Abstract
Mandibular condylar osteochondroma (OC) can result in morphological and functional disturbances, including facial asymmetry and temporomandibular joint (TMJ) dysfunction. The aim of this study was to explore the feasibility of endoscope-assisted tumour resection and conservative condylectomy via an intraoral approach. Seven patients with condylar OC were enrolled in this study. Endoscope-assisted tumour resection and conservative condylectomy were achieved intraorally, and no conventional extraoral incision was needed. Direct vision of the magnified and illuminated operative field was realized with the assistance of an endoscope. No facial nerve injury or salivary fistula occurred in any patient. Stable occlusion was realized through postoperative orthodontic treatment. The patients showed no signs of tumour recurrence or TMJ ankylosis during follow-up (range 18–43 months). Endoscope-assisted condylar OC resection and conservative condylectomy via intraoral approach offers great advantages with no significant complications compared with conventional extraoral incisions. The endoscope provides us with a valuable treatment option for this potentially complicated procedure
Osteochondroma (OC) also known as osteocartilaginous exostosis, is one of the most common benign tumours of the long bones, but is rarely found in the facial skeleton. Mandibular condylar OC can result in morphological and functional disturbances, including facial asymmetry and temporomandibular joint (TMJ) dysfunction. The current recommended treatment is surgical excision of the lesion with maximal preservation of the condylar head. The tumour resection of the condylar process is a difficult surgical procedure because of the complexity of the approach and the proximity to vital anatomic structures. The preauricular approach, either on its own or in combination with cervical incisions, is the most used. However, because most OCs are located medial to the condyle, the preauricular approach has its disadvantages. The surgical entry can be compromised due to the zygomatic arch and facial nerve. It is necessary for the articular capsule to be opened for tumour resection. At the same time, the conventional resection has a risk of facial nerve injury and sometimes leaves a prominent facial scar.
To avoid extraoral incisions, attempts have been made to establish an intraoral approach to the treatment of mandibular condylar lesions. Open reduction and rigid fixation of subcondylar fractures has been realized intraorally. Eller et al. tried a transoral approach to the resection of condylar OC and performed a condylectomy successfully in conjunction with a coronoidectomy. However, it is undeniable that the exposure and vision of the surgical field in the oral cavity is compromised due to the limited incision and the deep condylar location. The advent of the endoscope has provided us with a valuable alternative.
Endoscopic surgery has been used more frequently in the head and neck area since the late 1990s. However, its application in condylectomy has seldom been reported. Because the use of the endoscope has advantages, including small incisions, minor tissue damage, and direct vision of a magnified and illuminated operative field, we sought to introduce this device into the treatment of condylar OC. In this study, endoscope-assisted tumour resection was carried out in seven patients with mandibular condylar OC via an intraoral approach.
Patients and methods
From November 2008 to December 2011, seven patients with OC of the mandibular condyle were treated at the Department of Oral and Craniomaxillofacial Science. Patients with severe asymmetric prognathism who needed combined orthognathic surgeries were excluded from this study. The enrolled patients (four women and three men) had a median age of 21.9 years (range 15–27 years). Their mean duration of facial asymmetry before treatment was 3.9 years (range 1–7 years). Occlusal canting and disorders were observed in all patients preoperatively. All patients had an open bite on the affected side and a crossbite on the other side ( Table 1 ). This study had hospital institutional review board approval and informed consent agreements were obtained from all patients.
| Case No. | Age, years | Gender | Affected side | Duration of facial asymmetry (years) | Occlusion canting | Mouth opening (mm) | Follow-up (months) | |
|---|---|---|---|---|---|---|---|---|
| Preop. | Postop. | |||||||
| 1 | 22 | M | L | 5 | Yes | 35 | 39 | 20 |
| 2 | 21 | F | R | 4 | Yes | 33 | 35 | 28 |
| 3 | 24 | F | R | 2 | Yes | 37 | 40 | 18 |
| 4 | 24 | M | L | 3 | Yes | 29 | 37 | 24 |
| 5 | 15 | M | R | 1 | Yes | 40 | 38 | 36 |
| 6 | 20 | F | L | 7 | Yes | 34 | 41 | 32 |
| 7 | 27 | F | L | 5 | Yes | 38 | 35 | 43 |
| Mean | 21.9 | 3.9 | 35.1 | 37.8 | 28.7 | |||
A preoperative thin-cut (1.25 mm), spiral, computed tomography (CT) scan (Light Speed 16, GE, Gloucestershire, UK) was performed. Each patient’s individual anatomy and OC were assessed using Surgicase software (Materialise, Leuven, Belgium) in multiplanar (axial, coronal, and sagittal) and three-dimensional (3D) views. The boundary of the tumour and the osteotomy line was delineated on a 3D reconstruction model based on the CT scan ( Fig. 1 ).
The operations were performed under general anaesthesia through a nasoendotracheal intubation. All patients were placed in supine position with a pillow under their shoulder. The operative team consisted of four people: a chief surgeon, an endoscope assistant, an assistant surgeon who helped to maintain the working cavity using a retractor, and a scrub nurse. Maximum mouth opening was maintained using a standard mouth prop. A buccal incision was made from the level of the mandibular second molar to the level of the maxillary teeth. Buccal and lingual mucoperiosteal flaps were elevated. Subperiosteal dissection along the mandibular ramus was carried out until the mandibular condyle was fully exposed. Careful subperiosteal dissection resulted in a clean and dry cavity. Two large malleable retractors were placed laterally and medially to protect the buccal and lingual soft tissue. To sufficiently expose the condyle, a coronoidectomy was necessary. A titanium plate was placed prior to the osteotomy so that the coronoid could be secured subsequently in the exact anatomic position. The coronoid process was osteotomized at the level of the mandibular notch using a reciprocating saw and osteotome.
The position of the incision and mobility of the soft tissue in this region allowed the 4-mm diameter, 30° endoscope (Stryker Corporation, Michigan, US) to be placed in the wound and to be oriented parallel to the posterior border, with direct access to the entire ramus/condyle unit (RCU). With the endoscope in place, bony anatomic landmarks of the RCU were identified. The TMJ capsule and lateral pterygoid muscle were dissected off the condylar head and neck. All operations were performed in the inferior synovial cavity of the TMJ, so the articular disc was well preserved. A titanium screw tied with a stainless steel wire was fixed on the exostosis, which could be used to facilitate the dissection and removal of tumours. The osteotomy was performed according to presurgical planning using a long-shafted reciprocating blade. Then the lesion with the affected condyle was removed ( Fig. 2 ). After tumour excision, the osteotomized section was trimmed to a smooth surface. Negative pressure drainage was placed in the channel and the wound was then closed.
