Abstract
While coronoidotomy and coronoidectomy remain established procedures in maxillofacial surgery, exceptionally enlarged coronoids pose a special challenge, as their intraoral retrieval may be difficult or impossible. Classical coronoidotomy alone in such situations may risk reattachment and recurrence of trismus. The technique described allows creation of sufficient gap and interpositioning at the coronoid base, allowing achievement of satisfactory mouth opening while minimising the risk for reattachment and relapse.
Intraorally executed coronoidectomy and coronoidotomy are performed routinely for a variety of conditions in oral and maxillofacial surgery. The former is preferred, as the removal of the coronoid process is generally considered necessary for a more stable outcome , otherwise the segment has a tendency for reattachment leading to recurrence of limited mouth opening. This may not always be feasible, and the fractured coronoid is then left behind. Preventing reattachment and relapse then depends on the patient’s commitment to physiotherapy. An alternative intraoral method is described based on excising a segment of the coronoid base.
Case report
A 23-year-old male patient presented with the chief complaint of inability to open his mouth for 15 years. He had sustained trauma to the chin when he was about 7 years old for which he never sought medical attention. He developed a progressive restriction in mouth opening. He had retrogenia with facial assymmetry and deviation of the chin to the right with prominent gonial angles and antegonial notching. Condylar movements were severely restricted with palpable movement on the left side and none on the right. Interincisal opening was about 4 mm, with severe malocclusion and multiple carious teeth. A CT scan showed features suggestive of an extensive bony ankylosis on the right side with marked elongation and thickening of the coronoids bilaterally.
Under fibreoptic nasotracheal intubation and general anaesthesia, the ankyotic mass on the right side was exposed through an Al-kayat and Bramley’s approach. Osteoarthrectomy and ipsilateral coronoidectomy was carried out following which 26 mm mouth opening was achieved. Wedge subcoronoid ostectomy with masseeter muscle interposition (as described below) was carried out on the contralateral (left) side through an intraoral approach, following which 41 mm mouth opening could be achieved. Temporalis muscle was interposed into the gap (right side) where an osteoarthrectomy had been performed for excision of the ankylotic mass.
The patient made an uneventful postoperative recovery and was discharged on the seventh postoperative day with mouth opening of 35 mm. At 6 month follow up, the patient was able to maintain an opening of 35 mm without assistance.
Procedure
The access for this procedure remains the same as for a conventional coronoidotomy and coronoidectomy. Following exposure of the anterior border of the ramus of mandible and coronoid process, the periosteum and muscle attachments are stripped off as high as possible. A channel retractor or a Howarth’s periosteal elevator is placed subperiosteally on the lateral aspect, angulating it towards the sigmoid notch.
The tissues on the medial side are reflected subperiosteally and protected with a periosteal elevator. With a number 702 bur or an osteotome, a horizontal osteotomy is executed as high on the coronoid as possible. A second obliquely directed osteotomy is then executed 1 cm below the first, taking care to terminate it at the sigmoid notch ( Fig. 1 ). The intervening wedge of bone is then delivered intraorally ( Fig. 2 ). After achieving adequate mouth opening, a sliver of masseter muscle from the lateral aspect is mobilised and sutured across the defect to the tissues on the medial side, so as to form a barrier against reattachment of the fractured coronoid stump ( Fig. 4 ). Postoperatively, physiotherapy is instituted as per routine protocol.
