Учебники / Color atlas of temporomandibular joint surgery Quinn

194

FIG. 7.31

A

Color Atlas of Temporomandibular Joint Surgery

Because of its potential effect on the occlusion, proper positioning of any alloplastic joint prosthesis is extremely important. The patient must be placed in stable intermaxillary fixation when the condylar prosthesis is being placed. The prosthesis should be secured with two screws initially, and then the mandible should be manipulated through a range of motion to ensure that centric occlusion can be achieved and the prosthesis does not subluxate or dislocate. Condylar prostheses are available in stock lengths of 45, 50, and 55 mm. The prosthesis should be secured with six to eight 2.7-mm screws, and care must be taken not to violate the neurovascular bundle in the inferior alveolar canal during placement of the anterior ramal screws. In general, the use of a stock prothesis such as the Christensen can present disadvantages. Because of variability in the contour

E

A, Endaurol and modified Risdon incisions necessary for placemen! of total joint prosthesis. B, Placement

of the incisions for optimal cosmesis.

T e x t

Chapter Seven Autogenous and Alloplastic Reconstruction of the Temporomandibular joint

of glenoid fossae, multiple fossa prostheses are available. Even with this selection, surgeons often experience difficulties in achieving proper fit in patients who have undergone multiple operations and have gross distortion of the normal joint anatomy. In light of this fact, a custom-made prosthesis would be preferable. The well-designed Techmedica system was modeled from a plastic skull fabricated on the basis of three-dimensional computer tomographic scans. A titanium-mesh backing is custom-fitted against the glenoid fossa, and a polyethylene articulating surface is mated to the titanium mesh. A custom-made metallic condylar prosthesis is then secured to the lateral ramus. T M J , Inc., is also producing a custom fossa and condylar total joint prosthesis from three-dimensional computer tomo-

graphic data. continued on p. 206

Coronoid processes after coronoideclomy for total joint replacement. This is often necessary to gain an adequate range of motion,

195

FIG. 7-32

196	Color Atlas of Temporomandibular Joint Surgery

FIG. 7.33

A B

c

D

E F

A, Preoperative occlusion showing gross aperlognalhia in patient with idiopathic condylar resorption.

B, Postoperative occlusion after bilateral prosthetic joint replacement. C, D, Cephalograms taken before and after bilateral prosthetic joint replacement. The patient had bilateral idiopathic condylar resorption and underwent several unsuccessful orthognatic surgical procedures to correct her apertognathia before the joint replacements. E, F, Lateral views of the patient before and after bilateral joint replacement.

Chapter Seven	Autogenous and Alloplastic Reconstruction of the Temporomandibular Joint	1 9 7
		F I G . 7 . 3 3, C O N T ' D

G

H

G, H, Frontal views of the same patient before and after joint replacement.

1 9 8

Color Atlas of Temporomandibular Joint Surgery

FIG . 7 . 3 4

A B

c

D

E F

A, B, Lateral views showing mandibular projection before and after bilateral joint replacement in a 36- year-old woman with advanced condylar resorption caused by rheumatoid arthritis. C, D, Posterioranterior views of the same patient after bilateral joint replacement. E, CT scan showing marked degeneration of the condylar head in the same patient. F, Acquired apertognalhia secondary to condylar resorption. Note wear facets on mandibular anterior teeth, indicating that this was an acquired malocclusion.

Chapter Seven	Autogenous ami Alloplastic Reconstruction of the Temporomandibular joint	199
		F I G . 7 - 3 4 , C O N T ' D

G H

G, H, Lateral cephalograms before and after surgery to correct apertognathia. The mandible was repositioned in an anterior position and supported by the total joint prosthesis. Augmentation-advancement genioplasly was also performed.

F I G S . 7 . 3 5, 7 . 3 6

Fracture of type I- Christensen condylar prosthesis	Fracture type I-Christensen prosthesis being submerged by heterotopic bone
	formation. This fixation of the prosthesis by bone served to create a
	stress point on the condylar prosthesis at the point where the bone
	formation ceased just above the last ramal screw. Fractures usually
	occurred at this point of metal fatigue on the prosthesis.

200	Color Atlas of Temporomandibular joint Surgery

FIGS. 7 . 37, 7.38

Type l-Christensen condylar prosthesis after removal because of fracture. The prosthesis fractured at the point where the screw holes were not as offset as in the other positions on the condylar strut.

Note design difference between Type l-Christensen condylar prosthesis (fourth from the left) and Type ll-Christensen condylar prosthesis fifth from the left). The increosed thickness of the ramal strut with the offset design of the screw holes eliminated the problem of fracture associated with the Type l-Christensen prosthesis.

FIGS. 7 . 39, 7.40

A panoramic x-ray image of a Christensen total joint prosthesis with a Type II condyle.

Comparison of the Type ll-Chrislensen prosthesis with an all-metal head versus a methyl methacrylale head.

Chapter Seven

Autogenous and Alloplastic Reconstruction of the Temporomandibular Joint

201

FIG. 7.4 1

Posterior-anterior skull film showing patient with Type I prosthesis (right side) and a Type II all-metallic prosthesis (left side). Note that the Type II prosthesis is reinforced, which decreases the risk of fracture.

FIG. 74 2

Type l-Christensen condylar prosthesis after removal because of ankylosis. Note heterotopic bone that had formed circumferenlially around the melhyl-melhacrylale condylar head.

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FIG. 7.43

A

c

Color Atlas of Temporomandibular Joint Surgery

B

D

A, A 29-yeor-old woman who underwent multiple joint procedures before reconstruction of the left joint with a costochondral graft. One year after the unsuccessful operations, she still had chronic pain, swelling, limited mouth opening, and facial palsy. B, A panorex x-ray film shows placement of the costochondral graft, which is secured to the lateral ramus with three screws. C, A coronal CT scan shows the costochondral graft positioned laterally with heterotopic bone formation adjacent to the medial stump of the condylar head. D, Ankylosed rib graft pictured in C.

Chapter Seven	Autogenous and Alloplastic Reconstruction of the Temporomandibular Joi>	2 0 3
		F I G . 7 . 43, C O N T ' D

E

F

G

E, F, Anterior-posterior skull and lateral skull views of the Christensen total joint prosthesis placed after removal of the nonfunctioning costochondral graft. G, Patient 6 months after placement of alloplastic joint

prosthesis.

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