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

Biomechanical Evaluation of Hydroxyapatite/poly-l-lactide Fixation in Mandibular Body Reconstruction with Fibula Free Flap: A Finite Element Analysis Incorporating Material Properties and Masticatory Function Evaluation

In reconstructive surgery following partial mandibulectomy, the biomechanical integrity of the fibula free flap applied to the remaining mandibular region directly influences the prognosis of the surgery. The purpose of this study is to evaluate the biomechanical integrity of two fixation materials [titanium (Ti) and hydroxyapatite/poly-L-lactide (HA-PLLA)]. In this study, we simulated the mechanical properties of miniplate and screw fixations in two different systems by finite element analysis. A three-dimensional mandibular model was constructed and a fibula free flap and reconstruction surface were designed. The anterior and posterior end of the free flap was positioned with two miniplates and two additional miniplates were applied to the angled area of the fibula. The masticatory loading was applied considering seven principal muscles. The peak von Mises stress (PVMS) distribution, size of fixation deformation, principal stresses on bones, and gap opening size were measured to evaluate the material properties of the fixation. In the evaluation of properties, superior results were observed with both fixation methods immediately after surgery. However, after the formation of callus between bone segments at 2 months, the performance of Ti fixation decreased over time and the differences between the two fixations became minimal by 6 months after surgery. The result of the study implies the positive clinical potential of the HA-PLLA fixation system applied in fibula free flap reconstruction.

Segmental mandibulectomy and microvascular reconstruction with fibula free flap: Comparison between intraoral and extraoral approaches

BACKGROUND

Segmental mandibulectomy and reconstruction of resulting defect can be performed via intraoral approach (IOA) or extraoral approach (EOA). Both approaches have advantages, disadvantages, indications, and contraindications to consider during their selection.

OBJECTIVE

To compare IOA vs EOA of segmental mandibulectomy and microvascular reconstruction with fibula free flap (FFF).

METHODS

We conducted a retrospective cohort study in which 51 patients who underwent segmental mandibulectomy and microvascular reconstruction with FFF from 2020 to 2024 were included, especially 17 patients by IOA and 34 patients by EOA, representing both groups of this study. Clinical characteristics, surgery parameters, and patients' prognosis were evaluated. Patients' satisfaction and Derriford Appearance Scale (DAS59) were assessed during follow-up.

RESULTS

Ameloblastoma was the most frequent diagnosis (52.9% managed by IOA vs 70.6% by EOA); FFF was frequently positioned as double barrel (94.1% managed by IOA vs 88.2% by EOA). Compared with EOA group, IOA group had less intraoperative blood loss (mean difference [MD] = -112.2, 95% confidence interval [CI]: -178.9 to -45.5, p = 0.001), higher satisfaction score (MD = 1.3, 95% CI: 0.9 to 1.7, p ˂ 0.001), and lower DAS59 score (MD = -0.5, 95% CI: -0.7 to -0.2, p ˂ 0.001).

CONCLUSION

Both IOA and EOA were found safe and feasible, presenting similar perioperative features and postoperative outcomes. Patients managed with IOA were more satisfied with aesthetic outcomes than patients managed with EOA. In the absence of simultaneous immediate implant during mandibular FFF reconstruction, after stability of FFF on the defect site, patients should always be referred to an implantologist and/or prosthodontist for teeth restoration to improve functional and aesthetic outcomes.

Autogenous, alloplastic, or hybrid for total mandibular reconstruction; is here an optimal path?

For less fit patients, total reconstruction of the mandible (TRM) is an elucidated alternative for severe maxillofacial defects. This study aimed to comprehensively review and analyze the existing evidence, irrespective of the underlying pathologies, to provide a consolidated overview of the current state of TRM. An electronic search was performed on PubMed, Embase, Scopus, and Google Scholar to identify studies reporting TRM without restrictions on patient age, type of pathology underlying the mandibular defect, and study type. Electronic search identified 390 studies; only 21 met the inclusion criteria, documenting 7 (33.3%) autogenous, 6 (28.6%) alloplastic, and 8 (38.1%) hybrid TRMs. All studies reported one clinical case, except for two studies that reported two patients treated with TRM. The mean age of the patients was 39.0 ± 19.4 years, and the mean follow-up was 22.3 ± 14.7 months. Osteomyelitis was the most common pathology. Bilateral condyles were preserved in only two cases. The TRM has been reported in clinical cases only and no large cohort study is available. Functional and aesthetic parameters have either not been reported or have been reported in heterogeneous formats, thus hampering comparisons of autogenous, alloplastic, and hybrid TRMs. Overall, TRM in patients presenting with severe maxillofacial defects achieved promising clinical outcomes endowed with acceptable function and aesthetics. Large cohort studies are needed to validate these results.

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

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

Secondary Reconstruction of Head and Neck Cancer Defects-Principles in its Practice

Objective

Secondary reconstruction is requested by patients who have completed their head and neck cancer treatment. The reason for the request for reconstruction may be to improve the functional deficits, achieve aesthetic refinements or most commonly both. The article looks at various issues related to reconstruction in the secondary setting and suggesting the ways to approaching patients requesting secondary reconstruction.

Discussion

While considering secondary reconstruction, various factors need to be considered. These include issues related to the disease, the treatment received as well as the patient's comorbid conditions. Aggressive disease and multiple recurrences should deter from undertaking complex reconstructions. Lack of tissue pliability resulting in a woody neck due to radiation makes dissection difficult and wound healing poor. The reconstructive requirements include release of contractures inside the mouth, reconstruction of the missing jaws, replacement of the missing volume of the tongue and correction of the incompetent angle of mouth. Goals of reconstruction should be prioritized by the surgical team. Free soft tissue or bone containing flaps would be provided ideal tissue to meet the reconstructive requirements in secondary reconstruction. However, several impediments could exist for their safe use. Release of contractures and provision of adequate soft tissue should be given priority and must be addressed before bony reconstruction is contemplated.

Conclusion

Bony reconstruction of both mandible and maxilla is possible, with the former being more difficult to deliver good results due to the associated soft tissue fibrosis. Virtual surgical planning with the aid of Stereo lithographic models and planning software will improve the quality of bony reconstruction. Detailed counseling sessions involving patient and the family are essential before embarking on secondary reconstruction as the patient expectations and the surgical outcome may not be easy to match. However excellent improvement in function and appearance will be possible in many patients with appropriate reconstructive procedure.

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

Purpose

Secondary 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.

Methods

Five 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.

Results

All 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.

Conclusion

Secondary 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.

Minimally Invasive Two-Staged Surgery in the Treatment of Large Cystic Lesions of the Jaw

Background: Cystic lesions of the jaw are commonly found in clinical practice. Large, expansive cysts raise challenges for the clinician from both diagnostic and surgical perspectives. The aim of our work is to present a combined, two-staged surgical approach in histologically confirmed non-aggressive cystic lesions of the jaw. Methods and Results: We report the case of an extensive mandibular cyst, associating a high risk of bone fracture, that is treated in the initial stage by cystic decompression through marsupialization with concomitant histological diagnostic confirmation, followed in the second stage by radical excision and mandibular reconstruction with titanium mesh, with the purpose of prevention for oro-cystic chronic fistula formation. Conclusions: Large odontogenic mandibular cysts imply a meticulously conducted assessment and treatment. Marsupialization should be taken into consideration for the treatment of large cystic lesions, followed by secondary enucleation, with minimal risks for the patient. The soft tissue healing process can be optimized with the use of titanium meshes, as an alternative for other reconstructive techniques, in the management of large cystic lesions.