Extended total temporomandibular joint replacements: a classification system

3D-printed temporomandibular joint-mandible combined prosthesis: A prospective study

OBJECTIVES

The study aimed to introduce and evaluate a new customized temporomandibular joint-mandible combined prosthesis with 3D printing fabrication.

MATERIALS AND METHODS

This was a prospective study including patients with temporomandibular joint-mandible combined lesions. A 3D-printed customized temporomandibular joint-mandible combined prosthesis was implanted to repair the joint and jaw defect. Clinical follow-up and radiographic examinations were taken to assess the clinical efficacy. The assessment indices were compared by the Wilcoxon signed rank test.

RESULTS

Eight patients were treated with the combined prosthesis and included in this study. All prostheses were accurately positioned and fixed without wound infection, prosthesis exposure, displacement, loosening, or fracture. All cases had no mass recurrence at the last follow-up point. Pain, diet, mandibular function, lateral mandibular movement to the diseased side, and maximal interincisal opening showed significant improvements at every follow-up point and went to a stable condition at 6 months after the operation. But the lateral movement to the non-operated side was still limited following surgery.

CONCLUSION

The 3D-printed combined prosthesis may be an alternative to other well-established reconstructions for temporomandibular joint and mandible defects.

Trans-mastoid anchorage as a novelty in glenoid fossa reconstruction for hemifacial microsomia with agenesis of zygomatic arch and external acoustic meatus-Technical note with a case illustration

Total joint reconstruction (TJR) has become the most preferred method of reconstruction in recent years for hemifacial microsomia (HFM). This requires meticulous planning for the glenoid fossa and ramus prosthesis along with the arch in certain indications. TJR in a type V HFM is extremely challenging due to agenesis/hypolasia of the zygoma and arch which compromises anchorage of the glenoid prosthesis. Conventional options used for such indications incorporate extended designs for the fossa. However, the two designs used commonly are associated with limitations; (i) the temporal extension is overtly large and cannot be anchored in patients with thin temporal bone and (ii) the glenoid fossa incorporated into the arch prosthesis, where the fossa is not positioned on stable bone and occlusal loading is non-physiological; transmitted onto the arch prosthesis rather than the skull base. The authors propose the use of the mastoid process as an alternative for anchorage of fossa prosthesis. This technique offers stable anchorage while facilitating ideal positioning on the skull base for optimal masticatory load transmission. The case illustration depicts reconstruction of the TMJ, zygoma and the zygomatic arch in a 31-year-old man with type V HFM, with a three-year follow-up, with good clinical outcomes sans complications.

Extended Total Temporomandibular Joint Replacement - A Feasible Option for Functional and Aesthetic Reconstruction of Mandibular Defects Involving the Temporomandibular Joint

Study design: Retrospective case series. Objective: Alloplastic temporomandibular joint replacement has been established as a standard technique for end- stage temporomandibular (TMJ) pathologies. Joint replacement when there are extensive mandibular defects remains a challenging clinical problem. Custom-made extended temporomandibular joint replacement is a feasible option but there is limited information about this emerging technique. Methods: Included were all patients undergoing extended TMJ-replacements (TMJe), all operatrions were carried out by the senior author. Surgical technique was either single stage or two stage protocol. Surgical details and pitfalls and outcome of more than 2 years follow-up with reference to thirteen including twelve patients were recorded. Results: The most common diagnosis was ameloblastoma of the mandibular ramus. Single stage or two stagge regime were carried out depending on resection requirements and involvement of teeth. Improved mouth opening of more than 30mm was achieved in 10 of 12 patients. One patient with previous TMJ replacement reported temporary weakness of the facial nerve, which resolved after 10 months. Conclusions: The authors suggest a simplified anatomically based single-stage or two-stage regime, with both regimes achieved excellent anatomic reconstruction, facial appearance and function with low surgical morbidity. Custom-made extended temporomandibular joint protheses appear an advanced and reliable solution for reconstruction of combined complex mandibular defects including the temporomandibular joint. If surgical clearance of the pathology can be achieved, a single-stage regime is favoured.

Extended total temporomandibular joint reconstruction prosthesis: A comprehensive analysis

Alloplastic total temporomandibular joint replacement (TMJR) is the treatment of choice for end-stage temporomandibular joint diseases. Extended TMJR (eTMJR) is a modification of the standard alloplastic fossa-condyle joint that includes components extending further to the skull base or the mandible. The aim of this study is to review the use of the eTMJR prosthesis for the treatment of large craniomaxillofacial defects. Data mining was performed according to the PRISMA statement using online search in databases such as PubMed (Medline), Google Scholar, Dimensions, Semantic Scholar and Web of Science. A total of 19 case reports, 08 case series and 03 retrospective studies were identified. A total of 49 patients were presented in the case reports and case series, who were implanted with 56 eTMJR prostheses (07 bilateral and 42 unilateral procedures). The mean age of the patients was 36.02±16.54 years, the male to female patient ratio was 1:1.72 and the mean follow-up time was 23.74 ± 19.83 months. The eTMJR prosthesis was most frequently used to treat ameloblastoma and hemifacial microsomia. Analysis of the retrospective studies was performed in three domains: the baseline characteristic of patients, treatment outcomes in terms of functional variables and complications after eTMJR prostheses implantation. This study concluded that the implantion of the eTMJR prosthesis was uncommon, that appropriate class of eTMJR prosthesis was not reported, and that the width of the mandibular component (like the length) of eTMJR prosthesis has substantial variations.

Recent Advances in Temporomandibular Joint Surgery

Temporomandibular disorders (TMDs) affect a high percentage of children and adults worldwide. Surgery may be indicated in severe or recalcitrant cases. Several recent advancements in TMD and temporomandibular joint (TMJ) surgery have elevated understanding and the ability to treat affected patients. We discuss recent advances in TMD epidemiology, juvenile idiopathic arthritis (JIA) of the TMJ, and surgical techniques and technologies. Technical advancements have been identified in TMJ arthroscopy, the treatment of TMJ subluxation and dislocation, and extended prosthetic total TMJ reconstruction (eTMJR). Overall, this review provides valuable insights into significant recent advancements in TMJ disorders and their surgical management.

Extended Complex Temporomandibular Joint Reconstructions Exploiting Virtual Surgical Planning, Navigation Assistance, and Custom-Made Prosthesis: A Comprehensive Protocol and Workflow

BACKGROUND

Alloplastic temporomandibular joint (TMJ) replacement is a well-established procedure in maxillo-facial surgery. However, the surgical management of large excision in this area requires complex reconstruction beyond the standard TMJ prosthesis.

OBJECTIVE

This study aims to describe the design and the consequential application of a protocol which involves the use of computer-assisted surgery tools to best face complex TMJ reconstruction (TMJR). Preoperative accurate study of every single case and intraoperative check of the surgical act are nowadays essential to perform such delicate surgical procedures.

MATERIALS AND METHODS

The study is a retrospective and single institution case series. The various processes of the management and planning of extended TMJ reconstruction (eTMJR) are extensively described, from the preoperative clinical evaluation, imaging acquisition protocols and virtual surgical planning (VSP), focusing also on the intraoperative transfer of VSP using navigation and surgical guides.

RESULTS

We included nine patients with different pathologies which were candidates for eTMJR. Overall, the application of our protocol and workflow permitted the reduction of complications and pain, and the improvement of the maximum interincisal opening (MIO) of the patients, restoring patients' masticatory function and esthetics.

CONCLUSIONS

The eTMJR should be considered as a safe and reliable surgical management modality in selected patients with large temporomandibular joint and skull base (TMJ-SB) lesions. An accurate preoperative protocol and workflow is essential to perform such insidious and complex reconstruction. However, more extensive studies on this type of device have to be conducted in order to validate its real usefulness and indications.

Introduction of temporomandibular joint and skull base combined reconstruction by autogenous bone graft

OBJECTIVE

This study introduces the application of autogenous bone graft for the reconstruction of temporomandibular joint (TMJ) and skull base combined defects.

MATERIALS AND METHODS

Patients treated with autogenous bone grafts for reconstruction of the TMJ and skull base were reviewed. All patients underwent virtual surgical design to confirm the osteotomies of the combined lesion and the selections of autogenous bone graft, fabrication of surgical templates to transfer the plan to actual operation, and reconstruction of autogenous bone graft for the TMJ and/or skull base. Surgical outcomes were assessed by clinical examinations and radiological data.

RESULTS

Twenty-two patients were involved in this study. Ten patients underwent reconstruction of the skull base by a free iliac or temporal bone graft and preservation of the TMJ. Twelve patients underwent skull base reconstruction by the same methods and total reconstruction of the TMJ by half sternoclavicular joint flap or costochondral bone graft. No severe complications occurred after surgery. The occlusion relationship was stable and similar to that of the preoperative state. The pain and maximal interincisal opening were significantly improved by the 101.2-month follow-up.

CONCLUSION

Autogenous bone graft is a good alternative for repairing the TMJ and the skull base structure and function.

CLINICAL RELEVANCE

The study introduced the application of autogenous bone graft for the reconstruction of temporomandibular joint and skull base combined defect, which is a good way to repair the defect and restore the function.

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.

Patient specific implant with high condylar neck osteotomy for temporomandibular joint preservation in segmental mandibulectomy

STUDY DESIGN

Letter to the Editor.

OBJECTIVE

Disarticulation may be considered during segmental mandibulectomy where margins necessitate high condylar neck osteotomy. Although a number of techniques have been reported for reconstruction of the condyle, successful preservation of normal joint anatomy, where possible, should be considered as a superior alternative. This report demonstrates a safe and predictable approach to condylar head preservation with high condylar neck osteotomy.

METHODS

We present two cases of native TMJ preservation with a very short salvageable condylar component utilising 3D-printed patient specific cutting guides and implants.

RESULTS

The condyle preserving reconstructive technique described successfully preserves the capsule of the TMJ, and with careful execution can preserve the intra-articular components of the joint and their relationships to each other. Both patients have experienced excellent outcomes to date.

CONCLUSIONS

As opposed to disarticulation reconstructions, this technique is more likely to achieve long-term normal occlusion, maintain normal alignment of reconstructed segments, and preserve condylar translation as opposed to simple hinging, in addition to avoiding the potential pitfalls of alternative techniques.

Total Alloplastic Temporomandibular Joint Replacement

Purpose

End-stage temporomandibular joint (TMJ) disease are not uncommon and affects quality of life. Multiple surgical procedures have been mentioned in literature for management of TMJ disease which ranges from conservative management to aggressive resection of involved joint and replacement with alloplastic total joint prosthesis. The purpose of the present paper was to provide an overview of the role of alloplastic total joint prosthesis in TMJ replacement.

Methods and results

Alloplastic total joint prosthesis is nowadays considered as a standard of care in the adult patients who require TMJ replacement. The requirement of alloplastic total prosthesis has increased in present era with the improvement in design and material of implants, surgical skills and reported victorious outcome along with improved quality of life after its use. It provides restoration of form and functions, improvement in quality of life, reduction in pain and maintenance of ramal height. Additionally, in TMJ ankylosis it reduces chances of re-ankylosis and allows facial asymmetry correction. Currently, enough evidence is however not available for replacement in skeletally immature patient.

Conclusion

The authors conclude that the total joint replacement is a standard procedure for end-stage TMJ disease. Every maxillofacial surgeon should be well-acquainted with TMJ replacement.

Accuracy of Guided Surgery and Real-Time Navigation in Temporomandibular Joint Replacement Surgery

Background: Sophisticated guided surgery has not been implemented into total joint replacement-surgery (TJR) of the temporomandibular joint (TMJ) so far. Design and in-house manufacturing of a new advanced drilling guide with vector and length control for a typical TJR fossa component are described in this in vitro study, and its accuracy/utilization was evaluated and compared with those of intraoperative real-time navigation and already available standard drilling guides. Methods: Skull base segmentations of five CT-datasets from different patients were used to design drilling guides with vector and length control according to virtual surgical planning (VSP) for the TJR of the TMJ. Stereolithographic models of the skull bases were printed three times for each case. Three groups were formed to compare our newly designed advanced drilling guide with a standard drilling guide and drill-tracking by real-time navigation. The deviation of screw head position, screw length and vector in the lateral skull base have been evaluated (n = 72). Results: There was no difference in the screw head position between all three groups. The deviation of vector and length was significantly lower with the use of the advanced drilling guide compared with standard guide and navigation. However, no benefit in terms of accuracy on the lateral skull base by the use of real-time navigation could be observed. Conclusion: Since guided surgery is standard in implant dentistry and other CMF reconstructions, this new approach can be introduced into clinical practice soon, in order to increase accuracy and patient safety.

Comparison in clinical performance of surgical guides for mandibular surgery and temporomandibular joint implants fabricated by additive manufacturing techniques

Additive manufacturing (AM) offers great design freedom that enables objects with desired unique and complex geometry and topology to be readily and cost-effectively fabricated. The overall benefits of AM are well known, such as increased material and resource efficiency, enhanced design and production flexibility, the ability to create porous structures and on-demand manufacturing. When AM is applied to medical devices, these benefits are naturally assumed. However, hard clinical evidence collected from clinical trials and studies seems to be lacking and, as a result, systematic assessment is yet difficult. In the present work, we have reviewed 23 studies on the clinical use of AM patient-specific surgical guides (PSGs) for the mandible surgeries (n = 17) and temporomandibular joint (TMJ) patient-specific implants (PSIs) (n = 6) with respect to expected clinical outcomes. It is concluded that the data published on these AM medical devices are often lacking in comprehensive evaluation of clinical outcomes. A complete set of clinical data, including those on time management, costs, clinical outcomes, range of motion, accuracy of the placement with respect to the pre-operative planning, and extra complications, as well as manufacturing data are needed to demonstrate the real benefits gained from applying AM to these medical devices and to satisfy regulatory requirements.

Intraoperative real-time navigation and intraoperative three-dimensional imaging for patient-specific total temporomandibular joint replacement

Customized solutions for replacement of the temporomandibular joint (TMJ) along with surgical guides enable precise and fast transfer of the virtual plan to the patient. However, these guides lack information on screw vectors and length, and well-defined borders for bony resections towards the medial skull base. This retrospective study was performed to investigate the feasibility and benefit of real-time navigation and intraoperative three-dimensional imaging during total TMJ replacement (TJR), as well as patient clinical outcomes. Between 2016 and 2020, 26 customized prostheses were implanted in 21 patients either with or without real-time navigation and instrument tracking. The clinical, surgical, radiological, and navigational data were analysed. The accuracy of navigation registration with instrument tracking, precision of screw insertion, and implant and screw positions were analysed by fusion of the virtual plan and surgical outcome. Real-time navigation aided orientation during lateral skull base dissection and resection. However, the results of real-time navigation-aided drilling were inconclusive regarding vector and length control. At a mean 15.3±3.0 months of follow-up, average mouth opening had improved from 21.69±2.80mm to 36.40±1.25mm; the average pain score decreased from 6.18±0.74 to 1.06±0.52. Thus, intraoperative real-time navigation for TJR assists lateral skull base dissection and resection.

Custom Alloplastic Temporomandibular Joint Reconstruction: Expanding Reconstructive Horizons

Custom alloplastic temporomandibular joint (TMJ) reconstruction has been well established for the management of end-stage TMJ disease. However, its use in congenital TMJ deformities is limited. Here, the authors present initial outcomes of skeletally mature patients who underwent custom alloplastic TMJ reconstruction and simultaneous orthognathic surgery.A retrospective case series of patients who underwent custom alloplastic TMJ reconstruction concurrent with orthognathic surgery between 2014 and 2019 was completed. Functional, aesthetic and orthodontic outcomes as well as complications were recorded.Seven TMJs in 5 skeletally mature patients (4 female, 1 male, ages 16-30) (2 bilateral, 3 unilateral) were replaced. All but 1 patient had previous attempts at reconstructive surgery with poor results. All cases were prepared using virtual surgical planning and underwent concomitant maxillomandibular orthognathic surgery. All patients demonstrated improved post-operative occlusions. Four of 5 patients achieved >30 millimeters of post-operative MIO. Complications included ear canal perforation and facial nerve dysfunction.There were no infections or other implant-related complications. Mean follow up was 2 years and 15 days. Alloplastic TMJ reconstruction at the time of skeletal maturity for patients with congenital mandibular TMJ defects is an alternative to existing management options. Further long-term prospective outcomes studies are ongoing.

Validation of an extended total joint replacement (eTJR) classification system for the temporomandibular joint (TMJ)

The aim of this paper was to validate a previously described classification system for extended total joint replacements (eTJRs) of the temporomandibular joint (TMJ). We engaged an expert panel to review 60 TMJ eTJR devices and classify them using the system, examining their responses for inter-rater agreement and concordance with the correct response as determined by the authors. Conger's kappa was 0.34 for the fossa (F) component sub-classification and 0.67 for the mandibular (M) component. A posthoc analysis showed improvements in inter-rater agreement for a modified three-tiered F sub-classification system which is suggested in a revised version of the TMJ eTJR classification system.

Extended Total Temporomandibular Joint Replacement with Occlusal Adjustments: Pitfalls, Patient-reported Outcomes, Subclassification, and a New Paradigm

Context:

Alloplastic temporomandibular joint (TMJ) replacement is a treatment strategy for segmental mandibular defects with occlusal abnormalities.

Aims:

To describe our experience with extended total TMJ replacement (eTMJR) by reporting operative obstacles, complications, and patient-reported outcomes, as well as to suggest a subclassification system and paradigm shift.

Setting and Design:

University hospital and private clinic; case series with retrospective follow-up.

Methods and Materials:

Five patients (6 eTMJRs) were followed for more than 1 year after surgery. Patient-reported outcomes were assessed using FACE-Q™ “Satisfaction with Outcome” questionnaires (sum and corresponding transformed Rasch scores).

Statistical Analysis:

Descriptive analyses were performed.

Results:

Problems were related to contralateral mandibular osteotomy healing (if performed), keying the prosthetic condyle into the fossa component, intra- and postoperative prosthetic lag, and intraoperative proper establishment of the occlusion when unilateral replacement was performed. Patients reported high satisfaction with the outcome, with a mean Rasch score of 89.2/100.

Conclusions:

Unilateral eTMJR obstacles related to three-dimensional rotational repositioning of the remaining mandible. We suggest a paradigm shift, considering primary alloplastic replacement instead of microvascular osseous transplantation for reconstruction when radiotherapy is not required. This can avoid donor site morbidity and long reconstructive surgery. An autologous osseous transplant is still available in case of implant failure. A subclassification system is proposed for eTMJR, which accounts for contour corrections, occlusal adjustments, and simultaneous contralateral mandibular osteotomy.

A review on computer-aided design and manufacturing of patient-specific maxillofacial implants

Introduction: Various prefabricated maxillofacial implants are used in the clinical routine for the surgical treatment of patients. In addition to these prefabricated implants, customized CAD/CAM implants become increasingly important for a more precise replacement of damaged anatomical structures. This paper reviews the design and manufacturing of patient-specific implants for the maxillofacial area.Areas covered: The contribution of this publication is to give a state-of-the-art overview in the usage of customized facial implants. Moreover, it provides future perspectives, including 3D printing technologies, for the manufacturing of patient-individual facial implants that are based on patient's data acquisitions, like Computed Tomography (CT) or Magnetic Resonance Imaging (MRI).Expert opinion: The main target of this review is to present various designing software and 3D manufacturing technologies that have been applied to fabricate facial implants. In doing so, different CAD designing software's are discussed, which are based on various methods and have been implemented and evaluated by researchers. Finally, recent 3D printing technologies that have been applied to manufacture patient-individual implants will be introduced and discussed.

Total Temporomandibular Joint Replacement: Stick to Stock or Optimization by Customization?

Purpose

This article aims to compare the difference in postoperative results in patients treated with either a patient-specific (PSI) or a stock temporomandibular total joint replacement system.

Materials and Methods

The investigators performed a systematic review concerning postoperative results after placement of either a stock total joint replacement system or a PSI. PubMed Central, Web of Science, Cochrane Library Plus, Wiley Online Library, and EMBASE were used to conduct this search. All articles up to August 15, 2018, were scrutinized. All included articles were nonrandomized cohort studies. Maximal mouth opening (MMO) and Visual Analog Scale (VAS) scores for pain and diet before and after surgery were evaluated. The Methodological Index for NonRandomized Studies scale was used for quality assessment. Weighted mean difference was calculated and pooled by meta-analysis using random-effect models.

Results

The search identified 1581 articles, of which 15 were included. The average risk of bias was low. Both systems achieved significant increases in MMO and decreased VAS pain scores at 1, 2, and 3 years after surgery. No significant difference was found between the system types. Both achieved significant improvements in dietary VAS scores, with a more significant improvement for stock implants.

Conclusions

Due to the lack of detailed diagnostic evaluation tools allowing proper start-point categorization, there is a significant risk for selection bias in the pooled data. The PSI is more frequently chosen for cases with more significant joint degeneration, skewing postoperative results. A patient-fitted implant can provide significant operative and patient-centered advantages over a stock implant, which will likely be confirmed when observational cohort studies have included indications like the ones for stock prostheses. Furthermore, while current US Food and Drug Administration-approved stock implants contain cobalt -chromium -molybdenum, the newly manufactured PSI are made of titanium alloy, diminishing the risks of morbidity and implant failure.