Gelatin methacryloyl hydrogel with and without dental pulp stem cells for TMJ regeneration: An in vivo study in rabbits.

BACKGROUND: In the last decade, tissue-engineering strategies for regenerating the temporomandibular joint (TMJ) have been investigated. This may be a promising strategy for the minimally invasive restoration of joint integrity. OBJECTIVES: To evaluate whether dental pulp stem cells (DPSCs) loaded in a light-occured hydrogel made of gelatin methacryloyl (GelMA) enhance the regeneration of osteochondral defects in the rabbit TMJ. MATERIALS AND METHODS: Defects were filled with GelMA alone (control group; n = 4) or filled with GelMA loaded with rabbit DPSCs (experimental group; n = 4), In one group, the TMJ capsule was opened without creating a defect (sham group; n = 2). The following micro-CT parameters were analysed: bone volume to total volume ratio (BV/TV%) and bone mineral density (BMD). Histological evaluation was performed to assess cartilage regeneration features. A semi-quantitative scoring system was also used to evaluate the defects. RESULTS: All groups had no statistical difference regarding the micro-CT parameters. The highest mean healing score was found for the experimental group. After 4 weeks, there were no signs of hydrogel in either group or no signs of inflammation in the adjacent tissues. The tissue formed in the defect was dense fibrous connective tissue. CONCLUSION: Adding DPSCs to GelMA did not provide a regenerative enhancement in TMJ osteochondral defects. This resulted in similar micro-CT parameters after 4 weeks of healing, with improved signs of subchondral bone regeneration but no cartilage regeneration.

Arthroscopic management of synovial chondromatosis with skull base perforation: A case report and literature review.

OBJECTIVE: Synovial chondromatosis (SC) of the temporomandibular joint (TMJ) is a synovial membrane disease characterized by the formation of cartilaginous nodules (CN), that may erode the skull base. Historically, cases with skull base involvement have been treated with open surgery. We report a case of TMJ SC with skull base perforation treated and repaired via minimally invasive TMJ arthroscopy and describe the advanced endoscopic operative maneuvers performed. CASE REPORT: A 34-year-old male presented with a 4-year history of malocclusion and right TMJ arthralgia. Clinical examination demonstrated malocclusion and direct pressure loading pain. Advanced imaging revealed glenoid fossa erosion and numerous homogenous hypointense lesions within an effusion. The initial surgical plan included diagnostic TMJ arthroscopy followed by conversion to open arthroplasty. Endoscopic operative maneuvers allowed for the accomplishment of the surgical goals, completely arthroscopically. Histopathology confirmed SC, and the patient remains on observation, with relief of symptoms. CONCLUSION: Advanced arthroscopy is a viable treatment option for select cases of TMJ SC with skull base involvement that allowed for access to the joint space, retrieval of biopsy specimens and CN, and repair of the skull defect.

A rabbit model to investigate temporomandibular joint osteochondral regeneration.

OBJECTIVE: The objective of this study was 2-fold: (1) to describe the rabbit temporomandibular joint (TMJ) anatomy and (2) to provide a detailed, step-by-step description of a minimally invasive approach to perform a standard osteochondral TMJ defect that can be used to investigate the regenerative potential of biomaterials. STUDY DESIGN: This study was performed in 2 steps. In the first, a total of 8 rabbit carcasses (n = 16 joints) were used to study the normal TMJ anatomy and histology to develop a minimally invasive approach to access the articulating surface of the condyle to perform a standard osteochondral defect. In the second, the surgical procedure was performed in 10 live animals to evaluate the feasibility of the model and to evaluate the regenerative potential of a biodegradable light-cured hydrogel seeded with stem cells (results not shown). RESULTS: The cartilage of the mandibular condyle showed 4 layers: fibrous, proliferative, hypertrophic, and a zone of calcified cartilage. Positive safranin O staining was observed in the cartilage. The mean duration of the procedure (from incision to last stitch) was 35.5 (±9.21) minutes. All animals survived the procedures without any major complications. CONCLUSIONS: This animal model represents an easy and nonmorbid surgical approach to rabbit TMJ.

The Inequitable Global Burden of Lip and Oral Cancers: Widening Disparities Across Countries.

PURPOSE: In light of continued innovation in cancer immunotherapy regimens and surgical management, no studies currently exist assessing the effect of these advances on global disparities in lip and oral cavity cancer disease burden. The purpose of this study is to characterize longitudinal trends in disease burden caused by lip and oral cavity cancers globally. MATERIALS AND METHODS: This retrospective, longitudinal cohort study extracted data on lip and oral cavity cancer disease burden from The Global Health Data Exchange for 1990-2017. The primary predictor variable was country human development index (HDI). The primary outcome variable was disease burden, measured by age-standardized disability-adjusted life years (DALYs) per 100,000 population, listed for each individual country. Additional variables assessed include country-level data on alcohol consumption and tobacco smoking. Concentration indices were also calculated. Mann-Whitney U and Kruskal-Wallis one-way analysis of variance tests with Bonferroni correction were utilized with a significance threshold of 0.008. RESULTS: A total of 185 countries met inclusion criteria. Global age-standardized DALYs increased from 44.5 ± 35.7 to 51.1 ± 41.1 from 1990 to 2017. High HDI and medium HDI countries showed a +37.6% and +22.4% median increase in DALYs, respectively, which is significantly greater than very-high HDI (+3.8%) and low HDI countries (-0.5%) (P < .001). The concentration index for lip and oral cavity cancer became increasingly negative from -0.064 to -0.077 from 1990 to 2015. In 2017, disease burden was concentrated in South Asia and Eastern Europe. CONCLUSIONS: High and medium HDI countries experienced a disproportionate growth in lip and oral cavity cancer disease burden. These findings may have resulted from increased life expectancy among these countries. Global and public health policy initiatives should focus on understanding the mechanisms driving these disparities with the goal of reducing disease burden globally.

Assessment of Intraoperative Time for Head and Neck Cancer Surgeries Compared With Medicare Work Time.

PURPOSE: Surgeon reimbursement is dictated in part by the operative time necessary to complete a procedure. The purpose of this study is to compare insurer-set time to true intraoperative time for common head and neck cancer procedures. METHODS: This retrospective cohort study compares intraoperative times between the 2019 Center for Medicare and Medicaid Services (CMS) work-time estimates and the 2017 to 2018 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) data sets for 10 commonly billed head and neck cancer procedures. The primary predictor variable was common head and neck oncologic and reconstructive procedures with corresponding Current Procedural Terminology (CPT) code. The primary outcome variable includes the computed difference between CMS and NSQIP times. Additional variables collected include patient demographics (gender, age, race, and inpatient/outpatient) and work relative value unit (wRVU) per CPT code. Analysis of variance was used to evaluate differences in intraoperative times across CPT codes. Linear regression using standardized coefficients were calculated between CMS time and NSQIP time; CMS time and wRVUs; and NSQIP time and wRVUs. RESULTS: There were 8,330 subjects (44% female, 57.7% inpatient) across 10 CPT codes. Analysis of variance revealed intercode variability in median intraoperative times between CMS and NSQIP (P < .001). CMS underestimated the time necessary to complete excision of malignant tumor mandible (CPT 21045) by 315 minutes. CMS overestimated the time necessary for excision of tongue lesion (CPT 41112) by 5 minutes. Overall, CMS intraoperative time estimates were neither invariably longer nor consistently shorter than NSQIP procedural times (ß, 0.85; 95% confidence interval, 0.43 to 1.26). CONCLUSIONS: CMS estimates of time needed to complete head and neck cancer surgeries varies from national intraoperative times. No consistent trend in underestimation or overestimation of procedure time was found. Improving the accuracy of CMS time estimates used in determining surgeon reimbursement for head and neck cancer procedures may be warranted.

Induction, Treatment, and Prevention of Temporomandibular Joint Ankylosis-A Systematic Review of Comparative Animal Studies.

PURPOSE: Several animal models of temporomandibular joint ankylosis (TMJA) have been described for more than the past 2 decades. The aim of this study was 2-fold: 1) to compile and summarize the evidence of animal studies that compare different forms to induce, treat (disease already established), or prevent (after trauma) TMJA; and 2) to address the following focused question: what is the quality of reporting in these studies? MATERIALS AND METHODS: A systematic review was conducted. Animal studies conducted up to October 2019 comparing at least 2 procedures to induce, treat (disease already established), or prevent (after trauma) TMJA were considered. Compliance with the Animal Research Reporting In Vivo Experiments guidelines was checked for all studies. Studies evaluating treatment of TMJA or preventive measures also were evaluated using the SYstematic Review Center for Laboratory animal Experimentation's risk of bias tool for animal studies. RESULTS: A total of 24 studies were included. The studies were evaluated for feasibility regarding data synthesis, and a meta-analysis was not suitable because of methodological differences, mainly regarding the animal model chosen and surgical procedures performed to induce TMJA. In 17 articles, authors aimed to investigate different procedures to induce TMJA (fibrous, fibro-osseous, or bony). In 7 articles, different treatment or preventive strategies were compared. The sheep was the most used animal in models of TMJA. Only 25% (6 of 24) of studies reported some step to minimize bias (ie, blinding of investigators, randomization procedures, or allocation concealment). Approximately 54% (13 of 24) of articles clearly commented on study limitations and potential sources of bias. Further animal studies on TMJA should consider improving their reporting standards to increase their validity and improve the reproducibility of animal experiments.

Correlation of Arthroscopic and Histologic Findings in Synovial Membrane Disease of the Temporomandibular Joint.

PURPOSE: The purpose of the present study was to correlate specific arthroscopic findings in temporomandibular joint (TMJ) arthroscopy and histologic results from arthroscopic-guided synovial biopsy. PATIENTS AND METHODS: A retrospective cohort study was completed of patients who had undergone arthroscopy and arthroscopic synovial biopsy from January 1, 2011 to March 31, 2016 at the senior author's practice in Miami, Florida. The demographic, arthroscopic, histologic, serologic, and historical variables were recorded by electronic medical record review. Two-tailed Fisher's exact tests were used to test the correlation of the arthroscopic and histologic variables. RESULTS: A total of 210 patients were included in the present study. The mean age was 43.1 ± 18.8 years, and the study population included 91.7% women. The following histologic findings had significant associations: lymphoplasmacytic infiltrate with petechiae synovitis (P = .0018), chronic inflammation with joint stenosis (P = .019), and crystal deposition with visualization of crystals (P = .0472). Hyperplastic synovium found on histologic examination was associated with both petechiae synovitis and adhesions. Histologic vascular proliferation was associated with synovial plica and joint stenosis. CONCLUSIONS: The findings from the present study indicated an association between specific findings during arthroscopy and histologic findings. A prospective study is required to validate the findings to evaluate their utility in patient care.

Early Clinical Outcomes of Arthroscopic Management of the Failing Alloplastic Temporomandibular Joint Prosthesis.

PURPOSE: Total joint replacement is the recommended treatment for end-stage temporomandibular joint (TMJ) disease. The goal of treatment is to help the return to acceptable function with improvement of the maximum incisal opening (MIO) and a reduction of pain. When a prosthetic joint shows late complications, surgical management includes an open approach, with debridement, cultures, and prosthetic replacement as options. The purpose of the present study was to evaluate the early outcomes of arthroscopic management of failing prosthetic TMJs (PTMJs). PATIENTS AND METHODS: The inclusion criteria were patients with custom or stock joints with complaints of limitation of mouth opening and pain, who had undergone arthroscopy. The exclusion criteria were patients with radiographic heterotopic bone formation, improvement with antibiotic treatment, and failed hardware found on imaging studies. RESULTS: A total of 9 patients were included in the present study (all women), with 5 unilateral and 4 bilateral PTMJs, for a total of 13 sides that underwent arthroscopy. Their mean age was 40 years (range, 23 to 65 years). The mean preoperative MIO was 25 mm, and the mean preoperative visual analog scale for pain and functional limitation scores were both 8 of 10. The corresponding scores were 4 of 10 and 3 of 10 at 3 months postoperatively. CONCLUSIONS: Arthroscopic management of prosthetic joints has been reported in orthopedic studies, with benefits shown in the diagnosis and management of synovial impingement and arthrofibrosis. The results from the present study demonstrated that the early clinical outcomes of arthroscopic management of PTMJs is promising for decreasing pain and increasing the MIO. Larger studies with longer follow-up are needed to further classify the different causes of prosthetic failure and advance the approaches to management.

Is Temporomandibular Joint Arthroscopy Effective in Managing Pediatric Temporomandibular Joint Disorders in the Short- and Long-Term?

PURPOSE: Although temporomandibular joint (TMJ) arthroscopy outcomes have been well documented in the adult population, conclusive data are lacking for pediatric patients with TMJ disorders. The aim of the present study was to evaluate the early and late outcomes of TMJ arthroscopy in the pediatric population. PATIENTS AND METHODS: We performed a retrospective analysis to evaluate the short- (1-month) and long-term (1-year) improvements in the visual analog scale (VAS) scores for pain after pediatric TMJ arthroscopy from 2008 to 2016. The arthroscopic interventions varied according to the diagnostic findings and Wilkes classification. The primary outcome variable was the magnitude of VAS score for pain (0, no pain; 100, worst pain) at 1 year postoperatively. The secondary outcome variables were the short-term for the VAS score for pain and the short- and long-term outcomes for perceived jaw dysfunction (0, normal jaw function; 100, complete jaw dysfunction), mouth opening, joint loading (contralateral joint pain when biting on the canine), joint noise, and muscle pain. Univariate, bivariate, and multivariate statistical analyses were performed with the significance level set at P < .05. RESULTS: A total of 23 patients (37 joints), with a mean age of 14.1 years (range, 12.8 to 16.7 years) had undergone TMJ arthroscopic surgery with short- and long-term postoperative follow-up data available. The VAS scores for pain showed average improvements of 26% in the short-term (P < .0001) and 25% in the long-term (P < .0008). Perceived jaw dysfunction showed an average improvement of 23.8% in the short-term (P < .0001) and 19.2% in the long-term (P < .0008). The average mouth opening had improved by 5.4 mm in the short-term (P < .0016) and 8.2 mm in the long-term (P < .0001). Controlling for stage and diagnosis, the patients with Wilkes III showed the most benefit with statistically significant improvements in pain, jaw dysfunction, maximum interincisal opening, and joint loading pain. CONCLUSIONS: TMJ arthroscopy could be an effective and minimally invasive form of surgical intervention for treating Wilkes II, III, and IV TMJ disorders in the pediatric population.

Minimally Invasive Endoscopic Oral and Maxillofacial Surgery.

Advances in technology and specialized instrumentation allow surgeons to study, refine, and modify minimally invasive surgery (MIS) to replace standard operations. This has occurred across many surgical specialties. The benefits of MIS include less swelling, less pain, shorter hospital stay, and faster return to daily activities. Oral and maxillofacial endoscopic techniques are used for access to the ramus condyle unit, maxillary sinus, zygoma, orbit, temporomandibular joint, and salivary ductal system. Although endoscopic techniques are also used in facial cosmetic surgery, this discussion focuses on noncosmetic procedures.

Potential Indications for Tissue Engineering in Temporomandibular Joint Surgery.

PURPOSE: Musculoskeletal tissue engineering has advanced to the stage where it has the capability to engineer temporomandibular joint (TMJ) anatomic components. Unfortunately, there is a paucity of literature identifying specific indications for the use of TMJ tissue engineering solutions. The objective of this study was to establish an initial set of indications and contraindications for the use of engineered tissues for replacement of TMJ anatomic components. FINDINGS: There was consensus among the authors that the management of patients requiring TMJ reconstruction as the result of 1) irreparable condylar trauma, 2) developmental or acquired TMJ pathology in skeletally immature patients, 3) hyperplasia, and 4) documented metal hypersensitivities could be indications for bioengineered condyle and ramus TMJ components. There was consensus that Wilkes stage III internal derangement might be an indication for use of a bioengineered TMJ disc or possibly even a disc-like bioengineered "fossa liner." However, there was some controversy as to whether TMJ arthritic disease (e.g., osteoarthritis) and reconstruction after failed alloplastic devices should be indications. Further research is required to determine whether tissue-engineered TMJ components could be a viable option for such cases. Contraindications for the use of bioengineered TMJ components could include patients with TMJ disorders and multiple failed surgeries, parafunctional oral habits, persistent TMJ infection, TMJ rheumatoid arthritis, and ankylosis unless the underlying pathology can be resolved. CONCLUSIONS: Biomedical engineers must appreciate the specific indications that might warrant TMJ bioengineered structures, so that they avoid developing technologies in search of problems that might not exist for patients and clinicians. Instead, they should focus on identifying and understanding the problems that need resolution and then tailor technologies to address those specific situations. The aforementioned indications and contraindications are designed to serve as a guide to the next generation of tissue engineers in their strategic development of technologies to address specific clinical issues.

Arthroscopic discopexy is effective in managing temporomandibular joint internal derangement in patients with Wilkes stage II and III.

PURPOSE: Disc repositioning for temporomandibular joint (TMJ) internal derangement (ID) is a well-established surgical technique with variable success. The purpose of the present study was to assess the outcomes after arthroscopic disc repositioning (discopexy) for TMJ ID. PATIENTS AND METHODS: This was a prospective, cohort, single-institutional clinical study. The study included patients with TMJ ID in whom diagnostic arthroscopy had failed. These patients were presented and treated at Miami Oral and Maxillofacial Surgery, Baptist Hospital (Miami FL). The predictive variable was the Wilkes diagnostic categories, presented in 2 groups: II and III versus IV and V. The primary outcome variable was the absence of joint pain at 12 months postoperatively. The secondary outcome variables included joint function, maximum interincisal opening, medication use, joint loading sign, and muscle pain. The patients were followed for 1 year postoperatively. The statistical analyses included paired and independent sample Student's t test, χ(2) test, and logistic regression analysis. RESULTS: A total of 32 subjects (42 joints), with a mean age of 31 years, were included in the present study; 28 (87.5%) were women. Of the 42 joints, 71.4% were classified as Wilkes stage II and III. A successful outcome was seen in 69% of the studied subjects and in 86.7% of the Wilkes II and III group versus 25% of the Wilkes IV and V group (P = .001). CONCLUSION: The results of the present study have shown that TMJ arthroscopic discopexy is an effective and predictable treatment of patients with TMJ ID in whom primary TMJ arthroscopy failed. Our results have also shown that patients with Wilkes II or III TMD will have the most successful outcome.

Arthroscopic electrothermal capsulorrhaphy for the treatment of recurrent temporomandibular joint dislocation.

Acute temporomandibular joint dislocation is a common occurrence that is generally treated by conservative therapy. In some patients, this can become a chronic recurrent condition. This recurrent temporomandibular joint dislocation (RTD) can significantly decrease the patient's quality of life and require some form of surgical intervention for correction. The purpose of this study is to present a minimally invasive alternative treatment for RTD using operative arthroscopy. 11 patients treated for recurrent temporomandibular dislocation between 2004 and 2010 were retrospectively analyzed. Electrothermal capsulorrhaphy was performed using a standard double puncture operative arthroscopy with a Hol:YAG laser and/or electrocautery. Postoperatively the patients were monitored for 6 months to 6 years. Of the 11 subjects, 2 suffered a recurrence of temporomandibular dislocation and required open arthrotomy for correction. The other 9 patients had no signs of recurrence or any significant postoperative loss of function. Electrothermal capsulorrhaphy is an effective and minimally invasive method for the treatment of RTD.