A two-stage procedure for temporomandibular joint disc replacement using free pericranial grafts: a preliminary report

Microstructural and Micromechanical Properties of Decellularized Fibrocartilaginous Scaffold

Fibrocartilage decellularized extracellular matrix (dECM) is a promising alternative material for damaged fibrocartilage repair and replacement due to its biomimetic gross morphology and internal microstructure. However, the alterations in the microstructure and micromechanical properties of fibrocartilage after decellularization interfere with the macroscopic functional application of the scaffold. Therefore, this study aims to present an analytical atlas of the microstructure and micromechanics of the fibrocartilaginous dECM scaffold to elucidate the effect of decellularization treatment on the macroscopic function of the scaffold. The fibrocartilage dECM was prepared using the temporomandibular joint (TMJ) disc as the model, and its durability was evaluated under three functional states (physiological, physiological limit, and beyond the limit). The macroscopic function of different fibrocartilage dECM exhibits notable differences, which are attributed to the destruction of the multilevel collagen structure. This process involves unwinding triple-helix tropocollagen molecules, destroying collagen fibril D-periodicity, expanding collagen fiber bundle curling, and loosening of the collagen fiber network. The impairment of multiscale collagen structures degrades the cross-scale mechanical modulus and energy dissipation of dECM from the triple helix molecules to the fibril level to the fiber bundle that extends to the fiber network. This study provides important data for further optimizing decellularized fibrocartilage scaffolds and evaluating their translational potential.

Applications of hydrogels in tissue-engineered repairing of temporomandibular joint diseases

Epidemiological studies reveal that symptoms of temporomandibular joint disorders (TMDs) occur in 60-70% of adults. The inflammatory damage caused by TMDs can easily lead to defects in the articular disc, condylar cartilage, subchondral bone and muscle of the temporomandibular joint (TMJ) and cause pain. Despite the availability of various methods for treating TMDs, few existing treatment schemes can achieve permanent recovery. This necessity drives the search for new approaches. Hydrogels, polymers with high water content, have found widespread use in tissue engineering and regeneration due to their excellent biocompatibility and mechanical properties, which resemble those of human tissues. In the context of TMD therapy, numerous experiments have demonstrated that hydrogels show favorable effects in aspects such as articular disc repair, cartilage regeneration, muscle repair, pain relief, and drug delivery. This review aims to summarize the application of hydrogels in the therapy of TMDs based on recent research findings. It also highlights deficiencies in current hydrogel research related to TMD therapy and outlines the broad potential of hydrogel applications in treating TMJ diseases in the future.

Decellularized-disc based allograft and xenograft prosthesis for the long-term precise reconstruction of temporomandibular joint disc

Currently, no effective disc reconstruction treatment strategy is clinically available for temporomandibular joint (TMJ) disc-related diseases. To address this, we developed a prosthesis construct with laser-drilled decellularized natural disc reinforced by polycaprolactone, which mimics the natural morphology, and structural, biomechanical and biological property of the TMJ disc. The construct demonstrated good biocompatibility, safety and immunological tolerance both in vitro, and in a rat subcutaneous model. During 6 months implantation in an allogeneic rabbit TMJ disc reconstruction model, the disc prosthesis maintained its integrity, collagen fiber-orientation, mechanical property, joint structural stability and prevented articular cartilage and bone from damage. Furthermore, the "upgraded" disc prosthesis obtained from decellularized porcine disc was implanted into a goat TMJ disc reconstruction model. The xenograft prosthesis, with strength and viscoelasticity similar to a natural TMJ disc, was able to restore the structure and function of TMJ up to 20 weeks. These results demonstrate the translational feasibility of an allogeneic or xenogeneic decellularized disc prosthesis for treatment of advanced TMJ disc-related diseases. STATEMENT OF SIGNIFICANCE: This study makes a significant contribution to TMJ disc disease treatment both in theory and in clinics, because: (1) it provided an innovative approach to prepare an artificial TMJ disc with decent mechanical properties and long-term condyle-protecting effect; (2) it specified an advanced decellularized method for fibrocartilage decellularization and xenograft application; (3) it developed a facile and reproducible TMJ disc reconstruction model not only for middle size animal but also for large animal study; (4) the comprehensive and unreported biomechanical tests on the natural TMJ discs would act as a valuable reference for further research in the field of artificial TMJ disc materials or TMJ disc tissue engineering; (5) it suggested a potential treatment for patients with severe TMJ diseases that were commonly met but difficult to treat in clinics.

3D-Printed Polycaprolactone Reinforced Hydrogel as an Artificial TMJ Disc

The replacement of a damaged temporomandibular joint (TMJ) disc remains a long-standing challenge in clinical settings. No study has reported a material with comprehensively excellent properties similar to a natural TMJ disc. In this work, we designed a novel artificial TMJ disc using polyvinyl alcohol (PVA) hydrogel crosslinked by cyclic freeze-thaw and reinforced by 3D-printed polycaprolactone (PCL) implants. The mechanical properties and surface morphologies of the artificial TMJ disc and the natural goat TMJ disc were tested and compared via compression, tensile, cyclic compression/tensile, creep, friction, scanning electron microscopy, and atomic force microscopy. The fibroblasts and chondrocytes were cultured on the artificial TMJ disc for 1, 3, and 5 d for cytotoxicity testing. Importantly, the artificial discs were placed into the TMJs of goats in an innovative way to induce disc defect repair for 12 wk. The PVA + PCL artificial disc demonstrated mechanical strength similar to that of natural disc, as well as 1) better fatigue resistance, viscoelasticity, and hydrophilicity; 2) less creep; and 3) low friction, cytotoxicity, and cell adhesion. By repairing the defects of the TMJ disc in goats, the artificial disc demonstrated the ability to maintain joint stability and protect condylar cartilage and bone from damage. These promising results indicate the feasibility of using a PVA + PCL artificial TMJ disc in a clinical context.

Clinical assessment of acellular dermal matrix (AlloDerm©) as an option in the replacement of the temporomandibular joint disc: A pilot study

BACKGROUND

There is limited data available in the literature describing the utility of acellular dermal matrix (AlloDerm©) in the replacement of the temporomandibular joint disc. Few reports of clinicians using implantable AlloDerm to replace the disc do exist, however, this has been described for reconstruction after surgical resection of the entire temporomandibular joint complex to treat pathology, as opposed to isolated articular disc disorders. Moreover, there is a lack of description in the literature regarding associated perioperative outcomes after such a procedure. We sought to assess the immediate perioperative outcomes in the form of a pilot study, to determine whether this technique warrants further investigation in the form of prospective clinical studies.

METHODS

The study team conducted a retrospective review of medical records for patients who underwent temporomandibular joint discectomy and replacement with AlloDerm© at a single tertiary care center, from 2011 to 2016. Perioperative outcomes of interest including pain levels and range of motion were recorded and descriptive statistics were utilized for statistical analysis.

RESULTS

15 patients met the inclusion criteria, of which 87% were females and 13% males. The mean age was 47.27±15.93 years. Preoperatively, 74% of the patients reported severe pain (VAS scores of 7-10); in contrast, 73% of the patients reported only mild pain (VAS scores of 1-3) during the postoperative visits, suggesting an overall reduction in pain intensity. Range of motion also improved from an average of 27.73±13.04mm, to an average of 38.60±6.08mm (P<0.01).

CONCLUSIONS

Based on our preliminary data, patients with advanced TMJ articular disc disorders showed clinical improvement from discectomy and replacement with acellular dermal matrix (AlloDerm©). Further longitudinal studies evaluating long-term outcomes need to be conducted to validate this technique, in the form of larger sample sizes with a control group, as well as radiographic assessment of long-term clinical outcomes.

Surgery of temporomandibular joint under local anaesthesia

Temporomandibular joint ankylosis is a debilitating disorder arising from an inability to open the mouth. This leads to poor nutrition, poor dental hygiene, and stunted growth. Anaesthesia, especially general anaesthesia, is very difficult to administer. There is a lack of direct visualization of the vocal cords, tongue fall following relaxation, and an already narrowed passage due to a small mandible, which makes even the blind nasal intubation difficult. There are various techniques described in literature to overcome these challenges, failing which, one needs to do tracheostomy. All the risks of difficult intubation and general anaesthesia can be avoided if the surgery is done under local anaesthesia. A simple but effective method of successful local anaesthesia is described, which allows successful temporomandibular joint reconstruction.

Morphologic and immunohistochemical observation of explanted Proplast-Teflon temporomandibular joint interpositional implants

PURPOSE

The objective of this study was to investigate the cellular tissue response to temporomandibular joint (TMJ) Proplast-Teflon disc material by morphologic and immunohistochemical means.

PATIENTS AND METHODS

Twelve patients who had been subjected to TMJ discectomy combined with insertion of a Proplast-Teflon interpositional implant (PTIPI) were recalled for removal of the alloplastic disc. The time elapsed between the Proplast-Teflon disc implantation and its removal varied between 13 and 71 months (mean, 54.6 +/- 5.8 [SEM]) The implants and periimplant tissues were examined by light microscopy and immunohistochemically using a panel of monoclonal antibodies reactive with different subclasses of leukocytes. The sections were immunostained using the alkaline phosphatase-antialkaline phosphatase (APAAP) technique.

RESULTS

Fibrosis and a massive foreign body giant cell reaction were seen inside the heavily disrupted alloplastic implants and in the periimplant tissues. CD68-positive monocyte-derived cells dominated the reactive infiltrate in the implants and surrounding tissue. The CD68-positive cells also were partly positive for lysozyme. The lymphocytic infiltration contained no B cells.

CONCLUSIONS

This study of the PTIPI-induced tissue reaction gave no indication of a toxic or an immunologic pathogenesis. Mechanical stress seems important in the fragmentation of the implant and induction of the foreign body reaction. It is not yet known if this fragmentation is the major contributing factor.

Reconstruction of the temporomandibular joint using a temporalis graft with or without simultaneous orthognathic surgery

PURPOSE

This article reports the outcome of free temporalis fascia and muscle graft (TFG) reconstruction of the temporomandibular joint (TMJ) with and without simultaneous orthognathic surgery (SOS).

MATERIALS AND METHODS

Twenty-nine patients (45 joints) were evaluated retrospectively. Group 1 consisted of 17 patients (16 women 1 man) and 30 joints. Fifteen (88%) patients had sagittal split ramus osteotomies (SSRO); 8 (53%) of these patients also had Le Fort I osteotomies, and 2 patients (12%) had only Le Fort I osteotomies with TFG. Group 2 consisted of 12 patients (15 joints) who received only TFG and no SOS.

RESULTS

Group 1 had 9 patients (53%) with an incisal opening greater than 35 mm, 11 joints (37%) with greater than 6 mm lateral excursive movement, and 11 patients (65%) were asymptomatic postoperatively. Average follow-up was 57.4 months (range, 23 to 69 months). Group 2 had eight patients (67%) with an incisal opening greater than 35 mm, six joints (40%) with greater than 6 mm lateral excursive movement, and seven patients (58%) were asymptomatic postoperatively. Average follow-up was 55.1 months (range, 48 to 64 months).

CONCLUSION

TFG with and without SOS produced similar treatment outcomes in comparing groups 1 and 2. No significant differences were observed for the number of patients with an incisal opening > 35 mm (P = .703), lateral excursion > 6 mm (P = 1.00), and successful elimination of pain (P = 1.00), even though group 2 had a significantly greater number of patients (P < 0.01) that were operated on unilaterally. Combining treatment outcomes for both groups, the number of previous joint surgeries significantly affected success (P < .01). The presence of osteoarthritic changes did-not significantly affect treatment outcome (P = .187).

Unusual complication of temporomandibular joint surgery: cervicomediastinal abscess

Cervicomediastinal abscess developed in a 14-year-old girl after temporomandibular joint surgery. No such complication could be found in the literature. The complications of temporomandibular joint surgery and the possible ways this abscess may have developed are discussed.

The Christensen prosthesis. A retrospective clinical study

The objective of this study was to determine if the Christensen temporomandibular joint prosthesis system in an effective alternative in treating patients with severe temporomandibular joint disorders. A total of 69 patients who were not responsive to either nonsurgical or prior surgical treatments were placed into one of three treatment groups depending on the following diagnoses: (1) placement of a glenoid fossa-eminence prosthesis with meniscus retention (22 patients, 40 joints); (2) placement of a glenoid fossa-eminence prosthesis without retention of the meniscus (26 patients, 49 joints); (3) total joint replacement (21 patients, 34 joints). Patients were evaluated immediately before surgery and at regular intervals after surgery for an average of 3.1 years. Success was measured as a significant improvement of function and decrease in pain as measured on a visual analogue scale, as well as improved incisor opening as measured with a Therabite Scale (Lorenz Surgical, Jacksonville, Fla.). Comparison of mean and average pre- and postsurgical values for all groups and criteria showed significant improvement. Results of this study indicate that the Christensen temporomandibular joint prosthesis system may offer a viable method for the treatment of severe temporomandibular joint disease with a high degree of success.

Surgical treatment of internal derangement of the temporomandibular joint: long-term evaluation of three techniques

PURPOSE

The long-term outcomes of three different surgical treatments for internal derangement of the temporomandibular joint (TMJ), ie, discoplasty, discectomy without replacement, and discectomy with replacement of the disc with a Proplast-Teflon (Vitek Inc, Houston, TX) interpositional implant (PTIPI) are compared.

MATERIALS AND METHODS

Forty-two cases of internal derangement of the TMJ were treated with disc repair and eminectomy (group A, n = 13), simple discectomy (group B, n = 17) and discectomy combined with insertion of a PTIPI (group C, n = 12). Preoperative and postoperative findings (more than 5-year follow-up) relating to pain, mouth opening, joint noise, and radiographic changes were compared.

RESULTS

Decrease of symptoms after surgery was reported by 77%, 94%, and 83% of the patients (groups A, B, and C, respectively). The decrease in pain intensity ranged from 52% to 71%. Mouth opening increased in 50% to 60% of the patients. The percentage increase ranged from 15% to 26% in the respective groups. Development of osteoarthrosis after surgery was demonstrated in 93% and 100% of the cases in the discectomy and discectomy/disc implant group, respectively, but only in 62% of the discoplasty group.

CONCLUSION

This study demonstrates the importance of a functioning disc in the TMJ. There was no significant difference between the groups concerning symptoms before and after surgery. The discoplasty group, however, showed a high frequency of relapse, which necessitated secondary discectomy. PTIPIs clearly accelerated the development of osteoarthrosis, which may be classified as iatrogenic damage. The need for further research to establish the long-term performance of autogenous grafts and the development of improved alloplastic disc replacement materials is discussed.

Autologous TMJ disk replacement

Several techniques have been advocated for replacement of displaced or diseased temporomandibular joint disks. Techniques are reviewed and the author's experience in managing this complex problem is presented.

In vivo deterioration of proplast-teflon temporomandibular joint interpositional implants: a scanning electron microscopic and energy-dispersive X-ray analysis

The surgical treatment of internal derangements of the temporomandibular joint (TMJ) often involves disc removal. Alloplastic interpositional implants for disc replacement have been widely used to avoid the development of osteoarthritic changes in the TMJ. This study reports the in vivo wear characteristics of Proplast-Teflon (Vitek Inc, Houston, TX) interpositional implants (PTIPI) in 12 patients who had their implants for 13 to 71 (mean 54.6 +/- 5.8 SEM) months. In all cases, changes in the condyle and fossa were found resulting from resorption and replacement of the articulating bone by granulomatous tissue. All implants showed significant signs of wear, such as thinning, cracks, and tears, and overt perforations were seen in five cases. Scanning electron microscopy (SEM) combined with energy-dispersive x-ray microanalysis (EDAX) showed numerous microfragments of the PTIPI in the peri-implant soft tissues. Microfragments were demonstrated by their aluminum content. In addition to the inflammatory foreign-body reaction, it is suggested that there also were toxic and hypersensitivity reactions to aluminum involved in the pathogenesis of the bone destruction.

Treatment outcomes for temporomandibular joint reconstruction after Proplast-Teflon implant failure

A retrospective study of 107 patients (male, n = 13; female, n = 94) with 163 joints previously treated with Proplast-Teflon (PT; Vitek, Inc, Houston, TX) implants was performed. The average time in situ for the PT was 59.8 months (range, 2 to 126 months). Average length of follow-up was 84.6 months (range, 59 to 126 months). Only 12% of joints showed no significant osseous changes radiographically. Forty-five patients (42%) continue to have in situ PT implants and 36% of them experience pain that requires medication; 25% have developed an anterior open bite and malocclusion; 9% have limited vertical opening; and 40% are asymptomatic. Temporomandibular joint (TMJ) reconstruction after PT implant failure was performed with five different autologous tissues or a total joint prosthesis. Autologous tissues used to reconstruct the TMJ and the rates of success were as follows: 1) 31% free temporalis fascia and muscle graft with and 13% without sagittal split ramus osteotomy, 2) 8% dermis, 3) 25% conchal cartilage, 4) 12% costochondral grafts, and 5) 21% sternoclavicular grafts. The success rate decreased in all autologous tissue groups as the number of TMJ surgeries performed before reconstruction increased. Ankylosis was the most common cause of failure. Results of TMJ reconstruction with a total joint prosthesis were as follows: 1) 88% functional and occlusal stability of total joint prosthesis; 2) level of pain reduction was rated as 46% good, 38% fair, and 16% poor; and 3) an average interincisal opening of 27 mm at 24 months or less, and 33 mm at 25 months and beyond.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporalis muscle as a disc replacement in the temporomandibular joint of sheep

Temporalis muscle flaps were evaluated in sheep. Flaps placed following discectomy were examined at 2, 4, 12, and 24 weeks. Histologic evaluation showed avascular necrosis and subsequent displacement and loss of tissue from the joint resulting in close contact between the condyle and fossa. Muscle flaps placed lateral to the joint in operative controls were examined at 4, 12, and 24 weeks. This muscle remained viable while undergoing fibrous replacement. Although the surface layers of the condyle and fossa were initially lost, the tissues were reformed with time. This experiment showed that in the sheep, temporalis muscle does not withstand functional loading within the joint. However, despite the lack of interpositional material, the condyle and fossa can remodel.