Similarity metrics for surgical process models

Objective

The objective of this work is to introduce a set of similarity metrics for comparing surgical process models (SPMs). SPMs are progression models of surgical interventions that support quantitative analyses of surgical activities, supporting systems engineering or process optimization.

Methods and materials

Five different similarity metrics are presented and proven. These metrics deal with several dimensions of process compliance in surgery, including granularity, content, time, order, and frequency of surgical activities. The metrics were experimentally validated using 20 clinical data sets each for cataract interventions, craniotomy interventions, and supratentorial tumor resections. The clinical data sets were controllably modified in simulations, which were iterated ten times, resulting in a total of 600 simulated data sets. The simulated data sets were subsequently compared to the original data sets to empirically assess the predictive validity of the metrics.

Results

We show that the results of the metrics for the surgical process models correlate significantly (p < 0.001) with the induced modifications and that all metrics meet predictive validity. The clinical use of the metrics was exemplarily, as demonstrated by assessment of the learning curves of observers during surgical process model acquisition.

Conclusion

Measuring similarity between surgical processes is a complex task. However, metrics for computing the similarity between surgical process models are needed in many uses in the field of medical engineering. These metrics are essential whenever two SPMs need to be compared, such as during the evaluation of technical systems, the education of observers, or the determination of surgical strategies. These metrics are key figures that provide a solid base for medical decisions, such as during validation of sensor systems for use in operating rooms in the future.     

Distinguishing surgical behavior by sequential pattern discovery

ObjectiveEach surgical procedure is unique due to patient’s and also surgeon’s particularities. In this study, we propose a new approach to distinguish surgical behaviors between surgical sites, levels of expertise and individual surgeons thanks to a pattern discovery method.MethodsThe developed approach aims to distinguish surgical behaviors based on shared longest frequent sequential patterns between surgical process models. To allow clustering, we propose a new metric called SLFSP. The approach is validated by comparison with a clustering method using Dynamic Time Warping as a metric to characterize the similarity between surgical process models.ResultsOur method outperformed the existing approach. It was able to make a perfect distinction between surgical sites (accuracy of 100%). We reached an accuracy superior to 90% and 85% for distinguishing levels of expertise and individual surgeons.ConclusionClustering based on shared longest frequent sequential patterns outperformed the previous study based on time analysis.SignificanceThe proposed method shows the feasibility of comparing surgical process models, not only by their duration but also by their structure of activities. Furthermore, patterns may show risky behaviors, which could be an interesting information for surgical training to prevent adverse events.     

Study on treatment of condylar process fractures of the mandible

Treatment of mandibular condylar process fractures may be conservative or surgical. Both treatment approaches aim to reconstruct the articulating joint surfaces in a physiological position to the discoligamentary structures. The study comprised 1812 patients of Wuerzburg University who presented with a fracture of the mandibular condylar process between 1981 and 2001. Besides conservative management options, surgical interventions using mini-plate osteosynthesis and the Wuerzburg lag screw plate were studied for post-treatment changes. Statistical analysis revealed that surgical osteosynthesis is superior to merely conservative therapy in terms of post-treatment dysgnathic severity. Hence, surgical osteosynthesis is advocated especially in patients with high condylar fractures or dislocated fractures in order to ideally achieve 'restitutio ad integrum'.     

Personalized models of bones based on radiographic photogrammetry

The radiographic photogrammetry is applied, for locating anatomical landmarks in space, from their two projected images. The goal of this paper is to define a personalized geometric model of bones, based uniquely on photogrammetric reconstructions. The personalized models of bones are obtained from two successive steps: their functional frameworks are first determined experimentally, then, the 3D bone representation results from modeling techniques. Each bone functional framework is issued from direct measurements upon two radiographic images. These images may be obtained using either perpendicular (spine and sacrum) or oblique incidences (pelvis and lower limb). Frameworks link together their functional axes and punctual landmarks. Each global bone volume is decomposed in several elementary components. Each volumic component is represented by simple geometric shapes. Volumic shapes are articulated to the patient’s bone structure. The volumic personalization is obtained by best fitting the geometric model projections to their real images, using adjustable articulations. Examples are presented to illustrating the technique of personalization of bone volumes, directly issued from the treatment of only two radiographic images. The chosen techniques for treating data are then discussed. The 3D representation of bones completes, for clinical users, the information brought by radiographic images.     

颞骨关节后突的形态学研究

目的:研究颞骨关节后突的形态,提供解剖学资料,为临床参考。方法:观察和测量253例颅骨的颞骨关节后突,并进行分类。结果:颞骨关节后突的出现率为(95.65±1.28)％。依其形态分为结节型、锥体型、乳头型、平顶型和双峰型等五型,其中结节型占(76.86±2.71)％;依其高径分为大、中、小三型,其中中型占(57.02±3.18)％。结论:颞骨关节后突的出现率很高,以结节型为多见,其高径为2～8mm。颞骨关节后突的形态和高径与下颌头后移有关。     

骨科手术模拟训练在运动系统解剖学中的教学实践

正运动系统解剖学是一门和临床骨科紧密联系的课程,对培养学生运动系统的理论知识和实践技能方面起到了重要的作用。该课程传统教学模式是通过标本、挂图、模型以及CAI课件,采取教师讲、学生看,对照课本找组织等方式~([1]),导致学生不能将基础理论与临床实践相结合。而临床技能是体现医生水平的一个重要环节,在当前医患关系紧张,医学生动手机会越来越     

Three-dimensional morphology of the distal femur based on surgical epicondylar axis in the normal elderly population

BackgroundWe aimed to analyze the surface morphology of the distal femur in three dimensions for the healthy elderly, based on the concept that the surgical epicondylar axis (SEA) is a better surrogate for the flexion–extension axis of the knee joint.MethodsWe studied 77 healthy elderly volunteers (40 males and 37 females; age, 68 ± 6 years). The medial and lateral contact lines were calculated three-dimensionally, using the highest points of the medial and lateral condyles in 201 cross-sectional planes around the SEA (every 1°, −60° (hyperextension) to 140° (flexion)). A piecewise fitting function consisting of two linear segments was applied to detect the inflection point of the constant radii in the sagittal plane. The main assessment parameters were knee flexion angle at the inflection point of the radius (inflection angle), mean radius from 0° to the inflection angle (constant radius), and coronal tilt angle of the contact line.ResultsThe inflection angles, constant radii, and coronal tilt angles were 78.2 ± 8.6°, 26.1 ± 2.3 mm, and −0.6 ± 3.2° and 65.6 ± 9.2°, 23.9 ± 2.2 mm, and 6.2 ± 3.2° in the medial and lateral condyles, respectively (all, P < 0.001). The coronal alignment was 88.7 ± 2.2°.ConclusionsThe medial and lateral femoral condyles showed asymmetrical morphologies with the almost ‘constant’ radius of sagittal curvature from 0° to around 80° and 65° of knee flexion, respectively.     

An ontological model of the practice transformation process

Patient-centered medical home is defined as an approach for providing comprehensive primary care that facilitates partnerships between individual patients and their personal providers. The current state of the practice transformation process is ad hoc and no methodological basis exists for transforming a practice into a patient-centered medical home. Practices and hospitals somehow accomplish the transformation and send the transformation information to a certification agency, such as the National Committee for Quality Assurance, completely ignoring the development and maintenance of the processes that keep the medical home concept alive. Many recent studies point out that such a transformation is hard as it requires an ambitious whole-practice reengineering and redesign. As a result, the practices suffer change fatigue in getting the transformation done. In this paper, we focus on the complexities of the practice transformation process and present a robust ontological model for practice transformation. The objective of the model is to create an understanding of the practice transformation process in terms of key process areas and their activities. We describe how our ontology captures the knowledge of the practice transformation process, elicited from domain experts, and also discuss how, in the future, that knowledge could be diffused across stakeholders in a healthcare organization. Our research is the first effort in practice transformation process modeling. To build an ontological model for practice transformation, we adopt the Methontology approach. Based on the literature, we first identify the key process areas essential for a practice transformation process to achieve certification status. Next, we develop the practice transformation ontology by creating key activities and precedence relationships among the key process areas using process maturity concepts. At each step, we employ a panel of domain experts to verify the intermediate representations of the ontology. Finally, we implement a prototype of the practice transformation ontology using Protégé.     

尺骨茎突解剖特点与骨折分型及治疗方法

目的　根据尺骨茎突解剖特点探讨骨折分型与手术治疗方法。 方法 依据腕尺侧副韧带及三角软骨盘在尺骨茎突上的不同止点,将尺骨茎突骨折分为尖端骨折（Ⅰ型）及基底部骨折（Ⅱ型）,按骨折损伤分型分别采用克氏针结合钢丝法、微型螺钉、细钢丝或可吸收线、克氏针等手术方法进行修复。结果 106例患者获得8～42个月（平均15个月）随诊,骨折均获愈合。腕关节功能评定采用Garland和Werley评分法进行评定,优76例,良22例,可6例,差2例。优良率为92.4％。2例尺骨茎突骨折合并桡骨远端骨折,桡骨骨折内固定后,骨折位置丢失,出现短缩畸形,致腕尺侧疼痛,3例固定尺骨茎突骨折之钢丝断裂。 结论 根据尺骨茎突解剖特点对骨折分型,明确受伤发病机制,依据骨折类型采用不同手术方法,对骨折有效、稳定固定,减少并发症出现,允许较早功能锻炼,在骨折愈合及腕关节功能恢复方面有满意的疗效。     

Apofix颈后路内固定治疗齿状突骨折脱位

目的评价Apofix颈后路内固定治疗齿状突骨折脱位的临床疗效。方法对2000年3月-2005年7月收治的16例齿状突骨折脱位患者均行颈后路C1，2Apofix植骨内固定。结果寰枢关节及骨折复位满意，16例皆达到齿状突骨性愈合。结论Apofix内固定手术治疗齿状突骨折脱位手术操作简便，复位固定可靠，恢复快，疗效满意，勿需术中X线定位，适合基层医院推广应用。     

我国脊柱结核外科治疗现状及进展

由于新冠肺炎疫情的暴发，我国的结核病高负担形势较以往更为严重，脊柱结核作为结核病中的高发骨结核疾病，如何规范化治疗成为了当今研究的热点问题。严重的脊柱结核患者，单纯的抗结核药物治疗效果并不理想，此时可以辅以手术治疗，但目前尚无统一的手术标椎，对于手术方案的选择尚无明确定论，本文通过回顾大量相关文献，现对我国脊柱结核外科治疗进展做一概述。     

The assessment of cognitive‐behavioral therapy skills in patients diagnosed with health anxiety: Development and pilot study on an observer‐based rating scale

Cognitive‐behavioral therapy is a highly effective treatment of health anxiety, but it remains unclear through which mechanisms treatment effects prevail. Some evidence suggests that patients acquire skills—understood as techniques helping them reach therapy goals—through psychotherapy. In the current study, an observer‐based rating scale for the skills assessment of patients with health anxiety (SAPH) was developed and validated in a pilot study. Based on 177 videotapes, four independent raters evaluated the frequency of skills acquired during cognitive and exposure therapy among 66 patients diagnosed with health anxiety with the SAPH. Predictive validity was evaluated by the Yale–Brown Obsessive‐Compulsive Scale for Hypochondriasis. The SAPH demonstrated good interrater reliability (ICC_(1,2) = .88, p < .001, 95% CI [.81, .92]) and internal consistency (α = .94). Although patient skills did not significantly increase during three sessions, they significantly predicted a reduction in health anxiety symptoms at the end of treatment (R² = .35). Patients' skills are highly important within the treatment of health anxiety. By providing external ratings of patients' skills with good psychometric properties, our pilot data suggest that the SAPH may complement current tools for the assessment of skills, specifically in targeting health anxiety.     

Guideline validation in multiple trauma care through business process modeling

Clinical guidelines can improve the quality of care in multiple trauma. In our Department of Trauma Surgery a specific guideline is available paper-based as a set of flowcharts. This format is appropriate for the use by experienced physicians but insufficient for electronic support of learning, workflow and process optimization. A formal and logically consistent version represented with a standardized meta-model is necessary for automatic processing. In our project we transferred the paper-based into an electronic format and analyzed the structure with respect to formal errors. Several errors were detected in seven error categories. The errors were corrected to reach a formally and logically consistent process model. In a second step the clinical content of the guideline was revised interactively using a process-modeling tool. Our study reveals that guideline development should be assisted by process modeling tools, which check the content in comparison to a meta-model. The meta-model itself could support the domain experts in formulating their knowledge systematically. To assure sustainability of guideline development a representation independent of specific applications or specific provider is necessary. Then, clinical guidelines could be used for eLearning, process optimization and workflow management additionally.     

Development of a surgical navigation system based on augmented reality using an optical see-through head-mounted display

The surgical navigation system has experienced tremendous development over the past decades for minimizing the risks and improving the precision of the surgery. Nowadays, Augmented Reality (AR)-based surgical navigation is a promising technology for clinical applications. In the AR system, virtual and actual reality are mixed, offering real-time, high-quality visualization of an extensive variety of information to the users (Moussa et al., 2012) [1]. For example, virtual anatomical structures such as soft tissues, blood vessels and nerves can be integrated with the real-world scenario in real time. In this study, an AR-based surgical navigation system (AR-SNS) is developed using an optical see-through HMD (head-mounted display), aiming at improving the safety and reliability of the surgery. With the use of this system, including the calibration of instruments, registration, and the calibration of HMD, the 3D virtual critical anatomical structures in the head-mounted display are aligned with the actual structures of patient in real-world scenario during the intra-operative motion tracking process. The accuracy verification experiment demonstrated that the mean distance and angular errors were respectively 0.809 ± 0.05 mm and 1.038° ± 0.05°, which was sufficient to meet the clinical requirements.     

Intradepartmental consultations in surgical pathology: Review of a standardized process and factors influencing consultation rates and practices in an academic and community hospital setting

Intradepartmental consultations (ICs) are important for quality assurance (QA) and ensuring diagnostic accuracy in surgical pathology. Few studies have reviewed pathologist factors that influence IC rates. Our study reviews IC data and factors that influence both formal (written) and informal (verbal) consultation practices among pathologists in academic and community hospital settings. Formal IC records from the academic hospital were collected and academic and community pathologists were invited to complete a survey about their IC practices. All centers had a formalized process for documenting ICs; however, 92% of academic and 90% of community pathologists also requested informal IC. The top reasons for selecting a particular colleague for IC was perceived level of expertise; however, interpersonal relationships and office proximity had a greater impact on informal IC practice. Top reasons for requesting a formal IC were mandatory (subspecialty defined) consultation and uncertainty regarding pathological findings. Advice on wording was a common reason for informal IC. Written documentation of IC aids in QA and determination of IC metrics; however, informal, undocumented ICs still occur. Reasons for IC and choice of consulting pathologist are multifactorial, and identifying these can help target quality improvement initiatives.     

Animal models in the investigation of anorexia

Anorexia nervosa (AN) is an eating disorder of unknown origin that most commonly occurs in women and usually has its onset in adolescence. Patients with AN invariably have a disturbed body image and an intense fear of weight gain. There is currently no definitive treatment for this disease, which carries a 20% mortality over 20 years. Development of an appropriate animal model of AN has been difficult, as the etiology of this eating disorder likely involves a complex interaction between genetic, environmental, social, and cultural factors. In this review, we focus on several possible rodent models of AN. In our laboratory, we have developed and studied three different mouse models of AN based on clinical profiles of the disease; separation stress, activity, and diet restriction (DR). In addition, we discuss the spontaneous mouse mutation anx/anx and several mouse gene knockout models, which have resulted in an anorexic phenotype. We highlight what has been learned from each of these models and possibilities for future models. It is hoped that a combination of the study of such models, together with genetic and clinical studies in patients, will lead to more rational and successful prevention/treatment of this tragic, and often fatal, disease.     

New models of the oculomotor mechanics based on data obtained with chronic muscle force transducers

Several phenomenological models of the oculomotor mechanics that produce saccadic eye movements have been developed. These models have been based on measurements of macroscopic muscle and orbital tissue properties and measurements of eye kinematics during saccades. We recorded the forces generated by the medial and lateral recti during saccades in an alert, behaving monkey using chronically implanted force transducers. With this new data, we tested the ability of the classic saccade models to generate realistic muscle force profiles. Errors in the predictions of the classic saccade models led to a reexamination of the current models of extraocular muscle. Both a phenomenological, Hill-type muscle model and an approximation to Huxley's molecular level muscle model based on the crossbridge mechanism of contraction (distribution moment model) were derived and studied for monkey extraocular muscle. Simulations of the distribution moment model led to insights suggesting (i) specific modifications in the lumped force/velocity relationship in the Hill-type model that resulted in this type of phenomenological model being able to generate realistic dynamics in extraocular muscle during saccades; (ii) the distribution of activity in the different fiber types in extraocular muscle may be central to the characteristics exhibited by the muscle during saccades; (iii) the transient properties of lengthening muscle such as yielding are not significant during saccades; and (iv) the series elastic component in active muscle may be predominantly generated by the elastic properties of the cross-bridges. This work was supported by National Institutes of Health Grants EY06860, EY06973, and EY06883.     

钩突的解剖观察及在鼻内窥镜下钩突切除术的意义

目的：通过对鼻腔外侧壁的解剖学观察，为功能性鼻内窥镜术最佳手术切口的选择提供依据。方法：对２０例成人头部标本进行解剖观察并对２０２侧钩突切除术进行总结分析。结果：钩突的长度为１８．８±２．２ｍｍ，中段宽度为４．３±０．５ｍｍ，鼻前棘至钩突前缘基部中央的距离为３１．１±２．８ｍｍ。结论：鼻丘、泪骨弓及下鼻甲上缘可作为钩突切除术时定位钩突及选择切口位置的标志。