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Unilateral hyperplasia of the coronoid process of the mandible
1111. J.
Oral Surg. 1981: 10: 145-147
(Key words: coronoid process; hyperplasia; trauma; surgery. oral)
Unilateral hyperplasia of the coronoid process of the mandible Case report BAHRAM JAVID School of Dental Medicine, Shiraz University, Shiraz, Iran
Unilateral hyperplasia of the coronoid process of the mandible, with the resultant limitation of opening of the mouth, is not a common finding. The exact cause is not known, but etiological factors have been suggested, trauma being the most commonly mentioned. The present patient was involved in a car accident 8 months previously and sustained facial trauma, but without any obvious signs of fracture. ABSTRACT -
(Received for publicatioll 5 March, accepted 25 July 1980)
Unilateral abnormality of the coronoid process of the mandible is one of the causes of limitation of mouth opening. Unilateral coronoid malformation, exostosis, osteoma hyperplasia, hypertrophy and osteochondroma are many names and descriptions given by the authors of over 30 cases reported in the dentalliterature 1 - 9. Trauma is one of the number of etiological factors put forward. Among the other suggested etiological factors are: failure of the cartilagenous growth centers to disappear normally at an early stage of development of the mandible; disturbance in the growth mechanism and vascular disturbances in the coronoid process; increased activity of the temporal muscle, hyperplasia of neoplastic nature and, because of the attached tendon of temporaIis, an osteochondroma lesion of the coronoid process is formed 1 - 9 •
Fractures of the coronoid process of the mandible are not common; they constitute 2 % of all mandibular fractures. Displacement of the fractured segment depends on the line of fracture and pull of the temporalis muscle. ,Displacement of the fractured segment may bring about a locally reactive fibrosis and impingement of the zygomatic arch. Ankylosis of the coronoid process and the zygomatic arch leading to limitation of opening of the mouth has been reported. A number of patients with unilateral hyperplasia of the coronoid process give an history of traumatic or "difficult" tooth extractions. But although other suggestions of possible causes are put forward, no definite single etiological factor is presented.
Case report A 23 year old male presented with a complaint of "inability to open his mouth
0300-9785/81/020145-03$02.50/0 © 1981 Munksgaard, Copenhagen
146
JAVTD
Fig. 1. Limitation of opening of mouth to 11
mm pre-operatively.
fully". He gave a history of a car accident
8 months previously, having received trauma
to the mandible and the mid-face. As he had "no lacerations" and thinking that the pain in his jaws would "eventually disappear", he sought no professional help, thus no radiographs were taken. Initially the limitation of opening of his mouth improved somewhat and the pain and discomfort subsided. There was however, gradual decrease in the patient's ability to open his mouth over the ensuing 8 months' period. On clinical examination the patient's face and jaws showed no abnormalities. On opening
the mouth, there was a marked deviation of the mandible to the left side; the extent of opening measured 11 mm (Fig. 1). On trying to force the mouth to open further, the patient experienced pain in the left zygomatic arch and temporal region. An orthopantomograph (Fig. 2) revealed elongation of the left coronoid process, curving towards the posterior waH of the maxillary sinus. The patient was hospitalized for surgery. Under general anesthesia, through an intraoral approach a left side coronoidectomy was performed. The sectioned coronoid process was delivered with difficulty. The anatomic form of the coronoid process appeared very similar to that of a mandibular condyle; with a full cartilagenous cover (Fig. 3). TIle patient was placed on cloxicillin (orbenin) 500 mg every 6 hours for 5 days. The patient developed moderate edema with resullant trismus. Pain. edema and trismus gradually subsided. After 14 days, the patient could open his mouth up to 25 mm; after 30 days, 33 mm; and after 40 days the opening measured 39 mm (Fig. 4). The patient was seen 3 months later and opening of the mouth reached 41 mm. Pathology Report "Consistent with mandibular condyle plus fibrotic and scar tissue". Section shows normal bone and cartilage. The joint surface is covered by thick fibrous tissue.
Discussion A case of a patient who developed inability to open his mouth fully, after being involved in a car accident 8 months previ-
2. Orthopantomograph showing hyperplastic coronoid process of left side.
Fig.
Fig. 3. Hyperplastic coronoid process sectioned
showing condyloid form covered by cartilage.
HYPERPLASTIC CORONOID PROCESS
Fig. 4. Opening of mouth 1 month post-operatively.
ously. Radiographic examination revealed a left sided hyperplastic coronoid process. Left side coronoidectomy was performed. The gross specimen of the coronoid process appeared very similar to a mandibular condyle in shape and form, being covered by a cartilagenous tissue. The pathology report was "consistent with a normal mandibular condyle". After surgery, the patient experienced gradual improvement of opening of his mouth. Over a period of 3 months, opening reached 41 mm, in comparison with 11 mm pre-operatively.
2. ALLISON, M. L., WALLACE, W. R. & DONWYL, H.: Coronoid abnormalities causing limitation of mandibular movement. J. Oral Surg. 1969: 27: 229-233. 3. ANTONI, A. A., BROWN, A. & JOHNSON, J. H.: Osteochondroma of the coronoid process of the mandible: Report of a case. J. Oral Surg. 1958: 16: 514-517. 4. DAVIDSON, 1. S. H.: Unilateral coronoid hypertrophy causing restricted opening of mouth. Br. J. RadioI. 1965: 38: 478-479. 5. DINGMAN, R. O. & NATVIG, P.: Reduced mandibular motion due to osteochondroma of the coronoid process of the mandible. Amer. J. Surg. 1957: 94: 907-910. 6. FINDLAY, 1. A: Restriction of jaw movement due to abnormalities of the coronoid process. Trans. of IV International Conference of Oral Surgeons. Munksgaard, Copenhagen 1973, pp. 269-278. 7. RUSCONI, L. & BRUSAU, R.: Restricted opening of the mouth from symmetrical bilateral hyperplasia of the coronoid processes. J. Oral Surg. 1974: 32: 456. 8. SHIRA, R. & LISTER, L.: Limited mandibular movements due to enlargment of the coronoid processes. J. Oral Surg. 1958: 16: 183191. 9. TROYER, S. H.: Ankylosis of the coronoid process of the mandible to the zygomatic arch subsequent to the surgical correction of prognathism: Case Report. J. Hosp. Dent. Practice 1971: 51: 19-34. Address:
References 1. ALLAN, 1. M. P.& REID, W. H.: Unilateral exostosis of the coronoid process of the mandible. Br. J. Oral Surg. 1969: 5: 2D-24.
147
Bahram Javid Oral Surgery Department School of Dental Medicine Slziraz University Shiraz - Iran
Oral Surg. 1981: 10: 145-147
(Key words: coronoid process; hyperplasia; trauma; surgery. oral)
Unilateral hyperplasia of the coronoid process of the mandible Case report BAHRAM JAVID School of Dental Medicine, Shiraz University, Shiraz, Iran
Unilateral hyperplasia of the coronoid process of the mandible, with the resultant limitation of opening of the mouth, is not a common finding. The exact cause is not known, but etiological factors have been suggested, trauma being the most commonly mentioned. The present patient was involved in a car accident 8 months previously and sustained facial trauma, but without any obvious signs of fracture. ABSTRACT -
(Received for publicatioll 5 March, accepted 25 July 1980)
Unilateral abnormality of the coronoid process of the mandible is one of the causes of limitation of mouth opening. Unilateral coronoid malformation, exostosis, osteoma hyperplasia, hypertrophy and osteochondroma are many names and descriptions given by the authors of over 30 cases reported in the dentalliterature 1 - 9. Trauma is one of the number of etiological factors put forward. Among the other suggested etiological factors are: failure of the cartilagenous growth centers to disappear normally at an early stage of development of the mandible; disturbance in the growth mechanism and vascular disturbances in the coronoid process; increased activity of the temporal muscle, hyperplasia of neoplastic nature and, because of the attached tendon of temporaIis, an osteochondroma lesion of the coronoid process is formed 1 - 9 •
Fractures of the coronoid process of the mandible are not common; they constitute 2 % of all mandibular fractures. Displacement of the fractured segment depends on the line of fracture and pull of the temporalis muscle. ,Displacement of the fractured segment may bring about a locally reactive fibrosis and impingement of the zygomatic arch. Ankylosis of the coronoid process and the zygomatic arch leading to limitation of opening of the mouth has been reported. A number of patients with unilateral hyperplasia of the coronoid process give an history of traumatic or "difficult" tooth extractions. But although other suggestions of possible causes are put forward, no definite single etiological factor is presented.
Case report A 23 year old male presented with a complaint of "inability to open his mouth
0300-9785/81/020145-03$02.50/0 © 1981 Munksgaard, Copenhagen
146
JAVTD
Fig. 1. Limitation of opening of mouth to 11
mm pre-operatively.
fully". He gave a history of a car accident
8 months previously, having received trauma
to the mandible and the mid-face. As he had "no lacerations" and thinking that the pain in his jaws would "eventually disappear", he sought no professional help, thus no radiographs were taken. Initially the limitation of opening of his mouth improved somewhat and the pain and discomfort subsided. There was however, gradual decrease in the patient's ability to open his mouth over the ensuing 8 months' period. On clinical examination the patient's face and jaws showed no abnormalities. On opening
the mouth, there was a marked deviation of the mandible to the left side; the extent of opening measured 11 mm (Fig. 1). On trying to force the mouth to open further, the patient experienced pain in the left zygomatic arch and temporal region. An orthopantomograph (Fig. 2) revealed elongation of the left coronoid process, curving towards the posterior waH of the maxillary sinus. The patient was hospitalized for surgery. Under general anesthesia, through an intraoral approach a left side coronoidectomy was performed. The sectioned coronoid process was delivered with difficulty. The anatomic form of the coronoid process appeared very similar to that of a mandibular condyle; with a full cartilagenous cover (Fig. 3). TIle patient was placed on cloxicillin (orbenin) 500 mg every 6 hours for 5 days. The patient developed moderate edema with resullant trismus. Pain. edema and trismus gradually subsided. After 14 days, the patient could open his mouth up to 25 mm; after 30 days, 33 mm; and after 40 days the opening measured 39 mm (Fig. 4). The patient was seen 3 months later and opening of the mouth reached 41 mm. Pathology Report "Consistent with mandibular condyle plus fibrotic and scar tissue". Section shows normal bone and cartilage. The joint surface is covered by thick fibrous tissue.
Discussion A case of a patient who developed inability to open his mouth fully, after being involved in a car accident 8 months previ-
2. Orthopantomograph showing hyperplastic coronoid process of left side.
Fig.
Fig. 3. Hyperplastic coronoid process sectioned
showing condyloid form covered by cartilage.
HYPERPLASTIC CORONOID PROCESS
Fig. 4. Opening of mouth 1 month post-operatively.
ously. Radiographic examination revealed a left sided hyperplastic coronoid process. Left side coronoidectomy was performed. The gross specimen of the coronoid process appeared very similar to a mandibular condyle in shape and form, being covered by a cartilagenous tissue. The pathology report was "consistent with a normal mandibular condyle". After surgery, the patient experienced gradual improvement of opening of his mouth. Over a period of 3 months, opening reached 41 mm, in comparison with 11 mm pre-operatively.
2. ALLISON, M. L., WALLACE, W. R. & DONWYL, H.: Coronoid abnormalities causing limitation of mandibular movement. J. Oral Surg. 1969: 27: 229-233. 3. ANTONI, A. A., BROWN, A. & JOHNSON, J. H.: Osteochondroma of the coronoid process of the mandible: Report of a case. J. Oral Surg. 1958: 16: 514-517. 4. DAVIDSON, 1. S. H.: Unilateral coronoid hypertrophy causing restricted opening of mouth. Br. J. RadioI. 1965: 38: 478-479. 5. DINGMAN, R. O. & NATVIG, P.: Reduced mandibular motion due to osteochondroma of the coronoid process of the mandible. Amer. J. Surg. 1957: 94: 907-910. 6. FINDLAY, 1. A: Restriction of jaw movement due to abnormalities of the coronoid process. Trans. of IV International Conference of Oral Surgeons. Munksgaard, Copenhagen 1973, pp. 269-278. 7. RUSCONI, L. & BRUSAU, R.: Restricted opening of the mouth from symmetrical bilateral hyperplasia of the coronoid processes. J. Oral Surg. 1974: 32: 456. 8. SHIRA, R. & LISTER, L.: Limited mandibular movements due to enlargment of the coronoid processes. J. Oral Surg. 1958: 16: 183191. 9. TROYER, S. H.: Ankylosis of the coronoid process of the mandible to the zygomatic arch subsequent to the surgical correction of prognathism: Case Report. J. Hosp. Dent. Practice 1971: 51: 19-34. Address:
References 1. ALLAN, 1. M. P.& REID, W. H.: Unilateral exostosis of the coronoid process of the mandible. Br. J. Oral Surg. 1969: 5: 2D-24.
147
Bahram Javid Oral Surgery Department School of Dental Medicine Slziraz University Shiraz - Iran