Preoperative Rehearsal Research Articles

Three-dimensional printing for preoperative rehearsal and intraoperative navigation during laparoscopic rectal cancer surgery with left colic artery preservation

Three-dimensional printing for preoperative rehearsal and intraoperative navigation during laparoscopic rectal cancer surgery with left colic artery preservation

The Integration of 3D Virtual Reality and 3D Printing Technology as Innovative Approaches to Preoperative Planning in Neuro-Oncology.

Our study explores the integration of three-dimensional (3D) virtual reality (VR) and 3D printing in neurosurgical preoperative planning. Traditionally, surgeons relied on two-dimensional (2D) imaging for complex neuroanatomy analyses, requiring significant mental visualization. Fortunately, nowadays advanced technology enables the creation of detailed 3D models from patient scans, utilizing different software. Afterwards, these models can be experienced through VR systems, offering comprehensive preoperative rehearsal opportunities. Additionally, 3D models can be 3D printed for hands-on training, therefore enhancing surgical preparedness. This technological integration transforms the paradigm of neurosurgical planning, ensuring safer procedures.

Emerging Frontiers in Surgical Training: Progress in 3D Printed Gel Models

With the increasing complexity and difficulty of surgical procedures, there is an urgent need for empirical and high-fidelity surgical teaching tools. Whereas in the past, teaching tools included cadavers and animals, today, with the development of three-dimensional (3D) printing technology, the creation of patient-specific organ models is possible. This technology provides an effective solution for preoperative rehearsal, thus providing surgery residents with a more realistic simulation environment. This study aimed to provide an overview of the use of personalized 3D printing in various types of surgery through a scoping review, outline their bottlenecks, and provide an outlook. Significant advancements have been made in 3D-printed gel organ models for surgical applications. However, future advancements require interdisciplinary collaborations, medical–engineering integration and novel techniques. Addressing challenges in preservation, instrument response, ultrasound performance and mechanical properties is crucial. Enhancing these aspects will improve the capabilities of organ models, benefiting both medical practitioners and patients.

Further Validity Evidence for Patient-Specific Virtual Reality Temporal Bone Surgical Simulation.

Patient-specific virtual reality (VR) simulation of cochlear implant (CI) surgery potentially enables preoperative rehearsal and planning. We aim to gather supporting validity evidence for patient-specific simulation through the analysis of virtual performance and comparison with postoperative imaging. Prospective, multi-institutional study. Pre- and postoperative cone-beam CT scans of CI surgical patients were obtained and processed for patient-specific VR simulation. The virtual performances of five trainees and four attendings were recorded and (1) compared with volumes removed during actual surgery as determined in postoperative imaging, and (2) assessed using the Copenhagen Cochlear Implant Surgery Assessment Tool (CISAT) by two blinded raters. The volumes compared were cortical mastoidectomy, facial recess, and round window (RW) cochleostomy as well as violation of the facial nerve and chorda. Trainees drilled more volume in the cortical mastoidectomy and facial recess, whereas attendings drilled more volume for the RW cochleostomy and made more violations. Except for the cochleostomy, attendings removed volumes closer to that determined in postoperative imaging. Trainees achieved a higher CISAT performance score compared with attendings (22.0 vs. 18.4 points) most likely due to lack of certain visual cues. We found that there were differences in performance of trainees and attendings in patient-specific VR simulation of CI surgery as assessed by raters and in comparison with actual drilled volumes. The presented approach of volume comparison is novel and might be used for further validation of patient-specific VR simulation before clinical implementation for preoperative rehearsal in temporal bone surgery. n/a Laryngoscope, 134:1403-1409, 2024.

Preoperative Rehearsal Sketch for Cerebral Aneurysm Clipping Improves the Accuracy and the Safety of the Surgical Procedure

With advances in endovascular therapy, the number of cerebral aneurysm clippings has been decreasing. However, some patients are indicated for clipping surgeries. In such circumstances, preoperative simulation is important for the safety and educational aspects of the operation. Herein, we introduce a simulation method using the preoperative rehearsal sketch and report its applicability. We compared the preoperative rehearsal sketch with the surgical view for all patients who underwent cerebral aneurysm clipping by neurosurgeons below the seventh grade between April 2019 and September 2022 in our facility. The aneurysm, running of parent and branched arteries, perforators, veins, and clip working were evaluated by senior doctors and scored as follows: correct, 2; partially correct, 1; incorrect, 0; and total score, 12. We retrospectively evaluated the relationship between these scores and postoperative perforator infarctions and, in addition, compared that between simulated and not simulated cases. In the simulated cases, the total scores did not correlate with perforator infarctions, but assessments of the aneurysm, perforators, and clip working affected thetotal score (P= 0.039, 0.014, and 0.049, respectively). Moreover, perforator infarctions were significantly less inthe simulated cases (6.3% vs. 38.5%; P= 0.03). Precise interpretations of preoperative images and considerations of three-dimensional images are imperative to perform safe and accurate surgeries using preoperative simulation. Although perforators are not always detected preoperatively, it is possible to presume in the surgical view using anatomic knowledge. Therefore, drawing the preoperative rehearsal sketch improves the safety of surgical procedure.

The "STARS" study: advanced preoperative rehearsal and intraoperative navigation in neurosurgical oncology.

Neurosurgical 3D visualizers and simulators are innovative devices capable of defining a surgical strategy in advance and possibly making neurosurgery safer by rehearsing the phases of the operation beforehand. The aim of this study is to evaluate Surgical Theater™ (Surgical Theater LLC, Mayfield, OH, USA), a new 3D neurosurgical planning, simulation, and navigation system, and qualitatively assess its use in the operating room. Clinical data were collected from 30 patients harboring various types of brain tumors; Surgical Theater™ was used for the preoperative planning and intraoperative 3D navigation. Preoperative and postoperative questionnaires were completed by first and second operators to get qualitative feedback on the system's functionality. Furthermore, we measured and compared the impact of this technology on surgery duration. Neurosurgeons were overall satisfied when using this rehearsal and navigation tool and found it efficient and easy to use; interestingly, residents considered this device more useful as compared to their more senior colleagues (with significantly higher scores, P<0.05), possibly because of their limited anatomical experience and spatial/surgical rehearsal ability. The length of the surgical procedure was not affected by this technology (P>0.05). Surgical Theater™ system was found to be clinically useful in improving anatomical understanding, surgical planning, and intraoperative navigation, especially for younger and less experienced neurosurgeons.

Anesthetic management of a morbidly obese patient with endometrial cancer during robot-assisted laparoscopic surgery

BackgroundThe number of robot-assisted surgeries being performed has increased in recent years, even in patients with risk factors, such as obesity, owing to advancements in medical technologies. We here report the anesthetic management of a morbidly obese woman who underwent robot-assisted surgery.Case presentationA 44-year-old woman (height, 165 cm; weight, 147 kg; body mass index, 54 kg/m2) was scheduled to undergo robot-assisted laparoscopic hysterectomy for endometrial cancer. Preoperative weight loss and rehearsal of positioning during induction of anesthesia and surgical procedures greatly contributed to the surgical success. Monitoring of oxygen reserve index in combination with SpO2 was useful for appropriate airway and respiratory management. During anesthesia induction, the ramp position using a special commercially available cushion facilitated manual mask ventilation and tracheal intubation. Lung-protective ventilation using a limited tidal volume with moderate PEEP was applied during the robot-assisted surgical procedure.ConclusionWe successfully managed anesthesia without any complications.

Stepwise manipulation of cardiac computed tomography multi-planar reconstruction to mimic transesophageal echocardiography.

Cardiac computed tomography (CT) is increasingly used to plan transcatheter structural heart interventions. However, intraoperative guidance relies on transesophageal echocardiography (TEE) and fluoroscopy. This study sought to develop a stepwise CT multi-planar reconstruction manipulation method to mimic TEE, bridging the gap between preoperative planning and intraoperative guidance tools. This CT manipulation reproduced similar configurations as TEE views in the mid-esophageal left ventricle (LV) views, transgastric LV 2-chamber views for mitral apparatus, and other miscellaneous views. Stepwise cardiac CT manipulation to mimic TEE is the final piece of the puzzle in the mental co-registration of these three crucial imaging modalities. Now, we can predict the TEE images and fluoroscopy projections in a preoperative rehearsal, thus improving the intraoperative accuracy of interventions.

Robotic Surgical Assistant Rehearsal: Combining 3-Dimensional-Printing Technology With Preoperative Stereotactic Planning for Placement of Stereoencephalography Electrodes.

The use of frameless stereotactic robotic technology has rapidly expanded since the Food and Drug Administration's approval of the Robotic Surgical Assistant (ROSA) in 2012. Although the use of the ROSA robot has greatly augmented stereotactic placement of intracerebral stereoelectroencephalography (sEEG) for the purposes of epileptogenic focus identification, the preoperative planning stages remain limited to computer software. To describe the use of a 3-dimensionally (3D)-printed patient model in the preoperative planning of ROSA-assisted depth electrode placement for epilepsy monitoring in a pediatric patient. An anatomically accurate 3D model was created and registered in a preoperative rehearsal session using the ROSA platform. After standard software-based electrode trajectory planning, sEEG electrodes were sequentially placed in the 3D model. Utilization of the 3D-printed model enabled workflow optimization and increased staff familiarity with the logistics of the robotic technology as it relates to depth electrode placement. The rehearsal maneuvers enabled optimization of patient head positioning as well as identification of physical conflicts between 2 electrodes. This permitted revision of trajectory planning in anticipation of the actual case, thereby improving patient safety and decreasing operative time. Use of a 3D-printed patient model enhanced presurgical positioning and trajectory planning in the placement of stereotactic sEEG electrodes for epilepsy monitoring in a pediatric patient. The ROSA rehearsal decreased operative time and increased efficiency of electrode placement.

Robotic Surgical Assistant (ROSA™) Rehearsal: Using 3-Dimensional Printing Technology to Facilitate the Introduction of Stereotactic Robotic Neurosurgical Equipment.

The use of frameless stereotactic robotic technology has rapidly expanded since the Food and Drug Administration's approval of the Robotic Surgical Assistant (ROSA™) in 2012. Although the safety and accuracy of the ROSA platform has been well-established, the introduction of complex robotic technology into an existing surgical practice poses technical and logistical challenges particular to a given institution. To better facilitate the integration of new surgical equipment into the armamentarium of a thriving pediatric neurosurgery practice by describing the use of a three-dimensional (3D)-printed patient model with in situ 3D-printed tumor for presurgical positioning and trajectory optimization in the stereotactic biopsy of a pontine lesion in a pediatric patient. A 3D model was created with an added silicone mock tumor at the anatomical position of the lesion. In a preoperative rehearsal session, the patient model was pinned and registered using the ROSA platform, and a mock biopsy was performed targeting the in Situ silicone tumor. Utilization of the 3D-printed model enabled workflow optimization and increased staff familiarity with the logistics of the robotic technology. Biopsy trajectory successfully reached intralesional tissue on the 3D-printed model. The rehearsal maneuvers decreased operative and intubation time for the patient and improved operative staff familiarity with the robotic setup. Use of a 3D-printed patient model enhanced presurgical positioning and trajectory planning in the biopsy of a difficult to reach pontine lesion in a pediatric patient. The ROSA rehearsal decreased operative time and increased staff familiarity with a new complex surgical equipment.

Application of 3D printing technology to thoracic wall tumor resection and thoracic wall reconstruction.

Thoracic wall tumors can leave large defects in the thoracic wall after tumor resection. Currently, the shape of the materials commonly used for thoracic wall repair, including dacron mesh and titanium alloy mesh, cannot readily conform to the shapes of defect sites. In this study, we aimed to retrospectively review and evaluate the outcomes of applying three-dimensional (3D) printing technology in assisting in thoracic wall tumor resection and thoracic wall construction. Six patients with thoracic wall tumors underwent thin-slice CT scanning. We 3D reconstructed pleural tumors and adjacent structures with Amira software and 3D printed them. Preoperative simulation, surgical rehearsal, and surgical planning were performed, and 3D conformal titanium plates were created based on 3D reconstruction models and sutured to the defect sites of the thoracic wall. We also retrospectively reviewed 10 patients who underwent this surgery with conventional methods. All of the demographic data, clinical data, and laboratory findings (non-normally distributed variables) were compared between these two groups. 3D reconstructions of the tumors and their adjacent structures were successfully performed, and 3D printing physical models and conformal titanium plates were also successfully obtained. The plate afforded accurate matching, less bleeding, fewer postoperative complications, and less pain. This 3D printing technology can aid in preoperative rehearsal, surgical planning, and the manufacturing of 3D implants. The 3D titanium plate has such advantages over traditional implants as having good fit and hardness, improving the surgical accuracy and curative effect, and reducing complications, such as bleeding and pain.

Elements of virtual temporal bone surgery: Manipulandum format may be more important to surgeons than haptic device force capabilities.

BackgroundTemporal bone simulations are critiqued for poor drill‐bone interaction. This project appraises the import of increasing haptic device and manipulandum fidelity on the perceived realism of drilling a virtual temporal bone.Virtual surgical contact forces rely on haptic device fidelity and are transmitted through a manipulandum. With identical software, both device hardware and manipulandum may each contribute to realism. We compare the three degrees of freedom (DOF), 3N Geomagic Touch (3D Systems, SC) to a 6DOF, 5.5N HD2 (Quanser, ON) with the both standard (“HD2–Standard”) and in‐house customized otic drill manipulandum (“HD2–Modified”).MethodsSix otologic surgeons performed three virtual mastoidectomy surgeries on a temporal bone surgical simulator. The HD2 manipulandum was modified for attached otic drill with gravity compensation and requisite mechanical modifications. Surgeons, in random order, performed the dissection with the different hardware platforms.ResultsTwo‐tailed t‐tests demonstrate that for the acoustic properties of each simulation, the HD2–Modified manipulandum was favored (p ≤ 0.0004). For overall similarity of bone, both HD2–Standard (p ≤ 0.05) HD2–Modified (p ≤ 0.03)) were favored over the Geomagic; however they were not appreciably different when directly compared to each other. There was no preference for increasing haptic device fidelity in virtual drill bone interaction.In forced rank, users favored the HD2–Modified in osseus, vibrational and overall realism, as well as being preferred for education and preoperative rehearsal (p ≤ 0.0164).ConclusionIncreasing manipulandum realism was favored. However surprisingly, there was no preference for increased device fidelity, illustrating incremental stiffness had nominal impact. There may be a ceiling to drill bone interaction in virtual haptic simulation.Level of Evidence2b.

Применение 3D-печати в урологии

The purpose of this article is to outline the role and possible applications of 3D printing in urology. At present, this technique provides the opportunity to choose the individual strategy of patient management, to conduct preoperative planning and surgical rehearsal; for medical specialists to reduce the learning curve in mastering modern complex surgical techniques, and for doctors and students to improve understanding of pathological processes in the kidney and the prostate gland.

3D printed mitral valve models: affordable simulation for robotic mitral valve repair.

3D printed mitral valve (MV) models that capture the suture response of real tissue may be utilized as surgical training tools. Leveraging clinical imaging modalities, 3D computerized modelling and 3D printing technology to produce affordable models complements currently available virtual simulators and paves the way for patient- and pathology-specific preoperative rehearsal. We used polyvinyl alcohol, a dissolvable thermoplastic, to 3D print moulds that were casted with liquid platinum-cure silicone yielding flexible, low-cost MV models capable of simulating valvular tissue. Silicone-moulded MV models were fabricated for 2 morphologies: the normal MV and the P2 flail. The moulded valves were plication and suture tested in a laparoscopic trainer box with a da Vinci Si robotic surgical system. One cardiothoracic surgery fellow and 1 attending surgeon qualitatively evaluated the ability of the valves to recapitulate tissue feel through surveys utilizing the 5-point Likert-type scale to grade impressions of the valves. Valves produced with the moulding and casting method maintained anatomical dimensions within 3% of directly 3D printed acrylonitrile butadiene styrene controls for both morphologies. Likert-type scale mean scores corresponded with a realistic material response to sutures (5.0/5), tensile strength that is similar to real MV tissue (5.0/5) and anatomical appearance resembling real MVs (5.0/5), indicating that evaluators 'agreed' that these aspects of the model were appropriate for training. Evaluators 'somewhat agreed' that the overall model durability was appropriate for training (4.0/5) due to the mounting design. Qualitative differences in repair quality were notable between fellow and attending surgeon. 3D computer-aided design, 3D printing and fabrication techniques can be applied to fabricate affordable, high-quality educational models for technical training that are capable of differentiating proficiency levels among users.

V4-01 PATIENT SPECIFIC REHEARSAL USING 3D PRINTING FOR COMPLEX PARTIAL NEPHRECTOMY CASES

You have accessJournal of UrologyImaging/Uroradiology1 Apr 2017V4-01 PATIENT SPECIFIC REHEARSAL USING 3D PRINTING FOR COMPLEX PARTIAL NEPHRECTOMY CASES Jonathan Stone, Rachel Melnyk, Guan Wu, Hani Rashid, Jean Joseph, and Ahmed Ghazi Jonathan StoneJonathan Stone More articles by this author , Rachel MelnykRachel Melnyk More articles by this author , Guan WuGuan Wu More articles by this author , Hani RashidHani Rashid More articles by this author , Jean JosephJean Joseph More articles by this author , and Ahmed GhaziAhmed Ghazi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.900AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The benefits of surgical simulation have been previously demonstrated to enhance technical skills with a downstream effect of improved patient outcomes. However, other methods to utilize simulation technology remain under-explored. One area of simulation that has proven to be difficult is the creation of a high fidelity process that accurately and reproducibly simulates individual anatomy and pathology (i.e. patient specific simulators). Advances in 3-D printing and polymer technology, coupled with software that incorporates imaging data into a computer design, make it possible to develop individualized models from patient imaging data. We present the feasibility of patient-specific preoperative rehearsal using 3D processing & printing in complex partial nephrectomy cases. METHODS Three patients with enhancing renal lesions suspicious for renal malignancy with complex tumor morphology or significant comorbidities were chosen for preoperative simulation and rehearsal. DICOM files of patients C.T. angiography (CTA) were imported into 3D processing software to create virtual models of kidney parenchyma incorporating the tumor, renal vasculature, and pelvicalyceal system. Surgical phantoms were created using 3D printing and polymer hydrogels, for patient-specific surgical rehearsal. For whole task preoperative surgical rehearsal, other relevant anatomical elements (bowel, perinephric fat, solid organs and bony structures) were incorporated into a replicated hemiabdomen. RESULTS All 3 preoperative simulations were completed prior to the live case. Partial nephrectomy was successful in all 3 cases with an average blood loss of 300cc and WIT of 20 minutes. For the first case, preoperative 3D processing and hydrogel kidney aided in assessing the depth of resection of a completely endophytic tumor and predicted violation of the pelvicalyceal system in the live case. In the 2nd case, the preoperative rehearsals ascertained the feasibility of completing partial nephrectomy in a 9 cm upper pole mass. In the final case, the preoperative rehearsals confirmed the feeding vessel and viability of selective ischemia with his existing coagulopathy and nephropathy. CONCLUSIONS This initial trial demonstrates that patient-specific procedural rehearsal is effective for enhancing the performance of surgeons during a complex minimal invasive procedure. This transition from generalized to patient-specific simulation may have the potential to impact patient outcomes by permitting preoperative rehearsal. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e375 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Jonathan Stone More articles by this author Rachel Melnyk More articles by this author Guan Wu More articles by this author Hani Rashid More articles by this author Jean Joseph More articles by this author Ahmed Ghazi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Application of Echocardiographic Three-Dimensional Printed Left Atrial Appendage Model to Guide Transcatheter Left Atrial Appendage Occlusion

This study aimed to determine the feasibility of three dimensional (3D) printed left atrial appendage (LAA) models based on 3D transesophageal echocardiography (3D TEE) data and its application value in the interventional LAA closure. Eighteen patients who had interventional LAA occlusion underwent pre-procedure TEE and cardiac CT. TEE 3D full volume raw data of the LAA were acquired and post-processed to create a 3D model file. Two modes of the LAA model (cardiac chamber model, cardiac wall model) were printed out by 3D printer. The LAA morphologic classification was assessed by 3D printed chamber model and the LAA dimension measurement was performed on 3D printed wall model. Additionally, preoperative rehearsal was performed on the 3D printed cardiac wall models in the cases with complex LAA structure. In all the patients, 3D TEE full volume data of the LAA were successfully reprocessed and printed out as 3D LAA chamber models and 3D LAA wall models. The consistency of LAA morphologic classification judgment based on 3D printed models and cardiac CT was 0.918 (P<0.01).The LAA ostium dimension measured on 3D printed model was greater than 2D TEE (P<0.01) and smaller than X-ray (P=0.02), and the LAA depth was greater than 2D TEE (P<0.01) whereas was not significantly different with X-ray (P=0.54).Based on 3D model morphology, there were 3 complex LAA which were recommended a particular occlusion plan after pre-procedure rehearsal on 3D model. The occlusion success rate was 100%. Echocardiographic 3D printing technique is feasible and have promising value in supporting planning the transcatheter LAA occlusion.

A 3D PRINTING PRACTICE FOR PREOPERATIVE REHEARSAL BASED ON THE ADDITIVE AND SUBTRACTIVE MANUFACTURING

Preoperative rehearsal is very important before the operation, because of its particularity and difficulty, traditional printing can hardly achieve it, and thus a new kind of fixture for the 3D printing of pelvis model is critical. Fixture design in manufacturing system is very important and directly affects the processing quality, production efficiency and manufacturing costs. As a new method of manufacturing, the alternative style of additive and subtractive manufacturing is potential in market prospect. New requirements on the performance and structure of the fixture were put forward due to the high complexity of product surface in alternative manufacturing, as well as the force characteristics of numerical control (NC) processing. In this paper, we propose a novel type of fixture which is capable of completing printing tasks in preoperative rehearsal. An experiment is performed to validate the rationality and universality of the fixture. A 3D printing practical case of pelvis model before pelvic correction surgery is used to demonstrate the effectiveness of the present fixture.

Use of a surgical rehearsal platform and improvement in aneurysm clipping measures: results of a prospective, randomized trial.

OBJECTIVE The field of neurosurgery is constantly undergoing improvements and advances, both in technique and technology. Cerebrovascular neurosurgery is no exception, with endovascular treatments changing the treatment paradigm. Clipping of aneurysms is still necessary, however, and advances are still being made to improve patient outcomes within the microsurgical treatment of aneurysms. Surgical rehearsal platforms are surgical simulators that offer the opportunity to rehearse a procedure prior to entering the operative suite. This study is designed to determine whether use of a surgical rehearsal platform in aneurysm surgery is helpful in decreasing aneurysm dissection time and clip manipulation of the aneurysm. METHODS The authors conducted a blinded, prospective, randomized study comparing key effort and time variables in aneurysm clip ligation surgery with and without preoperative use of the SuRgical Planner (SRP) surgical rehearsal platform. Initially, 40 patients were randomly assigned to either of two groups: one in which surgery was performed after use of the SRP (SRP group) and one in which surgery was performed without use of the SRP (control group). All operations were videotaped. After exclusion of 6 patients from the SRP group and 9 from the control group, a total of 25 surgical cases were analyzed by a reviewer blinded to group assignment. The videos were analyzed for total microsurgical time, number of clips used, and number of clip placement attempts. Means and standard deviations (SDs) were calculated and compared between groups. RESULTS The mean (± SD) amount of operative time per clip used was 920 ± 770 seconds in the SRP group and 1294 ± 678 seconds in the control group (p = 0.05). In addition, the mean values for the number of clip attempts, total operative time, ratio of clip attempts to clips used, and time per clip attempt were all lower in the SRP group, although the between-group differences were not statistically significant. CONCLUSIONS Preoperative rehearsal with SRP increased efficiency and safety in aneurysm microsurgery as demonstrated by the statistically significant improvement in time per clip used. Although the rest of the outcomes did not demonstrate statistically significant between-group differences, the fact that the SRP group showed improvement in mean values for all measures studied suggests that preoperative rehearsal may increase the efficiency and safety of aneurysm microsurgery. Future studies aimed at improving patient outcome and safety during surgical clipping of aneurysms will be needed to keep pace with the quickly advancing endovascular field.

V9-04 ROBOTIC PARTIAL NEPHRECTOMY IN THE SETTING OF IDIOPATHIC IVC OBSTRUCTION: A MULTIDISCIPLINARY APPROACH

using a novel three dimensional (3d) printing and silicone casting technology. METHODS: Using standard preoperative imaging, 3d reconstruction of renal parenchyma and tumor was performed to generate solid models suitable for rapid fabrication. Leveraging a novel prototyping process that utilizes 3d extrusion printing and subsequent polymer casting we generated pre-surgical models out of a silicone-based material. To determine how well these patientspecific models simulated actual operative experience, we compared enucleation times between model and actual tumor using the same robotic platform. For the final model, we performed 3d laser scans of both the enucleated model and tumor comparing their spatial characteristics. All surgical rehearsals were performed prior to the actual procedure. RESULTS: We generated patient-specific pre-surgical models for 3 patients. R.E.N.A.L. nephrometry scoring for the pre-surgical models was 7a, 8p, 8a and tumor sizes were 3.5x3.4x3.5 cm, 4.1x3.8x3.5 cm, and 1.5x1.4x1.4 cm. Time of enucleation was similar between the patient-specific pre-surgical models and the actual surgery (6:24 vs. 5:58, 3:11 vs. 3:43, 4:55 vs. 6:09 mins). For case #3, the surgical model enucleation volume measured 6.4 mm3 and the actual excised specimen 12.8 mm3. A 3d-reconstructed visual overlay demonstrated a high level of coherence in the shape of the excised tumor and allowed measurement of the difference in the volume of excised normal renal parenchyma between the model and the actual patient specimen. CONCLUSIONS: We have developed a patient-specific presurgical simulation for robotic partial nephrectomy. Our model provides accurate representation of enucleation time and volume of resected tissue. This highly reproducible simulation platform has the potential to alter surgical decision-making and allow for preoperative rehearsal in complex cases. Furthermore it may become a valuable tool for resident training.

3D-CT used to determine an optimal combined anteversion angle of femoral neck-acetabulum in total hip arthroplasty for adult hip developmental dysplasia

Objective To investigate how 3D-CT was used to determine an optimal combined an-teversion angle of femoral neck-acetabulum in total hip arthro (THA) for adult developmental dysplasia of the hip(DDH). Methods 3D-CT was used in 21 adult patients(21 hips) with DDH who had been treated by THA from March 2011 to March 2014. They were 5 men and 16 women, 30 to 78 years of age (average, 55.3 years). By the Crowe classification, there were 6 cases of type Ⅱ, 11 cases of type Ⅲ, and 4 cases of type Ⅳ. After all the patients underwent thin slice CT scanning, their primary 2-dimentional data were imported into M3D visual digitization software for 3-dimentional reconstruction. The 3D-CT images were used before each THA to find an optimal combined anteversion angle of femoral neck-acetabulum for the surgery. After surgery, the 3D-CT images were used to evaluate bony coverage of the acetabulum cup and the agreement between the combined anteversion angle of femoral neck-acetabulum determined preoperatively and the postoperative one. Harris scores were used to evaluate the efficacy of THA. Results The 21 patients were followed up for an average of 12.8 months (range, from 3 to 36 months). The Harris scores at the last follow-up revealed 17 excellent cases and 4 good ones. The preoperative Harris scores (46.2±5.3) increased significantly to 86.3±4.3 at the last follow-up (P<0.05). All the patients obtained bony coverage of the acetabulum cup of more than 70% . The agreement between the combined anteversion angle of femoral neck-acetabulum de-termined preoperatively and the postoperative one reached 95% . All the postoperative combined anteversion angles of femoral neck-acetabulum were in a safe range. No anterior dislocation was observed. Conclusions In a preoperative rehearsal of THA, 3D-CT reconstruction can be used to find an optimal combined an-teversion angle of femoral neck-acetabulum which may lead to the best bony coverage, the most initial sta-bility, the best match between the femoral head and the acetabulum, reduced prosthesis dislocation and in-creased prosthesis survival. Key words: Acetabulum; Arthroplasty, replacement, hip; Imaging, three-dimensional