Bilateral Lateral Arthroplasty in a Growing Patient for Type III TMJ Ankylosis

Abstract

A 10 year old male patient reported with a chief complaint of inability to open mouth since 4 years. There was a history of fall from height, following which there was progressive limitation in mouth opening and jaw movements. Clinically there was maximal mouth opening (MMO) of 1–2 mm with restricted protrusive and laterotrusive jaw movements. On radiographic evaluation, there was a bifid condyle appearance which showed a medially displaced condyle along with complete lateral fusion of joint components bilaterally. With a diagnosis of Sawhney’s type III ankylosis, lateral arthroplasty was planned under G.A. for both sides. On 2 years follow-up MMO of 30–34 mm was maintained along with unrestricted protrusive and bilateral laterotrusive movements. In this case, we show that the comparatively less invasive treatment plan of lateral arthroplasty involving preservation of medial condylar stump is adequate for the return of TMJ movements to near normalcy.

Introduction

Variety of diseases affect temporomandibular joint leading to Mandibular hypomobility disorders. Ankylosis of the temporomandibular joint (TMJ) is a disabling condition that causes problems in chewing, speech, appearance, maintenance of oral hygiene and plays a major role in patient’s nourishment status [1]. In 1986, Sawhney was the first to classify TMJ ankylosis radiographically into four types according to the anatomical relationships between the TMJ structure and the osseous fusion [2]. In 1998, Nitzan et al. reported a series of four patients with ankylosis type III underwent a bone fusion resection, and the medially displaced condyles were retained and left in that position [3].Normal functionality of the TMJ was restored for all patients and normal development of mandibles were noticed in two young patients.

Hence, it is believed that whenever the anatomy of the medially displaced condyle is maintained and there is evidence of ankylosis affecting only the lateral part of the joint in ankylosis type III cases, the condyle can be excluded from osteotomy and retained rather than removing and replaced by a graft [4]. In this article, we report a case of type III ankylosis managed by lateral arthroplasty bilaterally in a 10 year old male patient.

Case Report

A 10 year old male patient reported with a chief complaint of inability to open mouth since 4 years with a history of fall from height of 5 feet following which there was progressive limitation in mouth opening and jaw movements. Patient seeked second opinion as no improvement had been attained by physiotherapy as advised earlier. In this instance, there was an old healed scar mark at chin region, retrognathic lower jaw with no marked asymmetry of face and severely restricted jaw movements. On clinical examination, maximal mouth opening (MMO) was severely limited, Condylar gliding was not palpated with mouth opening of 2–3 mm, absent protrusive and laterotrusive movements, and no associated tenderness on palpation of the affected joint or the masticatory muscles. Additional findings included palpable bony hard mass in bilateral preauricular region, prominent antegonial notch bilaterally (left side markedly more prominent than that of right side). Proper intercuspation seen with permanent molars occluding in class 2 molar relation. Coronal sections of CBCT showed a bifid condyle appearance with a bony mass measuring approximately 2 cm medio-laterally on both sides (Right side- 22.5 mm and left side- 20.2 mm) (Fig. 1a), bridging the condylar stump with the fossa on the lateral aspect of the joint. On axial sections, the fractured condyle was seen more medially, located in a medio-inferior aspect (Fig. 2a). The diagnosis was established on the basis of history, clinical examination and Cone beam CT available with the patient at the time of presentation. Based on the clinical and imaging findings, the ankylotic joints were approached using Al-Kayat and Bramley’s technique, which provided sufficient exposure (Figs. 3a, 4a). On reaching the capsule, the bony mass was exposed via an inverted ‘L’ incision. The fibrous structure suspected to be joint disc was preserved to allow functional remodelling at a later stage. The osteotomy of the ankylotic mass was performed by angulating the inferior osteotomy cut with an upward bevel in order to preserve the medial condyle. The lateral ankylotic mass was removed and once the functional movements and range of movements of medial condyle was confirmed, the rest of the stump was contoured giving the condylar neck and head the final shape and creating a large gap between the glenoid fossa and the stump (Figs. 3b, 4b). Intraoperative MMO of 38 mm was achieved (Fig. 5). Postoperative radiographs confirmed the intact medial condyle (Figs. 1b, 2b). Post-operatively aggressive physiotherapy was started in order to prevent relapse of the ankylosis and to maintain the maximal mouth opening (MMO) achieved. On 2 years follow up, MMO was maintained at around 27–28 mm along with unrestricted laterotrusive and protrusive movements.

Fig. 1.

Coronal section of CBCT. a Preoperative view, b postoperative view

Fig. 2.

Axial section of CBCT. a Preoperative view, b postoperative view

Fig. 3.

Intraoperative photograph of Right TMJ. a Exposure and Osteotomy cuts, b post resection of ankylotic mass showing gap below the zygomatic arch region

Fig. 4.

Intraoperative photograph of Left TMJ. a Exposure and Osteotomy cuts, b post resection of ankylotic mass showing gap below the zygomatic arch region

Fig. 5.

Intraoperative Maximal mouth opening

Discussion

The surgical approach taken for TMJ ankylosis treatment requires thorough knowledge with adequate preoperative planning and judicious skills. When it comes to ankylosis release surgery, the treatment plan can be viewed at approaching type III and type IV in different manner. In the ankylosis type IV cases, where the entire anatomy of the joint components such as the condyle, disc and glenoid fossa are bridged together by an osseous fusion and disturbed beyond recognition from each other, a comparatively more aggressive approach is required. Whereas in ankylosis type III cases, the bony fusion occurs between the mandibular ramus and the zygomatic arch and whenever the fractured displaced condyle maintains its basic anatomical structure, it is possible to go for the sectioning of laterally fused mass retaining the medially displaced condyle and still achieve treatment outcomes by repositioning the original joint disc. In the surgeon’s experience, graft procedures provide no added advantage over that offered by a lateral arthroplasty along with the preservation of the residual condyle.

The medially displaced condyle might regain its normal functionality as well as preservation of growth potential while avoiding the comorbidities associated with graft surgery. Secondly, the height of the remaining mandibular ramus remains the same, which reduces the risk of developing any occlusal discrepancies. An additional coronoidectomy should be performed whenever necessary in order to achieve a sufficient range of improvement in mouth opening in this procedure as it posts less stress on patient in terms of postoperative physical therapy and helps reduce the risk of recurrence. Postoperative physiotherapy plays a major role in this rationally conservative approach. Postoperative physiotherapy should begin as early as possible, in this case, radiographic examination played a vital role in developing the preoperative plan and in evaluating the efficiency of surgical skills. Radiographic findings enabled the identification of the type of ankylosis, the residual condyle size along with assessment of medio-lateral expansion of ankylotic mass and the condyle’s relationship with the glenoid fossa. The thickness and length of the condylar neck was also assessed using preoperative CBCT. Surgeons may find it difficult to intuitively assess the thickness of the osteotomy when resecting the bone fusion on the lateral side of the condyle, which may lead to excessive bone resection and a weakening of the condyle neck. Using CBCT, the measurements were made in three dimensions and the angulation of osteotome and the thickness of the mass to be removed was predicted preoperatively. Osteotomy thus, was done thereby reducing the anticipated risks such as complete condylectomy or weakening of the residual stump due to excessive removal. Also, the joint disc which was seen as a rarefaction of radiolucency between condyle and glenoid fossa in CBCT was identified intra-operatively and preserved. He et al. believed that the absence of a relatively complete disc or adipose tissue in the joint space can lead to significant increases in the re-ankylosis rate [5]. In a study of 791 patients with TMJ ankylosis, Mehrotra et al. mentioned dermal fat interposition arthroplasty should be considered as an important choice for management of TMJ ankylosis [6].

Conclusion

The outcomes of the present case by retaining the medially displaced condyles retained in ankylosis type III as the basic anatomical structure was appreciable were promising. Further, it has been shown that a lateral arthroplasty that involves only the resection of the lateral fusion of joint components and preserving the medial condyle to function without replacing the joint can be sufficient to release type III TMJ ankylosis. This method may enable young patients to maintain the growth potential of the mandibular ramus without altering its vertical dimension.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Compliance with Ethical Standards

Conflict of interest

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Informed Consent

Written and informed consent was obtained from a legally authorized representative and patient for the treatment plan, management strategy and for a compliant follow-up during the post-operative period for this case report.