A Quantitative Evaluation of Inflammatory Cells in Human Temporomandibular Joint Tissues From Patients With and Without Implants

Decellularized small intestine submucosa device for temporomandibular joint meniscus repair: Acute timepoint safety study

Temporomandibular joint (TMJ) Meniscus removal is an option for the patient to regain full range of motion if the disc is irreversibly damaged or unable to be reduced. However, this procedure leaves the joint vulnerable to condylar remodeling and degeneration. We have shown that extracellular matrix (ECM) scaffolds remodel into a tissue with near native TMJ meniscus in previous studies. The next step towards clinical translation is to manufacture the ECM scaffold as a device under good manufacturing practices (GMP) and test it in a pre-clinical animal study under good laboratory practices (GLP). The primary objective of this study was to evaluate the in-vivo histopathological response to a Prototype GMP manufactured device made of decellularized porcine small intestinal submucosa (SIS), by observing for signs of surrounding tissue reaction to the device that are indicative of an adverse host response in comparison to an empty control at 21 days post-surgical implantation in a canine TMJ meniscus removal and implant model in a GLP setting. The conclusive findings were that the ECM device is safe for placement in the TMJ. After 21 days post implantation, histology of tissue surrounding the device and draining lymph nodes showed that the Prototype GMP device had no negative effects compared to the empty site (as evaluated by the board-certified veterinary pathologist). Furthermore, there was a lack of negative findings for clinical pathology (hematology and clinical chemistry), mortality, and body weight/weight change. Future studies will go to one year after implantation to show that the remodel device remains as a viable tissue with near native mechanical properties.

Surface wear in a custom manufactured temporomandibular joint prosthesis

The wear of a novel temporomandibular joint (TMJ) prosthesis was evaluated in an animal model. The prosthesis consisted of an additively manufactured titanium alloy (Ti₆Al₄V) mandibular condyle and glenoid fossa created through selective laser melting, with a machined vitamin E‐enriched ultra‐high molecular weight polyethylene (UHMWPE) surface attached to the fossa. Thirteen TMJ prosthesis were implanted in sheep, six of which had condylar heads coated with HadSat® diamond‐like carbon (H‐DLC). Euthanasia took place after 288 days, equaling 22 years of human mastication. Linear and volumetric wear analysis of the fossa was performed by optical scanning. The condylar head surfaces were assessed by scanning electron and confocal laser microscopy. The average linear UHMWPE wear, when combined with the coated condyle, was 0.67 ± 0.28 mm (range: 0.34–1.15 mm), not significantly differing (p = .3765, t‐test) from the non‐coated combination average (0.88 ± 0.41 mm; range: 0.28–1.48 mm). The respective mean volumetric wear volumes were 25.29 ± 11.43 mm³ and 45.85 ± 22.01 mm³, not significantly differing (p = .1448, t‐test). Analysis of the coated condylar surface produced a mean Ra of 0.12 ± 0.04 μm and Sa of 0.69 ± 0.07 μm. The non‐coated condylar surface measured a mean Ra of 0.28 ± 0.17 μm and Sa of 2.40 ± 2.08 μm. Both Sa (p = .0083, Mann–Whitney U test) and Ra (p = .0182, Mann–Whitney U test), differed significantly. The prosthesis exhibits acceptable wear resistance and addition of the H‐DLC‐coating significantly improved long‐term condylar surface smoothness.

A randomized controlled preclinical trial on 3 interposal temporomandibular joint disc implants: TEMPOJIMS-Phase 2

The effort to develop an effective and safe temporomandibular joint (TMJ) disc substitute has been one of the mainstreams of tissue engineering. Biodegradable customized scaffolds could approach safety and effectiveness to regenerate a new autologous disc, rather than using non-biodegradable materials. However, it is still technically challenging to mimic the biomechanical properties of the native disc with biodegradable polymers. In this study, new 3D tailored TMJ disc implants were developed: (1) Poly(glycerol sebacate) (PGS) scaffold reinforced with electrospun Poly(εcaprolactone) (PCL) fibers on the outer surface (PGS+PCL); (2) PCL and polyethylene glycol diacrylate (PEGDA) (PCL+PEGDA); and (3) PCL. The TMJ implants were tested in a randomized preclinical trial, conducted in 24 black Merino sheep TMJ, perfoming bilateral interventions. Histologic, imaging, and kinematics analysis was performed. No statistical changes were observed between the PGS+PCL disc and the control group. The PCL+PEGDA and PCL groups were associated with statistical changes in histology (p = 0.004 for articular cartilage mid-layer; p = 0.019 for structure changes and p = 0.017 for cell shape changes), imaging (p = 0.027 for global appreciation) and dangerous material fragmentation was observed. No biomaterial particles were observed in the multi-organ analysis in the different groups. The sheep confirmed to be a relevant animal model for TMJ disc surgery and regenerative approaches. The PCL and PCL+PEGDA discs presented a higher risk to increase degenerative changes, due to material fragmentation. None of the tested discs regenerate a new autologous disc, however, PGS+PCL was safe, demonstrated rapid resorption, and was capable to prevent condyle degenerative changes.

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.

Medialisation thyroplasty with tensor fascia lata: a novel approach for reducing post-thyroplasty complications

BACKGROUND

Medialisation thyroplasty is considered the 'gold standard' treatment for unilateral vocal fold paralysis, enabling improvement of voice and swallowing function, and preventing life-threatening aspiration events. The most commonly used laryngeal implants induce some degree of local tissue inflammatory response, and carry the risk of immediate or delayed implant extrusion.

METHODS

This paper describes a novel approach for medialisation thyroplasty. Specifically, it utilises a ribbon of autologous tensor fascia lata harvested at the time of surgery. This is layered within the paraglottic space in a manner similar to Gore-Tex thyroplasty.

RESULTS

Thus far, this method has been accomplished in two patients with unilateral vocal fold paralysis, who also received prior radiotherapy to the head and neck.

CONCLUSION

Given the increased risk of post-operative wound breakdown and infection in irradiated patients, it is suggested that this new approach will lead to improved outcomes, and a decrease in complications such as extrusion or wound infection, particularly in this patient population.

Extracellular matrix bioscaffolds in tissue remodeling and morphogenesis

During normal morphogenesis the extracellular matrix (ECM) influences cell motility, proliferation, apoptosis, and differentiation. Tissue engineers have attempted to harness the cell signaling potential of ECM to promote the functional reconstruction, if not regeneration, of injured or missing adult tissues that otherwise heal by the formation of scar tissue. ECM bioscaffolds, derived from decellularized tissues, have been used to promote the formation of site appropriate, functional tissues in many clinical applications including skeletal muscle, fibrocartilage, lower urinary tract, and esophageal reconstruction, among others. These scaffolds function by the release or exposure of growth factors and cryptic peptides, modulation of the immune response, and recruitment of progenitor cells. Herein, we describe this process of ECM induced constructive remodeling and examine similarities to normal tissue morphogenesis.

Methotrexate pharmacotherapy for implant-related temporomandibular joint pain: a case report

This article presents a patient experiencing several years of pain associated with bilateral failed temporomandibular joint (TMJ) Proplast/Teflon fossa prostheses. Despite surgical removal of the prostheses and comprehensive conservative management, including typical pharmacotherapy approaches for chronic pain, pain was still not relieved, and management was revised to target a putative chronic inflammatory disorder. Methotrexate was prescribed because of its known efficacy for inflammation and pain reduction in rheumatoid arthritis. Titration of methotrexate dosage over 5 months to a weekly dose of 20 mg resulted in reduced pain intensity at rest, increased pain-free maximal jaw opening, and a reduction in the sensory component of the McGill Pain Questionnaire. Maximum assisted jaw opening remained the same, as did the palpation tenderness of both TMJs and of the masseter and temporalis muscles. Methotrexate pharmacotherapy may represent a viable option when conservative treatments have failed to provide significant pain relief in patients who have had Proplast/Teflon TMJ implants.

Extracellular matrix as an inductive scaffold for functional tissue reconstruction

The extracellular matrix (ECM) is a meshwork of both structural and functional proteins assembled in unique tissue-specific architectures. The ECM both provides the mechanical framework for each tissue and organ and is a substrate for cell signaling. The ECM is highly dynamic, and cells both receive signals from the ECM and contribute to its content and organization. This process of "dynamic reciprocity" is key to tissue development and for homeostasis. Based upon these important functions, ECM-based materials have been used in a wide variety of tissue engineering and regenerative medicine approaches to tissue reconstruction. It has been demonstrated that ECM-based materials, when appropriately prepared, can act as inductive templates for constructive remodeling. Specifically, such materials act as templates for the induction of de novo functional, site-appropriate, tissue formation. Herein, the diverse structural and functional roles of the ECM are reviewed to provide a rationale for the use of ECM scaffolds in regenerative medicine. Translational examples of ECM scaffolds in regenerative are provided, and the potential mechanisms by which ECM scaffolds elicit constructive remodeling are discussed. A better understanding of the ability of ECM scaffold materials to define the microenvironment of the injury site will lead to improved clinical outcomes associated with their use.

Inductive, scaffold-based, regenerative medicine approach to reconstruction of the temporomandibular joint disk

PURPOSE

A device composed of extracellular matrix (ECM) was investigated as an inductive template in vivo for reconstruction of the temporomandibular joint (TMJ) disk after discectomy.

MATERIALS AND METHODS

A scaffold material composed of porcine-derived ECM was configured to mimic the shape and size of the TMJ. This device was implanted in a canine model of bilateral TMJ discectomy. After discectomy, 1 side was repaired with an ECM scaffold material and the contralateral side was left empty as a control. At 6 months after implantation, the joint space was opened, the joints were evaluated for signs of gross pathologic degenerative changes, and newly formed tissue was excised for histologic, biochemical, and biomechanical analysis.

RESULTS

The results showed that implantation of an initially acellular material supported the formation of site-appropriate, functional host tissue that resembled that of the native TMJ disk. Furthermore, this prevented gross degenerative changes in the temporal fossa and mandibular condyle. No tissue formation and mild to severe gross pathologic changes were observed in the contralateral controls.

CONCLUSIONS

These results suggest that an ECM-based bioscaffold could represent an off-the-shelf solution for TMJ disk replacement.