Recurrent bilateral coronoid hyperplasia: an unusual case

Q 1994 The British Association ofOr.

and Maxilloficial

Surgeon\

Recurrent bilateral coronoid hyperplasia: an unusual case A. G. Smyth, M. J. C. Wake

Department of Oral und kfaxillofuciul Surgery, The Queen Elizabeth Hospital, Edghaston, Birmingham, UK

SUMMARY. A case of bilateral coronoid byperplasia 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 coronoidcctomy 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 Ityear period.

INTRODUCTION Bilateral coronoid hypcrplasia is a rare condition, though the actual incidence is unknown. The original description in 1957 is attributed to Ginestet et al.,’ and the condition was also reported in the English literature in the same year.2 Giacomuzzi3 recorded 35 previous reports and more recently Totsuka & Fukuda4 listed 49 previous cases. Bilateral coronoid hyperplasia is multiracial with cases occurring in Caucasian, Negro and Asian races. The condition is thought to be of developmental origin with an excessive degree of growth occurring in the coronoid processes of the mandible, which may enlarge to such an extent that they impinge upon the zygomatic bones and restrict jaw opening. The condition is predominantly found in males; however 4 cases have been reported in females.‘-’ Onset tends to occur in the second decade of life and is closely associated with the pubertal period, although the 2 cases reported by York & Cockerham’ occurred in sisters aged 7 and 12 years, who were both premenarchal. The histological nature of the bone is unremarkable except for the increased size of the coronoid processes and consists of normal mature bone. The usual complaint on presentation is of a painless limitation of mandibular opening of slow, progressive onset. The actiology remains unknown, however a number of hypotheses have been advanced and these are included in the discussion. Treatment consists of surgical excision of both coronoid processes followed by vigorous jaw opening exercises.

had progressively declined from the age of 8 years following an adcnoidectomy operation. Attempts to increase his opening at another hospital by stretching under anaesthesia had been unsuccessful. Examination revealed an interincisal jaw gape of only 4 mm (Fig. 2) and an absence of lateral cxcursory movement. Plain radiographs revealed gross enlargement of both mandibular coronoid processes (Figs 3 & 4) and a computcrised tomographic (CT) scan dcmonstrated impingcmcnt upon the inner aspect of the zygomatic bones which accounted for his severe restriction of jaw opening (Fig. 5). A bilateral coronoidotomy with section through the bases of both coronoids was performed from an intraoral

Case history A 15-year-old male (Fig. 1) of West Indian descent was referred in 1981 to the Department of Oral and Maxillofacial Surgery, Queen Elizabeth Hospital, Birmingham, with severe limitation of mouth opening. The patient and his mother stated that his degree of opening

Fig. 1 - Patient aged 15 years on presentation in 1981 (note rctrognathia).

Recurrent bilateral coronoid hvoernlasia: an unusual case

101

Fig. 2 -Severe limitation ofjaw gape with 4 mm interincisal opening (note class II incisor relationship).

approach and the interincisal opening intra-operatively was increased to 50 mm with active stretching. It was not possible to rcmovc the coronoid processes intraorally, therefore the intraoral incisions were closed and the coronoids approached extraorally via a bitcmporal flap. A ‘false’ joint was found between the coronoid process on each side with the inner surface of the zygomatic bones and these were resected with the bony processes (Fig. 6). Histological examination of the resected specimens showed that the coronoids consisted of normal mature bone, however a joint capsule lined by areas of synovium was present on both specimens at the site of contact between coronoid and zygoma. lmmediately post-operatively the patient could achieve an interincisal opening of 35 mm: hovvevcr this declined to 15 mm over the next 5 weeks despite jaw cxerciscs. Manipulation under anaesthesia was performed at that time and sub-masscteric pcriosteal relieving incisions were placed. New bone formation with fibrous tissue was noted at the sites of previous excision and this was contirmed histologically as woven bone. Subsequent to this procedure. it was possible to increase the mandibular opening with a gag to over 40 mm. Over the course of the following year his gape gradually reduced from 30 mm to 23 mm. Unfortunately, the patient was lost to follow-up over the next 5 years, however in 1989 at the age of 23 years he was referred again by his gcncral practitioner with difficulty in opening his mouth. His interincisal opening at that time

Fig. 3 - OPG

( 1981) showin_e large coronoid processes (outlined)

Fig. 4 - OM view (coronoids outlined).

was 11 mm and it was noted that he had developed significant mandibular progmathism with a buccal crossbitc on the right side. An orthopantomogram revealed that the coronoid processes had completely reformed to their previous extent (Fig. 7) and a repeat CT scan demonstrated a further pscudoarthrosis of the right coronoid process with the zygomatic bone (Fig. 8). A further bilateral coronoidcctomy was performed through a combined intraoral and bitcmporal approach and the impacted wisdom teeth were also removed. Hc was commenced on disodium etidronate (Didronel) for 3 months postoperatively. The intcrincisal opening of 40 nun was maintained and 1 year postoperatively had increased to over 50 mm, however the degree of mandibular prognathism significantly worsened to a gross class 111 relationship (Figs 9 & 10). Acromegaly was considered and the opinion of an endocrinologist was sought. No evidence of systemic disease was found and in particular no abnormalities of growth hormone were apparent. Therefore a mandibular setback with bilateral sagittal split osteotomies was performed. During this admission a glycosuria was detected leading to a subsequent diagnosis of diabetes, which has been managed by diet control alone.

102

British Journal of Oral and Maxillofacial Surgery

Fig. 5 - CT scan (IY81). Note bilateral contact of coronoid processes with zygomatic bones (arrowed to show site ofjoint formation). To date, there has been no further evidence of coronoid process reformation and his interincisal opening has remained within normal limits.

DlSCUSSION

Bilateral coronoid hyperplasia can be distinguished from unilateral coronoid hyperplasia which is a more common condition. The unilateral variety, first described by Brandt,8 results in a painless limitation of mouth opening: however there is usually marked deviation of the jaw towards the affected side. In contradistinction to the bilateral condition, unilateral

Fig. 6 -(A) Right and (B) left resected coronoids.

Note attachment

coronoid enlargement is often the result of a neoplastic process with the formation of an osteochondroma or osteoma. Radiographic examination will usually allow the bilateral condition to be readily identified. The aetiology of the condition remains unknown, however several hypotheses have been proposed. Rowe” suggested an endocrine influence with an exaggeration of the normal growth pattern of the coronoid processes responding unduly to such a stimulus. Lyon and Sarnat” suggested increased activity within the temporalis muscle may account for the enlargement of the coronoid process. Trauma has also been implicated; however: in most of the reported cases there is no history of trauma and therefore a causal relationship with trauma cannot be confirmed. I1 A genetic theory was proposed by Heckcr and Corwin” who suggested a sex-linked mode of inheritance, however the known occurrence in female patients has discounted this theory. A further hereditary or familial aetiology was suggested by York and Cockcrham.5 Van Hoof and Besling13 reported 2 cases occurring in brothers, associated with an inability to extend the interphalangeal joints of the fingers when the wrist is held in dorsiflexion. A similar set of symptoms can occur in patients with the trismus-pseudocamptodactyly syndrome.r4 Our patient stated that the onset of his limitation of mouth opening began immediately after an operation for the removal of his adenoids at the age of 8 years. The timing of the onset was also confirmed by his mother. We postulate that this may indeed have a causal relationship as forceful opening of the mouth with a gag, especially in the presence of increased muscle tone, in order to obtain access to the adenoidal tissue could tear part of the tendinous insertion of tcmporalis muscle onto the coronoid processes or part of the muscle itself, with the subsequent formation of an intramuscular haematoma. Organisation of a haematoma within this region could lead to bony deposition around the coronoid processes and their

of fibrous joint

capsule(arrowed)

Ikcurrcnt

Fig. 7 - OPG ( 1989) showing

complete

reformation

Fig. 8 - Cl‘ scan ( 1990). Repeat pscudoarthrosis process with qgomatic bone (arrowed).

ofcoronoid

bilateral

coronoid

hyperplasia:

an unusual

case

103

processes.

of right coronoid

enlargement. This form of trauma would: of course: need to be bilateral. Shira and Listerr’ and Marran’ both reported cases of bilateral coronoid hyperplasia and mention a past history of removal of tonsils in their patients, although it is difficult to establish a causal relationship in these cases. Rowe’ stated that whilst a false joint is occasionally seen with unilateral coronoid hyperplasia between the coronoid process and the zygomatic bone, there is an absence of false joint formation in the bilateral condition. Our case clearly demonstrates that false joint formation can occur in the bilateral condition (Fig. 6). Reformation of the coronoid processes to their original extent has not been reported previously. Monks” suggested in his report that an attempt at

Fig. 9 - Gross mandibular

prognathism

(age 25 years)

reformation of the left coronoid process could be occuring in his case, following a right intraoral coronoidotomy and left extraoral coronoidectomy. Hall et ~1.‘~ also noted an indication of regeneration of the right coronoid process on panoramic zonograms taken 2 years post-operatively. Our case demonstrates that complete bilateral regeneration is possible. This recurrence of the hyperplastic coronoids does not negate our hypothesis of aetiology, as the surgical excision of the coronoids will lead to further haematoma formation in this area in a patient

104

British Journal

of Oral and Maxillofacial

Fig. 10 - Lateral cephalogram mandibular relationship.

( 1991) showing

Surrerv

gross class III

who perhaps has an increased capacity for bone regeneration. Following the release of the jaw and a return to normal function, our patient demonstrated an abnormal pattern of growth of the mandible after the age of 25 years which required surgical correction. His recent development of diabetes mellitus may bc the first indicator of an underlying systemic disorder of growth, despite the previous normal investigations. The treatment of bilateral coronoid hyperplasia is surgical resection of the enlarged coronoid processes. WC agree with Haytcr and Robertson’g that the bicoronal flap provides excellent access to this region, however we combine this with an initial intraoral approach to ensure complete detachment of the tcmporalis muscle off the mandible and a low level coronoidotomy bone cut. The value of diphosphonate therapy is uncertain. Didronel was not used after the first coronoidectomy but was prescribed for 3 months after the second similar operation which was not complicated by any new bone deposition or abnormal calcification. Diphosphonates suppress levels of alkaline phosphatasc, reduce bone turnover and exert an inhibitory effect on the secretory and mitotic activity of osteoblasts2’ These effects have been put to therapeutic use in the management of myositis ossifcans21 and also in the prevention22 and managemcnt23 of heterotopic ossification which is occasionally seen in patients with spinal cord injuries. Stover et a1.24 also reported a reduced incidence of recurrent heterotopic ossification after operation when diphosphonates were given. Bilateral coronoid hyperplasia is an uncommon cause of limited mouth opening, however, maxillofacial surgeons should be familiar with the presentation, diagnosis and treatment of this condition as it is likely that it is not as rare as was previously believed. References I. Ginestct G, Dupuis A. Merville L, Guerin J, Dondey PL Constriction des machiores d’origine coronoido-malaire. Revue de Stomatol 1957; 58: 233 237.

2. Van Zilc WN. Johnson WB. Bilateral coronoid process exostoses simulating partial ankylosis of the temporomandibular joint: report of a case. J Oral Surg 1957; 15: 72-77. 3. Giacomwri D. Bilateral enlargement of the mandibular coronoid processes: review of the literature and report of a case. J Oral Maxillofac Surg 1986; 44: 728 73 I. 4. Totsuka Y, Fukuda H. Bilateral coronoid hypcrplasia. J Craniomaxillofac Surg 1991: 19: 172-177. 5. York BV, Cockerham < Bilateral hyperplasia of the coronoid uroccsses in siblines. Oral Sure Oral Mcd Oral Pathol 1983: 56: 584-585. 6. Krcutz RW: Sanders B. Bilateral coronoid hypcrplasia resulting in severe limitation of mandibular movement. Oral Surg Oral Med Oral Pathol 1985; 60: 482-484. 7. Kraut RA. Bilateral coronoid hyperplasia: report of two cases. J Oral Maxillofac Surg 1985; 43: 612-614. congenitale de l’apophysc coronoid 8. Brandt K. Deformation du maxillaire infericur. Acta Orthop Stand 1943; 14: 219. 9. Rowe XL. Bilateral developmental hynerolasia of the mandibular coronoid process. Br J Oral S*urg 1963; I: 90-104. IO. Lvon LZ, Sarnat BG. Limited owning of the mouth caused bv enlarged coronoid processes. J Am D&t Assoc 1963; 67: . 644650. Il. Tucker MR, Guilford WB, Howard CW. Coronoid process hyperplasia causing restricted opening and facial asymmetry. Oral Surg Oral Med Oral Pathol 1984; 58: 130 133. 12. Hccker R, Corwin JO. Bilateral coronoid hyperplasia: review of the literature and reoort of a cast. J Oral Sure 1980: 38: 606 608. 13. Van Hoof RF, Besling WFJ. Coronoid process enlargement. Br J Oral Surg 1973: IO: 339. 348. 14. Yamashita DDR, Arnet GF. Trismus pseudocamptodactyly syndrome. J Oral Surg 1980; 38: 625-630. movements due to 15. Shira RB, Lister RL. Limited mandibular enlargement of the coronoid processes. J Oral Surg 1958; 16: 183.-191. 16. Marrd LM. Bilateral coronoid hvperplasia. a developmental defect. Oral Surg Oral Med OraiPathol 1983; 55: lo^- 13. 17: Monks FT. Bilateral hypcrplasia of the mandibular coronoid processes: a case report. Br J Oral Surg 1978.. 79; 16: 31. 37. 18. Hall RE. Orbach S. Landcsbera R. Bilateral hvncrolasia of the mandibular coronoid processes: a report of twb’cases. Oral Surg Oral Med Oral Pathol 1989: 67: I41 -145. 19. Hayter JP, Robertson JM. Surgical access to bilateral coronoid hypcrplasia using thebicoronal flap. Br J Oral Maxillofac Surg 1989; 27: 487-493. inhibit human 20. Khokhcr MA, Dandona P. Diphosphonates bsteoblast secretion and proliferation. ,Metabolism 1989; 38: 184 187. 21. Smith R, Russell RGG. Woods CG. Myositis ossficans progressiva. Clinical features of eight patients and their response to treatment. J Bone Joint Surg 1976; 58B: 48. 57. 22. Stover SL, Hann HR, Miller M. Disodium etidronate in the prevention of the heterotopic ossification following spinal cord iniurv (preliminary report). Paraplegia 1976: 14: 146-156. in*heierotopic ossification in 23. Subbarao JV. Pseudoarthrosis soinal cord-iniurcd oaticnts. Am J Phvs Mcd Rehabil 1990: 69: 8’8 90. ” 1 24. Stow SL, Nicmann KMW, Miller JM. Disodium ctidronate in the prevention of postoperative recurrence of heterotopic ossikation in the spinal cord injured patient. J Bone Joint Surg 1976; 58: 683-687.

The Authors A. G. Smyth FDSRCS, FRCS Senior Registrar M. .I. C. Wake MBChB, BDS, FDSRCS Consultant Oral and Maxillofacial Suraeon Department of Oral and Maxillofacial Surgery The Queen Elizabeth Hosnital Edgbaston Birmingham B I5 2TH UK Correspondence

and requests

for offprints

Paper reccivcd 5 Fchruary 1993 Accepted 2 September 1993

to A. G. Smyth