunt because of obstruction. Shunt-related infections were observed in only 2 patients (1%). Radicular pain occurred in 10 patients (5%), 2 of whom required shunt replacement. Postoperative occurrence of dyspnea and disturbance of consciousness necessitated conversion to a ventriculoperitoneal (VP) shunt in 2 patients (1%), who subsequently were noted to have Chiari malformations. In 4 patients (2%), an acute subdural hematoma developed after mild head trauma, Symptomatic chronic subdural hematomas were observed in 2 patients (1%). One patient had a mild myelopathy that rapidly resolved after shunt replacement. The comparison to 120 patients treated with a VP shunt during the identical period (an average follow-up of 5.2 years) suggests the following conclusions. After subarachnoid hemorrhage caused by a ruptured aneurysm, hydrocephalus is usually of the communicating type and is an indication for an LP shunt. The incidence of infection and malfunction with an LP shunt is significantly lower than that with a VP shunt. An LP shunt is also indicated for pediatric patients, although a relatively higher incidence of malfunction is noted compared to adults. In the light of their simplicity, extracranial management, and fewer complications, it is suggested that LP shunts be more widely used by neurosurgeons.
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Wang, Vincent Y., Nicholas M. Barbaro, Michael T. Lawton, et al. "COMPLICATIONS OF LUMBOPERITONEAL SHUNTS." Neurosurgery 60, no. 6 (2007): 1045–49. http://dx.doi.org/10.1227/01.neu.0000255469.68129.81.

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Abstract OBJECTIVE Placement of a lumboperitoneal (LP) shunt is a method for treating communicating hydrocephalus. These shunts can be placed with or without valves. We sought to review the complications associated with the use of LP shunts with the increasing use of horizontal-vertical (HV) valve systems. PATIENTS AND METHODS A retrospective chart review of all patients who received LP shunts at University of California, San Francisco from 1998 to 2005 was performed. RESULTS Of the 74 patients identified in this study, 67 underwent LP shunt placement for the first time, and seven patients had revisions of LP shunts that were originally placed at another hospital. There were a total of 44 revisions for the entire group: 27 patients had one revision, 10 patients had two or three revisions, and one patient had five revisions. Obstruction or migration of the peritoneal catheter was the most common reason for revision. The HV valve was responsible for shunt malfunction in nine patients and was the second-most common site of system problems. Overdrainage symptoms were observed in 11 patients, most of whom had LP shunts without any valve. No patients with an HV valve system developed an acquired Chiari malformation. There were three cases of infection, two of which required removal of the LP shunt. CONCLUSION Overall, the placement of LP shunts for the treatment of communicating hydrocephalus seems to be a safe procedure. Serious complications such as subdural hematoma were not observed. The HV valve was associated with minor complications, but it was effective in reducing the incidence of overdrainage.
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Mcgirt, Matthew J., Graeme Woodworth, George Thomas, Neil Miller, Michael Williams, and Daniele Rigamonti. "Cerebrospinal fluid shunt placement for pseudotumor cerebri—associated intractable headache: predictors of treatment response and an analysis of long-term outcomes." Journal of Neurosurgery 101, no. 4 (2004): 627–32. http://dx.doi.org/10.3171/jns.2004.101.4.0627.

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Object. Cerebrospinal fluid (CSF) shunts effectively reverse symptoms of pseudotumor cerebri postoperatively, but long-term outcome has not been investigated. Lumboperitoneal (LP) shunts are the mainstay of CSF shunts for pseudotumor cerebri; however, image-guided stereotaxy and neuroendoscopy now allow effective placement of a ventricular catheter without causing ventriculomegaly in these cases. To date it remains unknown if CSF shunts provide long-term relief from pseudotumor cerebri and whether a ventricular shunt is better than an LP shunt. The authors investigated these possibilities. Methods. The authors reviewed the records of all shunt placement procedures that were performed for intractable headache due to pseudotumor cerebri at one institution between 1973 and 2003. Using proportional hazards regression analysis, predictors of treatment failure (continued headache despite a properly functioning shunt) were assessed, and shunt revision and complication rates were compared between LP and ventricular (ventriculoperitoneal [VP] or ventriculoatrial [VAT]) shunts. Forty-two patients underwent 115 shunt placement procedures: 79 in which an LP shunt was used and 36 in which a VP or VAT shunt was used. Forty patients (95%) experienced a significant improvement in their headaches immediately after the shunt was inserted. Severe headache recurred despite a properly functioning shunt in eight (19%) and 20 (48%) patients by 12 and 36 months, respectively, after the initial shunt placement surgery. Seventeen patients without papilledema and 19 patients in whom preoperative symptoms had occurred for longer than 2 years experienced recurrent headache, making patients with papilledema or long-term symptoms fivefold (relative risk [RR] 5.2, 95% confidence interval [CI] 1.5–17.8; p < 0.01) or 2.5-fold (RR 2.51, 95% CI 1.01–9.39; p = 0.05) more likely to experience headache recurrence, respectively. In contrast to VP or VAT shunts, LP shunts were associated with a 2.5-fold increased risk of shunt revision (RR 2.5, 95% CI 1.5–4.3; p < 0.001) due to a threefold increased risk of shunt obstruction (RR 3, 95% CI 1.5–5.7; p < 0.005), but there were similar risks between the two types of shunts for overdrainage (RR 2.3, 95% CI 0.8–7.9; p = 0.22), distal catheter migration (RR 2.1, 95% CI 0.3–19.3; p = 0.55), and shunt infection (RR 1.3, 95% CI 0.3–13.2; p = 0.75). Conclusions. Based on their 30-year experience in the treatment of these patients, the authors found that CSF shunts were extremely effective in the acute treatment of pseudotumor cerebri—associated intractable headache, providing long-term relief in the majority of patients. Lack of papilledema and long-standing symptoms were risk factors for treatment failure. The use of ventricular shunts for pseudotumor cerebri was associated with a lower risk of shunt obstruction and revision than the use of LP shunts. Using ventricular shunts in patients with papilledema or symptoms lasting less than 2 years should be considered for those with pseudotumor cerebri—associated intractable headache.
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Mohammad, Mohammad, Hisham Al-Khayat, Kenneth Katchy, and Shervin Pejhan. "Neurenteric cyst secondary to lumboperitoneal shunt." Surgical Neurology International 11 (January 24, 2020): 14. http://dx.doi.org/10.25259/sni_589_2019.

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Background: Neurenteric cysts are rare lesions that typically present in the upper thoracic and cervical spine and are occasionally found intracranially. The optimal treatment is gross total excision as subtotal/partial excisions are associated with high recurrence rates. Case Description: For the past 10 years, a patient with pseudotumor cerebri required repeated lumboperitoneal (LP) shunt revisions. This resulted in multiple neuroenterogenous cysts occurring around the proximal LP subarachnoid shunt catheter, a finding likely attributable to retrograde flow from the peritoneal cavity. Conclusion: Unlike ventriculoperitoneal (VP) shunts and LP shunts do not contain valves, making the retrograde passage of enterogenous cells possible when abdominal pressure exceeds lumbar subarachnoid pressure, especially in the morbidly obese patient.
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Ayvalık, Fatih, Rafet Ozay, Erhan Turkoglu, Mehmet Balkan, and Zeki Şekerci. "Remote Cerebellar Hemorrhage Following Lumboperitoneal Shunt Insertion: A Rare Case Report." Surgery Journal 02, no. 04 (2016): e139-e142. http://dx.doi.org/10.1055/s-0036-1594245.

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Idiopathic intracranial hypertension is characterized by high intracranial pressure without hydrocephalus or intracranial mass. Surgical treatment includes optic nerve fenestration and insertion of ventriculoperitoneal and lumboperitoneal (LP) shunts. For decreasing intracranial pressure, cerebrospinal fluid (CSF) LP shunt is widely used for the surgical management; it also carries complications such as shunt migration, venous sinus thrombosis, subarachnoid hemorrhage, and subdural and intracerebral hematoma. A 52-year-old man was admitted to the neurosurgery clinic with severe headache, retro-orbital pain, and blurred vision. Lumbar puncture demonstrated that the CSF opening pressure was 32 cm H2O. A nonprogrammable LP shunt with two distal slit valves was inserted. Shortly after the surgery, his condition deteriorated and he became comatose. Immediate computed tomography scan revealed cerebellar hemorrhage and acute hydrocephalus. Development of remote cerebellar hemorrhage following LP shunt is rare. We discuss this rare event and the applicable literature.
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Nadkarni, Trimurti D., Harold L. Rekate, and Donna Wallace. "Concurrent use of a lumboperitoneal shunt with programmable valve and ventricular access device in the treatment of pseudotumor cerebri: review of 40 cases." Journal of Neurosurgery: Pediatrics 2, no. 1 (2008): 19–24. http://dx.doi.org/10.3171/ped/2008/2/7/019.

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Object The authors evaluated the efficacy of treating patients with pseudotumor cerebri (PTC) and headaches due to increased intracranial pressure (ICP) by using a lumboperitoneal (LP) shunt with a programmable valve and ventricular access device (VAD). Methods Forty patients in whom PTC was diagnosed were treated using LP shunts with programmable valves and wand-guided placement of a VAD. All patients had papilledema and high opening pressure during spinal tap. The mean follow-up was 18 months (range 3–72 months). When patients complained of headaches that suggested shunt malfunction, the ventricular reservoir was tapped at bedside to assess ICP. The programmable valve was adjusted based on the patient's headache and ICP. Results The VAD was tapped in 21 patients, and the LP valve was redialed in 14. Shunt malfunction was diagnosed accurately. The 10 patients undergoing revision were all found to have shunt obstruction except 1 whose valve was replaced because it could not be reprogrammed. No patient treated with a shunt developed a Chiari malformation. The VAD was exposed in 4 patients with infection or wound breakdown. The LP shunt was revised in 2 patients who developed a pseudomeningocele. In 1 patient, a small bowel obstruction responded to conservative management. Seven patients had headaches despite documented normal ICP. That is, the headaches were unrelated to shunt function, and these patients were referred to a pain management clinic. Conclusions Lumboperitoneal shunts with programmable valves effectively controlled the outflow of lumbar cerebrospinal fluid to ameliorate the symptoms of PTC. The VAD permitted assessment of ICP and thus, indirectly, LP shunt function, and benefits outweighed risks. The programmable valve permitted cerebrospinal fluid flow to be adjusted based on patients' clinical status and ICP to be measured by the VAD.
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Book chapters on the topic "LP shunt"

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Ishiwata, Yusuke. "Analysis of CSF Flow Through LP Shunt During Change of Posture." In Annual Review of Hydrocephalus. Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-662-11158-1_41.

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"Lumboperitoneal Shunt (LP Shunt)." In Encyclopedia of Clinical Neuropsychology. Springer New York, 2011. http://dx.doi.org/10.1007/978-0-387-79948-3_3086.

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Conference papers on the topic "LP shunt"

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Cha, Hun, Yoo Seok Song, Kyu Jong Kim, Jung Rae Kim, and Sung Min KIM. "Dynamic Simulation of a HRSG System for a Given Start-Up/Shut Down Curve." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62468.

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An inappropriate design of HRSG (Heat Recovery Steam Generator) may lead to mechanical problems including the fatigue failure caused by rapid load change such as operating trip, start-up or shut down. The performance of HRSG with dynamic analysis should be investigated in case of start-up or shutdown. In this study, dynamic analysis for the HRSG system was carried out by commercial software. The HRSG system was modeled with HP, IP, LP evaporator, duct burner, superheater, reheater and economizer. The main variables for the analysis were the temperature and mass flow rate from gas turbine and fuel flow rate of duct burner for given start-up (cold/warm/hot) and shutdown curve. The results showed that the exhaust gas condition of gas turbine and fuel flow rate of duct burner were main factors controlling the performance of HRSG such as flow rate and temperature of main steam from final superheater and pressure of HP drum. The time delay at the change of steam temperature between gas turbine exhaust gas and HP steam was within 2 minutes at any analysis cases.
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Liu, Kaiwen, Alejandro Beltran, Serene Gao, and Andrew Greig. "Guidelines to Develop Fitness-for-Service Assessment of Exposed Pipeline Due to Flood Events: Investigation, Assessment and Mitigation." In 2022 14th International Pipeline Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/ipc2022-87778.

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Abstract Over the course of the British Columbia (BC)/ Washington State (WA) flood event, the pipeline restart preparation required a significant, sustained effort to complete a detailed assessment of the pipe’s integrity. Trans Mountain Corporation was able to develop a detailed Fitness-For-Service (FFS) assessment for the exposed pipe segments due to the flood and gain approval from the CER (Canada Energy Regulator) for a successful pipeline restart. On the evening of November 14, 2021, the Trans Mountain Pipeline LP (Trans Mountain) pipeline was shut down as a precautionary measure in response to an ongoing extreme rainfall event. There were multiple sites identified as critical pipe exposures where the pipeline was exposed and unsupported, or experienced mechanical damage, due to soil wash out. All confirmed exposure sites were reported to the CER and Trans Mountain responded in-field to support and protect the pipeline from flowing water, complete pipe inspections, determine the pipe’s FFS, and complete the required repairs before pipeline restart. This paper provides a summary of the FFS assessment that Trans Mountain completed to ensure the integrity of its oil pipeline system after the significant geotechnical event, and the process followed to develop the long-term integrity plans.
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Logar, Andreas, Thomas Depolt, and Edwin Gobrecht. "Advanced Steam Turbine Bypass Valve Design for Flexible Power Plants." In 2002 International Joint Power Generation Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/ijpgc2002-26071.

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The authors company has had extensive experience providing steam turbines including auxiliary systems as a turn key contractor for more than 40 years. Bypass systems are an integrated part of modern Combined Cycle Power Plants (CCPP) [1]. Bypass systems contribute a major part for operational flexibility. They allow the shortest start-up times by minimising mismatches between boiler/HRSG and turbine. Bypass systems also lead to predictable and repeatable start-up times, as well as reducing solid particle erosion of component, to a great extent. The functional requirements for bypass valves are: • Control mode for an accurate control of the IP and LP bypass steam flow during the unit start-up and shut-down, as well as during normal operating transients. • Fast closing mode for bypass-trip (supported by spring force) when required for condenser protection. • Combined mode for fast reaction on pressure increase to a define set point and further action in control mode. In the past, a combined stop and control valve design, each with a separate stem, was common. The challenging objective for the bypass valve design was to integrate the control function and the trip function with a single stem design. The authors company has developed this advanced steam turbine bypass valve that incorporates hydraulic actuator with a single stem design. The valve bodies have noise reduction fittings and are equipped with large extensions on the outlet side to reduce vibration throughout the bypass system. The bypass valve body has an integrated steam strainer which protects both valve parts and the condenser from external debris. The bypass design is prepared for Power Plants with elevated temperatures which allow for the highest plant efficiencies [2]. Surface coating protect moving components against oxidation and reduce friction by means of a surface coating. Steam at high temperature passes through the bypass to the condenser. An incorporated water attemporating flow control system reduces the steam temperatures before entering the condenser. Condensate water is injected through an orifice in the bypass system. The orifice is located down stream in the pipe between the bypass valve and condenser. Electro-hydraulic supply units deliver the control fluid to the bypass valves. An optimized bypass system has to provide: • Long service life with low maintenance costs; • High stroke speed; • Pressure control by unit set point; • High actuation forces; • Accurate positioning; • Very short trip time into closed position. By means of bypass station, one can get highest flexibility of power plants use of the new valve one will get highest control performance and shortest reaction time.
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