Idiopathic Condylar Resorption (ICR), aka, “cheerleaders’ syndrome”, is an uncommon aggressive degenerative joint disease that most frequently occurs in teenage girls during the pubertal growth spurt. In patients with ICR, a decrease in the mandibular ramus height occurs during the growth period, resulting in a clockwise mandibular rotation and subsequent anterior open bite. (Iwasa et al, 2022).
- ICR is an aggressive non-inflammatory, non-painful, degeneration of the TMJ.
- ICR can be unilateral or bilateral.
- ICR of one TMJ can influence the development and remodeling of the contralateral healthy condyle.
- “Cheerleaders’ syndrome” is a phrase that has been used to refer to ICR, because teenage girls participating in sports activities are more prone to ICR through minor or major trauma to the jaws.
- The backward rotation of the mandible in ICR cases may jeopardize breathing by reducing the oropharyngeal airway space.
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Theories and possible causes of ICR
Hormonal disturbances: since ICR has a high prevalence among teenage females going through puberty, and since estrogen receptors were identified in the TMJ, this suggests that hormonal disturbances may play a role in the pathogenesis of ICR.
- Dysfunctional remodeling of the TMJ due to:
- Intrinsic factors: reduced adaptive capacity of the TMJ articulating structures in response to mechanical stress.
- Extrinsic factors: microtrauma, parafunctional habits, orthognathic surgery, orthodontic treatment, and pre-existing TMJ internal derangement.
Diagnosis and monitoring of ICR
Diagnosis of ICR should start by evaluating the patient’s history, physical examination, imaging, and blood workup. The Diagnosis of ICR is one of exclusion, and only after eliminating the possibility of all other local and systemic pathological and developmental conditions, a diagnosis of ICR can be made.
While the clinical symptoms of ICR can include TMJ clicking, crepitation, pain, locking, and headache, in many cases pain may be mild or even absent, and the patient’s main complaint will be “progressive changes in the occlusion and facial aesthetics”. In cases where ICR is bilateral, patients will develop a class II occlusion with an anterior open bite. But if ICR is unilateral, the patient will have facial asymmetry, the mandibular dental midline and chin will shift toward the affected side, a class II occlusion will develop on the ipsilateral side, and an open bite will be seen on the contralateral side.
Imaging (CT, CBCT, MRI, SPECT/CT) helps to assess if ICR is active or at arrest by taking a series of TMJ imaging at predetermined intervals (usually every 6 months) and then comparing the changes in the TMJ dimensions over time. A loss in TMJ volume over time indicates an active ICR condition.
The blood workup is necessary to exclude systemic and inflammatory causes for TMJ resorption.
- Differential diagnosis
- Reactive arthritis
- Inflammatory arthritis
ICE Treatment Approaches
The treatment of an active ICR aims to slow down or halt the progression of TMJ resorption, while in cases of ICR arrest the treatment mainly focuses on restoring the occlusion and esthetics.
Management options discussed include oral appliances, orthodontics, medical management, orthognathic surgery with and without disc repositioning, and alloplastic temporomandibular joint replacement. Depending on the severity of the condition and the activity status of the ICR, the proposed treatments include:
- No treatment
2. Treatments for active ICR:
- Condyle repositioning and disc stabilization by attachment to implant
- Condylectomy and costochondral graft.
- Treatments for a no longer active ICR:
- Bilateral sagittal-split osteotomy
- Orthodontic treatment
- Alloplastic reconstruction
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Iwasa, A., Tanaka, E., 2022. Signs, Symptoms, and Morphological Features of Idiopathic Condylar Resorption in Orthodontic Patients: A Survey-Based Study. Journal of Clinical Medicine 11, 1552. doi:10.3390/jcm11061552
Yu, Y., Wang, S., Wu, M., Chen, X., He, F., 2022. Signs and Symptoms of Temporomandibular Dysfunction and Radiographic Condylar Morphology in Patients with Idiopathic Condylar Resorption. Journal of Clinical Medicine 11, 4289. doi:10.3390/jcm11154289
Munakata K, Miyashita H, Nakahara T, Shiba H, Sugahara K, Katakura A, Nakagawa T. The use of SPECT/CT to assess resorptive activity in mandibular condyles. Int J Oral Maxillofac Surg. 2022 Jul;51(7):942-948. doi: 10.1016/j.ijom.2021.11.012. Epub 2021 Dec 20. PMID: 34937677.
Pedersen, T.K., Stoustrup, P., 2021. How to diagnose idiopathic condylar resorptions in the absence of consensus-based criteria?. Journal of Oral and Maxillofacial Surgery 79, 1810–1811. doi:10.1016/j.joms.2021.04.026.
Tanimoto, K., Awada, T., Onishi, A., Kubo, N., Asakawa, Y., Kunimatsu, R., Hirose, N., 2022. Characteristics of the Maxillofacial Morphology in Patients with Idiopathic Mandibular Condylar Resorption. Journal of Clinical Medicine 11, 952. doi:10.3390/jcm11040952
Mercuri LG, Handelman CS. Idiopathic Condylar Resorption: What Should We Do? Oral Maxillofac Surg Clin North Am. 2020 Feb;32(1):105-116. doi: 10.1016/j.coms.2019.09.001. Epub 2019 Nov 1. PMID: 31685348.