A prospective, single-centre study on patient outcomes following temporomandibular joint replacement using a custom-made Biomet TMJ prosthesis

Effect of duration of preoperative pain on outcomes of total temporomandibular joint replacement

The purpose of the study was to determine whether the duration of preoperative pain affects outcomes of temporomandibular joint replacement (TMJR). Twenty-seven patients who underwent primary TMJR between 1 July 2020 and 31 October 2022 were retrospectively assessed for duration of preoperative pain, level of preoperative and postoperative pain on a visual analogue scale (VAS; 0, none; 10, severe), preoperative and postoperative range of motion (ROM), and net change in quality of life (much better, better, same, worse, much worse), reporting the longest available follow up for each patient. Surgical success was defined as postoperative pain of ≤4 and postoperative ROM of ≥30 mm, or net change (Δ) in ROM of ≥10 mm. Regression analyses evaluated associations between independent variables and postoperative pain and ROM. At a mean follow-up of 17.8 (SD: 6.8, range 3-32) months , pain (5.1, SD: 2.2, p < 0.001) and ROM (9.3 mm, SD: 8.0, p<0.001) significantly improved. Quality of life was much better in 16 patients, better in eight, the same in one, and worse in two. Longer duration of preoperative pain tended to be negatively associated with postoperative ROM (β = -0.27; 95% CI -0.6 to 0.0; p = 0.078) but was not associated with severity of postoperative pain. Surgical success was achieved in 23/27 patients. The successful group tended to have lower pain on VAS preoperatively (5.9, SD: 1.9) vs 7.5, SD: 1.3) and postoperatively (0.4, SD: 0.8 vs 4.8, SD: 2.6), and greater improvement in quality of life (much better: 14/23 vs 2/4). In conclusion, longer duration of preoperative pain tended to be associated with worse postoperative ROM following TMJR. Higher preoperative pain may be a predictor for unsuccessful surgery.

Interpositional arthroplasty using cartilage allografts for treating temporomandibular joint arthrosis: a 3- and 5-year retrospective clinical follow-up study

OBJECTIVE

To evaluate the effect of arthroplasty using interpositional cartilage allografts in patients with temporomandibular joint (TMJ) arthrosis.

STUDY DESIGN

This retrospective study included patients treated consecutively between 2007 and 2013 using discectomy and interpositional grafting with lyophilized costal cartilage allograft (Tutoplast) sheets. TMJ pain based on the visual analogue scale (VAS), maximal interincisal opening (MIO), joint tenderness to palpation, crepitus from the affected joint, and postoperative complications were assessed.

RESULTS

Arthroplasty was performed on 37 joints among 34 patients (28 women; mean age: 54 years); 24 joints underwent simultaneous condyle shaving. At final follow-up (3 [n = 37] or 5 [n = 21] years), we observed reduced mean VAS (from 7.6 to 0.9; P < .001) increased mean MIO (from 32.5 to 41.1 mm; P < .001), number of joints with capsule tenderness (from 30 to 3; P < .001), and percentage of joints with crepitus (from 97% to 75%; P = .008). One joint required reoperation because of interposed cartilage fragmentation. No permanent facial nerve injury or malocclusion occurred after treatment.

CONCLUSIONS

Interpositional arthroplasty is a relatively simple, moderately invasive, and effective surgical treatment for TMJ arthrosis with few complications. However, long-term outcomes of this treatment, specifically beyond 3-5 years postoperatively, remain unknown.

Surgical Treatment of Temporomandibular Joint Ankylosis: our experience with 36 cases

AIM

To evaluate and compare outcomes of patients with temporomandibular joint ankylosis (TMJA) treated by gap arthroplasty, costochondral graft, and total alloplastic joint reconstruction.

METHODOLOGY

A retrospective cohort study reviewed and analyzed data from patients with TMJA from January 1, 2009 to December 31, 2019, at the Maxillofacial and Oral Surgery Department, University of the Witwatersrand. Patients with TMJA were treated either with gap arthroplasty, costochondral graft, or total alloplastic joint reconstruction. Data collected included age, sex, etiology of ankylosis, sides involved, preoperation and postoperation mouth opening (MO), treatment type, complications, and revision surgery. Patients were followed up for at least 18 months after the surgical procedure. Comparison of means across the treatment groups was analyzed using paired t tests or analysis of variance test. A P value of less than 0.05 was considered statistically significant.

RESULTS

The study sample comprised of 36 patients [bilateral, n=22; unilateral, n=14 (21 male, 15 female)]. Trauma was the most common etiology (n=27, 75%), followed by chronic infections (n=4, 11.11%) and juvenile arthritis (n=3, 8.3%). A paired t test revealed no statistical significance between treatment modality and postoperative MO and complications over 18 months (P=0.5316 and P=0.426, respectively). The mean MO increased from 4 to 28 mm. Reankylosis was the most common complication (n=5).

CONCLUSIONS

All 3 treatment options yield acceptable outcomes in patients with TMJA. Irrespective of surgical technique, early postoperative exercises, active physiotherapy, and follow-up are imperative for successful rehabilitation and prevention of reankylosis.

Did temporomandibular gap arthroplasty with temporalis interpositional flap improve function and pain in patients with end-stage joint disease? A 5-year retrospective follow-up

The primary aim of this study was to investigate whether patients with end-stage temporomandibular joint (TMJ) disease treated with gap arthroplasty with temporalis interpositional flap (GAT) had improved maximal interincisal opening (MIO) and TMJ pain in a long-term perspective. All patients with severe osteoarthritis, or fibrous or bony ankyloses, and subjected to GAT between 2008 and 2015 were included. The criteria of treatment success were TMJ pain VAS score ≤4 and MIO ≥30 mm. Reoperation was considered as a failure. Forty-four patients (mean age 47 years) were included in this retrospective descriptive case series and followed up for up to 7 years (mean 4.5). Comorbidities were frequent (n = 34) and most commonly rheumatic disease (n = 17). The indications for surgery were ankylosis (n = 32) or severe osteoarthritis (n = 12). Of the 44 included patients, 84% (n = 37) had a history of earlier TMJ surgery. The preoperative mean values for TMJ pain and MIO (VAS 7 and 23 mm, respectively) changed significantly (p < 0.001) to postoperative means of VAS 3 and 34 mm, respecitvely. The success rate was 59% (n = 26). When compared with a previous 2-year follow-up, the success rate was found to have decreased over time (p = 0.0097). The rate of successful treatment outcome in terms of MIO alone was 82% (n = 36). The most common reason for treatment failure was residual pain. In conclusion, the success-rate after GAT did not show long-term stability and continued to drop over time in this patient cohort. TMJ pain seems to be the main reason for failure.

Survival of temporomandibular total joint replacement: A systematic review and meta-analysis

BACKGROUND

Prosthetic total joint replacement has been incorporated as a treatment for complex temporomandibular disorder; however, the survival of those devices is unknown.

OBJECTIVE

To assess the survival rate of the total temporomandibular joint (TMJ) prothesis and their main causes of failure.

METHODS

An electronic search was conducted in eight databases until March 2023. Prospective studies reporting the survival rate of total TMJ prothesis with a minimum follow-up of 12 months were included. Studies with partial TMJ prostheses or those no longer available on the market were excluded. Two reviewers assessed the individual risk of bias using the JBI Systematic Reviews for Quasi-experimental studies tool. Meta-analysis of proportions was conducted to summarise the survival rate, using 95% confidence intervals (CI). The GRADE approach assessed the certainty of the body of evidence.

RESULTS

Data from 320 patients were collected from six prospective studies. The number of prothesis losses varied from none to four. All studies presented sources of bias related to follow-up description of the patients. The follow-up time varied from 12 months to 21 years. In most of the studies, prosthesis failure occurred within the first 6 months after surgery due to infection. The overall survival of total TMJ protheses was 97% (95% CI: 95%; 99%), with low heterogeneity (I2  = 29%) and a very low certainty of evidence.

CONCLUSION

TMJ total prosthesis apparently is a safe procedure with a high survival rate and the evidence is very uncertain and presents important sources of bias.

Virtual Surgical Planning for Temporomandibular Joint Reconstruction with Stock TMJ Prostheses: Pilot Study

The temporomandibular joint (TMJ) is one of the most complex joints in the human anatomy. In advanced degenerative stages, conservative or minimally invasive surgical therapies have failed to restore joint function, and joint replacement with prostheses has been required. Stock prostheses, compared to custom-made prostheses, are much less expensive and require less pre-operative preparation time. Four patients followed for years for temporomandibular dysfunction and previously operated on by arthroscopy or open joint surgery that have been reconstructed with stock TMJ prostheses (STMJP) through virtual surgical planning (VSP) and an STL model with surgical and positioning guides were included. The median follow-up was 15 months; the median number of previous TMJ surgeries was 2. The mean preoperative MIO was 24.6 mm and at longest follow-up was 36.4 mm. The median preoperative TMJ pain score was 8, and the median postoperative TMJ pain was 3. All patients have improved their mandibular function with a clear improvement of their initial situation. In conclusion, we believe that stock TMJ prostheses with virtual surgical planning and surgical guides are a good alternative for TMJ reconstruction at the present time. Nonetheless, prospective and randomized trials are required with long-term follow up to assess their performance and safety.

Customised Implant for Temporomandibular Joint: New Technique to Design and Stress Analysis to Balance the Loading at Both Ends

The temporomandibular joint (TMJ) is a critical joint for the opening and closing of the mouth. The generation of customised TMJs according to individuals' dental anatomy is needed. Currently, the implants available on the market lack consideration of the patient's dental anatomy. This leads to the creation of an imbalance in the reaction forces on both ends of the TMJ. This requires a slight structural change in the design parameters to give a solution. The purpose of this study is to propose a new design that includes the geometry and materials for a TMJ implant. Stress analysis was carried out on the TMJ to balance the reaction forces at both TMJ ends. A static analysis was performed using ANSYS Workbench, to compare the results of two customised designs of TMJ implants, in order to better balance the reaction forces at both ends. The model in the study showed that the reaction forces for both the patient-specific TMJ implants were nearly balanced. The reaction forces were better balanced, and almost equivalent to the intact conditions. The stresses in the mandible were more uniformly distributed in the customised design of the TMJ implant. The two types of design showed that the custom design took up less space in the patient's region of surgery, making it a better option compared to a stock TMJ implant. The custom implant would allow faster patient rehabilitation, as the reaction forces would be close to those in intact conditions.

Concomitant Temporomandibular Joint Replacement and Orthognathic Surgery

The treatment of patients with severe temporomandibular joint (TMJ) disorders and associated skeletal discrepancies presents a complex challenge for oral and maxillofacial surgeons. It is widely recognized that TMDs can impact the stability and outcomes of surgical treatments for dentofacial deformities. Consequently, addressing TMDs prior to or in conjunction with orthodontic or surgical interventions may be necessary to achieve optimal and long-lasting results. Alloplastic temporomandibular joint replacement (TMJR) and orthognathic surgery have emerged as the standard approach due to their predictability, long-term stability and excellent outcomes when addressing end-stage TMJ disease in conjunction with DFDs as it provides a comprehensive solution to address both functional and aesthetic aspects of these patients' conditions. Understanding the appropriate utilization of TMJR in conjunction with orthognathic surgery can lead to improved treatment planning and successful outcomes for patients with complex TMJ disorders and associated dentofacial deformities. This review aims to discuss the indications, preoperative evaluation, staging, sequencing, and surgical considerations involved in utilizing alloplastic TMJ replacement in the presence of dentofacial deformities.

Is the risk of chronic pain after total temporomandibular joint replacement independent of its indications? A prospective cohort study

Chronic pain is a possible long-term complication after alloplastic temporomandibular joint reconstruction (TMJR). This study was developed to evaluate various subjective and objective measurements to determine the presence and degree of TMJ pain in patients treated with TMJR regardless of the indication for the operation. A prospective, single-centre study was performed. Data on 36 patients (56 TMJR) were collected preoperatively and at follow up two to three years postoperatively. The primary outcome variable was subjective TMJ pain (none/mild, moderate/severe) at follow up. The predictor variables were objective pressure pain thresholds (PPTs) at the ipsilateral joint(s) and muscle(s), functional parameters (incisal range of motion, maximum voluntary clenching), subjective oral health-related quality of life (OHRQoL), and demographic and surgical variables. The number of patients with moderate/severe pain decreased from 17 preoperatively to 10 at follow up. Self-reported TMJ pain was significantly reduced in the entire group (p = 0.001). Patients with moderate/severe pain at follow up were more restricted in their OHRQoL but did not differ in PPT and functional parameters from the no/mild pain group. Moderate/severe TMJ pain at follow up was associated with unilateral TMJR and more preoperative pain. This study provides preliminary evidence that despite good pain reduction in most patients, persistent pain after TMJR is common and, in rare cases, may even worsen regardless of the original diagnosis. At follow up there was a close relation between OHRQoL and TMJ pain. TMJ pain after TMJR cannot be confirmed by objective measurement methods (PPTs and functional parameters).

Complications of total temporomandibular joint replacement: a systematic review and meta-analysis

The aim of this systematic review was to determine the most prevalent complications resulting from total temporomandibular joint (TMJ) replacement. An electronic search was performed using the Embase, LILACS, MEDLINE (via PubMed), SciELO, Scopus, and Web of Science databases up to June 2022. Prospective and retrospective clinical studies on patients who underwent TMJ replacement were included. Two reviewers performed the study selection, data extraction, and individual risk of bias assessment using the Joanna Briggs Institute Critical Appraisal Tools. The pooled prevalence of each complication was calculated through a proportion meta-analysis using the random-effects model. Twenty-eight studies met the eligibility criteria and were included in the review. All of the eligible studies had a low risk of bias. The results of the meta-analysis revealed that the most prevalent complication was paresis or paralysis of the facial nerve branches (7.8%; 95% confidence interval (CI) 2.6-15.1%, I2 = 94.5%), followed by sensory alterations (1.8%; 95% CI 0.6-4.9%, I2 = 88.8%), heterotopic bone formation (1.0%; 95% CI 0.1-2.5%, I2 = 75.8%), and infection (0.7%; 95% CI 0.1-1.6%, I2 = 22.7%). In conclusion, TMJ replacement has a low prevalence of complications, and most of them can be managed successfully.

An Overview of Clinical Conditions and a Systematic Review of Personalized TMJ Replacement

The temporomandibular joint (TMJ) is a complex structure in the cranio-maxillomandibular region. The pathological changes of the joint cause deficiencies at different levels, making its replacement necessary in some cases. The aim of this article is to analyze the current indications, treatment and criteria, and follow-up using a systematic review and case series. A systematic review was carried out, identifying the indications for the use of a customized TMJ prosthesis and evaluating criteria and validation in the international literature. After review and exclusion, 8 articles were included with a minimum follow-up of 12 months. The age of the subjects was between 18 and 47 years old. In 226 patients, 310 TMJ prostheses were installed, 168 bilaterally and 142 unilaterally. In most of the articles, a good condition in the follow-up was observed, with a reduction in pain and better conditions of mandibular movement and function. TMJ prosthesis and replacement is a protocolized, defined, stable, and predictable procedure. Indications and criteria must be evaluated by specialists and patients related to the pathology involved in TMJ deformity or degeneration. Randomized research with an accurate diagnosis and follow-up is necessary to obtain the best indication for this treatment.

Management of Intraoperative Contamination of the Custom Total Temporomandibular Joint Prosthesis

Management of intraoperative contamination of a custom total temporomandibular joint prosthesis has not been reported in the literature. As this complication is rare, it can be unsettling for the surgeon. Improper management may lead to a complicated treatment course and financial consequences. Prevention is the primary strategy for avoidance and appropriate management is dependent on many variables. The purpose of this report is to identify a unique complication associated with placement of a custom temporomandibular joint prosthesis and offer an algorithm for management.

Functioning of the Masticatory System in Patients with an Alloplastic Total Temporomandibular Joint Prostheses Compared with Healthy Individuals: A Pilot Study

BACKGROUND

Most patients with temporomandibular joint (TMJ) issues are successfully treated with nonsurgical methods. However, when end-stage TMJ pathologies occur, invasive management can be required, such as a total TMJ replacement. This cross-sectional pilot study aimed to provide insight into the functioning of the masticatory system, pain, and patient satisfaction in patients treated with a total joint replacement (TJR).

METHODS

A cross-sectional pilot study was conducted to determine the postoperative clinical results of an alloplastic TJR TMJ. Masticatory performance and also insight into maximum voluntary bite force (MVBF), active and passive maximum mouth opening (aMMO/pMMO), pain, and patient satisfaction were measured. Masticatory performance, MVBF, and aMMO of patients with a TJR TMJ were compared with healthy individuals.

RESULTS

Masticatory performance is equal between patients with a TJR TMJ and healthy individuals, but both MVBF and aMMO were significantly smaller in patients with a TJR TMJ. However, patients had almost no pain and were very satisfied with the TJR TMJ treatment.

CONCLUSION

This study revealed that most patients with an alloplastic TJR TMJ were able to function without pain, showed good masticatory performance, and were highly satisfied with their alloplastic TJR TMJ. However, MVBF and aMMO were lower than in healthy individuals.

Reconstruction of the TMJ and condyle in inflammatory arthritis

Inflammatory arthritis presents a unique destructive process to the temporomandibular joint. This article provides information on the proper diagnosis, treatment planning, and surgical management aimed to provide patients with improvement in pain, function, stability and facial aesthetics. Additionally, it aims to provide a detailed insight on the joint reconstruction options including alloplastic joint replacement, autogenous joint replacement, orthognathic surgery and distraction osteogenesis.

Quality of Life After Total Temporomandibular Joint Prothesis Surgery

INTRODUCTION

Total temporomandibular joint (TMJ) prostheses are increasingly used in patients with joint destruction presenting significant pain and mouth opening limitation. This surgery can be considered as the last resort solution whose goal is to restore the mandible function. The aim of this study was to evaluate the patient quality of life (QoL) before and after TMJ replacement surgery with a total TMJ prosthesis, using a modified QoL scale.

MATERIALS AND METHODS

All patients with a total uni or bilateral TMJ prosthesis who could be contacted were included. All patients completed 2 retrospective questionnaires: once relative to the preoperative QoL and another for the post-operative QoL, including the assessment of mouth opening limitation, daily eating difficulties and also a QoL score, adapted from the TMJ-QoL questionnaire.

RESULTS

A total of 17 patients were included: 13 temporomandibular ankylosis, 3 condylar resorptions and 1 congenital malformation. Mouth opening limitation and daily eating difficulties were significantly reduced after surgery (P < 0.001). Nine of the 11 QoL questions showed a significant decrease in score and thus an improvement of the QoL after surgery: having a conversation (P = 0.006), eating (P < 0.001), yawning (P < 0.001), sleeping (P= 0.043), recreational activities (P = 0.005), relaxing (P= 0.021), feeling depressed because of TMJ problems (P = 0.032), daily activities (P = 0.008) and patient self-assessment of QoL (P = 0.003). Two showed no significant difference: taking analgesics, and social life. Total score of QoL showed a significant improvement (P= 0.003).

CONCLUSIONS

Quality of life, mouth opening, and daily eating were significantly improved after total TMJ prosthesis, in agreement with the litterature. The TMJ prosthesis could be considered ealier in the management of end-stage temporomandibular disease.

Biomechanical Analysis of Patient-Specific Temporomandibular Joint Implant and Comparison with Natural Intact Jaw Bone Using Finite Element Method

The purpose of this study is to design a patient-specific TMJ implant and study its behaviour under different loading conditions compared with natural intact TMJ. There are several diseases, which affect the proper growth and function of TMJ, and in some cases, TMJ injury results from accidents. To repair the TMJ, temporomandibular joint replacement or TJR surgery is performed. In this work, CT-scan data of the skull and mandible region with broken condylar head were used to study the biomechanical behaviour of the intact mandible and customized TMJ prostheses in order to design a patient-specific total TMJ implant. The customized TMJ implant was virtually studied under simulated loading conditions using finite element method (FEM) in ANSYS Workbench and then compared to the intact jaw-mandible for the combinations of two different biocompatible material models. It is observed that the natural TMJ has a higher deformation value as compared to the patient-specific TMJ implant due to the lower mechanical strength of bone relative to the Ti-6Al-4V and Co-Cr alloy. Hence, we can conclude that the designed custom TMJ implant is safe for the patient from the point of design perspective.

Reasons for failure of total temporomandibular joint replacement: a systematic review and meta-analysis

The aim of this study was to evaluate the revision rate after total alloplastic temporomandibular joint replacement (TMJR) and determine whether there is a higher risk of revision surgery with stock or custom-fitted prostheses (the two most current TMJR prosthesis types). A systematic review was performed, with a search of PubMed, Google Scholar, and the Cochrane Library in November 2020. Overall, 27 articles were included in this study, describing Biomet and TMJ Concepts prostheses and including postoperative data on complications requiring a return to the operating room. A total of 2247 prostheses were analysed: 1350 stock Biomet prostheses and 897 custom-fitted TMJ Concepts and custom-fitted Biomet prostheses. The global revision rate was 1.19 per 100 prosthesis-years. The most common reason for revision was heterotopic bone formation. Stock prostheses appeared to have a lower risk of revision compared to custom prostheses: rate ratio 0.52 (95% confidence interval 0.33-0.81, P-value 0.003). Regarding causes of revision, the only significant difference between the types of devices was a higher rate of heterotopic bone formation for custom-made prostheses (P = 0.001). The results of this study revealed a low revision rate post TMJR revision, with stock devices even less prone to such risk. Nevertheless, these results can be explained by the fact that custom-made prostheses are more likely to be used for cases in which the anatomy is significantly abnormal or there is a history of multiple joint surgeries, which carry a greater risk of complications and heterotopic bone formation.

Technical report and rare case description-patient-specific spacer made of bone cement for the revision of a PSI-TMJ fossa after screw fracture

Total alloplastic temporomandibular joint replacement (TMJ-TJR) has once again become the focus of therapy for end-stage destroyed joints. Although material quality has increased significantly in terms of service life and wear, problems occur even with patient-specific (PSI) prostheses. Here, mainly the ramus components are affected and an occurrence of screw loosening or fractures in the area of the fossa of stock joints is rare and has not yet been described for patient-specific (PSI) components. Although very rare, such events pose a great challenge to both practitioners and affected patients, especially in the case of PSI components, not least due to the long time required for new fabrication. The case report shows a non-described screw fracture of a PSI-TMJ fossa and the first description of a temporary revision using a PSI-TMJ fossa made of bone cement.

Reconstruction of bilateral ramus-condyle unit defect using custom titanium prosthesis with preservation of both condyles

BACKGROUND

Novel technologies for management and reconstruction of complex bony defects regarding both function and facial appearance are interestingly used in maxillofacial surgery. In the current study, we demonstrated reconstruction of a bilateral ramus-condyle unit (RCU) defect while preserving both condyles by a novel designed titanium prosthesis using virtual surgical planning (VSP), computer-aided design and manufacturing (CAD/CAM), and Selective Laser Melting (SLM) technologies.

MATERIALS AND METHODS

A 3D customized titanium prosthesis was designed for a 49 -year-old patient with bilateral mandibular aggressive central giant cell granuloma (CGCG) according to mandibular normal anatomy and structure while preserving bilateral intact condyles. Finite element study was performed to investigate the effects of new design strength and the stress shielding phenomenon. The design of macro-pores inside the body of prosthesis allowed it to act as a scaffold for bone tissue engineering under load bearing conditions.

RESULTS

Analysis of the strength and stress shielding phenomenon demonstrated favorable outcomes regarding the novel design. For instance, there was no stress shielding in any of the preserved condyles with regard to the size and distribution of stresses. Also, the stress distribution around the pores showed that these pores had no effect on the strength of the prosthesis. Thirty month follow-ups after reconstruction of bilateral RCU defect showed normal jaw function with a favorable facial appearance and mandibular contour.

CONCLUSION

We design a novel patient-specific prosthesis with desirable biomechanical features for reconstruction of bilateral RCU defect after resection of the benign tumor with preservation of bilateral intact condyles.

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.

Alloplastic Total Temporomandibular Joint Reconstruction: A 10-Year Experience of the University of the Witwatersrand, Johannesburg

AIM

This study aimed to retrospectively analyze our 10-year experience with total alloplastic reconstruction of the temporomandibular joint prostheses. Indications and clinical outcomes were also evaluated.Methodology: This was a cross-sectional study in which 31 patients who had alloplastic total Temporomandibular Joint prosthesis implanted between 2007 and 2017 were reviewed.

OBJECTIVE

Outcomes (maximum mouth opening distance and occlusion), subjective outcomes (pain, diet consistency and chewing, quality of life), and complications were evaluated.

RESULTS

There were 16 females and 15 males with a mean age of 36.94 years (range 11-72 years). In total, 51 prostheses (20 bilateral, 11 unilateral) were implanted. The stock prostheses were used in 28 patients (90.32%) and only 3 (9.68%) were of custom-made type. Fifty-eight percent of patients were diagnosed with temporomandibular joint ankylosis, 22.58% had degenerative conditions, 9.68% had pathology (hemifacial microsomia, synovial chondromatosis, and osteochondroma), and 9.68% had malocclusion.The results showed that there was a significant improvement in maximum mouth opening distance (P-value < 0.0001), particularly in patients who had ankylosis.There was improvement in diet consistency (P-value < 0.0001) and quality of life (P-value 0.013). Postoperative complications ranged from facial nerve injuries (n = 4), keloids (n = 2), and heterotopic bone formation (n = 2).

CONCLUSION

TMJ alloplasts provide satisfactory clinical and functional outcomes for patients with end-stage TMJ diseases, evidenced by overall improvement in maximum mouth opening, chewing ability and quality of life and reduction in pain. Previously operated joints and a preoperative diagnosis of ankylosis increase the risk of occurrence of complications postimplantation of total alloplastic joints.

Predictive risk factors for facial nerve injury in temporomandibular joint replacement surgery

The objective of this study was to determine the prevalence of temporary and permanent facial nerve injury in total temporomandibular joint (TMJ) replacement surgery and to identify potential predictive risk factors. We made a retrospective review of case notes and opportunistic review of patients treated in a single tertiary referral unit by a single surgeon. For each patient a number of potential risk factors were determined, and the presence or absence of nerve injury recorded at 2 week follow up and a minimum of 12 months follow up. At 2-week review, facial nerve weakness was noted in 38/133 cases (28%) and at last follow up there were 4/133 cases (3%) with continuing (permanent) facial nerve weakness. Bilateral surgery, revision TMJ replacement, primary diagnosis, the number of previous surgeries and a history of recovered facial nerve injury all significantly increased the likelihood of temporary facial nerve injury, but not the likelihood of permanent facial nerve injury. Factors which increase the risk of temporary facial nerve injury are relatively predictable and include bilateral surgery, revision TMJ replacement, and multiple open TMJ surgeries. Risk factors associated with permanent injury are less predictable but are likely to be similar. The identification of such factors allows for the risk stratification of patients and improve informed consent. We also recommend that patients with a single, previously failed open TMJ surgery should be considered for early TMJ replacement and in multiply operated patients a subfascial plane of dissection is adopted.

Patient specific total temporomandibular joint reconstruction: A review of biomaterial, designs, fabrication and outcomes

Purpose

The aim of this article was to systematically review the available literature on patient specific total temporomandibular joint total joint replacement (PS-TMJR) implants for their biomaterial, designs, fabrication techniques and their outcomes.

Methods

A literature review was conducted using PubMed, and science direct databases using the key words three-dimensional printing, 3D printing, CAD CAM, computer aided designing, computer aided manufacturing, additive technology, custom made implants, patient specific implants in combination with Temporomandibular joint, TMJ surgery.

Results

The search revealed 2760 articles, of which 374 were in English and discussed TMJ reconstruction. Further filtering shortlisted 74 articles that discussed PS-TMJR. Duplicates were removed and additional added from article references. 39 articles describing biomaterial, designing and fabrication of PS-TMJR implants and their outcomes were selected for analysis.

Conclusions

Although PS-TMJR implants allow a better anatomical fit, improved fixation, and safeguard various structures such as the inferior alveolar nerve, they vary in designs, material and fabrication techniques. However, PS-TMJR printed with SLM and EBM technologies have yet to be compared with the conventional ones in terms of mechanical strength, and clinical outcome. With emerging bioprinting technologies, even newer biomaterials should be considered for 3D printing of PS-TMJR devices designed to achieve harmony in function between the joint device, bone and masticatory muscles.

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.

Clinical and radiological outcomes of Chinese customized three-dimensionally printed total temporomandibular joint prostheses: A prospective case series study

PURPOSE

Temporomandibular joint (TMJ) diseases are highly prevalent in China. However, no commercialized custom-made prostheses are available now. This study introduces a three-dimensionally (3D) printed customized total TMJ prosthesis manufactured by a standardized workflow.

MATERIALS AND METHODS

Consecutive patients with end-stage TMJ diseases were recruited from Jan 2018 to Sep 2018. The computed tomography (CT) data for patients were obtained and transformed into the Mimics 18.0 software preoperatively for designing of prostheses and digital templates. 3D printing, friction spot welding and computer-assisted manufacture (CAM) were used to fabricate different components of the prosthesis. The clinical and radiographic evaluations were performed postoperatively.

RESULTS

A series of 9 patients were included. All the prostheses were placed smoothly and fixed stably during surgical procedure. Without severe postoperative complications, all patients exhibited significant improvements in maximum mouth opening, pain, diet, and mandibular function, with good facial symmetry. For the whole prosthesis, the average mean deviation was 0.432 mm (range: from 0.279 to 0.561 mm).

CONCLUSIONS

This study suggests that Chinese customized 3D-printed total TMJ prostheses produces excellent short-term clinical outcomes, with high accuracy in implantation.

Protocol for fully digital and customized management of concomitant temporomandibular joint replacement and orthognathic surgery

End-stage temporomandibular joint (TMJ) disease is caused by a multitude of pathological processes that impair TMJ anatomy and function. In many cases, end-stage TMJ disease and dentofacial skeletal deformities coexist. The optimal treatment for such conditions is total alloplastic joint replacement and orthognathic surgery. Such procedures have historically been conducted in two separate stages. Furthermore, while technological improvements resulting from the widespread adoption of virtual reality initially led to significant improvements in the field of orthognathic planning, the adoption of virtual design techniques to optimize TMJ reconstruction was a later achievement. Therefore, planning for TMJ replacement and orthognathic surgery did not develop in parallel, leading to various combinations of planning for orthognathic surgery and TMJ replacement with the aim of performing both procedures simultaneously in one stage. Nowadays, improvements in virtual planning and three-dimensional printing have allowed these procedures to be conducted in the same surgical step based on fully digital planning and entirely customized surgery. This paper introduces a fully digital protocol for the treatment of end-stage TMJ disease and associated acquired dentofacial deformities, in which all surgical steps are customized and the whole surgery is performed in succession using automated procedures, thanks to the combined use of virtual surgical planning, surgical guides, custom-designed TMJ prostheses, and patient-fitted osteosynthesis devices.

Evaluation of complications following stock replacement of the temporomandibular joint performed between the years 2006 and 2015: a retrospective study

PURPOSE

Alloplastic total temporomandibular joint replacement (TMJR) is now considered to be a standard procedure for temporomandibular joint (TMJ) reconstruction. TMJR can improve mandibular mobility, restore the dental occlusion and improve facial aesthetics. The purpose was to assess the presence of intraoperative and post-operative complications, including the presence of post-operative chronic pain.

METHODS

This retrospective study evaluated the use of 62 stock TMJR devices implanted in 45 patients who underwent surgery between the years 2006 and 2015 by the same surgeon at the Department of Oral and Maxillofacial Surgery, Stomatology Clinic, General Teaching Hospital (VFN) Charles University, Prague, Czech Republic.

RESULTS

Intraoperative and post-operative complications recorded were facial nerve dysfunction (14-22%), open bite/malocclusion (2-3.2%), condylar component dislocation (1-1.6%), infection requiring revision surgery (1-1.6%) and (27-43%) reported chronic pain 24 months after surgery.

CONCLUSIONS

As with any surgical procedure, TMJR can have complications. The results of this study demonstrate that the most common post-operative complication was continued pain. Chronic pain after TMJR was more common in patients with a preoperative diagnosis of degenerative joint disease. Also, the incidence of post-operative TMJR pain increased with the duration of symptoms prior to TMJR, leading to a question of the best timing for TMJR.

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.

Total joint reconstruction using computer-assisted surgery with stock prostheses for a patient with bilateral TMJ ankylosis

Backgrounds

The purpose of this study is to discuss the total joint reconstruction surgery for a patient with recurrent ankylosis in bilateral temporomandibular joints (TMJs) using three-dimensional (3D) virtual surgical planning, computer-aided manufacturing (CAD/CAM)-fabricated surgical guides, and stock TMJ prostheses.

Case presentation

A 66-year-old female patient, who had a history of multiple TMJ surgeries, complained of severe difficulty in eating and trismus. The 3D virtual surgery was performed with a virtual surgery software (FACEGIDE, MegaGen implant, Daegu, South Korea). After confirmation of the location of the upper margin for resection of the root of the zygoma and the lower margin for resection of the ankylosed condyle, and the position of the fossa and condyle components of stock TMJ prosthesis (Biomet, Jacksonville, FL, USA), the surgical guides were fabricated with CAD/CAM technology. Under general anesthesia, osteotomy and placement of the stock TMJ prosthesis (Biomet) were carried out according to the surgical planning. At 2 months after the operation, the patient was able to open her mouth up to 30 mm without complication.

Conclusion

For a patient who has recurrent ankylosis in bilateral TMJs, total joint reconstruction surgery using 3D virtual surgical planning, CAD/CAM-fabricated surgical guides, and stock TMJ prostheses may be an effective surgical treatment option.

Ex-vivo and in vitro validation of an innovative mandibular condyle implant concept

PURPOSE

The purpose of this study is to pre-validate an inovative implant concept, and to compare the behavior of the mandibular condyle against a commercial Biomet implant in an ex vivo model and present results of the first cadaveric studies.

MATERIALS AND METHODS

Three experimental cadaveric condyles were tested under three conditions: one intact, another with the Biomet model, and one with the innovative concept. The condyle was tested with a reaction of 300 N in all situations and the principal strains were measured. Before the geometry of the cadaveric condyle was reconstructed from a microCT scan, and a finite element model was created. Finally, a procedure was carried out with the new implant by two expert surgeons on a two cadaveric head model.

RESULTS

In vitro the mandible condyle presents a linear behavior until maximum load. The strain measured with Biomet implant indicates a strain shielding effect in the proximal region, inducing bone loss in the long term. The lingual side of the Biomet implanted condyle presents an increase of +44% in strain.

CONCLUSION

The new concept was evaluated and showed a similar behavior to the intact model, and better behavior than the Biomet. The innovative concept proves that it is possible to avoid screws for a TMJ fixation and improve the TMJ alloplastic behavior.

Biomechanical evaluation of Chinese customized three-dimensionally printed total temporomandibular joint prostheses: A finite element analysis

PURPOSE

This work aims to evaluate the biomechanical behavior of Chinese customized three-dimensional (3D)-printing total temporomandibular joint (TMJ) prostheses by means of finite element analysis.

METHODS

A 3D model was established by Mimics 18.0, then output in a stereolithography (STL) format. Two models were established to investigate the strain behaviors of an intact mandible and a one-side implanted mandible respectively. Hypermesh and LS-DYNA software were used to establish computer-aided engineering finite element models. The stress distribution on the custom-made total TMJ prosthesis and the strain distribution on the mandible were analyzed by loading maximal masticatory force.

RESULTS

The maximum stress on the surface of the ultra-high-molecular weight polyethylene was 19.61 MPa. With respect to the mandibular component, the maximum stress in the mandibular component was located at the anterior and posterior surface of the condylar neck, reaching 170.01 MPa. The peak von Mises stress was observed on the topside screw of the mandible, which was found to be 236.08 MPa. For the intact model, it was observed that the strain distribution was basically symmetrical. For the model with the prosthesis, the curve of strain distribution was fundamentally consistent with that in the intact mandible, except for the last 24 mm along the control line. A prominent strain decrease between 41.4% and 58.3% was observed in this area.

CONCLUSIONS

Chinese customized 3D-printed total TMJ prostheses exhibit uniform stress distribution without changing the behavior of the opposite side natural joint. Furthermore, the prostheses have a great potential to be improved in design and materials with a promising future.

Costochondral Graft Versus Total Alloplastic Joint for Temporomandibular Joint Reconstruction

Presently, there are 2 options for the replacement of the temporomandibular joint for end-stage pathology: autogenous bone grafting or alloplastic joint replacement. This article presents evidence-based advantages and disadvantages for each of these management options to assist both surgeons and their patients in making that choice.

Temporomandibular joint reconstruction

PURPOSE OF REVIEW

Temporomandibular joint (TMJ) reconstruction represents one of the more challenging clinical problems that a head and neck surgeon encounters. Fortunately, the problem is fairly uncommon; however, at the same time, clear clinical guidelines have not been formulated. The goal of this review is to present the established solutions to this difficult reconstructive challenge and highlight key developments that have been recently published.

RECENT FINDINGS

Modern-day approaches to TMJ reconstruction include a handful of surgical modalities: costochondral grafting, revascularized tissue transfer, distraction osteogenesis, and alloplastic temporomandibular joint replacement (APTMJR). Over the past several years, publications have focused primarily on distraction osteogenesis and APTMJR. In particular, APTMJR is emerging as a highly successful and versatile surgical modality when faced with TMJ defects.

SUMMARY

With long-term follow-up after APTMJR approaching 20 years at several of the pioneering centers, alloplastic total joint replacement is emerging as the clinical standard when faced with TMJ defects in a variety of clinical situations. Unfortunately, the dogma of serious complications that occurred during early development may still be stalling widespread acceptance of APTMJR. Due to the complexity of the surgery, its relative infrequency and the lack of exposure in the majority of residency training programs, this surgery is currently best performed by tertiary referral centers.

An unusual osteoma in the mandibular condyle and the successful replacement of the temporomandibular joint with a custom-made prosthesis: a case report

Background

An osteoma is a benign tumor of bone with unknown etiology and is considered rare, mostly restricted to the craniofacial skeleton.

Case presentation

This case report describes an uncommon condylar osteoma in a 67 years old white female patient with laterognathism to the left side, limited mouth opening, aesthetic change and pain associated with the right temporomandibular joint (TMJ). The histopathological examination confirmed osteoma. The lesion was surgically excised and immediate reconstruction was carried out using a custom-made total TMJ prosthesis. The patient has been in follow-up for 2 years, with no symptoms.

Conclusions

Unilateral total TMJ prosthesis can be considered to replacement of TMJ after osteoma excision with resection of the condyle.

Fibrous condylar dysplasia: Resection and reconstruction with a custom-made TMJ prosthesis using virtual surgical planning

The main objective of this article is to describe the indications for custom-made alloplastic reconstruction of the temporomandibular joint (TMJ) using the new techniques of virtual surgical planning and computer-aided design/computer-aided manufacturing (CAD/CAM) technology through the study of a clinical case and an updated review of the literature. The patient was a 45-year-old male with a fast-growing condylar dysplasia that produced a progressive facial deformity with limited mandibular mobility, which required a radical resection. Predictable, satisfactory, and stable results over time are described from the aesthetic, functional, and symptomatic points of view, through a comprehensive approach to all the aspects of this case by following an appropriate line of development and using the most current techniques.