Epithelial inclusion cyst in the temporomandibular joint after a dermal graft

Histological evaluation of full thickness skin as an interpositional graft in the rabbit craniomandibular joint

PURPOSE

The purpose of this study is to determine the histological fate of the full thickness skin graft when placed into the temporomandibular joint using a rabbit model.

MATERIALS AND METHODS

Fourteen New Zealand white rabbits were used and divided into 3 groups. Two rabbits were used as controls (Group A) whereby a sham operation was undertaken with an incision made and immediately repaired without breaching the joint space of the left craniomandibular joint (CMJ). In 6 rabbits (Group B), the joint capsule of the left CMJ was surgically breached but the articular disc was preserved and the wound was repaired. The remaining 6 rabbits (Group C) also had the left CMJ surgically exposed with preservation of the articular disc and the interpositional placement of a full thickness skin graft that was taken from the skin of their necks. All grafts were placed above the articular disc and head of condyle in the superior joint space and firmly secured to the surrounding tissues with nonresorbable sutures. The rabbits were sacrificed at 1, 3, and 5 months after surgery and the left CMJs were histologically prepared and examined under light microscopy.

RESULTS

The condylar head in the regions where the disc was present appeared to closely resemble that of the control rabbits. However, where the disc was breached by inadvertent surgical trauma (Group B), the underlying condyle showed an irregular outline with increased fibrosis and a marked reduction in mature cartilage. In the subarticular bone there was increased osteoblast and osteoclast activity reflecting high bone activity indicative of a remodeling rather than a degenerative process. The interpositional skin grafts in all experimental animals (Group C) were found adjacent to the condyle on the lateral aspect rather than above the condylar head where it was originally sutured in place. Significant atrophy and reduction in the number and size of the skin appendages such as sweat glands and hair follicles was found within the grafted skin of all experimental animals (Group C) compared with normal skin. All the grafts showed evidence of epidermoid inclusion cysts.

CONCLUSIONS

The full thickness skin graft is not a suitable interpositional material for the TMJ because of the high risk of epidermoid cyst formation and the propensity for lateral displacement of the graft even when sutured into the appropriate intra-articular position.

The use of dermis grafts after discectomy for internal derangement of the temporomandibular joint

PURPOSE

The aim of this retrospective clinical study was to review the outcomes of temporomandibular joint (TMJ) discectomy with autogenous dermis used as an immediate interpositional graft in patients with advanced internal derangement of the TMJ.

PATIENTS AND METHODS

Thirty-five joints in 29 patients who presented with advanced internal derangement of the TMJ with degenerate and irreparable discs were identified and included in the study. All patients underwent a TMJ arthrotomy (including 6 bilateral TMJ procedures) that involved removal of the disc (discectomy) and immediate replacement with autogenous dermis graft. Patients were followed up for an average of 2 years.

RESULTS

There was a mean +6.7-mm improvement in maximum interincisal opening, a 66% mean improvement in pain ( P < .001), and a 42% mean improvement in function ( P < .05) after TMJ discectomy with immediate dermis graft replacement. After an average follow-up period of 24.6 months, patients reported good to excellent improvement in their TMJ symptoms in 30 of the 35 joints (85.7%). All patients showed radiologic evidence of varying degrees of condylar remodeling at 6 months or later after surgery. Of the 7 patients who had magnetic resonance imaging (MRI) performed at 6 months or later after surgery, none showed any radiologic evidence of the dermis graft. No clinical evidence of joint sounds such as crepitus was found in 33 of the 35 operated joints.

CONCLUSIONS

This study found that TMJ discectomy can have a significant positive effect on the management of patients with advanced internal derangement of the TMJ who fail to respond to less invasive measures such as splint therapy and TMJ arthroscopy. However, the only advantage of dermis grafts over no grafts seems to be that it can minimize or eliminate joint sounds such as crepitus in the discectomized TMJ. In this study, the dermis grafts did not prevent regressive remodeling of the mandibular condyles.

Long-term magnetic resonance imaging after temporomandibular joint discectomy without replacement

PURPOSE

The intracapsular changes in patients who underwent discectomy without disc replacement were evaluated by magnetic resonance imaging (MRI) to determine the long-term outcome of this procedure.

PATIENTS AND METHODS

Thirty-three patients observed for an average of 9 years 4 months (5 to 24 years) and 10 asymptomatic volunteers underwent MRI using T1- and T2-weighted images and 3-dimensional fast imaging with a steady precession sequence (FISP-3D) technique. The intracapsular changes, especially those in the joint space, were compared with the postoperative clinical findings.

RESULTS

MRI examination of the temporomandibular joint in the 33 patients (35 joints) indicated the presence of tissue with an intermediate or high signal intensity in the joint space. This tissue covered the articular surface of the condyle and fossa. Thirty-two joints had no pain or only occasional, mild pain (3 joints). No patient had severe joint pain or a low signal intensity in the joint space on MRI examination. There was no correlation between joint noise and the presence of a tissue deformity in the joint space. MRI of 2 patients with limited mouth opening showed tissue with high signal intensity in the joint space as well as an exostosis on the eminence and hypertrophy of the condyle.

CONCLUSION

Long-term success is possible with discectomy without replacement. This appears to be attributable to the formation of new tissue between the condyle and fossa that acts as a pseudodisc.

Epidermoid cyst in the temporomandibular joint after a dermal graft

A very rare case of epidermoid cyst of the left temporomandibular join (TMJ) after a dermal graft inserted as the interposing material in the surgical correction of TMJ ankylosis is presented. Two years after the surgery, a cystic lesion the size of a walnut was observed in the TMJ region. The cyst contained an odorless, straw-coloured mucoid fluid and a wall lined by stratified squamous epithelium containing orthokeratin. It contained no hair follicles or sweat glands.

A two-stage procedure for temporomandibular joint disc replacement using free pericranial grafts: a preliminary report

A preliminary study of the use of free pericranial grafts as an alternative to other autogenous or alloplastic materials for temporomandibular joint disc replacement is presented. Postoperative results show improved function and alleviation of other symptoms.

The autogenous dermal graft in temporomandibular joint disc surgery

Repair or replacement of the disc in 58 patients (64 joints) with temporomandibular joint internal derangement was done using an autogenous dermal graft. Long-term follow-up of 3 to 8 years revealed successful elimination of symptoms and restoration of mandibular function in 51 patients (87.9%). The autogenous dermal graft, rather than alloplastic materials, may be the procedure of choice when repair or replacement of the temporomandibular joint disc is indicated.