Anatomical marking device for access to the lower compartment of the temporomandibular joint

Abstract

The present utility model, named "TMJ Access Point", relates to an innovative device designed to overcome the challenges associated with safe and precise access to the lower compartment of the temporomandibular joint (TMJ). The device is made from a flexible polymeric or metallic material and adjusts perfectly to the facial morphology of the patient, ensuring a stable and comfortable fit. Its main advantage lies in the incorporation of standardized anatomical markings and reference orifices, which allow the exact demarcation of the critical points for performing minimally invasive procedures, such as infiltrations and viscosupplementation. This device eliminates dependence on subjective measurements, thereby making the procedures standardized and reproducible. This standardization also reduces variations between practitioners and minimizes risks, increasing the precision and safety of access to the lower compartment of the TMJ. In addition, the device simplifies preparation for the procedure, optimizing clinical workflow and reducing the procedure time. Furthermore, by making it possible to perform procedures with greater accuracy, the device enhances therapeutic efficacy, reducing complications and promoting more reliable and consistent treatment, which results in improved quality of life for patients.

Description

Anatomical marking device for access to the lower compartment of the temporomandibular joint.

[0001] This utility model patent refers to a device called "ATM Access Point," developed to facilitate access to the lower compartment of the Temporomandibular Joint (TMJ) by marking key anatomical points – based on the viscosupplementation technique. The device's structure comprises a flexible ruler with rounded ends and precise markings that provide reproducibility and standardization to clinical procedures, reducing the need for additional equipment such as ultrasound. Furthermore, the device is adaptable to different anatomical configurations, reducing the margin of error in procedures, contributing to improved clinical outcomes, reducing complications, and promoting more reliable and consistent treatment, which translates into a higher quality of life for patients. Description of the prior art:

[0002] The Temporomandibular Joint, commonly known simply as TMJ, is the joint that connects the temporal bone of the skull to the mandible, playing an essential role in functions such as chewing, swallowing, and speaking. It is one of the most complex joints in the human body, as it not only allows rotational and translational movements, but is also supported by a wide network of muscles, ligaments, and adjacent structures that need to work in harmony. Although many people don't realize how much the TMJ is required in everyday tasks, a few disorders in this region are enough to highlight its importance. Problems such as chronic pain, joint clicking, limited mouth opening, headaches of muscular origin, and even discomfort in the cervical spine can be associated with temporomandibular dysfunctions, leading a significant number of patients to seek specialized medical and dental help.

[0003] Motivation for studying and improving techniques involving the temporomandibular joint (TMJ) has been increasing as research demonstrates the correlation between the proper functioning of this joint and the individual's quality of life. Although several TMJ-related pathologies are initially controlled with conservative techniques such as the use of occlusal splints, physiotherapy, drug therapy, and lifestyle recommendations, there are cases where it is necessary to intervene directly in the joint, either through arthrocentesis, drug infiltration, or the application of more recent techniques such as viscosupplementation.From this perspective of minimally invasive treatment, one of the main obstacles faced by dentists and oral and maxillofacial surgeons lies in the precise identification of the lower compartment of the joint, where, in certain situations, the application of therapeutic fluids, drugs, or viscous substances can offer pain relief, reduction of intra-articular friction, and stimulation of tissue recovery.

[0004] The difficulty in accurately locating this lower compartment stems both from the specific anatomical position of the TMJ in the face and from the morphological variability among patients. Although the upper compartment is relatively more accessible, the lower compartment requires precise angulation at the time of needle insertion so that the professional does not hit adjacent structures and can effectively reach the joint space, located just below the disc that separates the two synovial chambers. In current clinical practice, the most traditional way to locate the access point is to use digital palpation of anatomical landmarks, such as the preauricular depression and the roof of the articular fossa, and estimate angles and distances that allow reaching the desired location.In some centers, ultrasound is used as an imaging guide, facilitating the visualization of internal structures, but the dependence on equipment and specific training for this technique means that not all professionals or clinics have access to this resource.

[0005] The result is that, in the absence of a universal marking standard and simple, reliable auxiliary equipment, identifying the exact point for accessing the lower compartment of the TMJ often relies fundamentally on the individual experience of each professional. While more experienced dentists or highly trained oral and maxillofacial surgeons tend to have greater accuracy, clinicians in the learning phase or who do not perform the procedure frequently run a greater risk of making mistakes in angulation and location. Consequently, slips can occur that lead to various complications, such as injecting drugs into adjacent soft tissues instead of inside the joint, increasing patient discomfort, prolonging the procedure time and, in more critical scenarios, potentially inducing inflammation or more serious damage to the region.Furthermore, the difficulty in standardizing access point marking hinders the development of robust scientific protocols, as location and depth variables can influence treatment efficacy, preventing reliable comparisons between different clinical studies.

[0006] In this context, the development of a device that simplifies the precise identification of the access point to the lower compartment of the temporomandibular joint (TMJ) appears to be a natural response to the problems faced by dentists and surgeons. However, after an extensive review of the state of the art, no technologies or patent applications were identified that incorporate the characteristics of the device claimed herein. Existing solutions, while aiming to facilitate procedures in the TMJ, fail to provide, in a universal, precise, and reproducible manner, the anatomical points necessary to access the lower compartment of this joint. This premise is supported by the following description of the most relevant patent applications found, which are:

[0007] Brazilian patent BR 1020150192134 describes an arthroscopic suturing system structured as a set of disposable instruments organized into two main groups, encompassing both trocars (with tips of different shapes and functions) and auxiliary triangulation devices. The objective is to enable the movement and control of the tips within the temporomandibular joint (TMJ), facilitating suturing and treatment of injured articular tissues. The invention stands out for its ergonomic handles, needle tips with varied profiles (piercing, banana knife type, blunt, and scraping), and a guide triangulator that directs the positioning of the instruments in the joint.

[0008] Brazilian patent BR 1020230166555 proposes a device for triangulating instruments and equipment used in minimally invasive TMJ surgical procedures. It consists of a small polymer body (approximately 20x20x20 mm) with three equidistant holes positioned at a 120-degree angle to each other. When placed externally over pre-established incisions on the patient's face, the device promotes ideal alignment between the arthroscope and surgical tools. This aims to improve the efficiency of procedures such as arthroscopy and reduce the complexity of instrument handling.

[0009] CN220046721U describes a marking ruler primarily aimed at the upper compartment of the TMJ. The device features a main body, equipped with lateral rods and marking tips, that aligns with the lateral corner of the eye and the intertragic notch, simplifying the process of delimiting the needle insertion point for injection into the upper cavity. This proposal emphasizes the practicality of the method, eliminating the need for extensive drawings and measurements on the patient's face, allowing for direct marking through the tips that press against the skin.

[0010] In contrast to the aforementioned solutions, the "ATM Access Point" is specifically designed for accessing the lower compartment of the TMJ, a region with greater anatomical complexity that requires more precise location for therapeutic injections. Unlike triangulation systems that prioritize the introduction of surgical instruments, or rulers that focus on the upper compartment, the flexible ruler proposed here incorporates defined anatomical markings to position the insertion points in the lower chamber, reducing dependence on image guides and the individual experience of the professional. The flexibility of the material, combined with the scales and reference holes, ensures better adaptation to the face and a reproducible procedure, allowing the professional to perform the marking uniformly, even in varying anatomies.Furthermore, the "ATM Access Point" is not limited to surgical assistance or suturing, but rather to the precise delimitation of puncture sites, standing out as a more comprehensive and simplifying tool for minimally invasive techniques that require access to the lower compartment of the TMJ. Brief description of the objectives

[0011] As explained, the main objective of the "ATM Access Point" is to facilitate rational, safe, fast, and highly precise access to the lower compartment of the TMJ, seeking to standardize procedures and minimize the margin of error in anatomical marking. More specifically, the device aims to universalize and standardize the marking of points necessary for therapeutic or diagnostic infiltration, offering reference scales and orifices that reduce dependence on imaging techniques, additional equipment, or the individual experience of the professional. The details and functionalities can be better understood by the following detailed description in accordance with the attached figures, where: Figure 1 refers to a schematic representation of the ANATOMICAL MARKING DEVICE, in front view, identifying the anatomical points (1), (2), (3), (4) and (5), which correspond to the exact positions for marking the reference points. Figure 2 shows the rear view of the device. Figure 3 shows an isometric representation of the apparatus, identifying the same reference points (1), (2), (3), (4) and (5). Detailed description of the invention:

[0012] The ANATOMICAL MARKING DEVICE FOR ACCESS TO THE LOWER COMPARTMENT OF THE TEMPOROMANDIBULAR JOINT, as described, is a flexible access ruler designed to provide precise guidance in identifying key points in the preauricular region and the lateral orbital region, optimizing minimally invasive clinical procedures and ensuring greater accuracy during TMJ interventions. The development of the device was based on practical observations, data collected during studies on the treatment of pathologies affecting the joint, and anatomical guidelines described in the specialized literature.

[0013] In particular, the "ATM Access Point" was developed from the findings reported by Januzzi et al. (2022) - [Januzzi, E., Cunha, TCA, Silva, G., Souza, BDM, Duarte, ASB, Zanini, MRS, Andrade, AM, Pedrosa, AR, Custódio, ALN, & Castro, MAA (2022). Viscosupplementation in the upper and lower compartments of the temporomandibular joint checked by ultrasonography in an ex vivo and in vivo study. Scientific Reports, 12(1), 17976)]. This study showed that anatomical standardization of the puncture site contributes to greater precision in the deposition of the viscous agent, reducing deviations and risks associated with the procedure. It was also observed that this standardization helps minimize inflammatory complications, in addition to favoring the reproducibility of clinical results.Thus, the flexible ruler was designed to incorporate these findings, ensuring precise anatomical alignment of the reference points described in the technique, improving the safety and efficiency of TMJ access procedures.

[0014] The device's core functionality stems from its flexible anatomical ruler shape, which features precise markings corresponding to the distances established in the Viscosupplementation technique and other TMJ approach protocols. The device follows the natural curvature of the region near the ear, resting on the patient's skin while the professional identifies the preauricular depression and the roof of the articular fossa. This extensively studied area is considered a key reference point, usually called Point (1) in most TMJ access techniques, including the one cited in the study by Januzzi et al. From this initial point, the professional is instructed to align the ruler with the lateral region of the orbit, in order to correctly mark the additional points that serve as a guide for articular access.

[0015] Points (2) and (3) are marked 5 mm and 10 mm before Point (1), respectively, which requires well-defined linear measurements. The "ATM Access Point" fulfills this need by having graduations and holes in the body of its ruler that correspond exactly to these distances. This provides a high degree of reliability and reduces dependence on manual estimates or digital palpation, factors that, in isolation, could result in inaccurate markings. Once the line connecting Point (1) to the lateral contour of the orbit is drawn, the so-called P-OL line (lateral orbit point) is identified, on which Points (2) and (3) are located. Next, Points (4) and (5), located 7 mm below the previous points, are marked perpendicularly to the P-OL line. To facilitate this perpendicular positioning, the ruler is provided with angle guides that allow the user to position the ruler on the correct axis without the need for additional instruments.

[0016] In terms of construction, the ruler body can be made from medical-grade polymers or malleable metal alloys. The use of thermoplastics, such as polypropylene or polycarbonate, in the preferred version, has been validated in clinical settings due to its satisfactory mechanical resistance and ability to withstand repeated sterilizations without permanent deformation. This material is compatible with autoclave processes, ethylene oxide sterilization, or immersion in disinfectant solutions, maintaining the metric scales and the overall structure of the device intact. When a metallic version is chosen, stainless steel or titanium alloys are usually used, as they combine characteristics of mechanical resistance, moderate flexibility, biocompatibility, and low susceptibility to corrosion.

[0017] Furthermore, the device's ends are intentionally rounded to prevent injury to the patient or harm to the professional during use. Additionally, this design simplifies the cleaning process, as there are no sharp edges or corners where residue can accumulate. The design also considers how the professional handles the ruler, accommodating both right- and left-handed users. Therefore, the grip on the device is intuitive, regardless of who is using it, allowing for fluid point marking and angle adjustment.

[0018] The ruler itself has a series of guides and holes that serve the main purpose of locating and marking the exact anatomical points on the face. In certain versions, these holes are approximately 1 to 2 mm in diameter, a size sufficient for the passage of a sterile marker (dermatographic pen or surgical pencil), allowing the user to precisely mark the puncture site. Thus, the risk of slippage or deviation during marking is minimal, as the surface of the device acts as a stable guide. Furthermore, the ruler has linear or angular markings that indicate the correct positioning for drawing straight or perpendicular lines along the skin, according to the technique described in clinical protocols and in the study by Januzzi et al.

[0019] Due to this standardization, the procedure time is significantly reduced. With the "TMJ Access Point," the professional does not need to resort to successive manual measurements or advanced imaging techniques (such as ultrasound) to confirm each access point. Although imaging exams can be useful in certain scenarios, they require complex equipment and additional time, which can compromise the dynamics in a busy clinical environment. By using the device, the surgeon or dentist immediately obtains the precise access locations to the lower compartment of the TMJ, simply by following the alignment instructions provided. This increases efficiency and reduces the error rate, bringing important clinical benefits such as reduced inflammatory complications and greater predictability of therapeutic results.

[0020] Regarding its use, the device proves to be highly versatile. Its application is not limited to viscosupplementation, but extends to infiltrations of local anesthetics in oral surgical procedures, collection of synovial fluid for laboratory analysis, and other interventions in the temporomandibular joint (TMJ). In all these cases, standardized anatomical marking plays a fundamental role in minimizing the risk of tissue damage and ensuring that the needle, cannula, or other instrument is inserted exactly where desired. This feature is especially relevant in cases of temporomandibular dysfunction with atypical anatomies, as the flexible ruler adapts to different facial structures, maintaining the reliability of the measurements.

[0021] In practice, the professional positions the device so that the protrusion or orifice corresponding to Point (1) coincides with the preauricular depression identified by palpation. The other end of the device is directed towards the lateral contour of the orbit, defining the P-OL line. According to the specific instructions, Points (2) and (3) are located 5 mm and 10 mm anterior to Point (1), and then perpendicular markings are made to identify Points (4) and (5), located 7 mm below the previous points. The graduations and angle guides on the ruler body have been calibrated to make this procedure simple, intuitive, and reproducible by different users. As a result, the final position of each point will be practically the same, regardless of minor variations in the patient's anatomy or the professional's handling style, ensuring homogeneity in clinical results.

[0022] In terms of customization, the device can be adjusted to the needs of different patient profiles or different clinical protocols. Such adjustments include changing metric scales (for example, reducing spacing for shorter patients or increasing these intervals in cases of wider anatomies), adding additional graduations, or altering the standard tilt angle for special applications. These variations do not change the functional scope of the device but broaden its applicability in different clinical scenarios. However, standardization of use recommends that the most widely used versions follow anatomical parameters corroborated by studies with a broad statistical basis, ensuring reliability even in scientific research reports or more complex applications. Example of Implementation of the Invention

[0023] To illustrate its use, consider the procedure of injecting an anti-inflammatory drug into the lower compartment of the TMJ in patients with chronic pain or severe joint dysfunction. The oral and maxillofacial surgeon palpates the preauricular depression, establishing Point (1). Then, the "TMJ Access Point" is positioned to trace the P-OL line, locating Points (2) and (3) 5 mm and 10 mm anterior to Point (1). Next, the ruler is adjusted perpendicularly to that line to mark Points (4) and (5), which are located 7 mm below the corresponding points. Once the marks on the patient's face are determined, the needle or cannula is inserted at the precisely established locations, increasing the chances of reaching the lower compartment without deviations or perforations in adjacent tissues. This degree of accuracy, made possible by the standardization of distances and angles, reduces the occurrence of inflammation, bleeding, or poorly positioned injections.

[0024] For further clarification, it should be noted that the protective scope described here is not limited to the exemplary configurations presented. Constructive variations, scale adjustments, the use of different materials, and other modifications that do not alter the operating principle should be considered covered by the protection afforded to the "ATM Access Point".

Claims

CLAIMS 1. ANATOMICAL MARKING DEVICE FOR ACCESS TO THE LOWER COMPARTMENT OF THE TEMPOROMANDIBULAR JOINT, with an elongated and flexible ruler-shaped body, equipped with graduations and reference holes, featuring ends designed to reduce the risk of tissue injury and intended to facilitate the identification of anatomical points on the patient's face, characterized by an ergonomic design that allows the device to fit naturally over the lateral region of the face, minimizing variations in positioning and facilitating the reading of the scales and the alignment of points for access to the lower compartment of the TMJ, also comprising the following characteristics: • An orifice (1) positioned to correspond to the main anatomical point of the preauricular depression, aligned with the roof of the articular fossa; • A guide line associated with linear graduations, extending to the lateral region of the orbit, defining, by means of metric indications, the marking of points (2) and (3) at predetermined distances in relation to Point (1), preferably 5 mm and 10 mm before it; • Angle guides that allow perpendicular marking, from points (2) and (3), ensuring the exact definition of additional points (4) and (5) located 7 mm below the previous points; • Marking holes distributed along linear and perpendicular sections, with a diameter sufficient for the passage of a sterile marking instrument, enabling the faithful transfer of anatomical references to the skin.

2. ANATOMICAL MARKING DEVICE FOR ACCESS TO THE LOWER COMPARTMENT OF THE TEMPOROMANDIBULAR JOINT, according to claim 1, characterized by including metric markings in low or high relief, corresponding to reference distances of 5 mm, 10 mm and 7 mm, arranged in such a way as to allow the sequential identification of the anatomical points necessary to access the lower compartment of the TMJ.

3. ANATOMICAL MARKING DEVICE FOR ACCESS TO THE LOWER COMPARTMENT OF THE TEMPOROMANDIBULAR JOINT, according to claim 1, characterized by having rounded ends designed to prevent injury to the patient's tissue during positioning, ensuring greater safety and comfort in clinical handling.

4. ANATOMICAL MARKING DEVICE FOR ACCESS TO THE LOWER COMPARTMENT OF THE TEMPOROMANDIBULAR JOINT, according to claim 1, characterized by having variations in scale or metric increments, aiming to adapt to different anatomical profiles of patients, while maintaining unchanged the technical-functional unit of anatomical marking for access to the lower compartment of the TMJ.

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