Coil Group Research Articles

Cost Analysis of Endovascular Coiling and Surgical Clipping for the Treatment of Ruptured Intracranial Aneurysms

Cost-effectiveness analyses for the treatment of aneurysmal subarachnoid hemorrhage are necessary to determine health policy, treatment guidelines, and screening protocols for cerebral aneurysms. To perform these modeling studies, detailed cost data are necessary and are currently lacking. The goal of this study was to determine detailed inpatient cost of aneurysmal subarachnoid hemorrhage. A retrospective review of our ruptured subarachnoid hemorrhage database was performed to identify consecutive patients between January 2013 and December 2015. Patients were searched by International Classification of Disease 9 diagnosis and procedure codes. Patient demographics and clinical characteristics were acquired. The cost breakdown was compiled into a comprehensive itemized list encompassing all aspects of hospitalization. A mean cost based on resource used per patient was obtained. There were 269 patients treated, 209 were coiled and 60 were clipped. Mean age in the clipping group was 49 years and 55 years in the coil group (P= 0.006). Other patient demographics and clinical characteristics were found to be statistically similar for both groups. Total cost per patient for treatment and hospital stay was $74,192 for clipping and $85,553 for coiling (P= 0.06). Cost amplified with increasing Hunt and Hess grade in both clipping and coiling groups. The detailed cost information reported in this article can be used to help establish appropriate, standardized costs nationally by improving transparency. It can also help provide critical information necessary to develop cost-effective treatment algorithms and screening protocols.

Simulation and Analysis of Irregular Multicoil B0 Shimming in C-type Permanent Magnets Using Genetic Algorithm and Simulated Annealing

Multicoil (MC) B0 shimming, a new shimming technology developed in the recent years, exhibits unique advantages. Irregularly shaped coils can further improve the shimming effect of the MC, but they increase the difficulty and complexity of MC design. In this paper, the shimming characteristics of MC in C-type permanent magnets are studied. Aiming at improving the efficiency of finding the optimal shape for irregular MC, this paper presents a method that uses genetic algorithm and simulated annealing (GASA) to optimize irregular MC shapes for shimming. By simulating the shimming of the irregular MC of the flat-plate model and shoulder-joint model in C-type permanent magnets, the effects of parameters such as complexity, size, and number of groups of coils are analyzed. The shimming of MC in superconducting magnets and permanent magnets is compared and the optimization efficiencies of the genetic algorithms and genetic–annealing algorithms are compared. The results show that an irregular MC can achieve a better shimming effect for a locally nonuniform B0 field in a sample boundary region of a C-type permanent magnet. GASA is found to be a more stable and highly efficient optimization method.

Synthesis Strategy for Stator Magnetic Field of Permanent Magnet Spherical Motor

Considering the basic role of the stator magnetic field (MF), this paper presents a synthesis strategy for stator MF of a permanent magnet spherical motor (PMSM). Given the structure of the PMSM, the MF of a stator coil group with unit current is obtained, and the spherical harmonic components are decomposed, so the relationship between the whole stator MF and coils currents can be deduced by the rotary transformation and superposition. Referring to the rotor MF, the expected stator MF is determined; then, the stator coil currents are calculated by solving a constrained optimization. Finally, the current excitation strategy of stator coils is verified by finite-element analysis and experiments.

Performance Analysis of Synchronous Machines After Disconnecting Stator Coils

This paper offers methods to analyze the performance of three-phase synchronous machines operating with an unsymmetrical stator winding caused by cutting out and bypassing coils. The resulting unsymmetrical current distribution in the stator winding tends to produce overheating in parts of the stator and damper windings at full load as well as torque pulsations. Thus, the main objective of this study is to determine the maximal load, under which the unsymmetrical machine may operate without exceeding the permissible temperature limit. Based on the multiloop method, a mathematical model of a synchronous machine with missing coils in the stator winding is developed. In order to determine the current distribution, the machines’ system of differential equations is solved by using a numerical integration method (Runge–Kutta method). As an alternative method, the system of differential equations in the steady state is reduced to a system of algebraic equations, which can be solved with the Gaussian elimination method. Both methods are validated by the measurement results of a 25-kW salient pole synchronous machine. Furthermore, both the circulating current within the parallel branches and the line currents of the different phases as a result of coil or coil group cut-outs are analyzed for a large 41-MW cylindrical rotor synchronous motor.

Coreless AFPM Pulsed Alternator With Low Internal Inductance

The linear induction launcher consists of two parts: the barrel section and the projectile section. The barrel contains of a long coaxial sectionalized group of coils that are energized by a capacitor bank or generator sets. This paper deals with the design, implementation, and experimental test of a coreless axial-flux permanent magnet (AFPM) pulsed alternator with a flywheel system as an energy source for linear induction coil launchers. The proposed coreless AFPM generator has a low internal inductance and resistance of stator windings without compensation windings when compared with the conventional iron core machines. This paper describes the coreless AFPM generator configuration and shows the simulation findings.

Loop microcatheter technique for coil embolization of paraclinoid aneurysms.

Although paraclinoid aneurysms do not exhibit a high risk of rupture, coil embolization is not always easy because of unstable microcatheter position. We present a technique that allows a stable microcatheter position for coil embolization of paraclinoid aneurysms. We enrolled 34 consecutive patients who underwent coil embolization for paraclinoid aneurysms. A loop of distal microcatheter was shaped based on three-dimensional rotational angiography. The basic concept is to keep the proximal loop abutting the opposite wall of the aneurysm while using the distal loop for coiling. Then, a proximal curve was made to accommodate the shape of the carotid siphon, which may decide the direction of the loop. Stent-assisted coil embolization was performed in 19 wide-necked aneurysms. Immediate radiological outcomes were analyzed with Raymond classification and clinical outcomes were evaluated with modified Rankin Scale (mRS) scores. Satisfactory occlusion of aneurysm was achieved in 94.1% (32/34) of patients with a Raymond score of 1 or 2. Packing density of ≥ 31% was achieved in 71% (24/34) of patients. No significant differences were observed between stent-assisted coiling and coiling-only groups. Follow-up magnetic resonance angiography and/or angiogram showed stable coil position, except in one patient with tiny recurrence (from Raymond scores 1 to 2) that did not require retreatment at the 6-month follow-up. mRS scores of 0-1 were obtained in all patients at 6months. Loop microcatheter technique allowed safe and stable coil packing for paraclinoid aneurysms. The same procedural concept is also being used for aneurysms in other vascular territories.

Nit-Occlud Lê VSD coil versus Duct Occluders for percutaneous perimembranous ventricular septal defect closure

To evaluate the efficacy and safety of Nit-Occlud Lê VSD Coil versus Duct Occluders for percutaneous closure of perimembranous ventricular septal defect (pmVSD). VSD closure using conventional pmVSD occluders has been largely abandoned because of an unacceptable high rate of complete heart block (CHB). The advantages of Duct Occluders and VSD Coil are supposed to reduce the drawbacks of previous devices, especially CHB complications. Patients underwent percutaneous pmVSD closure were divided into Coil group (using VSD Coil, n = 71) and DO group (using Duct Occluders, n = 315). Patient demographics, clinical presentations, echocardiography measurements, procedure details and follow-up data were collected. The procedure success rate was high in both DO group (95.6%) and Coil group (97.2%, P = .53). The closure rate immediately after procedure in the DO group was higher than that in the Coil group (76.8% vs. 58.0%, P < .01). After 6 months, the closure rate was not significantly different between the 2 groups (DO group 91.3% vs. Coil group 84.1%, P = .07). The mean follow-up time was 61.4 ± 24.1 months. The major complication rate was low in both groups (DO group 1.9% vs. Coil group 1.4%, P = .78). Two patients (0.7%) in the DO group and one patient (1.4%) in the Coil group with CHB needed permanent pacemaker (P = .5). Device embolization (3 patients, 1.0%) and endocarditis (1 patient, 0.3%) occurred only in the DO group. There was no death, disability or other major complications detected in either group. Percutaneous pmVSD closure using either Nit-Occlud Lê VSD Coil or Duct Occluders is feasible, safe and efficacious in selected patients. The main problems of Duct Occluders are unsuitable defect anatomy and device embolization while VSD Coil disadvantages are residual shunt and hemolysis.

Measurement and Analysis of Low Frequency Magnetic Shielding Performance of Open-Cell Nickel Foam

Low frequency magnetic field in the range from 10 to 500 kHz is between very-low and mid-high frequencies, mainly coming from industrial equipments such as antenna, battery, inverter, etc. In some shielding applications simultaneously demanding for ventilation and cooling, high-performance shielding materials with a porous structure are necessary. However, the investigation of these materials in this band was rarely reported. Open-cell nickel foam has excellent electrical conductivity and magnetic permeability, which makes it a potential new kind of shielding material in the field of low frequency magnetic shielding. It is generally believed that, in this band, materials shield the magnetic field mainly through two mechanisms, i.e., flux shunting and eddy current cancellation. With the equation of shielding effectiveness (SE) for a cylindrical shell, SEs of copper foil and Permalloy were calculated. The results indicated that the effect of flux shunting can be ignored, which was further verified by the results of Helmholtz coil test. Thus, only eddy current cancellation mechanism was considered to establish a shielding model, in which the flat open-cell nickel foam was assumed to be a group of coils and the eddy current was assumed to flow along the conductive paths composed of the coils. The prediction of the model was verified by the measured results of a window test method. Both the experimental and theoretical results revealed that, SE is enhanced with the decrease of the average pore size of the foam because the number of conductive paths in the foam increases. In addition, the calculated results of SE indicated that the open-cell nickel foam has no obvious superiority compared to a fully dense nickel strip of the same areal density. However, the structure characteristics of open-cell foam make it definite to find applications simultaneously asking for shielding, ventilating and cooling.

The utility of dual-energy CT for metal artifact reduction from intracranial clipping and coiling

ObjectiveTo assess the ability of dual-energy CT (DECT) to reduce metal-related artifacts in patients with clips and coils in head CT angiography, and to analyze the differences in this reduction between both type of devices. Materials and methodsThirteen patients (6 clips, 7 coils) were selected and retrospectively analyzed. Virtual monoenergetic images (MEI) with photon energies from 40 to 150keV were obtained. Noise was measured at the area of maximum artifact. Subjective evaluation of streak artifact was performed by two radiologists independently. Differences between noise values in all groups were tested by using the ANOVA test. Mann–Whitney U test was used to compare the differences between clips and coils. Cohen's κ statistic was used to determine interobserver agreement. ResultsThe lowest noise value was observed at high energy levels (p<0.05). Noise was higher in the coil group than in the clip group (p<0.001). Interobserver agreement was good (κ=0.72). ConclusionsTCED with MEI helps to minimize the artifact from clips ands coils in patients who undergo head CT angiography. The reduction of the artifact is greater in patients with surgical clipping than in patients with endovascular coiling.

Trans Arterial Embolization of Non-variceal Upper Gastrointestinal Bleeding: Is the Use of Ethylene–Vinyl Alcohol Copolymer as Safe as Coils?

The safety of liquid embolics over the conventional coils for the treatment of non-variceal upper gastrointestinal bleeding (UGIB) approach is still unclear. Purpose of this study is to assess the safety of ethylene-vinyl alcohol copolymer (EVOH 6%) over coils in the treatment of UGIB. All the upper gastrointestinal tract embolization procedures performed in a single center in a 6-year period were reviewed. Patients embolised with coils (Group A) versus those embolised with EVOH 6% (Group B) were compared. Technical/clinical success, bleeding recurrence, complication and mortality rates were analyzed. A total 71 patients were included in the study (41 Group A and 30 Group B). Coagulopathy was present in 21% of Group A and 46% of Group B patients (p < 0.05). Technical and clinical success was 97.6 and 92.7% for Group A, and 100 and 93.3% for Group B respectively, (p > 0.05). Ten patients (17% Group A; 10% Group B) re-bled within the first 36h and all of them were re-treated successfully with a second embolization. In Group A one major complication (bowel ischemia) occurred. No complication occurred in Group B. The survival rate in the first 30days was 90.3% for group A and 90% for group B (p > 0.05). This study demonstrated EVOH 6% appears to be as safe and effective as coils in the treatment of non-variceal UGIB.

Effects of transcranial LED therapy on the cognitive rehabilitation for diffuse axonal injury due to severe acute traumatic brain injury: study protocol for a randomized controlled trial

BackgroundPhotobiomodulation describes the use of red or near-infrared light to stimulate or regenerate tissue. It was discovered that near-infrared wavelengths (800–900 nm) and red (600 nm) light-emitting diodes (LED) are able to penetrate through the scalp and skull and have the potential to improve the subnormal cellular activity of compromised brain tissue. Different experimental and clinical studies were performed to test LED therapy for traumatic brain injury (TBI) with promising results. One of the proposals of this present study is to develop different approaches to maximize the positive effects of this therapy and improve the quality of life of TBI patients.Methods/designThis is a double-blinded, randomized, controlled trial of patients with diffuse axonal injury (DAI) due to a severe TBI in an acute stage (less than 8 h). Thirty two patients will be randomized to active coil helmet and inactive coil (sham) groups in a 1:1 ratio. The protocol includes 18 sessions of transcranial LED stimulation (627 nm, 70 mW/cm2, 10 J/cm2) at four points of the frontal and parietal regions for 30 s each, totaling 120 s, three times per week for 6 weeks, lasting 30 min. Patients will be evaluated with the Glasgow Outcome Scale Extended (GOSE) before stimulation and 1, 3, and 6 months after the first stimulation. The study hypotheses are as follows: (1) transcranial LED therapy (TCLT) will improve the cognitive function of DAI patients and (2) TCLT will promote beneficial hemodynamic changes in cerebral circulation.DiscussionThis study evaluates early and delayed effects of TCLT on the cognitive rehabilitation for DAI following severe acute TBI. There is a paucity of studies regarding the use of this therapy for cognitive improvement in TBI. There are some experimental studies and case series presenting interesting results for TBI cognitive improvement but no clinical trials.Trial registrationClinicalTrials.gov, NCT03281759. Registered on 13 September 2017.

Utilidad de la tomografía computarizada de energía dual en la reducción del artefacto metálico generado por clips y coils intracraneales

ObjectiveTo assess the ability of dual-energy CT (DECT) to reduce metal-related artifacts in patients with clips and coils in head CT angiography, and to analyze the differences in this reduction between both type of devices. Materials and methodsThirteen patients (6 clips, 7 coils) were selected and retrospectively analized. Virtual monoenergetic images (MEI) with photon energies from 40 to 150 keV were obtained. Noise was measured at the area of maximum artifact. Subjective evaluation of streak artifact was performed by two radiologists independently. Differences between noise values in all groups were tested by using the ANOVA test. Mann-Whitney U test was used to compare the differences between clips and coils. Coheńs κ statistic was used to determine interobserver agreement. ResultsThe lowest noise value was observed at high energy levels (p<0,05). Noise was higher in the coil group than in the clip group (p<0.001). Interobserver agreement was good (κ=0.72). ConclusionsTCED with MEI helps to minimize the artifact from clips ands coils in patients who undergo head CT angiography. The reduction of the artifact is greater in patients with surgical clipping than in patients with endovascular coiling.

A General Mathematical Formulation for Winding Layout Arrangement of Electrical Machines

Winding design methods have been a subject of research for many years of the past century. Many methods have been developed, each one characterized by some advantages and drawbacks. Nowadays, the star of slots is the most widespread design tool for electrical machine windings. In this context, this paper presents a simple and effective procedure to determine the distribution of the slot EMFs over the phases and of the winding configuration in all possible typologies of electrical machines equipped with symmetrical windings. The result of this procedure gives a Winding Distribution Table (WDT), which can be used to define coils and coil groups connections and also to simply implement winding optimizations techniques, such as zone widening, imbrication, etc. Moreover, this procedure can be easily implemented on a computer in order to perform automated winding designs for rotating electrical machines. Several examples are provided in order to validate the proposed procedure.

Измерительный орган резервной дистанционной защиты на основе однофазно-многофазных преобразователей

The issues of reserving microprocessor devices for relay protection of critical elements of the electrical network using analog relays are considered. At the same time, for the latter devices, the need to improve operational characteristics is noted. As a solution to this problem, the use of singlephase-multiphase converters of electrical signals of current and voltage based on two coil groups with independent magnetic systems, the determination of their parameters. The use of these converters facilitates the simplification of remote protection relay circuits, the rejection of external power, more accurate regulation of the angle of maximum sensitivity of tripping characteristics and the improvement of operating speed. These advantages allow us to recommend their use as part of analog backup remote protection of transmission lines.

Electronically rotated and translated field‐free line generation for open bore magnetic particle imaging

We propose a coil arrangement for open bore field-free line (FFL) magnetic particle imaging (MPI) system, which is suitable for accessing the subject from the sides. The purpose of this study is twofold, to show that the FFL can be rotated and translated electronically in a volume of interest with this arrangement and to analyze the current, voltage and power requirements for a 1T/m gradient human sized scanner for a 200mm diameter×200mm height cylindrical field of view (FOV). We used split coils side by side with alternating current directions to generate a field-free line. Employing two of these coil groups, one of which is rotated 90 degrees with respect to the other, a rotating FFL was generated. We conducted numerical simulations to show the feasibility of this arrangement for three-dimensional (3D) electronical scan of the FFL. Using simulations, we obtained images of a two-dimensional (2D) in silico dot phantom for a human size scanner with system matrix-based reconstruction. Simulations showed that the FFL can be generated and rotated in one plane and can be translated in two axes, allowing for 3D imaging of a large subject with the proposed arrangement. Human sized scanner required 63-215kW power for the selection field coils to scan the focus inside the FOV. The proposed setup is suitable for FFL MPI imaging with an open bore configuration without the need for mechanical rotation, which is preferable for clinical usage in terms of imaging time and patient access. Further studies are necessary to determine the limitations imposed by peripheral nerve stimulation, and to optimize the system parameters and the sequence design.

Splenic Artery Embolization in Blunt Trauma: A Single-Center Retrospective Comparison of the Use of Gelatin Sponge Versus Coils.

The purpose of this study was to compare the efficacy of gelatin sponge with that of coils for splenic artery embolization in the treatment of blunt splenic injury. A single-center retrospective review was performed with the records of 63 patients (45 men, 18 women; mean age, 45.5 years; range, 16-84 years) with blunt splenic injury treated at a tertiary care trauma center by splenic artery embolization with gelatin sponge (n = 30 patients) or metallic coils (n = 33 patients) between 2005 and 2014. The two groups had comparable median American Association for the Surgery of Trauma grades of IV and comparable angiographic appearances regarding active extravasation and pseudoaneurysm formation at preembolization splenic arteriography (p = 0.32). Clinical outcomes and procedure-related outcomes were evaluated. The success rates were similar in the two groups: splenic artery embolization failed in 6.6% (2/30) of patients in the gelatin sponge group and 12.1% (4/33) in the coil embolization group (p = 0.45; 95% CI, -30.1% to 19.2%). Major complications occurred in six patients (20.0%) in the gelatin sponge group and in six patients (18.1%) in the coil group (p = 0.85; 95% CI, -23.0% to 26.6%). Minor complications occurred in three patients (10.0%) in the gelatin sponge group and seven patients (21.2%) in the coil group (p = 0.21; 95% CI, -35.4% to 14.0%). Procedure time was significantly shorter in the gelatin sponge group (median, 32 minutes; interquartile range, 18-48 minutes) than in the coil group (median, 53 minutes; interquartile range, 30-76 minutes) (p = 0.01). Splenic artery embolization with gelatin sponge appears to be as effective and as safe as coil embolization and can be completed in a shorter time.

Field-reversed configuration formed by in-vessel θ-pinch in a tandem mirror device.

We describe a field reversed configuration (FRC) experiment featuring in-vessel θ-pinch coils and open-field-line plasmas confined in a tandem mirror. Two FRCs, formed near the west and the east mirror throats of a central cell, are ejected toward the mid-plane for colliding and merging. Each FRC consists of four groups of pulsed power supplies and four groups of coils, having diameters 35, 35, 40, and 45 cm. The rise time of the main reversal field is 7.15 μs, and the maximum voltage is 40 kV with total currents of 416 kA, corresponding to a magnetic field of 1690 G. The total capacitive stored energy is 115.2 kJ. A fast pulse gas injection system was designed and tested to inject neutral gas into the FRC formation region with controlled directions. The successful installation of the θ-pinch coils inside the vacuum vessel offers greater freedom for diagnostics and control instruments as well as preserving magnetic tandem mirror configuration. The magnetic field reversal is confirmed by internal magnetic field measurements. The plasma temperature, density, and lifetime are, respectively, ∼100 eV, ∼3.0 × 1018 m-3, and ∼300 μs for the current operating conditions.

Anterior communicating artery aneurysm clipping versus coiling: a comparative study of 50 cases

Abstract Introduction: Aneurysmal Subarachnoid Hemorrhage (aSAH) remains a devastating and often fatal form of stroke. The aneurysm is targeted for obliteration to prevent re-bleeding and to manage the possible complications from the event. Endovascular coiling has emerged as a less invasive alternative to conventional surgical clipping to treat aneurysms. Patients and methods: This study was done in 50 cases of anterior communicating (Acommm) aneurysm presented in the department of neurosurgery, SMS medical college, Jaipur from November 2015 to August 2016 to evaluate the outcome of both modalities used in the treatment of ruptured Acommm aneurysm. 50 patients with Hunt and Hess (H&amp;H) grade I, II or III were classified into two groups of microsurgical clipping and endovascular coiling. Results: Mortality rate was comparable in both groups that were 21. 21% in the clipping group and 23. 52% in the coiling group. Good Glasgow outcome score (GOS) were found in 60. 60% of clipping and 58. 58% of coiling group. All the complications found to be more in clipping group but that were not statistically significant except for hyponatremia which was significantly higher in clipping group(P=0. 007). Conclusion: There was no statistically significant difference in GOS at 6 month of follow up between the two groups. We recommend further interventional studies with larger sample sizes and longer follow up for better evaluation of the modalities.

Endovascular Treatment of Large and Giant Carotid Aneurysms with Flow-Diverter Stents Alone or in Combination with Coils: A Multicenter Experience and Long-Term Follow-up

Although flow diverters (FDs) have been widely accepted by neurointerventionists, their safety has yet to be fully defined. Stratification by aneurysm size and location is essential for correct evaluation of treatment outcomes and risks of flow diversion. To compare neurological and anatomic outcomes and evaluate the risk of complications after endovascular treatment of large or giant internal carotid artery (ICA) aneurysms with FD/FDs alone or together with coil embolization. We reviewed all patients with large or giant, ruptured or unruptured ICA aneurysms who underwent endovascular treatment with flow diversion alone (group A) or with concomitant coiling (group B) in 4 international institutions between 2010 and 2015. Anatomic outcome was evaluated using the Byrne scale on digital subtraction angiography and/or angioMRI and/or angioCT scans 3, 6, 12, and 24 months postoperatively. We collected 44 patients with large or giant ICA aneurysms. Four patients (9%) presented with aneurysmal subarachnoid hemorrhage (SAH). FD/FDs were used alone in 26 patients and in combination with coil embolization in the 18 remaining patients. The mortality rate due to procedure-related and/or neurological complications was 2.2%. Twelve months after the procedure, 88.6% (n = 39) of patients had a favorable neurological outcome. One year after the procedure, the aneurysm was completely occluded in 72.7% of patients: 61.5% (16/18) in group A and 88.9% (16/26) in group B. Clinical outcomes and rates of intraoperative and postoperative complications did not differ significantly between the groups. Better anatomic results using FD/FDs combined with coils were documented 6 months after the procedure; this option seems to provide a higher aneurysm occlusion rate and reduce the need for retreatment.

Efficacy and safety of bronchoscopic lung volume reduction therapy in patients with severe emphysema: a meta-analysis of randomized controlled trials.

BACKGROUNDIncreasing randomized controlled trials (RCTs) indicate that bronchoscopic lung volume reduction (BLVR) is effective for severe emphysema. In this meta-analysis, we investigated the efficacy and safety of BLVR in patients with severe emphysema.METHODSPubMed, Embase and the Cochrane Library and reference lists of related articles were searched, and RCTs that evaluated BLVR therapy VS conventional therapy were included. Meta-analysis was performed only when included RCTs ≥ 2 trials.RESULTSIn total, 3 RCTs for endobronchial coils, 6 RCTs for endobronchial valves (EBV) and 2 RCTs for intrabronchial valves (IBV) were included. Compared with conventional therapy, endobronchial coils showed better response in minimal clinically important difference (MCID) for forced expiratory volume in 1s (FEV1) (RR = 2.37, 95% CI = 1.61 – 3.48, p < 0.0001), for 6-min walk test (6MWT) (RR = 2.05, 95% CI = 1.18 – 3.53, p = 0.01), and for St. George's Respiratory Questionnaire (SGRQ) (RR = 2.32, 95% CI = 1.77 – 3.03, p < 0.00001). EBV therapy also reached clinically significant improvement in FEV1 (RR = 2.96, 95% CI = 1.49 – 5.87, p = 0.002), in 6MWT (RR = 2.90, 95% CI = 1.24 – 6.79, p = 0.01), and in SGRQ (RR = 1.53, 95% CI = 1.22 – 1.92, p = 0.0002). Both coils and EBV treatment achieved statistically significant absolute change in FEV1, 6MWT, and SGRQ from baseline, also accompanied by serious adverse effects. Furthermore, subgroup analysis showed there was no difference between homogeneous and heterogeneous emphysema in coils group. However, IBV group failed to show superior to conventional group.CONCLUSIONSCurrent meta-analysis indicates that coils or EBV treatment could significantly improve pulmonary function, exercise capacity, and quality of life compared with conventional therapy. Coils treatment could be applied in homogeneous emphysema, but further trials are needed.