Secondary Mandibular Reconstruction Research Articles

Developing A Temporary External Fixator (TEF) for Mandibular Reconstruction using Two-Phase QFD and TRIZ Approach

A temporary external fixator (TEF) is a device used to bridge resection defects after sequestrectomy and before secondary mandibular reconstruction surgery. A well-designed TEF should be customizable and adjustable to accommodate individual patient needs. This study developed a TEF for mandibular reconstruction using the quality function deployment (QFD) and the theory of inventive problem-solving (TRIZ). Customer needs (CNs) were investigated from literature reviews and a survey. Subsequently, a questionnaire was developed, refined, and delivered to 22 experts to identify the essential principles of TEF. Afterwards, the QFD priorities were analyzed based on the acquired CNs and technical requirements (TRs), and the top priorities were found to be safety and adequate operational space. The guidelines for developing a TEF with TRIZ were established as follows: First, using carbon fiber epoxy composite and Ti-6Al-4V as the material for TEFs is recommended Second, permanent magnet should be inserted into the clamp lock bolts to prevent them from falling off during surgery. Last, replacing one Schanz screw with three Bicortical screws is recommended for the fixator pins. Additionally, it was also found that changing the screw size from 2.5–4.0 mm to 2.0–2.4 mm could reduce hole defects in the mandible.

A Novel Method for Secondary Mandible Reconstruction to Re-Achieve a Native Condyle Position Comprising a New Design for Cutting Guides and New Positioning Devices.

Secondary mandibular reconstruction using fibular free flaps (FFF) is a technical challenge for surgeons. Appropriate operation planning is crucial for postoperative quality control and is notably necessary for the (re-) achievement of a physiological condylar position, and the sensible expansion and shaping of the transplant. Computer-assisted planning may help to reconstruct mandibular defects in a patient-specific and precise manner. Herein, we present a newly-developed workflow for secondary mandibular reconstruction using FFF; it comprises digital planning and in-house manufacturing to perform precise secondary mandible reconstruction. This method utilizes a newly designed positioning device to ensure the precise positioning of the fibula segments in relation to each other and the mandibular stumps. The presented in-house-printed positioning device made it possible to achieve digital planning with high precision during surgery.

Controlling and Stabilising Mandible During Reconstruction: Significance and Techniques.

Stable and accurate positioning of condyle in the glenoid fossa is necessary for maintaining occlusion, facial symmetry and normal function of the temporomandibular joint following segmental resection of mandible. In non-reconstructed mandibular segments or those with fractured reconstruction plates the bony defect gets altered due to contraction or inadvertent muscular pull. This paper describes various techniques used to control dentate and edentate segments of the mandible during reconstruction following an ablative procedure. Secondary mandibular reconstruction has always been a tedious task for the surgeons. Several techniques have been described in literature ranging the use of external fixators, gunning splints and dentures for stabilising mandibular segments. Use of a pre-bent and adapted reconstruction plate is a common practice but may not be feasible in malignancies, benign tumours causing expansion and secondary reconstruction. The current advances in virtual surgical planning allows mandibular reconstruction to be performed in a simpler yet predictable manner. The paper describes techniques ranging from twin K-wire placement to occlusal wafers, 3D printed splints and patient specific implants to enable accurate positioning of the segments and achieve pre-operative form. Advances in virtual surgical planning will continue to allow this field to evolve and to improve the quality of life of the patients.

Virtual planning and 3D-printed guides for mandibular reconstruction: Factors impacting accuracy.

Examine accuracy and factors impacting accuracy for mandibular reconstruction with virtual surgical planning, 3D printed osteotomy guides and preoperatively bent mandibular reconstruction plate (VSP/3Dprinted-guide/plate). Retrospective review of osseous-free-flap mandibular reconstructions with VSP/3Dprinted-guide/plate between January 2015 and July 2020 at a single academic medical center.Patient demographics, disease, and treatment variables were extracted. Accuracy was assessed by 3D-model-overlay with cephalometric and donor-bone segment length measurements. Multivariate analyses were performed to determine factors impacting cephalometric accuracy. 60 cases met criteria: 41 (68%) cancer, 14 (23%) osteoradionecrosis (ORN), 5 (8%) secondary mandibular reconstruction. Thirteen cases (22%) were Brown class III or IV. Thirty-nine cases (65%) had ≥2 flap bone segments. Average donor-bone length was 82 mm (SD: 28). 3D-model-overlay accuracy demonstrated minimal deviation between planned and actual reconstruction: intercondylar distance=2.10 mm (SD: 2.2); intergonial distance=2.23 mm (SD: 1.9); anterior-posterior distance (APD)=1.76 mm (SD: 1.5); gonial angle (GA)=3.11 degrees (SD: 2.4). Mean change in donor-bone segment length inferiorly was 2.67 mm (SD: 2.6) and superiorly 3.27 mm (SD: 3.2). Higher number of donor-bone segments was associated with decreased accuracy in GA (p= .023) and longer donor-bone length was associated with decreased accuracy in APD (p= .031). To our knowledge this is the largest series assessing surgical accuracy of VSP/3Dprinted-guide/plate for osseous-free-flap mandibular reconstruction. We demonstrate highly accurate results, with increased number of donor-bone segments and donor-bone length associated with decreased accuracy. Our findings further support VSP/3Dprinted-guide/plate as a reliable and accurate tool for mandibular reconstruction. Level 4.

Secondary Mandible Reconstruction with Computer-Assisted-Surgical Simulation and Patient-Specific Pre-Bent Plates: The Algorithm of Virtual Planning and Limitations Revisited

Despite the known advantages of virtual surgical planning and three-dimensional (3D) printing, translation of virtual planning to actual operation is a challenge, especially in secondary mandibular reconstruction. Patients who underwent secondary microvascular mandibular reconstruction were retrospectively reviewed and categorized into three categories as follows: (i) defect not crossing the midline (category I); (ii) defects crossing the midline with availability of previous imaging data (category II) and; (iii) defects crossing the midline with unavailability of previous imaging data (category III). The resulting 3D printed models were used as an effective guide for plate bending during secondary reconstruction surgery. Accuracy of the reconstruction was evaluated by superimposing post-operative images over virtual plan. Out of eleven patients, five were category I, three were category II, and three were category III. The mean linear discrepancy between the planned and post-operative position was measured. A Mann-Whitney U test was conducted to compare mean discrepancy among the groups showed no significant difference between group I and group II (p > 0.05) whereas comparison of groups I and II with group III showed a significant difference (p < 0.01). The proposed algorithm for the generation of defect template for manual plate bending during secondary reconstruction of mandibular defects is valid with acceptable accuracy in various defect configurations.

The Value of Three-Dimensional Modeling on Repositioning and Soft Tissue Filling in Microsurgical Reconstruction of Secondary Mandibular Defects: A Retrospective Study.

PurposeSecondary mandibular defect reconstruction is a challenging operation. It is performed rather rarely, as in most of the cases a primary reconstruction is preferable. Restoration of function and symmetry, in secondary reconstruction of mandibular defects, requires accurate repositioning of segments and appropriate soft tissue filling. The purpose of this study is to estimate the value of three-dimensional (3D) digital modeling to meet the above requirements, in secondary microsurgical reconstruction of mandibular defects.MethodsFive cases of mandibular defects, with various degrees of asymmetry and dysfunction, were restored secondarily, with fibula flaps, after virtual reconstruction on a 3D model derived from their computed tomography, with the utilization of CAD-CAM software. Software reproduced symmetrical 3D models by mirroring the healthy side. Occlusion was restored by fine adjustments on 3D models and finally a reconstruction plate was pre-bent on them, prior to its sterilization for use in surgery. Three out of the five cases received an osteo-cutaneous flap, while in the other two patients, an osseous flap was used. Lower face symmetry, mouth opening, and main patient’s complaints were evaluated pre- and postoperatively to assess the value of the 3D modeling.ResultsAll flaps survived. Hematoma occurred in two patients and was resolved after evacuation. In two patients, a fistula observed, was attributed to screw loosening, and treated after a surgical debridement and screw replacement. Intraoral exposure in the posterior part of the fibula flap was recorded in one patient, possibly from wound dehiscence due to tension of the intraoral tissue, and successfully covered with an ipsilateral nasolabial flap. The resulting symmetry and function were satisfactory in all the patients.ConclusionSecondary mandibular defects are often related with cosmetic disfigurement, misalignment of mandibular segments, and mandibular malfunction. For the correction of mandibular continuity, symmetry, and restoration of function, preoperative 3D modeling may be an important tool, according to our results.

Safety and efficacy of secondary mandibular reconstruction using a free osteo-cutaneous fibula flap after segmental mandibular resection: a retrospective case\u2013control study

BackgroundFree osteocutaneous fibula flap (FFF) is currently considered the best option for segmental mandibular reconstruction; however, there are only a few reports comparing secondary with primary reconstructions using FFF. This study aimed to evaluate the safety and efficacy of secondary mandibular reconstruction using FFF when compared with primary mandibular reconstruction.MethodsFrom October 2018 to February 2020, patients who underwent mandibular reconstruction using FFF after segmental mandibulectomy were retrospectively reviewed. The size and location of the mandibular defect, the segment length and number of osteotomies in the fibula, types of the mandibular plating system, kinds and laterality of the recipient vessels were recorded from the surgical notes. Flap survival, duration of nasogastric tube use, and implant installation after reconstruction were recorded as postoperative evaluation indices.ResultsTwelve patients underwent mandibular reconstruction using FFF during the study period. There were no significant differences in demographic characteristics other than body mass index between the primary (n = 8) and secondary (n = 4) reconstruction groups. No significant differences were observed in the size and location of defects, the segment length and number of osteotomies in the fibula, and the types of mandibular plating system. There was no significant difference in the kinds of recipient vessels; however, the laterality of recipient vessels was ipsilateral in all cases of primary reconstructions and contralateral in all cases of secondary reconstructions. Three out of eight patients with primary FFF reconstruction developed partial flap necrosis. Four patients in the secondary FFF reconstruction group achieved complete flap survival. The duration of use of the nasogastric tube and implant installation after reconstruction was comparable between the two groups.ConclusionSafe and effective secondary mandibular reconstruction can be performed in this clinical case study using FFF.

External fixation greatly improves outcomes in the surgical treatment of osteoradionecrosis of the jaws without affecting quality of life: a five-year retrospective study.

Osteoradionecrosis of the jaw can be treated using both conservative treatment and surgery. External fixation may be used to bridge large resection defects after sequestrectomy for stabilisation and before secondary mandibular reconstruction. We designed a retrospective analysis of 70 patients with osteoradionecrosis treated between the years 2014 and 2018, and found that the use of external fixation greatly improves their outcomes. Patients were grouped according to Notani's classification: those who had Notani I disease were treated surgically but without external fixation; and those with Notani II and Notani III disease were eligible for external fixation. In those with Notani II disease, there was a significant reduction in the number of pathological fractures that occurred with external fixation. In those with Notani III disease, the success rate of primary sequestrectomy was only 1:14; however, those treated with external fixation all successfully healed after their first operation. It was hypothesised that although external fixation would improve outcome, it would come at a detriment to their quality of life (QoL). However, in a subset of these patients, we showed that in addition to increasing successful healing, patients' QoL with the external fixator was no worse than when they had an active osteonecrotic lesion. The treatment of osteoradionecrosis is cumbersome and advanced stages are associated with more complications. The use of an external fixator significantly reduces the probability of pathological fractures and increases the rate of successful healing in patients after mandibular resection. It does this without greatly interfering with patients' lives, while improving their condition sufficiently to allow for subsequent mandibular reconstruction.

A new procedure assisted by digital techniques for secondary mandibular reconstruction with free fibula flap

Background and Objectives: To describe a new procedure assisted by digital techniques for secondary mandibular reconstruction with free fibula flap. Methods: The three-dimensional (3D) reconstruction images for vessels was used to demonstrate the vascular diameter and location, which help select the most suitable vein and artery for anastomosis. Maxillary and mandibular stone models of the patient were fabricated and a stable occlusal relationship was determined on an articulator. 3D tooth model data were scanned using a 3D optical measuring system, and the obtained stereolithographic (STL) data was imported to Geomagic software. Preoperative maxillofacial and fibular noncontrast-enhanced computed tomography scans were acquired, and the data were imported to ProPlan CMF software. The maxilla and mandible were segmented, and STL data were imported to Geomagic software. The registration function was used to determine the ideal mandibular position. First, with the maxillary position fixed, the maxillary and mandibular models were registered with the maxilla. Then, with the tooth model positions fixed, the mandible was registered with the models. Virtual plan and surgical navigation was used to design and correct the mandibular and fibular position. Findings and Conclusion: Our technique enabled precise recovery of the original mandibular configuration in this patient.

Secondary mandibular reconstruction for paediatric patients with long-term mandibular continuity defects: a retrospective study of six cases

Paediatric patients with long-term mandibular continuity defects following segmental resection usually present severe functional and cosmetic deformities. Secondary mandibular reconstruction for these patients is very challenging. Literature reports on how to handle these patients are scarce. The aim of this study was to describe the authors’ experience in handling those paediatric patients who have not undergone primary reconstruction, for whom the final goal of treatment is to restore a symmetrical facial appearance, masticatory function, and speech. This was a retrospective analysis of the data of six patients who underwent radical mandible resection in childhood, without immediate bone restoration, and who then underwent a secondary mandibular reconstruction procedure after reaching adulthood, during the period 2009 to 2015. The multidisciplinary treatment procedure, selection of the donor site, and reconstructive approach are discussed. Key points in relation to secondary mandibular reconstruction with the aim of achieving not only good functional and cosmetic results, but also an improvement in the paediatric patient's psychological and social outcomes, are emphasized.

A New Procedure Assisted by Digital Techniques for Secondary Mandibular Reconstruction With Free Fibula Flap

To describe a new procedure assisted by digital techniques for secondary mandibular reconstruction with free fibula flap. The 3-dimensional (3D) reconstruction images for vessels were used to demonstrate the vascular diameter and location, which help select the most suitable vein and artery for anastomosis. Maxillary and mandibular stone models of the patient were fabricated and a stable occlusal relationship was determined on an articulator. The 3D tooth model data were scanned using a 3D-optical measuring system, and the obtained stereolithographic (STL) data were imported to Geomagic software. Preoperative maxillofacial and fibular noncontrast-enhanced computed tomography scans were acquired, and the data were imported to ProPlan CMF software. The maxilla and mandible were segmented, and STL data were imported to Geomagic software. The registration function was used to determine the ideal mandibular position. First, with the maxillary position fixed, the maxillary and mandibular models were registered with the maxilla. Then, with the tooth model positions fixed, the mandible was registered with the models. The STL data for the mandible were imported to ProPlan CMF software. Virtual plan and surgical navigation were used to design and correct the mandibular and fibular position. Our technique enabled precise recovery of the original mandibular configuration in this patient. The shift in the reconstructed mandible and fibular segment was <5 mm. The authors described a new procedure for secondary mandibular reconstruction with a free fibular flap using digital techniques involving surgical navigation, which have the potential to improve the clinical outcomes of this procedure.

CAD/CAM guided secondary mandibular reconstruction of a discontinuity defect after ablative cancer surgery

A surgical guide is projected to aid the repositioning of the mandibular segments in their original locations, and a reconstruction bone plate is provided to support the fibula free flap. Computer-aided mandibular reconstruction involves three steps: virtual surgical planning, CAD/CAM and rapid-prototyping procedures for the design and manufacture of the customised surgical device and surgery. The duration of the reconstructive phase (<1.5 h intraoperative time) was reduced in comparison with traditional secondary mandibular reconstruction. The bone plate permitted the maximal restoration of the original facial and mandibular contours and the more precise positioning of the residual mandibular ramus in comparison with conventional procedures. No complication was noted during the mean follow-up period of 12 months. The protocol presented in this paper offers some benefits: 1) The virtual environment permitted ideal preoperative planning of mandibular segment repositioning in secondary reconstruction; 2) Intraoperative time was not consumed by approximate and repeated bone plate modelling; 3) Using CT data obtained before primary surgery, the reconstruction bone plate was designed using the original external cortical bone as a template to reproduce the ideal mandibular contour; 4) Prototyped resin models of the bone defect allowed the surgeon to train preoperatively by simulating the surgery.

Indications and Outcomes for Mandibular Reconstruction Using Sequential Bilateral Fibula Flaps

A subset of patients with recurrent or second intraoral tumors undergo both primary and secondary mandibular reconstruction using bilateral fibula flaps. The objective of this report is to describe indications and outcomes for these patients. A retrospective analysis of a prospectively collected database was performed. Charts were reviewed to identify demographics, operative features, and functional outcomes. Ten patients underwent mandibular reconstruction with a second fibula flap for recurrent or second oral tumors. Time between flaps averaged 20 months. Bone gap size measured 8 cm after both resections. Eighty percent of secondary resections included the mandibular arch, in contrast to 20 percent of primary resections (p=0.070). Compared with primary resections, secondary soft-tissue defects were larger and more frequently included composite tissues. There were low complication rates and no flap failures after both reconstructions. Functional evaluation showed a greater dependency on supplemental enteral nutrition after the second resection (p=0.033). Five patients died at a median of 12.5 months after the second resection and the remaining patients have survived for a median of 18.6 months. The principal indication for second fibula flaps in mandibular reconstruction is central segment defects where rigid support is required to prevent sequelae of the Andy Gump deformity. For lateral resections, the large soft-tissue deficits of secondary extirpation may be better served by reconstruction with soft-tissue flaps. Second osseous free flaps can be performed safely, but with a significant decline in postoperative oropharyngeal function. Goals of surgery and quality of life need to be addressed before ablation of recurrent or second oral tumors is performed.

A pedicled mandibular osteomuscular flap for reconstructing composite mandibular defects

AbstractAim: The aim of the present study was to evaluate the reliability of reconstructing composite defects of the mandible with a local pedicled mandibular osteomuscular flap.Materials and methods: A retrospective study examined patients undergoing secondary mandibular reconstruction following tumour ablation using local pedicled mandibular osteomuscular flaps. The study included five men and three women. The segmental defects of the mandible resulted from oral carcinoma in five cases and mandibular ameloblastoma in three.Results: All of the flaps survived. Proper aesthetics and complete functionality were obtained, and no donor‐site problems occurred. The patients were followed for 16–24 months and no recurrence was seen.Conclusions: The pedicled mandibular osteomuscular flap is technically simple, fast to harvest, and has an exceptionally long arc of rotation, which enables the reconstruction of composite segmental defects of the mandible following tumour ablation.

Secondary Mandibular Reconstruction After Oral Squamous Cell Carcinoma Resection

Besides bone grafting, transport disk distraction osteogenesis (TDDO) is an alternative approach that can be used for the reconstruction of the mandibular arch after neoplastic surgery. Although several animal experiments are reporting about the applicability of this technique, little is known about its long-term success in human beings. In this study, we report about the successful treatment of patients with defects of their mandibular arch due to tumor resection by means of the external bifocal TDDO. A total of 7 patients (n = 3 with lateral, n = 4 with anterior defects) were followed up for a mean period of 56 months. Although neither adjuvant nor neoadjuvant chemotherapy negatively influenced callus formation, prereconstructive radiation with a dose of 51 Gy led to an insufficient callus formation. The reconstruction of anterior defects was unsatisfying because tensions from the soft tissue on the fragile and rubber-like callus negatively influenced the natural arch shaping.In these cases, additional surgery was often required. However, reconstruction of lateral defects of the mandibular arch was more successful and resulted in functional bone with good quality, in which dental implants could be inserted. The results of this study emphasize that TDDO by means of bifocal distraction provides functional bone comparable to residual bone.Lateral defects of mandibular arch can be better reconstructed, whereas anterior defects often require additional surgery.

Prefabricated bony radial forearm flap for secondary mandible reconstruction after radiochemotherapy

Primary reconstruction of the mandible is the golden standard of surgical treatment after ablative tumor surgery. Many different microvascular bone grafts are used to reduce wound healing complications at the severely compromised recipient site. The loss of primary grafts due to radiotherapy or osteoradionecrosis can make secondary mandibular reconstruction necessary. To address this problem, we developed the technique of the prefabrication of a radial forearm flap with cancellous bone. The aims were to establish these techniques into the clinical routine and to create a safe and reliable flap with low donor site morbidity. In patients who had undergone ablative tumor surgery radiochemotherapy, and primary reconstruction, prefabricated bony radial forearm flaps (PBRFFs) were applied for secondary reconstruction of the mandible. Cylinders of cancellous bone taken from the iliac crest were implanted in the lower forearm to allow the necessary vascularization. After a healing period of 4 weeks, the PBRFF was elevated and grafted into the mandibular defect. All grafts healed uneventfully. However, 1 case required revision of the venous anastomosis after 2 days. The transplants improved the contour of the lower face enabling a good correction of the facial asymmetry. During the follow-up of up to 4 years, the radiographic controls showed good bony consolidation between the graft and the stumps of the mandible as well as formation of cortical bone around the cancellous bone cylinders. These results demonstrate that the PBRFF is a safe and reliable graft which provides alternate solution in which other microvascular bone grafts have already failed. In the future, the iliac bone graft may be replaced with scaffold seeded with stem cells for further reduction of donor site morbidity.

Comparison of reconstructive procedures in primary versus secondary mandibular reconstruction

Comparison of reconstructive procedures in primary versus secondary mandibular reconstruction

Osteosynthesis and simultaneous irregular trifocal distraction osteogenesis for segmental mandibular defect after tumor ablative surgery: a case report

This paper describes a case of secondary mandibular bone reconstruction performed to place dental implants. Osteosynthesis and simultaneous irregular trifocal distraction osteogenesis were documented. The patient was a 51-year-old man with recurrent ameloblastoma of the mandible. Segmental mandibulectomy for tumor ablation and immediate mandibular reconstruction were performed. Because the volume of reconstructed bone was insufficient to place dental implants, trifocal distraction osteogenesis (vertical and horizontal distraction osteogenesis) was performed. Because the mandible had lost its continuity, osteosynthesis was performed simultaneously. Through this procedure, the bone was well augmented. Absorption of the distracted bone was not seen. Adequate-length implants were placed. Irregular trifocal distraction osteogenesis synchronized with osteosynthesis shortened the treatment period and produced stable bone augmentation for placement of dental implants. Therefore, this procedure could be indicated for complicated segmental mandibular bone defects.

Distraction osteogenesis in secondary microsurgical mandible reconstruction: Report of seven cases

Fibula, ilium and scapula are the preferred donor areas for vascularised bone grafts. For secondary mandibular reconstruction, however, compromises often have to be made as a result of the poor quality of the covering soft tissue and recipient vessels especially in irradiated patients. Callus distraction osteogenesis is a complementary method for optimising the intermaxillary relationship and the facial profile from an aesthetic point of view. Thirteen distractions were performed in seven patients following microsurgical mandibular reconstruction over a period of 4 years, all by the same surgeon. Intra-oral distraction devices were predominantly applied. After a 7-day healing period, the callus distraction was begun, involving two advisements per day of 0.5mm each. The distraction devices were removed after a consolidation phase of 4-5 months. Ten of the 13 distractions were uneventful with an average bone lengthening of 20mm, retained after a follow-up time of 6-47 months (average 27 months). The intermaxillary relationship and the facial profile were improved in all cases. Distraction plate fractures, screw loosening or absence of new bone formation were the complications encountered in the other three patients. Regarding the high complication rate, a successful outcome cannot be expected with greater certainty. Thus the indication should be stringent when including this procedure within the possible treatment alternatives available to the clinician.

Treatment rationale for pathological fractures of the mandible: a series of 44 fractures

This paper reports on the largest series of pathological fractures of the mandible ( n = 44) in the literature, with the aim of proposing an aetiologic classification and algorithm for treatment. A retrospective review was undertaken of cases treated in the Department of Oral and Maxillofacial Surgery at the University of Maryland Medical Center from 1991 to 2005. Data collected included age, gender, race, aetiology, site, management and outcome. Forty-three patients with 44 pathologic fractures were included. The most common aetiology was osteoradionecrosis (49%), followed by infections (19%) and malignancy (19%). The most frequent primary treatment utilized was mandibular resection of diseased bone and fixation with a locking reconstruction plate alone (55%). Either primary or secondary mandibular reconstruction was performed when co-morbid disease allowed such treatment. Management of pathological fractures is aimed initially at systemic issues, followed by focusing on site-specific issues. This is a complex problem with a 40% complication rate, with radiation therapy associated with 59% of the complications. Free flap reconstruction should be considered when possible, especially in cases secondary to osteoradionecrosis.