Silicon Interpositional Arthroplasty for Temporo-mandibular Joint Ankylosis

Abstract

Temporo-mandibular joint (TMJ) ankylosis is characterized by a decreased mouth opening which affects mastication, speech, and facial aesthetic. Interpositional arthroplasty using autologous tissue is accepted treatment for TMJ Ankylosis; however, harvesting autologous tissue is associated with additional morbidity. In this article we report our results of silicon interpositional arthroplasty for TMJ ankylosis. 20 patients with TMJ ankylosis were included in the study. All patients underwent standard operative procedure using preauricular incision for release of TMJ ankylosis by excision of at least 1 cm of bony block and insertion of 2 cm thick silicon block in the joint space. Postoperatively early mobilization of TMJ was advised from 3rd day onwards. Post operative result was evaluated by assessing the mouth opening as inter incisor distance (IID). 20 patients (27 joints) of TMJ ankylosis were included in the study. There were 8 male and 12 female patients with age ranged from 3–35 years. According to Sawhney classification bony ankylosis was present as Type-IV (n = 13 joints), Type-III (n = 12 joints) and Type-II (2 joints). Preoperative mean IID was 7.15 mm and post operative mean IID was 43.5. There was no facial nerve paresis, malocclusion or recurrence but infection and extrusion of implant occurred in 1 case each. Silicon interpositional arthroplasty is an effective procedure for the treatment of TMJ Ankylosis; as it restores mouth opening and function, maintains the vertical ramus height, and prevents re-ankylosis without any donor site morbidity.

Introduction

Temporo-mandibular joint (TMJ) ankylosis is characterized by a decreased mouth opening which affects mastication, speech, facial aesthetic, oral hygiene and results in psycho-social problems. Apart from these problems TMJ paediatric ankylosis leads to disturbances of facial growth, and sleep apnoea [1]. TMJ ankylosis is mainly caused by trauma (condylar fracture), infection (otitis media and mastoiditis), arthritis, previous TMJ surgery and rarely, systemic diseases like rheumatoid arthritis/psoriasis or ankylosing spondylitis [2–4]. Diverse surgical techniques for treatment of TMJ ankylosis with their outcomes have been reported however, there is no consensus regarding ideal treatment for TMJ ankylosis. Interpositional arthroplasty using autologous tissue is accepted treatment for TMJ ankylosis however harvesting autologous tissue is associated with additional donor site morbidity. To avoid the donor site morbidity alloplastic materials have been used. In this article we report our experience of silicon interpositional arthroplasty for TMJ ankylosis.

Material and Methods

This retrospective study was conducted from 2010 to 2018 in Plastic Surgery Unit of a Tertiary Referral Centre in Central India. Institutional ethics committee’s approval was obtained and all patients gave written informed consent. 20 patients of TMJ ankylosis were included in the study. 15 patients were post traumatic and 5 were post infective. Patients with other causes of trismus like submucus fibrosis were excluded from the study. All patients were successfully intubated for anaesthesia using fibre-optic bronchoscope; none of them required tracheostomy. Severity of TMJ ankylosis was graded according to Sawhney classification into 4 types:

Type I

The deformed condylar head with fibrous adhesions,

Type II

partial bony fusion of deformed head and articular surface,

Type III

A bridge of bone between the mandible and the temporal bone,

Type IV

TMJ totally obliterated by bony block between the ramus and the skull base [5].

All patients underwent standard operative procedure using preauricular incision for release of TMJ ankylosis by excision of at least 1 cm of bony block and insertion of 2 cm thick Medical Grade implantable silicon block (BioPlexus LLC 2020, 5218 M Stockton hill road Kingman AZ 86409 USA) in the joint space. There was no need to fix the silicon block as it fit snugly in the joint space. (Figs. 1, 2) If adequate mouth opening was not achieved, ipsilateral coronoidectomy was added. In cases of bilateral TMJ Ankylosis, same procedure was repeated on contralateral side. Postoperatively, early mobilization of TMJ was advised from 3rd day onwards. Post operative result was evaluated by assessing the mouth opening as (IID). Post-operative complications like infection, extrusion of silicon block, facial nerve function, and mal-occlusion of teeth were recorded. All cases were followed up for minimum 6 months to maximum 5 years.

Fig. 1.

Release of left TMJ ankylosis by excision bony block and insertion of 2 cm thick silicon block in the joint space

Fig. 2.

Release of right TMJ ankylosis by excision of bony block and insertion of 2 cm thick silicon block in the joint space

Results

20 patients (27 joints) of TMJ ankylosis were included in the study. 7 cases were bilateral and 13 unilateral. Of the unilateral cases, 6 were left sided, and 7 were right-sided. There were 8 male and 12 female patients with age ranged from 3–35 years (mean 10.45 years). 15/20 patients were post-traumatic while 5/ 20 were due to otitis media. None of the patient had history of surgery before for TMJ ankylosis. According to Sawhney [5] classification bony ankylosis as Type-IV (n = 13 joints) Type-III (n = 12 joints) and Type-II (2 joints) were present. Preoperative mean IID was 7.15 mm (range 5–10 mm) and post operative mean IID was 43.5 (range-35–48 mm). (Table 1) (Figs. 3, 4, 5, 6) There was no facial nerve paresis, malocclusion or recurrence but infection and extrusion of implant in 1 case each. Patient with infection was salvaged with intravenous antibiotics and in case of extrusion the implant was removed. Since extrusion occurs after 2 months therefore the pseudo joint was formed and patient was continued with mouth opening exercises. Significant clinical improvement in mandibular range of motion was observed in all cases.10 patients (13 joints) were available for review after 5 years showed good mouth opening and no extrusion/infection of silicon implant.

Table 1.

Demographic details and outcome of silicon interpositional arthroplasty

S. No	Age (years)	Sex	Aetiology	Joint involved	Grading of TMJ ankylosis	Mouth opening (pre-op) in mm	Mouth opening (at 6 weeks post-op) in mm	Complications
1	8	F	Post traumatic	Left	Grade III	8	42	Nil
2	3	F	Post infective	Right	Grade III	11	45	Nil
3	11	M	Post traumatic	Left	Grade IV	8	45	Nil
4	7	F	Post traumatic	Bilateral	Grade IV/III	6	35	Nil
5	8	F	Post traumatic	Bilateral	Grade IV/II	5	44	Infection
6	10	M	Post traumatic	Bilateral	Grade IV/III	6	42	Nil
7	10	F	Post infective	Right	Grade III	8	44	Nil
8	6	F	Post traumatic	Bilateral	Grade IV/III	8	45	Nil
9	14	M	Post traumatic	Right	Grade IV	4	45	Nil
10	5	F	Post traumatic	Right	Grade III	8	42	Nil
11	8	F	Post infective	Left	Grade IV	5	45	Extrusion
12	17	F	Post traumatic	Left	Grade II	10	48	Nil
13	10	M	Post infective	Right	Grade III	10	45	Nil
14	7	M	Post traumatic	Bilateral	Grade IV/III	6	42	Nil
15	12	F	Post traumatic	Left	Grade IV	7	45	Nil
16	8	F	Post infective	Right	Grade III	10	45	Nil
17	6	M	Post traumatic	Right	Grade IV	8	44	Nil
18	35	M	Post traumatic	Bilateral	Grade IV/III	5	45	Nil
19	14	F	Post traumatic	Left	Grade IV	6	42	Nil
20	10	M	Post traumatic	Bilateral	Grade IV/III	4	40	Nil

Fig. 3.

Preoperative clinical picture and 3 D CT showing post traumatic bony ankylosis of TMJ

Fig. 4.

Postoperative picture showing good mouth opening

Fig. 5.

Preoperative clinical picture and 3 D CT showing post infective bony ankylosis of TMJ

Fig. 6.

Postoperative picture showing good mouth opening

Discussion

TMJ Ankylosis, depending upon destruction of the joint, can be fibrous/bony or true (intra-articular/false (extra-articular). The goals of TMJ ankylosis management are restoration of adequate mouth opening/mandibular movement, normal occlusion, restoration of ramus height, prevention of re-ankylosis, and normal facial appearance/growth. Surgery is the treatment of choice and Kaban's proposed 7-step protocol for management of TMJ ankylosis which includes excision of the bony ankylosis, coronoidectomy (if needed, on one or both sides) interposition of temporalis myofascial flap, reconstruction of the ramus/ condyle with rigid fixation and early mobilization of the jaw [6]. Currently, three main surgical techniques are employed: Gap arthroplasty, Interpositional arthroplasty and TMJ replacement. There are certain other methods like sliding osteotomy and distraction osteo-genesis which have also been used in the management of TMJ ankylosis [7–10].

Gap arthroplasty is a simple operative procedure in which excision of 1-cm bony block is performed with aggressive postoperative mobilization in order to reduce the recurrence. However, it has a high recurrence rate, open bite deformity and mal-occlusion of teeth. In order to prevent these complications interpositional materials were used at the joint space [11]. These interpositional materials create pseudo joint for functional movements; these materials may be autologous like temporalis muscle/fascia, fascia lata, masseter muscle, full thickness skin/dermis, costochondral graft, and conchal cartilage or alloplastic materials like silicon block/sheet, Teflon, metallic fossa implants, and acrylic marbles [12, 13]. Interpositional arthroplasty gives satisfactory long-term results and low recurrence rates; however, the choice of alloplastic versus autologous materials remains controversial. The problems encountered with the autologous grafts are shrinkage/fibrosis, less bulk, chances of resorption, calcification of cartilage and additional morbidity of harvesting autologous grafts. While alloplastic materials may cause foreign body reaction, infection, extrusion; disintegration and displacement [14–16]. Alloplastic materials are superior to the autologous materials because the operative time is shorter with ease of application, ramus height is maintained, recurrence rate is low and there is no donor site morbidity.

The interpositional or gap arthroplasty does not reconstruct the joint and its associated problems prompted functional restoration of TMJ by prosthesis. TMJ replacement establishes normal occlusion, maintains posterior face height, and avoids re-ankylosis. Many joint replacement system for TMJ have been described and include both autogenous (fibula, metatarsal, clavicle, ileac rest, sterno-clavicular, costochondral) or alloplastic (acrylic, silicone rubber) joint systems [17]. Autogenous joint replacement may lead to donor site morbidity like chest wall deformities and variable behaviour of the graft [18]. Therefore alloplastic joint systems have become the treatment of choice. They allow closer reproduction of the natural anatomy, avoid donor site morbidity, and reduce operation time. Furthermore, they allow for immediate physiotherapy and rehabilitation. However, prosthetic replacement of a Temporo-mandibular joint is technically demanding, expensive and may be associated with serious complications like facial nerve damage, Frey’s syndrome, external auditory meatus perforations, perforation into the middle cranial fossa and severe bleeding from the medial infratemporal fossa [9]. Considering all the complications of TMJ replacement and absence of consensus about accurate indications, optimal timing of surgery and long-term results of joint prostheses they did not become very popular [19]. Some authors advocate the use of costochondral cartilage graft in paediatric TMJ ankylosis as it has the potential to grow; however, growth potential of cartilage grafts are unpredictable with risk of absorption of graft and associated with chest wall deformity [20, 21].

The standard interposition arthroplasty is using temporalis fascia due to its autogenous nature, resilience, adequate blood supply, and proximity to the joint [22]. However, it lacks bulk and leads to contracture of the muscle which may worsen the trismus [23]. Therefore silicon was proposed as interpositional material. The advantage of using silicon is it shapes up well to fit into the condylectomy gap due to its elasticity, it is biocompatible, and maintains vertical ramus height. The silicon block does not get displaced as there is very small space and silicon implant fits snugly. Secondly, body’s reaction creates a pseudosynovial membrane or a fibrous capsule around the implant, thereby stabilizing it. There is no donor site morbidity and no resorption; which makes it superior to other alternatives. Pseudo-joint formed in these patients is analogous to TMJ without meniscus [24, 25].

In our study, all patients had preoperative mean IID of 7.15 mm which increased to mean 43.5 mm postoperatively. All patients had normal occlusion and no recurrence at 6 months follow-up. Extrusion of implant occurred in 1 case (5%).

Immediate postoperative physiotherapy in the form of mouth opening exercises is very important for the prevention of re-ankylosis, stretching the muscles to their original length and for regaining muscular strength. Furthermore, early mouth opening exercises also reorganized newly formed joint space [26]. The choice of TMJ ankylosis management depends upon patient’s age, aetiology and surgeon’s preference [27]. However, interpositional arthroplasty still remains the most popular and commonly performed technique.

Conclusion

Silicon interpositional arthroplasty is an effective procedure for the treatment of TMJ Ankylosis; as it restores mouth opening and function, maintains the vertical ramus height, and prevents re-ankylosis without any donor site morbidity.

Author contributions

PA: conceptualization, data collection, data analysis, manuscript writing and editing; MPS: data collection, data analysis, manuscript writing; ST: data collection, data analysis, manuscript writing; DS: conceptualization data analysis, manuscript writing and editing

Funding

None.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethics approval

Obtained from institutional ethics committee.

Consent to participate

Obtained from patients.