Temporomandibular joint arthrocentesis: a technique proposal. Case report

BACKGROUND AND OBJECTIVES: Arthrocentesis is an effective treatment to reduce or eliminate pain, increase maximal interincisal distance, and to eliminate joint effusion in patients with disc displacement without reduction. This study aims to expose and to discuss a new technique proposal of temporomandibular joint arthrocentesis applied in the treatment of a single case of disc displacement without reduction. CASE REPORT: Female patient, 18-year-old patient sought treatment due to joint pain and mouth opening limitation. The maximal interincisal distance was 30.28mm. Magnetic resonance imaging confirmed the diagnosis of disc displacement without reduction with signs of joint effusion in the right temporomandibular joint. Temporomandibular joint arthrocentesis was performed under selective sensory nerve block of the auriculotemporal, the masseteric and posterior deep temporal nerves. Two needles were inserted in the upper compartment of the temporomandibular joint. In the second needle, a transparent catheter was connected into a vacuum pump. Clinically, after the arthrocentesis, the maximal interincisal distance increased to 46.25mm, and the patient referred no more pain. After six months, a magnetic resonance imaging was performed to observe the results, and there were no more signs of joint effusion. CONCLUSION: Temporomandibular joint arthrocentesis was an effective treatment for this patient with disc displacement without reduction. The aspect of this technique that is particularly relevant for clinical practice was the connection of a transparent catheter to a vacuum pump. In fact, it allowed the visualization of the solution fluidity, as well as guides the flow of Temporomandibular joint arthrocentesis: a technique proposal. Case report


INTRODUCTION
The arthrocentesis technique was first described in 1991 by Nitzan, Dolwick and Martinez 1 . It is an effective and minimally invasive method for treatment of several temporoman-Grossmann E, Poluha RL and Leite JP BrJP. São Paulo, 2019 jul-sep;2(3):293-5 dibular joint (TMJ) disorders 2 . It consists of washing the superior compartment of the TMJ without direct visualization. The washing procedure is done with a biocompatible substance, such as saline, which helps the dilution of the local allogenic substances and frees the joint disc by removing the adhesions formed between the surfaces of the disc and the mandibular fossa due to the hydraulic pressure generated by the irrigation process 1,3 . The literature has reported some risks with the conventional technique 3 , such as facial nerve paresis, by anesthetic block 4 . Also, there is a risk of extravasation of the liquid used during the irrigation to the surrounding tissue; since there is no guarantee that even using two needles, it is not possible to wash out all the liquid inside. Such risks can be avoided by modifying the technique. This study aims to expose and discuss a technical proposal of temporomandibular joint arthrocentesis.

CASE REPORT
Female patient, 18-year-old, sought treatment due to joint pain and mouth opening limitation. No relevant medical condition was reported. The patient had a history of clicking sound in her right TMJ for the past 10 years. The click disappeared one year ago. Since then, the patient has been unable to open her mouth completely and complained of localized pain in the right TMJ region. On clinical examination, the maximal interincisal distance was 30.28mm with a jaw deflected to the affected side during the opening. Also, the patient was able to perform a normal lateral movement to the affected side. However, there was a limited, painful lateral excursion to the unaffected side. A magnetic resonance imaging (MRI) was requested and the diagnosis of disc displacement without reduction (DDWOR) with signs of joint effusion in the right TMJ was confirmed. The left TMJ did not show clinical or MRI dysfunction. The patient did not respond well to the conservative treatment provided for three months (splint, anti-inflammatory drugs, soft diet, and individualized physiotherapy). Thus, a TMJ arthrocentesis was performed by an experienced maxillofacial surgeon. Clinically, after the arthrocentesis, the maximal interincisal distance increased to 46.25mm, with no more pain. The patient was followed for 7, 14, 30, 60, 90, 180, and 360 days after the procedure. No complications were reported. The results were maintained in all follow-ups. A new MRI was performed 180 days after the arthrocentesis. There were no more signs of joint effusion in the right TMJ. The left TMJ remained unchanged.

Description of the arthrocentesis technique
In the presented case, the arthrocentesis was performed only once in the right TMJ. A demographic pen was used to draw a straight line from the middle portion of the tragus to the corner side of the eyeball, and two points were marked on this line for the insertion of the needles. The first, the most posterior one, at 10mm from the tragus and 2mm below the corner-tragus line. The second one was inserted 20mm anterior to the tragus and 10mm inferior to the corner-tragus line. After waiting for about 3 minutes for the ink to dry, antisepsis of the whole face was performed with chlorhexidine solution at 2%, with emphasis on the preauricular region and ear. Then, a sterile ball of gauze was placed next to the external acoustic meatus, and the whole face was covered by a sterile fenestrated surgical drape, only exposing the joint. The next step was the auriculotemporal nerve block, followed by the anesthesia of the masseteric and posterior deep temporal nerves with lidocaine chloride at 2% without vasoconstrictor 1:100.000, with a total volume of 3.6mL. The patient was asked to open his mouth to its maximum to allow the jaw head to move down and forward, facilitating the approach to the posterior recess of the upper TMJ compartment. A 40x12mm needle connected to a 5mL syringe was inserted into the first mark, and 4mL of saline solution at 0.9% was administered to distend the joint space. A second needle was introduced into the distended compartment, at the point established before, and connected to a #20 flexible and transparent catheter (60cm) connected to a vacuum pump (Kavo ® , Joinville, Santa Catarina, Brazil), which allowed the visualization of the solution. Afterward, an infusion extender, 15C of 120cm (Compojet ® , Conceição do Jacuípe, Bahia, Brazil), was connected to a 60mL syringe to allow the joint lysis and lavage. A total of 300mL of physiological solution was used for the TMJ arthrocentesis. No other substance or drug was added to the solution being injected. Once the procedure was completed, the needles were removed, and the patient was asked to perform opening and lateral movements of the mouth in order to break down any possible disc adherences, in attempt to restore an improved mandibular mobility pattern. Local dressing was conducted with sterile gauze and micropore. On the post-procedure protocol for analgesia, paracetamol (750mg) every 6 hours orally was suggested for a maximum of three days if necessary and an ice pack to be applied to the intermittently intervened joint for a period of 48 hours. In addition, the patient was advised to take liquid and pasty foods for 96 hours, not to expose himself to the sun, and to undergo no medical/dental procedure while recovering (Figures 1 and 2).

DISCUSSION
Arthrocentesis is effective to decrease ou eliminate pain, increase maximal interincisal distance, and to eliminate joint effusion in patients with DDWOR [5][6][7][8][9] . A draw of a straight line from the middle portion of the tragus to the corner side of the eyeball and anatomical references are enough to mark the two points of insertion of the needles. The literature showed that ultrasound-guided arthrocentesis was no more successful than the conventional technique and took longer 10 . The auriculotemporal nerve block, followed by the anesthesia of the masseteric and posterior deep temporal nerves was aimed to avoid the discomfort and/or pain due to the hydraulic pressure that could occur at the beginning of the joint washing procedure, thus obtaining excellent analgesia of the region, avoiding the need for sedation. The literature shows inconclusive advantages of performing arthrocentesis under general anesthesia 11 . In addition, our proposed anesthetic sequence reduces the chance of facial nerve paresis because injection is given directly into the trigeminal nerve branches and not intraarticularly into the temporomandibular joint. The reduction of the pain, the increase of mouth opening, and the reduction of joint effusion are expected as the irrigation process allows the removal of debris of the joint tissues in degeneration process and helps to eliminate the allogenic substances inside the TMJ (mainly, inflammatory mediators) 1,12,13 . Also, the arthrocentesis performed under pressure may help to remove adherences, eliminate the negative pressure in the joint with the distention the joint space, recovering the space of the joint disc and fossa, and changing the viscosity of the synovial liquid that helps the translation of the joint disc and condyle 3,14 .
One of the advantages of the technique proposed in this paper is the use of a flexible and transparent catheter connected to the second needle and a vacuum pump. This appliance allows the visualization of the solution and the fluidity, guides the flow of solution used for joint washing and optimize irrigation regardless of the volume used. Physically this can be explained by the pressure difference 15 inside and outside of the TMJ during the arthrocentesis. Once the irrigation solution is injected into the upper compartment, a pressure difference is created in relation to the external environment. Thus, the pressure inside the upper compartment gets much higher than on the outside. Due to the tendency to restore the pressure balance, the irrigation solution tends to come out of the upper compartment through the second needle. The efficiency of this process is accentuated by the vacuum pump, that also promotes other benefits already mentioned. Also, it can possibly reduce the risk of extravasation of solution used during irrigation, that already has been associated with a negative effect on the success of the procedure 16 .

CONCLUSION
Arthrocentesis is a simple, less invasive, and highly effective procedure. The aspect of this technique that is particularly relevant for clinical practice is the optimization of irrigation. However, new studies are necessary to compare different protocols of irrigation with and without the associated use of a vacuum pump.