Stereolithographic model-assisted reconstruction of the mandibular condyle with a vascularized fibular flap following hemimandibulectomy: Evaluation of morphological and functional outcomes

Osteo-cutaneous microvascular free-flaps are a viable option for reconstructing the temporomandibular joint

Background

There are multiple reconstructive options after mandibular resection and disarticulation of the condyle. The purpose of this study was to assess the clinical outcomes and functionality of osteocutaneous free flaps in the reconstruction of mandibular defects that involve the Temporo-Mandibular Joint (TMJ).

Methods

Our study is a retrospective cohort study involving subjects who underwent mandibular resection and needed TMJ reconstruction with vascularized bony-free flaps from February 2016 to June 2018. Data gathered included patient demographics, post-operative function, maximum interincisal opening (MIO), occlusion status, deviation on opening, and TMJ symptoms. Data points collected from postoperative CT imaging included the following: position of the flap in relation to the glenoid fossa and articular eminence, and closest point of contact.

Results

Eight out of the nine patients who underwent free flap reconstruction of mandibular defects involving the TMJ qualified for the study. The mean age was 39.7 years old. In all 8 cases, virtual surgical planning (VSP) was used. The mean follow-up time was 18.75 months. The flap success rate was 100%. The mean MIO was 37.37 mm. Six patients resumed their premorbid diet, and one patient developed dysphagia and was peg tube dependent. In seven cases the occlusion was intact and reproducible, one case was without sufficient teeth for occlusion. On imaging, the mean distance from the neo-condyle to the glenoid fossa was 14 mm and to the articular eminence 8.68 mm. The point of closest contact in all cases appeared to be the articular eminence.

Conclusion

Vascularized Osteocutaneous-flaps such as FFFs and DCIA flaps provide a good option for the reconstruction of mandibular defects that involve the TMJ. Ipsilateral deviation on opening does not negatively affect clinical outcomes or function. Placing patients in Maxillomandibular fixation for 4-6 weeks may help to prevent condylar sag and provide stable post-operative occlusion.

Poor condyle position after mandibular reconstruction and a classification system for patients with "VSCU" based on computed tomography: a cross-sectional study with retrospective data collection

Background

Although the application of vascularized free bone muscle flap to reconstruct the mandible has become a standardized approach for mandible reconstruction, the results of its reconstruction are not always satisfactory. The purpose of this study was to identify the types of mandibular and condylar defects by analyzing the unsatisfactory cases of mandibular reconstruction in clinical practice, and to provide some clinical experience of reconstruction.

Methods

Our study retrospectively analyzed 364 patients who underwent mandibular resection and vascularized free bone flap reconstruction of the mandible and temporomandibular joint (TMJ). We innovatively proposed a "VSCU" classification system (V: vertical position, S: sagittal position, C: coronal position, U: condylar resection is not required) by analyzing computed tomography (CT) scans of mandibular branches and TMJs.

Results

In all, 221 cases of free iliac muscle flap and 143 cases of fibula muscle flap were included in this study, of which 23 cases had unsatisfactory results after TMJ reconstruction. We classified 23 patients with unsatisfactory mandibular reconstruction according to the "VSCU" classification system. The most common type was U + V + SfC (n=8), followed by V - SfC + U + (n=4), V - s + C + U + (n=3), V - sbcou - (n=3), V - SBC + U + (n=2), V - s + C + U - (n=1). The most common classification was insufficient mandibular rami length, followed by condylar sagittal anteriorization. There was no significant change in the position of condyle on the healthy side during mandibular reconstruction involving condyle. P1 on the affected side was 52.28±4.17 mm before operation and 58.94±5.65 mm after operation, P<0.01; P2 was 12.83±3.49 mm before operation and 24.90±7.15 mm after operation. S2 was 4.54±2.84 mm before operation and 19.10±8.54 mm after operation. A2 was 11.46±3.35 mm before operation and 24.15±8.29 mm after operation. The P values were all less than 0.01, and the differences were statistically significant.

Conclusions

We propose to use the "VSCU" classification system for accurate 3-dimensional (3D) analysis and positioning, and then obtain accurate models through computer-aided design and manufacturing (CAD/CAM), which can reduce the occurrence of poor reconstruction effect and unreasonable joint position, and is worthy of clinical promotion.

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.

[Implant-prosthetic rehabilitation of a patient with an extensive maxillofacial defect]

The paper presents a clinical case demonstrating the necessity for scarce dental implants surgery in tissues affected by multiply surgical and radiological procedures. The patient underwent 13 interventions, 4 reconstructive procedures and 3 courses of radiotherapy resulting in extensive facial defect. An orthopedic construction was fixed in a defect on mechanically stable single-stage implants with screw-retained orthopedic platform and trans-zygomatic implants on the contralateral side. The method is based on virtual diagnostics and choice of materials for 3D-prototyping of a framework to fill the defect and serve as supportive element for fixation and stabilization of obturator and facial mask.

Association between condylar position changes and functional outcomes after condylar reconstruction by free fibular flap

OBJECTIVES

Stable and appropriate condyle positioning is necessary for maintaining temporomandibular joint function. It is unclear if this position remains stable in patients after free fibular flap (FFF) condylar reconstruction. We investigated whether condylar position deviated after reconstruction, and whether this affected functional recovery.

MATERIALS AND METHODS

We retrospectively reviewed 43 patients who underwent conventional FFF condylar reconstruction, and 5 patients who underwent reconstruction by computer-assisted three-dimensional (3D) printing methods. Three-dimensional models were built from cone-beam computed tomography images obtained immediately postoperatively and 1-year postoperatively. The glenoid fossa and fibular condyle centers were used to measure the fibular condyle position in the models. Clinical examination indices, including maximum mouth opening (MMO), pain during chewing/mouth opening, and patient satisfaction with mastication and 1-year outcomes were assessed.

RESULTS

Fibular condyle position changed significantly over 1 year in both groups (P < 0.05). Clinical examination at 1 year after the surgery showed that in the conventional group, the MMO range was ≥ 35 mm in 76.7% of patients and < 35 mm in 23.3% of patients; 4.7% experienced pain during chewing/mouth opening, and 7% were dissatisfied with treatment outcomes. In the 3D printing group, all patients had an MMO range exceeding 35 mm, none had pain, and all were satisfied with functional outcomes.

CONCLUSIONS

The position of the fibular condyle deviates after reconstructive surgery, but it is unlikely to affect functional recovery.

CLINICAL RELEVANCE

These findings can form the basis for evaluation of functional outcomes of patients who have previously undergone condylar reconstruction by FFF.

Guidelines for the Surgical Management of Oral Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to provide guidance on the implementation of a surgical treatment of oral cancer. MEDLINE databases were searched for articles on subjects related to “surgical management of oral cancer” published in English. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. The quality of evidence was rated with use RoBANS (Risk of Bias Assessment Tool for Nonrandomized Studies) and AMSTAR (A Measurement Tool to Assess the Methodological Quality of Systematic Reviews). Evidence-based recommendations for practice were ranked according to the American College of Physicians grading system. Additional directives are provided as expert opinions and Delphi questionnaire when insufficient evidence existed. The Committee developed 68 evidence-based recommendations in 34 categories intended to assist clinicians and patients and counselors, and health policy-makers. Proper surgical treatment selection for oral cancer, which is directed by patient- and subsite-specific factors, remains the greatest predictor of successful treatment outcomes. These guidelines are intended for use in conjunction with the individual patient’s treatment goals.

[Evolution of the mandibular defects reconstruction with free fibula flapx]

One of the most important steps in achieving aesthetical and functional result in mandible reconstruction with fibula free flap is positioning of the bony part relative to the basis of the native mandible. Positioning fibular bony part continuing inferior mandible border may produce a high discrepancy between the residual mandible and fibula bone that results in difficulty in denture rehabilitation. Positioning fibular bony part continuing alveolar mandible border creates asymmetric jowls and changed shape of jawline in border-line zone. The double-barrel technique solves this problem, but needs a meticulous preoperative planning and precision free fibula flap modelling.