Mandibular locking due to bilateral coronoid process hyperplasia

A systematic review of treatment and outcomes in patients with mandibular coronoid process hyperplasia

Treatment of mandibular coronoid process hyperplasia (MCPH) has been described and explored in the literature. This systematic review aims to provide a comprehensive overview of the surgical and non-surgical treatment options for MCPH in pediatric and adult populations. Three databases were searched for treatment of MCPH patients (MEDLINE, Embase, and Web of Science). Two reviewers selected case reports and case series based on titles and abstracts. Finally, 55 studies reporting a total of 127 cases were included for qualitative synthesis and data extraction. The mean age at symptom onset was 15.6 years, while the mean age at diagnosis was 23.5 years. Of the included cases, 83.7% were male, and the condition was bilateral in more than 81% of the cases. Coronoidectomy was performed in 82.7% of the included cases, while coronoidotomy was performed in 3.9% of the cases. In 85.0% of the surgically treated cases, the approach was intraoral. The mean maximal intraoperative mouth opening was 38.1 mm compared with 16.5 mm at diagnosis. The mean maximal postoperative mouth opening was 35.3 mm, and the mean follow-up period was 16.3 months. Maximum mouth opening was achieved intraoperatively, and non-surgical treatment after surgery aims to reduce the risk of relapse. Additional research with a higher level of evidence is necessary to confirm these findings.

Coronoid hyperplasia: A review

Coronoid hyperplasia is one of the rare causes of progressive limitation of mouth opening due to impingement of the enlarged coronoid process of the mandible on the zygomatic bone. A review was performed on all cases reports and case series on coronoid hyperplasia. Gender, age at treatment, age of onset, types of hyperplasia (unilateral/bilateral), associated history, treatment, surgical approach, preoperative mouth opening, intraoperative mouth opening, mouth opening at follow up and follow up period were recorded and analyzed. A total of 82 articles which reported 115 cases were included. Coronoid hyperplasia was commonly reported at mean age of 22.64 years old with male preponderance. Most of the cases were diagnosed and treated between the age of 11-20 years old. This condition commonly involved bilateral coronoid process of mandible. The mean width of preoperative mouth opening was 16.5mm and was improved to a mean mouth opening of 36.3mm intraoperatively. Mean mouth opening was 34.8mm at an average follow up of 19 months. While the etiopathogenesis of coronoid hyperplasia is still not conclusive, treatment with either coronoidectomy or coronoidotomy produced good improvement in mouth opening.

Successful Treatment of Postoperative Mouth Opening Limitation Following Le Fort III Distraction with Bilateral Coronoidectomies

INTRODUCTION

Distraction osteogenesis is a powerful tool in craniomaxillofacial surgery, allowing for large advancements of osteotomized segments in the setting of a restrictive soft tissue envelope. Despite its benefits, distraction can have negative functional consequences. We present a case of a patient with Crouzon syndrome who developed reduced mouth opening capability after a Le Fort III midfacial advancement with rigid external distraction.

TECHNIQUE

Radiographic evaluation revealed that the coronoid process was restricting the normal excursion of the mandible by contacting the posterior zygoma. The patient was subsequently treated with a bilateral coronoidectomy via an intraoral approach, which improved his interincisal opening. Maximum interincisal distance was improved from 18 mm to 33 mm following bilateral cornoid resection.

CONCLUSION

We report coronoid impingement as a potential complication after Le Fort III distraction. Such a finding suggests the need for a detailed vector analysis in cases undergoing midface advancement with distraction. Post-distraction coronoidectomy is a useful surgical procedure to treat mouth opening limitation due to coronoid impingement against the zygoma after midfacial advancement.