scholarly journals Evaluation of the Stability of Intracranial Aneurysms Occluded with Guglielmi Detachable Coils

2001 ◽  
Vol 7 (1_suppl) ◽  
pp. 143-148 ◽  
Author(s):  
S. Tamatani ◽  
Y. Ito ◽  
T. Koike ◽  
H. Abe ◽  
T. Kumagai ◽  
...  
Keyword(s):  
Guglielmi Detachable Coils ◽  
Aneurysm Neck ◽  
Term Stability ◽  
Long Term Stability ◽  
Detachable Coils ◽  
The Mean ◽  
The Stability ◽  
Small Aneurysms

The purpose of this study is to evaluate the long-term stability of embolized aneurysms using the volume embolization rate (VER). One hundred and six aneurysms in 96 patients who were treated with Guglielmi detachable coils were selected for this study. Follow-up angiography was performed at six or more months after initial treatment. Every aneurysm was packed as densely as possible, however, the percentage of stability varied according to the size of the aneurysm or the size of the aneurysm neck. The percentage of stable aneurysm was 82% (56/68) in small aneurysms with small necks, 68% (13/19) in small aneurysms with wide necks and 42% (8/19) in large aneurysms. The mean VER of embolized aneurysms in each size was 30%, 22% and 17%, respectively. There was a correlation between the percentage of stable aneurysms and the mean VER. On the other hand, there seemed to be a difference of VER for the stability of embolized aneurysms between ruptured aneurysms and unruptured ones. In small aneurysms with small necks, the stability of embolized aneurysms in ruptured ones was obtained only when the VER was greater than 30%, whereas it was found in unruptured ones even though the VER was less than 20%. In conclusion, the long-term stability of embolized aneurysms was obtained in small-sized aneurysms, especially small neck aneurysms, and unruptured ones. The VER is a good, objective index to predict the long-term stability of embolized aneurysms.

scholarly journals Evaluation of the Stability of Small Ruptured Aneurysms with a Small Neck after Embolization with Guglielmi Detachable Coils

2006 ◽  
Vol 12 (1_suppl) ◽  
pp. 91-96 ◽  
Author(s):  
Y. Kai ◽  
J. Hamada ◽  
M. Morioka ◽  
S. Yano ◽  
J. Kuratsu
Keyword(s):  
Endovascular Surgery ◽  
Guglielmi Detachable Coils ◽  
Ruptured Aneurysms ◽  
Detachable Coils ◽  
The Mean ◽  
The Difference ◽  
The Stability ◽  
The Relationship ◽  
Ruptured Intracranial Aneurysms

It is difficult to predict the compaction of Guglielmi detachable coils (GDC) after endovascular surgery for aneurysms. Therefore, we studied the relationship between the coil packing ratio and compaction in 62 patients with acute ruptured intracranial aneurysms that were small (<10 mm) had a small neck (<4 mm) and were coil-embolized with GDC-10. We recorded the maximum prospective coil length, L, as the length that correspond with the volume of packed coils occupying 30% of the aneurysmal volume. L was calculated as L (cm) = 0.3 × a × b × c and the coil packing ratio expressed as packed coil length/L × 100, where a, b, and c are the aneurysmal height, length, and width in mm, respectively. Angiographic follow-up studies were performed at three months and one and two years after endovascular surgery. Of the 62 patients, 16 (25.8%) manifested angiographic coil compaction (ten minor and six major compactions); the mean coil packing ratio was 51.9 ± 13.4%. The mean coil packing ratio in the other 46 patients was 80.5 ± 20.2% and the difference was statistically significant (p<0.01). In all six patients with major compaction the mean packing ratio was below 50%. We detected 93.8% of the compactions within 24 months of coil placement. In patients with small, necked aneurysms, the optimal coil packing ratio could be identified with the formula 0.3 × a × b × c. The probability of compaction was significantly higher when the coil packing ratio was under 50%. To detect coil compaction post-embolization, follow-up angiograms must be examined regularly for at least 24 months.

scholarly journals The Long-Term Stability of Fat-Graft Myringoplasty in the Closure of Tympanic Membrane Perforations and Hearing Restoration

ORL ◽  
2020 ◽  
pp. 1-8
Author(s):  
Jae Sang Han ◽  
Jung Ju Han ◽  
Jung Mee Park ◽  
Jae-Hyun Seo ◽  
Kyoung Ho Park
Keyword(s):  
Tympanic Membrane ◽  
Fat Graft ◽  
Closure Rate ◽  
Tertiary Referral Center ◽  
Term Stability ◽  
Long Term Stability ◽  
Tympanic Membrane Perforations ◽  
The Mean

<b><i>Background/Aims:</i></b> This study was conducted to evaluate the long-term stability of fat-graft myringoplasty (FGM) for chronic tympanic membrane perforations, analyzing the perforation closure rate and re-gained hearing outcome with respect to the size and location of the perforations. <b><i>Methods:</i></b> Between August 2007 and June 2018, a total of 193 patients who underwent FGM due to chronic tympanic membrane perforation at a tertiary referral center were enrolled and analyzed. <b><i>Results:</i></b> The mean follow-up was 14.6 months (range 6–39). The complete perforation closure rate after FGM was 89.6%, with no statistical difference among the perforation size groups. The mean postoperative air-bone gap (ABG) was 11.0 dB and mean ABG improvement was 4.9 dB. <b><i>Conclusion:</i></b> Our FGM technique had a favorable tympanic closure rate for small to large perforations, and yielded relatively good hearing improvement in the mid-size perforation cases over long-term follow-up periods. According to the topographic evaluation of FGM, this procedure resulted in a reliable perforation closure rate and audiological results regardless of the perforation site.

Evaluation of the Stability of Small Ruptured Aneurysms with a Small Neck after Embolization with Guglielmi Detachable Coils: Correlation between Coil Packing Ratio and Coil Compaction

Neurosurgery ◽  
2005 ◽  
Vol 56 (4) ◽  
pp. 785-792 ◽  
Author(s):  
Yutaka Kai ◽  
Jun-ichiro Hamada ◽  
Motohiro Morioka ◽  
Shigetoshi Yano ◽  
Jun-ichi Kuratsu
Keyword(s):  
Side Wall ◽  
Endovascular Surgery ◽  
Guglielmi Detachable Coils ◽  
Simple Method ◽  
Coil Diameter ◽  
Detachable Coils ◽  
The Mean ◽  
The Difference ◽  
The Stability

Abstract OBJECTIVE: Because it is difficult to predict the compaction of Guglielmi detachable coils (GDCs) after endovascular surgery for aneurysms, we studied the relationship between the coil packing ratio and compaction. Here, we propose a simple method for the preoperative estimation of coil compaction. Using follow-up angiograms, we studied the timing and degree of coil compaction in small terminal and side-wall aneurysms with narrow necks. METHODS: We studied 62 patients with acute ruptured intracranial aneurysms that were small (&lt;10 mm), had a small neck (&lt;4 mm), and were coil embolized with GDC-10s. The aneurysmal volume was calculated using the equation V = 4/3π(a/2) × (b/2) × (c/2), where a, b, and c are the aneurysmal height, length, and width in millimeters, respectively. The coil volume was calculated using the equation V = π(p/2)2 × l × 10, where p represents the GDC-10 coil diameter (0.25 mm) and l is the coil length. We recorded the maximum prospective coil length, L, as that corresponding with the volume of packed coils occupying 30% of the aneurysmal volume. Therefore, L was calculated as L (cm) = 0.3 × a × b × c, and the coil packing ratio was expressed as packed coil length/L × 100. Angiographic follow-up studies were generally performed at 3 months and 1 and 2 years after endovascular surgery. We considered coil compaction exceeding 2 mm as major compaction and recorded minor compaction when it was less than 2 mm of the empty reappeared space in the embolized aneurysm. Aneurysmal location was recorded as terminal or side wall. RESULTS: Of the 62 patients, 16 (25.8%) manifested angiographic coil compaction (10 minor and 6 major compactions); the mean coil packing ratio was 51.9 ± 13.4%. The mean coil packing ratio in the other 46 patients was 80.5 ± 20.2%, and the difference was statistically significant (P &lt; 0.01). In all 6 patients with major compaction, the mean packing ratio was less than 50% and all underwent re-embolization after a mean of 24.9 ± 1.1 months. The 10 patients with minor compaction were conservatively treated, and the degree of compaction did not change during a mean period of 24 months. We detected 93.8% of the compactions within 12 months of coil placement. The aneurysm was of the terminal type in 5 of the 6 patients with major coil compaction. CONCLUSION: In patients who underwent embolization with GDC-10s of aneurysms that were small and had a small neck, the optimal coil packing ratio could be identified with the formula 0.3 × a × b × c. The probability of coil compaction was significantly higher when the coil packing ratio was less than 50%. To detect coil compaction after embolization, follow-up angiograms must be examined regularly for at least 12 months. To detect major coil compaction in patients with terminal type aneurysms, angiographic follow-up should not be shorter than 24 months.

Long-term stability of Onyx: is there any indication for repeated angiography after dural arteriovenous fistula embolization?

2021 ◽  
pp. 1-10
Author(s):  
Richard Voldřich ◽  
David Netuka ◽  
František Charvát ◽  
Vladimír Beneš
Keyword(s):  
Transarterial Embolization ◽  
Diagnostic Methods ◽  
Term Stability ◽  
Long Term Stability ◽  
Prospective Group ◽  
Significant Difference ◽  
Long Term Follow Up ◽  
The Mean

OBJECTIVE The natural course of dural arteriovenous fistulas (DAVFs) is unfavorable. Transarterial embolization with Onyx is currently the therapeutic method of choice, although the long-term stability of Onyx has been questioned. The literature reports a significant difference in the recurrence rate after complete DAVF occlusion and lacks larger series with long-term follow-up. The authors present the largest series to date with a long-term follow-up to determine the stability of Onyx, prospectively comparing magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) as follow-up diagnostic methods. METHODS Demographics, clinical symptomatology, length of follow-up, diagnostic methods, and angiographic findings of DAVFs were recorded and retrospectively evaluated in 112 patients. A prospective group of 15 patients with more than 5 years of follow-up after complete DAVF occlusion was established. All 15 patients in the prospective group underwent a clinical examination and MRA; 10 of these patients also underwent DSA. The recurrences and the correlation between the two diagnostic methods were evaluated. RESULTS Among the 112 patients, 71 were men and 41 were women, with an average age of 60 years. Intracranial hemorrhage (40%) was the most common clinical presentation of DAVF. At the last follow-up, 73% of the patients experienced clinical improvement, 21% remained unchanged, and 6% worsened. Overall, 87.5% of the DAVFs were occluded entirely with endovascular treatment, and 93% of the DAVFs were classified as cured at the last follow-up (i.e., completely embolized DAVFs and DAVFs that thrombosed spontaneously or after Gamma Knife surgery). Two recurrences of DAVFs were recorded in the entire series. Both were first diagnosed by MRA and confirmed with DSA. The mean follow-up was 27.7 months. In the prospective group, a small asymptomatic recurrence was diagnosed. The mean follow-up of the prospective group was 96 months. CONCLUSIONS Onyx is a stable embolic material, although recurrence of seemingly completely occluded DAVFs may develop because of postembolization hemodynamic changes that accentuate primarily graphically absent residual fistula. These residuals can be diagnosed with MRA at follow-up. The authors’ data suggest that MRA could be sufficient as the follow-up diagnostic method after complete DAVF occlusion with Onyx. However, larger prospective studies on this topic are needed.

Follow-up Angiography of Intracranial Aneurysms Treated with Endovascular Placement of Guglielmi Detachable Coils

Neurosurgery ◽  
2002 ◽  
Vol 50 (2) ◽  
pp. 239-250 ◽  
Author(s):  
John Thornton ◽  
Gerard M. Debrun ◽  
Victor A. Aletich ◽  
Qasim Bashir ◽  
Fady T. Charbel ◽  
...  
Keyword(s):  
Intracranial Aneurysms ◽  
Endovascular Coiling ◽  
Guglielmi Detachable Coils ◽  
Detachable Coils ◽  
Aneurysm Occlusion ◽  
Male Patients ◽  
The Mean ◽  
Angiographic Findings

ABSTRACT OBJECTIVE The success of endovascular treatment of intracranial aneurysms with Guglielmi detachable coils (GDCs) is dependent on the long-term exclusion of the aneurysm from the circulation. We reviewed our experience with the long-term angiographic follow-up monitoring of aneurysms that had been treated with GDCs. METHODS All patients whose aneurysms had been treated with GDCs between January 1995 and August 1999 and who subsequently underwent follow-up angiography at 6 months or more were included in this study. We reviewed all of the angiographic findings, to determine the percentage of aneurysm occlusion on the initial angiograms and on the last available follow-up angiograms. The categories of aneurysm occlusion used were 100%, ≥95%, and less than 95% occlusion. RESULTS One hundred thirty patients with 141 aneurysms underwent 143 endovascular coiling procedures and subsequently underwent angiographic follow-up monitoring of 6 months or more. There were 102 female and 28 male patients. The mean angiographic follow-up period was 16.7 months (range, 6–62 mo). The initial rates of occlusion were 100% for 56 aneurysms (39%), ≥95% for 65 aneurysms (46%), and less than 95% for 22 aneurysms (15%). Recurrence of one aneurysm (1.8%) was observed. Of the 87 aneurysms that were incompletely occluded initially, there was progressive thrombosis in 40 (46%), stable neck remnants in 23 (26%), and enlargement of the residual neck in 24 (28%). The final occlusion rates, determined on the last available angiograms, were 100% for 88 aneurysms (61%), ≥95% for 31 aneurysms (22%), and less than 95% for 24 aneurysms (17%). No patient experienced repeat or new subarachnoid hemorrhage more than 6 months after the initial treatment. CONCLUSION Late angiographic follow-up monitoring of aneurysms that have been treated with GDCs demonstrates the durability of the treatment. Aneurysms with large residual neck remnants were subjected to further treatment, whereas aneurysms with small residual neck remnants remain under observation.

LONG-TERM STABILITY ANALYSIS OF ACOUSTIC ABSORBING BOUNDARY CONDITIONS

2013 ◽  
Vol 23 (11) ◽  
pp. 2129-2154 ◽  
Author(s):  
HÉLÈNE BARUCQ ◽  
JULIEN DIAZ ◽  
VÉRONIQUE DUPRAT
Keyword(s):  
Stability Analysis ◽  
Boundary Conditions ◽  
Absorbing Boundary Conditions ◽  
Computational Domain ◽  
Acoustic Wave Equation ◽  
Absorbing Boundary ◽  
Term Stability ◽  
Long Term Stability ◽  
The Stability

This work deals with the stability analysis of a one-parameter family of Absorbing Boundary Conditions (ABC) that have been derived for the acoustic wave equation. We tackle the problem of long-term stability of the wave field both at the continuous and the numerical levels. We first define a function of energy and show that it is decreasing in time. Its discrete form is also decreasing under a Courant–Friedrichs–Lewy (CFL) condition that does not depend on the ABC. Moreover, the decay rate of the continuous energy can be determined: it is exponential if the computational domain is star-shaped and this property can be illustrated numerically.

Class II treatment in early mixed dentition with the eruption guidance appliance: effects and long-term stability

2019 ◽  
Vol 42 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Katri Keski-Nisula ◽  
Leo Keski-Nisula ◽  
Juha Varrela
Keyword(s):  
Treatment Group ◽  
Class Ii ◽  
Post Treatment ◽  
Mixed Dentition ◽  
Term Stability ◽  
Long Term Stability ◽  
Class Ii Treatment ◽  
Significant Correction ◽  
The Mean

Summary Objectives Our aim was to analyse dentoskeletal effects and long-term stability of Class II treatment carried out with an eruption guidance appliance (EGA) in early mixed dentition. Materials and methods Sixty-five Class II patients (38 females and 27 males), treated with an EGA in early mixed dentition, were compared with 58 children (26 females and 32 males) with untreated Class II malocclusion. The mean age in the treatment group at the start (T1) and end of treatment (T2) was 5.4 years (±0.4) and 8.5 years (±0.9), respectively, and at the final examination in the early permanent dentition (T3) 16.7 years (±0.4). In the control group, the mean age at T1 and T2 were 5.1 years (±0.5) and 8.4 years (±0.5), respectively. The independent and dependent sample t-tests, Chi-square test, and Fisher’s test were used in the statistical evaluation. Results In the treatment group, the frequency of Class II decreased from 100 to 14% during the treatment (T1–T2) and a significant correction took place in all occlusal variables. At T2, the treatment and control groups showed statistically significant differences (P &lt; 0.05) in all occlusal variables. In the treated children, mandibular length increased 5 mm more (P &lt; 0.001) from T1 to T2 compared to the control children, and the ANB angle became significantly smaller (P = 0.006). During the post-treatment period (T2–T3), the frequency of Class II in the treatment group decreased from 14 to 2% (P &lt; 0.05), overbite increased from 2.2 to 3.1 mm (P &lt; 0.05), and lower crowding increased from 2to 14% (P &lt; 0.05). Post-treatment changes in overjet and upper crowding were not statistically significant. At T3, the mean values of the SNA, SNB, and ANB angles were 83.0° (SD 3.9°), 81.3° (SD 3.8°), and 2.4° (SD 1.5°), respectively. Conclusions A clinically significant correction of the molar relationship, overjet, overbite, incisor alignment, and growth enhancement of the mandible were observed after treatment in early mixed dentition. The treatment results remained largely stable in the early permanent dentition. However, an increase was observed in overbite and lower crowding. None of the children treated in early mixed dentition needed a second treatment phase.

Fabrication of Boron Compensated Hydrogenated Amorphous Silicon Films with Significantly Improved Stability Using Plasma Enhanced Chemical Vapor Deposition Technique

1995 ◽  
Vol 377 ◽  
Author(s):  
Mohan K. Bhan
Keyword(s):  
Chemical Vapor ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Vapor Deposition Technique ◽  
Improved Stability ◽  
Donor Acceptor ◽  
B Doping ◽  
The Stability

ABSTRACTWe have systematically investigated the effects of addition of sub-ppm levels of boron on the stability of a-Si:H films and p-i-n devices, deposited by PE-CVD technique. The films thus produced with appropriate amounts of boron, show a significant improvement in stability, when soaked under both AM 1.5 (short-term) as well as 10×sun (long-term) illumination conditions. The opto-electronic properties of the films are quite respectable It is concluded that boron compensates the native impurities by forming donor-acceptor pairs, which reduces the “fast” defects and hence the initial degradation of the films. It is also speculated that boron may also be improving the short-term stability, by reducing the recombination of light generated electrons and holes, by converting D° into D+ states. The long-term stability appears to get affected by hydrogen dilution which seems to reduce the amount of “slow” defects. As a result of B doping of i-layer, the initial conversion efficiency of the devices decreases. It is presumed that our devices may contain an enhanced level of boron impurity, than expected, making them as worse material and to degrade less.

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