3D Planning Research Articles

The influence of the weight-bearing state on three-dimensional (3D) planning in lower extremity realignment – analysis of novel vs. state-of-the-art planning approaches

BackgroundThe use of 3D planning to guide corrective osteotomies of the lower extremity is increasing in clinical practice. The use of computer-tomography (CT) data acquired in supine position neglects the weight-bearing (WB) state and the gold standard in 3D planning involves the manual adaption of the surgical plan after considering the WB state in long-leg radiographs (LLR). However, this process is subjective and dependent on the surgeons experience. A more standardized and automated method could reduce variability and decrease costs.PurposeThe aim of the study was (1) to compare three different three-dimensional (3D) planning modalities for medial open-wedge high tibial osteotomy (MOWHTO) and (2) to describe the current practice of adapting NWB CT data after considering the WB state in LLR. The purpose of this study is to validate a new, standardized approach to include the WB state into the 3D planning and to compare this method against the current gold standard of 3D planning. Our hypothesis is that the correction is comparable to the gold standard, but shows less variability due compared to the more subjective hybrid approach.MethodsThree surgical planning modalities were retrospectively analyzed in 43 legs scheduled for MOWHTO between 2015 and 2019. The planning modalities included: (1) 3D hybrid (3D non-weight-bearing (NWB) CT models after manual adaption of the opening angle considering the WB state in LLR, (2) 3D NWB (3D NWB CT models) and (3) 3D WB (2D/3D registration of 3D NWB CT models onto LLR to simulate the WB state). The pre- and postoperative hip-knee-ankle angle (HKA) and the planned opening angle (°) were assessed and differences among modalities reported. The relationship between the reported differences and BMI, preoperative HKA (LLR), medial meniscus extrusion, Outerbridge osteoarthritis grade and joint line convergence angle (JLCA) was analyzed.ResultsThe mean (std) planned opening angle of 3D hybrid did not differ between 3D hybrid and 3D WB (0.4 ± 2.1°) (n.s.) but was higher in 3D hybrid compared to 3D NWB (1.1° ± 1.1°) (p = 0.039). 3D WB demonstrated increased preoperative varus deformity compared to 3D NWB: 6.7 ± 3.8° vs. 5.6 ± 2.7° (p = 0.029). Patients with an increased varus deformity in 3D WB compared to 3D NWB (> 2 °) demonstrated more extensive varus alignment in LLR (p = 0.009) and a higher JLCA (p = 0.013).ConclusionSmall intermodal differences between the current practice of the reported 3D hybrid planning modality and a 3D WB approach using a 2D/3D registration algorithm were reported. In contrast, neglecting the WB state underestimates preoperative varus deformity and results in a smaller planned opening angle. This leads to potential under correction in MOWHTO, especially in patients with extensive varus deformities or JLCA.Clinical RelevanceIncorporating the WB state in 3D planning modalities has the potential to increase accuracy and lead to a more consistent and reliable planning in MOWHTO. The inclusion of the WB state in automatized surgical planning algorithms has the potential to reduce costs and time in the future.

The Value of Computed Tomography-Based Planning in Shoulder Arthroplasty Compared to Intra-/Interobserver Reliability of X-ray Planning.

Background: Reversed total shoulder arthroplasty (RTSA) is an established surgery for many pathologies of the shoulder and the demand continues to rise with an aging population. Preoperative planning is mandatory to support the surgeon's understanding of the patient's individual anatomy and, therefore, is crucial for the patient's outcome. Methods: In this observational study, we identified 30 patients who underwent RTSA with two- and three-dimensional preoperative planning. Each patient underwent new two-dimensional planning from a medical student and an orthopedic resident as well as through a mid-volume and high-volume shoulder surgeon, which was repeated after a minimum of 4 weeks. The intra- and interobserver reliability was then analyzed and compared to the 3D planning and the implanted prosthesis. The evaluated parameters were the size of the pegged glenoid baseplate, glenosphere, and humeral short stem. Results: The inter-rater reliability showed higher deviations in all four raters compared to the 3D planning of the base plate, glenosphere, and shaft. The intra-rater reliability showed a better correlation in more experienced raters, especially in the planning of the shaft. Conclusions: Our study shows that 3D planning is more accurate than traditional planning on plain X-rays, despite experienced shoulder surgeons showing better results in 2D planning than inexperienced ones.

Quality Assessment Radiotherapy Planning of Breast Cancer Patients with Built-In Metal Port Implants

Purpose: To evaluate the quality of radiation planning for breast cancer patients with implants with a built-in metal port. Conduct a quantitative analysis of the quality of planning, assess the dose load on critical organs for this category of patients.Material and methods: Homogeneity and conformity indices were calculated, and dose loads in critical organs were assessed for irradiation plans using 3D conformal RT (3D CRT) technology for 23 breast cancer patients with a built-in metal port implants. Calculations were carried out both taking into account (outlining) the metal port and artifacts from it on CT images, and without taking it into account.Results: Based on the results of the analysis of the calculated values of conformity and homogeneity indices, doses in critical organs of irradiation plans for 23 patients with breast cancer, it was shown that the presence of a metal port and artifacts from it affects the nature of the dose distribution.Conclusions: When creating a 3D CRT treatment plan, it is necessary to delineate the metal port and artifacts and assign true densities.

3D maxillofacial surgery planning - one decade development of technology.

Nowadays, techniques and the use of patient specific implants seem to be the recent high technology standard in reconstructive surgery. Surgery planning is as old as the surgery procedures themselves. Any good surgeon, before entering the operating theatre, has a plan for how to proceed. It is based on knowledge and experience in combination of evaluation of all case relevant information. In fact, virtual surgery planning and CAD/CAM reflects the technological "state of the art" into the medical daily practice. Recently, 3D printing technologies became easy and accessible for everyone. Virtual 3D images substituted the plaster models, the film profile analysis switched to digital, 3D printed bone models of the case helped to understand the morphology of the deformity and prepare the osteotomies with "hands on the bone". The authors' own 20 years of experience on surgical planning, the development of digital technologies in oral and maxillofacial surgery is traced and comments on case examples are presented.

The Sum of the Leg Length Discrepancy and the Difference in Global Femoral Offset Is Equal to That of the Contralateral Intact Side and Improves Postoperative Outcomes after Total Hip Arthroplasty: A Three-Dimensional Analysis.

Background/Objectives: Global femoral offset (GFO) and leg length discrepancy (LLD) affect outcomes after total hip arthroplasty (THA). Moreover, the sum of the difference in GFO between the THA and non-surgical sides and LLD (SGL) reportedly affects the outcomes in a two-dimensional evaluation. We examined the association of the GFO, LLD, and SGL with the Harris Hip Score (HHS) using a three-dimensional (3D) evaluation. Methods: We retrospectively surveyed 172 patients with hemilateral hip osteoarthritis who underwent THA. The GFO, LLD, and SGL were measured using the 3D pelvis and femur models; these models were adjusted for the pelvis and femur, and the coordinate systems were parallelized. Furthermore, their relationship with the modified HHS (mHHS) 1 year after THA was determined. Results: Significant correlations were found among mHHS, GFO, and SGL in the binomial group, whereas LLD was not significantly correlated. The optimal values of GFO and SGL were 1.01 mm and 0.18 mm/100 cm body height, respectively, which were considered optimal when the SGL values were approximately equal to those of the non-operative side. The optimal ranges for GFO and SGL were -1.65 to 3.67 mm and -4.78 to 5.14 mm/100 cm, respectively. Conclusions: Our findings were obtained after adjusting the pelvis and femur to a unified coordinate system. Therefore, the results of this study can be directly applied to 3D planning.

Anatomical cup implantation assisted with dynamic 3D planning improves functional outcomes in primary total hip arthroplasty: A retrospective study.

Anatomical cup implantation is a promising approach in primary total hip arthroplasty (THA) and improves functional outcomes. We aimed to evaluate the cup position and functional outcomes in primary THA with preoperative dynamic 3D planning. We retrospectively reviewed 54 hips in 48 patients who underwent primary THA with anatomical cup implantation (mean follow-up time: 52months). Cup positions were evaluated based on patient-specific morphology, the acetabular fossa and the combined anteversion test. Functional outcomes were assessed after THA. The paired-sample t-test was performed for surgical and contralateral native hips among 42 patients who underwent unilateral THA. Two hips suffered intraoperative trochanteric fracture, but no hip dislocations occurred. No patients reported groin or thigh pain, and all patients were capable of deep squatting and one-leg standing. The mean Harris hip score, WOMAC score, and physical SF-36 score were 94.46 ± 6.16, 10.41 ± 3.62, and 95.19 ± 8.74, respectively. Except for acetabular offset, THA restored biomechanics to those of contralateral native hip, including cup anteversion, abduction, femoral offset and acetabular height (P> 0.05). This study provided evidence for the application of anatomical cup implantation assisted with dynamic 3D planning in primary THA, which restored morphology and improved functional outcomes.

Effective Differences between 2D and 3D Planned Brachytherapy in Lung Cancer: An Institutional Retrospective Study.

Background and Objectives: Advanced lung cancer is usually manifested by endoluminal tumor propagation, resulting in central airway obstruction. The objective of this study is to compare the high dose rate brachytherapy treatment outcomes in non-small-cell lung cancer (NSCLC) depending on the treatment planning pattern-two-dimension (2D) or three-dimension (3D) treatment planning. Materials and Methods: The study was retrospective and two groups of patients were compared in it (a group of 101 patients who underwent 2D planned high-dose-rate endobronchial brachytherapy (HDR-EBBT) in 2017/18 and a group of 83 patients who underwent 3D planned HDR-EBBT between January 2021 and June 2023). Results: In the group of 3D planned brachytherapy patients, there was a significant improvement in terms of loss of symptoms of bronchial obstruction (p = 0.038), but no improvement in terms of ECOG PS (European Cooperative Oncology Group Performance Status) of the patient (p = 0.847) and loss of lung atelectasis (if there was any at the beginning of the disease) (p = 0.781). Two-year overall survival and time-to-progression periods were similar for both groups of patients (p = 0.110 and 0.154). Fewer treatment complications were observed, and 91.4% were in 3D planned brachytherapy (BT) patients. Conclusions: Three-dimensionally planned HDR-EBBT is a suggestive, effective palliative method for the disobstruction of large airways caused by endobronchial lung tumor growth. Independent or more often combined with other types of specific oncological treatment, it certainly leads to the loss of symptoms caused by bronchial obstruction and the improvement of the quality of life of patients with advanced NSCLC. Complications of the procedure with 3D planning are less compared to 2D planned HDR-EBBT.

Application and evaluation of artificial intelligence 3D preoperative planning software in developmental dysplasia of the hip

BackgroundAccurate preoperative planning is crucial for successful total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH). The aim of this study was to compare the accuracy of an artificial intelligence-assisted three-dimensional (3D) planning system (AIHIP) with two-dimensional templates in predicting acetabular cup size in THA for DDH.MethodThis study retrospectively analyzed image data from 103 DDH patients who had THA between May 2019 and August 2023. AIHIP was used for 3D planning, and two-dimensional (2D) templates were used by two experienced surgeons. Accuracy was assessed by comparing predicted and actual cup sizes, and potential factors affecting accuracy were analyzed, including gender, side, BMI, and dysplasia classification.ResultsAIHIP had higher accuracy in predicting the acetabular cup size compared to the 2D template. Within ± 0 size, AIHIP’s accuracy was 84.1%, while the 2D template’s was 64.0% (p < 0.05). Within ± 1 size, AIHIP's accuracy was 95.1%, while the 2D template’s was 81.1% (p < 0.05). Accuracy was unaffected by gender, side, or BMI but was by DDH classification. In subgroup analysis, AIHIP's mean absolute error (0.21 ± 0.54) was significantly lower than the 2D template’s (0.62 ± 0.95) for Crowe II and Crowe III (p < 0.05).ConclusionAIHIP is superior to 2D templates in predicting the acetabular cup size accurately for THA in DDH patients. AIHIP may be especially beneficial for Crowe II and III DDH patients, as 2D templates may not accurately predict cup size in these cases.

Pre-selection blade size choice for the microsurgical clipping of cerebral artery aneurysms: A numerical study

BackgroundBrain strokes comprise the third leading cause of death worldwide. Microsurgical clipping is recognized as being one of the most effective approaches to the treatment of brain aneurysms. The incomplete closure of the distal-side aneurysm neck is the most common cause of the persistent filling of the dome. Since the diameter of the neck increases when the neck of the aneurysm is squeezed closed by the blades of the clip, the blades should be correspondingly longer. This study provided an assessment of whether the presurgical selection of clips using a 3D planning system is feasible in terms of selecting the most suitable clip for aneurysm occlusion. MethodsThe computational model was created based on computer tomography data obtained from nine brain aneurysms. The closing of the aneurysm was provided in two steps. The first the length of the blades used for closing corresponded to the length of the aneurysm neck as confirmed by the radiological measurements. The second the length of the blades was adjusted according to stage one, so as to determine the minimum required for the closure of all the gaps in the interior space of the aneurysm neck. ResultsNo differences were detected between the radiological measurement of the aneurysm neck size and the measurements obtained from the reconstructed stereolithographic 3D models. It was observed that the size of the aneurysm neck increased following clipping by 40% to 60% of its original size. The larger the aneurysm neck, the greater the deformation of the aneurysm. ConclusionFirstly, the 3D reconstruction of CT/MRI data did not result in any loss of accuracy and the measurement of the neck of the aneurysm was the same for both of the methods employed. The second, and more important, outcome was that the deformation of the neck of the cerebral aneurysm is at least 1.4x greater than its original size. This information is essential in terms of the pre-selection of the size of the clip.

Real-time Reconstruction of Comminuted Mandibular Fractures Using 3D Printing.

Comminuted fractures of the jaws are complex injuries requiring special attention. In the past, treatment included closed reduction using maxillomandibular fixation. With advancements in technology and fixation systems, open reduction became a prevalent option. These fractures are difficult to reconstruct during the primary treatment phase, thus resulting in higher complication rates. The introduction of three-dimensional (3D) planning and printing brought about superior outcomes, yet these focus on secondary reconstruction due to the need for outsourcing planning and titanium printing. In this report, we describe real-time in-house 3D planning and printing using computer-assisted design software and a 3D-fused deposition printer for virtual reduction of the comminuted fractures and printing of the reconstructed mandible. Following virtual 3D reduction, the newly created mandibles were 3D printed. The model was then used to preband a reconstruction plate, which in turn was used as a template during surgery for reducing the segments. The process of virtual reduction and printing should take a couple of hours at most. The results of five cases showed good alignment and proper function. Three-dimensional technology can be applied in the everyday primary care treatment protocol of comminuted fractures as an in-house tool which greatly improves both functional and aesthetic outcomes.

The clinical value of preoperative 3D planning and 3D surgical guides for Imhäuser osteotomy in slipped capital femoral epipysis: a retrospective study

BackgroundAccurate repositioning of the femoral head in patients with Slipped Capital Femoral Epiphysis (SCFE) undergoing Imhäuser osteotomy is very challenging. The objective of this study is to determine if preoperative 3D planning and a 3D-printed surgical guide improve the accuracy of the placement of the femoral head.MethodsThis retrospective study compared outcome parameters of patients who underwent a classic Imhäuser osteotomy from 2009 to 2013 with those who underwent an Imhäuser osteotomy using 3D preoperative planning and 3D-printed surgical guides from 2014 to 2021. The primary endpoint was improvement in Range of Motion (ROM) of the hip. Secondary outcomes were radiographic improvement (Southwick angle), patient-reported clinical outcomes regarding hip and psychosocial complaints assessed with two questionnaires and duration of surgery.ResultsIn the 14 patients of the 3D group radiographic improvement was slightly greater and duration of surgery was slightly shorter than in the 7 patients of the classis Imhäuser group. No difference was found in the ROM, and patient reported clinical outcomes were slightly less favourable.ConclusionsSurprisingly we didn’t find a significant difference between the two groups. Further research on the use of 3D planning an 3D-printed surgical guides is needed.Trial registrationApproval for this study was obtained of the local ethics committees of both hospitals.

3D Path Planning of the Solar Powered UAV in the Urban-Mountainous Environment with Multi-Objective and Multi-Constraint Based on the Enhanced Sparrow Search Algorithm Incorporating the Levy Flight Strategy

In response to practical application challenges in utilizing solar-powered unmanned aerial vehicle (UAV) for remote sensing, this study presents a three-dimensional path planning method tailored for urban-mountainous environment. Taking into account constraints related to the solar-powered UAV, terrain, and mission objectives, a multi-objective trajectory optimization model is transferred into a single-objective optimization problem with weight factors and multi-constraint and is developed with a focus on three key indicators: minimizing trajectory length, maximizing energy flow efficiency, and minimizing regional risk levels. Additionally, an enhanced sparrow search algorithm incorporating the Levy flight strategy (SSA-Levy) is introduced to address trajectory planning challenges in such complex environments. Through simulation, the proposed algorithm is compared with particle swarm optimization (PSO) and the regular sparrow search algorithm (SSA) across 17 standard test functions and a simplified simulation of urban-mountainous environments. The results of the simulation demonstrate the superior effectiveness of the designed improved SSA based on the Levy flight strategy for solving the established single-objective trajectory optimization model.

Determination of optimal component positioning in THA using 3D preoperative planning.

Advancements in three-dimensional (3D) preoperative planning tools can offer surgeons and design engineers detailed feedback and additional opportunities for clinical advancements. The objective of this study is to use a 3D total hip arthroplasty preoperative planning tool to compare femoral component alignment for three different stem systems. The planning tool in this study used morphology data of femoral bones gathered from a CT database, seven from postoperative patients and 63 from statistical shape models (SSMs), to suggest specific implant sizes and optimal placements in 3D to match each specific bone model. Retrospective validations of predicted stem size and femoral version were first performed by comparing planner-chosen and surgeon-implanted stem sizes and version angles for the seven postoperative patients. Next, the alignment of three different stem systems was evaluated using bone models generated from SSMs, with a quantitative focus on component head positioning. In the validation study, the planner accurately selected stem size and orientation compared to the surgeon for all assessed subjects. In the stem evaluation, the three stem systems yielded different accuracies in component placement, with the newest stem system demonstrating the closest restoration of anatomical head center location. It is evident that new stem designs may have the potential for increased accuracy over their predecessors, demonstrating that new stem designs can offer improved intraoperative and postoperative alignment potential. The 3D preoperative planning tools can provide novel and reliable data to both surgeons and design engineers, which can ultimately improve clinical outcomes and future implant designs.

An IMRT planning technique for treating whole breast or chest wall with regional lymph nodes on Halcyon and Ethos.

Field size limitations on Halcyon and Ethos treatment machines largely preclude use of the conventional monoisocentric three-field technique for breast/chest wall and regional lymph nodes. We present an alternative, IMRT-based planning approach that facilitates treatment on Halcyon and Ethos while preserving plan quality. Eight breast and regional node cases (four left-sided, four right-sided) were planned for an Ethos machine using a 15-17 field IMRT technique. Institutional plan quality metrics for CTV and PTV coverage and OAR sparing were assessed. Five plans (four right-sided, one left-sided) were also planned using a hybrid 3D multisocenter technique. CTV coverage and OAR sparing were compared to the IMRT plans. Eclipse scripting tools were developed to aid in beam placement and plan evaluation through a set of dosimetric scorecards, and both are shared publicly. On average, the IMRT plans achieved breast CTV and PTV coverage at 50Gy of 97.9% and 95.7%, respectively. Supraclavicular CTV and PTV coverages at 45Gy were 100% and 95.5%. Axillary lymph node CTV and PTV coverages at 45Gy were 100% and 97.1%, and IMN CTV coverage at 45Gy was 99.2%. Mean ipsilateral lung V20 Gy was 19.3%, and average mean heart dose was 1.6Gy for right-sided cases and 3.0Gy for left-sided. In comparison to the hybrid 3D plans, IMRT plans achieved higher breast and supraclavicular CTV coverage (99.9%vs. 98.6% and 99.9%vs. 93.4%), higher IMN coverage (99.6%vs. 78.2%), and lower ipsilateral lung V20 Gy (19.6%vs. 28.2%). Institutional plan quality benchmarks were achieved for all eight cases using the IMRT-based planning approach. The IMRT-based planning approach offered superior conformity and OAR sparing than a competing hybrid 3D approach.

Adaptive Ant Colony Optimization with Sub-Population and Fuzzy Logic for 3D Laser Scanning Path Planning.

For the precise measurement of complex surfaces, determining the position, direction, and path of a laser sensor probe is crucial before obtaining exact measurements. Accurate surface measurement hinges on modifying the overtures of a laser sensor and planning the scan path of the point laser displacement sensor probe to optimize the alignment of its measurement velocity and accuracy. This manuscript proposes a 3D surface laser scanning path planning technique that utilizes adaptive ant colony optimization with sub-population and fuzzy logic (SFACO), which involves the consideration of the measurement point layout, probe attitude, and path planning. Firstly, this study is based on a four-coordinate measuring machine paired with a point laser displacement sensor probe. The laser scanning four-coordinate measuring instrument is used to establish a coordinate system, and the relationship between them is transformed. The readings of each axis of the object being measured under the normal measuring attitude are then reversed through the coordinate system transformation, thus resulting in the optimal measuring attitude. The nominal distance matrix, which demonstrates the significance of the optimal measuring attitude, is then created based on the readings of all the points to be measured. Subsequently, a fuzzy ACO algorithm that integrates multiple swarm adaptive and dynamic domain structures is suggested to enhance the algorithm's performance by refining and utilizing multiple swarm adaptive and fuzzy operators. The efficacy of the algorithm is verified through experiments with 13 popular TSP benchmark datasets, thereby demonstrating the complexity of the SFACO approach. Ultimately, the path planning problem of surface 3D laser scanning measurement is addressed by employing the proposed SFACO algorithm in conjunction with a nominal distance matrix.

The Scalloped Surgical Guide as an Alternative to Flat Bone Reduction Guide in Full-arch Implant Restoration.

The goal of this clinical report was to present an alternative to traditional flat bone reduction guides, using a custom-designed 3D printed guide according to the future gingival margin of the planned dentition. A 61-year-old female with concerns regarding her smile appearance was presented. The initial examination revealed excessive gingival show accompanied by excessive overjet. The dentition was in a failing situation. The proposed treatment plan, relying on the sufficient amount of bone and keratinized tissue, consisted of re-contouring of the alveolar ridge and gingiva and placement of six implants and a FP-1 prosthesis after extraction of all remaining maxillary teeth. Digital smile design was completed, and a fully-digitally-guided surgery was planned. This consisted of utilizing three surgical guides. Starting with the fixation pin guide and continuing with the scalloped hard and soft tissue reduction guide and finally, the implant placement template. Following the surgery, the patient received a temporary restoration and on the 4-month follow-up, a new poly-methyl meta-acrylate temporary prosthesis was delivered. The patient's 7-month follow-up is presented in the paper. The report of this triple-template guided surgery indicated that digital 3D planning is a considerably predictable tool to properly establish and evaluate future occlusal plane, smile line, and lip support. Scalloped guides seem to be an excellent alternative to conventional bone reduction guides since they require less bone removal and improve patient comfort during surgery.

Tibial tuberosity-trochlear groove distance is significantly decreased by medial closing wedge distal femoral osteotomy.

While medial closing wedge distal femoral osteotomy (MCWDFO) has been used to address patella instability combined with valgus malalignment, its impact on patellofemoral parameters remains uncharted. Hence, this study seeks to establish a three-dimensional (3D) planning of MCWDFO and measure its effect on the tibial tubercle - trochlear groove distance (TTTG) through simulation and calculation. MCWDFO with a stepwise increment of one-degree varisation (1°-15°) was performed on 3D surface models of 14 lower extremities with valgus malalignment and 24 lower extremities with neutral alignment of the lower limb, resulting in a total of 608 simulations. Anatomic landmarks were employed to measure hip-knee-ankle angle (HKA), TTTG, and femoral torsion for each simulation. A mathematical formula was adopted to calculate TTTG changes following MCWDFO, and subsequently the mean simulated and calculated TTTG values were compared. Following a standardised protocol, MCWDFO was performed without rotational changes. MCWDFO exhibited an almost linear reduction in TTTG, at a rate of approximately -1.05 ± 0.13 mm per 1° of varisation, demonstrating a strong negative correlation (R = -0.83; p < 0.001). Limb alignment did not exert an influence on TTTG change; however, it correlated with tibial plateau width. The mean difference between the simulated and calculated TTTG values amounted to 0.03 ± 0.03 mm per 1° varisation (p < 0.001). The TTTG distance is linearly reduced by 1.05 mm for every 1° of varisation within the varus correction range of 0°-15° during MCWDFO. Patients with combined valgus and patellar instability may benefit from MCWDFO due to frequently pathological TTTG. Level III, descriptive laboratory study.

Is there a difference in surgical accuracy following bimaxillary surgery between cleft and non-cleft patients?

To assess the surgical accuracy of 3D virtually planned orthognathic surgery among patients with and without cleft. This retrospective cohort study included cleft and non-cleft patients with class III malocclusion who underwent bimaxillary surgery. CBCT scans were acquired before and immediately after surgery. 3D virtual surgical planning (VSP) was performed using CBCT and digitalized dentition data. All orthognathic surgeries were performed by the same surgeons using interocclusal splints. The primary outcome variable was surgical accuracy, defined as the difference between the planned and surgically achieved maxillary movements, quantified in six degrees of freedom. Analysis of covariance was used to test for intergroup differences in surgical accuracy after correcting for differences in the magnitude of planned surgical maxillary movements. Twenty-eight cleft and 33 non-cleft patients were enrolled, with mean ages of 18.5 and 25.4 years, respectively (P=0.01). No significant gender difference was present between the groups (P=0.10). After adjustment for small differences in surgical movements, no significant differences in surgical accuracy were observed between cleft and non-cleft patients. The present study demonstrates that high surgical accuracy in maxillary movements can be achieved in both cleft and non-cleft patients using VSP and interocclusal splints. Orthognathic cases with cleft can be performed with 3D VSP to obtain a satisfactory surgical accuracy.

3D surgical planning including patient-specific drilling guides for tibial plateau fractures.

Proper preoperative planning benefits fracture reduction, fixation, and stability in tibial plateau fracture surgery. We developed and clinically implemented a novel workflow for 3D surgical planning including patient-specific drilling guides in tibial plateau fracture surgery. A prospective feasibility study was performed in which consecutive tibial plateau fracture patients were treated with 3D surgical planning, including patient-specific drilling guides applied to standard off-the-shelf plates. A postoperative CT scan was obtained to assess whether the screw directions, screw lengths, and plate position were performed according the preoperative planning. Quality of the fracture reduction was assessed by measuring residual intra-articular incongruence (maximum gap and step-off) and compared to a historical matched control group. A total of 15 patients were treated with 3D surgical planning in which 83 screws were placed by using drilling guides. The median deviation of the achieved screw trajectory from the planned trajectory was 3.4° (interquartile range (IQR) 2.5 to 5.4) and the difference in entry points (i.e. plate position) was 3.0 mm (IQR 2.0 to 5.5) compared to the 3D preoperative planning. The length of 72 screws (86.7%) were according to the planning. Compared to the historical cohort, 3D-guided surgery showed an improved surgical reduction in terms of median gap (3.1 vs 4.7 mm; p = 0.126) and step-off (2.9 vs 4.0 mm; p = 0.026). The use of 3D surgical planning including drilling guides was feasible, and facilitated accurate screw directions, screw lengths, and plate positioning. Moreover, the personalized approach improved fracture reduction as compared to a historical cohort.

Four-dimensional treatment planning strategies for dynamic tumor tracking.

Dynamic tumor tracking (DTT) is a motion management technique where the radiation beam follows a moving tumor in real time. Not modelling DTT beam motion in the treatment planning system leaves an organ at risk (OAR) vulnerable to exceeding its dose limit. This work investigates two planning strategies for DTT plans, the "Boolean OAR Method" and the "Aperture Sorting Method," to determine if they can successfully spare an OAR while maintaining sufficient target coverage. A step-and-shoot intensity modulated radiation therapy (sIMRT) treatment plan was re-optimized for 10 previously treated liver stereotactic ablative radiotherapy patients who each had one OAR very close to the target. Two planning strategies were investigated to determine which is more effective at sparing an OAR while maintaining target coverage: (1) the "Boolean OAR Method" created a union of an OAR's contours from two breathing phases (exhale and inhale) on the exhale phase (the planning CT) and protected this combined OAR during plan optimization, (2) the "Aperture Sorting Method" assigned apertures to the breathing phase where they contributed the least to an OAR's maximum dose. All 10 OARs exceeded their dose constraints on the original plan four-dimensional (4D) dose distributions and average target coverage was V100%=91.3%±2.9% (ranging from 85.1% to 94.8%). The "Boolean OAR Method" spared 7/10 OARs, and mean target coverage decreased to V100%=87.1%±3.8% (ranging from 80.7% to 93.7%). The "Aperture Sorting Method" spared 9/10 OARs and the mean target coverage remained high at V100%=91.7%±2.8% (ranging from 84.9% to 94.5%). 4D planning strategies are simple to implement and can improve OAR sparing during DTT treatments. The "Boolean OAR Method" improved sparing of OARs but target coverage was reduced. The "Aperture Sorting Method" further improved sparing of OARs and maintained target coverage.