Bilateral hyperplasia of the mandibular coronoid processes: a report of two cases

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.

Trismus Due to Hyperplastic Coronoid Process: Series of Five Cases and Review of Literature

ABSTRACT

Hyperplasia of the coronoid process is a rare condition, potentially leading to a mechanical mouth opening restriction. Diagnostic workup and treatment will be discussed based on 5 cases. This article presents 5 cases of true coronoid process hyperplasia. In addition, we reviewed accessible literature on the topic with special attention to pathophysiologic theories, surgical approach, and postoperative physiotherapy. The improvement in the maximal intercuspidal opening ranged from 4 and 31 mm. Greater maximal intercuspidal opening improvement was connected to compliant patients, while poor outcome occurred in the case of a patient that neither followed the recommendations for physical therapy nor showed up for his follow up appointments. The success of the therapy is defined by a long-lasting and stable improvement of the mouth opening compared to the preoperative situation. In the presented cases, the outcome was strongly dependent on the patients' postoperative compliance. Based on the cases described, we conclude that a good outcome is accomplishable for patients using the methods presented, as long as patients cooperate well after surgery.Diagnostic workup in patients with trismus should be thorough to correctly diagnose rare entities such as coronoid hyperplasia. If treated correctly this condition has a good outcome, as long as the compliance of the patient is adequate.

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.

Bilateral Hyperplasia of the Coronoid Process in Pediatric Patients: What is the Gold Standard for Treatment?

OBJECTIVES

The aim of this systematic review of the literature is to describe treatment options for bilateral coronoid process hyperplasia in pediatric patients, to describe etiologic and diagnostic correlations with the treatment, and to evaluate long-term follow-up treatment outcomes.

METHODS

A systematic revision of the literature was performed in the Medline, PubMed, Cochrane library, and Embase database up to December 5, 2017. Predetermined Medical Subject Heading keywords were used: "bilateral" or "monolateral" and "coronoid" or "coronoid process" and "hyperplasia" and "temporomandibular joint" or "tmj" and "ankylosis" or "trismus" and "treatment." Results were recorded following PRISMA guidelines.

RESULTS

The systematic research produced 1459 results excluding duplicates. Two additional studies from "Grey literature" were also considered. After application of inclusion and exclusion criteria, 38 articles were selected for a qualitative synthesis. Data regarding sex and age of presentation were collected and summarized in a study flow diagram.

CONCLUSION

It is possible to conclude that early diagnosis is fundamental to restore stomatognathic multifunction. There is lack of longitudinal studies presenting long-term follow-up to determine treatment stability. Coronoidectomy might be considered gold standard treatment for this pathologic condition.

Masticatory muscle tendon-aponeurosis hyperplasia: A new clinical entity of limited mouth opening

Limited mouth opening is a common health problem that interferes with eating, makes examination of the oral cavity difficult, and may increase the mortality rate during emergency intubation. Here we introduce a disease designated as masticatory muscle tendon-aponeurosis hyperplasia, which is a new clinical condition of limited mouth opening. Most oral surgeons and dentists are still unaware of this disease condition, thus increasing the risk of incorrect diagnosis as some other disease, such as temporomandibular joint disorder. We will review the clinical features, epidemiology, pathophysiology, etiology, diagnosis, treatment, and prognosis of this disease and also appraise the literature available on the subject.

Trismus Due to Bilateral Coronoid Hyperplasia

Bilateral coronoid hyperplasia causes painless progressive trismus, resulting from coronoid process impingement on the posterior aspect of the zygomatic bone. The etiology of coronoid hyperplasia is unclear, with various theories proposed. An endocrine stimulus, increased temporalis activity, trauma, genetic inheritance and familial occurrence have all been proposed, but no substantive evidence exists to support any of these hypotheses. Multiplanar reformatting of axial scans and 3-dimensional reconstruction permit precise reproduction of the shape and size of the coronoid and malar structures, and relationships of all structures of the temporal and infratemporal fossae. This case shows remarkably increased mouth opening by coronoidectomy in a patient who complained of trismus due to hyperplasia of coronoid process.

Elongated Mandibular Coronoid Process As a Cause of Mandibular Hypomobility

There are multiple factors in cases of mandibular hypomobility. One of these factors is elongated coronoid process. Two cases are presented to illustrate elongated coronoid process leading to mandibular hypomobility to help prevent misdiagnosis by clinicians. Coronoid process elongation is a rare condition. Both cases reported here had pulpitis on the teeth, however endodontic treatment could not be performed due to the restricted mouth opening in both cases. There were clinical findings of restricted range of motion, especially during protrusive movements. The restrictive movements did not cause pain for either patient, and the patients were not aware of their restricted mouth opening. Panoromic radiographs were taken and evaluated. The radiographs showed elongated coronoid process bilaterally. Three-dimensional computerized tomography was taken in one case only, due to the patient's financial restrictions. In cases of restricted mandibular opening, elongated coronoid process must be considered when diagnosing the cause.

Mandibular coronoid hyperplasia in pediatric patients

Bilateral coronoid hyperplasia is a relatively rare condition in the pediatric population and yet may be an unrecognized cause of limited mouth opening in children. There are multiple theories as to the causes of the hyperplasia, which include temporalis hyperactivity, hormonal stimulus, and genetic inheritance. The resulting excess growth of the coronoids results in impingement on the zygomatic processes leading to mandibular hypomobility. The diagnosis is confirmed with plain films and computed tomography scans. Treatment involves bilateral coronoidectomies to relieve impingement on the zygoma. Postoperative physical therapy is crucial for success; the therapy focuses on maintaining the mouth opening achieved at the time of surgery. Outcome reports have been variable despite good physical therapy, suggesting that the exact pathology of the condition is not well understood.

Hyperplasie des Processus coronoideus: Diagnose und Therapie

STUDY GOAL

As it is an unusual and infrequent clinical entity, hyperplasia of the coronoid process is often overlooked or diagnosed too late. The aim of this study was to characterize the morphology, etiology, and clinical picture of coronoid hyperplasia as well as to discuss its diagnosis and treatment.

MATERIALS AND METHODS

All cases of histologically confirmed hyperplasia of the coronoid process treated in our center between 1995 and 2004 were analyzed. Patient data were evaluated with respect to age, gender, clinical symptoms, diagnostic work-up, and treatment. The extracted data were compared to those found in the literature.

RESULTS

The study included 14 new cases and 101 cases already published: 96 with bilateral and 19 with unilateral hyperplasia. At the time of diagnosis, the subjects' mean age was 23.7 years. The patients in Bonn were all treated by coronoidectomy and appropriate physiotherapy. An improvement in mouth opening could be achieved in 86% of our patients.

CONCLUSIONS

In comparison to the somewhat disappointing results of previously published studies with regard to mouth opening and mandibular mobility, our treatment concept seems to offer the possibility for improvement. Our study emphasizes the significance of three-dimensional CT techniques for diagnosis and surgical planning, the superiority of coronoidectomy over coronoidotomy, and the importance of dynamic physiotherapy to prevent postoperative scar formation.

Bilateral coronoid hyperplasia in two brothers

Coronoid hyperplasia is a rare condition of unknown aetiology that can occur in both unilateral and bilateral forms. Without radiographic investigation the diagnosis is often missed. Researchers have postulated a familial form of inheritance. This study reports the occurrence of coronoid hyperplasia in two brothers. The parents were unaffected and there are no other siblings. The diagnosis was confirmed with the aid of panoramic radiographs and axial computed tomographic scans with para-sagittal reconstructions which demonstrated enlargement of the coronoid processes and in one case impingement against the zygomatic bone. One brother was successfully treated with a unilateral intra-oral coronoidectomy whilst the other was unsuccessfully treated with a bilateral intra-oral coronoidectomy.

Electromyographic activity of the jaw-closing muscles before and after unilateral coronoidectomy performed on a patient with coronoid hyperplasia: a case study

There have been few reports analyzing the activity of the jaw-closing muscles after coronoidectomy performed on a patient with coronoid hyperplasia. This paper presents a case study using electromyograms (EMGs) to evaluate the effects of unilateral coronoidectomy on the activity of masseter and temporal muscles. The patient was a 25-year-old male whose maximal range of jaw opening was 24 mm. After coronoidectomy of the left region, the range improved to 43 mm. EMGs were recorded in the center of the masseter muscles and the anterior part of the temporal muscles during gum chewing. Preoperatively, no abnormal EMG activity was observed. Eight months after surgery, increase in the ratio of the bilateral temporal muscle activity and a decrease in the ratio of the right masseter muscle activity were observed, and the proportion of activity of jaw closing muscles was out of the normal range. Eighteen months after surgery, there was slight return to the preoperative EMG activity. It was concluded that unilateral coronoidectomy could result in EMG changes of masseter and temporal muscles with a gradual return.

Hyperplasia of the mandibular coronoid process: long-term follow-up after coronoidotomy

The aim of this study was to evaluate long-term results of treatment by intraoral coronoidotomy and prolonged physiotherapy in five patients with mandibular coronoid process hyperplasia. Five consecutive cases of coronoid process hyperplasia were studied (two unilateral and three bilateral) at the Department of Maxillo-facial Surgery of the University of Turin during the period 1985-1990. All patients were treated by intraoral coronoidotomy and given physiotherapy from the third postoperative day. This continued for an entire year. A clinical and radiological follow-up (average 39.4 months), in three cases over a 5-year period, was completed. Three months after the operation, all patients had achieved satisfactory improvement in mandibular interincisal opening. The mean value for mouth opening at the end of follow-up was 42 mm. Radiographic follow-up showed the presence of a coronoid process almost the size of the original, apparently united with the mandibular ascending ramus, with moderate dislocation and inclination posterior to the body of the zygomatic bone. The results of this study indicate that treatment of coronoid process hyperplasia by intraoral coronoidotomy, when combined with prolonged postoperative physiotherapy, gives satisfactory and stable long-term results in the correction of coronoid-malar interference.

Case report: computed tomography in the investigation of bilateral mandibular coronoid hyperplasia

Bilateral mandibular coronoid hyperplasia is characterized by restricted mouth opening due to impingement of the coronoid processes on the zygomatic arches. The condition is unfamiliar to many clinicians and may be significantly under-reported. The presented case highlights the benefits of computed tomography (CT) in the diagnosis and surgical evaluation of this disorder.

Hyperplasia of the mandibular coronoid process: an analysis of 31 cases and a review of the literature

PURPOSE

This study was undertaken to investigate the demographic and clinical features of mandibular coronoid hyperplasia and to assess the response to current treatments.

PATIENTS AND METHOD

Case notes were studied and records made of age, sex, duration of symptoms, operative procedures, and response to treatment in all patients presenting at the Queen Victoria Hospital, East Grinstead, over a 20-year period from 1970 to 1990 with a confirmed diagnosis of mandibular coronoid hyperplasia.

RESULTS

Thirty-one cases were recorded, 23 bilateral and 8 unilateral. The average age on presentation was 27.8 years for bilateral and 23.6 years for unilateral cases, with symptoms predating presentation by an average of 9 years and 6.75 years, respectively. Surgery was disappointing in terms of improving mouth opening.

CONCLUSION

The results of this large series are supported by meta-analysis of the previous literature. They suggest that surgical management may be improved by a greater understanding of the pathogenesis of this condition.

Recurrent bilateral coronoid hyperplasia: an unusual case

A case of bilateral coronoid hyperplasia is presented. The possible aetiology of this rare condition is discussed. This case is unusual in that true synovial joints were demonstrated bilaterally between the coronoid processes and the zygomatic bones and following a bilateral coronoidectomy, the coronoid hyperplasia with marked limitation of jaw opening fully recurred, which has not been described previously. After a further coronoidectomy with return of function to the temporomandibular joints, a change from a retrognathic mandibular relationship to a gross prognathic position occurred. The management problems encountered with this case are discussed along with a documented account of the treatment provided over a 12-year period.

Bilateral coronoid hyperplasia. Report of two cases and review of the literature

Two cases of bilateral hyperplasia of the coronoid processes of the mandible are presented. The patients were men and first noticed their symptoms at 14 and 10 years of age, respectively. They were treated successfully by intraoral bilateral coronoidectomies. A review of the literature revealed only forty-nine cases of the condition reported; 43 cases in western countries and 6 in Japan. As described previously, the majority of the cases were men and their symptoms occurred under the age of 19 years.