Arthroscopy-Assisted Inferior Compartment Arthrocentesis of the Temporomandibular Joint

Arthroscopy-Assisted Inferior Compartment Arthrocentesis of the Temporomandibular Joint | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Arthroscopy-Assisted Inferior Compartment Arthrocentesis of the Temporomandibular Joint Romualdo Cardoso Monteiro De Barros, Lucas Maia Nogueira, Helcio Yogi Ono This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8855336/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Purpose Arthroscopic lysis and lavage of the temporomandibular joint (TMJ) is an established treatment for internal derangements (ID). Conventional techniques are limited to the superior compartment, although pathologies and translational movement frequently involve the inferior compartment. This study describes and evaluates a reproducible needle-based arthroscopic-assisted technique for lysis and lavage of the inferior compartment. Methods Twenty patients with Wilkes IV, anterior disc displacement without reduction, and condylar resorption confirmed on MRI/CT were prospectively treated. Two 18G needles were introduced through arthroscopic view on the lateral discal transitional zone into the inferior compartment, enabling lavage with 100 mL of Ringer’s solution. Superior compartment lavage were subsequently performed, followed by injection of high-molecular-weight hyaluronic acid. Outcomes included pain (Visual Analog Scale, VAS) and mandibular motion (maximum mouth opening and laterality). Results VAS scores decreased from 5.55 ± 2.92 preoperatively to 0.35 ± 0.92 postoperatively (Δ − 5.20; p < 0.001). A ≥ 3-point pain reduction was achieved in 85% of patients, and 95% ended ≤ 2. Maximum mouth opening improved by + 4.25 ± 4.19 mm (95% CI 2.32–6.18). Right and left laterality improved by + 3.45 ± 2.89 mm and + 2.55 ± 2.31 mm, respectively, with 85–90% of patients showing increased excursions. No major complications occurred. Conclusion Arthroscopy-assisted technique provides safe and effective access to the inferior TMJ compartment, yielding significant improvements in pain and motion. It avoids greater damage to fibrocartilage, is a cost-effective and reproducible technique, and expands minimally invasive therapeutic options for advanced internal derangements. temporomandibular joint arthroscopy lysis and lavage inferior compartment minimally invasive surgery Figures Figure 1 Figure 2 Figure 3 Introduction Arthroscopic lysis and lavage of the temporomandibular joint (TMJ) has been demonstrated as an effective method for reducing pain and improving mouth opening compared with conventional conservative treatments 1 . Internal derangements (ID) of the TMJ, such as Wilkes stages II, III, and IV 2 , are among the main indications for arthroscopic lysis and lavage, which involves the removal of adhesions and lavage of the superior joint space. Although morphologic changes are well documented in the superior joint compartment, some studies suggest that these alterations are even more prevalent in the inferior joint compartment 3 . Goss (2019) 4 reported that at least 50% of the pathology and the predominant site of translational movement are located in the inferior joint compartment, which may limit the clinical outcomes of superior compartment arthroscopy alone. These findings highlight the potential role of the inferior joint compartment in the development of ID 5 . With the exception of cases with disc perforation or disc absence, the inferior compartment cannot be visualized through conventional TMJ arthroscopy. Here, we describe an alternative method for arthroscopic lysis and lavage of the inferior joint compartment, applied in 20 clinical cases of patients with advanced internal derangement classified as Wilkes stage IV. Patients and Methods Inclusion criteria: Patients with TMD Symptoms, Anterior disc displacement without reduction along with condylar bone resorption and decorticalization confirmed on MRI and CT, with previous clinical managing with oclusal splints and general clinical conditions to support general anesthesia. Exclusion criteria: Patients with Anterior disc displacement with reduction, with no inferior compartment imaginological findings or without previous clinical managing. This study was approved by the Institutional Review Board (IRB) of the Instituto de Ensino e Pesquisa Bucomaxilofacial (Sao Paulo, Brazil). All participants provided informed consent, and the study adhered to the Declaration of Helsinki on medical ethics, with approval from the regional Ethical Review Board. Surgical technique All procedures were performed under general anesthesia with nasotracheal intubation. After insufflation of the superior joint compartment with 2 mL of ropivacaine, a 1.9 mm, 30° optic (Anton Hipp, Germany) was introduced through a trocar. Outflow was established via a 16G needle placed 5 mm above and 5 mm anterior to the optic trocar. A sweeping exploration of the superior compartment was performed. Figure 1 . For the inferior compartment arthrocentesis, two additional 18G needles were inserted, located 5 mm and 10 mm anterior to the 16G needle, respectively. Both 18G needles were initially visualized in the superior compartment and then advanced into the lateral discal transitional zone of the inferior compartment. Once bone contact was achieved, a slight upward adjustment of the needle tip was performed to create space for lavage. Approximately 100 mL of Ringer’s solution was used for inferior compartment lavage. Figure 2 and 3 . Following inferior compartment arthrocentesis, adhesions were removed and lavage of the superior joint compartment was completed. Finally, high molecular weight hyaluronic acid was injected into the superior compartment. Statistical Analysis Table 1 . Table 1 Pre- and postoperative patient data for mandibular motion (maximum mouth opening and lateral movements, in millimeters) and Visual Analog Scale (VAS) scores for pain. Motion Improvement after inferior compartment lysis and lavage (mm) VAS Patient MMO LAT (right) LAT (left) Pre op Post op 1 15 5 4 7 0 2 1 6 5 0 0 3 6 -4 1 4 0 4 1 5 3 3 0 5 -3 1 3 7 0 6 2 3 1 0 0 7 3 4 5 2 0 8 1 1 -1 0 0 9 8 2 1 6 0 10 7 2 2 8 0 11 0 6 5 6 0 12 13 4 1 8 4 13 4 -2 1 5 0 14 4 8 8 8 0 15 1 3 2 6 0 16 3 3 3 7 0 17 4 4 1 3 0 18 0 4 -1 3 0 19 3 2 2 10 1 20 8 5 5 10 2 Data were analyzed using paired within-subject comparisons. Continuous variables are reported as mean ± standard deviation (SD) or median [IQR], as appropriate. Because range and symmetry of the paired differences were acceptable (Shapiro–Wilk on VAS differences), we present both parametric and nonparametric tests for robustness: paired t-test and Wilcoxon signed-rank test (one-sided for the hypothesis that post-operative VAS < pre-operative VAS). For motion variables (MMO and laterality), only the change (Δ, mm) was available; these are summarized descriptively with 95% confidence intervals (CI) for the mean. A clinically meaningful pain response was defined as a ≥ 3-point reduction in VAS. Results In this study twenty patients with previous TMJ Arthroscopy with inferior compartment lysis and lavage were analyzed for clinical pain and motion outcomes. Regarding the pain (VAS). Mean VAS decreased from 5.55 ± 2.92 pre-operatively to 0.35 ± 0.92 post-operatively. The mean paired change (post − pre) was − 5.20 (95% CI − 6.43 to − 3.97). Normality of paired differences was acceptable (Shapiro–Wilk p = 0.0013 indicates non-normality; thus both tests are reported); the reduction was highly significant on the paired t-test (p < 0.000001) and on the Wilcoxon signed-rank test (p < 0.000001, one-sided). The standardized paired effect size (Cohen’s dz) was − 1.64, indicating a large effect. A ≥ 3-point VAS reduction occurred in 17/20 (85.0%) patients. Post-operative VAS ≤ 2 was observed in 19/20 (95.0%). Regarding the maximum mouth opening (MMO): mean Δ 4.25 ± 4.19 mm (95% CI 2.32 to 6.18); median 3.50 [1.00–6.00]; range − 3 to 15. Improved (> 0 mm) in 17/20 (85.0%), worsened in 2, unchanged in 1. Laterality right: mean Δ 3.45 ± 2.89 mm (95% CI 2.13 to 4.77); median 3.50 [2.00–5.00]; range − 4 to 8. Improved in 18/20 (90.0%), worsened in 2, unchanged in 0. Laterality left: mean Δ 2.55 ± 2.31 mm (95% CI 1.50 to 3.60); median 2.00 [1.00–3.00]; range − 1 to 8. Improvedin 18/20 (90.0%), worsened in 2, unchanged in 0. Discussion Understanding osteoarthritis of the TMJ increasingly requires addressing the inferior compartment, since inflammatory mediators such as cytokines (IL-6, TNF-α, among others) are expressed more prominently in this space. If left untreated, degenerative processes in the condyle can progress to significant volume loss, severely compromising prognosis and long-term outcomes. Several techniques have been described for accessing the inferior compartment. Due to its considerably smaller volume compared with the superior compartment, it remains a technical challenge for TMJ surgeons 6 . Ultrasound-guided infiltrations have shown promise in confirming inferior compartment access; however, their widespread adoption is limited by the high cost of equipment, the need for specialized training, and a steep learning curve. Conventional arthroscopic techniques also rely on optics that are often too large for the reduced space, increasing the risk of iatrogenic damage to the fibrocartilage, thereby worsening degeneration and limiting therapeutic benefit 7 , 8 . de Barros and Ono (2024) reported the use of 0.9 mm fiber optics for direct inspection of the inferior compartment, combined with superior compartment arthroscopy. Although this expands therapeutic possibilities, it still requires dedicated video systems for the inferior compartment, increasing procedural costs 9 . The technique described in this study not only enables lysis and lavage of the inferior compartment—already proven to have therapeutic benefits—but also allows for adjunctive procedures such as viscosupplementation with hyaluronic acid and platelet-rich fibrin 10 . This arthroscopy-assisted access to the inferior compartment demonstrated clinically meaningful gains: VAS decrease from 5.55 ± 2.92 to 0.35 ± 0.92, with 85% achieving a ≥ 3-point reduction and 95% ending ≤ 2; motion also improved (ΔMMO 4.25 ± 4.19 mm; right/left laterality + 3.45 ± 2.89 mm / +2.55 ± 2.31 mm), with 85–90% showing better excursions. Practically, the needle-based approach through the lateral discal transitional zone created a safe working space for lavage without introducing bulky optics into a small recess, preserving fibrocartilage and leveraging the same setup used for superior arthroscopy. This makes the technique equipment-sparing, reproducible, and readily adoptable, while still accommodating adjuncts such as hyaluronic-acid viscosupplementation or platelet-rich fibrin. Limitations include the single-arm design, potential confounding from concomitant superior arthroscopy and rehabilitation, and motion reported as changes (Δ) rather than absolute functional thresholds. Even so, the 48-month durability and consistency across pain and excursion outcomes support selective use when symptoms or lateral movements remain refractory after superior-space treatment, or when imaging suggests inferior capsular adhesions. Future work should quantify the incremental benefit in comparative trials (superior-only vs. combined approaches), incorporate compartment-specific biomarkers to clarify mechanisms and responders, and standardize reporting (absolute MMO, responder definitions, and adverse events) to refine indications and long-term expectations. In conclusion, this method represents a simple, cost-effective, and reproducible technique that opens promising avenues for minimally invasive treatment of advanced TMJ pathology. Declarations Competing Interests: The authors have no relevant financial or non-financial interests to disclose Consent to participate Informed consent was obtained from all individual participants included in the study. Funding: The authors declare that no funds, grants, or other support were received during the preparation of this manuscript Author Contribution All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Helcio Ono, Romualdo Cardoso Monteiro de Barros and Lucas Nogueira. The first draft of the manuscript was written by Romualdo Cardoso Monteiro de Barros and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript References Slater H The effectiveness of TMJ minimally invasive treatment. In: International Conference on TMJ Biology, Diagnosis and Surgical Management. October 4-5th, 2012. Groningen, The Netherlands Wilkes CH (1989) Internal derangements of the temporomandibular joint: pathological variations. Arch Otolaryngol Head Neck Surg 115:469–477 Kondoh T, Westesson PL, Takahashi T, Seto K (1998) Prevalence of morphological changes in the surfaces of the temporomandibular joint disc associated with internal derangement. J Oral Maxillofac Surg 56:339–343 Goss NA et al (2019) A modified Technique of Temporomandibular Joint Arthroscopic Operative Surgery of the Superior and Inferior Joint Spaces. J. Maxillofac. Oral Surg. (Oct–Dec 2020) 19(4):561–570 Slater H The effectiveness of TMJ minimally invasive treatment. In: International Conference on TMJ Biology, Diagnosis and Surgical Management. October 4-5th, 2012. Groningen, The Netherlands Kondoh T, Westesson PL (1991) Diagnostic accuracy of temporomandibular joint lower-compartment arthroscopy using an ultrathin arthroscope: a postmortem study. J Oral Maxillofac Surg. 49(6):619 – 26. 10.1016/0278-2391(91)90344-l . PMID: 2037918 Goss NA et al (2019) A modified Technique of Temporomandibular Joint Arthroscopic Operative Surgery of the Superior and Inferior Joint Spaces. J. Maxillofac. Oral Surg. (Oct–Dec 2020) 19(4):561–570 González-García R, Moreno-Sánchez M, Moreno-García C, Román-Romero L, Monje F (2018) Arthroscopy of the Inferior Compartment of the Temporomandibular Joint: A New Perspective. J Maxillofac Oral Surg 17(2):228–232. 10.1007/s12663-017-1023-x Epub 2017 May 31. PMID: 29618891; PMCID: PMC5878166 de Barros RCM, Ono HY (2025) Simultaneous arthroscopy of upper and lower compartments of the temporomandibular joint. Int J Oral Maxillofac Surg 54(2):174–178 Epub 2024 De Nordenflycht D, Ayala A, Orellana L, Tesch RS (2023) Intra-articular injections in the TMJ inferior joint space: A scoping review. J Oral Rehabil 50(11):1316–1329. 10.1111/joor.13542 Epub 2023 Jun 26. PMID: 37323068 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 10 Mar, 2026 Reviewers agreed at journal 26 Feb, 2026 Reviewers invited by journal 25 Feb, 2026 Editor assigned by journal 16 Feb, 2026 Submission checks completed at journal 16 Feb, 2026 First submitted to journal 11 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8855336","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":597529311,"identity":"2b3708dc-fc13-4eb0-aff2-48f46a31fbb6","order_by":0,"name":"Romualdo Cardoso Monteiro De Barros","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABC0lEQVRIiWNgGAWjYDCCA1CajyGBDcJibwASBhaEtbDBtfCAhAwkSNEikQAmcergu32A7cPHnMPybOzJxx783HNPTn7m86sbfhRIMPC3dydg0yJ5LoF55sxthw3beJ6lG/Y8KzY2uJ1TdrMH6DCJM2c3YNNicIaBmZl322HGNokcMwmeAwmJG6Rz0m7wALUYSOTi1WIP0iL5B6hl/swzaTf/EKElEaRFGmRLww32Y7fx2SJ5hrGZcea29GSQX4xlDiQYG5zJYbstYyDBg8svfGeYDzN83GZt2w8MsYdvDiTIybcff3bzzR8bOf72XqxaGBgYG9BFeAzAJHbl2AH7A1JUj4JRMApGwfAHABNzYnpd4rL3AAAAAElFTkSuQmCC","orcid":"","institution":"Hospital Sirio Libanes","correspondingAuthor":true,"prefix":"","firstName":"Romualdo","middleName":"Cardoso Monteiro","lastName":"De Barros","suffix":""},{"id":597529312,"identity":"e274f232-f2d3-496c-8ab3-d292f897e813","order_by":1,"name":"Lucas Maia Nogueira","email":"","orcid":"","institution":"hospital Nipo brasileiro","correspondingAuthor":false,"prefix":"","firstName":"Lucas","middleName":"Maia","lastName":"Nogueira","suffix":""},{"id":597529313,"identity":"fc73087c-aff1-43b3-bdc5-698da4fdbfbc","order_by":2,"name":"Helcio Yogi Ono","email":"","orcid":"","institution":"Hospital Sirio Libanes","correspondingAuthor":false,"prefix":"","firstName":"Helcio","middleName":"Yogi","lastName":"Ono","suffix":""}],"badges":[],"createdAt":"2026-02-11 20:08:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8855336/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8855336/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104169063,"identity":"558cd349-501e-403c-b2ad-30507497556d","added_by":"auto","created_at":"2026-03-08 14:37:43","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":372654,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic illustration of: A – 1.9 mm optic in the posterior recess of the upper joint space; B – 16G needle for outflow lavage of the upper compartment; C – first 18G needle for inflow into the inferior compartment; D – 18G needle for outflow from the inferior compartment. All needles are placed within a 5 mm interval.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8855336/v1/39ec15a926ec4a66d7c3609f.jpeg"},{"id":104169064,"identity":"9204b129-c05d-4650-bf33-f5a450c0df00","added_by":"auto","created_at":"2026-03-08 14:37:43","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":552158,"visible":true,"origin":"","legend":"\u003cp\u003eIntraoperative view of inferior compartment arthrocentesis. The outflow through the smaller-caliber needle confirms proper lavage of the inferior compartment.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8855336/v1/e7566f01097713a667dea9cd.jpeg"},{"id":104169065,"identity":"fce9bfa5-2bae-4eeb-bb70-3acead0a10a7","added_by":"auto","created_at":"2026-03-08 14:37:43","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":603486,"visible":true,"origin":"","legend":"\u003cp\u003eArthroscopic view of the posterior recess of the upper compartment, showing correct placement of two 18G needles for arthrocentesis of the inferior compartment.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8855336/v1/e385770f29356befc6a51028.jpeg"},{"id":104169066,"identity":"9c3d90b8-63d8-4beb-b369-5f58af6efb2b","added_by":"auto","created_at":"2026-03-08 14:37:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1991161,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8855336/v1/79f34042-d74d-44b0-bb27-c131ca8d7fbf.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Arthroscopy-Assisted Inferior Compartment Arthrocentesis of the Temporomandibular Joint","fulltext":[{"header":"Introduction","content":"\u003cp\u003eArthroscopic lysis and lavage of the temporomandibular joint (TMJ) has been demonstrated as an effective method for reducing pain and improving mouth opening compared with conventional conservative treatments\u003csup\u003e1\u003c/sup\u003e. Internal derangements (ID) of the TMJ, such as Wilkes stages II, III, and IV\u003csup\u003e2\u003c/sup\u003e, are among the main indications for arthroscopic lysis and lavage, which involves the removal of adhesions and lavage of the superior joint space. Although morphologic changes are well documented in the superior joint compartment, some studies suggest that these alterations are even more prevalent in the inferior joint compartment\u003csup\u003e3\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eGoss (2019)\u003csup\u003e4\u0026nbsp;\u003c/sup\u003ereported that at least 50% of the pathology and the predominant site of translational movement are located in the inferior joint compartment, which may limit the clinical outcomes of superior compartment arthroscopy alone. These findings highlight the potential role of the inferior joint compartment in the development of ID\u003csup\u003e5\u003c/sup\u003e. With the exception of cases with disc perforation or disc absence, the inferior compartment cannot be visualized through conventional TMJ arthroscopy.\u003c/p\u003e\n\u003cp\u003eHere, we describe an alternative method for arthroscopic lysis and lavage of the inferior joint compartment, applied in 20 clinical cases of patients with advanced internal derangement classified as Wilkes stage IV.\u003c/p\u003e"},{"header":"Patients and Methods","content":"\u003cp\u003eInclusion criteria: Patients with TMD Symptoms, Anterior disc displacement without reduction along with condylar bone resorption and decorticalization confirmed on MRI and CT, with previous clinical managing with oclusal splints and general clinical conditions to support general anesthesia.\u003c/p\u003e \u003cp\u003eExclusion criteria: Patients with Anterior disc displacement with reduction, with no inferior compartment imaginological findings or without previous clinical managing.\u003c/p\u003e \u003cp\u003eThis study was approved by the Institutional Review Board (IRB) of the \u003cem\u003eInstituto de Ensino e Pesquisa Bucomaxilofacial\u003c/em\u003e (Sao Paulo, Brazil). All participants provided informed consent, and the study adhered to the Declaration of Helsinki on medical ethics, with approval from the regional Ethical Review Board.\u003c/p\u003e\n\u003ch3\u003eSurgical technique\u003c/h3\u003e\n\u003cp\u003eAll procedures were performed under general anesthesia with nasotracheal intubation. After insufflation of the superior joint compartment with 2 mL of ropivacaine, a 1.9 mm, 30\u0026deg; optic (Anton Hipp, Germany) was introduced through a trocar. Outflow was established via a 16G needle placed 5 mm above and 5 mm anterior to the optic trocar. A sweeping exploration of the superior compartment was performed.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eFor the inferior compartment arthrocentesis, two additional 18G needles were inserted, located 5 mm and 10 mm anterior to the 16G needle, respectively. Both 18G needles were initially visualized in the superior compartment and then advanced into the lateral discal transitional zone of the inferior compartment. Once bone contact was achieved, a slight upward adjustment of the needle tip was performed to create space for lavage. Approximately 100 mL of Ringer\u0026rsquo;s solution was used for inferior compartment lavage.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFollowing inferior compartment arthrocentesis, adhesions were removed and lavage of the superior joint compartment was completed. Finally, high molecular weight hyaluronic acid was injected into the superior compartment.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePre- and postoperative patient data for mandibular motion (maximum mouth opening and lateral movements, in millimeters) and Visual Analog Scale (VAS) scores for pain.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eMotion Improvement after inferior compartment lysis and lavage (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eVAS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatient\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMMO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLAT (right)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLAT (left)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePre op\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePost op\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eData were analyzed using paired within-subject comparisons. Continuous variables are reported as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) or median [IQR], as appropriate. Because range and symmetry of the paired differences were acceptable (Shapiro\u0026ndash;Wilk on VAS differences), we present both parametric and nonparametric tests for robustness: paired t-test and Wilcoxon signed-rank test (one-sided for the hypothesis that post-operative VAS\u0026thinsp;\u0026lt;\u0026thinsp;pre-operative VAS). For motion variables (MMO and laterality), only the change (Δ, mm) was available; these are summarized descriptively with 95% confidence intervals (CI) for the mean. A clinically meaningful pain response was defined as a\u0026thinsp;\u0026ge;\u0026thinsp;3-point reduction in VAS.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eIn this study twenty patients with previous TMJ Arthroscopy with inferior compartment lysis and lavage were analyzed for clinical pain and motion outcomes.\u003c/p\u003e \u003cp\u003eRegarding the pain (VAS). Mean VAS decreased from 5.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.92 pre-operatively to 0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92 post-operatively. The mean paired change (post\u0026thinsp;\u0026minus;\u0026thinsp;pre) was \u0026minus;\u0026thinsp;5.20 (95% CI\u0026thinsp;\u0026minus;\u0026thinsp;6.43 to \u0026minus;\u0026thinsp;3.97). Normality of paired differences was acceptable (Shapiro\u0026ndash;Wilk p\u0026thinsp;=\u0026thinsp;0.0013 indicates non-normality; thus both tests are reported); the reduction was highly significant on the paired t-test (p\u0026thinsp;\u0026lt;\u0026thinsp;0.000001) and on the Wilcoxon signed-rank test (p\u0026thinsp;\u0026lt;\u0026thinsp;0.000001, one-sided). The standardized paired effect size (Cohen\u0026rsquo;s dz) was \u0026minus;\u0026thinsp;1.64, indicating a large effect. A\u0026thinsp;\u0026ge;\u0026thinsp;3-point VAS reduction occurred in 17/20 (85.0%) patients. Post-operative VAS\u0026thinsp;\u0026le;\u0026thinsp;2 was observed in 19/20 (95.0%).\u003c/p\u003e \u003cp\u003eRegarding the maximum mouth opening (MMO): mean Δ 4.25\u0026thinsp;\u0026plusmn;\u0026thinsp;4.19 mm (95% CI 2.32 to 6.18); median 3.50 [1.00\u0026ndash;6.00]; range\u0026thinsp;\u0026minus;\u0026thinsp;3 to 15. Improved (\u0026gt;\u0026thinsp;0 mm) in 17/20 (85.0%), worsened in 2, unchanged in 1. Laterality right: mean Δ 3.45\u0026thinsp;\u0026plusmn;\u0026thinsp;2.89 mm (95% CI 2.13 to 4.77); median 3.50 [2.00\u0026ndash;5.00]; range\u0026thinsp;\u0026minus;\u0026thinsp;4 to 8. Improved in 18/20 (90.0%), worsened in 2, unchanged in 0. Laterality left: mean Δ 2.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.31 mm (95% CI 1.50 to 3.60); median 2.00 [1.00\u0026ndash;3.00]; range\u0026thinsp;\u0026minus;\u0026thinsp;1 to 8. Improvedin 18/20 (90.0%), worsened in 2, unchanged in 0.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eUnderstanding osteoarthritis of the TMJ increasingly requires addressing the inferior compartment, since inflammatory mediators such as cytokines (IL-6, TNF-α, among others) are expressed more prominently in this space. If left untreated, degenerative processes in the condyle can progress to significant volume loss, severely compromising prognosis and long-term outcomes.\u003c/p\u003e \u003cp\u003eSeveral techniques have been described for accessing the inferior compartment. Due to its considerably smaller volume compared with the superior compartment, it remains a technical challenge for TMJ surgeons\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eUltrasound-guided infiltrations have shown promise in confirming inferior compartment access; however, their widespread adoption is limited by the high cost of equipment, the need for specialized training, and a steep learning curve. Conventional arthroscopic techniques also rely on optics that are often too large for the reduced space, increasing the risk of iatrogenic damage to the fibrocartilage, thereby worsening degeneration and limiting therapeutic benefit\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ede Barros and Ono (2024) reported the use of 0.9 mm fiber optics for direct inspection of the inferior compartment, combined with superior compartment arthroscopy. Although this expands therapeutic possibilities, it still requires dedicated video systems for the inferior compartment, increasing procedural costs\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe technique described in this study not only enables lysis and lavage of the inferior compartment\u0026mdash;already proven to have therapeutic benefits\u0026mdash;but also allows for adjunctive procedures such as viscosupplementation with hyaluronic acid and platelet-rich fibrin\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThis arthroscopy-assisted access to the inferior compartment demonstrated clinically meaningful gains: VAS decrease from 5.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.92 to 0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92, with 85% achieving a\u0026thinsp;\u0026ge;\u0026thinsp;3-point reduction and 95% ending\u0026thinsp;\u0026le;\u0026thinsp;2; motion also improved (ΔMMO 4.25\u0026thinsp;\u0026plusmn;\u0026thinsp;4.19 mm; right/left laterality\u0026thinsp;+\u0026thinsp;3.45\u0026thinsp;\u0026plusmn;\u0026thinsp;2.89 mm / +2.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.31 mm), with 85\u0026ndash;90% showing better excursions. Practically, the needle-based approach through the lateral discal transitional zone created a safe working space for lavage without introducing bulky optics into a small recess, preserving fibrocartilage and leveraging the same setup used for superior arthroscopy. This makes the technique equipment-sparing, reproducible, and readily adoptable, while still accommodating adjuncts such as hyaluronic-acid viscosupplementation or platelet-rich fibrin.\u003c/p\u003e \u003cp\u003eLimitations include the single-arm design, potential confounding from concomitant superior arthroscopy and rehabilitation, and motion reported as changes (Δ) rather than absolute functional thresholds. Even so, the 48-month durability and consistency across pain and excursion outcomes support selective use when symptoms or lateral movements remain refractory after superior-space treatment, or when imaging suggests inferior capsular adhesions. Future work should quantify the incremental benefit in comparative trials (superior-only vs. combined approaches), incorporate compartment-specific biomarkers to clarify mechanisms and responders, and standardize reporting (absolute MMO, responder definitions, and adverse events) to refine indications and long-term expectations.\u003c/p\u003e \u003cp\u003eIn conclusion, this method represents a simple, cost-effective, and reproducible technique that opens promising avenues for minimally invasive treatment of advanced TMJ pathology.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting Interests:\u003c/h2\u003e \u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eConsent to participate\u003c/h2\u003e \u003cp\u003e Informed consent was obtained from all individual participants included in the study.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Helcio Ono, Romualdo Cardoso Monteiro de Barros and Lucas Nogueira. The first draft of the manuscript was written by Romualdo Cardoso Monteiro de Barros and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSlater H The effectiveness of TMJ minimally invasive treatment. In: International Conference on TMJ Biology, Diagnosis and Surgical Management. October 4-5th, 2012. Groningen, The Netherlands\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWilkes CH (1989) Internal derangements of the temporomandibular joint: pathological variations. Arch Otolaryngol Head Neck Surg 115:469\u0026ndash;477\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKondoh T, Westesson PL, Takahashi T, Seto K (1998) Prevalence of morphological changes in the surfaces of the temporomandibular joint disc associated with internal derangement. J Oral Maxillofac Surg 56:339\u0026ndash;343\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGoss NA et al (2019) A modified Technique of Temporomandibular Joint Arthroscopic Operative Surgery of the Superior and Inferior Joint Spaces. J. Maxillofac. Oral Surg. (Oct\u0026ndash;Dec 2020) 19(4):561\u0026ndash;570\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSlater H The effectiveness of TMJ minimally invasive treatment. In: International Conference on TMJ Biology, Diagnosis and Surgical Management. October 4-5th, 2012. Groningen, The Netherlands\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKondoh T, Westesson PL (1991) Diagnostic accuracy of temporomandibular joint lower-compartment arthroscopy using an ultrathin arthroscope: a postmortem study. J Oral Maxillofac Surg. 49(6):619\u0026thinsp;\u0026ndash;\u0026thinsp;26. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/0278-2391(91)90344-l\u003c/span\u003e\u003cspan address=\"10.1016/0278-2391(91)90344-l\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 2037918\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGoss NA et al (2019) A modified Technique of Temporomandibular Joint Arthroscopic Operative Surgery of the Superior and Inferior Joint Spaces. J. Maxillofac. Oral Surg. (Oct\u0026ndash;Dec 2020) 19(4):561\u0026ndash;570\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGonz\u0026aacute;lez-Garc\u0026iacute;a R, Moreno-S\u0026aacute;nchez M, Moreno-Garc\u0026iacute;a C, Rom\u0026aacute;n-Romero L, Monje F (2018) Arthroscopy of the Inferior Compartment of the Temporomandibular Joint: A New Perspective. J Maxillofac Oral Surg 17(2):228\u0026ndash;232. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s12663-017-1023-x\u003c/span\u003e\u003cspan address=\"10.1007/s12663-017-1023-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003eEpub 2017 May 31. PMID: 29618891; PMCID: PMC5878166\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ede Barros RCM, Ono HY (2025) Simultaneous arthroscopy of upper and lower compartments of the temporomandibular joint. Int J Oral Maxillofac Surg 54(2):174\u0026ndash;178 Epub 2024\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDe Nordenflycht D, Ayala A, Orellana L, Tesch RS (2023) Intra-articular injections in the TMJ inferior joint space: A scoping review. J Oral Rehabil 50(11):1316\u0026ndash;1329. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/joor.13542\u003c/span\u003e\u003cspan address=\"10.1111/joor.13542\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003eEpub 2023 Jun 26. PMID: 37323068\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"oral-and-maxillofacial-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"omfs","sideBox":"Learn more about [Oral and Maxillofacial Surgery](http://link.springer.com/journal/10006)","snPcode":"10006","submissionUrl":"https://submission.nature.com/new-submission/10006/3","title":"Oral and Maxillofacial Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"temporomandibular joint, arthroscopy, lysis and lavage, inferior compartment, minimally invasive surgery","lastPublishedDoi":"10.21203/rs.3.rs-8855336/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8855336/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eArthroscopic lysis and lavage of the temporomandibular joint (TMJ) is an established treatment for internal derangements (ID). Conventional techniques are limited to the superior compartment, although pathologies and translational movement frequently involve the inferior compartment. This study describes and evaluates a reproducible needle-based arthroscopic-assisted technique for lysis and lavage of the inferior compartment.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eTwenty patients with Wilkes IV, anterior disc displacement without reduction, and condylar resorption confirmed on MRI/CT were prospectively treated. Two 18G needles were introduced through arthroscopic view on the lateral discal transitional zone into the inferior compartment, enabling lavage with 100 mL of Ringer\u0026rsquo;s solution. Superior compartment lavage were subsequently performed, followed by injection of high-molecular-weight hyaluronic acid. Outcomes included pain (Visual Analog Scale, VAS) and mandibular motion (maximum mouth opening and laterality).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eVAS scores decreased from 5.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.92 preoperatively to 0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92 postoperatively (Δ\u0026thinsp;\u0026minus;\u0026thinsp;5.20; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). A\u0026thinsp;\u0026ge;\u0026thinsp;3-point pain reduction was achieved in 85% of patients, and 95% ended\u0026thinsp;\u0026le;\u0026thinsp;2. Maximum mouth opening improved by +\u0026thinsp;4.25\u0026thinsp;\u0026plusmn;\u0026thinsp;4.19 mm (95% CI 2.32\u0026ndash;6.18). Right and left laterality improved by +\u0026thinsp;3.45\u0026thinsp;\u0026plusmn;\u0026thinsp;2.89 mm and +\u0026thinsp;2.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.31 mm, respectively, with 85\u0026ndash;90% of patients showing increased excursions. No major complications occurred.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eArthroscopy-assisted technique provides safe and effective access to the inferior TMJ compartment, yielding significant improvements in pain and motion. It avoids greater damage to fibrocartilage, is a cost-effective and reproducible technique, and expands minimally invasive therapeutic options for advanced internal derangements.\u003c/p\u003e","manuscriptTitle":"Arthroscopy-Assisted Inferior Compartment Arthrocentesis of the Temporomandibular Joint","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-08 14:37:38","doi":"10.21203/rs.3.rs-8855336/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-03-10T17:39:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"143610909979503263078345456053565329621","date":"2026-02-26T11:57:56+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-26T02:33:08+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-16T08:56:04+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-16T08:55:47+00:00","index":"","fulltext":""},{"type":"submitted","content":"Oral and Maxillofacial Surgery","date":"2026-02-11T20:02:20+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"oral-and-maxillofacial-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"omfs","sideBox":"Learn more about [Oral and Maxillofacial Surgery](http://link.springer.com/journal/10006)","snPcode":"10006","submissionUrl":"https://submission.nature.com/new-submission/10006/3","title":"Oral and Maxillofacial Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"3a09e94a-18eb-4eb3-8119-715e49325987","owner":[],"postedDate":"March 8th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-08T14:37:38+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-08 14:37:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8855336","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8855336","identity":"rs-8855336","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}