首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Toward CT-based facial fracture treatment   总被引:2,自引:0,他引:2  
Facial fractures have formerly been classified solely by anatomic location. CT scans now identify the exact fracture pattern in a specific area. Fracture patterns are classified as low, middle, or high energy, defined solely by the pattern of segmentation and displacement in the CT scan. Exposure and fixation relate directly to the fracture pattern for each anatomic area of the face, including frontal bone, frontal sinus, zygoma, nose, nasoethmoidal-orbital region, midface, and mandible. Fractures with little comminution and displacement were accompanied by subtle symptoms and required simple treatment; middle-energy injuries were treated by standard surgical approaches and rigid fixation. Highly comminuted fractures were accompanied by dramatic instability and marked alterations in facial architecture; only multiple surgical approaches to fully visualize the "buttress" system provided alignment and fixation. Classification of facial fractures by (1) anatomic location and (2) pattern of comminution and displacement define refined guidelines for exposure and fixation.  相似文献   

2.
3.
The data on 187 patients with traumatic lesions of the ankle joint and foot were used to analyze the capacities of computed tomography (CT) in the diagnosis of this pathology. The efficiency of CT versus X-ray study was evaluated. Specific guidelines are given to make spital CT. CT is shown to be of the most informative value in the diagnosis of lesions of the tibial plateau, undisplaced fractures of the internal malleolus, small marginal comminuted fractures, and lesions of the distal tibiofibular syndesmosis. There is evidence for that CT plays a dominant role in the diagnosis of lesions of the talus and calcaneus. Emphasis is laid on the great value of secondary multi- and three-dimensional image reconstructions.  相似文献   

4.
This prospective study compared the sensitivity of panoramic tomography (zonography) and helical computed tomography (CT) in diagnosing 73 mandibular fractures in 42 consecutive patients and correlated the results with known surgical findings. The purpose of the study was to determine the optimal radiologic examination for the diagnosis and operative management of mandibular fractures. The attending surgeons' interpretations of panoramic tomograms and helical CT images in the axial plane were compared with the patients' known surgical findings. A series of questions assessed the relative contribution of these two radiologic examinations in formulating an optimal operative plan for each patient. In the 42 patients studied, the sensitivity of helical CT was 100 percent in diagnosing mandibular fractures; this compared with 86 percent (36 of 42) for panoramic tomography, in which significantly more fractures were missed (p = 0.0412). In the six patients with fractures not visualized, the operative management was altered because of the new fracture visualized on helical CT. Of the seven missed fractures, six were in the posterior portion of the mandible. Comparing fracture detection by region, seven fractures found on helical CT were not visualized on panoramic tomography. Helical CT improved the understanding of the nature of mandibular fractures by providing additional information regarding fracture displacement and comminution and by locating injuries missed using panoramic tomography. This study suggests that helical CT alone may be more diagnostic than panoramic tomography alone in evaluating mandibular fractures. Helical CT sufficiently demonstrated details of fractures in 41 of 42 patients; in one patient, the nature of a dental root fracture was better delineated by panoramic tomography.  相似文献   

5.
To develop an understanding of the expected functional outcomes after facial trauma, a retrospective cohort study of patients with complex facial fractures was conducted. A cohort of adults aged 18 to 55 years who were admitted to the R. Adams Cowley Shock Trauma Center between July of 1986 and July of 1994 for treatment of a Le Fort midface fracture (resulting from blunt force) was retrospectively identified.Outcomes of interest included measures of general health status and psychosocial well being in addition to self-reported somatic symptoms. General health status was ascertained using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). The Body Satisfaction Scale was used to define patient concerns about altered body image and shape. To determine whether complex maxillofacial trauma and facial fractures contributed to altered social interactions, the Social Avoidance and Distress scale was used. In addition, information about a patient, his or her injury, and its treatment were ascertained from the medical records.Using the methods described above, 265 patients with Le Fort fractures were identified. These individuals were matched to a similar group of 242 general injury patients. A total of 190 of the Le Fort patients (72 percent of those eligible for the study) and 144 (60 percent) general injury patients were successfully located, and long-term interview data were acquired.Le Fort fracture patients as a group had similar health status outcomes when compared with the group of general injury patients. However, when outcomes were examined by the complexity of the Le Fort fracture, the authors found that study subjects with severe, comminuted Le Fort injuries (group D) had significantly lower SF-36 scores (worse outcomes) for the two dimensions related to role limitations: role limitations due to physical problems and role limitations due to emotional problems (p < 0.05). SF-36 scores for all other dimensions except physical function were also lower for comminuted versus less complex Le Fort fractures, although differences were not statistically significant.Specifically, there was a direct relationship between severity of facial injury and patients reporting work disability. Of group C and D Le Fort patients (severely comminuted fractures) only 55 and 58 percent, respectively, had returned to work at the time of follow-up interview. These figures are significantly lower than the back-to-work percentage of patients with less severe facial injury (70 percent).When study participants were asked if they were experiencing specific somatic symptoms at the time of the interview that they had not experienced before the injury, a significantly larger percent of the Le Fort fracture patients (compared with the general injury patients) responded in the affirmative. Differences between the Le Fort fracture and general injury groups were statistically significant (p < 0.05) for all 11 symptoms.The percentage of patients reporting complaints increased with increasing complexity of facial fracture in the areas of visual problems, alterations in smell, difficulty with mastication, difficulty with breathing, and epiphora, and these differences reached statistical significance.Patients sustaining comminuted Le Fort facial fractures report poorer health outcomes than patients with less severe facial injury and substantially worse outcomes than population norms. It is also this severely injured population that reports the greatest percentage of injury-related disability, preventing employment at long-term follow-up. The long-term goal of centralized tertiary trauma treatment centers must be to return the patient to a productive, active lifestyle.  相似文献   

6.
摘要 目的:对比桥接组合式内固定系统(OBS)结合Nice结与锁定钢板治疗锁骨中段粉碎性骨折的疗效。方法:回顾性选取2021年6月至2022年1月间在我院接受治疗的锁骨中段粉碎性骨折患者(n=66)的临床资料。根据手术方式的不同将患者分为A组(锁定钢板治疗,32例)和B组(桥接组合式内固定系统结合Nice结,34例),对比两组临床症状恢复情况、并发症发生率、视觉疼痛模拟评分(VAS)、Constant-Murley评分和肩关节活动度。结果:两组骨折愈合时间对比无差异(P>0.05)。B组术中出血量少于A组,手术时间短于A组(P<0.05)。两组术后3个月Constant-Murley评分升高,VAS评分下降(P<0.05),B组术后3个月VAS评分低于A组,Constant-Murley评分高于A组(P<0.05)。两组术后3个月前屈、后伸、内旋、外旋的肩关节活动度增大(P<0.05),且B组术后3个月前屈、后伸、内旋、外旋的肩关节活动度均大于A组(P<0.05)。两组并发症发生率组间比较无统计学差异(P>0.05)。结论:OBS与锁定钢板治疗锁骨中段粉碎性骨折相比,OBS结合Nice结治疗可减少术中出血量,缩短手术时间,促进骨折愈合,扩大肩关节活动度,改善肩关节功能,疗效更好。  相似文献   

7.
The patterns of midface fractures were related to postoperative computed tomography scans and clinical results to assess the value of ordering fracture assembly in success of treatment methods. A total of 550 midface fractures were studied for their midface components and the presence of fractures in the adjacent frontal bone or mandible. Preoperative and postoperative computed tomography scans were analyzed to generate recommendations regarding exposure and postoperative stability related to fracture pattern and treatment sequence, both within the midface alone and when combined with frontal bone and mandibular fractures. Large segment (Le Fort I, II, and III) fractures were seen in 68 patients (12 percent); more comminuted midface fracture combinations were seen in 93 patients (17 percent). Midface and mandibular fractures were seen in 166 patients (30 percent). Midface, mandible, and nasoethmoid fractures were seen in 38 patients (7 percent). Frontal bone and midface fractures were seen in 131 patients (24 percent). Split-palate fractures accompanied 8 percent of midface fractures. Frontal bone, midface, and mandibular fractures were seen in 54 patients (10 percent). The midface, because of weak bone structure and comminuted fracture pattern, must therefore be considered a dependent, less stable structure. Its injuries more commonly occur with fractures of the frontal bone or mandible (two-thirds of cases) and, more often than not (>60 percent), are comminuted. Comminuted and pan-facial (multiple area) fractures deserve individualized consideration regarding the length of intermaxillary immobilization. Examples of common errors are described from this patient experience.  相似文献   

8.
The purpose of the study presented here was to investigate the manufacturability of human anatomical models from Computed Tomography (CT) scan data via a 3D desktop printer which uses fused deposition modelling (FDM) technology. First, Digital Imaging and Communications in Medicine (DICOM) CT scan data were converted to 3D Standard Triangle Language (STL) format by using InVaselius digital imaging program. Once this STL file is obtained, a 3D physical version of the anatomical model can be fabricated by a desktop 3D FDM printer. As a case study, a patient’s skull CT scan data was considered, and a tangible version of the skull was manufactured by a 3D FDM desktop printer. During the 3D printing process, the skull was built using acrylonitrile-butadiene-styrene (ABS) co-polymer plastic. The printed model showed that the 3D FDM printing technology is able to fabricate anatomical models with high accuracy. As a result, the skull model can be used for preoperative surgical planning, medical training activities, implant design and simulation to show the potential of the FDM technology in medical field. It will also improve communication between medical stuff and patients. Current result indicates that a 3D desktop printer which uses FDM technology can be used to obtain accurate anatomical models.  相似文献   

9.
Finite element (FE) modelling has been proposed as a tool for estimating fracture risk and patient-specific FE models are commonly based on computed tomography (CT). Here, we present a novel method to automatically create personalised 3D models from standard 2D hip radiographs. A set of geometrical parameters of the femur were determined from seven ap hip radiographs and compared to the 3D femoral shape obtained from CT as training material; the error in reconstructing the 3D model from the 2D radiographs was assessed. Using the geometry parameters as the input, the 3D shape of another 21 femora was built and meshed, separating a cortical and trabecular compartment. The material properties were derived from the homogeneity index assessed by texture analysis of the radiographs, with focus on the principal tensile and compressive trabecular systems. The ability of these FE models to predict failure load as determined by experimental biomechanical testing was evaluated and compared to the predictive ability of DXA. The average reconstruction error of the 3D models was 1.77 mm (±1.17 mm), with the error being smallest in the femoral head and neck, and greatest in the trochanter. The correlation of the FE predicted failure load with the experimental failure load was r2=64% for the reconstruction FE model, which was significantly better (p<0.05) than that for DXA (r2=24%). This novel method for automatically constructing a patient-specific 3D finite element model from standard 2D radiographs shows encouraging results in estimating patient-specific failure loads.  相似文献   

10.
When closed manipulation fails to restore articular congruity in comminuted, displaced fractures of the distal radius, open reduction and internal fixation is required. Results of surgical stabilization and articular reconstruction of these injuries are reviewed in this retrospective study of 49 patients with 52 displaced, intra-articular distal radius fractures. Forty-three patients (87%) with a mean age of 37 years (range of 17 to 79 years) were available for evaluation. The mean follow-up time was 38 months (range 22-69 months). When rated according to the Association for the Study of Internal Fixation (ASIF), 19 were type C2 and 21 were type C3. We devised an Injury Score System based on the initial injury radiographs to classify severely comminuted intra-articular fractures and to identify those associated with carpal injury (3 patients). Post-operative fracture alignment, articular congruity, and radial length were significantly improved following surgery (p < .01). Grip strength averaged 69% +/- 22% of the contralateral side, and the range of motion averaged 75% +/- 18% of the contralateral side post-operatively. A combined outcome rating system that included grip strength, range of motion, and pain relief averaged 76% +/- 19% of the contralateral side. There was a statistically significant decrease in the combined rating with more severe fracture patterns as defined by the ASIF system (p < .01), Malone classification (p < .03), and the Injury Score System (p < .001). The Injury Score System presented here, and in particular the number of fracture fragments, correlated most closely with outcome of all the classification systems studied. Operative treatment of these distal radius fractures with reconstruction of the articular congruity and correction of the articular surface alignment with internal fixation and/or external fixation, can significantly improve the radiographic alignment and functional outcome. Furthermore, the degree to which articular stepoff, gap between fragments, and radial shortening are improved by surgery is strongly correlated with improved outcome, even when the results are corrected for severity of initial injury, whereas correction of radial tilt or dorsal tilt did not correlate with improved outcome.  相似文献   

11.
目的:观察脐带间充质干细胞治疗粉碎性骨折的疗效和安全性。方法:将脐带间充质干细胞通静脉输注和局部多点注射到常规治疗效果欠佳自愿接受干细胞移植的1例粉碎性骨折患者,4次为一个疗程,每周间隔1次,每次治疗细胞总数(3~7)×107。术后1、3、6月定期观察患者临床症状及影像学的变化并进行动态观察。结果:脐带间充质干细胞治疗后一月,患者在不帮助的情况下可独立缓慢行走,复查X线提示骨折部位有新生骨形成;干细胞治疗后三月,复查X线提示骨折愈合较前好转;半年后,患者右下肢受力明显好转,可以独立自由行走,复查X线提示右下肢骨折部位有连续性骨痂形成,骨折部位愈合良好。结论:脐带间充质干细胞移植治疗粉碎性骨折是一种安全、有效的手段,可促进粉碎性骨折的愈合,改善其生活质量。  相似文献   

12.
Biplane 2D-3D registration approaches have been used for measuring 3D, in vivo glenohumeral (GH) joint kinematics. Computed tomography (CT) has become the gold standard for reconstructing 3D bone models, as it provides high geometric accuracy and similar tissue contrast to video-radiography. Alternatively, magnetic resonance imaging (MRI) would not expose subjects to radiation and provides the ability to add cartilage and other soft tissues to the models. However, the accuracy of MRI-based 2D-3D registration for quantifying glenohumeral kinematics is unknown. We developed an automatic 2D-3D registration program that works with both CT- and MRI-based image volumes for quantifying joint motions. The purpose of this study was to use the proposed 2D-3D auto-registration algorithm to describe the humerus and scapula tracking accuracy of CT- and MRI-based registration relative to radiostereometric analysis (RSA) during dynamic biplanar video-radiography. The GH kinematic accuracy (RMS error) was 0.6–1.0 mm and 0.6–2.2° for the CT-based registration and 1.4–2.2 mm and 1.2–2.6° for MRI-based registration. Higher kinematic accuracy of CT-based registration was expected as MRI provides lower spatial resolution and bone contrast as compared to CT and suffers from spatial distortions. However, the MRI-based registration is within an acceptable accuracy for many clinical research questions.  相似文献   

13.
The purpose of the study was to test the precision and accuracy of a method used to track selected landmarks during motion of the temporomandibular joint (TMJ). A precision phantom device was constructed and relative motions between two rigid bodies on the phantom device were measured using optoelectronic (OE) and electromagnetic (EM) motion tracking devices. The motion recordings were also combined with a 3D CT image for each type of motion tracking system (EM+CT and OE+CT) to mimic methods used in previous studies. In the OE and EM data collections, specific landmarks on the rigid bodies were determined using digitization. In the EM+CT and OE+CT data sets, the landmark locations were obtained from the CT images. 3D linear distances and 3D curvilinear path distances were calculated for the points. The accuracy and precision for all 4 methods were evaluated (EM, OE, EM+CT and OE+CT). In addition, results were compared with and without the CT imaging (EM vs. EM+CT, OE vs. OE+CT). All systems overestimated the actual 3D curvilinear path lengths. All systems also underestimated the actual rotation values. The accuracy of all methods was within 0.5mm for 3D curvilinear path calculations, 0.05mm for 3D linear distance calculations and 0.2 degrees for rotation calculations. In addition, Bland-Altman plots for each configuration of the systems suggest that measurements obtained from either system are repeatable and comparable.  相似文献   

14.
Nasal bone fractures are the most common among facial fractures and are the third most common fractures in the human frame. Although many forms of treatment have been introduced, controversy regarding the optimal treatment still remains. Nasal bone fractures are complex, with significantly varying types that are often undermanaged in closed reduction procedures. The authors' experiences with nasal bone fractures have shown that the baseline for surgical intervention depends on the type of fracture and the method of maintenance after reduction, both of which have considerable impact on the final result. Therefore, it is very important and challenging to determine the proper method of reduction and maintenance. The periosteal covering plays an important role in the splinting action after closed reduction, but sagging, depression, and instability remain major complications in some cases. The authors devised a new method of accurate, firm stabilization of the fractured nasal bone by using external pins in those unfavorable fractures determined radiologically to gain optimal reduction and fixation. In the present study, fractures were grouped into favorable and unfavorable fractures, the latter being those that remained unstable or impacted even after reduction and thus needed open reduction. Unfavorable fractures were divided into four subclasses according to radiologic findings: (1) type I (frontal), including chip or tip fractures, which often depress the upper lateral cartilage and tend to sag after reduction; (2) type II (lateral), or laterally depressed segmental fractures with a lateral shift of the arch in fragments or as a unit; (3) type III (mixed), or type II with septal involvement; and (4) type IV (complex), including open or multiple comminuted fractures. After an initial evaluation to determine the fracture type, closed reduction and external fixation were performed for types I, II, and III fractures and open reduction was performed for type IV fractures 5 to 7 days after the fracture. Closed reduction with the use of external pins was done in eight cases: type I (two), type II (four), and type III (two). The mean age of the patients was 27.8 years, and the average follow-up period was 11.7 months. Functional and aesthetic results were satisfactory. This new method for support and fixation is an alternative to the conventional closed reduction and a promising way to prevent secondary deformity.  相似文献   

15.
Surgery for mandibular condyle fractures must allow direct vision of the fracture, reduce surgical trauma and achieve reduction and fixation while avoiding facial nerve injury. This prospective study was conducted to introduce a new surgical approach for open reduction and internal fixation of mandibular condyle fractures using a modified transparotid approach via the parotid mini-incision, and surgical outcomes were evaluated. The modified transparotid approach via the parotid mini-incision was applied and rigid internal fixation using a small titanium plate was carried out for 36 mandibular condyle fractures in 31 cases. Postoperative follow-up of patients ranged from 3 to 26 months; in the first 3 months after surgery, outcomes for all patients were analyzed by evaluating the degree of mouth opening, occlusal relationship, facial nerve function and results of imaging studies. The occlusal relationships were excellent in all patients and none had symptoms of intraoperative ipsilateral facial nerve injury. The mean degree of mouth opening was 4.0 (maximum 4.8 cm, minimum 3.0 cm). No mandibular deviations were noted in any patient during mouth opening. CT showed complete anatomical reduction of the mandibular condyle fracture in all patients. The modified transparotid approach via the smaller, easily concealed parotid mini-incision is minimally invasive and achieves anatomical reduction and rigid internal fixation with a simplified procedure that directly exposes the fracture site. Study results showed that this procedure is safe and feasible for treating mandibular condyle fracture, and offers a short operative path, protection of the facial nerve and satisfactory aesthetic outcomes.  相似文献   

16.
目的:探讨利用股骨近端抗旋髓内钉法治疗老年股骨转子下粉碎性骨折的临床效果,为临床提供参考。方法:对我院2009年6月-2013年1月收治的38例老年股骨转子下粉碎性骨折患者行股骨近端抗旋髓内钉法进行手术治疗,分析手术方法、效果及患者的预后效果。结果:28例行闭合复位,7例行骨折端切开复位,患者术后7-14d可下地活动,3 m内扶拐部分负重行走,31例(88.6%)获得随访,随访时间9-24个月,骨折愈合时间为3-6个月,平均3.7个月;Harris髋功能评分标准:优18例,良10例,中3例,优良率90.32%(28/31)。结论:PFNA是一种治疗老年股骨转子下粉碎性骨折的有效装置,能够减少骨折不愈合、髋内翻畸形愈合及内固定断裂、切割股骨头等并发症,在治疗老年股骨转子下粉碎性骨折时可达到较高的骨愈合率、较快的功能恢复。  相似文献   

17.
Recently, we reported obtaining tomograms of meibomian glands from healthy volunteers using commercial anterior segment optical coherence tomography (AS-OCT), which is widely employed in clinics for examination of the anterior segment. However, we could not create 3D images of the meibomian glands, because the commercial OCT does not have a 3D reconstruction function. In this study we report the creation of 3D images of the meibomian glands by reconstructing the tomograms of these glands using high speed Fourier-Domain OCT (FD-OCT) developed in our laboratory. This research was jointly undertaken at the Department of Ophthalmology, Seoul St. Mary''s Hospital (Seoul, Korea) and the Advanced Photonics Research Institute of Gwangju Institute of Science and Technology (Gwangju, Korea) with two healthy volunteers and seven patients with meibomian gland dysfunction. A real time imaging FD-OCT system based on a high-speed wavelength swept laser was developed that had a spectral bandwidth of 100 nm at the 1310 nm center wavelength. The axial resolution was 5 µm and the lateral resolution was 13 µm in air. Using this device, the meibomian glands of nine subjects were examined. A series of tomograms from the upper eyelid measuring 5 mm (from left to right, B-scan) × 2 mm (from upper part to lower part, C-scan) were collected. Three-D images of the meibomian glands were then reconstructed using 3D “data visualization, analysis, and modeling software”. Established infrared meibography was also performed for comparison. The 3D images of healthy subjects clearly showed the meibomian glands, which looked similar to bunches of grapes. These results were consistent with previous infrared meibography results. The meibomian glands were parallel to each other, and the saccular acini were clearly visible. Here we report the successful production of 3D images of human meibomian glands by reconstructing tomograms of these glands with high speed FD-OCT.  相似文献   

18.
目的:探讨不同类型的桡骨远端骨折的有效治疗方法。方法:分析106例桡骨远端骨折,分别采用闭合手法复位,切开复位或有限切开复位内固定方法,分别对骨折复位比较及功能评分。结果:完整随访106例桡骨远端骨折病例,随访时间3~21个月。对保守治疗组与手术治疗组进行骨折复位测定及改良Garland和Werley评分,A,B型骨折无显著性差异;C型骨折中,手术组明显优于保守治疗组。结论:对于C型骨折,建议行切开复位内固定治疗;对于A,B型需根据实际情况选择治疗方式。  相似文献   

19.
Vitamin D metabolites are able to change plasma calcitonin (CT) levels, but nothing is known about a possible effect at the CT gene level. Here we have investigated the acute effects of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on the CT biosynthetic activity of thyroid glands from adult rats. Plasma CT levels were significantly increased (X2) 1 and 2 h after 1,25-(OH)2D3 injection in the face of unchanged plasma calcium values. The thyroidal CT content also was unchanged. A 2-fold increase in CT mRNA level measured by dot-blot hybridization occurred 1 and 2 h after 1,25-(OH)2D3 administration. Expression of CT gene products was examined in the rabbit reticulocyte lysate cell-free translation assay. After polyacrylamide gel electrophoresis, specific immunoprecipitates were autoradiographed and quantified by integration. A single precursor of Mr approximately equal to 15 000 could be specifically immunoprecipitated with CT antisera. A 3-4-fold rise in translatable CT mRNA activity was observed 1 and 2 h after 1,25-(OH)2D3 injection. Thus, parallel changes in CT mRNA level, CT mRNA activity and plasma CT levels were observed in adult female rats after administration of 1,25-(OH)2D3. These findings demonstrate for the first time that 1,25-(OH)2D3 enhanced CT gene expression in the face of unchanged plasma calcium levels.  相似文献   

20.
Advances in intra-operative imaging and the development of new minimally invasive techniques are having an ever greater impact on modern surgery. Mobile CT scanners in the operating room is a new technique that permits image-guided surgery, and helps minimize postoperative complications. We report on our initial experience with intraoperative CT scanning during surgery on patients suffering lateral midface trauma. A mobile CT unit, the Tomoscan M (Philips, Utrecht, Netherlands) set up in the operating room, was evaluated in 6 patients with zygomatic bone fractures. The patients were placed on the CT scanner table, which is detachable from the gantry. The unit is powered by batteries charged from an ordinary ring mains supply via a conventional plug. The CT images obtained were of good quality in all cases. No technical problems were observed during surgery. Using repeat CT scans, the procedure also permits accurate intraoperative monitoring of the anatomical repositioning of the bone fragments, and accurate implantation. No intraoperative or early postoperative complications were observed. This new technical aid ensures highly accurate reduction of the bone fragments, and minimizes the need for reoperation. High-quality intraoperative imaging with surgical navigation increase surgical outcome, and expand the spectrum of minimally invasive surgery.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号