In vitro quantification of stent-graft behaviour during chimney thoracic endovascular aortic repair.

OBJECTIVE: To quantify dynamic gutter phenomena and endograft deformations during double chimney thoracic endovascular aortic repair (ch-TEVAR) in a physiological model of the thoracic aorta subjected to pulsatile haemodynamic conditions. METHODS: Two in vitro procedures revascularizing the brachiocephalic trunk and left common carotid artery were performed representing both balloon-expandable (BE, Ankura-BeGraft) and self-expandable (SE, Ankura-Viabahn) double ch-TEVAR configurations. Retrospectively gated computed tomography (CT) was used to evaluate endograft behaviour. Device interactions were characterised according to gutter volume, gutter surface deviation, and endograft deformation (D-ratio) at end-diastolic and peak-systolic aortic pressure. RESULTS: Use of BE chimney grafts resulted in three times total gutter volume compared to SE chimney grafts. Gutter volumes were observed to vary dynamically between the end-diastolic and peak-systolic phases of the cardiac cycle, with the most substantial change associated with the BE configuration. Chimney graft deformations were dependent on device type, with SE devices exhibiting up to twice the deformation as BE devices. When adjacent, SE chimney grafts were observed to support each other, and thus tended towards a more consistently circular shape. CONCLUSION: Gutter and chimney graft behaviour were dependent on device type, and exhibited both spatial and temporal variability. This study emphasises notable differences between BE and SE double ch-TEVAR configurations which should be considered when evaluating risk of endoleak. The findings reported here also support the use of gated CT to better identify device-related complications with ch-TEVAR, and can be used in the design of next generation devices.

What we have learned from in-vitro studies of the chimney endovascular technique for treatment of complex abdominal aortic aneurysms: A systematic review.

BACKGROUND: A considerable number of patients with abdominal aortic aneurysms (AAA) is not eligible for standard endovascular repair. These complex cases require alternative surgical approaches including the readily available chimney graft endovascular aneurysm repair (Ch-EVAR) or sealing (Ch-EVAS). The optimal configuration for Ch-EVAR or Ch-EVAS is important for success but not yet known. OBJECTIVE: The aim of the present study was to analyze current data of the outcomes of in-vitro chimney graft treatment in complex AAA. METHODS: A systematic review following PRISMA guidelines was conducted including studies reporting on gutter size, main graft compression, and chimney graft compression in in-vitro configurations. RESULTS: The search resulted in 285 articles. 11 studies considering 219 individual tests could be included. Gutter size was comparable between Ch-EVAR and Ch-EVAS configurations. In Ch-EVAR set-ups, the deployed BECG were Advanta V12, VIABAHN®, and BeGraft. One type of SECG was used: VIABAHN®. The four types of main grafts (MG) deployed were: Endurant™ I/II; EXCLUDER Conformable AAA Endoprosthesis and AAA Endoprosthesis, and AFX™ Endovascular AAA Delivery System. In the EVAS-configurations, the Nellix® EVAS system was deployed. In general, SECG presented smaller gutters with higher chimney graft compression. 30% main grafts oversizing seems to give the smallest gutters without high risk of infolding of MG. Oversizing, EndoAnchors, and secondary endobag filling (in Ch-EVAS) reduced gutter sizes. CG ballooning during the entire polymer injection in Ch-EVAS prevented CG compression. CONCLUSION: In-vitro investigations provide insight in optimal Ch-EVAR and Ch-EVAS configurations for simulated complex AAA repair. The findings above might aid physicians in their planning to potential CG set-ups and can be used in future research to refine the most optimal configuration for chimney graft technique in complex AAA.

Curbing sediment: The effects of added surface roughness in the curb and gutter as a novel pretreatment for green infrastructure stormwater control measures.

Stormwater control measures (SCMs) are employed to reduce the multitude of deleterious impacts of urban runoff on receiving waters. Sediment accumulation in infiltration-based SCMs can clog these systems, resulting in lack of hydraulic function and reduced stormwater treatment efficacy. As such, pretreatment devices, such as forebays, filter strips, or catch basin sumps, are typically employed upstream of SCMs to remove sediment and prolong maintenance intervals. However, the tendency of SCMs to be retrofitted into space-constrained, ultra-urban areas makes including pretreatment technologies difficult. An alternative pretreatment device for green infrastructure SCMs was developed and tested in the laboratory; alterations were made to the standard curb and gutter, which is ubiquitous within urban environments, to increase the roughness of these surfaces. Roughness was added to the curb and/or gutter of mock road sections constructed of expanded polystyrene (EPS) foam using a computer numerical control (CNC) router. Twenty-one patterns with varying degrees of depth, shape, and spacing were implemented to trap sediment from simulated runoff; samples were collected upstream and downstream of the added roughness and analyzed for sediment removal and particle capture. Patterns which included added roughness in both the curb and gutter reduced total suspended solids (TSS) concentrations by up to 95% (median 85%) and reduced median d50 and d90 in runoff from 46.9 to 39.4 µm and 322 to 100 µm, respectively. Continued TSS removal was observed during repeated testing designed to simulate up to seven runoff events, indicating the potential for sustained sediment accumulation before the need for maintenance via regular street sweeping. With routine maintenance performed at appropriate intervals, these findings indicate that added roughness to curb and gutters could be utilized as a viable pretreatment technology for green infrastructure SCMs.

Early Results of a Novel Gutter-Free Chimney Stent-Graft System to Treat Aortic Arch Dissection: Single-Center Data from a Prospective Clinical Trial.

AIMS: Discuss the clinical value, technique characteristics, and early follow-up results of a newly designed gutter-free chimney stent-graft system for aortic arch pathology. METHODS AND RESULTS: About 13 patients with aortic arch dissection were enrolled in a clinical trial testing a novel gutter-free stent-graft between February 2019 and December 2020. All 13 patients were male, age 52.6±10.4 years. The implantation time was 14.0±6.9 minutes; total procedure time was 89.5±19.8 minutes. The volume of contrast was 79.6±7.2 ml. And 15 aortic stent-grafts were implanted, and all 13 patients had chimney branch stent-grafts implanted into the left subclavian artery (LSA). There were 3 (23.1%) cases of immediate type Ιa endoleak after thoracic endovascular aortic repair (TEVAR), and 7.7% type Ιa endoleaks occurred in delayed fashion. Survival at 2 years was 100%, and the 2-year patency of chimney stent-grafts was 100%. CONCLUSIONS: This study reports early success with good freedom from endoleak using a novel stent-graft designed for chimney TEVAR to treat aortic arch dissection. Postoperative survival and patency of the branch stent-grafts were excellent. Additional data from this multicenter clinical trial will be forthcoming.

A simple and rapid homogeneous fluorescence polarization immunoassay for rapid identification of gutter cooking oil by detecting capsaicinoids.

In order to address the widespread concerns with food safety such as adulteration and forgery in the edible oil field, this study developed a fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody in a homogeneous solution system for determination of capsaicinoids in gutter cooking oil by using chemically stable capsaicinoids as an adulteration marker. The prepared fluoresceinthiocarbamyl ethylenediamine (EDF) was coupled with capsaicinoid hapten C, and the synthesized tracer was purified by thin-layer chromatography (TLC) and showed good binding to the monoclonal antibody CPC Ab-D8. The effects of concentration of tracer and recognition components, type and pH of buffer and incubation time on the performance of FPIA were studied. The linear range (IC20 to IC80) was 3.97-97.99 ng/mL, and the half maximal inhibitory concentration (IC50) was 19.73 ng/mL, and the limit of detection (LOD) was 1.56 ng/mL. The recovery rates of corn germ oil, soybean oil and peanut blend oil were in the range of 94.7-132.3%. The experimental results showed that the fluorescence polarization detection system could realize the rapid detection of capsaicinoids, and had the potential to realize on-site identification of gutter cooking oil. As a universal monoclonal antibody, CPC Ab-D8 can also specifically identify capsaicin and dihydrocapsaicin, so the proposed method can be used to quickly monitor for the presence of gutter cooking oil in normal cooking oil.

Ring finger metacarpal fracture iatrogenic rotation using an ulnar gutter splint: A cadaveric study.

STUDY DESIGN: Cohort cadaveric study. INTRODUCTION: Ring finger metacarpal fractures are often treated with ulnar gutter orthoses incorporating the ring and small fingers. Iatrogenic pronation of the distal metacarpal fragment may occur from overzealous orthotic "molding", resulting in a crossover deformity of the ring finger over the small finger. PURPOSE OF THE STUDY: The goal of this cadaveric study is to determine whether including the middle finger in an ulnar gutter orthotic could lessen the chances of iatrogenic ring finger metacarpal fracture rotation. METHODS: Transverse ring finger metacarpal shaft fractures were created in 24 cadaver hands. The ring and small fingers were then placed into an intrinsic plus position, simulating the application of an ulnar gutter orthotic. Weights of 2.5, 5, and 10 pounds were applied to the ring and small fingers to simulate iatrogenic-induced fracture pronation. The amount of rotational displacement at the fracture was measured, and the protocol was repeated, including the middle finger in the intrinsic plus position. Mann-Whitney-Wilcoxon test was used for statistical analysis. RESULTS: There was an increase in distal fragment rotation with increasing weight. Fracture displacement was greater with the 2-finger position than the 3-finger at all weight levels; this reached statistical significance at 10 lbs (2.8 vs 1.8 mm). CONCLUSIONS: Application of an ulnar gutter orthotic including only ring and small fingers can rotate the distal fragment of a ring finger metacarpal shaft fracture such that overlap could occur with the small finger. Including the middle finger in ulnar gutter splints will mitigate against the rotation of the ring finger metacarpal shaft fracture.

Mid-term functional outcomes following reoperation after total ankle arthroplasty: A retrospective cohort study.

BACKGROUND: Despite a significant reported rate of non-revision reoperation after total ankle arthroplasty (TAA), it is uncertain if these subsequent procedures have an impact on the longer term outcomes. This study aimed to compare minimum five-year functional outcomes of patients who had undergone reoperation after TAA to those who did not require reoperation. METHODS: Seventy-six ankles (74 patients) who underwent TAA with the Salto Talaris fixed bearing system between 2007 and 2014 were allocated into two groups based on presence (n = 16) or absence of reoperation (n = 60). Reoperations included all secondary procedures after index TAA, excluding revision surgeries requiring removal or exchange of the original prosthesis. The foot and ankle outcome score (FAOS) at preoperative and minimum five-year follow-up was compared between the groups. Additionally, improvements in FAOS subscales were compared. Preoperative deformity, postoperative implant alignment, number of periprosthetic cysts, and subsidence between groups were compared using standard weightbearing radiographs. RESULTS: The most common cause of reoperation was gutter impingement (n = 11), followed by stress fracture of the medial malleolus (n = 2), tarsal tunnel syndrome (n = 1), periprosthetic cyst (n = 1), and infection (n = 1). In comparison to the non-reoperation group, all FAOS subscales except for the Sports and Recreational Activities subscale were significantly lower in the reoperation group at final follow-up. The reoperation group exhibited significantly less improvement in the Pain, Symptoms, and Quality of Life subscales at final follow-up (p < 0.05). There were no statistical differences in the radiographic parameters between both groups. CONCLUSIONS: Patients who underwent reoperation after TAA demonstrated inferior functional outcomes at mid-term follow-up. An emphasis should be placed on preventing possible causes of reoperations to achieve favorable patient outcomes. Additionally, if a reoperation is deemed necessary, a thorough evaluation and surgical correction of underlying causes should be achieved.

Characteristics of medial gutter arthritis on weightbearing CT and plain radiograph.

OBJECTIVE: An ankle arthritis with medial gutter obliteration is known to have good results after joint preservation surgery. However, the diagnosis is often missed on radiographs. The aims of this study were to investigate sensitivity of radiographs in the identification of medial gutter arthritis, incidence and direction of the talar tilt on weightbearing CT (WBCT), and to assess radiographic alignment of the medial gutter arthritis. MATERIALS AND METHODS: Radiographic data was retrospectively evaluated in 102 ankles which were diagnosed medial gutter arthritis by using the WBCT at our clinic between January 2017 and June 2019. Among the 102 ankles, proportion of ankles which showed medial gutter arthritis on plain radiograph was obtained. The presence and direction of talar tilt were assessed on three coronal WBCT images at the anterior, middle, and posterior aspect of the ankle. Plain radiographic parameters were compared between the 102 ankles and control group. RESULTS: Plain radiograph showed medial gutter arthritis only in 63 ankles (62%) among the 102 ankles. Most of the ankles with medial gutter arthritis showed talar tilt on WBCT, and about half of all ankles showed valgus talar tilt at the anterior aspect of ankle on WBCT. In ankles with medial gutter arthritis, the mechanical axis of the lower extremity and the tibial plafond were varus angulated and the talus was medially translated compared to the control group. CONCLUSION: Radiographs were less sensitive than WBCT in demonstrating medial gutter arthritis. Anterior aspect of ankles with medial gutter arthritis often showed valgus direction of talar tilt. Varus mechanical axis deviation and varus tibial plafond are commonly associated with the medial gutter arthritis.

Gutter Characteristics and Stent Compression of Self-Expanding vs Balloon-Expandable Chimney Grafts in Juxtarenal Aneurysm Models.

Purpose: To assess in silicone juxtarenal aneurysm models the gutter characteristics and compression of different types of chimney graft (CG) configurations. Materials and Methods: Fifty-seven combinations of Excluder C3 or Conformable Excluder stent-grafts (23, 26, and 28.5 mm) were deployed in 2 silicone juxtarenal aneurysm models with 3 types of CGs: Viabahn self-expanding (VSE; 6 and 13 mm) or Viabahn balloon-expandable (VBX; 6, 10, and 12 mm) stent-grafts and Advanta V12 balloon-expandable stent-grafts (ABX; 6 and 12 mm). Setups were divided into 4 groups on the basis of increasing CG and main graft (MG) diameters. Two independent observers assessed gutter size and type as well as CG compression on computed tomography scans using postprocessing software. Results: In the smaller diameter combinations (6-mm CG and 23-, 26-, and 28.5-mm MGs), both VSE (p=0.006 to 0.050) and ABX (p=0.045 to 0.050) showed lower gutter areas and volumes compared with VBX. In turn, the VBX showed a nonsignificant tendency to decreased compression, especially compared to ABX. Use of the Excluder C3 showed a 6-fold increase in type A1 gutters (related to type Ia endoleak) as compared to the Conformable Excluder (p=0.018). Balloon-expandable stent-grafts (both ABX and VBX) showed a 3-fold increase in type A1 gutters in comparison with self-expanding stent-grafts (p=0.008). Conclusion: The current study suggests that use of the Conformable Excluder in combination with VSE chimney grafts is superior to the other tested CG/MG combinations in terms of gutter size, gutter type, and CG compression.

Homemade Candy Plug Using a Zenith Alpha Thoracic Stent-Graft for False Lumen Distal Occlusion in Acute-on-Chronic Type B Aortic Dissection.

Purpose: To report a candy-plug technique using a Zenith Alpha stent-graft to occlude the distal false lumen in a patient with a complicated chronic type B aortic dissection. Case Report: A 50-year-old male smoker presented with chest pain due to rapidly growing complicated chronic type B aortic dissection. Computed tomography angiography (CTA) showed the dissection extending from distal to the origin of the left subclavian artery (LSA) down to the left femoral artery. There was fusiform aneurysmal dilatation of the proximal descending aorta measuring up to 5.8 cm in diameter. He underwent left carotid-subclavian artery bypass, thoracic endovascular aortic repair with a Zenith Alpha stent-graft, a left common carotid artery chimney, and embolization of the proximal LSA. Serial CTA showed persistent false lumen flow. A decision was made to occlude the distal large false lumen using the candy-plug technique. A 44×125-mm Zenith Alpha stent-graft was used to prepare the candy plug. A gutter leak and a type Ia endoleak were embolized via a left brachial artery approach. At 2.5 years, imaging showed the candy plug in position, no endoleak, and the thrombosed false lumen in the thoracic aorta reduced in size. Conclusion: The candy-plug technique is useful in facilitating complete occlusion of the false lumen in chronic aortic dissection, which avoids an open procedure and the risk of higher morbidity.

In Vitro Evaluation of Balloon-Expandable Chimney Grafts in the Renal Arteries Combined With the Endurant Endograft.

Purpose: To compare balloon-expandable covered stents (BECS) available for use as renal chimney grafts to the Advanta V12 approved for use with the Endurant endograft. Materials and Methods: A silicone model was manufactured based on preoperative computed tomography angiography (CTA) scans of a patient with a 7-cm juxtarenal aneurysm treated with an Endurant bifurcated endograft and an Advanta V12 covered stent for the 6-mm-diameter right renal artery. The model was placed in a flow box filled with a 37°C blood-mimicking solution equipped with a pulsatile pumping system (140/60 mm Hg). The tested BECS were the Advanta V12, the VBX, and the BeGraft+. A 36-mm-diameter Endurant II endograft with a 16-mm-diameter contralateral limb and a 6×59-mm BECS chimney graft were used in 9 consecutive tests (3 for each combination). After each implantation, the model was placed in the CT scanner, and 2 radiologists blinded to the test device independently measured the gutter areas and the patent chimney graft lumen at the level of the Endurant's suprarenal stent, at the level of the chimney's maximum curvature, and 10 mm inside the renal artery. The intraclass correlation coefficients (ICC) were calculated to assess interreader reliability. Results: The mean gutter areas were 19.3±7, 20.2±8, and 22.3±8 mm2 for the Advanta, VBX, and BeGraft+, respectively (all p>0.05). At the level of the aortic endograft's suprarenal stent struts, the mean diameter of the Advanta V12, VBX, and BeGraft+ were 4.46±0.3, 4.12±0.4, and 4.12±0.3 mm, respectively (all p>0.05). At the level of the maximum chimney graft angulation, the mean diameters were 3.77±0.3, 4.16±0.1, and 3.74±0.3 mm, respectively (all p>0.05). In the right renal artery, the mean diameters were 3.91±0.2, 4.05±0.9, and 4.3±0.4 mm, respectively (all p>0.05). The ICCs varied between 0.7 and 0.9, indicating good agreement between readers. Conclusion: These in vitro findings showed comparable results between the Advanta V12 and the available BECS used in conjunction with the Endurant endograft according to the instructions for use. Further clinical evaluation is needed to confirm these results.

Secondary Fill Minimizes Gutter Size in Chimney EVAS Configurations In Vitro.

PURPOSE: To investigate in an in vitro model if secondary endobag filling can reduce gutter size during chimney endovascular aneurysm sealing (chEVAS). MATERIALS AND METHODS: Nellix EVAS systems were deployed in 2 silicone juxtarenal aneurysm models with suprarenal aortic diameters of 19 and 24 mm. Four configurations were tested: EVAS with 6-mm balloon-expandable (BE) or self-expanding (SE) chimney grafts (CGs) in the renal branches of both models. Balloons were inflated simultaneously in the CGs and main endografts during primary and secondary endobag filling and polymer curing. Computed tomography (CT) was performed immediately after the primary and secondary fills. Cross-sectional lumen areas were measured on the CT images to calculate gutter volumes and percent change. CG compression was calculated as the reduction in lumen surface area measured perpendicular to the central lumen line. The largest gutter volume and highest compression were presented per CG configuration per model. RESULTS: Secondary endobag filling reduced the largest gutter volumes from 99.4 to 73.1 mm3 (13.2% change) and 84.2 to 72.0 mm3 (27.6% change) in the BECG configurations and from 67.2 to 44.0 mm3 (34.5% change) and 92.7 to 82.3 mm3 (11.2% change) in the SECG configurations in the 19- and 24-mm models, respectively. Secondary endobag filling increased CG compression in 6 of 8 configurations. BECG compression changed by -0.2% and 5.4% and by -1.0% and 0.4% in the 19- and 24-mm models, respectively. SECG compression changed by 10.2% and 16.0% and by 7.2% and 7.3% in the 19- and 24-mm models, respectively. CONCLUSION: Secondary endobag filling reduced paragraft gutters; however, this technique did not obliterate them. Increased CG compression and prolonged renal ischemia time should be considered if secondary endobag filling is used.

Deployment of stent graft in an excessively higher position above the renal artery induces a flow channel to the aneurysm in chimney endovascular aortic aneurysm repair: an in vitro study.

We aimed to investigate the influences of the sealing length above the renal artery (RA) on gutter formation, non-apposed regions between the aortic wall, stent graft (SG), and chimney graft and incidence of flow channel to the aneurysm in chimney endovascular aortic aneurysm repair (Ch-EVAR) using a juxtarenal abdominal aortic aneurysm model. Neck diameter and length of the silicone model were 24 and 4 mm, respectively. In double Ch-EVAR configuration using Advanta V12, 12 combinations were tested three times with two sizes [28.5 (20%-oversize) and 31 (30%-oversize) mm] of Excluder SG, three sealing lengths above the RA (10, 20, and 30 mm), and two deployment positions (anatomical and cross-leg). Gutter area, non-apposed region, and flow channels to the aneurysm were analyzed using micro-computed tomography. Average gutter area and non-apposed region of 30%-oversize SG were significantly smaller than those of 20%-oversize SG (p = 0.05). Furthermore, the non-apposed region of 30%-oversize SG with a 30-mm sealing length was significantly larger than that of the other sealing lengths. For 20%-oversize SGs, flow channel to the aneurysm was observed, except for the anatomical deployment with the sealing length of 10 mm. For 30%-oversize SGs, flow channel was absent, except for the SG with a 30-mm sealing length in both deployment positions. These flow channels were frequently formed through a valley space, existing in the lower unibody above the two limbs. Our data indicated that the optimal sealing length should be chosen in consideration of the device design difference due to the device diameter in Ch-EVAR.

Comparison of functional metacarpal splint and ulnar gutter splint in the treatment of fifth metacarpal neck fractures: a prospective comparative study.

BACKGROUND: Fifth metacarpal fractures are the most common fractures of the hand. These fractures are generally treated with conservative methods. The aim of this study was to compare the radiological and clinical outcomes of two conservative treatment methods, functional metacarpal splint(FMS) and ulnar gutter splint(UGS), for the treatment of fifth metacarpal neck fractures. METHODS: A prospective comparative study was designed to assess the conservative treatment of isolated and closed stable fractures of the fifth metacarpal neck. In total, 58 patients were included in the study and were treated with FMS or UGS after fracture reduction in a consecutive order. Angulation, shortening and functional outcome (QuickDASH scores and grip strengths) were evaluated at the 2nd and 6th months. RESULTS: Forty patients returned for follow-up. Twenty-two patients were treated with FMS, and 18 patients were treated with UGS. The average age was 28 years (SD ± 12, range;18-43) in the FMS group and 30 years (SD ± 14, range;18-58) in the UGS group. After reduction, significant correction was achieved in both groups, but the average angulation was lower in the FMS group(16 ± 7) compared with the UGS group (21 ± 8)(p = 0.043). However, this better initial reduction in FMS group(16 ± 7) could not be maintained in the 1st month follow-up (21 ± 5) (p = 0.009). In the FMS group, the improvement in QuickDASH scores between the 2nd and 6th month follow-up was significant (p = 0.003) but not in the UGS group(p = 0.075). When the expected grip strengths were calculated, the FMS group reached the expected strength values at the 2nd month follow-up, whereas the UGS group still exhibited significantly lower grip strength at the 2nd month follow-up(p = 0.008). However, at the end of the 6th month follow-up, both groups exhibited similar reduction, QuickDASH and grip strength values. CONCLUSIONS: In stable 5th metacarpal neck fractures, FMS is adequate to prevent loss of reduction and yields faster improvement in clinical scores with earlier gain of normal grip strength compared with UGS. However, in the long term, both FMS and UGS methods yield similar radiological and clinical outcomes. Patient comfort and compliance may be better with FMS due to less joint restriction, and these findings should be considered when deciding the treatment method. TRIAL REGISTRATION: ISRCTN79534571 The date of registration: 01/04/2019 Type of study/level of evidence: Therapeutic, II.

Screw fixation of the syndesmosis alters joint contact characteristics in an axially loaded cadaveric model.

BACKGROUND: The purpose of this study was to quantify the effects of rigid syndesmotic fixation on functional talar position and cartilage contact mechanics. METHODS: Twelve below-knee cadaveric specimens with an intact distal syndesmosis were mechanically loaded in four flexion positions (20° plantar flexion, 10° plantar flexion, neutral, 10° dorsiflexion) with zero, one, or two 3.5-mm syndesmotic screws. Rigid clusters of reflective markers were used to track bony movement and ankle-specific pressure sensors were used to measure talar dome and medial/lateral gutter contact mechanics. RESULTS: Screw fixation caused negligible anterior and inferior shifts of the talus within the mortise. Relative to no fixation, mean peak contact pressure decreased by 6%-32% on the talar dome and increased 2.4- to 6.6-fold in the medial and lateral gutters, respectively, depending on ankle position and number of screws. CONCLUSIONS: Two-way ANOVA indicated syndesmotic screw fixation significantly increased contact pressure in the medial/lateral gutters and decreased talar dome contact pressure while minimally altering talar position.

In Vitro Quantification of Gutter Formation and Chimney Graft Compression in Chimney EVAR Stent-Graft Configurations Using Electrocardiography-Gated Computed Tomography.

PURPOSE: To assess the dynamic behavior of chimney grafts during the cardiac cycle. METHODS: Three chimney endovascular aneurysm repair (EVAR) stent-graft configurations (Endurant and Advanta V12, Endurant and Viabahn, and Endurant and BeGraft) were placed in silicone aneurysm models and subjected to physiologic flow. Electrocardiography (ECG)-gated contrast-enhanced computed tomography was used to visualize geometric changes during the cardiac cycle. Endograft and chimney graft surface, gutter volume, chimney graft angulation over the center lumen line, and the D-ratio (the ratio between the lengths of the major and minor axes) were independently assessed by 2 observers at 10 time points in the cardiac cycle. RESULTS: Both gutter volumes and chimney graft geometry changed significantly during the cardiac cycle in all 3 configurations (p<0.001). Gutters and endoleaks were observed in all configurations. The largest gutter volume (232.8 mm3) and change in volume (20.7 mm3) between systole and diastole were observed in the Endurant-Advanta configuration. These values were 2.7- and 3.0-fold higher, respectively, compared to the Endurant-Viabahn configuration and 1.7- and 1.6-fold higher as observed in the Endurant-BeGraft configuration. The Endurant-Viabahn configuration had the highest D-ratio (right, 1.26-1.35; left, 1.33-1.48), while the Endurant-BeGraft configuration had the lowest (right, 1.11-1.17; left, 1.08-1.15). Assessment of the interobserver variability showed a high correlation (intraclass correlation >0.935) between measurements. CONCLUSION: Gutter volumes and stent compression are dynamic phenomena that reshape during the cardiac cycle. Compelling differences were observed during the cardiac cycle in all configurations, with the self-expanding (Endurant-Viabahn) chimney EVAR configurations having smaller gutters and less variation in gutter volume during the cardiac cycle yet more stent compression without affecting the chimney graft surface.

Transarterial Endoleak Closure After Endovascular Thoracoabdominal Aneurysm Repair: When the "Sandwich" Goes Wrong.

PURPOSE: To describe the use of vascular plugs to close a complex type Ib endoleak following the sandwich procedure used in conjunction with endovascular thoracoabdominal aortic aneurysm (TAAA) repair. CASE REPORT: A 59-year-old man with a 6.5-mm TAAA was treated with initial deployment proximally of 2 Zenith TX2 stent-grafts. In preparation for the sandwich technique to preserve flow to the celiac trunk, a 10×100-mm Viabahn covered stent was delivered from a brachial access into the celiac trunk unprotected by the sheath of the introducer. The trigger wire system became snagged on the struts of the distal aortic stent-graft; when the wire was pulled, the proximal end of the Viabahn migrated outside the aortic stent-graft, which migrated upward. The main body extension intended for the aortic component of the sandwich technique was deployed close to the distal end of the aneurysm sac, but a large type Ib endoleak formed in the gutter between the Viabahn, aortic extension, and sac wall. The leak perfused the celiac trunk, and the procedure was terminated. Increasing sac size on 3-month imaging prompted closure of the leak with 2 type II Amplatzer vascular plugs aiming to occlude the endoleak outflow into the Viabahn and the endoleak outflow at the site of the gutter. Imaging follow-up at 6 months demonstrated successful exclusion of the TAAA with no residual endoleak and excellent perfusion of the celiac trunk. CONCLUSION: Transarterial treatment of complex endoleaks is feasible when preceded by meticulous imaging and detailed preprocedural planning.

EndoAnchors to Resolve Persistent Type Ia Endoleak Secondary to Proximal Cuff With Parallel Graft Placement.

PURPOSE: To describe 2 patients with a distally migrated endograft causing a type Ia endoleak and treatment with a proximal cuff and chimney grafts that required EndoAnchors to finally seal the leak. CASE REPORT: Two men, ages 86 and 72 years, presented with stent-graft migration and type Ia endoleak at 5 and 15 years after endovascular repair, respectively. Both were treated with a proximal cuff in combination with a chimney graft to the left renal artery. In both cases, the type Ia endoleak persisted, likely due to gutter formation. Both patients were treated in the same setting with EndoAnchors that instantly resolved the endoleak. At 1-year follow-up, there was no recurrent endoleak or migration, with patent chimney grafts and renal arteries and stable renal function. CONCLUSION: EndoAnchors may effectively resolve a persistent type Ia endoleak arising from gutter formation after placement of a proximal cuff and chimney grafts.

Aetiology, incidence and morphology of the C-shaped root canal system and its impact on clinical endodontics.

The C-shaped root canal constitutes an unusual root morphology that can be found primarily in mandibular second permanent molars. Due to the complexity of their structure, C-shaped root canal systems may complicate endodontic interventions. A thorough understanding of root canal morphology is therefore imperative for proper diagnosis and successful treatment. This review aims to summarize current knowledge regarding C-shaped roots and root canals, from basic morphology to advanced endodontic procedures. To this end, a systematic search was conducted using the MEDLINE, BIOSIS, Cochrane Library, EMBASE, Google Scholar, Web of Science, PLoS and BioMed Central databases, and many rarely cited articles were included. Furthermore, four interactive 3D models of extracted teeth are introduced that will allow for a better understanding of the complex C-shaped root canal morphology. In addition, the present publication includes an embedded best-practice video showing an exemplary root canal procedure on a tooth with a pronounced C-shaped root canal. The survey of this unusual structure concludes with a number of suggestions concerning future research efforts.