Microvascular Bone Flaps Research Articles

Accuracy of the surgical execution of virtually planned deep circumflex iliac artery flaps and their appropriateness for masticatory rehabilitation

BackgroundTumorous diseases of the jaw demand effective treatments, often involving continuity resection of the jaw. Reconstruction via microvascular bone flaps, like deep circumflex iliac artery flaps (DCIA), is standard. Computer aided planning (CAD) enhances accuracy in reconstruction using patient-specific CT images to create three-dimensional (3D) models. Data on the accuracy of CAD-planned DCIA flaps is scarce. Moreover, the data on accuracy should be combined with data on the exact positioning of the implants for well-fitting dental prosthetics. This study focuses on CAD-planned DCIA flaps accuracy and proper positioning for prosthetic rehabilitation.MethodsPatients post-mandible resection with CAD-planned DCIA flap reconstruction were evaluated. Postoperative radiograph-derived 3D models were aligned with 3D models from the CAD plans for osteotomy position, angle, and flap volume comparison. To evaluate the DCIA flap’s suitability for prosthetic dental rehabilitation, a plane was created in the support zone and crestal in the middle of the DCIA flap. The lower jaw was rotated to close the mouth and the distance between the two planes was measured.Results20 patients (12 males, 8 females) were included. Mean defect size was 73.28 ± 4.87 mm; 11 L defects, 9 LC defects. Planned vs. actual DCIA transplant volume difference was 3.814 ± 3.856 cm³ (p = 0.2223). The deviation from the planned angle was significantly larger at the dorsal osteotomy than at the ventral (p = 0.035). Linear differences between the planned DCIA transplant and the actual DCIA transplant were 1.294 ± 1.197 mm for the ventral osteotomy and 2.680 ± 3.449 mm for the dorsal (p = 0.1078). The difference between the dental axis and the middle of the DCIA transplant ranged from 0.2 mm to 14.8 mm. The mean lateral difference was 2.695 ± 3.667 mm in the region of the first premolar.ConclusionThe CAD-planned DCIA flap is a solution for reconstructing the mandible. CAD planning results in an accurate reconstruction enabling dental implant placement and dental prosthetics.

Antiresorptive agents enhance ossification of free flap reconstructions of the mandible: a radiological retrospective cohort study.

The aim of this study was to investigate the effect of antiresorptive agents on the ossification of reconstructed mandibles by free bone grafts for the first time. A total of 38 reconstructions of the jaw were retrospectively evaluated for ossification between bone segments by two raters based on postoperative panoramic radiographs. The study group (n = 13) had segmental resection of the mandible and free bone flap reconstruction due to medication-related osteonecrosis of the jaw (MRONJ). The control group (noMRONJ, n = 25) comprised segmental mandibular resections and free bone flap reconstructions due to tumors, chronic osteomyelitis, or trauma without any radiation. Ossification time and influencing factors were evaluated. Both duration of surgery (346 ± 90min. vs. 498 ± 124min.; p < 0.001) and hospitalization (8.7 ± 2.8 days vs. 13.4 ± 5.3 days, p = 0.006) were shorter in the MRONJ group compared to the noMRONJ group. Ossification after mandibular reconstruction was significantly faster in the MRONJ study group [224 days, interquartile range (IQR) 175-287] compared to the control group (288 days, IQR 194-445; p < 0.001). Moreover, good initial contact between the segments resulted in faster ossification (p < 0.001) in the MRONJ group. Ossification rate between original and grafted bone or between grafted bone segments only did not differ in both the study and control groups (MRONJ, p = 0.705 vs. control, p = 0.292). The type of antiresorptive agent did not show any significance for ossification. The rate of wound healing disturbances did also not differ between the study and control groups (p = 0.69). Advanced MRONJ (stage 3) can be resected and reconstructed safely with free microvascular bone flaps. Antiresorptive agents enhance the ossification of the bone segments. Optimal initial contact of the bone segments accelerates bone healing. Surgery and hospitalization are markedly shortened in this vulnerable group of MRONJ patients compared to oncologic patients.

Biomechanical considerations of semi-anatomic glass fiber-reinforced (GFRC) composite implant for mandibular segmental defects: A technical note

ObjectivesThe aim of this study was to investigate the selected biomechanical properties of semi-anatomic implant plate made of biostable glass fiber-reinforced composite (GFRC) for mandibular reconstruction. Two versions of GFRC plates were tested in vitro loading conditions of a mandible segmental defect model, for determining the level of mechanical stress at the location of fixation screws, and in the body of the plate. MethodsGFRC of bidirectional S3-glass fiber weaves with dimethacrylate resin matrix were used to fabricate semi-anatomic reconstruction plates of two GFRC laminate thicknesses. Lateral surface of the plate followed the contour of the resected part of the bone, and the medial surface was concave allowing for placement of a microvascular bone flap in the next stages of the research. Plates were fixed with screws to a plastic model of the mandible with a large segmental defect in the premolar-molar region. The mandible-plate system was loaded from incisal and molar locations with loads of 10, 50, and 100 N and stress (microstrain, με) at the location of fixation screws and the body of the plate was measured by strain gauges. In total the test set-up had four areas for measuring the stress of the plate. ResultsNo signs of fractures or buckling failures of the plates were found during loading. Strain values at the region of the fixation screws were higher with thick plate, whereas thin plates demonstrated higher strain at the body of the plate. Vertical displacement of the mandible-plate system was proportional to the loading force and was higher with incisal than molar loading locations but no difference was found between thin and thick plates. ConclusionGFRC plates withstood the loading conditions up to 100 N even when loaded incisally. Thick plates concentrated the stress to the ramus mandibulae region of the fixation screws whereas the thin plates showed stress concentration in the angulus mandibulae region of the fixation and the plate itself. In general, thin plates caused a lower magnitude of stress to the fixation screw areas than thick plates, suggesting absorption of the loading energy to the body of the plate.

Long-term stability of jaw reconstruction with microvascular bone flaps: A prospective longitudinal study

ObjectivesMicrovascular bone flap jaw reconstruction has achieved satisfactory clinical outcomes. However, little is known about the long-term stability of the reconstructed jaw. This prospective longitudinal study aimed to investigate the long-term stability of jaw reconstruction and factors that were associated with it. MethodsPatients with successful computer-assisted osseous free-flap jaw reconstruction in the Department of Oral and Maxillofacial Surgery, Queen Mary Hospital, Hong Kong were recruited for this prospective longitudinal study. The three-dimensional jaw models at the pre-operative plan, post-operative 1-month, and 2 years were aligned and compared. ResultsA total of 69 patients were recruited, among which 48 patients were available for the long-term analysis. Compared to 1-month after surgery, further deviation from the pre-operative plan was observed at post-operative 2 years. Lack of accuracy in surgery, segmental mandible resection especially with the involvement of mandible angles, and post-operative radiation therapy were identified as the significant factors affecting the positional stability of the reconstructed jaw (p < 0.05). Stable reconstruction was observed in the subgroup analysis of patients without post-operative radiation therapy. ConclusionUp to the best of our knowledge, this is the first prospective longitudinal study reporting the long-term stability of jaw reconstruction and its affecting factors. Our data demonstrated that the reconstructed jaw position lacked stability over the postoperative period. How to improve long-term stability of reconstructed jaw thus optimize the functional outcomes warrants further studies.

Mandibular reconstruction in head and neck cancer: which is the gold standard?

The aim of this study is to perform a systematic review to compare the outcomes of the different surgical options for mandibular reconstruction in head and neck cancer. 93 articles were selected. Four groups were identified: titanium plate without flaps, titanium plate covered by soft tissue flap, bone tissue flaps and double flaps. We compared patients' characteristics, site of mandibulectomy, type of reconstruction and complications. 4697 patients were reported. The groups were not homogeneous regarding the type of defect and the treatment history. A significant difference in terms of post-operative complications was found between group 1 and group 2 (p < 0.00001), and between group 2 and group 3 (p < 0.00001). Total complications rate for group 4 was significantly higher when compared to group 3 (p < 0.00001), but no significant difference was found with group 2. These results suggest that mandibular reconstruction using a microvascular bone flap is the best surgical option in patients without significant comorbidities.

Patient Specific Alloplastic Implant Reconstruction of Mandibular Defects-Safe Practice Recommendations and Guidelines.

Mandibular continuity defects are commonly seen after tumor resection, osteomyelitis or maxillofacial trauma. Three-dimensional reconstruction of these mandibular segmental defects is critical for proper mandibular functioning and esthetics. Various methods used to reconstruct such defects include bridging reconstruction plates, modular endoprosthesis, non-vascularized and vascularized bone grafting with stock reconstruction plate or patient specific implants (PSI) and tissue engineering bone transfer. But in the recent years, literature documents use of PSI only alloplastic reconstruction as an alternate to microvascular bone flap reconstruction. Representative cases enumerate current practice of 'patient specific implant only' mandibular reconstruction and its pitfalls. This article discusses current status of literature on PSI's, choice of indications for 'PSI only' mandibular reconstruction and also proposes guidelines for safe practice of patient specific implant reconstruction of mandible.

Free microvascular bone flaps used for cavity reconstruction in the head and neck area.

The authors would like to present the possibilities of reconstructive surgery using free microvascular flaps with bone elements in the treatment of cavities in the head and neck area. The cavities in the presented article resulted both from resection of tumors in the head and neck area as well as congenital defects and radiation damage. The authors would like to discuss the difficulties that may arise during the postoperative period, including the maintenance of the graft&apos;s viability, the healing of the donor site and systemic problems. The article presents 33 reconstruction surgeries performed on 31 patients using different flaps, briefly describing their advantages and technical difficulties that may arise during the microvascular anastomoses. The authors emphasise the importance of a well-conducted qualification for the surgery as well as the need to discuss the course of the surgery and recovery and other possible treatment options with patients and their families. The complications that happened in the presented group and how they were treated are described. The authors discuss in details the 3 cases with different types of reconstructive procedures and draw attention to the importance of postoperative care consisting of the constant monitoring of the viability of the graft carried out by qualified personnel of the Otolaryngology Department and appropriately conducted anticoagulant therapy.

ASA score and procedure type predict complications and costs in maxillofacial reconstructive surgery: a retrospective study using a hospital administrative database.

Reconstruction of osseous and soft tissue defects after surgical resection of oral cavity cancers can be achieved by a single-stage procedure with a microvascular bone flap or by a two-step approach with a soft tissue flap and subsequent bone augmentation. The therapeutic approach should be selected based on the patient&rsquo;s needs. Economic pressure requires preoperative risk assessment and estimation of the postoperative course. Flat-rate reimbursement systems via diagnosis-related groups with insufficient morbidity adjustments and financial sanction of medical complications might additionally cause false incentives in the choice of treatment. This study aimed to assess the influence of the type of flap chosen for maxillofacial reconstructive surgery on the total costs. Complication rates of different types of flap surgery and their prediction by a preoperative risk assessment tool (American Society of Anesthesiologists [ASA] score) were determined. Overall, the fairness of the current reimbursement system was rated. Patient characteristics, clinical data, and data on total costs and reimbursement of patients aged 18 years and older having undergone maxillofacial reconstructive flap surgery at the University Hospital of Zurich (Switzerland) between 2012 and 2014 were analysed. The preoperative risk was classified by the ASA score. Complications were graded according to the Clavien-Dindo classification system and the comprehensive complication index (CCI). Statistical analysis included Spearman and Pearson rank correlation, Kruskal-Wallis and Mann-Whitney nonparametric tests, and linear regression analysis. 129 patients were included in this study. Soft tissue flaps were performed in 82 patients, of which 56 were radial forearm flaps (43.4%), bone flaps in 41 patients, of which 32 were fibula flaps (24.8%), and combined flaps in 6 patients (4.7%). Patients with fibula flaps showed a significantly higher CCI and higher total costs. Higher preoperative ASA scores were significantly associated with increased length of stay, total costs and complications. Both the ASA score and reconstruction with a radial forearm flap were significant predictors of complications and total costs. Total median costs for radial forearm flaps were CHF 50,560 (reimbursement: CHF 60,851; difference: CHF 10,291) and for fibula flaps CHF 66,982 (reimbursement: CHF 58,218; difference: CHF &minus;8,764). The ASA score allows a reliable preoperative assessment of patient outcomes and financial burden in maxillofacial reconstructive flap surgery. The type of flap reconstruction significantly influences complications and ultimately total costs. The current reimbursement system via diagnosis-related groups (DRGs) does not take sufficient account of this fact. Adaptations are therefore needed to prevent misplaced incentives to the detriment of patients.

Hyperbaric Oxygen Therapy in the Management of Zygomatic Bone Osteomyelitis.

Zygomatic bone osteomyelitis is a rare condition having an incidence of 1.42%. Zygomatic osteomyelitis can be due to haematogenous infection with tubercle bacillus, facial bone fractures or very rarely due to an unknown aetiology like in our case. If surgically managed alone, it would lead to complete loss of zygomatic bone, causing high morbidity to the patient in terms of function and aesthetics like loss of globe support causing dystopia, loss of facial projection causing facial asymmetry. Restoration of facial symmetry and globe support would require extensive procedures such as non-vascular bone grafting or patient-specific implant placement or microvascular bone flap transfer. Hyperbaric oxygen therapy (HBOT) was used to try and preserve the zygoma by promoting revascularisation. The patient received 100% oxygen at 2.5 absolute atmospheric pressure for 90 min, one session per day for 5 days in a week using a mask system in a multiplace chamber. The patient was reviewed clinically and radiologically after each 5 dives of HBOT sessions. After a total of 30 dives of HBOT, CT examination was repeated. There was partial reconstitution of cortical bone without any additional residual bone lesion. Minimal residual sequestra were noted. At this stage, the patient underwent conservative sequestrectomy in contrast to extensive surgery if HBOT was not contemplated. HBOT has the potential to be a very useful adjunct in the treatment of osteomyelitis in head and neck surgery; however, there is a need for carefully designed trials, avoiding methodological bias due to the great variability of patients, infectious agents, antibiotic resistance, host factors, to broaden the evidence of this therapeutic modality.

Outcomes of microvascular bone flaps versus osteocutaneous flaps in head and neck reconstruction.

Surgical resection of head and neck (H&N) neoplasms requiring osseous reconstruction have underdefined complication profiles. This study aimed to characterize postoperative outcomes of patients with H&N neoplasia undergoing osteocutaneous flap (OCF) or bare bone flap (BBF) reconstructions. Retrospective analysis of the National Surgical Quality Improvement Program (NSQIP) 2005-2017 databases. Queried for diagnosis and procedural codes extracted patients with H&N neoplasms undergoing BBF or OCF reconstruction. Postoperative complications were evaluated. Multivariable regression generated adjusted odds ratios. A cohort of 746 patients were identified. Of reconstructions, 24.9% (n = 186/746) were BBFs while 75.1% (n = 560/746) were OCFs. 58.1% of the BBF cohort and 59.9% of the OCF cohort experienced an all-cause complication (p = .654). Sub-stratified, 24.2% of BBF and 17.5% of OCF patients experienced a wound complication (p = .045). Regression analysis demonstrated no difference in risk for medical complications between cohorts. However, patients receiving OCFs had a decreased likelihood of developing a wound complication (OR 0.652; 95%CI 0.430-0.989; p = .044) compared to patients receiving BBFs. The incidence of complications following osseous reconstruction of the H&N is considerable. Although several complication outcomes do not seem to differ between BBF or OCF reconstructions, OCFs is associated with a decreased likelihood of wound complications.

Evaluation of a novel osteosynthesis plate system for mandibular defects

Continuity defects of the jaw can be reconstructed with titanium plates or microvascular bone flaps; osteosynthesis plates are necessary for both. In this study we performed a retrospective review of patients treated with Medartis MODUS® Mandible Trauma/Reco 2.0-2.5, TriLock bridging plates, mandibulectomy and soft tissue free flap or reconstruction with a bony free flap and TriLock mandibular plates from the same system from January 2015 to August 2019. The variables recorded were sex, age, diagnosis, radiotherapy, date of implantation, date of explantation or death of patient, size of mandibular defect, Jewer classification of defect, number of screws used, segments of bony reconstruction, screws per segment, plate exposure, plate breakage, and pseudarthrosis. The bridging plate group consisted of 41 patients, while the mandibular plate group consisted of 24 patients. The percentage of plate exposure was 17.07% for the bridging plate group and 4.17% for the mandibular plate group. Plate breakage was 0 in both groups. Pseudarthrosis was 4.17% in the mandibular plate group. In the bridging plate group, an anterolateral thigh flap covered all exposures. Of 7 plate exposures, 4 were found in a C defect. The complication rate of the investigated plates was lower than the complication rates of other plate systems.

Microvascular reconstruction and dental rehabilitation of benign severely atrophic jaws and defects of the alveolar ridge: our philosophy in 2019

We deal regularly with patients who present with severe atrophy of the jaws, compromised soft tissue, or penetrating defects of the alveolar ridge that are not the result of malignant disease. For these patients we use microvascular bony flaps together with dental implants and implant-supported prostheses. The purpose of this retrospective study was to present our current management and the lessons we have learned over a 16-year period while treating 86 patients for these indications with 87 microvascular bone flaps. We used a transoral approach for the anastomosis in 60 flaps, thereby avoiding visible scars, and inserted 281 dental implants to support fixed or removable dental prostheses. Two femoral flaps developed partial necrosis, and seven implants were lost. Eighty-five of the 86 patients were satisfied with the improvement in their orofacial function and aesthetics. Poor oral hygiene, active osteomyelitis, and severe bruxism are absolute contraindications.

Surgeon-Based 3D Printing for Microvascular Bone Flaps

Background Three-dimensional (3D) printing has developed as a revolutionary technology with the capacity to design accurate physical models in preoperative planning. We present our experience in surgeon-based design of 3D models, using home 3D software and printing technology for use as an adjunct in vascularized bone transfer. Methods Home 3D printing techniques were used in the design and execution of vascularized bone flap transfers to the upper extremity. Open source imaging software was used to convert preoperative computed tomography scans and create 3D models. These were printed in the surgeon's office as 3D models for the planned reconstruction. Vascularized bone flaps were designed intraoperatively based on the 3D printed models. Results Three-dimensional models were created for intraoperative use in vascularized bone flaps, including (1) medial femoral trochlea (MFT) flap for scaphoid avascular necrosis and nonunion, (2) MFT flap for lunate avascular necrosis and nonunion, (3) medial femoral condyle (MFC) flap for wrist arthrodesis, and (4) free fibula osteocutaneous flap for distal radius septic nonunion. Templates based on the 3D models allowed for the precise and rapid contouring of well-vascularized bone flaps in situ, prior to ligating the donor pedicle. Conclusions Surgeon-based 3D printing is a feasible, innovative technology that allows for the precise and rapid contouring of models that can be created in various configurations for pre- and intraoperative planning. The technology is easy to use, convenient, and highly economical as compared with traditional send-out manufacturing. Surgeon-based 3D printing is a useful adjunct in vascularized bone transfer. Level of Evidence Level IV.

A long-term evaluation of the maintenance of vertical height in scapular microvascular bone flaps for mandibular reconstruction

A long-term evaluation of the maintenance of vertical height in scapular microvascular bone flaps for mandibular reconstruction

Bisphosphonate related osteonecrosis of the jaw – Manifestation in a microvascular iliac bone flap

Bisphosphonate related osteonecrosis of the jaw (BRONJ) is a side effect that may emerge due to a long-term bisphosphonate therapy. Although the timely diagnosis and initiation of treatment are associated with good outcome results, extended cases require whole parts of the jaw to be resected. A possible treatment option is the bony reconstruction of the jaw using microvascular bone flaps. We report, for the first time, the development of a bisphosphonate related osteonecrosis in a microvascular iliac bone graft, a reconstruction that was performed following a partial mandibulectomy due to BRONJ stage III. The observation of BRONJ manifestation in an osseous microvascular transplant is a novel finding that sheds new light on current pathogenesis theories that surround this entity. Furthermore, it is hypothesized that BRONJ is able to progress to adjacent bone. In addition, bone reconstruction in patients suffering from BRONJ may be seen more critically.

Future: Tissue Engineering (Regenerative Medicine); Mandible

In benign situations there is a choice of therapeutical options including free bone grafts and tissue engineering techiques. However, for malignancies and especially for irradiated patients with large mandibular defects the clinical options are almost exclusively limited to microvascular bone flaps. However, reconstruction of the mandible with free bone flaps has two limitations. 1) The shape of the bone does not match exactly the requirements. 2) Limited availability/morbidity of donor sites.

An intraoral anastomosing technique for microvascular bone flaps in alveolar ridge reconstruction

The main indication for microvascular reconstruction of the face is to achieve the best possible functional and aesthetic outcome. In several cases of reconstruction of the alveolar ridges of the mandible or maxilla, extraoral scars might have been avoided if microvascular anastomoses had been performed without using the extraoral approach. In 9 patients with severe defects of the alveolar ridge of the mandible or maxilla caused by trauma, tumour resection, atrophy or partial loss of premaxilla, reconstruction was performed using six microvascular corticocancellous femur flaps, two iliac crest flaps and one osteoperiosteal fibula flap. In every case, an intraoral approach was used to prepare the transplant bed and the facial vessels. The anastomoses were carried out via this intraoral approach between the donor vessels and the facial vessels. The patients were followed up radiologically and clinically for 6-24 months postoperatively. There was no flap loss or severe complication postoperatively. All patients had good functional and aesthetic results, were treated successfully with dental implants 4-6 months after microvascular reconstruction, and were subsequently fitted with implant-retained prostheses. Intraoral anastomosing of microvascular bone flaps is a reliable technique for microvascular reconstruction of the alveolar ridge. Extraoral scars can be avoided.

Neue Rekonstruktionsmöglichkeiten von ausgedehnten Kieferdefekten mit vorbereiteten mikrovaskulären Fibulatransplantaten und ITI-Implantaten

The reconstruction of extensive jaw defects is frequently only possible with microvascular bone flaps. Here we are presenting an operative technique using prefabricated fibular flaps and osseointegrated implants. In a first operation, the fibula is prepared with implants, split skin graft, and a nonresorbable membrane. The jaw defect is reconstructed 6 weeks later and can be treated directly with a prosthesis thanks to osseointegrated implants. The technique is described with reference to 5 patients already operated according to this technique and the initial findings are evaluated.

Functional results of dental restoration with osseointegrated implants after mandible reconstruction.

We reviewed the cases of 20 cancer patients (mean age 47.4 years) in whom osseointegrated implants were used for dental restoration after mandibular reconstruction between January of 1988 and December of 1994. Seventy-one implants were placed into bone flaps (n = 60) or native mandible (n = 11), an average of 3.55 per patient (range, 2 to 5). Successful integration occurred in 91.5 percent (65 of 71); there were five early failures and one late failure, with no significant difference between the number lost in microvascular flaps (5 of 60) and native mandible (1 of 11) (as determined by Fisher's exact test). Functional evaluation included assessments of diet, speech, and cosmesis. Based on our review, we concluded that (1) implants enhance dental restoration in selected patients, and (2) microvascular bone flaps, including the fibula and iliac crest, are well suited for dental implant restoration.