Temporary Diversion Research Articles

Temporary Flow Diversion in Oncological Embolization Procedures Using Degradable Starch Microspheres

Objectives: This study aims to report on the application of degradable starch microspheres to provide flow diversion by means of temporary embolization of healthy tissues in oncological endovascular procedures when tumor feeding vessels are not selectively accessible. Methods: This is a multicenter retrospective analysis of patients undergoing visceral embolization procedures of malignancies. The inclusion criteria were as follows: flow diversion performed by injection of degradable starch microspheres, visceral embolization procedures with unfeasible superselective catheterism of the target, and a malignant pathology. Technical success was defined as complete flow diversion with temporary exclusion of the non-target district from arterial flow, associated with successful embolization of the target. Clinical success was intended as procedural achievement with patient clinical improvement. Results: Sixteen patients were included in this analysis. Peripheral embolization procedures were performed in the coeliac visceral district all in oncologic patients, including 4 transarterial radioembolization work-up procedures in patients with hepatocarcinoma, 10 chemioembolization procedures in patients with hepatocarcinoma (8) or cholangiocarcinoma (2), and 2 palliative transarterial embolizations in patients with gastric cancer. Technical success was obtained in 100% of the cases, while clinical success was reached in 87.5%: in two chemioembolization procedures, despite technical success, the procedural clinical benefits were partial, with an incomplete target lesion response. Minor complications occurred in five patients (31.2%). Conclusions: In this study, temporary flow diversion with degradable starch microspheres during oncological embolization procedures was safe and effective; this approach is suitable to protect healthy surrounding tissues when vessels feeding the target cannot be selected with the microcatheter.

High intracranial pressure following endoscopic third ventriculostomy: illustrative case.

Endoscopic third ventriculostomy (ETV) is an effective procedure for the treatment of triventriculomegaly associated with aqueductal stenosis. However, some patients can develop severe and symptomatic intracranial pressure (ICP) elevations in the immediate postoperative period that can be monitored and treated with external ventricular drain (EVD) placement and controlled cerebrospinal fluid (CSF) diversion until the ICP normalizes and symptoms resolve. The authors describe the case of a 39-year-old male who underwent ETV and intraoperative EVD placement for obstructive hydrocephalus associated with aqueductal stenosis. The patient was noted to have sustained ICP elevations in the immediate perioperative period but ultimately experienced a successful clinical outcome without requiring a ventriculoperitoneal shunt. Significant sustained ICP elevations in the immediate postoperative period following ETV can occur and may indicate a prolonged adjustment period. These elevations can be tolerated if the patient's symptoms and ICP are well controlled, with temporary external CSF diversion if the patient becomes symptomatic, as the ICP will likely normalize with a reassuring clinical outcome. https://thejns.org/doi/10.3171/CASE24478.

Congenital Anterior Urethral Obstruction: A Case Series

Congenital Anterior Urethral Diverticulum (CAUD) and Anterior Urethral Valve (AUV) are rare but well-described causes of urinary obstruction in male children. The clinical presentation can range from isolated poor urinary stream with normal bladder and upper tracts to severe obstructive uropathy with renal failure. In the present case series, six children with anterior urethral obstruction managed between June 2014 and June 2024 were retrospectively identified. Age at presentation, clinical features, investigations, management and long-term follow-up were studied. The age at presentation ranged from newborn to seven years. Severe disease, as evidenced by progressive renal failure, was present in 1 of the 6 children (16.6%). One child had undergone foetal intervention by valve ablation but had progressive renal failure on follow-up. Three children (50%) underwent diverticulum excision with urethroplasty, of which one child developed a postoperative urethrocutaneous fistula. One child with AUV had a dorsal urethral fold causing obstruction, unlike the ventral pathology observed in the other children. CAUD and AUV are rare yet important causes of obstructive uropathy. Careful assessment is crucial for making the correct diagnosis. Temporary diversion may be essential when cystoscopy or primary repair is not feasible or in cases of urosepsis.

A COMPARATIVE STUDY ON THE OUTCOME OF ILEOSTOMY VERSUS COLOSTOMY FOR TEMPORARY DIVERSION OF RECTAL ANASTOMOSIS

Temporary diversion with a stoma is often required in patients undergoing rectal resection for rectal cancer to minimize anastomotic complications. Loop ileostomy and loop colostomy are the two common options for fecal diversion. Despite their widespread use, the comparative outcomes regarding morbidity and complications of these procedures, especially in the context of temporary diversion, remain debatable. Objective: To compare the outcomes of loop ileostomy and loop colostomy for temporary rectal diversion in cancer patients undergoing rectal resection. Methods: A prospective study was conducted in the General Surgery Department of Nishtar Hospital, Multan from June 2024 to November 2024. A total of 150 rectal cancer patients undergoing anterior resection were included in the study. Patients were divided into two groups; Group A included 75 patients undergoing loop ileostomy and Group B included 75 patients undergoing loop colostomy. The primary outcome was to perform a comparison between morbidity outcomes after stoma formation and closure between both procedures. Patients were followed up after every 2-4 weeks in OPD after stomal construction and reversal. Results: After stomal construction, the incidence of complications between both groups was similar. Overall morbidity occurred in 23 patients (30.6%) in group A and 21 patients (28%) in group B. The parastomal hernia was the most common complication in the study population in 31 patients (20.6%), the difference in both groups was insignificant (20% vs 21.3%) (p=0.78). After the stomal reversal, 4 (8%) in group A and 1 (1.9%) in group B had anastomotic leaks, however, the difference was insignificant (p=0.19). 50 (66.7%) patients in the ileostomy group and 51 (68%) patients in the colostomy group underwent stoma reversal. Complications after reversal were similar with the most common complication being wound infection (14 vs 7.9%) (p=0.53%). Conclusion: The outcomes of loop ileostomy and loop colostomy for temporary diversion of rectal anastomosis in patients with rectal cancer were comparable. Larger, randomized studies are needed to verify our findings.

The Development of a Hydrological Method for Computing Extreme Hydrographs in Engineering Dam Projects

Engineering dam projects benefit society, including hydropower, water supply, agriculture, and flood control. During the planning stage, it is crucial to calculate extreme hydrographs associated with different return periods for spillways and diversion structures (such as tunnels, conduits, temporary diversions, multiple-stage diversions, and cofferdams). In many countries, spillways have return periods ranging from 1000 to 10,000 years, while diversion structures are designed with shorter return periods. This study introduces a hydrological method based on data from large rivers which can be used to compute extreme hydrographs for different return periods in engineering dam projects. The proposed model relies solely on frequency analysis data of peak flow, base flow, and water volume for various return periods, along with recorded maximum hydrographs, to compute design hydrographs associated with different return periods. The proposed method is applied to the El Quimbo Hydropower Plant in Colombia, which has a drainage area of 6832 km2. The results demonstrate that this method effectively captures peak flows and evaluates hydrograph volumes and base flows associated with different return periods, as a Root Mean Square Error of 11.9% of the maximum volume for various return periods was achieved during the validation stage of the proposed model. A comprehensive comparison with the rainfall–runoff method is also provided to evaluate the relative magnitudes of the various variables analysed, ensuring a thorough and reliable assessment of the proposed method.

The effect of urinary diversion on kidney function in posterior urethral valves and ureterovesical obstruction.

Posterior urethral valves (PUV) and ureterovesical junction obstruction (UVJO) are common etiologies of lower urinary tract obstruction. The primary objective of therapy is to alleviate the obstruction in the urinary system. Temporary urinary diversion may be necessary in certain situations, such as Urinary tract infection (UTI), sepsis, and unchanging hydronephrosis. This study, aims to assess kidney parameters after urinary diversion (either pyelostomy or ureterostomy) in patients with PUV and UVJO. We conducted a retrospective analysis of all patients diagnosed with PUV or UVJO and treated with urinary diversion following urinary undiversion at our facility between 2015 and 2020. The following variables were collected: demographic details, surgical interventions (type of diversion), serum creatinine throughout follow-up, anterior-posterior diameter of the pelvis (APP), anterior-posterior diameter of the ureter (APU), and sonographic findings of renal parenchymal thickness (PT) as documented by a pediatric radiologist. Additionally, before and after urinary diversion, a Dimercapto succinic acid (DMSA) nuclear renal scan was conducted to assess renal function. We analyzed 67 patients, with a mean follow-up of 38.3months, undergoing either ureterostomy (42 patients) or pyelostomy (25 patients). This included 38 patients with PUV and 29 with UVJO. In PUV patients, significant improvements were observed in APP (MD = 5.56 ± 11.6, p = 0.0194), APU (MD = 5.57 ± 7.28, p < 0.001), and PT (MD = 3.66 ± 2.75, p < 0.001). Similarly, UVJO patients experienced significant improvements in APP (MD = 12.18 ± 18.63, p = 0.005), APU (MD = 7.82 ± 8.98, p = 0.001), and PT (MD = 2.79 ± 3.33, p = 0.001). DMSA scores did not significantly change in either group (p > 0.05). Notably, APP improved more in UVJO patients compared to PUV patients (p = 0.047). Our study suggests that urinary diversion could improve APP, APU, and renal parenchymal thickness in PUV and UVJO patients. The improvement of APP in UVJO patients was greater than in the PUV group. We propose further multi-center studies with longer durations of follow-up and more detailed additional data to support and confirm our results.

Discontinuation of Cerebro-Spinal Fluid (CSF) Drainage in Acute Hydrocephalus: A Prospective Cohort Study and Exploratory Data Analysis.

The optimal management of CSF drainage in acute hydrocephalus, in particular when to initiate drain weaning, remains uncertain. This study aimed to evaluate the impact of timing and method of drain weaning on patient outcomes. This prospective observational study in a large-volume tertiary neuroscience centre included all adult patients who required temporary CSF drainage for acute hydrocephalus of any cause between January 2020 and March 2021. Contemporaneous data collection was conducted, including patient demographics, time to clamp, weaning methods, and clinical outcomes of hospital length of stay (LOS), rate of shunt insertion, drain-related infections, and mechanical complications. Univariate and multivariate statistical analyses were performed to identify the independent associations of timing-related factors. A total of 69 patients were included (mean age = 59.4 years). A total of 59% had CSF diversion for aneurysmal subarachnoid haemorrhage, and 88% had EVD drainage. The length of drainage prior to the first clamp was significantly associated with the overall length of drainage (p < 0.0001), LOS (p = 0.004), and time to shunt (p = 0.02) following multivariate adjustment. For each day delayed in initiating the drain challenge, the overall LOS increased by an additional 1.25 days. There was no association between the weaning method and LOS, the rate of shunting, or CNS infection; however, those in the gradually weaned group had more mechanical complications, such as drain blockage or CSF leakage, than those rapidly weaned (p = 0.03) after adjustment. This study recommends challenging the drain early via a rapid wean to reduce LOS, mechanical complications, and possibly infections. The consequences of temporary CSF diversion have significant implications at financial and patient levels, but the quality of evidence regarding weaning remains poor. Further randomised multicentre studies and national databases of practice are required to allow definitive conclusions to be drawn.

Application effect of temporary plugging and diverting fracturing technology in well X1

Abstract The deployment of horizontal well development in the sweet spot area of the main sand body can improve the reservoir control degree and the production of a single well. The X1 well in the X block will be put into production after fracturing in 2022. The target layer of this well is a tight reservoir with low porosity and low permeability, and natural fractures are not developed. Combined with the geological characteristics of the target well, horizontal well soluble bridge plug and temporary plugging and diversion fracturing technology are applied to well X1, and branch fractures are formed through temporary plugging and diversion in the fracture, which increases the complexity of fractures and increases the drainage area. The well is currently in production for 485 days, with a peak oil day of 17.4t and a current oil day of 7t, with a cumulative oil production of 4184.6t. In this paper, the fracturing effect of well X1 is preliminatively analyzed, and it is concluded that under the same reservoir conditions, the single particle size sand combined with temporary plugging in the fracture transformation has a relatively good development effect, which can obviously improve the development effect of tight reservoir. The application effect of soluble bridge plug and temporary plugging diversion fracturing technology in this well has certain reference significance for improving the development effect and benefit of horizontal well in ultra-low permeability reservoir.

Comparison between Different Temporary Measures for Management of Post- Hemorrhagic Hydrocephalus in Premature Infants: A Systematic Review

Abstract Background Germinal matrix hemorrhage and subsequent posthemorrhagic hydrocephalus are common among pre-term infants due to multiple factors including fragility of germinal matrix vasculature, swinging increases of arterial and venous pressure, periodic hypoxia, and high metabolic demand. Aim of the Work To compare between Ventricular access device (VAD) and Neuroendoscopic lavage (NEL) as temporary measures for management of posthemorrhagic hydrocephalus in premature infants in terms of incidence of permanent shunt placement, and post operative complications like infection. This will be done through a systematic review of literatures addressing this research question. Patients and Methods Our study included 13 observational studies (12 retrospective and 1 prospective) comparing ventricular access device insertion vs neuroendoscopic lavage in management of posthemorrhagic hydrocephalus in pre-term infants regarding the need for VP shunt insertion and post operative complications mainly post operative infection and malfunction of the temporary CSF diversion, most of the cases had germinal matrix hemorrhage G III-IV according to papille classification, the results showed that while the neuroendoscopic lavage group had lower rate of VP shunt insertion, they had higher rate of post operative complications mainly malfunction of CSF diversion (The incidence of post operative infection was similar in both groups). Results In this review while comparing the need for VP shunt insertion in both groups was somewhat simple, comparing complications on the other hand was problematic due to the heterogenicity between types of complications and the underlying comorbidities, with different follow up periods and most of the complications is not shared by both groups. Conclusion Based on our systematic review and other available data in the literature, the neuroendoscopic lavage may be the preferred intervention for management of posthemorrhagic hydrocephalus in preterm infants regarding the incidence of permanent VP shunt insertion, although it has higher rate of malfunction and no statistical difference in post operative infection compared with the ventricular access device group.

Research and Application of Temporary Blocking and Diversion Techniques for Fractures in Tight Oil Reservoirs

Research and Application of Temporary Blocking and Diversion Techniques for Fractures in Tight Oil Reservoirs

Application of Low-Temperature Temporary Plugging Agents in Coalbed Methane Volume Fracturing

Currently, unconventional oil and gas fields employ volume fracturing technology, and temporary plugging and diversion techniques have become one of the main methods for increasing production. The Mixi coalbed methane block in Yibing has a formation vertical depth of 800-1000 meters and a relatively low average formation temperature of 30 degrees Celsius. The temporary plugging agents currently in use face challenges during reservoir stimulation, including difficulty in withstanding pressure differentials, poor degradability, and significant reservoir damage, resulting in unsatisfactory implementation effects. Therefore, the water-soluble temporary plugging agent RD-1 was selected as the preferred option. Laboratory performance evaluation experiments have demonstrated that this temporary plugging agent exhibits good sealing and degradation properties. Field trials have shown good temporary plugging and diversion effects, with noticeable pressure increase during plugging and significantly improved stimulation volume. It has demonstrated good applicability in coalbed methane volume fracturing, accumulating valuable experience for efficient development of this block.

Temporary diverting loop ileostomy in Crohn's disease surgery; indications and outcome.

Crohn's disease can present with complex surgical pathologies, posing a significant risk of morbidity and mortality for patients. The implementation of a loop ileostomy for selected patients may help minimize associated risks. In this retrospective cohort study, we investigated the utilization of temporary fecal diversion through the creation of a loop ileostomy in Crohn's surgery. Closure of all ostomies involved a hand-sewn single-layer technique. We then conducted bivariate analysis on 30-day outcomes for closures, focusing on favorable recovery defined as the restoration of bowel continuity without the occurrence of two challenges in recovery: newly developed organ dysfunction or the necessity for reoperation. In total, 168 patients were included. The median age of the patients was 38 years (IQR 27-51). The most common indication for a loop ostomy was peritonitis (49%). After ileostomy closure, 163 patients (97%) achieved favorable recovery, while five encountered challenges; four (2.4%) underwent abdominal surgery, and one (0.6%) developed acute renal failure requiring dialysis. Two patients (1.2%) had a re-creation of ileostomy. Patients encountering challenges were older (56 [IQR 41-61] vs. 37 [IQR 27-50]; p 0.039) and more often required secondary intention wound healing (40% vs. 6.7%; p 0.049) and postoperative parenteral nutrition following their index surgery (83% vs. 26%; p 0.006). Selectively staging the Crohn's disease operations with a loop ileostomy is a reliable practice with low morbidity and high restoration rates of bowel continuity. Our hand-sewn single-layer technique proves effective in achieving successful surgical recovery.

Autologous blood urethral patching: A novel treatment option for persistent urethral leakage in a dog

AbstractA 6‐year‐old miniature schnauzer was referred for urolithiasis and perineal swelling, suspicious of urethral trauma. On positive‐contrast cystourethrogram, the dog was diagnosed with rupture of the penile urethra. Temporary urinary diversion was attempted with no improvement. Primary urethral anastomosis was performed, but urine leakage resumed after surgery and led to wound formation in the perineum. Additional surgery was recommended to repair the urethra, but financial constraints prevented further surgery and hospitalisation. The decision was made to attempt an autologous blood urethral patch, mimicking the methodology of autologous blood pleurodesis for persistent pneumothorax. Autologous blood was instilled into the urethra at the site of the urethral tear. Five days after the procedure was performed, positive‐contrast cystourethrogram identified no contrast material outside the boundaries of the urethra. In this dog, performing autologous blood urethral patch resulted in a safe and non‐invasive treatment option for persistent urethral leakage following failure of traditional management.

The Formation and Pressure-Bearing Characteristics of Plugging Layers in Hydraulic Fracture: A Visualization Experimental Study

Summary Temporary plugging and diversion fracturing (TPDF) is an important means for improving the artificial fracture complexity in shale gas reservoirs. At present, most scholars’ studies on TPDF mainly focus on the formation conditions of the plugging layer in a horizontal fracture and the fracture propagation behavior after the plugging layer is formed. However, there is a lack of thorough study on the formation and pressure-bearing characteristics of the plugging layer in vertical fracture. For this paper, we conducted a plugging experiment using temporary plugging particles in a hydraulic fracture by use of a visualization hydraulic fracture experimental device to analyze the formation and pressure-bearing characteristics of plugging layers. The research results show that (1) when the ratio of temporary plugging particle diameter to fracture width (d/w) becomes larger, the fluid viscosity and injection rate have less influence on the formation of the plugging layer, and the concentration of temporary plugging particles required to form the plugging layer decreases. When d/w is equal to 0.45, the plugging layer has difficulty forming if the fluid viscosity is greater than 3 mPa·s or the mass concentration of temporary plugging particles is less than 20 kg/m3. If d/w is equal to 0.60, the plugging layer has difficulty forming when the concentration is less than 10 kg/m3. When d/w is equal to 0.75, a plugging layer forms when the concentration is 2.5 kg/m3, and the formation is not affected by the fluid viscosity and injection rate. (2) A smaller d/w, higher carrier fluid viscosity and injection rate, or lower temporary plugging particle concentration all lead to more pronounced fluctuation of the fracture flow channels at the location where the plugging layer is formed. (3) If the plugging layer can form, it is denser and has stronger plugging ability when the temporary plugging particle diameter is smaller and fluid viscosity and injection rate are larger. (4) Due to different lengths and d/w, the plugging layer can be divided into three types according to its morphological change characteristics after pressure-bearing: failure-unstable, locally-damaged, and stable-unchanged plugging layer. To improve the probability of forming the plugging layer with higher stability, the fluid with a viscosity of 3 mPa·s, in which is a temporary plugging particle with a d/w of 0.75, is recommended to plug the hydraulic fractures under an injection rate of 0.65 m3/min.

Management of the child with refractory constipation.

Caring for children with constipation refractory to conventional treatment can be challenging and management practices vary widely. To review recent advances in the evaluation and treatment of children with refractory constipation and to propose an algorithm that incorporates the latest evidence and our institutional experience. We performed a literature review on diagnostic tests and treatment options for children with refractory constipation. Evaluation of a child with refractory constipation seeks to better understand factors contributing to an individual child's presentation. Anorectal manometry evaluating for a rectal evacuation disorder and colonic manometry evaluating for colonic dysmotility can guide subsequent treatment. For the child who has not responded to conventional treatment, a trial of newer medications like linaclotide can be helpful. Transanal irrigation offers a safe and effective alternative for families able to administer daily rectal treatment. Despite mixed evidence in children, pelvic floor biofeedback therapy can help some children with pelvic floor dyssynergia. For younger children unable to cooperate with pelvic floor therapy, or older children with refractory symptoms, internal anal sphincter botulinum toxin injection can be beneficial. Antegrade continence enema treatment can be effective for children with either normal colonic motility or segmental dysmotility. Sacral nerve stimulation is generally reserved for symptoms that persist despite antegrade continence enemas, particularly if faecal incontinence is prominent. In more severe cases, temporary or permanent colonic diversion and segmental colonic resection may be needed. Recent advances offer hope for children with refractory constipation.

Postoperative Crohn's Disease Recurrence Risk and Optimal Biologic Timing After Temporary Diversion Following Ileocolic Resection.

Postoperative recurrence of Crohn's disease (CD) is common. While most patients undergo resection with undiverted anastomosis (UA), some individuals also have creation of an intended temporary diversion (ITD) with an ileostomy followed by ostomy takedown (OT) due to increased risk of anastomotic complications. We assessed the association of diversion with subsequent CD recurrence risk and the influence of biologic prophylaxis timing to prevent recurrence in this population. This was a retrospective cohort study of CD patients who underwent ileocolic resection between 2009 and 2020 at a large quaternary health system. Patients were grouped by continuity status after index resection (primary anastomosis or ITD). The outcomes of the study were radiographic, endoscopic, and surgical recurrence as well as composite recurrence postoperatively (after OT in the ITD group). Propensity score-weighted matching was performed based on risk factors for diversion and recurrence. Multivariable regression and a Cox proportional hazards model adjusting for recurrence risk factors were used to assess association with outcomes. Subgroup analysis in the ITD group was performed to assess the impact of biologic timing relative to OT (no biologic, biologic before OT, after OT) on composite recurrence. A total of 793 CD patients were included (mean age 38 years, body mass index 23.7kg/m2, 52% female, 23% active smoker, 50% penetrating disease). Primary anastomosiswas performed in 67.5% (n = 535) and ITD in 32.5% (n = 258; 79% loop, 21% end) of patients. Diverted patients were more likely to have been males and to have had penetrating and perianal disease, prior biologic use, lower body mass index, and lower preoperative hemoglobin and albumin (all P < .01). After a median follow-up of 44 months, postoperative recurrence was identified in 83.3% patients (radiographic 40.4%, endoscopic 39.5%, surgical 13.3%). After propensity score matching and adjusting for recurrence risk factors, no significant differences were seen between continuity groups in radiographic (adjusted hazard ratio [aHR], 1.32; 95% confidence interval [CI], 0.91-1.91) or endoscopic recurrence (aHR, 1.196; 95% CI, 0.84-1.73), but an increased risk of surgical recurrence was noted in the ITD group (aHR, 1.61; 95% CI, 1.02-2.54). Most (56.1%) ITD patients started biologic prophylaxis after OT, 11.4% before OT, and 32.4% had no postoperative biologic prophylaxis. Biologic prophylaxis in ITD was associated with younger age (P < .001), perianal disease (P = .04), and prior biologic use (P < .001) but not in recurrence (P = .12). Despite higher rates of objective disease activity identified before OT, biologic exposure before OT was not associated with a significant reduction in composite post-OT recurrence compared with starting a biologic after OT (52% vs 70.7%; P = 0.09). Diversion of an ileocolic resection is not consistently associated with a risk of postoperative recurrence and should be performed when clinically appropriate. Patients requiring diversion at time of ileocolic resection are at high risk for recurrence, and biologic initiation prior to stoma reversal may be considered.

Rectal Injury During Penile Inversion Vaginoplasty

ObjectiveTo evaluate the incidence, management and outcomes of rectal injury (RI) and subsequent rectovaginal fistula (RVF) during gender-affirming vaginoplasty (GAV) at a high-volume transgender surgery center. MethodsWe performed a retrospective review of pre-operative, intra-operative and post-operative findings of all patients with RI during GAV from January 2016-September 2022. Descriptive statistics were calculated using Microsoft Excel. ResultsRI occurred in nine of 1011 primary GAV and colorectal surgery (CRS) consulted in five cases, which included sigmoidoscopy with an air leak test in four and with temporary bowel diversion in two. Of the nine, six proceeded with full depth GAV, and three were converted to minimal depth vaginoplasty. Two had bulbospongiosus muscle interposition and none had a concomitant urethral injury. 1/9 with RI developed a RVF which occurred in a patient with prior perineal surgery and no intraoperative sigmoidoscopy. Three (50%) with full depth GAV developed vaginal stenosis postoperatively. ConclusionsRI during primary GAS in experienced hands is uncommon with an incidence of 0.89% in our series of 1011. Unusual tissue dissection planes were a risk factor. If injuries were identified intraoperatively, repaired with multilayer closure and evaluated by CRS, patients did well without the development of RVF despite completion of full depth GAV. It is reasonable to complete the full depth vagina, but patients should be advised of a significant risk of post-operative vaginal stenosis.

Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation

This study conducted temporary plugging and diversion fracturing (TPDF) experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation. The effects of temporary plugging agent (TPA) particle size, TPA concentration, single-cluster perforation number and cluster number on plugging pressure, multi-fracture diversion pattern and distribution of TPAs were investigated. A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures. The addition of fibers can quickly achieve ultra-high pressure, but it may lead to longitudinal fractures extending along the wellbore. The temporary plugging peak pressure increases with an increase in the concentration of the TPA, reaching a peak at a certain concentration, and further increases do not significantly improve the temporary plugging peak pressure. The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number. A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure, and it has a more significant control on the propagation of multi-cluster fractures. A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures, while a higher number of clusters makes it difficult to achieve effective plugging. The TPAs within the fracture is mainly concentrated in the complex fracture areas, especially at the intersections of fractures. Meanwhile, the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures.

An Interdisciplinary Protocol for Ventriculoperitoneal Shunt Patient Selection in Normal Pressure Hydrocephalus

BackgroundNormal pressure hydrocephalus (NPH) can be treated with ventriculoperitoneal shunt (VPS) placement, but no broadly implemented indication for VPS exists. MethodsOur protocol consists of physical therapy and occupational therapy practitioners administering validated tests of gait, balance, and cognition before and after lumbar drain (LD) placement. Specific tests include: Timed “Up & Go”, Tinetti Gait and Balance Assessment, Berg Balance Scale, Mini Mental Status Exam, Trail Making Test Part B, and the Rey Auditory and Visual Learning Test. Minimal clinically important difference values for each test were determined from literature review. A retrospective review of patients treated under this protocol was performed. The primary outcomes were candidacy for VPS based on the protocol and patient-reported symptomatic improvement after VPS placement. Results48/75 (64%) patients received VPS. 43/48 (89.6%) of those shunted reported improved symptoms at 6 week follow up. However, 10/22 (45.5%) reported worsening symptoms at 1 year follow up. The mean Tinetti score significantly increased after LD in patients who improved with VPS compared to the no shunt group (4.27 vs -0.48, p<0.001). 6/33 (18%) patients with post-op imaging had a subdural fluid collection identified and 3/49 (6%) had other complications, including 1 seizure, 1 intracerebral hemorrhage, and 1 stroke. ConclusionsStandardized assessment of gait, balance, and cognition before and after temporary CSF diversion identifies patients with NPH likely to benefit from VPS placement with a low complication rate. One year after VPS, approximately half of patients had symptoms recur.

Development and field application of strongly resilient temporary plugging diversion agent for fracturing

Temporary plugging diversion fracturing in multistage horizontal well is normally used to improve stimulation efficiency and increase production in unconventional reservoirs. Temporary plugging agent plays an important role in diversion fracturing. A strongly resilient temporary plugging diversion agent can improve the effectiveness of fracturing diversion. Therefore, a novel organosilicon temporary plugging diversion agent (QBZU) was developed through micellar copolymerization method. Self-synthesized strongly resilient temporary plugging diversion agent (QBZU gel) was prepared by using acrylamide, N, N′-methylene bisacrylamide, surfactants, organosilicon, ammonium persulfate and sodium bisulfite as chemical raw materials. The micellar copolymerization is investigated to overcome the incompatibility of hydrophobic organosilicon and water-soluble monomer by adding some appropriate surfactants. The experimental results indicated that the combination of sodium dodecyl sulphonate and Tween 80 provided excellent copolymerization results. The characteristics of compressive resistance, salt resistance, shearing resistance, resilience and degradation are superior compared with traditional rigid granular temporary plugging agent widely used in oilfields (QG hydrogel). According to the experimental evaluation results of QBZU, its pressure-bearing capacity can reach 56.3MPa, shearing strength can reach 410N, elastic modulus can reach 80MPa, and Poisson ratio can reach 0.48. Meanwhile, the main synthetic factors affecting the resilient performance of QBZU were investigated, including polymer concentration, organosilicon concentration and the types of surfactant. Based on the fracturing pressure curve and microseismic monitoring results, the plugging and fracture diversion effectiveness was further confirmed.