Osteotomy Plane Research Articles

Biomechanical model of minimally invasive hallux valgus surgery

Hallux valgus is a common foot deformity characterized by outward tilting and twisting of the big toe, often accompanied by a medial prominence at the base. Minimally invasive surgical techniques are widely utilized for treating metatarsus adductus due to their advantages of smaller incisions, faster recovery, and early weight-bearing. However, due to individual variations and limited sample size, the biomechanical effects of different Kirschner wire fixation methods and the underlying mechanisms of postoperative metatarsalgia remain unclear. In this study, a finite element method was employed to develop a biomechanical model of metatarsus adductus. The influence of various Kirschner wire entry points and angles on foot loading characteristics was investigated. Six different Kirschner wire fixation models, including two entry methods (along the adjacent fracture line and proximal-biased entry at the midshaft of the metatarsal) with different entry angles, were analyzed. Mechanical parameters such as metatarsal stress distribution, plantar pressure distribution, and displacement of the first metatarsal osteotomy plane were assessed. This research aims to enhance understanding of minimally invasive surgery and its fixation methods for metatarsus adductus. By providing scientific support and reliable evidence, it seeks to contribute to the development of minimally invasive surgical techniques and the improvement of clinical practice in metatarsus adductus surgery. Ultimately, the goal is to reduce complications, increase surgical success rates, and enhance patient satisfaction.

Reliabilities of three methods used to evaluate computer-assisted mandibular reconstructions using free fibula flaps

ObjectiveThis study compared the reliabilities of three different methods used to calculate surgical deviations after mandibular reconstructions using free fibular flaps. Study designThis retrospective study involved 35 patients who underwent computer-assisted mandibular reconstructions using free fibula flaps. The deviations between the virtual surgical plans and the postoperative results were independently analyzed by two researchers using three distinct methods. In Method A, the fibular axis, the center of gravity, and the osteotomy plane served as landmarks when measuring surgical deviations. In Methods B and C, manually designated points were used to measure errors in the fibular length and intersegmental angle. The primary outcome variables were the intraclass correlation coefficients (ICCs) that revealed the inter-rater agreements for all three methods. ResultsThe use of Method A was associated with good agreement in terms of the fibular length deviation (ICC = 0.765) and intersegmental angle (ICC = 0.897); both were higher than those afforded by Methods B (ICC = 0.158 and 0.108) and C (ICC = 0.406 and 0.463). The measurements of the fibular transfer osteotomy deviation (ICC = 0.888), linear deviation (0.926), and angular deviation (0.958) were very reliable. ConclusionsMethod A afforded the highest reliability in clinical practice when evaluating surgical deviations after mandibular reconstruction using fibular flaps.

Chiba osteotomy (Tibial condylar valgus osteotomy) for a large tibial varus deformity: Technical note

Chiba osteotomy is an effective technique for advanced knee osteoarthritis (KOA). The principle of the osteotomy is to correct both varus deformity and intra-articular joint congruity through an L-shaped osteotomy from the medial tibial condyle to the lateral intercondylar eminence. Previous studies have demonstrated that Chiba osteotomy is an effective method for alignment correction surgery for severe knee osteoarthritis. However, these reports slightly differ from the original concept of Chiba osteotomy. This report describes the pre-operative planning and surgical technique of Chiba osteotomy for patients with large tibial varus deformity, focusing on the management of early knee osteoarthritis following conditions such as post-traumatic Blount disease and “Pagoda” like proximal tibia varus deformities, as originally described. Level of evidenceIV

Use of Perpendicular Plate of Ethmoid Split Technique in Rhinoplasty and Septoplasty.

In recent years, the perpendicular plate of ethmoid (PPE) has become a prominent choice for bone-grafting materials. This study introduces the PPE split technique for efficient removal of the bony septum or the harvesting of partial PPE for septal batten grafts in rhinoplasty and septoplasty, particularly suited for cases with thick PPE. Herein, this technique was employed to minimize septal defects and prevent complications while achieving harvested bony grafts of the desired effective thickness. In this retrospective study, 36 patients underwent surgery using the PPE split technique (22 septoplasties and 14 rhinoplasties). The procedure involved detaching the PPE from the septal cartilage and performing a vertical plane osteotomy with a number 10 scalpel blade to remove bony spurs or prepare batten grafts. Paranasal sinus CT revealed that the average anteroinferior PPE thickness was 3.46 mm. This technique was used for both bony batten graft harvesting (26 cases) and bony spur removal, and septum reshaping (10 cases). Successful PPE harvesting was achieved in all cases except for three, which experienced graft breakage. This study demonstrates the viability and effectiveness of the PPE split technique as a supplementary maneuver in septoplasty and rhinoplasty procedures. Its diverse applications include reshaping, correcting deviated septum, harvesting bony batten grafts, and providing support for an aesthetically pleasing nasal profile.

Identifying Lower Extremity Deformities in the Coronal Plane: Lessons From Remote Learning During the COVID-19 Pandemic.

Introduction During the COVID-19 pandemic, the AO Foundation, an orthopedic education organization, had to transition its live education programs to an online format. Skills that were previously evaluated and corrected in person by educators were now assessed through online lectures and discussion groups. Our goal was to evaluate an online course designed to teach the skill of "leg length and coronal deformity measurement" and to assess participants' ability to demonstrate this skill using online software. Methods An IRB-approved study was conducted during an online osteotomy course. A total of 176 participants were instructed on how to measure length and angulation through the course lectures and planning tutorials. The Bonesetter App (Detroit Bonesetter, Detroit, Michigan, USA) was used as the digital planning tool. Participants analyzed four cases of coronal deformity using long-leg standing radiographs. They were required to identify any deformities present, specify the type of deformity, and determine whether it affected the femur, tibia, or joint. Additionally, participants needed to calculate the deformity as part of the osteotomy planning process. Their measurements and drawings were saved and subsequently evaluated by two independent observers. Results Out of 176 online participants, 76% (315 out of 417) correctly completed the four exercises. The most frequent errors occurred in measuring total deformity and joint deformity. The average standard deviation of length measurements was ±0.29 cm (based on 244 measurements), while for angular measurements, it was ±0.71 degrees (based on 688 measurements). The intraclass correlation coefficient was greater than 0.96. Conclusions The online course effectively taught coronal deformity measurement, although participants struggled most with measuring joint angles and total deformity. Future courses should provide more detailed explanations for these measurements.

Robot-Assisted Augmented Reality (AR)-Guided Surgical Navigation for Periacetabular Osteotomy.

Periacetabular osteotomy (PAO) is an effective approach for the surgical treatment of developmental dysplasia of the hip (DDH). However, due to the complex anatomical structure around the hip joint and the limited field of view (FoV) during the surgery, it is challenging for surgeons to perform a PAO surgery. To solve this challenge, we propose a robot-assisted, augmented reality (AR)-guided surgical navigation system for PAO. The system mainly consists of a robot arm, an optical tracker, and a Microsoft HoloLens 2 headset, which is a state-of-the-art (SOTA) optical see-through (OST) head-mounted display (HMD). For AR guidance, we propose an optical marker-based AR registration method to estimate a transformation from the optical tracker coordinate system (COS) to the virtual space COS such that the virtual models can be superimposed on the corresponding physical counterparts. Furthermore, to guide the osteotomy, the developed system automatically aligns a bone saw with osteotomy planes planned in preoperative images. Then, it provides surgeons with not only virtual constraints to restrict movement of the bone saw but also AR guidance for visual feedback without sight diversion, leading to higher surgical accuracy and improved surgical safety. Comprehensive experiments were conducted to evaluate both the AR registration accuracy and osteotomy accuracy of the developed navigation system. The proposed AR registration method achieved an average mean absolute distance error (mADE) of 1.96 ± 0.43 mm. The robotic system achieved an average center translation error of 0.96 ± 0.23 mm, an average maximum distance of 1.31 ± 0.20 mm, and an average angular deviation of 3.77 ± 0.85°. Experimental results demonstrated both the AR registration accuracy and the osteotomy accuracy of the developed system.

Poster 273: Three-Dimensional Imaging Compared to Conventional Radiographs for Corrective Osteotomy Planning: An Advanced Imaging Analysis

Poster 273: Three-Dimensional Imaging Compared to Conventional Radiographs for Corrective Osteotomy Planning: An Advanced Imaging Analysis

Evaluation of the resection plane three-dimensional positional accuracy using a resection guide directional guidance slot; a randomized clinical trial

AimThe study was performed to compare the mandibular resection guide with a directional guidance slot with the conventional guide regarding three-dimensional positional accuracy.Materials and methodsTwenty-six patients with lateral segmental mandibular defects were selected, and randomly allocated into two groups. All defects were managed with preoperative virtual surgical planning. Resection in the test group was conducted using a resection guide with a directional guidance slot, while a conventional resection guide design was utilized in the control group. The linear and angular deviation of the osteotomy planes was analyzed for both groups, along with the accuracy of the insertion of the reconstruction bone block in the resected defect. Data were documented, absolute deviation was calculated, statistical analysis was performed and significance was set at the 5% level.ResultsThe cases conducted with a directional guidance templet reported a statistically significant difference when compared to the conventional edge-cutting guide regarding the linear and angular spatial osteotomy plane position (P < 0.001). The defect span analysis reported excellent levels of agreement in both groups (ICC = 1.00, ICC = 0.995), however, the difference between the groups was statistically significant (P < 0.001).ConclusionThe study demonstrated the enhanced positional accuracy of the resection plane and reconstruction block placement when a directional slot is incorporated in the computer-generated resection guide.

Evaluation of the Dimensional Accuracy of Robot-Guided Laser Osteotomy in Reconstruction with Patient-Specific Implants-An Accuracy Study of Digital High-Tech Procedures.

Background/Objective: With the rapid advancement in surgical technologies, new workflows for mandibular reconstruction are constantly being evaluated. Cutting guides are extensively employed for defining osteotomy planes but are prone to errors during fabrication and positioning. A virtually defined osteotomy plane and drilling holes in robotic surgery minimize potential sources of error and yield highly accurate outcomes. Methods: Ten mandibular replicas were evaluated after cutting-guided saw osteotomy and robot-guided laser osteotomy following reconstruction with patient-specific implants. The descriptive data analysis summarizes the mean, standard deviation (SD), median, minimum, maximum, and root mean square (RMS) values of the surface comparison for 3D printed models regarding trueness and precision. Results: The saw group had a median trueness RMS value of 2.0 mm (SD ± 1.7) and a precision of 1.6 mm (SD ± 1.4). The laser group had a median trueness RMS value of 1.2 mm (SD ± 1.1) and an equal precision of 1.6 mm (SD ± 1.4). These results indicate that robot-guided laser osteotomies have a comparable accuracy to cutting-guided saw osteotomies, even though there was a lack of statistical significance. Conclusions: Despite the limited sample size, this digital high-tech procedure has been shown to be potentially equivalent to the conventional osteotomy method. Robotic surgery and laser osteotomy offers enormous advantages, as they enable the seamless integration of precise virtual preoperative planning and exact execution in the human body, eliminating the need for surgical guides in the future.

A novel “Precision technique” for preoperative planning of posterior tibial slope correction osteotomy

A novel “Precision technique” for preoperative planning of posterior tibial slope correction osteotomy

Morphometric analysis of proximal femur in Indian population and its implications in Total Hip Arthroplasty

Geometric understanding of the proximal end of femur is significant for functional bipedal erect posture and in pre-operative planning of osteotomy as well as the design and development of implants for THA. Moreover, the anthropological parameters of any bone are determined by genetic and environmental factors such as age, race, gender and lifestyle and this leads to racial variations in the morphological parameters of proximal end of femur owing to lifestyle, physique, applied force and their distribution in India population.The current study was designed to study and compare the morphology of proximal end of femur in Indian population and was conducted on 94 dry human cadaveric bones of unknown age and sex to determine the morphology of the proximal end of femur. We observed the Femur Length as 426.6 ± 15.82 mm, Femur Neck Length as 3.455 ± 0.378 mm and Neck Shaft Angle as 125.27 ± 2.54° amongst other parameters.The findings also revealed significant variations in the morphological parameters among different populations, emphasizing the importance of considering racial diversity in the design and selection of implants for THA for improving the success and longevity of hip arthroplasty procedures.

Osteotomy around the painful degenerative varus knee has broader indications than conventionally described but must follow a strict planning process: ESSKA Formal Consensus Part I.

The European consensus was designed with the objective of combining science and expertise to produce recommendations that would educate and provide guidance in the treatment of the painful degenerative varus knee. Part I focused on indications and planning. Ninety-four orthopaedic surgeons from 24 European countries were involved in the consensus, which focused on the most common indications for osteotomy around the knee. The consensus was performed according to an established ESSKA methodology. The questions and recommendations made were initially designed by the consensus steering group. And 'best possible' answers were provided based upon the scientific evidence available and the experience of the experts. The statements produced were further evaluated by ratings and peer review groups before a final consensus was reached. There is no reliable evidence to exclude patients based on age, gender or body weight. An individualised approach is advised; however, cessation of smoking is recommended. The same applies to lesser degrees of patellofemoral and lateral compartment arthritis, which may be accepted in certain situations. Good-quality limb alignment and knee radiographs are a mandatory requirement for planning of osteotomies, and Paley's angles and normal ranges are recommended when undertaking deformity analysis. Emphasis is placed upon the correct level at which correction of varus malalignment is performed, which may involve double-level osteotomy. This includes recognition of the importance of individual bone morphology and the maintenance of a physiologically appropriate joint line orientation. The indications of knee osteotomies for painful degenerative varus knees are broad. Part I of the consensus highlights the versatility of the procedure to address multiple scenarios with bespoke planning for each case. Deformity analysis is mandatory for defining the bone morphology, the site of the deformity and planning the correct procedure. Level II, consensus.

A finite element model of human hindfoot and its application in supramalleolar osteotomy

BackgroundThe majority of the ankle osteoarthritis cases are posttraumatic and affect younger patients with a longer projected life span. Hence, joint-preserving surgery, such as supramalleolar osteotomy becomes popular among young patients, especially those with asymmetric arthritis due to alignment deformities. However, there is a lack of biomechanical studies on postoperative evaluation of stress at ankle joints. We aimed to construct a verifiable finite element model of the human hindfoot, and to explore the effect of different osteotomy parameters on the treatment of varus ankle arthritis. MethodsThe bones of the hindfoot are reconstructed using normal CT tomography data from healthy volunteers, while the cartilages and ligaments are determined from the literature. The finite element calculation results are compared with the weight-bearing CT (WBCT) data to validate the model. By setting different model parameters, such as the osteotomy height (L) and the osteotomy distraction distance (h), the effects of different surgical parameters on the contact stress of the ankle joint surface are compared. FindingsThe alignment and the deformation of hindfoot bones as determined by the finite element analysis aligns closely with the data obtained from WBCT. The maximum contact stress of the ankle joint surface calculated by this model increases with the increase of the varus angle. The maximum contact stresses as a function of the L and h of the ankle joint surface are determined. InterpretationThe relationship between surgical parameters and stress at the ankle joint in our study could further help guiding the planning of the supramalleolar osteotomy according to the varus/valgus alignment of the patients.

3D pre-operative planning and patient-specific guides for re-directional peri-acetabular osteotomy in children and adolescents

Surgical procedures to correct hip dysplasia associated with subluxation or dislocation of the femoral head are complex. The 3D geometric abnormalities of the acetabulum and proximal femur vary across patients. We, therefore, suggest a patient-specific surgical treatment involving computer-assisted 3D planning of the peri-acetabular osteotomies, taking into account the femoral head position; 3D printing of patient-specific guides for the cuts, repositioning, and fixation; and intra-operative application of the simulated displacements with their fixation. Level of evidenceIV.

Comparison of two versus three-screw fixation for biplanar chevron medial malleolar osteotomy.

This study was designed to compare the clinical outcomes and complications of using two versus three screws to fix the biplanar chevron medial malleolar osteotomy (MMO). A retrospective review was conducted on 43 patients (46 ankles) who underwent biplanar chevron MMO to treat talus osteochondral lesions. Of these, MMO was fixed with two parallel screws placed perpendicular to the osteotomy plane in 16 ankles, while in the remaining 30 ankles, MMO was secured with two parallel screws plus an additional third screw inserted parallel to the tibial plafond. Patients were divided into two groups based on the fixation method and clinical outcomes, union and malunion rates, and complications were compared. Demographic and clinical characteristics such as age (p: 0.411), gender distribution (p: 0.119), affected side (p: 0.126), lesion grades (p: 0.056), and lesion sizes (p: 0.310), immobilization (p: 0.119) and weight-bearing periods (p: 0.252) were statistically similar across both groups. Initial malreduction were observed in five cases within the three-screw group and one case in the two-screw group (p: 0.307). However, neither group exhibited any progressive step-off or gap in the follow-up radiographs, and osteotomy union was achieved in all patients. Delayed union was observed in one patient from the three-screw group. Significant improvements in American Orthopedic Foot and Ankle Society scores were observed in both groups, with no functional discrepancies evident at the final follow-up (p: 0.488). The study found no significant differences in union rates, complications, or clinical outcomes between two and three-screw fixation methods for medial malleolar osteotomies (MMO). Both methods allowed for effective MMO fixation without loss or displacement post-surgery, suggesting their safety and efficacy. Level III, retrospective comparison.

Deep-learning based 3D reconstruction of lower limb bones from biplanar radiographs for preoperative osteotomy planning

PurposeThree-dimensional (3D) preoperative planning has become the gold standard for orthopedic surgeries, primarily relying on CT-reconstructed 3D models. However, in contrast to standing radiographs, a CT scan is not part of the standard protocol but is usually acquired for preoperative planning purposes only. Additionally, it is costly, exposes the patients to high doses of radiation and is acquired in a non-weight-bearing position.MethodsIn this study, we develop a deep-learning based pipeline to facilitate 3D preoperative planning for high tibial osteotomies, based on 3D models reconstructed from low-dose biplanar standing EOS radiographs. Using digitally reconstructed radiographs, we train networks to localize the clinically required landmarks, separate the two legs in the sagittal radiograph and finally reconstruct the 3D bone model. Finally, we evaluate the accuracy of the reconstructed 3D models for the particular application case of preoperative planning, with the aim of eliminating the need for a CT scan in specific cases, such as high tibial osteotomies.ResultsThe mean Dice coefficients for the tibial reconstructions were 0.92 and 0.89 for the right and left tibia, respectively. The reconstructed models were successfully used for clinical-grade preoperative planning in a real patient series of 52 cases. The mean differences to ground truth values for mechanical axis and tibial slope were 0.52° and 4.33°, respectively.ConclusionsWe contribute a novel framework for the 2D–3D reconstruction of bone models from biplanar standing EOS radiographs and successfully use them in automated clinical-grade preoperative planning of high tibial osteotomies. However, achieving precise reconstruction and automated measurement of tibial slope remains a significant challenge.

Single-cut derotational osteotomy of the distal femur for correction of torsion and frontal axis

Arotational osteotomy requires acomplete cut of the bone in order to correct maltorsion. An additional correction of the frontal axis can be achieved via an oblique cut of the bone. The osteotomy with bone to bone contact is fixed with an angle stable plate. Symptoms such as anterior knee pain, inwardly pointing knee syndrome, lateral patellar subluxation or dislocation, lateral patellar hypercompression syndrome are a common indication for derivational osteotomy if clinically increased femoral internal rotation and radiologically increased femoral antetorsion is detected. Increased hip external rotation versus internal rotation, increased femoral torsion but no increased internal hip rotation, malcompliance, inability for partial weight bearing, risk of delayed union (nicotine abuse and obesity) as well as patellofemoral arthritis and systematic glucocorticoids, immunosuppressants are (relative) contra-indications. Alateral or optionally medial approach to the distal femur and exposure of the bone with Eva hooks for the osteotomy is done. The use of patient-specific cutting blocks accurately specify the planned extent of derotation and level of incision. Adefined oblique cutting plane of the single-cut osteotomy and derotation will additionally correct/change frontal axis. An additional biplanar osteotomy with an anterior wedge increases intraoperative stability and generates alarger bone contact area for consolidation. With the use of an extra medullary fixation devicepartial weight bearing with 15-20 kg with crutches up to 6weeks is required, but no restriction on knee movement is given. The literature shows significantly improved patient satisfaction regarding patellofemoral stability and knee function.With the use of patient-specific cutting guides, high accuracy of the osteotomy and 3‑dimensional correction can be achieved, while delayed union rate is up to 10%.

Conventional vs Augmented Reality-Guided Lateral Calcaneal Lengthening Simulated in a Foot Bone Model.

Acquired adult flatfoot deformity (AAFD) results in a loss of the medial longitudinal arch of the foot and dysfunction of the posteromedial soft tissues. Hintermann osteotomy (H-O) is often used to treat stage II AAFD. The procedure is challenging because of variations in the subtalar facets and limited intraoperative visibility. We aimed to assess the impact of augmented reality (AR) guidance on surgical accuracy and the facet violation rate. Sixty AR-guided and 60 conventional osteotomies were performed on foot bone models. For AR osteotomies, the ideal osteotomy plane was uploaded to a Microsoft HoloLens 1 headset and carried out in strict accordance with the superimposed holographic plane. The conventional osteotomies were performed relying solely on the anatomy of the calcaneal lateral column. The rate and severity of facet joint violation was measured, as well as accuracy of entry and exit points. The results were compared across AR-guided and conventional osteotomies, and between experienced and inexperienced surgeons. Experienced surgeons showed significantly greater accuracy for the osteotomy entry point using AR, with the mean deviation of 1.6 ± 0.9 mm (95% CI 1.26, 1.93) compared to 2.3 ± 1.3 mm (95% CI 1.87, 2.79) in the conventional method (P = .035). The inexperienced had improved accuracy, although not statistically significant (P = .064), with the mean deviation of 2.0 ± 1.5 mm (95% CI 1.47, 2.55) using AR compared with 2.7 ± 1.6 mm (95% CI 2.18, 3.32) in the conventional method. AR helped the experienced surgeons avoid full violation of the posterior facet (P = .011). Inexperienced surgeons had a higher rate of middle and posterior facet injury with both methods (P = .005 and .021). Application of AR guidance during H-O was associated with improved accuracy for experienced surgeons, demonstrated by a better accuracy of the osteotomy entry point. More crucially, AR guidance prevented full violation of the posterior facet in the experienced group. Further research is needed to address limitations and test this technology on cadaver feet. Ultimately, the use of AR in surgery has the potential to improve patient and surgeon safety while minimizing radiation exposure. Subtalar facet injury during lateral column lengthening osteotomy represents a real problem in clinical orthopaedic practice. Because of limited intraoperative visibility and variable anatomy, it is hard to resolve this issue with conventional means. This study suggests the potential of augmented reality to improve the osteotomy accuracy.

'One millimetre equals one degree' is a major source of inaccuracy in planning osteotomies around the knee for metaphyseal deformities compared to the digital planning.

The objective of this study was to compare the accuracy of virtually performed osteotomies around the knee. The comparison was made between the Miniaci method (method 1), considered the gold standard planning, with the widely held dogma that one degree of correction required equates to one millimetre of opening/closing (method 2). This retrospective cross-sectional study was conducted between December 2018 and September 2022 in patients aged at least 15 years with metaphyseal knee deformity. Osteotomy planning was performed in methods 1 and 2 utilising calibrated long-leg alignment X-rays in the frontal plane. In both methods, the desired correction was defined by the Fujisawa point. The error % in measurement (ratio method 1/method 2) and the difference in millimetres (method 1 - method 2) between the two methods were analysed. A total of 107 osteotomies with 27 (25.2%) distal femoral osteotomies, 54 (50.5%) proximal tibial osteotomies and 26 (24.3%) double-level osteotomies were performed virtually with a mean hip-knee-ankle angle of 176.4 ± 6.6. In distal femur osteotomy, the mean error % between methods 1 and 2 was 38.9 ± 16.7% and 22.4 ± 16.8% for the opening and closing groups, respectively. In proximal tibial osteotomies, the mean error % was 22.7 ± 15.6% and 9 ± 10.8% for the opening and closing groups, respectively. In double-level osteotomy, the mean error % of femur-based corrections was 34.9 ± 19% and 19.5 ± 21% for the opening and closing groups, respectively, and the mean error of the tibial-based corrections was 26.4 ± 12.1% for the opening group and 10.8 ± 10% for the closing group, respectively. Planning one millimeter per degree of desired correction for osteotomies around the knee in metaphyseal deformities is a major source of error when compared with digital planning using the Miniaci method. This was seen most frequently with osteotomies of the distal femur and all opening wedge osteotomies. Level Ⅲ, retrospective cross-sectional study.

Accuracy of the modified tooth-supported 3D printing surgical guides based on CT, CBCT, and intraoral scanning in maxillofacial region: A comparison study

BackgroundTooth-supported surgical guides have demonstrated superior accuracy compared with bone-supported guides. This study aimed to modify the fabrication of tooth-supported guides for compatibility with tumor resection procedures and investigate their accuracy. MethodsPatients with tumors who underwent osteotomy with the assistance of modified tooth- or bone-supported surgical guides were included. Virtual surgical planning (VSP) was employed to align three dimensional (3D) models extracted from intraoperative computed tomography (CT) images. The distances and angular deviations between the actual osteotomy plane and preoperative plane were recorded. A comparative analysis of osteotomy discrepancies between tooth-supported and bone-supported guides, as well as among tooth-supported guides based on CT, cone-beam CT (CBCT), or intraoral scanner (IOS) was conducted. The factors influencing the precision of the guides were analyzed. ResultsSixty patients with 81 resection planes were included in this study. In the tooth-supported group, the mean deviations in the osteotomy plane and angle were 1.39 mm and 4.30°, respectively, whereas those of the bone-supported group were 2.16 mm and 4.95°. In the tooth-supported isotype guide groups, the mean deviations of the osteotomy plane were 1.39 mm, 1.47 mm, 1.23 mm across CT, CBCT, and IOS, respectively. The accuracy of the modified tooth-supported guides remained consistent regardless of number and position of the teeth supporting the guide and location of the osteotomy lines. ConclusionsThe findings indicate that the modified tooth-supported surgical guides demonstrated high accuracy in the maxillofacial region, contributing to a reduction in the amount of surgically detached soft tissue.