Mandibular reconstruction with vascularised bone flaps: a systematic review over 25 years

Can growing patients with end-stage TMJ pathology be successfully treated with alloplastic temporomandibular joint reconstruction? - A systematic review

INTRODUCTION

The use of alloplastic total temporomandibular joint reconstruction (TMJR) in growing patients is controversial, mainly due to immature elements of the craniomaxillofacial skeleton. The aim of this systematic review was to evaluate the use of alloplastic TMJR in growing patients, focusing on the patient's clinical presentation, surgical and medical history and efficacy of alloplastic TMJR implantation.

MATERIALS AND METHODS

The literature search strategy was based on the Population, Intervention, Comparator, Outcomes and Study type (PICOS) framework. We searched Pubmed, Google Scholar, Dimension, Web of Science, X-mol, Semantic Scholar and Embase to January 2023, without any restriction on the type of publication reporting alloplastic TMJR in growing patients (age ≤ 18 years for boys and age ≤ 15 years for girls).

RESULTS

A total of 15 studies (case reports: 09, case series: 02, cohort studies: 04) met the inclusion criteria, documenting 73 patients of growing age from 07 countries. Thirty-eight (~ 52%) cases were female. The mean ± SD (range) age and follow-up of patients in all studies was 13.1 ± 3.2 (0-17) years and 34.3 ± 21.5 (7-96) months, respectively. A total of 22 (30%) patients were implanted with bilateral alloplastic TMJR. Over half of the studies (n = 10) were published in the last 3 years. All patients underwent multiple surgeries prior to implantation of alloplastic TMJR. In extreme cases, patients underwent a total of 17 surgeries. Different types of studies reporting inconsistent variables restricted our ability to perform quality assessment measures for evidence building.

CONCLUSIONS

Clinical experience with alloplastic TMJR in growing patients is limited to cases showing poor prognosis with other types of reconstruction. Nevertheless, studies show promising results for the use of alloplastic TMJR in growing patients, highlighting the need for well-controlled prospective studies with long-term follow-up.

A Preclinical Trial Protocol Using an Ovine Model to Assess Scaffold Implant Biomaterials for Repair of Critical-Sized Mandibular Defects

The present work describes a preclinical trial (in silico, in vivo and in vitro) protocol to assess the biomechanical performance and osteogenic capability of 3D-printed polymeric scaffolds implants used to repair partial defects in a sheep mandible. The protocol spans multiple steps of the medical device development pipeline, including initial concept design of the scaffold implant, digital twin in silico finite element modeling, manufacturing of the device prototype, in vivo device implantation, and in vitro laboratory mechanical testing. First, a patient-specific one-body scaffold implant used for reconstructing a critical-sized defect along the lower border of the sheep mandible ramus was designed using on computed-tomographic (CT) imagery and computer-aided design software. Next, the biomechanical performance of the implant was predicted numerically by simulating physiological load conditions in a digital twin in silico finite element model of the sheep mandible. This allowed for possible redesigning of the implant prior to commencing in vivo experimentation. Then, two types of polymeric biomaterials were used to manufacture the mandibular scaffold implants: poly ether ether ketone (PEEK) and poly ether ketone (PEK) printed with fused deposition modeling (FDM) and selective laser sintering (SLS), respectively. Then, after being implanted for 13 weeks in vivo, the implant and surrounding bone tissue was harvested and microCT scanned to visualize and quantify neo-tissue formation in the porous space of the scaffold. Finally, the implant and local bone tissue was assessed by in vitro laboratory mechanical testing to quantify the osteointegration. The protocol consists of six component procedures: (i) scaffold design and finite element analysis to predict its biomechanical response, (ii) scaffold fabrication with FDM and SLS 3D printing, (iii) surface treatment of the scaffold with plasma immersion ion implantation (PIII) techniques, (iv) ovine mandibular implantation, (v) postoperative sheep recovery, euthanasia, and harvesting of the scaffold and surrounding host bone, microCT scanning, and (vi) in vitro laboratory mechanical tests of the harvested scaffolds. The results of microCT imagery and 3-point mechanical bend testing demonstrate that PIII-SLS-PEK is a promising biomaterial for the manufacturing of scaffold implants to enhance the bone-scaffold contact and bone ingrowth in porous scaffold implants. MicroCT images of the harvested implant and surrounding bone tissue showed encouraging new bone growth at the scaffold-bone interface and inside the porous network of the lattice structure of the SLS-PEK scaffolds.

Oral rehabilitation and associated quality of life following mandibular reconstruction with free fibula flap: a cross-sectional study

Introduction

Mandibular reconstruction with the free fibula flap (FFF) has become a standardized procedure. The situation is different with oral rehabilitation, so the purpose of this study was to investigate the frequency of implant placement and prosthetic restoration. Additionally, the patients' situation, motivation, and treatment course were structurally assessed.

Materials and methods

All cases between January 2013 and December 2018 that underwent mandibular reconstruction in our department with a free fibula flap and gave written informed consent to participate were interviewed with two structured questionnaires about their restoration and quality of life. Additionally, medical records, general information, status of implants and therapy, and metric analyses of the inserted implants were performed.

Results

In total 59 patients were enrolled and analyzed in this monocentric study. Overall, oral rehabilitation was achieved in 23.7% at the time of investigation. In detail, implants were inserted in 37.3% of patients and showed an 83.3% survival of dental implants. Of these implanted patients, dental implants were successfully restored with a prosthetic restoration in 63.6. Within this subgroup, satisfaction with the postoperative aesthetic and functional result was 79.9% and with the oral rehabilitation process was 68.2%. Satisfaction with the implant-borne prosthesis was 87.5%, with non-oral-squamous-cell-carcinoma patients being statistically significantly more content with the handling (p=0.046) and care (p=0.031) of the prosthesis.

Discussion

Despite the well-reconstructed bony structures, there is a need to increase the effort of achieving oral rehabilitation, especially looking at the patient's persistent motivation for the procedure.

Continuous Monitoring of Buried Free Bone Flap Microcirculation Using a Near-Infrared Spectroscopy System

SUMMARY

Postoperative evaluation of free flaps remains a challenging task. The current accepted standard for diagnosis of vascular compromise remains clinical observation. In recent years, near-infrared spectroscopy (NIRS) has been widely used as a noninvasive objective monitoring tool for postoperative evaluation of soft-tissue flaps. However, methods for monitoring bone flaps remain inadequate. In this study, NIRS was applied for the first time to monitor free buried bone flaps that were used for mandibular reconstruction. The penetrating property of NIRS was used to measure the tissue oxygenation index (TOI) of deep tissues, which reflected the microcirculatory status of the tissues. Changes in TOI values were monitored continuously in 59 cases of free bone flaps up to 72 hours after surgery. Five cases of vascular compromise were noted by clinical observation. Two fibula flaps were total failures, one of which showed a sharp decrease in TOI value to 45% in a short period of time; the other showed a continual gradual decrease to 55%. The observed sudden (<50%) and continuous (>10%) decreases in TOI values suggest that more attention should be paid to revision surgical procedures. The authors conclude that NIRS holds promise as an objective and valid method for clinical evaluation of buried bone flaps.

Computational models and their applications in biomechanical analysis of mandibular reconstruction surgery

Advanced head and neck cancers involving the mandible often require surgical removal of the diseased parts and replacement with donor bone or prosthesis to recreate the form and function of the premorbid mandible. The degree to which this reconstruction successfully replicates key geometric features of the original bone critically affects the cosmetic and functional outcomes of speaking, chewing, and breathing. With advancements in computational power, biomechanical modeling has emerged as a prevalent tool for predicting the functional outcomes of the masticatory system and evaluating the effectiveness of reconstruction procedures in patients undergoing mandibular reconstruction surgery. These models offer cost-effective and patient-specific treatment tailored to the needs of individuals. To underscore the significance of biomechanical modeling, we conducted a review of 66 studies that utilized computational models in the biomechanical analysis of mandibular reconstruction surgery. The majority of these studies employed finite element method (FEM) in their approach; therefore, a detailed investigation of FEM has also been provided. Additionally, we categorized these studies based on the main components analyzed, including bone flaps, plates/screws, and prostheses, as well as their design and material composition.

Trends in free flap reconstruction of the head and neck: a single surgeon series of 1027 free tissue transfers

BACKGROUND

Free tissue transfer has fundamentally changed head and neck surgery, enabling reliable reconstruction of large defects with better function and aesthetics. This study assesses two decades of trends in free flap reconstruction, and how disease incidence, survival, surgeon caseload, team approach, and technology have impacted practice.

METHODS

Retrospective analysis of 1027 head and neck free flaps from 2006 to 2022. Outcomes examined include chronological changes in flap selection, indication, length of stay, incorporation of virtual surgical planning (VSP), annual caseload, survival, and their associations with the single versus multi-team approach.

RESULTS

There were 764 soft-tissue and 263 osseous reconstructions utilizing 21 different flaps. Anterolateral thigh and radial forearm accounted for 76.7% of soft tissue flaps, with recent increase in superficial circumflex iliac perforator flaps in young patients. Osseous flap proportion remained stable, but fibula flaps increased five-fold with more VSP, dental implants, oral cancer, and multi-team surgery. Outcomes such as complication rates, length of stay and disease specific/overall survival have improved over time despite increasing complexity (P = 0.001, P = 0.001, P < 0.001, and P < 0.001, respectively). However, there was no significant difference in operative time, complication rate, or disease specific/overall survival between single team or multi-team approaches (P = 0.45, P = 0.054, P = 0.57, and P = 0.60, respectively).

CONCLUSION

Single and multi-team approaches may have similar fundamental outcomes, but as caseload, complexity, and life-expectancy increases, both patients and surgeons benefit from a collaborative multi-team approach that focuses on improving long-term functional outcomes.

Biomechanical evaluation of CAD/CAM magnesium miniplates as a fixation strategy for the treatment of segmental mandibular reconstruction with a fibula free flap

Titanium patient-specific (CAD/CAM) plates are frequently used in mandibular reconstruction. However, titanium is a very stiff, non-degradable material which also induces artifacts in the imaging. Although magnesium has been proposed as a potential material alternative, the biomechanical conditions in the reconstructed mandible under magnesium CAD/CAM plate fixation are unknown. This study aimed to evaluate the primary fixation stability and potential of magnesium CAD/CAM miniplates. The biomechanical environment in a one segmental mandibular reconstruction with fibula free flap induced by a combination of a short posterior titanium CAD/CAM reconstruction plate and two anterior CAD/CAM miniplates of titanium and/or magnesium was evaluated, using computer modeling approaches. Output parameters were the strains in the healing regions and the stresses in the plates. Mechanical strains increased locally under magnesium fixation. Two plate-protective constellations for magnesium plates were identified: (1) pairing one magnesium miniplate with a parallel titanium miniplate and (2) pairing anterior magnesium miniplates with a posterior titanium reconstruction plate. Due to their degradability and reduced stiffness in comparison to titanium, magnesium plates could be beneficial for bone healing. Magnesium miniplates can be paired with titanium plates to ensure a non-occurrence of plate failure.

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

PURPOSE

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.

METHODS

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.

RESULTS

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 ± 0.28 mm, respectively. The mean reconstruction error of the mandible was 1.36 ± 0.22 mm. In the AR-robot guidance module, the mean osteotomy errors of the mandible and fibula were 1.47 ± 0.46 and 0.98 ± 0.24 mm, respectively. The mean reconstruction error of the mandible was 1.20 ± 0.36 mm.

CONCLUSIONS

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.

Deep Circumflex Iliac Artery Flap Reconstruction in Brown Class I Defect of the Mandible Using a Three-Component Surgical Template System

BACKGROUND

Computer-assisted surgery is widely used in mandibular reconstruction, but the process is not well described for cases using the deep circumflex iliac artery flap (DCIA) as the donor site. This study aimed to present a DCIA-based three-component surgical template system (3-STS) in patients with a mandibular Brown class I defect.

METHODS

This retrospective cohort study compared clinical outcomes of mandibular reconstruction with DCIA flap using 3-STS or conventional surgical templates. The primary outcome of the study was the accuracy of reconstruction, and the secondary outcomes included surgical time and bone flap ischemia time. Surgery-related parameters and functional outcomes were also recorded and compared.

RESULTS

Forty-four patients (23 in the 3-STS group and 21 in the control group) between 2015 and 2021 were included. Compared with the control group, the 3-STS group had higher accuracy of reconstruction, indicated by lower deviation in absolute distance (1.45 ± 0.76 mm versus 2.02 ± 0.89 mm; P = 0.034), and less deviation in coronal and sagittal angles (0.86 ± 0.53 degree versus 1.27 ± 0.59 degrees, P = 0.039; and 2.52 ± 1.00 degrees versus 3.25 ± 1.25 versus, P = 0.047) between preoperative and postoperative computed tomographic imaging. Surgical time and bone flap ischemia time were significantly reduced in the 3-STS group compared with the control group (median time, 385 minutes versus 445 minutes and 32 minutes versus 53 minutes, respectively; P < 0.001). In addition, masseter attachment was preserved in the 3-STS group but not in the control group. No differences were found in adverse events or other clinical variables.

CONCLUSION

The 3-STS can improve accuracy, simplify intraoperative procedures to increase surgical efficiency, and preserve functionality in mandibular reconstruction for Brown class I defects.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

How Is a Cutting Guide With Additional Anatomical References Better in Fibular-Free Flap Mandibular Reconstruction? A Technical Strategy

BACKGROUND

Computer-assisted surgery is used to design and manufacture cutting guides in mandibular reconstructions with fibula-free flaps. To improve the outcomes of the procedure, the aim of this research was to investigate and compare the accuracy of mandibular reconstruction following the use of 2 versus 3 anatomical reference cutting guides.

METHODS

Eighteen sets of prototype bone models retrieved from an ameloblastoma patient were used for mock operations. The mandibular segmental osteotomies and fibular reconstructions were performed using 2 and 3 anatomical reference cutting guides in vivo surgeries. After reconstruction, the accuracy of the placed reference points was measured by superimposition of computed tomography images.

RESULTS

The error in cutting guides when using 2 or 3 anatomical references showed no significant difference. The fibular and condylar errors of the cutting guide between 2 and 3 anatomical references showed no significant difference in every plate type. The difference in screw hole position errors between 2 and 3 anatomical reference cutting guides was not statistically significant.

CONCLUSIONS

Two anatomical reference cutting guides are sufficient and reasonable enough for mandible resection. However, there were some limitations and errors in our study.

Postoperative facial appearance of patients with extensive oral squamous cell carcinoma can be adequately preserved with in‑house virtually planned mandibular reconstruction

The present study aimed to assess the concordance of preoperative and postoperative hard and soft tissues in patients with advanced oral squamous cell carcinoma (OSCC) following virtual surgical planning (VSP) mandibular reconstruction. In the present study, a cohort of 32 patients with OSCC underwent in-house VSP, followed by guided mandibular reconstruction utilizing vascularized free tissue grafts sourced from the fibula or scapula. A morphometric analysis was conducted comparing preoperative and postoperative three-dimensional virtual models to evaluate discrepancies and identify potential risk factors associated with poor reconstruction outcomes. The outcome variables were the differences in root mean square (RMS) and mean surface distance (MSD) resulting from the application of an iterative closest point algorithm to the virtual data. The validity of soft tissue comparison data is limited due to its susceptibility to various confounding variables. The present study conducted a comprehensive re-evaluation of these variables. High tumor stage, positive N status and the use of adjuvant therapy contributed to more noticeable differences in preoperative and postoperative facial soft tissue appearance. The accuracy of postoperative bone reconstruction results was higher in patients who underwent neomandibular formation using a fibular graft compared with those who received a scapular graft. Preoperative and postoperative soft tissue analyses were conducted for comparison. The MSD showed a deviation of 3.2 mm (± 2.0 mm SD; range 1.3-9.5 mm), whereas the RMS was 5.3 (± 2.9 SD; range 2.1-14). In conclusion, in-house VSP and guided mandibular reconstructions can yield clinically accurate results, preserving patient appearance and offering the advantage of rapid feasibility.

Customed 3D-printed Polyetheretherketone (PEEK) Implant for Secondary Salvage Reconstruction of Mandibular Defects: Case Report and Literature Review

Given the insufficient height of single-barrel fibula and inadequate bone volume of double-barrel vascularized fibula in mandibular reconstruction, it is a better choice to combine the upper full-thickness vascularized fibula with the lower half-thickness nonvascularized fibula. However, the nonvascularized fibula may fail due to complications, affecting the facial shape and occlusal function. Polyetheretherketone is a thermoplastic polymer used for bone defect reconstruction due to its good mechanical properties and biocompatibility. This case report mainly presents a secondary salvage reconstruction of the mandible by using customed 3-dimensional-printing polyetheretherketone, which restored the continuity and symmetry of the mandible, improved the patient's facial shape, and restored functional occlusion through dental implants. After a 28-month follow-up, no complications occurred, and the patient was satisfied with the final restoration.

Osseointegration and Bone Resorption of Scapula Tip Free Flaps in Mandibular Reconstruction

OBJECTIVES

Bone resorption of more conventional vascularized bone grafts have been well described showing minimal resorption over time. Few studies have evaluated osseous union and bone resorption in scapula tip free flaps (STFF) in the reconstruction of mandibulectomy defects. We aimed to describe our series on STFF with respect to osseous union and bone resorption over time.

METHODS

Retrospective chart review of patients receiving STFF from January 2014-January 2017 (n = 25). A neuroradiologist analyzed follow-up CT scans to assess (1) STFF complete, partial, or no osseous union with native mandible and (2) STFF volume change over time in a subset with multiple follow-up scans (n = 18).

RESULTS

Twenty-three of 25 patients (92%) showed complete or partial STFF osseous union with native mandible either distally or proximally. STFF volume change ranged from +4.8 to -54% (median -0.5%) over median follow-up interval of 23 months. History of chemoradiation therapy, bisphophonate use, sex, age, or smoking history did not correlate with bone resorption.

CONCLUSIONS

STFFs shows high rates of osseous union and limited bone resorption that is equivalent to, or less than, vascularized fibular and iliac crest flaps. Clinically, this translates into both optimal healing and functional and cosmetic outcomes, especially in the setting of prior therapies.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2597-2602, 2023.

Patient-specific 3D-printed mini-versus reconstruction plates for free flap fixation at the mandible: Retrospective study of clinical outcomes and complication rates

This study aimed to compare the clinical outcomes and complication rates of patient-specific 3D-printed mini- and reconstruction plates for free flap fixation in mandibular reconstruction. A retrospective monocentric study was carried out between April 2017 and December 2021 to analyze patients undergoing immediate mandibular reconstruction using fibula free flaps and osteosynthesis using patient-specific 3D-printed implants. Eighty-three patients with a mean age of 63.6 years were included. The mean follow-up period was 18.5 months. Patient-specific 3D-printed plates were designed as reconstruction plates (38 patients), miniplates (21 patients) or a combination of reconstruction- and miniplates (24 patients). With miniplates, plate removal was performed significantly more often via an intraoral approach (p < 0.001) and in an outpatient setting (p = 0.002). Univariate analysis showed a higher fistula rate with reconstruction plates (p = 0.037). Multivariate analysis showed no significant differences in complications. Case-control matching demonstrated significantly lower rates of fistula (p = 0.017) and non-union (p = 0.029) in the combined group. This retrospective study shows a tendency towards reduced complication rates with patient-specific 3D-printed miniplates in comparison to patient-specific 3D-printed reconstruction plates for immediate mandibular reconstruction with fibula free flaps.

Planning of physiotherapeutic procedure in patients after mandible reconstruction taking into account donor site: a literature review

BACKGROUND

Mandible tumors are very rare. One of the main methods of the treatments is resection of the tumor and then reconstruction of the mandible. The donor site is often distant tissue-fibula or ilium. Following this, it is necessary to improve the patient in two ways, on one hand restoring the function of the mandible, and on the other hand, improving the donor site area. For that reason, physiotherapy after tumor resection and reconstruction of the mandible is very complicated. The aim of this bibliographic review was to find the methods of the reconstruction of the mandible in the context of patients' functional assessment after surgeries to create effective physiotherapeutic procedures in the feature.

METHODS

PEDro, Medline (PubMed), Cochrane Clinical Trials were searched.

RESULTS

767 articles were found. 40 articles were included to this literature review.

CONCLUSIONS

Authors showed different kinds of surgeries strategy for patients with tumors of the mandible. They also showed manners of patients' functional assessment in the localization of transplantation and donor site. It could be useful for physiotherapists during planning of comprehensive physiotherapy.

Double Arterialized Scapular Tip Free Flap for Mandibular Reconstruction

INTRODUCTION

Scapular tip free flap (STFF) has become today one of the workhorse flaps for maxillary reconstruction; recently, the possibility of extending the vascular supply by adding to the angular branch of the circumflex pedicle up to its periosteal entrance in the lateral border of the scapula has been proposed as a reliable technique to improve the length of perfused bone when STFF is used for mandibular reconstruction. The purpose of this study was to evaluate the patients who had received microvascular reconstruction of the mandible with STFF vascularized by both the circumflex scapular artery via the periosteal branch and the thoracodorsal artery via the angular artery.

METHODS

A retrospective chart review was conducted for all patients who underwent reconstruction with an STFF for mandibular defect between January 2016 and December 2020 at the University Hospital of Parma. The outcome was evaluated by assessing dietary intake (unrestricted, soft, liquid, and tube feed) and speech (normal, intelligible, partially intelligible, and unintelligible).

RESULTS

The final study sample included 9 patients (5 men and 4 women). The average patient age was 68.9 years (range, 59.9-74.8 y) at the time of surgery. There was no flap loss. A 1-year postoperative computed tomography scan revealed full osteointegration of the flap.

CONCLUSIONS

Our results show that the STFF is a valuable reconstructive option, especially in patients with complex head and neck defects requiring soft and hard tissues.

Factors Affecting Complete Oral Rehabilitation in Patients With Vascularized Free Fibula Flap Mandibular Reconstruction: A 10-Year Retrospective Study

The fibula is the preferred bone flap for mandibular reconstructions due to its many advantages, including the possibility to insert dental implants. All patients who received a mandibular reconstruction with a vascularized free fibula flap at the Uppsala University Hospital between 2009 and 2019 were retrospectively examined regarding the proportion of implant insertion and factors that affected implant outcome. Forty-one patients had 42 fibula flap reconstructions. Eleven patients (27%) received dental implants and 8 (20%) completed dental rehabilitation. Patient death and cancer recurrence were the main reasons for not receiving implants. The survival rates of implants placed in irradiated and nonirradiated fibulas were 15% and 76%, respectively. Less than 20% of reconstructed patients received an implant-supported prosthesis. Implants placed in an irradiated fibula should be considered at high risk for implant loss.

Comparing donor site morbidity in osteocutaneous radial forearm versus fibula free flap for mandibular reconstruction

PURPOSE

The osteocutaneous radial forearm free flap has gained popularity as a less morbid option for oromandibular reconstruction compared to the fibular free flap. However, there is a paucity of data regarding direct outcome comparison between these techniques.

METHODS

Retrospective chart review of 94 patients who underwent maxillomandibular reconstruction intervened from July 2012-October 2020 at the University of Arkansas for Medical Sciences. All other bony free flaps were excluded. Endpoints retrieved encompassed demographics, surgical outcomes, perioperative data, and donor site morbidity. Continuous data points were analyzed using independent sample t-Tests. Qualitative data was analyzed using Chi-Square tests to determine significance. Ordinal variables were tested using the Mann-Whitney U test.

RESULTS

The cohort was equally male and female, with a mean age of 62.6 years. There were 21 and 73 patients in the osteocutaneous radial forearm free flap and fibular free flap cohorts, respectively. Excluding age, the groups were otherwise comparable, including tobacco use, and ASA classification. Bony defect (OC-RFFF = 7.9 cm, FFF = 9.4 cm, p = 0.021) and skin paddle (OC-RFFF = 54.6 cm2, FFF = 72.21 cm2, p = 0.045) size were larger in the fibular free flap group. However, no significant difference was found between cohorts with respect to skin graft. There was no statistically significant difference between cohorts regarding the rate of donor site infection, tourniquet time, ischemia time, total operative time, blood transfusion, or length of hospital stay.

CONCLUSIONS

No significant difference in perioperative donor site morbidity was found between patients undergoing fibular forearm free flap and osteocutaneous radial forearm flap for maxillomandibular reconstruction. Osteocutaneous radial forearm flap performance was associated with significantly older age, which may represent a selection bias.

Early Second Free Flap is Required in Osteoradionecrosis-related Nonunion after Primary Mandible Reconstruction

Osteoradionecrosis (ORN) manifested as symptomatic nonunion between primary free flap and native mandible after primary bony reconstruction of the mandible is an entity not included in current conventional ORN staging guidelines. This article reports on and proposes early management of this debilitating condition using a chimeric scapular tip free flap (STFF).

Methods

A retrospective review was performed examining cases with bony nonunion at the junction of primary free fibula flap (FFF) and native mandible at a single center over a 10-year duration, which required a second free bone flap. Details of each case (patient demographics, oncological details, primary surgery, presentation, and secondary surgery) were documented and analyzed. Outcomes of the treatment were assessed.

Results

Four patients (two men and two women; age range, 42-73 years) out of a total of 46 primary FFF were identified. All patients presented with symptoms of low-grade ORN and radiological signs of nonunion. All cases were reconstructed with chimeric STFF. The duration of follow-up ranged from 5 to 20 months. All patients reported resolution of symptoms and radiological evidence of union. Two of four patients subsequently received osseointegrated dental implants.

Conclusions

Institutional rate of nonunion after primary FFF requiring a second free bone flap is 8.7%. All the patients of this cohort presented with a similar clinical entity easily discounted as an infected nonunion postosseous flap reconstruction. There is no ORN grading system that currently guides the management of this cohort. Good outcomes are possible with early surgical intervention with a chimeric STFF.

An Artificial Intelligence-Based Cosmesis Evaluation for Temporomandibular Joint Reconstruction

OBJECTIVE

Management of the temporomandibular joint (TMJ) following condylar resection remains challenging in the field of mandibular reconstruction. A simple reconstruction of the TMJ with a contoured end of a fibular graft placed into the joint space is a potential option, but its efficacy is unknown partly because there are only few objective assessment systems for aesthetic outcome. This study aimed to develop an artificial intelligence (AI)-based aesthetic outcome evaluation system for the simple TMJ reconstruction method and evaluate its functional outcomes.

METHODS

Patients who underwent segmental mandibular resection and reconstruction with fibular flaps at our institution between 2011 and 2020 were retrospectively reviewed. The mandibular asymmetry value was introduced as a primary aesthetic outcome measure, calculated for each patient's photograph using facial recognition AI. The outcomes of the simple TMJ reconstruction method were compared with those of cases in which the native condyle was preserved.

RESULTS

Ten patients underwent condylar resection followed by simple TMJ reconstruction, while the native condyle was preserved in 18 patients. No significant difference was observed in the postoperative mandibular asymmetry value between the two treatment groups. No significant differences were found in the functional outcomes of deglutition and speech.

CONCLUSION

The AI-based asymmetry evaluation system was useful as an aesthetic outcome measure in mandibular reconstruction. Simple TMJ reconstruction with a fibular end seemed to be a promising option, as there were no significant differences in both aesthetic and functional outcomes between this method and those cases in which the native condyle was preserved. Laryngoscope, 133:841-848, 2023.

Time-of-Flight Angiography in Ultra-High-Field 7 T MRI for the Evaluation of Peroneal Perforator Arteries Before Osseomyocutaneous Flap Surgery

OBJECTIVES

Presurgical identification and morphologic characterization of the peroneal perforator arteries (PPAs) are essential for osseomyocutaneous flap surgery. The aim of this study was to evaluate PPAs using time-of-flight (TOF) angiography in 7 T magnetic resonance imaging in comparison with dual-energy computed tomographic angiography (CTA).

MATERIALS AND METHODS

In this prospective study, TOF angiography and CTA of both lower legs were acquired before flap surgery from 07/2019 to 02/2020. Magnetic resonance imaging was performed using a dedicated 28-channel knee coil with an acquisition time of 9:55 minutes (voxel size: 0.4 × 0.4 × 0.8 mm). Computed tomographic angiography was acquired with a third-generation dual-source computed tomography on the same day. Virtual monoenergetic reconstructions at 40 keV photon energy served as the standard of reference for PPA identification and subtyping. Two independent readers assessed the image quality, quantity, length assessment, and classification according to surgical considerations of PPAs for TOF angiography and CTA. Both TOF angiography and CTA were used for presurgical flap design and were evaluated by an orofacial surgeon.

RESULTS

Ten patients (mean age, 59.9 ± 14.9 years; 7 men) were included. Time-of-flight angiography and CTA identified 53 and 51 PPAs in total, respectively. Time-of-flight angiography showed superior image quality (both readers, P < 0.05). Time-of-flight angiography enabled specific classification of PPA subtypes more often (53 vs 39; P < 0.05), and both readers reported higher diagnostic confidence for TOF angiography than CTA in all patients (interrater agreement κ = 0.8; P < 0.05). Regarding length assessment, PPAs were significantly more conspicuous with TOF angiography (TOF mean , 50 ± 11 mm; CTA mean , 40 ± 9 mm; P = 0.001). In comparison with CTA, TOF angiography prospectively changed the orofacial surgeon's final decision on the presurgical selected PPAs in 60% of cases.

CONCLUSIONS

Presurgical assessment of PPAs is feasible using TOF in 7 T magnetic resonance imaging. Moreover, TOF angiography was superior to CTA for classifying and identifying PPAs, which may facilitate the planning of reconstructive surgery.

Functional outcomes following mandibulectomy and fibular free-flap reconstruction

There remains a paucity of evidence with regards to functional outcomes following the reconstruction of segmental defects in the mandible. It is, however, well recognised that oral rehabilitation following head and neck surgery is a driver of improved quality of life outcomes. We present a prospective service review of functional outcomes of a consecutive cohort of patients following segmental mandibulectomy and virtual surgical planning (VSP) composite fibular free-flap reconstruction. Twenty-five patients, who were identified as having a complete dataset with a minimum of 12 months' follow up, ultimately met the inclusion criteria. Validated functional outcome measures were used primarily to assess speech, diet, and swallowing outcomes. The results demonstrate a decline in both speech and swallowing outcomes at three months postoperatively, with a decline of 37% in the Speech Handicap Index from the preoperative baseline, and a decline of 35% in the MD Anderson Dysphagia Inventory score over the same period. The MD Anderson Dysphagia Inventory score improved at 12 months, whereas the Speech Handicap Index did not. Fundamentally a collaborative approach is required between members of the multidisciplinary team (MDT) to enable optimal patient outcomes.

Iliac crest towards alveolar processes or mandibular inferior margin in mandibular reconstruction with a vascularized iliac bone flap: which is better?

OBJECTIVE

The study aims to compare differences among iliac bone flaps with different iliac crest orientations for the repair of mandibular defects with an aim to analyze their advantages, disadvantages, and effects.

MATERIAL AND METHODS

Clinical data and computed tomography scans of all patients who underwent iliac bone flap repair of the mandible in Peking University School and Hospital of Stomatology from January 2016 to April 2021 were collected. Patients were divided into the iliac crest towards alveolar process (Group A) and the iliac crest towards mandibular inferior margin (Group B). Software was used to measure corresponding indicators. The results obtained for the groups were statistically analyzed.

RESULTS

The study included 78 patients (25 and 53 in groups A and B, respectively). The symmetry of the LC-type defect was better in group A (p < 0.05). The all-bone width of the alveolar process side in group A was greater than 6 mm; in 15 cases of group B, the width was less than 6 mm (p < 0.05). The intermaxillary distance of two sites were higher in group B (p < 0.05). The bone cortical thickness was significantly thicker in group A (p < 0.05).

CONCLUSION

One year after the mandibular body defect was reconstructed with a vascularized iliac bone flap, the iliac crest towards alveolar process group showed better bone symmetry, width, intermaxillary distance, and cortical thickness to meet the planting requirements.

CLINICAL RELEVANCE

The use of an iliac crest towards alveolar process may be a better approach for mandible reconstruction.

Towards Optimum Mandibular Reconstruction for Dental Occlusal Rehabilitation: From Preoperative Virtual Surgery to Autogenous Particulate Cancellous Bone and Marrow Graft with Custom-Made Titanium Mesh-A Retrospective Study

The purpose of this retrospective study was to evaluate computer-assisted virtual surgery and the outcomes of mandibular reconstruction using an autogenous particulate cancellous bone and marrow (PCBM) graft combined with a custom-made titanium mesh (TiMesh) using a three-dimensional (3D) printing model. Eighteen consecutive patients were included, and preoperative virtual simulation surgery was performed using digital data. Segmental bone defects showed deviation of the mandible due to displacement of the condyle and segments, unnatural length of the mandibular body, or poorer intermaxillary relationship compared to the marginal bone defect caused by previous operations. These mandibular disharmonies could be simulated, and virtual surgery was performed on a computer with adjustment of displaced mandibular segments, length of the mandibular body, and dental arch with digital bone augmentation. TiMesh was manually pre-bent using a 3D printing model, and PCBM from the iliac crest was grafted with TiMesh. The short-term clinical results were good; reconstruction of the alveolar crest was prosthetically desirable; and minor complications were observed. In conclusion, virtual reconstruction is crucial for treating complex deviated mandibles. Accurate condylar and dental arch positions with an optimum mandibular length are important for prosthetically satisfactory mandibular reconstruction.

Risk factors associated with fixation-related complications in microsurgical free flap reconstruction of the mandible

BACKGROUND

Hardware complications (loosening of screws, infection, or exposure of the plate) in mandibular reconstruction with vascularized osseous free flaps impose significant morbidity, and frequently require revision surgery. Purpose of this study was to identify possible contributing factors for hardware complications.

METHODS

This is a retrospective cohort study involving case series of patients who underwent microvascular mandible reconstructions between 2000 and 2020. Patient demographics, pathological, clinical, and treatment-related factors were analyzed in univariate and multivariate analyses.

RESULTS

Ninety-one patients were enrolled, encompassing 63 reconstructions with fibular free flaps, 26 reconstructions with scapular, and 2 reconstructions with iliac flaps. Rate of hardware complications and plate exposure was 14.3% and 7.7%, respectively, with a median follow-up time for extrusion of 29 months. In univariate analysis, preoperative radiotherapy (odds ratio [OR] = 6.57, p = .01), and secondary mandible reconstruction (OR = 4.3, p = .04) were significant predictors of hardware complications, and plate exposure was most frequently found in secondary reconstruction (37.5%, OR = 11.8, p = .04). Hypertension was the most commonly found comorbidity (24%), and it trended toward significance regarding plate exposure (p = .05). Only secondary mandible reconstruction was associated with osteosynthesis complications (OR = 12.53, p = .01) and plate exposure (OR = 23.86, p = .005) on multivariate analysis, while preoperative radiation therapy did not retain its relevance on plate exposure.

CONCLUSION

Secondary mandible reconstructions with vascularized osseous free flaps have a higher risk of osteosynthesis complications than primary reconstructions.

The Precision of Different Types of Plates Fabricated With a Computer-Aided Design and Manufacturing System in Mandibular Reconstruction With Fibular-Free Flaps

Computer-assisted surgery (CAS) has been introduced to mandible reconstruction with fibular-free flap in cutting guide placement. When CAS cooperates with different plate fixations, the results show various degrees of errors by which this study aimed to evaluate. Mock surgeries were conducted in 3D-printed mandibles with 2 types of defects, limited or extensive, reconstructed from 2 ameloblastoma patients. Three types of fixations, miniplate, manually bending reconstruction plate, and patient-specific plate, are tested, each of which was performed 3 times in each type of defect, adding up to 18 surgeries. One with the least errors was selected and applied to patients whose 3D-printed mandibles were derived. Finally, in vivo errors were compared with the mock. In limited defect, average errors show no statistical significance among all types. In extensive defect, patient-specific plate had a significantly lower average condylar error than manually bending reconstruction plate and miniplate (8.09±2.52 mm vs. 25.49±2.72 and 23.13±13.54 mm, respectively). When patient-specific plate was applied in vivo , the errors were not significantly different from the mock. Patient-specific plates that cooperated with CAS showed the least errors. Nevertheless, manually bent reconstruction plates and miniplates could be applied in limited defects with caution.

An innovative additively manufactured implant for mandibular injuries: Design and preparation processes based on simulation model

Objective: For mandibular injury, how to utilize 3D implants with novel structures to promote the reconstruction of large mandibular bone defect is the major focus of clinical and basic research. This study proposed a novel 3D titanium lattice-like implant for mandibular injuries based on simulation model, which is designed and optimized by a biomechanical/mechanobiological approach, and the working framework for optimal design and preparation processes of the implant has been validated to tailored to specific patient biomechanical, physiological and clinical requirements. Methods: This objective has been achieved by matching and assembling different morphologies of a lattice-like implant mimicking cancellous and cortical bone morphologies and properties, namely, an internal spongy trabecular-like structure that can be filled with bone graft materials and an external grid-like structure that can ensure the mechanical bearing capacity. Finite element analysis has been applied to evaluate the stress/strain distribution of the implant and bone graft materials under physiological loading conditions to determine whether and where the implant needs to be optimized. A topological optimization approach was employed to improve biomechanical and mechanobiological properties by adjusting the overall/local structural design of the implant. Results: The computational results demonstrated that, on average, values of the maximum von-Mises stress in the implant model nodes could be decreased by 43.14% and that the percentage of optimal physiological strains in the bone graft materials can be increased from 35.79 to 93.36% since early regeneration stages. Metal additive manufacturing technology was adopted to prepare the 3D lattice-like implant to verify its feasibility for fabrication. Following the working framework proposed in this study, the well-designed customized implants have both excellent biomechanical and mechanobiological properties, avoiding mechanical failure and providing sufficient biomechanical stimuli to promote new bone regeneration. Conclusion: This study is expected to provide a scientific and feasible clinical strategy for repairing large injuries of mandibular bone defects by offering new insights into design criteria for regenerative implants.

Towards mechanobiologically optimized mandible reconstruction: CAD/CAM miniplates vs. reconstruction plates for fibula free flap fixation: A finite element study

Due to their advantages in applicability, patient-specific (CAD/CAM) reconstruction plates are increasingly used in fibula free flap mandible reconstruction. In addition, recently, CAD/CAM miniplates, with further advantages in postoperative management, have been introduced. However, biomechanical conditions induced by CAD/CAM systems remain partially unknown. This study aimed to evaluate the primary fixation stability of CAD/CAM fixators. For a patient-specific scenario, the biomechanical conditions induced in a one segmental fibula free flap stabilized using either a CAD/CAM reconstruction plate or CAD/CAM miniplates were determined using finite element analysis. The main output parameters were the strains between intersegmental bone surfaces and stresses in the fixation systems due to different biting scenarios. CAD/CAM miniplates resulted in higher mechanical strains in the mesial interosseous gap, whereas CAD/CAM reconstruction plate fixation resulted in higher strains in the distal interosseous gap. For all investigated fixation systems, stresses in the fixation systems were below the material yield stress and thus material failure would not be expected. While the use of CAD/CAM miniplates resulted in strain values considered adequate to promote bone healing in the mesial interosseous gap, in the distal interosseous gap CAD/CAM reconstruction plate fixation might result in more beneficial tissue straining. A mechanical failure of the fixation systems would not be expected.

Myofascial iliac crest flap for reconstruction of combined oral mucosa-mandibular defects: A single-centre experience

BACKGROUND

Deep circumflex iliac artery (DCIA) myofascial iliac crest flap has been used for combined oral mucosa-mandibular defects reconstruction. The bone component of this composite flap can reconstruct the mandible with superior contour match, and the muscle fascia which used for repairing the oral mucosa defect will transform into an oral mucosa-like appearance. To explore its scope of clinical application and how the fascia transformed into oral mucosa will give surgeons flexibility to reconstruct the combined oral mucosa-mandibular defects.

METHODS

A retrospective review of 18 patients who received combined oral mucosa-mandibular defects reconstruction with DCIA myofascial iliac crest flaps from Dec 2016 to Dec 2020 was performed. The characteristics of the mandibular defects and the flaps were recorded. The postoperative dynamic changes of one graft's fascia were observed from serial photographs.

RESULTS

All myofascial iliac crest flaps survived successfully. The bone grafts were from 4.0 to 9.5 cm (mean 7.6 ± 1.5 cm) in length and from 2.0 to 3.5 cm (mean 2.7 ± 0.4 cm) in height. The sizes of fascia were from 13.5 to 48.0 cm² (mean 27.2 ± 9.4 cm²). The grafted fascia firstly changed into a yellow pseudomembrane-like appearance, and then experienced muscle oedema before finally transformed into an oral mucosa-like appearance at about 60 days after operation.

CONCLUSION

Myofascial iliac crest flap is a good option for reconstruction of combined oral mucosa-mandibular defects because of its excellent bone and oral mucosa matches.

Feasibility of Implant Strain Measurement for Assessing Mandible Bone Regeneration

Nonunion is one of the most dreaded complications after operative treatment of mandible fractures or after mandible reconstruction using vascularized and non-vascularized bone grafts. Often diagnosis is made at advanced stage of disease when pain or complications occur. Devices that monitor fracture healing and bone regeneration continuously are therefore urgently needed in the craniomaxillofacial area. One promising approach is the strain measurement of plates. An advanced prototype of an implantable strain measurement device was tested after fixation to a locking mandible reconstruction plate in multiple compression experiments to investigate the potential functionality of strain measurement in the mandibular region. Compression experiments show that strain measurement devices work well under experimental conditions in the mandibular angle and detect plate deformation in a reliable way. For monitoring in the mandibular body, the device used in its current configuration was not suitable. Implant strain measurement of reconstruction plates is a promising methodical approach for permanent monitoring of bone regeneration and fracture healing in the mandible. The method helps to avoid or detect complications at an early point in time after operative treatment.

Effectiveness of Resective Surgery in Complex Ameloblastoma of the Jaws: A Retrospective Multicenter Observational Study

Ameloblastoma is a rare, benign, odontogenic tumor of epithelial origin, characterized by locally aggressive, expansive growth. Treatment is controversial due to the risk of relapse. The aim of this multicenter retrospective study was to evaluate the effectiveness of complete resection in cases of complex ameloblastoma, which is considered at a higher risk of recurrence. Patients who met at least one of these criteria were included: recurrence, soft-tissue involvement, complete erosion of internal/external cortical walls with involvement of the inferior margin of the mandible, and invasion of the maxillary sinus or nasal cavity. Demographic data, tumor site, type of surgery, histological features, and follow-up information were collected for each patient. The cohort included 55 patients with a mean follow-up of 108 ± 66 months. A multivariate logistic model was used to evaluate variables independently associated with relapse. There were six soft-tissue or maxillary sinus relapses, with a recurrence rate of 10.9%. Most of them arose in patients previously treated. The statistical analysis identified the maxillary location as a fundamental relapse risk factor. En bloc resection with large surgical safety margins seemed to be effective in preventing the relapses. However, complete resection was less effective in preventing recurrences in the soft tissues or maxillary sinus.

Benefits of Patient-Specific Reconstruction Plates in Mandibular Reconstruction Surgical Simulation and Resident Education

Poorly contoured mandibular reconstruction plates are associated with postoperative complications. Recently, a technique emerged whereby preoperative patient-specific reconstructive plates (PSRP) are developed in the hopes of eliminating errors in the plate-bending process. This study’s objective is to determine if reconstructions performed with PSRP are more accurate than manually contoured plates. Ten Otolaryngology residents each performed two ex vivo mandibular reconstructions, first using a PSRP followed by a manually contoured plate. Reconstruction time, CT scans, and accuracy measurements were collected. Paired Student’s t-test was performed. There was a significant difference between reconstructions with PSRP and manually contoured plates in: plate-mandible distance (0.39 ± 0.21 vs. 0.75 ± 0.31 mm, p = 0.0128), inter-fibular segment gap (0.90 ± 0.32 vs. 2.24 ± 1.03 mm, p = 0.0095), mandible-fibula gap (1.02 ± 0.39 vs. 2.87 ± 2.38 mm, p = 0.0260), average reconstruction deviation (1.11 ± 0.32 vs. 1.67 ± 0.47 mm, p = 0.0228), mandibular angle width difference (5.13 ± 4.32 vs. 11.79 ± 4.27 mm, p = 0.0221), and reconstruction time (16.67 ± 4.18 vs. 33.78 ± 8.45 min, p = 0.0006). Lower plate-mandible distance has been demonstrated to correlate with decreased plate extrusion rates. Similarly, improved bony apposition promotes bony union. PSRP appears to provide a more accurate scaffold to guide the surgeons in assembling donor bone segments, which could potentially improve patient outcome and reduce surgical time. Additionally, in-house PSRP can serve as a low-cost surgical simulation tool for resident education.

The temporo-mandibular joint: Reconstruction of the condyle post-ablation

Ablative surgery of the mandibular condyle poses a unique reconstructive challenge for many reasons. The condyle and it's relationship to the TMJ is a unique, complex, functional and aesthetically relevant piece of human anatomy. Resection may be required for both malignant and benign pathologies; each posing a differing set of surgical variables. Particularly in neoplastic processes, there must remain a certain degree of peri-operative flexibility with regards to the extent of the resection, and forethought to the requirement for post-operative radiotherapy; both of which further complicate choice of reconstructive option and surgical or prosthetic planning. The cases involved can often concern paediatric patients, and an additional aspect to be considered is that of growth potential. In this piece, we will discuss the indications for ablation and the techniques involved. We will elaborate on the reconstructive challenges specific to reconstructing the condyle in post-ablative cases. We will then describe and analyse the established reconstructive techniques; aiming to provide a balanced view on the advantages and disadvantages. Our focus will include autologous options such as vascularised and non-vascularised free tissue transfer, and the non-autologous options of custom and stock implants. We will also touch on distraction osteogenesis and ramus osteotomies. Lastly we will look to the future and consider possible innovative techniques which may become available to the surgeon.

Long-term Growth, Functional, and Aesthetic Outcomes after Fibula Free Flap Reconstruction for Mandibulectomy Performed in Children

Background:

The long-term outcome of mandible reconstruction when performed in children has not been well documented.

Methods:

This is a retrospective case series of patients who underwent immediate oncologic mandible reconstruction with a fibula free flap at younger than 18 years of age over a 20-year period, by a single surgeon, who had long-term follow-up.

Results:

A total of 10 patients met inclusion criteria. Patient age ranged from 3 years and 8 months to 17 years and 9 months (mean 11 years). The etiology was malignant tumors in seven patients and benign locally aggressive tumors in three patients. All fibula flaps survived. All donor sites were closed primarily. The mean follow-up duration was 10 years and 5 months (range 3–20 years). The mean patient age at follow-up was 21 years and 10 months (range 8 years and 9 months to 30 years and 9 months). All patients achieved a regular diet and normal speech. Final occlusion was normal in seven of 10 patients. The aesthetic outcome, as evaluated by clinical examination, was a symmetric mandible in eight patients (in the other two the aesthetic asymmetry and malocclusion was minor and did not require operative intervention). Dental implants were ultimately placed in three patients. Leg function was normal in eight patients. Achilles lengthening and tendon transfer was required in one patient, and one patient developed ankle pain associated with running.

Conclusion:

Mandible reconstruction in children with the fibula free flap provides excellent aesthetic and functional outcomes that are durable over time.

Mechanical Fatigue Performance of Patient-Specific Polymer Plates in Oncologic Mandible Reconstruction

Mandible defects are conventionally reconstructed using titanium plates. However, titanium causes metallic artifacts which impair radiological imaging. This study aims at evaluating mechanical fatigue of radiolucent fiber-reinforced polyetheretherketone (f-PEEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polyphenylsulfone (PPSU) polymer plates for mandible reconstruction. A total of 30 plates (titanium [n = 6], f-PEEK [n = 6], PEEK [n = 6], PEKK [n = 6], PPSU [n = 6]) were implanted in synthetic mandibulectomized polyurethane mandibles. Servo-pneumatic mechanical testing with cyclic application of 30−300 N at 3 Hz was conducted. Bite forces were 70% on the unresected and 30% on the resected side. Total number of cycles was set to 250,000. Testing was aborted in case of plate or screw failure. Axial load to failure was tested with a speed of 1 mm/s. Kruskal−Wallis and Dunn’s post hoc tests were used. Titanium, f-PEEK, and PEEK showed no failure in fatigue testing and PPSU (p < 0.001) failed against titanium, f-PEEK, PEEK, and PEKK. Titanium allowed the highest load to failure compared to f-PEEK (p = 0.049), PEEK (p = 0.008), PEKK (p < 0.001), and PPSU (p = 0.007). f-PEEK, PEEK, and PEKK withstood expected physiological bite force. Although titanium plates provided the highest fatigue strength, f-PEEK and PEEK plates showed no failure over 250,000 chewing cycles indicating sufficient mechanical strength for mandible reconstruction.

Surgical Navigation in Mandibular Reconstruction: Accuracy Evaluation of an Innovative Protocol

Aim: the purpose of this work is to present an innovative protocol for virtual planning and surgical navigation in post-oncological mandibular reconstruction through fibula free flap. In order to analyze its applicability, an evaluation of accuracy for the surgical protocol has been performed. Methods: 21 patients surgically treated for mandibular neoplasm have been included in the analysis. The Brainlab Vector Vision 3.0^® software for surgical navigation has been used for preoperative surgical planning and intra-operative navigation. A post-operative accuracy evaluation has been performed matching the position of mandibular landmarks between pre-operative and post-operative CT scans. Results: the maximal discrepancy observed was included between −3.4 mm and +3.2 mm, assuming negative values for under correction and positive values for overcorrection. An average grade of accuracy included between 0.06 ± 0.58 mm and 0.43 ± 0.68 mm has been observed for every mandibular landmark examined, except for mandibular angles that showed a mean discrepancy value included between 1.36 ± 1.73 mm and 1.46 ± 1.02 mm when compared to preoperative measurements. Conclusion: a satisfying level of accuracy has been observed in the protocol presented, which appears to be more versatile if compared to closed custom-made systems. The technique described may represent a valid option for selected patients, but it cannot be considered for routine activity because of the complexity of the method, the mobility of the jaw, the necessity of surgical navigator and the long surgical learning curve that is required.

Patient-Specific 3D-Printed Miniplates for Free Flap Fixation at the Mandible: A Feasibility Study

Background

This study was conducted to evaluate the feasibility, clinical outcomes, and accuracy of patient-specific 3D-printed miniplates for mandible reconstruction with fibula free flaps.

Methods

A feasibility study was conducted with 8 patients. Following virtual planning, patient-specific 1.0 mm titanium non-locking miniplates were produced via laser selective melting. 3D-printed cutting and drilling guides were used for segmental mandible resection and flap harvesting. Flap fixation was performed with two 4-hole miniplates and 2.0 mm non-locking screws (screw length 7 mm) for each intersegmental gap. Clinical follow-up was at least 6 months. Preoperative and postoperative CT/cone beam CT data were used for 3D accuracy analysis and evaluation of bone healing. Plate-related complications were monitored clinically.

Results

Patient-specific miniplate fixation of all flaps was successfully conducted (4 mono-segmental, 4 dual-segmental) with high accuracy (3.64 ± 1.18 mm) between the virtual plan and postoperative result. No technical complications were encountered intraoperatively. Osseous union occurred in all intersegmental gaps (1 partial, 18 complete) after 10 ± 2 months. No material fracture, dislocation, or plate exposure was observed.

Conclusions

Based on this pilot observational study including a limited number of patients, free flap fixation for mandibular reconstruction with patient-specific 3D-printed miniplates is feasible and associated with high accuracy, bone healing, and remote soft tissue complications.

Biomechanical analysis of mandibular defect reconstruction based on a new base-fixation system

Buccal titanium plate fixation is a common method for repairing mandibular defects. However, the method presents certain problems: the requirement of a large volume of titanium plate, a large number of fixation screws, a lengthy duration of the surgical operation, and exposure of the fixation plate which easily causes wound infection. In this study, a new base-fixation system was designed. Mandibular reconstruction was performed using the three-dimensional reconstruction package Mimics. In order to compare the newly designed base-fixation system and the common buccal-fixation system, the stress distributions and the displacement distributions of the whole model under two loading conditions were studied, based on the finite element analysis package ANSYS. The safety of the base-fixation titanium plate was evaluated. The results showed that although the maximum stress of the base-fixation titanium plate was higher than that of the buccal-fixation titanium plate, it was still less than the yield strength of titanium. Therefore, under the condition of applying 300 N of vertical occlusal loading, the base-fixation titanium plate displayed superior fixation ability without permanent deformation (and concomitant fixation failure). The results of the fatigue simulation analysis showed that the safety factor of the base-fixation titanium plate in the working state was 3.8 (>1.0), indicating that its fatigue performance met the application requirements. Compared with traditional buccal fixation, the novel base-fixation system has obvious advantages, suggesting its suitability as a new treatment method for clinical mandibular defect reconstruction.

Near-Infrared Fluorescence with Indocyanine Green to Assess Bone Perfusion: A Systematic Review

Background: Adequate perfusion of a bone flap is essential for successful reconstruction of osseous defects. Unfortunately, complications related to inadequate bone perfusion are common. Near-infrared fluorescence (NIRF) imaging enables intraoperative visualization of perfusion. NIRF has been investigated in reconstructive surgery to aid the surgeon in clinical perioperative assessment of soft tissue perfusion. However, little is known on the beneficial use of NIRF to assess bone perfusion. Therefore, the aim of this review was to search for studies evaluating NIRF to assess bone perfusion. Methods: A systematic review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, was performed. Studies up to October 2021 were included. We extracted data regarding the study population, size and design, reported objective fluorescence parameters and the methodology used for fluorescence imaging and processing. Results: Ten articles were included. Studies reported unevenly on the protocol used for NIRF imaging. Five studies reported objective parameters. Absolute and relative perfusion parameters and parameters derived from maximum fluorescence were reported. The clinical significance of these parameters has not been evaluated in humans. Conclusion: The evidence on bone perfusion as measured with NIRF is limited. More clinical studies are required.

Variations of the thoracodorsal axis: application for scapular tip free flap harvesting

PURPOSE

To illustrate variations of the vascular anatomy of the subscapular system highlighting practical implications on surgical access, patient positioning, and strategies to maximize the exposure of vascular pedicle.

METHODS

A retrospective review of patients undergoing reconstruction with a scapular tip free flap over a 2-year period at a tertiary referral center.

RESULTS

Forty patients were included. In 25 (62.5%) cases, the thoracodorsal artery (TD) ended bifurcating into latissimus dorsi (LD) and angular branch (AB), with the serratus artery branch arising from the LD pedicle; this vascular pattern was defined as "LD-dominant." In 10 (25%) cases, the TD bifurcated into LD and AB, with the serratus artery branch arising from the latter vessel, defined as "AB-dominant." Lastly, there was a trifurcation pattern in 5 (12.5%) patients. There was considerable variability in the distal branching pattern. Twenty-two (55%) patients had 2 LD branches; in 11 (27.5%) cases, there was only 1 LD branch, and 7 (17.5%) cases had 3. Thirty-seven patients (92.5%) had 1 AB; in the remaining three cases (7.5%), there were 2. The entry point of AB was located 4.86 cm (mean) ± 0.75 cm from the fibrous tip. The arm positioning and scapular retraction were the key maneuvers to facilitate pedicle exposure and dissection, with the shoulder abducted and scapula retracted away from the body.

CONCLUSION

The subscapular vascular anatomy is highly variable. Knowledge of anatomic variability alongside surgical pearls to harvest STFF could facilitate the introduction of this flap into the toolkit of head and neck reconstructive teams.

Mandibular resection in patients with head and neck cancer: acute and long-term complications after reconstruction

BACKGROUND

The treatment of head and neck cancer is an intensive multimodal treatment that has a great impact on the individual patient.

AIMS/OBJECTIVES

This study aimed to evaluate acute and long-term complications associated with mandibular resections and reconstructions.

MATERIAL AND METHODS

We retrospectively retrieved data on complications and recurrences among patients that underwent mandibular resections and reconstructions for treating oral cavity cancer (n = 190 patients) and osteoradionecrosis (ORN, n = 72). Reconstructions included composite grafts (n = 177), soft tissue flaps (n = 61), or primary closure without any graft (n = 24).

RESULTS

Forty-two patients that underwent reconstructions with composite grafts displayed serious complications (Clavien-Dindo ≥ IIIa). The complication rates were similar between patients treated for oral cavity cancer and patients treated for ORN. Patients that underwent a primary closure without any graft, had a significantly lower risk of complications compared to patients that underwent the other treatments. After hospitalization, 181 patients (69%) had at least one complication.

CONCLUSIONS

A majority of patients undergoing resection and reconstruction due to oral cancer/ORN suffered from postoperative complications regardless of indication, comorbidity status or reconstruction technique. The risk of Clavien-Dindo grade IIIa-V events was significantly lower for patients treated with primary closure without grafts.

SIGNIFICANCE

The results from this study clarifies the importance of in-depth analyse prior to decision of treatment for patients with head and neck cancer.

The combined anterolateral thigh-Partial iliac crest minihybrid free flap for mandibular reconstruction

BACKGROUND AND AIMS

Tumors of the oral cavity often require extensive resections leading to significant hard and soft tissue defects. Microvascular free flaps, consisting of both hard and soft tissue, are often required in reconstructions. Hybrid flaps, composed of two different joint free flaps, offer potential alternatives for head and neck reconstruction. This report presents our results with a modified hybrid ALT/DCIA, that is, minihybrid free flap (MH-flap) composed of the anterolateral thigh (ALT) and a partial inner lamina iliac crest only (partial DCIA) for reconstruction of the mandibular region.

PATIENTS AND METHODS

Eight patients underwent oral cancer reconstruction of the mandible with the MH-flap. The MH-flap was harvested sparing the outer crest and lamina of crista, and its pedicle was combined to the distal pedicle of ALT. Clinical data and postoperative complications were analyzed.

RESULTS

The mean length of the osseous graft was 64 mm (range 54-78 mm). None of the patients had complications requiring surgical intervention. No donor site complications were observed. The overall survival rate was 100%. The mean length of follow-up was 16 months (range 7-30 months).

CONCLUSIONS

According to our results, the ALT-partial DCIA MH-flap has postoperative outcomes comparable to those of the fibular flap. The flap is a good option with excellent bone properties for reconstruction of limited mandibular defects not suitable for fibular or scapular reconstruction.

Reconstruction of the mandibular symphysis: pilot study compares three different flaps

BACKGROUND

Restoration of mandibular continuity, functionality and attempting to return patients to their premorbid state is the ultimate goal of reconstruction. Some studies compare different flaps but the reconstructed portions vary and there is little consensus on the best option for a particular defect.

METHODS

This pilot study compares three different reconstructive options with free flap. We will analyze the accuracy of the reconstruction, the post-operative complications related to the reconstruction, the morbidity of the donor site. This pilot study compares three different reconstructive options with free flap in the reconstruction of the mandibular symphysis: iliac crest, scapula and fibula.

RESULTS

In our sample the morbidity of the donor site was overlapping, as for all three choices free from complications. In post resection edentulous patients, the fibula seems to guarantee better positioning, while in patients with residual occlusion the iliac crest (figure n.4 and n.5) seems to allow a more congruous repositioning. The fibula seems to have a superiority over the other flaps in terms of accuracy in all types of patient.

CONCLUSIONS

Contrary to the most recent work on the accuracy of CAD / CAM, we have analyzed the error in the reconstruction of a specific segment and in the repositioning of the residual mandibular component without the use of guided computer programming.

Skeletal regeneration for segmental bone loss: Vascularised grafts, analogues and surrogates

Massive segmental bone defects (SBD) are mostly treated by removing the fibula and transplanting it complete with blood supply. While revolutionary 50 years ago, this remains the standard treatment. This review considers different strategies to repair SBD and emerging potential replacements for this highly invasive procedure. Prior to the technical breakthrough of microsurgery, researchers in the 1960s and 1970s had begun to make considerable progress in developing non autologous routes to repairing SBD. While the breaktthrough of vascularised bone transplantation solved the immediate problem of a lack of reliable repair strategies, much of their prior work is still relevant today. We challenge the assumption that mimicry is necessary or likely to be successful and instead point to the utility of quite crude (from a materials technology perspective), approaches. Together there are quite compelling indications that the body can regenerate entire bone segments with few or no exogenous factors. This is important, as there is a limit to how expensive a bone repair can be and still be widely available to all patients since cost restraints within healthcare systems are not likely to diminish in the near future. STATEMENT OF SIGNIFICANCE: This review is significant because it is a multidisciplinary view of several surgeons and scientists as to what is driving improvement in segmental bone defect repair, why many approaches to date have not succeeded and why some quite basic approaches can be as effective as they are. While there are many reviews of the literature of grafting and bone repair the relative lack of substantial improvement and slow rate of progress in clinical translation is often overlooked and we seek to challenge the reader to consider the issue more broadly.

Surgical Free Flaps and Grafts in Head and Neck Reconstruction: Principles and Postoperative Imaging

This review article discusses the basic principles behind the use of flaps and grafts for reconstructive surgery in the head and neck, with a special emphasis on the types of commonly used free flaps, their imaging appearance as well as some frequently encountered postoperative complications. Given the ubiquity and complexity of these reconstructive techniques, it is essential that head and neck radiologists be familiar in distinguishing between the expected evolving findings, complications, and tumor recurrence.

Complications in oncologic mandible reconstruction: A comparative study between the osteocutaneous radial forearm and fibula free flap

BACKGROUND

The osteocutaneous radial forearm free flap (OC-RFFF) has been proposed as a safe and reliable free flap for head and neck reconstruction with low donor site morbidity. The purpose of this study is to compare the late complications (>30 days) associated with using the OC-RFFF versus the free fibula flap (FFF) for mandibular reconstruction following oncologic segmental resection.

METHODS

We conducted a single-institution, retrospective study composed of patients who underwent oncologic microvascular composite mandibular reconstruction with either the OC-RFFF or FFF. The primary predictor variable was the type of free flap used. The outcome variable was late complication postoperatively (>30 days).

RESULTS

A total of 93 patients (28, OC-RFFF and 65, FFF) were analyzed. The majority of patients were male (62%) and with AJCC stage T4a disease (72%). Mean hospital length of stay was comparable between the two flap groups (p = .50). OC-RFFF was associated with more late complications (p = .03) compared to FFF. Nonunion occurred in 10.7% of OC-RFFF and 0% of FFF. Partial or complete flap failure was seen in 7.1% and 0% in the OC-RFFF and FFF, respectively. Two-year disease-free survival was comparable in both groups (p > .05).

CONCLUSIONS

The results of this study suggest that the rate of nonunion and odds of having a late complication were significantly greater in the OC-RFFF compared to the FFF following oncologic mandibular reconstruction. However, flap success, early complications (<30 days), and length of hospital stay were comparable between the two flaps.