Patient-specific System Research Articles

Personalised 3D Printed high tibial osteotomy achieves a high level of accuracy: 'IDEAL' preclinical stage evaluation of a novel patient specific system.

High tibial osteotomy (HTO) is an effective surgical treatment for isolated medial compartment knee osteoarthritis; however, widespread adoption is limited due to difficulty in achieving the planned correction, and patient dissatisfaction due to soft tissue irritation. The aim of this study was to assess the accuracy of a novel HTO system with 3D printed patient specific implants and surgical guides using cadaveric specimens. Local ethics committee approval was obtained. The novel opening wedge HTO procedure was performed on eight cadaver leg specimens. Whole lower limb CT scans pre- and post-operatively provided geometrical assessment quantifying the discrepancy between pre-planned and post-operative measurements for key variables: the gap opening angle and the patient specific surgical instrumentation positioning. The average discrepancy between the pre-operative plan and the post-operative osteotomy correction angle was: 0.0 ± 0.2° The R² value for the regression correlation was 0.95. The average error in implant positioning was -0.4 ± 4.3 mm, -2.6 ± 3.4 mm and 3.1 ± 1.7° vertically, horizontally, and rotationally respectively. This novel HTO surgery has greater accuracy in correction angle achieved compared to that reported for conventional or other patient specific methods with published data available. This system could potentially improve the accuracy of osteotomy correction angles achieved surgically.

Primary Clinical Research of a Patient Specific Implant System for an Old Zygomaticomaxillary Complex Comminuted Fracture

Primary Clinical Research of a Patient Specific Implant System for an Old Zygomaticomaxillary Complex Comminuted Fracture

Comparison of Changes in the Condylar Volume and Morphology in Skeletal Class III Deformities Undergoing Orthognathic Surgery Using a Customized versus Conventional Miniplate: A Retrospective Analysis.

With the great leap in the development of three-dimensional computer-assisted surgical technology, surgeons can use a variety of assistive methods to achieve better results and evaluate surgical outcomes in detail. This retrospective study aimed to evaluate the postoperative stability after bilateral sagittal split ramus osteotomy by volume rendering methods and to evaluate how postoperative stability differs depending on the type of surgical plate. Of the patients who underwent BSSRO, ten patients in each group (non-customized miniplate and customized miniplate) who met the inclusion criteria were selected. Preoperative and postoperative cone-beam computed tomography data were collected, and condylar morphological and landmark measurements were obtained using Checkpoint and OnDemand software, respectively. The postoperative condylar morphological dataset revealed no significant difference (p > 0.05) between the two groups. No significant difference (p > 0.05) was observed between the two groups in horizontal, vertical, or angular landmark measurements used to quantify operational stability. These results indicate that there is no difference in the surgical outcome between the patient-specific system and the conventional method, which will allow clinicians to take advantage of the patient-specific system for this surgical procedure, with favorable results, as with the conventional method.

Unobtrusive Screening of Central Sleep Apnea From Pressure Sensors Measurements: A Patient-Specific Longitudinal Study

Historically, the lack of patients’ sleep histories has caused low identification of sleep apnea (SA) and referral rates. Moreover, the costly and time-consuming nature of polysomnography (PSG) as a standard clinical test for detecting SA and the lack of sleep clinics has created a demand for suitable home-based monitoring devices. Pressure measurement using a pressure sensitive mat (PSM) can address the challenges found in current sleep-monitoring solutions. The noncontact PSM has a potential to replace obtrusive breathing sensors in the sleep lab and to be used as a prescreening tool for patients suspected of having SA. Applying classical support vector machine (SVM), this article presents a personalized system based on the measurements of each patient to detect central SA (CSA) events and monitor sleep characteristics longitudinally. For this purpose, sensor set-ups were installed in nine seniors’ homes to collect unsupervised pressure data in approximately one year ranging from 8 to 12 months. Cost-based and resampling-based approaches were examined to combat imbalanced data. The results showed that the cost-based method outperformed other methods. Next, the patient-specific system was used to determine the total number of CSA events, as well as their starting time and duration in each day. The SA severity was measured by the central apnea index (CAI). In addition, other sleep characteristics such as bed occupancy (BO), day clock, and night clock were extracted from the PSM measurements. The impact of longitudinal sleep monitoring could be in tracking SA treatment progression, and possibly providing information on the interaction between SA and other disease progressions.

Quantification of human neuromuscular function through optogenetics.

The study of human neuromuscular diseases has traditionally been performed in animal models, due to the difficulty of performing studies in human subjects. Despite the unquestioned value of animal models, inter-species differences hamper the translation of these findings to clinical trials. Tissue-engineered models of the neuromuscular junction (NMJ) allow for the recapitulation of the human physiology in tightly controlled in vitro settings.Methods: Here we report the first human patient-specific tissue-engineered model of the neuromuscular junction (NMJ) that combines stem cell technology with tissue engineering, optogenetics, microfabrication and image processing. The combination of custom-made hardware and software allows for repeated, quantitative measurements of NMJ function in a user-independent manner.Results: We demonstrate the utility of this model for basic and translational research by characterizing in real time the functional changes during physiological and pathological processes.Principal Conclusions: This system holds great potential for the study of neuromuscular diseases and drug screening, allowing for the extraction of quantitative functional data from a human, patient-specific system.

Two auricular epithesis surgical cases retained by a custom titanium implant: result at four years

IntroductionThis article aims at describing the four-year outcome of a surgical procedure implanting a patient specific epithesis system in two patients. Technical noteAfter virtual 3D reconstruction of the anatomy and mirroring of the healthy ear, the position of the three Locator® attachments were optimized in the software to embed them as accurately as possible in the planned episthesis antihelix. The personalized plate bearing the three Locator® implants was then manufactured. Ten osteosynthesis screws were placed around the abutments to ensure bone anchorage. Post-operative antibiotic therapy was prescribed for the duration of ten days. The episthesis was placed two months post-operatively. The follow-up for each patient was 65 and 57 months respectively with no complications to report. Conclusion3D planning assists the surgeon and eliminates several constraints related to the placement of bone implants. It assists the surgical procedure and improves both the aesthetics and functional result of the surgery.

Patient-Specific Guides/Instrumentation in Shoulder Arthroplasty.

Optimal outcomes following total shoulder arthroplasty TSA and reverse shoulder arthroplasty RSA are dependent on proper implant position. Multiple cadaver studies have demonstrated improved accuracy of implant positioning with use of patient-specific guides/instrumentation compared to traditional methods. At this time, there are 3 commercially available single use patient-specific instrumentation systems and 1 commercially available reusable patient-specific instrumentation system. Currently though, there are no studies comparing the clinical outcomes of patient-specific guides to those of traditional methods of glenoid placement, and limited research has been done comparing the accuracy of each system's 3-dimensional planning software. Future work is necessary to elucidate the ideal indications for the use of patient-specific guides and instrumentation, but it is likely, particularly in the setting of advanced glenoid deformity, that these systems will improve a surgeon's ability to put the implant in the best position possible.

Parkinson's Disease Skin Fibroblasts Display Signature Alterations in Growth, Redox Homeostasis, Mitochondrial Function, and Autophagy.

The discovery of biomarkers for Parkinson's disease (PD) is challenging due to the heterogeneous nature of this disorder, and a poor correlation between the underlying pathology and the clinically expressed phenotype. An ideal biomarker would inform on PD-relevant pathological changes via an easily assayed biological characteristic, which reliably tracks clinical symptoms. Human dermal (skin) fibroblasts are accessible peripheral cells that constitute a patient-specific system, which potentially recapitulates the PD chronological and epigenetic aging history. Here, we compared primary skin fibroblasts obtained from individuals diagnosed with late-onset sporadic PD, and healthy age-matched controls. These fibroblasts were studied from fundamental viewpoints of growth and morphology, as well as redox, mitochondrial, and autophagic function. It was observed that fibroblasts from PD subjects had higher growth rates, and appeared distinctly different in terms of morphology and spatial organization in culture, compared to control cells. It was also found that the PD fibroblasts exhibited significantly compromised mitochondrial structure and function when assessed via morphological and oxidative phosphorylation assays. Additionally, a striking increase in baseline macroautophagy levels was seen in cells from PD subjects. Exposure of the skin fibroblasts to physiologically relevant stress, specifically ultraviolet irradiation (UVA), further exaggerated the autophagic dysfunction in the PD cells. Moreover, the PD fibroblasts accumulated higher levels of reactive oxygen species (ROS) coupled with lower cell viability upon UVA treatment. In essence, these studies highlight primary skin fibroblasts as a patient-relevant model that captures fundamental PD molecular mechanisms, and supports their potential utility to develop diagnostic and prognostic biomarkers for the disease.

Abstract ID: 157 Development of Geant4-based patient-specific QA system of gamma knife treatment plans using automated DICOM-RT interface

Gamma knife system which uses 192 small photon beams is widely considered as a very precise modality for intracranial radiosurgery. However, there are still limitations in current treatment planning system (TPS) for accurately estimating the absolute dose in the small volume, or the dose distribution in the inhomogeneous area such as the case of embolization of arteriovenous malformations and the located target volume behind an air cavity [1] . The purpose of this study is to develop quality assurance (QA) system of gamma knife treatment plans based on a patient-specific model constructed by an automated DICOM-RT interface in Geant4. The Leksell Gamma Knife Perfexion was designed in Geant4.10.00 based on the manufacturer’s detailed information. Dose distributions in the spherical water phantom with a diameter of 16 cm were compared between Geant4 and the film measurement for the validation system. For extracting the patient-dependent parameters, automated DICOM-RT interface was developed for constructing the patient-specific model. In-house developed system is able to manually define the physical property of a special volume using the region of interest (ROI) contour data stored in a DICOM file. The dose distributions in the water phantom were compared between Geant4, measurement data and manufacture’s values in terms of full width at half maximum (FWHM). FWHM of Geant4 and measurement were quite well matched with manufacture’s value within 0.3, 0.2 and 0.7 mm in both the x and y direction for 4, 8 and 16 mm, respectively. Furthermore, the dose distributions of Geant4 and commercial TPS were well matched for different beam size combinations for each of the eight sectors. The developed QA system shows the potential to precisely estimate the dose distribution in the patients. In the future, assessment of the absolute dose distribution calculated by Geant4 and commercial TPS for the clinical cases will be performed. Moreover, magnetic resonance (MR) images will be employed in our system for sophisticated modelling the heterogeneities in the patients.

Intrafraction Motion of Patients during Cranial Treatments in Two Different Head Immobilization Systems

To determine the effectiveness of two different methods (reusable or patient specific) for head and neck immobilization during intracranial robotic radiosurgery treatments and infer the consequences of this motion for cone beam image guided treatments on conventional linacs. During intracranial robotic radiosurgery, the patient’s position is evaluated by acquiring a pair of orthogonal x-ray images of their skulls every 30-60 seconds. The robotic arm, on which the radiation treatment unit is mounted, corrects for patient position based on the last pair of images. For this system, the errors introduced by patient motion during treatment can be estimated from the difference between subsequent pairs of images. For most conventional linac treatments, the patient’s position is only determined at the start of treatment using 3D cone-beam imaging. For these systems, errors introduced by patient motion during treatment can also be estimated using the robotic system data, using the difference between the initial position and the average position over the typical duration of treatment (10 minutes). We examined the magnitude of patient motion during treatment for 59 patients using a reusable headrest and 36 patients using a disposable patient specific headrest. The positioning errors were evaluated using a well-known margin recipe which separates patient setup error into random, σ, and systematic, Σ, components. Results are summarised in table 1 for both headrests and both types of treatment modalities.Abstract 3738; Table 1Analysis of residual setup errors due to patient motion during treatment. Errors are estimated for the imaging systems used for the robotic radiosurgery system and for conventional radiation therapy treatments using a reusable headrest or a disposable but patient specific headrestHeadrestTranslational component (mm)Rotational component (degree)σΣMargin (mm)σΣRobotic Radiosurgery TreatmentsDisposable(Patient Specific)0.100.050.20.140.07Reusable0.290.180.60.260.15Conventional TreatmentsDisposable(Patient Specific)0.310.190.70.330.17Reusable0.460.261.00.340.17 Open table in a new tab For robotic radiosurgery treatments, random and systematic errors are approximately three to four times higher for the reusable headrest than for the patient specific system, stressing the importance of precise immobilization for this system, since no margin between the tumour and treated volume is typical. For conventional treatments, the relative differences between the two headrest systems are smaller, but relatively large compared the 3 mm margin currently used in our clinic for brain treatments. Care should be taken when considering changes to clinical practice which can impact the precision of radiation treatments.

Comparison of blood rheological models in patient specific cardiovascular system simulations

Newtonian, Quemada and Casson blood viscosity models are implemented in order to simulate the rheological behavior of blood under pulsating flow conditions in a patient specific iliac bifurcation. The influence of the applied blood constitutive equations is monitored via the wall shear stress (WSS) distribution, magnitude and oscillations, non-Newtonian importance factors, and viscosity values according to the shear rate. The distribution of WSS on the vascular wall follows a pattern which is independent of the rheological model chosen. On the other hand, the WSS magnitude and oscillations are directly related to the blood constitutive equations applied and the shear rate. It is concluded that the Newtonian approximation is satisfactory only in high shear and flow rates. Moreover, the Newtonian model seems to overestimate the possibility for the formation of atherosclerotic lesions or aneurysms at sites of the vascular wall where the WSS are oscillating.

Accuracy and Reproducibility Using Patient-Specific Instrumentation in Total Ankle Arthroplasty.

Implant survivorship is dependent on accuracy of implantation and successful soft tissue balancing. System instrumentation for total ankle arthroplasty implantation has a key influence on surgeon accuracy and reproducibility. The purpose of this study was to determine the accuracy and reproducibility of implant position with patient-specific guides for total ankle arthroplasty across multiple surgeons at multiple facilities. This retrospective, multicenter study included 44 patients who received a total ankle implant (INBONE II Total Ankle System; Wright Medical Technology, Memphis, TN) using PROPHECY patient-specific guides from January 2012 to December 2014. Forty-four patients with an average age of 63.0 years underwent total ankle arthroplasty using this preoperative patient-specific system. Preoperative computed tomography (CT) scans were obtained to assess coronal plane deformity, assess mechanical and anatomic alignment, and build patient-specific guides that referenced bony anatomy. The mean preoperative coronal deformity was 4.6 ± 4.6 degrees (range, 14 degrees varus to 17 degrees valgus). The first postoperative weightbearing radiographs were used to measure coronal and sagittal alignment of the implant vs the anatomic axis of the tibia. In 79.5% of patients, the postoperative implant position of the tibia corresponded to the preoperative plan of the tibia within 3 degrees of the intended target, within 4 degrees in 88.6% of patients, and within 5 degrees in 100% of patients. The tibial component coronal size was correctly predicted in 98% of cases, whereas the talar component was correctly predicted in 80% of cases. The use of patient-specific instrumentation for total ankle arthroplasty provided reliable alignment and reproducibility in the clinical situation similar to that shown in cadaveric testing. This study has shown that the preoperative patient-specific instrumentation provided for accuracy and reproducibility of ankle arthroplasty implantation in a cohort across multiple surgeons and facilities. Level III, retrospective comparative series.

Évaluation des effets potentiellement délétères d’exercices de l’épaule en fonction des pathologies rencontrées

Background Shoulder strength training exercises represent a major component of rehabilitation protocols designed for conservative or post-surgical management of shoulder pathologies. Numerous methods are described for exercising each shoulder muscle or muscle group. Limited information is available to assess potential deleterious effects of individual methods in respect to specific shoulder pathologies. Objectives To use a patient specific 3D motion capture system for evaluation of a set of shoulder strength training exercises regarding glenohumeral, labral and subacromial compression as well as elongation of individual rotator cuff muscles. Methods One healthy right-handed male volunteer (28 years old, 180 cm, 80 kg) participated to the study. The outcome of interest was the impact of a set of common shoulder rehabilitation exercises on articular cartilages and labrum compression, subacromial space height, and rotator cuff elongation. After 3D reconstruction, a kinematic evaluation according to a previously validated protocol was used. Results According to the type of strengthening exercise, important variations in glenoid cartilage and labrum compression, subacromial space height and tendons elongation were observed, as indicated by the calculated P-values below the significance level at P > 0.05. Glenoid cartilage compression varied up to 1.98 mm and labral compression up to 1.80 mm, with maximal average penetration depths obtained during the strengthening of middle/inferior trapezius, deltoid, supraspinatus, infraspinatus and teres minor. Exercises performed with TheraBand™ had the lowest impact on cartilages compression, whereas exercises executed with the body weight induced the greatest penetration depths. Contacts were all located between the antero- and postero-superior sectors of the glenoid. Minimal subacromial height ranged between 0.15 mm to 3.60 mm in average for targeted muscles exercises according to the training technique used. Least favorable target muscles training with respect to subacromial space height were serratus, biceps brachii, pectoralis major and supraspinatus. Overhead strength training resulted in significant decrease (P = 0.001) of subacromial space height. Conclusion To our knowledge, this study represents the first screening of shoulder strengthening exercises to identify potential deleterious effects on the shoulder joint Motion capture allows for reliable assessment of glenohumeral, labral and subacromial compression as well as tendon muscle elongation during shoulder strength training exercises. Data may be used to design rehabilitation protocols specific to shoulder pathological states.

SU‐F‐T‐479: Estimation of the Accuracy in Respiratory‐Gated Radiotherapy

Purpose:Irregular respiratory patterns affects dose outputs in respiratorygated radiotherapy and there is no commercially available quality assurance (QA) system for it. We designed and developed a patient specific QA system for respiratory‐gated radiotherapy to estimate irradiated output.Methods:Our in‐house QA system for gating was composed of a personal computer with the USB‐FSIO electronic circuit connecting to the linear accelerator (ONCOR‐K, Toshiba Medical Systems). The linac implements a respiratory gating system (AZ‐733V, Anzai Medical). During the beam was on, 4.2 V square‐wave pulses were continually sent to the system. Our system can receive and count the pulses. At first, our system and an oscilloscope were compared to check the performance of our system. Next, basic estimation models were generated when ionization‐chamber measurements were performed in gating using regular sinusoidal wave patterns (2.0, 2.5, 4.0, 8.0, 15 sec/cycle). During gated irradiation with the regular patterns, the number of the pulses per one gating window was measured using our system. Correlation between the number of the pulses per one gating and dose per the gating window were assessed to generate the estimation model. Finally, two irregular respiratory patterns were created and the accuracy of the estimation was evaluated.Results:Compared to the oscilloscope, our system worked similarly. The basic models were generated with the accuracy within 0.1%. The results of the gated irradiations with two irregular respiratory patterns show good agreement within 0.4% estimation accuracy.Conclusion:Our developed system shows good estimation for even irregular respiration patterns. The system would be a useful tool to verify the output for respiratory‐gated radiotherapy.

EP-1987: Feasibility study of patient specific QA system for HDR brachytherapy in cervical cancer

EP-1987: Feasibility study of patient specific QA system for HDR brachytherapy in cervical cancer

A novel integrated patient specific instrumentation system and its application for total knee arthroplasty

Objective To study the accuracy of preoperative planning and postoperative satisfaction of prosthesis position by applying the personal surgical cutting guide (PSCG) to total knee arthroscopy (TKA) based on 3D printing technique. Methods In this randomized study, 20 patients were selected from August 2014 to October 2015, who were randomly divided into two groups. In PSCG group, 4 males and 6 females were enrolled, with a mean age of 70.9±6.69 (from 59 to 78) years. In conventional instrumentation group, 2 males and 8 females were enrolled, with a mean age of 69.9±6.35 (from 58 to 77) years. The conventional instrumentation group was treated with conventional TKA, while the PSCG group was treated with personal surgical cutting guides. Then the knee valgus angle of patients, the angle between prosthesis components on the coronal and the sagittal plane of two groups were evaluated. Subsequently the correlation of the actual osteotomy amount, the valgus angle, caster angle, external rotation angle between intra- and preoperative planning were compared in the PSCG group. Results Compared with the ideal value of each angle, the mean deviation of the hip-knee-ankle angle 0.77°±0.51°, frontal femoral component angle 0.37°± 0.53° and frontal tibial component angle 0.11°±0.24° showed statistically significant difference between two groups (P 0.05). The actual osteotomy amount, the valgus angle, caster angle, external rotation angle correlated well between intra- and preoperative planning (t=-2.547, 3.864, 0.537, -0.040, -1.290,P >0.05). Conclusion TKA assisted by PSCG can make lower extremity alignment and accuracy of prosthesis implantation more accurate compared with conventional TKA, especially in hip-knee-ankle angle, frontal femoral component angle and frontal tibial component angle. Key words: Arthroplasty, replacement, knee; Individuality; Imaging, three-dimensional

Automatic 3D modeling and simulation of bone-fixator system in a novel graphical user interface

Abstract External ring fixators are widely used in orthopaedics for the purposes of fracture fixation, bone lengthening and deformity correction. In these fixators, the clinician typically brings the bone fragments to an anatomically desired position by changing the lengths of the rods connecting the fixator rings. This task is accomplished by the clinician based on experience and expertise. As an alternative, commercial systems exist where the same task is automatized with the help of an accompanying software that implements a mathematical model of the fixator. In this work, we have developed a graphical user interface (GUI) implementing a mathematical theory introduced previously. The GUI also allows visualization and simulation of the patient specific bone-fixator system, something that lacks in the available software systems. The information gathered from the bone X-ray images is used to convert a canonical bone model to the patient-specific bone model. This conversion algorithm has been tested on eight different bone models and found to be effective. The visualization tool has been used in the simulation of two orthopaedic procedures, one involving a tibia and the other a femur. In both examples, the visualization tool has provided a realistic depiction of the treatment procedure. We believe that the developed GUI equipped with the visualization module could be a useful clinical tool where the clinician can visualize the applied treatment or evaluate different treatment scenarios a priori per patient.

Development of a patient-specific 3D dose evaluation program for QA in radiation therapy

We present preliminary results for a 3-dimensional dose evaluation software system ( P DRESS, patient-specific 3-dimensional dose real evaluation system). Scanned computed tomography (CT) images obtained by using dosimetry were transferred to the radiation treatment planning system (ECLIPSE, VARIAN, Palo Alto, CA) where the intensity modulated radiation therapy (IMRT) nasopharynx plan was designed. We used a 10 MV photon beam (CLiX, VARIAN, Palo Alto, CA) to deliver the nasopharynx treatment plan. After irradiation, the TENOMAG dosimeter was scanned using a VISTA™ scanner. The scanned data were reconstructed using VistaRecon software to obtain a 3D dose distribution of the optical density. An optical-CT scanner was used to readout the dose distribution in the gel dosimeter. Moreover, we developed the P DRESS by using Flatform, which were developed by our group, to display the 3D dose distribution by loading the DICOM RT data which are exported from the radiotherapy treatment plan (RTP) and the optical-CT reconstructed VFF file, into the independent P DRESS with an ioniz ation chamber and EBT film was used to compare the dose distribution calculated from the RTP with that measured by using a gel dosimeter. The agreement between the normalized EBT, the gel dosimeter and RTP data was evaluated using both qualitative and quantitative methods, such as the isodose distribution, dose difference, point value, and profile. The profiles showed good agreement between the RTP data and the gel dosimeter data, and the precision of the dose distribution was within ±3%. The results from this study showed significantly discrepancies between the dose distribution calculated from the treatment plan and the dose distribution measured by a TENOMAG gel and by scanning with an optical CT scanner. The 3D dose evaluation software system ( P DRESS, patient specific dose real evaluation system), which were developed in this study evaluates the accuracies of the three-dimensional dose distributions. Further applications of the system utility are expected to result from future studies.

GS1-27 Patient-specific display system to assist diagnostic treatment of occlusal disease(GS1: Cell and Tissue Biomechanics VI)

GS1-27 Patient-specific display system to assist diagnostic treatment of occlusal disease(GS1: Cell and Tissue Biomechanics VI)

Integrated Dynamic Physiological Model for Drug Infusion Simulation Studies

This work presents a dynamic model that integrates some of the main processes of the human physiology. It is aimed at simulating the behavior of most relevant variables in response to the administration of typical drugs used in medical procedures. The model integrates the following submodels available in the open literature: (i) cardiovascular, (ii) baroreflex, (iii) respiration, (iv) transport and distribution of substances, (v) pharmacological effects of drugs. The integrated model has a difficult mathematical structure due to the nonlinearity present in most relationships and the occurrence of time events associated with heart valves and other discontinuous phenomena. An efficient computational implementation was developed in the Fortran programming language and applied to several case studies. The results are in reasonable agreement with published experimental data although further studies are required to improve the model accuracy for real applications. The simulation model can be used as a computational tool for medical training and off-line diagnosis, as well as the basis for a patient specific online decision support system.