• Title/Summary/Keyword: Guide stent

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Surgical stent for dental implant using cone beam CT images (콘빔형 전산화단층영상을 이용한 치과임플란트 식립유도장치 개발)

  • Choi, Hyung-Soo;Kim, Gyu-Tae;Choi, Yong-Suk;Hwang, Eui-Hwan
    • Imaging Science in Dentistry
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    • v.40 no.4
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    • pp.171-178
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    • 2010
  • Purpose : The purpose of this study is to develop a surgical stent for dental implant procedure that can be easily applied and affordable by using cone beam computerized tomography (CBCT). Materials and Methods : Aluminum, Teflon-PFA (perfluoroalkoxy), and acetal (polyoxymethylene plastic) were selected as materials for the surgical stent. Among these three materials, the appropriate material was chosen using the CBCT images. The surgical stent, which could be easily placed into an oral cavity, was designed with chosen material. CBCT images of the new surgical stent on mandible were obtained using Alphard-3030 dental CT system (Asahi Roentgen Co., Ltd., Kyoto, Japan). The point of insertion was prescribed on the surgical stent with the multiplanar reconstruction software of OnDemand3D (CyberMed Inc., Seoul, Korea). Guide holes were made at the point of insertion on the surgical stent using newly designed guide jig. CBCT scans was taken for the second time to verify the accuracy of the newly designed surgical stent. Results : Teflon-PFA showed radiologically excellent image characteristics for the surgical stent. High accuracy and reproducibility of implantation were confirmed with the surgical stent. Conclusion : The newly designed surgical stent can lead to the accurate implantation and achieve the clinically predictable result.

Effectiveness of Anchoring with Balloon Guide Catheter and Stent Retriever in Difficult Mechanical Thrombectomy for Large Vessel Occlusion

  • Yi, Ho Jun;Kim, Bum-Tae;Shin, Dong-Sung
    • Journal of Korean Neurosurgical Society
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    • v.65 no.4
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    • pp.514-522
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    • 2022
  • Objective : A distal navigation of a large bore aspiration catheter during mechanical thrombectomy (MT) is important. However, delivering a large bore aspiration catheter is difficult to a tortuous or atherosclerotic artery. We report the experience of anchoring with balloon guide catheter (BGC) and stent retriever to facilitate the passage of an aspiration catheter in MT. Methods : When navigating an aspiration catheter failed with a conventional co-axial microcatheter delivery, an anchoring technique was used. Two types of anchoring technique were applied to facilitate distal navigation of a large bore aspiration catheter during MT. First, a passage of aspiration catheter was attempted with a proximal BGC anchoring technique. If this technique also failed, another anchoring technique with distal stent retriever was tried. Consecutive patients who underwent MT with an anchoring technique were identified. Details of procedure, radiologic outcomes, and safety variables were evaluated. Results : A total of 67 patients underwent MT with an anchoring technique. Initial trial of aspiration catheter passage with proximal BGC anchoring technique was successful for 35 patients (52.2%) and the second trial with distal stent retriever anchoring was successful for 32 patients (47.8%). Overall, navigation of a large bore aspiration catheter was successful for all patients (100%) without any procedure related complications. Conclusion : Our study showed the usefulness of anchoring technique with proximal BGC and distal stent retriever during MT, especially in those with an unfavorable anatomical structure. This technique could be an alternative option for delivering an of aspiration catheter to a distal location.

Flexibile Analysis of Coronary Stents due to Loading Directions (하중 방향에 따른 관상동맥용 스텐트의 유연성 해석)

  • 조승관;조은정;김한성
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.331-334
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    • 2004
  • In clinical use, coronary stents keep coronary arteries open after expansion with a balloon catheter and prevent the expanded artery from collapsing. Coronary stents are positioned in artery by catheter with a balloon along a guide wire to the lesion site. Flexibility is one of important ability for delivery. In this paper, Palmaz-Schatz stent and Tenax complete stent were selected because these are the most representative of tubular stents. Finite element analyses for the stent system were performed using ABAQUS/Standard code. The present study estimated the flexibility of coronary stents due to loading directions. Moreover the present paper suggests a numerical method to test the flexibility of stents. In conclusion this paper shows how the finite element analysis can be effectively organized in the stent development.

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The use of surgical guide stent for implant placement (임플란트 식립을 위한 수술 가이드의 사용)

  • Lee, Ji-Yeon;Yoon, Ji-Young;Oh, Namsik
    • The Journal of Korean Academy of Prosthodontics
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    • v.52 no.4
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    • pp.366-375
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    • 2014
  • Surgical guide not only provide diagnosis and treatment plan, but even location and direction of implantation. Surgical guide could be divided into non-limited design, partially limited design, and completely limited design. Partially limited design is easily manufactured and inexpensive but less accuracy, compared to completely limited design. From this approach, partially limited design may be particularly effective in patients who present with a single missing tooth or partially edentulous teeth. Completely limited design is anatomically accuracy, esthetical and functional, optimized treatment for prosthetic and biomechanical perspective, and also minimizes discomfort for post-treatment. The purpose of this study is to review previous studies of various surgical guides and applying in clinic.

Design of Ultrasonic Vibration Device using PZT Actuator for Precision Laser Machining (압전구동기를 이용한 정밀 가공용 초음파 진동장치 설계)

  • Kim, W.J.;Fei, L.;Cho, S.H.;Park, J.K.;Lee, M.G.
    • Laser Solutions
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    • v.14 no.2
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    • pp.8-12
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    • 2011
  • As the aged population grows around the world, many medical instruments and devices have been developed recently. Among the devices, a drug delivery stent is a medical device which requires precision machining. Conventional drug delivery stent has problems of residual polymer and decoating because the drug is coated on the surface of stent with the polymer. If the drug is impregnated in micro hole array on the surface of the stent, the problem can be solved. Micro sized holes are generally fabricated by laser machining; however, the fabricated holes do not have an enough aspect ratio to contain the drug or a good surface finish to deliver it to blood vessel tissue. To overcome these problems, we propose a vibration-assisted machining mechanism with PZT (Piezoelectric Transducers) for the fabrication of micro sized holes. If the mechanism vibrates the eyepiece of the laser machining head, the laser spot on the workpiece will vibrate vertically because objective lens in the eyepiece shakes by the mechanism's vibration. According to the former researches, the vibrating frequency over 20kHz and amplitude over 500nm are preferable. The vibration mechanism has cylindrical guide, hollowed PZT and supports. In the cylinder, the eyepiece is mounted. The cylindrical guide has upper and low plates and side wall. The shape of plates and side wall are designed to have high resonating frequency and large amplitude of motion. The PZT also is selected to have high actuating force and high speed of motion. The support has symmetrical and rigid characteristics.

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The application of "bone window technique" using piezoelectric saws and a CAD/CAM-guided surgical stent in endodontic microsurgery on a mandibular molar case

  • Kim, Ukseong;Kim, Sunil;Kim, Euiseong
    • Restorative Dentistry and Endodontics
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    • v.45 no.3
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    • pp.27.1-27.9
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    • 2020
  • Apical surgery for a mandibular molar is still challenging for many reasons. This report describes the applications of computer-guided cortical 'bone-window technique' using piezoelectric saws that prevented any nerve damage in performing endodontic microsurgery of a mandibular molar. A 49-year-old woman presented with gumboil on tooth #36 (previously endodontically treated tooth) and was diagnosed with chronic apical abscess. Periapical lesions were confirmed using cone-beam computed tomography (CBCT). Endodontic microsurgery for the mesial and distal roots of tooth #36 was planned. Following the transfer of data of the CBCT images and the scanned cast to an implant surgical planning program, data from both devices were merged. A surgical stent was designed, on the superimposed three-dimensional model, to guide the preparation of a cortical window on the buccal side of tooth #36. Endodontic microsurgery was performed with a printed surgical template. Minimal osteotomy was required and preservation of the buccal cortical plate rendered this endodontic surgery less traumatic. No postoperative complications such as mental nerve damage were reported. Window technique guided by a computer-aided design/computer-aided manufacture based surgical template can be considerably useful in endodontic microsurgery in complicated cases.

In-vitro study on the accuracy of a simple-design CT-guided stent for dental implants

  • Huh, Young-June;Choi, Bo-Ram;Huh, Kyung-Hoe;Yi, Won-Jin;Heo, Min-Suk;Lee, Sam-Sun;Choi, Soon-Chul
    • Imaging Science in Dentistry
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    • v.42 no.3
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    • pp.139-146
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    • 2012
  • Purpose: An individual surgical stent fabricated from computed tomography (CT) data, called a CT-guided stent, would be useful for accurate installation of implants. The purpose of the present study was to introduce a newly developed CT-guided stent with a simple design and evaluate the accuracy of the stent placement. Materials and Methods: A resin template was fabricated from a hog mandible and a specially designed plastic plate, with 4 metal balls inserted in it for radiographic recognition, was attached to the occlusal surface of the template. With the surgical stent applied, CT images were taken, and virtual implants were placed using software. The spatial positions of the virtually positioned implants were acquired and implant guiding holes were drilled into the surgical stent using a specially designed 5-axis drilling machine. The surgical stent was placed on the mandible and CT images were taken again. The discrepancy between the central axis of the drilled holes on the second CT images and the virtually installed implants on the first CT images was evaluated. Results: The deviation of the entry point and angulation of the central axis in the reference plane were $0.47{\pm}0.27$ mm, $0.57{\pm}0.23$ mm, and $0.64{\pm}0.16^{\circ}$, $0.57{\pm}0.15^{\circ}$, respectively. However, for the two different angulations in each group, the $20^{\circ}$ angulation showed a greater error in the deviation of the entry point than did the $10^{\circ}$ angulation. Conclusion: The CT-guided template proposed in this study was highly accurate. It could replace existing implant guide systems to reduce costs and effort.

Analysis of Different Ways of Drainage for Obstructive Jaundice Caused by Hilar Cholangiocarcinoma

  • Xu, Chuan;Lv, Peng-Hua;Huang, Xin-En;Wang, Shu-Xiang;Sun, Ling;Wang, Fu-An
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.14
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    • pp.5617-5620
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    • 2014
  • Objective: To evaluate the prognosis of different ways of drainage for patients with obstructive jaundice caused by hilar cholangiocarcinoma. Materials and Methods: During the period of January 2006- March 2012, percutaneous transhepatic catheter drainage (PTCD)/ percutaneous transhepatic biliary stenting (PTBS) were performed for 89 patients. According to percutaneous transhepatic cholangiography (PTC), external drainage was selected if the region of obstruction could not be passed by guide wire or a metallic stent was inserted if it could. External drainage was the first choice if infection was diagnosed before the procedure, and a metallic stent was inserted in one week after the infection was under control. Selection by new infections, the degree of bilirubin decrease, the change of ALT, the time of recurrence of obstruction, and the survival time of patients as the parameters was conducted to evaluate the methods of different interventional treatments regarding prognosis of patients with hilar obstruction caused by hilar cholangiocarcinoma. Results: PTCD was conducted in 6 patients and PTBS in 7 (p<0.05). Reduction of bilirubin levels and ALT levels was obvious after the procedures (p<0.05). The average survival time with PTCD was 161 days and with PTBS was 243 days (p<0.05). Conclusions: With both drainage procedures for obstructive jaundice caused by hilar cholangiocarcinoma improvement in liver function was obvious. PTBS was found to be better than PTCD for prolonging the patient survival.

Full mouth rehabilitation with Implant-Guided Surgery and Fixed prosthesis (Implant-Guided Surgery를 이용한 고정성 임플란트 보철물의 전악 수복 증례)

  • Kim, Seong-Mo;Park, Jin-Hong;Ryu, Jae-Jun;Shin, Sang Wan;Lee, Jeong-Yol
    • The Journal of Korean Academy of Prosthodontics
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    • v.56 no.2
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    • pp.126-133
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    • 2018
  • The development of cone beam computerized tomography (CBCT) allows three-dimensional analysis of the patient's anatomy. The surgical guide is a combination of CBCT, computer-aided design/computer-aided manufacturing (CAD/CAM) and implant diagnostics software, which allows well planned prostheses design and ideal implant placement. Guided surgery minimizes possible anatomical damage and allows for more reproducible treatment planning. In this case, the operation time was shortened by using a surgical guide for multiple implants placement in a fully edentulous patient. Immediate loading were performed more easily using preliminary preparation of provisional prosthesis. The patient was satisfied with improved esthetics and chewing function.

Role of Balloon Guide Catheter in Modern Endovascular Thrombectomy

  • Chueh, Ju-Yu;Kang, Dong-Hun;Kim, Byung Moon;Gounis, Matthew J.
    • Journal of Korean Neurosurgical Society
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    • v.63 no.1
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    • pp.14-25
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    • 2020
  • Proximal flow control achieved with a balloon guide catheter (BGC) during endovascular treatment of acute ischemic stroke is reviewed in this article. In clinical practice, BGCs offer a multi-faceted approach for clot retrieval by creating proximal flow arrest, reducing embolic burden, and shortening procedure time. Evaluation of frontline thrombectomy procedures with BGCs revealed advantages of combined use over the conventional guide catheter (CGC), notably in the significant reduction of distal emboli to both the affected and previously unaffected territories. Recently, new measures of early and complete reperfusion at first thrombectomy pass have been identified as independent predictors of improved outcomes, which were consistently demonstrated with use of BGC as a safe and effective option to minimize number of passes during intervention. Prior randomized controlled trials reported the positive correlation between BGC-treated patients and a lower risk of mortality as well as shortened procedure time. While BGC use is more common in stent retriever-mediated mechanical thrombectomy, preliminary data has shown the potential benefit of device application during contact aspiration thrombectomy to achieve successful recanalization. However, the question of which major endovascular strategy reigns superior as a frontline remains to be answered. Along with clinical case assessments, BGC performance during in-vitro simulation was analyzed to further understand mechanisms for optimization of thrombectomy technique.