Interposition Arthroplasty

SURGICAL APPROACHES TO TEMPOROMANDIBULAR JOINT Surgical access to the temporomandibular joint is an exacting procedure. It requires technical skill and a thorough knowledge of anatomy of the area. Several approaches to the TMJ have been proposed and used clinically. The sugical approaches are as follows.

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Submandibular approach Postramal approach Post auricular approach Pre auricular approach Hemi coronal approach Coronal approach Endaural approa

The basic technique for surgical correction of ankylosis includes –  Condylectony  Gap arthroplasty.  Joint reconstruction or Interpositional arthroplasty. Most surgical procedures can be done through a preauricular incision alone. The Popowich’s incision is the most preferable for its obvious advantages. Whenever required, additional submandibular incision can be used for fixation of the graft.

SURGICAL TECHNIQUE The ideal surgical technique perform for the temporomandibular joint ankylosis is Condylectomy with interpositional gap arthroplasty. Procedure This surgery is performed under general anesthesia with naso-tracheal intubation. Intubation creates problem in children with bird face appearances so blind intubation is preferred. The method of blind intubation in the conscious patient is done with the tube being passed after the nose has been sprayed with cocain, further cocainization of the pharynx and larynx being achieved via the tube itself once the tube is in place, the operation can be performed under gasand-oxygen anaesthesia,and the tube left in situ until the patient is again fully conscious. Access to the joint is made for which variety of incision are recommended but preauricular approach is the most accepted approach in this case . Popowich's incision which is the modification of Preauricular incision Here the upper part of the incision is extended in a question mark(?) fashion over the temporal area to give better access. Osteotomy is carried out with the help of the

surgical bur at the level of condylar neck.Vital structure on the medial surface of the condylar neck should be protected by using special condylar retractor, inserted prior to the bony cut. The condylar head then should be separated from the superior attachment carefully. Then create a gap of at least 1 to 2 cm .A gap was created by removing the fibrous osseous tissue and bone is removed by using a large round bur, until the medial bone is thinned out enough to be readily removed by hand chisel or osteotome .It is important to create a gap of equal dimension both laterally and medially, so that the possibility of medial reankylosis due to bone contact is avoided . After creation of the gap a barrier( Autogenous or Alloplastic) material is inserted between the cut bony surfaces to minimize the risk of recurrence and to maintain the vertical height of the ramus.

INTERPOSITIONAL MATERIALS The interpositional materials used in the surgery of temporomandibular joint ankylosis are:

Autogenous material     

Cartilaginous grafts Temporalis muscle Temporalis fascia Fascia lata Dermis

Alloplastic material Metallic

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Tantalum foil/plate Stainless steel Gold Titanium

Non metallic  Silastic  Teflon  Acrylic  Ceramic implant

INTERPOSITION ARTHROPLASTY USING AUTOGENOUS COSTOCHONDRAL GRAFT Now a day's Costochondral graft interposition arthroplasty is the most accepted method for the treatment of Temporomandibular Joint ankylosis. This was the mainstay of the Rx of ankylosis for more than 100 years.

Goals The goals of use of Autogenous Costochondral grafts are : 1. To replicate structurally normal joint anatomy. 2. To provide functional articulation. 3. To established an area where adoptive growth can occur in children.

Advantage: The advantages of costochondral grafts are as follows:  Costochondral graft contains a cartilaginous part which helps in maintain the normal architecture of temporomandibular joint.  Costochondral graft includes biologic and anatomic similarity to the mandibular condyle.  Ease in obtaining and adopting the graft.  Increase mouth opening.  Low morbidity.  Re-generation of donor sites & a demonstrated growth potential in juvenile recipients.

Disadvantage: The disadvantage of Autogenous Costochondral grafts are :  Increased operating time.  Additional surgical site.  Possible potential for reankylosis.  Donor site morbidity- such as pneumothorax, pleuritic pain.  Numb lower lip.  Complication at both donor & recipient sites.  Occlusal change.

 Pain, infection and uncontrolled and unpredictable growth.

LINING OF THE GLENOID FOSSA SIDE BY TEMPORALIS MYOFASCIAL FLAP Temporalis muscle and fascia, as an axial pedicled flap has been used to provide soft tissue lining for TMJ reconstruction. In addition, the flap has been used as an inter positional tissue for the gap arthroplasty procedure for ankylosis. The temporalis flap is commonly based inferiorly on the deep temporal artery and rotated over the zygomatic arch into the joint, with the muscle facing the condylar surface. Other investigators describe anteriorly and inferiorly based temporalis myofacial flap rotated beneath the zygomatic arch and also positioned so that the fascia lines the glenoid fossa and the muscle faces the condyle. Still others recommend that the flap be posteriorly based and passed under the arch. As the vascular supply and the nerves enter the muscle and fascia from an inferior, medial and posterior direction, these anatomic relationships support the use of inferior and posterior based flaps. The principal advantages of the temporalis muscle and fascia flap are their autogenous nature, resilience and adequate blood supply, close proximity to the site.

THE INTERNATIONALLY ACCEPTED PROTOCOLS FOR THE MANAGEMENT OF TMJ ANKYLOSIS The internationally accepted protocols are:

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Early surgical intervention. A gap of at least 1 to 1.5 cm should be created. Ipsilateral coronoidectomy and temporalis myotomy. Contra lateral coronoidectomy and temporalis myotomy is necessary. Lining of the glenoid fossa region with temporalis fascia. Reconstruction of the ramus with Costochondral graft. Rigid fixation of the graft. Early mobilization and physiotherapy for at least six month postoperatively. Regular long term follow up. Cosmetic surgery later.

COMPLICATION The complications of temporomandibular ankylosis before and after the surgery are:

During anesthesia  As the patient can't open the mouth, awake blind intubation has to be done where patient co operation is required which is very difficult to obtain from younger group of patient.

 Because of small mandible and altered position of the larynx, intubation poses a problem.  Aspiration of blood clot, tooth or foreign body during extubation as throat can't be packed prior to surgery.  Danger of falling back of tongue.

During surgery        

Hemorrhage. Damage to auditory meatus. Damage to zygomatic and temporal branch of facial nerve. Damage to glenoid fossa. Damage to auriculotemporal nerve. Damage to parotid gland. Damage to the teeth during opening of the jaw with jaw stretcher. Frey's syndrome

Post operative  Infection.  Open bite.  Recurrence of ankylosis.

Frey's Syndrome It is the incidence, of localized gustatory sweating and flushing, following gun shot wound and suppurative parotitis or any surgery in the pre- auricular region. It is also known as auriculotemporal nerve syndrome. 1. It is characterized by pain in the auriculotemporal nerve distribution. 2. Associated gustatory sweating and occasionally erythema is seen 3. There is flushing on the affected side of the face accompanied by sweating within the hairline, the peri-auricular region and beneath the pinna on eating or starring at food or thinking of any delicious food. 4. A minor starch iodine test is positive in these patients.

RECURRENCE OF TMJ ANKYLOSIS Recurrence of TMJ ankylosis is distressing both to the patient and surgeon. Factors responsible for reankylosis are:  An inadequate gap created between the fragments.

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Missing of the medial condylar stump and leaving it behind. Fracture of the Costochondral graft. Loosening of the Costochondral graft due to inadequate fixation to the ramus. Inadequate coverage of the glenoid fossa surface. Inadequate post operative physiotherapy. Higher osteogenic potential and periosteal osteogenic power may be responsible for high rate of recurrence in children.  The use of alloplastic material causes higher risk of foreign body granuloma and favor ankylosis relapse and hinder rehabilitation.

PREVENTION OF RECURRENCE  Inter positioning of the TMJ with temporal fascia or cartilage may be done to prevent re ankylosis of the joint  Therapeutic treatment (biphosphonates, NSAIDS) and physiotherapy discourage reankylosis of the joint after surgical correction.  Jaw opening exercise must be performed for months to years to maintain the normal mouth opening.  Silastic as alloplastic material could not be used as an inter positional material.

Correction of Facial Deformity Facial deformity and asymmetry can be corrected by distraction osteogenesis, orthognathic surgery- genioplasty or extended sliding genioplasty, saggital split osteotomy. Distraction Osteogenesis: It is the process of generating new bone by the slow stretching of callus in a gap between two bone segments in response to the application of graduated tensile stress across the bone gap. That means bone can regenerate itself without the use of bone grafts or growth promoting factors. It is generally performed in the growing period. Genioplasty: For the correction of the facial deformity Augmentation genioplasty is used to increase the chin projection. It can be done by: • • •

Sliding horizontal osteotomy of the synphysis region. Using autogenous bone graft. Using alloplastic material- silastic, hydroxyapatite etc.

Saggital Split Osteotomy: This procedure is performed on the mandibuler ramus and body. This is accomplished through transoral incision. The osteotomy splits the ramus ansd the posterior bosdy of the mandible sagittally, which allows either setback or advancement.

CONCLUSION Reconstruction of the temporomandibular articulation is one of the most demanding challenges in maxillo facial surgery. Diagnosis and treatment of this oral manifestation is complex, involving several health practitioners such as physicians, dental surgeons, physiotherapists and psychologists. Early surgery can minimize the severity of the restriction of facial growth.

REFERENCES 1) Text book of Oral and Maxillofacial Surgery by Neelima Anil Malik 2) Contemporary Oral and Maxillofacial surgery (4th Edition) by Peterson, Ellis, Hupp, Tucker 3) Text book of Oral and Maxillofacial surgery (2nd Edition) by Vinod Kapoor

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