Anatomical and histological components of the bilaminar zone of the temporomandibular joint: a narrative review / Componentes anatómicos e histológicos de la zona bilaminar de la articulación temporomandibular: una revisión narrativa

SUMMARY: One of the structures which contributes to the correct functioning of the Temporomandibular Joint (TMJ) is the Articular Disc (AD). Viewed in sagittal section, the AD is divided into four zones, the last is the Bilaminar Zone (BZ). The BZ is essential for keeping the AD in its superior position and for retracting the AD to posterior in the maximum aperture position. Its composition and the disposition of its components is unclear. The object of this narrative review is to update concepts on the anatomy of the BZ, with its variations, histological components, vascularization and innervation. The following databases were reviewed: PUBMED, SCOPUS, EMBASE, WEB OF SCIENCE, SciELO and LILACS. Only studies in human beings without alterations to the TMJ, using dissection in cadavers or radiography in live subjects, were included. Systematic reviews, letters to the editor, technical articles and experimental or quasi-experimental studies in animals were excluded. This review included a total of 24 articles which corresponded to the proposed research object. Our results describe the morphology of the BZ, its anatomical relations and possible variations, its histological components, types of fibre and distribution percentages; the latter are discussed in the literature, but no consensus exists. This is not the case for the vascularization and innervation of the BZ; all authors analyzed agree on these points, with just one author adding two possible arteries that may play a part in irrigation. Furthermore, a large number of authors recognize the discomalleolar ligament and its close relation with the BZ.

RESUMEN: Una de las estructuras que contribuye al correcto funcionamiento de la Articulación Temporomandibular (ATM) es el Disco Articular (DA). Visto en sección sagital, el DA se divide en cuatro zonas, la última de las cuales es la Zona Bilaminar (BZ). El BZ es esencial para mantener el AD en su posición superior y para retraer el AD hacia atrás en la posición de máxima apertura. Su composición y disposición de sus componentes no está clara. El objetivo de esta revisión es actualizar conceptos sobre la anatomía del BZ, además de sus variaciones, componentes histológicos, vascularización e inervación. Se revisaron las siguientes bases de datos: PUBMED, SCOPUS, EMBASE, WEB OF SCIENCE, SciELO y LILACS. Se incluyeron estudios en seres humanos sin alteraciones de la ATM, utilizando disección en cadáveres o radiografía en sujetos vivos. Se excluyeron las revisiones sistemáticas, cartas al editor, artículos técnicos y estudios experimentales o cuasi-experimentales en animales. Esta revisión incluyó un total de 24 artículos que correspondían al objeto de investigación propuesto. Nuestros resultados describen la morfología del BZ, sus relaciones anatómicas y posibles variaciones, sus componentes histológicos, tipos de fibras y porcentajes de distribución; estos últimos se discuten en la literatura, pero no existe consenso. Este no es el caso de la vascularización e inervación del BZ; todos los autores analizados coinciden en estos aspectos, y solo un autor agrega dos posibles arterias que pueden tener un papel en la irrigación. Además, un gran número de autores reconocen el ligamento disco maleolar y su estrecha relación con el BZ.

Evaluating the Effect of Dextrose Prolotherapy on Temporomandibular Disorders by Choosing Different Injection Sites- A Comparative Clinical Study

Introduction: Prolotherapy is a minimally invasive techniqueused in the treatment of temporomandibular disorders.Prolotherapy agent induces an inflammatory process in thejoint, stimulates fibroblast proliferation, hence facilitatesthe healing process and strengthens the joint and associatedligaments and tendons. The main aim of this article wasto study the effect of 25% dextrose prolotherapy ontemporomandibular joint pain, clicking and maximum mouthopening by using different injection sites.Material and methods: Sixty patients with establisheddiagnosis of unilateral disc displacement with reduction whocomplained of unilateral symptoms (pain and clicking) wereincluded in the study. They were randomly allocated to threegroups (Group A, Group B and Group C) of 20 patients each.Group A patients received intra-articular injections into thesuperior joint space, Group B patients received injections intothe inferior joint space where as Group C patients were giveninjections into the retrodiscal tissues. Each group receivedsubsequent injections at first, second and third weeks at therespective sites. Pain, clicking and maximum mouth opening(MMO) was recorded pre-operatively, post-operatively at 3weeks and 2 months.Results: Group B and Group C patients showed a significantdecrease in the pain score at 3 weeks and 2 months postoperatively while as no significant pain relief was observed inGroup A. Maximum mouth opening improved significantly inGroup B and Group C patients at 3 weeks and 2 months andwas highest in Group C. Reduction in clicking was best seenin Group C.Conclusion: Prolotherapy is more effective when injectionsite is selected as per the type of symptoms of the patientswith temporomandibular disorders.

Contrast Spreading Patterns in Retrodiscal Transforaminal Epidural Steroid Injection

OBJECTIVE: To observe the contrast spreading patterns in the retrodiscal (RD) approach for transforaminal epidural steroid injections and their effect on pain reduction. METHOD: Patients with L5 radiculopathy who were scheduled to receive lumbar TF-EPB were consecutively included. We randomly divided them into the L4-5 RD and L5-S1 RD groups and administered 1 cc of contrast dye into epidural space. We observed the shape and the location of contrast dye on the anterior-posterior and lateral views. We injected 1 cc of 0.5% lidocaine mixed with 20 mg of triamcinolone, and checked the pain intensity before and two weeks after the procedure by using visual analogue scale (VAS). RESULTS: In the L4-5 RD group (n=30), contrast spread over the L4 nerve root in 27 cases and the L4 and L5 nerve roots in 3 cases. In the L5-S1 RD group (n=33), contrast spread over the L5 nerve root in 20 cases, the S1 nerve root in 3 cases, and the L5 and the S1 nerve roots in 10 cases. The contrast spreading patterns could be divided into 4 patterns: the proximal root in 40 cases, the distal root in 19 cases, the anterior epidural space in 3 cases and an undefined pattern in 1 case. CONCLUSION: In RD lumbar TF-EPB, the contrast dye mostly went into the cephalic root and about 60% spread over the proximal nerve root. There was less pain reduction when the contrast dye spread over the distal nerve root.

Retrodiscal Approach of Lumbar Epidural Block

OBJECTIVE: To compare the technical strengths and weaknesses between retrodiscal (RD) and conventional subpedicular (SP) approaches of transforaminal epidural block (TF-EPB). METHOD: Sixty-one patients with L5 radiculopathy who planned to undergo TF-EPB were consecutively enrolled as study subjects. Subjects were randomly assigned to one of two groups. For the RD approach, the positioning of the patient and the C-arm were similar to that for lumbar discography. We compared the pattern of dye spreads, the frequency of complications during the procedures, and the effect of the pain block 2 weeks after the procedure between the two groups. RESULTS: For the RD group (n=24), the contrast dye diffused around the L5 and S1 nerve roots in 16 cases (67%), but it diffused around only the L5 root in 27 cases (73%) in the SP group (n=37) (p<0.05). Two weeks after the procedure, the visual analogue scale (VAS) decreased by the same amount in both groups (RD group: 3.1+/-1.6, SP group: 3.2+/-2.6). Symptoms of nerve root irritation occurred in 1 case of the RD group and in 10 cases of the SD group (p<0.05). CONCLUSION: The RD approach was as efficient as the SP approach for temporary diagnostic relief and offered considerable advantages, such as lower nerve root irritation possible lower risk of vascular injection. Thus, it could be a useful technique when a herniated disc segment is stuck or when the foraminal stenosis is severe.

A research for the relative signal intensity of the retrodiscal tissue in the temporomandibular joint disorder patients on MRI

Relative signal intensity of retrodiscal tissue in mri, and synovial fluid concentration of interleukin-6, mmp-2 and mmp-9 in temporomandibular joint disorder

In the progression of the Temporomandibular Joint Disorder(TMD), not only deformation and perforation of disc occur. But also fibrotic adhesion and inflammatory changes to the retrodiscal tissue can be seen in addition to the condylar degenerative change (e.g. osteoarthritis). However, the correct diagnosis,?planning for appropriate treatment, and prediction of prognosis are limited, because there are no means to stage the progression of the disorder. In this study relative signal intensity of retrodiscal tissue in MRI and the synovial fluid concentration of matrix metalloproteinase-2 (MMP-2), MMP-9, and Interleukin-6 (IL-6) in the 23 temporomandibular joints(TMJ), from 17 patients with TMD were evaluated as a possible diagnostic marker. The relative signal intensity of retrodiscal tissue was referenced to brain gray matter with same region of interest(ROI) size. The concentrations of MMP-2, MMP-9, and IL-6 were evaluated by Enzyme Linked Immunosorbent Assay (ELISA). The collected data were compared with condylar degenerative change, joint effusion and disc position observed in MRI. The relative signal intensity of the retrodiscal tissue was increased significantly when degenerative changes were present. In addition, there was significantly high signal intensity in the presence of a disc displaced without reduction. The concentration of IL-6 was significantly increased when condylar degenerative change was no observed. And there were no changes in the levels of IL-6 according to disc position and joint effusion measurement. Moreover, there were no significant relevance between the concentration of total MMP-2 and active MMP-9 in synovial fluid, relative to degenerative changes in the mandibular condyle, to joint effusion, and to disc position observed on MRI images. In conclusion, the relative signal intensity of the retrodiscal tissue can be regarded as a mean of diagnosing the procession of TMD in a non-invasive manner. But more additional studies are required for the levels of MMP-2. MMP-9, and IL-6 to determine their potentials as a diagnostic marker for TMD.

The relative signal intensity of retrodiscal tissue in TMJ using a T2-weighted MRI

The Mri-Based Comparison Of Normal- And Abnormal-Side Retrodiscal Tissue, And Relationship Between Clinical Examination & The Mri Findings Of Retrodiscal Tissue In Patients With Unilateral Tmj Internal Derangement

The study was performed to investigate the comparison of relative signal intensity of normal- and abnormal-side retrodiscal tissue, and relationship between clinical examination, joint effusion and relative signal intensity of retrodiscal tissue in patients with unilateral TMJ internal derangement. The study group comprised 19 females and 9 males, with a mean age of 29 years. After measurements of the signal intensity were made on the MR imager for the T2 weighted images on retrodiscal tissue and brain gray matter, we calculated relative value and tried to find relationship between clinical examination, joint effusion and relative signal intensity on normal- and abnormal-side. The results are as follows. 1. The gray matter is an appropriate reference point. 2. The relative signal intensity is high significantly in abnormal-side retrodiscal tissue compared with normal-side retrodiscal tissue. 3. The relative signal intensity is high significantly in painful joints compared with nonpainful joints and in joints with joint effusion compared with joints without joint effusion. 4. The relative signal intensity in normal joints, joints with reduction and joints without reduction is increased in order significantly.