Mandibular Reconstructive Surgery Research Articles

To what extent can mastication functionality be restored following mandibular reconstruction surgery? A computer modeling approach

Statement of ProblemAdvanced cases of head and neck cancer involving the mandible often require surgical removal of diseased sections and subsequent replacement with donor bone. During the procedure, the surgeon must make decisions regarding which bones or tissues to resect. This requires balancing tradeoffs related to issues such as surgical access and post-operative function; however, the latter is often difficult to predict, especially given that long-term functionality also depends on the impact of post-operative rehabilitation programs. PurposeTo assist in surgical decision-making, we present an approach for estimating the effects of reconstruction on key aspects of post-operative mandible function. Material and MethodsWe develop dynamic biomechanical models of the reconstructed mandible considering different defect types and validate them using literature data. We use these models to estimate the degree of functionality that might be achieved following post-operative rehabilitation. ResultsWe find significant potential for restoring mandibular functionality, even in cases involving large defects. This entails an average trajectory error below 2 mm, bite force comparable to a healthy individual, improved condyle mobility, and a muscle activation change capped at a maximum of 20%. ConclusionThese results suggest significant potential for adaptability in the masticatory system and improved post-operative rehabilitation, leading to greater restoration of jaw function.

Impact of virtual surgical planning and three-dimensional modeling on time to surgery in mandibular reconstruction by free fibula flap

PurposeMandible reconstruction using a free fibula flap (FFF) is preferably performed with virtual surgical planning (VSP) to potentially improve functional and aesthetic outcomes. However, VSP is time-consuming. This study aims to assess the impact of VSP on time to surgery (TS). Materials and methodsAll patients who underwent FFF for oral cavity cancer between 2007 and 2020 were included. Time to surgery (from the date of the first consultation to the surgery date) was compared between patients without VSP and with VSP. In our department, VSP and 3D modeling were performed by an external engineering laboratory. ResultsOne hundred sixty-five patients were included retrospectively. VSP was utilized for 90 patients (55%). The mean time to surgery was 31 ± 16 days for patients undergoing conventional surgery without VSP and 44 ± 19 days for patients with VSP (p < 0.001). No clinical or tumoral characteristic were associated with a TS extended, except for the utilization of VSP (p < 0.001). By constituting groups of 25 consecutive patients, there is no difference in TS between the groups. ConclusionThe use of VSP significantly increased the time to surgery in our study, unrelated to clinical differences or year of surgery. This delay may have an impact on oncologic outcomes, so it should be considered in the care organization for each patient. Implementing new procedures to reduce this difference is warranted.

Reduced length of intensive care unit stay and early mechanical ventilator weaning with enhanced recovery after surgery (ERAS) in free fibula flap surgery

This study aimed to evaluate the effects of the enhanced recovery after surgery (ERAS) program on postoperative recovery of patients who underwent free fibula flap surgery for mandibular reconstruction. This retrospective study included 188 patients who underwent free fibula flap surgery for complex mandibular and soft tissue defects between January 2011 and December 2022. We divided them into two groups: the ERAS group, consisting of 36 patients who were treated according to the ERAS program introduced from 2021 to 2022. Propensity score matching was used for the non-ERAS group, which comprised 36 cases selected from 152 patients between 2011 and 2020, based on age, sex, and smoking history. After propensity score matching, the ERAS and non-ERAS groups included 36 patients each. The primary outcome was the length of intensive care unit (ICU) stay; the secondary outcomes were flap complications, unplanned reoperation, 30-day readmission, postoperative ventilator use length, surgical site infections, incidence of delirium within ICU, lower-limb comorbidities, and morbidity parameters. There were no significant differences in the demographic characteristics of the patients. However, the ERAS group showed the lower length of intensive care unit stay (ERAS vs non-ERAS: 8.66 ± 3.90 days vs. 11.64 ± 5.42 days, P = 0.003) and post-operative ventilator use days (ERAS vs non-ERAS: 1.08 ± 0.28 days vs. 2.03 ± 1.05 days, P < 0.001). Other secondary outcomes were not significantly different between the two groups. Additionally, patients in the ERAS group had lower postoperative morbidity parameters, such as postoperative nausea, vomiting, urinary tract infections, and pulmonary complications (P = 0.042). The ERAS program could be beneficial and safe for patients undergoing free fibula flap surgery for mandibular reconstruction, thereby improving their recovery and not increasing flap complications and 30-day readmission.

Mandibular reconstruction using an iliac bone flap with perforator-supported external oblique abdominal muscle island: a pilot study

The deep circumflex iliac artery (DCIA) flap is one of the bone flaps commonly used for mandibular reconstruction. Observation of the skin paddle and Doppler ultrasound are methods that are usually used to monitor DCIA flaps after mandibular reconstruction surgery. The aim of this study was to introduce a novel DCIA flap with a perforator-supported external oblique abdominal muscle (EOAM) island for postoperative flap monitoring. This study included five patients who underwent mandibular reconstruction using this modified technique. The DCIA flap and the EOAM island supplied by the ascending branch of the DCIA were harvested during the surgery. After mandibular reconstruction, the EOAM island was placed in the submandibular region to monitor the blood supply to the DCIA flap after surgery. The blood supply to the DCIA flap was monitored by observing the colour, texture, and bleeding condition of the EOAM island. After the monitoring period, the EOAM was removed and the ascending branch of the DCIA was ligated. The outcome was successful in all patients. The EOAM island supported by the ascending branch of the DCIA is reliable and safe, thus providing a robust option to monitor the blood supply to the DCIA flap.

Fibular free flap necrosis after mandibular reconstruction surgery with osteoradionecrosis: Establishment and verification of an early warning model

ObjectiveFibular free flap necrosis (FFFN) is the most common complication in patients with osteoradionecrosis (ORN) after mandibular reconstruction surgery. However, there are no effective forecasting tools at present. This research is aimed to establish and verify a nomogram model to predict the risk of FFFN after mandibular reconstruction surgery in ORN patients. MethodsA total of 193 ORN patients with mandibular reconstruction using fibular free flap (150 cases in the model group and 43 cases in the validation group) were enrolled in this study. In the model group, the variables were optimized by lasso regression. Then the prediction model was established by binary logistic regression analysis, and the nomogram was drawn. The bootstrap self-sampling method was used for internal verification. Moreover, 43 cases in the validation group were used for external validation. ResultsThe results of lasso regression and binary logistic regression analysis showed that the radiotherapy interval (≤2 years), trismus, diabetes, without deep venous anastomoses, and American society of anesthesiologists (ASA) III were the independent risk factors for FFFN after mandibular reconstruction surgery in ORNJ patients (P<0.05). Based on the above-mentioned risk factors, the nomogram model was established. The AUC values of the model group and the validation group were 0.936 and 0.964, respectively. The curve analysis showed that when the probability thresholds of the model group and the validation group were 5.699%∼98.229% and 0.413%∼99.721%, respectively. So the patient's clinical net profit rate was the highest. ConclusionA nomogram combining the factors of radiotherapy interval (≤2 years), trismus, diabetes, without deep venous anastomoses, and ASA III provided a comparatively effective way to predict the risk of FFFN after mandibular reconstruction surgery in ORN patients, which has distinct applied clinical value.

Robot-assisted augmented reality surgical navigation based on optical tracking for mandibular reconstruction surgery.

This work proposes a robot-assisted augmented reality (AR) surgical navigation system for mandibular reconstruction. The system accurately superimposes the preoperative osteotomy plan of the mandible and fibula into a real scene. It assists the doctor in osteotomy quickly and safely under the guidance of the robotic arm. The proposed system mainly consists of two modules: the AR guidance module of the mandible and fibula and the robot navigation module. In the AR guidance module, we propose an AR calibration method based on the spatial registration of the image tracking marker to superimpose the virtual models of the mandible and fibula into the real scene. In the robot navigation module, the posture of the robotic arm is first calibrated under the tracking of the optical tracking system. The robotic arm can then be positioned at the planned osteotomy after the registration of the computed tomography image and the patient position. The combined guidance of AR and robotic arm can enhance the safety and precision of the surgery. The effectiveness of the proposed system was quantitatively assessed on cadavers. In the AR guidance module, osteotomies of the mandible and fibula achieved mean errors of 1.61 ± 0.62 and 1.08 ± 0.28mm, respectively. The mean reconstruction error of the mandible was 1.36 ± 0.22mm. In the AR-robot guidance module, the mean osteotomy errors of the mandible and fibula were 1.47 ± 0.46 and 0.98 ± 0.24mm, respectively. The mean reconstruction error of the mandible was 1.20 ± 0.36mm. The cadaveric experiments of 12 fibulas and six mandibles demonstrate the proposed system's effectiveness and potential clinical value in reconstructing the mandibular defect with a free fibular flap.

Long-Term Follow-Up of a Novel Surgical Option Combining Fibula Free Flap and 3D-Bioprinted, Patient-Specific Polycaprolactone (PCL) Implant for Mandible Reconstruction

As the fibula free flap became the gold standard in mandibular reconstruction that required both hard tissue and soft tissue, various methods have been sought to solve the height discrepancy between the mandible and fibula. The purpose of this paper was to propose a surgical option that combined the microvascular fibula free flap with a 3D-bioprinted, patient-specific polycaprolactone (PCL) implant as a safe and simple novel method that achieved the best functional and aesthetic results in mandibular reconstruction surgery for young patients with malignant tumors. The patient’s reconstructed mandible maintained volume symmetry without any deformation or complications for over 6 years. Computer-aided design/computer-aided manufacturing (CAD/CAM) and 3D printing technology enabled accurate and safe surgical results.

A collaborative robotic platform for sensor-aware fibula osteotomies in mandibular reconstruction surgery

Precision and safety are crucial in performing fibula osteotomy during mandibular reconstruction with free fibula flap (FFF). However, current clinical methods, such as template-guided osteotomy, have the potential to cause damage to fibular vessels. To address the challenge, this paper introduces the development of the surgical robot for fibula osteotomies in mandibular reconstruction surgery and propose an algorithm for sensor-aware hybrid force–motion control for safe osteotomy, which includes three parts: osteotomy motion modeling from surgeons’ demonstrations, Dynamic-system-based admittance control and osteotomy sawed-through detection. As a result, the average linear variation of the osteotomized segments was 1.08±0.41mm, and the average angular variation was 1.32±0.65∘. The threshold of osteotomy sawed-through detection is 0.5 at which the average offset is 0.5mm. In conclusion, with the assistance of surgical robot for mandibular reconstruction, surgeons can perform fibula osteotomy precisely and safely.

Accuracy of virtual surgical planning in mandibular reconstruction: application of a standard and reliable postoperative evaluation methodology

ObjectiveThe purpose of this study was to determine the accuracy of virtual surgical planning for mandibular reconstruction, along with the implementation of a postoperative evaluation methodology.Materials and methodsThe study is a prospective case series for computer-assisted mandibular reconstruction surgery. Analysis of the degree of agreement between virtual measurements and postoperative actual outcomes was performed. The reliability of the proposed evaluation methodology was assessed and analyzed using the Inter-Class Coefficient (ICC) test. Statistical significance was set at the 5% level.ResultsNine consecutive patients were selected. The analysis of all angular and linear parameters reported a highly statistically significant degree of agreement between the preoperative and postoperative measurements (P < 0.001). Furthermore, an extreme degree of reliability was reported when the evaluation methodology was scrutinized (ICC = 0.9).ConclusionThe excellent degree of agreement between the virtual plan and the actual outcome reported in this study validated the surgical accuracy of virtually assisted mandibular reconstruction. This study pointed out the reliability and reproducibility of the standardized evaluation protocol in an attempt to obtain a tolerable value for the acceptable postoperative results regarding the accuracy of computer-assisted surgery.

Pain severity and quality of life following major mandibular reconstructive surgery in head neck cancer

Pain severity and quality of life following major mandibular reconstructive surgery in head neck cancer

Design and implementation of a surgical planning system for robotic assisted mandible reconstruction with fibula free flap.

Free fibula flap is the gold standard for the treatment of mandibular defects. However, the existing preoperative planning protocol is cumbersome to execute, costly to learn, and poorly collaborative with the robot-assisted cutting of the fibular osteotomy plane. A surgical planning system for robotic assisted mandibular reconstruction with fibula free flap is proposed in this study. A fibular osteotomy planning algorithm is presented so that the virtual surgical planning of the fibular osteotomy segments can be obtained automatically with selected mandibular anatomical landmarks. The planned osteotomy planes are then converted into the motion path of the robotic arm, and the automatic fibula osteotomy is completed under optical navigation. Surgical planning was performed on 35 patients to verify the feasibility of our system's virtual surgical planning module, with an average time of 13min. Phantom experiments were performed to evaluate the reliability and stability of this system. The average distance and angular deviations of the osteotomy planes are 1.04 ± 0.68mm and 1.56 ±1.10°, respectively. Our system can achieve not only precise and convenient preoperative planning, but also safe and reliable osteotomy trajectory. The clinical applications of our system for mandibular reconstruction surgery are expected soon.

Biomechanical integrity of hydroxyapatite/poly-l-lactide fixation system in mandibular body reconstruction with deep circumflex iliac artery free flap

The mechanical integrity of a deep circumflex iliac artery (DCIA) free flap connected to the remaining mandible after a segmental mandibulectomy directly influences the reconstructive surgery prognosis. This study aimed to assess the biomechanical integrity of fixation systems on the reconstruction site. The mechanical properties of mini-plate and screw fixations in two different materials, namely titanium (Ti) and hydroxyapatite/poly-L-lactide (HA-PLLA), were simulated using finite element analysis. Each end of the free flap was fixed with three mini-plates, a total of six mini-plates at the midline and the anterior to the coronoid process with 35 screws. The masticatory loading increment effect on peak von Mises stress (PVMS) distribution, size of fixation deformation, principal stresses on bones, and a gap opening size were taken into account for each material's pros and cons evaluation. Based on the comprehensive evaluation, the Ti fixation system presented superior performance immediately after surgery. However, the Ti fixation system's superiority was diminishing over time, and eventually, the differences became marginal at 12-months postop. This study's results imply the clinical indications of the HA-PLLA fixation system with the DCIA free flap during mandibular reconstructive surgery.

A hybrid registration method using the mandibular bone surface for electromagnetic navigation in mandibular surgery.

To utilize navigated mandibular (reconstructive) surgery, accurate registration of the preoperative CT scan with the actual patient in the operating room (OR) is required. In this phantom study, the feasibility of a noninvasive hybrid registration method is assessed. This method consists of a point registration with anatomic landmarks for initialization and a surface registration using the bare mandibular bone surface for optimization. Three mandible phantoms with reference notches on two osteotomy planes were 3D printed. An electromagnetic tracking system in combination with 3D Slicer software was used for navigation. Different configurations, i.e., different surface point areas and number and configuration of surface points, were tested with a dentate phantom (A) in a metal-free environment. To simulate the intraoperative environment and different anatomies, the registration procedure was also performed with an OR bed using the dentate phantom and two (partially) edentulous phantoms with atypical anatomy (B and C). The accuracy of the registration was calculated using the notches on the osteotomy planes and was expressed as the target registration error (TRE). TRE values of less than 2.0mm were considered as clinically acceptable. In all experiments, the mean TRE was less than 2.0mm. No differences were found using different surface point areas or number or configurations of surface points. Registration accuracy in the simulated intraoperative setting was-mean (SD)-0.96 (0.22), 0.93 (0.26), and 1.50 (0.28) mm for phantom A, phantom B, and phantom C. Hybrid registration is a noninvasive method that requires only a small area of the bare mandibular bone surface to obtain high accuracy in phantom setting. Future studies should test this method in clinical setting during actual surgery.

Computer-Aided Surgery for Presurgical Planning Versus Conventional Freehand Surgery in Mandibular Reconstruction Using Free Fibular Flap: A Systematic Review and Meta-Analysis

Computer-Aided Surgery for Presurgical Planning Versus Conventional Freehand Surgery in Mandibular Reconstruction Using Free Fibular Flap: A Systematic Review and Meta-Analysis

Mandibular Reconstruction with Iliac Crest Graft Associated with L-PRF and Hyperbaric Oxygen Therapy: A Case Report

Maxillofacial reconstructions with free grafts have become a routine reality for plastic surgeons and maxillofacial surgeons in the last decade. This condition usually occurs after radical treatment of benign or malignant pathologies of the stomatognathic complex, through en bloc resections with a safety margin to reduce the chances of recurrence of the pathology. One of the great challenges faced by surgical teams is no longer just in relation to the technique used for planning, but the predictability and maintenance of the graft performed in the face of systemic changes that can compromise the success of the graft, such as diabetes mellitus. Several aspects have been explored in recent years, such as the use of ozone, synthetic membranes, formation of Leukocyte and Platelet Rich Fibrin (L-PRF) and hyperbaric therapy in the quest to maximize the chances of graft success, reducing the chances of infection and bone resorption mainly through osteoinductive and osteogenic stimuli, which are not characteristics present in a metabolic dysfunction such as diabetes. Another important data for these types of surgery is the bone quality offered by the donor bed, because in maxillofacial reconstructions, a balance in the amount of corticalized bone and medullary bone is important, which leads us to characteristics such as the best donor bed for these surgical reconstructions in the iliac crest region. Here the authors present a case of 64 years old male hypertensive patient with h/o diabetes mellitus, managed by a mandibular reconstruction surgery with iliac crest graft associated with L-PRF and hyperbaric oxygen therapy after extensive resection of a benign mandibular tumour in a patient with diabetes mellitus.

A 3D segmentation network of mandible from CT scan with combination of multiple convolutional modules and edge supervision in mandibular reconstruction

Mandibular reconstruction is a very complex surgery that demands removing the tumor, which is followed by reconstruction of the defective mandible. Accurate segmentation of the mandible plays an important role in its preoperative planning. However, there are many segmentation challenges including the connected boundaries of upper and lower teeth, blurred condyle edges, metal artifact interference, and different shapes of the mandibles with tumor invasion (MTI). Those manual or semi-automatic segmentation methods commonly used in clinical practice are time-consuming and have poor effects. The automatic segmentation methods are mainly developed for the mandible without tumor invasion (Non-MTI) rather than MTI and have problems such as under-segmentation. Given these problems, this paper proposed a 3D automatic segmentation network of the mandible with a combination of multiple convolutional modules and edge supervision. Firstly, the squeeze-and-excitation residual module is used for feature optimization to make the network focused more on the mandibular segmentation region. Secondly, the multi atrous convolution cascade module is adapted to implement a multi-scale feature search to extract more detailed features. Considering that most mandibular segmentation networks ignore the boundary information, the loss function combining region loss and edge loss is applied to further improve the segmentation performance. The final experiment shows that the proposed network can segment Non-MTI and MTI quickly and automatically with an average segmentation time of 7.41s for a CT scan. In the meantime, it also has a good segmentation accuracy. For Non-MTI segmentation, the dice coefficient (Dice) reaches 97.98 ± 0.36%, average surface distance (ASD) reaches 0.061 ± 0.016 mm, and 95% Hausdorff distance (95HD) reaches 0.484 ± 0.027 mm. For Non-MTI segmentation, the Dice reaches 96.90 ± 1.59%, ASD reaches 0.162 ± 0.107 mm, and 95HD reaches 1.161 ± 1.034 mm. Compared with other methods, the proposed method has better segmentation performance, effectively improving segmentation accuracy and reducing under-segmentation. It can greatly improve doctor's segmentation efficiency and will have a promising application prospect in mandibular reconstruction surgery in the future.

THE ROLE OF 3D MODEL AS SURGICAL GUIDANCE IN MANDIBULAR RECONSTRUCTION SURGERY

reconstruction surgery is a challenging surgery that require well prepared presurgical plan to minimize the risk of failure, to accommodate the need for precision preoperative planning, surgeons frequently need guidance such as a3-dimensional (3D) model to display complex cranial structures. Evaluation of the 3D model as surgical guidance require a review measurement regarding its efficiency and pitfalls. Purpose: the purpose of this research is to understand the importants key points that will resulted succesfull reconstructive surgery using 3D model as surgical guidance. Method: the evaluation of surgical result in mandibular reconstruction surgery from our Department Oral and Maxillofacial surgery, Universitas Indonesia from 2012 to 2017 reveal the differences. We analyze several keypoints that may affect to the succesfull of reconstruction surgery result. Result: we compared the result between years before and after 2015, this is where we start obligate all reconstruction surgery need to have preoperative planning using3D Model. Several keypoints in using 3D model is acknowledgeable. Conclusion: the use of 3D models as surgical guidance has important role to minimize post reconstructive surgery result, surgeon need to understand the principal and keypoints in preoperative planning and regarding the use of 3D model.

Multicentre evaluation of the interest in planned surgery for mandibular reconstruction with fibula free flap: a retrospective cohort study.

The aim of this study was to determine the impact and cost-effectiveness of virtual surgical planning during fibula free flap mandibular reconstruction on peri- and postoperative data. We conducted a retrospective cohort study from January 2012 to December 2016 in four French university centres. Three hundred fibula free flaps for mandibular reconstruction were performed in 294 patients. Surgeries were planned in 29.7% of cases (n = 89). There was no significant difference in the rate of negative-margins excision, median length of hospital stay, operative time, and early complications between planned and non-planned surgeries. Morphological analysis revealed a higher rate of centred occlusion in planned patients (satisfactory alignment of interincisal points: Planned 65.5% vs Non-Planned 33.3%, p = 0.006). In mandibular reconstruction by fibula free flap, the additional cost generated by virtual surgical planning does not seem to be balanced by savings resulting from a shorter operative course, a reduced hospital stay, or a reduction in postoperative complications. However, virtual surgical planning may provide a higher rate of centred occlusion. Long-term benefits should be assessed by further studies.

Reconstruction of Mandible with Free Fibula Flap:Report of Three Cases

Mandibular reconstructive surgery has changed in the recent times with the introduction of advanced techniques. Mandibular reconstruction a challenge for the reconstructive surgeons, is now reliable and highly successful with excellent long-term functional and aesthetic outcomes using vascularised fibular flap in various mandibular pathologies. The ideal reconstruction should restore the anatomic contour, speech, mastication and aesthetics. The free vascularised fibular flap is the primary source of bone for reconstruction of large segmental mandibular defects due to its rich vascularity. We present three cases of segmental mandibular defects reconstructed primarily with vascularised free fibular flap without skin paddle which were followed up for two years.

Malocclusion Management Following Mandibular Reconstruction With Free Fibula Flaps.

Free fibula flaps are nowadays the gold standard for the surgical reconstruction on large mandibular defects. Malocclusion is an important complication of this type of reconstruction and many of these patients end up requiring subsequent orthognathic corrective surgery. This is a descriptive retrospective case series study. To describe the demographic data, operative techniques, corrective methods and postoperative results in the management of malocclusion following mandibular reconstruction with free fibula flap. This case series study included patients who underwent free fibula flap mandibular reconstructions and who that subsequently developed malocclusion requiring orthognathic corrective surgery, from June 2010 to December 2019. Panoramic X-rays, cephalometries and/or 3-D facial reconstruction CT scans were used for surgical planning to create surgical cutting guides, templates and occlusal splints in all the patients that underwent corrective orthognathic surgery. There were 46 patients who underwent a free fibula flap mandibular and maxillary reconstruction at San Jose Hospital between June 2010 and December 2019 of these, 5 patients (10.9%) developed postoperative malocclusion. One case from another institution was added to this study for a total of 6 patients with malocclusion following mandibular reconstruction surgery with a fibula free flap. During the orthognathic surgery, vertical osteotomies were performed in 3 patients and bilateral sagittal split osteotomies were necessary in 2 patients and L-shape in 1 patient. Osteogenic distraction was performed in 3 patients as part of their orthognathic treatment. The fixation methods were based in miniplates for 3 of the patients and lag screws for the remaining 3 patients. With this approach, all patients had an adequate occlusion correction with a 100% consolidation at their 6-month follow up. Malocclusion is a significant complication following mandibular reconstruction surgery that must be identified and managed. In severe cases, it requires corrective orthognathic surgery in severe cases. We have developed a protocol to avoid pitfalls during the primary reconstruction and in case an orthognathic surgery is required for malocclusion correction, preoperative planning with cutting guides and occlusal splints should be assessed, to guarantee favorable results through a reproducible technique.