The Posterior Segment of the Temporomandibular Joint Capsule and Its Anatomic Relationship

Ethoxysclerol injection into the posterior ligament under single puncture arthroscopy for the treatment of recurrent temporomandibular joint dislocation: a novel technique

The pathogenesis of recurrent chronic dislocation of the temporomandibular joint has been attributed to multiple factors, such as hyperlaxity of the soft tissues or alterations in the size of the temporal eminence. When there are no bone alterations, the injection of sclerosing solutions is an effective treatment that can be performed using a blind technique or with arthroscopy. This study presents an innovative technique for injecting ethoxysclerol into the posterior ligament through single puncture arthroscopy. This approach offers a safe and effective alternative for surgeons without experience in high-complexity arthroscopy who want to ensure precise injection of the agent into the desired anatomical areas.

Otological symptoms in patients with rheumatoid arthritis of the temporomandibular joint

OBJECTIVE

The aim of the current study was to describe the pattern of otological symptoms in patients with rheumatoid arthritis (RA), having clinical temporomandibular joint (TMJ) involvement. This issue had not been previously addressed.

METHODS

A questionnaire and examination findings protocol was applied for 141 patients with RA and 141 control subjects.

RESULTS

Otological symptoms (otalgia, hearing loss, tinnitus, and vertigo), all had a significantly higher incidence in RA patients, compared to control subjects (P = .001).

CONCLUSION

The onset and maintenance of otological symptoms in patients with TMJ involvement by RA probably result from peripheral, as well as central nervous system alterations in sensory stimuli programming.

Temporomandibular disorder: A previously unreported complication of chronic suppurative otitis media

OBJECTIVE

The aim of the current clinical study was to test the hypothesis that chronic suppurative otitis media (CSOM) might be significantly associated with signs of temporomandibular joint (TMJ) internal derangement.

METHODS

The study involved 79 patients with CSOM and 79 control subjects. The TMJ was clinically examined in both groups.

RESULTS

Signs of internal derangement of the TMJ(s) were found in 67.1% of CSOM patients versus 26.6% of control subjects (p = .001).

CONCLUSION

CSOM may be associated with the extension of the inflammatory process into the TMJ, thereby predisposing to internal derangement of the joint.

Hypothesis for the lack of a muscular antagonist to the lateral pterygoid

BACKGROUND

During physiological function of the temporomandibular joint, we have to rely only on elastic structures (in particular the bilaminar zone) for repositioning of the articular disc. A real muscle, however, would be functionally more reasonable. In patients, a decrease of this elasticity is possibly one of the reasons for temporomandibular joint malfunctions, which affect between 16% and 36% of the population.

METHOD

This study assesses the morphogenesis of the murine (Mus musculus) temporomandibular joint with particular regard to the masticatory muscles, to throw light on this topic. To that end, a collection of 11 murine heads ranging from prenatal stages E13.25 to E20 was used and early postnatal stages P0 to P4, which were prepared as histological sections (thickness 8-10 µm) and stained conventionally in order to examine them with light microscopy. Next, the temporomandibular joint and selected surrounding structures, along with the masticatory muscles, were threedimensionally reconstructed using analySIS® software. Subsequently, specific morphometric analyses were performed.

RESULTS AND CONCLUSIONS

The evaluation of the results led to the following conclusions.

Evaluation of Auditory Changes in Patients Undergoing Temporomandibular Joint Discectomy

PURPOSE

Discectomy is 1 of the preferred TMJ surgical procedure for the treatment of internal derangements when conservative and minimally invasive treatments have failed. The purpose of the current study is to investigate whether a TMJ discectomy operation influences auditory function and clinical variables.

MATERIALS AND METHODS

This prospective study was composed of patients who underwent a TMJ discectomy operation between 2016 and 2020. Auditory function was evaluated with pure tone audiometry, tympanometry, and acoustic reflex tests at preoperatively (T₀), postoperative first week (T₁), first month (T₂), and third month (T₃). Clinical parameters including maximum mouth opening (MMO) and TMJ pain were also evaluated at T₀, T₁, T₂, T₃, and sixth month (T₄).

RESULTS

The study consisted of 17 patients (5 males, 12 females) with a mean age of 42.65. A significant reduction in VAS pain scores and MMO values compared to baseline values was achieved in all follow up periods (P^T0-T1= .001; P^T0-T2/T3/T4 < .001). In pure tone audiometry, a significant increase in T₁-T₀ comparisons at 1000 Hz, 2000 Hz, 6000 Hz, 8000 Hz frequencies, and pure tone average (P = .008; P = .005; P = .012; P = .002; P = .001) was observed. In T₃-T₀ comparisons, a statistically significant decrease was observed in pure tone thresholds at 125 Hz and 8000 Hz frequencies (P = .008; P = .01). There was no statistically significant difference in middle ear pressure and compliance values at T₁, T₂, and T₃ compared to T₀ (P ˃ .05). Type C tympanogram was seen in 3 patients at T₁ and in 1 patient at T₂. Acoustic reflex tests were positive in all patients.

CONCLUSIONS

Although mild changes occurred in auditory tests in the early postoperative period, TMJ discectomy procedure has no permanent effect on auditory function.

Approaches to improve integration and regeneration of an ex vivo derived temporomandibular joint disc scaffold with variable matrix composition

Due to their natural biochemical and biomechanical characteristics, using ex vivo tissues as platforms for guided tissue regeneration has become widely accepted, however subsequent attachment and integration of these constructs in vivo is often overlooked. A decellularized porcine temporomandibular joint (TMJ) disc has shown promise as a scaffold to guide disc regeneration and preliminary work has shown the efficacy of surfactant (SDS) treatment within the fibrocartilaginous disc to remove cellular components. The majority of studies focus on the intermediate region of the disc (or disc proper). Using this approach, inherent attachment tissues can be maintained to improve construct stability and integration within the joint. Unlike human disc attachment tissue, the porcine attachment tissues have high lipid content which would require a different processing approach to remove immunogenic components. In order to examine the effect of delipidation on the attachment tissue properties, SDS and two organic solvent mixtures (acetone/ethanol and chloroform/methanol) were compared. Lipid and cellular solubilization, ECM alteration, and seeded human mesenchymal stem cell (MSC) morphology and viability were assessed. Quantitative analysis showed SDS treatments did not effectively delipidate the attachment tissues and cytotoxicity was noted toward MSC in these regions. Acetone/ethanol removed cellular material but not all lipids, while chloroform/methanol removed all visible lipid deposits but residual porcine cells were observed in histological sections. When a combination of approaches was used, no residual lipid or cytotoxicity was noted. Preparing a whole TMJ graft with a combined approach has the potential to improve disc integration within the native joint environment.

Prestyloid compartment of the parapharyngeal space: a histological study using late-stage human fetuses

PURPOSE

Although the prestyloid space is well known, its definition still remains unclear.

METHODS

Using semiserial sagittal sections of 15 late-stage human fetal heads, we studied details of the topographical anatomy.

RESULTS

A definite posterior marginal fascia of the space was seen along the anterior aspect of the stylopharyngeus and styloglossus muscles. Inferiorly, the prestyloid space faced the bucallis and medial pterygoid muscles and the submandibular gland. The external carotid artery ran along the posterolateral side of the space. The tensor veli palatini fascia did not contribute to the posterior marginal fascia. A major supplying artery of the space was the ascending palatine artery.

CONCLUSIONS

The prestyloid compartment of the parapharyngeal space (hereafter, the prestyloid space) seems to correspond to a border between the first and second pharyngeal arch derivatives. This concept may provide a better understanding of prestyloid space.

Histological study of the extratympanic portion of the discomallear ligament in adult humans: a functional hypothesis

This study was carried out on histological aspects of the extratympanic portion of the discomallear ligament (DL) in adult humans. The temporomandibular joint (TMJ) was dissected bilaterally in 20 cadavers; in 15 cases the articular disc (AD) and the retroarticular tissue were extirpated. The extratympanic portion of the DL had the shape of a base-down triangle, in relation to the AD, and an upper vertex, in relation to the petrotympanic fissure. In five cases, the base, measured bilaterally, had an average length of 6.4 mm, while the distance from the base to the upper vertex averaged 9.3 mm in length. The extratypanic portion of the DL is an intrinsic ligament of the TMJ, composed of collagen fibres and abundant elastic fibres. We propose that this ligament could act as a tensor of the synovial membrane in movements of the TMJ.

Immunolocalization and expression of lubricin in the bilaminar zone of the human temporomandibular joint disc

Lubricin, which is a boundary joint lubricant, was investigated immunohistochemically in the bilaminar zone (BZ) of the human temporomandibular joint (TMJ), without any degenerative changes. Immunohistochemistry for lubricin detection was carried out on 33 TMJ discs obtained from 17 cadavers. Sections were incubated with diluted rabbit polyclonal anti-lubricin antibody and scored according to the percentage of lubricin immunopositive cells. Three different TMJ disc tissue compartments were analyzed, namely: the upper lamina, the inferior lamina and the loose connective tissue in the space between the laminae. The Mann-Whitney U test was used to compare protein expression (lubricin) among disc specimens' regions. Staining was noted within the TMJ disc cell populations in every disc tissue sample, with almost every cell immunolabeled by the lubricin antibody. The number of disc cells immunolabeled was almost the same in the 3 bilaminar zone regions. Positive extracellular matrix staining was also seen. The results of the present study suggest that lubricin is expressed in the TMJ disc bilaminar zone. Lubricin may have a role in normal disc posterior attachment physiology through the prevention of cellular adhesion as well as providing lubrication during normal bilaminar zone function.