Surgical Osteotomy Research Articles

The effect of osteotomy depth and hinge axis orientation on biplanar surgical accuracy in medial opening-wedge high tibial osteotomy-a deeper understanding by 3D simulations.

Not all surgical osteotomy steps have been properly investigated for their potential impact on surgical accuracy. The main study objective was to investigate the osteotomy parameters that have respectively major and minor impact on coronal and sagittal bony accuracy in medial opening-wedge high tibial osteotomy (MOWHTO). Three tibias from an existing 3D MOWHTO osteotomy database were chronologically selected based on segmentation quality, tibial plateau size and the presence of tibial varus. The study consisted of three parts: (I) translating the hinge axis in the coronal plane and switching the osteotomy starting point (30-40 mm) and depth, (II) the hinge axis was rotated stepwise by 10° to perform five simulations, (III) the hinge axis was rotated in the axial plane stepwise by 10° towards anterolateral to perform four simulations (0°, +10°, +20°, +30°). The medial proximal tibial angle (MPTA) and lateral tibial slope were the primary outcomes. Simulations were performed with 5, 10 and 15 mm gap distraction. In the coronal plane, maximum difference in osteotomy depth was 10 mm which represented an MPTA difference of 0.8°-1.1° in 10 mm gap distraction and 1.2°-2.0° in 15 mm gap distraction. Tibial slope remained unchanged. Rotating the hinge axis in the sagittal plane delivered minor changes on both MPTA (<0.5°) and tibial slope (<1.5°) at 10 mm gap distraction. Per 10° of axial rotation of the hinge axis towards anterolateral, the tibial slope increased by 1.0°-1.3° in 10 mm gap distraction while the MPTA remains nearly unchanged. The study showed that the medio-lateral osteotomy length is the main parameter for obtaining bony accuracy in the coronal plane and maintaining a strict perpendicular axial hinge axis position is crucial in preserving the native tibial slope. Correct axial alignment of the hinge axis can be obtained by creating an equal osteotomy depth of the anterior and posterior tibial cortices in the lateral metaphyseal area.

3D surgical planning method for lower jaw osteotomies applied to facial feminization surgery

Our proposed method uses a three-dimensional (3D) measurement approach that focuses mainly on the lower jaw from basal, lateral, and frontal views applied to the volumetric skull model derived from a computed tomography (CT) of the head. Likewise, we discuss the geometrical features and clinical considerations involved in the 3D biomodeling of the surgical osteotomy. The workflow that allowed this virtual planning to be developed was composed of medical imaging processing software, data extraction software from images, and statistical software that allows the creation and generation of curve-fitting (nonlinear regression) graphs from data. Thirty-two (32) anatomical points were positioned, sixteen (16) measurements were taken, and two-dimensional (2D) sketches in three views (frontal, lateral, and inferior) were generated to overlap in a 3D environment, which informed the cutting of the desired bone segments. Implementing a nonlinear regression curve-fitting on the contours of the original jaws allowed optimal planning of the osteotomy. Desired cutting shapes were extrapolated for the front view by third-order equations, while for the side and bottom views, log-normal distribution curves and second-order polynomial curves were used, respectively. The reduction in the mandibular volume was between 6.55 and 10.27 %, with two of the most important measurements related to vertical reduction in the lateral views and the difference to determine gonion reduction.

Vertical Mouth Opening Requirements for CAD/CAM Fully Guided Implant Surgery: An Analysis of Different Implant Systems.

To determine the vertical space required for implant osteotomy preparation when utilizing a CAD/CAM fully guided surgical template. A total of 14 surgical osteotomy drills (individual and sequential drills) were collected and measured individually using a digital caliper, as well as the total length when the drills were positioned in a surgical handpiece. The height of the surgical guide sleeves and the offset of 14 implant systems in the market were also collected. The vertical dimension of the drills included in this study ranged from 28.2 to 46.3 mm. When these drills were inserted into the handpiece, the total length ranged from 30.0 to 49.5 mm. The height of the surgical guide sleeve and the offset required for the guide had a range of 3.2 to 7.0 mm and 5.0 to 13.5 mm, respectively. This dimension resulted in the total vertical space required for CAD/CAM fully guided surgical templates for each implant system, which ranged from 30.0 to 58.5 mm. Limited mouth opening can pose challenges and limitations in both guided and nonguided dental implant surgery. It can affect the accessibility of surgical implant placement and may result in increased patient discomfort, surgical implant positioning errors, and postoperative complications. Clinicians should determine the patient's mouth opening capabilities during the treatment planning phase prior to deciding on the appropriate implant system to be used and the implant placement technique.

Predicting delayed extubation and transfer to the intensive care unit in children undergoing posterior fusion surgery for scoliosis : Aretrospective observational study.

Delayed extubation and transfer to the intensive care unit (ICU) in children undergoing major scoliosis surgery may increase postoperative complications, prolong hospital stay, and increase medical expenses; however, whether achild will require delayed extubation or transfer to the ICU after scoliosis orthopedic surgery is not fully understood. In this study, we reviewed the risk factors for delayed extubation and transfer to the ICU after scoliosis orthopedic surgery in children. The electronic medical records of pediatric patients (≤ 18years) who underwent posterior spinal fusion surgery between January 2018 and November 2021 were reviewed and analyzed. Patient characteristics (age, sex, body mass index, American Society of Anesthesiologists, ASA, grade, preoperative lung function, and congenital heart disease), preoperative Cobb angle, scoliosis type, correction rate, vertebral fusion segments, pedicle screws, surgical osteotomy, intraoperative bleeding, intraoperative allogeneic transfusion, intraoperative hemoglobin changes, intraoperative mean arterial pressure changes, intraoperative tidal volume (ml/kg predicted body weight), surgical time, postoperative extubation, and transfer to the ICU were collected. The primary outcomes were delayed extubation and transfer to the ICU. Multivariate logistic regression models were used to determine the risk factors for delayed extubation and ICU transfer. Atotal of 246 children who satisfied the inclusion criteria were enrolled in this study, of whom 23(9.3%) had delayed extubation and 81(32.9%) were transferred to the ICU after surgery. High ASA grade (odds ratio [OR] 5.42; 95% confidence interval [CI] 1.49-19.78; p = 0.010), high Cobb angle (OR 1.04; 95% CI 1.02-1.07; p < 0.001), moderate to severe pulmonary dysfunction (OR 10.9; 95% CI 2.00-59.08; p = 0.006) and prolonged surgical time (OR 1.01; 95% CI 1.00-1.03; p = 0.040) were risk factors for delayed extubation. A high Cobb angle (OR 1.02; 95% CI 1.01-1.04; p = 0.004), high intraoperative bleeding volume (OR 1.06; 95% CI 1.03-1.10; p = 0.001), allogeneic transfusion (OR 3.30; 95% CI 1.24-8.83; p = 0.017) and neuromuscular scoliosis (OR 5.38; 95% CI 1.59-18.25; p = 0.007) were risk factors for transfer to the ICU. A high Cobb angle was arisk factor for both delayed extubation and ICU transfer. Age, sex, body mass index, number of vertebral fusion segments, correction rate, and intraoperative tidal volume were not associated with delayed postoperative extubation and ICU transfer. The most common risk factor for delayed extubation and ICU transfer in pediatric patients who underwent posterior spinal fusion was ahigh Cobb angle. Determining risk factors for apoor prognosis may help optimize perioperative respiratory management strategies and planning of postoperative care for children undergoing complicated spinal surgery.

Effect of Orthognathic Surgery On Pulp Blood Flow and Pulp Sensibility: A Prospective Control Trial

IntroductionOrthognathic surgery has the potential to compromise the vitality of the teeth. This paper aims to assess changes in pulp blood flow (PBF) and pulp sensibility (PS) of the anterior dentition following orthognathic surgery and to assess the influence of the proximity of the surgical osteotomy on the PBF and/or PS. MethodsTwenty-six patients undergoing orthognathic surgery (Le Fort I or bilateral sagittal split osteotomy [BSSO]) were compared to sixteen control patients treated by fixed appliances only using Laser Doppler flowmeter (LDF) and thermal testing (CO2 snow). Surgery patients were tested at T1 (presurgery), T2 (4-5 weeks postsurgery), T3 (3 months postsurgery), and T4 (6 months postsurgery). Control patients were tested at T1 (pretreatment), T2 (6 months posttreatment), T3 (12 months posttreatment), and T4 (18 months posttreatment). Differences between the maxilla and mandible were assessed. ResultsNo differences in PBF or PS were recorded in the control group. In the surgery group, both jaws followed the same pattern after surgery, an initial decrease at T2 followed by a gradual recovery to pretreatment PBF levels with no significant difference between T1 versus T4 in both jaws. No difference in PBF was observed between the maxilla and mandible at any testing time interval. Conclusions and Clinical ImplicationsPBF and PS of the anterior dentition was severely affected immediately postsurgery, followed by a gradual increase to full recovery. This pattern of recovery was exhibited in both jaws. A negative sensibility response or discoloration should not be seen as an indication of irreversible ischemic pulp changes. Monitoring for at least 6 months or using LDF as a confirmatory test is required before any irreversible endodontic treatment is to be considered.

Effect of sequential burr passes on minimally invasive akin and first metatarsal dorsiflexion osteotomies

BackgroundMinimally invasive surgical (MIS) osteotomies are increasing as a surgical option for treating midfoot and forefoot conditions. This study aimed to evaluate the impact of each burr pass on the degree of correction, gap size, and alignment in MIS Akin and first metatarsal dorsiflexion osteotomies (DFO). MethodsMIS Akin and first metatarsal DFO were performed on ten cadaveric specimens. Fluoroscopic measurements included the metatarsal dorsiflexion angle (MDA), dorsal cortical length (MDCL), first phalangeal medial cortical length (PCML) and proximal to distal phalangeal articular angle (PDPAA). ResultsThe average decrease in PCML with each burr pass was as follows: 1.53, 1.33, 1.27, 1.23 and 1.13 mm at the 1st to 5th pass, respectively. The MDCL sequentially decreased by 1.80, 1.59, 1.35, 0.75, and 0.60 mm. The MDA consistently decreased, and the PDPAA incrementally became more valgus oriented. ConclusionOn average, a first metatarsal dorsal wedge resection of 4.7 mm and first phalangeal medial wedge resection of 2.9 mm was achieved after 3 and 2 burr passes, respectively. This data may aid surgeons determine the optimal number of burr passes required to achieve the desired patient-specific surgical correction.

Automation in Dentistry with Mechanical Drills and Lasers for Implant Osteotomy: A Narrative-Scoping Review.

The popularity of implants is increasing with the aging population requiring oral-dental rehabilitation. There are several critical steps in the implant workflow, including case selection, implant design, surgical procedure, biological tissue responses, and functional restoration. Among these steps, surgical osteotomy procedures are a crucial determinant of clinical success. This brief review was aimed at outlining the current state of the field in automation-assisted implant surgical osteotomy technologies. A broad search of the literature was performed to identify current literature. The results are outlined in three broad categories: semi-automated static (image-guided) or dynamic (navigation-assisted) systems, and fully-automated robotic systems. As well as the current mechanical rotary approaches, the literature supporting the use of lasers in further refinement of these approaches is reviewed. The advantages and limitations of adopting autonomous technologies in practical clinical dental practices are discussed. In summary, advances in clinical technologies enable improved precision and efficacious clinical outcomes with implant dentistry. Hard-tissue lasers offer further advancements in precision, improved biological responses, and favorable clinical outcomes that require further investigation.

Cutting guides in mandibular tumor ablation: Are we as accurate as we think?

PurposeTumor margin status is critical in local tumor recurrence and is a significant prognostic factor in head and neck cancer survival. With the introduction of computer-assisted surgical planning, one of the main challenges is the accurate positioning of the surgical cutting guide but there is limited evidence of the accuracy of the 3D cutting guides in mimicking virtually planned osteotomy. This study evaluates the accuracy of osteotomy lines produced by 3D-printed cutting guides and assesses the overall accuracy of mandibular reconstruction. Material and MethodsThe pre and postoperative 3D models were aligned using an automated surface registration feature based on the iterative closest point algorithm. The differences in osteotomy line deviation, linear and angle measurements, and 3D volume quantification of the pre and post models were measured. ResultsWe included 14 patients (8 men and 6 women with ages ranging from 13 to 75 years) with a segmental mandibular resection who met all of the inclusion criteria. The smallest defect size was 4.4 cm, the largest defect was 12.2 cm, and the average was 7.30 cm +/- 2.80 cm. The average deviation between virtually planned osteotomy and actual surgical osteotomy was 1.52 +/-1.02 mm. No covariates were associated with increased inaccuracy of the 3D-printed cutting guides. ConclusionThe finding of this study suggests that virtual surgical planning is an unambiguous paradigm shift in the predictability of the surgical plan and achievement of the reconstruction goals. The 3D-printed cutting guides are a very accurate and reliable tool in translating virtual ablation plans to an actual surgical resection margin.

Early outcomes of oblique lateral interbody fusion with posterior fixation versus posterior interbody fusion with fixation for treating adult degenerative scoliosis

ObjectiveTo compare the surgical trauma and outcomes between oblique lateral interbody fusion (OLIF) and posterior fixation and posterior lumbar interbody fusion (PLIF) with fixation for adult degenerative scoliosis (ADS).MethodsWe included ADS patients who underwent OLIF with fixation or PLIF with fixation treatment from June 2020 to December 2022. The preoperative and postoperative spinal pelvic parameters were measured using X-rays. Clinical symptoms were measured using the Oswestry Disability Index and a visual analog scale. We recorded operation time, intraoperative blood loss, blood transfusion, albumin infusion, surgical fixation segment, surgical osteotomy segment, time, and drainage volume.ResultsForty patients with ADS were included: 20 with OLIF with posterior fixation and 20 with PLIF matched for age, sex, pelvic incidence, and Cobb angle with the OLIF group. There were no significant differences in age, gender, BMI, preoperative spinal parameters, or preoperative clinical symptoms between the groups (p > 0.05). There were no statistical differences in postoperative spinal parameters or clinical symptoms (p > 0.05). Patients in the OLIF group had less intraoperative blood loss (p < 0.01) and fewer intraoperative blood transfusions (p < 0.001) than the posterior surgery group. The number of fixed segments was fewer (p < 0.01), and there were fewer total osteotomy segments (p < 0.001).ConclusionOLIF with posterior fixation surgery can achieve the same corrective effect and efficacy as a posterior internal fusion with fixation surgery for treating ADS. OLIF with posterior fixation surgery causes less trauma and reduces the number of fixation segments.

Virtual-Fixture-Based Osteotomy Shared Control: A Framework for Human-Robot Shared Surgical Osteotomy Manipulation

Virtual-Fixture-Based Osteotomy Shared Control: A Framework for Human-Robot Shared Surgical Osteotomy Manipulation

Effectiveness of individualized 3D titanium-printed Orthognathic osteotomy guides and custom plates

BackgroundComputer-aided design/manufacturing (CAD/CAM) technology was developed to improve surgical accuracy and minimize errors in surgical planning and orthognathic surgery. However, its accurate implementation during surgery remains a challenge. Hence, we compared the accuracy and stability of conventional orthognathic surgery and the novel modalities, such as virtual simulation and three-dimensional (3D) titanium-printed customized surgical osteotomy guides and plates.MethodsThis prospective study included 12 patients who were willing to undergo orthognathic surgery. The study group consisted of patients who underwent orthognathic two-jaw surgery using 3D-printed patient-specific plates processed by selective laser melting and an osteotomy guide; orthognathic surgery was also performed by the surgeon directly bending the ready-made plate in the control group. Based on the preoperative computed tomography images and intraoral 3D scan data, a 3D virtual surgery plan was implemented in the virtual simulation module, and the surgical guide and bone fixation plate were fabricated. The accuracy and stability were evaluated by comparing the results of the preoperative virtual simulation (T0) to those at 7 days (T1) and 6 months (T2) post-surgery.ResultThe accuracy (ΔT1‒T0) and stability (ΔT2‒T1) measurements, using 11 anatomical references, both demonstrated more accurate results in the study group. The mean difference of accuracy for the study group (0.485 ± 0.280 mm) was significantly lower than in the control group (1.213 ± 0.716 mm) (P < 0.01). The mean operation time (6.83 ± 0.72 h) in the control group was longer than in the study group (5.76 ± 0.43 h) (P < 0.05).ConclusionThis prospective clinical study demonstrated the accuracy, stability, and effectiveness of using virtual preoperative simulation and patient-customized osteotomy guides and plates for orthognathic surgery.

Evaluation of trabecular changes following advancement genioplasty combined with or without bilateral sagittal split osteotomy by fractal analysis: a retrospective cohort study

BackgroundIt is aimed to investigate whether there was a difference in radiographic changes in the operational areas between genioplasty alone and genioplasty combined with mandibular advancement and to evaluate the fractal dimension (FD) to assess trabecular changes after genioplasty surgery.MethodsPreoperative-(T0) and postoperative-(T1) panoramic radiographs of 26 patients without any complications who underwent genioplasty combined with bilateral sagittal osteotomy and mandibular advancement or genioplasty alone were selected. In the panoramic radiographs of both groups, the genial segment, mandibular angulus, and surgical osteotomy line were examined using FD. The box-counting method was used for FD evaluation.ResultsIt was determined that FD values before and after treatment were similar in both groups for all regions where measurements were made. After surgery, the FD values of the middle region of the genial segment were found to be significantly lower than the other regions. At T1, the FD values at the osteotomy area were found to be significantly higher than those in the middle region of the genial segment.ConclusionTrabecular structure does not differ in patients undergoing genioplasty alone or in combination with mandibular advancement osteotomy. The middle region of the genial segment heals later than other regions.

Application of Orthognathic Surgery Principles and Techniques in the Management of Craniomaxillofacial Trauma.

Posttraumatic secondary deformities of facial skeleton may occur because of nonmanagement or ill management of primary injuries, whereas some unexpectedly occur even after dedicated management attempts. Orthognathic surgery (OGS) principles and techniques can be used as an efficient tool to correct posttraumatic craniomaxillofacial deformities or skeletal developmental deformities during trauma management. The aims of this study were to describe the different types of posttraumatic secondary deformity and address how to use the principles of orthognathic techniques to correct them. Patients with orthognathic surgical osteotomies during primary or secondary management of facial trauma (referred to as trauma-OGS) during the period of 2010 to 2018 were retrospectively reviewed. Variables pertaining to patients and surgery were collected, including trauma diagnosis, etiology, duration between trauma/primary surgery and secondary presentation, suggested reason for secondary deformity, intervention undertaken to address, and the surgical outcome. Twenty-seven patients were eligible and extensively reviewed. Etiological categorization of trauma-OGS could be done into posttraumatic deformities (18) and developmental deformities (9). The former group was further categorized as OGS done as primary procedure (8) that included immobile Le Fort fractures and delayed initial treatment, and OGS done as secondary procedure (10) that included complex fractures and condylar fractures. The developmental deformity group was categorized into OGS done simultaneously during trauma management (5) or done as a secondary procedure after trauma management (4). Application of principles and techniques of OGS in indicated primary or secondary management of facial trauma patients should always be considered. The categorization of scenarios presented in this article relating facial trauma and OGS may further help to understand the application.

Complex case treatment: Is there a limit for surgery-first approach?

Are there any limits for Surgery-first approach? the article strives to identify the tenets of effective management of complex cases, such as facial asymmetry, with surgery-first approach. The main purpose of the article is in attempting to itemize prerequisites or determining factors, through various degrees of facial asymmetry severity, for the successful management of facial asymmetry cases. The key factors such as (1) assessment of chin deviation, (2) quantification or discernment of transverse occlusal plane canting, (3) spatial orientation evaluation of differential anterior and posterior region transverse occlusal canting, and (4) contemplations of six degrees of freedom (6DoF) (translation movements combined with rotation axis - pitch, roll and yaw) are evaluated. Furthermore, dental alignment, severity of mandibular and maxillary occlusal (anterior and posterior) plane canting, critical cephalometric parameters, such as, incisor mandibular plane angle, and other vital sub- components of facial asymmetry are analysed, in detail. Subsequently, these are coherently synchronized with the maxillomandibular complex (MMC) rotation surgery during planning for the successful execution of facial asymmetry correction. Additionally, the article describes the (1) usage of orthodontic arch wires, (2) selection criteria of specific surgical osteotomies, and (3) coordination of maxillary and mandibular dentition to establish a transitional or treatable malocclusion. In conclusion, a thorough evaluation of the determining factors, as described in the article, for the correction of facial asymmetry with surgery-first, aid in categorising facial asymmetry cases that require minimal pre-surgical orthodontics or without pre-surgical orthodontic treatment, thereby defining the limits of surgery-first.

Translated article] Surgical treatment at adult acquired flatfoot stage IIB: Spring ligament repair

Background and aimsThe spring ligament has paramount role in supporting the arches and its fail causes the collapse of the medial longitudinal arc, inducing adult acquired flatfoot deformity. Our aim was to analyze the clinical and radiological outcomes of spring ligament repair and titanium wedges integration used in surgical osteotomies. Material and methodsWe performed a retrospective study of 23 cases with middle ages of 63, diagnosed with adult acquired flatfoot deformity stage IIB in RAM classification after ortho-prosthetic treatment failure, assessing the functional outcomes using the American Orthopedic Foot and Ankle Society scale and the radiological outcomes studying angles variation (talonavicular uncoverage, talo-first metatarsal angle and Meary axis). ResultsThe mean preoperative American Orthopedic Foot and Ankle Society score of the sample was 52±10 and the postoperative 88±6 (p<0.05). The radiological outcomes showed a statistically significant improvement. ConclusionSpring ligament repair associated to bone reconstruction offers large functional and radiological outcomes to adult acquired flatfoot deformity stage IIB treatment. Titanium wedges present an excellent bone integration.

Tratamiento quirúrgico del pie plano valgo adquirido del adulto en estadio IIB: papel de la reparación del «spring ligament»

Background and aimsThe spring ligament has paramount role in supporting the arches and its fail causes the collapse of the medial longitudinal arc, inducing adult acquired flatfoot deformity. Our aim was to analyze the clinical and radiological outcomes of spring ligament repair and titanium wedges integration used in surgical osteotomies. Material and methodsWe performed a retrospective study of 23 cases with middle ages of 63, diagnosed with adult acquired flatfoot deformity stage IIB in RAM classification after ortho-prosthetic treatment failure, assessing the functional outcomes using the American Orthopedic Foot and Ankle Society scale and the radiological outcomes studying angles variation (talonavicular uncoverage, talo-first metatarsal angle and Meary axis). ResultsThe mean preoperative American Orthopedic Foot and Ankle Society score of the sample was 52±10 and the postoperative 88±6 (p<0.05). The radiological outcomes showed a statistically significant improvement. ConclusionSpring ligament repair associated to bone reconstruction offers large functional and radiological outcomes to adult acquired flatfoot deformity stage IIB treatment. Titanium wedges present an excellent bone integration.

Erratum: Combined Surgical Dislocation and Periacetabular Osteotomy for Complex Residual Legg-Calvé-Perthes Deformities.

Erratum: Combined Surgical Dislocation and Periacetabular Osteotomy for Complex Residual Legg-Calvé-Perthes Deformities.

A Novel Method for Preoperative Positioning of Total Ankle Replacement Using 3D Digital Model.

ObjectiveTo establish a digital model of the ankle joint through 3D imaging technology and explore the preoperative placement of ankle replacement prostheses.MethodsComputed tomography images of intact ankle joints from 54 cases in the outpatient and inpatient departments of our hospital were collected; according to the INBONE® total ankle system surgery process, the surgery model and surgical osteotomy were finished using MIMICS based on computer simulation method. The shortest distance was measured between the center point and the anterior, posterior, medial, and lateral, respectively, to ensure the precise position of the ankle replacement prosthesis by digital simulation surgery. The relationship between the two variables was analyzed by bivariate correlation analysis.ResultsThe dataset of this study included 48 cases of the sub‐data set (26 males and 22 females) and included 27 cases of left ankle and 21 cases of right ankle. The average medial malleolar angle was 18.67°± 2.87°, the average amount of bone resection was 12.13 ± 1.86 cm3, the mid‐anterior distance was 1.72 ± 0.19 cm, the mid‐posterior distance was 2.00 ± 0.19 cm, the ratio of mid‐anterior to mid‐posterior was 0.87, the mid‐medial distance was 1.26 ± 0.17 cm, the mid‐lateral distance was 1.19 ± 0.16 cm, and the ratio of mid‐medial to mid‐lateral was 1.06. After osteotomy, the anteroposterior diameter was 3.73 ± 0.32 cm, the transverse diameter was 2.46 ± 0.27 cm, and the ratio of anteroposterior diameter to transverse diameter was 1.53. In the bottom view, the shape after osteotomy is rectangular. The mid‐anterior distance was strongly negatively correlated with age, the mid‐anterior distance and the amount of bone resection, the mid‐medial distance and the amount of bone resection, the mid‐lateral distance and the amount of bone resection, the mid‐lateral distance and the anteroposterior diameter, the anteroposterior diameter and the transverse diameter were all strongly positively correlated.ConclusionThe projection point of the lower tibia centerline on the tibial horizontal osteotomy surface is located at a position slightly anterior to the midpoint of the transverse diameter after ankle arthroplasty. The rational positioning of the total ankle replacement is located at both a position slightly anterior to the midpoint of the transverse diameter and midpoint of the anteroposterior diameter, which can be used as a reference method before total ankle arthroplasty surgery.

A level set approach to high fidelity interactive bone shaving for virtual training of surgical osteotomies.

Interactive multimodal surgical simulators are powerful tools that allow efficient and objective assessment of surgical skills. Bilateral Sagittal Split Osteotomy (BSSO) requires precise cutting of the mandible with a motorized saw that cannot afford a high margin of error. Surgeons rely on visual and haptic cues that are hard to train for through existing curricula without training directly on patients. In this paper, we present a new algorithm to achieve low-cost, precise sawing of the bone that is capable of providing realistic force feedback to the user at haptic rates (~1000Hz). Our method is centered around treating the bone surface as a level set that is evolved at interactive rates upon user's interaction with the virtual saw. The movement of the virtual saw itself is governed by a rigid body solver which is attached to the pose (6 degrees of freedom) of the haptic device via a mass-spring-damper which also supplies haptic force feedback. Our method allows parameterization of the erosion rate, saw speed, and bone density thus making it suitable to any material shaving application including dentistry (e.g., tooth milling) and a variety of surgical osteotomies.

Use of Dental Impression Silicone to Fabricate Simple Surgical Guides in Mandibular Reconstruction∗.

Several recent reports have described the development and use of three-dimensional (3D) printed surgical osteotomy guides. However, these methods: are usually costly. Here, we introduce a novel method of manufacturing surgical guides built from inexpensive, easy-to-use, and sterilizable dental impression silicone. Mandibular and fibular models were prepared using a 3D printer for 10 patients undergoing free fibula flap transfer after mandibular resection. During preoperative simulation surgery, Protesil labor, a dental silicone, was molded to the same size as the fibular models to act as surgical guides. The authors compared pre- and post-operative bone angles and bone lengths for all cases using simulation surgery models and postoperative 3D computed tomography. Mean bone angle difference was 2.6° and mean bone length difference was 1.7 mm. Cost of the dental silicone was approximately US$5/patient. In our series this method allowed the surgeon to perform an accurate osteotomy, inexpensively and time-efficiently.